KR102276421B1 - Copper base film-forming method - Google Patents

Abstract

(Project) To provide a technology capable of easily forming a high-quality copper film because the decomposition temperature in the supercritical fluid is low and the quality of the copper film does not deteriorate due to the mixing of C and O.
(Solution) The present invention is a method for forming a copper-based film in a gas phase in a supercritical fluid, by dissolving (N,N'-diisopropylpropionamidinate) copper dimers in a gaseous phase It is a method of forming a copper-based film by depositing copper on the

Description

Copper-based film formation method {COPPER BASE FILM-FORMING METHOD}

The present invention relates to a technology for forming a copper-based film.

BACKGROUND ART Films such as copper or copper alloy (also simply referred to as copper) are used in various fields. For example, it is used as a wiring film for ULPI (ultra large scale integration). Copper wiring is manufactured by electroplating, sputtering, chemical vapor deposition, atomic layer deposition, and SFC. )) method (supercritical fluid deposition method) is proposed. Electrolytic plating and sputtering have been put to practical use. However, when the wiring width becomes nanoscale, it is said that it is difficult to use an electrolytic plating method or a sputtering method. For film formation where the opening is a deep groove or hole having a width of a nanoscale, the DCV method, the ALD method, or the SCD method is expected. In the DCVD method or the ALD method, volatilization (vaporization) of the raw material compound is essential. In the SCD method, the raw material compound needs to be dissolved in the supercritical fluid, and vaporization is not required. In this regard, the requirements for the raw material compound used in the DCD method or the ALD method and the raw material compound used in the SCD method are different.

The following literature is known as a copper film formation technique by the SCD method.

[Non-Patent Document 1] Jpn.J.Appl.Phys.2005,44,L1199-L1202.Takeshi Momose, Masakazu Sugiyama and Yukihiro Shimogaki "Precursor Evaluation for Cu-Supercritical Fluid Deposition Based on Adhesion Properties and Surface Morphology" [Non-Patent Document 2] Journal of Electrochemical Society, 2009,156,6, H443-H447. Masahiro Matsubara, Michiru Hirose, Kakeru Tamai, Yukihiro Shimogaki and Eiichi Kondoh "Kinetics of Deposition of Cu Thin Films in Supercritical Carbon Dioxide Solutions from a F-Free Copper(II)β-Diketone Complex"

In the above document, hexafluoroacetylacetonato complex of copper [Cｕ(ｈｆａｃ) _{2 ] and βｂ(ｄｉ) 2 of} diisobutylmethanato complex [Cｕ(ｄｉ) 2] A diketone copper complex (β-diketone 銅錯物) was used, and deposition of copper (copper film formation) in a supercritical fluid of _{CO 2 was achieved.} That is, the copper film was formed by the SCD method.

However, the obtained copper film had a large amount of impurities. An investigation into this cause was made. As a result, it has been known that a high temperature is required for decomposition in a supercritical fluid of compounds such as _{Cc(ｈｆａｃ) 2} and CＣｕ(ｄｉｂm) _{2 .} As a result, it was speculated that the β-diketone of the ligand was decomposed and C and O were mixed in the copper film. In addition, _{when C(a) 2} was used, F was detected in the copper film. Since the copper film contained F, the adhesion between the base film and the copper film was inferior.

For this reason, it has been known that the raw material compound used in the SCD method does not need only to be dissolved in a supercritical fluid.

Accordingly, the problem to be solved by the present invention is to solve the above problems. In particular, it is to provide a technology capable of easily forming a high-quality copper film because the decomposition temperature in the supercritical fluid is low, and there is no problem that the quality of the copper film is deteriorated due to the mixing of C and O.

Investigation for solving the above-mentioned subject was vigorously promoted by the present inventors. As a result, when the compound represented by the following general formula [I] (copper amidinate complex) is dissolved in the supercritical fluid and the deposition reaction is performed in the supercritical fluid as it is, the deposition film (堆積)膜), it has been found that a small amount of impurities (C, O) mixed and a high-quality Cu-based film can be stably formed in nanoscale grooves or pores.

