Joined body manufacturing device and joined body manufacturing method

Abstract

The invention provides a bonded body manufacturing device and a bonded body manufacturing method which can better transfer a bonding material to a chip. A bonded body manufacturing device (10) is provided with: a stage (12) on which a transfer sheet (110) in which a release sheet (112) and a bonding material (114) are laminated is placed, and which sucks and holds the transfer sheet (110); a tool head (14) having a suction tool (30) for holding the chip (102); and a controller (16) configured so that the bonding material (114) and the chip (102) are bonded by moving the suction tool (30) in a state in which the chip (102) is held, and pressing the chip (102) against the bonding material (114), and so that the suction and release of the suction of the transfer sheet (110) by the stage (12) are switched in conjunction with the movement of the suction tool (30).

Description

Technical Field

[0001] This specification discloses a bonded body manufacturing apparatus and a bonded body manufacturing method for manufacturing a bonded body in which a bonding material is transferred to a chip. Background Art

[0002] In recent years, sintering bonding using nanoparticles or microparticles of metals such as silver (Ag) has been proposed to bond a chip to a circuit board. To enable the sintering bonding, it has been proposed to transfer a bonding material including a sintering material in advance to the lower surface of the chip.

[0003] For example, a technique for transferring a bonding material (referred to as a "sintered film" in Patent Document 1) to a chip is disclosed in Patent Document 1. In Patent Document 1, the bonding material is transferred to the chip by pressurizing and heating the chip while the chip and the bonding material are in contact with each other.

[0004] [Prior art literature]

[0005] [Patent Document]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2020-056110 Summary of the invention

[0007] [Problems to be solved by the invention]

[0008] However, if the bonding between the chip and the bonding material is weak, when the chip is lifted after the bonding process, part of the bonding material may be peeled off from the chip. In other words, part of the bonding material transferred to the chip may be lost.

[0009] Therefore, this specification discloses a bonded body manufacturing apparatus and a bonded body manufacturing method that can transfer a bonding material to a chip more satisfactorily.

[0010] [Technical means to solve the problem]

[0011] The bonding body manufacturing device disclosed in the present specification includes: a carrier, on which a transfer sheet formed by stacking a release sheet and a bonding material is placed, and the transfer sheet is sucked and held; a tool head, which has a tool for holding a chip; and a controller, wherein the controller is configured to move the tool relative to the transfer sheet and bring the held chip into contact with the bonding material for bonding, and then separate the tool from the release sheet, and adjust the suction force of the transfer sheet based on the carrier or the tension of the transfer sheet in conjunction with the separation of the tool.

[0012] In the case, the controller may be configured to raise the tool together with the chip after the tool contacts the bonding material, while the suction of the transfer sheet by the stage is released, and then restart the suction of the transfer sheet.

[0013] Furthermore, the controller may restart the suction by the stage when the chip reaches a predetermined restart height.

[0014] In the above case, the restart height may be a variable value that changes according to at least one of the type of the chip and the position of the transfer region transferred to the chip in the transfer sheet.

[0015] Furthermore, the stage may be capable of partially switching the suction state of the transfer sheet, and the controller may be configured to release the suction of the transfer sheet only within a certain range from a transfer area to the chip after the bonding of the bonding material.

[0016] Furthermore, the tool head may include a vibration source for applying ultrasonic vibration to the chip, and the controller may be further configured to apply ultrasonic vibration to the chip when the chip is pushed against the bonding material.

[0017] The manufacturing method of the bonding body disclosed in this specification utilizes a carrier to suck and hold a transfer sheet formed by stacking a release sheet and a bonding material, moves a tool holding a chip to push the chip against the bonding material, thereby bonding the bonding material to the chip, and switches the suction and release of the transfer sheet based on the carrier in conjunction with the movement of the tool.

[0018] [Effects of the Invention]

[0019] According to the technology disclosed in this specification, the suction and suction release of the transfer sheet are switched in conjunction with the movement of the tool and the chip, thereby preventing excessive force from being applied to the bonding material bonded to the chip. As a result, the bonding material can be effectively prevented from being chipped and the bonding material can be transferred to the chip more effectively. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram showing the structure of a joint body production apparatus.

