Joint manufacturing apparatus and joint manufacturing method

Abstract

To provide a manufacturing device of a junction, capable of preferably transferring a joint material to a chip.SOLUTION: A manufacturing device of a junction 10 comprises: a stage 12 to which a transfer sheet 110 into which a release sheet 112 and a joint material 114 are laminated is mounted, and which sucks and holds the transfer sheet 110; and a tool head 14 that includes a suction tool 30 that holds a chip 102; and a controller 16. The controller 16 moves the suction tool 30 in a state where the chip 102 is held so as to press the chip 102 to the joint material 114, and thereby jointing the joint material 114 to the chip 102, and a suction and a suction cancellation of the transfer sheet 110 by the stage 12 can be switched so as to be linked to a movement of the suction tool 30.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present specification discloses a bonded body manufacturing apparatus and a bonded body manufacturing method for manufacturing a bonded body obtained by transferring a bonding material onto a chip. [Background Art]

[0002] In recent years, in order to bond chips to circuit boards, it has been proposed to use sintered bonding using nanoparticles or microparticles of a metal such as silver (Ag). In order to enable such sintered bonding, it has been proposed to previously transfer a bonding material made of a sintered material onto the lower surface of the chip.

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

[0004] [Patent Document 1] Japanese Unexamined Patent Publication No. 2020-056110 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] However, when the bonding between the chip and the bonding material is weak, part of the bonding material may peel off from the chip when the chip is lifted after the bonding process. In other words, there is a risk that a portion of the bonding material transferred to the chip may be missing.

[0006] Therefore, the present specification discloses a bonded body manufacturing apparatus and a bonded body manufacturing method capable of more favorably transferring a bonding material onto a chip. [Means for Solving the Problem]

[0007] The bonding apparatus disclosed herein comprises a transfer sheet on which a release sheet and a bonding material are laminated, a stage for suction holding the transfer sheet, a tool head having a tool for holding a chip, and a controller, wherein the controller is configured to move the tool relative to the transfer sheet to bring the held chip into contact with the bonding material and bond them, then move it away from the release sheet, and adjust the suction force of the transfer sheet by the stage or the tension of the transfer sheet in conjunction with the separation of the tool.

[0008] In this case, the controller may be configured to raise the tool together with the tip after the tool has made contact with the bonding material, with the suction of the transfer sheet by the stage released, and then restart the suction of the transfer sheet.

[0009] Furthermore, the controller may restart suction by the stage when the chip reaches a predetermined restart height.

[0010] In this case, the restart height may be a variable value that changes depending on at least one of the type of chip and the position of the transfer area to be transferred to the chip within the transfer sheet.

[0011] 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 the transfer area to be transferred to the chip after the bonding of the bonding material.

[0012] Furthermore, the tool head may have a vibration source that applies ultrasonic vibration to the tip, and the controller may be configured to further apply ultrasonic vibration to the tip at the timing when the tip is pressed against the bonding material.

[0013] The method for manufacturing a bonded body disclosed herein is characterized by holding a transfer sheet, on which a release sheet and a bonding material are laminated, by suction on a stage, moving a tool that holds the tip so as to press the tip against the bonding material, thereby bonding the bonding material to the tip, and switching between suction and release of the transfer sheet by the stage in conjunction with the movement of the tool. [Effects of the Invention]

[0014] The technology disclosed herein prevents excessive force from being applied to the bonding material bonded to the tip by switching the suction and release of the transfer sheet in conjunction with the movement of the tool and, consequently, the tip. As a result, chipping of the bonding material is effectively prevented, and the bonding material can be transferred to the tip more effectively. [Brief explanation of the drawing]

[0015] [Figure 1] This is a schematic diagram showing the configuration of a joint manufacturing apparatus. [Figure 2] This is a schematic diagram showing the manufacturing process of the jointed parts. [Figure 3] This is a flowchart showing the manufacturing process of the jointed parts. [Figure 4] This figure shows an example of another toolhead. [Figure 5] This figure shows an example of another stage. [Figure 6] This figure shows an example of a conventional transfer process. [Figure 7] This figure shows an example of chipping in the joining material. [Modes for carrying out the invention]

[0016] Hereinafter, the configuration of a bonded body manufacturing apparatus 10 will be described with reference to the drawings. Fig. 1 is a schematic diagram showing the configuration of the bonded body manufacturing apparatus 10. In Fig. 1, the dimensional ratio of each member is greatly changed from the actual dimensional ratio in order to ensure visibility. In particular, the thickness of the transfer sheet 110 relative to the size of the chip 102 is illustrated to be significantly larger than the actual thickness. In practice, for example, when one side of the chip 102 is several millimeters, the thickness of the transfer sheet 110 is several tens of micrometers, or around 100 micrometers.

