JPH1126397A - Manufacture of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the load on a process, wherein excellent silicide is formed by eliminating adverse effects by a natural oxide film, and a siliside formation by silicon ion implantation and the like is made easy. SOLUTION: This manufacturing method has a process, wherein a metal-based material film 4 for silicidie formation is formed on the surface of a silicon substrate 1, and a silicide film is formed by the reaction of the metal-based material film 4 and silicon. Just before the metal-based material film for silicide formation is formed, a natural oxide film is eliminated from the silicon substrate surface by a treatment such as Ar/H2 plasma and annealing in an H2 atmosphere, in, e.g. a metal-based material film-forming equipment 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a semiconductor device. In particular, a method of manufacturing a semiconductor device, comprising the steps of forming a silicide-forming metal-based material film (metal film or the like) on a surface of a silicon substrate and forming a silicide film by reacting the silicide-forming metal-based material film with silicon. It is about.

[0002]

2. Description of the Related Art Conventionally, in the field of semiconductor devices, continuous miniaturization of element dimensions has been progressing, and in order to suppress an increase in parasitic resistance due to such miniaturization, self-alignment without increasing the number of masks. A silicide process that can be formed is adopted. In the silicide process, typically, a silicide-forming metal-based material film such as a metal film is formed on the surface of a silicon substrate, and a silicide film is formed by a reaction between the silicide-forming metal-based material film and silicon.

On the other hand, a natural oxide film is generally formed on the surface of a silicon substrate mainly by oxygen in the air. In the above-described silicide process, for example, silicide is formed by a thermal reaction after depositing a metal on a silicon substrate, but a natural oxide film on the silicon substrate hinders good silicide formation. That is, for example, a silicide having a small line width and low resistance cannot be formed.

Therefore, conventionally, metals (Ti, Co, Ni, Ta, Pt, Hf, V,
Mainly high melting point metals such as Nb, Cr, Mo, W, Fe, Pd. Prior to depositing a film that can be a silicide-forming material even if it is not a simple metal, a natural oxide film on a silicon substrate is usually wet-processed with diluted hydrofluoric acid. It was peeled off by the treatment.

For example, as shown in FIG. 3, a structure in which a natural oxide film 2 is formed on a silicon substrate 1 is subjected to a dilute hydrofluoric acid treatment, and as shown in FIG. The removed silicon substrate 1 is obtained. In the figure, reference numeral 11 denotes a gate forming a MOS structure, and 12 denotes a gate 11
13 and 14 indicate source / drain diffusion layers.

It is said that hydrogen (H) terminates dangling bonds and hardly grows a natural oxide film on the silicon substrate after the dilute hydrofluoric acid treatment as described above. It is said that stripping of the oxide film and subsequent prevention of growth of the natural oxide film are achieved. However, this is not always the case, and the natural oxide film grows again with the passage of time after the dilute hydrofluoric acid treatment. For example, when the substrate wafer from which the natural oxide film 2 has been removed as shown in FIG. 4A is transported into the metal-based material film forming apparatus 3 as schematically shown by an arrow C, the natural oxide film is transported during the transport C. Will regrow. FIG.
In (b), the regrown natural oxide film is indicated by reference numeral 21.
Therefore, when the metal film which is the metal material film 4 for silicide formation is formed in the metal material film forming apparatus 3, the film 4 is formed on the natural oxide film 21 and is affected by the metal film.

The regrowth of the natural oxide film 21 starts in a relatively short time, particularly when, for example, silicon is heavily doped with impurities.
It is considered that the same tendency occurs when the substrate has damage such as a defect.

In the prior art, after depositing a metal film, silicon ions are implanted or the like, thereby forming defects uniformly on the silicon substrate and breaking and mixing the structure of silicide / native oxide film / silicon. It is customary to facilitate silicide formation.

However, for example, this silicon ion implantation requires a large amount of silicon and has a problem that it takes a long time.

[0010]

As described above, the conventional technique has a problem that the influence of the natural oxide film cannot be completely removed and a good silicide cannot be formed. In addition, the process of facilitating the formation of silicide is heavy, for example, it takes time to implant silicon ions to facilitate the formation of silicide.

