OPTICAL INSPECTION SYSTEM USING MULTIPLE FACET IMAGING.

专利摘要:
An optical inspection system is provided, which system comprises: (i) an image detector; and (ii) a single optical element, which at least partially surrounds a border of an inspected object; the optical element being adapted to direct light from different areas of the border of the inspected object towards the image detector, so that the image detector simultaneously obtains images of the different areas.
公开号:BE1019945A3
申请号:E2010/0417
申请日:2010-07-08
公开日:2013-03-05
发明作者:Michael Lev；Yossi Cherbis
申请人:Camtek Ltd；
IPC主号:

专利说明:

OPTICAL INSPECTION SYSTEM USING MULTIPLE FACET IMAGING
The present invention relates to optical inspections of objects such as, but not limited to, slices.
Backside and edge / bevel defects are some of the defects that have emerged silently on the surface of the world of performance limiting faults. The presence of contamination on the back side of a wafer can compromise up to 10% of the performance of today's advanced semiconductor devices at multiple process stages such as lithography, diffusion, cleaning, chemical mechanical planarization and film deposition by chemical vapor deposition. Backside defects are not limited to contamination and damage and they also include mechanical scratches that can lead to wafer fractures in subsequent high temperature processes. With 300 mm slices, a more significant occupied area is located at the edge of the slice. Border yield losses, typically 10 to 40% when standardized and compared to a central chip yield, have therefore become a major concern.
Increased automation (less manual handling) and the advanced topography requirement of using only DSP slices (double-sided polished) for 300mm fabrication also resulted in more significant challenges in detecting systematic problems earlier in the production line.
The subject of the invention is an optical inspection system which comprises: an image detector; and an optical element. unique, which at least partially surrounds a border of an inspected object; the optical element being adapted to direct light from different areas of the border of the inspected object to the image detector, so that the image detector simultaneously obtains images of the different areas.
The invention also relates to an optical inspection system which comprises: an image detector; and multiple optical fibers which are arranged to at least partially surround a border of an inspected object; the optical fibers being adapted to direct light from different areas of the border of the inspected object to the image detector, so that the image detector simultaneously obtains images of the different areas.
The invention also relates to an optical inspection system which comprises: an image detector adapted to simultaneously acquire images of a vertex of the border of the inspected object and opposite zones of the border of the object inspected who are close to the summit; and a single optical element that is adapted to direct a light toward the image sensor from the top of the border of the inspected object and from opposite areas of the border of the inspected object that are near the vertex .
The invention also relates to an optical inspection system which comprises: an image detector adapted to simultaneously acquire images of a vertex of the border of the inspected object and opposite zones of the border of the object inspected who are close to the summit; and a fiber array adapted to direct a light toward the image sensor from the top of a border of an inspected object and from opposite areas of the border of the inspected object that are close to the apex.
According to various embodiments of the invention, each of the systems mentioned above may be characterized by one or more of the following features or elements listed below (unless there is a contradiction between an embodiment of the system mentioned above of the system and a feature or element mentioned below): (i) the optical element is a multi-faceted reflector; (ii) the optical element directs light from substantially opposite areas of the border of the inspected object to the image sensor; (iii) the optical element directs light from an upper bevel area and a lower bevel area from the edge of the inspected object to the image sensor; (iv) the optical element directs light from a vertex and at least one bevel region from an upper bevel area and a lower bevel area from the edge of the inspected object to the image detector ; (v) the optical element directs light from an upper bevel zone and a lower bevel zone from the edge of the inspected object; (vi) the optical element directs light from a lower bevel area and an upper area of the border of the inspected object to the image sensor; (vii) the optical element directs light from an upper bevel area, a top area, and an upper area of the border of the inspected object to the image sensor; (viii) the optical element directs light from a lower bevel area, a top area, and a lower area of the border of the inspected object to the image sensor; (ix) the optical element directs light from at least four of an upper zone, an upper bevel zone, a lower bevel zone, a vertex zone and a lower zone of the border of the inspected object to the image detector; (x) the optical element directs light from an upper zone, an upper bevel zone, a lower bevel zone, a vertex zone and a lower zone of the edge of the object inspected to the image detector; (xi) the optical element is able to reduce a difference in length between different optical paths defined between the different zones and the image detector; (xii) the system includes path length adjustment optics which reduces a difference in length between different optical paths defined between the different zones and the image detector; (xiii) the system includes path length adjustment optics; the path length adjusting optics and the optical element substantially equalizing a length of different optical paths defined between the different regions and the image detector; (xiv) the system includes an inspected object stabilizer that maintains a substantially constant distance between an illuminated portion of the border of the inspected object and the optical element during movement of the inspected object relative to the optical element; (xv) the system comprises a device for moving an optical element capable of moving the optical element relative to an illuminated portion of the border of the inspected object in response to an estimated location of the illuminated portion of the border of the inspected object, during a scan of the border of the inspected object with respect to the optical element; (xvi) the optical element comprises multiple parts which differ from each other by at least one optical characteristic; and at a given point of time the different parts of the optical element directing towards the image detector light from different regions of the border of the inspected element; each region of the border of the inspected element comprising at least two areas of the border of the inspected element that are oriented relative to each other; (xvii) the optical element comprises multiple parts which differ from each other by at. less an optical characteristic; and at a given point of time the different parts of the optical element directing towards the image detector light from different regions of the border of the inspected element; each region of the border of the inspected element having a central axis that is substantially perpendicular to a plane defined by an upper surface of the inspected object; (xviii) the image detector is a zone image detector; (xix) the image detector is a linear image detector; (xx) the single optical element comprises at least one pentagonal prism.
Each of the systems mentioned above may include an image sensor which is disposed above the inspected object and which has an optical axis which is substantially parallel to an upper surface of the inspected object; the image sensor comprising a sensing surface that is directed to an upper portion of the multi-faceted reflector; the system further comprising a platen that rotates the inspected object around a center of the inspected object.
Each of the systems mentioned above may include an image detector and a mirror that are disposed above the inspected object; the image sensor comprising a detection surface which is directed towards the mirror, an upper part of the multi-faceted reflector being directed towards the mirror; - the image detector, the mirror and the multi-faceted reflector being rotated by relative to the inspected object so as to scan the border of the inspected object.
The invention also relates to a method for inspecting a border of an inspected object, which method comprises: illuminating the border of the inspected object; directing light from different areas of the border of the inspected object to an image detector by a single optical element which at least partially surrounds a border of an inspected object towards the image detector ; and simultaneously obtaining, by the image sensor, images of the different areas.
The invention also relates to a method for inspecting a border of an inspected object, which method comprises: illuminating the border of the inspected object; directing light from different areas of the border of the inspected object to an image detector by multiple optical fibers which are arranged to at least partially surround the border of an inspected object; simultaneous acquisition by the image sensor of images of the different areas.
The invention also relates to a method for inspecting a border of an inspected object, which method comprises: illuminating the border of the inspected object; directing a light, through a single optical element, from an apex of a border of an inspected object and from opposite areas of the border of the inspected object that are near the apex to an image detector ; and acquiring images simultaneously, by the image sensor, from the top of the border of the inspected object and opposite areas of the border of the inspected object that are close to the vertex.
The invention also relates to a method for inspecting a border of an inspected object, which method comprises: illuminating the border of the inspected object; directing a light, through a network of fibers, from an apex of a border of an inspected object and from opposite areas of the border of the inspected object that are near the apex, to a detector of picture ; and acquiring images simultaneously, by the image sensor, from the top of the border of the inspected object and opposite areas of the border of the inspected object that are close to the vertex.
