KR20010082903A - Method for fabricating of semiconductor device - Google Patents

Abstract

PURPOSE: A manufacturing method of a semiconductor device is to form a gate electrode with a low resistance, without causing damage to a gate oxide, and to simplify a manufacturing process. CONSTITUTION: A gate oxide(32) is formed on a semiconductor substrate(31). The first metal layer(33) composed of Ti/TiN is deposited on the gate oxide, and then the second metal layer(35) composed of W is deposited thereon. An insulating layer is then deposited on the second metal layer. The insulating layer is anisotropically etched using a patterned photoresist as a mask to form a capping insulating layer(36a) on the second metal layer. The second and the first metal layers are sequentially etched using the capping insulating layer as a mask to form a gate electrode.

Description

Manufacturing method of semiconductor device {METHOD FOR FABRICATING OF SEMICONDUCTOR DEVICE}

The present invention relates to a semiconductor device, and more particularly to a method for manufacturing a semiconductor device that can reduce the resistance of the gate electrode.

Hereinafter, a manufacturing method of a conventional semiconductor device will be described with reference to the accompanying drawings.

1A and 1B are cross-sectional views illustrating a method of manufacturing a semiconductor device according to a first method, and FIGS. 2A to 2C are cross-sectional views illustrating a method of manufacturing a semiconductor device according to a second method.

In the conventional method of manufacturing a semiconductor device according to the first method, as shown in FIG. 1A, a gate oxide film 2, a polysilicon layer 3, and a barrier metal layer 4 are sequentially deposited on a semiconductor substrate 1, and a barrier is used. A low resistance metal layer 5 is deposited on the metal layer 4.

Thereafter, the insulating film 6 is deposited on the metal layer 5 by an oxide film or a nitride film for forming a cap insulating film later.

Although not shown in the figure, a photosensitive film is coated on the insulating film 6, and the photosensitive film is selectively patterned by exposing and developing so that only the gate forming portion remains.

Subsequently, as shown in FIG. 1B using the patterned photosensitive film as a mask, the insulating film 6 is anisotropically etched to form a cap insulating film 6a, and then the photosensitive film is removed and cleaned.

Next, the gate electrode is formed by anisotropically etching the metal layer 5, the barrier metal layer 4, and the polysilicon layer 3 with the cap insulating film 6a as a mask.

In this case, the cap insulating film 6a is not required to be formed. When the cap insulating film 6a is not formed, the photosensitive film is patterned on the metal layer 5 and then the metal layer 5, the barrier metal layer 4 and the poly are patterned using the patterned photosensitive film. The silicon layer 3 is sequentially etched to form a gate electrode.

Next, in the method of manufacturing a semiconductor device according to the second method, a polysilicon layer is deposited on the gate oxide film 12 after the gate oxide film 12 is formed on the semiconductor substrate 11 as shown in FIG. 2A. Thereafter, the polysilicon layer is anisotropically etched so that only the gate forming region remains in the photolithography process, thereby forming the polygate 13.

Thereafter, after the insulating film is deposited on the semiconductor substrate 11 including the polygate 13, the sidewall insulating film 14 is formed by anisotropic etching so as to remain only on the semiconductor substrate 11 on both sides of the polygate 13.

As shown in FIG. 2B, the gate oxide layer 12 is exposed by removing the polygate 13.

Subsequently, as shown in FIG. 2C, the gate electrode 15 is formed by performing an etching or polishing process to form the same height as the sidewall insulating layer 14 on the gate oxide layer 12 exposed after the metal layer is deposited on the entire surface. do.

The conventional method of manufacturing a semiconductor device as described above has the following problems.

First, when the polysilicon layer is directly deposited on the gate oxide layer, it is difficult to etch to form a vertical profile, and there is a risk of etching damage on the gate oxide layer and a limitation in lowering the gate resistance.

Second, the process of removing the polygate after forming the metal gate and forming the metal gate in the portion thereof is complicated because the etching and the removing process for forming the gate must be performed twice.

The present invention has been made to solve the above problems, and in particular, an object of the present invention is to provide a method for manufacturing a semiconductor device suitable for reducing the resistance of the gate while simplifying the process.

1A and 1B are cross-sectional views illustrating a method of manufacturing a semiconductor device according to a first method.