[0021] Figure 2 It is a schematic diagram showing the manufacturing process of the joint body.

[0022] Figure 3 This is a flow chart showing the manufacturing process of the joint body.

[0023] Figure 4 This is a diagram showing an example of another tool head.

[0024] Figure 5 This is a diagram showing an example of another stage.

[0025] Figure 6 This is a diagram showing an example of an existing transfer process.

[0026] Figure 7 This is a diagram showing an example of a notch in the bonding material.

[0027] [Description of symbols]

[0028] 10: Bonding body manufacturing apparatus

[0029] 12: Stage

[0030] 14: Tool head

[0031] 16: Controller

[0032] 22: Support layer

[0033] 24: Fixture

[0034] 26: Chip suction source / Suction source

[0035] 30: Suction tool

[0036] 32: Vibration source

[0037] 34: Chip suction source / Suction source

[0038] 36: Height sensor

[0039] 40: Processor

[0040] 42: Memory

[0041] 46: Swing axis

[0042] 48: Swing mechanism

[0043] 50a, 50b, 50c, 50d, 50e, 50f: Suction path

[0044] 52a, 52b, 52c, 52d, 52e, 52f: Valve

[0045] 100: Bonding body

[0046] 102: Chip

[0047] 110: Transfer sheet

[0048] 112: Release sheet

[0049] 114: Bonding material

[0050] 115: Notch

[0051] Aa, Ab, Ac, Ad, Ae, Af: Areas

[0052] Hd: Restart height

[0053] S10, S12, S14, S16, S18, S20, S22, S24, S26, S28, S30: Steps Detailed implementation manner

[0054] Hereinafter, the structure of the bonding body manufacturing apparatus 10 will be described with reference to the drawings. Figure 1 is a schematic diagram showing the structure of the bonding body manufacturing apparatus 10. In addition, in Figure 1 , in order to ensure visibility, the dimensional ratios of the respective members are changed to be larger than the actual dimensional ratios. In particular, the thickness of the transfer sheet 110 relative to the size of the chip 102 is shown to be much larger than the actual. Actually, for example, when one side of the chip 102 is several millimeters, the thickness of the transfer sheet 110 is about several tens of μm or 100 μm.

[0055] In order to obtain a bonding body 100 (refer to Figure 2 ) in which a bonding material 114 is bonded to a semiconductor chip (hereinafter referred to as "chip 102"), the bonding body manufacturing apparatus 10 transfers the bonding material 114 to the bottom surface of the chip 102. The bonding body manufacturing apparatus 10 includes a stage 12, a tool head 14, and a controller 16.

[0056] The stage 12 mounts the transfer sheet 110 and sucks the transfer sheet 110. The transfer sheet 110 is a sheet in which the bonding material 114 and the release sheet 112 are laminated. The release sheet 112 is a sheet that supports the bonding material 114 and contains, for example, resin. The bonding material 114 contains, for example, metal and is a thin film transferred to the chip 102. The bonding material 114 is, for example, a film-like sintering bonding composition containing at least sinterable particles containing conductive metal and a binder component. The sinterable particles are particles containing a conductive metal element and capable of sintering. The sinterable particles are composed of, for example, gold, silver, copper, palladium, tin, nickel, and an alloy of two or more metals selected from these groups. The cutout 115 corresponding to the shape of the chip 102 described later can be formed in the bonding material 114 in advance. For example, when the chip 102 is a rectangle of a specified size, the cutouts can be formed in a lattice pattern in the bonding material 114 in a rectangular arrangement of the specified size.

[0057] A support layer 22 is provided on the upper surface of the stage 12, and the bonding material 114 is placed above the support layer 22. The support layer 22 includes rigid materials such as metals like stainless steel and aluminum, or ceramics. Additionally, a plurality of suction holes (not shown) are formed on the surface of the stage 12. The suction holes are fluidly connected to the sheet suction source 26. The sheet suction source 26 applies a negative pressure to the transfer sheet 110 via the suction holes and is, for example, a suction pump. By driving the sheet suction source 26, the transfer sheet 110 is suction-held on the upper surface of the stage 12.

