JP6116007B2 - Thin film forming raw material and thin film manufacturing method - Google Patents

Description

  The present invention relates to a thin film forming raw material containing a silicon compound having a specific structure, and a thin film manufacturing method for forming a thin film containing silicon and phosphorus using the raw material.

  A thin film material containing silicon and phosphorus is a material used for embedding an insulating film or an isolation groove in an electronic device such as a semiconductor device. In order to realize high speed and high integration of the electronic device, methods for producing a thin film material containing silicon and phosphorus by various methods are being studied.

  Examples of the method for producing the thin film include a MOD method such as a coating pyrolysis method and a sol-gel method, a chemical vapor deposition method, and the like. Since it has many advantages such as excellent composition controllability, step coverage, suitable for mass production, and capable of hybrid integration, chemical vapor deposition including ALD (Atomic Layer Deposition) (hereinafter, The method may be simply described as CVD), and the ALD method is an optimal process because it is particularly excellent in step coverage.

  Conventionally, various raw materials for CVD methods are known as raw materials for CVD methods used for producing a thin film material containing silicon and phosphorus. For example, a method using oxygen as an oxidizing agent, monosilane as a silicon raw material, and phosphine as a phosphorus raw material is known, but there is a problem that the step coverage of the resulting film is poor. Among these, since phosphine is a compound having a property of spontaneous ignition and extremely toxic properties, a method using no phosphine has been desired. Therefore, as a method that is currently in practical use, there is known a method using ozone as an oxidizing agent, alkoxysilane as a silicon raw material, and trialkylphosphine, trialkyl phosphite, or trialkyl phosphate as a phosphorus raw material. However, even with this method, it has not been possible to form a thin film material excellent in step coverage enough to cope with higher density and higher integration. In order to solve these problems, Patent Document 1 discloses a raw material for CVD using a specific silicon compound containing a silicon atom and a phosphorus atom in the structure.

JP 08-133754 A

  The properties required of a thin film forming raw material used to form a thin film by vaporizing a compound such as a CVD method are low melting point and can be transported in a liquid state, low liquid viscosity, vapor pressure Are easy to vaporize, have high thermal stability, and can obtain a thin film having a desired composition. As a method of obtaining a thin film containing silicon and phosphorus by the CVD method, a method in which each of a silicon raw material and a phosphorus raw material is prepared as in the publicly-known technique described above, or a specific method containing a silicon atom and a phosphorus atom in the structure. A method using a silicon compound is known. In the method in which each of the silicon raw material and the phosphorus raw material is prepared, since the viscosity, vapor pressure and thermal stability of each raw material are different, it is difficult to control the raw material supply and the productivity is a big problem. . In a conventionally known method using a specific silicon compound containing a silicon atom and a phosphorus atom in the structure, the thermal stability of the silicon compound to be used is low, or the phosphorus content is 10 to 20 only with the silicon compound. There are problems that a thin film of mass% cannot be obtained, that the reactivity with the reactive gas is poor, and that it cannot be applied to an ALD process having excellent step coverage. Therefore, the raw material for forming a thin film that can obtain a thin film containing silicon and phosphorus having a high thermal stability and a phosphorus content of 10 to 20% by mass, is excellent in reactivity with a reactive gas, and has a step coating. There is a demand for a raw material for forming a thin film that can be applied to an ALD method having excellent properties. Regarding conventional thin film forming raw materials, there has been no thin film forming raw material that is sufficiently satisfactory in these respects.

  As a result of repeated studies, the present inventor has found that a raw material for forming a thin film containing a silicon compound having a specific structure can solve the above problems, and has reached the present invention.

  This invention provides the raw material for thin film formation containing the silicon compound represented by following General formula (1).

（式中、Ｒ¹〜Ｒ³は各々独立に炭素数１〜４のアルキル基を表し、Ｘは下記（Ｘ−１）〜（Ｘ−５）の何れかで表される基を表す。）

(In the formula, R ^{1 to} R ³ each independently represents an alkyl group having 1 to 4 carbon atoms, and X represents a group represented by any one of the following (X-1) to (X-5).)

（式中、Ｒ⁴〜Ｒ⁶は各々独立に炭素数１〜４のアルキル基を表し、Ｒ⁷〜Ｒ¹⁰は各々独立に炭素数１または２のアルキル基を表し、Ｒ¹¹はイソプロピル基または第３ブチル基を表す。）

(Wherein R ^{4 to} R ⁶ each independently represents an alkyl group having 1 to 4 carbon atoms, R ^{7 to} R ¹⁰ each independently represents an alkyl group having 1 or 2 carbon atoms, and R ¹¹ represents an isopropyl group or Represents a tertiary butyl group.)

  Also, the present invention introduces a vapor containing the silicon compound obtained by vaporizing the raw material for forming a thin film into a film forming chamber in which a substrate is installed, and decomposes and / or chemically reacts the silicon compound. The present invention also provides a method for producing a thin film in which a thin film containing silicon and phosphorus is formed on the surface of the substrate.

  ADVANTAGE OF THE INVENTION According to this invention, the raw material for thin film formation which can be applied to the ALD method which is high in thermal stability, excellent in reactivity with reactive gas, and excellent in step coverage can be provided. Moreover, the raw material for thin film formation which can obtain the thin film whose phosphorus content is 10-20 mass% can be provided.

FIG. 1 is a schematic view showing an example of an apparatus for chemical vapor deposition used in a method for producing a thin film containing silicon and phosphorus according to the present invention. FIG. 2 is a schematic view showing another example of an apparatus for chemical vapor deposition used in the method for producing a thin film containing silicon and phosphorus according to the present invention. FIG. 3 is a schematic view showing another example of an apparatus for chemical vapor deposition used in the method for producing a thin film containing silicon and phosphorus according to the present invention. FIG. 4 is a schematic view showing another example of an apparatus for chemical vapor deposition used in the method for producing a thin film containing silicon and phosphorus according to the present invention.

