JP2003068673A - Semiconductor device and method of manufacturing the same - Google Patents

Abstract

[PROBLEMS] To provide a semiconductor device having high reliability and stable performance by preventing aggregation of a silicide layer and generation of voids in a wiring contact portion. Further, a contact resistance of a wiring layer is reduced, and a semiconductor device having good electric characteristics is obtained. A semiconductor layer including silicon, an interlayer insulating film having an opening formed on the semiconductor layer, and a wiring layer formed on the interlayer insulating film are provided. A tungsten-containing cobalt silicide layer is formed at the interface with the substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a manufacturing method thereof, and more particularly to a semiconductor device having a silicide layer in a wiring contact and a manufacturing method thereof.

[0002]

2. Description of the Related Art In response to the demand for higher integration of LSI, the size of a contact hole which is electrically connected to an element formed on a semiconductor substrate has been reduced as a semiconductor device has been miniaturized. In the 100nm generation VLSI,
Securing the stability of contact resistance in such contact holes has become more important. Further, with the miniaturization of wirings, in recent years, wirings using a refractory metal film such as tungsten have become necessary in order to keep wiring resistance low. When such wiring is used, a laminated film of Ti and TiN is often used as a barrier metal in the contact portion. However, there is a problem that the Ti silicide formed in contact with the silicon substrate is aggregated by high temperature heat treatment and the contact resistance is increased, which is becoming a big problem in future VLSI devices.

FIG. 8 is a schematic sectional view showing a conventional manufacturing process of a semiconductor device. Referring to FIG. 8A, the element isolation insulating film 10 made of a silicon oxide film is formed on the main surface of the semiconductor substrate 101 by using the shallow trench isolation method.
3 is formed to a thickness of 300 nm. After that, the impurity diffusion layer 105 is formed in a region to be an active region on the main surface of the semiconductor substrate 101 by an ion implantation method and a heat treatment.

Next, referring to FIG. 8B, an interlayer insulating film 107 having a thickness of 1 μm is formed on the semiconductor substrate 101 by the CVD method, and then the interlayer insulating film 107 is formed by the photolithography method and the etching method. The impurity diffusion layer 105
To form a contact hole 109 reaching to.

Next, referring to FIG. 8C, after cleaning the surface of the semiconductor substrate 101 with hydrofluoric acid or the like, the interlayer insulating film 107 including the inside of the contact hole 109 is formed by using a sputtering method or a CVD method. On the Ti film 111a and Ti
The N film 112a film is formed to a thickness of 20 nm and 50 nm, respectively. After that, C is further formed on the TiN film 112a.
By the VD method, the WF ₆ gas is used to remove the W film 113a.
It is formed to a thickness of 00 to 500 nm.

Next, referring to FIG. 8D, the W film 113
A desired resist pattern (not shown) is formed on a by a photolithography method, and the W film 113a, the TiN film 112a, and the Ti film 111a are etched using the resist pattern as a mask, whereby the Ti film 111 and the TiN film 11 are etched.
2 and the wiring layer 115 including the W film 113 is formed.
Here, the Ti film 111 and the TiN film 112 form the barrier metal 114.

When the Ti film 111a is formed by the CVD method, it is already silicidized immediately after the film formation. Further, when the Ti film 111a is formed by the sputtering method, it is silicidized by performing heat treatment before forming the W film 113a, for example, rapid thermal annealing or furnace annealing. of course,
These heat treatments may be performed after the barrier metal is formed by the CVD method.

[0008]

However, after the wiring layer 115 shown in FIG. 8D is formed, it is necessary to further perform a predetermined process until the final semiconductor device is completed. At this time, for example, in a process such as a densification of an interlayer insulating film further formed on the wiring layer 115 or a capacitor forming process in the case of DRAM, 800 ° C. to 9 ° C.
Various high temperature heat treatments at 00 ° C. are performed.

However, when the diameter of the contact hole becomes 100 nm and the aspect ratio becomes large, such a high temperature heat treatment causes T at the bottom of the contact as shown in FIG.
This may cause aggregation 117 of i-silicide, which may reduce the contact area and increase the contact resistance. Also,
Immediately before forming the Ti film, Ar sputter etching may be performed to remove the natural oxide film at the bottom of the contact. However, if such a treatment is performed, voids 119 may be generated in the Ti silicide, and the fine contact may be formed. This leads to a decrease in reliability of the element included.

