Chip bonding head equipment with chip holder motion stage

Abstract

The present invention provides a chip bonding head device, which has a chip bonding head body connected to a chip bonding head moving stage, a chip holder moving stage mounted on the chip bonding head body, and a chip holder operable to fix a semiconductor chip to a substrate when in use. The chip holder can be positioned by the chip holder moving stage independent of the chip bonding head moving stage.

Description

Technical Field

[0001] The present invention relates to a chip bonding head device and method for bonding a semiconductor chip to a surface with high precision. Background Art

[0002] In high-precision semiconductor packaging equipment, vision systems are often used to determine critical positions, such as the position of the chip relative to the substrate during bonding. The offset between the chip position and the substrate is compensated by moving the bond head supporting the chip holding tool to ensure the placement accuracy of the chip on the substrate.

[0003] However, in existing equipment, the placement accuracy of the chip on the substrate and its placement speed are limited. This is because the compensation of the chip position is usually performed by controlling the motion stage of the chip holding bond head. Generally, the tip of the chip holding tool of the bond head is not positioned at the control point of the chip bond head motion stage. Therefore, even after compensation, the chip position identified by the vision system may not achieve sub-micron accuracy.

[0004] It would be beneficial to provide more accurate and faster chip placement compared to existing technologies. Summary of the invention

[0005] It is therefore an object of the present invention to seek to provide an apparatus which overcomes at least some of the above-mentioned problems of the prior art.

[0006] According to a first aspect of the present invention, a chip bonding head device is provided, comprising: a chip bonding head body, which is connected to a chip bonding head moving stage; a chip holder moving stage mounted on the chip bonding head body; a chip holder that can be operated to fix a semiconductor chip to a substrate when in use, and the chip holder can be positioned by the chip holder moving stage independent of the chip bonding head moving stage. It is recognized from the first aspect that the problem of the existing chip bonding head device is that it is difficult to achieve high-precision placement of the chip on the substrate. This may be due to the fact that the distance between the chip holder carried by the chip bonding head body and the moving stage driving the chip bonding head body may be relatively large, which means that the movement of the moving stage may lead to undesired positioning of the chip holder. In particular, under the drive of the moving stage, the sub-micron positioning accuracy of the chip holder may not be achieved. Similarly, the control system driving the moving stage may cause unstable operation, in which case the positioning of the chip holder is different from the expected position.

[0007] Therefore, a device is provided. The device may be a chip bonding head device, which may include a chip bonding head body. The chip bonding head body may be connected to, mounted on or carried on a chip bonding head moving stage. The device may include a chip holder moving stage. The chip holder moving stage may be connected to, mounted on or carried on the chip bonding head body. The device may include a chip holder. The chip holder may be connected to, mounted on or carried on the chip holder moving stage. And, the chip holder can be used to fix, place or position a semiconductor chip on a substrate. The chip holder can be positioned by the chip holder moving stage. In this way, a dual moving stage setting is provided, in which one moving stage moves the chip bonding head body (including the chip holder) and another second moving stage moves the chip holder. This allows the chip bonding head body to be positioned near the chip placement position on the substrate, and the chip holder moving stage can accurately position the chip holder at the placement position. In this way, the distance between the chip holder itself and the chip holder moving stage is reduced, which means that the movement of the chip holder moving stage can make the positioning of the chip holder more accurate. In particular, under the drive of the chip holder moving stage, the chip holder can achieve sub-micron positioning accuracy. Similarly, the control system that drives the chip holder moving stage can position the chip holder at the desired position more quickly and accurately.

[0008] In one embodiment, the die bond head moving stage is coupled to a first end of the die bond head body, and the die holder moving stage is mounted at a second end of the die bond head body away from the first end. Thus, the die bond head moving stage can be positioned toward one end of the die bond head body, while the die holder moving stage can be positioned toward the other end of the die bond head body. This means that an inaccurate positioning of the die bond head caused by the die bond head moving stage can be corrected by moving the die holder moving stage closer to the die holder.

