WAFER PROCESSING PROCEDURES

专利摘要:
Disclosed is a wafer processing method for removing an annular reinforcing region, wherein the annular reinforcing region is formed around a wafer component region. The method includes supporting the wafer with an adhesive tape on an annular frame, forming a mark corresponding to a notch at a position radially within a boundary between the reinforcing region and the device region, cutting the boundary portion together with the adhesive tape thereby removing the reinforcing area from the component area and moving the annular reinforcing area supported by the adhesive tape on the annular frame away from a holding table to thereby remove the annular reinforcing area from the wafer.
公开号:AT518580A2
申请号:T50315/2017
申请日:2017-04-18
公开日:2017-11-15
发明作者:
申请人:Disco Corp；
IPC主号:

专利说明:

The invention relates to a general method for removing an annular reinforcing section from a wafer having a component region, wherein the annular reinforcing section is formed around the device region.
More particularly, the invention relates to a method of processing a wafer having a front side, a back side, and an outer periphery, the front side having a component region where a plurality of components are formed, and a peripheral edge region forming the Surrounding part region, wherein the outer periphery has a notch to indicate a crystal orientation, and the back has a circular recess corresponding to the component region, and an annular reinforcing region corresponding to the peripheral edge region
A wafer having a plurality of devices, such as integrated circuits (ICs) and large-scale integrations (LSIs), on the front side is divided into a plurality of individual chips corresponding to the plurality of devices, a so-called. Dicing device or the like. Is used. These chips are widely used to be used in various electronic devices. For the purpose of reducing the size and weight of the electronic device, for example, the thickness of the wafer is reduced to 50 to 100 μm. However, such a thin wafer has a low rigidity and warping may occur. The wafer is thus difficult to handle. To remedy this problem, a method for grinding the backside of the wafer in a central area corresponding to a device area where the devices are formed has been proposed, whereby an annular reinforcing area is formed along the outer periphery of the wafer to increase the rigidity of the wafer increase (see eg JP-Auslegeschrift2007-019461).
There has also been proposed a method of removing the annular reinforcing area of the wafer prior to dividing the wafer along parting lines (see, for example, Japanese Unexamined Patent Publication 2015-147231). In the method described therein, an adhesive tape is attached to the front side of the wafer, and the adhesive tape is supported at its peripheral region on an annular frame, whereby the wafer is supported by the annular frame via the adhesive tape. In this state, a boundary portion between the component area and the annular reinforcing area (peripheral edge area) is cut by laser processing together with the adhesive tape to thereby separate the annular reinforcing area from the component area. Subsequently, the annular reinforcing area is removed from the wafer together with the annular frame.
However, in the wafer processing method disclosed in Japanese Patent Application Laid-Open No. 2015-147231, there is a problem that when the annular reinforcing portion is removed from the wafer, a notch formed on the annular reinforcing portion is also removed from the wafer, so that aligning the wafer in a subsequent step becomes difficult.
It is therefore an object of the invention to provide a wafer processing method in which a suitable wafer is possible even after the removal of the annular reinforcing region from the wafer.
According to an aspect of the present invention, a wafer processing method of processing a wafer having a front side, a back side, and an outer periphery, the front side having a component region where a plurality of components are formed, and a peripheral edge region forming the Surrounding part region, wherein the outer circumference has a notch to indicate a crystal orientation, and the back has a circular recess corresponding to the component region, and an annular reinforcing region corresponding to the peripheral edge region, characterized by a wafer supporting step, with the attachment of the Front side of the wafer on an adhesive tape, which is supported in its peripheral region on an annular frame having an inner side opening in the state in which the wafer is placed in the inner side opening of the annular frame, whereby the wafer by the adhesive tape on the annular Framework is supported en step of separating the annular reinforcing region with holding the wafer on a holding table in the state where the adhesive tape is in contact with the holding table after the wafer supporting step has been performed, and then applying a laser beam having an absorption wavelength to the wafer; whereby a boundary portion between the annular reinforcing portion and the component portion is cut along with the adhesive tape to separate the annular reinforcing portion from the component portion, a step of forming a mark corresponding to the notch at a position radially inward of the boundary portion, before or after Performing the separation of the annular reinforcing region, and a step of removing the annular reinforcing region by moving the annular reinforcing region supported by the adhesive tape on the annular frame away from the holding table after performing the step separating the annular reinforcing region and after the step of marking formation, whereby the annular
