JP4497339B2 - Ta-based film forming material and Ta-based film forming method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a conductive Ta-based film forming material, a conductive Ta-based film forming method, and a ULSI in which a copper wiring film is formed on a conductive Ta-based film.
[0002]
[Problems to be solved by the invention]
At present, the progress in the semiconductor field is remarkable, and the LSI is moving from ULSI. In order to improve the processing speed of signals, miniaturization is progressing. In particular, the conductive portion (wiring) for transmitting an electrical signal is required to be thin.
[0003]
However, if the wiring is made thinner, the electric resistance naturally becomes higher.
[0004]
Therefore, a lower resistance wiring material has been demanded. For example, it has moved from W wiring to Al wiring. In the next generation, Cu wiring films are attracting attention.
[0005]
However, when Cu is used, the diffusion of Cu into the silicon substrate is severe.
[0006]
Therefore, it is difficult to use Cu as a wiring film material as it is.
[0007]
Therefore, as a conceivable means, a diffusion prevention film (barrier film) is provided on the substrate, and a copper film is formed thereon.
[0008]
As a material for the barrier film, metal tantalum, tantalum carbide, tantalum nitride, tantalum nitride, tantalum nitride nitride, and tantalum nitride nitride are listed as candidates.
[0009]
By the way, with the miniaturization of ULSI, the copper wiring width is required to be 0.18 μm or less. For this reason, the conductive Ta-based film as a barrier film is required to be thin, and it has become necessary to form a conductive Ta-based film by chemical vapor deposition (CVD).
[0010]
In other words, although it is most advantageous to form a film by CVD, only a few examples have been reported to form a conductive Ta-based film by CVD. And satisfactory results have not been obtained.
[0011]
Accordingly, a first problem to be solved by the present invention is to provide a liquid conductive Ta-based film forming material that is easy to use.
[0012]
A second problem to be solved by the present invention is to provide a method for forming a conductive Ta-based film using the conductive Ta-based film forming material.
[0013]
A third problem to be solved by the present invention is to provide a ULSI in which a copper wiring film is formed on a conductive Ta-based film as a barrier film formed by the conductive Ta-based film forming method. It is.
[0014]
[Means for Solving the Problems]
The first problem is that C ₂ H ₅ N = Ta [N (C ₂ H ₅ ) ₂ ] ₃ ,
[N (C ₂ H ₅ ) ₂ ] ₄ Ta
It solves by the conductive Ta type | system | group film formation material characterized by including these.
[0015]
C ₂ H ₅ N = Ta [N (C ₂ H ₅ ) ₂ ] ₃
[N (C ₂ H ₅ ) ₂ ] ₄ Ta,
This is solved by a conductive Ta-based film forming material comprising a hydrocarbon solvent having 5 to 40 carbon atoms.
[0016]
C ₂ H ₅ N = Ta [N (C ₂ H ₅ ) ₂ ] ₃
[N (C ₂ H ₅ ) ₂ ] ₄ Ta,
This is solved by a conductive Ta-based film forming material characterized by containing an amine-based solvent having 2 to 40 carbon atoms.
[0017]
C ₂ H ₅ N = Ta [N (C ₂ H ₅ ) ₂ ] ₃
[N (C ₂ H ₅ ) ₂ ] ₄ Ta,
This is solved by a conductive Ta-based film forming material comprising a hydrocarbon solvent having 5 to 40 carbon atoms and an amine solvent having 2 to 40 carbon atoms.
[0018]
The conductive Ta-based film formed of the conductive Ta-based film forming material is a film containing at least Ta and N as main components. Further, it is a film containing at least Ta, N and C as main components. In addition, for example, Si may be included.
[0019]
The second problem is a method of forming a conductive Ta-based film,
Providing the conductive Ta-based film forming material on a substrate;
The conductive Ta-based film forming method includes the step of decomposing the conductive Ta-based film forming material provided on the substrate to form a conductive Ta-based film.
[0020]
Also, a method of forming a conductive Ta-based film by CVD,
This is solved by a method for forming a conductive Ta-based film, comprising the step of decomposing the conductive Ta-based film forming material and forming a conductive Ta-based film on a substrate.
[0021]
Furthermore, the problem is solved by a method for forming a conductive Ta-based film, comprising the step of heating a substrate on which the conductive Ta-based film is formed.
