KR0128492B1 - Method for forming a isolating layer of capacitor - Google Patents

Abstract

A method for the forming device isolation film of semiconductor devices comprises a first through ninth steps. The first step is to sequentially form a first pad oxide film and a field oxide mask film on the semiconductor substrate. The second step is to form a trench by the partial etching an exposed portion of the semiconductor substrate after a predetermined portion of the field oxide mask film and the first pad oxide film are etched. The third step is to form a second pad oxide film by a thermal oxide process inside the trench. The fourth step is to form an insulation film the selective etching ratio of which is excellent compared to the second pad oxide film. The fifth step is to expose a portion of the second pad oxide film on the bottom of the trench after a insulation film spacer is formed on the side wall of a field region defined by an isolation etch by the isotropic dry etching the insulation film. The sixth step is to remove the second pad oxide film on the bottom of the exposed trench. The seventh step is to form an epitaxial layer by the crystal growing on the semiconductor substrate exposed by removing the second pad oxide film. The eighth step is to form a field oxide film which is a device isolation layer by performing a field oxidation. The ninth step is to remove the field oxide mask film. Thereby, the process becomes simple.

Description

Device Separator Formation Method

1A to 1F are process diagrams for forming an isolation layer according to an embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

1 silicon substrate 2,6 pad oxide film

3: nitride film 4: photosensitive film

5: trench 7: SRO film

7 ': spacer 8: silicon epitaxial layer

9: field oxide film

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a device isolation layer in a semiconductor manufacturing process, and more particularly, to a method of forming a device isolation layer using SEG (Selective Epitaxy Growth) technology.

The process of forming a device isolation film using SEG technology is a technique of growing a substrate after exposing the substrate in the insulating film, which is very good silicon single crystal without plasma damage during plasma etching for trench formation. The process is very difficult to prepare the noodles.

The present invention, which is drawn out to solve the above problems, is to provide a device isolation film forming method for forming a device isolation film by the SEG process using a thermal oxide film and an insulating film excellent in etching selectivity.

In order to achieve the above object, the present invention comprises the steps of sequentially forming a first pad oxide film field oxide mask film on a semiconductor substrate; Etching the field oxide mask layer and the first pad oxide layer at a predetermined portion and forming a trench by partially etching the semiconductor substrate: forming a second pad oxide layer in the trench by a thermal oxidation process; Forming an insulating film having an excellent selective etching ratio with respect to the second pad oxide film on an entire structure surface; Anisotropic dry etching the insulating film to form a spacer on a sidewall of a field region defined by isolation etching and exposing a portion of the second pad oxide film at the bottom of the trench; Raising a second pad oxide layer of the exposed trench bottom; Crystal growing a semiconductor substrate exposed by removing the second pad oxide film to form an epitaxial layer; Performing field oxidation to form a field oxide film as a device isolation film; And removing the field oxide mask film.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings 1A to 1F.

First, FIG. 1A shows that the pad oxide film 2 is formed on the silicon substrate 1 by 50 to 500 microseconds, and the nitride film 3 is formed on the pad oxide film 2 to 100 to 3000 microseconds. Pattern (4).

Subsequently, as illustrated in FIG. 1B, the nitride film 3 and the pad oxide film 2 are sequentially etched using the photoresist film 4 as an etch barrier, and the silicon substrate 1 is etched at 2000 to 7000 Å to form the trench 5. After the formation of the photoresist film 4 is removed.

Subsequently, as shown in FIG. 1C, the second pad oxide film 6 is formed in the trench 5 at about 50 to 1000 Pa at 800 to 1200 ° C., and the SRO (silicon rich oxide) film 7 is formed on the entire structure. Deposit. Here, the SRO film is a material having a strong dielectric property and has an intermediate property between silicon and an oxide film, and is an insulating film that can control the etching ratio during wet etching.

Subsequently, as shown in FIG. 1D, the SRO film 7 is anisotropically etched by a dry etching method having an excellent etching selectivity with the second pad oxide film 6, which is a thermal oxide film, and the spacer 7 is formed on the sidewall of the field region defined by isolation etching. Form ').

Subsequently, as shown in FIG. 1E, the second pad oxide film 6 exposed at the bottom of the trench 5 is removed by HF wet cleaning or HF vapor cleaning to expose the silicon substrate 1, and then the silicon epi The tactile layer 8 is formed.

Subsequently, when the field oxidation is performed at 300 to 3000 Pa at 950 to 1200 DEG C and the nitride film 3 is removed as in Fig. 1f, only the final field oxide film 9 remains.

In the present invention, the SRO film reduces the shape of the beak formed as the edges of the field oxide film are elongated, and instead of the SRO material, a material such as a high temperature oxide film (HTO) and an oxynitride having excellent etching selectivity may be used. In addition, a polysilicon film is further formed below the nitride film 3 to serve as a stress buffer during field oxidation, thereby obtaining a field oxide film having defects of good profile and low density.

As described above, the present invention as described above can secure the crystalline front, which was the most problematic in the SEG technology, can be applied as a next-generation device isolation method, and the process is not necessary during the planarization process.

Claims (3)

A device isolation film forming method of a semiconductor device; Sequentially forming a first pad oxide film and a field oxide mask film on a semiconductor substrate; Etching the field oxide mask layer and the first pad oxide layer at a predetermined portion, and forming a trench by partially etching the exposed semiconductor substrate; Forming a second pad oxide layer in the trench by a thermal oxidation process; Forming an insulating film having an excellent selective etching ratio with respect to the second pad oxide film on an entire structure surface; Anisotropic dry etching the insulating film to form an insulating film spacer on a sidewall of the field region defined by isolation etching, thereby exposing a portion of the second pad oxide film on the bottom of the trench; Removing the second pad oxide layer on the bottom of the exposed trench; Crystal growing a semiconductor substrate exposed by removing the second pad oxide film to form an epitaxial layer; Performing field oxidation to form a field oxide film as a device isolation film; And removing the field oxide mask film. The method of claim 1, wherein the field oxide mask film is a double structure film of a nitride film or a polysilicon film and a nitride film. The method of claim 1, wherein the insulating layer is any one of a silicon rich oxide (SRO), a high temperature oxide layer (HTO), and an oxynitride layer.