JPH09186105A - Semiconductor device manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid overgrowth and deteriorating the characteristic of an element due to a high temp. heat treatment by forming a first high m.p. metal film on the surface of Si and second N-contained high m.p. metal film thereon and doing the heat treatment in an atmosphere contg. no N atom. SOLUTION: A N-contained second high m.p. metal film 108 is formed on a first Ti or other high m.p. metal film 107 formed on a Si substrate 101 and heat treated in an atmosphere contg. no N to form a silicide layer 109 by the silicidization whereby on the film 103 formed on the substrate 101 N from the second film 108 is diffused in the first film 107 to the nitrification of the high m.p. metal film and diffused Si reacts with the high m.p. metal to result the suppression of the overgrowth.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of forming a refractory metal silicide layer in a self-aligned manner on the surface of a diffusion layer of a semiconductor substrate or a polysilicon electrode.

[0002]

2. Description of the Related Art With the miniaturization and high density of semiconductor elements,
Currently, ultra-highly integrated semiconductor devices such as memory devices and logic devices designed on the basis of a size of 0.15 to 0.25 μm are provided. As such a semiconductor device is highly integrated, it is required to reduce the gate electrode length, the diffusion layer width, and the film thickness thereof. However,
These gate electrode length, diffusion layer width reduction and film thickness reduction are
Inevitably, it causes an increase in these electric resistances, which greatly affects the delay of the circuit. Therefore, in the miniaturized element, a silicide layer is formed in the surface region of the gate electrode formed of polysilicon or the diffusion layer of the single crystal silicon substrate to reduce the resistance. This silicide layer is formed by a salicide technique in which a silicide layer using a refractory metal is formed by self-alignment.

17 and 18 are sectional views showing an example of a method of manufacturing such a silicide layer in the order of steps. First, as shown in FIG. 17A, the element isolation insulating film 102 is formed in a predetermined region of the silicon substrate 101 by the LOCOS method. Impurities for channel stopper are ion-implanted into the element region of the silicon substrate 101, and the gate insulating film 103 is formed thereon by thermal oxidation. Then, a polysilicon film having a thickness of about 150 nm is formed on the entire surface by the CVD method, and impurities such as phosphorus are doped to reduce the resistance. After that, pattern formation is performed by the photolithography technique to form the gate electrode 104. Then, a silicon oxide film is deposited on the entire surface by the CVD method, and the silicon oxide film is etched by anisotropic etching to form the spacer 105 on the side surface of the gate electrode 104. Then, the silicon substrate 101
Impurities such as arsenic and boron are ion-implanted to
Diffusion layers 106 as source / drain regions are formed by heat treatment at 00 to 1000 ° C.

Next, as shown in FIG. 17B, a titanium film 107 having a thickness of about 50 nm is formed on the entire surface by a sputtering method. Then, heat treatment is carried out at a temperature of 600 to 650 ° C. for 30 seconds to 60 seconds using a lamp annealing device or the like in a nitrogen atmosphere at atmospheric pressure. As a result, nitrogen is diffused in the titanium film 107 to become a titanium nitride film 108, and a silicidation reaction is performed in a region in contact with silicon such as the gate electrode 104 and the diffusion layer 106, as shown in FIG. 17C. And the titanium silicide layer 1 on the interface
09 is formed. This titanium silicide layer 109 is
C4 with a crystal structure with a high electrical resistivity of about 60 μΩ · cm
It is a 9-structure titanium silicide layer.

After that, as shown in FIG. 18A, the titanium nitride film 108 which is not silicidized is removed by etching with a chemical liquid mixture of an aqueous ammonia solution and a hydrogen peroxide solution. As a result, only the titanium silicide layer 109 is left on the surface of silicon. Further, when the second heat treatment at about 850 ° C. is performed for about 60 seconds in a nitrogen atmosphere at atmospheric pressure, the titanium silicide layer 109 having the C49 structure described above has an electrical conductivity of about 20 μΩ · cm as shown in FIG. 18B. It can be changed to a titanium silicide layer 111 having a C54 structure having a low resistivity crystalline structure.

The reason why the titanium silicide layer 109 is formed in a nitrogen atmosphere is as follows. In the silicide reaction of titanium and silicon, the diffusion species is silicon. Here, silicon is diffused also on the oxide film such as the element isolation insulating film 102, and when the silicon diffused on the oxide film reacts with titanium, a titanium silicide layer is formed also on the oxide film. As a result, insulation due to the oxide film becomes defective and so-called overgrowth occurs. In order to prevent this, heat treatment is performed in a nitrogen atmosphere so that titanium reacts with nitrogen to form titanium nitride. Since the reaction temperature of this titanium nitride is lower than the silicide reaction temperature, the titanium on the oxide film is consumed in the film formation of titanium nitride, does not react with silicon, and the above titanium silicide layer is not formed. This allows the titanium silicide layer to be formed in a self-aligned manner only in the silicon region.

