JP6016558B2 - Method for producing silica-based coating - Google Patents

Description

  The present invention relates to a method for producing a silica film using an organosilane condensation reaction product.

  A solution of a silicon compound mainly composed of an organosilane condensation product (hereinafter referred to as organic SOG in accordance with common usage in the semiconductor field) is well known as a material for forming an insulating film for a semiconductor device. Things are commercially available. A typical application is to fill a gap generated between aluminum wirings that have been used for a long time in semiconductor devices. Organic SOG is used for this purpose because an insulating film can be easily formed by baking after applying the solution, and it can be filled in a relatively narrow space because it is used in the form of a solution. This is because of this. As mentioned above, this material is suitable for filling narrow voids, and also has the advantage of low water absorption and low dielectric constant, so it does not only play an auxiliary role of void filling. Also proposed as an interlayer insulating film between wirings (for example, Patent Document 1). Thus, organic SOG has several manufacturing advantages and is used in industry.

JP 2002-334873 A

However, since organic SOG is mainly composed of an organosilane condensation product, it deteriorates over time, and the film thickness of the film formed using organic SOG varies depending on the state of the organic SOG. However, there was room for improvement from the viewpoint of suppressing this.
Accordingly, an object of the present invention is to reduce film thickness variation caused by alteration of organic SOG in a film formed using organic SOG.

  As a result of intensive studies to develop a method for achieving the above-mentioned object, the present inventors have found that the following method for producing a silica-based coating solves the above-mentioned problems and completed the present invention. That is, the present invention is as follows.

[1] A coating layer forming step in which a coating solution containing an organosilane condensation reaction product is coated on a substrate to form a coating layer;
A pre-curing step in which the condensation reaction in the coating layer further proceeds by heating the coating layer at a temperature of 30 ° C. or more and less than 100 ° C. in an inert atmosphere;
After the preliminary curing step, a fired silica-based film forming step of forming a fired silica-based film by heating the coating layer at a temperature of 400 ° C. or higher and 800 ° C. or lower;
A method for producing a silica-based coating, comprising:
[2] The method for producing a silica-based film according to [1], wherein the organosilane contains tetraethoxysilane.
[3] The method for producing a silica-based coating according to the above [1] or [2], wherein the coating solution contains silica particles.

  According to the present invention, since the film thickness variation of the film due to the change of organic SOG with time can be suppressed, a silica-based film with a uniform film thickness can be formed.

  Hereinafter, modes for carrying out the present invention (hereinafter abbreviated as “embodiments”) will be described in detail. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary.

  In the present embodiment, a coating layer forming step of forming a coating layer by coating a coating solution containing a condensation reaction product of organosilane on a substrate, and the coating layer at 30 ° C. or more and less than 100 ° C. in an inert atmosphere A pre-curing step in which the condensation reaction in the coating layer further proceeds by heating at a temperature; and after the pre-curing step, the coating layer is heated at a temperature of 400 ° C. to 800 ° C. A method for producing a silica-based coating, comprising:

  Conventionally, due to the change in quality of this organosilane condensation product over time, one of the issues that arises in the production of coatings on semiconductor devices that are intended for use is the film thickness that occurs when coatings are manufactured under the same conditions. Change. Especially in the mass production of semiconductor devices, after setting the organic SOG in the coating device, the coating solution continues to be installed in a room temperature environment where transformation is likely to proceed. The film thickness changes greatly in a short period of time, and as a result, there is a possibility that it is out of production standards. In this Embodiment, the said subject is solved by heating the coating liquid containing the condensation reaction material of organosilane on specific conditions.

  The coating solution is typically obtained by dissolving an organosilane condensation reaction product in an appropriate solvent.

  Examples of the organosilane include tetrafunctional silanes such as tetramethoxysilane and tetraethoxysilane, trifunctional or bifunctional alkoxysilanes such as methyltrimethoxysilane, methyltriethoxysilane, dimethyltrimethoxysilane, and dimethyltriethoxysilane, and Hydrogenated alkoxysilanes such as trimethoxysilane and triethoxysilane can be used alone or as a mixture of two or more. Especially, it is preferable that organosilane contains tetrafunctional organosilane by the point that the homogeneity of a coating layer is favorable, and it is more preferable that tetraethoxysilane is included as the tetrafunctional organosilane.

