JPH09235287A - Metal complex and formation of metal thin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a new metal complex consisting of a specific (cyclopentadlenyl) (dimethylcyclooctadiene) complex, large in a film-forming speed, hardly leaving evaporation resides, and useful as a vacuum deposition raw material for forming metal thin films for semiconductor devices, etc. SOLUTION: A new metal complex represented by formula I (R is a 1-4C alkyl, H; M is Cu, Ag, Co, Ru, Rh, Pt) or formula II. The metal complex is large in a film-forming speed, hardly leaves evaporation residues, is low in a final evaporation temperature, and is useful as a vacuum deposition raw material capable of easily and efficiently forming various kinds of thin metal films used as wiring materials for semiconductor devices, etc. The new metal complex is obtained by putting deaerated anhydrous tetrahydrofuran and a metal hallde (e.g. copper chloride) into a dry reactor purged with nitrogen gas, dropwisely adding dimethylcyclooctadiene, etc., cooled to 0 deg.C into the reactor, vigorously stirring the mixture for a night, dropwisely adding cyclopentadienyl sodium, etc., at -30 deg.C to the reaction solution, returning the reaction solution to room temperature, stirring at the room temperature for 30min, hydrolyzlng the reaction product and subsequently extracting the metal complex.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel metal complex and a method for forming a metal thin film by vapor deposition using the same.

[0002]

2. Description of the Related Art Conventionally, various organic silver compounds have been provided as vapor deposition raw materials used when forming various silver thin films such as contacts and wirings of semiconductor devices by MOCVD.

For example, in Japanese Patent Application No. 7-114578,
A silver complex represented by the following structural formula has been proposed as being superior in thermal stability and volatility to conventional organic silver compounds.

[0004]

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To form a silver thin film by the MOCVD method using such a vapor deposition material, for example, as shown in the schematic explanatory view of FIG. 1, the substrate 5 is placed on a heater 6 provided in a reaction furnace 7, On the other hand, in the heating furnace 3 provided so as to be connected to the reaction furnace 7, the vapor deposition material 1 made of the above silver complex in the vaporization container 2
Vaporized, and the resulting vapor is introduced through the pipe 4 as Ar.
A carrier gas such as the above is fed into the reaction furnace 7 to be diffused, and silver is deposited on the heating substrate 5. In the drawing, reference numeral 8 denotes a vacuum pipe. This method is called a thermal decomposition type MOCVD method.

[0006]

The film deposition rate is high as a required characteristic of the vapor deposition material for the thermal decomposition type MOCVD method. It is difficult for vaporized residue to remain. Evaporation end temperature is low. And the like, and further improvement of these characteristics is desired.

The present invention has been made in view of the above conventional circumstances, and it is a metal complex having a high film formation rate, hardly leaving a vaporization residue, and a low evaporation end temperature, and a metal using such a metal complex. An object is to provide a thin film forming method.

[0008]

MEANS FOR SOLVING THE PROBLEMS The metal complex of the present invention is represented by the following general formula or.

[0009]

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The metal thin film forming method of the present invention uses the above metal complex of the present invention and decomposes the metal complex to deposit a metal thin film on a substrate placed in a reaction furnace.

In the method for forming a metal thin film of the present invention, the raw material is supplied into the reaction furnace by directly vaporizing the metal complex and introducing it together with a carrier gas, or by vaporizing a solution of the metal complex in an organic solvent. And a method of introducing the carrier gas together with the carrier gas. The organic solvent may be aliphatic hydrocarbon, triethylenetetramine, tetraethylenepentamine, ethylenediamine,
An amine organic solvent such as diethylenetriamine can be used.

Further, the decomposition of the metal complex in the reaction furnace is preferably performed not only by thermal decomposition but also by photoexcited decomposition under light irradiation because a highly pure and highly efficient film can be formed at a lower temperature. The decomposition temperature is preferably 200 ° C or lower.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

The metal complex of the present invention is a (cyclopentadienyl) (dimethylcyclooctadiene) complex represented by the above general formula. As shown in Example 1 below, this metal complex is obtained by using a metal halide forming a complex, dimethylcyclooctadiene, cyclopentadienyl (or alkylcyclopentadienyl) sodium having 1 to 4 carbon atoms, or the like. It can be synthesized by reacting with a cyclopentadienyl metal compound in a solvent.

Dimethylcyclooctadiene contains
There are two isomers, 1,5-dimethylcyclooctadiene and 1,6-dimethylcyclooctadiene, depending on the position of the methyl group. When 1,5-dimethylcyclooctadiene is used, the complex of the above general formula is obtained,
When 6-dimethylcyclooctadiene is used, the complex of the above general formula is obtained.

