JP2565131B2 - Method for manufacturing semiconductor device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for forming a metal wiring in a contact hole having a high aspect ratio.

[0002]

2. Description of the Related Art With the miniaturization of semiconductor devices, the junction depth of diffusion layers formed on the surface of a silicon substrate becomes shallow,
The aspect ratio of the contact hole reaching the diffusion layer provided in the insulating film covering the silicon substrate is high. Along with this, a barrier metal layer is provided at least on the bottom surface of the contact hole. The barrier metal layer has a function of preventing mutual diffusion of metal of the metal wiring and silicon of the diffusion layer and suppressing an increase in contact resistance.

The general structure of a conventional barrier metal layer is
It is as follows. A titanium nitride film is laminated on the titanium silicide film at the bottom surface of the contact hole, and a titanium nitride film is laminated on the titanium film at other portions including the sidewall portion of the contact hole. An example of the method of manufacturing the barrier metal layer includes forming a titanium film by sputtering, forming a titanium nitride film by reactive sputtering in nitrogen gas, and silicifying the titanium film on the bottom surface of the contact hole by heat treatment. The reason why the barrier metal layer has such a structure will be described below. Since the titanium nitride film formed by reactive sputtering has poor adhesion to the insulating film, a titanium film having good adhesion to the insulating film is required. The titanium nitride film has a function of preventing the above mutual diffusion, but if the titanium nitride film directly contacts the diffusion layer, the contact resistance does not decrease. The resistivity of the titanium film itself is lower than the resistivity of the titanium silicide film, but when the titanium film directly contacts the diffusion layer, it has Schottky contact resistance. On the other hand, when the titanium silicide film directly contacts the diffusion layer, ohmic contact resistance is obtained. That is, the titanium silicide film in the barrier metal layer has a function of suppressing an increase in contact resistance. The above heat treatment for siliciding the titanium film,
It is performed at a temperature of 500 ° C. or higher. 750 ℃ ~ 800 ℃
If the heat treatment is performed at a certain temperature, the crystal structure of the titanium silicide film has a C54 structure that is a low resistance phase, but if the temperature is lower than this temperature, the crystal structure of the titanium silicide film has a C49 structure that is a high resistance phase.

In the miniaturized semiconductor device, since the junction depth of the diffusion layer is shallow, the above heat treatment for siliciding the titanium film poses a serious problem. Since the silicon supply source at the time of silicidation is localized in the diffusion layer near the contact hole, the effective depth of the junction of the diffusion layer becomes shallower, and the junction leak resistance deteriorates. Further, when this diffusion layer is a P ⁺ -type diffusion layer having boron as a conductivity type impurity, boron in the diffusion layer near the contact hole is also taken into the titanium silicide film together with silicon, and the impurity concentration near the contact hole is increased. Also decreases and the contact resistance increases. A method for dealing with these problems is disclosed in Japanese Patent Application Laid-Open No. 2-234424.

Referring to FIG. 5 which is a schematic sectional view of the manufacturing process of the semiconductor device, the method of manufacturing the semiconductor device described in the above publication is as follows. First, the surface of the N-type semiconductor substrate 201 and the P ⁺ -type diffusion layer 202, the gate oxide film, and the gate electrode 210 are selectively formed on the surface.
To form a P-channel MOS transistor and the like. An insulating film 203 is deposited on the entire surface. After that, a contact hole 204 reaching the P ⁺ type diffusion layer 202 and the like is formed by reactive ion etching (RIE) using a photoresist film (not shown) as a mask [FIG. 5 (a)].
Next, after removing the photoresist film, a film thickness of 30 is formed on the entire surface.
A polycrystalline silicon film 205 having a thickness of about nm is deposited. BF ₂ ⁺ of 5 × 10 ¹⁵ cm ⁻² is ion-implanted at 30 keV into the polycrystalline silicon film 205 in the region where the P-channel MOS transistor is formed, and rapid heating at about 1000 ° C. is performed in nitrogen gas. . Subsequently, a titanium film 206 having a film thickness of about 50 nm is deposited on the entire surface in the sputtering device,
Further, a titanium nitride film 208 having a film thickness of about 90 nm is deposited [FIG. 5 (b)]. After being taken out from the sputtering device, for example, by annealing in a nitrogen atmosphere at 600 ° C.,
A titanium silicide film 207 is formed by a (silicidation) reaction between the polycrystalline silicon film 205 and the titanium film 206 [FIG. 5 (c)]. Next, an aluminum-silicon-copper alloy film 219 is deposited on the entire surface by sputtering [FIG.
(D)]. Then, the aluminum-silicon-copper alloy film 219, the titanium nitride film 208 and the titanium silicide film 207 are sequentially etched by RIE using a photoresist film (not shown) as a mask, and are connected to the P ⁺ type diffusion layer 202. Metal wiring (not shown) is formed.

In the method for manufacturing a semiconductor device described in the above-mentioned publication, the shape (aperture, aspect ratio) of the contact hole 204 and the film thickness of the polycrystalline silicon film 205, the titanium film 206, the titanium nitride film 208, etc. are relative. If the relationship is neglected, the P ⁺ -type polycrystalline silicon film 205 is inevitably present under the titanium film 206, so that when the titanium silicide film 207 is formed, the junction leak resistance as described above may be prevented. Deterioration and increase in contact resistance in the P ⁺ type diffusion layer 202 can be suppressed. The reduction in the diameter of the contact hole is dominant in increasing the aspect ratio of the contact hole. Correspondingly, it is required to reduce the film thickness of the barrier metal layer. The aperture provided in the insulating film is narrow (for example, 0.
35 μm) When a titanium film or the like is formed in a contact hole having a high aspect ratio by sputtering or the like,
The film thickness of the titanium film or the like on the bottom surface of the contact hole is extremely smaller than the film thickness of the titanium film or the like formed on the upper surface of the insulating film, and it becomes difficult to function as a barrier metal layer.

