JP2002176131A - Manufacturing method for semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of a defective due to the flow of the wire of a semiconductor device. SOLUTION: In the manufacturing method for the semiconductor device, connecting leads to be used as external terminals of the semiconductor device and a semiconductor chip are connected and sealed with a sealing body. The manufacturing method is provided with a process wherein a lead frame in which the gap between a suspension lead situated in the corner of the sealing body and a connecting lead adjacent to the suspension lead is made uniform to the gap between the connecting leads is used, and the semiconductor chip and inner leads of the lead frame are electrically connected by bonding wires; and a process wherein the semiconductor chip, the bonding wires, the inner leads and the suspension lead are sealed with a resin to form the sealing body. By this constitution, the gap between the suspension lead and the adjacent connecting lead becomes uniform to the gap between other leads, the flow of the resin is not concentrated, the flow of the wire is hard to generate, and a defect such as a short circuit or the like can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly, to a technique which is effective when applied to prevent occurrence of a defect due to deformation of a bonding wire.

[0002]

2. Description of the Related Art A semiconductor device includes a pad electrode of a semiconductor chip in which elements are formed on a semiconductor substrate such as single crystal silicon;
The semiconductor device, the bonding wires and the inner leads are sealed with a sealing body using a sealing resin such as an epoxy resin. .

[0003] Semiconductor devices such as LSIs are equipped with more complicated circuits and their functions are also advanced as the degree of integration is improved. With such advanced functions, the semiconductor device requires more external terminals, and the number of pad electrodes provided on the semiconductor chip and the number of leads of the semiconductor device are correspondingly increased. As a semiconductor device suitable for such a multi-lead configuration, a QFP (Quad) in which a plurality of leads are respectively provided on four sides of a sealing body for sealing a semiconductor chip.
Flat Package) type semiconductor devices are known, and QFP
The semiconductor device of the type has an advantage that when it is mounted on a mounting board, the space around the semiconductor device can be effectively used. As such a QFP type semiconductor device, for example, “VLSI packaging technology (above)” published by Nikkei BP
155 to P164.

[0004]

In order to cope with such an increase in the number of leads, a semiconductor device is required to reduce a lead pitch, which is an interval between leads, and a lead width. Similarly, many pad electrodes are provided on the semiconductor chip due to the high functionality, and the pad pitch, which is the interval between each pad electrode, is also reduced. In general, there are various types of pad electrode pitches of a semiconductor chip. However, in order to improve the number of chips obtained per wafer, it is desirable that the chip size be small. Therefore, the pitch between each pad electrode is set to be smaller. There is a tendency.

[0005] For these reasons, when bonding between the multiple leads and each pad electrode using a wire such as gold, there is a problem that adjacent wires come into contact with each other to cause a short circuit due to the reduced spacing. There is a problem that is likely to occur. Especially in the corner of the semiconductor chip,
Since the wire bonded to the pad electrode extends obliquely with respect to the semiconductor chip, even if the pad pitch is the same, the interval between the wires is reduced, and the tendency is increased.

[0006] Further, in the resin molding after wire bonding, a decrease in the mechanical strength of each lead or a decrease in the wire interval may cause a wire flow in which the wire is deformed due to the flow of the molding resin. There is a problem that a short circuit occurs between adjacent wires.

In addition, in the QFP, the area where the leads are arranged becomes narrower as the semiconductor chip approaches the semiconductor chip mounted in the center. For this reason, if the lead pitch cannot be sufficiently reduced with respect to the pad pitch of the semiconductor chip due to the limit of the processing accuracy of the lead, the tip of the lead cannot be brought close to the semiconductor chip. The wire to be bonded must be long.
When the wire is lengthened in this way, the probability of occurrence of the short circuit or wire flow increases.

[0008] Further, since the mechanical strength of each lead is reduced due to such miniaturization of the lead, the lead is easily deformed by a slight force, and a short circuit is generated by such deformation.

It is an object of the present invention to provide a technique for preventing a short circuit from occurring due to a wire flow in a multi-lead semiconductor device. The above and other problems and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0010]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

In a method of manufacturing a semiconductor device in which a connection lead serving as an external terminal of a semiconductor device and a semiconductor chip are connected and sealed by a sealing body, a suspension lead positioned at a corner portion of the sealing body; Using a lead frame in which the gap between the connection lead adjacent to the suspension lead and the gap between the connection leads is made uniform, and electrically connecting the semiconductor chip and the inner lead of the lead by a bonding wire; Forming a sealed body by resin-sealing the chip, the bonding wires, the inner leads, and the suspension leads.

According to the above-described means, since the gap between the suspension lead and the adjacent connection lead is made uniform with the gap between the other leads, the flow of the resin is not concentrated, and the flow of the wire is less likely to occur. It is possible to prevent occurrence of a defect such as a short circuit.

Hereinafter, embodiments of the present invention will be described. In all the drawings for describing the embodiments, components having the same functions are denoted by the same reference numerals, and repeated description thereof will be omitted.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a plan view showing a QFP type semiconductor device according to an embodiment of the present invention through a sealing body, and FIG. 2 is an enlarged view of a portion a in FIG. It is a partial top view shown.

