JP5825169B2 - Method for producing cobalt-containing thin film - Google Patents

Description

  The present invention relates to a method for producing a cobalt-containing thin film on a film formation target by a chemical vapor deposition method (hereinafter referred to as a CVD method) using a novel cobalt compound.

  In recent years, many researches and developments have been made on cobalt-containing thin films as materials in the fields of semiconductors and electronic components. Examples of cobalt compounds for producing thin films that have been proposed so far include, for example, bis (acetylacetonato) cobalt (see, for example, Non-Patent Document 1) and bis (dipivaloylmethanato) cobalt (for example, Non-Patent Document 4). ), Octacarbonyldicobalt (for example, see Non-patent Document 2 and Patent Document 1), cobalt cyclopentadienyl dicarbonyl (for example, see Non-patent Document 3 and Patent Document 2) and bis (trimethylsilylcyclopentadienyl) cobalt (See, for example, Patent Document 3), bis (N, N′-diisopropylacetamidinato) cobalt (see, for example, Patent Document 4, Patent Document 5, and Non-Patent Document 5), Bis (N-tert-butyl-N '-Ethylpropionamidinato) cobalt (see, for example, Patent Document 6 and Non-Patent Document 6) is disclosed. .

  By the way, in the CVD method, when forming a metal cobalt film, a reducing agent is used to reduce the divalent cobalt compound to zero. For example, bis (acetylacetonato) cobalt (see, for example, Non-Patent Document 1 and Non-Patent Document 7) uses a large amount of hydrogen or n-propanol at normal pressure. Bis (N, N′-diisopropylacetamidinato) cobalt (see, for example, Patent Document 4, Patent Document 5 and Non-Patent Document 5), Bis (N-tert-butyl-N′-ethylpropionamidinato) cobalt (For example, see Patent Document 6 and Non-Patent Document 6), the substrate temperature is set to 300 ° C., and hydrogen and ammonia are similarly used as the reducing agent.

Furthermore, cobalt cyclopentadienyl dicarbonyl (see, for example, Non-Patent Document 3 and Patent Document 2) and octacarbonyldicobalt (see, for example, Non-Patent Document 2 and Patent Document 1) are monovalent and zero-valent cobalt compounds. However, since a large amount of ligand-derived carbon and oxygen components remain in the film, hydrogen whose energy has been excited by plasma is used as a reducing agent or removal of carbon and oxygen components in the film.

  However, when a large amount of hydrogen is used, there is a problem in safety due to its explosive nature. Moreover, when the substrate temperature is set to a high temperature of 300 ° C. or higher, the morphology (flatness) of the metal cobalt film is deteriorated. Furthermore, in order to avoid the deterioration of the substrate due to high temperature, the substrate type is limited, which is not preferable. Similarly, in the method of exciting hydrogen energy with plasma, degradation of the substrate due to plasma cannot be ignored, so that the types of deposition substrates are limited.

  An oxygen-containing reducing agent such as n-propyl alcohol, when remaining in the film, becomes an oxygen component and can produce cobalt oxide, and therefore should not be used when forming a cobalt metal film. On the other hand, a method of using ammonia as a reducing agent has also been proposed, but cobalt nitride is generated by the nitrogen component of ammonia, so that a large amount of ammonia is not preferable.

US Patent Application Publication No. 2005/0130417 US Patent Application Publication No. 2006/0157863 International Publication No. 2008/111499 Pamphlet International Publication No. 2004/046417 Pamphlet International Publication No. 2009/085522 Pamphlet Special table 2010-524264 gazette JP 2009-1896 A JP-T-2006-511716

Japan Journal of Applied Physics, vol. 36,705 (1997) Thin Solid Films, vol. 485, 95 (2005) Japan Journal of Applied Physics, vol. 46,173 (2007) Chemistry of Materials, vol. 13, 588 (2001) Journal of The Electrochemical Society, vol. 157, D10-D15 (2010) Dalton Transactions, 2008, 2592-2597 Chemistry of Materials, vol. 19, 6206 (2007)

  A conventional method for producing a cobalt-containing thin film has severe film formation conditions such as a substrate temperature and a reducing gas and has poor film quality, and is not necessarily optimal in the production of a cobalt-containing thin film, and is hardly suitable for mass production. Therefore, there is a demand for a method for producing a cobalt compound and a cobalt-containing thin film that satisfies any of the requirements of process conditions and film quality.