Hereinafter, the present invention will be described in detail based on preferred embodiments.
The silicon compound used for this invention is represented by the said General formula (1), and is a suitable thing as a raw material for thin film formation of the thin film manufacturing method which has vaporization processes, such as CVD method. Especially, since it can be used for ALD method, it is suitable as a raw material for forming a thin film for ALD. Moreover, it is a suitable thing as a raw material for thin film formation for obtaining the thin film whose phosphorus content is 10-20 mass%.

In the above general formula (1) of the present invention, the alkyl group having 1 to 4 carbon atoms represented by R ^{1 to} R ⁶ includes methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, Examples of the alkyl group having 1 or 2 carbon atoms represented by R ^{7 to} R ¹⁰ include a methyl group and an ethyl group.

In the general formula (1), when R ^{1 to} R ¹⁰ are used in a method for producing a thin film having a step of vaporizing a compound, those in a liquid state at normal temperature and pressure and having a large vapor pressure are preferable. When the viscosity in the liquid state is low, it is particularly preferable because transportation is easy. Specifically, when X is (X-1) and R ^{1 to} R ⁶ are methyl groups or ethyl groups, X is (X-2) and R ¹ , R ² , R ³ , R ^{When 7} and R ⁸ are a methyl group or an ethyl group, when X is (X-3) and R ¹ , R ² , R ³ , R ⁹ and R ¹⁰ are a methyl group or an ethyl group, X is When (X-4), R ¹ , R ² , R ³ are a methyl group or an ethyl group, and R ¹¹ is an isopropyl group or a tertiary butyl group, X is (X-5) and R It is preferable that ^{1 to} R ³ are a methyl group or an ethyl group because the vapor pressure is high. Among them, when X is (X-1) and R ^{1 to} R ⁶ are methyl groups, X is (X-2) and R ¹ , R ² , R ³ , R ⁷ and R ⁸ are When it is a methyl group, when X is (X-3) and R ¹ , R ² , R ³ , R ⁹ and R ¹⁰ are methyl groups, X is (X-4) and R ¹ , When R ² and R ³ are methyl groups and R ¹¹ is an isopropyl group or a tertiary butyl group, when X is (X-5) and R ^{1 to} R ³ are methyl groups, ozone and Is particularly preferred because of its good reactivity. In addition, in the case of the method of manufacturing a thin film by the MOD method without vaporization process, R ¹ to R ¹¹ may be soluble in the solvent used, the film formation reaction, etc., optionally selected.

  Preferable specific examples of the silicon compound used in the present invention include, for example, the following compound No. 1-No. 41. In the following chemical formula, “Me” represents a methyl group, “Et” represents an ethyl group, “iPr” represents an isopropyl group, and “tBu” represents a tertiary butyl group.

  In the general formula (1) of the present invention, when X is any one of (X-1) to (X-5), the reactivity with a reactive gas typified by ozone is very good, Furthermore, it can be applied as a raw material for the ALD method. In particular, when X is (X-3), it is a thin film forming raw material capable of obtaining a thin film having a phosphorus content of 10 to 20% by mass when used as a chemical vapor deposition raw material. Is particularly preferred.

  The silicon compound used for the raw material for forming a thin film of the present invention is not particularly limited by its production method, and is produced by applying a known reaction. For example, as a method for producing a compound in which X is (X-4) in the general formula (1), an intermediate obtained by reacting a corresponding trialkylsilylalkylamine with normal butyl lithium is trichloride. It is known that phosphorus can be reacted and further methylmagnesium bromide can be reacted. In the general formula (1), X is (X-1), (X-2), (X-3) or (X-5), and also described as Production Examples 1 to 3 and 5 described later, respectively. Can be manufactured by a method that has been applied or a method to which they are applied.

  The thin film forming raw material of the present invention is a thin film precursor made of the silicon compound described above, and its form varies depending on the manufacturing process to which the thin film forming raw material is applied. For example, when producing a phosphosilicate glass thin film, only the silicon compound represented by the general formula (1) described above may be used. On the other hand, when producing a thin film containing a metal other than phosphorus and silicon and / or a semimetal, the raw material for forming a thin film of the present invention includes a compound containing a metal other than silicon and / or a semimetal in addition to the silicon compound described above. Contains a compound containing a metal (hereinafter also referred to as other precursor). When the raw material for forming a thin film of the present invention contains another precursor, the content of the other precursor is preferably 0.01 with respect to 1 mol of the silicon compound represented by the general formula (1) described above. The amount is from 10 to 10 mol, more preferably from 0.1 to 5 mol. As will be described later, the thin film forming raw material of the present invention may further contain an organic solvent and / or a nucleophilic reagent.

  In the case where the thin film forming raw material of the present invention is a chemical vapor deposition raw material, the form is appropriately selected depending on the method such as the transporting and supplying method of the CVD method used.

  As the above transportation and supply method, the CVD raw material is vaporized by heating and / or decompressing in the raw material container, and the substrate is installed together with a carrier gas such as argon, nitrogen, helium or the like used as necessary. The gas transport method introduced into the film formation chamber (hereinafter also referred to as a deposition reaction section), the CVD raw material is transported to the vaporization chamber in a liquid or solution state, heated in the vaporization chamber, and / or There is a liquid transport method in which vaporization is performed by reducing the pressure and the gas is introduced into a film formation chamber. In the case of the gas transport method, the silicon compound itself represented by the general formula (1) is used as a CVD raw material, and in the case of the liquid transport method, the silicon compound itself represented by the general formula (1) or the compound is organically used. A solution dissolved in a solvent becomes a raw material for CVD.

