JPH0752726B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION [Outline] A method of manufacturing a semiconductor device in which silicide is selectively formed, wherein lateral growth of silicide is controlled by changing a film thickness of a refractory metal to achieve high precision. It is possible to form a silicide having a fine pattern.

[Industrial application field]

The present invention relates to a method for manufacturing a semiconductor device, and more specifically, a refractory metal film is deposited on a patterned silicon layer (Si) and an insulating film, and heat treatment is performed to selectively deposit Si on the Si layer. The present invention relates to a method of forming a silicide on a substrate.

[Prior Art] In recent years, refractory metal silicides have been widely used as electrode materials in semiconductor devices. This is because the refractory metal silicide has excellent heat resistance and low resistance.
Further, it is advantageous because it can be formed only on Si in a self-aligned manner.

FIGS. 7A to 7C are cross-sectional views for explaining a conventional general method for selectively forming silicide. First, the SiO ₂ film 2 is formed on the Si substrate 1. Next, after patterning the SiO ₂ film 2, a refractory metal film 3 is deposited on the entire surface.
(FIG. 5 (a)).

After that, when heat-treated, the Si substrate 1 and the refractory metal film 3 react with each other to gradually grow a silicide film and rise up over the side surface of the SiO ₂ film 2 (FIG. 5B). At this time, the growth of silicide is controlled by changing the heat treatment time and the heat treatment temperature. Next, the refractory metal film 3 is selectively etched. (FIG. 5 (c)).

[Problems to be solved by the invention]

By the way, although it is possible to control the growth of silicide by changing the heat treatment time and the temperature as in the above-mentioned method, there is a problem that sufficient control cannot be achieved by only fine patterning.

The present invention was created in view of the problems of the conventional example, and an object of the present invention is to provide a method for manufacturing a semiconductor device in which a fine silicide pattern can be accurately formed by a simple method.

[Means for solving problems]

According to the present invention, an insulating film is formed on a silicon layer, and after the insulating film is patterned, the silicon layer is covered with a refractory metal, and a silicide reaction is performed to gradually silicide the contact part between the refractory metal and the silicon layer. In the method of manufacturing a semiconductor in which an unreacted refractory metal on an insulating film is etched and then silicide is selectively formed, lateral growth of the silicide is controlled by a film thickness of the refractory metal. It is characterized by being

[Action]

Since the refractory metal film can be formed with a predetermined thickness with high precision, lateral growth of silicide can also be controlled with high precision. Therefore, it is possible to easily form a highly precise fine patterned silicide film.

In particular, if zirconium is used as the refractory metal, by forming the film thickness of zirconium to a predetermined thickness or more,
Lateral growth of zirconium silicide from the contact can be more restricted.

As a result, the mask pattern margin that allows for the lateral growth of the silicide can be made smaller, or the pattern can be formed with almost no consideration, so that the silicide pattern can be made finer.

Furthermore, by performing the silicide reaction in a hydrogen atmosphere,
It is possible to eliminate the irregularities appearing at the interface between the silicide layer generated by the silicidation reaction and the underlying silicon layer, or to reduce the size of the irregularities.

〔Example〕

Next, examples of the present invention will be described. The semiconductor device manufacturing method according to the present invention is basically the same as the conventional manufacturing method shown in FIG. However, the manufacturing method of the present invention is different in that the lateral growth of silicide is accurately controlled by changing the film thickness of the refractory metal.

FIG. 6 is a diagram showing the experimental results, showing the relationship between the film thickness of zirconium (Zr), which is one of the refractory metals, and the length of the silicide that extends over the side surface of the insulating film. The horizontal axis is the Zr film thickness, and the vertical axis is the zirconium silicide (Zr
It shows the length by which Si ₂ ) grows and rises up the SiO ₂ film. The silicide reaction condition at this time is 5% H ₂ + Ar.
The temperature was 650 ℃ for 30 min. By thus changing the film thickness of the refractory metal, the lateral growth of the silicide can be controlled with high accuracy, so that the fine pattern of the silicide can be formed with high accuracy.

FIG. 2 is a top view showing a result of a sample in which a ZrSi ₂ film is selectively formed by such a method, and FIG. 3 is an A view of FIG.
It is a sectional view of -A. The pattern shown by B in FIG. ₂ is SiO ₂
It is the pattern of the film 6, and the hatched region shows the region formed by the ZrSi ₂ film 7 after the Zr film has been removed by etching.

