JPH01297833A - Semiconductor device - Google Patents

Abstract

PURPOSE:To reduce material and processing costs and improve the yield by forming a bump at the tip of a lead by use of plasticity processing. CONSTITUTION:The tip of a lead 1A of a thickness t is rendered to plasticity processing to form a protruding bum 2A of height h, and width W. The bump 2A is then subjected to Au-plating as thick as 1-2mum. With the construction, material and processing costs are reduced with the good yield, compared with prior art. The lead bump 2A so formed is brought into close contact with an Al pad 3 on a semiconductor chip 5 and heated to complete a semiconductor device.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a semiconductor device in which a semiconductor chip is mounted on a tape by tape automated bonding (hereinafter referred to as TAB method), and particularly relates to a semiconductor device in which a semiconductor chip is mounted on a tape by tape automated bonding (hereinafter referred to as TAB method). The present invention relates to a semiconductor device that is oriented toward reduction in power consumption.

[Prior Art] Conventionally, a semiconductor device is known in which a semiconductor chip is mounted on a tape by the TAB method.

Methods for connecting leads to semiconductor chips in this type of semiconductor device can be broadly classified into two types. One is to form a protrusion on the semiconductor chip and connect a lead to the protrusion, and the other is to form a bump on the lead and connect the bump to the semiconductor chip. be.

Details of the latter connection method will be explained using FIGS. 6 and 7.

FIG. 6 is a plan view showing an example of a conventional semiconductor device in which a semiconductor chip is mounted on a tape by the TAB method;
The figure is an enlarged side view showing the main part in FIG. 6 (before the leads are connected).

In the figure, 8 is a tape, 5 is a semiconductor chip mounted on this tape 8 (details will be described later), and 1 is a lead connected to this semiconductor chip 5 (details will be described later).

The semiconductor chip 5 has aluminum pads 3 for lead connection on its upper surface, and the rest of the upper surface is covered with a surface protection film 4. The lead 1 has a bump portion 2 formed at its tip, and its dimensions are, for example, lead plate thickness t = 30 to 100 μm, bump portion height h = 30 μm.
~50ILm, bump width w=about 100 μm. The manufacturing method of this lead 1 is as follows:
A resist is applied to a portion having a bump width W, and etching is performed to dissolve the portion other than the bump portion 2 by an amount corresponding to the bump portion height h, and then the resist is removed. Then, the bump portion 2 is plated with gold.

The bump portion 2 of the lead 1 thus formed was heat-pressed onto the aluminum pad 3 of the semiconductor chip 5 via the gold plating layer, thereby connecting the lead 1 to the semiconductor chip 5.

Incidentally, related devices of this type include, for example, "Bumped TAB bonding method" Electronic Materials, vo.
l124. No.5. Examples include pp72 to 76.

[Problems to be Solved by the Invention] The above-described conventional method for connecting leads to a semiconductor chip does not take into account the following points.

The former connection method adds an extra process for forming protrusions after the semiconductor chip is completed, which not only increases the cost of the semiconductor device but also causes a decrease in yield.

The latter connection method involves reducing the wall thickness by etching the portions of the leads other than the bump portions, which has the problem of increased material costs and etching costs.

The present invention solves the above-mentioned problems of the prior art, improves the means for connecting leads to the semiconductor chip in a semiconductor device in which the semiconductor chip is mounted on a tape by tape automated bonding, and achieves low cost. Its purpose is to provide a semiconductor device.

[Means for Solving the Problems] A structure of a semiconductor device according to the present invention for solving the above problems is such that a semiconductor chip is mounted on a tape by tape automated bonding, and the semiconductor chip is mounted on a tape by tape automated bonding. In a semiconductor device in which the bump part of a lead having a bump part is connected to the upper aluminum pad by heat compression bonding via gold plating applied to the bump part, the lead is connected to the bump part by plastic processing. This is the formed plastic working lead.

More specifically, bend the tip of a lead with a plate thickness of t,
Alternatively, by squeezing, a bump portion having a height h can be formed without using the conventional method of forming a bump portion by etching (the latter connection method).

[Function] Since the bump part is formed by plastic working, the material cost and processing cost of the lead are reduced, and the yield is also improved.
A low-cost semiconductor device can be obtained.

[Example code] Hereinafter, the present invention will be explained by examples.

FIG. 1 is an enlarged side view showing the main part of a semiconductor device according to a first embodiment of the present invention (before the plastic working lead is connected), and FIG. 2 is a side view showing the plastic working lead in FIG. 1. FIG. 3 is a top view of the main part and a sectional view of the main part showing the processing state of the plastic working lead according to FIG. 2.

In the figure, the same parts are denoted by the same numbers as in FIG. 7. The IA has a bump portion 2 near its tip.
This is a deformed material obtained by forming A by plastic working (the working method will be described later). The plate thickness t of this plastic working lead IA is uniform, and the height of the bump portion 2A is the same as that of the bump portion.

