JP2007051124A - New copper complex and method for producing copper-containing thin film using the same copper complex - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new copper complex and to provide a method for producing a copper-containing thin film at a lower base temperature. <P>SOLUTION: The copper complex is represented by formula (1) äwherein, R<SP>1</SP>and R<SP>2</SP>are each as follows. (1) R<SP>1</SP>is an ethyl group; and R<SP>2</SP>is a methyl group; (2) R<SP>1</SP>is an ethyl group; and R<SP>2</SP>is a hydrogen atom; or (3) R<SP>1</SP>is a t-butyl group; and R<SP>2</SP>is a hydrogen atom}. The method for producing the copper-containing thin film is carried out by a chemical vapor deposition method using the copper complex as a copper supply source. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a novel copper complex excellent in forming a copper thin film containing copper atoms by a chemical vapor deposition method (hereinafter referred to as a CVD method). The present invention also relates to a method for producing a copper-containing thin film using the copper complex.

  In recent years, many researches and developments have been made on metal complex compounds as materials in the fields of semiconductors, electronic components, optical components and the like. For example, since a copper thin film obtained by using a copper complex compound has a small electric resistance, it can be used as a material for electric wiring and wiring for a silicon semiconductor, and therefore, many researches and developments have been made. A copper oxide thin film containing copper oxide as a constituent component has attracted attention as a material for a high-temperature superconductor. As a method for producing a copper thin film or copper oxide thin film containing these metal atoms, film formation by a CVD method, which is easy to produce a uniform thin film, has been most actively employed, and a raw material compound suitable for it has been demanded. .

  By the way, as a raw material for producing a copper thin film containing copper atoms by the CVD method, for example, a copper complex having β-diketonate as a ligand is being widely used. This copper complex having β-diketonato as a ligand is excellent in stability and sublimation, and is useful as a copper source in the CVD method. As specific examples of the β-diketonato ligand, for example, acetylacetonate (acac) and 2,2,6,6-tetramethyl-3,5-heptanedionate (dpm) are generally known. .

  However, since most of the copper complexes having β-diketonato as a ligand are solid at room temperature and have a high melting point, the piping in the material supply system in the CVD apparatus is blocked during film formation by the CVD method. Therefore, it is not suitable as a raw material for producing a thin film by an industrial CVD method.

  Therefore, attempts have been actively made to stabilize the copper complex, lower the melting point, and improve the productivity of the copper thin film. Among these, studies have been made to stabilize copper complexes, lower melting points, and improve productivity of copper thin films by introducing various substituents with β-diketonato as a ligand.

  For example, for a copper complex having a copper atom as a central metal, the formula (2)

The manufacturing result of the copper containing thin film using the copper complex (bis (2,6-dimethyl-2-trimethylsilyloxy-3,5-heptanedionato) copper (II)) shown by these is disclosed (for example, patent document 1) reference). However, in the production of the copper-containing thin film using the copper complex of the formula (2), there is a problem that the copper-containing thin film is not formed unless the substrate temperature is still high (for example, Example 1 and Reference Example 1) comparison). Note that bis (2-methyl-2-trimethylsilyloxy-3,5-heptanedionato) copper (II) of the present invention was not described at all.

JP 2003-292495 A

  An object of the present invention is to solve the above problems and provide a method for producing a copper-containing thin film using a copper complex or a solvent solution of a copper complex at a lower base temperature.

  The subject of this invention is general formula (1).

（式中、Ｒ^１及びＲ^２は、(1)Ｒ^１＝エチル基、Ｒ^２＝メチル基、(2)Ｒ^１＝エチル基、Ｒ^２＝水素原子、(3)Ｒ^１＝t-ブチル基、Ｒ^２＝水素原子、のいずれかを示す。）
で示される新規な銅錯体(II)によって解決される。

(In the formula, R ¹ and R ² are (1) R ¹ = ethyl group, R ² = methyl group, (2) R ¹ = ethyl group, R ² = hydrogen atom, (3) R ¹ = t-butyl. Group, R ² = hydrogen atom.)
It is solved by a novel copper complex (II) represented by

  The object of the present invention is also solved by a method for producing a copper-containing thin film, characterized by using the copper complex.