As a method of forming a barrier metal layer for a contact hole having a narrow aperture and a high aspect ratio, chemical vapor deposition (CVD) has recently been attracting attention. 1989 Journal of Applied Physics (Journal of Applied P
hysics) Volume 65, No. 8, 3212-3218
The page reports the selective growth of a titanium silicide (TiSi ₂ ) film on the bottom surface of the contact hole. In this report, low pressure chemical vapor deposition (LPCVD) using titanium tetrachloride (TiCl ₄ ) gas and monosilane (SiH ₄ ) gas as source gases in the temperature range of 827 to 852 ° C. is used. The deposition rate of the titanium silicide film is 200
nm / min to 2 μm / min. Also, 1991
Year of Applied Surface Science (Journal of Applied Sur
(Face Science) Vol. 53, pp. 11-17, selective growth of titanium silicide film on the bottom surface of contact hole by LPCVD in which titanium tetrachloride gas, hydrogen gas and monosilane gas are rapidly heated to 800 ° C. as raw material gas is reported. ing. The film formation rate of the titanium silicide film is 200 to 800 nm / min. Even with a contact hole having a narrow aperture and a high aspect ratio, according to these methods, the barrier metal layer made of the titanium silicide film is reliably formed on the bottom surface of the contact hole. The titanium silicide film formed by these methods has a C54 structure which is a low resistance phase.

In addition, the 10th V-L-S-I Multilevel Interconnection of 1993
Conference (VLSI Multilevel In
ter Connection Conference
e), Proceedings 405-411, describes a method for depositing a titanium film and a titanium nitride film using plasma-enhanced chemical vapor deposition (referred to as ECR-PECVD) by electron cyclotron resonance using microwaves. ,It has been reported.

Referring to FIG. 6, which is a schematic cross-sectional view of a semiconductor device, formation of a barrier metal layer using ECR-PECVD reported in the 10th V-S-I Multilevel Interconnection Conference. Is performed as follows. First, the silicon substrate 30
A diffusion layer 302 is selectively formed on one surface, an interlayer insulating film 303 is deposited on the entire surface, and a contact hole 304 reaching the diffusion layer 302 is formed in the interlayer insulating film 303. Next, this silicon substrate 301 is inserted into an ECR-PECVD apparatus, and argon gas, hydrogen gas and titanium tetrachloride gas are introduced into this apparatus to generate ECR plasma to promote decomposition of titanium tetrachloride gas. , Contact hole 304
A titanium film 306 is deposited on the surface of the interlayer insulating film 303 including the above. In this state, nitrogen gas is additionally introduced into this device,
A titanium nitride film 308 is formed to cover the titanium film 306.
Subsequently, rapid heating for 20 seconds in a nitrogen atmosphere at 725 ° C. is performed, whereby the titanium film 3 on the bottom surface of the contact hole 304 is removed.
06 reacts with silicon of the diffusion layer 302, and the titanium silicide film 307 is formed only in this portion. Even with a contact hole having a narrow aperture and a high aspect ratio, this method reliably forms a barrier metal layer having a laminated structure including a titanium silicide film and a titanium nitride film on the bottom surface of the contact hole. After that, a metal wiring (not shown) made of, for example, an aluminum-silicon-copper alloy film is formed by a known method. The crystal structure of the titanium silicide film 307 has a high resistance phase C49 structure. According to this method, when the diameter of the contact hole 304 is, for example, 0.6 μm, the contact resistance in the N ⁺ type diffusion layer is 20 to 30 Ω / piece, and the contact resistance in the P ⁺ type diffusion layer is 50 to 70 Ω / piece. It is an individual.

[0010]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The method of forming a barrier metal layer described in Japanese Patent No. 424 publication does not involve the formation of a titanium silicide film by consuming silicon of the diffusion layer, and therefore the effective depth of the junction of the diffusion layer becomes shallow, so that the junction leakage resistance is reduced. Although there is no deterioration, it becomes difficult to form a barrier metal layer on the bottom surface of the contact hole having a narrow aperture and a high aspect ratio. On the other hand, LPCVD or ECR-PECVD solves the problem of forming a barrier metal layer on the bottom surface of a contact hole having a narrow aperture and a high aspect ratio, but consumes silicon in the diffusion layer exposed on the bottom surface of the contact hole. As a result, a titanium silicide film is formed, so that the deterioration of the junction leak resistance becomes actual again. That is, in the conventional technology, there is no method for solving these two problems at the same time.

Therefore, the object of the method of manufacturing a semiconductor device of the present invention is to deteriorate the junction leak resistance due to the decrease in the effective depth of the junction of the diffusion layer and to increase the contact resistance due to the change of the impurity distribution of the diffusion layer. And to facilitate formation of a barrier metal layer on the bottom surface of a contact hole having a narrow aperture and a high aspect ratio.

[0012]

According to a first aspect of a method of manufacturing a semiconductor device of the present invention, an interlayer insulating film is formed on a silicon substrate of one conductivity type having a diffusion layer of the opposite conductivity type provided on the surface thereof. Then, a step of forming a contact hole reaching these diffusion layers in this interlayer insulating film, and removing a natural oxide film on the surface of the diffusion layer exposed at the bottom surface of the contact hole to remove a polycrystalline or amorphous silicon film. On the entire surface, a step of inserting the silicon substrate into a plasma-enhanced chemical vapor deposition apparatus and generating plasma to remove a natural oxide film on the surface of the silicon film, and the plasma-enhanced chemical vapor deposition Titanium tetrachloride gas, hydrogen gas, and carrier gas are introduced into the apparatus, plasma is generated to convert the silicon film into a titanium silicide film, and nitrogen gas is additionally introduced to generate plasma. And a step of forming a titanium nitride film that covers the surface of the titanium silicide film, a metal film that covers the surface of the titanium nitride film is formed, and the metal film, the titanium nitride film, and the titanium silicide film are patterned. Thereby forming a metal wiring connected to the diffusion layer through the contact hole.

Preferably, the formation of the silicon film is a low pressure chemical vapor deposition method or a plasma excited chemical vapor deposition method, and the plasma excited chemical vapor deposition apparatus is a plasma excited chemical agent by electron cyclotron resonance using microwaves. It is a plasma-enhanced chemical vapor deposition apparatus using a vapor-phase growth apparatus or a helicon wave, and removal of a natural oxide film on the surface of the silicon film in the plasma-excited chemical vapor deposition apparatus introduces hydrogen gas to generate plasma. Will be done.