  An object of the present invention is to solve the above-mentioned problems and provide a cobalt compound suitable for the production of a cobalt-containing thin film on a film-forming object by a simple method, and an industrially suitable cobalt-containing thin film. A manufacturing method is provided.

  The subject of the present invention is a general formula (1) in the presence of a partially hydrogenated fused polycyclic hydrocarbon.

(In the formula, R ¹ represents a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, and R ² and R ³ may be the same or different. A chain or branched alkyl group, wherein R ² and R ³ may be bonded to each other to form a ring, and Z represents a linear or branched alkylene group having 1 to 5 carbon atoms; Show.)
It solves by the manufacturing method of the cobalt containing thin film by the chemical vapor deposition method characterized by using the bis (amido amino alkane) cobalt compound shown by these as a cobalt supply source.

  According to the present invention, a cobalt compound suitable for the production of a cobalt-containing thin film by a CVD method can be provided, and a method for producing a cobalt-containing thin film using the cobalt compound can be provided.

It is a figure which shows the structure of the vapor deposition apparatus which manufactures a cobalt containing thin film using the raw material for cobalt formation of this invention.

  The present invention produces a cobalt-containing thin film by chemical vapor deposition using a bis (amidoaminoalkane) cobalt compound as a cobalt source in the presence of a partially hydrogenated condensed polycyclic hydrocarbon. Composed.

(Bis (amidoaminoalkane) cobalt compound)
The bis (amidoaminoalkane) cobalt compound of the present invention is represented by the general formula (1). In the general formula (1), R ¹ has 1 carbon atom such as methyl group, ethyl group, n-propyl group, isopropyl group, cyclopropyl group, t-butyl group, cyclobutyl group, t-pentyl group, neopentyl group and the like. -6 linear, branched or cyclic alkyl groups are shown.

R ² and R ³ may be the same or different and each represents a linear or branched alkyl group having 1 to 3 carbon atoms such as a methyl group, an ethyl group, a propyl group, or an isopropyl group. R ² and R ³ may be bonded to each other to form a ring.

  Z represents a linear or branched alkylene group having 1 to 5 carbon atoms such as a methylene group, an ethylene group, a trimethylene group, a methylethylene group, a tetraethylene group, a 2-methyltrimethylene group, and a hexamethylene group. Show.

In a preferred embodiment of the present invention, R ¹ is an alkyl group having 2 to 5 carbon atoms, R ² and R ³ are alkyl groups having 1 to 2 carbon atoms, and Z is an alkylene group having 1 to 3 carbon atoms. It is.

  The bis (amidoaminoalkane) cobalt compound (1) of the present invention is synthesized by the method shown below. Specifically, the alkylalkali metal compound (2) and the diaminoalkane compound (3) are reacted. (Amidoaminoalkane) An alkali metal compound (4) is obtained (hereinafter also referred to as reaction (A)), and then this is reacted with a dihalogenocobalt compound (5) (hereinafter referred to as reaction (B)). The reaction (A) and the reaction (B) are collectively referred to as the reaction of the present invention.

(Wherein R ¹ , R ² , R ³ , R ⁴ , X and Z are as defined above.)

(Reaction (A); (Amidaminoalkane) Synthesis of Alkali Metal Compound (4))
The alkyl alkali metal compound used in the reaction (A) of the present invention is represented by the general formula (2). In the general formula (2), R ⁴ is methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, n-pentyl group, t-pentyl group, neopentyl. A linear or branched alkyl group having 1 to 10 carbon atoms such as a group or an n-decyl group, and M represents an alkali metal such as a lithium atom, a sodium atom or a potassium atom; In addition, you may use these alkyl alkali metal compounds individually or in mixture of 2 or more types.

  As the alkyl alkali metal compound, methyl lithium and n-butyl lithium are preferably used.