[0058] A jig 24 is also provided on the stage 12. The jig 24 fixes the end portion of the transfer sheet 110 to the stage 12 by pressing the end portion of the transfer sheet 110 toward the upper surface of the stage 12. In the illustrated example, the jig 24 presses and fixes the right end and the left end of the transfer sheet 110 to the stage 12.

[0059] The tool head 14 has a suction tool 30 for suction-holding the chip 102 and a moving mechanism (not shown) for moving the suction tool 30. By the moving mechanism, the suction tool 30 can move in the horizontal and vertical directions. A suction hole (not shown) is formed on the end face of the suction tool 30. The suction hole is fluidly connected to the chip suction source 34. The chip suction source 34 applies a negative pressure to the chip 102 via the suction hole and is, for example, a suction pump. By driving the chip suction source 34, the chip 102 is suction-held on the suction tool 30. Then, the chip 102 is transported by moving the suction tool 30 while the chip 102 is suction-held. The height sensor 36 detects the height of the suction tool 30 and thus the chip 102 and sends it to the controller 16.

[0060] The tool head 14 also has a vibration source 32. The vibration source 32 applies ultrasonic vibration to the suction tool 30 and thus to the chip 102 held on the suction tool 30. The vibration source 32, for example, has an ultrasonic vibration element and an AC power supply. The ultrasonic vibration element receives a drive signal as a voltage signal and generates longitudinal vibration. The ultrasonic vibration element is, for example, the following oscillator, that is, a Lead Zirconate Titanate (PZT) (commonly called PZT) that vibrates upon receiving an AC voltage, and a Bolt-clamp Langevin Transducer (BLT) (commonly called BLT or BL oscillator) that sandwiches the PZT with a metal block and applies a fastening pressure with a screw (bolt). After the controller 16 described later brings the chip 102 into contact with the transfer sheet 110, the vibration source 32 is driven to apply ultrasonic vibration to the chip 102. And, through the ultrasonic vibration, the bonding material 114 and the chip 102 are ultrasonically bonded.

[0061] The controller 16 controls the operation of each part of the joint body manufacturing device 10. For example, the controller 16 controls the movement of the suction tool 30, the on / off of the suction source 26 and the suction source 34, the on / off of the vibration source 32, etc. The controller 16 is physically a computer having a processor 40 and a memory 42. Figure 1 In the figure, the controller 16 is shown as a single computer, but the controller 16 may be composed of a plurality of physically separate computers.

[0062] Next, a description will be given of a flow of manufacturing the bonded body 100 using the bonded body manufacturing apparatus 10 . Figure 2 is a schematic diagram showing the manufacturing process of the joint body 100. Figure 3 1 is a flowchart showing the manufacturing process. When the bonding material 114 is transferred to the chip 102 to manufacture the bonded body 100, first, the transfer sheet 110 is set on the stage 12 (S10). Then, the transfer sheet 110 is sucked by the sheet suction source 26 (S12).

[0063] The controller 16 uses the suction tool 30 to suck and hold the chip 102, and moves the suction tool 30 to the top of the transfer area of ​​the transfer sheet 110. Then, the suction tool 30 and the chip 102 are slowly lowered toward the transfer sheet 110 (S14). As a result of the descent, when the chip 102 contacts the transfer sheet 110 (Yes in S16), the controller 16 pressurizes the chip 102 and abuts the chip 102 against the bonding material 114 (S18). In addition, the controller 16 drives the vibration source 32 in the above state to apply ultrasonic vibration to the chip 102 (S18). Figure 2 The upper part of shows the above state. By applying ultrasonic vibration to the chip 102 , the bonding material 114 is ultrasonically bonded and transferred to the chip 102 .