  According to the present invention, a method for producing a copper-containing thin film using a novel copper complex or a solvent solution of a copper complex by chemical vapor deposition (CVD) can be provided.

  The β-diketone which is the base of β-diketonato which is a ligand of the copper complex of the present invention is a compound which can be easily synthesized by a known method (described in Reference Examples described later).

  In the CVD method, it is necessary to vaporize the copper complex in order to form a copper thin film. As a method for vaporizing the copper complex of the present invention, for example, the vaporization is performed by filling or transporting the copper complex itself into the vaporization chamber. In addition to the method of making the copper complex, an appropriate solvent (for example, aliphatic hydrocarbons such as hexane, octane, methylcyclohexane and ethylcyclohexane; aromatic hydrocarbons such as toluene; ethers such as tetrahydrofuran and dibutyl ether) A method (solution method) in which a solution diluted in (a solvent solution of a copper complex) is introduced into a vaporization chamber with a liquid transfer pump and vaporized can be used.

  As a method for depositing copper on a substrate, it can be performed by a known CVD method. For example, copper oxidation is performed on a substrate heated with an oxidizing gas such as oxygen under normal pressure or reduced pressure to oxidize copper. A method for depositing a film, a method for depositing a copper nitride film by feeding a copper complex onto a substrate heated with a nitrogen-containing basic gas such as ammonia gas, a copper complex on a substrate heated with a reducing gas such as hydrogen A method of sending a complex and depositing a copper film can be used. Moreover, the method of vapor-depositing a copper containing thin film by plasma CVD method can also be used.

  When depositing a copper-containing thin film using the copper complex of the present invention, as the deposition conditions, for example, the pressure in the reaction system is preferably 1 Pa to 200 kPa, more preferably 10 Pa to 110 kPa, and the substrate temperature is preferably 50. -300 degreeC, More preferably, it is 100-270 degreeC, The temperature which vaporizes a copper complex becomes like this. Preferably it is 50-270 degreeC, More preferably, it is 90-250 degreeC.

  The content ratio of the oxidizing gas with respect to the total gas amount when the copper oxide film is deposited by an oxidizing gas such as oxygen is preferably 10 to 90% by volume, more preferably 20 to 70% by volume. On the other hand, the content ratio of the reducing gas with respect to the total gas amount when the copper thin film is deposited by a reducing gas such as hydrogen is preferably 10 to 95% by volume, more preferably 30 to 90% by volume. Further, the content ratio of the nitrogen-containing basic gas to the total gas amount when the copper thin film is deposited by the nitrogen-containing basic gas such as ammonia gas is preferably 10 to 95% by volume, more preferably 20 to 90% by volume. It is.

  Next, the present invention will be specifically described with reference to examples, but the scope of the present invention is not limited thereto.

Reference Example 1 (Synthesis of methyl 2-trimethylsilyloxyisobutyrate)
After replacing the inside of the reaction system with argon in a 1 L flask equipped with a stirrer, thermometer and dropping funnel, methyl 2-hydroxyisobutyrate 54.0 g (457 mmol), tri n-butylamine 86.0 g (464 mmol) and 300 ml of methylcyclohexane was added. Next, 49.5 g (456 mmol) of chlorotrimethylsilane was slowly added dropwise while maintaining the liquid temperature at 15 ° C., and the mixture was reacted at the same temperature for 1 hour with stirring. After completion of the reaction, 120 ml of water was added to the reaction solution under ice cooling. The organic layer was separated, washed with water, and dried over anhydrous sodium sulfate. After filtration, the filtrate was concentrated, and the concentrate was distilled under reduced pressure (74 ° C., 5.32 kPa) to obtain 61.0 g of methyl 2-trimethylsilyloxyisobutyrate as a colorless liquid (isolated yield: 70%).
The physical properties of methyl 2-trimethylsilyloxyisobutyrate were as follows.