The diaminoalkane compound used in the reaction (A) of the present invention is represented by the general formula (3). In the general formula (1), R ¹ , R ² , R ³ and Z are as defined above. Specifically, 1-ethylamino-2-dimethylaminoethane, 1-isopropylamino-2-dimethylaminoethane, 1- (t-butylamino) -2-dimethylaminoethane, 1-isobutylamino- 2-dimethylaminoethane, 1-dimethylamino-2- (t-pentylamino) ethane, 1-isopropylamino-3-dimethylaminopropane, 1- (t-butylamino) -3-dimethylaminopropane, (isopropylamino) ) (Dimethylamino) methane, (t-butylamino) (dimethylamino) methane and the like are preferably used.

  The diaminoalkane compound used in the reaction (A) of the present invention can be produced by combining a commercially available product or a known method. For example, halogenation having a monoalkylamine and a “dialkylamino group” in the structure. A method using alkane hydrochloride or a reduction reaction of the corresponding imine compound is preferably employed.

  The amount of the diaminoalkane compound to be used is preferably 1.5 to 3.0 mol, more preferably 1.8 to 2.2 mol, per 1 mol of the alkyl alkali metal compound.

  The reaction (A) of the present invention is preferably carried out in an organic solvent, and the organic solvent used is not particularly limited as long as it does not inhibit the reaction. For example, diethyl ether, tetrahydrofuran, dimethoxyethane, dioxane, etc. Ethers; aliphatic hydrocarbons such as hexane, heptane, octane, cyclohexane, methylcyclohexane, and ethylcyclohexane; and aromatic hydrocarbons such as toluene and xylene, preferably ethers, aliphatic hydrocarbons, A mixed solvent of ethers and aliphatic hydrocarbons is used. In addition, you may use these organic solvents individually or in mixture of 2 or more types.

  The amount of the organic solvent used is preferably 1 to 100 g, more preferably 1 to 10 g, relative to 1 g of the alkyl alkali metal compound.

  The reaction (A) of the present invention is performed, for example, by a method of adding an organic solvent solution of an alkylalkali metal compound and reacting them while stirring a mixture of a diaminoalkane compound and an organic solvent. The reaction temperature at that time is preferably −78 to 120 ° C., more preferably −20 to 60 ° C., and the reaction pressure is not particularly limited.

(Reaction (B); synthesis of bis (amidoaminoalkane) cobalt compound (1))
The dihalogenocobalt compound used in the reaction (B) of the present invention is represented by the general formula (5). In the general formula (5), X represents a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom or an iodine atom.

  As the dihalogenocobalt compound, cobalt (II) chloride, cobalt (II) bromide, and cobalt (II) iodide are preferably used.

  The amount of the dihalogenocobalt compound used is preferably 0.25 to 0.75 mol, more preferably 0.4 to 0.6 mol, with respect to 1 mol of the (amidoaminoalkane) alkali metal compound.

  The reaction (B) of the present invention is preferably carried out in an organic solvent, and the organic solvent to be used is not particularly limited as long as it does not inhibit the reaction, but examples thereof include diethyl ether, tetrahydrofuran, dimethoxyethane, dioxane and the like. Ethers; aliphatic hydrocarbons such as hexane, heptane, octane, cyclohexane, methylcyclohexane, and ethylcyclohexane; and aromatic hydrocarbons such as toluene and xylene, preferably ethers, aliphatic hydrocarbons, A mixed solvent of ethers and aliphatic hydrocarbons is used. In addition, you may use these organic solvents individually or in mixture of 2 or more types.

  The amount of the organic solvent to be used is preferably 1 to 100 g, more preferably 1 to 10 g, relative to 1 g of the (amidoaminoalkane) alkali metal compound.

  In the reaction (B) of the present invention, for example, an organic solvent solution of the (amidoaminoalkane) alkali metal compound obtained in the reaction (A) is added while stirring a mixture of a dihalogenocobalt compound and an organic solvent. It is carried out by a method such as reacting. The reaction temperature at that time is preferably −78 to 120 ° C., more preferably −20 to 60 ° C., and the reaction pressure is not particularly limited.

  The target bis (amidoaminoalkane) cobalt compound is obtained by the reaction (B) of the present invention. After the reaction is completed, for example, extraction, filtration, concentration, distillation, sublimation, recrystallization, column chromatography, etc. are known. It is isolated and purified by this method.

