JPH0611049B2 - Method for manufacturing semiconductor device - Google Patents

Description

The present invention relates to a method for manufacturing a semiconductor device.

[Conventional technology]

As a means for obtaining contact between an element region and a wiring of a semiconductor device, a polycrystalline silicon film which can directly contact the element region and the wiring is used.

FIGS. 2A and 2B are cross-sectional views of a semiconductor chip showing the order of steps for explaining a conventional method for manufacturing a semiconductor device.

As shown in FIG. 2A, an element isolation field insulating film 2 for partitioning an element forming region is formed on the surface of a P-type silicon substrate 1, and an insulating film 3 is formed on the surface including the element forming region. . Next, an N-type diffusion region 5 is selectively formed in the element formation region by an ion implantation method, and a part of the insulating film 3 on the N-type diffusion region 5 is selectively opened to form a contact window. Form.

Next, as shown in FIG. 2B, the N exposed to the window is
A polycrystalline silicon film 4 which covers a part of the type diffusion region 5 and extends on the insulating film 3 and selectively contains an N type impurity is formed, and the polycrystalline silicon film 4 and the N type diffusion region are heat-treated. Get in touch with.

[Problems to be solved by the invention]

In the above-described conventional semiconductor device manufacturing method, the contact contact area cannot be reduced in order to suppress an increase in contact resistance in the diffusion region. That is, the area of the overlapping portion between the diffusion region and the polycrystalline silicon film becomes an obstacle to the planar reduction of the device.

Further, in order to reduce the resistance of the wiring, it is necessary to add a high concentration of impurities to the polycrystalline silicon film. However, since the diffusion region and the polycrystalline silicon film are in direct contact, When the impurities are diffused, or by the heat treatment in the subsequent manufacturing process, the impurities diffuse into the silicon substrate and increase the depth of the diffusion region on the surface of the silicon substrate. This increase in the diffusion region depth shortens the effective separation distance from other diffusion regions and deteriorates the insulation characteristics. Therefore, in order to ensure the insulation between the diffusion regions, the width of the field insulating film must be widened to increase the minimum separation distance, which is a problem for miniaturization of semiconductor elements.

An object of the present invention is to provide a method for manufacturing a semiconductor device that enables miniaturization of semiconductor elements.

[Means for solving problems]

A method of manufacturing a semiconductor device according to the present invention comprises a step of forming a field insulating film for element isolation for partitioning an element forming region on one main surface of a semiconductor substrate of one conductivity type, and an insulating film on a surface including the element forming region. And selectively forming a polycrystalline silicon film on the insulating film, and by using the polycrystalline silicon film and the field insulating film as a mask, impurities are ion-implanted to form a reverse conductivity type diffusion region in the element formation region. A step of forming a contact window by selectively removing the insulating film on the diffusion region using the polycrystalline silicon film as a mask, the polycrystalline silicon film on the insulating film, and A step of forming a refractory metal film on the surface including the diffusion region exposed in the contact window; and a step of heat-treating in an inert gas atmosphere to contact the polycrystalline silicon film in contact with the refractory metal film. Forming a refractory metal silicide film by reacting the surface of the diffusion film and the surface of the diffusion region, and wiring for removing the unreacted refractory metal film and contacting the diffusion region with the refractory metal silicide film And a step of forming.

[Embodiment] Next, an embodiment of the present invention will be described with reference to the drawings.

1A to 1E are cross-sectional views of a semiconductor chip shown in the order of steps for explaining an embodiment of the present invention.

As shown in FIG. 1A, an element isolation field insulating film 2 for partitioning an element forming region is formed on the surface of a P-type silicon substrate 1, and a film thickness of 200 is formed on the surface including the element forming region.
The insulating film 3 of Å is formed. Next, a film thickness of phosphorous was added on the insulating film 3 so that a part thereof overlaps the element forming region.
A polycrystalline silicon film 4 of 4 μm is selectively formed.

Next, as shown in FIG. 1B, the polycrystalline silicon film 4
Arsenic is ion-implanted using the field insulating film 2 as a mask to form an N-type diffusion region 5 in the element forming region. Next, the insulating film 3 on the N-type diffusion region is selectively removed using the polycrystalline silicon film 4 as a mask to form a contact window.

Next, as shown in FIG. 1 (c), the exposed N of the window is
A titanium film 6 having a film thickness of 500 Å is deposited on the surface including the mold diffusion region 5.

Next, as shown in FIG. 1 (d), a treatment is performed for 60 minutes in a nitrogen atmosphere at 600 ° C., and titanium which is in contact with the polycrystalline silicon film 4 on the insulating film 3 and the N-type diffusion region 5 is processed. The film 6 is reacted to form a titanium silicate film 7 having a thickness of about 0.1 μm. At this time, the titanium film 6 on the side wall of the insulating film 3 reacts with the silicon supplied from the upper polycrystalline silicon film 4 and the surface of the lower N-type diffusion region to form a titanium silicide film, and the titanium silicide film 7 is formed. It is formed in contact with the N-type diffusion region and continuously up to the insulating film 3.

Next, as shown in FIG. 1 (e), the unreacted titanium film 6 is removed by a mixed solution of animonia and hydrogen peroxide, and a wiring which contacts the N-type diffusion region and extends on the insulating film 3 is formed. obtain.

In addition to titanium, for example, tungsten, molybdenum, or the like can be used as the refractory metal.

〔The invention's effect〕

As described above, the present invention forms a refractory metal silicide film that contacts the surface of the diffusion region in the element region and extends on the polycrystalline silicon film on the insulating film, thereby removing impurities from the surface of the diffusion region. Since a low resistance contact can be formed without directly contacting the added polycrystalline silicon film, the overlapping area of the diffusion region and the polycrystalline silicon film can be made small, and the increase of the depth of the diffusion region can be suppressed to prevent other diffusion. There is an effect that it is possible to miniaturize the semiconductor element by removing the factor that shortens the effective separation distance from the region.

[Brief description of drawings]

1 (a) to 1 (e) are sectional views of a semiconductor chip shown in the order of steps for explaining an embodiment of the present invention, and FIGS. 2 (a) and 2 (b) are conventional semiconductor device manufacturing methods. FIG. 6 is a cross-sectional view of the semiconductor chip in the order of steps for explaining. 1 ... P-type silicon substrate, 2 ... field insulating film, 3
...... Insulating film, 4 ... Polycrystalline silicon film, 5 ... N type diffusion region, 6 ... Titanium film, 7 ... Titanium silicide film.

Claims (1)

[Claims] 1. A step of forming a field insulating film for element isolation for partitioning an element forming area on one main surface of a semiconductor substrate of one conductivity type, and an insulating film is formed on a surface including the element forming area to perform the insulation. A step of selectively forming a polycrystalline silicon film on the film; a step of implanting impurities with the polycrystalline silicon film and the field insulating film as a mask to form a diffusion region of opposite conductivity type in the element forming region A step of selectively removing the insulating film on the diffusion region using the polycrystalline silicon film as a mask to form a contact window, and exposing the polycrystalline silicon film on the insulating film and the contact window A step of forming a refractory metal film on the surface including the diffusion region, the polycrystalline silicon film which is heat-treated in an inert gas atmosphere and is in contact with the refractory metal film, and the diffusion. A step of reacting the surface of the region to form a refractory metal silicide film; a step of removing the unreacted refractory metal film and forming a wiring contacting the diffusion region by the refractory metal silicide film. A method of manufacturing a semiconductor device, comprising: