JP5842687B2 - Cobalt film forming raw material and method for producing cobalt-containing thin film using the raw material - Google Patents

Description

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

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, a bubbling method in which a carrier gas is bubbled into the raw material and the carrier gas and the raw material vapor are entrained on the substrate is generally used as a raw material vapor supply method. In the bubbling method, it is possible to heat the raw material to a constant temperature and stably supply the raw material vapor for the saturated vapor pressure at that temperature.

  On the other hand, as a raw material vapor supply method, the raw material is dissolved in an organic solvent at a constant concentration, the adjusted solution is sent to a high-temperature vaporizer while controlling the flow rate, the entire amount is vaporized, and a constant raw material vapor is supplied. The law is commonly used.

  The bubbling method can easily supply raw material vapor, but long-term heating causes thermal deterioration of the raw material. As a result, it can cause process fluctuations such as fluctuations in the amount of raw material vapor supply and membrane characteristics, making it difficult to use in mass production facilities.

  On the other hand, the solution vaporization method is easier to use for mass production equipment because the raw material is not exposed to long-term heating and can prevent thermal deterioration of the raw material. However, in order to generate a large amount of raw material vapor, it is necessary to prepare a high-concentration solution, and the use is limited to organic solvents with high solubility. In addition, when the optimum raw material is not used, the high-temperature vaporizer causes thermal deterioration of the raw material, which may cause contamination and clogging of the vaporizer. As a result, frequent maintenance of the carburetor is required, leading to a decrease in productivity.

  In the solution vaporization method, since the raw material is diluted in a solvent, the reactivity with the reaction gas becomes insufficient. As a result, compared with the bubbling method, a large amount of reaction gas is used and the film formation rate is reduced, leading to a reduction in productivity.

  On the other hand, there are few reports on solution vaporization supply and solution supply using a cobalt film forming raw material (see, for example, Patent Document 7 and Reference Document 7). When remaining in the film, oxygen-containing solvents such as alcohols and amides that may cause the formation of cobalt oxide are used, and are difficult to use for forming a cobalt metal film. In addition, even if it does not contain oxygen, chain or monocyclic hydrocarbons such as decane, dodecane, tetradecane, toluene, xylene, mesitylene, etc. are usually used from the viewpoint that the cobalt compound only has to be dissolved. (For example, see Patent Document 8).

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)

  However, the raw material for forming a cobalt film, which uses a conventional cobalt compound and dissolves the cobalt compound in a chain or monocyclic hydrocarbon, does not have sufficient vaporization characteristics and reactivity. Thermal degradation is caused and is not necessarily optimal in the production of a cobalt-containing thin film, and it is difficult to say that it is a sufficient raw material for forming cobalt for producing a cobalt-containing thin film. Therefore, there is a demand for a raw material for forming a cobalt film that satisfies any physical properties such as vaporization characteristics and reactivity.

  An object of the present invention is to solve the above-mentioned problems, and to produce a cobalt-containing thin film on a film-forming target by a simple method, and an industrially suitable cobalt film-forming raw material and the cobalt film-forming raw material The manufacturing method of the cobalt containing thin film which uses this is provided.

  The subject of this invention is 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.)
This is solved by a raw material for forming a cobalt film comprising a bis (amidoaminoalkane) cobalt compound represented by formula (II) and a hydrogenated condensed polycyclic hydrocarbon.

  According to the present invention, a raw material for forming a cobalt film suitable for manufacturing a cobalt-containing thin film by a CVD method can be provided, and a method for manufacturing a cobalt-containing thin film using the raw material for forming a cobalt film can be provided.

It is a figure which shows the structure of the vaporization apparatus which evaluates the vaporization characteristic of the raw material for cobalt formation of this invention. 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 raw material for forming a cobalt film of the present invention comprises a bis (amidoaminoalkane) cobalt compound and a hydrogenated condensed polycyclic hydrocarbon. The content of the bis (amidoaminoalkane) cobalt compound in the raw material for forming a cobalt film at this time can be appropriately changed depending on the solubility of the hydrogenated condensed polycyclic hydrocarbon used, but preferably 1 to 40% by mass, More preferably, it is 5 to 30%, and particularly preferably 10 to 30%. By setting it as this range, since sufficient supply capability of a cobalt compound can be provided, a high film-forming speed | rate can be maintained.

