KR19990055761A - Device Separating Method of Semiconductor Device - Google Patents

Abstract

The present invention relates to a method of forming a device isolation film of a semiconductor device, and to forming a groove by etching a predetermined depth of the semiconductor substrate intended to be a device isolation region to form a device isolation insulating film, and then oxidized to form the groove. Eliminates defects generated during the process, buffers thermal expansion stress generated during the thermal process of forming a device isolation oxide film after forming a nitride spacer, prevents leakage current, and improves the characteristics and reliability of the device, thereby enabling high integration. It's a skill that lets you.

Description

Method of forming device isolation film of semiconductor device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a device isolation film of a semiconductor device. In particular, during the device isolation oxide film formation process of a highly integrated semiconductor device, a groove is formed by etching a portion of a semiconductor substrate, which is intended as a device isolation region, to form a groove, and an oxide film is formed in the groove. Next, the present invention relates to a technology for preventing leakage currents between devices by forming nitride film spacers, thereby improving device characteristics and reliability, thereby enabling high integration of semiconductor devices.

In general, a semiconductor device is composed of an active region in which devices such as a transistor or a capacitor are formed, and an isolation region separating the active regions so that the operation of the devices does not interfere with each other.

Recently, with the trend toward higher integration of semiconductor devices, efforts have been made to reduce the area of device isolation regions, which occupy a large area in semiconductor devices.

As a method of manufacturing the device isolation region, a conventional local oxidation of silicon (hereinafter referred to as LOCOS) method of thermally oxidizing a semiconductor substrate using a nitride film pattern as a mask, or a trench is formed in a semiconductor substrate and embedded in an insulating material. The trench separation method is used. Among them, the LOCOS method is widely used because of its relatively simple process, but the device separation area is large and buzz is generated at the interface, so that lattice defects are generated due to stress on the substrate. have. As described above, in order to reduce the problems caused by Buzzvik, a recess-local oxidation of silicon (R-LOCOS) method is used in which a semiconductor substrate of a predetermined portion is removed to a predetermined depth and then an isolation oxide layer is formed.

Referring to the accompanying drawings, look at the device isolation film manufacturing method of a semiconductor device according to the prior art as follows.

1A to 1C are cross-sectional views illustrating a method of manufacturing a device isolation film of a semiconductor device according to the prior art.

First, the surface of the semiconductor substrate 11 is thermally oxidized to form a pad oxide film 13, and a nitride film 15 is formed on the pad oxide film 13. In this case, the nitride film 15 is formed to have a thickness of 2000 to 2500 kPa.

Next, the nitride layer 15 forms a pattern of the nitride layer 15 by an etching process using an element isolation mask.

Next, a nitride film spacer 17 is formed on sidewalls of the nitride film pattern 15. (See FIG. 1A)

Next, the pad oxide layer 13 and the semiconductor substrate 11 having a predetermined thickness are removed using the nitride layer 15 pattern and the nitride layer spacer 17 as an etching mask. (See FIG. 1B)

Thereafter, a thermal process is performed to form an element isolation oxide film 19. (See FIG. 1C)

In the method of forming a device isolation film of a semiconductor device according to the prior art as described above, a defect occurs due to damage of the semiconductor substrate during a process of etching a semiconductor substrate intended as an element isolation region, and a stress is generated in the nitride film spacer. As a result, a leakage current is generated along the defects generated in the semiconductor substrate during the thermal process for forming the device isolation oxide film, thereby degrading the characteristics and reliability of the device, thereby making it difficult to integrate the semiconductor device.

In order to solve the above problems of the prior art, a groove is formed in a semiconductor substrate intended as a device isolation region, and an oxide film is formed in the groove to minimize leakage current between devices generated when the device isolation film is formed. And to provide a device isolation film forming method of a semiconductor device to improve the reliability.

1A to 1C are cross-sectional views illustrating a method of forming a device isolation film of a semiconductor device according to the prior art.

2A to 2D are cross-sectional views illustrating a method of forming an isolation layer in a semiconductor device according to the present invention.

◈ Explanation of symbols for the main parts of the drawings

11, 12: semiconductor substrate 13, 14: pad oxide film

15, 16: nitride film 17, 20 nitride film spacer

18: oxide film 19, 22: device isolation oxide film

Device isolation film forming method of a semiconductor device according to the present invention for achieving the above object,

Forming a pad oxide film pattern and a nitride film pattern exposing the device isolation region of the semiconductor substrate to expose the semiconductor substrate;

Oxidizing the exposed surface of the semiconductor substrate to form an oxide film;

Forming a nitride film spacer on the structure;

And thermally oxidizing the exposed semiconductor substrate to form a device isolation oxide film.

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

2A to 2D are cross-sectional views illustrating a method of forming an isolation layer in a semiconductor device according to the present invention.

First, a pad oxide film 14 is formed on the semiconductor substrate 12.

At this time, the pad oxide film 14 contains a nitrogen component.

In addition, the nitride film 16 is sufficiently thickly formed on the pad oxide film 14.

Next, the nitride film 16, the pad oxide film 14, and the semiconductor substrate 12 having a predetermined thickness are etched by an etching process using an element isolation mask (not shown). (See Figure 2A)

Subsequently, the semiconductor substrate 12 is oxidized to form an oxide film 18. At this time, the oxide film 18 reduces the defects generated in the process of recessing the semiconductor substrate 12 and buffers thermal expansion stress caused by the nitride film spacer during the subsequent device isolation oxide film formation process. (See Figure 2b)

The nitride film spacer 20 is formed on sidewalls of the nitride film 16, the pad oxide film 14, and the oxide film 18. The nitride film 16 and the nitride film spacer 20 may be formed of polycrystalline silicon. (See FIG. 2C)

Next, a device isolation oxide film 22 is grown in the structure. (See FIG. 2D)

As described above, in the method of forming a device isolation film of a semiconductor device according to the present invention, in order to form a device isolation insulating film, a groove is formed by etching a predetermined depth of an exposed semiconductor substrate to be formed as a device isolation region, and then oxidizing the groove. Eliminates defects generated during the etching process to form an oxide layer, buffers thermal expansion stress generated during the thermal process of forming a device isolation oxide layer after forming a nitride spacer, and prevents leakage current, and improves the characteristics and reliability of the device. There is an advantage to enable high integration accordingly.

Claims (2)

Forming a pad oxide film pattern and a nitride film pattern exposing the device isolation region of the semiconductor substrate to expose the semiconductor substrate; Oxidizing the exposed surface of the semiconductor substrate to form an oxide film; Forming a nitride film spacer on the structure; Forming a device isolation oxide film by thermally oxidizing the exposed semiconductor substrate. The method of claim 1, And the nitride film pattern and the nitride film spacer are replaced with polysilicon.