¹ H-NMR (CDCl ₃ , δ (ppm)); 0.08 (9H, s), 1.40 (6H, s), 3.67 (3H, s)
MS (m / e); 175, 131, 99, 73

Reference Example 2 (Synthesis of 2-methyl-2-trimethylsilyloxy-3,5-heptanedione (hereinafter referred to as H-SOED))
After replacing the inside of the reaction system with argon in a flask having an internal volume of 200 ml equipped with a stirrer, a thermometer and a dropping funnel, 11.2 g (99.8 mmol) of potassium t-butoxide and 40 ml of tetrahydrofuran were added. Next, under water cooling, 7.20 g (99.8 mmol) of 2-butanone was slowly added dropwise and stirred for 10 minutes, and then 9.70 g (51.0 mmol) of methyl 2-trimethylsilyloxyisobutyrate synthesized in the same manner as in Reference Example 1 was added. The solution was added dropwise and reacted at 5 ° C. for 1 hour with stirring. After completion of the reaction, 8 g (133 mmol) of acetic acid and 16 ml of water were added under ice cooling. The organic layer was separated, washed with water, and dried over anhydrous sodium sulfate. After filtration, the filtrate was concentrated, and the concentrate was distilled under reduced pressure (118 ° C., 2.66 kPa) to obtain 4.46 g of 2-methyl-2-trimethylsilyloxy-3,5-heptanedione as a colorless liquid (isolation) Yield: 38%).
The physical properties of 2-methyl-2-trimethylsilyloxy-3,5-heptanedione were as follows.

¹ H-NMR (CDCl ₃ , δ (ppm)); 0.12 (2.61 H, s), 0.13 (6.39 H, s), 1.03 (0.87, t), 1.12 (2.13 H, t), 1.32 (1.74 H, s), 1.37 (4.26H, s), 2.32 (0.58H, q), 2.49 (1.42H, q), 3.68 (0.58H, s), 5.94 (0.71H, s), 15.4 (0.71H, s)
IR (neat (cm ^-1 )); 2980, 1607 (br), 1460, 1377, 1359, 1253, 1197, 1114, 1045, 915, 842, 755
(The peak at 1607 cm ^{-1 is} a peak peculiar to β-diketone.)
MS (m / e); 215, 131, 73, 29

Example 1 (copper complex (1); synthesis of bis (2-methyl-2-trimethylsilyloxy-3,5-heptanedionato) copper (II) (hereinafter referred to as Cu (soed) ₂ ))
To a 500-ml flask equipped with a stirrer, thermometer and dropping funnel, 35.63 g (154.7 mmol) of 2-methyl-2-trimethylsilyloxy-3,5-heptanedione synthesized in the same manner as in Reference Example 2 and 100 ml of methylcyclohexane was added, and then a solution of 16.1 g (80.8 mmol) of copper acetate monohydrate dissolved in 240 ml of water was slowly added dropwise and reacted at room temperature for 1 hour with stirring. After completion of the reaction, the organic layer was separated from the reaction solution, the organic layer was concentrated, and the concentrate was distilled under reduced pressure (165 ° C., 27 Pa) to give bis (2-methyl-2-trimethylsilyloxy as a dark green solid. -3,5-Heptanedionato) copper (II) 34.2 g was obtained (isolation yield: 81%).
Bis (2-methyl-2-trimethylsilyloxy-3,5-heptanedionato) copper (II), a novel compound represented by the following physical properties.