(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.

(Hydrogenated condensed polycyclic hydrocarbon)
The condensed polycyclic hydrocarbon hydrogenated in the present invention is at least one hydrogen selected from the group consisting of a partially hydrogenated condensed polycyclic hydrocarbon and a fully hydrogenated condensed polycyclic hydrocarbon. Condensed polycyclic hydrocarbon.

  The partially hydrogenated fused polycyclic hydrocarbon refers to a hydrocarbon containing a saturated site and an unsaturated site simultaneously, wherein the most unsaturated fused polycyclic hydrocarbon is partially hydrogen reduced. Specific examples include hydrocarbons such as indane (dihydroindene), tetralin (tetrahydronaphthalene), fluorene, and acetonaphthene.

  The fully hydrogenated condensed polycyclic hydrocarbon is a polycyclic hydrocarbon not containing an unsaturated site. Specifically, for example, hydrocarbons such as hexahydroindane and decalin (decahydronaphthalene) are used. Can be mentioned.

(Vapor deposition of cobalt-containing thin film)
As a method for depositing a cobalt-containing thin film on a film formation target, a known CVD method or ALD method can be used. For example, a vapor of a cobalt film forming raw material is used as a hydrogen source (for example, under normal pressure or reduced pressure). Hydrogen, reducing gas such as ammonia), nitrogen source (eg, nitrogen, ammonia, etc.) or oxygen source (eg, oxidizing gas such as oxygen, ozone, etc.); water; methanol, ethanol, n-propyl alcohol, isopropyl alcohol, (Alcohols such as n-butyl alcohol) can be used to feed a cobalt-containing thin film by feeding it onto a heated film-forming object together with a single or mixed gas. Note that these gases (including vaporized liquids) may be diluted with an inert gas or the like. Also, 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 the raw material for forming the cobalt film for thin film formation. As a method for vaporizing the raw material for forming the cobalt film used in the present invention, for example, the raw material for forming the cobalt film is pumped with a liquid transport pump. Not only the method of introducing into the vaporizing chamber and vaporizing (solution vaporizing method), but also the method of vaporizing by filling or transporting the cobalt film forming raw material into the vaporizing chamber (bubble method) can be used.

  When depositing a cobalt-containing thin film using the cobalt film-forming raw material 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 100 to 600 ° C., and the temperature at which the cobalt film forming raw material is vaporized is preferably 0 to 250 ° C., more preferably 30 to 200 ° C.

  Note that an oxygen source (for example, oxidizing gas, water vapor or alcohol vapor, or a mixed gas thereof), a nitrogen source (for example, nitrogen gas, ammonia gas, or a mixed gas thereof) with respect to the total gas amount when depositing the cobalt-containing thin film. ) Or a reducing gas (for example, hydrogen gas, ammonia gas, or a mixed gas thereof) 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 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 (vaporization experiment)
Using the raw material for forming a cobalt film composed of the bis (amidoaminoalkane) cobalt compound obtained in Reference Example 3 and a hydrogenated condensed polycyclic hydrocarbon, a vaporization experiment was performed to evaluate the vaporization characteristics.

  The apparatus shown in FIG. 1 was used for the evaluation test. The raw material 20 for forming a cobalt film made of a bis (amidoaminoalkane) cobalt compound and a hydrogenated condensed polycyclic hydrocarbon in the dropping vessel 9 is dropped into the vaporizer 11 heated by the heater 10B, vaporized, and vaporized. Exit vessel 11 The gas exiting the vaporizer 11 passes through a heated vacuum line and is introduced into the recovery unit 12. The temperature in the vaporizer is monitored by a thermometer 13, and the pressure in the system is monitored by a pressure gauge 5.

  In addition, a cobalt compound residue rate shows the ratio of the cobalt compound which remained as a residue in the vaporizer with respect to the used cobalt compound.

