JPH09289178A - Semiconductor device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of junction leak or the like which are to be caused by reaction between a metal silicide and a metal layer thereon at the time of thermal treatment, in a semiconductor device. SOLUTION: After connection holes 8 is formed or before an insulating film 7 is deposited, a semiconductor device is fixed on a cathode 11 of a plasma generating equipment. For example, the surface of a metal silicide layer such as a titanium silicide film 6 is exposed to plasma of gas containing nitrogen at a temperature lower than or equal to 550 deg.C. By this treatment, a barrier compound layer 14 composed of nitrogen-oxygen-metal-intersilicon compound is formed in a region in the vicinity of the surface of the metal silicide film such as the titanium silicide film 6. Reaction between the metal silicide layer and a buried layer in the later thermal treatment can be obstructed, while the buried layer is formed by using material having excellent step-difference coverage, e.g. an Al-Ti compound layer 15 and an aluminum alloy film 16, without depositing barrier metal such as titanium nitride . a nitride film on the connection holes 8. Thereby contact resistance, sheet resistance, and junction leak are reduced, and reliability can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a silicide layer and a method of manufacturing the same, and more particularly to improvement of a structure of a contact portion between the silicide layer upper wiring and an upper low resistance metal film. .

[0002]

2. Description of the Related Art In recent years, with higher integration and higher density of VLSI, metal silicide layers are formed on the surfaces of gate electrodes and source / drain regions of MOS transistors mounted on VLSI in a self-aligned manner. , Gate electrode, source
A technique (salicide technique) is used that reduces the sheet resistance of the drain region and reduces parasitic resistance such as contact resistance and diffusion resistance to improve the operation speed of the semiconductor element.

By the way, as a method for forming a buried layer made of aluminum, tungsten, and copper on the metal silicide layer, for example, a high temperature sputtering method utilizing the fluidity of an aluminum alloy at a high temperature, or a chemistry excellent in coating property. A method is known in which a metal such as aluminum, tungsten, or copper is selectively deposited in a contact hole by a vapor deposition (hereinafter referred to as CVD) method to form a highly reliable buried layer. In that case, a reaction may occur between the metal composing the buried layer and the metal silicide layer, which may cause a problem. That is, high temperature sputtering, selective CVD, or CVD for forming an upper wiring.
Since a thermal history of about 450 to 600 ° C occurs at
The metal silicide and the metal forming the buried layer react with each other, and the reaction product may erode the silicon substrate to cause a junction leak. Therefore, in order to suppress the reaction between the two, a barrier metal such as titanium nitride is generally formed between the buried layer and the metal silicide layer.

A conventional method for forming a buried layer on a metal silicide layer using a high temperature sputtering method will be described below with reference to FIGS. 15 (a) to 15 (d).

First, as shown in FIG. 15A, a gate oxide film 3 made of a silicon oxide film is formed on an active region surrounded by a field oxide film 2 on a silicon substrate 1.
Then, a MOS transistor including a gate electrode 5 made of a polysilicon film, a sidewall 9 made of a silicon oxide film, and a source / drain region 4 made by introducing impurities into the silicon substrate 1 is formed. Then, for example, a titanium film is deposited on the source / drain region 4 and the gate electrode 5 of the MOS transistor by a sputtering method, and 6
After heat treatment at 00-900 ° C, H2SO4-H2O2
By removing the unreacted titanium film with the mixed solution, the titanium silicide film 6 is selectively formed only on the source / drain regions 4 and the gate electrode 5.

Next, as shown in FIG. 15B, an insulating film 7 is formed on the entire surface of the substrate, and a contact hole 8 reaching the titanium silicide film 6 in the source / drain region 4 is opened in the insulating film 7. To do.

Next, as shown in FIG. 15C, a titanium film for improving the contact characteristics with the titanium silicide film 6 on the source / drain region 4 in the connection hole 8 and on the insulating film 7. A titanium nitride film as a barrier metal is deposited by a sputtering method to form a titanium nitride / titanium film 19.

Next, as shown in FIG. 15 (d), titanium is sputtered and then an aluminum alloy is deposited thereon at 500.degree.
Then, the Al—Ti compound layer 15 formed by combining the aluminum alloy and titanium and the aluminum alloy film 16 thereon are formed by sputtering. At that time, Al-
The inside of the connection hole 8 is filled with an aluminum alloy by utilizing the reaction heat between Ti. Then, the titanium nitride / titanium film 19, the Al—Ti compound layer 15, and the aluminum alloy 16 are patterned by photolithography to form metal wiring.

[0009]

However, when the diameter of the connection hole is further miniaturized in accordance with the miniaturization of the semiconductor device, in the above-mentioned conventional method, titanium nitride / titanium nitride is used in the step shown in FIG. 15 (c). It is not preferable to deposit the film 19 by the sputtering method for the following reasons.

In general, since the titanium nitride film formed by the sputtering method does not have good step coverage, an overhang shape is likely to be formed at the upper corner of the connection hole. Therefore, the aluminum alloy is prevented from flowing into the connection hole during high-temperature sputtering, making it difficult to fill the connection hole (for example, Y. Takegawa
Ext. Abst. SSDM, p.558, 1993).

Therefore, when forming a titanium nitride film, there is a method of suppressing the formation of an overhang shape by sputtering titanium through a honeycomb filter (collimator) while flowing N 2 gas. Easy to generate particles.

Further, in the step shown in FIG. 15B, the titanium nitride / titanium film 19 covers the portion other than the connection hole 8 (the portion on the insulating film 7), so that the selection using the difference in the underlying layer is performed. It is not possible to use a method of selectively depositing a metal such as aluminum, tungsten, or copper only in the connection hole 8 by the CVD method.

On the other hand, in order to avoid the above-mentioned problems, after forming the contact hole in the insulating film, heat treatment is performed in an NH3 atmosphere at about 850 ° C. without depositing the titanium nitride / titanium film 19. Proposes a technique of forming a titanium nitride film on the surface of a titanium silicide film and then selectively depositing aluminum only in the contact holes by a selective CVD method (eg, H. Shinriki et al. Ext. Abst. SSDM. , p.9
68, 1994).

However, if heat treatment at 800 ° C. or higher is applied to the titanium silicide film, boron in the source / drain regions may be absorbed in the titanium silicide film, and the saturation current value of the P-channel transistor may be reduced. Further, depending on the type of metal silicide, when heat treatment is performed at a high temperature, the silicide agglomerates to increase the sheet resistance of the source / drain. Therefore, the types of silicide to which the above conventional method can be applied are limited.

Further, the above-mentioned problems are not limited to between the buried layer in the connection hole and the silicide film, and also when a low resistance metal film is formed on the silicide film. Since it occurs, it becomes a cause of deteriorating the reliability in the laminated structure of the silicide film and the metal film.

According to the present invention, when a compound layer made of a nitrogen-oxygen-metal-silicon compound is formed in the vicinity of the boundary between the metal silicide layer and the metal film on the metal silicide layer, it causes a junction leak in the semiconductor substrate. It was made based on the discovery of the fact that such compounds do not invade, and the purpose is to form a compound layer that serves as such a barrier, thereby eliminating the need for a barrier metal and forming a buried layer or a silicide film. While improving the reliability in the laminated structure of the metal film,
It is an object of the present invention to provide a semiconductor device capable of keeping the sheet resistance value of the entire metal silicide film low and preventing the occurrence of a junction leak, and a manufacturing method thereof.

[0017]

In order to achieve the above object, in the present invention, the means relating to the semiconductor device described in claims 1-9 and the semiconductor device described in claims 12-23 are provided. Measures related to the manufacturing method are taken.

According to another aspect of the present invention, there is provided a semiconductor device comprising: a semiconductor substrate; a metal silicide film formed on a part of the semiconductor substrate and having a first metal silicided; A metal film made of a second metal formed on the metal silicide film, and nitrogen-oxygen-first metal-formed in a region near the surface of the metal silicide film.
And a barrier compound layer made of an inter-silicon compound.

