JPS6298620A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To make a metallic silicide film encroach on a semiconductor substrate side forming the interface between the metallic silicide film and the semiconductor substrate on the initial semiconductor substrate side by a method wherein the metallic silicide film formed by CVD process etc. is oxidized. CONSTITUTION:After removing a part of oxide film 2 to expose an impurity diffused region 3, the overall surface of a semiconductor substrate 1 is coated with a tungsten silicide WSi2 film 4 by CVD process or evaporation process. Next the tungsten silicide film 4 is oxidized at e.g. 950 deg.C in the atmosphere of reducing hydrogen H2 mixed with steam H2O to form an oxide film 5. In this case, the silicon Si to form the oxide film 5 is fed from the diffused layer 3 so that the interface between the tungsten silicide 4 and the diffused layer 3 may be formed nearer the semiconductor substrate 1 side than the case before the oxide film 5 is formed. Finally the oxide film 5 and the tungsten silicide 4 are pattern-formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a semiconductor device, and particularly relates to a method for forming a metal silicide film having good bonding properties to a semiconductor substrate.

[Background of the invention]

In order to suppress the increase in parasitic resistance of circuits due to miniaturization of semiconductor integrated circuits, it is necessary to form a metal silicide film on the diffusion layer to lower the resistance.

One method for this is to form a metal silicide film 24 by causing the metal 26 and the semiconductor substrate 21 to react through a thermal reaction as shown in FIG. However, with this method,
There is a problem that the junction depth of the diffusion layer 23 cannot be made shallow, and the surface of the metal silicide film 24 becomes rough. As a method of avoiding this problem, as shown in FIG. 3, there is a method of depositing a metal silicide film 34 by chemical vapor deposition or the like and forming a pattern by lithography. However, with this method, gold DC
Silica 11! A natural oxide film or the like is present at the interface between J 34 and the diffusion layer 33, making it difficult to obtain a bond with low contact resistance.

For those related to these methods, please refer to Japanese Patent Application Laid-open No. 1983-
No. 200418, No. 59-94819, and the like.

[Purpose of the invention]

An object of the present invention is to provide a good bond between a gold Jρ (silicide) film formed by chemical vapor deposition or vapor deposition and an impurity diffusion layer.

[Summary of the invention]

In order to achieve the above object, the present invention oxidizes a metal silicide film formed by a chemical vapor deposition method or the like to cause the metal silicide film to dig into the semiconductor substrate side, thereby forming an interface between the metal silicide film and the semiconductor substrate. is characterized in that it is formed on the initial semiconductor substrate side.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG.

First, as shown in Figure (a), a part of the oxide film 2 is removed to expose the impurity diffusion layer 3, and then a tungsten silicide (WSiz) film 4 is grown by chemical vapor deposition as shown in Figure (b). It is deposited on the entire surface of the semiconductor substrate 1 by a method or a vapor deposition method. Next, as shown in Figure (c), the tungsten silicide film 4 is heated with reducing hydrogen (Hz) and water vapor (H
20) The oxide film 5 is formed by oxidation at a temperature of, for example, 950° C. in a mixed atmosphere. In this case, since silicon (Si) forming the oxide film 5 is supplied from the diffusion layer 3, the interface between the tungsten silicide 4 and the diffusion layer 3 is closer to the semiconductor substrate 1 than before the oxide film 5 is formed. It is formed.

Next, as shown in FIG. 1(d), patterning of the oxide film 5 and tungsten silicide 4 is performed using a known phosphorography technique.

Here, the metal silicide film is described using tungsten silicide as an example, but other metal silicide films such as molybdenum silicide can also be used.

Further, the diffusion layer 3 can also be formed by mixing an impurity into the width of the metal silicide film 4, forming the oxide film 5, and simultaneously diffusing the impurity toward the semiconductor substrate 1 side.

〔Effect of the invention〕

According to the present invention, the interface between the metal silicide film and the semiconductor substrate is
Formed into an initial semiconductor substrate. As a result, good interfacial properties can be obtained, and a bond with good electrical properties can be formed.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the forming process showing one embodiment of the present invention,
The figure is a cross-sectional view of a conventional forming process. 11.21.31...Semiconductor substrate, 12,22°32
・Oxide film, 13, 23. 33... Impurity diffusion layer, 14
．． 24.34...Tungsten silicide film, ]5...
Oxide film, 26... tungsten film.

Claims (1)

[Claims] A method for forming a bond between an impurity diffusion layer and a metal silicide film in a semiconductor device includes a step of opening a hole in a part of an insulating film on a semiconductor substrate to expose the impurity diffusion layer, and a step of chemical vapor deposition on the semiconductor substrate. A process of depositing a metal silicide film by a method or a vapor deposition method, oxidizing the metal silicide film, and forming an interface between the metal silicide film and the impurity diffusion layer into the semiconductor substrate from the position before oxidation. A method for manufacturing a featured semiconductor device.