[0009] In one embodiment, the chip holder moving stage is operable to displace the chip holder relative to at least one of the chip bond head body and the chip bond head moving stage when in use. Thus, the chip holder moving stage can change the position of the chip holder relative to the chip bond head body and / or the chip bond head moving stage.

[0010] In one embodiment, the chip holder motion stage is operable, when in use, to displace the chip holder along more than one axis on a plane. Thus, the chip holder motion stage may displace or move the chip holder along one or two axes of the plane.

[0011] In one embodiment, the chip holder motion stage is operable, when in use, to displace the chip holder along at least one axis common to the chip bond head motion stage. The chip bond head motion stage may displace the chip bond head body along more than one axis in a plane and an axis transverse to the plane. The chip holder motion stage may displace the chip holder along the same one or more axes as the chip bond head motion stage.

[0012] In one embodiment, the die holder moving stage is operable to more precisely displace the die holder when in use than the die bond head moving stage is operable to displace the die bond head body when in use. Thus, the die holder moving stage can more precisely position the die holder than the die bond head moving stage positions the die bond head body.

[0013] In one embodiment, the displacement range of the chip holder motion stage is smaller than the displacement range of the chip bond head motion stage. Therefore, compared with the chip bond head motion stage, the chip holder motion stage may have a smaller moving position range.

[0014] In one embodiment, the die holder moving stage has a stage support structure held by the die bond head body and a movable structure capable of shifting relative to the stage support structure. Thus, the die bond head moving stage may have a stage support or fixed structure attached to the die bond head body and a movable or shiftable structure movable relative to the stage support structure.

[0015] In one embodiment, the chip holder motion stage comprises at least one actuator operable, when in use, to displace the movable structure relative to the stage support structure. Thus, one or more actuators may be provided which, when in operation, move or reposition the movable structure relative to the stage support structure.

[0016] In one embodiment, the at least one actuator is operable, in use, to displace the moveable structure along more than one axis.Thus, the actuator may be used to move the moveable structure along one or more axes on the plane.

[0017] In one embodiment, the at least one actuator is operable, in use, to rotate the moveable structure about at least one axis.Thus, the actuator may be used to rotate or pivot the moveable structure about an axis extending transversely to the plane.

[0018] In one embodiment, the chip holder motion stage comprises: at least one of a bearing and a flexure, which couples the movable structure to the stage support structure and is operable to facilitate movement of the movable structure relative to the stage support structure when in use. Thus, bearings and / or flexures may be provided to assist or enable movement of the movable structure relative to the stage support structure.

[0019] In one embodiment, the chip holder motion stage comprises a position marker operable to indicate the position of the movable structure.Thus, a marker may be provided which may provide information to help identify the position or location of the movable structure.

[0020] In one embodiment, the chip holder is carried by the movable structure. Thus, the chip holder may be mounted on or carried by the movable structure.

[0021] In one embodiment, the chip holder is located on the movable structure and faces the substrate. Thus, the chip holder can be positioned so that once it is moved towards the substrate, the chip held by the chip holder is pressed against the substrate.

[0022] In one embodiment, the position marker comprises a linear encoder having respective components mounted on the movable structure and the stage support structure, respectively. Thus, one or more linear encoders may be provided to provide position information of the movable structure relative to the stage support structure.

[0023] In one embodiment, the movable structure comprises at least one inspection light path passing through the movable structure, the inspection light path being positioned to image at least a portion of the semiconductor chip held by the chip holder. Thus, the position of the semiconductor chip can be determined by imaging the inspection light path in the movable structure.

[0024] In one embodiment, the inspection optical path comprises a gap in the movable structure.

[0025] In one embodiment, the apparatus comprises at least one imaging device operable, when in use, to image at least a portion of the semiconductor chip held by the chip holder, thereby providing at least one of position and orientation information of the semiconductor chip. Thus, the imaging device may image the semiconductor chip to provide position and / or orientation information about the semiconductor chip.