As a manufacturing method for promoting the formation of the titanium silicide layer which prevents such overgrowth,
For example, it is possible to use the technique described in Japanese Patent Laid-Open No. 3-73533. This manufacturing method is shown in FIG.
Similar to the process described in FIG. 19A, after the element isolation insulating film 102, the gate oxide film 103, the gate electrode 104, and the stopper 105 are formed on the silicon substrate 101, as shown in FIG. ), A titanium film 107 having a thickness of about 20 nm and a titanium nitride film 108 are formed in a stacked state on the entire surface. Then, heat treatment is performed in a nitrogen atmosphere, and the silicon and titanium films 107 are formed as shown in FIG.
A titanium silicide layer 109 is formed at the interface with. After that, as shown in FIGS. 20A and 20B, the titanium nitride film 108 and the titanium film 107 containing nitrogen are removed, and a second heat treatment is performed to change the C49 structure to the C54 structure titanium silicide layer. By changing to 111, a titanium silicide layer is formed.

In the manufacturing method described in this publication, the titanium nitride film 108 is present on the titanium film 107,
Since heat treatment is performed in a nitrogen atmosphere on top of that, there is an advantage that titanium oxide is not formed on the surface of the titanium film 107, and the layer resistance can be reduced. It becomes easier to supply nitrogen from the titanium nitride film 108, and it becomes possible to effectively prevent the above-mentioned overgrowth.

[0009]

The conventional manufacturing method as described above is effective in forming the titanium silicide layer in a self-aligned manner, but the titanium silicide layer is made thinner as the semiconductor device becomes finer. In that case, there is a problem that the titanium silicide layer may not be manufactured appropriately. That is, with the miniaturization of semiconductor devices, it is required to reduce the thickness of the titanium film for forming the titanium silicide layer. Here, if the titanium film is thinned, the nitriding reaction and the silicide reaction in titanium are likely to compete with each other. Especially,
When arsenic impurities are present in silicon, the silicide reaction rate is reduced and the nitriding reaction is relatively increased.
As a result, the thickness of the silicide layer is extremely reduced. In some cases, titanium is entirely consumed in the nitriding reaction, and the silicide layer may not be formed.

When the titanium silicide layer is formed in a nitrogen atmosphere, it is necessary to consider the effect on the phase transition required for the silicide process. That is, FIG. 21 shows the titanium film thickness dependence of the structural phase transition temperature from the C49 structure to the C54 structure. As you can see from the figure, 30n
With a film thickness of m or less, the nitrogen concentration in titanium increases due to the nitriding reaction, and the phase transition temperature rises. Therefore, after the titanium silicide layer is formed, the second heat treatment temperature for lowering the resistance is raised, and the diffusion layers such as the source / drain regions already formed by this high temperature treatment are affected. And cause deterioration of device characteristics. It also reduces the temperature margin with the agglomeration reaction of the silicide layer.

It is an object of the present invention to prevent overgrowth while enabling the formation of a refractory metal silicide layer on a fine element and preventing deterioration of element characteristics due to high temperature heat treatment. It is to provide a manufacturing method of.

[0012]

According to a method of manufacturing a semiconductor device of the present invention, a first refractory metal film is deposited on a silicon surface, and a second refractory metal containing the same material and containing nitrogen is deposited on the first refractory metal film. The method includes a step of forming a film and heat-treating the film to form a refractory metal silicide layer at the interface between silicon and the first refractory metal film, and this heat treatment is performed in an atmosphere containing no nitrogen atom. It is characterized by Further, in the present invention, a step of introducing nitrogen into the first refractory metal film by ion implantation can be adopted as the formation of the second refractory metal film. Here, in the present invention, the following forms can be adopted. That is, the formation of the first refractory metal film, the formation of the second refractory metal film containing nitrogen, and the heat treatment are performed in the same apparatus in an inert gas atmosphere or a vacuum atmosphere. After depositing the first refractory metal film, an oxide film of the refractory metal is formed on the first refractory metal film, and a second refractory metal film containing nitrogen is formed thereon. To form
And heat treatment is performed. Alternatively, after the first refractory metal film is deposited, or after the second refractory metal film containing nitrogen is formed, heat treatment is performed in an atmosphere containing hydrogen so that the first refractory metal film contains hydrogen. It is transformed into a melting point metal film, and heat treatment is performed thereon.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. 1 and 2 are sectional views showing a first embodiment of the present invention in the order of steps. First, FIG.
As shown in (a), the element isolation insulating film 102 is formed by a LOCOS method in a predetermined region of the silicon substrate 101 in which the P conductivity type or the P well is formed. Impurities for channel stoppers are ion-implanted into the element region of the silicon substrate 101, and a film thickness of 8 nm is formed thereon by thermal oxidation.
The gate insulating film 103 is formed to some extent.