According to various embodiments of the invention, each of the methods mentioned above may be characterized by one or more of the features or steps listed below (unless there is a contradiction between one embodiment of the mentioned method). above and a feature or element mentioned below): (i) directing a light through an optical element which is a multi-faceted reflector; (ii) directing light from substantially opposite areas of the border of the inspected object to the image detector; (iii) directing light from an upper bevel area and a lower bevel area from the edge of the inspected object to the image detector; (iv) directing light from a vertex and at least one bevel region from an upper bevel area and a lower bevel area of the edge of the inspected object to the image detector; (v) directing light from an upper bevel area and a lower area of the edge of the inspected object; (vi) directing light from a lower bevel area and an upper area of the border of the inspected object to the image detector; (vii) directing light from an upper bevel area, a top area, and an upper area of the border of the inspected object to the image detector; (viii) directing light from a lower bevel area, a top area, and a lower area of the border of the inspected object to the image sensor; (ix) directing light from at least four areas from an upper area, an upper bevel area, a lower bevel area, a top area, and a lower area of the edge of the inspected object to the image detector; (x) directing light from an upper area, an upper bevel area, a lower bevel area, a top area, and a lower area of the border of the inspected object to the image detector ; (xi) reducing, by the optical element, a difference in length between different optical paths defined between the different zones and the image detector; (xiij the reduction, by a path length adjustment optics, of a difference in length between different optical paths defined between the different zones and the image detector; (xiii) the substantial equalization, by an optical path length adjustment and optical element, of a length of different optical paths defined between the different zones and the image detector; (xix) the conservation, by an inspected object stabilizer, of a distance substantially constant between an illuminated portion of the border of the inspected object and the optical element during movement of the inspected object relative to the optical element; (xx) movement, by a moving device the optical element, of the optical element with respect to an illuminated portion of the border of the inspected object in response to an estimated location of the illuminated portion of the border of the inspected object, during a scanning e the border of the inspected object with respect to the optical element; (xxi) directing, at a given time point and by the different parts of the optical element, to the image detector, light from different regions of the border of the inspected element; each region of the border of the inspected element comprising at least two areas of the border of the inspected element that are oriented relative to each other; the optical element comprising multiple parts which differ from each other by at least one optical characteristic; (xxii) directing, at a given time point and by the different parts of the optical element, to the image detector, light from different regions of the border of the inspected element; each region of the border of the inspected element having a central axis that is substantially perpendicular to a plane defined by an upper surface of the inspected object; the optical element comprising multiple parts which differ from each other by at least one optical characteristic; (xxiii) directing a light to an image detector which is a zone image detector; (xxiv) directing a light to an image sensor which is a linear image detector; and (xxv) directing a light through a single optical element that includes at least one pentagonal prism.
Each of the methods mentioned above may include rotating the inspected object around a center of the inspected object while simultaneously obtaining images of the different areas by an image sensor that is disposed above the object. an object inspected and having an optical axis that is substantially parallel to an upper surface of the inspected object; the image sensor having a sensing surface which is directed to an upper portion of the multi-faceted reflector.
Each of the methods mentioned above may comprise the rotation of the image detector, the multi-faceted reflector, at least one illumination element and a mirror which are arranged above the inspected object while simultaneously obtaining images of the different areas by an image detector which comprises a detection surface which is directed towards the mirror, an upper part of the multifaceted reflector being directed towards the mirror.
An optical inspection system, which system can include: a first image sensor, a second image sensor, a support module for supporting and rotating an inspected object that has a border that includes an upper zone, an upper bevel zone, a crown zone, a lower bevel zone and a lower zone; a first optical element for directing light from the upper region, the upper bevel region and the apex region to the first image detector; and a second optical element for directing light from the lower region, the lower bevel region, and the apex region to the second image detector.
The invention also relates to an inspection method, which method may include: supporting and rotating an inspected object which has a border that includes an upper zone, an upper bevel zone, a vertex zone a lower bevel zone and a lower zone; the illumination of the border of the inspected object; directing, by a first optical element, light from the upper area, the upper bevel area and the apex area to a first image sensor; simultaneously obtaining, by the first image detector, images of the upper zone, the upper bevel zone and the summit zone; directing, by a second optical element, light from the lower area, the lower bevel area, and the apex area to a second image sensor; and simultaneously obtaining, by the second image sensor, images of the lower zone, the lower bevel zone and the crown zone.
The subject of the invention is also an optical inspection system, which system may comprise: a first image detector; a second image detector; a support module for supporting and rotating an inspected object which includes a border having an upper zone, an upper bevel zone, a vertex zone, a lower bevel zone and a lower zone; and an illumination unit for illuminating the border of the inspected object; the upper bevel zone being oriented at a greater bevel angle with respect to the upper zone; the first image detector being oriented at a first image sensor angle with respect to the upper region, the first image sensor angle being smaller than the upper bevel angle; the lower bevel angle being oriented at a lower bevel angle with respect to the lower zone; the second image detector being oriented by a second image sensor angle with respect to the lower region, the second image sensor angle being smaller than the lower bevel angle.
The invention also relates to a method for inspection, which method may include: supporting and rotating an inspected object which includes a border having an upper zone, an upper bevel zone, a vertex, a lower bevel zone and a lower zone; the illumination of the border of the inspected object; and imaging the upper bevel region and the upper zone by a first image sensor; imaging the lower bevel region and the bevel area by a second image sensor; the upper bevel zone being oriented at a greater bevel angle with respect to the upper zone; the first image detector being oriented at a first image sensor angle with respect to the upper region, the first image sensor angle being smaller than the upper bevel angle; the lower bevel angle being oriented at a lower bevel angle with respect to the lower zone; the second image detector being oriented by a second image sensor angle with respect to the lower region, the second image sensor angle being smaller than the lower bevel angle.
The present invention therefore relates to an optical inspection system, characterized in that it comprises: a first image detector; A second image detector; A support module for supporting and rotating an inspected object that includes a border that includes an upper zone, an upper bevel zone, a vertex zone, a lower bevel zone and a lower zone; A first optical element, for directing light from the upper zone, the upper bevel zone and the vertex zone towards the first image detector; and a second optical element for directing light from the lower zone, the lower bevel zone and the apex zone towards the second image detector.
The first optical element may include a first segment that is directed to the upper area, a second segment that is directed to the upper bevel area, and a third segment that is directed to the top area.
The system may further include an illumination module for directing light through the first optical element and to the upper zone, the upper bevel zone and the vertex zone.
The illumination module may include a dark background illumination unit.
The system may include a bright field illumination unit.
The system may further include a calibration unit for determining a position of the border of the inspected object and for sending location signals to engines that are arranged to move at least one of the first and second detectors. image according to the location signals.
The system may further include: - a processing unit for analyzing images obtained by at least one of the first and second image sensors to search for suspected slice defects; and an examination unit which includes an examination camera to obtain images of suspected defects.
The examination unit may include a rotation module that rotates the examination camera about an axis so as to change an angle between the examination camera (2420) and the border of the inspected object.
The invention also relates to an inspection method, characterized in that the inspection method comprises: - the support and rotation of an inspected object which comprises a border which comprises an upper zone, an upper bevel zone, a crown zone, a lower bevel zone and a lower zone; - the illumination of the border of the inspected object; Simultaneously obtaining, by the first image detector, images of the upper zone, the upper bevel zone and the summit zone; and simultaneously obtaining, by the second image detector, images of the lower zone, the lower bevel zone and the crown zone.
The method may include directing a light through the first optical element that includes a first segment that is directed to the upper area, a second segment that is directed to the upper bevel area, and a third segment that is directed to the area. of summit.
The first optical element may further comprise a second beam splitter.
The method may further include: - determining a position of the border of the inspected object; and - sending location signals to engines which are arranged to move at least one of the first and second image sensors according to the location signals.
The method may furthermore comprise: analyzing the images obtained by at least one of the first and second image detectors to search for suspected slice defects, and obtaining images of the defects suspected by a examination unit.
The method may include rotating the examination camera about an axis to change an angle between the examination camera and the border of the inspected object.
The invention also relates to an optical inspection system, characterized in that it comprises: an image detector; and a single optical element, which at least partially surrounds a border of an inspected object; the optical element being adapted to direct light from different areas of the border of the inspected object to the image detector, so that the image detector simultaneously obtains images of the different areas; - the image sensor being disposed above the inspected object and having an optical axis which is substantially parallel to an upper surface of the inspected object; The image detector having a detection surface which is directed towards an upper part of the single optical element; the system further comprising a platen which rotates the inspected object about a center of the inspected object.
The single optical element may be a multi-faceted reflector.
The image detector and a mirror may be disposed above the inspected object; the image sensor comprising a detection surface which is directed towards the mirror, and an upper portion of the single optical element being directed towards the mirror; the system comprising a rotation device for rotating at least the mirror and the single optical element with respect to the inspected object so as to scan the edge of the inspected object.
The invention also relates to a method of inspecting a border of an inspected object, characterized in that it comprises: - illumination of the border of the inspected object; and - directing light from different areas of the border of the inspected object to an image detector, by a single optical element, which at least partially surrounds a border of an inspected object, to the detector of the object. 'picture ; - rotating at least the single optical element and a mirror which is disposed above the inspected object while simultaneously obtaining images of the different areas by an image sensor which comprises a surface of detection which is directed towards the mirror, an upper part of the multifaceted reflector being directed towards the mirror.