[0026] In one embodiment, the apparatus includes a controller operable, when in use, to position the chip holder near a bonding position by manipulating the position of the bond head body using the chip bond head moving stage, and to correct at least one of the position and orientation of the semiconductor chip held by the chip holder in response to at least one of the position and orientation information by manipulating the position of the chip holder using the chip holder moving stage. Thus, the chip bond head moving stage can be operated to position the bond head body near a bonding position, and the chip holder moving stage can position the chip holder more accurately at the bonding position.

[0027] According to a second aspect of the present invention, a method is provided, comprising: positioning a chip holder of the chip bonding head device described in the first aspect near a bonding position by manipulating the position of a bonding head body using a chip bonding head moving stage; correcting at least one of the position and orientation of a semiconductor chip held by the chip holder by manipulating the position of the chip head using the chip holder moving stage; and bonding the semiconductor chip at the bonding position.

[0028] These and other features, aspects and advantages will become better understood with reference to the specification portion, appended claims and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings.

[0030] Figure 1 A chip bonding head device according to a first embodiment of the present invention is schematically shown.

[0031] Figure 2 is a side view of the die bonding head apparatus according to the first embodiment.

[0032] Figure 3 is a side view of a die bonding head apparatus according to a second embodiment of the present invention.

[0033] Figure 4 It is a plan view of a movable platform and a machine support structure according to the second embodiment.

[0034] Figure 5 1 is a top view of the movable platform and the machine table support structure according to the first embodiment.

[0035] In the drawings, the same components are denoted by the same reference numerals. DETAILED DESCRIPTION

[0036] Before discussing the embodiments in more detail, an overview is first given. An embodiment of the present invention provides a device having a main body mounted on a moving stage, and another moving stage mounted on the main body carrying a holder. The two moving stages can be operated independently of each other to position the holder at a desired position. Generally, the position control of the moving stage carrying the holder is more precise than the position control of the moving stage carrying the main body. Compared with using a single moving stage, the method of two moving stages helps to position the holder more accurately and quickly. For example, one embodiment includes at least one moving stage system. The moving stage system includes: a micro-moving stage capable of moving in the X-axis and Y-axis directions and in a rotational direction (usually around the Z-axis); an encoder scale for the micro-moving stage in the XY direction and an encoder reading head for the micro-moving stage. The micro-moving stage is mounted on a bonding head module and includes an XY actuator, such as a voice coil motor, an air bearing, and an XY scale. The reading head is mounted on other modules, such as an optical system. Since the position of the micro-moving stage is controlled by a reference reading head on the optical system, the position of the micro-moving stage relative to the optical system is controlled. Therefore, even if the micro-motion stage and the vision system are subjected to different lateral vibrations, the position of the micro-motion stage observed and determined by the optical system via the optical path can be maintained in real time. Therefore, the position of the micro-motion stage is always located at the position viewed by the vision system. This method can improve the position and orientation accuracy of the chip in the process of correcting the relative offset between the chip and the bonding position before placing the chip on the bonding position.

[0037] Chip bonding head equipment

[0038] Figure 1 A chip bonding head device according to a first embodiment of the present invention is schematically shown. It is provided with a chip bonding head moving table 2, to which one end of a chip bonding head body 1 is attached. The chip bonding head moving table 2 is generally configured to displace the chip bonding head body 1 along the X, Y and Z axes. It is also provided with a chip holder moving table 3, which is attached to the other end of the chip bonding head body 1. The chip holder moving table 3 can move along the X-axis and the Y-axis and rotate around the Z-axis. The chip holder moving table 3 carries a chip holder 4 and a position encoder scale 5. The chip holder moving table 3 is effectively mounted on the chip bonding head moving table 2 through the chip bonding head body 1. The moving table carries an optical system 7. The optical system 7 carries an encoder reading head 6 for reading the encoder scale 5.