The bump portion W has a convex shape, and the bump portion 2A is plated with gold (not shown) to a thickness of 1 to 2 μm.

Bump portion 2A of plastic working lead IA formed in this way
As in the past, position the bump part 2A so that it is on the aluminum pad 3 of the semiconductor chip 5, and use a heated pressing jig (not shown) to heat and press the bump part 2A onto the aluminum pad 3. As a result, the plastic working leads IA are connected to the semiconductor chip 5, and a desired semiconductor device is obtained.

A method of processing the plastic working lead IA will be explained using FIG. 3.

In FIG. 3, 6 is an upper mold in which a convex portion 6a with a height h is formed, 7 is a lower mold in which a recess 7a is formed in a depth h, and the upper mold 6 is at the lower end (from the lower mold 7). When the convex portion 6a and concave portion 7a of both types are lowered to a position separated by a distance t upward,
The bump portion 2A can be formed using the steps shown in FIG.

Upper mold configured in this way 6. Using the lower mold 7, a lead material having a thickness of t is placed on the lower mold 7 (at the position indicated by the broken line), and by lowering the upper mold 6 to the lowering end, the lead material forms the convex portions 6a, The bump portion 2A is formed by bending in the recess 7a, and the plastic working lead IA is processed.

According to the embodiment described above, it is not necessary to form protrusions on the semiconductor chip or to form leads by etching as in the conventional case (that is, the thickness of the lead material and the thickness of the plastically processed leads are different from each other). Therefore, the material cost and processing cost of the plastically processed lead IA are reduced, and a low-cost semiconductor device can be obtained.

Note that if the punching of the lead frame and the molding of the bump portion are performed at the same time, it is possible to significantly reduce costs during mass production.

Furthermore, if a large number of plastic working leads are simultaneously processed by a pair of upper and lower dies, the processing efficiency will be further improved.

Other embodiments will be described below.

FIG. 4 shows the main parts of a plastically worked lead of a semiconductor device according to a second embodiment of the present invention, and FIG.
The top view is a top view, and the figure (b) is a side view.

The plastic working lead IB is formed by forming a bump portion 2B having a bump width W and a bump height h from its tip.

This plastic working lead IB has only one bent portion of the bump portion 2B, so it is an upper die with a step.

There is an advantage that the plastic working lead IA according to FIG. 1 can be processed more easily using a lower die (not shown) than the plastic working lead IA shown in FIG. Another advantage is that even if the bump width W changes due to a change in the type of semiconductor device, the bump portion can be molded simply by shifting the positions of the upper mold and the lower mold.

FIG. 5 shows the main parts of a plastically worked lead of a semiconductor device according to a third embodiment of the present invention, and FIG. 5(a) is a top view thereof, and FIG. 5(b) is a side view thereof.

This plastically worked lead IC has its bump portion 2C formed by drawing.

This plastically processed lead IC has very little spring bag after molding the bump portion 2C, so the aluminum pad 3
The advantage is that the parallelism of the contact surfaces can be maintained very precisely.

[Effects of the Invention] As described in detail above, according to the present invention, in a semiconductor device in which a semiconductor chip is mounted on a chip by tape automated bonding, the means for connecting leads to the semiconductor chip is improved. However, there is an effect that a low-cost semiconductor device can be provided.

[Brief explanation of the drawing]

FIG. 1 is an enlarged side view showing the main part of the semiconductor device according to the first embodiment of the present invention (before the strain-forming lead is connected), and FIG. 2 is the plastic processing shown in FIG. 1. FIG. 3 is a top view of the main part of the lead, FIG. 3 is a cross-sectional view of the main part showing the processing state of the plastically processed lead according to FIG. 2, and FIG. 4 is the plastic processing of the semiconductor device according to the second embodiment of the present invention. The main parts of the lead are shown in FIG. 5(a) is a top view, FIG. 5(b) is a side view, and FIG. Figure (a) shows the main parts.
FIG. 6 is a plan view showing an example of a conventional semiconductor device in which a semiconductor chip is mounted on tape by the TAB method. FIG. 2 is an enlarged side view of the main part in the figure (before the leads are connected); LA, IB, IC...plastic processing lead, 2A, 2B,
2G...Bump portion, 3...Aluminum pad, 5...Semiconductor chip.

Claims (1)

[Claims] 1. A semiconductor chip is mounted on a tape by tape automated bonding, and the bump portion of a lead having a bump portion is attached to an aluminum pad on the semiconductor chip. In a semiconductor device that is connected by heat and pressure bonding through gold plating applied to
1. A semiconductor device characterized in that the lead is a plastic processed lead whose bump portion is formed by plastic processing. 2. The semiconductor device according to claim 1, wherein the plastic working lead has a uniform plate thickness and is convex at the bump portion.