JPH03222425A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent generation of erosion of an interface between a silicon board 1 and an insulating film by forming a conductive film on the sidewall of a contact hole of a wiring layer formed inside the wiring layer and the silicon board and by selectively forming a tungsten film on the wiring layer and the conductive film. CONSTITUTION:A conductive film 8 is formed on a sidewall of a contact hole part 7 connecting a silicon board 1 and a wiring layer. Accordingly, since all the inside of the contact hole 7 can react on WF6, growth of tungsten is generated on the whole area inside the contact hole 7 so as to easily bury the inside of the contact hole 7 with tungsten 9. Thereby, the interface between the silicon board 1 and an insulating film 3, that is, erosion generated at the interface between the region where tungsten grows and the region where no tungsten grows can be completely prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to the manufacture of semiconductor devices in semiconductor integrated circuits, with the aim of preventing thinning of wiring at connection holes and forming highly reliable wiring without disconnection. Regarding the method.

Conventional technology A chemical vapor deposition method (CVD method) is used to form a contact hole, which is a connection hole between a diffusion layer and wiring formed on a silicon substrate.
The second example shows the case where the first wiring is formed after forming tungsten and filling a fine contact hole.
The explanation will be given with reference to step-by-step cross-sectional views of FIGS. (a) to (f).

Note that in this description, for the sake of brevity, a description of the transistor formation process will be omitted, and only wiring-related processes will be described.

First, as shown in FIG. 2(a), an insulating film 3 is formed by CVD on a diffusion layer 2 formed on a silicon substrate 1, and then a contact hole 7 connected to the diffusion layer 2 is formed using a photoresist 6 as a mask. form. After that, see Figure 2 (
As shown in b), the photoresist 6 is removed. Next, as shown in FIG. 2(e), S i H4 is added to the reaction gas.
, H2WF6, tungsten 10 is selectively formed in the contact hole 7 by chemical vapor deposition. Subsequently, as shown in FIG. 2(d), the tungsten film 11 is
is formed by a sputtering method. Next, Figure 2 (
As shown in e), using photoresist 5, only the area where the wiring is to be formed is masked, and the other parts of the tungsten film 11 are etched. Finally, the photoresist 5 is removed, and the connection between the diffusion layer 2 and the tungsten film 11 is completed as shown in FIG.

Problems to be Solved by the Invention When tungsten 10 is formed in the contact hole 7 to the diffusion layer 2 formed in the silicon substrate 1 by the above method, at the interface between the diffusion layer 2 and the insulating film 3 at the bottom of the contact hole 7, A phenomenon in which the tungsten 10 erodes (encroachment) occurs. This occurs because W F s reacts with the silicon of the diffusion layer 2 and does not react with the insulating film 3 . As a result, the tungsten 10 penetrates through the diffusion layer 2 and reaches the silicon substrate 1, causing breakdown of the junction. As the miniaturization of semiconductor integrated circuits progresses, the distance between the end of the contact hole 7 and the end of the diffusion layer 2 becomes narrower, and this problem becomes more serious.

The present invention solves the above problems, and includes miniaturization,
Provided is a method of manufacturing a semiconductor device that is very effective in semiconductor integrated circuits that require high integration.

Means for Solving the Problems According to the present invention, a conductive film is formed on the side wall of a contact hole portion connecting a silicon substrate and a wiring layer.

By forming a conductive film on the side surface of the working contact hole, the entire inner surface of the contact hole can react with W F 6, thereby preventing encroachment from occurring at the interface between the silicon substrate and the insulating film. Further, since the wiring pattern is formed before the contact hole is formed and the contact hole is filled with tungsten, there is an advantage that there is a large margin for misalignment between the contact hole and the wiring pattern.

EXAMPLE Hereinafter, the present invention will be specifically explained in detail using an example of the present invention.