  In the multi-component CVD method, the CVD raw material is vaporized and supplied independently for each component (hereinafter sometimes referred to as a single source method), and the multi-component raw material is mixed in advance with a desired composition. There is a method of vaporizing and supplying a mixed raw material (hereinafter, sometimes referred to as a cocktail sauce method). In the case of the cocktail source method, a mixture or mixed solution composed of the silicon compound represented by the general formula (1), or a mixture or mixed solution composed of the silicon compound and another precursor is a raw material for CVD.

  As said organic solvent, it does not receive a restriction | limiting in particular, A well-known general organic solvent can be used. Examples of the organic solvent include acetates such as ethyl acetate, butyl acetate and methoxyethyl acetate; ethers such as tetrahydrofuran, tetrahydropyran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, dibutyl ether and dioxane; Ketones such as butyl ketone, methyl isobutyl ketone, ethyl butyl ketone, dipropyl ketone, diisobutyl ketone, methyl amyl ketone, cyclohexanone, methylcyclohexanone; hexane, cyclohexane, methylcyclohexane, dimethylcyclohexane, ethylcyclohexane, heptane, octane, toluene, Hydrocarbons such as xylene; 1-cyanopropane, 1-cyanobutane, 1-cyanohexa , Hydrocarbons having a cyano group such as cyanocyclohexane, cyanobenzene, 1,3-dicyanopropane, 1,4-dicyanobutane, 1,6-dicyanohexane, 1,4-dicyanocyclohexane, 1,4-dicyanobenzene Pyridine, lutidine and the like, and these are used alone or as a mixed solvent of two or more kinds depending on the solubility of the solute, the relationship between the use temperature and boiling point, the flash point, and the like. When these organic solvents are used, the total amount of the silicon compound represented by the above general formula (1) and other precursors in the organic solvent is 0.01 to 2.0 mol / liter, particularly 0.05 to It is preferable to adjust to 1.0 mol / liter.

  In addition, in the case of a multi-component CVD method, other precursors used together with the silicon compound represented by the general formula (1) are not particularly limited, and are well-known general materials used for CVD raw materials. A precursor can be used.

  The other precursor is one or more selected from the group consisting of compounds used as organic ligands such as alcohol compounds, glycol compounds, β-diketone compounds, cyclopentadiene compounds, and organic amine compounds. And compounds with metals and / or metalloids (excluding silicon). The precursor metal or metalloid species include magnesium, calcium, strontium, barium, titanium, zirconium, hafnium, vanadium, niobium, tantalum, manganese, iron, ruthenium, cobalt, rhodium, aluminum, iridium, nickel, palladium, Platinum, copper, silver, gold, zinc, gallium, indium, germanium, tin, lead, antimony, bismuth, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, Examples include thulium and ytterbium.

  Examples of the alcohol compound used as the organic ligand of the other precursor include methanol, ethanol, propanol, isopropyl alcohol, butanol, secondary butyl alcohol, isobutyl alcohol, tertiary butyl alcohol, pentyl alcohol, isopentyl alcohol, Alkyl alcohols such as 3-pentyl alcohol; 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, 2- (2-methoxyethoxy) ethanol, 2-methoxy-1-methylethanol, 2-methoxy-1,1 -Dimethylethanol, 2-ethoxy-1,1-dimethylethanol, 2-isopropoxy-1,1-dimethylethanol, 2-butoxy-1,1-dimethylethanol, 2- (2-methoxyethoxy) -1,1 − Methylethanolamine, 2-propoxy-1,1-diethylethanolamine, 2-s-butoxy-1,1-diethyl ethanol, ether alcohols such as 3-methoxy-1,1-dimethyl propanol.

  Examples of the glycol compound include 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 2,4-hexanediol, 2,2-dimethyl-1,3-propanediol, 2,2 -Diethyl-1,3-propanediol, 1,3-butanediol, 2,4-butanediol, 2,2-diethyl-1,3-butanediol, 2-ethyl-2-butyl-1,3-propane Diol, 2,4-pentanediol, 2-methyl-1,3-propanediol, 2-methyl-2,4-pentanediol, 2,4-hexanediol, 2,4-dimethyl-2,4-pentanediol Etc.

  Examples of the β-diketone compound include acetylacetone, hexane-2,4-dione, 5-methylhexane-2,4-dione, heptane-2,4-dione, 2-methylheptane-3,5-dione, Alkyl-substituted β-diketones such as 2,6-dimethylheptane-3,5-dione; 1,1,1-trifluoropentane-2,4-dione, 1,1,1-trifluoro-5,5- Fluorine substitution such as dimethylhexane-2,4-dione, 1,1,1,5,5,5-hexafluoropentane-2,4-dione, 1,3-diperfluorohexylpropane-1,3-dione Alkyl β-diketones; 1,1,5,5-tetramethyl-1-methoxyhexane-2,4-dione, 2,2,6,6-tetramethyl-1-methoxyheptane-3,5-dione, 2, 2 6,6-tetramethyl-1 (2-methoxyethoxy) ether-substituted β- diketones such as heptane-3,5-dione, and the like.