  In carrying out the reaction (A) and the reaction (B) in the present invention, the (amidoaminoalkane) alkali metal compound (4) obtained as a result of the reaction (A) is isolated, for example, by using the same solvent. It can also be synthesized continuously without purification.

  The target product, bis (amidoaminoalkane) cobalt compound, its starting material, alkylalkali metal compound, and synthetic intermediate, (amidoaminoalkane) alkylmetal compound, are insensitive to moisture and oxygen in the atmosphere. Since it is often stable, it is desirable to perform a reaction operation or a post-treatment of the reaction solution under anhydrous conditions or in an inert gas atmosphere. Further, it is desirable that the starting materials, the solvent, and the like are dehydrated and dried in advance before use.

  Examples of the bis (amidoaminoalkane) cobalt compound produced by the reaction of the present invention include compounds represented by the following formulas (6) to (41) and mixtures thereof.

(Partially hydrogenated condensed polycyclic hydrocarbon)
The partially hydrogenated condensed polycyclic hydrocarbon in the present invention is a hydrocarbon containing a saturated portion and an unsaturated portion simultaneously, wherein the most unsaturated condensed polycyclic hydrocarbon is partially hydrogen reduced. Specifically, for example, hydrocarbons such as indane (dihydroindene), tetralin (tetrahydronaphthalene), fluorene, acetonaphthene and the like can be mentioned. In addition, the partially hydrogenated condensed polycyclic hydrocarbon may be used alone or in combination of two or more.

  These partially hydrogenated condensed polycyclic hydrocarbons are converted to unsaturated condensed polycyclic hydrocarbons by supplying hydrogen during the formation of the cobalt film.

  The amount of the partially hydrogenated condensed polycyclic hydrocarbon is preferably 0.1 to 100 mol, more preferably 1 to 50 mol, per 1 mol of the cobalt compound.

(Vapor deposition of cobalt-containing thin film)
As a method for depositing a cobalt-containing thin film on a film formation target, it can be performed by a known CVD method or ALD method. For example, a film formation target obtained by heating a vapor of a cobalt compound under normal pressure or reduced pressure. It is possible to use a method in which a cobalt-containing thin film is vapor-deposited. These gases (including vaporized liquids) may be diluted with an inert gas (helium, argon, nitrogen, etc.), a hydrogen source (for example, a reducing gas such as hydrogen, ammonia, etc.), alone or A gas obtained by mixing a plurality of gases may be used. A cobalt-containing thin film can be deposited by plasma CVD using the same raw material supply.

  In the CVD method, it is necessary to vaporize a cobalt compound in order to form a thin film. As a method for vaporizing a cobalt compound used in the present invention, for example, a cobalt compound is introduced into a vaporization chamber by a liquid transport pump. Not only the method of vaporization (solution vaporization method) but also the method of vaporizing by filling or transporting a cobalt compound into the vaporization chamber (bubbling method) can be used.

  In the case of depositing a cobalt-containing thin film using the cobalt compound of the present invention, as the deposition conditions, for example, the pressure in the reaction system is preferably 1 Pa to 200 kPa, and the film formation target temperature is preferably 50 to 900 ° C. More preferably, the temperature at which the cobalt compound is vaporized is preferably from 0 to 250 ° C, more preferably from 30 to 200 ° C.

  In addition, the content ratio of an inert gas (for example, helium gas, argon gas, nitrogen gas) or a reducing gas (for example, hydrogen gas, ammonia gas, or a mixed gas thereof) with respect to the total gas amount when depositing a cobalt-containing thin film Is preferably 3 to 99% by volume, more preferably 5 to 98% by volume.

  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 1-t-butylamino-2-dimethylaminopropane and 2-t-butylamino-1-dimethylaminopropane mixture)

  2- (Dimethylamino) propane chloride hydrochloride 25.0 g (158 mmol), t-butylamine 69.4 g (949 mmol) and water 3 ml were added to a 300 ml flask equipped with a stirrer and a thermometer and stirred. The reaction was carried out at 60 ° C. for 10 hours. After completion of the reaction, the reaction mixture was filtered and washed with 200 ml of hexane, and the hexane layer was concentrated under reduced pressure. The resulting concentrate was distilled under reduced pressure (120 ° C., 12 kPa) to give a mixture of 1-t-butylamino-2-dimethylaminopropane and 2-t-butylamino-1-dimethylaminopropane (mixing ratio 8: 2). 19.2 g was obtained (isolated yield; 77%).