  The organosilane condensation reaction product can be produced, for example, by a method of polycondensing the above-described organosilane in the presence of water. At this time, polycondensation is performed in the presence of water in an acid atmosphere in the range of preferably 0.1 equivalents or more and 10 equivalents or less, more preferably 0.4 equivalents or more and 8 equivalents or less with respect to the number of functional groups of the organosilane. I do. When the amount of water is within the above range, it is preferable because the pot life of the condensation reaction product can be increased and the crack resistance after film formation can be improved.

  Further, an acid catalyst may be added during the condensation. Examples of the acid catalyst include inorganic acids and organic acids. Examples of the inorganic acid include hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid, phosphoric acid, and boric acid. Examples of the organic acid include acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, oxalic acid, maleic acid, methylmalonic acid, benzoic acid, and p-aminobenzoic acid. Examples include acid, p-toluenesulfonic acid, benzenesulfonic acid, trifluoroacetic acid, formic acid, malonic acid, sulfonic acid, phthalic acid, fumaric acid, citric acid, tartaric acid, citraconic acid, malic acid, glutaric acid and the like.

  Said inorganic acid and organic acid can be used 1 type or in mixture of 2 or more types. The amount of the acid catalyst used is an amount that adjusts the pH of the reaction system in the production of the organosilane condensation product to a range of 0.01 to 7.0, preferably 5.0 to 7.0. Preferably there is. In this case, the weight average molecular weight of the organosilane condensation reaction product can be well controlled.

  The condensation product of organosilane can be produced in an organic solvent or a mixed solvent of water and an organic solvent. Examples of the organic solvent include alcohols, esters, ketones, ethers, aliphatic hydrocarbon compounds, aromatic hydrocarbon compounds, amide compounds, and the like.

  Examples of the alcohols include: monohydric alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, and butyl alcohol; polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, glycerin, trimethylolpropane, and hexanetriol; ethylene glycol monomethyl Ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene Glycol monopropyl ether, mono ethers of polyhydric alcohols such as propylene glycol monobutyl ether; and the like.

  Examples of the esters include methyl acetate, ethyl acetate, butyl acetate and the like. Examples of the ketones include acetone, methyl ethyl ketone, and methyl isoamyl ketone.

  As the ethers, in addition to the monoethers of the above polyhydric alcohols, for example: ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, ethylene glycol dibutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, Polyhydric alcohol ethers obtained by alkyl etherifying all hydroxyl groups of polyhydric alcohols such as propylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, and diethylene glycol diethyl ether; tetrahydrofuran, 1,4-dioxane, anisole and the like.

  Examples of the aliphatic hydrocarbon compounds include hexane, heptane, octane, nonane and decane.

  Examples of the aromatic hydrocarbon compounds include benzene, toluene, xylene and the like.

  Examples of the amide compounds include dimethylformamide, dimethylacetamide, N-methylpyrrolidone and the like.

  Among these solvents, methanol, ethanol, isopropanol, butanol, etc. as alcohols; acetone, methyl ethyl ketone, methyl isobutyl ketone, etc. as ketones; ethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol mono as ethers Ethyl ether and the like; and amide compounds such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone and the like are preferable in terms of easy mixing with water and easy dispersion of silica particles.

  In a preferred embodiment, the condensation product of organosilane can be produced by hydrolytic condensation in an aqueous alcohol solution under weakly acidic conditions of pH 5 or more and less than 7.

These solvents may be used alone or in combination of a plurality of solvents. Moreover, you may react in a bulk, without using the said solvent.

  The reaction temperature for producing the organosilane condensation product is not particularly limited, but it is preferably -50 ° C or higher and 200 ° C or lower, more preferably 0 ° C or higher and 150 ° C or lower. By carrying out the reaction in the above temperature range, the molecular weight of the organosilane condensation reaction product can be easily controlled.