[0064] If the bonding material 114 is bonded to the chip 102, the controller 16 then raises the suction tool 30 to move the chip 102 (S22). At this time, the controller 16 switches the suction and release of the transfer sheet 110 by the sheet suction source 26 in conjunction with the movement of the suction tool 30 (S20 to S26). This is described in comparison with the prior art.

[0065] In the past, the bonding material 114 was mostly bonded (i.e., transferred) using heat and pressure rather than ultrasound. Figure 6 As shown in the upper section of FIG. 1 , the chip 102 is heated and pressurized while the chip 102 is in contact with the bonding material 114. Thus, the bonding material 114 and the chip 102 are thermally eutectic bonded. After bonding, the chip 102 is lifted while the transfer sheet 110 is sucked by the stage 12.

[0066] However, in the case of thermal eutectic bonding, as Figure 6 shown in the lower part of, due to the influence of heat, a rounded shape (rounded corner) in which the corners of the bonding material 114 bonded to the chip 102 are easily rounded and missing is likely to occur. Such a rounded shape becomes a cause of defects in the subsequent processes of semiconductor manufacturing.

[0067] Therefore, it can be considered to perform ultrasonic bonding on the bonding material 114 instead of thermal eutectic bonding. By ultrasonic bonding, the above-mentioned rounded shape can be effectively prevented. However, since the bonding force based on ultrasonic bonding is weak, the bonding material 114 is relatively easy to peel off from the chip 102. Therefore, after bonding, when only the chip 102 is lifted while the transfer sheet 110 is sucked by the stage 12, as Figure 7 shown, there is a case where a part of the bonding material 114 remains on the release sheet 112 and the bonding material 114 cannot be properly transferred to the chip 102.

[0068] Therefore, in this example, in order to prevent the notch of the bonding material 114, the suction of the transfer sheet 110 based on the sheet suction source 26 is released during at least a part of the rising process of the chip 102. Specifically, the controller 16 stops the ultrasonic vibration after the bonding material 114 and the chip 102 are ultrasonically bonded, and releases the suction of the transfer sheet 110 based on the sheet suction source 26 (S20). Then, as Figure 2 shown in the middle part of, the controller 16 keeps the state of releasing the suction of the transfer sheet 110 and raises the chip 102 together with the suction tool 30 (S22). By releasing the suction force, the release sheet 112 is easily lifted. As a result, as Figure 2 shown in the middle part of, the release sheet 112 is not forcibly peeled off from the bonding material 114, and the release sheet 112 is also stretched upward together with the bonding material 114.

[0069] In the above state, if the chip 102 is further raised, the release sheet 112 peels off from the bonding material 114. The peeling occurs slowly from the end of the bonding material 114, so it is not easy to apply an excessive force to the bonding material 114, and it is not easy to generate a notch in the bonding material 114.

[0070] Then, if the chip 102 reaches a predetermined restart height Hd (Yes in S24), the controller 16 restarts the suction of the transfer sheet 110 based on the sheet suction source 26 (S26). As the suction restarts, as Figure 2As shown in the lower part of , the transfer sheet 110 is attracted to the stage 12. Then, thereby, the release sheet 112 is peeled off from the bonding material 114. Here, at the time point when the suction restarts, the peeling of the release sheet 112 starts at the end of the bonding material 114. Therefore, even when the suction restarts and the release sheet 112 is peeled off, it is not easy to apply a load to the bonding material 114, and it is not easy to generate a notch in the bonding material 114. As a result, the bonding material 114 can be transferred to the chip 102 well.

[0071] Then, the controller 16 drives the tool head 14 to transfer the transferred chip to a specified position. And, when there is a next chip 102 to be transferred (Yes in S28), the controller 16 repeats the processes after step S14 after replacing the chip held by the suction tool 30 (S30). On the other hand, if the transfer of all the chips 102 is completed, the process ends.

[0072] As is clear from the above description, according to this example, during the rising process of the chip 102, by temporarily releasing the suction of the transfer sheet 110, it is possible to prevent a notch in the bonding material 114 and transfer the bonding material 114 to the chip 102 well. In addition, since the bonding material 114 is bonded to the chip 102 by ultrasonic bonding, it is possible to effectively prevent the rounded shape at the corner of the bonding material 114.