As a result, since the barrier compound layer made of the nitrogen-oxygen-metal-silicon compound is formed on the surface of the metal silicide film, there is a history of high temperature during the manufacturing process such as when depositing the metal film. Also, the reaction between the first metal forming the metal silicide film and the second metal forming the metal film is suppressed. That is, titanium nitride
The occurrence of junction leakage and the deterioration of the characteristics of the gate oxide film are suppressed without interposing a barrier metal such as a nitride film. Therefore, it is possible to avoid problems caused by poor step coverage and resistance characteristics of the barrier metal, such as a decrease in reliability and an increase in sheet resistance.

As described in claim 2, in claim 1, it is preferable that the barrier compound layer is formed in a region near the surface of the entire metal silicide film.

As a result, the manufacturing process of the semiconductor device is simplified and the chemical resistance of the metal silicide layer is improved, so that the manufacturing cost can be reduced.

As described in claims 3 and 4, in claim 1 or 2, the thickness of the barrier compound layer is
It is preferable that the thickness is at least a thickness sufficient to prevent the diffusion of the second metal into the barrier compound layer and 30% or less of the thickness of the metal silicide film, or from another viewpoint, a thickness of 2 to 20 nm. It is preferably in the range.

As a result, the increase in contact resistance and sheet resistance due to the formation of a too thick barrier compound layer can be suppressed as much as possible.

As described in claim 5, in claim 1, 2, or 3, the position where the concentration of nitrogen in the barrier compound layer is maximized is higher than the position where the concentration of oxygen is maximized. It is preferable to locate it at the back.

As a result, the oxygen concentration becomes relatively low at the position where the nitrogen concentration becomes high, so that the region where the concentration of the oxide layer is high, which causes an increase in contact resistance and sheet resistance, is suppressed near the surface. be able to. Therefore, an increase in sheet resistance or the like at the contact portion between the metal film and the silicide film can be suppressed as much as possible.

According to a sixth aspect of the present invention, in the first aspect, the insulating film formed on the metal silicide film and the connection formed on a part of the insulating film and reaching the metal silicide film. A hole may be further provided, and the metal film may be a buried layer made of the second metal deposited in the connection hole.

Thus, since the barrier compound that suppresses the reaction between the first metal and the second metal exists in the region near the surface of the metal film, it is not necessary to form the barrier metal in the connection hole. Therefore, it is possible to select a second metal having a good coverage as the second metal forming the burying layer in the connection hole, which is particularly required to have the step coverage, and the reliability of the semiconductor device is improved.

According to a seventh aspect of the present invention, in the first aspect, the insulating film formed on the metal silicide film and the connection formed on a part of the insulating film and reaching the metal silicide film. The method may further include a hole and a buried layer made of the third metal deposited in the connection hole.

As a result, a material having a low electric resistance can be selected as the metal film made of the second metal and the low resistance layer can be interposed between the buried layer and the metal silicide film. Thus, a semiconductor device suitable for miniaturization can be obtained.

As described in claim 8, in claim 1, 2, 3, 4, 5, 6 or 7, said first metal is titanium, cobalt, nickel, tantalum, tungsten, niobium, It is preferably composed of at least one of palladium, platinum and molybdenum.

As described in claim 9, in claim 1, 2, 3, 4, 5, 6 or 7, the second metal is a metal containing aluminum, a metal containing copper and tungsten. It is preferable to be composed of at least one of the included metals.

According to a tenth aspect of the method of manufacturing a semiconductor device of the present invention, a first step of forming a metal silicide film made of a compound of a first metal and silicon on a semiconductor substrate. And irradiating the surface of the metal silicide film with ions containing nitrogen under a neutral or oxidizing atmosphere to form a region near the surface of the metal silicide film with nitrogen-oxygen-first metal-silicon compound. The method includes a second step of forming a barrier compound layer and a third step of depositing a second metal on the barrier compound layer of the metal silicide film to form a metal film.

According to this method, since the barrier compound layer is formed on the surface of the metal silicide film in the second step, it is possible to form the metal film in the third step without forming the barrier metal. . Therefore,
By appropriately selecting and using a material having a good step coverage as the second metal, the step coverage with respect to the base of the metal film is improved, and a highly reliable semiconductor device can be formed.

As described in claim 11, in claim 10, a step of forming an insulating film on the metal silicide film after the first step and before the second step. And a step of selectively removing a part of the insulating film to form a connection hole reaching the metal silicide film. In the second step, in the region near the surface of the metal silicide film, The barrier compound layer may be formed in a region exposed at the bottom of the contact hole, and in the third step, the inside of the contact hole may be filled with the second metal.

According to this method, the region where the barrier compound layer is formed is limited to a particularly required region, so that the increase in sheet resistance of the metal silicide film is suppressed.

According to a twelfth aspect, in the tenth aspect, after the second step, a step of forming an insulating film on the barrier compound layer of the metal silicide film; and the insulating film. A step of selectively removing a part of the above to form a connection hole reaching the barrier compound layer, and in the third step, the second metal may be deposited in the connection hole. it can.

According to this method, since the barrier compound layer is formed at any portion when the contact is formed from each wiring layer at an arbitrary position of the metal silicide film, the barrier compound layer is formed every time the contact hole is formed. The process is simplified as no layers need to be formed. Further, the resistance of the metal silicide film to chemicals such as HF is also improved,
The restrictions on the subsequent steps will be relaxed.

As described in claim 13, in claim 12, after the third step, a step of forming an insulating film on the barrier compound layer of the metal silicide film; and the insulating film. Further comprising the step of selectively removing a part of the above to form a connection hole reaching the barrier compound layer, and the step of depositing a third metal in the connection hole to form a buried layer. You can

By this method, when a material having a low electric resistance is selected as the second metal, a low resistance layer is formed on the metal silicide film and a buried layer is formed on the low resistance layer. A semiconductor device having good characteristics can be obtained.

As described in claim 14, in claim 10, 11, 12 or 13, in the second step, a lower electrode as a cathode and an upper electrode as an anode are arranged in the chamber. The barrier compound layer can be formed by exposing the metal silicide film to plasma of a gas containing nitrogen while the semiconductor substrate is placed on the lower electrode in the chamber using a plasma generator. .

By this method, by placing a semiconductor substrate on the cathode, nitrogen, which is a positive ion in nitrogen plasma, is efficiently taken into the metal silicide.

According to a fifteenth aspect, in the tenth, the eleventh, the twelfth, or the thirteenth aspect, in the second step, the surface of the metal silicide film is exposed to a gas containing nitrogen and ultraviolet rays and ionizing radiations are applied. The barrier compound layer can be formed by irradiating either one of them.

As described in claim 16, in claim 10, 11, 12 or 13, in the second step, the surface of the metal silicide film is exposed to an ion beam containing nitrogen. A barrier compound layer can be formed.

As described in claim 17, in claim 10, 11, 12, 13, 14, 15 or 16, the second step is preferably performed at 550 ° C. or lower.

By this method, plasma treatment or the like is performed under a low temperature condition of 550 ° C. or less, so that even if titanium silicide or the like is used, aggregation of metal silicide is not caused, and the selection range of metal silicide types is expanded. It

As described in claim 18, in claim 10, 11, 12, 13, 14, 15 or 16, in the second step, the nitrogen-containing gas is N 2.
Two gases can be used.

According to this method, when forming the barrier compound layer, the barrier compound layer composed of the nitrogen-oxygen-metal-silicon compound is easily formed by utilizing the natural oxide film existing on the surface of the metal silicide film. To be done.

As described in claim 19, in claim 10, 11, 12, 13, 14, 15, 16, 17 or 18, a gas containing hydrogen is flowed before the second step. Thus, the method further includes the step of removing the natural oxide film on the metal silicide film, and the gas containing oxygen can be added in the second step.

By this method, the oxygen concentration in the barrier compound layer is controlled, so that the distribution state of each element can be adjusted to a more preferable state.