Cobalt compound residue ratio (%) = (cobalt compound remaining as residue in vaporizer / cobalt compound used) × 100

Example 1 (Cobalt film forming raw material preparation and vaporization characteristics evaluation)
(Adjustment of raw materials for cobalt film formation)
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 2.33 g and tetralin 9.84 g were mixed and stirred to obtain a cobalt compound content of 19 Obtained 12.17 g of a raw material for forming a cobalt film of 1% by mass.
(Vaporization characteristics evaluation)
Vaporizer temperature: 140-170 ° C
In-system pressure: 1.33-20 Pa
Cobalt film forming raw material: 12.17 g
Dropping time: 30 minutes The cobalt compound residue rate was 3%.

Example 2 (Cobalt film forming raw material preparation and vaporization characteristics evaluation)
(Adjustment of raw materials for cobalt film formation)
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 2.21 g and decalin 14.05 g were mixed and stirred to obtain a cobalt compound content of 13 16.25 g of a raw material for forming a cobalt film of .6% by mass was obtained.
(Vaporization characteristics evaluation)
Vaporizer temperature: 140-170 ° C
In-system pressure: 1.33-20 Pa
Cobalt film forming raw material: 16.25 g
Dropping time: 30 minutes The cobalt compound residue rate was 9%.

Comparative Example 1 (Adjustment of cobalt film forming raw material and evaluation of vaporization characteristics)
(Adjustment of raw materials for cobalt film formation)
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 ′) 2.93 g of cobalt mixture and 10.07 g of ethylcyclohexane were mixed and stirred to obtain a cobalt compound content The raw material for cobalt film formation of 22.7 mass% was obtained 13.00g.
(Vaporization characteristics evaluation)
Vaporizer temperature: 140-170 ° C
In-system pressure: 1.33-20 Pa
Cobalt film forming material: 13.00 g
Dropping time: 30 minutes The cobalt compound residue rate was 13%.

  Comparing Examples 1 and 2 with Comparative Example 1, it can be seen that Examples 1 and 2 have a lower cobalt compound residue ratio in the vaporizer and are excellent as a raw material for forming a cobalt film.

Examples 3 to 6, Reference Examples 4 to 5 and Comparative Examples 2 to 3 (deposition experiment; production of cobalt-containing thin film)
Using the cobalt film forming raw material of the present invention, a vapor deposition experiment by a CVD method was performed to evaluate the film forming characteristics. The deposition conditions and film characteristics are as follows.

  The apparatus shown in FIG. 2 was used for the evaluation test. The cobalt film forming raw material 20 in the vaporizer 3 (glass ampoule) is heated and vaporized by the heater 10B, and is transferred to the helium gas introduced after preheating by the preheater 10A via the mass flow controller 1A. Exit. The gas exiting the vaporizer 3 is introduced into the reactor 4 together with a reaction gas such as ammonia gas, hydrogen gas, oxygen gas or the like 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 3 (Vapor deposition experiment; Production of cobalt-containing thin film)
(Deposition conditions)
Cobalt film forming raw material: Cobalt film forming raw material vaporization temperature prepared in Example 1; 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

Example 4 (Vapor deposition experiment; Production of cobalt-containing thin film)
(Deposition conditions)
Cobalt film forming raw material: Cobalt film forming raw material vaporization temperature prepared in Example 1; 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

Example 5 (Vapor deposition experiment; Production of cobalt-containing thin film)
(Deposition conditions)
Cobalt film forming raw material: Cobalt film forming raw material prepared in Example 2

Evaporation temperature: 90 ° C
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

Example 6 (Vapor deposition experiment; Production of cobalt-containing thin film)
(Deposition conditions)
Cobalt film forming raw material: Cobalt film forming raw material prepared in Example 2

Evaporation 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: 10nm
XPS analysis; cobalt film carbon content: 3%
Nitrogen content; not detected

Reference Example 4 (Vapor deposition experiment; Production of cobalt-containing thin film)
(Deposition conditions)
Cobalt film forming materials:
(Bis (1-t-butylamido-2-dimethylaminopropane-N, N ′) cobalt, bis (2-t-butyramide-1-dimethylaminopropane-N, N ′) cobalt and (1-t-butyramide- 2-dimethylaminopropane-N, N ′) (2-t-butylamido-1-dimethylaminopropane-N, N ′) cobalt mixture 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

