JP4298640B2 - Collet for die bonder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a collet for die bonder which can sufficiently be mounted on a substrate by eliminating influence of void residual by a very thin die whose thickness is about 50 &mu;m. <P>SOLUTION: The collet 10 is provided with a rectangular elastic absorption member 20 made from rubber, and a holder 30 pressurizing and holding the absorption member 20 so that it is embraced from a side 20b. Vacuum absorption holes 21 are made only at peripheries N except for the center M of the lower absorption face 20a of the absorption member 20, and the thin die 4 is absorbed. Thus, the die 4 is mounted on the substrate 40 in a state where the center M of the absorption face 20a and the center of the die 4 are protrusively deformed downward in a convex spherical face shape. <P>COPYRIGHT: (C)2006,JPO&amp;NCIPI

Description

  The present invention relates to a die bonder collet for adsorbing a die such as a semiconductor chip (pellet) by vacuum suction and mounting it on a substrate such as a lead frame.

  The die-binder collet that sucks and sucks the thin die on the adhesive tape, peels it off the adhesive tape, and thermocompression-bonds it onto a specific substrate via a thermosetting resin film. A plug-in type rubber collet that is inserted into and fixed to an adsorbing member is common. This rubber collet was developed in response to the increasingly thinner die of recent years, and has a rim type rubber collet with protrusions on the periphery of the adsorption surface of the elastic adsorption member (for example, see Patent Document 1) And the surface type rubber collet whose adsorption surface is a flat surface is marketed. For example, FIG. 10 shows an edge type rubber collet, and FIG. 11 shows a surface type rubber collet.

  The rubber collet of FIG. 10 includes an elastic adsorbing member 2 such as natural rubber or synthetic rubber, and a metal plug-in type holder 3. The adsorbing member 2 is a rectangular flat rubber component having a predetermined thickness with parallel upper and lower surfaces, and a holder 3 is connected to the upper surface side. The adsorbing member 2 integrally has a rectangular frame-shaped protruding edge 2a at the peripheral edge of the lower surface. A die suction recess 2b is formed inside the protrusion edge 2a. A bottomed insertion hole 2c is formed at the center of the upper surface of the suction member 2, and the holder 3 is inserted into the insertion hole 2c and fixed. A suction hole 2e penetrating vertically through the thin portion 2d is formed in the thin portion 2d between the top surface of the recess 2b and the bottom surface of the insertion hole 2c. The holder 3 has a hollow shaft portion 3a that is inserted into the insertion hole 2c, and a flange portion 3b that protrudes from a substantially middle portion of the hollow shaft portion 3a. The flange portion 3b is bonded and fixed to the upper surface of the adsorption member 2. The The hollow hole of the hollow shaft portion 3 a is a vacuum suction hole 3 c and communicates with the suction hole 2 e of the suction member 2.

For example, a thin die 4 as shown in FIG. The protrusion edge 2a abuts on the flat upper surface of the die 4, and the inside of the recess 2b is sucked by vacuum to suck the die 4. The rubber collet moves onto a substrate (not shown) while adsorbing the die 4 and mounts the die 4 on the substrate via an adhesive or a thermosetting resin film. Rubber collet of Figure 10, if the large die 4 for adsorbing the hardly thickness variation, favorably adsorbed without deforming the die by utilizing projections edge 2 a and recesses 2 b. However, if a very thin and die 4 are a thickness of 50μm as shown in FIG. 10, when the suction of the die 4 with an elastic suction member 2, the die 4 is deformed into a convex spherical upward is sucked into the recess 2 b To do. When this die 4 is thermocompression-bonded onto a substrate with a rubber collet, for example, via a thermosetting resin film, a gap is generated between the die 4 and the thermosetting resin film, and the substrate may remain as a void after mounting. is there. Such residual voids cause defects in the bonding between the die 4 and the substrate, and the residual voids explode during heat treatment when the die is resin-molded to manufacture a semiconductor device, causing defects such as separation of the joints. There is.

