JP2812304B2 - Repair method for flip-chip type semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for repairing a flip-chip type semiconductor device, and more particularly to a repair method suitable for a flip-chip type semiconductor device employing gold bumps.

[0002]

2. Description of the Related Art Conventionally, a flip chip type semiconductor is generally mounted on a substrate by the following method. That is, the LSI chip is mounted face down on the substrate, the solder bumps formed on the pads of the substrate are melted in an N ₂ atmosphere, and the substrate and the LSI chip are electrically connected. Also,
When removing a defective LSI chip from the substrate,
The SI chip is heated to melt the solder, and the LSI chip is peeled off.

Various techniques of such a repair method have been disclosed. For example, when a connection bump between an LSI chip and a wiring board is a solder bump, a repair method is described in "MES '95 6th Microelectronics Symposium", pages 151-154, published by SHM, and JP-A-3-253049. It is disclosed in a gazette (flip chip bonding repair method).

[0004]

SUMMARY OF THE INVENTION However, LSI
If the connection bump between the chip and the wiring board is gold, use LSI
The repair method has not been established because it is difficult to supply the solder again to the substrate after chip removal. That is, L
After the removal of the SI chip, the molten and wet state of the solder differs at each bump joint, so that the solder is removed at the spots, but the solder remains unevenly on the mounting pads of the wiring board, and the solder must be resupplied. It was difficult.

[0005] Here, in the initial mounting of an LSI chip in which gold is used for the connection bump, generally, solder is applied in advance to the LSI mounting pad of the wiring board, and this solder is connected to the gold bump of the LSI chip. Do it. As a method of supplying the solder to the board side, there are a Super Jafit method of Showa Denko KK and a super solder method of Furukawa Denko KK. LS
It is not suitable for re-solder supply when replacing an I chip.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a repair method suitable for a flip-chip type semiconductor device using gold bumps, which alleviates the disadvantages of the prior art.

[0007]

In order to achieve the above object, in the present application, a solder bonding a flip-chip type semiconductor to a chip mounting pad provided on a wiring substrate is melted, and the flip-chip type is removed from the wiring substrate. A removing step of removing the semiconductor, a solder supplying step of applying solder to the chip mounting pad, and a reattaching step of melting the solder applied to the chip mounting pad and joining a substitute semiconductor to the chip mounting pad. In the method of repairing a flip-chip type semiconductor device having the following, the following method is employed.

According to the first aspect of the present invention, the solder supply
The process is to apply flux to the chip mounting pad
The first step, the solder pieces punched from the solder film
Adhere to the chip mounting pad via the flux
And the second step of causing
You.

In the present invention, a fine solder piece punched out of a solder film is supplied to a chip mounting pad by adhering to a flux previously applied to the chip mounting pad.

[0010] In the second aspect of the present invention, the solder supply step includes a first step of applying a flux to a heat conductive substrate provided separately from the wiring substrate, and a step of applying a solder piece punched from a solder film to the wiring. A second step of attaching the chip to the thermally conductive substrate via the flux in accordance with the arrangement of the chip mounting pads provided on the substrate, and the solder pieces attached to the thermally conductive substrate contacting the chip mounting pad Thus, a third step of causing the heat conductive substrate to face the wiring substrate and applying heat to the heat conductive substrate to melt the solder pieces is provided.
In the present invention, a plurality of solder pieces attached to the heat conductive substrate in accordance with the arrangement of the chip mounting pads are opposed to the wiring board in accordance with the position of the heat conductive substrate in which the chip mounting pads are arranged. The piece is supplied to the chip mounting pads by being melted in a state of being substantially in contact with each chip mounting pad.

In the second aspect of the present invention, when melting the solder piece, nitrogen gas may be blown toward the melting point. According to this, the surface of the solder supplied to the chip mounting pad by melting is smoothed.

According to the second aspect of the present invention, when the heat conductive substrate is opposed to the wiring substrate, the chip mounting pad and the solder piece are almost in contact between the chip mounting pads. You may make it arrange | position a metal plate which has about a thickness. According to this, due to the thickness of the metal plate sandwiched between the heat conductive substrate and the wiring board,
The distance between the heat conductive substrate and the wiring substrate is maintained so as not to approach a certain distance or more.

Accordingly, the above-mentioned object is achieved.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION

[First Embodiment] An embodiment of the present invention will be described below with reference to FIG.

After the LSI chip is mounted on the wiring board 5, the LSI chip is completely adhered with a sealing resin 6 as shown in FIG. 1 (b).
Is usually determined. Now, it is assumed that as a result of this determination, the LSI chip 2 in FIG. 1A is defective.

First, a method of removing the defective LSI chip 2 will be described.