Examples of the cyclopentadiene compound include cyclopentadiene, methylcyclopentadiene, ethylcyclopentadiene, propylcyclopentadiene, isopropylcyclopentadiene, butylcyclopentadiene, second butylcyclopentadiene, isobutylcyclopentadiene, tert-butylcyclopentadiene, dimethylcyclopentadiene. Examples thereof include pentadiene and tetramethylcyclopentadiene.
Examples of the organic amine compound include methylamine, ethylamine, propylamine, isopropylamine, butylamine, secondary butylamine, tertiary butylamine, isobutylamine, dimethylamine, diethylamine, dipropylamine, diisopropylamine, ethylmethylamine, propylmethylamine And isopropylmethylamine.

  In the case of the single source method, the other precursor is preferably a compound similar to the silicon compound used in the raw material for forming a thin film of the present invention in terms of heat and / or oxidative decomposition, and in the case of the cocktail source method. In addition to being similar in heat and / or oxidative decomposition behavior to the silicon compound used in the thin film forming raw material of the present invention, those that do not undergo alteration due to chemical reaction during mixing are preferred.

  Further, the raw material for forming a thin film of the present invention may contain a nucleophilic reagent as needed to impart stability of the silicon compound and other precursors used in the raw material for forming a thin film of the present invention. Good. Examples of the nucleophilic reagent include ethylene glycol ethers such as glyme, diglyme, triglyme and tetraglyme, 18-crown-6, dicyclohexyl-18-crown-6, 24-crown-8, dicyclohexyl-24-crown-8. , Crown ethers such as dibenzo-24-crown-8, ethylenediamine, N, N′-tetramethylethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, 1,1,4,7,7- Polyamines such as pentamethyldiethylenetriamine, 1,1,4,7,10,10-hexamethyltriethylenetetramine and triethoxytriethyleneamine, cyclic polyamines such as cyclam and cyclen, pyridine, pyrrolidine and pipette Heterocyclic compounds such as gin, morpholine, N-methylpyrrolidine, N-methylpiperidine, N-methylmorpholine, tetrahydrofuran, tetrahydropyran, 1,4-dioxane, oxazole, thiazole, oxathiolane, methyl acetoacetate, ethyl acetoacetate, Β-ketoesters such as acetoacetate-2-methoxyethyl or β-diketones such as acetylacetone, 2,4-hexanedione, 2,4-heptanedione, 3,5-heptanedione, etc., and these nucleophilic properties The reagent is used in an amount of usually 0.1 to 10 moles, preferably 1 to 4 moles per mole of the precursor.

  The raw material for forming a thin film of the present invention contains as little impurities metal elements as possible, impurities halogen such as impurity chlorine, and organic impurities as much as possible. The impurity metal element content is preferably 100 ppb or less for each element, more preferably 10 ppb or less, and the total amount is preferably 1 ppm or less, more preferably 100 ppb or less. In particular, when it is used as an LSI gate insulating film, gate film, or barrier layer, the content of alkali metal elements, alkaline earth metal elements, and related elements that affect the electrical characteristics of the resulting thin film may be reduced. is necessary. The impurity halogen content is preferably 100 ppm or less, more preferably 10 ppm or less, and still more preferably 1 ppm or less. The total amount of impurity organic components is preferably 500 ppm or less, more preferably 50 ppm or less, and still more preferably 10 ppm or less. In addition, since moisture causes particle generation in the chemical vapor deposition raw material and particle generation during thin film formation, the metal and / or metalloid compound, the organic solvent, and the nucleophilic reagent, In order to reduce each moisture, it is better to remove moisture as much as possible before use. The water content of each of the metal and / or metalloid compound, the organic solvent, and the nucleophilic reagent is preferably 10 ppm or less, and more preferably 1 ppm or less.

  Moreover, it is preferable that the raw material for forming a thin film of the present invention contains particles as little as possible in order to reduce or prevent particle contamination of the formed thin film. Specifically, in the particle measurement by the light scattering liquid particle detector in the liquid phase, the number of particles larger than 0.3 μm is preferably 100 or less in 1 ml of the liquid phase, and larger than 0.2 μm. The number of particles is more preferably 1000 or less in 1 ml of the liquid phase, and the number of particles larger than 0.2 μm is further preferably 100 or less in 1 ml of the liquid phase.

  The thin film production method of the present invention for producing a thin film using the thin film forming raw material of the present invention includes any of the silicon compound represented by the general formula (1) and other precursors used as necessary A vapor obtained by vaporizing components and a reactive gas used as necessary are introduced into a film forming chamber in which the substrate is installed, and then the precursor is decomposed and / or chemically reacted on the substrate to form a thin film on the substrate. This is based on the CVD method for growing and depositing on the surface. There are no particular restrictions on the method of transporting and supplying the raw material, the deposition method, the production conditions, the production apparatus, etc., and well-known general conditions and methods can be used.

  Examples of the reactive gas used as necessary include oxygen, ozone, nitrogen dioxide, nitric oxide, water vapor, hydrogen peroxide, formic acid, acetic acid, acetic anhydride, etc. Examples of reducing substances include hydrogen, and examples of nitrides that can be used include organic amine compounds such as monoalkylamines, dialkylamines, trialkylamines, and alkylenediamines, hydrazine, and ammonia. Can be used alone or in combination of two or more. Especially, the reactivity with ozone is especially favorable for the raw material for thin film formation of this invention.

  Examples of the transport and supply method include the gas transport method, the liquid transport method, the single source method, and the cocktail sauce method described above.

  In addition, the above deposition methods include thermal CVD in which a raw material gas or a raw material gas and a reactive gas are reacted only by heat to deposit a thin film, plasma CVD using heat and plasma, photo CVD using heat and light, heat In addition, optical plasma CVD using light and plasma, and ALD in which the deposition reaction of CVD is divided into elementary processes and deposition is performed stepwise at the molecular level.

