KR19980040629A - Salicide Formation Method of Semiconductor Device - Google Patents

Abstract

A method of forming a salicide of a semiconductor device is disclosed. The present invention comprises forming a gate oxide film, a gate electrode and a material film on a silicon substrate, forming a spacer on both sidewalls of the gate electrode and the material film, and implanting impurities into the entire surface of the substrate using the spacer as a mask. Forming a source and drain region, removing the material layer having a higher height than the gate electrode, and selectively forming a silicon layer on the source region, the drain region, and the gate electrode; Forming a metal film on the entire surface of the resultant, and reacting the metal film with the silicon film to form a metal silicide film. According to the present invention, since the silicon film formed on the gate electrode does not overgrow due to the thick spacer, the bridge phenomenon between the gate electrode and the source region / drain region can be suppressed.

Description

Salicide Formation Method of Semiconductor Device

The present invention relates to a method of forming a salicide of a semiconductor device, and more particularly, to a method of forming a salicide of a semiconductor device capable of preventing a bridge between a gate electrode and a source / drain region.

In general, in the semiconductor manufacturing process, a salicide (self-aligned silicide) process in which silicide is formed only by heat treatment at a portion where silicon is exposed such as a gate, a source region, and a drain region is simple and low resistance of the process itself. Because of its contact resistance characteristic, it is used in devices requiring speed. However, the salicide process reacts with silicon, which is the underlying film, to form silicide, resulting in the consumption of silicon. As a result, the junction becomes thin and the salicide process can lead to junction leakage problems.

To solve this problem, a method called selective epi growth (SEG) has been devised to selectively grow single crystal silicon only on silicon. Here, the conventional salicide formation method using SEG method is demonstrated.

1 and 2 are cross-sectional views for explaining a salicide forming method of a semiconductor device according to the prior art.

In FIG. 1, the gate oxide film 5 and the gate electrode 7 are formed on the active region of the silicon substrate 1. The gate electrode 7 is formed using a polysilicon film. Subsequently, spacers 9 are formed on both sidewalls of the gate oxide film 5 and the gate electrode 7. The spacer 9 uses a silicon nitride film.

Next, the source region 11 and the drain region 13 are formed by implanting impurities into the entire surface of the substrate 1 using the spacer 9 as a mask. Subsequently, a silicon film 15 is selectively formed on the surfaces of the silicon substrate 1 and the gate electrode 7. Subsequently, a silicide metal film 17, for example, a Ti film, is formed over the entire surface of the resultant product.

In FIG. 2, the silicon film 15 and the metal film 17 are subjected to rapid thermal processing so that the silicide reaction occurs. In this case, the metal silicide layer 19 is formed on the top surface of the gate electrode 7, the source region 11, and the drain region 13. The unreacted metal film is then removed to complete the salicide process of the semiconductor device.

In the conventional salicide forming method as described above, since the silicon film grows faster on the gate electrode made of polycrystalline silicon than the silicon substrate made of single crystal silicon, the silicon film grows thicker than the source or drain regions on the gate. As a result, the silicide at the top of the gate grows faster than the source region and the drain region in the process of forming the salicide, so that silicide is excessively grown on the spacer, causing a bridge between the gate electrode and the source region and the drain region. have.

Therefore, the technical problem of this invention is providing the salicide formation method of the semiconductor device which can solve the above-mentioned problem.

1 and 2 are cross-sectional views for explaining a salicide forming method of a semiconductor device according to the prior art.

3 to 6 are cross-sectional views illustrating a salicide forming method of a semiconductor device according to the present invention.

According to an aspect of the present invention, there is provided a method of forming a gate oxide layer, a gate electrode, and a material layer on a silicon substrate, forming spacers on both sidewalls of the gate electrode and the material layer, and using the spacer as a mask. Implanting impurities into the entire surface of the substrate to form source and drain regions, removing the material layer having a higher height than the gate electrode, and selectively forming silicon on the source, drain and gate electrodes Forming a film, forming a metal film on the entire surface of the resultant, and reacting the metal film with the silicon film to form a metal silicide film. .

The material film is preferably formed of a PSG film. The metal film is preferably formed of one selected from the group consisting of Co, Ti, Pt, Mo, Ni, and Zr.

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

3 to 6 are cross-sectional views illustrating a salicide forming method of a semiconductor device according to the present invention.

In FIG. 3, a gate oxide film 25, a gate electrode 27, and a material film 28 are formed on the silicon substrate 21. The gate electrode 27 is formed using a polysilicon film, and the material film 28 is formed to a thickness of 3001000 Å using a PSG (phospo-silicate-glass) film. Subsequently, spacers 29 are formed on both sidewalls of the gate electrode 27 and the material layer 28. The spacer 29 uses a silicon nitride film. Next, the source region 31 and the drain region 33 are formed by implanting impurities into the entire surface of the silicon substrate 21 using the spacer 29 as a mask.

In FIG. 4, the material layer 28 is removed to form the spacer 29 higher than the height of the gate electrode 27. In this case, even if the silicon film is formed on the gate electrode 27 in a later step, the bridge phenomenon between the gate electrode 27 and the source region / drain region can be suppressed because it is not excessively grown due to the thick spacer.

In FIG. 5, the silicon film 35 is selectively formed on the surfaces of the source region 31, the drain region 33 and the gate electrode of the silicon substrate 21 to be less than 800 GPa. Subsequently, the silicide metal film 37 is formed on the entire surface of the resultant, for example, Co, Ti, Pt, Mo, Ni, and Zr.

In FIG. 6, the silicon film 35 and the metal film 37 are subjected to rapid heat treatment to cause a silicide reaction. In this case, the metal silicide layer 39 is formed on the source region 31, the drain region 33, and the gate electrode 27. Next, the unreacted metal film 37 is selectively removed to complete the salicide process of the semiconductor device.

As described above, the present invention can suppress the bridge phenomenon between the gate electrode and the source region / drain region because the silicon film formed on the gate electrode does not grow excessively due to the thick spacer.

Claims (3)

Forming a gate oxide film, a gate electrode and a material film on the silicon substrate; Forming spacers on both sidewalls of the gate electrode and the material layer; Implanting impurities into the entire surface of the substrate using the spacers as a mask to form source and drain regions; Removing the material layer having an upper height of the spacer higher than a gate electrode; Selectively forming a silicon film on the source region, the drain region and the gate electrode; Forming a metal film on the entire surface of the resultant product; And Forming a metal silicide film by reacting the metal film with the silicon film. The method of claim 1, wherein the material film is formed of a PSG film. The method of claim 1, wherein the metal layer is formed of one selected from the group consisting of Co, Ti, Pt, Mo, Ni, and Zr.