Gain area is removed from the wafer.
In this technique, the laser beam is applied along the boundary between the device region and the annular reinforcing region of the wafer to thereby separate the annular reinforcing region from the device region. Thereafter, the annular reinforcing portion is moved away from the holding table to thereby remove the annular reinforcing portion from the wafer. The mark corresponding to the notch formed in the prior art on the outer periphery of the annular reinforcing portion is formed at a position radially inward of the boundary between the component portion and the annular reinforcing portion. Even after removing the annular reinforcing region from the wafer, the label thus remains on the wafer. As a result, the wafer can be properly aligned with respect to the label in place of the notch in the subsequent step.
Preferably, the wafer processing method further comprises a positional relationship between the notch and the mark formed on the wafer by using detecting means after the labeling step has been performed and before the step of separating the annular reinforcing area is performed.
According to the invention, the mark corresponding to the notch formed on the outer periphery of the annular reinforcing portion is formed at a position radially within the boundary between the component portion and the annular reinforcing portion. Thus, even after removing the annular reinforcing area from the wafer, the wafer can be properly aligned in the subsequent step.
An advantageous method is further characterized by a step of detecting a positional relationship between the notch and the mark formed on the wafer by using detecting means after the step of marking formation has been performed and before the step of separating the reinforcing area is carried out. The invention will be explained nachfoldend using exemplary embodiments and with reference to the drawings. 1 shows a perspective view of a
A laser processing apparatus for carrying out a wafer processing method according to a preferred embodiment of the invention,
FIG. 2 is a schematic cross-sectional view of a wafer and a holding table included in the laser processing apparatus shown in FIG.
Figure 3 is a schematic cross-sectional view showing a
Wafer supporting step illustrates
FIG. 4A is a schematic cross-sectional view illustrating an imaging process at an identification step;
FIG. 4B is a schematic plan view showing a marking operation in the labeling step;
FIG. 4C is a schematic cross-sectional view illustrating the marking process;
FIG. 5 is a schematic cross-sectional view illustrating the step of separating the annular reinforcing area.
Figure 6 is a schematic cross-sectional view illustrating the removal of the annular reinforcing area, and
Figure 7 is a schematic plan view illustrating the step of detecting a positional relationship.
A wafer processing according to a preferred embodiment of the invention will now be described with reference to the accompanying drawings.
Figure 1 shows in a perspective view a laser processing apparatus 1, the configuration of which - as shown in Figure 1 is merely exemplary, wherein other configurations when performing the wafer processing can also be used.
In the figure, the laser processing apparatus 1 has a laser device 40 for applying a laser beam to a wafer W held on a holding table 30, with the laser device 40 and the holding table 30 relatively moved to process the wafer W. A plurality of crossing dividing lines (not shown) are mounted on the front side of the wafer W to thereby define a plurality of separate regions in which a plurality of components (not shown) are formed. The front side of the wafer W generally has a component area Al in which the components are formed and a peripheral edge area A2 which surrounds the component area Al. Further, the outer periphery of the wafer W is provided with a notch N (see Fig. 4B) indicating crystal orientation.
As shown in FIG. 2, on the back surface (upper surface in FIG. 2) of the wafer W, a circular recess 70 is formed in a central area corresponding to the component area Al to thereby form a protruding annular reinforcing area 71 around the annular recess 70 on the surface Forming back of the wafer W in a peripheral region corresponding to the edge region A2. The circular recess 70 is formed by grinding the back side of the wafer W.
The wafer W may be called TAIKO wafer. Reference numeral 73 denotes a boundary area between the component area