Moreover, as said manufacturing conditions, reaction temperature (base | substrate temperature), reaction pressure, a deposition rate, etc. are mentioned. About reaction temperature, 100 degreeC or more which is the temperature with which the raw material for thin film formation etc. of this invention fully reacts is preferable, and 150 to 400 degreeC is more preferable. The reaction pressure is preferably atmospheric pressure to 10 Pa in the case of thermal CVD or photo CVD, and preferably 2000 Pa to 10 Pa in the case of using plasma.
The deposition rate can be controlled by the raw material supply conditions (vaporization temperature, vaporization pressure), reaction temperature, and reaction pressure. When the deposition rate is large, the properties of the obtained thin film may be deteriorated. When the deposition rate is small, a problem may be caused in productivity. Therefore, 0.01 to 100 nm / min is preferable, and 1 to 50 nm / min is more preferable. In the case of the ALD method, the number of cycles is controlled so as to obtain a desired film thickness.

  For example, when the phosphosilicate thin film is formed by the ALD method, the precursor thin film is formed on the substrate surface by the thin film forming raw material of the present invention introduced into the deposition reaction section after the raw material introducing step described above. (Precursor thin film forming step). At this time, heat may be applied by heating the substrate or heating the deposition reaction part. The precursor thin film formed in this step is a phosphosilicate thin film or a thin film formed by decomposition and / or reaction of a part of the thin film forming raw material of the present invention, and is different from the target phosphosilicate thin film. Having a composition. The substrate temperature when this step is performed is preferably room temperature to 500 ° C.

  Next, the raw material gas for forming a thin film and by-produced gas of the present invention are exhausted from the deposition reaction part (exhaust process). Although it is ideal that the unreacted raw material gas for forming a thin film and the by-product gas of the present invention are completely exhausted from the deposition reaction part, it is not necessarily exhausted completely. Examples of the exhaust method include a method of purging the system with an inert gas such as nitrogen, helium, and argon, a method of exhausting the system by depressurizing the system, a method combining these, and the like. When the pressure is reduced, the degree of pressure reduction is preferably 0.01 to 300 Pa, and more preferably 0.01 to 100 Pa.

  Next, an oxidizing gas is introduced into the deposition reaction portion, and a phosphorous silicate thin film is formed from the precursor thin film obtained in the previous precursor thin film forming step by the action of the oxidizing gas or the oxidizing gas and heat ( Phosphorous silicate thin film forming step). The temperature when heat is applied in this step is preferably room temperature to 500 ° C, more preferably 150 to 450 ° C. The raw material for forming a thin film of the present invention has good reactivity with an oxidizing gas typified by ozone, and can efficiently obtain a phosphosilicate thin film.

  In the thin film manufacturing method of the present invention, when the ALD method is employed as described above, the thin film deposition is performed by a series of operations including the raw material introduction step, the precursor thin film formation step, the exhaust step, and the phosphosilicate thin film formation step. May be repeated one or more times until a thin film having a required film thickness is obtained. In this case, after one cycle is performed, the unreacted raw material gas for forming a thin film and the oxidizing gas of the present invention and the by-produced gas are exhausted from the deposition reaction portion in the same manner as in the exhausting step. A cycle is preferred.

  In the formation of the phosphosilicate thin film by the ALD method, energy such as plasma, light, or voltage may be applied. The timing for applying these energies is not particularly limited. For example, when introducing the raw material gas for forming a thin film of the present invention in the raw material introducing step, heating in the precursor thin film forming step or the phosphosilicate thin film forming step, exhausting It may be at the time of exhausting the system in the process, at the time of introducing the oxidizing gas in the phosphosilicate thin film forming process, or between the above processes.

  In the method for producing a thin film of the present invention, after thin film deposition, annealing may be performed in an inert atmosphere, an oxidizing atmosphere, or a reducing atmosphere in order to obtain better electrical characteristics. When embedding is necessary, a reflow process may be provided. The temperature in this case is usually 200 to 1000 ° C, preferably 250 to 500 ° C.

  As an apparatus for producing a thin film using the raw material for forming a thin film of the present invention, a known chemical vapor deposition apparatus can be used. Specific examples of the apparatus include an apparatus capable of carrying a precursor as shown in FIG. 1 by bubbling supply, an apparatus having a vaporization chamber as shown in FIG. 2, and a reactive gas as shown in FIG. 3 or FIG. And an apparatus capable of performing plasma treatment. In addition, the present invention is not limited to the single wafer type apparatus as shown in FIGS. 1, 2, 3 and 4, and an apparatus capable of simultaneously processing a large number of sheets using a batch furnace can also be used.

  A thin film manufactured using the raw material for forming a thin film of the present invention can be selected from other precursors, reactive gases, and manufacturing conditions as appropriate, so that a desired type of metal, oxide ceramics, nitride ceramics, glass, etc. It can be a thin film. Examples of the composition of the thin film to be manufactured include a silicon thin film containing phosphorus. Among these, a phosphosilicate glass thin film is particularly preferably produced. The phosphosilicate glass thin film is used as a surface stabilizing film, an interlayer insulating film, and a wiring protective film for electronic materials.

  Hereinafter, the present invention will be described in more detail with reference to production examples, examples and evaluation examples. However, the present invention is not limited by the following examples.