[0017] The bonded body manufacturing apparatus 10 transfers the bonding material 114 onto the bottom surface of a semiconductor chip (hereinafter referred to as "chip 102") to obtain a bonded body 100 (see Fig. 2) in which the bonding material 114 is bonded to the chip 102. The bonded body manufacturing apparatus 10 includes a stage 12, a tool head 14, and a controller 16.

[0018] The stage 12 has the transfer sheet 110 placed thereon and sucks the transfer sheet 110. The transfer sheet 110 is a sheet in which a bonding material 114 and a release sheet 112 are laminated. The release sheet 112 is a sheet that carries the bonding material 114, and is made of resin, for example. The bonding material 114 is, for example, a thin film made of metal and transferred onto the chip 102. Such a bonding material 114 is, for example, a film-shaped sintered bonding composition containing at least conductive metal-containing sinterable particles and a binder component. The sinterable particles are particles that contain a conductive metal element and can be sintered. The sinterable particles are composed of, for example, gold, silver, copper, palladium, tin, nickel, and an alloy of two or more metals selected from the group thereof. Such a bonding material 114 may be pre-formed with cuts 115 corresponding to the shape of the chip 102 described later. For example, when the chip 102 is a rectangle of a predetermined size, cuts may be formed in a grid pattern in the bonding material 114 such that rectangles of the predetermined size are arranged.

[0019] A support layer 22 is provided on the upper surface of the stage 12, and the bonding material 114 is placed on this support layer 22. The support layer 22 is formed of a rigid material such as a metal such as stainless steel or aluminum, or ceramics. Further, a plurality of suction holes (not shown) are formed in the surface of the stage 12. These suction holes are fluidly connected to a sheet suction source 26. The sheet suction source 26 applies negative pressure to the transfer sheet 110 via the suction holes, and is, for example, a suction pump. By driving this sheet suction source 26, the transfer sheet 110 is suction-held on the upper surface of the stage 12.

[0020] The stage 12 is further provided with a clamp 24. The clamp 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 clamp 24 presses and fixes the right end and the left end of the transfer sheet 110 against the stage 12.

[0021] The tool head 14 includes a suction tool 30 that suction-holds the chip 102, and a moving mechanism (not shown) that moves the suction tool 30. The suction tool 30 can be moved in horizontal and vertical directions by the moving mechanism. A suction hole (not shown) is formed in the distal end surface of the suction tool 30. This suction hole is fluidly connected to a chip suction source 34. The chip suction source 34 applies 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 by the suction tool 30. Then, the chip 102 is conveyed 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 consequently the height of the chip 102, and transmits the detection result to the controller 16.

[0022] The tool head 14 further includes a vibration source 32. The vibration source 32 applies ultrasonic vibrations to the suction tool 30, and consequently to the tip 102 held by the suction tool 30. The vibration source 32 includes, for example, an ultrasonic vibration element and an AC power supply. The ultrasonic vibration element receives a drive signal, which is a voltage signal, and generates longitudinal vibrations. This ultrasonic vibration element has, for example, lead zirconate titanate (commonly known as PZT) that vibrates in response to an AC voltage, and is a bolt-tightened Langevin type transducer (commonly known as BLT or BL transducer) in which the PZT is sandwiched between metal blocks and tightened with screws (bolts) to apply pressure. The controller 16, described later, after grounding the tip 102 to the transfer sheet 110, drives the vibration source 32 to apply ultrasonic vibrations to the tip 102. Then, the bonding material 114 is ultrasonically bonded to the tip 102 by these ultrasonic vibrations.

[0023] The controller 16 controls the operation of each part of the joint manufacturing apparatus 10. For example, the controller 16 controls the movement of the suction tool 30, the ON / OFF status of the suction sources 26 and 34, and the ON / OFF status of the vibration source 32. Physically, the controller 16 is a computer having a processor 40 and memory 42. In Figure 1, the controller 16 is shown as a single computer, but the controller 16 may be configured by combining multiple physically separated computers.