  In the coating solution, the ratio of the condensation conversion amount of the organosilane condensation reaction product to the total conversion amount of 100 mass% of the condensation reaction amount of the organosilane condensation reaction product and silica particles described later is 40% by mass or more and 99% by mass or less. It is preferable that In the present specification, the condensation conversion amount of the organosilane condensation reaction product means an amount obtained by replacing the functional group remaining in the organosilane condensation reaction product with 1/2 oxygen atom. The condensation conversion amount is preferably 40% by mass or more from the viewpoint of good film formability. The condensation conversion amount is more preferably 50% by mass or more, and still more preferably 55% by mass or more. On the other hand, it is preferable that the amount in terms of condensation is 99% by mass or less because a low shrinkage rate and good crack resistance can be obtained. The condensation conversion amount is more preferably 90% by mass or less, and still more preferably 85% by mass or less.

  Moreover, it is preferable that a coating liquid contains a silica particle from a viewpoint from which the crack tolerance of a silica type coating becomes favorable. Examples of the silica particles include fumed silica and colloidal silica. Examples of silica particles that are commercially available include LEVASIL series (manufactured by HC Starck Co., Ltd.), methanol silica sol IPA-ST, same MEK-ST, same NBA-ST, same XBA-ST, same DMAC- ST, ST-UP, ST-OUP, ST-20, ST-40, ST-C, ST-N, ST-O, ST-50, ST-OL (and above, Nissan) Chemical Industry Co., Ltd.), Quateron P L Series (manufactured by Fuso Chemical Co., Ltd.), etc .; As powdered silica particles, for example, Aerosil 130, 300, 380, TT600, OX50 (above, Nippon Aerosil) ), Sildex H31, H32, H51, H52, H121, H122 (above, manufactured by Asahi Glass Co., Ltd.), E220A, E220 (above, Japan) This silica industry Co., Ltd.), SYLYSIA470 (made by Fuji Silysia Co., Ltd.), SG flake (made by Nippon Sheet Glass Co., Ltd.), etc. can be mentioned. The silica particles can be mixed with or condensed with organosilane condensation reactants, or a combination thereof.

  The average primary particle diameter of the silica particles is preferably 1 nm or more and 120 nm or less, more preferably 40 nm or less, still more preferably 20 nm or less, and most preferably 15 nm or less. When the average primary particle size is 1 nm or more, the crack resistance is good, and when it is 120 nm or less, the homogeneity of the coating layer is good.

  The average secondary particle diameter of the silica particles is preferably 2 nm or more and 250 nm or less, more preferably 80 nm or less, still more preferably 40 nm or less, and most preferably 30 nm or less. When the average secondary particle diameter is 2 nm or more, the crack resistance is good, and when it is 250 nm or less, the homogeneity of the coating layer is good.

  The average primary particle diameter is a value obtained by calculation from the specific surface area of BET, and the average secondary particle diameter is a value measured with a dynamic light scattering photometer.

  The content of silica particles is preferably 1% by mass or more and 60% by mass or less, more preferably 10% by mass or more and 50% by mass or less with respect to 100% by mass in total of the condensation conversion amount of the condensation reaction product of organosilane and the silica particles. It is 15 mass% or less, More preferably, it is 15 mass% or less and 45 mass% or less. When the content is 1% by mass or more, the crack resistance of the silica-based film is good, and when the content is 60% by mass or less, the formability of the coating layer is good.

  The coating solution usually contains a solvent. As the solvent, various solvents capable of dissolving the organosilane condensation reaction product can be used. The solvent may be one type or a combination of two or more types. The solvent typically has a boiling point of 80 ° C. or higher from the viewpoint of suppressing solvent volatilization during preliminary curing. Here, the boiling point means the single boiling point of each of the two or more combined solvents. The boiling point is preferably 80 ° C. or higher, more preferably 90 ° C. or higher, and still more preferably 100 ° C. or higher, from the viewpoint of favorably progressing the condensation reaction in the preliminary curing step. The boiling point is preferably 220 ° C. or lower, more preferably 210 ° C. or lower, and further preferably 200 ° C. or lower, from the viewpoint that the solvent needs to be volatilized to some extent in the preliminary curing step. Preferred solvents include alcohol solvents such as butanol, pentanol, hexanol, methoxyethanol, ethoxyethanol, propylene glycol monomethyl ether, propylene glycol monomethyl ether, methyl isobutyl ketone, isoamyl methyl ketone, ethyl hexyl ketone, cyclopentanone, cyclohexanone. Ketone solvents such as butyl acetate, pentyl acetate, hexyl acetate, propyl propionate, butyl propionate, pentyl propionate, hexyl propionate, propylene glycol monomethyl ether acetate, ethyl lactate, etc. Butyl ether, anisole, ethylene glycol diethyl ether, propylene glycol dimethyl ether, propylene glycol Monomethyl ether, ether solvents such as propylene glycol diethyl ether, toluene, a hydrocarbon solvent such as xylene and the like. The amount of the solvent is preferably 100 parts by mass or more, more preferably 125 parts from the viewpoint that the pot life of the coating solution is good with respect to 100 parts by mass in total of the condensation product of organosilane and silica particles (when included). From the viewpoint that the uniformity of the coating layer is good, it is preferably 1900 parts by weight or less, more preferably 1400 parts by weight or less, and further preferably 900 parts by weight or less. Can be.