The present invention solves the above-mentioned problems of the prior art, and removes the adverse effect of the natural oxide film to form a good silicide. In addition, the present invention reduces the burden of a process for facilitating silicide formation such as silicon ion implantation. It is an object of the present invention to provide a method for manufacturing a semiconductor device which can be reduced in size.

[0012]

A method of manufacturing a semiconductor device according to the present invention comprises forming a silicide-forming metal-based material film on a surface of a silicon substrate, and reacting the silicide-forming metal-based material film with silicon. A method for manufacturing a semiconductor device having a step of forming a silicide film, comprising a step of removing a natural oxide film from the surface of the silicon substrate immediately before forming the metal-based material film for forming a silicide. It is.

According to the present invention, the natural oxide film is removed immediately before forming the metal-based material film for forming silicide.
It is possible to solve the problem caused by the formation of the natural oxide film again due to the passage of time after the removal. That is, the surface of the substrate on which the metal material film for silicide formation such as a metal film is to be formed can be made extremely clean, and thus a silicide process in which a good silicide is formed can be realized.

In the present invention, the natural oxide film is removed from the surface of the silicon substrate immediately before forming the metal-based material film for forming silicide. This is performed, for example, in an apparatus for forming a metal-based material film. In this way, after removing the natural oxide film in the metal-based material film forming apparatus, the metal-based material film can be continuously formed in the same apparatus, and the influence of the natural oxide film generation can be obtained. Can be prevented from occurring at all. For example, after removing a natural oxide film in a metal-based material film forming apparatus, by forming a metal-based material film such as depositing a metal film in a vacuum,
The adverse effect of the natural oxide film on the silicide process can be eliminated.

As means for removing the natural oxide film from the surface of the silicon substrate immediately before forming the metal material film for forming silicide, hydrogen plasma treatment (hydrogen plasma irradiation) or hydrogen annealing (annealing in a hydrogen atmosphere) is used. Can be adopted. According to this, by terminating the surface of the silicon substrate with H, the surface of the substrate can be further stabilized.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. However, needless to say, the present invention is not limited by the following embodiments.

Embodiment 1 In this embodiment described below, the present invention is applied to the manufacture of a miniaturized and integrated MOS semiconductor device.

Referring to FIG. 1 and FIG. FIG. 1 shows a characteristic process of this embodiment, and shows a process in a metal material film forming apparatus 3 (film forming apparatus). FIG. 2 shows a process before film formation.

Referring to FIG. 2 and then to FIG. 1, the steps of this embodiment will be described in order below. In this example, the following steps (1) to (10) are performed. The structure of FIG.
Although the natural oxide film 2 is formed on the substrate 1, this structure is formed through the following steps (1) to (6). Thereafter, the steps (7) to (10) are performed (FIG. 2).
(B), FIG. 1).

(1) An element isolation (not shown) is formed on the silicon substrate 1. Element isolation can be formed by a conventional method such as a LOCOS method or a trench method. To form LOCOS as an example, for example, first, an oxide film for a pad and an antioxidant film formed of a nitrided oxide film or the like are deposited and formed in this order, and a predetermined patterning is performed on the antioxidant film. After that, ion implantation for channel stopper and thermal oxidation for LOCOS formation are performed.

(2) Next, an oxide film of about 10 nm is formed by a thermal oxidation method or the like, and thereafter, ion implantation for forming a well, a channel and the like is performed on each of the n-type MOSFET region and the p-type MOSFET region. Do. Generally, using a resist patterned by photolithography as a mask,
This ion implantation is performed. Further, after the oxide film having a thickness of about 10 nm is peeled off, gate thermal oxidation is performed to form a gate insulating film made of the oxide film.

(3) Next, for example, a CVD (Chemical Vapor) is formed on the gate insulating film thus formed.
Deposition method, for example, 200 nm
Is formed. Thereafter, a gate pattern is formed of a resist film by using a photolithography technique, and the patterned resist film is used as a mask to form, for example, RIE (Reactive Ion Et).
The gate electrode 11 made of polycrystalline silicon is formed by selectively removing the polycrystalline silicon film by the etching method.