[0024] Next, the manufacturing process of the bonded body 100 using the bonded body manufacturing apparatus 10 will be explained. Figure 2 is a schematic diagram showing the manufacturing process of the bonded body 100, and Figure 3 is a flowchart showing the manufacturing process. When manufacturing the bonded body 100 by transferring the bonding material 114 to the chip 102, first, the transfer sheet 110 is set on the stage 12 (S10). Then, the suction of the transfer sheet 110 by the sheet suction source 26 is started (S12).

[0025] The controller 16 uses the suction tool 30 to hold the tip 102 in place and moves the suction tool 30 to directly above the transfer area on the transfer sheet 110. Then, the controller 16 gradually lowers the tip 102 together with the suction tool 30 towards the transfer sheet 110 (S14). When the tip 102 makes contact with the transfer sheet 110 as a result of the descent (Yes in S16), the controller 16 applies pressure to the tip 102, pressing it against the bonding material 114 (S18). At the same time, the controller 16 drives the vibration source 32 to apply ultrasonic vibration to the tip 102 (S18). The upper part of Figure 2 shows this state. By applying ultrasonic vibration to the tip 102, the bonding material 114 is ultrasonically bonded to the tip 102, and thus transferred.

[0026] Once the bonding material 114 is bonded to the tip 102, the controller 16 then raises the suction tool 30 and moves the tip 102 (S22). At this time, the controller 16 switches between suctioning and releasing the transfer sheet 110 by the sheet suction source 26 in conjunction with the movement of the suction tool 30 (S20-S26). This will be explained in comparison with the conventional technology.

[0027] Conventionally, bonding material 114 was often bonded (i.e., transferred) using heat and pressure rather than ultrasound. That is, as shown in the upper part of Figure 6, the tip 102 was heated and pressurized while in contact with the bonding material 114. As a result, the bonding material 114 was thermally eutectic bonded to the tip 102. After bonding, the tip 102 was raised while the transfer sheet 110 was still attracted to the stage 12.

[0028] However, in the case of thermal eutectic bonding, as shown in the lower part of Figure 6, the heat easily causes rounded shapes (fillets) in the bonding material 114 bonded to the chip 102, where the corners are rounded off. Such rounded shapes can cause defects in the post-processing stages of semiconductor manufacturing.

[0029] Therefore, it is conceivable to bond the bonding material 114 ultrasonically instead of by thermal eutectic bonding. With ultrasonic bonding, the aforementioned round shape can be effectively prevented. However, because the bonding force by ultrasonic bonding is weak, the bonding material 114 peels off from the tip 102 relatively easily. For this reason, if the tip 102 is simply raised while the transfer sheet 110 is still sucked onto the stage 12 after bonding, as shown in Figure 7, some of the bonding material 114 may remain on the release sheet 112, and the bonding material 114 may not be properly transferred to the tip 102.

[0030] Therefore, in this example, in order to prevent chipping of the bonding material 114, the suction of the transfer sheet 110 by the sheet suction source 26 is released at least for a portion of the process of raising the tip 102. Specifically, after the bonding material 114 is ultrasonically bonded to the tip 102, the controller 16 stops the ultrasonic vibration and releases the suction of the transfer sheet 110 by the sheet suction source 26 (S20). Then, as shown in the middle of Figure 2, the controller 16 raises the tip 102 together with the suction tool 30 while the suction of the transfer sheet 110 is released (S22). With the suction force released, the release sheet 112 lifts up easily. As a result, as shown in the middle of Figure 2, the release sheet 112 is pulled upward together with the bonding material 114 without being forcibly peeled off.

[0031] In this state, if the tip 102 is raised further, the release sheet 112 will peel off from the bonding material 114. Since this peeling occurs gradually from the edge of the bonding material 114, excessive force is less likely to be applied to the bonding material 114, and chipping of the bonding material 114 is less likely to occur.

[0032] Subsequently, when the tip 102 reaches a predetermined restart height Hd (Yes in S24), the controller 16 restarts the suction of the transfer sheet 110 by the sheet suction source 26 (S26). With the restart of suction, the transfer sheet 110 is pulled towards the stage 12, as shown in the lower part of Figure 2. As a result, the release sheet 112 peels off from the bonding material 114. At the time of restart of suction, the peeling of the release sheet 112 has already begun at the edge of the bonding material 114. Therefore, even if the peeling of the release sheet 112 progresses after the restart of suction, the bonding material 114 is less likely to be subjected to stress, and chipping of the bonding material 114 is less likely to occur. As a result, the bonding material 114 can be transferred to the tip 102 well.