[0039] In operation, the optical system 7 is usually positioned at the placement position using the optical system moving stage, where the chip (not shown) is placed on the substrate (not shown). The optical system 7 images the placement position on the substrate. The chip bonding head moving stage 2 moves the chip bonding head body 1 to the pick-up position and picks up the chip using the chip holder 4. After picking up the chip, the chip is held by the chip holder 4, and the chip bonding head moving stage 2 positions the bonding head body 1 (together with the chip holder moving stage 3 and the chip holder 4 holding the chip) near the optical system 7 at the placement position. When the chip holder 4 holding the chip approaches the placement position, the optical system 7, especially the encoder reading head 6, detects the current reading of the encoder scale 5. Then, the chip bonding head moving stage 2 stops moving the chip bonding head body 1, and starts the chip holder moving stage 3 to position the chip holder moving stage 3 and the chip holder 4 holding the chip at the placement position. Control of the chip holder motion stage 3 is achieved through feedback provided by the encoder read head 6 when reading the encoder scale 5. Once in the correct position, the chip holder 4 can then place the chip on the substrate at the correct placement position.

[0040] The chip can be positioned more accurately by means of the chip bond head motion stage 2 (for moving the position of the chip bond head body 1) and a separate, independently controlled chip holder motion stage 3 (for adjusting the position of the chip holder 4). In particular, it has been found that it is difficult to achieve sub-micron placement accuracy of the chip without the chip holder motion stage 3. This is because the optical system 7 detects that when trying to achieve higher positioning accuracy, the movement of the chip bond head motion stage 2 causes the position of the chip bond head body 1 (and the chip holder 4) to be different from the expected position. This may result in the chip bond head motion stage 2 being started again to further move the chip bond head body 1 (and the chip holder 4) to correct the deviation, which may still cause the position of the chip holder 4 to be different from the expected position. The deflection of the chip bond head body 1 or the thermal effect that causes the movement of the chip bond head body 1 may make this problem more complicated. However, by providing a separate motion stage, the positioning of the chip holder 4 at the placement position can be achieved more accurately and more quickly. In particular, the size and movement displacement of the chip holder moving stage 3 can be significantly smaller than those of the chip bonding head moving stage 2, which means that the position of the chip holder moving stage 3 can be more accurately controlled and is less susceptible to the mechanical and thermal effects on the chip bonding head body 1.

[0041] Chuck reference mark

[0042] Figure 2 FIG. 1 is a side view of a chip bonding head device according to a first embodiment of the present invention. Figure 1The arrangement shown is shown, and the view focuses on the arrangement of the optical system 7A and the chip holder moving stage 3A. It can be seen that the chip holder moving stage 3A is connected to the chip bonding head body 1A. The chip holder moving stage 3A has: a stage support structure 20A fixed on the chip bonding head body 1A; and a movable platform 30A movable relative to the stage support structure 20A. A plurality of air bearings 11A are provided to facilitate the movement of the movable platform 30A relative to the stage support structure 20A. A plurality of micro XY coils 9A are provided on the movable platform 30A, which interact with a corresponding number of micro XY magnets 10A provided on the stage support structure 20A. A plurality of encoder scales 5A are located on the surface facing the field of view of the optical system 7A.

[0043] A chip holder (chuck) 4A is located on the main surface of the movable platform 30A, facing the substrate 17A, on which the chip 16A will be placed. The chip holder 4A is operable to pick up the chip 16A and maintain the position of the chip 16A. The chip holder 4A has a plurality of chuck reference marks 19A visible to the optical system through an aperture 40A in the movable platform 30A. The optical system 7A has a camera 50A that images the chuck reference marks 19A. The reading head 6A is mounted on the optical system 7A.

[0044] In operation, the optical system 7A is positioned by its moving stage to image the substrate reference mark 18A on the substrate 17A at the position where the chip is to be placed. In other words, before the chip bonding head body 1A is moved there for adjustment and placement, the target bonding position of the substrate 17A is determined by the substrate reference mark 18A using the optical system 7A.