[0073] In addition, the restart height Hd can be determined in advance through experiments or simulations. The restart height Hd can always be a fixed value, or can be a variable value that changes according to conditions. For example, the restart height Hd can also be changed according to at least one of the type of the transfer sheet 110 and the type of the chip 102. For example, the larger the size of the chip 102, the higher the restart height Hd can be increased. In addition, the restart height Hd can be changed according to the difference in the thickness or material of the transfer sheet 110. Furthermore, the restart height Hd can also be changed according to the position of the transfer area transferred to the chip 102 within the transfer sheet 110. For example, the closer the transfer area is to the constraint position by the jig 24, that is, the closer to the end of the transfer sheet 110, the lower the restart height Hd can be.

[0074] Furthermore, the restart height Hd can be changed according to the recent transfer quality. That is, as Figure 3As shown, generally, the transfer process of the bonding material 114 is sequentially performed on a plurality of chips 102. The controller 16 can periodically or randomly monitor the transfer quality of the processed chips 102, and change the restart height Hd in the subsequent transfer process according to the quality result. For example, a specified height H1 is set as the restart height Hd (i.e., Hd = H1). When a notch in the transferred bonding material 114 occurs, the controller 16 increases the current restart height Hd by a preset adjustment amount ΔH in the subsequent transfer process, and sets it to Hd = H1 + ΔH. In the case where a notch in the bonding material 114 still occurs even when the transfer process is performed with the new restart height Hd = H1 + ΔH, this time, the restart height Hd is decreased by the adjustment amount ΔH from the height before the increase, and set to Hd = H1 - ΔH. Thereafter, while gradually increasing the adjustment amount ΔH, the most suitable restart height Hd can be explored until no notch in the bonding material 114 occurs. By adopting the above structure, even if the peeling behavior of the release sheet 112 changes due to temperature, humidity, etc., the bonding material 114 can be properly transferred.

[0075] Furthermore, when raising the suction tool 30, the chip 102 can be tilted together with the suction tool 30. For example, as Figure 4 shown, a swing mechanism 48 can be provided that swings the suction tool 30 around a swing axis 46 extending in the horizontal direction. And, during the process of raising the chip 102 or after the raising is completed, the chip 102 can be tilted together with the suction tool 30. By adopting the above structure, since the release sheet 112 can be peeled off more smoothly, the notch in the bonding material 114 can be more effectively prevented.

[0076] In addition, the structures described so far are just examples and can be appropriately changed. For example, in the description so far, the suction of the transfer sheet 110 is restarted according to the height of the chip 102. However, the time point for restarting the suction can be determined based on other parameters. For example, a load sensor for detecting the load acting on the suction tool 30 can be provided on the tool head 14, and the time point for restarting the suction can be determined based on the detected load detected by the load sensor. For example, it can be speculated that during the process of raising the chip 102, if the peeling of the release sheet 112 starts, the load acting on the suction tool 30 will drop sharply. Therefore, during the process of raising the chip 102, the suction of the transfer sheet 110 can be restarted at the time point when the load changes sharply.

[0077] In addition, in the description so far, only one suction system for the transfer sheet 110 is provided, but multiple suction systems can also be provided. For example, as Figure 5As shown in the upper section, the carrier 12 may also have multiple suction paths 50a to 50f for each area. In the case, multiple switching valves 52a to 52f are provided, which switch the connection state between the multiple suction paths 50a to 50f and the sheet suction source 26. The controller 16 can switch the opening / closing of the switching valves 52a to 52f according to the status of the transfer process. For example, consider the case where the bonding material 114 of a certain area Ac is transferred to the chip 102. In the case, when the chip 102 is raised after the transfer is completed, the valves 52b to 52d corresponding to the area Ac and the surrounding areas Ab and Ad are closed, and the valves 52a, 52e, and 52f corresponding to the other areas Aa, Ae, and Af can be opened.

[0078] With the above configuration, suction is released only in the regions Ab to Ad within a certain range from the transfer region, while sheet suction continues in the other regions Aa, Ae, and Af. Thus, the bonding material 114 can be lifted up under the same conditions in any region.

