• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    A bondhead (1) for mounting components comprises a shaft (2) and a housing part (3) in which the shaft (2) is mounted. The bearing of the shaft (2) allows both a rotation of the shaft (2) about an axis (6), and a displacement of the shaft (2) in the longitudinal direction of the axis (6) by a predetermined stroke H. Der Bondkopf (1 ) further comprises an electric motor comprising a stator and a rotor, the stator being fixed to the housing part (3) and the rotor being fixed to the shaft (2), an encoder for measuring the rotational position of the shaft (2) and a force transmitter to apply a force to the shaft (2). The stator comprises coils (7) which can be acted upon by currents, the rotor comprises a multiplicity of permanent magnets (8). A length of the permanent magnets (8) measured in the longitudinal direction of the axis (6) is shorter or longer by at least the stroke H than an effective length of the coils (7) measured in the longitudinal direction of the axis (6).
    公开号:CH714384A2
    申请号:CH00957/18
    申请日:2018-08-06
    公开日:2019-05-31
    发明作者:Kröhnert Rene
    申请人:Besi Switzerland Ag；
    IPC主号:
    专利说明:

    description
    TECHNICAL FIELD The invention relates to a bonding head for the assembly of components, typically electronic or optical components, in particular semiconductor chips and flip chips, on a substrate. In the professional world, assembly is also known as the bonding process or assembly process. The invention further relates to a semiconductor assembly device, known in the art as die bonders, with such a bonding head.
    Background of the invention Automatic assembly machines with bonding heads of this type are used in particular in the semiconductor industry. An example of such assembly machines are the bonders or pick & place machines with which components in the form of semiconductor chips, micromechanical and micro-optical components and the like are deposited and bonded to substrates such as leadframes, printed circuit boards, ceramics, etc. The components are picked up by a bonding head at a recording location, in particular sucked in, moved to a substrate location and placed on the substrate at a precisely defined position. The bondhead is part of a pick and place system that enables movements of the bondhead in at least three spatial directions.
    The bonding head includes a shaft that is rotatable about an axis and movable in the longitudinal direction of the axis, a drive for rotating the shaft, an encoder to measure the rotational position of the shaft, and a force transducer to support the shaft in the longitudinal direction of the axis to apply a force. The shaft directly receives a component or is designed to be a chip gripper, e.g. a “die collet” for a component.
    A bondhead used by the applicant contains a drive which comprises an electric motor and a gear train formed from two gears, of which one gear is attached to the shaft of the electric motor and the other gear to the shaft of the bondhead.
    BRIEF DESCRIPTION OF THE INVENTION The object of the invention is to develop a bonding head in which the rotational position of the shaft can be positioned with a higher angular accuracy and in which the shaft can be moved in the longitudinal direction of the axis with as little force as possible.
    The stated object is achieved according to the invention by the features of claim 1. Advantageous refinements result from the dependent claims.
    The invention is explained below with reference to exemplary embodiments and with reference to the drawing. The figures are not drawn to scale.
    Description of the Figures
    1 shows schematically and in cross section a first embodiment of a bondhead,
    2 shows the magnet arrangement of the rotor of an electric motor used in the bonding head,
    3 and 4 illustrate length relationships,
    5 shows schematically and in cross section a bonding head with a pneumatic force transmitter,
    6 shows schematically and in cross section a bonding head with a pneumatic force transmitter and an air bearing,
    7 shows schematically and in cross section a bonding head with an integrated temperature control device, and
    8 schematically shows a drive for the bonding head.
    DETAILED DESCRIPTION OF THE INVENTION FIG. 1 schematically shows the cross section of a bonding head 1. The bonding head 1 comprises a shaft 2 and a housing part 3 in which the shaft 2 is mounted. The shaft 2 contains a bore 4 which leads to the tip 5 of the shaft 2 and can be subjected to a vacuum. The tip 5 of the shaft 2 is designed to receive a component or a chip gripper for a component. The mounting of the shaft 2 enables both a rotation of the shaft 2 about an axis 6 and a displacement of the shaft 2 in the longitudinal direction of the axis 6 by a predetermined stroke H (FIG. 3). The diameter of the shaft 2 can have various gradations over its length, as is shown in FIGS. 1, 5 and 6. The bondhead 1 further comprises a drive that is configured to move the shaft 2 around the
    CH 714 384 A2
    To rotate axis 6, an encoder to measure the rotational position of the shaft 2 and a force transducer to apply a force to the shaft 2 in the longitudinal direction of the axis 6. The force is, for example, a predetermined picking force when picking up a component or a predetermined bonding force when mounting the component on a substrate.