2A to 2C are cross-sectional views illustrating a method of manufacturing a semiconductor device according to a conventional second method.

3A and 3B are cross-sectional views illustrating a method of manufacturing a semiconductor device in accordance with an embodiment of the present invention.

Explanation of symbols for the main parts of the drawings

31 semiconductor substrate 32 gate oxide film

33: first metal layer 34: barrier metal layer

35 second metal layer 36 insulating film

36a: cap insulation film

A method of manufacturing a semiconductor device according to the present invention for achieving the above object is a step of forming a gate insulating film on a semiconductor substrate, a step of sequentially forming a first, a second metal layer on the gate insulating film, on the second metal layer Forming an insulating film; etching the insulating film to form a cap insulating film on the second metal layer above the gate forming portion; and etching the second metal layer and the first metal layer in sequence using the cap insulating film as a mask. It characterized in that it comprises a step of forming an electrode.

Hereinafter, a manufacturing method of a semiconductor device of the present invention will be described with reference to the accompanying drawings.

3A and 3B are cross-sectional views illustrating a method of manufacturing a semiconductor device in accordance with an embodiment of the present invention.

In the method of manufacturing the semiconductor device of the present invention, as shown in FIG. 3A, the gate oxide film 32 is formed on the semiconductor substrate 31 by thermal oxidation or chemical vapor deposition.

Thereafter, a first metal layer 33 composed of titanium / titanium nitride (Ti / TiN) is deposited on the gate oxide layer 32, and a barrier metal layer 34 is deposited on the first metal layer 33. At this time, the barrier metal layer 34 does not have to be deposited.

The second metal layer 35 made of tungsten is deposited on the barrier metal layer 34.

Thereafter, an insulating film 36 composed of an oxide film or a nitride film is deposited on the second metal layer 35 by chemical vapor deposition.

Although not shown in the figure, a photoresist film is coated on the insulating film 36, and the photoresist film is selectively patterned by exposing and developing so that only the gate forming portion remains.

Subsequently, as shown in FIG. 3B using the patterned photosensitive film as a mask, the insulating film 36 is anisotropically etched to form a cap insulating film 36a. Then, the photosensitive film is removed and cleaned.

Next, the gate electrode is formed by anisotropically etching the second metal layer 35, the barrier gold metal layer 34, and the first metal layer 33 using the cap insulating film 36a as a mask. At this time, when etching the gate electrode, tungsten (W) / TiN / Ti is etched using a MREIT etching equipment.

In the tungsten etching process, SF ₆ and N ₂ gas are used as the etching gas, the pressure proceeds in the range of 5 to 40 mt, and the power is performed in the range of 100 to 300W.

The etching of the first metal layer 33 made of Ti / TiN is performed so that an etch damage is not generated in the gate oxide layer 32 vertically using a mixed gas plasma of Cl, N ₂ , and O ₂ . At this time, the pressure is in the range of 5 to 40mt, and the power is performed in the range of 100 to 300W.

The method of manufacturing the semiconductor device of the present invention as described above has the following effects.

After depositing a metal layer composed of Ti / TiN directly on top of the gate oxide layer and etching using a mixed gas plasma of Cl, N ₂ and O ₂ , it is possible to form a low-resistance gate electrode without damaging the gate oxide layer. The process can be simplified.

Claims (6)

Forming a gate insulating film on the semiconductor substrate, Sequentially forming a first and a second metal layer on the gate insulating film, Forming an insulating film on the second metal layer, Etching the insulating film to form a cap insulating film on the second metal layer on the gate forming portion; And forming a gate electrode by sequentially etching the second metal layer and the first metal layer using the cap insulation layer as a mask. The method of claim 1, wherein the first metal layer comprises titanium / titanium nitride (Ti / TiN). The method of claim 1, wherein the second metal layer is formed of tungsten. The method of claim 1, wherein the etching of the first metal layer is performed by using a mixed gas plasma of Cl, N ₂ , and O ₂ . The method of claim 1, wherein the etching of the second metal layer is performed using SF ₆ and N ₂ gases. The method of claim 1, wherein when etching the first and second metal layers, a pressure is performed in a range of 5 to 40 m torr, and power is maintained in a range of 100 to 300 W.