JP2887940B2 - Lead for semiconductor device and processing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead for a semiconductor device connected to an electrode of a semiconductor element (chip) such as an LSI and a VLSI, and a method of processing the lead.

[0002]

2. Description of the Related Art Conventionally, in a mounting technology of a semiconductor device having a super multi-pin structure in which semiconductor elements such as LSI and VLSI are incorporated, a wire bonding method, a TAB (Tape-au
A tomated-bonding method and an FC (flip chip) method are known, but in an actual production line, a wire bonding method or a TAB method is often adopted in terms of mounting accuracy and ease of handling.

In the wire bonding method, a bump (protrusion) formed on a bonding pad (electrode) on a chip and an inner lead (metal thin plate) of a lead frame (lead for a semiconductor device) are connected by a bonding wire. It is a method.

In the TAB method, a chip is inserted into a device hole of a film carrier tape (lead for a semiconductor device), and a bonding pad provided on the chip and a tip end of an inner lead protruding into the device hole are formed. Various methods have been proposed and used so far.

For example, as a bump bonding method,
(A) A method of forming a bump on a bonding pad on a chip and connecting the bump to the tip of the inner lead by thermocompression bonding or ultrasonic waves; (b) Forming a bump on the tip of the inner lead by a transfer method A method of connecting the bumps to the bonding pads on the chip by thermocompression bonding is generally used.

The bumpless bonding method includes (c) a method of forming a projection at the tip of an inner lead by etching and connecting the projection to a bonding pad on a chip. In general, a method of bending the wire into a substantially S-shape and connecting the tip portion to a bonding pad on the chip by thermocompression bonding is used.

[0007] The above-mentioned bending of the inner lead is performed by previously machining the tip of the inner lead of the lead frame or the film carrier tape by a molding machine or by cutting the lead frame or the film carrier tape one chip at a time. At the same time, it is common to simultaneously machine the tip of the inner lead with a molding machine or the like.

[0008]

However, the above-mentioned lead frame and the inner lead of the film carrier tape are soft and thin, having a thickness of about several tens of μm, so that they are easily broken, deformed, or damaged. there were. Further, the above-described bending process of the inner lead cannot absorb variations on the inner lead side, and has a disadvantage that dimensional accuracy is reduced.

Therefore, when mounting, the accuracy of alignment of the inner leads is poor, and connection failure due to breakage or deformation of the inner leads is apt to occur, which is a main factor of lowering the yield of products (semiconductor devices) and increasing costs. Had become. In addition, there is another problem that the working efficiency is reduced due to difficulty in handling the inner lead.

Further, in bending the inner lead, it is necessary to bend the tip of the inner lead with high accuracy. However, it is difficult to machine the inner lead into a predetermined shape with required accuracy. There was also a problem that it became increasingly difficult to respond to the line in a timely manner.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a semiconductor device lead and a method for processing the same, which can effectively solve the above-mentioned drawbacks and problems.

[0012]

In order to solve the above-mentioned problems, the present invention employs the following semiconductor device leads and a method of processing the same.

That is, as the lead for a semiconductor device according to the first aspect, a heat-shrinkable resin is applied to the inner surface of a concave portion of a thin metal plate to be bent, and the heat-shrinkable resin is heated to shrink, thereby forming the metal. It is characterized by bending a thin plate.

According to a second aspect of the present invention, there is provided a method of processing a lead for a semiconductor device, wherein a heat-shrinkable resin is applied to an inner surface of a concave portion of a thin metal plate to be bent, and then the heat-shrinkable resin is heated to shrink. And bending the thin metal plate.

The heat-shrinkable resin preferably shrinks in volume when heated, has high mechanical strength, is unlikely to undergo thermal decomposition or thermal deterioration, and can withstand the temperature during resin molding.

[0016]

In the semiconductor device lead according to the first aspect of the present invention, the processing accuracy of the thin metal plate is improved, and the mechanical strength of the bent portion of the thin metal plate is improved.