Melting point: 53 ° C
IR (neat (cm ^-1 )); 3500 (br), 1567, 1522, 1507, 1431, 1414, 1375, 1249, 1203, 1187, 1147, 1051, 920, 861, 838, 751, 633, 534
(The peak peculiar to β-diketone (1607cm ^-1 ) disappeared and the peak peculiar to β-diketonato (1567cm ^-1 ) was observed.)
Elemental analysis _{(C 22 H 42 O 6 Si} 2 Cu); Carbon: 50.9%, hydrogen: 8.13%, copper: 12.2%
(Theoretical value: Carbon: 50.6%, Hydrogen: 8.11%, Copper: 12.2%)
MS (m / e); 514, 423, 391, 375, 259, 215, 131, 73

Reference Example 3 (Synthesis of methyl 2-trimethylsilyloxy lactate)
After replacing the inside of the reaction system with argon in a flask having an internal volume of 3 L equipped with a stirrer, a thermometer and a dropping funnel, 156.3 g (1.50 mol) of 2-hydroxymethyl lactate, 291.5 g (1.57 mmol) of tri-n-butylamine And 1000 ml of methylcyclohexane were added. Next, 163.5 g (1.51 mol) of chlorotrimethylsilane was slowly dropped while maintaining the liquid temperature at 15 ° C., and the mixture was reacted at the same temperature for 1 hour with stirring. After completion of the reaction, 400 ml of water was added to the reaction solution under ice cooling. The organic layer was separated, washed with water, and dried over anhydrous sodium sulfate. After filtration, the filtrate was concentrated, and the concentrate was distilled under reduced pressure (96 ° C., 11.4 kPa) to obtain 185.7 g of methyl 2-trimethylsilyloxylactate as a colorless liquid (isolated yield: 70%).
The physical properties of methyl 2-trimethylsilyloxylactate were as follows.

¹ H-NMR (CDCl ₃ , δ (ppm)); 0.11 (3H, s), 1.32 (3H, d), 3.80 (3H, s), 4.18 (1H, q)
MS (m / e); 176

Reference Example 4 (Synthesis of 2-trimethylsilyloxy-3,5-heptanedione (hereinafter referred to as H-DSOED))
Under an argon atmosphere, 9.50 g (84.6 mmol) of potassium t-butoxide, 65 ml of methylcyclohexane, and 20 ml of tetrahydrofuran were added to a flask having an internal volume of 300 ml equipped with a stirrer, a thermometer, and a dropping funnel. Subsequently, 6.41 g (89 mmol) of 2-butanone was added dropwise while maintaining the liquid temperature at 10 ° C. After stirring at 10 ° C. for 1 hour, the mixture was cooled to −10 ° C., and 14.5 g (82 mmol) of methyl 2-trimethylsilyloxylactate synthesized in the same manner as in Reference Example 1 was slowly added dropwise at −10 ° C. with stirring. The reaction was allowed for 15 minutes. After completion of the reaction, 5.6 g (93 mmol) of acetic acid and 20 g of water were added under ice cooling. Next, the organic layer was separated, washed with water, and dried over anhydrous sodium sulfate. After filtration, the filtrate was concentrated, and the concentrate was distilled under reduced pressure (100 ° C., 1.51 kPa) to obtain 4.80 g of 2-trimethylsilyloxy-3,5-heptanedione as a colorless liquid (isolated yield) : 27%).
The physical properties of 2-trimethylsilyloxy-3,5-heptanedione were as follows.

¹ H-NMR (CDCl ₃ , δ (ppm)); 0.11 (9H, s), 1.13 (3H, t), 1.32 (3H, d), 2.48 (2H, q), 4.18 (1H, q), 5.84 (1H, s), 15.4 (1H, s)
IR (neat (cm ^-1 )); 2971, 2876, 1607, 1253, 1125, 967, 899, 844, 750
(The peak at 1607 cm ^{-1 is} a peak peculiar to β-diketone.)
MS (m / e); 216

