JPS62118525A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the mutual diffusion between silicon atoms and tungsten atoms as wiring material from occurring while forming the wiring structure resistant to high temperature heat-treatment by a method wherein two layers comprising a titanium nitride layer and a titanium tungsten alloy layer are formed on the connecting part of a diffused layer and a wiring layer formed on a silicon substrate. CONSTITUTION:A titanium film 3 is formed in a contact hole part 4 connecting a silicon substrate 1 with a first wiring and then nitrogen is injected in the interface between the silicon substrate 1 and the titanium film 3 later to form a tungsten film 6. Then titanium nitride, a compound of titanium and implanted nitrogen is formed on the interface between silicon and titanium film by high temperature heat-treatment. Furthermore, an alloy of titanium and tungsten is formed on the interface between the tungsten film and the titanium film. These layers are so effective for diffusion barrier that the tungsten film 6 as the first wiring connecting to the silicon substrate after formation can be heat- treated at high temperature. Resultantly, when a BPSG film 10 flowing at low temperature is applied for the interlayer insulator between the first wiring 6 and the second wiring 12, the BPSG film can be flattened easily.

Description

DETAILED DESCRIPTION OF THE INVENTION 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 semiconductor device having a wiring structure that is stable against heat treatment.

Conventional technology After forming a tungsten silicide film by chemical vapor deposition (CVD) in a contact hole, which is a connection hole between a diffusion layer and wiring formed on a silicon substrate, a tungsten film is continuously deposited. An example of the case where a fine contact hole is filled with a tungsten silicide film and a tungsten film, a first wiring is formed, and then a second wiring is further formed is shown in the steps shown in FIGS. 2(a) to (C). The explanation will be given using forward sectional views.

As shown in FIG. 2(a), an insulating film 3 is formed on the diffusion layer 2 formed on the silicon substrate 1 by the CVD method, and then a contact hole 4 connected to the diffusion layer 2 is formed.

Next, a tungsten silicide film 13 is formed by chemical vapor deposition using SiH4 and WF6 as reaction gases. Thereafter, the reaction gases are changed from 8iH4 and WF6 to WF6 and H2, and a tungsten film 6 is continuously formed. Next, patterning of the wiring made of the tungsten silicide film 13 and the tungsten film 6 is performed. Then the second
1. As shown in Figure (0), a borophosphosilicate glass (BPSG) film 10 for interlayer insulation is formed on the tungsten film 6, and a flow of the BPSG film 1Q is performed by annealing at a high temperature. Finally, a second contact hole 11 is formed to connect the tungsten film and the second wiring.1. /After this, the second wiring A"Fl-C aluminum film 124 is formed by sputtering method! 2. Perform patterning to form the second wiring. .

Problems to be Solved by the Invention By the method described above, a first wiring is formed in contact with a silicon substrate.
When the flow of the G film is carried out at a temperature of about 4800°C and the BPSG film is pacified, as shown in Figure 2 (C) V,
'At the contact hole portion where the silicon substrate contacts the first wiring, a reaction occurs between silicon in the silicon substrate and tungsten in the tungsten sample, and a tungsten silicide layer is formed. This silicidation leads to further erosion of the silicon substrate, and the silicon substrate and the first
The wiring may be short-circuited (-). Therefore, with the conventional method described above, only high-temperature heat treatment is possible.

The present invention solves the above problems and provides a method for manufacturing a semiconductor device that is very effective in VLSI requiring multilayer wiring.

Means to Solve the Problems According to the present invention, 1. After forming a titanium film on the contact pole portion that connects the silicon substrate and the first wiring, nitrogen is injected into the interface between the silicon substrate and the titanium film. A tungsten film is formed, and titanium nitride, which is a compound of titanium and implanted nitrogen, is formed at the interface between silicon and titanium film by high-temperature heat treatment. Further, an alloy of titanium and tungsten is formed at the interface between the tungsten film and the titanium film. First, two layers, a titanium nitride layer and a titanium-tungsten alloy layer, are formed between the silicon substrate and the tungsten film that is the wiring.