According to a second aspect of the method for manufacturing a semiconductor device of the present invention, an interlayer insulating film is formed on a silicon substrate of one conductivity type having a diffusion layer of the opposite conductivity type provided on the surface thereof, and these diffusion layers are formed. A step of forming a contact hole reaching this interlayer insulating film, and a step of removing a natural oxide film on the surface of the diffusion layer exposed on the bottom surface of the contact hole and forming a polycrystalline or amorphous silicon film on the entire surface. And a step of inserting the silicon substrate into a plasma-enhanced chemical vapor deposition apparatus and generating plasma to remove a natural oxide film on the surface of the silicon film.
Introducing titanium chloride gas, hydrogen gas and carrier gas,
A step of generating plasma to convert the silicon film into a titanium silicide film, further introducing nitrogen gas, and generating plasma to form a titanium nitride film covering the surface of the titanium silicide film; A first metal film covering the surface of the first metal film, and etching back at least the first metal film to leave the first metal film, the titanium nitride film, and the titanium silicide film in the contact hole. And forming a second metal film that covers the surface of the interlayer insulating film including the surfaces of the first metal film, the titanium nitride film, and the titanium silicide film left in the contact hole, and at least this. Patterning the second metal film to form metal wiring connected to the diffusion layer through the contact hole.

Preferably, the formation of the silicon film is a low pressure chemical vapor deposition method or a plasma excited chemical vapor deposition method, and the plasma excited chemical vapor deposition apparatus is a plasma excited chemical agent by electron cyclotron resonance using microwaves. It is a plasma-enhanced chemical vapor deposition apparatus using a vapor-phase growth apparatus or a helicon wave, and removal of a natural oxide film on the surface of the silicon film in the plasma-excited chemical vapor deposition apparatus introduces hydrogen gas to generate plasma. Will be done.
More preferably, the first metal film is made of tungsten or tungsten silicide by the low pressure chemical vapor deposition method.

According to a third aspect of the method of manufacturing a semiconductor device of the present invention, an interlayer insulating film is formed on a silicon substrate of one conductivity type having a diffusion layer of the opposite conductivity type provided on the surface thereof, and the diffusion layers are formed on these diffusion layers. The step of forming the reaching contact holes in this interlayer insulating film, the natural oxide film on the surface of the diffusion layer exposed on the bottom surface of the contact hole is removed, and the surface of these diffusion layers exposed on the bottom surface of these contact holes is removed. A step of selectively forming a polycrystalline silicon film, a step of inserting the silicon substrate into a plasma-enhanced chemical vapor deposition apparatus and generating plasma to remove a natural oxide film on the surface of the polycrystalline silicon film, Titanium tetrachloride gas, hydrogen gas, and carrier gas are introduced into the plasma-enhanced chemical vapor deposition apparatus to generate plasma and convert the polycrystalline silicon film into a titanium silicide film. , Further added introducing nitrogen gas,
A step of generating plasma to form a titanium nitride film covering the surface of the contact hole and the surface of the interlayer insulating film including the surface of the titanium silicide film; and forming a metal film covering the surface of the titanium nitride film. Forming a metal wiring connected to the diffusion layer through the contact hole by patterning the metal film and the titanium nitride film.

Preferably, the plasma-excited chemical vapor deposition apparatus is a plasma-excited chemical vapor deposition apparatus using electron cyclotron resonance using microwaves or a plasma-excited chemical vapor deposition apparatus using helicon waves. Removal of the natural oxide film on the surface of the polycrystalline silicon film in the phase growth apparatus is performed by introducing hydrogen gas and generating plasma.

According to a fourth aspect of the method for manufacturing a semiconductor device of the present invention, an interlayer insulating film is formed on a silicon substrate of one conductivity type having a diffusion layer of the opposite conductivity type on the surface thereof, and these diffusion layers are formed. And forming a contact hole in the interlayer insulating film, the native oxide film on the surface of the diffusion layer exposed on the bottom surface of the contact hole is removed, and the diffusion layer exposed on the bottom surface of the contact hole is removed. A step of selectively forming a polycrystalline silicon film on the surface, and a step of inserting the silicon substrate into a plasma-enhanced chemical vapor deposition apparatus and generating plasma to remove a natural oxide film on the surface of the polycrystalline silicon film Then, titanium tetrachloride gas, hydrogen gas, and carrier gas are introduced into the plasma-enhanced chemical vapor deposition apparatus to generate plasma to transform the polycrystalline silicon film into a titanium silicide film. And a step of selectively forming a tungsten film in the contact hole, and forming a metal film covering the surface of the interlayer insulating film including the surface of the tungsten film formed in the contact hole, Patterning the metal film to form a metal wiring connected to the diffusion layer through the contact hole.

Preferably, the plasma-excited chemical vapor deposition apparatus is a plasma-excited chemical vapor deposition apparatus using electron cyclotron resonance using microwaves or a plasma-excited chemical vapor deposition apparatus using helicon waves. Removal of the natural oxide film on the surface of the polycrystalline silicon film in the phase growth apparatus is performed by introducing hydrogen gas and generating plasma.

[0020]

Next, the present invention will be described with reference to the drawings.

Referring to FIGS. 1 and 2 which are schematic cross-sectional views of a manufacturing process of a semiconductor device, a first embodiment of the present invention is a barrier metal having a contact hole having a narrow aperture and a high aspect ratio. It is a method of forming a layer and a metal wiring, and is as follows.

First, arsenic ions are selectively applied to a predetermined region on the surface of the P-type silicon substrate 101 at an acceleration voltage of 70 keV, 5
^{Implanted at} a dose of × 10 ¹⁵ cm ^-2 and heat-treated for 30 minutes in a nitrogen atmosphere at 900 ° C. to obtain a junction depth (X _jn ).
Of a plurality of N ⁺ type diffusion layers 102 (about 1 μm in the figure)
Only one diffusion layer is shown). Film thickness 10 by thermal CVD using monosilane gas and oxygen gas
A silicon oxide film having a thickness of about 0 mn is deposited, and a BPSG film having a thickness of about 1900 mn is deposited by thermal CVD using monosilane gas, phosphine (PH ₃ ) gas, diborane (B ₂ H ₆ ) gas and oxygen gas. As a result, the two layers of the silicon oxide insulating film 20
An interlayer insulating film 103 having a film thickness of about 00 nm is formed on the entire surface. Then, heat treatment is performed in nitrogen gas to reflow and densify the BPSG film, which is an upper layer of the interlayer insulating film 103. Next, a plurality of contact holes 104a (only one contact hole is shown in the figure) reaching each predetermined position of the N ⁺ type diffusion layer 102 are formed by RIE using a carbon fluoride-based gas. Is formed by. The diameter of the contact holes 104a is about 350 nm, and the aspect ratio of these contact holes 104a is about 5.7 [FIG.
(A)].