Next, a film thickness of 100 is formed on the entire surface by the CVD method.
A polysilicon film of about nm is formed, and impurities such as phosphorus are doped to reduce the resistance. After that, pattern formation is performed by the photolithography technique to form the gate electrode 104. Then, the film thickness is 1 on the entire surface by the CVD method.
A spacer 105 is formed on the side surface of the gate electrode 104 by depositing a silicon oxide film of about 00 nm and etching the silicon oxide film by anisotropic etching. Then, impurities such as arsenic and boron are ion-implanted into the silicon substrate 101, and the diffusion layer 10 as a source / drain region is subjected to heat treatment at about 900 temperature.
6 are formed. Here, the dose of arsenic ions is 1 ×
It is set to about 10 ¹⁵ ions / cm ² .

Next, as shown in FIG. 1B, a titanium film 107 having a film thickness of about 20 nm is formed on the entire surface by a sputtering method, and a titanium nitride film 108 having a thickness of 50 nm is further formed thereon.
It is formed to have a film thickness of about. Then, heat treatment is performed in an argon atmosphere at 700 ° C. for 30 seconds using a lamp annealing device or the like. As a result, the titanium film 107 undergoes a silicidation reaction in a region in contact with silicon such as the gate electrode 104 and the diffusion layer 106, and the titanium silicide layer 109 having a C49 structure is formed at the interface as shown in FIG.
Is formed.

At this time, since the titanium nitride film 108 is present on the titanium film 107 on the oxide film 102 constituting the element isolation insulating film, nitrogen from the titanium nitride film 108 is removed from the titanium film 107 during the heat treatment. Nitrogen-containing titanium 110 is formed on the upper surface side of the titanium film 107 by diffusion to the titanium film 107, the titanium nitriding reaction in the titanium film 107 is promoted, and the diffused silicon and titanium are oxidized.
Overgrowth due to the above reaction is suppressed.

Further, FIG. 3 shows the titanium nitride film 10 after the argon heat treatment on the oxide film and the heat treatment in the nitrogen atmosphere.
8 and the depth distribution of nitrogen atoms in the titanium film 107 are shown. In the heat treatment in the argon atmosphere, nitrogen is not supplied from the atmosphere, so that nitrogen is diffused into the titanium film 107, while the nitrogen concentration in the titanium nitride film 108 is reduced. Further, in the heat treatment in the argon atmosphere, the diffusion depth of nitrogen into the titanium film 107 is shallower than that in the heat treatment in the nitrogen atmosphere. By suppressing the diffusion of nitrogen in the titanium film 107 in this way, the nitriding reaction of titanium in the region on the lower surface side where the titanium film 107 is in contact with silicon is suppressed.
Therefore, even when the film thickness of the titanium film 107 is reduced due to the miniaturization of the element, the silicide reaction due to the required amount of titanium is secured in the contact region with silicon, and a silicide layer having a suitable thickness is formed. It

Thereafter, as shown in FIG. 2A, the titanium nitride film 108 and the nitrogen-containing titanium film 110 are removed by etching with a chemical solution in which an aqueous ammonia solution and a hydrogen peroxide solution are mixed. As a result, only the titanium silicide layer 109 is left on the surface of silicon such as the gate electrode 104 and the diffusion layer 106. After that, when a second heat treatment at about 800 ° C. is performed for 10 seconds in an argon atmosphere, the titanium silicide layer 109 having the C49 structure is changed to the titanium silicide layer 111 having the C54 structure as shown in FIG. 2B.

At this time, the dependency of the phase transition temperature on the titanium film thickness is shown in FIG. 4 by performing the argon heat treatment, and there is no increase in the phase transition temperature especially when the titanium film thickness is reduced. The phase transition temperature can be lowered as compared with the characteristics in the case of the nitrogen atmosphere of No. 21. Therefore, C4
The processing temperature for changing the 9-structured silicide layer to the C54-structured silicide layer can be lowered as compared with the case of the nitrogen atmosphere as described above, and the characteristic deterioration of the element such as the MOS transistor due to the high temperature processing can be prevented.

5 and 6 are sectional views showing a second embodiment of the present invention in the order of manufacturing steps. First, as shown in FIG. 5A, an element isolation insulating film 102 is formed by a LOCOS method in a predetermined region of a silicon substrate 101 in which a P conductivity type or a P well is formed. In addition, the silicon substrate 101
An impurity for a channel stopper is ion-implanted into the element region, and a gate insulating film 103 having a film thickness of about 8 nm is formed thereon by a thermal oxidation method.