Working titanium nitride and alloys of titanium and tungsten (e.g. Ti6W2, Ti4W6, Ti
2WB, etc.) The effect of preventing interdiffusion between Ct silicon atoms and tungsten atoms, which are the wiring material, is extremely effective, that is, the effect as a diffusion barrier. In the case of the present invention 57.-, two layers, a titanium nitride layer and a titanium Q-tungsten alloy layer, can be simultaneously formed on a silicon substrate, so that the reaction between silicon atoms and tungsten atoms is extremely prevented by Vc. This is an effective means and results in a wiring structure that can be sufficiently covered for high-temperature heat treatment.

EXAMPLE Hereinafter, the present invention will be specifically explained in detail using an example of the present invention. FIGS. 1(IL) to 1(d) are sequential cross-sectional views of the manufacturing process of a semiconductor integrated circuit in which two-layer wiring is formed using the present invention.

First, as shown in FIG. 1, a diffusion layer 21 is formed on a silicon substrate 1. After forming an insulating film 3 with a thickness of approximately 1.0 μm using the Pc0VD method, a A contact pole 4 is formed.

Next, as shown in FIG. 2(b)r: 1, after forming a 600 mm thick layer of titanium 5 by sputtering, the entire surface was implanted by ion implantation at an acceleration voltage of 10 KeV and a dose of I x 1.
Nitrogen is implanted under the conditions of 0.016/d to mix the interface between the diffusion layer 2 and titanium 6. Next, as shown in Figure 1(C), approximately 1
, 0 pm thick tungsten film 6 is formed on the entire surface. WF6 and H2 are used as reaction gases. The reaction temperature d1 is about 350°C, and the reaction pressure is 400! It is ITorr.

1. Since the tungsten film 6 is formed under conditions where the growth of the tungsten film is rate-determined by surface reaction, as shown in FIG. is filled with the tungsten film 6 and then removed. Next, after patterning is performed using the tungsten film 6 as a wiring, as shown in FIG. BP of about 1.0 μm
SG film 1o total 1o. Poron and phosphorus concentrations are 4 wt% and JWt, respectively. BPSG film 1o total 1o
It is a filtrate that melts and flows. In this example, 800
Flow and baking of the IIP8G film was performed at °C.

Then, a via hole 11 is formed in a portion where electrical connection between the first wiring and the second wiring is required. Finally, after forming the second wiring, an aluminum film 12 with a thickness of approximately 1.0 μm, by sputtering, patterning is performed. After that, the formation of the second wiring is completed. 11. Even if it is replaced with Tanksten Ribten, it will have almost the same effect and effect as A7. 5. Effects of the invention According to the present invention 1 ～ is applied to the silicon original layer (7, diffusion K") at the connection part between the diffusion layer formed on the silicon substrate and the wiring
``Titanium film 1 ride layer'', and butane and tungsten alloy layer 4', which is easy to form with self-alignment, and which is the first wiring connected to the silicon substrate I7. After forming 17/11'II (1, the processing becomes h] function. Therefore, a BPSG film that flows at low temperature is applied once a month to the interlayer insulation between the first wiring and the first wiring. In the case, the flat J of BPSG film!
Can be easily integrated into one. In the case of normal low-temperature processes, the interlayer insulating film can be made into a dielectric by using an etch-back method or by applying a silica film. -: In contrast to the process that requires a large number of steps, the present invention can be easily fabricated by flow at high temperatures, making it possible to fabricate multi-layered VLSIs. Forming wiring is extremely easy.

[Brief explanation of drawings]

FIG. 1 is a 2-I cross-sectional view showing a method for manufacturing a semiconductor device according to an embodiment of the present invention, and FIG. 2 is a process cross-sectional view showing a conventional method for manufacturing a semiconductor device. 6. Titanium, 6 Tungsten film, 7-... Titanium silicide layer, 8... Titanium nitride layer, 9
...Titanium tungsten layer.

Claims (2)

[Claims] (1) A feature comprising the steps of forming a titanium film on the silicon substrate, injecting nitrogen into the interface between the silicon substrate and the titanium film, and forming a high melting point metal film on the titanium film. A method for manufacturing a semiconductor device. (2) A method for manufacturing a semiconductor device according to claim 1, wherein the high melting point metal film is made of molybdenum or tungsten.