JPH09331148A - Flip-chip mounting to flexible wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid generating a positional deviation of the electrode joints between a flexible wiring board and a semiconductor bare chip, and peeling off the electrode joints without the need for the complicated holding means for the bare chip. SOLUTION: In a flip-chip mounting method, wherein a semiconductor bare chip 1 is directly loaded on a flexible wiring board 3 for conforming to lead patterns 3a on the flexible wiring board 3, and, after conductive projections 2 of the bare chip 1 are made an electrical connection with the lead patterns 3a, an insulative resin is injected between the board 3 and the bare chip 1 to seal with resin to the flexible wiring board, before the projections 2 are electrically connected with the patterns 3a, a bonding agent 6 for temporarily fixing is fed and cured in a part encircled with the projections 2 and the patterns 3a and the bare chip 1 is temporarily fixed on the board 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flip chip mounting method for mounting a semiconductor bare chip on a flexible wiring board.

[0002]

2. Description of the Related Art Conventionally, in a method for mounting a semiconductor chip on a printed wiring board, a flip chip mounting method for bonding the semiconductor chip to the printed wiring board has been used because of its advantages in cost and space. There are various methods for flip-chip mounting, and as a relatively low-cost flip-chip mounting method, there is one using a conductive adhesive. This technique is shown in FIG. 6 and FIG.
This will be described below. In FIG. 6, the bare semiconductor chip 10
1. In the peripheral portion of 1, the conductive protrusions 102 serving as a plurality of surface electrodes are provided.
Is protruding. The conductive protrusions 102 are usually gold bumps and have a height of 20 to 50 μm. Also,
The distance between the conductive protrusions 102 is set to 120 to 200 μm, as shown in FIG.

First, the conductive adhesive 105 is thinly spread on a flat plate, the conductive protrusions 102 of the semiconductor bare chip 101 are placed thereon, and the conductive adhesive 105 is collectively attached. Next, as shown in FIG. 7, the conductive protrusions 102 of the semiconductor bare chip 101 are placed in alignment with the lead patterns 103a of the printed wiring board 103. After this,
The conductive adhesive 105 is cured by heating from the lower surface of the printed wiring board 103. Further, for reinforcement and protection of the semiconductor bare chip 101, an insulating resin 104 is injected between the semiconductor bare chip 101 and the printed wiring board 103 and heat-cured. As a result, as shown in FIG.
The mounting work of the semiconductor bare chip 101 on the printed wiring board 103 is completed.

Since a hard substrate is usually used for the printed wiring board 103, the semiconductor bare chip 101 in which a conductive adhesive 105 is applied to the tips of the conductive protrusions 102 is used.
The semiconductor bare chip 101 is simply placed on the printed wiring board 103 by the viscous force of the conductive adhesive 105.
Since the printed wiring board 103 is formed on a flat surface, the specific conductive protrusions 102 do not have to be separated from the lead pattern 103a. Further, it can be inserted into a high-temperature heating furnace as it is and cured by heating. Further, even after the conductive adhesive 105 is hardened and even in the process of reinforcement by resin sealing, the printed wiring board 103 is hardly deformed, and the electrode joint portion between the conductive protrusion 102 and the lead pattern 103a may be peeled off. There is no.

[0005]

However, the above-mentioned prior art has the following problems. That is, when the above-mentioned conventional technique is applied to a flip-chip mounting method for a flexible wiring board, the adhesive force cannot withstand the flexure of the flexible wiring board only by curing the conductive adhesive, and the electrode bonding portion is peeled off. . If you inject an insulating resin and seal and harden it, you can obtain sufficient strength.
Peeling during the process cannot be dealt with. In order to prevent peeling during this process, it is necessary to position the semiconductor bare chip on the flexible wiring board and continue to hold it until the sealing resin is cured from the time when the semiconductor bare chip is placed on the flexible wiring board. is there.