[0033] Subsequently, the controller 16 drives the tool head 14 to transport the transferred tip to a predetermined position. If there is another tip 102 to be transferred, the controller 16 replaces the tip held by the suction tool 30 (S30) and repeats the process from step S14 onward. Meanwhile, once the transfer of all tips 102 is complete, the process ends.

[0034] As is clear from the above explanation, in this example, by temporarily releasing the suction of the transfer sheet 110 during the upward movement of the tip 102, chipping of the bonding material 114 is prevented, and the bonding material 114 can be successfully transferred to the tip 102. Furthermore, since the bonding material 114 is bonded to the tip 102 by ultrasonic bonding, rounding of the corners of the bonding material 114 can be effectively prevented.

[0035] The restart height Hd may be determined in advance by experiment or simulation. This restart height Hd may always be a fixed value, or it may be a variable value that changes depending on the conditions. For example, the restart height Hd may be changed according to at least one of the type of transfer sheet 110 and the type of chip 102. For example, the larger the size of the chip 102, the higher the restart height Hd may be. The restart height Hd may also be changed according to the difference in thickness and material of the transfer sheet 110. Furthermore, the restart height Hd may also be changed according to the position of the transfer area to be transferred to the chip 102 within the transfer sheet 110. For example, the closer the transfer area is to the restrained position by the clamp 24, that is, the closer it is to the edge of the transfer sheet 110, the lower the restart height Hd may be.

[0036] Furthermore, the restart height Hd may be changed according to the most recent transfer quality. That is, as shown in Figure 3, the transfer process of the bonding material 114 is usually performed sequentially on multiple chips 102. The controller 16 periodically or randomly monitors the transfer quality of the chips 102 after processing, and may change the restart height Hd in subsequent transfer processes according to the quality results. For example, if a predetermined height H1 is set as the restart height Hd (i.e., Hd=H1), and chipping of the bonding material 114 occurs after transfer, the controller 16 will increase the current restart height Hd by a predetermined adjustment amount ΔH in subsequent transfer processes, so that Hd=H1+ΔH. If chipping of the bonding material 114 still occurs even after performing the transfer process with this new restart height Hd=H1+ΔH, the controller 16 will then decrease the restart height Hd by the adjustment amount ΔH from the height before the increase, so that Hd=H1-ΔH. Thereafter, the optimal restart height Hd may be searched for by gradually increasing the adjustment amount ΔH until no more chipping of the bonding material 114 occurs. With this configuration, the bonding material 114 can be properly transferred even if the peeling behavior of the release sheet 112 changes due to temperature, humidity, etc.

[0037] Furthermore, when raising the suction tool 30, the tip 102 may be tilted together with the suction tool 30. For example, as shown in Figure 4, a rocking mechanism 48 may be provided that rocks the suction tool 30 around a horizontally extending rocking axis 46 (see Figure 2). Then, during the process of raising the tip 102, or after the raising is complete, the tip 102 may be tilted together with the suction tool 30. With this configuration, the release sheet 112 can be peeled off more smoothly, and chipping of the bonding material 114 can be prevented more effectively.

[0038] Furthermore, the configuration described above is merely an example, and other configurations may be modified as appropriate, as long as the configuration described in claim 1 is met. For example, in the above description, suction of the transfer sheet 110 is restarted according to the height of the tip 102. However, the timing of restarting suction may be determined based on other parameters. For example, a load sensor that detects the load acting on the suction tool 30 may be provided on the tool head 14, and the timing of restarting suction may be determined based on the detected load detected by this load sensor. For example, it is presumed that when peeling of the release sheet 112 begins during the process of raising the tip 102, the load acting on the suction tool 30 decreases rapidly. Therefore, suction of the transfer sheet 110 may be restarted at the moment when the load changes rapidly during the process of raising the tip 102.

[0039] Furthermore, although the above explanation has assumed only one suction system for the transfer sheet 110, multiple suction systems may be provided. For example, as shown in the upper part of Figure 5, the stage 12 may have multiple suction paths 50a to 50f for each area. In this case, multiple switching valves 52a to 52f are provided to switch the communication state between the multiple suction paths 50a to 50f and the sheet suction source 26. The controller 16 may switch the opening / closing of the switching valves 52a to 52f depending on 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 this case, when raising the chip 102 after the transfer is complete, the valves 52b to 52d corresponding to area Ac and its surrounding areas Ab and Ad may be closed, while the valves 52a and 52f corresponding to other areas Aa, Ae, and Af may be opened.

[0040] With this configuration, suction is released only from areas Ab to Ad within a certain range from the transfer area, while sheet suction continues in the other areas Aa, Ae, and Af. This allows the bonding material 114 to be lifted under the same conditions in any area.

[0041] In other words, when the suction of the entire surface of the transfer sheet 110 is released, as shown in the lower part of Figure 5, the inclination of the release sheet 112 that lifts up together with the bonding material 114, and consequently the manner in which the release sheet 112 peels off from the bonding material 114, will differ 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 always be kept constant. As a result, the inclination of the release sheet 112 that lifts up together with the bonding material 114, and consequently the manner in which the release sheet 112 peels off, can always be kept constant.

[0042] Furthermore, as long as the suction and release of the transfer sheet 110 are switched in conjunction with the movement of the suction tool 30, the timing of the suction state switching may be changed as appropriate. For example, in the above description, the suction of the transfer sheet 110 is released prior to the upward movement of the tip 102. However, the suction of the transfer sheet 110 may be released after the tip 102 has started to rise. Also, the bonding material 114 may be bonded to the tip 102 by methods other than ultrasonic bonding. For example, the bonding material 114 may be thermally eutectic bonded to the tip 102 if it is possible to avoid the problem of a round shape.

[0043] Furthermore, it has been explained that the suction tool 30 moves relative to the transfer sheet 110 placed on the stage 12. However, the suction tool 30 only needs to move relative to the transfer sheet 110, and for example, the stage 12 may be configured to move up and down relative to the suction tool 30.

[0044] Furthermore, instead of changing the suction force on the transfer sheet 110, 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. For example, the tension on the transfer sheet 110 may be adjusted by changing the holding force of the clamp 24 or changing the clamp position in conjunction with the separation of the suction tool 30 from the release sheet 112. [Explanation of Symbols]

[0045] 10 Joint manufacturing equipment, 12 Stage, 14 Tool head, 16 Controller, 22 Support layer, 24 Clamp, 26 Sheet suction source, 30 Suction tool, 32 Vibration source, 34 Tip suction source, 36 Height sensor, 40 Processor, 42 Memory, 46 Oscillating axis, 48 ​​Oscillating mechanism, 100 Joint, 102 Tip, 110 Transfer sheet, 112 Release sheet, 114 Bonding material, 115 Cut, HD Restart height.

Claims

1. A transfer sheet, on which a release sheet and a bonding material are laminated, is placed, and a stage is provided for suction holding the transfer sheet. A tool head having a tool for holding the tip, Controller and The controller is equipped with, The tool is moved relative to the transfer sheet, and the held chip is brought into contact with the bonding material to bond it, and then 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. The controller, after the tool has made contact with the bonding material, releases the suction of the transfer sheet by the stage, raises the tool together with the tip, and then resumes the suction of the transfer sheet. A joint manufacturing apparatus characterized by being configured in such a way.

2. The apparatus for manufacturing a bonded body according to claim 1, The assembly manufacturing apparatus is characterized in that the controller restarts suction by the stage when the chip reaches a predetermined restart height.

3. The apparatus for manufacturing a bonded body according to claim 2, The assembly manufacturing apparatus is characterized in that the restart height is a variable value that changes according to at least one of the type of chip and the position of the transfer area to be transferred to the chip within the transfer sheet.

4. A joint manufacturing apparatus according to any one of claims 1 to 3, The aforementioned stage is capable of partially switching the suction state of the transfer sheet, The bonded body manufacturing apparatus is characterized in that the controller is configured to release the suction of the transfer sheet only within a certain range from the transfer area that is transferred to the chip after the bonding of the bonding material.

5. A joint manufacturing apparatus according to any one of claims 1 to 3, The tool head has a vibration source that applies ultrasonic vibrations to the tip. The bonding apparatus is characterized in that the controller is further configured to apply ultrasonic vibration to the chip at the timing when the chip is pressed against the bonding material.

6. A method for manufacturing a joint, The transfer sheet, which consists of a release sheet and a bonding material laminated together, is held in place by suction on the stage. By moving the tool while holding the tip so that the tip is pressed against the bonding material, the bonding material is bonded to the tip. The stage switches between sucking and releasing the transfer sheet in conjunction with the movement of the tool. After the tool makes contact with the bonding material, the tool and tip are raised with the stage's suction of the transfer sheet released, and then the suction of the transfer sheet is restarted. A method for manufacturing a bonded body characterized by the following features.

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