Next, a film thickness of 100 is formed on the entire surface by the CVD method.
A polysilicon film of about nm is formed, and impurities such as phosphorus are doped to reduce the resistance. After that, pattern formation is performed by the photolithography technique to form the gate electrode 104. Then, the film thickness is 100n by the CVD method.
A silicon oxide film is deposited on the entire surface of about m, and the silicon oxide film is etched by anisotropic etching to form a spacer 105 on the side surface of the gate electrode 104. Then, impurities such as arsenic and boron are ion-implanted into the silicon substrate 101, and the diffusion layer 10 as a source / drain region is subjected to heat treatment at about 900 temperature.
6 are formed. Here, the dose of arsenic ions is 1 ×
It is set to about 10 ¹⁵ ions / cm ² .

Next, as shown in FIG. 5B, a titanium film 107 having a thickness of about 20 nm is formed on the entire surface by the sputtering method. Then, as shown in FIG. 5C, nitrogen atoms are implanted into the titanium film 107. Nitrogen injection is 1
It is performed at an energy of about 50 KeV at × 10 ¹⁵ ions / cm ² . After that, heat treatment is performed at 700 ° C. for 30 seconds using a lamp annealing device or the like in an argon atmosphere.
As a result, the injected nitrogen is diffused in the titanium film 107 to become the nitrogen-containing titanium film 110, and the gate electrode 1 is formed on the lower surface of the titanium film 110 as shown in FIG. 6A.
04, the diffusion layer 106, and other regions in contact with silicon undergo a silicidation reaction, and a titanium silicide layer 109 having a C49 structure is formed at the interface.

At this time, the titanium film 107 is the nitrogen-containing titanium film 1 on the oxide film such as the element isolation insulating film 102.
Since it is formed as 10, the nitrogen-containing titanium film 11
The nitriding reaction of titanium at 0 is promoted, and overglow caused by the reaction of the diffused silicon and titanium on the oxide film 102 is suppressed. In addition, even if the film thickness of the titanium film 107 is reduced with the miniaturization of the element, the nitrogen-containing titanium film 1 is subjected to the heat treatment in the argon atmosphere.
Since the diffusion of nitrogen in 10 is suppressed, the nitriding reaction of titanium in the region on the lower surface side where the nitrogen-containing titanium film 110 is in contact with silicon is suppressed, so that the contact region with silicon has a suitable thinness. Silicide layer 109
Is formed.

Thereafter, as shown in FIG. 6B, the nitrogen-containing titanium 110 is removed by etching with a chemical solution containing a mixture of an aqueous ammonia solution and a hydrogen peroxide solution. As a result, only the titanium silicide layer 109 is left on the surface of silicon. Furthermore, the second temperature of about 800 ° C in an argon atmosphere
When the heat treatment is performed for 10 seconds, the titanium silicide layer 109 having the C49 structure is changed to the titanium silicide layer 111 having the C54 structure.

Also at this time, the phase transition temperature can be lowered by performing the argon heat treatment. Therefore, the processing temperature when changing the silicide layer having the C49 structure to the silicide layer having the C54 structure can be reduced as compared with the case of the nitrogen atmosphere as described above, and the characteristic deterioration of the element such as the MOS transistor due to the high temperature processing can be prevented. .

Here, in each of the above-described embodiments, the silicidation reaction is performed in an argon atmosphere, but an atmosphere of an inert gas, for example, a gas atmosphere of neon, helium, or the like,
Alternatively, the present invention can be similarly applied in a vacuum atmosphere. Further, in this case, it is preferable that the refractory metal film and the refractory metal film containing nitrogen on the refractory metal film are continuously formed in the same apparatus under vacuum or in the same gas atmosphere. Furthermore, it is preferable that subsequent heat treatment steps are also continuously performed in the same apparatus in a vacuum or in the same gas atmosphere. For example, when applied to the first embodiment described above, in the step of FIG. 1B, the silicon substrate 101 is placed in a vacuum atmosphere of a sputtering apparatus, and the titanium film 107 is formed by a sputtering method. . Further, a titanium nitride film 108 is formed on the titanium film 107 while the silicon substrate 101 is held in this sputtering apparatus. Continuing, silicon substrate 101
Is heated by lamp heating while being held in the same sputtering apparatus.

In this method, the titanium film 107 and the titanium nitride film 108 are not exposed to the atmosphere after being formed, and the interface between the titanium film 107 and the titanium nitride film 108 or the surface of the titanium nitride film 108 is exposed to the atmosphere. It is not oxidized by oxygen. In particular, when the silicon substrate 101 is held in the same sputtering apparatus until the step of performing lamp heating after forming the titanium nitride film 108, the above-mentioned oxidation by oxygen in the atmosphere is prevented until immediately before this heating step. As a result, it is possible to prevent oxygen from diffusing into the titanium film 107 and suppressing the reaction between titanium and silicon in this heating step, and when the film thickness of the titanium film 107 is reduced as the element is miniaturized. However, the silicide layers 109 and 111 having a suitable thickness can be formed.