The present invention was made based on the above knowledge.

The present invention is a material for forming a copper-based film on a substrate by decomposition of a compound dissolved in a supercritical fluid, wherein the compound is a compound represented by the following general formula [I] A film-forming material is proposed.

The present invention is a method for forming a copper-based film on a gas phase in a supercritical fluid, dissolving a compound represented by the following general formula [I] in a supercritical fluid and depositing copper on the gas phase to form a copper-based film A method for forming a copper-based film is proposed.

general formula [I]

[R ¹ , R ² , R ³ , R ⁴ , R ⁵ , and R ⁶ are hydrocarbon groups having 1 to 10 carbon atoms. R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ may all be the same or different.]

The amount of impurities such as C and O mixed is small, and a high-quality Cu-based film can be stably formed in nanoscale grooves or holes.

1 is a schematic diagram of a SCD device.
2 is an electron microscope photograph.
3 is an electron microscope photograph.

A first aspect of the present invention is a method for forming a copper-based film. This method is a method of forming a copper-based film by dissolving a compound represented by the following general formula [I] in a supercritical fluid and depositing copper on a substrate.

The second aspect of the present invention is a copper-based film-forming material. This material is a material for forming a copper-based film on a substrate by decomposition of a compound dissolved in a supercritical fluid. The compound is a compound represented by the following general formula [I].

general formula [I]

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , and R ⁶ are a hydrocarbon group having 1 to 10 carbon atoms. The hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The hydrocarbon group may have a substituent and may not have a substituent. A substituent may be a functional group provided with S. All of said R ¹ , R ² , R ³ , R ⁴ , R ⁵ , and R ⁶ may be the same or different. Preferably R ¹ , R ² , R ⁴ , R ⁵ and R ³ , R ⁶ are different.

The compound represented by the said general formula [I] is a solid thing in many cases. In the case of a solid, rather than supplying the compound as it is in the supercritical fluid, it is preferable to supply the compound in the form of dissolving it in a solvent (solution form) into the supercritical fluid so that the compound is dissolved in the supercritical fluid. The solvent may be any as long as it does not adversely affect the compound and the supercritical fluid. Preferred solvents include, for example, pentane, hexane, heptane, octane, nonane, decane, acetone, methylisobutylketone, One or two or more selected from the group of diethylether, tetrahydrofuran, and dioxane. The hydrocarbon may be any type of a straight-chain aliphatic hydrocarbon, a branched-chain aliphatic hydrocarbon, and a cyclic hydrocarbon.

The most preferable compound as a compound represented by the general formula [I] is that R ¹ , R ² , R ⁴ , R ⁵ is an iso-propyl group, R ³ , R ⁶ is an ethyl group (ethyl)基) (ie, (N,N'-diisopropylpropionamidinate) copper dimer (量体)).

As a compound preferable as a compound represented by the said general formula [I], said R ¹ , R ² , R ⁴ , R ⁵ is an iso-propyl group, said R ³ , R ⁶ is a methyl group (that is, (N ,N'-diisopropylacetamidinate (copper dimer) is the case.

As a compound preferable as a compound represented by the said general formula [I], said R ¹ , R ² , R ⁴ , R ⁵ is an iso-propyl group, said R ³ , R ⁶ is an n-butyl group (n-butyl group) (i.e., copper amidinate).

As for the compound preferable as a compound represented by the said general formula [I], when said R<^1> , R<^2> , R<^4> , R<^5> is an n-propyl group, and said R<^3> , R<^6> is a methyl group (ie, copper amidinate) to be.

As for the compound preferable as a compound represented by the said general formula [I], when said R<^1> , R<^2> , R<^4> , R<^5> is n-propyl group, and said R<^3> , R<^6> is an ethyl group (that is, copper amidinate) to be.

As for the compound preferable as a compound represented by the said general formula [I], said R<^1> , R<^2> , R<^4> , R<^5> is n-propyl group, said R<^3> , R<^6> is n-butyl group (ie, copper amidinate) ) is the case.