The method may include simultaneously obtaining, by the image sensor, images of the different areas while the inspected object is rotated about a center of the inspected object; the image sensor being disposed above the inspected object and having an optical axis which is substantially parallel to an upper surface of the inspected object; the image detector having a detection surface which is directed towards an upper part of the single optical element.
The foregoing objects, features and advantages and other objects, features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. In the drawings, similar reference characters designate like elements across the different views, in which: - Figure 1 shows a border of a slice; - Figure 2 shows a slice and a system according to one embodiment of the invention; - Figure 3 shows a border of a wafer and an optical element according to one embodiment of the invention; - Figure 4 shows a portion of a border of a wafer and a portion of an optical element according to one embodiment of the invention; - Figure 5 shows a portion of a border of a wafer and a portion of an optical element according to one embodiment of the invention; FIG. 6 represents a border of a wafer, an upper optical element and a lower optical element according to one embodiment of the invention; FIG. 7 represents a border of a wafer and an upper optical element according to one embodiment of the invention; Figure 8 shows part of a border of a wafer and part of an optical element according to an embodiment of the invention; FIG. 9 represents multiple optical fibers and a border of a wafer according to one embodiment of the invention; - Figure 10 shows a portion of a wafer and an optical element according to one embodiment of the invention; Figure 11 shows part of a wafer and an optical element according to an embodiment of the invention; Figure 12 shows part of a wafer, illumination elements, an optical element and an image detector, according to an embodiment of the invention; Figure 13 is a flowchart according to one embodiment of the invention; Fig. 14 is a flowchart according to one embodiment of the invention; - Figure 15 is a flowchart according to one embodiment of the invention; Figure 16 is a flowchart according to one embodiment of the invention; 17 represents a system and an object inspected according to one embodiment of the invention; FIG. 18 represents a first scanning unit according to one embodiment of the invention; FIG. 19 represents a second scanning unit according to one embodiment of the invention; - Figure 20 shows a first scanning unit according to another embodiment of the invention; FIG. 21 represents a second scanning unit according to another embodiment of the invention; FIG. 22 represents a border of an inspected object and two image detectors according to one embodiment of the invention; FIG. 23 represents a calibration unit according to one embodiment of the invention; FIG. 24 represents an examination unit according to one embodiment of the invention; FIG. 25 represents a second examination unit according to one embodiment of the invention; FIG. 26 represents a first examination unit according to one embodiment of the invention; Fig. 27 shows an inspection method according to an embodiment of the invention; Fig. 28 shows an inspection method according to an embodiment of the invention; Figures 29 to 31 show inspection systems and a wafer according to various embodiments of the invention; and Figures 32 to 33 are process flowcharts according to various embodiments of the invention.
A system and method for optical inspection. The inspection system and method can detect defects that are close to the border of an inspected object (such as, but not limited to, a slice). The system is capable of illuminating multiple facets of the object simultaneously and detecting reflected and / or scattered light from these illuminated facets. The detection can be implemented using a single image detector, such as, but not limited to, a video camera.
The system defines multiple optical paths that deflect reflected light rays from each facet of interest, such that all light rays are focused on the image sensor surface.
The system and method can be used for a variety of purposes (applications) such as, but not limited to, to detect defects of different sizes, up to micron level defects in the upper, near-top-edge surfaces, of apex, near bottom edge and bottom edge at the periphery of thin substrates, such as slices used in the manufacture of semiconductor or microelectromechanical devices (MEMS), or solar cells.
The invention relates to a method. The method includes: illuminating a multi-faceted object using a multi-faceted deflector; collecting reflected light and, in addition or alternatively, scattering from the multiple facets of the object while using the multi-faceted deflector; and detecting defects based on the collected light. Conveniently, two opposite facets of the multiple facets are illuminated simultaneously during illumination. Conveniently, illumination includes illuminating the multi-faceted object with a multi-faceted deflector that includes light guides.
It should be noted that any combination of any step of any method (or methods) illustrated below may be proposed.
It should be noted that any combination of any component of any system (or systems) shown below may be proposed.
For simplicity of explanation, some of the following figures are on a slice. It should be noted that other inspected objects (such as, but not limited to, a thin substrate) may be inspected by any of the systems listed below and by any of the following: processes mentioned below.
Figure 1 shows a cross section of a border of an inspected object such as a wafer 100.
The edge 160 of the wafer 100 comprises five surfaces (facets) of interest that the method and system can inspect simultaneously - an upper facet 110, an upper bevel facet 120, a top 130, a lower bevel facet 140, and a lower facet 150. It should be noted that the upper facet 110 and the lower facet 150 may extend out of the border 160. For simplicity of explanation, they are visualized as comprising only the parts of these facets that are nearby. from the summit 130.
It should be noted that the methods and systems mentioned below can be applied as is to inspect objects having fewer areas of interest, such as having a rectangular cross section, or more.
It should be noted that in some of the following figures, these numbers (110, 120, 130, 140 and 150) are not shown - for convenience of explanation only.
Figure 2 shows a system 500 and a wafer 100 according to one embodiment of the invention.
The system 500 includes an image detector 400, a light source 340, a beam splitter 320, a pair of lenses 310 and 330, and a single optical element such as a multi-faceted deflector 200 which at least partially surrounds a border 160 of the slice 100.
The system 500 may include one or more lenses, apertures, anti-glare devices, optical equalizers, and the like.
It should be noted that refractors can be used in addition to or in place of the deflectors.
The system 500 transfers images of different edge facets 160 and projects them onto an image sensor 400.
The system 500 illustrates an illumination path on the axis which comprises a light source 34 0 and a beam splitter 320. It may, in addition or alternatively, comprise other types of illumination path such as an inclined illumination. Light from an illumination path may be radiated directly onto the object, or may pass through optical fibers or lenses. System 500 light sources may include incandescent lamps, light emitting diodes, arc lamps, flash tubes, a laser and the like. A system 500 light source may be continuous or intermittent, or any combination thereof. The system 500 may also include at least one of the following components: an image processor, a platen, and the like. If, for example, the inspected object is circular, the platen can rotate the object around a central axis.
The multi-faceted deflector 200 simultaneously collects reflected or scattered light from the multiple facets of the wafer 100 and directs the collected light to (even through additional optics such as lenses 310 and 330) the detector. 400. The multi-faceted deflector 200 converts the set of images acquired from the various facets into a plane image.
In the example of Figure 3, the multifaceted deflector 210 comprises three parts - an upper portion 218 which collects light from the upper facet 110 and the upper bevel facet 120 of the rim 160, an intermediate portion 216 which collects light from the apex 130 and a lower portion 220 which collects light from the lower facet 150 and the lower bevel facet 140 of the border 160.
The multi-faceted deflector 210 is followed by a path length adjusting optics (not shown) which reduces the differences between the optical paths of the light passing through the intermediate portion 216 and the light that passes through the upper portion. 218 and the lower part 220. The reduction difference can be quantified in the equalization of the length of the different optical paths.
The path length adjustment optics is illustrated in PCT International Patent Application Serial No. WO07129322A2 entitled "SYSTEM AND METHOD FOR IMAGING OBJECTS" which is incorporated herein by reference.
Path length adjustment optics can pass light through delay lenses or other optical components that have a higher refractive index than the gas.
For example, it may include a delay lens between the upper and lower portions 218 and 220 and the image detector 400 which will virtually shorten the optical length of the optical paths associated with these portions.
The path length setting optics may include path return mirrors. The first reflecting mirror is positioned and inclined with respect to the top of the object so as to reflect an image from the vertex to the second reflecting mirror. The second mirror, in turn, is positioned and inclined to reflect an image from the top of the first mirror to the image sensor 400. A change in the distance between the first and second diverting mirrors can determine the elongation of the path optics of the upper collection path.
In addition or alternatively, a multifaceted deflector 210 can reduce the difference when the upper portion 218 and the lower portion 220 are much wider (along an imaginary horizontal axis) than the intermediate portion 216.
The multi-faceted deflector 210 is made of an optical grade transparent material which is shaped such that rays of light entering from the facets 110, 120, 130, 140 and 150 are reflected to the image sensor 400 , parallel to an imaginary optical axis which extends towards the image detector. It should be noted that although Figure 3 represents a horizontal line, this is not necessarily the case. It should be noted that the whole system can be oriented in any direction, as long as the relative positions of the inspected object and the described system are preserved.
In this embodiment, this reflection is achieved by forming a facet "a" 212 of the upper portion 218 at an appropriate angle and coating it with a reflective material or attachment of a mirror thereto. A similar embodiment may use internal facet reflection "a" using the prism principle. A facet "b" of lower and upper portions 218 and 220 may be undercut or perforated to equalize the optical path lengths of the various light beams.