The present invention has been made to solve the above problems. A first object of the present invention is to provide a highly reliable semiconductor device in which no agglomeration of silicide or voids is generated in a contact portion of a wiring. To do.

A second object is to reduce the contact resistance value of the wiring layer and provide a semiconductor device having good electric characteristics.

Furthermore, a third object is to provide a manufacturing method for obtaining the above semiconductor device.

[0013]

[Means for Solving the Problems] Formed on a semiconductor layer,
An interlayer insulating film having an opening reaching the semiconductor layer and a wiring layer formed on the interlayer insulating film and connected to the semiconductor layer,
The tungsten-containing cobalt silicide is formed at the interface between the semiconductor layer and the wiring layer in the opening.

The wiring layer includes a laminated film of a titanium nitride film and a tungsten wiring formed on the titanium nitride film.

The wiring layer includes a laminated film of a first tungsten film, a tungsten nitride film formed on the tungsten film, and a second tungsten wiring formed on the tungsten nitride film.

A step of forming an interlayer insulating film having an opening reaching the semiconductor layer on the semiconductor layer, a step of forming a tungsten-containing cobalt silicide layer on the semiconductor layer in the opening, and a tungsten-containing cobalt on the interlayer insulating film. And a step of forming a wiring layer connected to the semiconductor layer via a silicide layer.

In the step of forming the tungsten-containing cobalt silicide layer, a step of sequentially forming a cobalt film and a titanium nitride film on the interlayer insulating film including the inside of the opening and a first heat treatment are performed to react the semiconductor layer with the cobalt film. Step of forming a cobalt silicide layer on the semiconductor layer in the opening, step of removing unreacted cobalt film and titanium nitride film, and formation of a tungsten film on the interlayer insulating film including the opening so as to be in contact with the cobalt silicide layer The process and the second heat treatment include a process of reacting the tungsten film and the cobalt silicide layer and a process of removing the unreacted tungsten film.

Before the tungsten film is formed, a step of further performing a third heat treatment is included.

Before forming the cobalt film, a step of sputter etching the semiconductor layer exposed in the opening of the interlayer insulating film is included.

The first heat treatment is carried out in an atmosphere of low oxygen concentration of 5 ppm or less.

The step of forming the tungsten-containing cobalt silicide layer includes the step of selectively forming a tungsten film on the semiconductor layer in the opening, and the cobalt film and titanium nitride so as to contact the tungsten film on the interlayer insulating film including the inside of the opening. A step of sequentially forming the films, a step of reacting the tungsten film and the cobalt film by the first heat treatment to form the first tungsten-containing cobalt silicide layer, and a step of removing the unreacted cobalt film and titanium nitride film. And the second
The step of further heat-treating the first tungsten-containing cobalt silicide layer to form a second tungsten-containing cobalt silicide layer.

The first heat treatment is carried out in an atmosphere having a low oxygen concentration of 5 ppm or less.

In the step of forming the tungsten-containing cobalt silicide layer, the step of sequentially forming the cobalt film and the titanium nitride film on the interlayer insulating film including the inside of the opening and the first heat treatment are performed to react the semiconductor layer with the cobalt film. By the step of forming the cobalt silicide layer on the semiconductor layer in the opening, the step of removing the unreacted cobalt film and the titanium nitride film, the step of selectively forming the tungsten film on the cobalt silicide layer, and the second heat treatment, The step of reacting the tungsten film and the cobalt silicide layer is included.