As for the compound preferable as a compound represented by the said general formula [I], when said R<^1> , R<^2> , R<^4> , R<^5> is an n-butyl group, and said R<^3> , R<^6> is a methyl group (ie, copper amidinate) to be.

As for the compound preferable as a compound represented by the said general formula [I], when said R<^1> , R<^2> , R<^4> , R<^5> is n-butyl group, and said R<^3> , R<^6> is an ethyl group (ie, copper amidinate) to be.

As for the compound preferable as a compound represented by the said general formula [I], when said R<^1> , R<^2> , R<^4> , R<^5> is an iso- butyl group, and said R<^3> , R<^6> is a methyl group (ie, copper amidinate) to be.

As for the compound preferable as a compound represented by the said general formula [I], when said R<^1> , R<^2> , R<^4> , R<^5> is an iso- butyl group, and said R<^3> , R<^6> is an ethyl group (ie, copper amidinate) to be.

As for a compound preferable as a compound represented by the said general formula [I], said R ¹ , R ² , R ⁴ , R ⁵ is an iso-butyl group, said R ³ , R ⁶ is an n-butyl group (ie, copper amidinate) ) is the case.

As for a compound preferable as a compound represented by the said general formula [I], when said R<^1> , R<^2> , R<^4> , R<^5> is a sec-butyl group, and said R<^3> , R<^6> is a methyl group (that is, copper amidinate) to be.

As a compound preferable as a compound represented by the said general formula [I], when said R<^1> , R<^2> , R<^4> , R<^5> is a sec-butyl group, and said R<^3> , R<^6> is an ethyl group (ie, copper amidinate) to be.

As for a compound preferable as a compound represented by the said general formula [I], said R ¹ , R ² , R ⁴ , R ⁵ is a sec-butyl group, said R ³ , R ⁶ is an n-butyl group (that is, copper amidinate) ) is the case.

A compound preferable as a compound represented by the general formula [I] is that R ¹ , R ² , R ⁴ , R ⁵ is a phenyl group, R ³ , R ⁶ is a methyl group (ie, copper amidinate) is the case

A preferable compound as a compound represented by the said general formula [I] is a case where said R<^1> , R<^2> , R<^4> , R<^5> is a phenyl group, and said R<^3> , R<^6> is an ethyl group (namely, amidinate copper).

Hereinafter, a more specific example is given. However, the present invention is not limited only to the following examples. As long as the characteristics of the present invention are not significantly impaired, various modifications and application examples are also included in the present invention.

[Example 1: Deposition of copper in _{CO 2} supercritical fluid using (N,N'-diisopropylpropionamidinate) copper complex]

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram of a SCD device in which a method for forming a copper-based film of the present invention is implemented.

1, 1 is a CO ₂ high-pressure cylinder, 2 is a H ₂ high-pressure cylinder, 3 is a cooling device, 4 is a pressure pump (10MP), 5 is a mixer (混合器) ), 6 is the vessel, 7 is the heater, 8 is the preheating chamber, 9 is the reaction chamber, 10 is the substrate (ruthenium thin film) ) formed on a silicon substrate), and reference numeral 11 denotes a back pressure control device.

A solution of (N,N'-diisopropylpropionamidinate) in acetone (concentration of 3.34×10 ⁻⁵ mol) of copper diomer is placed in a container (6).

The reaction chamber 9 is maintained at 140° C. by a heater 7 . _{Supercritical fluid (CO 2} ) in the reaction chamber 9 + H ₂ ) is maintained at 13 MP. CO ₂ The partial pressure was 12 MPA, and the H ₂ partial pressure was 1 MPA.

An acetone solution of (N,N'-diisopropylpropionamidinate) copper diisomer was supplied into the reaction chamber 9 by a pump 4 . That is, (N,N'-diisopropylpropionamidinate)copper diamide was supplied in the supercritical fluid. As a result, a copper film was deposited. The substrate 10 was taken out 15 minutes after the start of the raw material supply. A copper-colored film was formed on the taken out substrate 10 .