Al and the annular reinforcing portion 71 (the peripheral edge portion A2). Since the thickness of the wafer W is small only in the device area Al, the rigidity of the wafer W is increased by the annular reinforcing region 71 formed around the device area Al. Therefore, although the rigidity of the wafer W in the device area Al is low due to its reduced thickness, the annular reinforcing area 71 can compensate for a lack of rigidity, thereby eliminating warpage of the wafer W and preventing damage to the wafer W upon transferring the wafer W. The wafer W may be a semiconductor wafer formed on silicon or gallium arsenide, for example, or may be an optical component wafer formed of, for example, ceramic, glass, or sapphire.
An adhesive tape T is attached to the central portion on the front side of the wafer W, and the annular frame F is attached to the peripheral portion of the adhesive tape T. After the wafer W having the annular reinforcing portion 71 has been subjected to the predetermined processing, the annular reinforcing portion 71 is removed by the laser processing apparatus 1. Compared with the mechanical dicing using a cutting blade, the laser processing has an advantage in that the laser beam does not interfere with the annular reinforcing region 71 when removing this reinforcing region 71 from the wafer W. The predetermined processing is a processing for the wafer W already having the annular reinforcing region 71. This processing includes, for example, forming a reflection film on the back side of the wafer W in the device area Al.
According to Figure 1, the laser processing apparatus 1 has a base 10 and a holding table moving mechanism 20, which is based on 10 for moving the holding table 30 in the X direction, which is shown by the arrow X, and in the Y direction by the arrow Y is shown, is provided. The holding table moving mechanism 20 has a pair of parallel guide rails 21 provided on the base 10 and extending in the X direction, and a motor-driven X table 22 slidably mounted on the guide rails 21. The holding table moving mechanism 20 further includes a pair of parallel guide rails 23 provided on the upper surface of the X table 22 so as to extend in the Y direction, and a motor-driven Y table 24 slidably disposed on the Y table Guide rails 23 is mounted.
A groove portion (not shown) is formed on the lower surface of the X table 22, and a ball screw 25 is threadedly engaged with the groove portion of the X table 22. A motor 27 for driving the X table 22 is connected to one end of the ball screw 25 connected. Therefore, when the motor 27 is operated, the ball screw 25 is rotated, whereby the X table 22 is moved along the guide rails 21 in the X direction. Similarly, a groove portion (not shown) is formed on the lower surface of the Y table 24, and a ball screw 26 is threadedly engaged with the groove portion of the Y table 24. A motor 28 for driving the Y table 24 is connected to one end of the Y table 24 Ball screw 26 connected. When the motor 28 is operated, the ball screw 26 is rotated, whereby the Y table 24 is moved along the guide rails 23 in the Y direction. As a result, the holding table 30 can be moved along the guide rails 21 both in the X direction along the guide rails 21 and in the Y direction. The holding table 30 is mounted on the Y table 24 so as to be rotatable about a vertical axis extending in the Z direction, shown by an arrow Z. The holding table 30 has an upper surface as a holding surface 31 for holding the wafer W. A plurality of clamps 32 for clamping the annular frame F carrying the wafer B through the adhesive tape T are provided on the outer circumference of the holding table 30.
A vertical wall 11 is formed at the rear end of the base 10 on the rear side of the holding table 30. An arm portion 12 protrudes from the front surface of the vertical wall 11. The laser device 40 is at the front end of the
Arm portion 12 provided such that it is vertically opposite the holding table 30. The laser device 40 has a laser head 41 for applying the laser beam to the wafer W, which is held on the holding table 30. The laser beam is therefore oscillated by an oscillator (not shown) and then focused on the holding table 30 by focusing means (not shown) to the wafer W. The laser beam has an absorption wavelength to the wafer W such that a part of the wafer W is sublimated by the application of the laser beam to the wafer W, that is, laser ablation is performed.
As used herein, the term "ablation" means that as the intensity of the applied laser beam becomes greater than a predetermined processing threshold, the energy of the laser beam is converted into electronic, thermal, photo-scientific, and mechanical energy the surface of a solid is converted such that neutral atoms, molecules, positive and negative ions,
Radicals, clusters, electrons and light are released explosively and the solid surface is etched.
Imaging means 45 for imaging the outer peripheral edge 72 (see FIG. 4B) of the wafer W are disposed near the laser device 40. The outer peripheral edge 72 of the wafer W is imaged at three arbitrary positions by the imaging means 45. Everybody through the
Imaging means 45 is subjected to various image processing to detect the coordinates of these three positions on the outer peripheral edge 72. Subsequently, the center of the wafer W relative to the coordinates at these three positions on the outer peripheral edge 72 is calculated, and the laser head 41 is aligned relative to this center of the wafer W. By performing this alignment, the laser head 41 can be precisely positioned directly above the boundary region 73 between the device region Al and the annular reinforcing region 71 (the edge region A2).