Next, a natural oxide film (not shown) on the surface of the N ⁺ type diffusion layer 102 exposed on the bottom surface of the contact hole 104a is removed by a hydrofluoric acid-based solution, and then the film is formed by LPCVD using thermal decomposition of monosilane gas. A polycrystalline silicon film 105a having a thickness of about 10 nm is formed on the entire surface [FIG.
(B)]. Since this polycrystalline silicon film 105a has a film thickness sufficiently smaller than the diameter of the contact hole 104a and can be formed with good isotropy by LPCVD, it has the same film thickness as the upper surface of the interlayer insulating film 103. It is also formed on the bottom surface (and side wall) of the contact hole 104a without any trouble. A PECVD apparatus, which is a film forming apparatus having excellent anisotropy, may be used for forming the polycrystalline silicon film 105a. At this time, the film thickness on the upper surface of the interlayer insulating film 103: the film thickness on the side wall of the contact hole 104a: the film thickness on the bottom surface of the contact hole 104a≈2: 1: 2. If this polycrystalline silicon film 105a is formed by atmospheric pressure chemical vapor deposition (APCVD), it will hinder the film formation on the bottom surface (and side wall) of the contact hole 104a.

An amorphous silicon film may be formed instead of forming the polycrystalline silicon film 105a. PECVD or LPC is used to form the amorphous silicon film.
It is preferable to use VD.

Next, the silicon substrate 101 is mounted on the ECR-PE.
Insert in CVD equipment. In this ECR-PECVD apparatus, a waveguide is placed in a plasma chamber surrounded by a magnetic field coil so that the magnetic flux density in the chamber is 875 Gauss.
Microwaves of 5 GHz are incident, and cyclotron resonance of electrons occurs. Resonant electrons (electrons that have undergone cyclotron resonance) are introduced into the reaction chamber, energy is transferred from these electrons to the source gas, and radicals, ions, etc. necessary for film formation are formed. By the generation of resonant electrons,
This ECR-PECVD apparatus can form a film at a lower temperature than the LPCVD apparatus. In this ECR-PECVD apparatus, first, the silicon substrate 10 is placed under a pressure of about 0.6 Pa.
1 is heated to about 500 ° C. After that, the flow rate is 75sc
cm 2 of argon gas and 25 sccm of hydrogen gas were introduced into the ECR-PECVD apparatus, and ECR plasma was generated to generate polycrystalline silicon film 105a.
The natural oxide film (not shown) formed on the surface is removed.

Subsequently, while the silicon substrate 101 was heated to about 500 ° C., titanium tetrachloride gas was added to the device at 5 ° C.
sccm, hydrogen gas 25 sccm, argon gas 7
Introduce a mixed gas with a flow rate of 5 sccm to obtain 0.1 P
A plasma power of 2 kW is applied under a pressure of about a. In this state, titanium radicals or the like decomposed and produced from titanium tetrachloride react with the polycrystalline silicon film 105a, and this polycrystalline silicon film 105a is converted into a titanium silicide film 107a having a film thickness of about 20 nm. The ECR-PECVD apparatus is originally a film forming apparatus having excellent anisotropy, but since the film formation of the titanium silicide film 107a is a silicidation reaction, the film thickness of the titanium silicide film 107a is the interlayer insulating film 103. The upper surface and the side wall of the contact hole 104a are the same. On the other hand, since the natural oxide film on the surface of the N ⁺ type diffusion layer 102 forming the bottom surface of the contact hole 104a is also removed, the surface layer portion of the N ⁺ type diffusion layer 102 is also converted into the titanium silicide film 105a. The thickness of the titanium silicide film 105a in this portion can be controlled to about 25 nm [FIG. 1 (c)].

Here, regarding the above silicidation reaction,
Supplementary explanation. Samples deposited polycrystalline silicon film on the entire surface of the silicon substrate surface, providing a sample deposited on the entire surface N ⁺ diffusion layer of the sample and the P-type silicon substrate surface by depositing an N ⁺ diffusion layer on the entire surface of the P-type silicon substrate surface After removing the natural oxide film on the surface of each sample, the titanium silicide film was formed under the above-mentioned conditions. According to an experiment by the present inventors, the polycrystalline silicon film, the N ⁺ diffusion layer, and the P ⁺
The speed at which the diffusion layers are converted into titanium silicide films is about 200 nm / min and about 10 to 20 nm, respectively.
/ Min and about 20 to 30 nm / min. The rate at which the amorphous silicon film is converted into the titanium silicide film is higher than the rate at which the polycrystalline silicon film is converted into the titanium silicide film. In consideration of the fact that the polycrystalline silicon film 105a covers the entire surface in this silicidation reaction, Si which is a reaction product in plasma is used.
The end point (time) of the silicidation reaction of the polycrystalline silicon film 105a can be easily measured by observing the intensity of the emission spectrum (wavelength about 280 nm) from the Si—Cl bond in Cl _X that sharply decreases.

The N ⁺ type diffusion layer 1 forming the bottom surface of the contact hole 104a is formed before the polycrystalline silicon film 105a is formed.
02 If the natural oxide film on the surface is not removed, the silicidation reaction does not occur on the surface of the N ⁺ type diffusion layer 102 at the bottom of the contact hole 104a,
The silicidation reaction occurs only in the polycrystalline silicon film 105a. As a result, the contact resistance in the contact hole 104a does not become low. Furthermore, if the natural oxide film on the surface of the polycrystalline silicon film 105a is not removed, the silicidation reaction does not occur at the above temperature and the natural oxide film is formed on the natural oxide film (because the film forming rate is extremely low). An extremely thin titanium film having a film thickness on the order of 1 nm or titanium particles having a particle size on the order of 1 nm is formed.

Subsequently, upon detection of the end point, nitrogen gas having a flow rate of about 8 sccm is additionally introduced into the ECR-PECVD apparatus, and titanium tetrachloride and nitrogen are reacted under ECR plasma. This allows
The titanium silicide film 107a on the upper surface of the interlayer insulating film 103
A titanium nitride film 108a having a film thickness of about 50 nm is deposited on the surface of the. At this time, the contact hole 104 (because the film formed by the ECR-PECVD apparatus has excellent anisotropy).
The thickness of the titanium nitride film 108a on the side wall and the bottom surface of a is
They are about 25 nm and about 50 nm, respectively. The aspect ratio of the contact hole 104a at this stage is
It will be about 7.7, which is higher than the original value (about 5.7).