By a step of forming an interlayer insulating film having an opening reaching the semiconductor layer on the semiconductor layer, a step of sequentially forming a cobalt film and a titanium nitride film on the interlayer insulating film including the inside of the opening, and a first heat treatment. , A step of reacting the semiconductor layer with the cobalt film to form a cobalt silicide layer on the semiconductor layer in the opening, a step of removing unreacted cobalt film and titanium nitride film, and cobalt on the interlayer insulating film including the inside of the opening. A step of forming a first tungsten film or a tungsten silicide film so as to be in contact with the silicide layer, and a step of forming the first tungsten film or the tungsten silicide film,
A step of sequentially forming a tungsten nitride film and a second tungsten film, and a step of forming a tungsten-containing cobalt silicide layer by reacting the first tungsten film or the tungsten silicide film with the cobalt silicide layer by a second heat treatment. A desired resist film is formed on the second tungsten film, and the second tungsten film, the titanium nitride film and the first tungsten film or the tungsten silicide film are sequentially etched using the resist film as a mask to form a wiring layer. And a step of performing.

The second heat treatment is performed immediately after the first tungsten film or the tungsten silicide film is formed.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. 1 to 3
FIG. 4 is a schematic cross-sectional view showing the manufacturing process of the semiconductor device according to the first embodiment of the present invention. In the explanatory diagrams used in each of the embodiments described below, the same or corresponding parts will be denoted by the same reference symbols and description thereof will be omitted.

Referring to FIG. 1A, a device isolation insulating film 3 made of a silicon oxide film is formed on the main surface of a semiconductor substrate 1 made of silicon by a shallow trench isolation method (STI: Shallow Trench Isolation). To 300
It is formed to a thickness of nm. After that, the impurity diffusion layer 5 is formed in a region to be an active region on the main surface of the semiconductor substrate 1 by an ion implantation method and a heat treatment.

Next, referring to FIG. 1B, an interlayer insulating film 7 having a thickness of 1 μm is formed on the semiconductor substrate 1 by the CVD method, and then the interlayer insulating film 7 is formed by the photolithography method and the etching method. A contact hole 9 reaching the impurity diffusion layer 5 is opened in the film 7.

Next, referring to FIG. 1C, after cleaning the surface of the semiconductor substrate 1 with a hydrofluoric acid solution or the like, a Co film is formed on the interlayer insulating film 7 including the contact holes 9 by a sputtering method. The (cobalt) film 11a and the TiN (titanium nitride) film 13a are respectively 20 nm to 100 nm and 5n.
The layers are sequentially formed with a thickness of m to 50 nm. The Co film 11
Immediately before forming a, sputter etching with Ar (argon) or Ne (neon) gas is performed using a sputtering device in order to remove the natural oxide film formed on the semiconductor substrate 1 at the bottom of the contact hole 9. May be.

Next, referring to FIG. 2A, the semiconductor substrate 1 is subjected to a low oxygen concentration of 5 ppm or less at a temperature of 400 ° C. to 550 ° C. and N ₂ (nitrogen) or Heat treatment is performed for 10 to 100 seconds in an atmosphere of an inert gas such as Ar or in vacuum. By this heat treatment, the Co film 11a and the silicon of the semiconductor substrate 1 react with each other to form a silicide, and thereafter, a mixed solution of hydrogen peroxide and sulfuric acid or hydrochloric acid adjusted to a temperature of 60 ° C. to 85 ° C. is used. By removing the reaction Co film 11a and TiN film 13a, the semiconductor substrate 1 in the contact hole 9 is removed.
A Co silicide layer 15 is selectively formed on the top.

Since the Co silicide layer 15 at this stage is formed by heat treatment at a low temperature, Co ₂ Si or Co is formed.
It has a composition of Si. By the heat treatment under the low oxygen concentration condition as described above, the oxygen concentration contained in the Co silicide layer is changed to SIMS (Secondary ion).
The content is below the detection limit of mass spectroscopy).

Next, referring to FIG. 2B, a W (tungsten) film 17 is formed on the interlayer insulating film 7 including the contact holes 9 by a sputtering method, and then 50
Heat treatment is performed at a temperature of 0 ° C. to 700 ° C. for 30 seconds to 120 seconds. As a result, the tungsten in the W film 17 becomes C
The W-containing Co silicide layer 19 is formed by thermal diffusion into the o silicide layer 15. Note that this heat treatment is performed in an atmosphere of low oxygen concentration in the same manner as the above heat treatment to prevent unnecessary oxygen from being mixed.