FIGS. 1<a) to (g) show that, using the present invention, a diffusion layer formed on a silicon substrate and a wiring layer formed on the -F portion of an insulating film formed on a silicon substrate are connected through connection holes. FIG. 4 is a cross-sectional view showing the manufacturing process of a semiconductor integrated circuit in the case where the connection is performed using the same method. Note that in this description as well, for the sake of brevity, the description of the transistor formation process will be omitted, and only the wiring-related processes will be described.

First, as shown in FIG. 1(a), an insulating film 3 is formed by CVD on a diffusion layer 2 formed on a silicon substrate 1, and then a tungsten silicide film 4 with a thickness of 200 OA is formed by CVD.
Formed by method D. Next, using the photoresist 5 as a mask, areas other than those to be left as wiring are removed by dry etching using plasma, and then the photoresist 5 is removed to obtain a cross-sectional shape as shown in the second step (b). Next, as shown in FIG. 1(C), a photoresist 6 is used as a mask, as shown in FIG. 1(d). Diffusion layer 2
In order to form a contact hole 7 connected to the tungsten silicide III 4 and the insulating film 3, the tungsten silicide III 4 and the insulating film 3 are etched using a dry etching method. After that, the photoresist 6 is removed. Subsequently, as shown in FIG. 1(e), a 200 OA thick tungsten silicide film 8 is coated with carbon.
It is formed using the VD method. Next, as shown in Fig. 1(b), using an anisotropic dry etching method, only the tungsten silicide film 8 on the side wall of the contact hole 7 and the tungsten silicide film 4 formed in the step of Fig. 1(b) are etched. leave. Finally, in order to connect the diffusion layer 2 and the wiring layer, as shown in FIG. 1(g), WF (B
Thickness 5000A by CVD method using SiH4゜H2
Tungsten 9 is selectively formed on the bottom surface of contact I hole 7, the side surface of contact hole 7, and on tungsten silicide film 4 formed as a wiring layer. As a result, contact hole 7 is filled with tungsten 9, and tungsten silicide film 4 and diffusion layer 2 are electrically connected. The wiring formation is completed through the above steps.

In this embodiment, tungsten silicide is used for the wiring layer and the conductive film, but similar effects can be obtained by using tungsten, molybdenum silicide, molybdenum, titanium silicide, titanium, and copper.

Effects of the Invention In the present invention, in order to form a conductive film on the side surface of the contact hole, the entire inner surface of the contact hole is coated with W F s
This allows tungsten to grow throughout the contact hole, making it easy to fill the contact hole with tungsten.
Encroachment that occurs at the interface between the silicon substrate and the insulating film, that is, the interface between the region where tungsten grows and the region where it does not grow, can be completely prevented. Furthermore, since the wiring pattern can be formed before the contact holes are formed, the present invention also has the advantage of increasing the margin for misalignment between the contact holes and the wiring pattern.

[Brief explanation of drawings]

FIGS. 1(a) to 1(g) are process-order cross-sectional views for explaining the manufacturing process of a semiconductor device in one embodiment of the present invention;
Figures (a) to (a) are sectional views in the order of steps for explaining the conventional technology. 1... Silicon substrate, 2... Diffusion layer,
3... Insulating film, 4... Tungsten silicide film, 5, 6... Photoresist, 7...
...Contact hole, 8...Tungsten silicide film, 9,10...Tungsten,
11...Tungsten film.

Claims (2)

[Claims] (1) A process of forming a wiring layer on an insulating film formed on a silicon substrate, a process of forming a connection hole between the wiring layer and the silicon substrate in the wiring layer, and a conductive film on the sidewall of the connection hole. A method for manufacturing a semiconductor device, comprising the steps of forming a tungsten film selectively on the wiring layer and the conductive film by chemical vapor deposition. (2) The wiring layer and conductive film are tungsten silicide,
The method of manufacturing a semiconductor device according to claim 1, wherein the semiconductor device is selected from the metal group consisting of tungsten, molybdenum silicide, molybdenum, titanium silicide, titanium, and copper.