  The coating liquid may contain additional components other than the components described above. Examples of the additional component include a silane compound such as the above organosilane. From the viewpoint of good crack resistance, the content of the silane compound is preferably 40% by mass or less, more preferably 30% by mass, with respect to 100 parts by mass of the condensation conversion amount of the condensation reaction product of organosilane. % Or less, more preferably 20% by mass or less. In the present disclosure, the condensation conversion amount of the silane compound means an amount obtained by replacing the functional group in the silane compound with 1/2 oxygen atom.

  The specific process of the manufacturing method of a silica-type film is demonstrated.

  In the coating layer forming step, the coating liquid described above can be coated on the substrate by a usual method. Examples of the substrate include a silicon substrate. The substrate may have a processed structure such as a trench structure. As a coating method, for example, any known coating method such as spin coating, spray coating, or roll coating can be used. In particular, in the case of a semiconductor device, spin coating is preferable from the viewpoint of good film thickness uniformity of the coating layer. The coating conditions may be appropriately selected according to the desired film thickness for the silica-based film produced according to the present invention.

  Next, a pre-curing process that is performed after the coating liquid is applied on the substrate will be described. Pre-curing in this step is performed, for example, with a hot plate, oven, furnace, or the like. In the present invention, by pre-curing at a specific temperature, the effect of suppressing the film thickness variation of the coating due to the alteration of the organic SOG can be obtained. One of the causes of organic SOG deterioration over time is that the condensation reaction of organosilane is not completely stopped in the coating solution. In general, preliminary curing is performed at a temperature near the boiling point of the solvent for the purpose of volatilizing the solvent in the coating solution. However, when pre-cured in a temperature range where the solvent remaining in the coating layer does not volatilize rapidly under an inert atmosphere, the condensation reaction of organosilane by heat is more rapid in the coating layer than when the solvent is volatilized. Proceed with By pre-curing conditions that intentionally generate this phenomenon, it is possible to homogenize the condensation state in the coating layer so as to cancel out the degree of deterioration due to the environmental difference of the coating solution, and thus firing the coating layer due to the aging of the coating solution. It has been found that later variations in thickness can be suppressed. The reason for the inert atmosphere is that the volatilization rate of various components is suppressed as compared to the presence of oxygen as in the air, and the amount of change in the fired film thickness due to the aging of the coating solution is reduced, thereby increasing the effect of the present invention. It is.

  From the above viewpoint, the preliminary curing temperature is 30 ° C. or higher and lower than 100 ° C. The pre-curing temperature is 30 ° C. or higher, preferably 40 ° C. or higher, more preferably 50 ° C. or higher, from the viewpoint that the volatile drying time of the solvent becomes appropriate and the film thickness uniformity of the coating is improved. Further, from the viewpoint of suppressing the rapid volatilization of the solvent and sufficiently exerting the effect in the present embodiment, the preliminary curing temperature is less than 100 ° C, preferably 90 ° C or less, more preferably 80 ° C or less. is there.

  In the present embodiment, the pre-curing step is terminated when the surface tackiness of the coating layer is reduced to such an extent that the above-described heating does not cause a problem in substrate transportation. Specifically, even if an object physically contacts the surface of the coating layer, it is sufficient that the object does not leave a mark. The pre-curing time is not particularly limited as long as the above-described surface tackiness is eliminated and no problem occurs on the substrate transport, but from the viewpoint of favorably proceeding the pre-curing, preferably 60 seconds or more, more preferably 90 seconds or more, more preferably 120 seconds or more, and from the viewpoint of shortening the time of the entire process, it is preferably 800 seconds or less, more preferably 700 seconds or less, and even more preferably 600 seconds or less.