Next, with reference to FIG.
The unreacted W film 17 is removed using a mixed solution of hydrogen peroxide and sulfuric acid or hydrochloric acid adjusted to a temperature of 5 ° C. As a result, W-containing Co which is an alloy of Co with W and Si
The silicide 19 is selectively formed at the bottom of the contact hole 9. This alloy film has better heat resistance than the Ti silicide film, and can prevent agglomeration that has conventionally occurred due to heat treatment.

Before forming the W film 17, for example,
Heat treatment may be performed at a temperature of 550 ° C. to 700 ° C. to further promote silicidation between the semiconductor substrate 1 and the silicide layer 15, and a silicide film having a composition of CoSi ₂ may be formed. At this time, if sputter etching with Ar is performed before forming the Co film, Ar injected into the semiconductor substrate 1 diffuses outward and is released. In the case of Ti, when the silicide reaction proceeds, silicon in the semiconductor substrate 1 diffuses, so that the silicon moves to the Ti film side. as a result,
Ar injected into the semiconductor substrate 1 is left as it is,
Ti silicide is formed on the Ar injection layer. Therefore, Ar does not escape to the outside and a void is left in the semiconductor substrate.

On the other hand, when the reaction of Co silicide proceeds, since Co diffuses into the semiconductor substrate, Co diffuses downward from the Ar injection layer, and silicidation proceeds. That is, when the silicidation progresses and further CoSi ₂ having a high Si composition is formed, Ar diffuses outward and becomes a gas to escape from the semiconductor substrate. As a result, unlike the case of Ti, no void is formed in the semiconductor substrate.

Next, referring to FIG. 3, a TiN film having a thickness of 10 nm to 50 nm is formed on the interlayer insulating film 7 including the contact hole 9 by the CVD method or the sputtering method, and W is formed by the CVD method. The film is sequentially formed to have a thickness of 100 nm to 500 nm. Further, a desired resist pattern (not shown) is formed on the W film by a photolithography method, and the W film and the TiN film are etched by using the resist pattern as a mask to form a wiring composed of the W film 23 and the TiN film 21 as a barrier metal. Form layer 25. As a barrier metal, 3 below the TiN film 21 is used.
A Ti film with a thickness of 10 nm to 10 nm may be formed. After that, a desired semiconductor device is formed through a predetermined process.

As described above, according to the invention according to the first embodiment, the Co silicide layer containing W is formed at the contact interface between the wiring layer and the semiconductor substrate made of silicon, so that the subsequent heat treatment can be performed. Since the silicide layer does not agglomerate and voids do not occur, the increase in contact resistance is suppressed, and a highly reliable and stable semiconductor device can be obtained.

Embodiment 2. In the first embodiment, the W film is formed on the Co silicide layer by the sputtering method, and after the W is mixed into the Co silicide layer by the heat treatment, the W film is removed. On the other hand, in the present embodiment, a W film is selectively formed, and then a Co silicide layer is formed on this W film and heat treatment is performed to mix W.
FIG. 4 is a schematic cross-sectional view showing the manufacturing process of the semiconductor device according to the embodiment of the present invention.

First, according to the steps shown in FIGS. 1A and 1B of the first embodiment, contact hole 9 is formed on semiconductor substrate 1 to reach impurity diffusion layer 5 formed in the substrate.
Up to the interlayer insulating film 7 having

Next, referring to FIG. 4A, the semiconductor substrate 1 is formed on the semiconductor substrate 1 by the CVD method at a temperature of 250 ° C. to 450 ° C. using a mixed gas of WF ₆ and H ₂ or SiH _4. With a thickness of 5 nm to 10 nm at the bottom of the contact hole 9 of
The film 17 is selectively formed.

Next, referring to FIG. 4 (b), the inter-layer insulation film 7 including the contact holes 9 is sputtered.
The Co film 11a and the TiN film 13a each have a thickness of 20n.
It is formed to have a thickness of m to 100 nm and 5 nm to 50 nm.

Next, referring to FIG. 4 (c), the semiconductor substrate 1 is heated to a temperature of 400 ° C. to 550 ° C. under a low oxygen concentration of 5 ppm or less and is not exposed to N2 or Ar. 10 seconds ~ in active gas atmosphere or vacuum
Heat treatment is performed for 100 seconds. By this heat treatment, the Co film 11a and the W film 17 react with each other, and the Co film 11a
And the silicon of the semiconductor substrate 1 undergoes a silicide reaction to form the first W-containing Co silicide layer 19 on the surface of the semiconductor substrate 1 at the bottom of the contact hole.