The substrate 10 was subjected to ESD analysis (Energy dispersive X-ray spectrometry). According to this, C and O were not recognized in the film on the surface of the substrate 10 . X-ray diffraction revealed that the film was mainly a (111) oriented copper thin film. According to an electron microscope, it was found that the inside of the groove (width 140 nm, depth 1.6 μm) formed in the substrate 10 was completely filled with copper (refer to Fig. 2).

[Example 2]

The same procedure was carried out in Example 1 except that the heating temperature by the heater 7 was changed from 140°C to 160°C. As a result, it was the same result as Example 1 (refer FIG. 3). In general, when the temperature is high, the fillability is inferior. However, the higher the temperature, the better the throughput. This example shows that good filling properties were obtained at 160°C.

[Example 3]

In Example 1, the same procedure was performed except that n-pentane was used instead of acetone. As a result, it was the same result as Example 1. However, the solubility is lower than in the case of acetone, the concentration of the raw material solution is low, and the deposition time is about 20% longer.

[Example 4]

In Example 1, the same procedure was performed except that cyclohexane was used instead of acetone. As a result, it was the same result as Example 1. However, the solubility is lower than in the case of acetone, the concentration of the raw material solution is low, and the deposition time is about 20% longer.

[Example 5]

In Example 1, the same procedure was performed except that n-heptane was used instead of acetone. As a result, it was the same result as Example 1. However, the solubility is lower than in the case of acetone, the concentration of the raw material solution is low, and the deposition time is about 20% longer.

[Example 6]

In Example 1, the same procedure was performed except that n-octane was used instead of acetone. As a result, the result was the same as in Example 1. However, the solubility is lower than in the case of acetone, the concentration of the raw material solution is low, and the deposition time is about 25% longer.

[Example 7]

In Example 1, the same procedure was performed except that n-nonane was used instead of acetone. As a result, it was the same result as Example 1. However, the solubility is lower than in the case of acetone, the concentration of the raw material solution is low, and the deposition time is about 20% longer.

[Example 8]

In Example 1, the same procedure was performed except that n-decane was used instead of acetone. As a result, it was the same result as Example 1. However, the solubility is lower than in the case of acetone, the concentration of the raw material solution is low, and the deposition time is about 20% longer.

[Example 9]

The same procedure was carried out in Example 1 except that methyl isobutyl ketone was used instead of acetone. As a result, it was the same result as Example 1.

[Example 10]

In Example 1, the same procedure was performed except that diethyl ether was used instead of acetone. As a result, it was the same result as Example 1. However, in the ESD analysis, weakly O was observed in the C-based film.

[Example 11]

In Example 1, the same procedure was performed except that tetrahydrofuran was used instead of acetone. As a result, it was the same result as Example 1. However, in the ESD analysis, weakly O was observed in the C-based film.

[Example 12]

Example 1 was carried out in the same manner except that dioxane was used instead of acetone. As a result, it was the same result as Example 1. However, in the ESD analysis, weakly O was observed in the C-based film.

[Example 13]

In Example 1, the same procedure was carried out except that (N,N'-diisopropylacetamidinate) copper dimer was used instead of (N,N'-diisopropylpropionamidinate) copper dimer. . The obtained film had the same result as in Example 1. However, in order to obtain the same film thickness as in Example 1, about 20% longer time was required.

[Example 14]

The compound of Formula [I] wherein R ¹ , R ² , R ⁴ , R ⁵ is an iso-propyl group and R ³ , R ⁶ is an n-butyl group was used in the same manner as in Example 1. The obtained film had the same result as in Example 1. However, in order to obtain the same film thickness as in Example 1, about 20% longer time was required.

[Example 15]

The compound of Formula [I] wherein R ¹ , R ² , R ⁴ , R ⁵ is an n-propyl group and R ³ , R ⁶ is a methyl group was used, and the same procedure as in Example 1 was used. The obtained film had the same result as in Example 1. However, in order to obtain the same film thickness as in Example 1, about 20% longer time was required.