For this reason, if the semiconductor bare chip is mounted by continuously holding the semiconductor bare chip in one mounting apparatus in all steps, the cycle time until the mounting is completed becomes long, and the production efficiency is deteriorated. . On the other hand, in the case of a line knitting system that sequentially carries out each process instead of mounting in one mounting device,
The flexible wiring board is placed on a carrier such as a pallet for transportation.At this time, only the viscous force of the conductive adhesive adhering to the conductive protrusions causes the conductive wiring pattern of the flexible wiring board and the semiconductor bare chip to be electrically conductive. It is impossible to maintain the position with the elastic protrusion, and therefore a pressing means for pressing the upper surface of the semiconductor bare chip is required.

The pressing means should not move the positions of the flexible wiring board and the semiconductor bare chip even if the pallet or the like is shaken during the transportation by the conveyor of the transportation platform or the like, and the lead pattern of the flexible wiring board is used. Must be removed during the joint inspection between the
At the time of supplying the sealing resin thereafter, reproducibility of pressing is required so that there is no positional deviation again, and therefore the carrier table equipped with such pressing means must have a complicated and expensive structure. There is a problem.

The present invention has been made in view of the above-mentioned conventional problems, and the object of the invention according to claim 1 is to eliminate the need for complicated holding means and to provide an electrode joint between a flexible wiring board and a semiconductor bare chip. To provide a flip chip mounting method of a semiconductor bare chip on a flexible wiring board which avoids the positional deviation and peeling.

[0009]

In order to solve the above problems, the invention according to claim 1 directly mounts a semiconductor bare chip according to the lead pattern of a flexible wiring board,
After electrically connecting the conductive protrusions of the semiconductor bare chip and the lead pattern, an insulating resin is injected between the flexible wiring board and the semiconductor bare chip to perform resin sealing. Flip chip mounting on a flexible wiring board. In the method, before electrically connecting the conductive protrusion and the lead pattern, a temporary fixing adhesive is supplied to the portion surrounded by the conductive protrusion and the lead pattern to cure the semiconductor bare chip. And the flexible wiring board are temporarily fixed.

In the operation of the invention according to claim 1, before the electrically conductive protrusion and the lead pattern are electrically connected, a temporary fixing adhesive is applied to the portion surrounded by the electrically conductive protrusion and the lead pattern. By supplying and curing and temporarily fixing the semiconductor bare chip and the flexible wiring board, there will be no displacement or peeling between the respective members due to handling after the temporary fixing.

[0011]

First Embodiment FIG. 1 shows a first embodiment of the invention and is a process diagram showing a state in which a semiconductor bare chip and a flexible wiring board are temporarily fixed. In FIG. 1, the semiconductor bare chip 1 is the semiconductor bare chip 1 shown in FIG.
The structure is the same as that of No. 01, and the conductive protrusions 2 are provided on the periphery. The flexible wiring board 3 also has the same lead pattern 3a as the lead pattern 103a, as shown in FIG.

First, the flexible wiring board 3 is placed on a carrier table 7 having a flat upper surface, and the flexible wiring board 3 is heated at the center of the portion where the semiconductor bare chip 1 surrounded by the lead pattern 3a is mounted. A temporary fixing adhesive 6 made of a curing type epoxy adhesive, with a diameter of 0.5 mm
Apply to a degree. Next, the semiconductor bare chip 1 in which the conductive adhesive 5 is applied to the conductive protrusions 2 in advance is mounted in conformity with the lead pattern 3a of the flexible wiring board 3 (working time is about 5 seconds). The process diagram of the state at this point is shown in FIG.
It is. As a result, the temporary fixing adhesive 6 previously applied to the flexible wiring board 3 is spread at the center of the lower surface of the semiconductor bare chip 1 and is interposed between the semiconductor bare chip 1 and the flexible wiring board 3. It On the other hand, the conductive adhesive 5 applied to the tips of the conductive protrusions 2 also matches the lead patterns 3a of the flexible wiring board 3, and the conductive protrusions 2 and the lead patterns 3a are in electrical contact with each other. It becomes a state.