Under the above temperature conditions (400 ° C. to 55 ° C.)
At 0 ° C., since the silicide reaction between the W film 17 and silicon of the semiconductor substrate 1 is slow, the consumption of silicon due to the reaction between W and silicon is suppressed, and W is mixed in the Co silicide film.

Next, with reference to FIG.
The unreacted Co film 11a and TiN film 13a are removed using a mixed solution of hydrogen peroxide and sulfuric acid or hydrochloric acid adjusted to a temperature of 5 ° C. Only the W-containing Co silicide film 19 is left selectively. Then, on the semiconductor substrate 1, 550 ° C. to 7 ° C.
A heat treatment at 00 ° C. is performed to further promote the silicide reaction of Co to form the second W-containing Co silicide film 19.
Reduce resistance.

Then, according to the process of FIG. 3 of the first embodiment, the W film 23 and the TiN film 21 as the barrier metal are formed.
Then, the wiring layer 25 is formed. After that, a desired semiconductor device is completed through a predetermined process.

As described above, according to the invention of this embodiment, the aggregation of the silicide layer and the generation of voids are suppressed, and W is selectively formed, so that the step of removing the W film can be omitted. The manufacturing process of the semiconductor device can be shortened.

Embodiment 3. In the second embodiment, a W film is selectively formed, and then a Co film is formed on the W film and heat-treated to mix W, but in the present embodiment, a Co silicide layer is formed. Then, the W film is selectively formed. Hereinafter, it will be described in detail with reference to the schematic cross-sectional views showing the manufacturing process of the semiconductor device shown in FIG. First, the Co silicide layer 15 is formed at the bottom of the contact hole 9 according to the steps of FIGS. 1 to 2A of the first embodiment.

Next, referring to FIG. 5A, a mixed gas of WF ₆ gas and H ₂ gas or SiH ₄ gas is formed on the Co silicide layer 15 by the CVD method at 250 ° C.
Under the temperature condition of ˜450 ° C., the W film 17 has a thickness of 5 nm to 10 n.
It is selectively formed to a thickness of m. In this case, the W film 17 is C
Since it is formed on the silicide layer 15, the semiconductor substrate 1
It is possible to suppress the reaction between the silicon and the WF ₆ gas, and to prevent the destruction of the junction such as the impurity diffusion layer formed on the semiconductor substrate 1.

Next, referring to FIG. 5B, the semiconductor substrate 1 is heat-treated at a temperature of 550 ° C. to 700 ° C.
Of the W film 17 and tungsten of the W film 17 are diffused into the Co silicide layer.
A silicide film 19 is formed.

Then, according to the process of FIG. 3 of the first embodiment, the W layer 23 and the TiN layer 21 as a barrier metal are formed.
Then, the wiring layer 25 is formed. After that, a desired semiconductor device is completed through a predetermined process.

As described above, according to the invention of this embodiment, the aggregation of the silicide layer and the generation of voids are suppressed, and the reaction between the silicon of the semiconductor substrate and the WF ₆ gas is suppressed during the formation of the W film. Since it is suppressed, it is possible to prevent the junction formed on the semiconductor substrate from being broken, and it is possible to manufacture a highly reliable semiconductor device. Further, since W is selectively formed, the step of removing the W film can be omitted and the manufacturing process of the semiconductor device can be shortened.

Fourth Embodiment In the second and third embodiments, the manufacturing process is shortened by using the selective formation method of the W film, but in the present embodiment, a method of shortening the manufacturing process without using the selection method will be described. First, according to the steps of FIG. 1 to FIG. 2A of the first embodiment, the Co silicide layer 15 is formed at the bottom of the contact hole 9.

Next, referring to FIG. 6A, the interlayer insulating film 7 including the contact holes 9 is sputtered by a sputtering method.
The first W film 27a is formed with a thickness of 10 nm to 20 nm. After that, a WN (tungsten nitride) film 29a is formed to a thickness of 10 nm to 50 nm on the first W film 27a by a sputtering method or a CVD method. After that,
The second W film 31a is formed on the WN film 29a by the CVD method.
To a thickness of 100 nm to 500 nm.