According to a second aspect of the present invention, the thin metal plate is bent into a predetermined shape with high accuracy.

[0018]

Embodiments of the present invention will be described below.

First, an inner lead (a thin metal plate) of a film carrier tape (a lead for a semiconductor device) according to an embodiment of the present invention will be described with reference to FIG.

The film carrier tape 1 is a film 2 having a thickness of 75 to 125 μm made of a material such as polyimide resin, glass-containing epoxy resin, BT resin, or polyester. Circuits are formed on the surface, and sprockets are provided at both ends along the longitudinal direction. Holes 3,... Are formed at equal intervals, and a device hole 4 for chip insertion is formed in the center. The inner leads 5 are formed on the film 2 so as to project into the device holes 4.

The inner leads 5,... Are formed by, for example, attaching copper foil on the film 2 and etching the copper foil to form thin wires. One end 5a of the device hole 4
And the other end 5b protrudes from the periphery toward the device hole 4.

As shown in FIG. 2, the other end 5b of the inner lead 5 is bent vertically downward in a substantially S-shape.
A heat-shrinkable heat-shrinkable resin 7 is adhered to the concave portion 6 on the upper surface side, and a heat-shrinkable heat-shrinkable resin 9 is also adhered to the lower surface side concave portion 8.

As the heat-shrinkable resins 7, 9, polyimide, aromatic polyamide, polybenzimidazole and the like are preferably used.

The above-mentioned heat-shrinkable resins 7 and 9 are liquid at room temperature but shrink in volume when heated.
Any material that has high mechanical strength, is unlikely to undergo thermal decomposition or thermal deterioration, and can withstand the temperature during resin molding, and more preferably a heat-curable type can be used.

If the thickness of these heat-shrinkable resins 7 and 9 is too small, sufficient tensile strength cannot be obtained, so that the inner lead 5 is not bent. Since a thick resin layer is formed on the inner lead 8, the resin layer hinders the bending of the inner lead 5, so that sufficient bending cannot be performed. Therefore, the thickness of the heat-shrinkable resin used is limited by the properties of the heat-shrinkable resin. For example, in the case of polyimide, the optimal thickness range is 3-7.
0 μm.

Next, a method for processing the inner lead will be described with reference to FIG. First, at room temperature, the leading ends 11a of the inner leads 11,.
A liquid heat-shrinkable resin 14 is provided on each of a portion 12 to be a concave portion on the upper surface side and a portion 13 to be a concave portion on the lower surface side.
15 (FIG. 3A), and heat-shrinkable resins 14 and 15
The solvent contained in is volatilized.

Next, the film carrier tape 1 is left in a thermostat set at a predetermined temperature for a predetermined time, and the heat-shrinkable resins 14 and 15 are heated and polymerized. The temperature and time at this time are, for example, 80 ° C., 15
0 ° C, 200 ° C, and 350 ° C for 30 minutes each.

As the polymerization proceeds, the heat-shrinkable resins 14,1
5, the volume 12 contracts, and the portion 12 to be a concave portion and the portion 13 to be a concave portion of the distal end portion 11a are bent inward (FIG. 9B).

When the polymerization is completed, the heat-shrinkable resin 1
4 and 15 are hardened, and the front end portion 11a is bent into a predetermined substantially S-shaped shape ((c) in the same figure) to form the inner lead 5.

As shown in FIGS. 4 and 5, the inner lead 5 is mounted on the bump 23 of the bonding pad 22 of the chip 21 whose other end 5b is inserted into the device hole 4, and is thermocompression-bonded or super-pressed. The sound is connected to the bumps 23.

As described above, according to the film carrier tape 1 of the above embodiment, the other end 5 of the inner lead 5
Since the heat-shrinkable resin 7 is stuck to the recess 6 on the upper surface side of b and the heat-shrinkable resin 9 is stuck to the recess 8 on the lower surface side, the processing accuracy of the inner lead 5 is improved. Thus, the mechanical strength of the bent portion of the inner lead 5 can be improved.