As described in claim 20, in claim 10, 11, 12, 13, 14, 15 or 16, in the second step, ions containing nitrogen are added at 3 keV.
It is preferable to introduce into the metal silicide film with the following ion energy.

According to this method, the region where the barrier compound layer is formed is limited to the depth of about 20 nm from the surface of the metal silicide film, so that the increase in contact resistance and sheet resistance of the formed semiconductor device is suppressed. It will be.

As described in claim 21, claims 10, 11, 12, 13, 14, 15, 16, 17,
18, 19, or 20, in the first step, titanium, cobalt, nickel,
It is preferable to form a silicide film of any one of tantalum, tungsten, palladium, platinum and molybdenum.

As described in claim 22, claims 10, 11, 12, 13, 14, 15, 16, 17,
18, 19, or 20, in the third step, C
It is preferable to deposit one of a metal containing aluminum, a metal containing copper, and a metal containing tungsten by a VD method.

As described in claim 23, claim 10, 11, 12, 13, 14, 15, 16, 17,
18, 19, or 20, in the third step, the metal film can be formed of an Al—Ti compound layer and an aluminum alloy film by continuously sputtering titanium and an aluminum alloy.

By these methods, it is possible to select the method of forming the metal film and the wiring according to the type of the semiconductor device and the difference in the wiring layer formed on the metal silicide film.

[0056]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIGS. 1A to 1D are sectional views showing manufacturing steps of a semiconductor device according to the first embodiment.

First, as shown in FIG. 1A, a gate oxide film 3 made of a silicon oxide film is formed on an active region surrounded by a field oxide film 2 on a silicon substrate 1.
Then, a MOS transistor including a gate electrode 5 made of a polysilicon film, a sidewall 9 made of a silicon oxide film, and a source / drain region 4 made by introducing impurities into the silicon substrate 1 is formed. Then, for example, a titanium film is deposited on the substrate by a sputtering method, and the temperature is 650 ° C.
After the heat treatment is performed in the above step, the unreacted titanium film is removed with a mixed solution of H2 SO4 and H2 O2 to selectively form the titanium silicide film 6 having a thickness of about 70 nm only on the source / drain region 4 and the gate electrode 5. To form. Then 8
Heat treatment is performed at 50 ° C. to reduce the resistance of the titanium silicide film.

Next, as shown in FIG. 1B, an insulating film 7 having a thickness of about 800 nm is formed on the entire surface of the substrate,
A contact hole 8 reaching the titanium silicide film 6 in the source / drain region 4 is opened in the insulating film 7.

Next, as shown in FIG. 1C, a plasma generator having an anode 10 and a cathode 11 forming a parallel plate electrode, a blocking capacitor 12 and a high frequency power source 13 is used. A semiconductor device that has undergone the steps up to FIG. 1B is placed on a cathode 11 arranged in a reaction chamber (not shown), and the surface of the titanium silicide film 6 is exposed to plasma of a nitrogen-containing gas. For example, 100% N2 at a temperature of 50 ° C and a pressure of 80 mTorr.
A gas is introduced to generate an electric power of 30 between the parallel plate electrodes 10 and 11.
A high frequency power of about 0 W is applied for 300 seconds. At this time, nitrogen plasma Plz is generated in the reaction chamber. Nitrogen in the nitrogen plasma Plz has become positive ions such as N + and N2 +, and a total potential of 300V is generated in the direction of the cathode 11 by adding the plasma potential of about 60V and the self-bias voltage of about 240V. Then, nitrogen ions are attracted to the surface of the semiconductor device at this potential. That is, the parallel plate type electrode 10,
By disposing the semiconductor device on the cathode 11 of 11, the introduction of nitrogen to the surface of the titanium silicide film 6 is promoted. At this time, oxygen in the natural oxide layer formed on the surface of the titanium silicide film 6 is also taken into the titanium silicide layer 6, and the barrier compound layer 14 made of the nitrogen-oxygen-titanium-silicon compound is formed into the titanium silicide film 6. Formed near the surface of the.

Next, as shown in FIG. 1D, titanium is sputtered to a thickness of about 75 nm, and then silicon 1 is deposited.
% Aluminum and 0.5% copper alloy at 500 ° C
By sputtering a thickness of about 00 nm, an Al—Ti compound layer 15 formed by combining an aluminum alloy and titanium and an aluminum alloy film 16 thereon are formed. At this time, the reaction heat between Al and Ti is utilized to fill the inside of the connection hole 8 with an aluminum alloy to form a buried layer. Then, the Al—Ti compound layer 15 and the aluminum alloy film 16 are formed by photolithography.
Is patterned to form metal wiring.

A contact hole is also formed on the gate electrode 5 at the same time (in a section different from the section shown in FIGS. 1A to 1D), and the vicinity of the surface of the titanium silicide film 6 on the gate electrode 5 is formed. After forming the barrier compound layer 14 in the above, the Al—Ti compound layer 15 and the aluminum alloy film 16 may be deposited to form the buried layer and the metal wiring.

FIG. 2 shows a sectional structure of a semiconductor device formed by the above-mentioned manufacturing method. That is,
A gate oxide film 3, a gate electrode 5 made of a polysilicon film, and a source / drain region 4 are formed on a silicon substrate 1.
And a titanium silicide film 6 formed on the source / drain region 4 and the gate electrode 5 and a sidewall 9 are formed. And
A connection hole 8 reaching the titanium silicide film 6 on the source / drain region 4 is formed in the insulating film 7 formed on the substrate, and a buried layer and a buried layer are formed in the connection hole 8 and on the insulating film 7. An Al—Ti compound layer 15 and an aluminum alloy film 16 which form a metal wiring are formed. As a characteristic of the semiconductor device according to the present embodiment, a barrier metal such as titanium nitride / nitride film is not formed under the aluminum alloy film 16, and instead the source / drain region 4 is formed.
A barrier compound layer 14 made of a nitrogen-oxygen-titanium-silicon compound is formed only on the surface of a region of the upper titanium silicide film 6 which will be the bottom surface of the connection hole 8.

Next, the details of the structure of the barrier compound layer 14 of the semiconductor device obtained in this embodiment and the details of the contact resistance and the like in the semiconductor device of this embodiment will be described.

FIG. 9 shows the concentration profile of each element obtained as a result of analyzing the region near the surface of the titanium silicide film 6 after the step shown in FIG. 1C in this embodiment by Auger electron spectroscopy. FIG. However,
Since the sensitivities to the respective elements are different in the analysis by Auger electron spectroscopy, FIG. 9 does not accurately show the composition ratio of the respective elements, but merely shows the concentration distribution of each individual element. As shown in FIG. 9, 2-3 nm from the surface
Up to the present, particularly large amounts of silicon and oxygen exist, and it is considered that this is because the SiO2 film was formed as a natural oxide film on the surface of the titanium silicide film in the analysis process. A barrier compound layer made of a nitrogen-oxygen-titanium-silicon compound is formed below the SiO2 film in a range of about 8 nm. And SiO near the surface
When the 2 film is excluded, a peak of oxygen concentration is seen in the immediate vicinity of the surface, and a peak of nitrogen concentration is seen at a depth of about 4 to 5 nm below the SiO2 film.

The bond state between the elements in the barrier compound layer 14 could not be analyzed because the reaction layer was thin, but TiN, TiO2, Si3 N4,
The standard heat of formation of SiO2 is -73.0 kcal /
mol, -218.0 kcal / mol, -179.
3, from -202.5 kcal / mol,
When a titanium silicide film is used as in this embodiment, it is considered that oxygen is bonded to titanium and silicon and nitrogen is bonded mainly to silicon.

As a result of forming this barrier compound layer 14,
The sheet resistance increased from 2.6 Ω / □ to 2.9 Ω / □, but the rate of increase was about 10%, which is a sufficiently low value that does not cause any particular problem in transistor operation or the like. In the present embodiment, since the barrier compound layer 14 made of the nitrogen-oxygen-titanium-silicon compound is formed only on the surface of the titanium silicide film in the contact hole 8, the sheet of titanium silicide 6 obtained by the above-mentioned nitrogen plasma treatment is used. The rate of resistance increase is even smaller.