Next, referring to FIG. 6B, a predetermined heat treatment (for example, densification heat treatment of the interlayer insulating film) is performed to cause the W film 27a and the Co silicide layer 15 to react with each other. , W-containing Co silicide layer 19 is formed.
Immediately after forming the first W film 27a, for example, 6
Heat treatment is performed at 00 ° C to 800 ° C to obtain W, Co and Si.
The W-containing Co silicide layer 19 made of an alloy of

Next, referring to FIG. 6C, the second W film 31a, the WN film 29a, and the first W film 31a and the first W film 31a are masked with a desired resist pattern (not shown) formed on the second W film 31a. By sequentially etching the W film 27a, the first W film 27 and the WN film 29 as a barrier metal,
A wiring layer 33 made of the second W film 31 is formed. After that, a semiconductor device is completed through a predetermined process.

As described above, according to the invention of the present embodiment, the aggregation of the silicide layer and the generation of voids are suppressed, and since the W film is used as the barrier metal of the wiring layer, tungsten is used as the Co silicide film. Since it is not necessary to provide a special W film process for containing the element, the manufacturing process is shortened. Further, since the wiring layers are made of the same material containing W as the main material, the controllability of etching is improved.

Embodiment 5. In the fourth embodiment, the W film is used as the film in contact with the Co silicide layer 15, but in the present embodiment, this is the W silicide film. Hereinafter, description will be given with reference to sectional views of manufacturing steps of the semiconductor device shown in FIG. First, similar to the fourth embodiment, the Co silicide layer 1 is formed on the semiconductor substrate 1 at the bottom of the contact hole 9 according to the steps shown in FIGS. 1 to 2A of the first embodiment.
Form up to 5.

Next, referring to FIG. 7A, W is formed on the interlayer insulating film 7 including the contact hole 9 by the CVD method.
Using a mixed gas of F ₆ gas and SiH ₂ Cl ₂ gas or SiH ₄ gas, WSi _X (W silicide: X = 1.
5 to 2.5) The film 35a is formed.

After that, a WN film 37a is formed on the WSi _X film 35a by a CVD method or a sputtering method, and a W film 39a is further formed thereon by a CVD method. Next, referring to FIG. 7B, a predetermined heat treatment (for example, a heat treatment for densifying the interlayer insulating film) is performed thereafter, whereby the Co silicide layer 15 and the W silicide film 35a react with each other and W The contained Co silicide layer 19 is formed.

Next, referring to FIG. 7C, the W film 39a
The W film 39a, the WN film 37a, and the W silicide film 35a are etched by using a desired resist pattern (not shown) formed above as a mask, so that the W film 39 and the WN film 37 and the W silicide film 35 as the barrier metal are formed.
A wiring layer 41 made of is formed. After that, a semiconductor device is completed through a predetermined process. After forming the WSi _X film a, heat treatment is performed at 600 ° C. to 800 ° C., for example, and W-containing Co made of an alloy with W, Co and Si is formed.
The silicide layer 19 may be used.

As described above, according to the invention of this embodiment, according to the invention of this embodiment, the aggregation of the silicide layer and the generation of voids are suppressed and the barrier metal of the wiring layer is used. Since the W silicide film is used, it is not necessary to provide a special W film process for containing tungsten in the Co silicide film, so that the manufacturing process is shortened. Moreover, since the wiring layers are made of the same material containing W as the main material, etching is facilitated. Furthermore, since the WSix film has better adhesion to the interlayer insulating film than the W film, it is possible to manufacture a semiconductor device having higher heat resistance.

[0062]

Since the present invention is constructed as described above, it has the following effects. According to the invention of claim 1, since the W-containing Co silicide layer is formed in the contact portion of the wiring layer, there is no aggregation of silicide, and a void-free semiconductor device having high reliability and stable performance. Can be obtained.

Further, according to the second aspect of the invention, since the wiring layer is made of the laminated film of the titanium nitride film and the tungsten film, the wiring layer having a low resistance can be obtained.