On the other hand, the solid phase diffusion of excess nitrogen atoms from the refractory metal containing nitrogen to the refractory metal in the lower layer is suppressed to 30
It is also possible to form a silicide layer having a low resistivity by using a thin titanium film having a thickness of nm or less. 7 and 8 are sectional views showing the third embodiment of the present invention using this method in the order of steps. Here, the same steps as those in the first embodiment are performed until the titanium film is formed. That is, FIG.
As shown in (a), an element isolation insulating film 102 having a film thickness of 300 nm is formed by a LOCOS method in a predetermined region of a silicon substrate 101 in which a P conductivity type or a P well is formed. Impurities for channel stopper are ion-implanted into the element region of the silicon substrate 101, and a gate insulating film 103 having a film thickness of about 8 nm is formed thereon by thermal oxidation.

Then, a film thickness of 100 is formed on the entire surface by the CVD method.
A polysilicon film of about nm is formed, and impurities such as phosphorus are doped to reduce the resistance. After that, pattern formation is performed by the photolithography technique to form the gate electrode 104. Then, the film thickness is 1 on the entire surface by the CVD method.
A spacer 105 is formed on the side surface of the gate electrode 104 by depositing a silicon oxide film of about 00 nm and etching the silicon oxide film by anisotropic etching. Then, impurities such as arsenic and boron are ion-implanted into the silicon substrate 101, and the diffusion layer 10 as a source / drain region is subjected to heat treatment at about 900 temperature.
6 are formed. Here, the dose of arsenic ions is 1 ×
It is set to about 10 ¹⁵ ions / cm ² .

Next, as shown in FIG. 7B, a titanium film 107 having a thickness of 30 nm or less is formed on the entire surface by the sputtering method. Immediately after this, the silicon substrate is exposed to the atmosphere. As a result, as shown in FIG. 7C, the surface of the titanium film 107 is reacted with oxygen in the atmosphere to form a thin titanium oxide film 112. Then, as shown in FIG. 8A, a titanium nitride film 108 having a thickness of 20 nm or less is formed on the titanium oxide film 112. After that, heat treatment is performed at 700 ° C. for 30 seconds by lamp annealing in an argon atmosphere, so that the titanium film 107 becomes the gate electrode 104.
A silicidation reaction is performed in a region in contact with silicon, such as the diffusion layer 106 or the like, and a titanium silicide layer 109 having a C49 structure is formed at the interface as shown in FIG. 8B.

At this time, on the oxide film 102, the nitrogen from the upper titanium nitride film 108 is converted into titanium oxide film 11.
2 is diffused into the titanium film 107 through the titanium film 107.
The nitrogen-containing titanium 110 is formed on the upper surface side of the above, and overgrowth due to the reaction of the diffused silicon and titanium on the oxide film 102 is suppressed. On the other hand, the titanium nitride film 108 is formed by the titanium oxide film 112.
Since the excessive solid phase diffusion of nitrogen from the titanium film to the titanium film 107 is suppressed, the silicidation reaction at the interface between the silicon substrate 101 and the titanium film 107 is not excessively suppressed by the nitriding reaction, and is about 30 nm. Thin titanium film 107
Also in this case, the titanium silicide layer 109 having a desired thickness and quality is formed. The subsequent steps are the same as those in the first embodiment, and as shown in FIG. 2A, the titanium nitride film 108 and the nitrogen-containing titanium film 110 are etched with a chemical solution in which an aqueous ammonia solution and a hydrogen peroxide solution are mixed. After removal, only the titanium silicide layer 109 is left on the surface of silicon such as the gate electrode 104 and the diffusion layer 106. further,
The second heat treatment at about 800 ° C. in an argon atmosphere is performed 10 times.
2 seconds, the titanium silicide layer 109 having the C49 structure is converted into the titanium silicide layer 111 having the C54 structure as shown in FIG. 2B.

Here, the step of FIG. 8A, that is, the titanium film 107 is formed and exposed to the air, and the titanium oxide film 1 is formed.
A TEM photograph of a cross section at the time when the titanium nitride film 108 is formed after forming 12 is shown in FIG. As can be seen from this photograph, the titanium oxide film 112 is formed here with a thickness of about 3 nm. And this three-layer structure SIMS
10 and 11 show profile data according to the above.
FIG. 10 shows a profile before heat treatment in an argon atmosphere, and FIG. 11 shows a profile after heat treatment at 700 ° C. for 30 seconds in an argon atmosphere. As shown in FIG. 10, it can be understood from the film thickness of the oxygen peak existing between the titanium film 107 and the titanium nitride film 108 that the titanium oxide film 112 exists with a film thickness of about 10 nm. Also,
It can be seen that after the heat treatment shown in FIG. 11, the titanium oxide film 112 is pushed to the bottom of the titanium film 107 due to the diffusion of nitrogen atoms. Thus, the diffusion of nitrogen occurs toward the bottom of the titanium film 107 due to the heat treatment, but the titanium oxide film 112 serves as a wall to suppress the diffusion of nitrogen, and
Oxygen itself is also diffused toward the bottom of the titanium film 107.
That is, the titanium oxide film 112 formed after the titanium film 107 is formed suppresses the diffusion of nitrogen, and the silicidation reaction becomes relatively dominant.