Therefore, the accuracy of the alignment of the inner leads 5 at the time of mounting can be improved, and the connection failure due to the bending or deformation of the inner leads 5 can be greatly reduced, and the product (semiconductor device) can be manufactured. Yield can be improved and low cost can be realized.

According to the method of processing the inner lead 5 of the above embodiment, each of the tip 12a of the inner leads 11,... Since the heat-shrinkable resins 14 and 15 are applied, and then the heat-shrinkable resins 14 and 15 are heated and shrunk to bend the inner leads 11,..., The inner leads 11,. Can be tuned.

Further, since the heat-shrinkable resins 7 and 9 have a constant shrinkage ratio, the bending of the inner lead 11 can be performed with high accuracy and efficiency only by controlling the thickness of the coating film. Therefore, the bending process can be performed with high precision regardless of the variation in the width of the inner lead 11, and it is possible to cope with a fine pitch and a thinner inner lead.

Also, by changing the application position of the heat-shrinkable resins 7 and 9, various effects such as bending can be achieved.

As described above, it is possible to provide the film carrier tape 1 which is not easily broken or deformed and has high dimensional accuracy and a method for processing the same.

[0037]

As described above, according to the first aspect of the present invention,
According to the lead for a semiconductor device described above, the metal sheet is bent by applying a heat-shrinkable resin to the inner surface of the concave portion to be bent of the metal sheet, and heating and shrinking the heat-shrinkable resin. Therefore, the processing accuracy of the metal sheet can be improved, and the mechanical strength of the bent portion of the metal sheet can be improved.

Therefore, the accuracy of positioning of the metal sheet at the time of mounting can be improved, the connection failure due to the bending or deformation of the metal sheet can be greatly reduced, and the yield of the product (semiconductor device) can be reduced. The cost can be improved and the cost can be reduced.

According to the semiconductor device lead processing method of the present invention, a heat-shrinkable resin is applied to the inner surface of the concave portion of the thin metal plate to be bent, and then the heat-shrinkable resin is heated to shrink. Then, it was decided to bend the metal sheet,
The thin metal plate can be bent into a predetermined shape with high precision.

Further, the bending of a thin metal plate can be performed with high accuracy and efficiency simply by controlling the thickness of the heat-shrinkable resin coating film. Therefore, the bending can be performed with high accuracy regardless of the variation in the width of the metal thin plate, and it is possible to cope with a fine pitch and a thinner inner lead.

Also, by changing the application position of the heat-shrinkable resin, various effects such as bending can be achieved.

As described above, it is possible to provide a semiconductor device lead with high dimensional accuracy which is not easily broken or deformed, and a method of processing the same.

[Brief description of the drawings]

FIG. 1 is a partial perspective view showing a film carrier tape (lead for a semiconductor device) of the present invention.

FIG. 2 is a partial side view showing an inner lead of the film carrier tape of the present invention.

FIG. 3 is a process diagram showing a method for processing an inner lead according to the present invention.

FIG. 4 is a partial perspective view showing a mounted state of the film carrier tape of the present invention.

FIG. 5 is a partial side view showing a bonding state between an inner lead and a chip according to the present invention.

[Description of Signs] 1 Film carrier tape (lead for semiconductor device) 2 Film 3 Sprocket hole 4 Device hole 5 Inner lead (metal thin plate) 6,8 Depression 7,9 Heat shrinkable resin 11 Inner lead (metal thin plate) 12, 13 Parts to be concave parts 14, 15 Heat-shrinkable resin

Claims (2)

(57) [Claims] 1. A heat-shrinkable resin is applied to an inner surface of a concave portion of a metal sheet to be bent, and the heat-shrinkable resin is heated and shrunk to bend the metal sheet. Lead for semiconductor device. 2. A semiconductor device wherein a heat-shrinkable resin is applied to an inner surface of a concave portion of a metal sheet to be bent, and then the heat-shrinkable resin is heated and shrunk to bend the metal sheet. Method of processing lead