KR20010001373A - A method for forming gate electrode of semiconductor device - Google Patents

Abstract

PURPOSE: A method for manufacturing a gate electrode of a semiconductor device is provided to form the gate electrode preventing a characteristic of a gate electrode and a semiconductor substrate from being deteriorated, by forming an oxidation layer on the entire surface after forming a nitride layer spacer on a sidewall of the gate electrode, and performing an anisotropic etching, and by removing the oxidation layer by a wet method. CONSTITUTION: A gate electrode having a stacked structure of a gate insulating layer, a polycrystalline layer(15) and a mask insulating layer is formed on a semiconductor substrate(11). A nitride layer spacer(19) is formed on a sidewall of the gate electrode. A predetermined thickness of an oxidation layer is formed on the entire surface of the substrate. The oxidation layer is anisotropically etched to form an oxidation layer spacer on a sidewall of the nitride layer spacer. The oxidation layer and the gate insulating layer remaining on the oxidation layer spacer and semiconductor substrate are eliminated by a wet method to form the gate electrode having the nitride layer spacer on a sidewall.

Description

A method for forming gate electrode of semiconductor device

The present invention relates to a method of forming a gate electrode of a semiconductor device, and more particularly, to a technique capable of minimizing a phenomenon in which a semiconductor substrate is damaged when a spacer is formed on a sidewall of a gate electrode.

In general, a transistor is formed of a source / drain junction region by a gate electrode formed of polycrystalline silicon and an impurity ion implantation process.

However, as semiconductor devices have been highly integrated, insulation characteristics with neighboring gate electrodes and conductive wirings are degraded.

In order to solve these problems, insulating film spacers are formed on the sidewalls of the gate electrodes.

In this case, when the gate insulating layer is dry-etched together during or after the etching process of the insulating layer spacer, the surface of the semiconductor substrate may be excessively etched and damaged. On the other hand, when the gate insulating film is not etched during the etching process of the insulating film spacer and is removed by wet etching in a subsequent process, the gate electrode is excessively etched to the side of the gate oxide film under the gate electrode, thereby deteriorating the characteristics of the gate electrode. Is generated. Here, the transient etching process involved in the anisotropic etching process is performed so that the semiconductor substrate is formed to a thickness of less than 100 Å from the top.

1 is a cross-sectional view illustrating a method of forming a gate electrode of a semiconductor device according to the related art, and illustrates a phenomenon in which a disadvantage is caused when the gate oxide film on a surface of a substrate is removed by a wet method.

First, a gate oxide layer 33, a polysilicon 35, and a mask insulating layer 37 are stacked on the semiconductor substrate 31 and etched by an etching process using a gate electrode mask to form a gate electrode.

In addition, a nitride film 39 is deposited on the entire surface and anisotropically etched to form a nitride film 39 spacer on the sidewall of the gate electrode.

Then, the gate oxide film 33 on the surface of the semiconductor substrate except for the lower portion of the gate electrode is removed by a wet method.

At this time, the gate oxide layer 33 formed on the lower portion of the gate electrode is side-etched to deteriorate the characteristics of the gate electrode. (Figure 1)

As described above, the gate electrode forming method of the semiconductor device according to the related art is difficult to perform the damage of the semiconductor substrate to 100 Å or less when the insulating film spacer is formed on the sidewall of the gate electrode, and the gate insulating film is lost due to the phenomenon that the gate insulating film is lost. There is a problem that the characteristics of the electrode is deteriorated.

In order to solve the above problems of the prior art, the insulating film spacer on the sidewall of the gate electrode without damaging the substrate by using the nitride film deposition process, the first dry etching process, the oxide film deposition process, the second dry etching process and the wet etching process It is an object of the present invention to provide a method for forming a gate electrode of a semiconductor device that enables high integration of the semiconductor device without deteriorating the characteristics of the gate electrode.

1 is a cross-sectional view showing a gate electrode forming method of a semiconductor device according to the prior art.

2A to 2D are cross-sectional views illustrating a method of forming a gate electrode of a semiconductor device according to an embodiment of the present invention.

<Description of reference numerals for the main parts of the drawings>

11,31: semiconductor substrate 13,33: gate oxide film

15,35 polysilicon film 17,37 mask oxide film

19,39: nitride film spacer 21: oxide film

Ⓐ: gate oxide loss

In order to achieve the above object, the gate electrode forming method of a semiconductor device according to the present invention,

Forming a gate electrode having a gate insulating film, a polysilicon and a mask insulating film stacked structure on the semiconductor substrate;

Forming a nitride film spacer on the sidewalls of the gate electrode;

Forming a certain thickness of an oxide film on the entire surface;

Anisotropically etching the oxide film to form an oxide film spacer on sidewalls of the nitride film spacer;

And removing the oxide film and the gate insulating film remaining on the surface of the semiconductor substrate by a wet method to form a gate electrode having the nitride film spacer formed on the sidewalls.

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 a gate electrode of a semiconductor device according to an embodiment of the present invention.

First, the gate oxide film 13, the polycrystalline silicon film 15, and the mask oxide film 17 are stacked on the semiconductor substrate 11.

A photoresist pattern (not shown) is formed on the stack structure by an exposure and development process using a gate electrode mask (not shown).

The gate electrode is formed by etching the stacked structure and removing the photoresist pattern so that the semiconductor substrate 11 is exposed as a mask.

Next, a nitride film 19 is formed on the entire surface including the gate electrode.

The nitride film 19 is first dry etched, but is anisotropically etched to form the nitride film 19 spacer.

In this case, the anisotropic etching process is performed under the condition that the difference in etching selectivity between the nitride film 19 and the gate oxide film 13 is 10 or more so that only the nitride film 19 can be etched. (FIG. 2A)

Then, an oxide film 21 is formed on the entire surface at a constant thickness. In this case, the oxide film 21 is formed thicker than the gate oxide film 13. (FIG. 2B)

A second dry etching of the oxide layer 21 is performed, and anisotropic etching is performed to form an oxide layer 21 spacer on the sidewall of the nitride layer 19 on the sidewall of the gate electrode. (FIG. 2C)

In addition, the oxide layer 21 spacer on the semiconductor substrate 11 is removed by a wet method to form a gate electrode having the nitride layer 19 spacer on the sidewall.

In this case, the oxide film 21 prevents damage to the substrate during the anisotropic etching process on the semiconductor substrate 11 and is formed on the spacer sidewall of the nitride film 19 so that the gate oxide film 13 is etched laterally under the gate electrode. It prevents the phenomenon. (FIG. 2D)

As described above, in the method of forming a gate electrode of a semiconductor device according to the present invention, a nitride spacer is formed on a sidewall of a gate electrode, an oxide film is formed on an entire surface, and then anisotropically etched and the oxide film is removed by a wet method. Since the gate electrode can be formed without deteriorating the characteristics of the electrode and the semiconductor substrate, the semiconductor device has an effect of enabling high integration of the semiconductor device.

Claims (2)

Forming a gate electrode having a gate insulating film, a polysilicon and a mask insulating film stacked structure on the semiconductor substrate; Forming a nitride film spacer on the sidewalls of the gate electrode; Forming a certain thickness of an oxide film on the entire surface; Anisotropically etching the oxide film to form an oxide film spacer on sidewalls of the nitride film spacer; Forming a gate electrode having a nitride spacer formed on a sidewall by a wet method of removing the oxide spacer and the oxide layer and the gate insulating layer remaining on the surface of the semiconductor substrate. The method of claim 1, And the oxide film is formed relatively thicker than the gate insulating film.