  In the present embodiment, the preliminary curing needs to be performed in an inert atmosphere. In this disclosure, under an inert atmosphere means an oxygen concentration of 200 ppm or less. When the oxygen concentration is more than 200 ppm, the volatilization rate of the volatile component is high, and thus the effect in the present embodiment is not sufficiently exhibited. The oxygen concentration is preferably as low as possible, preferably 150 ppm or less, more preferably 100 ppm or less.

  In addition, after the heating at a temperature of 30 ° C. or more and less than 100 ° C. in the pre-curing step, additional pre-curing may be performed at a temperature of 100 ° C. or more and less than 400 ° C. before the fired silica-based film forming step described later. . In this case, the advantage that the film thickness uniformity of the coating is particularly good is obtained. The additional precuring can be performed in the air, oxygen, or steam oxidation atmosphere in addition to the inert atmosphere described above, and is preferably performed in an inert atmosphere or an air atmosphere. The temperature of the additional pre-curing can be preferably 100 ° C. or higher, more preferably 140 ° C. or higher from the viewpoint of sufficiently volatilizing the solvent, and preferably from the viewpoint of good film thickness uniformity. It can be below 400 ° C, more preferably below 300 ° C. Further, the additional precuring time is preferably 60 seconds or more, more preferably 90 seconds or more, and still more preferably 120 seconds or more, from the viewpoint of sufficiently volatilizing the solvent, and the film thickness uniformity of the coating becomes good. From the viewpoint, it is preferably 800 seconds or shorter, more preferably 700 seconds or shorter, and further preferably 600 seconds or shorter.

  Next, in the fired silica-based film forming step, the coating layer that has undergone the above-described pre-curing step and any additional pre-curing is heated to fire the coating layer. Examples of the heating method include heating application using a hot plate, an oven, a furnace, and the like. The atmosphere at the time of heating and firing is not limited as long as the desired functionality of the silica-based coating can be obtained, but it is performed in an inert atmosphere from the viewpoint of safety without causing combustion in the apparatus. Is preferred. The firing temperature is in the range of 400 ° C to 800 ° C. When the temperature is 400 ° C. or higher, sufficient baking is performed so that components unnecessary for the coating volatilize. Moreover, since the temperature of 800 degrees C or less is below the temperature which organosilane thermally decomposes, the functionality as a film can be ensured. The heating temperature is preferably 400 ° C. or higher, more preferably 500 ° C. or higher, preferably 800 ° C. or lower, more preferably 750 ° C. or lower. The heating time is preferably 1 minute or more, more preferably 10 minutes or more, and further preferably 30 minutes or more, from the viewpoint of sufficient baking for the components unnecessary for the coating to volatilize, and the process time is short. From the viewpoint of better, it is preferably 24 hours or less, more preferably 4 hours or less, and still more preferably 2 hours or less.

  Hereinafter, although an example and a comparative example are given and the present invention is further explained, the present invention is not limited to this.

(Manufacture of coating solution)
Production Example-1
In a 200 mL eggplant-shaped flask, 10.40 g of tetraethoxysilane and 20.63 g of ethanol were added and stirred. Subsequently, 1.53 g of 0.7 mass% nitric acid aqueous solution and 2.08 g of water were added dropwise at room temperature while stirring the solution in the eggplant flask using a dropping funnel. After completion of dropping, a cooling tube was set, and the mixture was heated and stirred at 50 ° C. for 2 hours using an oil bath. After heating and stirring, 60 g of propylene glycol monomethyl ether (PGME: boiling point 120 ° C.) was charged into the eggplant flask, and the solvent was distilled off under reduced pressure using an evaporator until the concentration reached 15% by mass in terms of SiO ₂ . Further, 30 g of PGME was charged into the eggplant flask and the solvent was distilled off using an evaporator to obtain a condensation reaction product solution having a concentration of 15% by mass in terms of SiO ₂ .

