JPH0689893A - Semiconductor device - Google Patents

Abstract

PURPOSE:To reduce an internal stress of a semiconductor device and sufficiently increase a film thickness of an interlayer insulation film until the flatness degree becomes high by a method wherein two kinds of insulation matter in which internal stresses are different in the directions of a pulling stress and a compressing stress applied are used as an insulation film. CONSTITUTION:In this semiconductor device, a semiconductor element is formed inside and a first layer electrode 12 is formed on a silicon substrate 11 coated with an insulation film (for example, SiO2 film) having a connecting opening on the surface, and a plasma nitrided film 13 grows thereon. Also, a SiO2 film 15 grows on the plasma nitrided film 13 by a CVD method to form an interlayer insulation film, and a second layer electrode 14 is formed thereon which is electrically connected with the first layer electrode 12 through a contact hole formed by etching a predetermined location of the interlayer insulation film 15. At this time, an internal stress of the plasma nitrided film 13 is used as a compressing stress and an internal stress of the SiO2 film 15 is used as a pulling stress, and the internal stresses of the two films 13, 15 are cancelled mutually to reduce the internal stress.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a semiconductor device, and more particularly to the structure of an interlayer insulating film.

[0002]

2. Description of the Related Art In a semiconductor device, two or more layers of electrodes are formed in order to reduce the area required for wiring and realize high integration and high density. A silicon oxide film (hereinafter referred to as a SiO ₂ film) or the like is formed between the electrodes of each layer and is insulated and separated. The interlayer insulating film is required to have the following characteristics.

1. Good step coverage.

2. Good adhesion with the electrode.

3. Good crack resistance.

4. High pressure resistance. Meet the above requirements, It can be formed at low temperature.

2. The role of preventing the invasion of impurities such as water and sodium from the outside is remarkable. A silicon nitride film (hereinafter abbreviated as plasma nitride film) formed by the plasma CVD method, which has the feature that is mainly used as an interlayer insulating film.

FIG. 3 shows a typical example in which a plasma nitride film is used as an interlayer insulating film. A first layer electrode 2 is formed on a silicon substrate 1 whose surface is covered with a silicon oxide film and a semiconductor element is formed inside, and a plasma nitride film 3 and a second layer electrode 4 are formed on this. There is. The first layer electrode 2 and the second layer electrode 4 are electrically connected by a through hole formed by etching the plasma nitride film 3.

[0009]

In recent years, the integration of semiconductor devices has advanced, the pattern width has become narrower, and the ratio between the pattern width and the film thickness (hereinafter referred to as the aspect ratio) has increased. Therefore, it has become necessary to increase the thickness of the plasma nitride film so as to improve the flatness of the interlayer insulating film. However, when the thickness of the plasma nitride film is increased, the internal stress is increased, which causes a crack in the plasma nitride film, which facilitates the intrusion of impurities from the outside.

[0010]

According to the present invention, as an interlayer insulating film, two kinds of insulators having different internal stresses in directions in which tensile stress and compressive stress are applied are used, and a semiconductor device using insulating films laminated on each other is used. To get

[0011]

The present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of an electrode portion of a semiconductor device showing an embodiment of the present invention. An insulating film (for example, SiO ₂₎ having a semiconductor element formed inside and a surface having an opening for connection is formed.
0.5 μm thick on a silicon substrate 11 covered with a film)
1st layer electrode 12 of is formed. On top of that 1.
A plasma nitride film 13 having a thickness of 0 μm is grown, and a SiO ₂ film 1 having a thickness of 1.0 μm and formed by a normal pressure CVD method is further formed thereon.
5 is grown to form an interlayer insulating film. The first layer electrode 12 and the second layer electrode 14 are electrically connected to each other at a contact hole portion formed by etching a predetermined place of the interlayer insulating film.

Here, the internal stress of the plasma nitride film 3 is a compressive pressure and its magnitude is 4 × 10 ⁹ dyn / cm ² . On the other hand, the internal stress of the SiO ₂ film 5 is tensile stress and its magnitude is 6 to 8 × 10 ⁸ dyn / cm ² , and the internal stresses of the two films are almost canceled.

A similar effect is obtained by using a phosphosilicate glass film (Phospho-Silicate) instead of the SiO ₂ film.
It can also be obtained by using Glass).

FIG. 2 is a sectional view of an electrode portion of a semiconductor device showing another embodiment of the present invention. A semiconductor element is formed inside, and the surface is covered with a SiO ₂ film or the like except for the electrode connection portion. The thickness is 2.0 μm and the electrode width is 1.0 μm on the silicon substrate 21.
A first layer electrode 22 having a μm aspect ratio of 2 is formed. A plasma nitride film 23 having a thickness of 1.5 to 2.0 μm is formed thereon. 1.5-2.0 on top of it
A SiO ₂ film 25 having a thickness of 0.5 μm and a plasma nitride film 26 having a thickness of 0.5 to 2.0 μm are formed to form a three-layer interlayer insulating film. The first layer electrode 22 and the second layer electrode 24 are electrically connected to each other through a contact hole formed by etching a predetermined place of the interlayer insulating film.

Here, the internal stress of the plasma nitride film is a compressive stress, and its magnitude is 4 × 10 ⁹ dyn / cm ² . On the other hand, the internal stress of the SiO ₂ film is tensile stress and its magnitude is 6 to 8 × 10 ⁸ dyn / cm ² . Therefore, the internal stress of these two films is almost canceled.

Further, a phosphorus silicate glass film (hereinafter P
Since a SG film) also has a tensile stress, the same effect can be obtained by using a PSG film instead of the SiO ₂ film.

[0018]

As described above, according to the present invention, since the SiO ₂ film or the PSG film having a different internal stress from the plasma nitride film is grown on the plasma nitride film layer, the internal stress can be reduced and the flatness can be improved. Until then, the thickness of the interlayer insulating film can be increased sufficiently.

[Brief description of drawings]

FIG. 1 is a sectional view of an electrode portion of a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a sectional view of an electrode portion of a semiconductor device according to another embodiment of the present invention.

FIG. 3 is a sectional view of an electrode portion of a conventional semiconductor device.

[Explanation of symbols]

1,11,21 Silicon substrate 2,12,22 First layer electrode 3,13,23,26 Plasma nitride film 4,14,24 Second layer electrode 5,15,25 SiO ₂ film

Claims (4)

[Claims] 1. A semiconductor device characterized in that, as the insulating film, two kinds of insulators having different internal stresses in different directions in which tensile stress and compressive stress are applied are used. 2. The two different types of insulators are plasma nitride and silicon oxide.
Described semiconductor device 3. The semiconductor device according to claim 1, wherein the insulating film is composed of three or more insulating films. 4. The semiconductor device according to claim 3, wherein the three or more insulating films are laminated such that one of the two different kinds of insulators is sandwiched by the other.