JPH03253034A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To obtain an ohmic contact of a silicide film with a polycrystalline semiconductor film by a method wherein the vicinity of the interface between the silicide film and the polycrystalline semiconductor film is mixed in a mixed state by an ion implantation through the surface of the polycrystalline semiconductor film, which is formed in a contact hole in the silicide film. CONSTITUTION:A polysilicon film 18 of a prescribed thickness is formed on an Si oxide layer 16 and in a contact hole 17 as a polycrystalline semiconductor film, As ions 19 are implanted through the surface of the film 18 and the vicinity of an interface between a titanium silicide film 15 and the film 18, which is a layer on the film 15, is mixed in a mixed state by an energy of these ions 19. After that, the film 18 is processed into a prescribed pattern by a well-known working technique and a wiring layer consisting of a polysilicon film 12 and the film 15 is connected with a wiring layer consisting of the film 18 in the hole 17. Thereby, the film 15 can be favorably brought into ohmic contact with the film 18.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a semiconductor device such as a semiconductor integrated circuit, and particularly relates to the connection of different types of conductive materials.

[Conventional technology]

Today, manufacturing technology for semiconductor devices has progressed at a remarkable pace, and with the increase in demand in many fields, miniaturization and higher speed are required.As a technology to meet these demands, low-resistivity silicide films are being developed. Emphasis is being placed on the method of making ohmic contact between the silicide film of the parentheses and the upper layer of polysilicon by wiring in a simple process.

FIG. 3 is a cross-sectional view of a conventional method for manufacturing a semiconductor device that achieves such ohmic contact between silicide and polysilicon, and each manufacturing process will be explained below.

As shown in FIG. 3(a), a silicon oxide film 2 is deposited on a silicon substrate 1, an opening 3 is formed in the silicon oxide film 2 by etching, etc., and the natural oxide film on the surface is removed with hydrofluoric acid. Thereafter, a polysilicon film 4 is deposited on the silicon oxide film 2 and in the opening 3, and a tungsten silicide film 5 is further deposited on this polysilicon film 4.

At the same time, as shown in FIG. 3(b), the tungsten silicide film 5 and the polysilicon film 4 are sequentially processed into a predetermined pattern using the same resist mask by well-known photolithography and processing techniques. As shown in C), C
An interlayer insulating silicon oxide film 6 is deposited on the exposed silicon oxide film 2 and tungsten silicide film 5 by a VD method or the like.

Thereafter, as shown in FIG. 3(d), the silicon oxide film 6
A contact hole 7 is formed above the opening 3, and the tungsten silicide film 5 is exposed in the contact hole 7. After removing the natural oxide film on the exposed surface with hydrofluoric acid, as shown in FIG. Then, a polysilicon film 8 is deposited on the silicon oxide film 6 and in the contact hole 7,
The polysilicon film 8 is patterned by a well-known processing technique such as selective etching, and the polycide wiring layer made of the polysilicon film 4 and the tungsten silicide film 5 is connected to the wiring layer of the polysilicon film 8 within the contact hole 7.

At this time, the above-mentioned process of removing the natural oxide film using hydrofluoric acid is necessary in order to obtain a good ohmic contact with low contact resistance when interconnections made of different or similar materials are connected to each other.

In this way, the tungsten silicide film 5. In order to sequentially deposit polysilicon films 8, polysilicon films 4. A natural oxide film is generated on the surface of the tank stencilicide film 5, and in order to obtain good ohmic contact, the natural oxide film must be removed using hydrofluoric acid, which has excellent ability to dissolve oxide films, as described above. , the silicide material is limited to tungsten silicide, etc., which does not dissolve in hydrofluoric acid solutions.

[Problem to be solved by the invention]

In the conventional case, as mentioned above, the silicide material was not dissolved in a hydrofluoric acid solution.
Since it is limited to materials that do not dissolve in RL, salicite (SALICIDE) is produced using the two-step annealing method, which allows for low resistance and excellent workability.
It is possible to use materials such as titanium silicide that are suitable for the 5i1cide) technology, but the process is complicated, making it necessary to use a polycide film, which is made of tungsten silicide, which has a higher resistance than titanium silicide, and is difficult to process. This invention was made to solve the above-mentioned problems, and it makes it possible to use a silicide material suitable for the salicide technology using the two-step annealing method, and also makes it possible to The purpose is to simplify the process.

[Means to solve the problem]

A method for manufacturing a semiconductor device according to the present invention is a method for manufacturing a semiconductor device in which a polycrystalline semiconductor film is formed on a silicide film in ohmic contact with the silicide film. a step of forming a metal film, a step of forming the silicide film by a solid phase reaction between the silicon substrate and the metal film, a step of forming an interlayer insulating film on the silicide film, and a step of forming the interlayer insulating film. forming a contact hole and exposing the silicide film in the contact hole; forming the polycrystalline semiconductor film on the interlayer insulating film and in the contact hole; The method is characterized by including a step of mixing the vicinity of the interface between the silicide film and the polycrystalline semiconductor film into a mixed state by ion implantation.

[Effect]

In this invention, a silicide film is formed by a solid phase reaction between a silicon substrate and a metal film, and ion implantation from the surface of a polycrystalline semiconductor film is formed in a contact hole of an interlayer insulating film on this silicide film. Because the area near the interface between the film and the polycrystalline semiconductor film is mixed into a mixed state, ion implantation energy is reduced without forming an oxide film that prevents ohmic contact at the interface with the silicide film on the silicon substrate, unlike in the conventional method. As a result of mixing, the natural oxide film generated on the surface of the silicide film becomes mixed with the silicide and polycrystalline semiconductor, and there is no need to newly remove the natural oxide film with hydrofluoric acid as in the conventional method. Omic contact with the polycrystalline semiconductor film can be obtained.

〔Example〕

FIG. 1 shows a sectional view of an embodiment of the method for manufacturing a semiconductor device according to the present invention, and each manufacturing step will be explained below.

First, as shown in FIG. 1(a), a silicon oxide film 10 having a thickness of about 1000 layers is formed on a silicon substrate 9, and then an opening 11 is formed in this silicon oxide film 10. A polysilicon film 12 having a thickness of about 1,500 wafers is formed as a silicon substrate on the top and inside the opening 11, and this polysilicon film 12 is processed into a predetermined pattern by a well-known processing technique.

At the same time, as shown in FIG. 1(b), a metal film with a thickness of about 1 mm is formed on the silicon oxide film 0 and the polysilicon film 12.
13,000 titanium films are formed at 600-800℃
The low temperature lamp annealing induces a solid phase reaction between the polysilicon film 12 and the titanium film 13, and as shown in FIG. As shown in the figure (d), the surface layer portion of the titanium layer 13 that does not undergo solid phase reaction is removed, and then
The solid phase reaction layer 14 is stabilized by high-rise lamp annealing at 0.degree. C., and a titanium silicide film 15 is formed by solid phase reaction by a salicide technique using a so-called two-step annealing method, as shown in FIG. 2(e).

Then, as shown in FIG. 1(f), the silicon oxide film 1
A silicon oxide film 16 with a thickness of 1,000 wafers is formed as an interlayer insulating film on the titanium silicide film 15 and on the titanium silicide film 15, and as shown in FIG. After the titanium silicide film 15 is exposed in the hole 17, a polycrystalline semiconductor film is formed on the silicon oxide film 16 and in the contact hole 17, as shown in FIG. A polysilicon film 18 with a thickness of about 1500 nm is formed as shown in FIG.
30 KeV, dose ijk 1~8 x 10
Arsenic (As) ions 19 of 16 ions/ctl are injected from the surface of the polysilicon film 8, and the energy of the As ions 19 causes a mixed state near the interface between the titanium silicide film 15 and the polysilicon film 18 above it. mixed.

At this time, since the surface of the titanium silicide film 15 is not treated with hydrofluoric acid as in the conventional method before forming the polysilicon film 18, a natural oxide film may be generated on the surface of the titanium silicide film 15, or As ions 19 may be implanted. Because it is mixed with titanium silicide and polysilicon by energy, the titanium silicide film 15 and polysilicon film 18
You can have omic contact with.

Thereafter, the polysilicon film 18 is processed into a predetermined pattern using a well-known processing technique, and the wiring layer made of the polysilicon film 12 and the titanium silicide film 15 is connected to the wiring layer made of the polysilicon film 18 in the contact hole 17. .

Therefore, since a titanium silicide film is formed by a solid-phase reaction using salicide technology using a two-step annealing method, it is not limited to the conventional material such as Solizite, and it is possible to appropriately select from a wide variety of materials. No natural oxide film is generated on the surface of the polysilicon film 12, and the conventional hydrofluoric acid treatment process can be omitted.

Furthermore, by mixing with the implantation energy of As ions 19, it is possible to make good omic contact between the titanium silicide film 15 and the polysilicon film 18 without performing hydrofluoric acid treatment on the surface of the titanium silicide film 15 as in the conventional method. can.

FIG. 2 shows a sectional view of another embodiment of the present invention, and each manufacturing process will be explained below.

