JP2013179208A - Die bonder and bonding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a die bonder or a bonding method with high reliability, capable of reliably mounting a die on an intermediate stage and reliably picking up it from the intermediate stage.SOLUTION: A die is picked up from a wafer by a pickup head, mounted on the intermediate stage, picked up by a bonding head from the intermediate stage and bonded to a substrate or the die already bonded, and when the die is mounted on the intermediate stage, the intermediate stage is lowered so as to buffer load due to the mounting.

Description

  The present invention relates to a die bonder and a bonding method, and more particularly to a highly reliable die bonder and a bonding method capable of reliably mounting a die.

A part of the process of assembling a package by mounting a die (semiconductor chip) (hereinafter simply referred to as a die) on a work such as a wiring board or a lead frame; There is a bonding process in which the divided dies are picked up from the wafer and stacked on a die that is mounted on a substrate or already bonded.
As a method of performing the bonding process, a die picked up from a wafer is once placed on a component placement table (intermediate stage), and then a die is picked up again from the component placement table by a bonding head, and bonded to a substrate that has been transported (Patent Document 1).

  When picked up from the wafer, the die is picked up together with a film to which an adhesive material called DAF (die attach film) is attached, and placed on the intermediate stage with the DAF facing down.

JP 2009-246285 A

  However, DAF is mainly a thermosetting type that is cured by heat and load. Depending on the load applied to the intermediate stage by the pickup head when the die picked up from the wafer is placed on the intermediate stage, the DAF is the intermediate stage. It will stick to. Furthermore, in recent years, DAF has been improved so that it can be cured at a low load and a low temperature in order to reduce stress during die mounting, and has become easier to stick to an intermediate stage. As a result, there is an increased possibility of a die pick-up mistake from the intermediate stage by the bonding head.

  In addition, with the recent further thinning of the die, there is an increased possibility of damaging the die depending on the load when the die is placed on the intermediate stage.

  Accordingly, an object of the present invention is to provide a highly reliable die bonder or bonding method capable of reliably placing a die on an intermediate stage and reliably picking up from the intermediate stage.

In order to achieve the above object, the present invention has at least the following features.
The present invention provides a die supply unit that holds a wafer, a pickup head that picks up a die from the wafer and places the die on an intermediate stage, an intermediate stage unit having the intermediate stage, and the die from the intermediate stage. A bonding head that picks up and bonds to the substrate or the bonded die, and an intermediate stage integrated structure that moves up and down integrally with the intermediate stage, and holds the load on the intermediate stage at the time of placement as described above. A first feature is that a load buffer mechanism for releasing the load is provided in the intermediate stage portion so as not to be applied.

  The present invention also provides a pickup step of picking up a die from a wafer with a pickup head and placing the die on an intermediate stage, and picking up the die from the intermediate stage with a bonding head on the substrate or the already-bonded die. A bonding head step for bonding; and a step of lowering the intermediate stage so as to buffer the load due to the placement when the die is placed on the intermediate stage. Features.

  Further, according to the present invention, the load buffering mechanism includes: a base that fixes the load buffering mechanism to the die bonder; load load holding means that holds the load load; the intermediate stage integrated structure; and the base. And a linear motion guide provided between them to linearly move the intermediate stage in the ascending / descending direction.

In addition, the present invention is characterized in that it has an integrated structure support portion for supporting the intermediate stage integrated structure.
Further, the present invention provides the load load holding means, wherein the intermediate stage integrated structure or the air cylinder provided between the integrated structure support portion and the base and the load load are held so as to hold the load load. A fifth feature is that it has an air supply regulator for controlling the air pressure to the air cylinder and an air supply source for supplying air to the air cylinder.

  In the present invention, the load load holding means may be configured so that the intermediate stage integrated structure or the linear structure motor provided between the integrated structure supporting portion and the base and the load load are held. A sixth feature is that the linear motor control unit controls the torque of the linear motor.

Further, according to the present invention, the load load holding means is provided between the intermediate stage integrated structure or the integrated structure supporting portion and the base, and has a constant tension so as to hold the intermediate stage integrated structure. The seventh feature is that it has a constant tension device that pushes up at the same time.
The eighth feature of the present invention is that the load buffering mechanism is provided on a lower side portion or a lower portion of the intermediate stage.

  Therefore, according to the present invention, it is possible to provide a highly reliable die bonder or bonding method capable of reliably placing a die on an intermediate stage and reliably picking up from the intermediate stage.