[0022]
The conductive Ta-based film forming material is decomposed, for example, by heating. Alternatively, it is performed by light irradiation. Alternatively, it is performed by plasma irradiation. The decomposition of the conductive Ta-based film forming material is performed in a reducing atmosphere.
[0023]
The third problem is solved by a ULSI characterized in that a copper wiring film is formed on a conductive Ta-based film formed by using the conductive Ta-based film forming method.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
The conductive Ta-based film forming material according to the present invention (particularly, the conductive Ta-based film forming material serving as a barrier film for copper) is C ₂ H ₅ N = Ta [N (C ₂ H ₅ ) ₂ ] ₃ , [N (C ₂ H ₅ ) ₂ ] ₄ Ta. In particular, C ₂ H ₅ N = Ta [N (C ₂ H ₅ ) ₂ ] ₃ , [N (C ₂ H ₅ ) ₂ ] ₄ Ta, and a hydrocarbon solvent having 5 to 40 carbon atoms are included. Or, C ₂ H ₅ N = Ta [N (C ₂ H ₅ ) ₂ ] ₃ , [N (C ₂ H ₅ ) ₂ ] ₄ Ta, and an amine solvent having 2 to 40 carbon atoms are included. Alternatively, C ₂ H ₅ N = Ta [N (C ₂ H ₅ ) ₂ ] ₃ , [N (C ₂ H ₅ ) ₂ ] ₄ Ta, a hydrocarbon solvent having 5 to 40 carbon atoms and 2 carbon atoms. To 40 amine solvents. The mixing ratio of C ₂ H ₅ N = Ta [N (C ₂ H ₅ ) ₂ ] ₃ and [N (C ₂ H ₅ ) ₂ ] ₄ Ta is the former: latter = 1: 1-15. The conductive Ta-based film formed of the conductive Ta-based film forming material is a film containing at least Ta and N as main components. Further, it is a film containing at least Ta, N and C as main components. In addition, for example, Si may be included.
[0025]
The method for forming a conductive Ta-based film according to the present invention is a method for forming a conductive Ta-based film, and the above-mentioned conductive Ta-based film forming material is applied on a substrate by means such as dipping means or spray means. And a step of decomposing the conductive Ta-based film forming material provided on the substrate to form a conductive Ta-based film. Alternatively, it is a method of forming a conductive Ta-based film by CVD, comprising a step of decomposing the conductive Ta-based film forming material and forming a conductive Ta-based film on a substrate. Further, the method includes a step of heating the substrate on which the conductive Ta-based film is formed. The conductive Ta-based film forming material is decomposed, for example, by heating. Alternatively, it is performed by light irradiation. Alternatively, it is performed by plasma irradiation. The decomposition of the conductive Ta-based film forming material is performed in a reducing atmosphere.
[0026]
The ULSI according to the present invention is obtained by forming a copper wiring film on a conductive Ta-based film formed by using the conductive Ta-based film forming method.
[0027]
Hereinafter, the present invention will be described with specific examples.
[0028]
[Example 1]
FIG. 1 is a schematic view of a CVD apparatus for forming a conductive Ta-based film.
[0029]
That is, a Ta-based film was formed using the apparatus of FIG. In FIG. 1, 1a, 1b and 1c are containers, 2 is a vaporizer, 3 is a heater, 4 is a decomposition reaction furnace, 5 is a substrate, 6 is a reaction gas (for example, hydrogen, hydrogen plasma, ammonia, silane, etc.), 7 is a gas flow controller, and 8 is a liquid flow controller.
[0030]
A mixture of C ₂ H ₅ N = Ta [N (C ₂ H ₅ ) ₂ ] ₃ and [N (C ₂ H ₅ ) ₂ ] ₄ Ta (the former: the latter = 1: 8) is put in the container 1c. ing. There is nothing in the containers 1a and 1b. The Ta compound mixture was bubbled with helium, vaporized, and deposited on the Si substrate 5.
[0031]
The film forming conditions at this time are as follows.
[0032]
Substrate temperature: 200-450 ° C
Film forming pressure: 0.2 to 1.5 torr
Vaporization temperature: 60 ° C
Reaction gas: Hydrogen gas Carrier gas: He
The film formed on the Si substrate 5 in this manner was a TaCN amorphous film. And the film thickness was 0.02-0.3 micrometer, and resistance was 4000 microhm * cm.