    The drive is an electric motor, which comprises a stator and a rotor, wherein the stator is attached to the housing part 3 and the rotor to the shaft 2. The stator comprises coils 7 to which currents can be applied, and the rotor comprises a plurality of permanent magnets 8.
    The electric motor is in principle a commercially available electric motor that has been modified for the purposes of the invention in such a way that the length of the permanent magnets 8 has been shortened by at least the stroke H. This modification brings about a reduction in the torque, but is technically simple and offers the advantage that the mass of the rotor becomes smaller at the same time or can even be minimized at the expense of the torque. The alternative that the length of the coils 7 is extended by at least the stroke H is also possible, but not preferred. The permanent magnets 8 are - as shown in FIG. 2 - flat, cuboid magnets, their two opposite largest surfaces being magnetized as the north pole N and as the south pole S. The permanent magnets 8 are arranged on a circle, their largest surface facing the center of the circle alternately being a north pole N and a south pole S. Their largest surface facing away from the center of the circle is then alternately a south pole S and a north pole N.
    The electric motor serves to rotate the shaft 2 about the axis 6. Because the shaft 2 must be displaceable by the stroke H in the longitudinal direction of the axis 6, the length L-ι (FIG. 3) of the permanent magnets 8 is either shorter by at least the stroke H or longer than the effective length L 2 of the coils 7, so that the forces exerted by the coils 7 on the permanent magnets 8 are independent of the position which the shaft 2 assumes along the longitudinal direction of the axis 6. The coils 7 have a predetermined mechanical length L 3 in the longitudinal direction of the axis 6. The effective length L 2 denotes the length within which the magnetic field which is generated by the currents flowing through the entirety of the coils 7 and which causes the rotation of the permanent magnets 8 about the axis 6, the main proportion of the forces acting on the permanent magnets 8 supplies. The effective length L 2 is therefore shorter than the mechanical length L 3 . FIG. 3 illustrates the case in which the length L-ι of the permanent magnets 8 is shorter by the stroke H than the effective length L 2 of the coils 7, and FIG. 4 illustrates the opposite case in that the length L-ι the Permanent magnets 8 by the stroke H is longer than the effective length L 2 of the coils 7. It is therefore
    L-ι <L 2 - H or L-ι> L 2 + H [0013] In the first case, the permanent magnets 8 (and thus the rotor) remain in the magnetic field of the coils 7 even during the axial displacement along the axis 6, in the second case the permanent magnets 8 protrude from the coils 7 during the entire axial displacement. In both cases, during the axial displacement of the shaft 2, at most a very small force or change in force acting along the axis 6 occurs.
    [0014] The encoder is designed to measure the rotational position of the shaft 2. The encoder is preferably formed by a circular disk 9, which is attached to the shaft 2 and on the edge of which an encoder scale is attached, and an encoder reading head 10, which is attached to the bonding head 1, advantageously to the housing part 3 of the bonding head 1. The encoder scale has 6 lines running in the longitudinal direction of the axis. The length of the lines measured in the longitudinal direction of the axis 6 and the measuring range of the encoder reading head 10 extending in the longitudinal direction of the axis 6 are matched to one another such that the lines lie in the measuring range of the encoder reading head 10 over the entire stroke H of the shaft 2.
    An angle sensor can also be used as an encoder, for example a magnetic angle sensor which determines the rotational position on the basis of the magnetic field generated by the permanent magnets, or an optical angle sensor, or any other angle sensor.
    The force generator serves to generate the picking force as well as the bonding force. For example, a mechanical force transmitter can be used as the force transmitter, in particular a force transmitter in which a spring is used which acts on the shaft 2 in order to generate a force acting in the longitudinal direction of the axis 6. A pneumatic force transmitter can also be used as the force transmitter, as is the case with the bondheads 1, which are shown schematically and in cross section in FIGS. 5 and 6. Here, the housing part 3 and a cover 11 placed on the housing part 3 together with the shaft 2 form a closed cavity 12, the volume of which changes due to the longitudinal movement of the shaft 2. The lid 11 contains a bore 13 through which the cavity 12 can be acted upon by compressed air. The cavity 12 thus forms a pressure chamber and the pressure prevailing in the pressure chamber generates a force acting on the shaft 2. The movement of the shaft 2 in the longitudinal direction of the axis 6, i. H. the stroke H is limited, for example, by a stop. The force generated by the force generator on the one hand causes the shaft 2 to be pressed against the stop in the unloaded state. On the other hand, the force acts on the component when pecking a component and when depositing a component as a bonding force because the shaft 2 is pressed away from the stop when pecking and bonding. The movement of the shaft 2 during these process steps is a passive movement which results from the fact that the shaft 2 comes to a standstill when it is placed on the component as well as when the component is placed on the substrate, during that of a drive 17 (FIG. 8 ) driven bond head is further lowered until the attachment is detected and the drive 17 has been stopped.