  The physical property values of the 1-t-butylamino-2-dimethylaminopropane and 2-t-butylamino-1-dimethylaminopropane mixture were as follows.

¹ H-NMR (CDCl ₃ , δ (ppm)); 0.89 (3H, t, 6.5 Hz), 1.10 (9H, s), 1.40 (1H, brs), 2.18 (6H , S), 2.38 (1 H, m), 2.53 (1 H, t, 11.0 Hz), 2.48 (3 H, m), 2.67 to 2.77 (1 H, m)

Reference Example 2 (Synthesis of (1-t-butylamido-2-dimethylaminopropane-N, N ′) lithium and 2-t-butylamido-1-dimethylaminopropane-N, N ′) lithium mixture)

  1-t-Butylamino-2-dimethylaminopropane and 2-t-butylamino- obtained in Reference Example C7 were placed in a 50-ml flask equipped with a stirrer, a thermometer and a dropping funnel in an argon atmosphere. A mixture of 1-dimethylaminopropane (mixing ratio 8: 2) 3.15 g (19.9 mmol) and hexane 15 ml were added. Subsequently, 10 ml (16.5 mmol) of a hexane solution of 1.65 mol / l n-butyllithium was slowly dropped while maintaining the mixed solution at 0 ° C. After the dropwise addition, the mixed solution was stirred at 0 ° C. for 30 minutes and then reacted at 20 ° C. for 2 hours with stirring. After completion of the reaction, the reaction solution was concentrated under reduced pressure, and then the concentrate was dried under vacuum to give 1-t-butylamido-2-dimethylaminopropane-N, N ′) lithium and 2-t-butylamide-1 A mixture of -dimethylaminopropane-N, N ') lithium was obtained.

  The 1-t-butylamido-2-dimethylaminopropane-N, N ′) lithium and 2-t-butylamido-1-dimethylaminopropane-N, N ′) lithium mixture were used as they were in the next reaction.

Reference Example 3 (bis (1-t-butylamido-2-dimethylaminopropane-N, N ′) cobalt (cobalt compound (21)), bis (2-t-butylamido-1-dimethylaminopropane-N, N ′ ) Cobalt (cobalt compound (28)) and (1-t-butylamido-2-dimethylaminopropane-N, N ′) (2-t-butylamido-1-dimethylaminopropane-N, N ′) cobalt (cobalt compound) (35)) Synthesis of mixture)

  In an argon atmosphere, 1.07 g (8.25 mmol) of anhydrous cobalt (II) chloride and 20 ml of tetrahydrofuran were added to a flask having an internal volume of 100 ml equipped with a stirrer, a thermometer and a dropping funnel, and stirred for 2 hours. Next, tetrahydrofuran of 1-t-butylamido-2-dimethylaminopropane-N, N ′) lithium and 2-t-butylamido-1-dimethylaminopropane-N, N ′) lithium obtained in Reference Example C8 20 ml of the solution was dropped gently while keeping the liquid temperature at 0 ° C., and then reacted at 20 ° C. for 6 hours with stirring. After completion of the reaction, the reaction solution was concentrated under reduced pressure, and 100 ml of hexane was added to the resulting concentrate and stirred. After filtration, the filtrate was concentrated under reduced pressure, and the concentrate was distilled under reduced pressure (115 ° C., 13.3 Pa) to give bis (1-tert-butylamido-2-dimethylaminopropane-N, as a dark brown solid. N ′) cobalt, bis (2-t-butyramide-1-dimethylaminopropane-N, N ′) cobalt and (1-t-butyramide-2-dimethylaminopropane-N, N ′) (2-t-butyramide) 2.9 g of (-1-dimethylaminopropane-N, N ′) cobalt mixture was obtained (isolation yield; 94%).

  In addition, bis (1-t-butylamido-2-dimethylaminopropane-N, N ′) cobalt, bis (2-t-butylamido-1-dimethylaminopropane-N, N ′) cobalt and (1-t-butylamide) 2-dimethylaminopropane-N, N ′) (2-t-butylamido-1-dimethylaminopropane-N, N ′) cobalt mixture is a novel compound represented by the following physical property values.