In the semiconductor device according to the present embodiment, a semiconductor chip 1 in which elements are formed on a semiconductor substrate of single crystal silicon or the like.
Is fixed to the center of the heat spreader 2 by an adhesive layer. Inner leads 3a of leads 3 used for connection with a mounting board or the like are provided on the peripheral portion of the heat spreader 2.
Is fixed by an adhesive layer formed on the entire surface of the heat spreader 2. Here, the heat spreader 2
In order to improve the heat dissipation of the semiconductor device, a lead 3 made of a material having good thermal conductivity, such as a Cu-based material or an Al-based material,
For example, using a Fe-Ni alloy or a Cu alloy, the tips of a plurality of inner leads 3a are arranged over the entire periphery of the semiconductor chip 1 to be mounted. The ends of the inner leads 3a and the pad electrodes 1a, which are external electrodes of the semiconductor chip 1, are electrically connected, for example, by bonding wires 4 mainly made of gold.

The semiconductor chip 1, the heat spreader 2, the bonding wires 4 and the inner leads 3a are sealed by a sealing body 5 made of, for example, an epoxy resin.
The outer lead 3b of the lead 3 extending from the outer shape is formed in a predetermined shape such as a gull wing shape.

The lead 3 is a lead frame in which a plurality of sets are integrated by a frame in a manufacturing process.
After the formation of the sealing body 5, it is cut and separated into independent leads 3. In order to keep the individual semiconductor devices integrated by a plurality of frames even after the cutting and separation, suspension leads 6 are arranged at the four corners of the sealing body 5, respectively. In addition,
The suspension leads 6 are provided to support the sealing body 5 and are not used for electrical connection. With the use of the suspension leads 6, individual semiconductor devices are integrally processed into a plurality of frames to perform automatic conveyance and the like. In the semiconductor device of the present embodiment, the inner lead 3a for electrical connection adjacent to the suspension lead 6 is tapered toward the suspension lead 6 so that the width of the inner lead 3a is increased toward the suspension lead 6, and the inner leads 3a, 3a adjacent at four corners are formed. The gap between them is made uniform with the gap between other inner leads 3a.

FIG. 3 shows a partial plan view of a conventional semiconductor device for reference. In the conventional semiconductor device, the inner leads 3a arranged at the four corners also have the same width as the other inner leads 3a. For this reason, the gap between the inner leads 3a adjacent at the four corners is different from that of the other inner leads 3a.
Will be wider than the gap. As a result, the sealing body 5
When injecting resin for forming the inner leads 3a,
Inner leads 3a, 3 at four corners wider than the gap between 3a
Since the resin flows intensively in the gap between a, a large amount of wire flow has occurred in the bonding wire 4 in this portion.
In the semiconductor device of the present embodiment, since the gap at this portion is made uniform with other gaps, the flow of the resin does not concentrate and the generation of the wire flow can be prevented.

Next, a method of manufacturing the semiconductor device shown in FIGS. 1 and 2 will be described. First, an adhesive layer is applied and formed on the entire surface of the heat spreader 2 in advance.
a is bonded to the heat spreader 2 with an adhesive.
In the case of this embodiment, the adhesive layer was cured and bonded by heat treatment at about 300 ° C. As the adhesive, for example, a thermosetting resin such as an epoxy resin or a phenol resin, or a thermoplastic resin such as a polyethylene resin or a vinyl chloride resin is used. The heat spreader 2 is obtained by processing a thin metal plate by punching or the like.
The coating may be performed before or after the processing, and may be performed only on necessary portions without being applied on the entire surface.

Next, the semiconductor chip 1 is bonded to the semiconductor chip mounting area of the heat spreader 2 with an adhesive layer,
The inner leads 3a and the pad electrodes 1a of the semiconductor chip 1 are electrically connected by the bonding wires 4.

At the stage when the bonding is completed, each of the leads 3 is integrated with one end of the outer lead 3a by a tie bar 7 and the other end by a dam bar 8, as shown in FIG. A set of three lead frames are connected by a frame 9.

The lead frame is sandwiched between an upper mold and a lower mold, and a semiconductor chip 1, a heat spreader 2, an inner lead 3a, a bonding wire 4 and a suspension lead 6 are located in a cavity 10a of the mold (shown by broken lines).
The sealing body 5 is formed by injecting, for example, an epoxy resin from a gate 10b which is a resin injection channel provided in a mold.

Due to the narrow pitch of the leads 3 for increasing the number of terminals, for example, the width of the inner leads 3a is 100 μm.
The pitch of the leads 3 is about 170 μm, the gap between the inner leads 3 a is narrow and close to 70 μm, and the diameter of the bonding wire 4 is also small, about 27 μm. For this reason, the bonding wire 4 is easily deformed by the flow of the resin, and is likely to be short-circuited by contact with another adjacent bonding wire 4.