[0033]
[Example 2]
A mixture of C ₂ H ₅ N = Ta [N (C ₂ H ₅ ) ₂ ] ₃ and [N (C ₂ H ₅ ) ₂ ] ₄ Ta (the former: the latter = 1: 8) is placed in the container 1a. ing. There is nothing in the containers 1b and 1c. The Ta compound mixture was controlled and transported by the liquid flow rate controller 8, vaporized by the vaporizer 2, and deposited on the Si substrate 5.
[0034]
The film forming conditions at this time are as follows.
[0035]
Substrate temperature: 200-450 ° C
Film forming pressure: 0.2 to 1.5 torr
Vaporization temperature: 50-70 ° C
Reaction gas: Hydrogen gas Carrier gas: He
The film formed on the Si substrate 5 in this manner was a TaCN amorphous film. And the film thickness was 0.01-0.3 micrometer, and resistance was 4000-10000 microhm * cm.
[0036]
[Example 3]
C ₂ H ₅ N = Ta [N (C ₂ H ₅ ) ₂ ] ₃ and [N (C ₂ H ₅ ) ₂ ] ₄ Ta mixture (former: latter = 1: 8) dissolved in xylene Is placed in the container 1a. There is nothing in the containers 1b and 1c. The Ta compound mixture was controlled and transported by the liquid flow rate controller 8, vaporized by the vaporizer 2, and deposited on the Si substrate 5.
[0037]
The film forming conditions at this time are as follows.
[0038]
Substrate temperature: 200-500 ° C
Film forming pressure: 0.2 to 1.5 torr
Vaporization temperature: 50-70 ° C
Reaction gas: Hydrogen gas Carrier gas: He
The film formed on the Si substrate 5 in this manner was a TaCN amorphous film. And the film thickness was 0.01-0.3 micrometer, and resistance was 4000-10000 microhm * cm.
[0039]
[Example 4]
A solution prepared by dissolving a mixture of C2 H5 N = Ta [N (C2 H5) 2] 3 and [N (C2 H5) 2] 4 Ta (former: latter = 1: 8) in cycloheptatriene is used as a container 1a. It is put in. There is nothing in the containers 1b and 1c. The Ta compound mixture was controlled and transported by the liquid flow rate controller 8, vaporized by the vaporizer 2, and deposited on the Si substrate 5.
[0040]
The film forming conditions at this time are as follows.
[0041]
Substrate temperature: 200-500 ° C
Film forming pressure: 0.2 to 1.5 torr
Vaporization temperature: 50-70 ° C
Reaction gas: Hydrogen plasma carrier gas: Hydrogen gas The film thus formed on the Si substrate 5 was an amorphous film of TaCN. And the film thickness was 0.01-0.3 micrometer, and resistance was 4000-10000 microhm * cm.
[0042]
[Example 5]
C2 H5 N = Ta [N (C2 H5) 2] 3 and [N (C2 H5) 2] 4 Ta A solution (the former: the latter = 1: 8) dissolved in toluene is placed in the container 1a. It has been. There is nothing in the containers 1b and 1c. The Ta compound mixture was controlled and transported by the liquid flow rate controller 8, vaporized by the vaporizer 2, and deposited on the Si substrate 5.
[0043]
The film forming conditions at this time are as follows.
[0044]
Substrate temperature: 150-450 ° C
Film forming pressure: 0.2 to 1.5 torr
Vaporization temperature: 50-130 ° C
Reaction gas: Ammonia gas Carrier gas: Nitrogen gas The film thus formed on the Si substrate 5 was an amorphous film of TaCN. And the film thickness was 0.01-0.3 micrometer, and resistance was 4000-10000 microhm * cm.
[0045]
[Example 6]
100 parts by weight of a mixture of C ₂ H ₅ N = Ta [N (C ₂ H ₅ ) ₂ ] ₃ and [N (C ₂ H ₅ ) ₂ ] ₄ Ta (the former: latter = 1: 8) is dissolved in toluene. The solution thus prepared is placed in the container 1a. The container 1c contains ethyl azide. There is nothing in the container 1b. The Ta compound mixture was controlled and transported by the liquid flow rate controller 8, vaporized by the vaporizer 2, and deposited on the Si substrate 5.
[0046]
The film forming conditions at this time are as follows.
[0047]
Substrate temperature: 300-500 ° C
Film forming pressure: 0.2 to 1.5 torr
Vaporization temperature: 50-70 ° C
Reaction gas: None Carrier gas: Nitrogen gas The film thus formed on the Si substrate 5 was an amorphous film of TaCN. And the film thickness was 0.01-0.3 micrometer, and resistance was 4000-10000 microhm * cm.