FIG. 4 shows the result of a sample in which a TiSi ₂ film was selectively formed under the same conditions for comparison. The pattern shown in the top view B is the pattern of the SiO ₂ film 6, and the hatched area is the etching area. 3 shows a region formed by the TiSi ₂ film after the Ti film is removed by.

When the ZrSi ₂ film is used as the silicide film as described above, the ZrSi ₂ film has more uniform growth in the lateral direction than the TiSi ₂ film grown in the lateral direction, and therefore a highly precise fine pattern can be generated. .

Next, a case of forming a MOS transistor by the manufacturing method according to the present invention will be described. 5 (a)-(d)
Is an explanatory diagram therefor.

First, a SiO ₂ film 9 and a polysilicon gate electrode 10 are formed on a P-type Si substrate 8 by a well-known process, and then arsenic ions are implanted to form a source 11 and a drain 12, and then CVD SiO ₂
The film 13 is applied (FIG. 5 (a)).

Next, the CVD SiO ₂ film 13 is removed by RIE etching, leaving a portion adhered to the side surface of the polysilicon gate electrode 10. (Fig. 5 (b)).

After that, a Zr film 14 is formed on the entire surface, and 67 in Ar + 5% H ₂ atmosphere is used.
A ZrSi ₂ film 15 is formed by annealing at 0 ° C. The ZrSi ₂ film is formed in the regions of the polysilicon electrode 10, the source 11 and the drain 12. At this time, control is performed so that the lateral silicidation does not grow as much as possible. Therefore, the thickness of the Zr film 14 is set to a predetermined thickness or more. (FIG. 5 (c)).

Next, after removing the unreacted Zr film 14, the interlayer CVD SiO ₂ film 16
To form contact holes in the regions of the source 11 and the drain 12. Further, Al wiring 17 is performed to form a MOS transistor.

As described above, according to the embodiment of the present invention, since the Zr film is used as the refractory metal for forming the silicide, the growth of the silicide can be made uniform. By the Zr film thickness to a predetermined thickness In addition, since the growth of the lateral silicide can be precisely controlled, short ZrSi ₂ film and the source 11 on the gate electrode 10, and the ZrSi ₂ film on the drain 12 from each other It can be created in a self-aligned manner in a state of being close to each other. Therefore, a MOS transistor having a fine pattern can be easily manufactured.

〔The invention's effect〕

As described above, according to the present invention, since the lateral growth of the silicide can be accurately controlled by forming the refractory metal film to a predetermined thickness, it is possible to form a highly precise silicide film having a fine pattern. Is possible.

In particular, when zirconium is used as the refractory metal, it is possible to more accurately form a fine-patterned silicide film by utilizing the uniformity of growth.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of semiconductor manufacturing for explaining a manufacturing method according to an embodiment of the present invention, and FIG. 2 is a lateral view of a ZrSi ₂ film formed by the manufacturing method of the present invention. 3 is a sectional view taken along the line AA in FIG. 2 showing a photograph of the surface of the sample showing the growth in the direction. Figure 4 shows TiS prepared for comparison with the ZrSi ₂ film of Figure 2.
4 is a photograph of the sample surface showing lateral growth of the i ₂ film. FIG. 5 is an explanatory diagram for forming a MOS transistor by the manufacturing method of the present invention, and FIG. 6 shows the relationship between the thickness of the Zr film and the lateral growth of the ZrSi ₂ film for explaining the principle of the present invention. FIG. FIG. 7 is a diagram for explaining a conventional manufacturing method when forming a silicide. 1,5,8 …… Si film 2 …… Insulating film 3 …… Refractory metal 4 …… Silicide 6,9,13,16 …… SiO ₂ film 7,15 …… ZrSi ₂ film 10 …… Polysilicon gate Electrode 11 …… Source 12 …… Drain 14 …… Zr film 17 …… Al wiring

Claims (3)

[Claims] 1. An insulating film is formed on a silicon layer, and after the insulating film is patterned, the silicon layer is covered with a refractory metal, and a silicide reaction is gradually performed from a contact portion between the refractory metal and the silicon layer. In a method of manufacturing a semiconductor device, in which silicide is grown on, and then unreacted refractory metal on the insulating film is etched to selectively form silicide, the refractory metal is formed to have a predetermined thickness or more, A method for manufacturing a semiconductor device, comprising limiting the lateral growth of a silicide that gradually grows from a contact portion. 2. The method for manufacturing a semiconductor device according to claim 1, wherein the refractory metal is zirconium. 3. The method of manufacturing a semiconductor device according to claim 1, wherein the silicidation reaction is performed in a hydrogen atmosphere.