Therefore, by utilizing this, it becomes possible to form the silicide reaction even in the narrow line width portion formed by the titanium film 107 and the like. FIG. 12 shows the silicide line width dependence of the resistance value of the silicide layer. As can be seen from FIG. 6C, the layer resistance of the silicide layer having a line width of 0.5 μm or less was 30Ω, but the layer resistance was reduced to about 10Ω, and an effective silicide layer was formed even in this line width. Backed up. According to the experiments conducted by the present inventor, it was found that the composition ratio of titanium and oxygen in the titanium oxide film is preferably in the range of 1: 1 to 1: 2.

Further, by promoting the silicidation reaction, 30n
As a method of forming a silicide layer having a low resistivity even in a thin titanium film having a thickness of m or less, heat treatment may be performed in a hydrogen atmosphere after the titanium film is formed. 13 and 14
[FIG. 7] is a sectional view showing a fourth embodiment of the present invention using this method in order of steps. Here, the same steps as those in the first embodiment are performed until the titanium film is formed. That is, as shown in FIG. 13A, L is formed in a predetermined region of the silicon substrate 101 in which P conductivity type or P well is formed.
Element isolation insulating film 1 having a thickness of 300 nm formed by the OCOS method
02 is formed. Impurities for channel stopper are ion-implanted into the element region of the silicon substrate 101,
Then, a gate insulating film 103 having a film thickness of about 8 nm is formed by a thermal oxidation method.

Then, a film thickness of 100 is formed on the entire surface by the CVD method.
A polysilicon film of about nm is formed, and impurities such as phosphorus are doped to reduce the resistance. After that, pattern formation is performed by the photolithography technique to form the gate electrode 104. Then, the film thickness is 1 on the entire surface by the CVD method.
A spacer 105 is formed on the side surface of the gate electrode 104 by depositing a silicon oxide film of about 00 nm and etching the silicon oxide film by anisotropic etching. Then, impurities such as arsenic and boron are ion-implanted into the silicon substrate 101, and the diffusion layer 10 as a source / drain region is subjected to heat treatment at about 900 temperature.
6 are formed. Here, the dose of arsenic ions is 1 ×
It is set to about 10 ¹⁵ ions / cm ² .

Next, as shown in FIG. 13B, a titanium film 107 having a thickness of 30 nm or less is formed on the entire surface by the sputtering method. Then, after this, in a hydrogen atmosphere,
Heat treatment is performed at 40 ° C. for 10 seconds. By this heat treatment in a hydrogen atmosphere, hydrogen atoms penetrate into the crystal lattice of the titanium film 107 and the titanium film 1 is formed, as shown in FIG.
07 causes a structural change to the hydrogen-containing titanium film 113,
When the titanium film 107 is formed, the formation of the amorphous Ti—Si interdiffusion region 114 formed between the titanium film 107 and the gate electrode 104 and the diffusion layer 106 is promoted.

Then, as shown in FIG. 14A, the titanium nitride film 10 having a thickness of 20 nm or less is formed on the titanium film 107.
8 is deposited. Then, heat treatment is performed at 700 ° C. for 30 seconds by lamp annealing in an argon atmosphere, and a silicidation reaction is performed in a region where the titanium film 107 is in contact with silicon such as the gate electrode 104 and the diffusion layer 106. As shown in FIG. 14B, a titanium silicide layer 109 having a C49 structure is formed on the interface. At this time, since the above-described amorphous Ti—Si interdiffusion region 114 exists in the formation region of the silicide layer 109, the silicide reaction is promoted, and a high-quality silicide layer is formed even in a thin titanium film having a thickness of 30 nm or less. Can be formed. Further, on the oxide film 102, the nitrogen-containing titanium film 110 is formed.
As described above, the overgrowth of the silicide is suppressed by the formation of the.

After that, as in the first embodiment, as shown in FIG.
As shown in (a), the titanium nitride film 108 and the nitrogen-containing titanium film 110 are removed by etching with a chemical solution in which an aqueous ammonia solution and a hydrogen peroxide solution are mixed, so that only the titanium silicide layer 109 has the gate electrode 104 and the diffusion layer 106. Etc. are left on the surface of silicon. Further, when the second heat treatment at about 800 ° C. is performed for 10 seconds in an argon atmosphere,
As shown in (b), the titanium silicide layer 109 having the C49 structure is changed to the titanium silicide layer 111 having the C54 structure.