Reference Example 5 (Synthesis of 6,6-dimethyl-2-trimethylsilyloxy-3,5-heptanedione (hereinafter referred to as H-DSOBD))
Under an argon atmosphere, 7.74 g (69 mmol) of potassium t-butoxide, 65 ml of methylcyclohexane, and 20 ml of tetrahydrofuran were added to a flask having an internal volume of 300 ml equipped with a stirrer, a thermometer and a dropping funnel. Subsequently, 7.26 g (72.5 mmol) of pinacholine was added dropwise while maintaining the liquid temperature at 65 ° C. After stirring for 1 hour, cool to -10 ° C, slowly drop 11.8 g (67 mmol) of methyl 2-trimethylsilyloxylactate synthesized in the same manner as in Reference Example 1, and react at -10 ° C for 15 minutes with stirring. I let you. After completion of the reaction, 4.56 g (76 mmol) of acetic acid and 20 g of water were added under ice cooling. Next, the organic layer was separated, washed with water, and dried over anhydrous sodium sulfate. After filtration, the filtrate was concentrated, and the concentrate was distilled under reduced pressure (80 ° C., 266 Pa) to obtain 4.59 g of 6,6-dimethyl-2-trimethylsilyloxy-3,5-heptanedione as a colorless liquid. (Isolated yield: 28%).
The physical properties of 6,6-dimethyl-2-trimethylsilyloxy-3,5-heptanedione were as follows.

¹ H-NMR (CDCl ₃ , δ (ppm)); 0.11 (9H, s), 1.13 (9H, s), 1.32 (3H, d), 4.18 (1H, q), 5.84 (1H, s), 15.4 (1H, s)
IR (neat (cm ^-1 )); 2971, 2876, 1607, 1253, 1125, 967, 899, 844, 750
(The peak at 1607 cm ^{-1 is} a peak peculiar to β-diketone.)
MS (m / e); 244

Example 2 (copper complex (2); synthesis of bis (2-trimethylsilyloxy-3,5-heptanedionato) copper (II) (hereinafter referred to as Cu (dsoed) ₂ ))
To a 50 ml flask equipped with a stirrer, thermometer and dropping funnel was added 5.01 g (23.2 mmol) 2-trimethylsilyloxy-3,5-heptanedione and 10 ml 1,2-dimethoxyethane, followed by hydroxylation 1.14 g (11.7 mmol) of copper was added and reacted at room temperature with stirring for 1 hour. After completion of the reaction, the mixture was filtered to separate the organic layer. After the organic layer was concentrated, the concentrate was distilled under reduced pressure (160 ° C., 29 Pa) to give bis (2-trimethylsilyloxy-3,5 as a purple solid. -Heptanedionato) 5.00 g of copper (II) was obtained (isolation yield: 87%).
Bis (2-trimethylsilyloxy-3,5-heptanedionato) copper (II) is a novel compound represented by the following physical property values.

Melting point: 64 ° C
IR (neat (cm ^-1 )); 3432 (br), 2961, 2879, 1571, 1523, 1461, 1443, 1251, 1127, 1103, 1049, 968, 870, 841, 804, 748
Elemental analysis _{(C 20 H 38 O 6 Si} 2 Cu); Carbon: 48.3%, hydrogen: 7.79%, copper: 12.8%
(Theoretical value: Carbon: 48.6%, Hydrogen: 7.75%, Copper: 12.9%)
MS (m / e); 493, 486, 478, 395, 259, 201, 161, 117, 73

Example 3 (copper complex (3); synthesis of bis (6,6-dimethyl-2-trimethylsilyloxy-3,5-heptanedionato) copper (II) (hereinafter referred to as Cu (dsobd) ₂ ))
To a 50-ml flask equipped with a stirrer, thermometer and dropping funnel, add 5.00 g (20.5 mmol) of 6,6-dimethyl-2-trimethylsilyloxy-3,5-heptanedione and 6 ml of 1,2-dimethoxyethane. Then, 1.12 g (11.5 mmol) of copper hydroxide was added, and the mixture was reacted at room temperature for 1 hour with stirring. After completion of the reaction, the mixture was filtered to separate the organic layer. After the organic layer was concentrated, the concentrate was distilled under reduced pressure (160 ° C., 29 Pa) to give bis (6,6-dimethyl-2- 3.80 g of trimethylsilyloxy-3,5-heptanedionato) copper (II) was obtained (isolation yield: 60%).
Bis (6,6-dimethyl-2-trimethylsilyloxy-3,5-heptanedionato) copper (II) is a novel compound represented by the following physical property values.