    The storage of the shaft 2 in the housing part 3 can for example be a slide bearing, a ball bearing, an air bearing or another suitable bearing. In the exemplary embodiment shown in FIG. 5, the shaft is supported in the housing part 3 by means of a plain bearing, in the exemplary embodiment shown in FIG. 6 by means of an air bearing.
    CH 714 384 A2
    In the air bearing, the housing part 3 has air inlets for the supply of compressed air. In a preferred embodiment of the air bearing, the housing part 3 also has air outlets for the removal of air from the air bearing. The air inlets are, for example, first bores 14 and the air outlets are, for example, second bores 15. If air inlets and air outlets are present, the air inlets are each arranged in the longitudinal direction of axis 6 between some of the air outlets. The air outlets can be connected to the environment so that the ambient pressure is applied to them, or a vacuum (vacuum) can be applied to the air outlets in order to extract the air pressed into the air bearing through the air inlets. The direction of flow of the air in the air inlets and the air outlets is illustrated in FIG. 6 by (laterally offset) arrows. With this arrangement, in which the air inlets are surrounded by the air outlets, part of the air which is pressed through the air inlets into the gap between the shaft 2 and the housing part 3 is prevented from entering the cavity 12 and thus onto the cavity Force acting in the longitudinal direction of the axis 6 changes.
    7 shows schematically and in cross section a bonding head with a temperature control device. The temperature control device serves to keep the temperature of certain parts of the bonding head 1 at a predetermined value. The temperature control device comprises, for example, a pipeline 16, which is advantageously integrated into the housing part 3 as shown and which is part of a closed heat circuit through which a fluid flows, the temperature of which in an external heating, or cooling, or heating and cooling device is regulated to the predetermined value. The fluid can be gaseous or liquid. In certain cases, the temperature control device is an electrical heating resistor which is integrated in the housing part 3. The temperature control device can be used with all bond heads 1. In the case of a bonding head 1 with a pneumatic force transmitter, it can be used, for example, to regulate the temperature prevailing in the pressure chamber to a predetermined value, so that the force generated by the force transmitter is independent of fluctuations in the ambient temperature.
    The bonding head according to the invention is typically used in a semiconductor assembly device, known in the art as die bonders. Such a semiconductor mounting device comprises a drive 17 which is configured to move the bonding head 1 in the longitudinal direction of the axis 6. When picking a component and bonding the component, the bond head 1 is lowered by this drive 17, the shaft 2 being carried passively.
    The bond head offers several advantages, namely:
    - The drive according to the invention for rotating the shaft, in which the rotor is fastened directly to the shaft, is a direct drive and thus a backlash-free drive, which enables the rotational position of the shaft to be approached without play and thus with high precision. This is in contrast to known bond heads, in which a gear transmission is interposed between the drive and the shaft.
    - The measurement of the rotational position of the shaft is a direct and also backlash-free measurement, since the encoder scale is attached to the disc attached to the shaft.
    - The direct drive of the shaft without gear transmission and without toothed belt or the like is wear-free and does not produce any abrasion. This is particularly an advantage in clean room environments where abrasion could damage ICs that contain a semiconductor chip contaminated with particles.
    - The axial displacement of the shaft, i.e. H. the displacement of the shaft along its longitudinal axis is almost without force. This means that the displacement of the shaft along the longitudinal axis when the picking force or the bonding force is built up does not generate any additional force which increases or weakens the force generated by the force generator. This is in contrast to known bond heads, in which a gear transmission or toothed belt is interposed between the drive and the shaft.
    - The construction is space-saving, compact and enables the relatively large bonding force required for the assembly of semiconductor components to be generated with a small installation space and low weight.
    - The mass of the shaft including the rotor is very low. The force acting briefly when the shaft strikes the component is proportional to the momentum, i. H. to the product of the mass and speed of the shaft, and must not exceed a predetermined value, since otherwise the component could be damaged. Smaller mass allows higher speed and thus results in a shorter cycle time.
    - The design of the bond head with an air bearing enables an almost frictionless rotation and displacement of the shaft.
    - The execution of the bonding head with a temperature control device makes it possible to minimize or eliminate influences of temperature fluctuations in the environment on the bonding head and thus on the bonding process.
    [0021] While embodiments of this invention have been shown and described, it will be apparent to those skilled in the art that more modifications than those mentioned above are possible without departing from the inventive concept. The invention is therefore limited only by the claims and their equivalents.