In the fourth embodiment, the heat treatment in the hydrogen atmosphere may be performed after the titanium nitride film 108 is formed on the titanium film 107. That is, FIG.
5 (a) and 15 (b), after the titanium film 107 is formed in the same process as in the third embodiment, the titanium nitride film 108 is subsequently formed thereon as shown in FIG. 15 (c). Form. Then, as shown in FIG. 16A, by performing heat treatment in a hydrogen atmosphere, hydrogen atoms enter the crystal lattice of titanium, and the titanium film 107 becomes the hydrogen-containing titanium film 11.
3 causes a structural change to promote the formation of the amorphous Ti—Si interdiffusion region 114. Therefore, FIG.
When the silicidation reaction is performed to form the silicide layer 109 as in 6 (b), the silicidation reaction is not excessively suppressed even by the nitriding reaction, and a high-quality silicide layer can be formed.

As the refractory metal in the present invention, it is possible to use other metals such as tungsten and molybdenum in addition to the above-mentioned titanium.

[0041]

As described above, according to the present invention, the first refractory metal film such as a titanium film formed on silicon has the second refractory metal film containing nitrogen formed thereon, or Nitrogen is ion-implanted into the first refractory metal film itself, and then a heat treatment is performed in an atmosphere containing no nitrogen to perform a silicidation reaction to form a silicide layer. On the existing oxide film, the nitrogen from the second refractory metal film or the ion-implanted nitrogen is diffused into the first refractory metal film to promote the nitriding reaction of the refractory metal film and diffused. Overgrowth due to the reaction between silicon and the refractory metal is suppressed. Further, even when the film thickness of the first refractory metal film is reduced with the miniaturization of the element, the nitriding reaction of the refractory metal in the region on the lower surface side where the refractory metal is in contact with silicon is suppressed. , A suitably thin silicide layer is formed. Further, by performing the heat treatment in a nitrogen-free atmosphere, the phase transition temperature can be lowered, and the characteristic deterioration due to the high temperature treatment of the element can be prevented.

Further, in the present invention, the formation of the refractory metal and the heat treatment thereof are continuously performed in the atmosphere of the same apparatus, or an oxide film is formed on the surface of the first refractory metal film, and further, the first refractory metal film is formed. By adopting a treatment such as heat-treating the refractory metal film No. 1 in a hydrogen atmosphere to transform it into a hydrogen-containing refractory metal film, the above-mentioned silicide layer can be formed more suitably.

[Brief description of the drawings]

FIG. 1 is a first cross-sectional view showing the manufacturing method of the first embodiment of the present invention in the order of steps.

FIG. 2 is a second sectional view showing the manufacturing method according to the first embodiment of the present invention in the order of steps;

FIG. 3 is a diagram showing a comparison of diffusion depths of nitrogen atoms after heat treatment in an argon atmosphere and a nitrogen atmosphere.

FIG. 4 is a diagram showing a titanium film thickness dependency of a phase transition temperature in a heat treatment in an argon atmosphere.

FIG. 5 is a first sectional view showing the manufacturing method according to the second embodiment of the present invention in the order of steps;

FIG. 6 is a second sectional view showing the manufacturing method according to the second embodiment of the present invention in the order of steps;

FIG. 7 is a first cross-sectional view showing the manufacturing method of the third embodiment in the order of steps.

FIG. 8 is a second sectional view showing, in the order of steps, the manufacturing method according to the third embodiment of the present invention.

FIG. 9 is a TEM in the middle of a manufacturing process of the third embodiment.
It is sectional drawing by a photograph.

FIG. 10 is a SIMS profile of a three-layer structure before the heat treatment of the third embodiment.

FIG. 11 is a SIMS profile of a three-layer structure after the heat treatment of the third embodiment.

FIG. 12 is a diagram showing the dependency of the resistance value of the silicide layer on the silicide line width.

FIG. 13 is a first sectional view showing the manufacturing method according to the fourth embodiment of the present invention in the order of steps.

FIG. 14 is a second sectional view showing the manufacturing method according to the fourth embodiment of the present invention in the order of steps.

FIG. 15 is a first cross-sectional view showing the manufacturing method of the modified example of the fourth embodiment of the present invention in the order of steps.

FIG. 16 is a second sectional view showing, in the order of steps, the manufacturing method according to the modification of the fourth embodiment of the present invention.

FIG. 17 is a first sectional view showing an example of the conventional manufacturing method in the order of steps.

FIG. 18 is a second sectional view showing the example of the conventional manufacturing method in the order of steps.

FIG. 19 is a first sectional view showing another example of the conventional manufacturing method in the order of steps.

FIG. 20 is a second sectional view showing another example of the conventional manufacturing method in the order of steps.

FIG. 21 is a diagram showing the titanium film thickness dependence of the phase transition temperature during heat treatment in a nitrogen atmosphere.

