JPH02268426A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To eliminate necessity of removing a polycrystalline Si oxide film, and to form a contact having low electric resistance with high reliability by diffusing impurity on a silicide. CONSTITUTION:An insulating film 2 is formed on a semiconductor substrate 1 formed with a thin diffused layer (n<-> type) 3, and a contact window is formed in the layer 3 by using a resist pattern. Then, the whole surface of the substrate 1 is coated with a polycrystalline Si film 4, covered thereon with a silicide film 5, and a high concentration diffused layer (n<+> typo) 6 is formed from above the film 5 by a thermally diffusing method of P doping, etc. Then, polycide wirings are formed with the resist pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method of manufacturing a semiconductor device, and particularly to the formation of contacts with high reliability and low electrical resistance.

(Prior Art) In recent years, in order to increase the integration and speed of VLSI devices, a two-layer structure of polycrystalline silicon and a high-melting point metal such as silicide, so-called polycide, has come to be widely used as a wiring layer.

FIG. 2 is a diagram showing an example of a conventional polycide wiring forming process for a semiconductor device. In Figure 2, 1 is a semiconductor substrate, 2 is an insulating film, 3 is a thin diffusion layer (n-), 4 is a polycrystalline silicon film, 5 is a silicide film, and 6 is a thick diffusion layer (no).
It is.

Next, the manufacturing method will be explained. First, as shown in FIG. 2(a), about 5,000 people formed an insulating film 2 on a semiconductor substrate 1 on which a thin diffusion layer (n-) 3 was formed using a hot vapor phase growth (CVD) method. A contact window is opened on the thin diffusion layer (n-) using the method. Then the second
As shown in Figure (b), the polycrystalline silicon film 4 is
Approximately 1,500 degrees of adhesion is achieved by method D. Next, Figure 2 (c
), impurities such as phosphorus are diffused from above the polycrystalline silicon film 4 by a thermal diffusion method to form a dense diffusion layer (n'').
form 6.

Thereafter, the oxide film grown on the polycrystalline silicon film 4 is removed using hydrofluoric acid, and then a silicide film 5 is deposited by CVD or the like, as shown in FIG. 2(d). Next, a resist pattern is used to form the silicide film 5. The polycrystalline silicon film 4 is etched at the same time to form a polycide wiring pattern.

(Problem to be Solved by the Invention) However, in the above-mentioned conventional manufacturing method, when removing the thermal oxide film grown on the polycrystalline silicon with hydrofluoric acid after diffusing phosphorus etc. from the polycrystalline silicon, The thermal oxide film on the polycrystalline silicon remains on the surface due to the fine particles inside and the fine particles and moisture during the washing and drying process after removal. If a silicide film is then deposited and etched, the polycrystalline silicon with the oxide film deposited on the surface will not be etched, causing a problem such as short circuits in the polycide wiring.

The present invention solves the above-mentioned conventional problems, and aims to provide a method for manufacturing a semiconductor device for forming contacts with high reliability and low electrical resistance in polycide wiring.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a method for manufacturing a semiconductor device that includes a step of depositing polycrystalline silicon, a step of depositing a silicide film, and a step of depositing an impurity film on the silicide. It has a step of diffusing the .

(Function) Therefore, according to the manufacturing method of the present invention, by diffusing impurities from above the silicide, there is no need to remove the oxide film of polycrystalline silicon, and the polycrystalline silicon having a contact with high reliability and low electrical resistance can be produced. Wiring can be formed.

(Embodiment) FIG. 1 is a cross-sectional view of the manufacturing process of a semiconductor device to which an embodiment of the present invention is applied. In FIG. 1, 1 is a semiconductor substrate;
2 is an insulating film, 3 is a thin diffusion layer (n-), 4 is a polycrystalline silicon film, 5 is a silicide film, and 6 is a thick diffusion layer (n3). Note that the cross-sectional view of the transistor region is omitted. .

Next, the manufacturing process of this example will be explained. First, as shown in FIG. 1(a), an insulating film 2 is formed on a semiconductor substrate 1 on which a thin diffusion layer (n-) 3 is formed by CVD or the like.
A contact window is formed in the thin diffusion layer (n'') 3 using a resist pattern.

Next, as shown in FIG. 1(b), a polycrystalline silicon film 4 is deposited over the entire surface of the semiconductor substrate 1 by low pressure CVD or the like. Furthermore, as shown in FIG. 1(c), a silicide film 5 is deposited on the polycrystalline silicon film 4 by a CVD method or the like, and then, as shown in FIG. 1(d), phosphorus is doped from above the silicide film 5. Dense diffusion layer (n”) by thermal diffusion method such as
form 6. Thereafter, polycide wiring is formed using a resist pattern.

In the above embodiment, the impurity was diffused before forming the polycide wiring, but the same effect can be obtained even if the impurity is diffused after etching is performed using a resist pattern to form the polycide wiring. Furthermore, by using boron or the like as an impurity, a P-type contact can also be formed in a similar manner.

(Effects of the Invention) As is clear from the above embodiments, the present invention provides a wet treatment for removing an oxide film grown on polycrystalline silicon in the phosphorus doping process of a polycrystalline silicon film by diffusing impurities from above the silicide film. is not necessary, and the oxide film on polycrystalline silicon is extremely thin, so when etching with a resist pattern and forming polycide wiring,
Polycide wiring is no longer short-circuited due to polycrystalline silicon etching residue, and highly reliable polycide wiring can be formed. Further, the contact resistance between the dense diffusion layer (no) and the polycide wiring can be reduced to a low value of about 50Ω.

[Brief explanation of drawings]

FIG. 1 is a manufacturing process diagram of a semiconductor device according to an embodiment of the present invention, and FIG. 2 is a manufacturing process diagram of a conventional semiconductor device. DESCRIPTION OF SYMBOLS 1... Semiconductor substrate, 2... Insulating film, 3... Thin diffusion layer (n-), 4... Polycrystalline silicon film, 5... Silicide film, 6... Dense diffusion layer ( no). Figure Figure

Claims (1)

[Claims] A step of depositing an insulating film on a semiconductor substrate, a step of opening a contact window in the insulating film, and a step of depositing a polycrystalline silicon film on the semiconductor substrate exposed on the insulating film and the contact window portion. a step of depositing a refractory metal or its silicide film on the polycrystalline silicon film; and a step of diffusing impurities from above the refractory metal or silicide film. Production method.