KR980011919A - Method of manufacturing polycide gate electrode - Google Patents

Abstract

A process for producing a polycide gate electrode is described. A metal silicide layer and a mask layer are sequentially formed on a semiconductor substrate and the mask layer is patterned to form a mask pattern for forming a gate electrode and then the metal silicide layer and the metal silicide layer are formed using the mask pattern. The polysilicon layer is etched to form a gate electrode pattern made of a metal silicide pattern and a polysilicon pattern. Then, a protective oxide film is formed by chemical vapor deposition (PECVD) in which plasma is applied on the resultant product having the gate electrode pattern formed thereon. Therefore, the tungsten suicide layer may be abnormally grown to prevent the tungsten suicide bump from protruding from the sidewall of the gate electrode.

Description

Method of manufacturing polycide gate electrode

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly, to a method of manufacturing a gate electrode of a tungsten polycide structure made of polysilicon and tungsten silicide (WSix).

In order to manufacture a semiconductor device, particularly a transistor having an LDD structure, an oxidation process is performed before patterning a gate electrode and before performing a source / drain ion implantation process. This is to prevent lattice damage of the silicon substrate, which may be generated by high energy ions in the source / drain ion implantation process, and to prevent defects in the gate oxide film caused by the concentration of the electric field due to the edge shape of the gate electrode .

Recently, in order to improve the speed of a semiconductor memory device, a refratory metal, a refratory metal silicide, or a doping metal silicide having properties similar to polysilicon and having an electric resistance value several to several tens of times lower than that of polysilicon, A polycide structure in which a refractory metal silicide is laminated on a polysilicon layer is widely used as a wiring material for a semiconductor device, particularly as a gate electrode material of a MOS transistor. As the refractory metal, tungsten (W), tantalum (Ta), titanium (Ti), molybdenum (Mo), or the like is used.

FIGS. 1A and 2B are cross-sectional views illustrating a method of manufacturing a polycide gate electrode according to the prior art.

First, a gate oxide film 14 is formed on a semiconductor substrate 10 on which a field oxide film 12 is formed, a polysilicon layer, a tungsten silicide layer and an oxide film are sequentially stacked thereon, and then the oxide film is patterned Whereby an oxide film pattern 20 is formed. The gate electrode pattern 22 made of the polysilicon pattern 16 and the tungsten silicide pattern 18 is formed by patterning the tungsten suicide layer and the polysilicon layer using the oxide film pattern 20 as a mask. (Fig. 1A)

Next, the resultant product is subjected to a high-temperature thermal oxidation process to form a protective oxide film 26 for preventing damage to the substrate 10 and damage to the gate oxide film. (Fig. 1B)

According to the conventional method as described above, the protective oxide film 26 is formed through a high-temperature thermal oxidation process to prevent damage to the substrate and damage to the gate oxide film. At this time, the unstable tungsten suicide (WSix) grain of the gate electrode pattern 22 is abnormally grown by this high-temperature thermal oxidation process, and the tungsten suicide hump b protrudes to the side wall of the gate electrode pattern 22. This tungsten suicide hump (b) causes a problem of neighboring gates shorting to each other in forming a contact such as a subsequent storage contact.

Accordingly, it is an object of the present invention to provide a method of manufacturing a polycide gate electrode capable of solving the above problems.

FIGS. 1a and 1b are cross-sectional views illustrating a method for fabricating a polycide gate electrode according to the prior art.

2a and 2b are cross-sectional views illustrating a method of fabricating a titanium polycide gate electrode according to an embodiment of the present invention.

According to an aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: sequentially forming a polysilicon layer, a metal silicide layer, and a mask layer on a semiconductor substrate; Forming a mask pattern for forming a gate electrode by patterning the mask layer; Forming a gate electrode pattern including a metal silicide pattern and a polysilicon pattern by etching the metal silicide layer and the polysilicon layer using the mask pattern; And forming a protective oxide film by using a plasma enhanced chemical vapor deposition (PECVD) method on the resultant product having the gate electrode pattern formed thereon.

Therefore, according to the present invention, it is possible to prevent the tungsten suicide layer from being abnormally grown to protrude the tungsten suicide bump on the sidewall of the gate electrode.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention.

FIGS. 2A and 2B are cross-sectional views illustrating a method of manufacturing a tungsten polycide gate electrode according to an embodiment of the present invention.

2A shows a step of forming a gate electrode pattern 62. A field oxide film 52 is formed on a semiconductor substrate 50 to define an isolation region and an active region in a conventional manner, A gate oxide film 54 is formed through a thermal oxidation method. Next, a polysilicon layer, a tungsten silicide layer, and an oxide film, which are doped with impurities to form conductive films, are sequentially formed by using a chemical vapor deposition method (hereinafter referred to as CVD), and then a photoresist is applied thereon. Thereby forming a photoresist pattern (not shown) for patterning the gate electrode. An oxide film mask 60 is formed by etching the oxide film using the photoresist pattern as a mask and the polysilicon layer 56 and the tungsten silicide layer are patterned by using the oxide film mask 60, A gate electrode pattern 62 composed of a silicide pattern 58 is formed.

2B shows a step of forming the protective oxide film 66. A protective oxide film for preventing the damage of the substrate 50 and the damage of the gate oxide film 54 is formed on the resultant of the gate electrode pattern 62, For example, a PE CVD method. At this time, the PE-CVD process is performed at a lower temperature than the conventional thermal oxidation process, for example, at a temperature of 350 to 400 캜. (For reference, the first phase transformation point of tungsten suicide is known to be around 600 ° C.)

As described above, according to the present invention, a protective oxide film for preventing damage to a substrate and a gate oxide film is formed using a PE-CVD method which can be performed at a temperature lower than the phase transformation point of tungsten silicide, for example, The tungsten suicide layer is abnormally grown to prevent the tungsten suicide bump from protruding from the side wall of the gate electrode. Therefore, it is possible to prevent the defect that the neighboring gate electrodes are short-circuited in the contact.

Claims (2)

Sequentially forming a polysilicon layer, a metal silicide layer, and a mask layer on a semiconductor substrate; Forming a mask pattern for forming a gate electrode by patterning the mask layer; Forming a gate electrode pattern including a metal silicide pattern and a polysilicon pattern by etching the metal silicide layer and the polysilicon layer using the mask pattern; And forming a protective oxide film using plasma enhanced chemical vapor deposition (PECVD) on the resultant product having the gate electrode pattern formed thereon. 2. The method of claim 1, wherein the metal silicide layer is formed of tungsten suicide (WSix). ※ Note: It is disclosed by the contents of the first application.