The laser processing apparatus 1 further comprises control means 50 for centrally controlling all components. The control means 50 comprises a processor for performing various processing and a memory connected to the processor. The memory consists of one or more storage media, such as, depending on uses, a read-only memory (ROM) and a random access memory (RAM). The ROM of the control means 50 prestores a program to be executed by the processor in performing various processings in the steps to be described below. The laser processing apparatus 1 performs the laser processing along the boundary region 73 between the device region Al and the annular reinforcing region 71 to thereby separate the annular reinforcing region 71 from the device region Al.
In the case where a reflection foil made of metal is formed on the back side of the wafer W in the device area Al, the pattern on the front side of the wafer W can not be seen from the back side of the wafer W by using an infrared (IR) camera or the like so that the direction of the wafer W can not be detected. The notch N for aligning is thus formed on the outer circumference of the wafer as well as allowing the recognition of the direction of the wafer W also from its back side. After the removal of the annular reinforcing region 71 from the wafer W, however, the notch N is on the annular one
Reinforcing portion 71 was formed, no longer present, so that the wafer W can not be aligned relative to the notch N in the subsequent step.
To remedy this problem, a mark M corresponding to the notch N is formed radially inside the boundary region 73 between the device region Al and the annular reinforcing region 71 before separating the annular reinforcing region 71 from the device region Al (see Figure 4C). Thus, even after the removal of the annular reinforcing region 71 from the wafer W, the wafer W can be properly aligned in the subsequent step relative to the marker M. The direction of the wafer W can therefore be recognized with reference to the label M.
The holding table 30 used in carrying out the wafer processing method will now be described in more detail with reference to FIG. Figure 2 is a schematic cross-sectional view of the wafer W and the holding table 30 in this preferred embodiment. The configuration of the holding table 30 shown in Fig. 2 is purely illustrative, and it can be appropriately changed within the scope of the invention.
As shown in Fig. 2, the upper surface of the holding table 30 is provided with an annular discharge groove 33 for letting out a laser beam in carrying out the ablation. The exit groove 33 is formed along the outer circumference of the holding table 30 so as to correspond to the boundary area 73 between the device area Al and the annular reinforcing area 71 of the wafer W. A central portion of the upper surface of the holding table 30, radially inside the discharge groove 33, is formed as a holding surface 31 for holding the wafer W and corresponds to the device area Al of the wafer W. The holding surface 31 of the holding table 30 is connected to a pair of orthogonal suction grooves 34 (see FIG 1), which intersect at the center of the holding surface 31, and a plurality of concentric suction grooves 35 formed around the interface of the suction grooves 34.
The suction grooves 34 and 35 are connected to a vacuum source (not shown) through a suction passage (suction joint) (not shown) formed in the holding table 30. A vacuum generated by the vacuum source is thus applied to the suction grooves 34 and 35, whereby the wafer W is held on the holding surface 31 by the adhesive tape T. Further, a peripheral portion of the upper surface of the holding table 30, radially outside the discharge groove 33, is formed as an annular support surface 36. The support surface 36 is flush with the support surface 31 and corresponds to an angular range of the adhesive tape T between the wafer W and the annular frame F. The adhesive tape T is thus held horizontally on the support surface 31 and the support surface 36, and the annular reinforcement portion 71 is prevented to fall into the discharge groove 33.
The discharge groove 33 has an inclined bottom 37, the depth of which increases toward the center of the holding table 30. The inclined bottom 37 of the discharge groove 33 is formed with fine roughness for scattering the laser beam. The fine roughness can be formed, for example, by sandblasting. Thanks to the inclination of the inclined bottom 37, the laser beam reflected from the inclined bottom 37 is deflected by the light source (laser head 41). The laser beam is further scattered by the fine roughness formed on the inclined bottom 37, so that the intensity of the laser beam reflected from the inclined bottom 37 is reduced, thereby causing damage to the light source due to the reflected light to prevent. Further, even when imaging the wafer W by using the imaging means 45 (see Fig. 4A), the imaging light emitted from the imaging means 45 and reflected from the inclined bottom 37 is deflected by the imaging means 45 due to the inclination of the inclined bottom 37, and the strength of the reflected imaging light is also reduced by the fine roughness of the sloping bottom 37. As a result, a high contrast in an image showing the outer peripheral edge 72 of the wafer W as obtained by the imaging means 45 can be achieved.