As shown in FIG. 1A, an LSI adsorption heating means 1
Is adsorbed to the defective LSI chip 2, the defective LSI chip 2 is heated to melt the solder, and the defective LSI 2 is peeled off from the wiring board 5. The LSI adsorption and heating means 1 has a heating and pressing mechanism and a suction mechanism for an LSI chip. At this time, the defective LSI chip 2 is peeled off from the wiring substrate while blowing nitrogen gas onto the joint portion 4 between the defective LSI 2 and the wiring substrate 5. The removal of the defective LSI chip 2 is performed by operating the LSI adsorption and heating means 1 which holds the defective LSI chip 2 by suction.

According to this, after the LSI chip 2 is removed, the variation in the solder remaining on the LSI mounting pad 11 is suppressed, and the step of smoothing the surface of the LSI mounting pad 11 for reattaching the chip is omitted. Can be
The repair process can be simplified.

Here, as a more specific example of the present embodiment, an epoxy sealing resin is used as the sealing resin 6. Heating of the defective LSI chip 2 by the LSI adsorption and heating means 1 was performed at 250 to 300 ° C. Nitrogen gas was blown under the condition that the oxygen concentration was 500 ppm or less.

Next, a method of mounting the alternative LSI chip will be described.

FIG. 1B shows a state after the defective LSI chip 2 is removed. On the wiring board 5, a set of LSI
The mounting pad 11 is left. In this state,
First, a flux 13 is applied to the LSI mounting pad 11 in a layered manner. Subsequently, the layered solder film 8 spread on the surface of the die 7 is mounted together with the die 7 on the mounting pad 1.
1 and punched out the solder film 8 using a punch 9. In this way, the punched layered solder disk 10 is applied to the upper layer of the LSI mounting pad 11 (hereinafter, this solder supply method is referred to as a micro press method. The micro press method is a method for forming a metal projection and a jig (special method). No. 02-178854).) The solder disk 10
Flux 13 previously applied to LSI mounting pad 11
To the LSI mounting pad 11 (FIG. 1).
(D)).

Subsequently, as shown in FIG.
The SI chip 12 is adsorbed by the LSI adsorption heating means 1 and
Positioning is performed above the SI mounting pad 11. Then, the LSI adsorption and heating means 1 is heated to a predetermined temperature to raise the temperature of the new LSI chip 12, and then the wiring board 5 is pressed to melt the solder disk 10. Thus, the new LSI chip 12 and the LSI mounting pad 11 are joined. After that, as shown in FIG.

According to this, even when there is a component already mounted around the chip re-attachment position, the solder disk 10 can be supplied to a desired position corresponding to the LSI mounting pad 11, thereby facilitating repair work. Can be achieved.

Here, if a more specific example of the present embodiment is shown, it is desirable that the flux 13 has a relatively high adhesiveness. Therefore, the Deltalux 527 made by Senju Metal Co., Ltd.
-7 was used. A tin-silver solder having a thickness of 50 [μm] is used for the solder film 8 and is punched out to a diameter of 80 [μm].
A tin-silver solder disk 10 was formed. The heating of the LSI adsorption and pressurizing means 1 was set at 250 to 300 ° C. The LSI chip 12 was pressed against the wiring board 5 at 0.5 kg. At this time, nitrogen gas was blown into the gap between the LSI chip 12 and the wiring board 5 to reduce the oxygen concentration to 500 ppm or less.

[Second Embodiment] Next, a second embodiment of the present invention will be described with reference to FIG. This embodiment is characterized in a process of supplying solder to the pads for mounting the LSI before removing the defective LSI chip and before attaching the replacement LSI chip. Hereinafter, this solder supply step will be described.

FIG. 2A shows the same LS as in the first embodiment.
This shows a state in which a defective LSI chip has been removed from above the wiring board 5 by the I chip removal step. First, as shown in FIG. 2B, a flux 13 is applied to a ceramic substrate 14 prepared separately from the wiring substrate 5. Subsequently, on the ceramic substrate 14, the LSI disposed on the wiring substrate 5 is used.
The solder disk 10 is applied by a micro-press method in correspondence with the position of the mounting pad 11, and the flux 13
Adhere to.

Thereafter, as shown in FIG. 2C, the surface of the ceramic substrate 14 to which the solder disk 10 is not bonded is sucked by the LSI suction and heating means 1 and
And the LSI mounting pad 11 are opposed to the wiring board 5 so as to face each other. Then, the LSI mounting pad 11 and the solder disk 10 are aligned, and the LSI suction and heating means 1 is lowered to bring the solder disk 10 into contact with the LSI mounting pad 11. In this state, the LSI suction heating means 1 is heated, and at the same time, pressure is applied to the wiring board 5 side to melt the solder disk 10. As a result, FIG.
As shown in (d), the solder disk 10 is transferred to the LSI mounting pad 11, and the solder is supplied to the LSI mounting pad 11.