Next, the portion of the flexible wiring board 3 indicated by the arrow A (the lower portion of the portion where the temporary fixing adhesive 5 is interposed) is heated for a few seconds (1 to 10 seconds) and cured.
For this heating, the diameter is 1 m from the taper hole 7a of the carrier table 7.
Means such as applying a heater having a tip of about m or irradiating laser light is used. When the temporary fixing adhesive 5 is cured, the semiconductor bare chip 1 and the flexible wiring board 3 are temporarily fixed and integrated. Next, the flexible wiring board 3 to which the semiconductor bare chip 1 is temporarily fixed becomes free to be transported and is sent to the inspection device, where the bonding inspection and the performance inspection are performed while pressing the semiconductor bare chip 1 from above.
Further, it is sent to another heating furnace and a mounting apparatus, and the conductive adhesive 5 at the electrode joint portion is cured (about 1 hour) and resin-sealed by the insulating resin 4 (not shown) as in the conventional technique (about 1 hour). Three
Time) and. This completes the mounting of the semiconductor bare chip 1 on the flexible wiring board 3.

According to the first embodiment of the present invention, since the flexible wiring board and the semiconductor bare chip are temporarily fixed in a short time, the flexible wiring board and the semiconductor bare chip are sent to the next step without requiring any complicated holding means, and the resin sealing work or the like is performed. This makes it possible to avoid peeling and displacement of the electrode joint. Further, it takes a long time to cure the conductive adhesive and the insulating resin for sealing, but since these operations can be collectively performed by a device different from the mounting device, The efficiency of the entire process is improved. Furthermore, since the gap between the semiconductor bare chip and the flexible wiring board can be maintained by hardening the adhesive for temporary fixing, it is easy to inject the insulating resin, and the wraparound into the gap is facilitated. The mounting method according to the first embodiment of the present invention is effective for mounting a relatively small semiconductor bare chip.

In the first embodiment of the present invention, the temporary fixing adhesive is applied to the flexible wiring board, but it may be applied to the center of the lower surface of the semiconductor bare chip to be interposed. Further, depending on the size of the semiconductor bare chip, the temporary adhesive may be applied to several places. Further, the temporary fixing adhesive may be replaced with a heat-curing type and may be a thermoplastic type. Furthermore, depending on the type of conductive adhesive, 20
It may be cured in about 30 seconds, and may be cured in 1 hour or less depending on the type of the sealing insulating resin, and may be appropriately selected depending on the manufacturing conditions.

[0016]

Embodiment 2 of the Invention FIGS. 2 to 3 show Embodiment 2 of the invention. FIG. 2 is a process diagram showing a state in which a semiconductor bare chip and a flexible wiring board are temporarily fixed, and FIG. 3 is a temporary fixing adhesive. 3 is a plan view of the supply nozzle of FIG. Embodiment 2 of the present invention
Is a modification of the method of supplying the temporary fixing adhesive in the mounting method according to the first embodiment of the invention. For other common mounting methods, the same members are designated by the same reference numerals and description thereof is omitted. To do.

In FIG. 2, the semiconductor bare chip 1 is the same as the semiconductor bare chip of the first embodiment of the invention. However, the flexible wiring board 13 has a round hole 13 for supplying a temporary fixing adhesive to the center of the portion where the semiconductor bare chip 1 is mounted, which is surrounded by the lead pattern 13a.
The point that b is provided is different from the flexible wiring board 3 of the first embodiment of the invention. Further, in the mounting apparatus, an arm head 11 for sucking, carrying and pressing the semiconductor bare chip 1 is arranged above the tapered hole 7a of the carrying table 7 so as to be vertically movable and horizontally movable. A nozzle 12 for supplying the temporary fixing adhesive 6 is provided so as to be vertically movable and horizontally movable in conformity with the axial center of the taper hole 7a of the carrier table 7.