The wafer processing method according to the preferred embodiment will now be described in more detail with reference to Figs. Fig. 3 shows a wafer supporting step, Figs. 4A to 4C show an identifying step, Fig. 5 shows a step of separating the annular reinforcing area, Fig. 6 shows a step of removing the annular reinforcing area, and Fig. 7 shows a position detecting step. The following wafer processing method is merely illustrative and can be changed appropriately. FIG. 4A shows an imaging process for the wafer W, and FIGS. 4B and 4C show an identification process for the wafer W.
As shown in Fig. 3, the wafer supporting step is first carried out in the following manner. In the wafer supporting step, the wafer W is set in the inner side opening Fa of the annular frame F, and the adhesive tape T is attached to the front side (lower surface) of the wafer W and to one side (lower surface) of the annular frame F. The wafer W is thus supported by the adhesive tape T on the annular frame 11 in the state where the annular reinforcing portion 71 is directed upward. Thereafter, the wafer W, which is held by the adhesive tape T on the annular frame F, is transferred to the laser device 1 (see Fig. 1). The wafer supporting step may be performed manually by an operator, or may be performed by an adhesive tape mounter (not shown).
After executing the wafer supporting step shown in Fig. 3, the image forming process is performed in the label formation as shown in Fig. 4A.
In the image forming process of Fig. 4A, the wafer W is held by the adhesive tape T on the holding table 30 of the laser device 1 (see Fig. 1) in the state where the annular reinforcing portion 21 faces upward, and the annular frame F is moved through the Clamps 32 attached. Thereafter, the holding table 30 is appropriately moved to position the annular verse portion 71 of the wafer W directly below the imaging means 45. At this time, imaging light will be from the
Imaging means 45 applied to the outer peripheral edge 42 of the wafer W and to its peripheral region. The applied imaging light is reflected from the outer peripheral edge 72 and its periphery, and then sent back to the imaging means 45, thereby obtaining an image.
As shown in Figure 4A, the annular reinforcing region 71 has a horizontal upper surface 76 radially inward of the outer peripheral edge 72. The illuminating light applied by the imaging means 45 is reflected on the upper surface 76 of the annular reinforcing region 71 to cause halation cause. The reflected light from the outer peripheral edge 72 and the upper surface 76 of the annular reinforcing region 71 is captured by the imaging means 45. On the other hand, the exit groove 33 is radially outward of the outer peripheral edge 72. The imaging light applied by the imaging means 45 is thus transmitted through the adhesive tape T and then reflected on the inclined bottom 37 of the exit groove 33. The reflected light from the inclined bottom 37 is guided to the center of the wafer W and also scattered by the fine roughness on the inclined bottom 37. The reflected light from the inclined bottom 37 and the exit groove 33, the radially outside of the outer
Peripheral edge 72 is present, is therefore hardly collected by the imaging means 45.
The image of the outer peripheral edge 72 and its periphery, a portion of the image corresponding to the upper surface 76 that is radially within the outer peripheral edge 72, is considered to be a bright region because the light reflected from the upper surface 76 from the imaging means 45 is caught while the other portion of the image corresponding to the inclined bottom 37, which is radially outside the outer peripheral edge 72, is seen as a dark portion because the light reflected from the inclined bottom 37 is hardly caught by the imaging means 45. The contrast in the image of the outer peripheral edge 72 and its circumference can thus be high, so that the outer peripheral edge 72 of the wafer W can be reliably recognized. In this manner, the outer peripheral edge 72 of the wafer W is imaged by the imaging means 45 at a plurality of positions (three positions in this preferred embodiment). According to the images at these plural positions on the outer peripheral edge 72, the coordinates of these positions are detected, and the center O (see Fig. 4B) of the wafer W is calculated according to the previously acquired coordinates.
After performing the imaging process shown in Fig. 4A, the labeling process is performed in an identifying step as shown in Fig. 4B.