[0045] The chip bond head body 1A is positioned to pick up the chip at the pick-up position. Then, the chip bond head motion stage 2 moves the chip bond head body 1A close to the placement position so that the movable platform 30A enters the field of view 12A of the optical system 7A. Once the chip bond head body 1A stops moving under the control of the chip bond head motion stage 2, the optical system 7A determines the position of the chip 16A by imaging the chuck reference mark 19A. Based on the feedback from the encoder read head 6A and the imaging of the chuck reference mark 19A, the micro XY coil 9A is appropriately energized to move the movable platform 30A to the correct position. Once the chip 16A is correctly positioned and / or oriented at the placement position, the chip 16A is placed on the substrate 17A by moving the chip bond head body 1A toward the substrate 17A in the Z direction.

[0046] In other words, the chip holder motion stage 3A is controlled based on the information provided by the read head 6A. Thus, the position of the chip 16A and the chip holder 4A on the chip holder motion stage 3A relative to the optical system 7A is controlled. The position of the chip 16A is identified by the optical system 7A via the optical path 12A and the motion stage through a hollow feature formed in the form of an aperture 40A to image the chuck reference mark 19A. Even if the relative position of the bond head motion stage 2 and the frame optical system 7A changes independently in lateral direction, the position can be maintained at sub-micron accuracy in real time. In the worst case, the frame optical system 7A can be located on a second motion stage so that the position of the chip holder motion stage 3A is controlled by a different reference frame. Thus, the chip bond head motion stage 2 and the optical system can be positioned in two different reference frames without the need for a known positional relationship. To eliminate this uncertainty, if the optical system motion stage can be moved, the position of the chip bond head motion stage 2 can be further controlled with reference to the read head 6A or the optical system motion stage mounted on the frame optical system 7A. After the chip holder moving stage 3A moves in the XY direction to compensate for the error recognized by the vision system, the position of the chip 16A moves within the target area recognized again by the frame optical system 7A. Then, the chip holder moving stage 3A drives the chip 16A downward, and sub-micron bonding accuracy can be achieved.

[0047] Chip fiducial marks

[0048] Figure 3 4B is smaller than the chip holder 4A described above so that the chip fiducial mark 15B can be imaged directly by the optical system 7B. Figure 2 The embodiment shown is the same. Thus, the chip 16B is aligned with the substrate 17B by energizing the micro XY coils 9B to rotate the movable platform 30B about the Z axis to accommodate any rotational offset of the chip 16B about the Z axis.

[0049] Figure 4 A plan view of the movable platform 30B as viewed by an optical system 7B configured to image a chip fiducial mark 15B of a chip 16B through a hollow feature formed in the form of an aperture 14B in the motion stage is shown. It can be seen that a micro XY magnet 10B and micro XY coil 9B are located on each side of the movable platform 30B to allow movement along the X and Y axes (assisted by air bearings 11B) and to enable rotation of the movable platform 30B about the Z axis. Feedback of the current position of the movable platform 30B is provided by an encoder scale 5B.

[0050] Figure 5An alternative arrangement of a movable platform and a stage support structure is shown. In this arrangement, instead of air bearings, one or more flexures 11C are provided which support the movable platform 30C within the stage support structure 20C while enabling the movable platform 30C to move relative to the stage support structure 20C.

[0051] Although the invention has been described in considerable detail with reference to certain embodiments, other embodiments are possible. In particular, the movable platform may be actuated by a voice coil motor or a piezoelectric actuator.

[0052] Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein.