As shown in FIGS. 2 and 3, the tip of the nozzle 12 has a structure in which a mandrel 12b is supported by three rims 12c at the center of a cylinder 12a. A hollow portion 12d is formed below the mandrel 12b and is filled with a temporary fixing adhesive 6, and the vertical movement of a plunger (not shown) causes the temporary fixing adhesive 6 to pass through a gap of the rim 12c and move upward. Is intermittently supplied to. The tip of the nozzle 12 is, as shown in FIG. 2, a cylinder 12a and a mandrel 12b.
There is a step B between the semiconductor bare chip 1 and the flexible wiring board 13, and the temporary adhesive 6 to be supplied is provided in a ring shape between the semiconductor bare chip 1 and the flexible wiring board 13.

Next, the mounting method will be described. First, the flexible wiring board 13 is placed on the upper surface of the carrier table 7 so that its round hole 13b is aligned with the tapered hole 7a of the carrier table 7. Next, the semiconductor bare chip 1 is adsorbed by the arm head 11, the semiconductor bare chip 1 is pressed onto the conductive adhesive 5 thinly spread on the flat plate, and the conductive adhesive 5 is attached to the tips of the conductive protrusions 2. Attach. Next, the arm head 11 conveys the semiconductor bare chip 1 onto the flexible wiring board 13 and descends so that the conductive protrusions 2 and the pattern 3a are aligned with each other, and the flexible wiring board 1
The semiconductor bare chip 1 is mounted on the semiconductor chip 3 and pressed and held.

The nozzle 12 is raised from below and stopped at a position where the mandrel 12b at the tip of the nozzle abuts the lower surface of the bare semiconductor chip 1. Next, the temporary fixing adhesive 6 is sprayed from the nozzle 12 to form a ring of the temporary fixing adhesive 6 around the round hole 13b. Descend the nozzle 12,
As in the first embodiment of the invention, the temporary fixing adhesive 6 is evacuated in the horizontal direction and brought close to a heater having a tip with a diameter of about 1 mm, or by irradiating a laser beam.
Cure. Since the subsequent process is the same as that of the first embodiment of the invention, the description thereof will be omitted.

According to the second embodiment of the present invention, in addition to the effect similar to that of the first embodiment of the invention, the temporary fixing work is automatically performed, so that the work can be efficiently performed.
The mounting method according to the second embodiment of the present invention is advantageous for mounting a relatively large semiconductor bare chip.

In the second embodiment of the present invention, an epoxy adhesive is used as the temporary adhesive, and the adhesive is temporarily cured by heating and curing. However, instead of this, a strong instantaneous adhesive is used. You may make it temporarily fix using.

[0023]

Embodiment 3 of the Invention FIGS. 4 to 5 show Embodiment 3 of the invention, FIG. 4 is a process diagram showing a state where a semiconductor bare chip and a flexible wiring board are temporarily fixed, and FIG. 5 is a temporary fixing adhesive. 3 is a plan view of the supply nozzle of FIG. Embodiment 3 of the present invention
Is a modification of the method of supplying the temporary fixing adhesive in the mounting methods of the first and second embodiments of the invention, and other common mounting methods will be described by assigning the same reference numerals to the same members. Is omitted.

In FIG. 4, the semiconductor bare chip 1 is the same as the semiconductor bare chip of the first embodiment of the invention, and the flexible wiring board 13 is the same as the flexible wiring board of the second embodiment of the invention. Further, in the mounting apparatus, arm head 11 for sucking, carrying and pressing semiconductor bare chip 1 is the same as that of the second embodiment of the invention. The nozzle 14 for supplying the temporary fixing adhesive 6 is aligned with the axial center of the taper hole 7a of the carrier table 7,
Similar to the second embodiment of the invention, it is arranged to be vertically movable and horizontally movable.

As shown in FIG. 5, at the tip of the nozzle 14, three branch nozzles 14a are erected from the nozzle body 14b, and the tip of the branch nozzle 14a is provided with a temporary fixing adhesive 6 in directions different by 120 degrees. Is curved outward so that it is ejected. Adhesive 6 for temporary fixing ejected from the branch nozzle 14a
Are semiconductor bare chips 1 at three locations around the round hole 13b.
And the flexible wiring board 13 are temporarily fixed.