The surface type rubber collet shown in FIG. 11 solves such a problem. This rubber collet also includes an elastic adsorbing member 2 such as natural rubber or synthetic rubber and a metal holder 3. The adsorbing member 2 is a rectangular flat rubber component having a predetermined thickness with parallel upper and lower surfaces, and the same insertion type holder 3 as that shown in FIG. The lower surface of the suction member 2 is a flat suction surface 2f. The hollow shaft portion 3 a of the holder 3 is fitted into a bottomed insertion hole 2 c formed at the center of the upper surface of the suction member 2, and the flange portion 3 b is fixed to the upper surface of the suction member 2. The suction hole 2e formed in the thin portion 2d between the center portion of the suction surface 2f and the bottom surface of the insertion hole 2c and the vacuum suction hole 3c formed in the hollow shaft portion 3a of the holder 3 communicate with each other.
Japanese Patent Laying-Open No. 2004-87777 (FIG. 10)

  In the rubber collet of FIG. 11, the suction surface 2f of the suction member 2, which is a rubber component, is a flat surface, so that it can be sucked and sucked without greatly deforming a thin die. However, as shown in FIG. 12, for example, when the suction surface 2f is pressed against the ultrathin die 4 having a thickness of about 50 μm and vacuum suction is performed, the thin portion 2d at the center of the suction surface 2f becomes vacuum suction force. Due to the deformation, the central portion 4a of the die 4 is also deformed upward into a convex spherical shape. When this die 4 is thermocompression bonded onto a substrate with a rubber collet via a thermosetting resin film, a void is generated between the deformed center portion of the die 4 and the thermosetting resin film. In this case, the amount of voids generated at the center of the die is smaller than in the case of FIG. However, these voids cannot be eliminated even if the load at the time of chip thermocompression bonding is increased and may remain and cause a bonding failure at the center of the die 4.

  Further, in the rubber collet of FIG. 11, the hardness of the suction member 2 which is a rubber part is set high so that the thin-walled portion 2d is not easily deformed. For example, the rubber hardness is set to about JIS-A80. However, at present, it is difficult to avoid the occurrence of a void remaining defect due to deformation of the thin portion 2d during die suction. In addition, since the hardness of the adsorption member 2 is set to be high, it is difficult to make the die 4 adhere to the entire upper surface of the die 4 with a uniform force, and the die 4 is adsorbed by being inclined in the thickness direction and mounted on the substrate as it is. May cause problems.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a die bonder collet that can be mounted on a substrate or the like satisfactorily even without being affected by voids even with an extremely thin die.

The present invention includes a resilient suction member formed with vacuum suction holes in the periphery except for the central portion of the flat suction surface for sucking adsorb die to hold the resilient suction member is pressurized from the side of the elastic suction member The above object is achieved by a structure having a holder and a claw part that supports the holder so as to embrace a plurality of spaced apart parts on the side surface of the elastic adsorption member .

  Here, a thin work such as a semiconductor chip, a printed film piece, or a metal piece can be applied to the die. As the elastic adsorbing member, a block body having a thickness such as a rectangular, polygonal or circular shape of a natural rubber or a synthetic rubber having a flat adsorbing surface for adsorbing and adsorbing the flat upper surface of the die over the entire area can be applied. The vacuum suction holes formed only in the peripheral portion excluding the central portion of the suction surface of the elastic suction member are a plurality of circular holes having the same shape, a plurality of circular holes having different shapes, and a slit-like long hole. The holder is made of a hard material such as a metal, and pressurizes and holds the side surface of the thick elastic adsorption member. The suction surface of the elastic suction member before being held by the holder is a flat surface such as a rectangle or a circle. By pressing the side surface of the suction member with the holder, the suction member is compressed and the lower suction surface is convex. It can also be deformed into a spherical shape.

  When the die is sucked and sucked by the suction surface of the elastic suction member supported by the holder, the suction surface and the die are deformed as follows in the case of an extremely thin chip in which the die is easily deformed. By sucking the die through the suction holes at the periphery of the suction surface, the suction hole portion at the periphery of the suction surface is deformed in a compressing direction by the action of the die suction force. Deforms in the direction of compression. The deformation of the suction surface and the peripheral portion of each die is more noticeably performed than the deformation of the suction surface and the central portion of each die. As a result, the die adsorbed by the adsorbing member is deformed so that the central portion protrudes downward in a convex spherical shape, and is held as it is. Such deformation of the die can be performed more remarkably and reliably by pressing the side surface of the elastic adsorption member with a holder and deforming the adsorption surface downward into a convex spherical shape. In addition, the following can be achieved by the above-described die modification.