FIG. 10 shows a sample not subjected to the nitrogen plasma treatment shown in FIG. 1C, a sample subjected to the treatment of this embodiment, and a reference sample (TiN.multidot. It is a figure which compares the junction leak characteristic about the sample which has the barrier metal which consists of Ti film, and has not performed high temperature sputtering. However, the area is 800
The junction leakage characteristics when a reverse voltage of 5.5 V is applied to the 0 μm 2 N + P junction are shown. As shown in the figure, the junction leak is large in the sample which is not subjected to the nitrogen plasma treatment. This is the process shown in FIG.
When the aluminum alloy is sputtered at ℃, the aluminum alloy film 16 or the Al—Ti compound layer 15 reacts with the titanium silicide film 6, aluminum penetrates into the silicon substrate 1, and a junction leak occurs. Conceivable. On the other hand, the junction leak of the sample subjected to the nitrogen plasma treatment according to the present embodiment is equal to the junction leak of the reference sample having the barrier metal and not performing the high temperature sputtering, although it does not have the barrier metal. I know there is. This is because when the aluminum alloy is sputtered at 500 ° C., the aluminum alloy film 16 or A
It is considered that the barrier compound layer 14 prevents the 1-Ti compound layer 15 from reacting with the titanium silicide film 6.

Further, the contact resistance to the N + diffusion region in this embodiment is 15Ω for the sample having a contact shape of 1.0 μm square and subjected to the nitrogen plasma treatment, and the contact resistance of the reference sample is 5Ω. . Although the contact resistance of the sample according to the present embodiment is slightly high, it is understood that no particular problem occurs in the operation of the transistor and the electrical connection with the silicon substrate is sufficient.

FIG. 11 is a diagram showing the annealing temperature dependence of the sheet resistance of various samples which were annealed by depositing an Al alloy after nitrogen plasma treatment. The processing conditions are as follows: a titanium silicide film having a thickness of 70 nm is subjected to the nitrogen plasma processing shown in FIG.
After depositing a -1% Si-0.5% Cu alloy to a thickness of 200 nm, it is annealed for 30 minutes. The sample contains
There are two types: one without nitrogen plasma treatment, one with nitrogen plasma treatment for 20 seconds, one with nitrogen plasma treatment for 60 seconds, and one with nitrogen plasma treatment for 300 seconds. As shown in the figure, when the nitrogen plasma treatment is performed for 60 seconds and the nitrogen plasma treatment is performed for 300 seconds, it is 530
It can be seen that the increase in sheet resistance when annealed at ℃ is suppressed. This figure also shows that the barrier compound layer formed of the nitrogen-oxygen-titanium-silicon compound formed on the surface of the titanium silicide film has an effect of suppressing the reaction between the aluminum alloy and the titanium silicide film.

As described above, according to this embodiment, the surface of the metal silicide is subjected to the nitrogen plasma treatment to form the barrier compound layer of the nitrogen-oxygen-metal-silicon compound on the surface of the metal silicide film. Therefore, it is possible to effectively prevent the metal generated by the reaction between the metal silicide film and the aluminum alloy from entering the silicon substrate by the heat treatment in the subsequent process. That is, it is possible to suppress the occurrence of a junction leak without interposing a barrier metal such as a titanium nitride / nitride film between the buried layer made of an aluminum alloy film and the metal silicide as in the conventional method. Therefore, it is possible to prevent the reliability of the buried layer from being deteriorated as in the case where the barrier metal is provided. Moreover, the contact resistance can be suppressed to a sufficiently low level for practical use, and the sheet resistance of the metal silicide film itself can be kept to a sufficiently low level.

Further, even when the barrier compound layer is formed in the region near the surface of the metal silicide film on the gate electrode 5, the metal can be prevented from entering the gate electrode, so that the characteristics of the gate oxide film are deteriorated. Etc. can be effectively prevented.

In particular, in this embodiment, since the nitrogen plasma treatment is performed at a low temperature of 550 ° C. or less, the metal silicide film is not aggregated with respect to many kinds of metal silicide, that is, the metal silicide is formed. There is an advantage that the range of selection of metal materials can be expanded.

(Second Embodiment) Next, a second embodiment will be described. In this embodiment, although illustration of the manufacturing process is omitted, FIG. 1A in the first embodiment described above is used.
After performing the same process as (c) to (c), a tungsten film 17 to be a buried layer is deposited in the contact hole 8 by the selective CVD method. Then, after depositing the aluminum alloy film 16 on the tungsten film 17 and the insulating film 7, this is patterned to form a metal wiring.

FIG. 3 is a sectional view showing the structure of a semiconductor device formed according to this embodiment. In the first embodiment, the Al—Ti compound layer 15 and the aluminum alloy film 1 are used.
Although the buried layer and the metal wiring are integrally formed by 6 and 6, in the present embodiment, the tungsten film 17 constitutes the buried layer and the aluminum alloy film 16 constitutes the metal wiring. And the source / drain region 4
A barrier compound layer 14 made of a nitrogen-oxygen-titanium-silicon compound is formed only on the bottom surface of the connection hole 8 of the upper titanium silicide film 6, and the tungsten film 17 and the titanium silicide film 6 form this barrier. Compound layer 1
4 are in contact with each other. That is, the semiconductor device of this embodiment is different from the semiconductor device of the first embodiment only in that the buried layer and the metal wiring are made of different materials, and the other parts are the semiconductor of the first embodiment. It has the same structure as the device. Therefore, basically the same effect as that of the first embodiment can be exhibited.

In addition, in the semiconductor device of this embodiment, since the buried layer is made of the tungsten film 17, the temperature at which the reaction causing the junction leak of the semiconductor device occurs is higher than that in the case of the aluminum alloy film or the like. Become. In the present embodiment, the barrier compound layer 14 allows the subsequent 60
By heat treatment at 0 ° C. or higher, it is possible to prevent titanium silicide and tungsten from reacting with each other and causing a metal to enter the silicon substrate to cause a junction leak.

(Third Embodiment) Next, a third embodiment will be described. 4A to 4D are cross-sectional views showing the manufacturing process of the semiconductor device of this embodiment.

First, as shown in FIG. 4A, a gate oxide film 3 made of a silicon oxide film is formed on an active region surrounded by a field oxide film 2 on a silicon substrate 1.
Then, a MOS transistor including a gate electrode 5 made of a polysilicon film, a sidewall 9 made of a silicon oxide film, and a source / drain region 4 made by introducing impurities into the silicon substrate 1 is formed. Then, for example, a titanium film is deposited on the substrate by a sputtering method, and the temperature is 650 ° C.
After the heat treatment is performed in the above step, the unreacted titanium film is removed with a mixed solution of H2 SO4 and H2 O2 to selectively form the titanium silicide film 6 having a thickness of about 70 nm only on the source / drain region 4 and the gate electrode 5. To form. Then 8
Heat treatment is performed at 50 ° C. to reduce the resistance of the titanium silicide film.

Next, as shown in FIG. 4 (b), an anode 10 and a cathode 11 forming a parallel plate electrode, and a DC power source 18
Using a plasma generator having the above, a semiconductor device is placed on a cathode 11 arranged in a reaction chamber (not shown) of the plasma generator, and the surface of the titanium silicide film 6 is a nitrogen-containing gas such as nitrogen gas. Exposed to plasma. Then, as in the first embodiment, oxygen in the natural oxide film formed on the surface of the titanium silicide film 6 is also taken into the titanium silicide film 6, and the entire titanium silicide film 6 is exposed by the plasma of N2 gas. A barrier compound layer 14 made of a nitrogen-oxygen-titanium-silicon compound is formed near the surface.