Next, the silicon substrate 101 is mounted on the ECR-
After being taken out from the PECVD apparatus, it is inserted into the LPCVD apparatus and a tungsten film 109 covering the titanium nitride film 108a is formed by a reduction reaction of tungsten hexafluoride (WF ₆ ) gas with hydrogen gas. The film thickness of the tungsten film 109 on the upper surface of the interlayer insulating film 103 is about 250 nm [FIG. 1 (b)]. Sputtering is not preferable for forming the tin-stained film from the viewpoint of filling the contact hole 104. A tungsten silicide film may be formed instead of the tungsten film 105. The tungsten silicide film has a flow rate ratio of about 20 monosilane gas to 1 tungsten hexafluoride gas,
The film can be formed by LPCVD at 0 to 400 ° C. In order to fill the contact hole 104a sufficiently without forming voids and to make the upper surface of the tungsten film 109 including the portion directly above the contact hole 104a substantially flat, the film thickness of the tungsten film 109 is set. Is required to be 200 nm even if it is thin. If a metal wiring made of a tungsten film is to be formed, the thickness of the tungsten film is preferably about 500 nm.

Next, using argon gas as a carrier gas, 6
The tungsten film 109, the titanium nitride film 108a, and the titanium silicide film 107a on the upper surface of the interlayer insulating film 103 are sequentially etched back by isotropic plasma etching using sulfur fluoride (SF ₆ ) gas and oxygen gas as etchant gases. Then, the tungsten film 109a, the titanium nitride film 108aa, and the titanium silicide film 107aa are left in the contact hole 104a [FIG. 2 (a)].

Incidentally, by removing only the tungsten film 109 on the upper surface of the interlayer insulating film 103, the titanium nitride film 108a and the titanium silicide film 107 on the upper surface of the interlayer insulating film 103 are removed.
When it is desired to leave a, the tungsten film 109 having a thickness of, for example, about 150 nm is etched and removed by the above isotropic plasma etching using argon gas as a carrier gas and sulfur hexafluoride gas and oxygen gas as etchants. Further, argon gas is used as a carrier gas and sulfur hexafluoride gas is used as an etchant gas (anisotropic).
The remaining tungsten film 109 on the upper surface of the interlayer insulating film 103 may be removed by etching by RIE. This RIE
Has a high etching selectivity with respect to tungsten, and the titanium nitride film 108a and the titanium silicide film 107a are
Is hardly etched. Furthermore, when forming a metal wiring made of a tungsten film, the photoresist film is masked and the tungsten film is patterned by the RIE. Further, using this photoresist pattern as a mask, boron trichloride (BCl ₃ )
The titanium nitride film and the titanium silicide film may be patterned by RIE using gas and chlorine gas as the etchant gas.

Next, a titanium film 116 and a titanium nitride film 118 are sequentially formed on the entire surface by sputtering and reactive sputtering, and an aluminum film 119a, for example, is formed on the entire surface by sputtering [FIG. 2].
(B)]. Note that a titanium nitride film may be further formed over the aluminum film 119a by sputtering.
Further, instead of the aluminum film 119a, an aluminum alloy film such as an aluminum-silicon alloy film, an aluminum-silicon-copper alloy film or an aluminum-germanium alloy film may be used, and further a copper film may be used. Furthermore, instead of forming the tungsten film 109 and the aluminum film 119a after forming the titanium nitride film 108a, LPC is used.
It is also possible to use an aluminum film an organoaluminum formed by thermal decomposition of such VD or PECVD, for example, by triisobutyl aluminum _{(Al (i-C 4 H} 9) 3).

Then, using a photoresist pattern (not shown) as a mask, the aluminum film 119a, the titanium nitride film 118 and the titanium film 117 are patterned by RIE using boron trichloride gas and chlorine gas as etchants. As a result, the metal wiring 120a is formed by sequentially stacking the titanium film 117a, the titanium nitride film 118a, and the aluminum film 119aa [FIG. 2 (c)].

Referring to FIG. 3, which is a graph showing the intensity distribution of the X-ray diffraction spectrum of the titanium silicide film 107a immediately after the film formation in the first embodiment, the crystal structure of the titanium silicide film 107a has a low resistance phase. Is a C54 structure. This fact means that a heat treatment at about 750 to 800 ° C. was required to obtain a titanium silicide film having a C54 structure, and that the 10th V-S-I multilevel in 1993 mentioned above was required. -In the report of Interconnection Conference Proceedings pp. 405-411, it contradicts that the crystal structure of the titanium silicide film after the heat treatment at 700 ° C was the C49 structure.

In ECR-PECVD, it is presumed that the C54 structure at a substrate temperature of about 500 ° C. is due to the following reasons. Due to the resonance electrons having high energy, hydrogen radicals having high energy, excited hydrogen atoms and the like are easily generated from hydrogen gas. Due to these resonance electrons, hydrogen radicals, etc., titanium tetrachloride gas is more and more easily reduced, and titanium radicals, titanium ions, etc. having high energy are more likely to be separated and produced. In addition, due to these resonance electrons, hydrogen radicals, etc., unsaturated bonds and Si—H bonds are likely to be formed in the polycrystalline silicon film 105a, and these radicals and titanium radicals having high energy are formed. , Reacts with titanium ions. That is, since the titanium radicals or the like that react with the polycrystalline silicon film 105a (which contains a large amount of unsaturated bonds or Si—H bonds) have high energy, the substrate temperature is about 500 ° C. Regardless, the titanium silicide film 107a having the C54 structure of the low resistance phase is obtained. On the other hand, in the selective formation of the titanium silicide film in the contact hole by LPCVD, since this reaction is an almost pure chemical reaction, in order to obtain a titanium silicide film having a C54 structure of a low resistance phase, a substrate at 750 ° C. or higher is used. Temperature is required.

Further, the conversion speed of the silicon film such as the amorphous silicon film or the polycrystalline silicon film into the titanium silicide film is higher than the conversion speed of the N ⁺ diffusion layer and the P ⁺ diffusion layer into the titanium silicide film. It is considered that the density of unsaturated bonds and Si—H bonds in the silicon film at the film forming stage is extremely higher than that of the diffusion layer.

According to the first embodiment, since the titanium silicide film or the like is formed by ECR-PECVD after forming the contact hole, the barrier metal layer on the bottom surface of the contact hole having a narrow aperture and a high aspect ratio. Formation is facilitated. Further, the titanium silicide film having the C54 structure of the low resistance phase can be formed without raising the temperature to increase the depth (X _j ) of the diffusion layer. Furthermore, since the polycrystalline silicon film formed on the surface of the diffusion layer and only the very surface layer of the diffusion layer can be converted into the titanium silicide film with good controllability, X _j is not effectively made shallow. Moreover, the distribution of impurities in the diffusion layer is not changed. Therefore, it becomes easy to simultaneously suppress the increase in contact resistance and the deterioration in junction leak resistance.

