JPH05275420A - Manufacture of silicon oxide film of semiconductor device - Google Patents

Abstract

PURPOSE:To provide the manufacture of SiO2 film of a semiconductor device using a novel liquid raw material, in which manufacture the SiO2 film can be formed at a temperature lower than that in the case of tetraethoxysilane and the film is excellent in difference-in-level covering properties, flattening properties, etc., and also excellent in qualities such as compactness, crack resistance and insulating properties. CONSTITUTION:When SiO2 of a semiconductor device is manufactured by CVD method, any of tetratertiarybutoxysilane, tetrasecondarybutoxysilane, tetratertiaryamyloxysilane, etc., is used as novel liquid raw material.

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 silicon oxide film of a semiconductor device, in which a SiO ₂ film is formed by a CVD method using a novel liquid raw material.

[0002]

_2. Description of the Related Art Conventionally, SiH ₄ gas raw material has been used as a SiO ₂ CVD film forming material. However, the pattern size used for integrated circuits has been becoming finer year by year with the increase in the density of circuit patterns, and is now in the submicron era.

In addition, with the miniaturization and high integration of LSI,
The area occupied by the wiring in the chip is increasing, and the multilayering of the wiring is progressing more and more. Further, in the future multi-layer wiring, the aspect ratio of the wiring becomes large because it is necessary to keep the wiring resistance small, and as a result, the unevenness of the substrate surface becomes more and more severe. Therefore, planarization of an insulating film such as SiO ₂ is an indispensable technique.

The conventional CVD process using a SiH ₄ gas source cannot flatten the steps and irregularities on the substrate. Further, in this CVD process, voids are formed between narrow electrodes or in the trench of the gate, and the film characteristics are significantly deteriorated. Furthermore, SiH ₄ is a self-igniting and extremely dangerous raw material.

In order to overcome the above drawbacks, recently, a CVD method using tetraethoxysilane Si (OC ₂ H ₅ ) ₄ which is a liquid raw material in place of SiH ₄ has been put into practical use and has become popular. It was

This vaporizes tetraethoxysilane,
It is introduced into the CVD reaction chamber. The film grown by the CVD method using tetraethoxysilane is excellent in step coverage and flatness, and tetraethoxysilane is not a self-igniting substance and is a very safe raw material in the manufacturing process of semiconductor devices. .. Further, as a characteristic of the flattening CVD film, a void-free flattening film can be achieved by reflow processing even in a high-density pattern portion.

However, C using tetraethoxysilane
The film grown by the VD method has its denseness, crack resistance,
There is still a problem in film quality such as insulation, and substrate heating at 600 to 700 ° C. is required to form a film so as to reduce this problem.

Therefore, when the silicon oxide film is formed on the aluminum wiring by the CVD method using tetraethoxysilane, there is a drawback that the aluminum wiring is significantly deteriorated. Therefore, a CVD liquid raw material that does not require high-temperature substrate heating and can form a silicon oxide film at a lower temperature than tetraethoxysilane has been desired.

[0009]

DISCLOSURE OF THE INVENTION The inventors of the present invention can form a SiO ₂ film at a lower temperature than tetraethoxysilane, and are excellent in step coverage and flatness.
A patent application was previously filed for a method of manufacturing a SiO ₂ film of a semiconductor device using a novel liquid raw material having excellent film properties such as crack resistance and insulation (Japanese Patent Application No. Hei 2-188322). The present invention is based on the discovery of a new liquid raw material capable of forming a silicon oxide film at a lower temperature than tetraethoxysilane as a result of further research.

[0010]

According to the present invention, tetra-tert-butoxysilane t-Si (OC) is used as a novel liquid raw material when SiO ₂ of a semiconductor device is manufactured by a CVD method.
₄ H ₉ ) ₄ , Tetrasecondary butoxysilane sec
Any one of —Si (OC ₄ H ₉ ) ₄ and tetra-tertiary amyloxysilane Si [OC (CH ₃ ) ₂ C ₂ H ₅ ] ₄ is used.

According to the present invention, the final thermal decomposition temperature of the metal alcoholate is determined by the side chain which is the most difficult to decompose among the side chains attached to the metal. Taking Si as an example of the metal, the methoxy group is 700 ° C. and the ethoxy group is 550 ° C. Propoxy groups 480
This is because of the result of research by pyrolysis gas chromatography that the final decomposition temperature becomes lower as the number of carbon atoms increases, such as ℃, butoxy group 450 ° C.

Further, SiO formed by using the raw material or the like.
No. ₂ is less likely to retain organic components, and the film quality such as denseness, crack resistance, and insulation is extremely excellent. Further, these CVD raw materials are extremely safe raw materials in the manufacturing process of the semiconductor device like the tetraethoxysilane.

[0013]

Example 1 A Si substrate was placed in a plasma CVD apparatus and the substrate was heated to 350 ° C. Tetratert-butoxysilane was bubbled with a He carrier gas at 25 ° C., introduced into a plasma CVD apparatus, mixed with oxygen in the apparatus, and a SO ₂ film was formed on a Si substrate by plasma.

As a result of comparing the hardnesses of this film and the plasma CVD film using tetraethoxysilane using a hardness meter, the film according to the present invention has a higher hardness and is a sufficiently dense film. I understood.

[0015]

Example 2 A Si substrate was placed in a plasma CVD apparatus and the substrate was heated to 350 ° C. Tetratert-amyloxysilane was bubbled with a He carrier gas at 25 ° C., introduced into a plasma CVD apparatus, mixed with oxygen in the apparatus, and a SiO ₂ film was formed on a Si substrate by plasma.

As a result of comparing the hardness of this film and the plasma CVD film using tetraethoxysilane using a hardness meter, the film according to the present invention has a higher hardness and is a sufficiently dense film. I understood.

[0017]

According to the present invention, a SiO ₂ film can be formed at a temperature lower than that of tetraethoxysilane, and the film has excellent step coverage and flatness, and has hardness, compactness and crack resistance. The film quality such as is also very excellent. Further, there is a feature that the safety is extremely high in the manufacturing process of the semiconductor device.

Claims (1)

[Claims] 1. When a SiO ₂ film of a semiconductor device is formed by a CVD method using a liquid raw material, the liquid raw material is selected from tetratertiary butoxysilane, tetrasecondary butoxysilane, tetratertiary amyloxysilane and the like. A method for manufacturing a silicon oxide film of a semiconductor device, which is characterized by being used.