Figures 4 and 5 show cross-sections of multi-faceted deflector portions according to various embodiments of the invention.
Figure 4 shows a facet "a" 212 which is formed at an angle less than 45 ° with respect to the main axis, so that a light beam "f" incident with a normal angle on the upper bevel facet "E" of the object passes unrefracted through a deflector facet "c" 213, strikes the reflective baffle facet "a" 212 and is reflected to an image detector 400 in a path parallel to the main axis . The deflector facet "b" 211 is inclined such that an incident "g" light beam with a normal angle on an upper facet "d" of the inspected object is refracted when it crosses the facet "b" of deflector 211 and becomes parallel to the beam "f".
Figure 5 shows a deflector facet "a" 212 which forms an angle of 45 ° with the main axis so that it reflects light beams at a right angle. The light beam "f" is refracted when it crosses a facet "c" of deflector 217, while a beam "g" coming from an upper facet "d" 110 passes rectilinearly through a facet "b" deflector 215 and continues parallel to the beam "f".
Similar geometries can be applied to other forms of inspected objects.
In the example of Figure 6, an optical element comprises a pair of multi-faceted prisms such as a pentagonal prism. These are also referred to as upper optical element and lower optical element.
A pentagonal prism is disposed above the inspected object while the second pentagonal prism is disposed beneath the inspected object. Each pentagonal prism transfers a constructed image and can better equalize optical path lengths of light that is reflected at different angles and / or from different locations of the object. These pentagonal prisms can be either installed in a holding frame, or formed by machining a block made of transparent material. As shown in Figure 5, the facets directed to the inspected object may further be formed to refract light beams at normal angles to the object facets.
Figure 7 shows multiple rays of light passing through the upper (upper) pentagonal prism 23.
Figure 8 shows a border 160 (and some of its facets - 110, 120 and 130) and an upper part of a multi-faceted deflector 260 which comprises multiple parts which differ from each other in shape, so that a portion 261 reflects light from an upper facet 110 to an image detector while the second portion 262 is formed to reflect light from the upper bevel facet 120
A deflection facet of the first portion 261 is oriented at an angle of 45 ° to the horizontal and deflects a vertical light from the upper facet 110 horizontally (to the image detector).
A lower facet of the second portion 262 is parallel to an upper bevel facet 120 while another facet is vertical. A light which is reflected at 90 ° from an upper bevelled facet 120 is deflected by the vertical facet of the second portion 262 of 135 ° and exits the second portion 262 in a horizontal direction.
Figure 9 shows multiple fibers 250, 252 and 254 which are arranged to at least partially surround the border 106.
A first group of fibers 250 collects light from an upper facet 110 and an upper bevel facet 120. A second group of fibers 252 collects light from the apex 130. A third group of fibers 254 collects light from a lower facet 150 and a lower bevel facet 140.
These fibers can be held by (integrated into) a multi-faceted deflector, but this is not necessarily the case. The diameter and density of the fibers must correspond to the optical resolution required.
Figures 10 and 11 show a wafer portion 102 (which is rotated about its center) and an optical element 260 according to an embodiment of the invention. A slice 102 is rotated around its center. Figure 12 also shows illumination elements 281 and 282, optical elements 310 and an image detector 400.
The optical element 260 comprises multiple sub-elements (such as sub-elements 261, 262 and 263) which differ from each other by at least one optical characteristic.
The difference can be introduced by a difference of at least one of the following characteristics of the sub-element and, in particular, a surface of each sub-element: a surface quality, a surface coating, an optical characteristic of a surface, a geometric surface shape, a surface material, a surface material treatment, optical characteristics of material, a polarizing effect, a depolarizing effect and the like.
The difference mentioned above may introduce a difference in illumination or collection of light from each sub-element of the wafer which is illuminated by the sub-element and, in addition or alternatively, from which light is collected by this sub-element.
For example, when the edge of the wafer is illuminated from at least one of the possible directions A, B, C and D, the illumination or the collection introduced by each sub-element may differ by its angular coverage, its magnification, polarization, intensity, color filter, spectral range and the like.
During the inspection, wafer 102 is rotated around its center and explores its border toward each sub-element among 261, 262, and 263
The image detector 400 will capture images of the slice border 160 through each of the sub-elements 261, 262 and 263 and may process each of the optically acquired information in a variety of ways.
Therefore, the system 500 acquires, for each region of the slice border, several images-depending on the number of sub-elements of the optical element 260.
Subregions 261, 262 and 263 collect light from regions 271, 272 and 273 of slot 100. Each region may comprise a combination of at least two of an upper zone, an upper bevel zone, a zone vertex, a lower bevel zone and a lower zone.
The system 600 can process image information associated with each of the different sub-elements 261, 262 and 263, individually, depending on the predefined set of operators and rules and / or any combination with data. acquired from the area next to the slice border based on the same or another predefined set of operators and rules.
The system 60 can combine the processing results and analyze a set of multiple images representing an appropriate area on the slice border and decide on found defects and classify them according to the predefined set of operators and rules.
Figure 13 shows a method 600 of inspecting a border of an inspected object, according to an embodiment of the invention.
The method 60 0 begins with a step 610 of illuminating the border of the inspected object. The illumination may include illumination on the axis, off-axis illumination, pulsed illumination, continuous illumination and the like.
Step 610 is followed by a step 620 of directing light from different areas of the border of the object inspected to an image detector, by multiple optical fibers that are arranged to surround at least partially the border of an inspected object.
Each zone can be a facet or part of a facet. A single facet can include multiple areas among the different areas.
Step 620 is followed by a step 630 of simultaneously acquiring, by the image sensor, images of the different areas. Conveniently, these images are not superimposed.
Step 630 may be followed by a storage step 666 and, in addition or alternatively, processing the acquired images. The processing can be performed as part of a defect detection process during which defects in the border of the inspected object are detected. Thus, step 666 may include methods of treating well-known defects, such as comparing with a reference, comparing part of the border with another, comparing with expected results, and the like.
The method 60 can be performed using various systems and optical components, including but not limited to systems and optics shown in FIGS. 2, 3, 4, 5, 6, 7, 8, 10, 11 and 12.
Figure 14 shows a method 700 for inspecting a border of an inspected object, according to an embodiment of the invention.
The method 700 begins with a step 610 of illuminating the border of the inspected object.
Step 610 is followed by a light direction step 720, by a single optical element, from a vertex of a border of an inspected object and opposite areas of the border of the inspected object which are near the top to an image sensor.
Step 720 is followed by a step 730 of simultaneously acquiring images, by the image sensor, of the top of the border of the inspected object and opposite areas of the border of the inspected object that are close to the Mountain peak.
Step 730 may be followed by a step 666 of storing and, in addition or alternatively, processing the acquired images. The processing can be performed as part of a defect detection method in which defects in the border of the inspected object are detected. Thus, step 666 may include methods of treating well-known defects, such as comparing with a reference, comparing part of the border with another, comparing with expected results, and the like.
The method 70 can be performed using various systems and optical components, including but not limited to systems and optics shown in FIGS. 2, 3, 4, 5, 8, 10, 11 and 12. .
Figure 15 shows a method 800 of inspecting a border of an inspected object, according to an embodiment of the invention.
The method 800 begins with a step 610 of illumination of the border of the inspected object.
Step 610 is followed by a light direction step 820, by a fiber network, from an apex of a border of an inspected object and opposite areas of the border of the inspected object that are near the top, towards an image detector.
Step 820 is followed by a step 830 of simultaneously acquiring images, by the image sensor, of the top of the border of the inspected object and opposite areas of the border of the inspected object that are close to the Mountain peak.
Step 830 may be followed by a step 666 of storing and, in addition or alternatively, processing the acquired images. The processing can be performed as part of a defect detection method in which defects in the border of the inspected object are detected. Thus, step 666 may include well-known defect methods, such as comparison with a reference, comparison of a portion of the border with another, comparison with expected results, and the like.
The method 600 may be performed using various systems and optical components, including but not limited to systems and optics shown in FIG. 9.
Figure 16 shows a method 900 of inspecting a border of an inspected object, according to an embodiment of the invention.
The method 900 begins with a step 610 of illumination of the border of the inspected object.