Next, as shown in FIG. 4C, an insulating film 7 having a thickness of about 800 nm is formed on the entire surface of the substrate,
A contact hole 8 reaching the titanium silicide film 6 in the source / drain region 4 is opened in the insulating film 7.

Next, as shown in FIG. 4 (d), titanium was sputtered by a sputtering apparatus to a thickness of about 75 nm, and then an aluminum alloy containing 1% silicon and 0.5% copper at 500 ° C. By sputtering a thickness of about 900 nm, an Al—Ti compound layer 15 formed by combining an aluminum alloy and titanium and an aluminum alloy film 16 thereon are formed. At this time, the reaction heat between Al and Ti is utilized to fill the inside of the connection hole 8 with an aluminum alloy to form a buried layer. Then, the Al—Ti compound layer 15 and the aluminum alloy film 16 are patterned by photolithography to form metal wiring.

FIG. 5 shows a sectional structure of a semiconductor device formed by the above-described manufacturing method. That is,
A gate oxide film 3, a gate electrode 5 made of a polysilicon film, and a source / drain region 4 are formed on a silicon substrate 1.
Then, a MOS transistor having a titanium silicide film 6 formed on the source / drain regions 4 and the gate electrode 5 and a sidewall 9 is formed. Then, the barrier compound layer 14 made of a nitrogen-oxygen-titanium-silicon compound is formed on the entire surface of the titanium silicide film 6. A connection hole 8 reaching the titanium silicide film 6 on the source / drain region 4 is formed in the insulating film 7 formed on the substrate. The connection hole 8 is buried in the connection hole 8 and on the insulating film 7. Al-constituting layers and metal wiring
A Ti compound layer 15 and an aluminum alloy film 16 are formed. That is, in the semiconductor device of the first embodiment, only the surface of the region of the titanium silicide film 6 on the source / drain region 4 which will be the bottom of the connection hole 8 is
Although the barrier compound layer 14 made of the nitrogen-oxygen-titanium-silicon compound is formed, in the semiconductor device of this embodiment, the titanium silicide film 6 on the source / drain region 4 and the gate electrode 5 is entirely covered. It is characterized in that the barrier compound layer 14 is formed on.

Also in this embodiment, since the barrier compound layer 14 made of the nitrogen-oxygen-titanium-silicon compound is formed in the region near the surface of the titanium silicide film 6, the same as in the first embodiment. The effect is obtained. In particular, according to the method of the present embodiment, the barrier compound layer 14 is formed not only in the source / drain regions 4 but also in the region near the surface of the titanium silicide film 6 on the gate electrode 5. Even when a contact portion is formed on the gate electrode 5 from a wiring layer different from the Al—Ti compound layer 15 and the aluminum alloy film 16 shown, the contact is made via the barrier compound layer 14 without performing the nitrogen plasma treatment again. There is an advantage that can be done.

Before the step shown in FIG. 4D, that is, before the semiconductor device is put in the sputtering apparatus, it is necessary to wet etch the inside of the connection hole 8 with an HF solution to remove the surface oxide layer of the metal silicide. However, the titanium silicide film 6 is easily etched by the HF solution. In this respect, in the present embodiment, the barrier compound layer 14 made of the nitrogen-oxygen-titanium-silicon compound is considered to have a composition close to SiN because it contains a bond between silicon and nitrogen, and therefore the HF solution is used. It is thought that it is difficult to etch with. Therefore, the present embodiment also has an advantage that the chemical resistance of the titanium silicide film is improved and the process margin is increased.

However, in the semiconductor device of this embodiment, since the barrier compound layer 14 is formed on the entire surface of the titanium silicide film 6, the sheet resistance of the titanium silicide film 6 is larger than that of the semiconductor device of the first embodiment. The rise will be great. However, as described in the first embodiment, even in that case, the increase rate of the sheet resistance is about 10%, which is a sufficiently low value that causes no particular problem in the transistor operation and the like.

(Fourth Embodiment) Next, a fourth embodiment will be described. In the present embodiment, although illustration of the manufacturing process is omitted, FIG. 3A in the above-described third embodiment is used.
After performing the same process as (c) to (c), a tungsten film 17 to be a buried layer is deposited in the contact hole 8 by the selective CVD method. Then, after depositing the aluminum alloy film 16 on the tungsten film 17 and the insulating film 7, this is patterned to form a metal wiring.

FIG. 6 is a sectional view showing the structure of a semiconductor device formed according to this embodiment. In the third embodiment, the Al—Ti compound layer 15 and the aluminum alloy film 1 are used.
Although the buried layer and the metal wiring are integrally formed by 6 and 6, in the present embodiment, the tungsten film 17 constitutes the buried layer and the aluminum alloy film 16 constitutes the metal wiring. And the source / drain region 4
Also, a barrier compound layer 14 made of a nitrogen-oxygen-metal-silicon compound is formed on the entire surface of the titanium silicide film 6 on the gate electrode 5, and the tungsten film 17 and the titanium silicide film 6 form the barrier compound layer. 14 are in contact with each other. That is, the semiconductor device of this embodiment differs from the semiconductor device of the third embodiment only in that the buried layer and the metal wiring are made of different materials, and the other parts are the semiconductor device of the third embodiment. It has the same structure as the device.
Therefore, basically the same effect as the third embodiment can be exhibited.

In addition, in the semiconductor device of this embodiment, since the buried layer is made of the tungsten film 17, the barrier compound layer 17 may prevent the reaction between tungsten and titanium silicide. Therefore, in the subsequent heat treatment at 600 ° C. or higher, titanium silicide and tungsten react with each other, and the metal enters the silicon substrate,
It is possible to prevent a junction leak from occurring.

(Fifth Embodiment) Next, a fifth embodiment will be described. 7A to 7D are cross-sectional views showing the manufacturing process of the semiconductor device of this embodiment.

First, as shown in FIG. 7A, a gate oxide film 3 made of a silicon oxide film is formed on an active region surrounded by a field oxide film 2 on a silicon substrate 1.
Then, a MOS transistor including a gate electrode 5 made of a polysilicon film, a sidewall 9 made of a silicon oxide film, and a source / drain region 4 made by introducing impurities into the silicon substrate 1 is formed. Then, for example, a cobalt film is deposited on the substrate by a sputtering method, heat-treated at 500 ° C. in a nitrogen atmosphere, and then H 2 SO 4 —H 2 O 2
By removing the unreacted cobalt film with the mixed solution, the cobalt silicide film 24 having a thickness of about 50 nm is selectively formed only on the source / drain regions 4 and the gate electrode 5. Then, heat treatment is performed at 850 ° C. to reduce the resistance of the cobalt silicide film 24.

Next, as shown in FIG. 7B, an upper electrode 29 and a lower electrode 26 which form a parallel plate electrode, a high pass filter 27, a low pass filter 28, and 1
Using a plasma generator having a high frequency power supply 29 of 3.56 MHz and a high frequency power supply 30 of 400 KHz, a semiconductor device is mounted on a lower electrode 26 arranged in a reaction chamber (not shown) of the plasma generator. Then, the surface of the cobalt silicide film 24 is exposed to plasma of nitrogen-containing gas such as nitrogen gas. For example, at a temperature of 400 ° C and a pressure of 2 Torr,
100% N2 gas was introduced, and 80 W of high frequency power was supplied to the upper electrode 25 by the high frequency power supply 29 and 100 W of high frequency power was supplied to the lower electrode 26 by the high frequency power supply 30 for 900 sec.
Apply for At this time, nitrogen plasma Plz is introduced into the reaction chamber.
Occurs. The nitrogen in this nitrogen plasma Plz is N +, N
Since it is a cation such as 2+ and the lower electrode 26 has a lower frequency, nitrogen ions are attracted toward the lower electrode 25. That is, even if the plasma generator of the dual frequency power addition type is used, the cobalt silicide film 2 can be formed by installing the semiconductor device on the electrode to which the power on the low frequency side is applied.
4 The introduction of nitrogen to the surface will be promoted. At this time, oxygen in the natural oxide layer formed on the surface of the cobalt silicide film 24 or oxygen remaining in the chamber is also taken into the cobalt silicide layer 24, and is a barrier composed of a nitrogen-oxygen-cobalt-silicon compound. The compound layer 14 is formed near the surface of the cobalt silicide film 24.