In the present invention, 1,5-dimethylcyclooctadiene may be used alone to synthesize the complex of the above general formula, and 1,6-dimethylcyclooctadiene may be used alone. You may synthesize | combine and use the complex of the said general formula. Further, a mixture of these 1,5-dimethylcyclooctadiene and 1,6-dimethylcyclooctadiene is used to synthesize an isomer mixture of the complex of the general formula and the complex of the general formula to obtain the compound of the present invention. It may be used for forming a metal thin film. In this case, the isomer mixing ratio of the complex is not particularly limited and can be set to any ratio.

The method for forming a metal thin film of the present invention uses such a metal complex and operates in the same manner as in the prior art to produce a thermal decomposition type MOC.
The metal thin film can be formed by the MOCVD method such as the VD method, and the metal thin film can be formed more advantageously by the photoexcitation decomposition MOCVD method.

In the metal thin film forming method according to the present invention,
The raw material, that is, the supply of the metal complex into the reaction furnace, is a method of directly vaporizing the metal complex and introducing it together with a carrier gas,
Alternatively, it can be carried out by a method of vaporizing a solution in which the metal complex is dissolved in an organic solvent and introducing the solution together with a carrier gas. As the organic solvent, an aliphatic hydrocarbon having 5 to 7 carbon atoms such as hexane and heptane, or an amine-based organic solvent such as triethylenetetramine, tetraethylenepentamine, ethylenediamine and diethylenetriamine can be used. It is preferable that the complex is dissolved so that the concentration thereof is about 70 to 80% by weight.

The decomposition of the metal complex in the reaction furnace is more preferably photoexcited decomposition.
It is preferable to perform photoexcitation decomposition by irradiating with light of about 200 mJ / cm ² , 20 Hz.

The decomposition temperature of the metal complex, that is, the substrate temperature in the reaction furnace is preferably 200 ° C. or lower, particularly 100 to 150 ° C. from the viewpoint of film forming efficiency.

[0021]

The present invention will be described more specifically below with reference to examples and comparative examples.

Example 1 Synthesis of Metal Complex The metal complex of the present invention was produced by the following method.

As the metal halide, copper (I) chloride: 8.0 g, silver chloride: 5.0 g, cobalt chloride:
10.2 g, ruthenium chloride: 5.0 g, rhodium chloride: 5.0 g, or platinum chloride: 5.0 g was used.

As dimethylcyclooctadiene, commercially available 1,5-dimethylcyclooctadiene and 1,5-dimethylcyclooctadiene
A mixture with 6-dimethylcyclooctadiene was used.
The mixing ratio of this isomer mixture is 70% 1,5-dimethylcyclooctadiene and 30% 1,6-dimethylcyclooctadiene.

(Synthesis Example 1) 500 ml of anhydrous tetrahydrofuran degassed with nitrogen gas and a metal halide were placed in a three-necked flask which had been dried and purged with nitrogen, and cooled to 0 ° C. Dimethylcyclooctadiene (DMCOD) was added dropwise to the metal halide in an equal amount from a dropping funnel, and the mixture was vigorously stirred overnight. Then, at -30 ° C, an equivalent amount of cyclopentadienyl sodium was added dropwise to the metal halide over 20 minutes, then returned to room temperature and stirred for 30 minutes. Then, the same amount of saturated ammonium chloride aqueous solution as the solvent was added for hydrolysis. The reaction solution was separated into two layers. The upper organic layer was extracted with hexane, while the lower aqueous layer was extracted twice with 100 ml of hexane and combined with the previous organic layer. After drying the extract over anhydrous sodium sulfate, 5
After concentration under reduced pressure at 0 ° C., the residual oily substance is purified by recrystallization to give (cyclopentadienyl) (dimethylcyclooctadiene) M represented by the following (Chemical Formula 4) in the state shown in Table 1 at room temperature. (Hereinafter, "CpMDMCOD" (M = C
u, Ag, Co, Ru, Rh, Pt). ) A mixture of isomers was obtained (melting points shown in Table 1).

[0026]

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(Synthesis Example 2) The same procedure as in Synthesis Example 1 was repeated except that monomethylcyclopentadienyl sodium was used instead of cyclopentadienyl sodium.
(Monomethylcyclopentadienyl) (dimethylcyclooctadiene) M represented by the following (Chemical Formula 5) in the state shown in
(Hereinafter “MeCpMDMCOD” (M = Cu, Ag, C
o, Ru, Rh, Pt). ) A mixture of isomers was obtained (melting points shown in Table 2).