According to this, after confirming the arrangement position of the plurality of solder disks 10 attached to the ceramic substrate 14, each of the plurality of solder disks 10
The solder can be supplied to the SI mounting pad 11, and the solder can be easily supplied even in a situation where the already mounted components are densely packed around the chip reattachment position. Further, a nitrogen gas may be blown to the joint portion when the solder is melted. Thereby, the surface of the solder transferred to the LSI mounting pad 11 side can be smoothed.

Here, as a more specific example of the present embodiment, the ceramic substrate 14 was 0.3 [mm] thick. As the ceramic substrate 14 used in the present embodiment, an aluminum nitride substrate having good thermal conductivity is preferable. The flux 13 is made of Deltalux 5 similarly to the first embodiment.
27-7 was used. The solder disk 10 formed by the micropress method was made of tin silver solder and had a diameter of 80 [μm]. Heating by the LSI heating and pressing means 1 is 250 to 30
Was 0 [℃].

[Third Embodiment] Next, a third embodiment of the present invention will be described with reference to FIG. This embodiment has a feature in the step of supplying solder to the LSI mounting pads 11 as in the second embodiment, and particularly relates to a method of re-supplying solder to fine pitch LSI mounting pads. Hereinafter, the solder supply step will be described.

FIG. 3A shows the same LS as in the first embodiment.
The state where the defective LSI chip is removed from the wiring substrate 5 by the I chip removal method is shown. First, as shown in FIG. 3A, a metal flat plate 15 thicker than the LSI mounting pad 11 is arranged between the LSI mounting pads 11. Subsequently, similarly to the second embodiment, after applying the flux 13 to the ceramic substrate 14, the solder disk 10 is bonded (FIG. 3B). Further, as in the second embodiment, L
Ceramic substrate 14 held by SI adsorption heating means 1
Is opposed to the wiring board 5, and the solder disk 10 and the LSI
The LSI suction heating means 1 is lowered until the mounting pads 11 come into contact with the mounting pads 11 (FIG. 3C). Then, the heating and pressurization of the LSI adsorption and heating means 1 causes the solder disk 10 to
The image is transferred to the SI mounting pad 11 (FIG. 3D).

At this time, the thickness of the metal plate 15 sandwiched between the ceramic substrate 14 and the wiring substrate 5 keeps the distance between the ceramic substrate 14 and the wiring substrate 5 from approaching a certain value or more. High pitch LSI
The solder disk 10 transferred onto the mounting pads 11 can be held without being deformed more than necessary. Also,
Nitrogen gas may be blown to the joint when the solder is melted. Thereby, the surface of the solder transferred to the LSI mounting pad 11 side can be smoothed.

Here, a more specific example of this embodiment will be described. The above embodiment is particularly effective when the pitch of the LSI mounting pad 11 is as fine as 120 [μm] or less. The metal plate 15 has a thickness of 30 [μ
m]. As the ceramic substrate 14, an aluminum nitride substrate (alumina substrate) was used. The flux 13 has a Deltalux 5 as in the first embodiment.
27-7 was used. The diameter of the solder disk 10 is 80 [μm] using tin-silver solder. However, the diameter and thickness of the solder disk 10 need to be changed according to the area of the LSI mounting pad 11. The heating of the LSI adsorption heating means 1 is 250 to
The temperature was 300 ° C., and the pressure was 0.5 to 1.0 kg.

The embodiments described above are particularly suitable for repairing flip-chip type semiconductor devices using gold bumps.

Here, in each of the above embodiments, after the chip reattachment step is completed, a flux cleaning step may be performed. Spraying of the nitrogen gas may be performed from two directions or four directions facing each other with respect to the joint portion. According to this, the solder surface is particularly uniformly smoothed without unevenness.
The metal plate is preferably set to have a thickness of 20 to 50 [μm].

[0037]

Since the present invention is constructed and functions as described above ,

According to the first aspect of the present invention, since the solder pieces punched out from the solder disk are supplied to the chip mounting disk, even when there are already mounted components around the chip re-attachment position, the chip mounting pads can be used. The solder pieces can be supplied to the corresponding desired positions, and the repair work can be facilitated.

According to the second aspect of the present invention, since the solder pieces once adhered to the predetermined position on the heat conductive substrate are transferred to the chip mounting pads of the wiring board, the plurality of solder pieces adhered to the heat conductive substrate are transferred. After confirming the placement position of the chip, multiple solder pieces can be supplied to each chip mounting pad with high precision at once, and in a situation where the already mounted components are densely packed around the chip re-attachment position. However, it is possible to easily supply the solder.