Melting point: 72 ° C
IR (neat (cm ^-1 )); 3429 (br), 2974, 2932, 2904, 2868, 1565, 1533, 1506, 1412, 1391, 1364, 1343, 1254, 1204, 1157, 1132, 1101, 1047, 970 , 871, 842, 808, 747, 627, 549, 497, 424
Elemental analysis _{(C 24 H 46 O 6 Si} 2 Cu); Carbon: 52.3%, hydrogen: 8.49%, copper: 11.5%
(Theoretical value: Carbon: 52.4%, Hydrogen: 8.42%, Copper: 11.6%)
MS (m / e); 493, 486, 478, 395, 259, 201, 161, 117, 73

Example 4 (Vapor deposition experiment; Production of copper thin film)
Copper complexes (copper complexes (1) to (3)) obtained in Examples 1 to 3 and copper complexes synthesized by a known method (Cu (sopd) ₂ ; bis (2,6-dimethyl-2-trimethylsilyloxy) -3,5-Heptanedionato) copper (II)) was used to evaluate the film formation characteristics by conducting a vapor deposition experiment by the CVD method.
The apparatus shown in FIG. 1 was used for the evaluation test. The copper complex 20 in the vaporizer 3 (glass ampoule) is heated and vaporized by the heater 10B, exits the vaporizer 3 along with the helium gas introduced after preheating by the preheater 10A via the mass flow controller 1A. The gas exiting the vaporizer 3 is introduced into the reactor 4 together with the hydrogen gas introduced through the mass flow controller 1B and the stop valve 2. The pressure in the reaction system is controlled to a predetermined pressure by opening and closing the valve 6 in front of the vacuum pump, and is monitored by the pressure gauge 5. The central part of the glass reactor has a structure that can be heated by the heater 10C. The copper complex introduced into the reactor is set at the center of the reactor and undergoes reductive pyrolysis on the surface of the deposition target substrate 21 heated to a predetermined temperature by the heater 10C, and a copper thin film is deposited on the substrate 21. To do. The gas exiting the reactor 4 is exhausted to the atmosphere via a trap 7 and a vacuum pump.

  The deposition conditions and deposition results (film characteristics) are shown in Table 1. In addition, as a substrate for vapor deposition, a rectangular substrate having a size of 7 mm × 40 mm was used.

From the results, it can be seen that the copper complexes (1) to (3) of the present invention have better film formability than the conventional copper complex (Cu (sopd) ₂ ).

  According to the present invention, a method for producing a copper-containing thin film using a novel copper complex or a solvent solution of a copper complex by chemical vapor deposition (CVD) can be provided.

It is a figure which shows the structure of a vapor deposition apparatus.

Explanation of symbols

3 Vaporizer 4 Reactor 10B Vaporizer heater 10C Reactor heater 20 Raw material metal complex melt 21 Substrate

Claims (4)

General formula (1)

(In the formula, R ¹ and R ² are (1) R ¹ = ethyl group, R ² = methyl group, (2) R ¹ = ethyl group, R ² = hydrogen atom, (3) R ¹ = t-butyl. Group, R ² = hydrogen atom.)
A novel copper complex (II) represented by   The method for producing a copper-containing thin film according to claim 1, wherein the copper complex according to claim 1 is used.   The manufacturing method of the copper containing thin film of Claim 2 using the solvent solution of the copper complex of Claim 1 as a metal supply source.   The method for producing a copper-containing thin film according to claim 3, wherein the solvent is at least one solvent selected from the group consisting of aliphatic hydrocarbons, aromatic hydrocarbons, and ethers.

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