In the marking process, the mark M (see FIG. 4C) corresponding to the notch N is formed at a position radially inside the boundary portion 73 between the annular reinforcing portion 71 and the component portion A 1, that is, radially within a laser-machined mark 79, to be formed in the subsequent step of separating the annular reinforcing area. More specifically, an identification position P is determined radially equally within the boundary portion 73 so as to lie on a straight line LI connecting the center O and the notch N of the wafer W. This marking position P is set directly under the laser head 41 (see FIG. 4C). The position of the notch N may be detected according to the distance and the direction from the center O of the wafer W as previously stored, or may be detected by the imaging means 45 upon detecting the outer peripheral edge 72.
Thereafter, the focal point of the laser beam to be applied by the laser head 41 is set to a position near the upper surface (back side) of the wafer W. In this state, the laser beam is applied from the laser head 41 at the mark position P set radially inward of the boundary portion 73 between the device area Al and the annular reinforcing area 71 of the wafer W as shown in Fig. 4C. As described above has the
Laser beam has an absorption wavelength to the wafer W, so that the upper surface of the wafer W is partially removed from the laser beam at the identification position P, thereby forming the label M corresponding to the notch N. The laser beam applying laser device 40 having the laser head 41 therefore functions as a marking means for forming the mark M on the upper surface of the wafer W. In a modification, such marking means may also be provided by ink jet means for applying an ink to the upper surface of the wafer W are provided to form a tag.
After carrying out the labeling step shown in Figs. 4A to 4C, the step of separating the annular portion as shown in Fig. 5 is executed. In this separation step, the laser beam having an absorption wavelength with respect to the wafer W is moved from the laser head 41 to the boundary region 73 between the device region Al and the annular reinforcing region 71 in the state where the wafer W is held on the holding table 30 , applied, whereby the boundary region 73 is cut. The annular reinforcing region 71 is therefore separated from the device region Al. More specifically, the holding table 30 is moved right under the laser head 41 to match the position of the boundary region 73. Subsequently, the focal point of the laser beam is adjusted, and the laser beam is then applied from the laser head 41 to the boundary portion 73.
In the state where the laser beam is applied, the holding table 30 is rotated, thereby cutting the boundary area 73 together with the adhesive tape T. The annular reinforcing portion 71 is thus separated from the component portion Al. At this time, the laser beam penetrates into the wafer W and the adhesive tape T and is then reflected on the inclined bottom 37 of the exit groove 33. The light reflected from the inclined bottom 37 is directed to the center of the holding table 30. Further, since the fine roughness is formed on the inclined bottom 37, the laser beam is scattered from the inclined bottom 37 to reduce the intensity. The reflected light from the inclined bottom 37 light is consequently hardly returned to the laser head 41. Even if the laser beam is reflected to the laser head 41, the laser source is not damaged by the reflected light because the intensity is low.
In this way, the boundary region 73 between the device region Al and the annular reinforcing region 72 is cut by the laser beam upon separation of the annular reinforcing region. However, if the width of a cutting groove formed by the laser beam is small, there is a possibility that this cutting groove is filled by waste generated by the abrasion. To remedy this problem, the step of separating the annular reinforcing area may be repeated concentrically to increase the width of the cutting groove intersecting the boundary area 73 between the device area Al and the annular reinforcing area 71. The annular reinforcing region 71 can thus be completely separated from the component region Al.
After carrying out the step of separating the annular reinforcing portion shown in Fig. 5, the step of removing the annular reinforcing portion as shown in Fig. 6 is carried out. Upon removal of the annular reinforcing portion, the clamps 32 clamping the annular frame F are released, and transfer means 60 having a plurality of suction cups 61 are mounted directly above the holding table 30. Subsequently, the suction cups 61 are actuated to hold the annular frame F by suction. Thereafter, the suction cups 61 are lifted to move the annular frame 11, which holds the annular reinforcing portion 71 through the adhesive tape T, vertically away from the holding table 30.
The annular reinforcing region 71 is thus removed from the wafer W, and only the device region Al remains on the holding table 30.
After removing the annular reinforcing region 71 from the wafer W, it can not be checked whether the
Marking M precise corresponds to notch N In this regard, a step of detecting the positional relationship shown in FIG. 7 may be performed after executing the step of marking formation and before performing the step of separating the annular portion so that the positional relationship between the mark M and the notch N is detected.