[0028]

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(Synthesis Example 3) The same procedure as in Synthesis Example 1 was repeated except that monoethylcyclopentadienyl sodium was used in place of cyclopentadienyl sodium.
(Monoethylcyclopentadienyl) (dimethylcyclooctadiene) M represented by the following (Chemical Formula 6) in the state shown in
(Hereinafter “EtCpMDMCOD” (M = Cu, Ag, C
o, Ru, Rh, Pt). ) A mixture of isomers was obtained (melting points shown in Table 3).

[0030]

[Chemical 6]

(Synthesis Example 4) In the same manner as in Synthesis Example 1, except that monopropylcyclopentadienyl sodium was used in place of cyclopentadienyl sodium, the following (Chemical Formula 7) in the state shown in Table 4 at room temperature was used. Represented (monopropylcyclopentadienyl) (dimethylcyclooctadiene) M (hereinafter "PrCpMDMCOD" (M = Cu, A
g, Co, Ru, Rh, Pt). ) A mixture of isomers was obtained (melting points shown in Table 4).

[0032]

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(Synthesis Example 5) Table 5 at room temperature in the same manner as in Synthesis Example 1 except that monobutylcyclopentadienyl sodium was used in place of cyclopentadienyl sodium.
(Monobutylcyclopentadienyl) (dimethylcyclooctadiene) M represented by the following (Chemical Formula 8) in the state shown in
(Hereinafter “BuCpMDMCOD” (M = Cu, Ag, C
o, Ru, Rh, Pt). ) A mixture of isomers was obtained (melting points shown in Table 5).

[0034]

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The metal complexes obtained in Synthesis Examples 1 to 5 were identified by main elemental analysis and C, H simultaneous elemental analysis, and the results are shown in Tables 1 to 5, respectively.

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

[Table 3]

[0039]

[Table 4]

[0040]

[Table 5]

For comparison purposes, conventional Cu, Ag, C
The following compounds, which are known as vapor deposition materials for the thermal decomposition MOCVD method of o, Ru, Rh, and Pt, were synthesized and used for comparative tests.

Cu complex: The following [Chemical formula 9] (where M = C
u) Copper complex represented by (comparative metal complex I) Ag complex: [Chemical formula 9] below (wherein M = Ag) (complex metal complex II) Co complex represented by: [Chemical formula 10] However, a cobalt complex represented by M = Co (comparative metal complex III) Ru complex: [Chemical Formula 10] (where M = Ru) a ruthenium complex (comparative metal complex IV) Rh complex: Chemical formula 11] (where M = Rh) Rhodium complex (comparative metal complex V) Pt complex: Chemical formula 12 below (where M = Pt. 1,5
-Dimethylcyclooctadiene and 1,6-dimethylcyclooctadiene isomer mixing ratio is the same as in Example 1) Platinum complex represented by (Comparative Metal Complex VI)

[0043]

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[0044]

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[0045]

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[0046]

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Example 2: Evaluation of vaporization characteristics Using the metal complex according to the present invention synthesized in Example 1 and comparative metal complexes I to VI, for the purpose of evaluating vaporization characteristics, a thermogravimetric (TG) curve ( The temperature rate of 10 ° C./min, nitrogen atmosphere) is shown in FIGS.

2 to 7, I to VI represent comparative metal complexes I to VI, H represents CpMDMCOD,
Me is MeCpMDMCOD, Et is EtCpMDM
COD, Pr for PrCpMDMCOD, Bu for Bu
CpMDMCOD is shown.

2 to 6, each of the metal complexes of the present invention can be completely vaporized at a lower temperature than the comparative metal complexes I to VI, the vaporization end temperature is low, and the residue hardly remains. I understand.

Example 3 Formation of Metal Thin Film Using the metal complex according to the present invention synthesized in Example 1 and comparative metal complexes I to VI, pyrolysis CV was carried out by the apparatus shown in FIG.
A metal thin film was formed by the method D under the following conditions, and the film thickness was measured every 10 minutes. The results are shown in Tables 6 to 11. In addition,
The film thickness was measured from a cross-sectional SEM image of the film.

In Tables 6 to 11, the residual amount of TG vaporization and the vaporization starting temperature in Example 2 are shown together.

Substrate: TiN on a 25 mm square Si substrate
((Cyclopentadienyl) (dimethylcyclooctadiene) complex and the copper complex of the prior application 1) or Ti (other cases) substrate deposited by sputtering to a thickness of 100 nm Substrate temperature: 250 ° C (however , CpPtDMCOD, M
eCpPtDMCOD, 200 for conventional metal complex VI
° C) Vaporization temperature; pressure shown in each table; 2 torr carrier gas flow rate; 100 ccm of H ₂

[0053]

[Table 6]

[0054]

[Table 7]

[0055]

[Table 8]

[0056]

[Table 9]

[0057]

[Table 10]

[0058]

[Table 11]

It can be seen from Tables 6 to 11 that all the metal complexes of the present invention have a higher film formation rate than the comparative metal complex.

Example 4: Formation of metal thin film A thin film was formed by using the metal complex of the present invention shown in Table 12, and a thin film of 50 μm was formed under the best conditions. The utilization rate of film formation was evaluated according to the following criteria, and the results are shown in Table 12.

Supply quantitative property index: Liquefied and recovered by placing a cooling trap in the reactor part, and the recovered weight% was calculated with the weight of the complex vaporized for a certain period of time as 100.
The comparison was made with an index of 00.

Utilization index: The deposition weight% of the thin film on the substrate was determined with the weight of the metal in the vaporized complex being 100, and this value was compared with the conventional example as an index.

When the metal complex was dissolved in the solvent, it was dissolved so that the concentration of the metal complex was 70 to 80% by weight. Excimer laser (XeCl) 3 is used for light irradiation.
Light of 08 nm was used.

From Table 12, the following is clear. That is, the metal complex may be directly vaporized or may be dissolved by using a solvent to be vaporized, but in any case, it is preferably photoexcited and decomposed by irradiation with light. When dissolved in a solvent, an aliphatic hydrocarbon such as hexane or heptane or an amine can be used as the solvent. Further, the decomposition concentration is preferably 200 ° C. or lower.

[0065]

[Table 12]

[0066]

As described in detail above, the metal complex of the present invention has a high film-forming rate, is less likely to leave a vaporization residue, and has a low evaporation end temperature. According to the method for forming a metal thin film, various metal thin films useful as wiring materials for semiconductor devices can be easily and efficiently formed.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an apparatus for explaining a thermal decomposition type MOCVD method.

FIG. 2 is a graph showing a thermogravimetric curve of a copper complex.

FIG. 3 is a graph showing a thermogravimetric curve of a silver complex.

FIG. 4 is a graph showing a thermogravimetric curve of a cobalt complex.

FIG. 5 is a graph showing a thermogravimetric curve of a ruthenium complex.

FIG. 6 is a graph showing a thermogravimetric curve of a rhodium complex.

FIG. 7 is a graph showing a thermogravimetric curve of a platinum complex.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Deposition raw material 2 Vaporization container 3 Heating furnace 4 Carrier gas introduction piping 5 Substrate 6 Heater 7 Reactor 8 Vacuum piping

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Claims (9)

[Claims] 1. A metal complex represented by the following general formula or: Embedded image 2. A metal thin film forming method comprising depositing a metal thin film on a substrate arranged in a reaction furnace by decomposing a metal complex for forming a metal thin film, wherein the metal complex is the metal complex according to claim 1. And a method of forming a metal thin film. 3. The method according to claim 2, wherein the supply of the raw material into the reaction furnace directly vaporizes the metal complex for forming a metal thin film,
A method for forming a metal thin film, which is a method of introducing the metal thin film together with a carrier gas. 4. The method according to claim 2, wherein the raw material is supplied into the reaction furnace by vaporizing a solution of a metal complex for forming a metal thin film in an organic solvent and introducing the solution together with a carrier gas. Method for forming metal thin film. 5. The method for forming a metal thin film according to claim 2, wherein the decomposition of the metal complex for forming a metal thin film in the reaction furnace is photoexcitation decomposition. 6. The method for forming a metal thin film according to claim 2, wherein a decomposition temperature of the metal complex for forming a metal thin film in a reaction furnace is 200 ° C. or lower. 7. The method of claim 4, wherein the organic solvent that dissolves the metal complex for forming a metal thin film is an aliphatic hydrocarbon. 8. The method for forming a metal thin film according to claim 4, wherein the organic solvent that dissolves the metal complex for forming a metal thin film is an amine solvent. 9. The method according to claim 8, wherein the amine-based organic solvent dissolving the metal complex for forming a metal thin film is one or two selected from the group consisting of triethylenetetramine, tetraethylenepentamine, ethylenediamine and diethylenetriamine. The above is the method for forming a metal thin film.