According to the third aspect of the present invention, the surface of the solder transferred to the chip mounting pad side can be smoothed by blowing a nitrogen gas to the joint portion when the solder is melted, and the chip can be reattached. It can be done easily.

According to the fourth aspect of the present invention, since the metal plate having a predetermined thickness is arranged between the heat conductive substrate and the wiring substrate, the thickness of the metal plate sandwiched between the heat conductive substrate and the wiring substrate is reduced. Thereby, the distance between the heat conductive substrate and the wiring substrate is held so as not to be closer than a certain value, and the solder pieces transferred onto the fine pitch chip mounting pads can be held without being deformed more than necessary. it can. Therefore, the repair work of the flip chip type semiconductor device employing the fine pitch chip mounting pads can be facilitated.

The present invention is particularly effective for repairing a flip-chip type semiconductor device using gold bumps. A flip-chip type employing gold bumps which could not be repaired and discarded because re-solder could not be supplied in the past. It is possible to provide an unprecedented method of repairing a flip-chip type semiconductor device which can repair the semiconductor device, improve the yield of the flip-chip type semiconductor device and contribute to the reduction of industrial waste.

[Brief description of the drawings]

FIG. 1 is a state diagram showing a flow of a repair process according to a first embodiment of the present invention. FIG. 1A shows a state before a defective chip is removed, and FIG.
(C) is a solder supply step, and FIG.
FIG. 1E shows the state after reattachment of the chip, and FIG. 1F shows the state after reattachment of the chip.

FIG. 2 is a state diagram showing a flow of a solder supply step in a second embodiment of the present invention. FIG. 2 (a) shows a state after a defective chip is removed, and FIG. FIG. 2C shows the state after the transfer of the solder piece from the heat conductive substrate to the wiring board, and FIG. 2D shows the state after the transfer of the solder piece.

FIG. 3 is a state diagram showing a flow of a solder supply step according to a third embodiment of the present invention. FIG. 3 (a) is an arrangement of a metal plate after a defective chip is removed, and FIG. 3 (b) is a heat conductive substrate. FIG. 3 (c) shows a state after the solder piece is transferred from the heat conductive substrate to the wiring board, and FIG. 3 (d) shows a state after the solder piece is transferred.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Adsorption heating means 2 Defective LSI chip 3 Non-defective LSI chip 4 Solder connection part between LSI chip and wiring board 5 Wiring board 6 Sealing resin 7 Punch 8 Solder film 9 Dice 10 Solder disk (solder piece) 11 LSI mounting pad ( Chip mounting pad) 12 New LSI chip (alternative semiconductor) 13 Flux 14 Ceramic substrate (thermally conductive substrate) 15 Metal plate

Claims (4)

(57) [Claims] A package for chip mounting provided on a wiring board.
Melt the solder joining the flip-chip type semiconductor
Remove the flip-chip type semiconductor from the wiring board
Removal process and applying solder to the chip mounting pad
Solder supply process to be applied and applied to the chip mounting pad
After melting the solder, substitute semiconductor
Chip type having a reattaching step of joining to a pad
In the method of repairing a semiconductor device, the solder supply step may include flushing the chip mounting pad.
The first step of applying the soldering and punching from the solder film
Mounting the chip with the removed solder piece via the flux
And a second step of adhering to the pad for use.
A method for repairing a flip-chip type semiconductor device. 2. A chip mounting package provided on a wiring board.
Melt the solder joining the flip-chip type semiconductor
Remove the flip-chip type semiconductor from the wiring board
Removal process and applying solder to the chip mounting pad
Solder supply process to be applied and applied to the chip mounting pad
After melting the solder, substitute semiconductor
Chip type having a reattaching step of joining to a pad
In the method for repairing a semiconductor device, the solder supply step is provided separately from the wiring board.
The first step of applying flux to the thermally conductive substrate,
Solder pieces punched from solder film are applied to the wiring board
According to the arrangement of the provided chip mounting pads,
Second step of attaching to the heat conductive substrate via the flux
And the solder pieces attached to the heat conductive substrate
The heat conductive substrate so as to be in contact with the mounting pad.
The heat conductive substrate is heated by applying heat to the heat conductive substrate.
And a third step of melting the piece.
Repair method for a flip-chip type semiconductor device. 3. When the solder piece is melted,
It is characterized by blowing nitrogen gas toward the melting point
A method of repairing the flip-chip type semiconductor device according to claim 2.
Law. 4. The heat conductive substrate is opposed to the wiring substrate.
When the chip is mounted between the chip mounting pads.
The mounting pad and the solder piece are in contact with each other.
A metal plate having a thickness is arranged.
3. The method for repairing a flip-chip type semiconductor device according to item 2.