Upon detecting the positional relationship, the label M formed on the wafer W is positioned directly below the imaging means 45 (see Fig. 4A), and the label M is imaged by the imaging means 45. Subsequently, the coordinates of the mark M are precisely detected from an image obtained by the imaging means 45. The positional relationship between the mark M and the notch N can therefore be detected precisely.
As a modification, this step may include a step of determining an angle Θ between a straight line LI connecting the center O of the wafer W and the notch N, and a straight line L2 indicating the center O of the wafer W and the mark such as shown in Figure 7 connects. It is thus possible to detect an angular deviation of the orientation of the mark M, as viewed from the center O of the wafer W, from the orientation of the notch N, as seen from the center O of the wafer W. The angular deviation of the
Marking M relative to the notch N or the coordinates of the mark M may be used in aligning the machining means relative to each dividing line (not shown) formed on the wafer W in the subsequent step. The imaging means 45 therefore functions as detecting means for precisely detecting the positional relationship between the mark M and the notch N. As a modification, such detecting means can be provided by any configuration capable of the mark M formed on the wafer W. to recognize.
In the wafer processing method according to this embodiment described above, the laser beam is applied along the boundary region 73 between the device region Al and the annular reinforcing region 71 of the wafer W to thereby separate the annular reinforcing region 71 from the device region Al. Subsequently, the annular reinforcing portion 71 is moved away from the holding table 30 to thereby remove the annular reinforcing portion 71 from the wafer W. The mark M corresponding to the notch N formed on the outer circumference of the annular reinforcing portion 71 is formed at a position radially inward of the boundary portion 73 between the component portion Al and the annular reinforcing portion 71. Even after removing the annular
The gain region 71 of the wafer W leaves the mark M on the wafer W. As a result, the wafer W can be properly aligned with respect to the mark M instead of the score N in the subsequent step.
The invention is not limited to the above preferred embodiment, but various modifications can be made. In the above preferred embodiment, the size, shape, etc., shown in the accompanying drawings are exemplary only, and they can be appropriately changed within the scope in which the effect of the invention can be set forth. Furthermore, various changes may be made without departing from the scope of the subject invention.
For example, although the exit groove 33 in the above preferred embodiment is formed on the upper surface of the holding table 30, the exit groove 33 may not be formed on the upper surface of the holding table 30, provided that the light source of the laser beam is reflected by the reflected light of FIG the upper surface of the holding table is not damaged.
Although, in the above preferred embodiment, the step of marking formation is performed before the step of separating the annular reinforcing area is carried out, the step of marking formation may be carried out even after the step of separating the annular reinforcing area is carried out.
Although the label M is formed at a position radially inside the boundary region 73 between the device region Al and the annular reinforcing region 71 so as to be on the straight line LI, the center O of the wafer W and the notch N in the above preferred embodiment connects, the mark M may be formed at any position corresponding to the notch N radially within the boundary region 73 between the device region Al and the annular reinforcing region 71. For example, the label M may be formed at a position radially inside the boundary region 73 so as to lie on a straight line orthogonal to the straight line LI connecting the center O of the wafer W and the notch N. In other words, the mark M corresponding to the notch N means that the mark M has a clear positional relationship with respect to the notch N.
Further, although the entire character forming step, the step of separating the annular reinforcing area, the step of removing the annular reinforcing area, and the step of detecting the positional relationship in the above preferred embodiment may be same
Laser processing device 1 are executed, these steps are also performed by separate devices.
As described above, the invention has an effect such that the wafer can even be properly aligned after the annular reinforcing area has been removed from the wafer. In particular, the invention is useful as a wafer processing method in the case of removing the annular reinforcing region from a wafer having a reflective foil of metal on the back surface of the device region.
The invention is not limited to the details of the preferred embodiment described above. The scope of the invention is defined by the appended claims, and all changes and modifications which fall within the equivalence of the scope of the claims are therefore included in the invention.

