JPH08288288A - Bump holding device for transfer - Google Patents

Abstract

PURPOSE: To reduce the cost for transferring bump balls by a suction holding type transfer bump method for producing small-quantity of diversified LSI chips. CONSTITUTION: Many recessed portions 6 for holding bump balls are arranged in parallel in a main body 2 of a holding plate. A mask plate 3 is superimposed on the main body 2 of the holding plate. Bump ball positioning holes 9 are made in the mask plate 3 at the positions corresponding to the bump transfer positions for LSI chips. These main bodies 2 of the holding plate and a mask plate 3 are brought into contact tightly with a supporting frame 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer bump holding device used for transferring a bump ball for mounting a semiconductor integrated circuit element on a structure such as a module substrate to an electrode of the semiconductor integrated circuit element. .

[0002]

2. Description of the Related Art In recent years, development has been underway to reduce the cost and size of a system by converting a semiconductor integrated circuit device (hereinafter simply referred to as an LSI chip) into a multi-chip module. For this reason, much research and development has been conducted on the technology for mounting an LSI chip on a module substrate.

In the past, the method of connecting the electrodes formed on the peripheral portion of the upper surface of the LSI chip and the wiring pattern of the module substrate via wires has been the mainstream. However, this method has a problem that it is not possible to increase the number of electrodes and increase the number of pins because the number of wires is limited because interference between wires must be avoided.

As a mounting method capable of solving this problem,
An area bump method has been proposed in which electrodes can be arranged at random positions on an LSI chip. In this area bump method, ball-shaped bumps are provided on the electrodes of the LSI chip, and the LSI chips are surface-mounted on the module substrate by connecting the bumps to the wiring pattern of the module substrate. The area bump method has advantages in that the number of electrodes can be increased and the electric resistance can be reduced as compared with the method of pulling out the wire from the LSI chip.

As a method of forming the bump on the electrode of the LSI chip, a stud bump method, a lift-off method,
There is a transfer bump method. What is the stud bump method?
This is a method in which a wire is connected to a predetermined pad position of a pad pattern on an LSI chip and then cut to form a ball shape. Since this method is not batch processing because bumps are formed at predetermined pad positions, throughput decreases as the number of electrodes increases. In addition, there is a drawback that a large load is applied to the LSI chip due to the connection of the wires.

The lift-off method is a method of forming bumps at desired pad positions by vapor deposition or electrolytic plating using a resist mask or mask plate. This method is unreliable because the process is complicated due to the steps such as resist coating, exposure, development, solder vapor deposition or plating, and reflow, and the yield of formed bumps is unstable. There is a drawback that.

In the transfer bump method, the bumps are previously LS
It is held on a holding plate different from the I-chip, and this holding plate is
This is a method of transferring from the holding plate to the LSI chip so as to be superposed on the I chip. There are the following two methods for holding the bumps on the holding plate. (1) The bump is formed by subjecting the holding plate to some processing such as a lift-off method. At this time, bump the LSI
It is formed at a position corresponding to each pad of the chip.
Then, the holding plate is placed on the LSI chip so that the bumps come into contact with the pads of the LSI chip, and then the bumps are transferred to the LSI chip by heating by reflow or the like. (2) A bump ball holding recess is formed at a position corresponding to the LSI chip pad on the surface of the holding plate, and the air suction port of the air suction device is connected to this recess. Then, the bump ball previously formed into a ball shape is held by suction in the bump ball holding concave portion. After that, the bump balls are transferred to the LSI chip in the same manner as the method (1).

That is, by adopting such a transfer bump method, a large number of bumps can be provided on the LSI chip at one time. Moreover, an excessive load is not applied to the LSI chip, and by adopting the method (2), the problems such as the increase in the number of processes and the decrease in the yield caused by using the resist mask by the lift-off method can be solved. can do.

[0009]

However, even when the method (2) of holding the bump ball on the holding plate by suction is adopted, there are the following problems. That is, the holding plate must be formed of a material, such as quartz, that can withstand the heat applied at the time of transfer and that does not bond the bump balls even if heated, which increases the material cost. In addition, this holding plate must be specially processed in order to form a large number of bump ball holding recesses having a structure communicating with the air suction device. For this reason, the manufacturing cost of the holding plate increases, and the time required for manufacturing increases.