Next, as shown in FIG. 7C, DMAH
Selection C using (dimethylaluminum hydride)
The first aluminum film 22 is formed only on the barrier compound layer 14 by the VD method. Selection C using DMAH
The VD method is a method in which an aluminum film can be selectively deposited only on the conductive layer.

Next, as shown in FIG. 7D, an insulating film 7 having a thickness of about 800 nm is formed on the first aluminum film 22, and the insulating film 7 is formed on the source / drain region 4 with the first insulating film 7. The connection hole 8 reaching the aluminum film 22 is opened.

Next, as shown in FIG. 7E, DMAH
The second aluminum film 23 is formed in the connection hole 8 by the selective CVD method using. Further, the aluminum alloy film 16 is deposited on the second aluminum film 23 and the insulating film 7 by the sputtering method, and the aluminum alloy film 16 is patterned by the photolithography method to form the metal wiring.

FIG. 8 shows a sectional structure of a semiconductor device formed by the above-described manufacturing method. That is,
A gate oxide film 3, a gate electrode 5 made of a polysilicon film, and a source / drain region 4 are formed on a silicon substrate 1.
A cobalt silicide film 24 formed on the source / drain region 4 and the gate electrode 5, and a sidewall 9
And a MOS transistor having a. Then, nitrogen-oxygen- is formed on the entire surface of the cobalt silicide film 24.
Barrier compound layer 1 made of cobalt-silicon compound
4 is formed, and the first aluminum film 22 is further formed on the barrier compound layer 14 of the cobalt silicide film 24. Then, the first aluminum film 22 on the source / drain region 4 is formed on the insulating film 7 formed on the substrate.
A connection hole 8 reaching the above is formed, and a second aluminum film 23 as a buried layer is formed in the connection hole 8. In addition, the second aluminum film 23 and the insulating film 7
An aluminum alloy film 16 forming a metal wiring is formed on the top surface. That is, in the semiconductor device of this embodiment, the barrier compound layer 1 is formed on the entire surface of the cobalt silicide film 24 on the source / drain regions 4 and the gate electrode 5.
4 is formed and the cobalt silicide film 2 is formed.
4 is characterized in that an aluminum film (low resistance layer) having a low electric resistance is formed on the surface of No. 4.

Next, details of the structure of the barrier compound layer 14 of the semiconductor device obtained in the present embodiment and details of the reaction prevention effect of the first aluminum film 22 in the semiconductor device of the present embodiment will be described.

FIGS. 12A to 12C show a cobalt silicide film not plasma-processed, a cobalt silicide film plasma-processed in N 2 gas, and a cobalt silicide film plasma-processed in NH 3 gas, respectively. It is a figure which shows the concentration profile of each element obtained as a result of analyzing the area | region of the surface vicinity by XPS method.
However, in FIGS. 12A to 12C, the horizontal axis represents the depth from the surface, and the vertical axis represents the composition ratio of each element. Even in a cobalt silicide film that has not been plasma-treated, since heat treatment is performed at 750 ° C. in a nitrogen atmosphere during the formation of silicide, nitrogen is introduced near the surface, but the peak of the nitrogen concentration is at the surface position, and then the nitrogen is removed. The concentration is reduced and nitrogen is lost at a depth of about 2 nm. Also, the oxygen concentration is so small that it can be almost ignored at a depth of about 2 nm. On the other hand, N
In the cobalt silicide film plasma-processed in 2 gas or NH3 gas, a peak of nitrogen concentration is seen at a depth of about 2 nm from the surface.
In addition, the region where the oxygen concentration is high extends to a depth position of about 6 nm from the surface. That is, in the cobalt silicide film subjected to the plasma treatment in the nitrogen atmosphere, the barrier compound layer made of the nitrogen-oxygen-cobalt-silicon compound is formed from the surface to a depth position of about 6 nm. I understand.

In this embodiment, the cobalt silicide film 2 is used.
As a result of forming the barrier compound layer 14 in the vicinity of the surface of No. 4, the electric resistance of the cobalt silicide film 24 increased from 3.5Ω / □ to 3.6Ω / □, but the increase rate was 10% or less. It is a sufficiently low value that does not cause any particular problem in the operation.

FIG. 13 shows the dependence of the sheet resistance of various samples on the annealing temperature as a result of depositing an Al-0.5% Cu film as the first aluminum film 22 on the cobalt silicide film and performing the annealing process. FIG. 3 is a diagram showing the properties of the cobalt silicide film, which includes those that have been plasma-treated in N2 gas for 900 seconds, those that have been plasma-treated in NH3 gas for 900 seconds, and those that have not been plasma-treated. . The plasma treatment was performed by irradiating a cobalt silicide film having a thickness of 50 nm with nitrogen plasma in N2 gas or NH3 gas for 900 seconds. Then, in each of the samples, an Al-0.5% Cu alloy film was formed on the cobalt silicide film in an amount of about 200 n.
It is deposited to a thickness of m and then annealed for about 30 minutes.

As can be seen from the figure, in the sample not subjected to the plasma treatment, the increase of the sheet resistance value when annealed at 400 ° C. is not so large, but 43.
The sheet resistance value when annealed at 0 ° C. significantly increases. On the other hand, in each of the samples subjected to the plasma treatment, the increase of the resistance value is suppressed even if they are annealed at 400 ° C. and 430 ° C. That is, it can be seen that the barrier compound layer formed on the surface of the cobalt silicide film suppresses the reaction between the aluminum film and the cobalt silicide film. Generally, sintering is 400-450 ° C.
Since it is performed in a certain degree, such an effect of suppressing the sheet resistance value has significant significance in practical use.

The sample annealed at 430.degree.
As a result of PS analysis, Co2 Al19 or Co4 Al3 alloy was formed in the sample not treated with nitrogen plasma, whereas only peaks of Al and CoSi2 were observed in the sample treated with nitrogen plasma. That is, it was found from the X-ray analysis that the reaction between Al and CoSi2 was suppressed up to 430 ° C. by the nitrogen plasma treatment.

As described above, according to this embodiment, the surface of the metal silicide is subjected to the nitrogen plasma treatment to form the barrier compound layer of the nitrogen-oxygen-metal-silicon compound on the surface of the metal silicide film. I did so,
The subsequent heat treatment can effectively prevent the metal generated by the reaction between the metal silicide film and the aluminum alloy from entering the silicon substrate. In other words, unlike the conventional method, it is not necessary to apply a heat treatment at 800 ° C. or higher to the silicide film to form the barrier compound layer, so that boron in the source / drain regions is sucked up into the metal silicide film to saturate the P-channel transistor. There is no problem that the current value drops. Moreover, since the nitrogen plasma treatment is performed at a low temperature of 550 ° C. or less, it is possible to obtain an effect that the metal silicide film does not aggregate even for many kinds of metal silicide. That is, it is possible to increase the range of selection of the metal material forming the metal silicide.

(Other Embodiments) In the first or third embodiment, the metal wiring on the connection hole 8 is formed from the aluminum alloy film 16 and the Al—Ti compound layer 15, but the Al—Ti compound is used. Layer 15 may or may not be another metal film or compound thereof. further,
Another metal film may be laminated on the aluminum alloy film 16. Further, although the aluminum alloy containing silicon and copper is used as the aluminum alloy film 16, other aluminum alloy containing only silicon or other metal such as scandium or pure aluminum may be used. Further, copper or a copper alloy may be used instead of the aluminum alloy.