Step 610 is followed by a light direction step 920, by an optic positioned between the border of the inspected object and an image detector, to an image detector and reduction of a difference of light. length between different optical paths defined between different image areas of the border of the inspected object and the image detector. The optics includes: an upper optical element that directs light from at least one of an upper area, an upper bevel area, and a top of the edge of the inspected object to the image sensor; and a lower optical element which directs light from at least one of a lower area, a lower bevel area, and a top of the edge of the inspected object to the image detector.
Step 920 is followed by a step 930 of simultaneously acquiring images, by the image sensor, of the different image areas.
Step 930 may be followed by a step 666 of storing and, in addition or alternatively, processing the acquired images. The processing can be performed as part of a defect detection method in which defects in the border of the inspected object are detected. Thus, step 666 may include well-known defect methods, such as comparison with a reference, comparison of a portion of the border with another, comparison with expected results, and the like.
The method 900 may be carried out using various systems and optical components, including but not limited to systems and optics shown in Figures 2, 3, 4, 5, 6, 7, 8, 10, 11 and 12.
It should be noted that any combination of the steps of any one of the processes 600, 700, 800 and 900 may be provided, as long as the combination does not include steps that contradict each other.
Figure 17 shows a system 1700 and an inspected object 1701 according to an embodiment of the invention.
The system 1700 includes a calibration unit 1710, an examination unit 1720, a first scanning unit 1730 and a second scanning unit 1740. The system 1700 also comprises a support module (denoted 1702 in FIGS. , 20, 21 and 22) which supports and rotates the inspected object 1701.
The inspected object 1701 is circular and is rotated about its axis by the support module. The calibration unit 1710, the examination unit 1720, the first scanning unit 1730 and the second scanning unit 1740 are positioned close to the edge of the inspected object 1701 after the inspected object 1701 is placed on the support module.
The inspected object 1701 can be rotated clockwise and further or alternatively counterclockwise.
A fault detection sequence may include at least one of the following: (i) rotation of the inspected object 1701 once and detection of defects suspected by one or more scanning units, (ii) rotation of the inspected object 1701 multiple times while maintaining the same illumination conditions and / or collection condition during multiple rotations, (iii) rotating the inspected object 1701 multiple times while modifying one or more illumination conditions and / or one or more collection conditions during these multiple rotations; (iv) evaluation or examination of defects suspected by examination unit 1720.
An illumination condition may include a type of illumination (bright background, dark background), illumination polarization, digital illumination aperture, illumination light color, magnification, illumination intensity, an angle of incidence and the like.
A collection condition may include sensor sensitivity, polarization, collection angle, collection digital aperture, filter parameter, magnification, and the like.
Images that are collected during one or more rotations of the inspected object 1701 can be scanned for suspected defects. Images of the same region of the border area may be correlated or otherwise processed to increase the reliability of the defect detection method or to facilitate detection of defects of several types. An analysis rule can declare a suspected defect only if it appears in multiple images of the same region under different illumination and / or collection conditions.
The calibration unit 1710, the examination unit 1720, the first scanning unit 173 0 and the second scanning unit 1740 are spaced from one another. They may be arranged in other configurations than that shown in Figure 17. For example, the examination unit 1720 may be positioned between the first and second scanning units 1730 and 1740.
The calibration unit 1710 can determine a position of the border of the inspected object 1701. It can measure the thickness of the inspected object 1701 and various deviations from its estimated location during scanning and / or examination treatment. The calibration unit 1710 sends location signals to any one of the first scanning unit 1730, the second scanning unit 1740 and the examining unit 1720 which in turn can move their detectors. image or their optics to maintain a desired distance between them and the border of the inspected object.
The determination of the position of the border of the inspected object, the generation of location signals and, in particular, the introduction of displacement between the border of the inspected object and the optics or image sensors require a period of adjustment.
According to one embodiment of the invention, the rotational speed of the inspected object and the distance between the calibration unit 1710 are set to allow completion of these steps before the edge segment of the object. inspected which arrived on the calibration unit 1710 arrives on any of the first scanning unit 1730, the second scanning unit 1740 and the examination unit 1720.
The first scanning unit 1730 includes a first image detector and a first optical element for directing light from the upper region, the upper bevel region, and the apex region to the first image sensor.
The second scanner unit 1740 includes a second image sensor; and a second optical element for directing light from the lower region, the lower bevel region, and the apex region to the second image detector.
Figure 18 shows a first scanning unit 1730 according to one embodiment of the invention.
The first scanning unit 1730 includes a first image sensor 1731 and a first optical element 1732 for directing light from the upper region, the upper bevel region, and the apex area to the first image sensor 1731.
The first optical element 1732 comprises a first segment 1733 which is directed towards the upper zone, a second segment 1734 which is directed towards the upper bevel zone and a third segment 1735 which is directed towards the crown zone.
Each of the first, second, and third segments 1733, 1734, and 1735 includes an inner facet that is parallel to an outer facet of that segment.
The second segment 1734 and the first image detector 1731 are substantially parallel to the upper bevel area.
Figure 18 also shows an illumination module 1736 for directing a light through the first optical element and to the upper zone, the upper bevel zone and the crown zone.
The illumination module 1736 comprises two dark-field illumination units 1737 and 1738 and a bright-field illumination unit 1739.
The first darkfield illumination unit 1737 directs a light through the first segment 1733 of the first optical element 1732 and to the upper zone and the upper bevel zone.
The second darkfield illumination unit 1738 directs a light through the third segment 1735 and to the summit area.
The brightfield illumination unit 1739 directs light through the second segment 1734 and to the upper bevel area. It should be noted that although Fig. 18 shows a first image detector 1731 as being positioned between the upper bevel area and the light-field illumination unit 1739, it could be noted that in practice one unit light-field illuminator 1739 can be arranged in a different position and direct a light to a beam splitter (not shown) which is positioned between the first image sensor 1731 and the second segment 1734.
Figure 19 shows a second scanning unit 1740 according to an embodiment of the invention.
The second scanning unit 1740 includes a second image detector 1941 and a second optical element 1942 for directing light from the lower region, the lower bevel region, and the apex region to the second image detector 1941.
The second optical element 1942 includes a first segment 1943 which is directed to the summit area, a second segment 1944 which is directed to the lower bevel area and a third segment 1942 which is directed to the lower area.
The second segment 1944 and the second image detector 1941 are substantially parallel to the lower bevel area.
Each of the first, second, and third segments 1943, 1944, and 1945 includes an internal facet that is parallel to an outer facet of that segment.
Figure 19 also shows an illumination module 1946 for directing a light through the second optical element and to the lower zone, the lower bevel zone and the crown zone.
The illumination module 1946 comprises two 1947 and 1948 dark-field illumination units and a 1949 light-field illumination unit.
The first darkfield illumination unit 1947 directs a light through the first segment 1943 of the first optical element 1942 and to the apex.
The second darkfield illumination unit 1948 directs a light through the third segment 1945 and to the lower zone and the lower bevel zone.
The 1949 lightfield illumination unit directs light through the second segment 1944 and to the lower bevel area. It should be noted that although Figure 19 shows a second image detector 1941 as being positioned between the upper bevel area and the 1949 lightfield illumination unit, it could be noted that in practice one unit Brightfield illumination 1949 can be arranged in a different position and direct a light to a beam splitter (not shown) which is positioned between the second image detector 1941 and the second segment 1944.
Figure 20 shows a first scanning unit 2030 according to another embodiment of the invention.
The first scanning unit 2030 includes a first image detector 2031 and a first optical element for directing light from the upper region, the upper bevel region, and the apex area to the first image detector 2031.
The first image detector 2031 is vertical and is parallel to the apex area and to an outer surface 2037 of the first optical element.
The first optical element comprises a first segment 2033 which is directed to the upper area, a second segment 2034 which is directed to the upper bevel area and a third segment 2035 which is directed to the top area.
Each of the first, second, and third segments 2033, 2034, and 2035 includes an inner facet that is parallel to an outer facet of that segment. The first optical element also includes two external facets 203 and 203 which are oriented relative to the internal facets. Figure 20 shows a first outer facet 2036 as being parallel to the upper zone and a second outer facet 2037 as being parallel to the crown zone.
The first optical element also includes two additional outer facets 2038 and 2039. A third outer facet 2038 is parallel to the upper facet and is directed to the dark-bottom illumination unit 2041.
In addition, the first optical element also includes a first beam splitter 2051 and a second beam splitter 2052. The first beam splitter 2051 is disposed at the upper right zone of the first optical element.
The second beam splitter 2052 is disposed at the lower right zone of the first optical element.
Figure 20 also shows an illumination module 2040 for directing a light through the first optical element and to the upper zone, the upper bevel zone and the crown zone.