In addition to this, since it is necessary to form a bump ball holding recess in the holding plate so as to correspond to the pad position of the LSI chip, it should be used for LSI chips of different types having different pad positions. I can't. Therefore, it is necessary to prepare a holding plate for each type of LSI chip, which further increases the cost. In particular, in the gate array type LSI chip which has been widely used in recent years, the connection pattern corresponding to the desired product type is selected from the array of the standard pad patterns, and the holding plate must be formed for each product type. However, there has been a strong demand for cost reduction.

The present invention has been made in order to solve the above-mentioned problems, and is intended for small-quantity and large-variety LSI chips.
An object of the present invention is to make it possible to suppress an increase in cost when transferring a bump ball by a transfer bump method of holding the bump ball on a holding plate by suction.

[0012]

According to a first aspect of the present invention, there is provided a transfer bump holding device including a holding plate body having a plurality of bump ball holding concave portions arranged in parallel, and a bump at a portion corresponding to a bump transfer position of a semiconductor element. The holding plate is composed of a mask plate having ball positioning holes opened therein and a support frame for closely contacting and supporting the holding plate body and the mask plate.

A transfer bump holder according to a second aspect of the present invention is the transfer bump holder according to the first aspect of the present invention.
The bump ball holding concave portion formed in the holding plate body is formed at a position corresponding to all external connection electrodes of the semiconductor element.

A transfer bump holding device according to a third aspect of the present invention is the transfer bump holding device according to the first or second aspect of the present invention, wherein the support frame has a structure in which at least a mask plate can be inserted and removed. is there.

[0015]

According to the first aspect of the invention, among the many recesses for holding the bump balls of the holding plate body, the recesses corresponding to the bump transfer positions of the semiconductor element are opened through the bump ball positioning holes of the mask plate, and the bump transfer is performed. Since the concave portion that does not correspond to the position is closed by the mask plate, the bump ball holding position is determined by the position of the bump ball positioning hole in the mask plate. Therefore, only the mask plate needs to be formed for each type of semiconductor element. Since the mask plate does not hold the bump balls, the mask plate can be formed of an inexpensive material having lower heat resistance, non-bonding property of the bump balls, and lower rigidity than quartz or the like.

According to the second invention, when the bump transfer positions of the semiconductor element are continuous over a plurality of locations,
The bump ball positioning holes in the mask plate may be opened so that the plurality of bump ball holding recesses are exposed.

According to the third aspect of the invention, even if the support frame is fixed to the transfer mechanism of the automatic transfer device or the like, when the type of semiconductor element changes, the holding plate body is not removed from the support frame and only the mask plate is used. Can be replaced.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to FIGS. FIG. 1 is a perspective view of a transfer bump holding device according to the present invention, and FIG. 2 is a sectional view of the same. FIG. 2 is shown in a state of being broken along a direction orthogonal to a mask plate attaching / detaching direction. FIG. 3 is a plan view of the holding plate body and the LSI chip. FIG. 3A shows the holding plate body, and FIG.
Indicates an LSI chip. It should be noted that the holding plate body shown in FIG. 7A shows only the portion corresponding to the LSI chip. FIG. 4 is a plan view in which the mask plate is placed on the holding plate body.

In these figures, reference numeral 1 is a transfer bump holder according to this embodiment. This transfer bump holding device 1 includes a holding plate body 2 formed in a rectangular plate shape in plan view.
And a mask plate 3 superposed on the holding plate body 2,
The holding plate body 2 and the mask plate 3 are composed of a support frame 4 that supports them so that they are in close contact with each other. The support frame 4 is made of metal and has a structure that surrounds the holding plate body 2 and the mask plate 3 on three sides, and a supporting plate 4a for supporting the lower surface of the holding plate body 2 is provided at the lower part of the supporting plate 4a. A guide groove 4b is formed in which a side portion of the mask plate 3 is slidably fitted. That is, the mask plate 3 can be freely inserted into and removed from the support frame 4.

Further, as shown in FIG. 2, a cover 5 is fixed to the lower portion of the support frame 4 so as to be in close contact with the lower surface of the support plate 4a. The cover 5 has a structure that forms an air chamber A between the cover 5 and the lower surface of the holding plate body 2, and has an air outlet portion 5a communicating with the air chamber A in the lower portion. By connecting an air suction device (not shown) to the air outlet portion 5a, the air in the air chamber A is discharged through the air outlet portion 5a as shown by the arrow in the figure.