At the time of this resin injection, in the production of QFP,
The gate 10b is provided at the corner of the cavity 10a, and the resin spreads into the cavity 10a from the corner where the gate 10b is provided. In the semiconductor device of the present embodiment, inner leads 3a, 3
Since the gap between a is uniform with the other gaps, the flow of the resin does not concentrate and the generation of the wire flow can be prevented. In particular, it is possible to prevent the wire from flowing at the corner where the resin flow rate is large where the gate 10b is provided.

On the other hand, in the conventional semiconductor device, 4
The gap between the inner leads 3a adjacent at the corner was wider than the gap between the other inner leads 3a.
As a result, at the time of injecting the resin for forming the sealing body 5, the resin flows intensively in the four corner gaps wider than the other gaps.
A large wire flow occurred in the bonding wire 4 in this portion. In the semiconductor device in which the heat spreader 2 is provided and the tab suspension lead is eliminated, the gap between the inner leads 3a at the corners is further expanded by eliminating the tab suspension lead, so that the resin is more easily concentrated and the wire flow is more likely to occur. Had become.

After resin sealing, the tie bar 7 and the dam bar 8 that integrate the leads 3 are cut to electrically separate the leads 3. Thereafter, the semiconductor device is subjected to a process such as marking or inspection while the sealing body 5 is supported by the suspension leads 6 and a plurality of frames are connected to and integrally formed with the frame 9. Finally, the suspension leads 6 are sealed. The semiconductor device is cut off immediately near the body 5 to separate the semiconductor devices individually, and the outer leads 3b extending from the sealing body 5 of each semiconductor device are formed into, for example, a gull wing shape to complete the semiconductor device.

In the above-described embodiment, the semiconductor chip 1 is mounted on the heat spreader 2. However, as shown in FIG. 5, the semiconductor device in which the semiconductor chip 1 is mounted on the tab 11 also supports the tab 11 on the lead frame. Inner lead 3a for connection adjacent to tab suspension lead 6
The same effect can be obtained by equalizing the gap between.

Normally, in the manufacture of a semiconductor device, the entire number is inspected by an X-ray inspection or the like in the initial stage. However, when the number of defects becomes lower than a predetermined ratio due to the learning of the process or the like, the entire inspection is performed. We conduct sampling inspections using only a part of the samples. Such 100% inspection requires time and cost for inspection. Since the present invention can reduce the occurrence of defects due to wire flow, it can contribute to early abolition of 100% inspection.

As described above, the invention made by the present inventor is:
Although a specific description has been given based on the above-described embodiment, the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the invention.

[0030]

The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows. (1) According to the present invention, since the gap between the suspension lead and the adjacent connection lead is made uniform with the gap between the other leads, there is an effect that the flow of the resin becomes uniform. (2) According to the present invention, the effect (1) has an effect that a wire flow hardly occurs. (3) According to the present invention, the effect (2) has an effect that occurrence of a defect such as a short circuit can be prevented. (4) According to the present invention, the effect (3) has an effect that it is possible to abolish the 100% inspection at an early stage.

[Brief description of the drawings]

FIG. 1 is a plan view showing a semiconductor device according to an embodiment of the present invention.

FIG. 2 is an enlarged partial plan view showing a part a in FIG. 1;

FIG. 3 is a partial plan view showing a conventional semiconductor device.

FIG. 4 is a partial plan view showing a manufacturing step of the semiconductor device according to one embodiment of the present invention;

FIG. 5 is a partial plan view showing a modification of the semiconductor device according to one embodiment of the present invention;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Semiconductor chip, 1a ... Pad electrode, 2 ... Heat spreader, 3 ... Lead, 3a ... Inner lead, 3b ... Outer lead, 4 ... Bonding wire, 5 ... Sealing body,
6 ... hanging lead, 7 ... tie bar, 8 ... dam bar, 9 ... frame, 10a ... cavity, 10b ... gate, 11 ...
tab.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akihiko Kameoka 5-22-1, Kamizuhoncho, Kodaira-shi, Tokyo Inside Hitachi Super-LSI Systems Co., Ltd. (72) Inventor Fujio Ito Tokyo 5-22-1, Josuihoncho, Kodaira-shi Inside Hitachi Ultra SII Systems Co., Ltd. (72) Inventor Hiromichi Suzuki 5-2-1, Josuihoncho, Kodaira-shi, Tokyo Hitachi, Ltd. Within the Semiconductor Group (72) Inventor Takashi Konno 145 Nakajima, Nanae-cho, Kameda-gun, Hokkaido Inside Hitachi Hokkai Semiconductor Co., Ltd. Reference) 5F067 AA10 AB03 BD05 DE01

Claims (1)

[Claims] 1. A method of manufacturing a semiconductor device in which a connection lead serving as an external terminal of a semiconductor device and a semiconductor chip are connected to each other and sealed by a sealing body, wherein a suspension lead positioned at a corner portion of the sealing body is provided. Electrically connecting the semiconductor chip and the inner lead of the lead with a bonding wire by using a lead frame in which the gap between the connection lead adjacent to the suspension lead and the gap between the connection lead are made uniform. , Semiconductor chips, bonding wires, inner leads,
Forming a sealing body by resin-sealing the suspension lead.