  For example, when the die is bonded to the substrate by thermocompression bonding, the central portion first deformed below the die contacts the substrate side, and then the contact portion with the substrate side sequentially expands to the die peripheral portion. Therefore, even if a void occurs between the center of the die and the substrate, the void follows the movement in which the contact portions of the die and the substrate move in sequence toward the end of the die and moves in a chasing manner. When the entire die is mounted on the substrate side, it is removed from the end of the die. Therefore, even a very thin die having a thickness of about 50 μm has almost no void residue and can always be mounted satisfactorily.

  Furthermore, even if a void is generated, it does not remain, so the hardness (rubber hardness) of the elastic adsorbing member can be set low, for example, a rubber hardness of about JIS-A60. The elastic adsorption member having such hardness has a function of correcting the inclination of the die by elastic deformation, and can perform better die adsorption and mounting on the substrate.

  In the present invention, the suction holes around the suction surface of the suction member can be formed at a plurality of locations around the suction surface in a substantially point-symmetrical arrangement with respect to the suction surface center. In this case, the shape of the suction surface of the elastic suction member can be various, such as a square, a circle, and an ellipse. Suction holes are formed in the periphery of this suction surface at a plurality of point-symmetrical points with the center of the suction surface as a point. As a result, the periphery of the suction surface sucks the die with a uniform suction force, and the central portion of the ultra-thin die is deformed into a convex spherical shape that is stable downward.

  In the present invention, the suction member before being supported by the holder is a flat rubber part in which the suction surface and the upper surface opposite to the suction surface are parallel. It can be formed to penetrate. When such a flat elastic adsorption member is pressed so that the side surface is held by the holder while a part of the holder is applied so that the upper surface of the elastic adsorption member is not deformed, the lower adsorption surface becomes a convex spherical shape downward. Deforms and the shape after deformation becomes stable.

  Specifically, according to the present invention, the suction surface of the elastic suction member is substantially rectangular, and suction of the same size and shape is provided at each of the four sides of the suction surface and / or at each of the four corners of the suction surface. Holes can be formed. In this case, the suction hole can be unified into a circular hole having a diameter of 0.5 mm to 1.5 mm.

  The elastic adsorbing member here is a substantially rectangular block body having four side surfaces and four corners. A suction hole is formed at one central position on each of the four sides of the substantially rectangular suction surface. The four suction holes in total are in a point-symmetric arrangement with respect to the center of the suction surface, and the die is sucked and deformed in a stable posture. In addition, a suction hole is formed at one central portion of each of the four corners of the substantially rectangular suction surface, and a total of four suction holes (in an array symmetrical with respect to the center portion of the suction surface) stabilize the die. Suction and deform in the posture. Furthermore, depending on the size and material of the die, suction holes can be formed at a total of eight locations, one on each of the four sides of the substantially rectangular suction surface and one on each of the four corners. The plurality of suction holes are preferably suction holes having the same size and shape, and specifically, circular holes having a diameter of 0.5 mm to 1.5 mm are preferable. That is, when the suction hole is a circular hole, the smaller the hole diameter is, the less voids are generated around the hole, but the suction force of the die is reduced and the hole machining becomes difficult. When the elastic adsorption member is rubber hardness rubber hardness JIS-A60, the hole diameter of the suction hole is a practical range of 0.5 mm to 1.5 mm in consideration of the suction adsorption force of the die and the workability of the hole itself, 0.8 mm is the best.

In the present invention, the holder for holding the elastic suction member, although a structure having a pawl portion that supports so as to embrace a plurality of duty post to one another apart from the side surface of the suction member, the claw portion of the holder It is preferable to configure a plurality of parts spaced apart at equal intervals. When the side surface of the elastic adsorbing member is partially pressurized with each of the plurality of claw portions, the portion that is pressurized and deformed by the claw portion on the side surface of the adsorbing member escapes to the portion that is not pressurized by the claw portion on the side surface of the adsorbing member The adsorption member can be attached to the holder in a more stable form.