[Explanation of symbols]

 101 silicon substrate 102 element isolation insulating film 103 gate oxide film 104 gate electrode 105 stopper 106 diffusion layer 107 titanium film 108 titanium nitride film 109 C49 structure silicide layer 110 nitrogen-containing titanium film 111 C54 structure silicide layer 112 titanium oxide film 113 hydrogen-containing titanium Film 114 Amorphous Ti-Si interdiffusion region

Claims (13)

[Claims] 1. A step of forming a first refractory metal film on the surface of silicon, and a second refractory metal film containing the same material and containing nitrogen is formed on the first refractory metal film. And a heat treatment to form a refractory metal silicide layer at the interface between the silicon and the first refractory metal film, wherein the heat treatment is performed in an atmosphere containing no nitrogen atoms. Manufacturing method. 2. A step of forming an oxide film for element isolation and a gate oxide film on a silicon substrate, forming a gate electrode on the gate oxide film, and a step of forming a stopper made of an insulating film on a side surface of the gate electrode. A step of introducing impurities into the silicon substrate to form source / drain diffusion layers, a step of forming a first refractory metal film on the entire surface, and a second refractory metal containing nitrogen thereon. A step of forming a film,
Performing a heat treatment in an inert gas atmosphere to form a refractory metal silicide layer at the contact interface between the first refractory metal film and the gate electrode and diffusion layer; and the first and second refractory metal films. And a step of performing a heat treatment to cause a phase transition of the refractory metal silicide layer, a method of manufacturing a semiconductor device. 3. A step of forming a first refractory metal film on the surface of silicon, a step of introducing nitrogen into the refractory metal film by ion implantation, and a heat treatment to form silicon and the first refractory metal.
2. A method of manufacturing a semiconductor device, comprising the step of forming a refractory metal silicide layer at the interface with the refractory metal film, wherein the heat treatment is performed in an atmosphere containing no nitrogen atoms. 4. A step of forming an oxide film for element isolation and a gate oxide film on a silicon substrate, forming a gate electrode on the gate oxide film, and a step of forming a stopper made of an insulating film on a side surface of the gate electrode. A step of introducing impurities into the silicon substrate to form a source / drain diffusion layer, a step of forming a refractory metal film on the entire surface, and a step of implanting nitrogen atoms into the refractory metal film. Performing a heat treatment in an inert gas atmosphere to form a refractory metal silicide layer at the contact interface between the refractory metal film, the gate electrode and the diffusion layer; a step of removing the refractory metal film; and a heat treatment. A step of causing a phase transition of the refractory metal silicide layer. 5. The method of manufacturing a semiconductor device according to claim 1, wherein the atmosphere containing no nitrogen atom is an atmosphere of an inert gas such as argon or a vacuum atmosphere. 6. The semiconductor device according to claim 1, wherein the formation of the first refractory metal film and the formation of the second refractory metal film containing nitrogen are performed in an inert gas atmosphere or a vacuum atmosphere of the same apparatus. Production method. 7. The method according to claim 1 or 2, wherein the formation of the first refractory metal film, the formation of the second refractory metal film containing nitrogen, and the heat treatment are performed in an inert gas atmosphere or a vacuum atmosphere in the same apparatus. Of manufacturing a semiconductor device of. 8. A step of forming a first refractory metal film on a silicon surface, a step of forming an oxide film of the refractory metal on the first refractory metal film, and a step of forming an oxide film of the refractory metal on the oxide film. A step of forming a second refractory metal film containing the same material as the first refractory metal film and containing nitrogen; and a heat treatment to form a refractory metal silicide layer at the interface between the silicon and the first refractory metal film. A method of manufacturing a semiconductor device, comprising the step of: forming the semiconductor device, wherein the heat treatment is performed in an atmosphere containing no nitrogen atoms. 9. The manufacturing of a semiconductor device according to claim 8, wherein after the formation of the first refractory metal film, the surface of the first refractory metal film is oxidized in the atmosphere or an atmosphere containing oxygen to form an oxide film. Method. 10. A step of forming a first refractory metal film on a silicon surface, and a step of performing heat treatment in an atmosphere containing hydrogen to transform the first refractory metal film into a hydrogen-containing refractory metal film. Forming a second refractory metal film containing the same material as the first refractory metal film and containing nitrogen on the hydrogen-containing metal film; heat-treating the silicon and the first refractory metal film; A method of manufacturing a semiconductor device, comprising the step of forming a refractory metal silicide layer at the interface of, and performing the heat treatment in an atmosphere containing no nitrogen atoms. 11. The method of manufacturing a semiconductor device according to claim 10, wherein the step of performing the heat treatment in an atmosphere containing hydrogen is performed after forming the first refractory metal film and the second refractory metal film in a stacked state. 12. The method of manufacturing a semiconductor device according to claim 1, wherein the first and second refractory metals are titanium. 13. The film thickness of the first refractory metal film is 30 nm.
13. The method for manufacturing a semiconductor device according to claim 1, wherein: