JPH02257657A - Semiconductor device - Google Patents

Abstract

PURPOSE:To avoid that a crack is produced and to enhance moistureproofness by a method wherein a plane shape at individual corner parts of a cover film which is not water-absorbent is formed in a polygonal shape or a nearly arc shape. CONSTITUTION:A wiring layer is formed on a semiconductor chip 1; a cover film (PSG film, SiN film, SiON film or SiO2 film) 2 which is not water-absorbent is formed on an upper layer of the wiring layer by using a mask in a last process to form the semiconductor chip 1. A shape of this mask is set to a shape in which individual corner parts of the semiconductor chip 1 have been cut off, i.e., a polygonal shape which has two angles A, B at each corner. Accordingly, a stress by a thermal stress is dispersed to two points at the two angles A, B at each corner. Thereby, it is possible to avoid that the stress is concentrated at corner parts of the cover film 2, to prevent a crack from being produced and to enhance a moistureproofness.

Description

[Detailed Description of the Invention] [Summary] The present invention aims to improve moisture resistance of semiconductor devices by devising the planar shape of the corner portions of the cover film to disperse stress and prevent cracks from occurring at the corner portions. In a semiconductor device having a structure in which a non-water-absorbing cover film is provided on the upper layer of a wiring layer of a semiconductor chip having a substantially rectangular planar shape, the planar shape of each corner portion of the cover film is as follows:
The structure is characterized by being formed into a polygonal shape or a substantially arcuate shape.

[Industrial application field]

The present invention relates to a semiconductor device, and particularly to a semiconductor device in which a semiconductor chip is provided with a cover film for ensuring moisture resistance.

Generally, semiconductor chips are sealed using plastic gauges, etc., but during the sealing process, atmospheric gas
If it contains moisture, its properties may change due to the influence of this moisture.

Therefore, a non-water-absorbing cover film is provided on the semiconductor chip in advance.

[Conventional technology]

As a conventional semiconductor device of this type, one is known in which a non-water-absorbing cover V (for example, a PSG film) is provided on the wiring layer of a semiconductor chip, either directly or through another protective film. According to such a configuration, even if the atmospheric gas during the sealing process contains moisture, this moisture can be cut off by the cover film, and the moisture resistance of the semiconductor chip can be ensured.

C Problems to be Solved by the Invention] However, in such conventional semiconductor devices, the planar shape of the cover film is similar to the planar shape of the semiconductor chip (generally rectangular), as shown in FIG. Therefore, there was a problem that, for example, cracks may occur in the cover film (particularly at the corner portions) during heat treatment during attaching the die or sealing.

In other words, the cause of cracks is that stress due to thermal stress is applied to the cover film due to the difference in thermal expansion coefficient between the cover film and other materials that come into contact with the cover film (pancage material and various materials of semiconductor chips). In particular, the main cause of the above problem is that the stress tends to be concentrated at the acute angle portions, ie, corner portions, of the cover film. By the way, the cover film is P
When used as a G film, the thermal expansion coefficient of this PSGO is 9X10
In contrast, the thermal expansion coefficient of the sealing material, such as resin, in contact with the PSG is 2X10-', and the thermal expansion coefficient of silicon (St) is 4X10-'.

The present invention was made in view of these problems, and
The planar shape of the corners of the cover film is devised to disperse stress, prevent cracks from occurring at the corners, and improve moisture resistance.
The purpose is to achieve this goal.

[Means to solve the problem]

In order to achieve the second object, a semiconductor device according to the present invention has a structure in which a non-water-absorbing cover film is provided on an upper layer of a wiring layer of a semiconductor chip having a substantially rectangular planar shape. A feature is that each corner portion of the cover film has a planar shape of a polygon or a substantially arc shape.

[Effect]

In the present invention, stress due to thermal stress applied to the cover film is dispersed according to the planar shape of the corner portion of the cover film. Therefore, generation of cracks is avoided and moisture resistance is improved.

〔Example〕

Hereinafter, the present invention will be explained based on the drawings.

FIG. 1.2 is a diagram showing a first embodiment of a semiconductor device according to the present invention.

In FIG. 1, 1 is a semiconductor chip, and a wiring layer (not shown) is formed on the semiconductor chip 1. In addition,
A protective film made of, for example, a plasma nitride film, another film, or an electrode may be provided on the wiring layer. 2 is a non-water absorbing cover film (for example, PSG film, S
iN film, 5iON film, or Sin film), and the cover film 2 is, for example, a JaF film in the process of manufacturing the semiconductor chip 1.
& is formed using a mask. Here, the mask has a shape shown by the solid line in FIG. That is, the second
In the figure, the broken line is the outline of the planar shape of the semiconductor chip 1, and the mask shape (that is, the planar shape of the cover H2) is the shape obtained by cutting off each corner of the semiconductor chip 1 (specifically, each corner This corresponds to a polygonal shape with two angles A and B).

According to such a configuration, stress due to thermal stress is distributed to two points, ie, two corners A and B, for each corner of the cover film 2. Therefore, cover IF:! 2. Stress concentration at the corner part can be avoided, cracks can be prevented,
Moisture resistance can be improved.

Note that the planar shape of the corner portion of the cover film 2 is not limited to that shown in the above embodiment. In short, any planar shape is sufficient as long as it is suitable for dispersing stress. For example, as shown in FIG. 3, which shows a second embodiment of the semiconductor device according to the present invention, the planar shape of each corner portion of the cover film may be Polygonal shape having four corners a to d (may be a polygonal shape with four or more corners)
Alternatively, as shown in FIG. 4, which shows a third embodiment of the semiconductor device according to the present invention, each corner of the cover film may have a planar shape of an arc (here, an arc is a shape other than a straight line). It refers to a part of the circumference of a circle drawn by a curved line, and the curvature of the arc does not necessarily have to be constant).

That is, in the second embodiment, the stress distribution points for each corner can be set to four points of a % d, so 1) ↑
This embodiment is more preferable than the first embodiment, and since no corners are formed in the third embodiment, it is most preferable in terms of stress distribution.

〔Effect of the invention〕

According to the present invention, since the planar shape of the corner portion of the cover film is devised to disperse stress, it is possible to prevent cranks from occurring at the corner portion, and it is possible to improve moisture resistance.

FIG. 1 is a perspective view of a semiconductor chip provided with the cover film, FIG. 2 is a diagram illustrating the planar shape of the cover film, and FIG. 3 is a cover showing a second embodiment of the semiconductor device according to the present invention. FIG. 4 is a diagram illustrating the planar shape of the film, FIG. 4 is a diagram illustrating the planar shape of the cover film showing the third embodiment of the semiconductor device according to the present invention, and FIG. FIG. 3 is an explanatory diagram of cracks that occur at the corner portions of FIG.

1... Semiconductor chip, 2...Cover membrane.

[Brief explanation of drawings]

1.2 is a diagram showing a first embodiment of the semiconductor device according to the present invention. FIG. 1 is a perspective view of a semiconductor chip provided with a cover film of the first embodiment. FIG. 3 is a perspective view of a semiconductor chip provided with a cover film of the first embodiment. Figure 92 for explaining the planar shape of the film; Figure Wi4 for explaining the planar shape of the cover film of the third embodiment.

Claims (1)

[Scope of Claims] In a semiconductor device having a structure in which a non-water-absorbing cover film is provided on an upper layer of a wiring layer of a semiconductor chip having a substantially rectangular planar shape, the planar shape of each corner portion of the cover film is , a semiconductor device characterized in that it is formed in a polygonal shape or a substantially arc shape.