(4) Subsequently, the n-type MOSFET region and p
LDD (Lightly Doped D)
(Rain) ion implantation for formation is performed. For example, specifically, for an n-type MOSFET, As is set to 20 ke
Under the conditions of V and 1e14 / cm ² , BF ₂ is ion-implanted into the p-type MOSFET under the conditions of ²⁰ keV and 1e14 / cm ² .

(5) Subsequently, for example, by a CVD method,
For example, a 200 nm-thick SiO ₂ film is
Formed over the entire surface. Thereafter, wide sidewalls made of, for example, SiO ₂ are formed on the side surfaces of the gate electrode 11 by anisotropic etching using the underlying silicon substrate as an etching stopper, thereby forming sidewalls 12.

(6) Subsequently, the n-type MOSFET region and p
The source / drain (S / D) diffusion layers 13,
An ion implantation for forming 14 is performed. For example, specifically,
For an n-type MOSFET, As is 40 keV, 1
Under the condition of e15 / cm ² , BF ₂ is ion-implanted into the p-type MOSFET under the conditions of 40 keV and 1e15 / cm ² . After this ion implantation, heat treatment (annealing) for activating the impurities introduced by this ion implantation is performed. For example, specifically, RTA
(Rapid Thermal Annealing)
Is performed at 1000 ° C. for 30 seconds in a nitrogen atmosphere.

(7) Next, a silicide-forming metal-based material film is formed on the surface of the silicon substrate 1 and the silicide process is performed.
As shown in FIG. 2A, on a silicon material (on a gate electrode 11, and on a silicon substrate 1, particularly, at a source / drain (S
/ D) The natural oxide film 2 is formed on the diffusion layers 13 and 14). In this example, first, the natural oxide film 2 on the gate electrode 11 and the silicon substrate 1 (source / drain high-concentration diffusion layers 13 and 14) is removed by wet processing D. As the wet treatment D, treatment with diluted HF is preferable, and therefore, this treatment was employed in this example. By this wet processing D, a structure from which the native oxide film 2 has been removed is obtained as shown in FIG.

(8) Referring to FIG. After the above-described steps, in this example, in the silicide-forming metal-based material film forming apparatus 3 (film-forming apparatus), immediately before forming the silicide-forming metal-based material film 4 (here, the metal film), the apparatus 3 is used. The natural oxide film 21 formed before being transported into the inside is removed. Here, the following (8-1) Ar / H ₂ plasma treatment or (8-2) annealing treatment in an H ₂ atmosphere is performed. This Ar / H ₂ plasma treatment or annealing treatment in an H ₂ atmosphere is schematically shown in FIG.
Indicated by

(8-1) Ar / H ₂ plasma treatment: Ar / H ₂ plasma treatment is carried out, for example, at room temperature to 250
Perform in the range of about ° C. For example, ECR (Electr
On Cyclotron Resonance plasma (2.45 GHz, B = 875 Gauss) is used.
The mechanism of the Ar / H ₂ plasma treatment in this case is A
r physically sputters the silicon substrate and H ₂ ions chemically etch the silicon substrate (ULSI Technology, McGAW-HI).
LL. INTERNATIONAL EDITION
D, C. Y. CHANG, & S.A. M. Sze. , "A
r / H ₂ plasmacleaning ”).

(8-2) Annealing treatment in H ₂ atmosphere: Annealing treatment in H ₂ atmosphere (800 ° C.) in metal silicide forming metal film forming apparatus 3 (film forming apparatus)
Above), for example, by furnace annealing (furnac).
e. anneal, furnace heat treatment) (ULS, supra)
According to I Technology, from 750 ° C, S
Sublimation of SiO starts due to the reaction of i + SiO ₂ → SiO).