In the conventional method of selectively forming a titanium silicide film on the contact hole portion by LPCVD,
When the gate electrode is made of silicide, polycide or refractory metal, it is impossible to form a titanium silicide film in the contact hole for the gate electrode, and it is impossible to suppress the increase in contact resistance in this portion. . If the first embodiment is adopted, silicide,
In the contact hole for the gate electrode made of polycide or refractory metal, it is possible to prevent the contact resistance between the metal wiring and the gate electrode from increasing.

Although the first embodiment is applied to the contact hole reaching the N ⁺ type diffusion layer formed on the surface of the P type silicon substrate, the present embodiment is not limited to this. The present invention can also be applied to a contact hole reaching an N ⁺ type diffusion layer formed on the P well surface, an N type silicon substrate, a P ⁺ type diffusion layer formed on the N well surface, or the like. In addition, bipolar, CMOS or BiCO
It is also applicable to semiconductor devices such as M. Here, a specific example regarding the contact resistance will be shown. The diameter of the contact hole 105a in this embodiment is 350 nm.
For example, an N well is formed on the surface of a P type silicon substrate, and an N ⁺ type diffusion layer and a P ⁺ type diffusion layer are further formed.・ As in the case of the report on Multi-level Interconnection Conference Proceedings pp. 405-411, contact holes were formed to reach these diffusion layers with a diameter of about 0.6 μm, this example was applied, and the contact resistance was measured. did. When this embodiment is applied, the contact resistance in the N ⁺ type diffusion layer is 10 to 15 Ω / piece (20 in the case of the above report).
~ 30Ω / piece), the contact resistance in the P ⁺ type diffusion layer is 3
The value was 0 to 40 Ω / piece (50 to 70 Ω / piece in the above report).

Furthermore, in this embodiment, the ECR-PECVD apparatus was used to form the titanium silicide film and the titanium nitride film, but PECVD (HW-P) by helicon wave was used.
ECVD) equipment can also be used. The present embodiment is applicable to a silicon wafer having a diameter of 6 inches or less due to the limitation of uniformity of plasma density. However, HW-PEC is applicable.
The VD device can also be applied to silicon wafers with a diameter of 8 inches or more.

Referring to FIG. 4, which is a schematic cross-sectional view of the manufacturing process of the semiconductor device, the second embodiment of the present invention is a manufacturing method in which the effective aspect ratio of the contact hole immediately before the formation of the metal wiring is lowered. , Is as follows.

First, as in the first embodiment, a plurality of Ns are selectively formed in a predetermined region on the surface of the P-type silicon substrate 101.
^{A +} type diffusion layer 102 (only one diffusion layer is shown in the figure) is formed, an interlayer insulating film 103 having a film thickness of about 2000 nm is formed on the entire surface, and this interlayer insulation is performed by heat treatment in nitrogen gas. The film 103 is densified. Next, by the same method as in the first embodiment, a plurality of contact holes 104b reaching respective predetermined positions of the N ⁺ type diffusion layer 102 (only one contact hole is shown in the figure). To form. The diameter of these contact holes 104b is also about 350 nm, and the aspect ratio of these contact holes 104b at this stage is also about 5.7. Next, the contact hole 104b
The native oxide film (not shown) on the surface of the N ⁺ type diffusion layer 102 exposed on the bottom surface is removed with a hydrofluoric acid-based solution. Then, the silicon substrate 101 is inserted into an LPCVD apparatus, the substrate temperature is set to about 600 ° C., and dichlorosilane (SiCl ₂ H ₂ ) is added.
Gas and hydrogen chloride (HCl) gas are introduced into this LPCVD apparatus to selectively grow a polycrystalline silicon film 105b having a film thickness of, for example, about 100 nm on the surface of the N ⁺ type diffusion layer 102 at the bottom of the contact hole 104b [FIG. a)].

Next, the silicon substrate 101 is inserted into the ECR-PECVD apparatus used in the first embodiment.
Under the pressure of about 0.6 Pa, the silicon substrate 101 is moved to 50
After heating to about 0 ° C., an argon gas of about 75 sccm and a hydrogen gas of about 25 sccm are introduced into this device,
The polycrystalline silicon film 1 is generated by generating ECR plasma.
The native oxide film (not shown) on the surface of 05b is removed.

Subsequently, as a first step, in a state where the silicon substrate 101 is heated to about 500 ° C., 10 sccm of titanium tetrachloride gas and 25 s of hydrogen gas are added to this apparatus.
A mixed gas having a flow rate of ccm and an argon gas of 100 sccm is introduced, and a plasma power of 2 kW is applied for about 1 to 2 seconds under a pressure of about 0.1 Pa. This is for facilitating the silicidation reaction to occur uniformly. Next, in the second stage, titanium tetrachloride gas is 5 sccm, hydrogen gas is 200 sccm, and argon gas is 100 sccc.
The mixing ratio is changed so that the flow rate is m, and a plasma power of 2 kW is applied for about 10 minutes under a pressure of about 0.1 Pa. By these two-step silicidation reaction, titanium radicals decomposed and produced from titanium tetrachloride react with the polycrystalline silicon film 105b and the N ⁺ type diffusion layer 102,
The polycrystalline silicon film 105b having a thickness of about 100 nm and the surface layer portion of the N ⁺ type diffusion layer 102 having a thickness of about 10 nm are converted into a titanium silicide film 107b having a thickness of about 220 nm. The flow rate ratio of hydrogen gas in the silicidation reaction in the second stage is higher than the flow rate ratio of hydrogen gas in the first embodiment. This is because the exposed area of the polycrystalline silicon film 105b of this embodiment is extremely smaller than the surface area of the polycrystalline silicon film 105a of the first embodiment, so that the conversion rate of silicidation in this embodiment is low. This is because The velocities in the second stage at which the polycrystalline silicon film and the N ⁺ diffusion layer are converted into the titanium silicide film are about 20 nm / min and about 2 nm / mi, respectively.
n (each 1/10 of the conversion speed of the first embodiment described above)
Degree). In this silicidation reaction for about 10 minutes, a titanium film (not shown) having a film thickness of about 1 nm or titanium particles (not shown) having a diameter of about 1 nm are formed on the upper surface of the interlayer insulating film 103 and the side wall of the contact hole 104a. (Fig. 4 (b)).