权利要求:
Claims (2)
[1]
Claims:
A method of processing a wafer having a front side, a back side, and an outer periphery, the front side having a component portion where a plurality of components are formed, and a peripheral edge portion surrounding the component portion, the outer periphery a notch to indicate a crystal orientation, and the back has a circular recess corresponding to the device portion, and an annular reinforcing portion corresponding to the peripheral edge portion, characterized by a wafer supporting step, attaching the front side of the wafer to an adhesive tape; is supported in its peripheral region on an annular frame having an inner side opening in the state in which the wafer is placed in the inner side opening of the annular frame, whereby the wafer is supported by the adhesive tape on the annular frame, a step of Separating the annular reinforcing area with d holding the wafer on a holding table in the state where the adhesive tape is in contact with the holding table after the wafer supporting step has been performed, and then applying a laser beam having an absorption wavelength to the wafer, thereby forming a boundary between the annular reinforcing area and cutting the component area together with the adhesive tape to separate the annular reinforcing area from the component area, a step of forming a mark corresponding to the notch at a position radially inward of the boundary area, before or after performing the separation of the annular reinforcing area, and a step of removing the annular reinforcing region by moving the annular reinforcing region supported by the adhesive tape on the annular frame away from the holding table after performing the step of separating the annular reinforcing region and the Sch rode the tag formation, thereby removing the annular reinforcing area from the wafer.
[2]
The method according to claim 1, further characterized by a step of detecting a positional relationship between the notch and the mark formed on the wafer by using detecting means after the step of marking formation has been performed and before the step of separating the reinforcing area is performed becomes.

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DE102014209555A1|2014-11-27|LASER PROCESSING DEVICE

同族专利:

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公开号 | 公开日

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TW201738950A|2017-11-01|

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KR20170119297A|2017-10-26|

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US20170301571A1|2017-10-19|

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MY179206A|2020-11-01|

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KR102327962B1|2021-11-17|

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AT518580A3|2019-04-15|

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JP2017195219A|2017-10-26|

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TWI706455B|2020-10-01|

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JP6672053B2|2020-03-25|

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DE102017206400A1|2017-10-19|

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US10211076B2|2019-02-19|

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CN107305863B|2021-04-23|

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DE102017206400B4|2022-03-03|

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CN107305863A|2017-10-31|

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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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JP2016082781A|JP6672053B2|2016-04-18|2016-04-18|Wafer processing method|

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