In each of the above embodiments, N2 gas was used as the gas containing nitrogen. First, NH3 gas or H2 gas was flowed to remove the natural oxide film on the surface of the metal silicide film.
After that, plasma may be generated in an atmosphere in which a slight amount of O2 gas is added to N2 gas to form a barrier compound layer made of a nitrogen-oxygen-titanium-silicon compound.
In that case, since the amount of oxygen can be controlled, the distribution of each element in the barrier compound layer can be made as close to the optimum state as possible, and the barrier having a lower contact resistance and a higher junction leak prevention effect than using a natural oxide film. A semiconductor device having a compound layer can be formed.

Even when the plasma treatment is performed using NH3 gas, by performing the plasma treatment at 550 ° C. or lower, the plasma treatment is performed under the conventional conditions of about 800 ° C. to form titanium nitride. Such a problem does not occur. Further, even when performing plasma treatment using NH3 gas, under the condition that a barrier compound layer made of a metal-silicon compound such as nitrogen-oxygen-titanium can be formed using a natural oxide film. It is possible to exert the effects of the present invention.

FIG. 14 is a TEM photograph showing the barrier compound layer formed on the surface of the silicide when the surface of the cobalt silicide is plasma-treated with NH3 gas. The plasma generation conditions are the same as the N2 gas plasma generation conditions described in the fifth embodiment. It can be seen that a nitrogen-oxygen-cobalt-silicon compound layer (amorphous layer) having a thickness of about 4-6 nm is formed. Further, as shown in the data of FIG. 13 already described, the increase in the sheet resistance due to the reaction between aluminum and cobalt silicide during the heat treatment is suppressed up to 430 ° C., which is about the same as when using N 2 gas. It can be seen that there is a reaction suppressing effect. The reason is that, as shown in FIG. 12 already described, when NH3 gas is used, the composition ratio of oxygen in the nitrogen-oxygen-cobalt-silicon compound layer is reduced and the composition ratio of nitrogen is increased. , It is presumed that the composition ratio of both is adjusted appropriately.

Needless to say, conditions other than the conditions in the above-mentioned embodiments can be used as the conditions for plasma formation.

In each of the above-described embodiments, the step of forming the nitrogen-oxygen-silicon compound layer by subjecting the surface of the titanium silicide film or the cobalt silicide film to the nitrogen plasma treatment is performed in the connection hole in the sputtering apparatus or the selective CVD apparatus. Immediately before depositing copper, aluminum, tungsten, or an alloy thereof, in the same apparatus,
Alternatively, it may be performed in the same apparatus immediately before forming copper, aluminum, tungsten or an alloy thereof on the barrier compound layer only by the selective CVD method.

In each of the above embodiments, titanium silicide is used as the metal silicide film, but cobalt silicide, nickel silicide, tantalum silicide, tungsten silicide, niobium silicide, palladium silicide, platinum silicide, molybdenum silicide, etc. may be used. Good.

Further, in each of the above embodiments, in the step of forming the barrier compound layer composed of the nitrogen-oxygen-metal-silicon compound, instead of exposing the surface of the metal silicide film to the plasma of the gas containing nitrogen, the metal silicide film is formed. By exposing the surface of the film to a gas containing nitrogen and at the same time irradiating it with ultraviolet rays or ionizing radiation, the energy of ultraviolet rays or the like is used to make the nitrogen-oxygen-metal surface on the surface of the metal silicide film at a low temperature of 550 ° C. or lower. -A barrier compound layer made of an intersilicon compound may be formed. Alternatively, instead of using plasma, by exposing the surface of the metal silicide film to an ion beam containing nitrogen, the energy of the ions is used to apply nitrogen-oxygen to the surface of the metal silicide film at a low temperature of 550 ° C. or lower. A barrier compound layer composed of a metal-silicon compound may be formed.

In the first to fourth embodiments, in the step of forming the barrier compound layer composed of the nitrogen-oxygen-metal-silicon compound, plasma treatment, irradiation with ultraviolet rays or the like, ion beam irradiation, etc. are performed. Whichever is selected, the potential for attracting nitrogen ions to the metal silicide side is preferably about 3 keV or less. The reason will be described. Generally, by analogy with the range of nitrogen ions in silicon, the potential is 1k.
In the case of eV, the nitrogen concentration in silicon has a depth of 3.8 n.
It peaks at the m position, and 10 at the 9.8 nm depth.
Reduce to%. When the potential is 3 keV,
The nitrogen concentration in silicon reaches a peak at a depth of 8.5 nm and decreases to 10% at a depth of 20.3 nm. Therefore, by suppressing the formation of the barrier compound layer to a depth of about 20 nm, which corresponds to 30% of the silicide film having a thickness of about 70 nm, it is possible to avoid an increase in sheet resistance and contact resistance.

The metal silicide film on which the barrier compound layer of the present invention is formed is not limited to the gate electrode and the source / drain regions shown in the above embodiments.
For example, when a polysilicon film is used as a component (especially an electrode) of a resistor or a capacitor, a silicide film on the polysilicon film may be formed, and even in that case, a metal silicide that contacts the upper wiring By forming the barrier compound layer of the nitrogen-oxygen-metal-silicon compound of the present invention on the surface of the film, the reaction between the buried layer and the metal silicide layer can be achieved without depositing the barrier metal in the connection hole. There is an advantage that it is possible to effectively prevent the metal or the like generated in step 2 from entering the electrode or other members through the electrode.

In the fifth embodiment, the barrier compound layer 14 made of nitrogen-oxygen-metal-silicon compound is formed on the entire surface of the cobalt silicide film 24 on the source / drain regions 4 and the gate electrode 5. The first aluminum film 22 and the titanium silicide film 6 are in contact with each other via the barrier compound layer 14, but instead of the first aluminum film 22, a metal containing aluminum,
The same effect is obtained when a film made of a metal containing copper and a metal containing tungsten is deposited. For example, even if a tungsten film is used instead of the first aluminum film 22, the presence of the barrier compound layer 14 causes the cobalt silicide and tungsten to react with each other in the subsequent heat treatment at 600 ° C. or higher, so that the metal is left in the silicon substrate. It is possible to effectively prevent the entry and the occurrence of a junction leak.

[0113]

As described above, according to the present invention,
In a semiconductor device in which a metal silicide film and an upper wiring are electrically connected via a buried layer in a connection hole formed in an insulating film on metal silicide, at least the metal silicide film serving as the bottom surface of the connection hole is formed. Since the barrier compound layer made of the nitrogen-oxygen-metal-silicon intermetallic compound is formed in the region near the surface, the reliability of the semiconductor substrate, etc. is not deteriorated by the barrier metal deposited in the connection hole. It is possible to prevent the invasion of the compound into the metal silicide film, thus keeping the sheet resistance value of the entire metal silicide film low,
In addition, it is possible to provide a semiconductor device that can suppress junction leakage and has a highly reliable buried layer in the connection hole, and a method for manufacturing the same.

[Brief description of drawings]

 )

FIG. 1 is a sectional view illustrating a manufacturing process of a semiconductor device according to a first embodiment.

FIG. 2 is a cross-sectional view of the semiconductor device according to the first embodiment.

FIG. 3 is a cross-sectional view of a semiconductor device according to a second embodiment.

FIG. 4 is a sectional view illustrating a manufacturing process of a semiconductor device according to a third embodiment.

FIG. 5 is a sectional view of a semiconductor device according to a third embodiment.

FIG. 6 is a sectional view of a semiconductor device according to a fourth embodiment.

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

FIG. 8 is a sectional view of a semiconductor device according to a fifth embodiment.

FIG. 9 is a diagram showing a result of elemental analysis in the depth direction on the surface of the titanium silicide film of the semiconductor device in the first embodiment.

FIG. 10 is a diagram comparing the junction leakage characteristics of a sample not subjected to nitrogen plasma treatment, a sample subjected to the treatment of the first embodiment, and a reference sample.

FIG. 11 is a diagram showing the annealing temperature dependence of the sheet resistance of various samples that were annealed by depositing an Al alloy after performing a nitrogen plasma treatment.