It is a schematic top view of the die bonder which is one Embodiment of this invention. It is a figure explaining operation | movement of a pick-up head and a bonding head when it sees from the arrow A direction in FIG. It is a schematic sectional drawing which shows the principal part of the die | dye supply part which is one Embodiment of this invention. It is the schematic which shows the 1st Example of the load buffer mechanism which is the characteristics of this embodiment. FIG. 5 is a view of the intermediate stage portion shown in FIG. 4 as viewed from the direction of arrow B. It is the schematic which shows the 2nd Example of the load buffer mechanism which is the characteristics of this embodiment. It is the schematic which shows the 3rd Example of the load buffer mechanism which is the characteristics of this embodiment. It is the schematic which shows the 4th Example of the load buffer mechanism which is the characteristics of this embodiment. It is a figure which shows the mounting operation | movement flow in Example 1 thru | or 4.

  Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic top view of a die bonder 10 according to an embodiment of the present invention. FIG. 2 is a diagram for explaining the operation of the pickup head 21 and the bonding head 41 when viewed from the direction of arrow A in FIG.
The die bonder 10 is roughly divided into a die supply unit 1 that supplies a die D to be mounted on the substrate P, a pickup unit 2 that picks up a die from the die supply unit 1, and a picked-up die D is placed once in the middle. An intermediate stage unit 3 having an intermediate stage 31, a bonding unit 4 that picks up the die D of the intermediate stage unit 3 and bonds it onto the substrate P or an already bonded die, and a conveyance unit that conveys the substrate P to a mounting position 5. A substrate supply unit 6K that supplies the substrate P to the transport unit 5, a substrate carry-out unit 6H that receives the mounted substrate P, and a control unit 7 that monitors and controls the operation of each unit.

  First, the die supply unit 1 includes a wafer holding table 12 that holds the wafer 11 and a push-up unit 13 indicated by a dotted line that pushes the die D up from the wafer 11. The die supply unit 1 is moved in the XY direction by a driving unit (not shown), and the die D to be picked up is moved to the position of the push-up unit 13.

  The pickup unit 2 has a collet 22 (see also FIG. 2) that sucks and holds the die D pushed up by the push-up unit 13 at the tip, and picks up the die D and places it on the intermediate stage 31; A pickup head Y drive unit 23 for moving the pickup head 21 in the Y direction. The pickup head 21 has driving units (not shown) that move the collet 22 up and down, rotate, and move in the X direction.

  The intermediate stage unit 3 includes an intermediate stage 31 on which the die D is temporarily placed, a stage recognition camera 32 for recognizing the die D on the intermediate stage 31, and a load buffer having features of the present embodiment described later. And a mechanism 8.

  The bonding unit 4 has the same structure as the pickup head, picks up the die D from the intermediate stage 31 and bonds it to the substrate P that has been transported, and a Y drive unit that moves the bonding head 41 in the Y direction. 43, and a substrate recognition camera 44 that captures an image of a position recognition mark (not shown) of the transported substrate P and recognizes the bonding position of the die D to be bonded.

  With such a configuration, the bonding head 41 corrects the pickup position / orientation based on the imaging data of the stage recognition camera 32, picks up the die D from the intermediate stage 31, and the substrate based on the imaging data of the substrate recognition camera 44. Bond die D to P.

  The transport unit 5 includes a substrate transport pallet 51 on which one or a plurality of substrates (four in FIG. 1) are placed, and a pallet rail 52 on which the substrate transport pallet 51 moves, and is provided in parallel. It has the 1st, 2nd conveyance part of the same structure. The substrate transfer pallet 51 is moved by driving a nut (not shown) provided on the substrate transfer pallet 51 with a ball screw (not shown) provided along the pallet rail 52.

  With such a configuration, the substrate transport pallet 51 has the substrate placed thereon by the substrate supply unit 6K, moves to the bonding position along the pallet rail 52, moves to the post-bonding substrate unloading unit 6H, and the substrate unloading unit 6H. The substrate P is handed over. The first and second transfer units are driven independently of each other, and while the die D is being bonded to the substrate P placed on one substrate transfer pallet 51, the other substrate transfer pallet 51 carries out the substrate P. Returning to the substrate supply unit 6K, preparations such as placing a new substrate P are made.

  FIG. 3 is a schematic cross-sectional view showing the main part of the die supply unit 1. As shown in FIG. 3, the die supply unit 1 includes an expand ring 15 that holds the wafer ring 14, a support ring 17 that horizontally positions the dicing tape 16 that is held by the wafer ring 14 and has a plurality of dies D adhered thereto, And a push-up unit 13 which is disposed inside the support ring 17 and pushes the die D upward. The push-up unit 13 is moved in the vertical direction by a driving mechanism (not shown), and the die supply unit 1 is moved in the horizontal direction.

The die supply unit 1 lowers the expanding ring 15 holding the wafer ring 14 when the die D is pushed up. As a result, the dicing tape 16 held on the wafer ring 14 is stretched to widen the distance between the dies D, and the push-up unit 13 pushes up the die D from below the die, thereby improving the pick-up property of the die D. As the thickness is reduced, the adhesive is changed from a liquid to a film, and a film-like adhesive material called a die attach film DAF is attached between the wafer and the dicing tape 16. In the wafer having the die attach film DAF, dicing is performed on the wafer and the die attach film DAF.
Therefore, when the die D is picked up from the wafer, the die attach film DAF adhered to the wafer is peeled off together with the die D and the dicing tape 16. This die attach film DAF brings about the problems already described.

  Therefore, in the present embodiment, when the load of the intermediate stage integrated structure that moves integrally with the intermediate stage 31 is held and the die D is placed on the intermediate stage 31 by the pickup head 21, the intermediate stage, that is, the die attach film A load buffer mechanism 8 for releasing the load is provided in the intermediate stage unit 3 so that the DAF and the die D are not loaded with a predetermined load or more.

Example 1
FIG. 4 is a schematic view showing a first example 8A of the load buffering mechanism 8 which is a feature of the present embodiment. FIG. 5 is a view of the intermediate stage portion 3 shown in FIG.
In addition to the intermediate stage 31 and the stage recognition camera 32 shown in FIGS. 1 and 2, the intermediate stage unit 3 includes the load buffering mechanism 8 </ b> A according to the first embodiment and a suction mechanism 33 that holds the die D on the intermediate stage 31. .

  The load buffering mechanism 8A constitutes an air cylinder holding means 81A that is a first embodiment of the load load holding means 81 that holds the load of the intermediate stage integrated structure that moves up and down integrally with the intermediate stage 31, and an air cylinder holding means 81A. A linear motion guide 82 provided on both sides of the air cylinder 81e that guides the intermediate stage 31 to perform a linear motion, a base 85 fixed to the fixed frame of the die bonder 10, and an intermediate stage integrated structure are supported. And an integrated structure support portion 86 for transmitting the operation of the load load holding means 81A to the intermediate stage 31.

The air cylinder holding means 81A is provided between the base 85 and the integrated structure support portion 86, and includes an air cylinder 81e having a cylinder rod 81r, an air supply source 83 for supplying air to the air cylinder 81e, and an intermediate stage. It has an air supply regulator 84 for controlling the air pressure to the air cylinder 81e so as to maintain an integrated structure.
The linear motion guide 82 has a slider 82s fixed to the intermediate stage 31 and a rear guide 82g on which the slider slides.

  The suction mechanism 33 includes a plurality of suction holes 33h provided in the intermediate stage 31, a suction source 33g for sucking air in the suction holes 33h, a connecting portion 33r for connecting the suction source 33g and the suction holes 33h, It has a concentrating part 33s for condensing air from the suction hole 33h to the connecting part 33r.

  In the first embodiment, since the aggregation portion 33 s is provided across the front surface of the lower surface of the intermediate stage 31, the load buffering mechanism 8 </ b> A is provided on the lower side portion shifted from the lower portion of the intermediate stage 31. However, by providing a hole through which the slider 82s and the cylinder rod 81r of the air cylinder 81e pass through the aggregation portion 33s, the load buffer mechanism 8A is supported by supporting the lower surface side of the intermediate stage 31 or directly supporting the suction mechanism 33. It is also possible to provide it below the intermediate stage 31. In this case, it is not necessary to provide the integrated structure support portion 86 by directly supporting the intermediate stage 31 or the suction mechanism 33.

  With such a configuration, when the die D is placed on the intermediate stage 31 by the pickup head 21, a constant load is held by the air supply regulator 84 when the load applied to the intermediate stage 31 exceeds a predetermined load. The intermediate stage 31 is lowered. As a result, the load applied to the die attach film DAF and the die D can be avoided so as not to exceed a predetermined load.

  According to the first embodiment described above, the load buffer mechanism 8A is provided to prevent the die attach film DAF from being cured and the die attach film DAF from sticking to the intermediate stage 31 due to the load applied to the intermediate stage 31. As a result, the die D can be prevented from being damaged.

  Accordingly, the predetermined load is set to a smaller one of a load that does not cure the die attach film DAF and a load that does not damage the die D. For example, the value of the predetermined load is 0.2N.

It is necessary for the load buffer mechanism 8A to lower the intermediate stage 31 in response to the predetermined load. For this purpose, it is necessary to make the movement resistance force when the intermediate stage 31 descends below the predetermined load. For example, the total of the friction resistance of the cylinder rod 81r and the cylinder rod seal portion of the load holding air cylinder 81e and the movement resistance of the linear motion guide 82 is configured to be less than the predetermined load, for example, 0.2N. If the movement resistance of the linear motion guide 82 can be ignored, the friction resistance between the cylinder rod 81r and the cylinder rod seal portion is configured to be less than the predetermined load.
The air supply regulator 84 is required to have a minimum control pressure performance less than the movement resistance.

(Example 2)
FIG. 6 is a schematic diagram illustrating a second example 8B of the load buffering mechanism 8 which is a feature of the present embodiment, and corresponds to FIG. The difference from the first embodiment of the load buffering mechanism 8B of the second embodiment is that a so-called linear motor 81B is used instead of the cylinder as the load load holding means 81, and the load load of the portion that moves the linear motor integrally with the intermediate stage 31 is adjusted. The torque control is performed so that the torque is maintained. Other points are the same as in the first embodiment. In the embodiment, the torque control is performed by the control unit 7 shown in FIG.

  The linear motor 81B is fixed to the integrated structure support portion 86, and a mover portion 81s having a mover on a cylindrical outer surface and a base 85 is fixed to the surface of the hole through which the mover moves. And a stator portion 81k provided. The fixing of the movable part 81s and the stator part 81k may be the reverse of the above.

  In the second embodiment, the same effect as that of the first embodiment can be obtained.

Example 3
FIG. 7 is a schematic diagram illustrating a third example 8C of the load buffering mechanism 8 which is a feature of the present embodiment, and corresponds to FIG. The difference from the first embodiment of the load buffering mechanism 8C of the third embodiment is that a constant tension device 81C is used as the load load holding means 81 instead of the cylinder. Other points are the same as in the first embodiment.

  The constant tension device 81C has a constant tension spring 81b that pushes up the intermediate stage 31, that is, the integrated structure support portion 86 to support the intermediate stage integrated structure portion. In this embodiment, the rod 81d is pushed up by two constant tension springs 81b to support the load of the intermediate stage integrated structure.

  Also in Example 3, the same effect as Example 1 can be produced.

  In Examples 1 to 3, the linear motion guides 82 are provided on both sides of the load load holding means 81. However, the linear motion guide 82 is provided on one side and the support area of the integrated structure support portion 86 of the load load holding means 81 is expanded or provided on both sides, and the linear motion guide 82 is provided at three or more locations. The intermediate stage 31 may be held stably.

Example 4
FIG. 8 is a schematic diagram illustrating a fourth example 8D of the load cushioning mechanism 8 which is a feature of the present embodiment, and corresponds to FIG. The load buffer mechanism 8D of the fourth embodiment has an air cylinder holding means 81A as in the first embodiment. The difference from the first embodiment is that, in the first embodiment, the air cylinder 81e is provided on the center side and the linear motion guides 82 are provided on both sides thereof, whereas in the fourth embodiment, the linear motion guide is provided on the central side. The air cylinder 81e is provided on both sides. Other points are the same as in the first embodiment. Similarly, in the second or third embodiment, the linear motion guide may be provided on the center side, and the load load holding means 81 may be provided on both sides thereof.

  In the fourth embodiment, the same effects as in the first to third embodiments can be obtained.

FIG. 9 is a diagram illustrating a mounting operation flow according to the first to fourth embodiments. The mounting operation flow will be described below with reference to FIG.
First, the pick-up head 21 picks up the die D pushed up by the push-up unit 13 by sucking it with the collet 22 (step 1) and places it on the intermediate stage 31 (step 2). The pickup head 21 returns to pick up the next die on which the die D is placed. FIG. 2 shows this state.

  Next, when the die D is placed on the intermediate stage 31, it is determined whether the placement load by the pickup head 21 is equal to or greater than the predetermined load described in the first embodiment (step 3). If the load is equal to or greater than the predetermined load, the intermediate stage 31 is retracted downward so as to reduce the mounting load (step 4), and the process proceeds to the next step 5. If it is less than the predetermined load, go directly to step 5.

  Next, the die D and the mounting state of the die are recognized by the stage recognition camera 32 (step 5). The bonding head 41 corrects the position / orientation based on the recognition result and picks up the die (step 6). Next, the bonding head 41 moves to the bonding position, and stacks (bonds) the die D adsorbed by the collet 42 to the substrate P or the already bonded die (step 7). 2 shows that the bonding head 41 faces the intermediate stage 31 in order to pick up the next die D after bonding the die D.

  Finally, it is determined whether a predetermined number of dies D have been bonded (step 8). If not bonded, the process returns to step 1, and if bonded, the process is terminated.

  Further, according to the first to fourth embodiments described above, when the die D is placed on the intermediate stage 31, the load buffer mechanism that releases the load so that the die attach film DAF and the die D are not loaded with a predetermined load or more. By providing 8 in the intermediate stage portion 3, a highly reliable die bonder or bonding method that can be reliably picked up from the intermediate stage 31 can be provided.

  Although the embodiments of the present invention have been described above, various alternatives, modifications, and variations can be made by those skilled in the art based on the above description, and the present invention is not limited to the various embodiments described above without departing from the spirit of the present invention. It encompasses alternatives, modifications or variations.

1: Die supply unit 2: Pickup unit 21: Pickup head 3: Intermediate stage unit 31: Intermediate stage 32: Stage recognition camera 33: Adsorption mechanism 4: Bonding unit 41: Bonding head 7: Control unit 8, 8A, 8B, 8C 8D: Load buffer mechanism 81: Load load holding means 81A: Air cylinder holding means 81B: Linear motor 81C: Constant tension device 82: Linear motion guide 85: Base 86: Integrated structure support 10: Die bonder 11: Wafer 13 : Push-up unit D: Die DAF: Die attach film P: Substrate

Claims (11)

A die supply unit for holding a wafer;
A pickup head that picks up a die from the wafer and places the die on an intermediate stage;
An intermediate stage having the intermediate stage;
A bonding head that picks up the die from the intermediate stage and bonds it onto a substrate or the already bonded die;
A load buffer mechanism that retains the load of the intermediate stage integrated structure that moves up and down integrally with the intermediate stage and releases the load to the intermediate stage so that the intermediate stage is not subjected to a load more than a predetermined amount at the time of placement is provided in the intermediate stage part. Established
Die bonder characterized by. The load buffer mechanism is
A base for fixing the load buffer mechanism to the die bonder;
Load load holding means for holding the load load;
A linear motion guide that is provided between the intermediate stage integrated structure and the base and linearly moves the intermediate stage in the up-and-down direction;
The die bonder according to claim 1, comprising:   The die bonder according to claim 2, further comprising an integrated structure support portion that supports the intermediate stage integrated structure. The load load holding means includes an air cylinder provided between the intermediate stage integrated structure and the base, and an air supply regulator for controlling the air pressure to the air cylinder so as to hold the load load. The die bonder according to claim 2, further comprising: an air supply source that supplies air to the air cylinder.   The load load holding means includes an air cylinder provided between the integrated structure support portion and the base, and an air supply regulator for controlling the air pressure to the air cylinder so as to hold the load load. The die bonder according to claim 3, further comprising: an air supply source that supplies air to the air cylinder.   The load load holding means includes a linear motor provided between the intermediate stage integrated structure and the base, and a linear motor control unit for controlling the torque of the linear motor so as to hold the load load. The die bonder according to claim 2, wherein the die bonder is provided.   The load load holding means includes: a linear motor provided between the integrated structure support portion and the base; and a linear motor control unit that controls the torque of the linear motor so as to hold the load load. The die bonder according to claim 3, wherein the die bonder is provided.   The load load holding means includes a constant tension device that is provided between the intermediate stage integrated structure and the base and is pushed up with a constant tension so as to hold the intermediate stage integrated structure. Item 3. The die bonder according to item 2.   The load load holding means includes a constant tension device that is provided between the integrated structure support portion and the base and is pushed up with a constant tension so as to hold the intermediate stage integrated structure. Item 4. The die bonder according to item 3.   The die bonder according to claim 1, wherein the load buffering mechanism is provided at a lower side portion or a lower portion of the intermediate stage. A pickup step of picking up a die from the wafer with a pickup head and placing the die on an intermediate stage;
A bonding head step of picking up the die from the intermediate stage with a bonding head and bonding onto the substrate or the already bonded die;
When the die is placed on the intermediate stage, the intermediate stage is lowered so as to buffer the load due to the placement;
A bonding method characterized by comprising:

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