[0048]
[Example 7]
C ₂ H ₅ N = Ta [N (C ₂ H ₅ ) ₂ ] ₃ and [N (C ₂ H ₅ ) ₂ ] ₄ Ta mixture (former: latter = 1: 8) dissolved in diethylamine Is placed in the container 1a. There is nothing in the containers 1b and 1c. The Ta compound mixture was controlled and transported by the liquid flow rate controller 8, vaporized by the vaporizer 2, and deposited on the Si substrate 5.
[0049]
The film forming conditions at this time are as follows.
[0050]
Substrate temperature: 300-500 ° C
Film forming pressure: 0.2 to 1.5 torr
Vaporization temperature: 50-70 ° C
Reaction gas: Ammonia gas Carrier gas: Nitrogen gas The film thus formed on the Si substrate 5 was an amorphous film of TaCN. And the film thickness was 0.01-0.3 micrometer, and resistance was 4000-10000 microhm * cm.
[0051]
[Example 8]
A mixture of C ₂ H ₅ N = Ta [N (C ₂ H ₅ ) ₂ ] ₃ and [N (C ₂ H ₅ ) ₂ ] ₄ Ta (former: latter = 1: 8) is mixed with toluene and heptane. A solution dissolved in the mixed solution is placed in the container 1a. There is nothing in the containers 1b and 1c. The Ta compound mixture was controlled and transported by the liquid flow rate controller 8, vaporized by the vaporizer 2, and deposited on the Si substrate 5.
[0052]
The film forming conditions at this time are as follows.
[0053]
Substrate temperature: 300-500 ° C
Film forming pressure: 0.2 to 1.5 torr
Vaporization temperature: 50-70 ° C
Reaction gas: Silane gas Carrier gas: Nitrogen gas The film thus formed on the Si substrate 5 was an amorphous film of SiTaCN. And the film thickness was 0.01-0.3 micrometer, and resistance was 4000-10000 microhm * cm.
[0054]
[Example 9]
C ₂ H ₅ N = Ta [N (C ₂ H ₅ ) ₂ ] ₃ and [N (C ₂ H ₅ ) ₂ ] ₄ Ta mixture (former: latter = 1: 8) dissolved in nonane Is placed in the container 1a. There is nothing in the containers 1b and 1c. The Ta compound mixture was controlled and transported by the liquid flow rate controller 8, vaporized by the vaporizer 2, and deposited on the Si substrate 5.
[0055]
The film forming conditions at this time are as follows.
[0056]
Substrate temperature: 300-500 ° C
Film forming pressure: 0.2 to 1.5 torr
Vaporization temperature: 50-70 ° C
Reaction gas: Silane gas Carrier gas: Nitrogen gas The film thus formed on the Si substrate 5 was an amorphous film of SiTaCN. And the film thickness was 0.01-0.3 micrometer, and resistance was 4000-10000 microhm * cm.
[0057]
[Example 10]
The Si substrate provided with the TaCN thin film prepared in the above example was heated to 160 ° C.
[0058]
Thereafter, a heptadecane solution (0.2 mol / l) of hexafluoroacetylacetone copper trimethylvinylsilane (HfacCu: TMVS) was poured onto the Si substrate. After thermal decomposition for 20 seconds, the mixture was cooled, the solution was poured out, and the inside of the container was washed three times with normal hexane, and then the Si substrate was taken out.
[0059]
The Si substrate initially had a silver luster, but after removal, it changed to a copper-like red and gold luster.
[0060]
Then, when a cross section of the Si substrate having a red gold gloss was observed with an electron microscope, deposits were observed from the surface to a depth of about 0.5 μm. When the deposits of this cross-sectional image were provided for elemental analysis, a thin film mainly containing Cu and Ta, C, and N is from the surface to about 0.5 μm, and pure silicon is below this thin film I understood.
[0061]
From this result, it was confirmed that copper was not diffused in the Si substrate.
[0062]
[Comparative Example 1]
The Si substrate not provided with the TaCN thin film was heated to 160 ° C.
[0063]
Thereafter, HfacCu: TMVS heptadecane solution (0.2 mol / l) was poured onto the Si substrate. After thermal decomposition for 20 seconds, the mixture was cooled, the solution was poured out, and the inside of the container was washed three times with normal hexane, and then the Si substrate was taken out.