[Production Example 1] Compound No. 1 1 (Compound wherein X is (X-1) in general formula (1)) In an argon gas atmosphere, diethyl ether 73. dehydrated with 16.1 g of hexamethyldisilazane in a 500 mL four-necked reaction flask. 6 g was charged and cooled with dry ice. There, it was made to react, dripping 43.8g of hexane solutions of normal butyl lithium (1.6 mol / L). After completion of the dropwise addition, the reaction was continued for about 2 hours after returning to room temperature. Subsequently, the reaction flask was again cooled to −70 ° C. with dry ice and isopropanol, and 13.6 g of phosphorus trichloride was dropped into the white suspension for reaction. When the temperature is raised to 0 ° C., the reaction solution changes from a yellow suspension to a light yellow, white suspension. After the reaction is continued at 0 ° C. for 1 hour, methyl magnesium bromide (3 mol / L 68.1 g of a diethyl ether solution was added dropwise and reacted. After completion of the dropwise addition, the mixture was stirred at 0 ° C. for 2 hours, and further stirred at room temperature for 1 hour. Filtration was performed through a 0.5 μm membrane filter, and diethyl ether and hexane were removed from the obtained filtrate to obtain a liquid residue. The liquid residue was distilled at a bath temperature of 75 ° C. under a reduced pressure of 3.5 Torr to obtain a compound distilled at a tower top temperature of 44 ° C. The recovery by this purification was 54%. The obtained compound was a colorless transparent liquid at normal temperature and normal pressure (25 ° C., 1 atm, the same applies hereinafter). As a result of elemental analysis and ¹ H-NMR analysis, the resulting compound was identified as Compound No. 1 was identified. The results of these analyzes are shown below. The results of TG-DTA are also shown below.

(Analysis value)
(1) Elemental analysis (metal analysis: ICP-AES)
Si: 25.0 mass%, P: 13.8 mass%, C: 43.7 mass%, H: 11.1 mass%, N: 6.24 mass% (theoretical value; Si: 25.37 mass%) P: 13.99% by mass, C: 43.39% by mass, H: 10.92% by mass, N: 6.33% by mass)
(2) ¹ H-NMR (solvent: heavy benzene) (chemical shift: multiplicity: H number)
(0.259 ppm: s: 18.1) (1.21 ppm: d: 6.0)
(3) TG-DTA
TG-DTA (Ar 100 ml / min, 10 ° C./min temperature increase, sample amount 8.903 mg) 50% by mass reduction temperature 122 ° C.

[Production Example 2] Compound No. 5 (Compound wherein X is (X-2) in general formula (1)) Under argon gas atmosphere, 5.45 g of magnesium metal and 221.14 g of dehydrated tetrahydrofuran were charged into a 500 mL four-necked reaction flask. The Grignard solution was prepared while heating in a 45 ° C. bath and adding 25.0 g of chloromethyltrimethylsilane dropwise. After the reaction was completed, the reaction flask was again cooled to −5 ° C. with dry ice, and 32.3 g of chlorobis (dimethylamino) phosphine was added dropwise for reaction. The reaction solution became a gray suspension, and the reaction was continued at room temperature for about 2 hours. Subsequently, filtration was performed with a 0.5 μm membrane filter, and hexane and tetrahydrofuran were removed from the obtained filtrate to obtain a liquid residue. The liquid residue was distilled at a bath temperature of 95 ° C. under a reduced pressure of 4 Torr to obtain a compound distilled at a tower top temperature of 56 ° C. The recovery by this purification was 51%. The obtained compound was a colorless and transparent liquid at normal temperature and pressure. As a result of elemental analysis and ¹ H-NMR analysis, the resulting compound was identified as Compound No. 5 was identified. The results of these analyzes are shown below. The results of TG-DTA are also shown below.

(Analysis value)
(1) Elemental analysis (metal analysis: ICP-AES)
Si: 13.6 mass%, P: 14.8 mass%, C: 46.6 mass%, H: 11.0 mass%, N: 14.1 mass% (theoretical value; Si: 13.61 mass%) , P: 15.01 mass%, C: 46.57 mass%, H: 11.23 mass%, N: 13.58 mass%)
(2) ¹ H-NMR (solvent: heavy benzene) (chemical shift: multiplicity: H number)
(0.145 ppm: d: 9.0) (0.919 ppm: d: 2.1) (2.54 ppm: d: 12.3)
(3) TG-DTA
TG-DTA (Ar 100 ml / min, 10 ° C./min temperature increase, sample amount 8.733 mg) 50 mass% reduction temperature 125 ° C.

[Production Example 3] Compound No. 18 (Compound wherein X is (X-3) in general formula (1)) Under an argon gas atmosphere, 16.3 g of tris (dimethylamino) phosphine was charged into a 100 mL four-necked reaction flask, and trimethylsilyl azide 11. 5 g was reacted dropwise with heating to 55 ° C. in the bath. Reaction occurred while generating N ₂ gas. After the reaction was completed, the compound was distilled as it was under a reduced pressure of 1 Torr at a bath of 115 ° C. to obtain a compound distilled at a tower top temperature of 53 ° C. The recovery by this purification was 51%. The obtained compound was a colorless and transparent liquid at normal temperature and pressure. As a result of elemental analysis and ¹ H-NMR analysis, the resulting compound was identified as Compound No. 18 was identified. The results of these analyzes are shown below. The results of TG-DTA are also shown below.

(Analysis value)
(1) Elemental analysis (metal analysis: ICP-AES)
Si: 11.1% by mass, P: 12.5% by mass, C: 43.0% by mass, H: 10.9% by mass, N: 24.1% by mass (theoretical value; Si: 11.22% by mass) P: 12.37% by mass, C: 43.17% by mass, H: 10.87% by mass, N: 22.38% by mass)
(2) ¹ H-NMR (solvent: heavy benzene) (chemical shift: multiplicity: H number)
(0.404 ppm: s: 9.0) (2.38 ppm: d: 18.3)
(3) TG-DTA
TG-DTA (Ar 100 ml / min, 10 ° C./min temperature increase, sample amount 9.696 mg) 50% by mass reduction temperature 145 ° C.