Melting point: 90 ° C
Cobalt content by inductively coupled plasma (ICP) analysis; 15.0% by mass
(Calculated value: 15.8% by mass)

Examples 1-2 and Comparative Examples 1-2 (deposition experiment; production of cobalt-containing thin film)
Using the bis (amidoaminoalkane) cobalt compound of the present invention, a vapor deposition experiment by a CVD method was performed in the presence of a partially hydrogenated condensed polycyclic hydrocarbon to evaluate the film forming characteristics. The deposition conditions and film characteristics are as follows.

  The apparatus shown in FIG. 1 was used for the evaluation test. The bis (amidoaminoalkane) cobalt compound and the partially hydrogenated condensed polycyclic hydrocarbon 20 in the vaporizer 3 (glass ampule) are heated and vaporized by the heater 10B, and the preheater passes through the mass flow controller 1A. After being preheated at 10A, it is introduced into the helium gas introduced and exits the vaporizer 3. The gas exiting the vaporizer 3 is introduced into the reactor 4 together with a reaction gas such as ammonia gas or hydrogen gas introduced via 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 reactor has a structure that can be heated by a heater 10C. The cobalt compound introduced into the reactor is set at the center of the reactor and reduced or oxidized by thermal decomposition on the surface of the deposition substrate 21 heated to a predetermined temperature by the heater 10C. A thin film is deposited. The gas exiting the reactor 4 is exhausted to the atmosphere via a trap 7 and a vacuum pump.

  Deposition conditions and film characteristics were as follows. Note that a 6 mm × 20 mm rectangular substrate was used as the deposition substrate.

Example 1 (deposition experiment; production of cobalt-containing thin film)
(Deposition conditions)
Cobalt compounds: bis (1-t-butylamido-2-dimethylaminopropane-N, N ′) cobalt, bis (2-t-butylamido-1-dimethylaminopropane-N, N ′) cobalt and (1-t- Butyramido-2-dimethylaminopropane-N, N ′) (2-t-butylamido-1-dimethylaminopropane-N, N ′) cobalt mixture partially hydrogenated condensed polycyclic hydrocarbon: tetralin vaporization temperature; 90 ° C
He carrier flow rate: 30 sccm
Ammonia flow rate: 1 sccm
Dilution He flow rate: 9sccm
Substrate material; SiO ₂ / Si wafer substrate temperature; 200 ° C.
Reaction system pressure: 0.67 kPa
Deposition time: 5 minutes

(Membrane characteristics (SEM and XPS-depth measurement))
Film thickness: 200nm
XPS analysis; cobalt film carbon content; not detected; nitrogen content; not detected

The amount of naphthalene produced trapped from the exhaust gas was 0.042 g (3.12 × 10 ⁻⁵ mol). On the other hand, the amount of the cobalt compound used was 8.60 × 10 ⁻⁵ mol (calculated from the amount of the produced cobalt-containing thin film).
From the above results, it was found that 0.36 mol of tetralin was involved in the film formation (involved as a hydrogen source) with respect to 1 mol of the cobalt compound.

Example 2 (Vapor deposition experiment; Production of cobalt-containing thin film)
(Deposition conditions)
Cobalt compounds: bis (1-t-butylamido-2-dimethylaminopropane-N, N ′) cobalt, bis (2-t-butylamido-1-dimethylaminopropane-N, N ′) cobalt and (1-t- Butyramido-2-dimethylaminopropane-N, N ′) (2-t-butylamido-1-dimethylaminopropane-N, N ′) cobalt mixture partially hydrogenated condensed polycyclic hydrocarbon: tetralin vaporization temperature; 90 ° C
He carrier flow rate: 30 sccm
Dilution He flow rate: 10sccm
Substrate material; SiO ₂ / Si wafer substrate temperature; 200 ° C.
Reaction system pressure: 0.67 kPa
Deposition time: 5 minutes

(Membrane characteristics (SEM and XPS-depth measurement))
Film thickness: 50nm
XPS analysis; cobalt film carbon content; not detected; nitrogen content; not detected

The amount of naphthalene produced trapped from the exhaust gas was 0.042 g (3.12 × 10 ⁻⁵ mol). On the other hand, the amount of cobalt compound used was 2.15 × 10 ⁻⁵ mol (calculated from the amount of produced cobalt-containing thin film).
From the above results, it was found that 1.45 mol of tetralin was involved in the film formation (involved as a hydrogen source) with respect to 1 mol of the cobalt compound.