In the present embodiment, the holding plate body 2 is made of quartz, and a bump ball holding recess 6 having a circular shape in plan view is formed on the upper surface of the holding plate body 2 which faces the mask plate 3 as shown in FIGS. 2 and 3A. Many are formed. This recess 6 is shown in FIG.
2 is formed at each position corresponding to the pad 7a as the external connection electrode of the LSI chip 7 shown in FIG. 2 and, as shown in FIG. It has a structure that communicates with the room A. The recess 6 is formed by machining the quartz holding plate body 2 to have an opening diameter of about 100 μm and a rectangular cross section. The thickness of the holding plate body 2 is about 2 mm.

The LSI chip 7 is of a gate array type, and has a structure in which the product type is determined according to the connection pattern of a large number of pads 7a formed. That is, even one LSI chip 7 has different pads 7
By connecting a to a module substrate (not shown), the product types will be different. In addition, this LSI chip 7
Has a longitudinal dimension L of 15 mm or less.

The mask plate 3 is made of plastic in this embodiment, and the pads 7a of the large number of pads 7a of the LSI chip 7 are connected to the module substrate.
As shown in FIG. 1, the bump ball positioning hole 9 is provided at a portion corresponding to a, that is, a portion corresponding to the bump transfer position.
Is opened. As the plastic for the mask plate 3, an inexpensive plastic such as a thermoplastic that can withstand a temperature of 100 ° C to 200 ° C was used. The bump ball positioning hole 9 is
In this embodiment, the opening shape is a square in plan view. The opening of the bump ball positioning hole 9 in the mask plate 3 was performed by laser processing in this embodiment. Furthermore, the opening shape of the bump ball positioning hole 9 is not limited to the square shape of this embodiment, but may be changed to a circular shape.

In FIG. 2, the reference numeral 10 located in the bump ball positioning hole 9 is a bump ball, and this bump ball 10 is the same as that used in the conventional transfer bump method.

Next, a method of transferring the bump ball 10 to the pad 7a of the LSI chip 7 using the transfer bump holding device 1 having the above-described structure will be described. First, as shown in FIG. 1, the holding plate body 2 and the mask plate 3 in which the bump ball positioning holes 9 are previously opened are mounted on the support frame 4. At this time, the holding plate body 2 is supported by the support plate 4a of the support frame 4, the mask plate 3 is fitted into the guide groove 4b of the support frame 4, and the lower surface of the mask plate 3 is closely contacted with the upper surface of the holding plate body 2. Let In addition, the holding plate body 2 has a recess 6
The mask plate 3 is mounted so that the opening side thereof is the mask plate 3 side.

When the mask plate 3 is superposed on the upper surface of the holding plate body 2 as described above, the bump ball positioning holes 9 of the mask plate 3 among the large number of concave portions 6 of the holding plate body 2 as shown in FIG.
The concave portion 6 at the position corresponding to the above is opened upward through the mask plate 3, and the concave portion 6 at the position where the bump ball positioning hole 9 is not opened is closed by the mask plate 3.

That is, as shown in FIG. 4, when the mask plate 3 is superposed on the upper surface of the holding plate main body 2 as seen from above,
The concave portion 6 is exposed below the bump ball positioning hole 9.
The mask plate 3 shown in FIG. 4 is different from the mask plate 3 shown in FIG. 1 in the type of compatible LSI chip, and the opening position and the number of the bump ball positioning holes 9 are different.

After that, the air suction device is started. When the air suction device is started, the air above the mask plate 3 moves the bump ball positioning hole 9 → inside the recess 6 → air hole 8 → air chamber A.
→ It is sucked into the air suction device by the air suction system called the connection portion 5a. In this state, the bump ball 1 is placed on the mask plate 3.
When 0s are scattered, bump balls 10 are formed as shown in FIG.
Are adsorbed to the concave portions 6 corresponding to the bump ball positioning holes 9. At this time, the upper half portion of the bump ball 10 projects above the mask plate 3. In other words, the depth dimension of the recess 6 and the thickness of the mask plate 3 are set such that the upper half of the bump ball 10 projects onto the mask plate 3 when the bump ball 10 is attracted as described above. are doing.