The illumination module 2040 comprises an illumination unit. 2041 light background and two dark-field illumination units 2042 and 2043.
The brightfield illumination unit 2041 directs light through a first beam splitter 2051 over an upper bevel region. Light from the upper bevel region is directed by the first beam splitter 2061 to a first image detector 2031.
The first darkfield illumination unit 2043 directs light through the second beam splitter 2052 to the apex area. The first dark-field illumination unit 2043 is positioned below the first optical element and directs its light through a vertical path to a second outer facet 2038 of the first optical element.
The second darkfield illumination unit 2142 is positioned above the second optical element 2132 and directs its light through a first segment and to the lower surface.
Figure 21 shows a second scanning unit 2130 according to another embodiment of the invention.
The second scanning unit 2130 includes a second image detector 2131 and a second optical element 2132, for directing light from the lower zone, the lower bevel zone and the apex zone to the second image detector 2131.
The second image detector 2131 is vertical and is parallel to the apex area and to an outer surface 2137 of the second optical element 2132.
The second optical element 2132 comprises a first segment which is directed to the lower zone, a second segment 2134 which is directed towards the lower bevel zone and a third segment 2135 which is directed towards the crown zone.
Each of the first, second and third segments 2131, 2134 and 2135 includes an internal facet that is parallel to an outer facet of that segment.
The second optical element 2132 also includes two outer facets 2136 and 2137 which are oriented with respect to the internal facets.
Figure 21 shows a first outer facet 2137 as being parallel to the top and a second outer facet 2136 as being parallel to the lower bevel area.
The second optical element 2132 also includes two additional outer facets 2138 and 2139. The third outer facet 2138 is parallel to the lower facet and is directed to the dark-bottom illumination unit.
In addition, the second optical element 2132 also includes a first beam splitter 2151 and a second beam splitter 2152. The first beam splitter 2151 is disposed at the lower right zone of the second optical element 2132. The second beam splitter 2152 is disposed at the upper right zone of the second optical element 2132.
Figure 21 also shows an illumination module for directing a light through the second optical element and to the lower zone, the lower bevel zone and the crown zone.
The illumination module comprises a light-field illumination unit 2141 and two dark-field illumination units 2142 and 2143.
The brightfield illumination unit 2141 directs a light through a first beam splitter 2151 to a lower bevel zone. Light from the lower bevel region is directed by the first beam splitter 2151 to a second image detector 2131.
The first darkfield illumination unit 2143 directs light through the second beam splitter 2152 to the apex area. The first dark-field illumination unit 2143 is positioned above the second optical element 2132 and directs its light through a vertical path to a second outer facet 2138 of the second optical element 2132.
The second darkfield illumination unit 2142 is positioned below the second optical element 2132 and directs its light through a first segment and to the lower area.
In the above description (associated with Figures 17 to 21), the illumination units were described as illuminating one or more areas of the border. It should be noted that each illumination unit can also illuminate one or more additional zones. For example, light from the brightfield illumination unit 1739 of Figure 18 may illuminate a portion of the crown area and / or a portion of the upper area. The same thing applies to light collection.
Figure 22 shows a border of an inspected object 1701 and two image detectors 2201 and 2202 according to one embodiment of the invention.
The first image detector 2201 may belong to a first scanning unit 1730 while the second image detector 2202 may belong to a second scanning unit 1740.
For the sake of clarity of description, various components have been omitted in FIG. 22. These components may include optical elements, illumination units and the like.
The first image detector 2201 is parallel to a first imaginary axis 2211 that extends between a lower point 2233 of the apex zone 2243 and between an upper zone point 2231 disposed at the upper zone 2241. The angle between the upper zone 2241 and the first imaginary axis 2211 is smaller than the angle between the upper bevel zone 2242 and the upper zone 2245. In other words, the first imaginary axis 2211 is less inclined than the upper bevel zone 2242.
The second image detector 2202 is parallel to the second imaginary axis 2212 which extends between an upper point 2232 of the crown region 2243 and between a point of the lower zone 2234 disposed at the lower zone 2245. The angle between the lower zone 2245 and the imaginary second axis 2212 is smaller than the angle between the lower bevel zone 2244 and the lower zone 2245. In other words, the imaginary second axis 2212 is less inclined than the lower bevel zone 2242.
This arrangement allows the first and second image detectors 2201 and 2202 to obtain light from multiple areas simultaneously even without optical elements such as the first and second optical elements of the preceding figures.
Figure 23 shows a calibration unit 2310 according to one embodiment of the invention.
The calibration unit 2310 includes three distance sensors 2311, 2312, and 2313, each of which can detect the distance and / or orientation of an area of the border of the inspected object 2301. A higher distance sensor 2311 detects a distance from the upper zone. An intermediate distance sensor 2312 detects a distance from the crown area. A lower distance sensor 2313 detects a distance from the lower zone.
It should be noted that each of these sensors can measure the distance or orientation (or both the distance and the orientation) of one or more areas of the border of the inspected object 1701.
Figure 24 shows an examination unit 2400 according to an embodiment of the invention.
The examination unit 2400 is coupled to a processing unit 2460. The processing unit 2460 receives images from either one of the image detectors of the first and second scanning units (shown in FIG. any one of Figures 17 to 23) and is configured to analyze images obtained by at least one of the first and second image sensors to search for suspected slice defects. A processing unit 2460 locates suspected defects, sends the examination unit 2400 information relating to these suspected defects (such as a location), and the examination unit 2400 acquires images of these suspected defects.
The examination unit 2400 includes an examination camera for obtaining images of suspected defects, a brightfield illumination unit 2440, darkfield illumination units 2420 and an optics 2430 for directing a light toward the border of the inspected object 1701 and coming from the border of the inspected object.
The optical element may be a first optical element such as the optical element shown in Figures 18 or 20.
Conveniently, the examination unit 2400 includes a rotation module 2470 that rotates the examination camera and, in addition or alternatively, the optics 2430 about an axis so as to change an angle between the Examination camera and the border of the object inspected 1701.
Figure 25 shows a second examination unit 2500 according to one embodiment of the invention.
The second examination unit 2500 comprises a second examination camera 2501 and a second optical element 2510 for directing light from the upper area, the upper bevel area and the apex area to the second examination camera 2501. .
The second optical element 2510 includes a first segment which is directed to the upper area, a second segment which is directed to the upper bevel area and a third segment which is directed to the top area. Each of the first, second and third segments comprises an internal facet that is parallel to an outer facet of that segment.
The second segment and the second examination camera 2501 are substantially parallel to the upper bevel area.
Figure 25 also shows two dark background illumination units 2520 and 2530.
The first darkfield illumination unit 2520 directs light through the first segment of the first optical element 2510 and to the upper zone and the upper bevel zone.
The second darkfield illumination unit 2530 directs a light through the third segment and toward the summit area.
Figure 26 shows a first examination unit 2600 according to an embodiment of the invention.
The first examination unit 2600 includes a first examination camera 2601 and a first optical element 2610 for directing light from the upper area, the upper bevel area, and the apex area to the first examination camera 2601. .
The first optical element 2610 includes a first segment that is directed to the upper area, a second segment that is directed to the upper bevel area, and a third segment that is directed to the top area. Each of the first, second and third segments comprises an internal facet that is parallel to an outer facet of that segment.
The second segment and the first examination camera 2601 are substantially parallel to the lower bevel area.
Figure 26 also shows two dark background illumination units 2620 and 2630.
The first darkfield illumination unit 2620 directs a light through the first segment of the first optical element 2610 and to the lower zone and the lower bevel zone.
The second darkfield illumination unit 2630 directs a light through the third segment and toward the summit area.
Figure 27 shows an inspection method 2700 according to one embodiment of the invention.
The method 700 begins with a step 2710 of supporting and rotating an inspected object that includes a border that includes an upper zone, an upper bevel zone, a vertex zone, a lower bevel zone and a lower area.
Step 2710 is followed by steps 2720, 2730 and 2750.
Step 2720 includes illuminating the border of the inspected object.
Step 2730 includes directing, by a first optical element, light from the upper area, the upper bevel area, and the apex area to a first image sensor.
Step 2730 is followed by a step 2740 of simultaneously obtaining, by the first image sensor, images of the upper area, the upper bevel area and the top area.
Step 2750 includes directing, by a second optical element, light from the lower region, the lower bevel region, and the apex region to a second image sensor.
Step 2750 is followed by a step 2760 of simultaneously obtaining, by the second image sensor, images of the lower zone, the lower bevel zone and the vertex zone.