Comparative Example 1 (deposition experiment; production of a cobalt-containing thin film)
(Deposition conditions)
Cobalt compounds: bis (1-t-butylamido-2-dimethylaminopropane-N, N ′) cobalt, bis (2-t-butylamido-1-dimethylaminopropane-N, N ′) cobalt and (1-t- Butylamido-2-dimethylaminopropane-N, N ′) (2-t-butylamido-1-dimethylaminopropane-N, N ′) cobalt mixture fully hydrogenated condensed polycyclic hydrocarbon: decalin vaporization temperature; 90 ℃
He carrier flow rate: 30 sccm
Ammonia flow rate: 10 sccm
Substrate material; SiO ₂ / Si wafer substrate temperature; 200 ° C.
Reaction system pressure: 0.67 kPa
Deposition time: 5 minutes

(Membrane characteristics (SEM and XPS-depth measurement))
Film thickness: 200nm
XPS analysis; cobalt film carbon content; not detected; nitrogen content; not detected In addition, when exhaust gas was analyzed, tetralin and naphthalene from which decalin was dehydrogenated were not detected (that is, decalin was involved as a hydrogen source). )

Comparative Example 2 (deposition experiment; production of cobalt-containing thin film)
(Deposition conditions)
Cobalt compounds: bis (1-t-butylamido-2-dimethylaminopropane-N, N ′) cobalt, bis (2-t-butylamido-1-dimethylaminopropane-N, N ′) cobalt and (1-t- Butylamido-2-dimethylaminopropane-N, N ′) (2-t-butylamido-1-dimethylaminopropane-N, N ′) cobalt mixture fully hydrogenated condensed polycyclic hydrocarbon: decalin vaporization temperature; 90 ℃
He carrier flow rate: 30 sccm
Dilution He flow rate: 10sccm
Substrate material; SiO ₂ / Si wafer substrate temperature; 200 ° C.
Reaction system pressure: 0.67 kPa
Deposition time: 5 minutes

(Membrane characteristics (SEM and XPS-depth measurement))
Film thickness: 10nm
XPS analysis; cobalt film carbon content: 3%
Nitrogen content: not detected Note that when exhaust gas was analyzed, tetralin and naphthalene from which decalin was dehydrogenated were not detected (that is, decalin was not involved as a hydrogen source).

  From the above results, when producing a cobalt film using the bis (amidoaminoalkane) cobalt compound of the present invention as a cobalt source, the reaction is carried out in the presence of a partially hydrogenated condensed polycyclic hydrocarbon. As a result, a high-quality cobalt-containing thin film that does not contain impurities such as carbon and nitrogen can be produced.

  The present invention relates to a method for producing a cobalt-containing thin film on a film formation object by a CVD method using a bis (amidoaminoalkane) cobalt compound in the presence of a partially hydrogenated condensed polycyclic hydrocarbon. .

7 trap 10B vaporizer heater 20 liquid mixture of bis (amidoaminoalkane) cobalt compound and partially hydrogenated condensed polycyclic hydrocarbon

Claims (2)

In the presence of a partially hydrogenated fused polycyclic hydrocarbon, the general formula (1)

(In the formula, R ¹ represents a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, and R ² and R ³ may be the same or different. A chain or branched alkyl group, wherein R ² and R ³ may be bonded to each other to form a ring, and Z represents a linear or branched alkylene group having 1 to 5 carbon atoms; Show.)
A method for producing a cobalt-containing thin film by chemical vapor deposition, wherein a bis (amidoaminoalkane) cobalt compound represented by the formula (1) is used as a cobalt supply source.   The method for producing a cobalt-containing thin film according to claim 1, wherein the partially hydrogenated condensed polycyclic hydrocarbon is indane, tetralin, fluorene, or acetonaphthene.

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