After the bump balls 10 are thus sucked, the support frame 4 is tilted, so that the remaining bump balls 1 not scattered on the mask plate 3 are scattered.
Eliminate 0. As a result, only the necessary bump balls 10 are held by the holding device 1. Thereafter, the holding device 1 is mounted on the LSI chip 7 so that the upper surface of the mask plate 3 faces the pad forming surface of the LSI chip 7 which is held and fixed in advance on a holding table (not shown) or the like.
The pad 7a is contacted. In this stacking step, the target LSI chip position of the transfer bump holding device 1 (shown by a chain double-dashed line in FIGS. 1 and 4) is accurately positioned with respect to the LSI chip 7. In this stacking step, the transfer bump holding device 1 can be mounted on the transfer mechanism part of the automatic transfer device and automatically performed.

Then, the LSI is manufactured by the same method as the conventional one.
The bump ball 10 is heated by placing the chip 7 on, for example, a hot plate type heating device,
It is bonded to the pad 7a of the chip 7. After bonding, the air suction device is stopped and the transfer bump holding device 1 is separated from the LSI chip 7. This completes the entire process of transferring the bump balls 10.

When the type of the LSI chip 7 is changed, the mask plate 3 is slid out from the support frame 4 along the guide groove 4b, and another mask plate 3 suitable for the type of the LSI chip 7 is used. Attach to. As a result, the bump balls 10 can be transferred to different types of LSI chips by using one type of holding plate body 2. At this time, even if the support frame 4 is fixed to the transfer mechanism of the automatic transfer device or the like, since the support frame 4 has a structure in which the mask plate 3 can be freely taken in and out, the holding plate main body 2 is supported by the support frame 4. Only the mask plate 3 can be replaced without removing it.

Therefore, according to the transfer bump holding apparatus 1 shown in this embodiment, among the many recesses 6 of the holding plate body 2, the recesses 6 corresponding to the bump transfer positions of the LSI chip 7 are formed.
Are opened through the bump ball positioning holes 9 in the mask plate 3, and the recesses 6 that do not correspond to the bump transfer positions are in the mask plate 3
The bump ball holding position is determined by the position of the bump ball positioning hole 9 in the mask plate 3. Therefore, when the bump balls 10 are collectively held and transferred, only the mask plate 3 needs to be formed for each type of the LSI chip 7.

In the above embodiment, the bump ball positioning hole 9 is opened at each bump transfer position of the LSI chip 7 (each recess 6 of the holding plate body 2), but the bump transfer position of the LSI chip 7 is shown. In the case where is continuous over a plurality of positions, the bump ball positioning hole 9 can be formed as shown in FIG. FIG. 5 is a view showing another embodiment of the mask plate in which the shape of the bump ball positioning holes is changed, and this drawing is drawn with the mask plate overlaid on the holding plate body as in the case of FIG. The bump ball positioning hole 9 of the mask plate 3 shown in the figure is made larger than that of the above embodiment so that the plurality of recesses 6 are exposed.

As described above, the bump ball can be held at a desired position even if the bump ball positioning hole 9 is largely opened because the recess 6 of the holding plate body 2 is located at a position corresponding to each pad 7a of the LSI chip 7. Because it is formed.

Further, in the above-mentioned embodiment, an example in which the concave portion 6 of the holding plate main body 2 is formed by machining is shown, but the concave portion 6 may be formed by using the lithography technique by applying the patterning method of LSI. it can. That is, in this case, the resist mask is formed on the base material of the holding plate body 2, and the recess 6 is formed by etching the base material with hydrofluoric acid.

Since the fine processing can be performed by using the lithography technique as described above, the opening diameter of the concave portion 6 is about 10 μm.
It can be narrowed to a certain degree. As a result, bump balls having a smaller diameter than the bump balls used in the above-described embodiment can be used, so that the number of pads formed on the LSI chip can be further increased and the mounting density can be further increased.

