JPS6285435A - Semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the shape of electrode wirings from damaging and to simultaneously prevent a passivation film from cracking by forming the thickness of the passivation film 1.8mum or larger, thereby protecting the electrode wirings against the stress of a molding material. CONSTITUTION:The thickness of a passivation film 3 is set to 1.8mum or larger. For example, the film 3 is formed of a nitride film, the thickness is set to 1.0mum of the conventional value or lower to 0.8mum to eliminate the influence of the stress from a molding material 7 to the wirings 4 of electrodes. In other words, since the thickness of the film 3 is 1.8mum or larger, the wirings 4 are protected against the stress of the material 7, and the film 3 is prevented from cracking.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a semiconductor device, and particularly to a semiconductor integrated circuit <I
This relates to improvements to the passivation film used in C>.

[Prior Art] The cross-sectional structure of a conventional IC chip will be explained with reference to FIG. 2. An insulating film 2 is formed on a silicon substrate 1 containing a semiconductor element. Electrode wiring 4 is selectively formed.

Further, a passivation film 3 made of a thin film having a thickness of 1 μm or less is formed on the insulation 1112 and the electrode wiring 4.

The purpose of this passivation film is to eliminate external influences such as moisture absorption on the semiconductor element, and to provide electrical insulation between each element.

FIG. 3 is a sectional view showing the structure of the IC after molding. In the figure, a silicon substrate 1 is soldered onto a lead frame 8 using a soft solder 9. This soft solder 9 is for relieving stress generated on the silicon substrate 1.

After the passivation film 3 is formed, the passivation film 3 on the electrode wiring 4 is etched, and the electrode wiring 4 and the lead wire 5 are connected with a wire bond 6, and the lead frame 8, soft solder 9, silicon substrate 1, and insulating film are connected. 2, the electrode wiring 4, the passivation film 3, the wire bond 6, and a part of the lead wire 5 are sealed with a molding material 7.

This molding material 7 is for preventing the IC chip from absorbing moisture or receiving mechanical damage from the outside.

[Problems to be Solved by the Invention] By the way, the thickness of the conventional passivation film 3 is approximately 7500 mm1, as mentioned above. Therefore, after sealing with the molding material 7, stress from the molding material 7 is applied to the passivation film 3 and the electrode arrangement i! When added to 4 and 4, these are −
The shape of the electrode wiring 4 is destroyed by sliding together, and at the same time as this shape destruction, the passivation film 3 has a fourth
As shown in the figure, cracks 10 were generated, causing problems such as deterioration of the moisture resistance of the IC.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to obtain a semiconductor device that can prevent the destruction of the shape of electrode wiring and at the same time prevent the generation of cracks in the passivation film.

Means for Solving Problems] A semiconductor device according to the present invention has a passivation film having a thickness of 1.8 μm or more.

[Function] In this invention, the thickness of the passivation film is 1.
Since it is 8 μ- or more, the electrode wiring is protected from the stress of the molding material, and the passivation film is prevented from cracking.

[Example] As a means to solve the above problems, (1) the material of the molding material 7 is changed to reduce stress on the IC chip; (2) Increasing the strength of the passivation film 3 against stress from the molding material 7. (2) Increasing the hardness of the material of the electrode wiring 4, etc., but this invention adopts the method (2). That is, in the embodiment of the present invention, the passivation film 3 is a nitride film, and its thickness is increased from the conventional 1.0 μm or less to 1.8 μm to prevent stress from the molding material 7 from affecting the electrode wiring 4. Excluded.

Hereinafter, an experimental example leading to the present invention will be explained using FIG. 1. Figure 1 shows the relationship between the film thickness of the plasma CVD nitride film and its failure rate when the film thickness of the plasma CVD nitride film of semiconductor devices is varied and the semiconductor devices are subjected to 210 temperature cycles. These are the experimental results shown. In this experimental example, aluminum is used as the material of the electrode wiring 4, and plasma CVD is used as the passivation film 3.
A nitride film was formed using a D (chemical vapor deposition) apparatus.

The thickness of the plasma CVD nitride film is 0.70m.
, 1.0!1m, 1.2t1m, 1.5μm, 1°8μ
The crack occurrence rate of the plasma CVD nitride film under each condition was investigated by subjecting the semiconductor device having each of these films to 210 m degree cycles. From this experimental result, it was found that a plasma CVD nitride film with a thickness of 1.8 μm or more is effective in eliminating the influence of stress from the molding material 7 on the electrode wiring 4 and preventing cracks in the plasma CVD nitride film. It turned out to be the case.

In the above embodiments, the case where the passivation film is a plasma CVD nitride film has been described, but instead of this film, a plasma CVD nitride film or a plasma CVD nitride film may be used.
An oxynitride film may also be used, and the same effects as in the above embodiments can be achieved in these cases as well.

In addition, in the above example, improvement of the thickness of the passivation film was explained as a means to solve the problem. Recruitment is also effective in solving problems.

[Effects of the Invention] As described above, according to the present invention, the thickness of the passivation film is increased from the conventional thickness of 1.0 μm or less to 1.8 μm or more, thereby protecting the electrode wiring from the stress of the molding material and preventing its shape from being destroyed. Accordingly, it is possible to obtain a semiconductor device that can prevent the occurrence of cracks in the passivation film.

[Brief explanation of drawings]

Figure 1 shows the relationship between the film thickness of the plasma CVD nitride film and its failure rate when the film thickness of the plasma CVD nitride film of semiconductor devices is varied and the semiconductor devices are subjected to 210 temperature cycles. These are the experimental results shown. FIG. 2 is a cross-sectional view showing the structure of the IC chip. FIG. 3 is a sectional view showing the structure of the IC after molding. FIG. 4 is a diagram showing how cracks occur in a passivation film due to stress from a molding material in a conventional semiconductor device. In the figure, 1 is a silicon substrate, 2 is an insulating film, 3 is a passivation film, 4 is an electrode wiring, 5 is a lead wire, 6 is a wire bond, 7 is a molding material, 8 is a lead frame, 9
10 is soft solder and 10 is crack. It should be noted that the arrows in each figure indicate the same or corresponding parts.

Claims (6)

[Claims] (1) A substrate including a semiconductor element, an insulating film formed on the substrate, an electrode wiring selectively formed on the insulating film, and a passivation formed on the insulating film and the electrode wiring. A semiconductor device comprising: a molding material for sealing the substrate, the insulating film, the electrode wiring, and the passivation film, wherein the passivation film has a thickness of 1.8 μm or more. semiconductor device. (2) The semiconductor device according to claim 1, wherein the substrate is a silicon substrate. (3) The semiconductor device according to claim 1, wherein the passivation film is a plasma CVD nitride film. (4) The passivation film is plasma CVD PS
The semiconductor device according to claim 1, which is a G film. (5) The semiconductor device according to claim 1, wherein the passivation film is a plasma oxynitride film. (6) The semiconductor device according to claim 1, wherein the electrode wiring is made of aluminum.