Step 2730 may comprise at least one of the following steps or a combination thereof: (i) directing a light through the first optical element that includes a first segment that is directed to the upper area, a second segment which is directed to the upper bevel area and a third segment which is directed to the apex area, (ii) directing light through a first optical element which includes a second segment, the second segment and the first image sensor being substantially parallel to the upper bevel region; (iii) directing a light through the first optical element and toward the upper zone, the upper bevel zone and the summit zone; (iv) directing a light through the first segment of the first optical element to the upper zone and the upper bevel zone; (v) directing light through a first optical element that includes first, second, and third segments, each of the first, second, and third segments including an internal facet that is parallel to an outer facet of the segment; (vi) directing a light through the first optical element that includes a first internal facet that is directed to the upper area, a second internal facet that is directed to the upper bevel area, a third internal facet that is directed to the apex area, a first outer facet and a second outer facet, the first and second outer facets being oriented relative to the first, second and third internal facets; (vii) directing light through a first optical element that includes first and second outer facets, the first image sensor being directed to an outer facet of the first and second outer facets of the first optical element; (viii) directing light through a first optical element that includes at least one beam splitter; (ix) directing a light to the first beam splitter and to the upper bevel zone; the first beam splitter being arranged to direct light from the upper bevel region to the first image sensor.
The method 2700 may also include a step 2770 of determining a position of the border of the inspected object and sending location signals to motors that are arranged to move at least one of the first and second sensors of the inspected object. image according to the location signals.
The method 2700 may also include a step 2780 of analyzing images obtained by at least one of the first and second image sensors for suspected slice defects, and a step 2790 of obtaining images of the suspected defects by a examination unit.
Step 2790 may be preceded or followed by a step 2795 of rotating the examination camera about an axis to change an angle between the examination camera and the border of the inspected object.
Fig. 28 shows an inspection method 2800 according to an embodiment of the invention.
Method 2800 begins with a step 2810 for supporting and rotating an inspected object that includes a border that includes an upper zone, an upper bevel zone, a vertex zone, a lower bevel zone, and a lower zone. The upper bevel zone is oriented at a higher bevel angle with respect to the upper zone. The lower bevel zone is oriented at a lower bevel angle with respect to the lower zone.
Step 2810 is followed by steps 2820, 2830 and 2840.
Step 2820 includes illuminating the border of the inspected object.
Step 283 includes imaging of the upper bevel area and the upper area by a first image sensor. The first image sensor is oriented at a first image sensor angle with respect to the upper region, the first image sensor angle being smaller than the upper bevel angle.
Step 244 includes imaging of the lower bevel region and the lower region by a second image sensor. The second image sensor is oriented at a second image sensor angle with respect to the lower region, the second image sensor angle being smaller than the lower bevel angle.
The second image sensor angle may be half of the lower bevel angle.
Figure 29 shows an inspection system 2900 and an inspected object 2910 according to an embodiment of the invention.
The inspected object 2910 is supported by a plate 2920 which rotates the inspected object 2910 around a center of the inspected object 2910.
The system 2900 includes a camera 2930 which is positioned above the inspected object 2910 and includes a sensing surface 2931 which is directed to an upper portion of a multifaceted reflector 2950 which directs to the sensing surface 2931 a light from various facets of the border of the inspected object 2910. A 2940 objective lens is positioned between the camera 2930 and the multi-faceted reflector 2950.
Different facets of the multi-faceted reflector 2950 are directed to different areas of the border of the inspected object 2910. Figure 29 shows the multi-faceted reflector 2950 partially surrounding the border of the inspected object 2910.
Figure 29 shows the camera 2930 as having an optical axis 2990 which is parallel to the inspected object 2910 (towards the upper surface of the inspected object 2910) but this is not necessarily the case and the optical axis 2910 can be oriented with respect to an upper surface of the inspected object.
The system 2900 can hold the inspected object 2910 stationary while the object is rotated about its center. Note that the 2900 system or any of its components (2930 camera, 2950 objective lens, 2950 multi-faceted reflector) can move slightly (for example, along the x-axis), by example, for debugging purposes - to compensate for differences in the location of the border of the inspected object.
Figure 29 shows a system comprising two scattering light sources 2960 and 2980 and a reflection illumination light source 2970 but fewer light sources, additional light sources or other light sources can be used. Fig. 29 shows a light source 2960 directed to an upper bevel area of the border of the inspected object 2910, a light source 2980 directed to a lower bevel area of the border of the inspected object 2910, and a source of light 2970 directed towards the top region of the border of the inspected object 2910. It should be noted that any of these light sources can be positioned in a different position.
It should be noted that the multifaceted reflector 2950 can be replaced by a single optical element which can direct light from at least one of the upper bevel zone, the vertex zone or the upper zone. The single optical element may be a prism, a mirror, a reflector, a deflector and the like.
Figures 30 and 31 are a side view and a top view of a system 3000 and an inspected object 3010 according to an embodiment of the invention.
Figure 30 shows various optical components 3030, 3040, 3050, 3060, 3070, 3080 and 3090 of the system 3000 while Figure 31 shows a mechanical element 3003 and an optical head 3005. The optical head 3005 is connected to a mechanical element 3003 Both (3003 and 3005) are rotated (by a rotatable member not shown in Figures 30 and 31) about an axis 3031 while the inspected object 3010 is still held stationary. The optical head 3005 may also be slightly moved for autofocus purposes, in particular for compensating for deviations in the location of the border of the inspected object 3010.
The optical components include a camera 3040 which is positioned above the center of the inspected object 3010 (although it can be positioned anywhere else) and is shown as having an optical axis 3031 which is perpendicular to the upper surface of the inspected object 3010. The camera 3040 receives light through a 3030 objective lens from a 90 degree mirror 3090 which converts a horizontally propagating light (which propagates along an axis optical 3032) in vertically propagating light. It should be noted that the mirror 3090 may reflect light at an angle other than 90 degrees and that the optical axes 3032 and 3031 may deviate from those shown in FIG.
The mirror 3090 receives light from a multifaceted reflector 3050 which directs it to the mirror 3090 from various facets of the border of the inspected object 3010. Different facets of the multifaceted reflector 3050 are directed to different areas. the border of the inspected object 3010. Figure 30 shows the multi-faceted reflector 3050 partially surrounding the border of the inspected object 3010.
Fig. 30 shows a system comprising two scattering light sources 3060 and 3080 and a reflection light source 3070 but fewer light sources, additional light sources or other light sources can to be used. Fig. 30 shows a light source 3060 directed to an upper bevel area of the border of the inspected object 3010, a light source 3080 directed to a lower bevel area of the border of the inspected object 3010, and a source 3070 light directed towards the vertex area of the border of the inspected object 3010. It should be noted that any such light sources can be positioned in a different position.
It should be noted that the multi-faceted reflector 3050 can be replaced by a single optical element that can direct light from at least one of the upper bevel zone, the vertex zone or the upper zone. The single optical element may be a prism, a mirror, a reflector, a deflector and the like.
It should be noted that the mirror 3090 and the multi-faceted reflector 3050 can be rotated while the camera 3040 and the objective lens 3030 remain fixed.
Figure 30 shows a rotating device 377 which is connected to the system 3000 to show that one or more components of the system 3000 can be rotated. The rotation device 3737 can be connected to the diversity of optical components by mechanical elements (not shown) which are known in the state of the art.
It should be noted that the illumination light sources (such as the illumination light sources 3060, 3070 and 3080) can be replaced by illumination elements which are positioned above the mirror 3090 and which direct a light. light to the mirror 3090, while the mirror 3090 directs the light to the multi-faceted reflector 3050 and to the edge of the inspected element. Such sources of illumination light may have an optical axis which is the same as the optical axis 3031, which deviates slightly from the optical axis 3031 or even which is parallel to the optical axis 3031. They can provide illumination coax without preventing the camera 3040 from forming images of the border of the inspected object. This can be achieved by using a beam splitter, using optical fibers or other elements that can surround the camera and form a ring of light or other illumination such as light-field illumination. .
Figure 32 shows an inspection method 3200 according to an embodiment of the invention.
The method 3200 begins with a step 3210 of supporting and rotating an inspected object that includes a border that includes an upper zone, an upper bevel zone, a vertex zone, a lower bevel zone, and a lower zone. . The inspected object can be rotated around its center.
Step 3210 is implemented in parallel with steps 3220, 3230 and 3240.
Step 3220 includes illuminating the border of the inspected object.