FIG. 12 shows CoSi when plasma nitriding is not performed, plasma nitriding is performed in an N 2 gas atmosphere, and plasma nitriding is performed in an NH 3 gas atmosphere.
It is a figure which shows the composition ratio of each element respectively obtained as a result of XPS analysis of the surface vicinity of 2 films.

FIG. 13 shows AlCu when plasma nitriding is not performed, plasma nitriding is performed in an N 2 gas atmosphere, and plasma nitriding is performed in an NH 3 gas atmosphere.
It is a figure which shows the temperature dependence of the sheet resistance of / CoSi2 structure.

FIG. 14 is a TEM photograph near the boundary of an AlCu / CoSi2 structure when plasma nitriding is performed in an NH3 gas atmosphere.

FIG. 15 is a cross-sectional view showing the manufacturing process of the conventional semiconductor device.

[Explanation of symbols]

 1 Silicon Substrate 2 Field Oxide Film 3 Gate Oxide Film 4 Source / Drain Region 5 Gate Electrode 6 Titanium Silicide Film 7 Insulating Film 8 Connection Hole 9 Sidewall 10 Anode 11 Cathode 12 Blocking Capacitor 13 High Frequency Power Supply 14 Barrier Compound Layer 15 Al-Ti Compound layer 16 Aluminum alloy film 17 Tungsten film 18 DC power supply Plz Nitrogen plasma 22 First aluminum film 23 Second aluminum film 24 Cobalt silicide film 25 Upper electrode 26 Lower electrode 27 High pass filter 28 Low pass filter 29 High frequency power supply 30 High frequency power supply

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H01L 21/336

Claims (23)

[Claims] 1. A semiconductor substrate, a metal silicide film formed on a part of the semiconductor substrate by siliciding a first metal, and a metal composed of a second metal formed on the metal silicide film. A semiconductor device comprising: a film; and a barrier compound layer formed in a region near the surface of the metal silicide film and formed of a nitrogen-oxygen-first metal-silicon compound. 2. The semiconductor device according to claim 1, wherein the barrier compound layer is formed in a region near the surface of the entire metal silicide film. 3. The semiconductor device according to claim 1, wherein the barrier compound layer has a thickness of at least a thickness sufficient to prevent diffusion of the second metal into the barrier compound layer. A semiconductor device having a film thickness of 30% or less. 4. The semiconductor device according to claim 1, wherein the barrier compound layer has a thickness in the range of 2 to 20 nm. 5. The semiconductor device according to claim 1, wherein the position where the concentration of nitrogen is maximum in the barrier compound layer is deeper than the position where the concentration of oxygen is maximum. A semiconductor device characterized by: 6. The semiconductor device according to claim 1, further comprising an insulating film formed on the metal silicide film, and a connection hole formed in a part of the insulating film and reaching the metal silicide film. The semiconductor device, wherein the metal film is a buried layer made of the second metal deposited in the connection hole. 7. The semiconductor device according to claim 1, wherein an insulating film formed on the metal silicide film, a connection hole formed in a part of the insulating film and reaching the metal silicide film, and the connection. A semiconductor device further comprising a buried layer made of a third metal deposited in the hole. 8. The semiconductor device according to claim 1, 2, 3, 4, 5, 6 or 7, wherein the first metal is titanium, cobalt, nickel, tantalum, tungsten, niobium, palladium, platinum and molybdenum. A semiconductor device characterized by being any one of the above. 9. The semiconductor device according to claim 1, 2, 3, 4, 5, 6 or 7, wherein the second metal is any of a metal containing aluminum, a metal containing copper and a metal containing tungsten. A semiconductor device characterized by being one. 10. A first metal silicide film made of a compound of a first metal and silicon is formed on a semiconductor substrate.
And in a neutral or oxidizing atmosphere, the surface of the metal silicide film is irradiated with ions containing nitrogen, and a region near the surface of the metal silicide film is exposed to the nitrogen-oxygen-first metal-silicon compound. A second step of forming a barrier compound layer made of, and a second step on the barrier compound layer of the metal silicide film.
And a third step of depositing the metal to form a metal film. 11. The method of manufacturing a semiconductor device according to claim 10, wherein an insulating film is formed on the metal silicide film after the first step and before the second step, And a step of selectively removing a part of the insulating film to form a connection hole reaching the metal silicide film. In the second step, the connection in the region near the surface of the metal silicide film is formed. A method of manufacturing a semiconductor device, comprising forming the barrier compound layer in a region exposed at the bottom of a hole, and filling the inside of the connection hole with the second metal in the third step. 12. The method of manufacturing a semiconductor device according to claim 10, wherein after the second step, a step of forming an insulating film on the barrier compound layer of the metal silicide film; A step of selectively removing a portion to form a connection hole reaching the barrier compound layer, and in the third step, the second metal is deposited in the connection hole. Of manufacturing a semiconductor device. 13. The method of manufacturing a semiconductor device according to claim 12, wherein after the third step, a step of forming an insulating film on the barrier compound layer of the metal silicide film; And a step of selectively removing a portion to form a connection hole reaching the barrier compound layer, and a step of depositing a third metal in the connection hole to form a buried layer. A method for manufacturing a semiconductor device, comprising: 14. The method of manufacturing a semiconductor device according to claim 10, 11, 12 or 13, wherein in the second step, plasma is generated by arranging a lower electrode as a cathode and an upper electrode as an anode in a chamber. The barrier compound layer is formed by exposing the metal silicide film to plasma of a gas containing nitrogen in a state where the semiconductor substrate is placed on the lower electrode in the chamber using an apparatus. Manufacturing method of semiconductor device. 15. The method of manufacturing a semiconductor device according to claim 10, 11, 12 or 13, wherein in the second step, the surface of the metal silicide film is exposed to a gas containing nitrogen to remove ultraviolet rays and ionizing radiation. A method for manufacturing a semiconductor device, characterized in that the barrier compound layer is formed by irradiating either one of them. 16. The method of manufacturing a semiconductor device according to claim 10, 11, 12 or 13, wherein in the second step, the surface of the metal silicide film is exposed to an ion beam containing nitrogen to thereby form the barrier compound. A method of manufacturing a semiconductor device, which comprises forming a layer. 17. The method of claim 10, 11, 12, 13, 1.
4. The method for manufacturing a semiconductor device according to 4, 15, or 16, wherein the second step is performed at 550 ° C. or lower. 18. The method according to claim 10, 11, 12, 13, 1.
4. The method for manufacturing a semiconductor device according to 4, 15, or 16, wherein in the second step, N2 gas is used as the gas containing nitrogen. 19. The method according to claim 10, 11, 12, 13, 1.
4, 15, 16, 17 or 18, a step of removing a natural oxide film on the metal silicide film by flowing a gas containing hydrogen before the second step. The semiconductor device manufacturing method further comprises the step of adding a gas containing oxygen in the second step. 20. Claims 10, 11, 12, 13, 1
4. The method for manufacturing a semiconductor device according to 4, 15, or 16, wherein in the second step, ions containing nitrogen are introduced into the metal silicide film with an ion energy of 3 keV or less. . 21. Claims 11, 11, 12, 13, 1
4, 15, 16, 17, 18, 19 or 20, wherein in the first step, titanium, cobalt, nickel, tantalum, tungsten, palladium, platinum and molybdenum are used as the metal silicide film. A method of manufacturing a semiconductor device, comprising forming one of the silicide films. 22. Claims 10, 11, 12, 13, 1
4, 15, 16, 17, 18, 19 or 20, wherein in the third step, a metal containing aluminum, a metal containing copper and a metal containing tungsten are used by a CVD method. A method for manufacturing a semiconductor device, characterized in that any one of them is deposited. 23. Claims 10, 11, 12, 13, 1
4, 15, 16, 17, 18, 19 or 20, wherein in the third step, the metal film is formed of Al-T by continuously sputtering titanium and an aluminum alloy.
A method for manufacturing a semiconductor device, which comprises an i compound layer and an aluminum alloy film.