  According to the present invention, when an ultra-thin die is sucked and sucked by the suction surface of the elastic suction member of the collet, the die remains flat or has a convex spherical shape so that the center portion of the die protrudes from the peripheral portion. Because it is deformed, it can be mounted so that the die is in contact with the substrate from the protruding central part. By doing this, even if a void occurs between the die and the substrate, the entire surface of the die is pressed against the substrate side. At this time, voids are eliminated and do not remain, and an excellent effect can be obtained that a good mount can be executed. Further, since voids do not remain when the die is mounted, occurrence of problems such as explosion of residual voids in a heat treatment process such as a resin molding process is eliminated, and the yield of semiconductor device manufacturing can be improved.

  Further, since the concern about residual voids is reduced, it is easy to apply a collet elastic adsorbing member having a low hardness, and an elastic adsorbing member having a rubber hardness of JIS-A60 can be used. Since the elastic adsorbing member having such hardness is excellent in adhesion to the die, the die can be mounted on the substrate while correcting the parallelism error, and the mounting performance can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  A collet 10 shown in FIGS. 1A and 1B includes an elastic adsorbing member 20 that is a rubber component of natural rubber or synthetic rubber, and a metal holder 30. As shown in FIGS. 4 (A) and 4 (B), the collet 10 sucks and sucks the ultra-thin die 4 and places a thermosetting resin film 41 on the substrate 40 as shown in FIGS. 5 (A) and 5 (B). And thermocompression bonding (mounting). The die 4 is a very thin semiconductor chip that is easily deformed when sucked by a rubber collet, for example, a square semiconductor chip having a thickness of 50 μm.

  The elastic adsorption member 20 is a substantially square flat rubber component having a thickness of about 4 mm. The lower surface of the suction member 20 is a substantially square suction surface 20a, and is flattened. The vertical and horizontal sizes of the suction surface 20 a are set slightly smaller than the vertical and horizontal sizes of the die 4. As shown in FIG. 3A, when the suction surface 20 a is roughly divided into a central part M and a peripheral part N, a vacuum suction hole 21 is formed only in the peripheral part N. The suction hole 21 is a through-hole that reaches the upper surface from the lower surface, which is the suction surface 20 a, and is formed at one location near the center of each of the four side surfaces 20 b of the suction member 20. Each suction hole 21 is in a point-symmetric position with respect to the center point of the suction surface 20a. All the suction holes 21 in four places are circular holes having the same hole diameter. The hole diameter corresponds to the rubber hardness of the adsorption member 20, and the hole diameter in the case of rubber hardness JIS-A60 is 0.8 mm, for example.

  The holder 30 has four claw portions 30c that hold the four side surfaces 20b of the elastic adsorption member 20 so as to be pressed and held. The holder 30 includes a hollow shaft portion 30a and a flange portion 30b integrated with a lower end portion of the hollow shaft portion 30a, and has a claw portion 30c integrally on the lower surface of the flange portion 30b. As shown in FIG. 3B, a suction groove 32 is formed in a cross shape on the lower surface of the flange portion 30b, and the center of the suction groove 32 communicates with the lower end of the vacuum suction hole 31 penetrating the hollow shaft portion 30a. The four claw portions 30c are separated from each other so as to hold the central portion of each of the four side surfaces 20b of the adsorption member 20. The length from the lower surface of the flange portion 30 b to the tip of the claw portion 30 c is set to be smaller than the thickness D of the adsorption member 20. The distance between the two opposed claw portions 30c is set slightly smaller than the distance between the two opposed side surfaces of the four side surfaces 20b of the adsorption member 20.

  As shown in FIG. 2, when the inner surface of the four claw portions 30 c of the holder 30 is fitted to the four side surfaces 20 b of the adsorption member 20, each of the four side surfaces 20 b is pressed by the corresponding claw portion 30 c and the opposite two side surfaces approach each other. It deforms in the compression direction. The adsorbing member 20 is fitted to a position where the upper surface abuts against the lower surface of the flange portion 30b and is held by the four claw portions 30c. The upper end opening of the four suction holes 21 of the suction member 20 communicates with the tip of the cross-shaped suction groove 32 on the lower surface of the corresponding flange portion 30b. When the corresponding four claw portions 30c pressurize the central portion of the four side surfaces 20b of the adsorption member 20, the adsorption member 20 is elastically deformed downward in a substantially arcuate shape, and the central portion M of the adsorption surface 20a is a convex spherical shape downward. Protrude slightly.

  Next, the die suction adsorption operation shown in FIGS. 4A and 4B by the collet 10 and the mounting operation shown in FIGS. 5A and 5B will be described.

  FIG. 4A shows a state in which the collet 10 is lowered toward the die 4 and the suction member 20 is pressed against the die 4 to be sucked. By pressing the suction surface 20 a of the suction member 20 against the upper surface of the die 4, the suction surface 20 a comes into close contact with the upper surface of the die 4. The die 4 is stuck on, for example, an adhesive sheet 6. As shown in FIG. 4B, when the vacuum suction hole 31 of the holder 30 is evacuated, the suction hole 21 becomes negative pressure through the suction groove 32, and the die 4 is vacuum-sucked. By sucking the ultra-thin die 4 through the suction holes 21 provided only in the peripheral portion N of the suction surface 20a, the suction surface peripheral portion N and the peripheral portion of the die 4 are compressed in the plate thickness direction by the die suction force. Deform. At this time, the central portion M of the suction surface 20a is not deformed positively because the die suction force does not act so much, and is deformed according to the deformation of the peripheral portion N. FIG. 4B shows a state in which the die 4 is picked up from the adhesive sheet 6 by the collet 10, and the die 4 adsorbed by the adsorbing member 20 is deformed so that the central portion protrudes downward into a convex spherical shape, It is kept as it is.

  An example of the shape of the die 4 at this time is shown in FIG. In the die 4 of FIG. 6A, the central part of the four sides is deformed upward by the suction force of the four suction holes 21, and the four corners are slightly deformed according to the deformation of the central part of the four sides. The central portion 4a surrounded by the four side portions and the four corner portions remains most undeformed. The central portion 4a protrudes in a substantially convex spherical shape below the four side portions and the four corner portions.

  Next, as shown in FIG. 5A, the die 4 is pressed against the thermosetting resin film 41 on the substrate 40 by the collet 10 and thermocompression bonded. At this time, as shown in FIG. 6B, the die 4 is first pressed downward by the elastic adsorption member 20 with the central portion 4 a protruding downward contacting the resin film 41. The elastic adsorbing member 20 is compressed in the plate thickness direction by the reaction force of the elastic adsorbing member 20 pressing the die 4 against the resin film 41, and the adsorbing surface 20a and the die 4 become flat as shown in FIG. The entire surface of 4 is bonded to the resin film 41. In the die 4, the central portion 4 a that first contacts the resin film 41 is in contact with the resin film 41, and the contact portion expands sequentially to the periphery of the die and finally becomes flat. Since the central portion 4a that protrudes downward from the die 4 first contacts the resin film 41, it is difficult for voids to occur between them. Moreover, even if a void occurs between the central portion 4a and the resin film 41 that contacted first, the portion that contacts the resin film 41 spreads from the central portion 4a to the peripheral portion of the die 4 so that the void is expelled. In response, most of the voids are removed from the end of the die 4 when the entire surface of the die 4 contacts the resin film 41. Therefore, at the time of mounting in FIG. 5 (B), there is almost no residual void, and good mounting is performed.

  The collet 10 described above is provided with a circular suction hole 21 at each of the four side centers of the suction surface 20a of the suction member 20 which is a substantially square flat rubber component having a thickness of about 4 mm. As the hole diameter of the suction hole 21 is smaller, the generation of voids may be reduced. However, from the viewpoint of workability, 0.5 mm or more is desirable. Further, as the hole diameter increases, voids are generated, and the die itself is likely to be partially deformed. When the elastic adsorbing member 20 has a rubber hardness of JIS-A60, a hole diameter of 0.8 mm is most desirable in terms of die adsorbing power and workability.

  Further, when the adsorption member 20 is used as described above, the void generation itself at the time of die mounting is reduced and the residual voids are also reduced, so that the rubber hardness of the adsorption member 20 can be lowered. For example, it is easy to set the rubber hardness to JIS-A60. With this rubber hardness, the adhesion to the die 4 is good, and the mountability of the die 4 can be further improved. If the rubber hardness is further reduced, the suction member may be deformed excessively, so that the rubber hardness of the elastic suction member 20 is preferably JIS-A60.

  Next, another embodiment will be described with reference to FIGS.

  In FIG. 7, circular suction holes 21 are formed at one of the four corners of the substantially square suction surface 20 a of the elastic suction member 20. Here, the four corners are located in the peripheral portion N of the suction surface 20a, and each suction hole 21 is point-symmetric with respect to the center point of the suction surface 20a. The diameter of each suction hole 21 may be the same as in FIG. The form of die suction suction by the elastic suction member 20 of FIG. 7 is the same as that of FIG. 1, and detailed description thereof is omitted. The same applies to the embodiment shown in FIGS.

  In FIG. 8, circular suction holes 21 are formed at a total of eight places, one on each of the four sides of the substantially square suction surface 20 a of the elastic suction member 20 and one on each of the four corners. Each suction hole 21 in this case is also in a point-symmetric position with respect to the center point of the suction surface 20a. Further, the diameter of each suction hole 21 is preferably smaller than that in the case of FIG. 1 in accordance with the increase in the number of holes.

  In FIG. 9, an arcuate suction hole 21 ′ is formed at one central portion of each of the four sides of the substantially square suction surface 20 a of the elastic suction member 20. A total of four suction holes 21 'are point-symmetric with respect to the center point of the suction surface 20a.

  The collet for die bonder of the present invention is not limited to the above-described embodiment, and it is needless to say that various changes can be made without departing from the gist of the present invention.

(A) is a side view including the partial cross section of the collet for die bonders which shows embodiment of this invention, (B) is a bottom view. It is a decomposition | disassembly side view of the collet of FIG. (A) is a bottom view of the elastic adsorption member in the collet of FIG. 2, and (B) is a bottom view of the holder. (A) is a side view of the collet of FIG. 1 when the die is attracted, and (B) is a side view of the die pick-up. (A) is the side view in the middle of the die mount of FIG. 1 collet, (B) is the side view at the time of mounting. (A) is the elements on larger scale before mounting operation of FIG. 5 (A), (B) is the elements on larger scale at the time of mounting operation. It is a top view of the elastic adsorption member which shows other embodiment. It is a top view of the elastic adsorption member which shows other embodiment. It is a top view of the elastic adsorption member which shows other embodiment. It is sectional drawing of the conventional rubber collet of a type with an edge. It is sectional drawing of the conventional surface type rubber collet. FIG. 11 is a cross-sectional view when the die is sucked and sucked by the collet.

Explanation of symbols

4 die 10 collet 20 elastic adsorption member 20a adsorption surface 20b side surface 21 suction hole 30 holder 30c claw part 32 suction groove 40 substrate 41 thermosetting resin film

Claims (5)

Comprising an elastic suction member formed with vacuum suction holes in the periphery except for the central portion of the flat suction surface for sucking adsorb die, the elastic suction member and a holder for holding under pressure from the side of the elastic suction member The holder has a claw portion for supporting the side surface of the elastic adsorbing member so as to embrace a plurality of spaced apart portions .   2. The collet for a die bonder according to claim 1, wherein the suction holes are formed at a plurality of locations around the suction surface in a substantially point-symmetrical arrangement with respect to the central portion of the suction surface. The elastic suction member is a flat rubber part having a uniform thickness from the suction surface to a surface opposite to the suction surface, and the suction hole is penetrated in the thickness direction from the suction surface. Item 3. The collet for die bonder according to item 1 or 2.   The suction surface is substantially rectangular, and the suction holes having the same size and shape are formed at each of the four sides of the suction surface and / or at one of the four corners of the suction surface. The collet for die bonders according to any one of claims 1 to 3.   The collet for die bonder according to claim 4, wherein the suction hole is a circular hole having a diameter of 0.5 mm to 1.5 mm.

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