KR19990003538A - Manufacturing method of semiconductor device - Google Patents

Abstract

The present invention relates to a method for manufacturing a semiconductor device, and more particularly, to a method for producing a field oxide film having a fine width trench structure.

According to an embodiment of the present invention, a mask pattern is formed on a semiconductor substrate at predetermined intervals, spacers are formed on both sides of the mask pattern, and the mask pattern and the spacer are used as a mask to etch the exposed semi-conductive substrate. Forming a trench and embedding an insulator in the trench.

Description

Manufacturing method of semiconductor device

The present invention relates to a method for manufacturing a semiconductor device, and more particularly, to a method for producing a field oxide film having a fine width trench structure.

In addition to the progress of semiconductor technology, the speed and integration of semiconductor devices are increasing, and the necessity of miniaturization of patterns is increasing, and the size of patterns is also required to be highly precise.

This also applies to device isolation regions that occupy a wide area in semiconductor devices.

Accordingly, a field oxide film having a fine trench structure is used instead of a field oxide film by LOCOS technology having a high topology and occupying a large area.

The field oxide film of such a conventional trench structure forms a mask pattern on a semiconductor substrate with a width of an exposure limit, and forms a trench by etching the semiconductor substrate in the form of this mask pattern. Subsequently, after removing the mask pattern, oxide is embedded in the trench to form a field oxide film.

However, even when the trench field oxide film is formed by the above-described prior art, the field oxide film still occupies a large area even in highly integrated semiconductor devices.

For this reason, a field oxide film having a fine width is required while requiring a sufficiently high insulating property as a field oxide film of a highly integrated semiconductor device.

Accordingly, an object of the present invention is to provide a method for manufacturing a semiconductor device in which the width of a trench field oxide film is formed below an exposure limit, and thus can be applied to a highly integrated semiconductor device. .

1A to 1E are cross-sectional views of a semiconductor device for describing an embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

1 semiconductor substrate 2 mask pattern

3a: spacer 4: trench

5: oxide

In order to achieve the above object of the present invention, the present invention, forming a mask pattern at a predetermined interval on the semiconductor substrate, forming a spacer on both sides of the mask pattern, masking the mask pattern and the spacer And etching the exposed semiconductor substrate to form trenches and embedding insulators in the trenches.

According to the present invention, in the process of forming a mask for forming a trench, a gap between the masks is formed to a width of an exposure limit, spacers are formed on both side walls of the mask, and then a trench is formed using the mask and the spacers. do. Accordingly, the width of the trench is formed below the exposure limit and can be applied as a field oxide film of a highly integrated semiconductor device.

EXAMPLE

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1A to 1E are cross-sectional views illustrating a semiconductor device for describing an embodiment of the present invention.

First, referring to FIG. 1A, a first thin film for a mask is formed on a semiconductor substrate 1, for example, a silicon substrate having a predetermined well (not shown). A film having an etch rate different from that of the semiconductor substrate 1 is formed, for example, a silicon oxide film, a silicon nitride film and a photoresist film. Thereafter, the first thin film is patterned to expose the device isolation region, thereby forming a mask pattern 2. In this case, when the first thin film is a silicon oxide film or a silicon nitride film, a resist pattern is formed on the film by a photolithography process, and then a predetermined portion is etched to form the pattern 2. When the first thin film is a photoresist film, the mask thin film itself is partially exposed and developed to form a mask pattern 2. At this time, the width a between the exposed mask patterns 2 is the current exposure. It is the exposure limit width which can be formed as equipment.

Subsequently, as shown in FIG. 1B, a predetermined second thin film 3 is formed on the semiconductor substrate 1 on which the mask pattern 2 is formed to have a predetermined thickness. The second thin film 3 is a film different in etching rate from the semiconductor substrate 1 similarly to the first thin film.

Thereafter, the second thin film 3 is etched entirely so that the surface of the mask pattern 2 is exposed, and as shown in FIG. 1C, spacers 3a are formed on both sides of the masco pattern 2. At this time, the spacer pattern 3a having the predetermined width b is formed on both sidewalls of the mask pattern 2, and the width c of the substrate exposed is substantially the width of the non-lateral spacers in the width a between the mask patterns. The value is subtracted by (2 × B). As a result, a width below the exposure limit is exposed.

Then, as shown in FIG. 1D, the exposed semiconductor substrate 1 is etched to a predetermined depth using the mask pattern 2 and the spacer 3a as a mask to form a trench 4. At this time, the semiconductor substrate 1 is preferably etched by an anisotropic dry etching process so that side spread etching does not occur.

Then, referring to FIG. Le, the mask pattern 2 and the spacer 3a formed on the semiconductor substrate 1 are removed in a known manner, and the oxide film 5 is formed so that the semiconductor substrate 1 is sufficiently buried. . Next, the oxide film 5 is removed so that the surface of the semiconductor substrate 1 is exposed, and the oxide film 5 is embedded only in the trench 4. At this time, an anisotropic etch back or chemical mechanical polishing is used as a method of removing the oxide film. In addition, when the mask pattern 2 and the spacer 3a are formed of a silicon oxide film, the mask pattern 2 and the spacer 3a may be removed at the same time as the oxide film removal process for embedding the oxide film 5 without a separate removal process. Further, even if the mask pattern 2 and the spacer 3a are not silicon oxide films, they can be removed at the same time in removing the oxide film for embedding.

The present invention described above is not limited to this embodiment.

In the present invention, a trench having a fine width has been described as an example. However, the present invention can be applied to a process requiring an interval below the other exposure limit.

As described in detail above, according to the present invention, in the process of forming the mask for forming the trench, the gap between the masks is formed with the width of the exposure limit, and spacers are formed on both side walls of the mask, and then the mask and the spacers are formed. To form a trench. Accordingly, the width of the trench is formed below the exposure limit and can be applied as a field oxide film of a highly integrated semiconductor device.

In addition, this invention can be implemented in various changes within the range which does not deviate from the summary.

Claims (7)

Forming a mask pattern on the semiconductor substrate at predetermined intervals, forming spacers on both sides of the mask pattern, etching the exposed semiconductor substrate using the mask pattern and the spacer as a mask, and forming a trench And filling an insulator in the trench. The method of claim 1, wherein both the mask pattern and the spacer are made of a material having a different etching rate from a material forming a semiconductor substrate. The method of claim 2, wherein the material forming the mask pattern and the spacer is a silicon oxide film, a silicon nitride film, or a photoresist film. The method of claim 1, further comprising removing the mask pattern and the spacer between the step of forming the trench and the step of filling the insulator in the trench. 2. The method of claim 1, wherein embedding an insulator in the trench comprises depositing a nitride such that the resulting substrate is sufficiently embedded and removing the insulator to expose the surface of the semiconductor substrate. A method of manufacturing a semiconductor device. The method of claim 5, wherein in the removing of the insulator, the mask pattern and the spacer are simultaneously removed. The method of claim 5, wherein the removing of the insulator is performed by using an anisotropic etch back method or a chemical mechanical polishing method.