Claims

1. A chip bonding head device, comprising: a die bond head body coupled to the die bond head motion stage to move the die bond head body along at least one axis; a chip holder moving stage mounted on the chip bonding head body; a chip holder operable, in use, to secure a semiconductor chip to a substrate, the chip holder being positionable by the chip holder motion stage to move the chip holder along the at least one axis independently of the chip bond head motion stage; as well as an imaging device, which is located on the substrate and is operable to image a placement position on the substrate when in use, the imaging device being configured so that the chip holder moving stage can be moved to a position between the imaging device and the substrate so that the chip holder moving stage is positioned between the imaging device and the chip holder, wherein the imaging device is further operable to image at least a portion of the chip holder and / or the semiconductor chip held by the chip holder to determine at least one of position and orientation information of the chip holder and / or the semiconductor chip after the chip bond head body is positioned near the placement position along the at least one axis by the chip bond head moving stage, wherein the chip holder moving stage is further operable to adjust the position and orientation of the chip holder and / or the semiconductor chip relative to the placement position, The chip holder moving stage comprises at least one aperture through which at least one inspection light path passes through the chip holder moving stage to allow an imaging device to image at least a portion of the chip holder and / or the semiconductor chip held by the chip holder.

2. The device according to claim 1, wherein: The die bond head moving stage is coupled to a first end of the die bond head body, and the die holder moving stage is installed at a second end of the die bond head body away from the first end.

3. The device according to claim 1, wherein: The die holder moving stage is operable, in use, to displace the die holder relative to at least one of the die bond head body and the die bond head moving stage.

4. The device according to claim 1, wherein: The chip holder motion stage is operable, in use, to displace the chip holder along more than one axis on a plane.

5. The device according to claim 1, wherein: The chip holder moving stage is operable to more precisely displace the chip holder when in use, compared to the chip bond head moving stage which is operable to displace the chip bond head body when in use.

6. The device according to claim 1, wherein: The displacement range of the chip holder moving stage is smaller than the displacement range of the chip bonding head moving stage.

7. The device according to claim 1, wherein: The chip holder moving stage has a stage supporting structure held by the die bonding head main body and a movable structure capable of being displaced relative to the stage supporting structure.

8. The device according to claim 7, wherein: The chip holder motion stage comprises at least one actuator operable, in use, to displace the movable structure relative to the stage support structure.

9. The device according to claim 8, wherein: The at least one actuator is operable, in use, to displace the moveable structure along more than one axis.

10. The device according to claim 7, wherein: The chip holder motion stage comprises at least one of a bearing and a flexure coupling the movable structure with the stage support structure and being operable, in use, to facilitate movement of the movable structure relative to the stage support structure.

11. The device according to claim 7, wherein: The chip holder motion stage includes a position marker operable to indicate a position of the movable structure.

12. The device according to claim 11, wherein The position marker includes a linear encoder having corresponding components mounted on the movable structure and the stage support structure, respectively.

13. The apparatus according to claim 7, wherein: The movable structure comprises the at least one aperture through which the at least one inspection light path passes through the movable structure, the inspection light path being positioned to image the chip holder and / or at least a portion of the semiconductor chip held by the chip holder.

14. The apparatus according to claim 1 comprises a controller which, when in use, is operable to position the chip holder near a bonding position by manipulating the position of the chip bond head body using the chip bond head motion stage, and to correct at least one of a position and an orientation of the semiconductor chip held by the chip holder in response to at least one of position information and orientation information by manipulating the position of the chip holder using the chip holder motion stage.

15. A chip bonding method, comprising: imaging the placement position on the substrate using the imaging device of the chip bonding head equipment according to claim 1, positioning a chip holder of a chip bond head apparatus near a placement position by manipulating the position of a chip bond head body using a chip bond head motion stage so that the chip holder motion stage moves to a position between the imaging device and the substrate; imaging the chip holder and / or at least a portion of the semiconductor chip held by the chip holder through the chip holder motion stage using an imaging device to determine at least one of position and orientation information of the chip holder and / or the semiconductor chip, wherein the chip holder motion stage comprises at least one aperture through which at least one inspection light path passes through the chip holder motion stage to allow the imaging device to image the chip holder and / or at least a portion of the semiconductor chip held by the chip holder; adjusting at least one of a position and an orientation of a semiconductor chip held by the chip holder relative to the placement location using the chip holder motion stage; as well as The semiconductor chip is bonded at the placement location.

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