According to the third aspect of the present invention, the wiring layer includes the first tungsten film, the tungsten nitride film formed on the first tungsten film, and the second tungsten film formed on the first tungsten film. Since it is made of a laminated film, a wiring layer having lower resistance can be obtained.

Further, according to the invention of claim 4, since the W-containing Co silicide layer is formed at the interface between the semiconductor layer and the wiring layer, aggregation of the silicide and generation of voids are prevented and the semiconductor device is highly reliable. Can be manufactured.

Further, according to the invention of claim 5, it is possible to manufacture a highly reliable semiconductor device which is free from aggregation of silicide and generation of voids with high accuracy and reproducibility.

According to the invention of claim 6, a more stable wiring layer can be obtained.

According to the invention of claim 7, a wiring layer having a low resistance can be obtained.

According to the invention of claim 8, Co silicide having a stable film quality can be obtained.

According to the ninth aspect of the invention, since the step of removing the tungsten film is unnecessary, the manufacturing process of the semiconductor device can be shortened.

According to the tenth aspect of the invention, Co silicide having a stable film quality can be obtained.

According to the eleventh aspect of the invention, it is possible to prevent the breakage of the junction when selectively forming tungsten.

According to the twelfth aspect of the invention, the manufacturing process can be shortened and the etching for forming the wiring layer can be facilitated.

According to the thirteenth aspect of the invention, since the tungsten silicide film has good adhesion to the interlayer insulating film, a wiring layer having higher heat resistance can be obtained.

[Brief description of drawings]

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

FIG. 2 is a schematic cross sectional view showing a manufacturing process of the semiconductor device according to the first embodiment of the present invention.

FIG. 3 is a schematic cross sectional view showing the manufacturing process of the semiconductor device according to the first embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view showing the manufacturing process of the semiconductor device according to the second embodiment of the present invention.

FIG. 5 is a schematic cross sectional view showing a manufacturing process of the semiconductor device according to the third embodiment of the present invention.

FIG. 6 is a schematic cross sectional view showing a manufacturing process of the semiconductor device according to the fourth embodiment of the present invention.

FIG. 7 is a schematic cross-sectional view showing the manufacturing process of the semiconductor device according to the fifth embodiment of the present invention.

FIG. 8 is a schematic cross-sectional view showing a manufacturing process of a conventional semiconductor device.

FIG. 9 is a schematic cross-sectional view of a semiconductor device for explaining a conventional problem.

[Explanation of symbols]

1. Semiconductor substrate 7. Interlayer insulation film 9. Contact hole 11a. Co film 13a. TiN film 15. Co silicide layer 17a. W film 17. Select W film 19. W-containing Co silicide layer 21. TiN film 23. W film 27a. First W film 29a. WN film 31a. Second W film 33. Wiring layer 35a. Wsi film 37a. WN film 39a. W film 41. Wiring layer

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4M104 AA01 BB20 BB28 DD02 DD23                       DD43 DD46 DD78 DD84 FF13                       FF22 HH08 HH16                 5F033 HH18 HH19 HH28 HH33 HH34                       JJ18 JJ19 JJ25 JJ28 JJ33                       JJ34 KK01 MM05 MM08 MM13                       NN06 NN07 PP06 PP07 PP15                       QQ08 QQ09 QQ14 QQ19 QQ37                       QQ70 QQ73 QQ92 QQ94 WW04                       XX09 XX14

Claims (13)