Reference Example 5 (Vapor deposition experiment; Production of cobalt-containing thin film)
(Deposition conditions)
Cobalt film forming materials:
(Bis (1-t-butylamido-2-dimethylaminopropane-N, N ′) cobalt, bis (2-t-butyramide-1-dimethylaminopropane-N, N ′) cobalt and (1-t-butyramide- 2-dimethylaminopropane-N, N ′) (2-t-butylamido-1-dimethylaminopropane-N, N ′) cobalt mixture 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: 10nm
XPS analysis; cobalt film carbon content: 3%
Nitrogen content; not detected

Comparative Example 2 (deposition experiment; production of cobalt-containing thin film)
Cobalt film forming materials:
Bis (N-tert-butyl-N′-ethylpropionamidinato) cobalt (compound described in Patent Document 6)

(Deposition conditions)
Evaporation temperature: 90 ° C
He carrier flow rate: 10 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 properties (SEM and XPS-depth measurement))
Film thickness: 40nm
XPS analysis; cobalt film carbon content: 3% (in terms of carbon atoms)
Nitrogen content: 7% (nitrogen atom conversion)

Comparative Example 3 (Vapor deposition experiment; Production of cobalt-containing thin film)
Cobalt film forming materials:
Bis (N-tert-butyl-N′-ethylpropionamidinato) cobalt (compound described in Patent Document 6)

(Deposition conditions)
Evaporation temperature: 90 ° C
He carrier flow rate: 10 sccm
Dilution He 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 properties (SEM and XPS-depth measurement))
Film thickness: 0 nm (film formation was not seen)

  When Examples 3 to 6 and Reference Examples 4 to 5 are compared, it can be seen that the film formation rate and film quality are equivalent, and both are excellent as a cobalt film forming raw material. Moreover, when Examples 3-6 and Reference Examples 4-5 are compared with Comparative Examples 2-3, Examples 3-6 and Reference Examples 4-5 have better film formation rates and better film quality, and a cobalt film is formed. It turns out that it is excellent as a raw material.

  From the above results, the raw material for forming a cobalt film of the present invention is a raw material for producing a high-quality cobalt-containing thin film that has little residue in the vaporizer, is highly reactive, and does not contain impurities such as carbon and nitrogen. It turns out to get. Among them, a cobalt film-forming raw material comprising a cobalt compound and tetralin which is a partially hydrogenated condensed polycyclic hydrocarbon showed better results.

  The present invention relates to a raw material for forming a cobalt film and a method for producing a cobalt-containing thin film on a film formation target by a CVD method using the raw material for forming a cobalt film.

3 Vaporizer 4 Reactor 7 Trap 10 B Vaporizer heater 10 C Reactor heater 20 Cobalt film forming raw material 21 Substrate

Claims (6)

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 raw material for forming a cobalt film comprising a bis (amidoaminoalkane) cobalt compound represented by the formula (II) and a hydrogenated condensed polycyclic hydrocarbon.   At least one hydrogenated condensation wherein the hydrogenated fused polycyclic hydrocarbon is selected from the group consisting of a partially hydrogenated fused polycyclic hydrocarbon and a fully hydrogenated fused polycyclic hydrocarbon The raw material for forming a cobalt film according to claim 1, which is a polycyclic hydrocarbon.   The raw material for forming a cobalt film according to claim 1, wherein the partially hydrogenated condensed polycyclic hydrocarbon is indane, tetralin, fluorene, or acetonaphthene.   The raw material for forming a cobalt film according to claim 1, wherein the fully hydrogenated condensed polycyclic hydrocarbon is hexahydroindane or decalin (decahydronaphthalene).   The raw material for forming a cobalt film according to claim 1, wherein the content of the bis (amidoaminoalkane) cobalt compound in the raw material for forming the cobalt film is 1 to 40% by mass.   The manufacturing method of the cobalt containing thin film by the chemical vapor deposition method using the raw material for cobalt film formation of Claim 1.

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