[Example 16]

The compound of the general formula [I] wherein R ¹ , R ² , R ⁴ , R ⁵ is an n-propyl group and R ³ , R ⁶ is an ethyl group was used in the same manner as in Example 1. The obtained film had the same result as in Example 1. However, in order to obtain the same film thickness as in Example 1, about 20% longer time was required.

[Example 17]

The compound of Formula [I] wherein R ¹ , R ² , R ⁴ , R ⁵ is an n-propyl group and R ³ , R ⁶ is an n-butyl group was used, and the same procedure as in Example 1 was used. The obtained film had the same result as in Example 1. However, in order to obtain the same film thickness as in Example 1, about 20% longer time was required.

[Example 18]

Example 1 was carried out in the same manner as in Example 1 using a compound of Formula [I] wherein R ¹ , R ² , R ⁴ , R ⁵ is an n-butyl group, and R ³ , R ^{6 is a methyl group.} The obtained film had the same result as in Example 1. However, in order to obtain the same film thickness as in Example 1, about 20% longer time was required.

[Example 19]

The compound of Formula [I] wherein R ¹ , R ² , R ⁴ , R ⁵ is an n-butyl group and R ³ , R ⁶ is an ethyl group was used, and the same procedure as in Example 1 was used. The obtained film had the same result as in Example 1. However, in order to obtain the same film thickness as in Example 1, about 20% longer time was required.

[Example 20]

The compound of Formula [I] wherein R ¹ , R ² , R ⁴ , R ⁵ is an iso-butyl group and R ³ , R ⁶ is a methyl group was used, and the same procedure as in Example 1 was used. The obtained film had the same result as in Example 1. However, in order to obtain the same film thickness as in Example 1, about 20% longer time was required.

[Example 21]

The compound of the general formula [I] wherein R ¹ , R ² , R ⁴ , R ⁵ is an iso-butyl group and R ³ , R ⁶ is an ethyl group was used in the same manner as in Example 1. The obtained film had the same result as in Example 1. However, in order to obtain the same film thickness as in Example 1, about 20% longer time was required.

[Example 22]

The compound of Formula [I] wherein R ¹ , R ² , R ⁴ , R ⁵ is an iso-butyl group and R ³ , R ⁶ is an n-butyl group was used, and the same procedure as in Example 1 was used. The obtained film had the same result as in Example 1. However, in order to obtain the same film thickness as in Example 1, about 20% longer time was required.

[Example 23]

The compound of Formula [I] wherein R ¹ , R ² , R ⁴ , R ⁵ is a sec-butyl group and R ³ , R ⁶ is a methyl group was used in the same manner as in Example 1. The obtained film had the same result as in Example 1. However, in order to obtain the same film thickness as in Example 1, about 20% longer time was required.

[Example 24]

The compound of Formula [I] wherein R ¹ , R ² , R ⁴ , R ⁵ is a sec-butyl group and R ³ , R ⁶ is an ethyl group was used, and the same procedure as in Example 1 was used. The obtained film had the same result as in Example 1. However, in order to obtain the same film thickness as in Example 1, about 20% longer time was required.

[Example 25]

The compound of Formula [I] wherein R ¹ , R ² , R ⁴ , R ⁵ is a sec-butyl group and R ³ , R ⁶ is an n-butyl group was used, and the same procedure as in Example 1 was used. The obtained film had the same result as in Example 1. However, in order to obtain the same film thickness as in Example 1, about 20% longer time was required.

[Example 26]

Example 1 was carried out in the same manner as in Example 1 using a compound of Formula [I] wherein R ¹ , R ² , R ⁴ , R ⁵ is a phenyl group and R ³ , R ^{6 is a methyl group.} The obtained film had the same result as in Example 1. However, in order to obtain the same film thickness as in Example 1, about 30% longer time was required.