Step 3230 comprises the direction, by a multifaceted element, of light from the upper zone, the upper bevel zone, the lower zone, the lower bevel zone and the vertex zone towards a camera which is disposed above the inspected object and which may have an optical axis which is parallel to the upper surface of the inspected object. The camera includes a sensing surface that faces the upper portion of the multi-faceted element. Step 3230 may include any steps, including step 2730 of Figure 27.
Step 3240 includes simultaneously obtaining, by the camera, images of the upper zone, the upper bevel zone, the lower zone, the lower bevel zone and the crown zone.
The method 3200 may also include various steps that may be equivalent to (i) step 2770 of determining a position of the border of the inspected object and sending location signals to engines that are arranged to move to at least one of first and second image detectors as a function of the location signals; (ii) step 2780 of analyzing images obtained by at least one of the first and second image sensors to search for suspected slice defects and (iii) step 2790 of obtaining images of suspected defects by an examination unit.
Figure 33 shows an inspection method 3300 according to an embodiment of the invention.
Process 3300 begins with steps 3310 and 3333.
Step 3310 includes supporting an inspected object that includes a border that includes an upper zone, an upper bevel zone, a vertex zone, a lower bevel zone, and a lower zone. The inspected object can be rotated about its axis.
Step 3333 includes rotating illuminating components and collection components (including a camera) to scan the border of the inspected object 3333.
Steps 3310 and 3333 can be implemented in parallel with steps 3320, 3330 and 3340.
Step 3320 includes illuminating the border of the inspected object.
Step 3330 comprises the direction, by a multifaceted element, of light from the upper zone, the upper bevel zone, the lower zone, the lower bevel zone and the mirror vertex zone and the directing light from the mirror to a camera that is disposed above the inspected object that may have an optical axis that is perpendicular to the upper surface of the inspected object. The mirror can introduce a 90 degree shift in the light propagation axis.
Step 3330 may include any steps, including step 2730 of Figure 27.
Step 3340 includes simultaneously obtaining, by the camera, images of the upper zone, the upper bevel zone, the lower zone, the lower bevel zone and the crown zone.
The method 3300 may also include various steps that may be equivalent to (i): step 2770 of determining a position of the border of the inspected object and sending location signals to motors that are arranged to move at least one of the first and second image sensors according to the location signals; (ii) step 2780 of analyzing images obtained by at least one of the first and second image sensors for suspected slice defects and (iii) step 2790 of obtaining images of defects suspected by an examination unit.
It should be noted that any of the multi-faceted reflectors mentioned above may also allow light to propagate through it.
The present invention can be practiced using conventional tools, methodologies, and components. Therefore, the details of these tools, components and methodologies are not detailed here. However, it should be recognized that the present invention can be practiced without resorting to the specifically disclosed details.
Only exemplary embodiments of the invention and only some examples of its versatility are shown and described in this application. It should be understood that the present invention is suitable for use in a variety of other combinations and environments and is capable of being changed or modified within the scope of the inventive concept as expressed in the application.

权利要求:
Claims (19)
[1]
An optical inspection system, characterized in that it comprises: - a first image detector (1731); A second image detector (1941); A support module (1702) for supporting and rotating an inspected object (100) that includes a border (160) that includes an upper area (110), an upper bevel area (120), a top area ( 13 0), a lower bevel zone (140) and a lower zone (150); A first optical element (1732) for directing light from the upper region (110), the upper bevel region (120) and the apex area (130) to the first image detector (1731); and - a second optical element (1942) for directing light from the lower region (150), the lower bevel region (140) and the vertex region (130) to the second image detector (1941).
[2]
2. System according to claim 1, characterized in that the first optical element (1732) comprises a first segment (1733) which is directed towards the upper zone (110), a second segment (1734) which is directed towards the zone upper bevel (12 0) and a third segment (1735) which is directed to the apex area (130).
[3]
3. System according to claim 1, characterized in that it further comprises an illumination module (1736) for directing a light through the first optical element (1732) and to the upper zone (110), the zone upper bevel (120) and the top region (130).
[4]
4. System according to claim 3, characterized in that the illumination module (1736) comprises a dark background illumination unit (1737, 1738).
[5]
5. System according to claim 1, characterized in that it comprises a light-field illumination unit (1739).
[6]
6. System according to claim 1, characterized in that it further comprises a calibration unit (1710) for determining a position of the border (160) of the inspected object and for sending location signals to motors which are arranged to move at least one of the first and second image sensors (1731, 1941) according to the location signals.
[7]
7. System according to claim 1, characterized in that it further comprises: a processing unit for analyzing images obtained by at least one of the first and second image detectors (1731, 1941) for searching suspected slice defects; and an examination unit (1720, 2400) which includes an examination camera for obtaining images of suspected defects.
[8]
8. System according to claim 7, characterized in that the examination unit (2400) comprises a rotation module which rotates the examination camera (2420) around an axis so as to change an angle between the examination camera (2420) and the border of the inspected object.
[9]
9. Inspection method (2700), characterized in that the inspection method comprises: - the support and the rotation of an inspected object which comprises a border which comprises an upper zone, a zone of upper bevel, a crown zone, a lower bevel zone and a lower zone (2710); - illumination of the border of the inspected object (2720); Simultaneously obtaining, by the first image detector, images of the upper zone, the upper bevel zone and the summit zone (2740); and simultaneously obtaining, by the second image detector, images of the lower zone, the lower bevel zone and the summit zone (2760).
[10]
The method (2700) according to claim 9, characterized in that it comprises directing a light through the first optical element which includes a first segment which is directed to the upper area, a second segment which is directed to the upper bevel area and a third segment that is directed to the summit area (2730).
[11]
11. Method (2700) according to claim 9, characterized in that the first optical element further comprises a second beam splitter.
[12]
12. Method (2700) according to claim 9, characterized in that it further comprises: - determining a position of the border of the inspected object (2770); and sending location signals to motors that are arranged to move at least one of the first and second image sensors according to the location signals (2770).
[13]
Method (2700) according to claim 9, characterized in that it further comprises: - analyzing the images obtained by at least one of the first and second image sensors to search for suspected slice defects (2780); and obtaining images of defects suspected by an examination unit (2790).
[14]
Method (2700) according to claim 9, characterized in that it comprises rotating the examination camera about an axis so as to change an angle between the examination camera and the border of the camera. the inspected object (2795).
[15]
15. Optical inspection system (2900, 3000), characterized in that it comprises: - an image detector (2930, 3040); and - a single optical element (2950, 3050) which at least partially surrounds a border of an inspected object (2910, 3010); the optical element (2950, 3050) being adapted to direct light from different areas of the border of the inspected object (2910, 3010) to the image detector (2930, 3040), so that the detector image (2930, 3040) simultaneously obtains images of the different areas; The image detector (2930, 3040) being disposed above the inspected object (2910, 3010) and having an optical axis which is substantially parallel to an upper surface of the inspected object; - the image detector (2930, 3040) having a detection surface (2931) which is directed towards an upper part of the single optical element (2950, 3050); the system further comprising a platen (2920) which rotates the inspected object (2910, 3010) around a center of the inspected object.
[16]
System according to claim 15, characterized in that the single optical element (2950, 3050) is a multi-faceted reflector.
[17]
17. System according to claim 15, characterized in that the image detector (3040) and a mirror (3090) are disposed above the inspected object (3010); the image detector (3040) including a detection surface that is directed to the mirror (3090), and an upper portion of the single optical element facing the mirror; the system comprising a rotation device for rotating at least the mirror and the single optical element with respect to the inspected object so as to scan the edge of the inspected object.
[18]
18. A method of inspecting a border of an inspected object, characterized in that it comprises: the illumination of the border of the inspected object; and - directing light from different areas of the border of the inspected object to an image detector, by a single optical element, which at least partially surrounds a border of an inspected object, to the detector of the object. 'picture ; - rotating at least the single optical element and a mirror which is disposed above the inspected object while simultaneously obtaining images of the different areas by an image sensor which comprises a surface of detection which is directed towards the mirror, an upper part of the multifaceted reflector being directed towards the mirror.
[19]
19. The method of claim 18, characterized in that it comprises simultaneously obtaining, by the image sensor, images of the different areas while the inspected object is rotating around a center of the image. inspected object; the image sensor being disposed above the inspected object and having an optical axis which is substantially parallel to an upper surface of the inspected object; the image detector having a detection surface which is directed towards an upper part of the single optical element.

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法律状态:

优先权:

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申请号 | 申请日 | 专利标题

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US22410109P| true| 2009-07-09|2009-07-09|

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US22410109|2009-07-09|

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