    权利要求:
    Claims (6)
    [1]
    claims
    1. Bond head (1) for the assembly of components on a substrate, comprising a shaft (2), a housing part (3), which comprises a bearing for the shaft (2), the rotation of the shaft (2) about an axis (6) and enables movement of the shaft (2) in a longitudinal direction of the axis (6) by a predetermined stroke (II),
    CH 714 384 A2 a drive to rotate the shaft (2) around the axis (6), an encoder to measure the rotational position of the shaft (2), and a force transducer to rotate the shaft (2) in the longitudinal direction of the axis (6) to be subjected to a force, characterized in that the drive is an electric motor which comprises a stator and a rotor, the stator being fastened to the housing part (3) and the rotor to the shaft (2), the stator being fastened with a Comprises current-carrying coils (7), the rotor comprises a plurality of permanent magnets (8), the stator comprises current-carrying coils (7), the magnetic field generated by the currents flowing through the entirety of the coils (7), causes the rotation of the permanent magnets (8) around the axis (6), and a length (Li) of the permanent magnets (8) measured in the longitudinal direction of the axis (6) is shorter or longer by at least the stroke (H) than one in the longitudinal direction of the axis (6) measured effective length (L 2 ) of the coils (7) i st.
    [2]
    2. Bonding head according to claim 1, characterized in that the encoder comprises a circular disc (9) which is fastened to the shaft (2) and on the edge of which an encoder scale is attached, and an encoder reading head (10), the encoder scale in the longitudinal direction has lines running along the axis (6), and a length of the lines measured in the longitudinal direction of the axis (6) and a measuring range of the encoder reading head (10) extending in the longitudinal direction of the axis are matched to one another such that the lines over the entire stroke (H ) of the shaft (2) are in the measuring range of the encoder read head (10).
    [3]
    3. Bonding head according to claim 1 or 2, characterized in that the force transmitter is a pneumatic force transmitter which has a pressure chamber which can be acted upon by compressed air, the pressure prevailing in the pressure chamber acting on one end of the shaft (2).
    [4]
    4. Bond head according to one of claims 1 to 3, characterized in that the bearing is an air bearing, wherein the housing part (3) has air inlets for the supply of compressed air and air outlets for the removal of air from the air bearing, the air inlets in the longitudinal direction the axis (6) are each arranged between some of the air outlets.
    [5]
    5. Bonding head according to one of claims 1 to 4, further comprising a temperature control device, which serves to keep the temperature of certain parts of the bonding head 1 at a predetermined value.
    [6]
    6. The bonder with a bonding head (1) according to one of claims I to 5, with a drive (17) which is configured to move the bonding head (1) in the longitudinal direction of the axis (6).
    CH 714 384 A2
    CH 714 384 A2
    CH 714 384 A2
    CH 714 384 A2
    类似技术:
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    同族专利:
    公开号 | 公开日
    JP2019096867A|2019-06-20|
    CH714351A1|2019-05-31|
    CN110011439A|2019-07-12|
    TW201923940A|2019-06-16|
    KR20190056985A|2019-05-27|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US5952744A|1996-03-28|1999-09-14|Anoiad Corporation|Rotary-linear actuator|
    CH707378A1|2012-12-21|2014-06-30|Besi Switzerland Ag|Thermocompression method and apparatus for mounting semiconductor chips on a substrate.|
    CH707480B1|2013-01-21|2016-08-31|Besi Switzerland Ag|Bonding head with a heating and cooling suction device.|
    CH707934B1|2013-04-19|2017-04-28|Besi Switzerland Ag|Method for mounting electronic or optical components on a substrate.|JPWO2020235598A1|2019-05-23|2020-11-26|
    法律状态:
    2021-06-15| AZW| Rejection (application)|
    优先权:
    申请号 | 申请日 | 专利标题
    CH01396/17A|CH714351A1|2017-11-17|2017-11-17|Bonding head for the assembly of components.|JP2018195498A| JP2019096867A|2017-11-17|2018-10-17|Bonding head for loading component and die bonder including bonding head|
    FR1860164A| FR3073763B1|2017-11-17|2018-11-05|WELDING HEAD FOR MOUNTING COMPONENTS AND MICROWELDING CHIP WITH SUCH WELDING HEAD|
    US16/180,243| US20190157122A1|2017-11-17|2018-11-05|Bonding head for mounting components and die bonder with such a bonding head|
    TW107139446A| TW201923940A|2017-11-17|2018-11-07|Bonding head for mounting components and die bonder with such a bonding head|
    CN201811346241.6A| CN110011439A|2017-11-17|2018-11-13|For the joint head of mounting assembly and the chip mounter with this joint head|
    DE102018128615.5A| DE102018128615A1|2017-11-17|2018-11-14|Bonding head for the assembly of components and die bonders with such a bonding head|
    KR1020180139732A| KR20190056985A|2017-11-17|2018-11-14|Bonding head for mounting components and die bonder with such a bonding head|
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