[Example 27]

Example 1 was carried out in the same manner as in Example 1 using the compound of Formula [I], wherein R ¹ , R ² , R ⁴ , R ⁵ is a phenyl group, and R ³ , R ^{6 is an ethyl group.} The obtained film had the same result as in Example 1. However, in order to obtain the same film thickness as in Example 1, about 25% longer time was required.

[Comparative Example 1]

The same procedure as in Example 1 was carried out using _{bisdiisobutylmethanatocopper [Cf(cnm) 2} ] instead of the compound of the general formula [I] in Example 1. However, the C film was not formed.

[Comparative Example 2]

In Comparative Example 1, the same procedure was performed except that the heating temperature by the heater 7 was changed from 140°C to 240°C. In this comparative example, a C film was formed. However, impurities C and O were detected in the C film.

[Comparative Example 3]

Example 1 was carried out in the same manner as in Example 1 by using bishexafluoroacetylacetonatocopper [Cf(ab)2] in place of the compound of the general formula [I] in Example 1. However, the C film was not formed.

[Comparative Example 4]

In Comparative Example 3, the same procedure was performed except that the heating temperature by the heater 7 was changed from 140°C to 240°C. In this comparative example, a C film was formed. However, impurities C, O, and F were detected in this C film.

1: CO ₂ high pressure cylinder
2: H ₂ high pressure cylinder
3: Chiller
4: pressure pump
5: mixer
6: Raw material container
7: Burner
8: pre-heating room
9: reaction room
10: substrate
11: Back pressure control device

Claims (11)

A method of forming a copper-based film on a gas in a supercritical fluid, comprising:
Forming a copper-based film by dissolving a compound represented by the following general formula [I] in a supercritical fluid of CO _{2 and depositing copper in a gas phase}
A method of forming a copper-based film.
general formula [I]

[R ¹ , R ² , R ³ , R ⁴ , R ⁵ , and R ⁶ are hydrocarbon groups having 1 to 10 carbon atoms. R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ may all be the same or different.]
According to claim 1,
that the compound represented by the general formula [I] dissolved in a solvent is supplied into the supercritical fluid, so that the compound is dissolved in the supercritical fluid
A method of forming a copper-based film.
3. The method of claim 1 or 2,
R ¹ , R ² , R ⁴ , R ⁵ is an iso-propyl group, R ³ , R ⁶ is a methyl group, an ethyl group, an n-butyl group ) that is any one selected from the group of
A method of forming a copper-based film.
3. The method of claim 1 or 2,
R ¹ , R ² , R ⁴ , R ⁵ is an n-propyl group (n-propyl group), R ³ , R ⁶ is any one selected from the group consisting of a methyl group, an ethyl group, and an n-butyl group
A method of forming a copper-based film.
3. The method of claim 1 or 2,
R ¹ , R ² , R ⁴ , R ⁵ is an n-butyl group, R ³ , R ⁶ is any one selected from the group consisting of a methyl group and an ethyl group
A method of forming a copper-based film.
3. The method of claim 1 or 2,
R ¹ , R ² , R ⁴ , R ⁵ is an iso-butyl group, R ³ , R ⁶ is any one selected from the group consisting of a methyl group, an ethyl group, and an n-butyl group
A method of forming a copper-based film.
3. The method of claim 1 or 2,
R ¹ , R ² , R ⁴ , R ⁵ is a sec-butyl group, R ³ , R ⁶ is any one selected from the group consisting of a methyl group, an ethyl group, and an n-butyl group
A method of forming a copper-based film.
3. The method of claim 1 or 2,
R ¹ , R ² , R ⁴ , R ⁵ is a phenyl group, R ³ , R ⁶ is any one selected from the group consisting of a methyl group and an ethyl group
A method of forming a copper-based film.
3. The method of claim 2,
The solvent is pentane, hexane, heptane, octane, nonane, decane, acetone, methyl isobutyl ketone, diethyl ether (diethylether), tetrahydrofuran (tetrahydrofuran) and dioxane (dioxane) one or two or more selected from the group
A method of forming a copper-based film.
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