(9) Next, the transfer E is performed in a vacuum, and a metal film is deposited as it is as the metal-based material film 4 for silicide formation to obtain a structure shown in FIG. 1B. The above (8
-1) Ar / H ₂ plasma treatment or (8-2) H ₂
Due to the annealing treatment in the atmosphere, even if the natural oxide film 21 is again formed on the silicon material of the substrate 1 while being transported to the metal material film forming apparatus 3 (film forming apparatus), this is removed. The silicon surface of the substrate 1 is clean. Therefore, a metal film can be deposited on a clean silicon surface. Such a metal material coating 4
If silicon ion implantation is performed after the deposition of the (metal film), good silicide is finally obtained. The burden on silicon ion implantation as a process of mixing metal / natural oxide film / semiconductor substrate in the prior art can be reduced. Specifically, for example, the time for silicon ion implantation can be reduced.

(10) In this example, after the above, annealing is performed, for example, at 600 ° C. for 1 minute to react silicon with the metal film. Subsequently, the unreacted metal film on the SiO ₂ or the like is removed by wet selective etching, and annealing is performed, for example, at 800 ° C. for 1 minute to lower the resistance.

Thereafter, a device is formed using a normal process. Processing of a gate electrode, formation of source / drain regions, formation (for example, deposition) of an interlayer insulating film, formation of a contact hole, formation of a metal wiring, and the like are performed according to a conventional method.

As described above, according to the present embodiment, a metal material film for forming silicide (metal film or the like) is formed on the surface of a silicon substrate, and the metal material film for forming silicide and silicon are formed. In the method of manufacturing a semiconductor device having the step of forming a silicide film by the above reaction, there is an effect that the influence of the natural oxide film can be eliminated and a good silicide can be formed. Further, the load of a process of mixing metal / natural oxide film / semiconductor substrate, such as silicon ion implantation, can be reduced.

[0034]

As described above, according to the method of manufacturing a semiconductor device according to the present invention, a good silicide can be formed by removing the adverse effect of a natural oxide film, and a silicide formation such as silicon ion implantation can be performed. The effect is obtained that the load of the process for facilitating the process can be reduced.

[Brief description of the drawings]

FIG. 1 is a view showing main steps (steps in a metal-based material film forming apparatus) according to a first embodiment of the present invention;

FIG. 2 is a view showing a process (a process before forming a metal-based material film) according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a step of a conventional technique (1).

FIG. 4 is a view showing a step of the conventional technique (2).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Silicon substrate, 11 ... Gate electrode, 12
..Sidewalls, 13, 14... Source / drain diffusion layers, 2... Natural oxide films, 21... Regenerated natural oxide films, 3.
··· Metallic material film for silicide formation, 5 ... Natural oxide film removing step immediately before metal material material film formation (Ar / H ₂ plasma treatment or annealing treatment in H ₂ atmosphere).

Claims (6)

[Claims] A method for manufacturing a semiconductor device, comprising: forming a silicide-forming metal-based material film on a surface of a silicon substrate; and forming a silicide film by reacting the silicide-forming metal-based material film with silicon. A method for manufacturing a semiconductor device, comprising a step of removing a natural oxide film from the surface of the silicon substrate immediately before forming the metal-based material film for forming a silicide. 2. A step of removing a natural oxide film from the surface of the silicon substrate immediately before forming the silicide-forming metal-based material film, in a metal-based material film-forming apparatus. 2. The method for manufacturing a semiconductor device according to item 1. 3. A hydrogen plasma treatment or a hydrogen annealing treatment as a means for removing a natural oxide film from the surface of the silicon substrate immediately before forming the silicide-forming metal-based material film. 2. The method for manufacturing a semiconductor device according to item 1. 4. After the step of removing the natural oxide film from the surface of the silicon substrate, a metal material film for forming a silicide is formed, and then a first heat treatment is performed, followed by a wet selective etching. 2. The method according to claim 1, further comprising the step of performing a second heat treatment. 5. A process for removing a native oxide film from the surface of the silicon substrate by a wet process immediately before the step of removing the native oxide film from the surface of the silicon substrate immediately before forming the metal-based material film for forming a silicide. The method according to claim 1, wherein a removing step is performed. 6. The method according to claim 1, wherein silicon ion implantation is performed after forming the silicide-forming metal-based material film.