[0079] That is, when the suction of the entire surface of the transfer sheet 110 is released, Figure 5 As shown in the lower section of FIG. 2 , the inclination of the release sheet 112 lifted together with the bonding material 114 and the form of the release sheet 112 peeling off from the bonding material 114 are different depending on the distance from the bonding material 114 to the clamp 24. On the other hand, as described above, when the suction of the transfer sheet 110 is partially released, the sheet suction position becomes the sheet restraint position. Therefore, when the suction of the transfer sheet 110 is partially released, the distance from the transfer area to the sheet restraint position can be always kept constant. As a result, the inclination of the release sheet 112 lifted together with the bonding material 114 and the form of the release sheet 112 peeling off can be always kept constant.

[0080] In addition, so far, as long as the suction and suction release of the transfer sheet 110 are switched in conjunction with the movement of the suction tool 30, the switching time point of the suction state can be appropriately changed. For example, in the above description, the suction of the transfer sheet 110 is released before the chip 102 rises. However, the suction of the transfer sheet 110 can also be released after the chip 102 starts to rise. In addition, the bonding material 114 is not limited to ultrasonic bonding, and can also be bonded to the chip 102 by other bonding methods. For example, as long as the problem of the circular shape can be avoided, the bonding material 114 can also be thermally eutectic bonded to the chip 102.

[0081] Furthermore, the suction tool 30 has been described so far as to move relative to the transfer sheet 110 placed on the stage 12. The suction tool 30 may move relative to the transfer sheet 110, and for example, the stage 12 may be raised or lowered relative to the suction tool 30.

[0082] Furthermore, the tension on the transfer sheet 110 may be changed in conjunction with the separation of the suction tool 30 from the release sheet 112 instead of the suction force on the transfer sheet 110. For example, the tension on the transfer sheet 110 may be adjusted in conjunction with the separation of the suction tool 30 from the release sheet 112 by changing the holding force of the clamp 24 or changing the position of the clamp.

Claims

1. A joint body manufacturing device, characterized in that: include: A carrier, on which a transfer sheet formed by laminating a release sheet and a bonding material is placed, and the transfer sheet is held by suction; a tool head having a tool for holding the chip; and Controller, The controller is configured as follows: After the tool is moved relative to the transfer sheet and the held chip is brought into contact with the bonding material for bonding, the tool is separated from the release sheet. The suction force of the transfer sheet by the stage or the tension of the transfer sheet is adjusted in conjunction with the separation of the tool.

2. The joint body manufacturing device according to claim 1, characterized in that: The controller is configured to, after the tool contacts the bonding material, raise the tool together with the chip in a state where the suction of the transfer sheet by the stage is released, and then restart the suction of the transfer sheet.

3. The joint body manufacturing device according to claim 2, characterized in that: The controller restarts the suction by the stage when the chip reaches a predetermined restart height.

4. The joint body manufacturing device according to claim 3, characterized in that: The restart height is a variable value that changes according to at least one of the type of the chip and the position of the transfer area transferred to the chip in the transfer sheet.

5. The joined body manufacturing apparatus according to any one of claims 1 to 4, characterized in that: The stage is capable of partially switching the suction state of the transfer sheet, The controller is configured to release the suction of the transfer sheet only within a certain range from a transfer region to be transferred to the chip after the bonding of the bonding material.

6. The joined body manufacturing apparatus according to any one of claims 1 to 4, characterized in that: The tool head has a vibration source for applying ultrasonic vibration to the chip, The controller is further configured to apply ultrasonic vibration to the chip when the chip is pushed against the bonding material.

7. A method for manufacturing a joint body, which is a method for manufacturing a joint body, characterized in that: The transfer sheet formed by laminating the release sheet and the bonding material is sucked and held by the stage. The tool holding the chip is moved to push the chip against the bonding material, thereby bonding the bonding material to the chip. The suction and release of the transfer sheet by the stage are switched in conjunction with the movement of the tool.

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