Further, in the above-described embodiment, the holding plate body 2
Although the recesses 6 of the above are formed so as to correspond to the individual pads 7a, the present invention is not limited to such a limitation, and the recesses 6 can be formed in a larger number than the pads 7a, and the forming range is the outer shape of the LSI chip 7. It can be expanded from the range corresponding to. By doing so, it becomes possible to transfer the bump balls to an LSI chip of a type different from the gate array type LSI chip. Moreover, the cross-sectional shape of the recess 6 is not limited to the rectangular shape shown in the above embodiment,
If the bump ball 10 can be held and suctioned from the lower surface side of the holding plate body 2, such as a conical shape that tapers downward, the same effect can be obtained regardless of the shape. To be

[0038]

As described above, in the transfer bump holding device according to the first aspect of the present invention, the holding plate main body in which a large number of bump ball holding concave portions are arranged side by side is provided in the portion corresponding to the bump transfer position of the semiconductor element. Since the holding plate is composed of the mask plate with the bump ball positioning holes opened and the supporting frame for closely supporting the holding plate body and the mask plate, among the many bump ball holding concave portions of the holding plate body. Since the concave portion corresponding to the bump transfer position of the semiconductor element is opened through the bump ball positioning hole of the mask plate, and the concave portion not corresponding to the bump transfer position is closed by the mask plate, depending on the position of the bump ball positioning hole of the mask plate. The bump ball holding position will be determined.

For this reason, only the mask plate need be formed for each type of semiconductor element. Since the mask plate does not hold the bump balls, it can be formed of an inexpensive material that has lower heat resistance, non-bonding property of the bump balls, and lower rigidity than quartz or the like. Therefore, when transferring bumps to a large number of semiconductor elements of a small amount, a holding plate body that is made of a material having a high heat resistance and a high non-bonding property of the bump balls is formed, and a plurality of concave portions for holding the bump balls are formed.
Since only the types need be formed, the cost can be reduced. In addition, since the mask plate formed for each product type has high workability, it can be manufactured in a short time, so that the bump balls can be transferred with high throughput even if the number of product types of semiconductor elements increases.

A transfer bump holder according to a second aspect of the present invention is the transfer bump holder according to the first aspect of the present invention.
Since the bump ball holding recesses formed in the holding plate body are formed at positions corresponding to all the external connection electrodes of the semiconductor element, when the bump transfer positions of the semiconductor element are continuous over a plurality of positions, The ball positioning hole may be opened so that the plurality of bump ball holding recesses are exposed. Therefore, in this case, since the number of bump ball positioning holes formed in the mask plate is reduced, the mask plate can be easily processed.

A transfer bump holding device according to a third aspect of the present invention is the transfer bump holding device according to the first aspect or the second aspect of the invention, in which the support frame has a structure in which at least the mask plate can be inserted and removed. Even if the frame is fixed to the transfer mechanism of the automatic transfer device or the like, it is possible to replace only the mask plate without removing the holding plate body from the support frame when the type of semiconductor element changes. Therefore, it is easy to perform the setup change work accompanying the change of the type of the semiconductor element.

[Brief description of drawings]

FIG. 1 is a perspective view of a transfer bump holding device according to the present invention.

FIG. 2 is a cross-sectional view of a transfer bump holding device according to the present invention, which is shown in a state of being broken along a direction orthogonal to a mask plate attaching / detaching direction.

FIG. 3 is a plan view of a holding plate body and an LSI chip,
The figure (a) shows the holding plate body, and the figure (b) shows the LSI chip.

FIG. 4 is a plan view showing a state where the mask plate is superposed on the holding plate body.

FIG. 5 is a view showing another embodiment of the mask plate in which the shape of the bump ball positioning hole is changed.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Transfer bump holding device, 2 ... Holding plate main body, 3 ... Mask plate, 4 ... Support frame, 6 ... Recessed part, 7 ... LSI chip, 8 ...
Air holes, 9 ... Bump ball positioning holes, 10 ... Bump balls.

Claims (3)

[Claims] 1. A transfer method for holding a bump ball in a large number of recesses for holding a bump ball on the surface of a holding plate by suction and stacking the holding plate on a semiconductor element so that the bump balls are collectively transferred to the semiconductor element. In the bump holding device, the holding plate includes a holding plate body having a large number of recessed portions for holding bump balls arranged in parallel, and a bump ball positioning hole is formed at a portion corresponding to a bump transfer position of a semiconductor element. A transfer bump holding device, comprising: a mask plate to be stacked on the ball holding recess side; and a support frame for closely holding and supporting the holding plate body and the mask plate. 2. The transfer bump holding device according to claim 1, wherein the bump ball holding recess formed in the holding plate body is formed at a position corresponding to all external connection electrodes of the semiconductor element. Transfer bump holding device. 3. The transfer bump holder according to claim 1, wherein the support frame has a structure in which at least the mask plate can be inserted and removed.