[Production Example 4] Compound No. 31 (Compound wherein X is (X-4) in General Formula (1)) Under an argon gas atmosphere, hexane dehydrated with 30.1 g of trimethylsilyl-t-butylamine in a 1 L four-necked reaction flask 78 g was charged, and 88.77 g of a hexane solution of normal butyl lithium (1.6 mol / L) was added dropwise at 0 ° C. while cooling with dry ice to cause a reaction. After reacting at room temperature, it cooled to -70 degreeC with dry ice and isopropanol, and 28.4 g of phosphorus trichloride was dripped and made it react. The reaction solution turned from a pale yellow suspension to a yellow suspension. The mixture was cooled to 0 ° C. with ice water and reacted for about 2 hours. After cooling again with dry ice and isopropanol, 410.5 g of a tetrahydrofuran solution of methylmagnesium bromide (1 mol / L) was added dropwise at -5 ° C. for reaction. After completion of the dropwise addition, the reaction was continued at 0 ° C. for 2 hours, and further continued at room temperature for about 2 hours. Subsequently, filtration was performed with a 0.5 μm membrane filter, and hexane and tetrahydrofuran were removed from the obtained filtrate to obtain a liquid residue. The liquid residue was distilled at a bath of 90 ° C. under a reduced pressure of 3 Torr to obtain a compound distilled at a tower top temperature of 48 ° C. The recovery by this purification was 51%. The obtained compound was a colorless and transparent liquid at normal temperature and pressure. As a result of elemental analysis and ¹ H-NMR analysis, the resulting compound was identified as Compound No. 31 was identified. The results of these analyzes are shown below. The results of TG-DTA are also shown below.

(Analysis value)
(1) Elemental analysis (metal analysis: ICP-AES)
Si: 13.4 mass%, P: 14.75 mass%, C: 52.8 mass%, H: 11.8 mass%, N: 7.0 mass% (theoretical value; Si: 13.68 mass%) , P: 15.08 mass%, C: 52.64 mass%, H: 11.78 mass%, N: 6.82 mass%)
(2) ¹ H-NMR (solvent: heavy benzene) (chemical shift: multiplicity: H number)
(0.319 ppm: s: 9.0) (1.27 ppm: s: 6.07) (1.29 ppm: d: 9.1)
(3) TG-DTA
TG-DTA (Ar 100 ml / min, 10 ° C./min temperature increase, sample amount 9.799 mg) 50% by mass reduction temperature 126 ° C.

[Production Example 5] Compound No. 38 (Compound wherein X is (X-5) in General Formula (1)) Under argon gas atmosphere, 50.3 g of a toluene solution of trimethylphosphine (1 mol / L) was placed in a 200 mL four-necked reaction flask. Then, 6.84 g of trimethylsilyl azide was added dropwise and reacted at 50 ° C. for 8.5 hours, then gradually heated from 60 ° C. and refluxed at 106 ° C. for 2 hours while generating N ₂ gas. After completion of the reaction, the reaction mixture was directly concentrated in a bath at 145 ° C. under normal pressure, and then a compound distilled at a tower top temperature of 45 ° C. in a bath at 75 ° C. under reduced pressure was obtained. The recovery by this purification was 49%. The obtained compound was a colorless and transparent liquid at normal temperature and pressure. As a result of elemental analysis and ¹ H-NMR analysis, the resulting compound was identified as Compound No. 38. The results of these analyzes are shown below. The results of TG-DTA are also shown below.

(Analysis value)
(1) Elemental analysis (metal analysis: ICP-AES)
Si: 16.9% by mass, P: 18.70% by mass, C: 44.1% by mass, H: 11.6% by mass, N: 8.9% by mass (theoretical value; Si: 17.20% by mass) , P: 18.97 mass%, C: 44.14 mass%, H: 11.11 mass%, N: 8.58 mass%)
(2) ¹ H-NMR (solvent: heavy benzene) (chemical shift: multiplicity: H number) (0.338 ppm: s: 0.96) (0.845 ppm: d: 1.0)
(3) TG-DTA (Ar 100 ml / min, 10 ° C./min temperature increase, sample amount 9.141 mg) 50 mass% reduction temperature 102 ° C.

[Evaluation Example 1] Evaluation of thermal stability of silicon compound used for thin film forming raw material of the present invention For 1, 5, 18 and 38 and Comparative Compounds 1 and 2 shown below, the thermal stability of each compound was confirmed by measuring the temperature at which an exothermic peak was observed using a DSC measuring device as the pyrolysis temperature. did. The results are shown in Table 1. When the thermal stability of the thin film forming raw material is high, the film can be formed at a higher temperature. The fact that the film can be formed at a higher temperature can reduce impurities such as carbon residues in the obtained thin film. Therefore, the thermal stability of the raw material for forming a thin film affects the quality of the obtained thin film.

  From the results of Table 1, when Comparative Examples 1-1 to 1-4 and Comparative Evaluation Example 1 and Comparative Evaluation Example 2 are compared, the compound Nos. Used in Evaluation Examples 1-1 to 1-4, respectively. 1, 5, 18 and 38 were found to have higher thermal stability than Comparative Compounds 1 and 2 used in Comparative Evaluation Example 1 and Comparative Evaluation Example 2, respectively. Among these, compound No. No. 18 has a thermal stability of 500 ° C. or higher and was found to be very suitable as a raw material for forming a thin film.

[Evaluation Example 2] Reactivity Evaluation of Silicon Compound and Reactive Gas Compound No. 2 which is a silicon compound used as a raw material for forming a thin film of the present invention. 1, 5, 18, 31, and 38 and Comparative Compound 2 were measured for TG-DTA in an ozone atmosphere, and the presence or absence of an exothermic peak due to an oxidation reaction between each compound and ozone was confirmed. The measurement conditions were a mixed gas of O ₃ and O ₂ (mixing ratio: O ₃ 4%, O ₂ 96%) 2000 ml / min, 10 ° C./min temperature rise, and a sample amount of about 10 mg. The results are shown in Table 2.

  According to Table 2, it was found from the results of Comparative Evaluation Example 3 that Comparative Compound 2 did not react with ozone. Further, from the results of Comparative Evaluation Example 3 and Evaluation Examples 2-1 to 2-5, Compound No. 1 which is a silicon compound used for the raw material for forming a thin film of the present invention was used. 1, 5, 18, 31 and 38 were found to react well with ozone.

[Example 1] Production of phosphosilicate glass thin film by ALD method 1, 5, 18, 31, and 38 are used as chemical vapor deposition raw materials, and each compound is used to form a phosphosilicate glass on a silicon wafer as a substrate by an ALD method using the apparatus shown in FIG. A thin film was produced. About the obtained thin film, when the film thickness measurement by X-ray reflectivity method and the thin film structure and thin film composition were confirmed by X-ray photoelectron spectroscopy, all the obtained thin films were phosphosilicate glass thin films. The film thickness obtained per cycle was 0.01 to 0.1 nm.
(conditions)
Reaction temperature (substrate temperature): 300 to 400 ° C., reactive gas: ozone gas (process)
A series of steps consisting of the following (1) to (4) was set as one cycle and repeated 50 cycles.
(1) Raw material container temperature: The vapor of the chemical vapor deposition raw material vaporized under the conditions of 23 ° C. and the raw material container pressure of 100 Pa is introduced and deposited at a system pressure of 100 Pa for 10 seconds.
(2) The unreacted raw material is removed by argon purge for 15 seconds.
(3) A reactive gas is introduced and reacted at a system pressure of 100 Pa for 10 seconds.
(4) Unreacted raw materials are removed by argon purge for 15 seconds.

[Comparative Example 1] Production of a phosphosilicate glass thin film by the ALD method Using the comparative compound 2 as a raw material for chemical vapor deposition, a phosphosilicate glass thin film is produced on a silicon wafer by the ALD method under the same conditions as in Example 1. An attempt was made but a thin film could not be obtained.

  In Example 1, a phosphosilicate glass thin film could be obtained by ALD method for all raw materials of the present invention, whereas in Comparative Example 1, a thin film could not be obtained. Therefore, since the raw material for forming a thin film of the present invention can be applied to an ALD process, it was found that the raw material for forming a thin film was excellent as a raw material for chemical vapor deposition.

[Example 2] Production of phosphosilicate glass thin film by CVD method A phosphosilicate glass thin film was produced on a silicon wafer substrate by a thermal CVD method using the apparatus shown in FIG. About the obtained thin film, when the film thickness measurement by X-ray reflectivity method and the thin film structure and thin film composition were confirmed by X-ray photoelectron spectroscopy, the obtained thin film was a phosphosilicate glass thin film. The film thickness was 30 nm, and the phosphorus content in the obtained thin film was 12% by mass.
(Conditions) Raw material container temperature: 23 ° C., reaction system pressure: 100 Pa, reaction time: 120 minutes, substrate temperature: 300 ° C., carrier gas (Ar): 150 ml / min, reactive gas: ozone gas

Comparative Example 2 Production of Phosphosilicate Glass Thin Film by CVD Method Using Comparative Compound 2 as a raw material for chemical vapor deposition and using the apparatus shown in FIG. A glass thin film was produced. About the obtained thin film, when the film thickness measurement by X-ray reflectivity method and the thin film structure and thin film composition were confirmed by X-ray photoelectron spectroscopy, the obtained thin film was a phosphosilicate glass thin film. The film thickness was 100 nm, and the phosphorus content in the obtained thin film was 5% by mass.
(Conditions) Raw material container temperature: 23 ° C., reaction system pressure: 100 Pa, reaction time: 240 minutes, substrate temperature: 260 ° C., carrier gas (Ar): 150 ml / min, reactive gas: ozone gas

  Since the thin film obtained by Comparative Example 2 had a phosphorus content of 5% by mass, in order to obtain a phosphosilicate glass thin film having a phosphorus content of 10 to 20% by mass using Comparative Compound 1, a comparative compound was used. It has been found that it is necessary to add a phosphorus donor other than 1. On the other hand, since the phosphorus content of the thin film obtained in Example 2 was 12% by mass, 18 is a chemical vapor deposition raw material. It was found that this was a chemical vapor deposition raw material capable of producing a phosphosilicate glass thin film having a phosphorus content of 10 to 20% by mass without adding another phosphorus supplier separately from 18.

Claims (2)

A thin film forming raw material comprising a silicon compound represented by the following general formula (1).

(In the formula, R ^{1 to} R ³ each independently represents an alkyl group having 1 to 4 carbon atoms, and X represents a group represented by any one of the following (X-1) to (X-5).)

(Wherein R ^{4 to} R ⁶ each independently represents an alkyl group having 1 to 4 carbon atoms, R ^{7 to} R ¹⁰ each independently represents an alkyl group having 1 or 2 carbon atoms, and R ¹¹ represents an isopropyl group or Represents a tertiary butyl group.)
  The vapor containing the silicon compound obtained by vaporizing the raw material for forming a thin film according to claim 1 is introduced into a film forming chamber in which a substrate is installed, and the silicon compound is decomposed and / or chemically reacted. A method for producing a thin film, wherein a thin film containing silicon and phosphorus is formed on the surface of the substrate.

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