[0064]
The surface of the Si substrate had changed to a copper-like red gold luster.
[0065]
Then, when the cross section of the Si substrate having a red gold gloss was observed with an electron microscope, deposits were observed from the surface to a depth of about 0.4 μm. When the deposit of this cross-sectional image was provided for elemental analysis, it was found that Cu up to about 0.4 μm from the surface, Cu—Si up to a depth of 2 μm from there, and pure silicon underneath.
[0066]
From this result, it was confirmed that copper was diffusing in the Si substrate.
[0067]
Example 11
A copper thin film was formed on the Si substrate provided with the TaCN thin film prepared in the above example by CVD using a TMVS solution of HfacCu: TMVS as a raw material. The Si substrate initially had a silver luster, but after removal, it changed to a copper-like red and gold luster.
[0068]
And when the cross section of the Si substrate whose surface was red gold gloss was observed with the electron microscope, the deposit was observed to the depth of about 0.8 micrometer from the surface. When the deposit of this cross-sectional image was provided for elemental analysis, a thin film mainly composed of Cu and Ta, C and N is from the surface to about 0.8 μm, and the bottom of this thin film is pure silicon I understood.
[0069]
From this result, it was confirmed that copper was not diffused in the Si substrate.
[0070]
[Comparative Example 2]
A copper thin film was formed on a Si substrate not provided with a TaCN thin film by CVD using a TMVS solution of HfacCu: TMVS as a raw material.
[0071]
The surface of the Si substrate had changed to a copper-like red gold luster.
[0072]
Then, when a cross section of the Si substrate having a red gold gloss was observed with an electron microscope, deposits were observed from the surface to a depth of about 0.5 μm. When the deposit of this cross-sectional image was provided for elemental analysis, it was found that Cu up to about 0.5 μm from the surface, Cu—Si up to a depth of 2 μm from there, and pure silicon underneath.
[0073]
From this result, it was confirmed that copper was diffusing in the Si substrate.
[0074]
【The invention's effect】
According to the present invention in which C ₂ H ₅ N = Ta [N (C ₂ H ₅ ) ₂ ] ₃ and [N (C ₂ H ₅ ) ₂ ] ₄ Ta are used in combination, they are not used in combination. ₂ H ₅ N = Ta [N (C ₂ H ₅ ) ₂ ] ₃ alone or higher quality than when only [N (C ₂ H ₅ ) ₂ ] ₄ Ta is used A conductive Ta-based film is obtained.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a CVD apparatus.

Claims (10)

A material for forming a conductive Ta-based film by chemical vapor deposition,
C ₂ H ₅ N = Ta [N (C ₂ H ₅ ) ₂ ] ₃ ;
[N (C ₂ H ₅ ) ₂ ] ₄ Ta ,
Conductive Ta film forming material which comprises a hydrocarbon solvent <br/> 5-40 carbon atoms. A material for forming a conductive Ta-based film by chemical vapor deposition,
C ₂ H ₅ N = Ta [N (C ₂ H ₅ ) ₂ ] ₃ ;
[N (C ₂ H ₅ ) ₂ ] ₄ Ta,
A conductive Ta-based film forming material comprising an amine-based solvent having 2 to 40 carbon atoms . The conductive Ta-based film forming material according to claim 1 or 2, wherein the conductive Ta-based film is a film containing at least Ta and N as main components . 3. The conductive Ta-based film forming material according to claim 1, wherein the conductive Ta-based film is a film containing at least Ta, N, and C as main components. A method of forming a conductive Ta-based film by chemical vapor deposition,
Decomposing the claims 1 to 4 either conductive Ta film forming material, conductive Ta film forming method comprising <br/> by comprising a step of forming a conductive Ta film on the substrate . The method for forming a conductive Ta-based film according to claim 5, further comprising a step of heating the substrate on which the conductive Ta-based film is formed. Conductive Ta film degradation forming material conductive Ta film forming method according to claim 5, characterized in <br/> be performed by heating. The method for forming a conductive Ta-based film according to claim 5 , wherein the decomposition of the conductive Ta-based film forming material is performed by light irradiation . The method for forming a conductive Ta-based film according to claim 5 , wherein the decomposition of the conductive Ta-based film forming material is performed by plasma irradiation . The method for forming a conductive Ta-based film according to any one of claims 5 to 9, wherein the decomposition of the conductive Ta-based film forming material is performed in a reducing atmosphere .

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