First, as shown in FIG. 2(a), a silicon oxide film 21 for element isolation with a thickness of approximately 4,000 mm is formed so as to surround a predetermined area on the surface of a silicon substrate 20 as a silicon base. After the defective oxide film is completely removed from the surface of the silicon substrate 20 in a predetermined area, the process shown in FIG.
), a titanium film 22 is formed as a metal film on the silicon oxide film 21 and the silicon substrate 20 to a thickness of about 1000 mm, and the silicon substrate 20 and the titanium film are bonded together by low-temperature lamp annealing at 600 to 800°C. A solid phase reaction with the membrane 22 is induced, and as shown in FIG.
A solid phase reaction layer 23 of OA is formed.

Then, as shown in FIG. 2(d), the titanium layer 2
The surface layer 23 that does not undergo solid phase reaction is removed, and the solid phase reaction layer 23 is stabilized by high-temperature lamp annealing at approximately 850°C. As shown in FIG. A titanium silicide film 24 is formed by phase reaction.

Furthermore, as shown in FIG. 2(f), the silicon oxide film 2
A silicon oxide film 25 with a thickness of about 1,000 wafers is formed as an interlayer insulating film on the titanium silicide film 24 and on the titanium silicide film 24, and as shown in FIG. After the titanium silicide film 24 is exposed in the hole 26, a polycrystalline semiconductor is formed on the silicon oxide film 25 and in the contact hole 26, as shown in FIG. A polysilicon film 27 with a thickness of about 1,500 wafers is formed, and As ions 28 are implanted from the surface of the polysilicon film 27, as shown in FIG. After the vicinity of the interface between the polysilicon film 24 and the polysilicon film 27 above it is mixed into a mixed state, the polysilicon film 27 is buttered.

Therefore, unlike the case of FIG. 1, even if the titanium silicide film 24 is formed by a solid phase reaction between the silicon substrate 20 and the titanium layer 22, the characteristics are different from the titanium silicide film 15 of FIG. However, the same effect as in the case of FIG. 1 can be obtained.

In both of the above embodiments, the titanium film 13. is used as the metal film.
Although we have explained the case where 22 is formed, the present invention is not limited to this, but among the materials suitable for salicide technology using a two-step annealing method such as platinum (pH), palladium (Pd), nickel (Ni), and cobalt (CO), , you can select and use an appropriate one.

Furthermore, it goes without saying that an insulating film such as a silicon nitride film, BPSG, or SOG may be formed instead of each silicon oxide film 10.16, 21.25.

Further, the ions implanted for mixing are not limited to As ions as in the above embodiments, but it goes without saying that ions of boron, boron fluoride, phosphorus, silicon, etc. may also be implanted.

〔Effect of the invention〕

As described above, according to the present invention, since a silicide film is formed by a solid-state reaction between a silicon substrate and a metal film, it is possible to prevent the formation of an oxide film that prevents ohmic contact at the interface between the silicon substrate and the silicide film. Moreover, the ion implantation energy mixes the area near the interface between the silicide film and the polycrystalline semiconductor layer above it into a mixed state.
It is possible to simplify the process and obtain good ohmic contact between the silicide film and the polycrystalline semiconductor film without requiring a new process for removing the native oxide film using hydrofluoric acid as in the past. can.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the manufacturing process of one embodiment of the semiconductor device manufacturing method of the present invention, FIG. 2 is a sectional view showing the manufacturing process of another embodiment, and FIG. 3 is a sectional view showing the manufacturing process of a conventional semiconductor device manufacturing method. FIG. 3 is a cross-sectional view showing the manufacturing steps of the method. In the figure, 12 is a polysilicon film, 1322 is a titanium film, 15.24 is a titanium silicide film, 1.6.25 is a silicon oxide film, 17.26 is a contact hole, and 18
．． 27 is a polysilicon film, 19.28 is an As ion, 2
0 is a silicon substrate. Note that the same reference numerals in each figure indicate the same or corresponding parts. 15 Titanium silicide film diagram (Part 1) 4 Titanium silicide film diagram (Part 2) 19:As ion diagram (Part 2)

Claims (1)

[Claims] (1) In a method for manufacturing a semiconductor device in which a polycrystalline semiconductor film is formed on a silicide film in ohmic contact with the silicide film, a step of forming a metal film in a predetermined region on a film-like or bulk-like silicon substrate; forming the silicide film through a solid phase reaction between the silicon substrate and the metal film; forming an interlayer insulating film on the silicide film; and forming a contact hole on the interlayer insulating film to form the contact. a step of exposing the silicide film to the hole; a step of forming the polycrystalline semiconductor film on the interlayer insulating film and in the contact hole; A method for manufacturing a semiconductor device, comprising the step of mixing near an interface with a polycrystalline semiconductor film into a mixed state.