[Claims] 1. A semiconductor layer containing silicon, an interlayer insulating film formed on the semiconductor layer and having an opening reaching the semiconductor layer, and formed on the interlayer insulating film and connected to the semiconductor layer. A semiconductor device comprising a wiring layer, wherein a tungsten-containing cobalt silicide layer is formed at an interface between the semiconductor layer and the wiring layer in the opening. 2. The semiconductor device according to claim 1, wherein the wiring layer includes a laminated film of a titanium nitride film and a tungsten film formed on the titanium nitride film. 3. The wiring layer includes a laminated film of a first tungsten film, a tungsten nitride film formed on the first tungsten film, and a second tungsten film formed on the tungsten nitride film. The semiconductor device according to claim 1. 4. A step of forming an interlayer insulating film having an opening reaching the semiconductor layer on a semiconductor layer containing silicon, and a step of forming a tungsten-containing cobalt silicide layer on the semiconductor layer in the opening. Forming a wiring layer connected to the semiconductor layer via the tungsten-containing cobalt silicide layer on the interlayer insulating film. 5. The step of forming the tungsten-containing cobalt silicide layer comprises the steps of sequentially forming a cobalt film and a titanium nitride film on the interlayer insulating film including the inside of the opening, and the first heat treatment to form the semiconductor layer and the cobalt film. To form a cobalt silicide layer on the semiconductor layer in the opening, to remove the unreacted cobalt film and the titanium nitride film, and on the interlayer insulating film including in the opening. The method includes a step of forming a tungsten film in contact with the cobalt silicide layer, a step of reacting the tungsten film with the cobalt silicide layer by a second heat treatment, and a step of removing the unreacted tungsten film. The method for manufacturing a semiconductor device according to claim 4. 6. The method of manufacturing a semiconductor device according to claim 5, further comprising a step of performing a third heat treatment before forming the tungsten film. 7. The method of manufacturing a semiconductor device according to claim 6, further comprising the step of sputter etching the semiconductor layer exposed in the opening of the interlayer insulating film before forming the cobalt film. 8. The method of manufacturing a semiconductor device according to claim 4, wherein the first heat treatment is performed in an atmosphere having a low oxygen concentration of 5 ppm or less. 9. The step of forming a tungsten-containing cobalt silicide layer includes the step of selectively forming a tungsten film on the semiconductor layer in the opening, and the step of contacting the tungsten film on the interlayer insulating film including the inside of the opening. A step of sequentially forming a cobalt film and a titanium nitride film on the substrate, a step of reacting the tungsten film with the cobalt film by a first heat treatment to form a first tungsten-containing cobalt silicide layer, A step of removing the cobalt film and the titanium nitride film, and a step of further silicifying the first tungsten-containing cobalt silicide layer by a second heat treatment to form a second tungsten-containing cobalt silicide layer. Item 5. A method of manufacturing a semiconductor device according to item 4. 10. The first heat treatment has an oxygen concentration of 5 ppm.
10. The method for manufacturing a semiconductor device according to claim 9, wherein the method is performed in the following atmosphere of low oxygen concentration. 11. The step of forming a tungsten-containing cobalt silicide layer comprises: a step of sequentially forming a cobalt film and a titanium nitride film on an interlayer insulating film including the inside of the opening; and a semiconductor layer and the cobalt film by a first heat treatment. To form a cobalt silicide layer on the semiconductor layer in the opening, removing the unreacted cobalt film and the titanium nitride film, and selectively forming a tungsten film on the cobalt silicide layer. 5. The method of manufacturing a semiconductor device according to claim 4, further comprising: a step of forming the tungsten film and a step of reacting the tungsten film with the cobalt silicide layer by a second heat treatment. 12. A step of forming an interlayer insulating film having an opening reaching the semiconductor layer on the semiconductor layer, and a step of sequentially forming a cobalt film and a titanium nitride film on the interlayer insulating film including the inside of the opening. A step of reacting the semiconductor layer with the cobalt film by a first heat treatment to form a cobalt silicide layer on the semiconductor layer in the opening, and a step of removing the unreacted cobalt film and titanium nitride film And a step of forming a first tungsten film or a tungsten silicide film on the interlayer insulating film including the inside of the opening so as to be in contact with the cobalt silicide layer; A step of sequentially forming a tungsten film and a second tungsten film, and a second heat treatment are performed to form the first tungsten film or the second tungsten film. Forming a tungsten-containing cobalt silicide layer by reacting the tungsten silicide film with the cobalt silicide layer, forming a desired resist film on the second tungsten film, and using the resist film as a mask. And a step of forming a wiring layer by sequentially etching the tungsten film, the titanium nitride film, and the first tungsten film or the tungsten silicide film of 2. 13. The method of manufacturing a semiconductor device according to claim 12, wherein the second heat treatment is performed immediately after the first tungsten film or the tungsten silicide film is formed.