Next, a mounting method will be described. From the place where the flexible wiring board 13 is placed on the upper surface of the carrier 7 such that the round hole 13b matches the tapered hole 7a of the carrier 7, the arm head 11 moves the semiconductor bare chip 1 onto the flexible wiring board 13. It is the same as that of the second embodiment of the invention up to the point of pressing and holding it while mounting. Next, the nozzle 14 is raised from below and stopped at the position where the tip of the branch nozzle 14a is exposed on the upper surface of the flexible wiring board 13. Next, the temporary fixing adhesive 6 is sprayed from the nozzle 14 and supplied to the three positions of the temporary fixing adhesive 6 around the round hole 13b. The nozzle 14 is lowered and retracted in the horizontal direction, and as in the first embodiment of the invention, a heater having a tip having a diameter of about 1 mm is brought close to it, or a laser beam is irradiated to the adhesive for temporary fixing. Cure 6 Since the subsequent process is the same as that of the first embodiment of the invention, the description thereof will be omitted.

According to the third embodiment of the present invention, the same effect as that of the second embodiment of the invention can be obtained. further,
If an instant adhesive is used as the temporary adhesive, the mounting device can be simplified and the cycle time can be shortened.

[0028]

According to the first aspect of the present invention, since the positional deviation and the peeling between the respective members do not occur due to the handling after the temporary fixing, the flexible wiring board does not need any complicated holding means. It is possible to avoid positional deviation and peeling of the electrode bonding portion between the semiconductor bare chip and the semiconductor bare chip. When the conductive adhesive is hardened or the insulating resin for sealing is hardened, these operations are collectively performed by a device different from the mounting device, or the conductive adhesive or the insulating resin for sealing is used. By appropriately selecting, the efficiency of the entire process is improved. Furthermore, since the gap between the semiconductor bare chip and the flexible wiring board can be maintained by hardening the adhesive for temporary fixing, it is easy to inject the insulating resin, and the wraparound into the gap is facilitated.

[Brief description of drawings]

FIG. 1 is a process diagram of a state in which a semiconductor bare chip and a flexible wiring board according to a first embodiment of the invention are temporarily fixed.

FIG. 2 is a process diagram of a state in which a semiconductor bare chip and a flexible wiring board according to a second embodiment of the invention are temporarily fixed.

FIG. 3 is a plan view of a provisional adhesive adhesive supply nozzle according to a second embodiment of the invention.

FIG. 4 is a process diagram of a state in which a semiconductor bare chip and a flexible wiring board according to a third embodiment of the invention are temporarily fixed.

FIG. 5 is a plan view of a provisional adhesive adhesive supply nozzle according to a third embodiment of the invention.

FIG. 6 is a schematic configuration diagram of flip chip mounting of a semiconductor bare chip and a printed wiring board according to a conventional technique.

FIG. 7 is a perspective view of a conventional semiconductor bare chip and a printed wiring board.

[Explanation of symbols]

 1 Semiconductor Bare Chip 2 Conductive Protrusion 3 Flexible Wiring Board 3a Lead Pattern 6 Temporary Fixing Adhesive

Claims (1)

[Claims] 1. A semiconductor bare chip is directly mounted in conformity with a lead pattern of a flexible wiring board, electrically conductive connection between the conductive protrusion of the semiconductor bare chip and the lead pattern, and then an insulating resin is applied to the flexible wiring board. In a flip-chip mounting method on a flexible wiring board which is injected between the semiconductor bare chip and resin-sealed, before the electrically conductive protrusion and the lead pattern are electrically connected, the electrically conductive protrusion and the A flip chip mounting method on a flexible wiring board, comprising: temporarily fixing the semiconductor bare chip and the flexible wiring board by supplying an adhesive for temporary fixing to a portion surrounded by the lead pattern and curing the adhesive.