Next, nitrogen gas having a flow rate of 8 sccm is additionally introduced into the ECR-PECVD apparatus, and the flow rates of titanium tetrachloride gas, hydrogen gas and argon gas are each 5 s.
ccm, 25sccm and 75sccm,
The titanium nitride film 108b is formed by applying a plasma power of 2 kW under a pressure of about 0.1 Pa. At this time, the titanium film or titanium particles are also nitrided. Upper surface of interlayer insulating film 103, contact hole 104b
The film thicknesses of the titanium nitride film 108b on the side wall and the bottom surface are about 50 nm, about 25 nm and about 50 nm, respectively. The aspect ratio of the contact hole 104b at this stage is about 6.0, which is lower than the value (about 7.7) of the first embodiment. In this embodiment, the titanium nitride film 108b directly covers the interlayer insulating film 103, and no titanium film or titanium silicide film is interposed between them. This titanium nitride film 108b is (ECR-P
Since it is formed with high energy (due to ECVD), the titanium nitride film 108b is different from the usual case.
The adhesion between the interlayer insulating film 103 and the interlayer insulating film 103 is high.

After taking out the silicon substrate 100 from the above apparatus, an aluminum film 119b is formed by high temperature sputtering in which the silicon substrate 101 is heated to about 400 ° C. [FIG. 4 (c)]. In the first embodiment described above, it is difficult to form the wiring only with the aluminum film without filling the contact hole 104a with another metal, but in the present embodiment, the aspect ratio of the contact hole 104b at this stage is Aluminum film 119 because it is relatively low
There is no problem in the step coverage with respect to the contact hole 104b of b. Of course, also in this embodiment, the aluminum film or the like can be formed after filling the contact hole 104b with the tungsten film or the like. In addition,
A titanium nitride film may be further formed on the surface of the aluminum film 119b. Instead of the aluminum film 119b, an aluminum alloy film such as an aluminum-silicon alloy film, an aluminum-silicon-copper alloy film, or an aluminum-germanium alloy film may be formed by high temperature sputtering.

Next, the aluminum film 1 is formed by RIE using a photoresist pattern (not shown) as a mask and boron trichloride gas and chlorine gas as etchant gases.
19b and the titanium nitride film 108b are patterned. As a result, the metal wiring 120 formed by laminating the titanium nitride film 108baa and the aluminum film 119ba.
b is formed [FIG.4 (c)].

The second embodiment has the effects of the first embodiment. Further, as described above, there is an effect associated with the fact that it is easy to make the effective aspect ratio of the contact hole lower than that in the first embodiment.

In the second embodiment, as in the first embodiment, the N ⁺ type diffusion layer formed on the P well surface, the N type silicon substrate, or the P ⁺ formed on the N well surface is also used. It can also be applied to contact holes reaching the mold diffusion layer and the like. In addition, bipolar, CMOS or BiCOM
It is also applicable to semiconductor devices such as. Further, similarly to the first embodiment, PECVD (HW-) by helicon wave is used for forming the titanium silicide film and the titanium nitride film.
PECVD equipment can also be used.

As an application of the second embodiment, it is possible to fill the contact hole 104b by selectively growing a tungsten film after forming the titanium silicide film 107b (see FIG. 4B).

The manufacturing method in this case is as follows. First, the silicon substrate 101 after forming a titanium silicide film 107b is taken out from the ECR-PECVD device, hydrogen peroxide (H ₂ O _2): ammonia (NH ₄ O
H): water = 1: 1: 5 to a solution of silicon substrate 10
Titanium silicide 10 by immersing 1 for about 5 minutes
The titanium film or titanium particles formed simultaneously with 7b are removed. Next, tungsten hexafluoride gas: monosilane gas: argon gas = 10 sccm: 6 sccm: 10
LPCVD under the conditions of a flow rate ratio of 0 sccm, a substrate temperature of 300 ° C. and a pressure of 2 Pa enables selective growth of a tungsten film on the surface of the titanium silicide film 107b. Here, since the tungsten film cannot be selectively grown only in the contact hole 104b after the titanium nitride film is formed, the tungsten film is formed without forming the titanium nitride film. Although the adhesion between the interlayer insulating film 103 and the tungsten film is not so good, since the tungsten film is formed only in the contact hole 104b,
There is no substantial obstacle.

[0053]

As described above, according to the method for manufacturing a semiconductor device of the present invention, the effective depth of the junction of the diffusion layer does not become shallow, and the impurity distribution of the diffusion layer does not change. It becomes easy to simultaneously suppress deterioration of leak resistance and increase of contact resistance. Further, it becomes easy to form a barrier metal layer on the bottom surface of the contact hole having a narrow aperture and a high aspect ratio.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a manufacturing process according to a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of the manufacturing process of the first embodiment.

FIG. 3 is a diagram for explaining the first embodiment,
6 is a graph showing the intensity distribution of the X-ray diffraction spectrum of the titanium silicide film according to this example.

FIG. 4 is a schematic cross-sectional view of the manufacturing process of the second embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view of a manufacturing process for explaining a conventional method for manufacturing a semiconductor device.

FIG. 6 is a cross-sectional schematic view for explaining another conventional method for manufacturing a semiconductor device.

[Explanation of symbols]

101 P-type silicon substrate 102 N ⁺ type diffusion layer 103, 303 Inter-layer insulating film 104a, 104b, 204, 304 Contact hole 105a, 105b, 205 Polycrystalline silicon film 107a, 107aa, 107b, 207, 307
Titanium silicide film 108a, 108aa, 108b, 108ba, 11
8, 118a, 208, 308 Titanium nitride film 109, 109a Tungsten film 116, 116a, 206, 306 Titanium film 119a, 119aa, 119b, 119ba Aluminum film 120a, 120b Metal wiring 201 N type semiconductor substrate 202 P ⁺ type diffusion layer 203 Insulating film 210 Gate electrode 219 Aluminum-silicon-copper alloy film 301 Silicon substrate 302 Diffusion layer

Claims (15)

(57) [Claims] 1. A step of forming an interlayer insulating film on a silicon substrate of one conductivity type having a diffusion layer of the opposite conductivity type on the surface, and forming a contact hole reaching the diffusion layer in the interlayer insulating film. A step of removing a natural oxide film on the surface of the diffusion layer exposed at the bottom surface of the contact hole and forming a polycrystalline or amorphous silicon film on the entire surface; And a plasma is generated to remove a natural oxide film on the surface of the silicon film, and a titanium tetrachloride gas, a hydrogen gas and a carrier gas are introduced into the plasma-enhanced chemical vapor deposition apparatus to form a plasma. To convert the silicon film into a titanium silicide film,
A step of further introducing nitrogen gas to generate plasma to form a titanium nitride film covering the surface of the titanium silicide film, and a step of forming a metal film covering the surface of the titanium nitride film. Forming a metal wiring connected to the diffusion layer through the contact hole by patterning a titanium film and the titanium silicide film. 2. The method for manufacturing a semiconductor device according to claim 1, wherein the silicon film is formed by a low pressure chemical vapor deposition method or a plasma enhanced chemical vapor deposition method. 3. The plasma-enhanced chemical vapor deposition apparatus comprises:
2. The method for manufacturing a semiconductor device according to claim 1, wherein the apparatus is a plasma-enhanced chemical vapor deposition apparatus using electron cyclotron resonance using microwaves or a plasma-excited chemical vapor deposition apparatus using helicon waves. 4. The removal of the natural oxide film on the surface of the silicon film in the plasma enhanced chemical vapor deposition apparatus is performed by introducing hydrogen gas and generating plasma. A method for manufacturing a semiconductor device as described above. 5. A step of forming an interlayer insulating film on a silicon substrate of one conductivity type having a diffusion layer of the opposite conductivity type on the surface, and forming a contact hole reaching the diffusion layer in the interlayer insulating film. A step of removing a natural oxide film on the surface of the diffusion layer exposed at the bottom surface of the contact hole and forming a polycrystalline or amorphous silicon film on the entire surface; And a plasma is generated to remove a natural oxide film on the surface of the silicon film, and a titanium tetrachloride gas, a hydrogen gas and a carrier gas are introduced into the plasma-enhanced chemical vapor deposition apparatus to form a plasma. To convert the silicon film into a titanium silicide film,
A step of further introducing nitrogen gas to generate plasma to form a titanium nitride film covering the surface of the titanium silicide film; and forming a first metal film covering the surface of the titanium nitride film,
Etching back at least the first metal film to leave the first metal film, the titanium nitride film, and the titanium silicide film in the contact hole; and the first metal film left in the contact hole. Forming a second metal film covering the surface of the interlayer insulating film including the surfaces of the metal film, the titanium nitride film and the titanium silicide film, and patterning at least the second metal film to form the contact hole. And a step of forming a metal wiring connected to the diffusion layer through the semiconductor device. 6. The method of manufacturing a semiconductor device according to claim 5, wherein the silicon film is formed by a low pressure chemical vapor deposition method or a plasma enhanced chemical vapor deposition method. 7. The plasma enhanced chemical vapor deposition apparatus comprises:
6. The method of manufacturing a semiconductor device according to claim 5, wherein the plasma-enhanced chemical vapor deposition apparatus by electron cyclotron resonance using microwaves or the plasma-enhanced chemical vapor deposition apparatus by helicon waves is used. 8. The removal of the natural oxide film on the surface of the silicon film in the plasma-enhanced chemical vapor deposition apparatus is carried out by introducing hydrogen gas and generating plasma. A method for manufacturing a semiconductor device as described above. 9. The method according to claim 5, wherein the first metal film is made of tungsten or tungsten silicide by a low pressure chemical vapor deposition method.
Alternatively, the method of manufacturing a semiconductor device according to claim 8. 10. A step of forming an interlayer insulating film on a silicon substrate of one conductivity type having a diffusion layer of the opposite conductivity type provided on the surface thereof, and forming a contact hole reaching the diffusion layer in the interlayer insulating film. A step of removing a natural oxide film on the surface of the diffusion layer exposed on the bottom surface of the contact hole and selectively forming a polycrystalline silicon film on the surface of the diffusion layer exposed on the bottom surface of the contact hole; A step of inserting the silicon substrate into an excited chemical vapor deposition apparatus and generating plasma to remove a natural oxide film on the surface of the polycrystalline silicon film; and a titanium tetrachloride gas inside the plasma enhanced chemical vapor deposition apparatus. And a hydrogen gas and a carrier gas are introduced, plasma is generated to convert the polycrystalline silicon film into a titanium silicide film, and nitrogen gas is additionally introduced to generate plasma to generate the titanium gas. Forming a titanium nitride film covering the surface of the contact hole and the surface of the interlayer insulating film including the surface of the silicide film, and forming a metal film covering the surface of the titanium nitride film. Forming a metal wiring connected to the diffusion layer through the contact hole by patterning a titanium nitride film. 11. The plasma-enhanced chemical vapor deposition apparatus is a plasma-excited chemical vapor deposition apparatus using electron cyclotron resonance using microwaves or a plasma-excited chemical vapor deposition apparatus using helicon waves. Item 11. A method for manufacturing a semiconductor device according to item 10. 12. The removal of the natural oxide film on the surface of the polycrystalline silicon film in the plasma-enhanced chemical vapor deposition apparatus is carried out by introducing hydrogen gas and generating plasma. Item 12. A method of manufacturing a semiconductor device according to item 11. 13. A step of forming an interlayer insulating film on a silicon substrate of one conductivity type having a diffusion layer of the opposite conductivity type on the surface, and forming a contact hole reaching the diffusion layer in the interlayer insulating film. A step of removing a natural oxide film on the surface of the diffusion layer exposed on the bottom surface of the contact hole and selectively forming a polycrystalline silicon film on the surface of the diffusion layer exposed on the bottom surface of the contact hole; A step of inserting the silicon substrate into an excited chemical vapor deposition apparatus and generating plasma to remove a natural oxide film on the surface of the polycrystalline silicon film; and a titanium tetrachloride gas inside the plasma enhanced chemical vapor deposition apparatus. And hydrogen gas and carrier gas are introduced to generate plasma to convert the polycrystalline silicon film into a titanium silicide film, and a tungsten film is selected in the contact hole. And forming a metal film covering the surface of the interlayer insulating film including the surface of the tungsten film formed in the contact hole, and patterning the metal film to form the metal film through the contact hole. And a step of forming a metal wiring connected to the diffusion layer. 14. The plasma-enhanced chemical vapor deposition apparatus is a plasma-excited chemical vapor deposition apparatus by electron cyclotron resonance using microwaves or a plasma-excited chemical vapor deposition apparatus by helicon waves. Item 14. A method of manufacturing a semiconductor device according to item 13. 15. The removal of the natural oxide film on the surface of the polycrystalline silicon film in the plasma-enhanced chemical vapor deposition apparatus is carried out by introducing hydrogen gas and generating plasma. Item 15. A method of manufacturing a semiconductor device according to item 14.