Production Example-2
In a 200 mL eggplant-shaped flask, 4.4 g of tetraethoxysilane, 11.6 g of methyltrimethoxysilane, and 20 g of ethanol were added and stirred. A mixed aqueous solution of 11.5 g of water and an appropriate amount of concentrated nitric acid for pH adjustment was added dropwise at room temperature while stirring the solution in the eggplant flask using a dropping funnel to adjust the pH to 6-7. After completion of dropping, the mixture was stirred for 30 minutes and allowed to stand for 24 hours to obtain a polysiloxane compound. 47.6 g of this polysiloxane compound was placed in a four-necked 500 mL flask having a distillation tower and a dropping funnel (PL-06 (water-dispersed silica particles having an average primary particle diameter of 6 nm and a concentration of 6.3% by mass, manufactured by Fuso Chemical Industries)). Then, 80 g of ethanol was added and the mixture was added dropwise to the mixture stirred for 5 minutes at room temperature. After completion of the addition, the mixture was stirred for 30 minutes and refluxed for 4 hours. After refluxing, 150 g of propylene glycol methyl ethyl acetate (PGMEA: boiling point 145 ° C.) was added, the temperature of the oil bath was raised, methanol, ethanol, water and nitric acid were distilled off from the distillation line, and the PGMEA solution of the condensation reaction product was removed. Obtained. By concentrating the PGMEA solution of the condensation reaction product, a condensation reaction product solution having a concentration of 20% by mass in terms of SiO ₂ was obtained.

(Evaluation of aging stability of coating solution by film thickness change)
Half of the condensation reaction product was stored frozen at −20 ° C. for 1 week, and the remaining half was stored at 23 ° C. for 1 week at room temperature, and then each spin coater (manufactured by Tokyo Electron, Clean Track Mk-8, 8 inch silicon wafer). ) For 30 seconds at 1600 rpm. After this coating film was pre-cured under the conditions of the following examples and comparative examples, nitrogen was passed through the furnace at a rate of 25 L / min using a vertical firing furnace (manufactured by Koyo Lindberg, VF-2000S), and the temperature rose from 23 ° C. The temperature was raised to 600 ° C. at a temperature rate of 5 ° C./min, and the firing step was performed by holding at 600 ° C. for 30 minutes to obtain a silica-based coating. The film thickness of the silica-based film was measured by using a spectroscopic ellipsometer (manufactured by HORIBA JOBINYVON, UVISEL), and the temporal stability was evaluated from the rate of film thickness change. As a criterion for determining the stability over time, the stability over time was set to be good when the film thickness change rate was less than 5%, and the stability over time was set to be poor when the change rate was 5% or more. Furthermore, the case where the rate of change in film thickness was less than 3% was considered particularly good.
Film thickness change rate (%) = ((film thickness of silica-based film prepared with 23 ° C. storage condensation reaction solution) / (film thickness of silica-based film prepared with −20 ° C. storage condensation reaction solution) −1) × 100

Example 1
About the condensation reaction liquid synthesize | combined in manufacture example-1, evaluation was implemented based on the evaluation method of the temporal stability by the said film thickness change. Here, the pre-curing conditions are an oxygen concentration of 200 ppm and a hot plate at 80 ° C. for 300 seconds. As a result, the film thickness change rate when the condensation reaction solution was stored frozen and stored at room temperature was less than 5%, and the stability over time was good.

Example 2
About the condensation reaction liquid synthesize | combined in manufacture example-1, evaluation was implemented based on the evaluation method of the temporal stability by the said film thickness change. Here, pre-curing conditions are an oxygen concentration of 200 ppm and a hot plate at 50 ° C. for 600 seconds. As a result, the film thickness change rate when the condensation reaction solution was stored frozen and stored at room temperature was less than 5%, and the stability over time was good.

Example 3
About the condensation reaction liquid synthesize | combined in manufacture example-2, evaluation was implemented based on the evaluation method of the temporal stability by the said film thickness change. Here, the pre-curing conditions are an oxygen concentration of 200 ppm and a hot plate at 80 ° C. for 300 seconds. As a result, the film thickness change rate when the condensation reaction solution was stored frozen and at room temperature was less than 3%, and the stability over time was particularly good.

Example 4
About the condensation reaction liquid synthesize | combined in manufacture example-2, evaluation was implemented based on the evaluation method of the temporal stability by the said film thickness change. Here, the pre-curing conditions are an oxygen concentration of 200 ppm, 80 ° C. for 300 seconds on a hot plate, and 110 ° C. for 300 seconds in an air atmosphere on the hot plate as a subsequent additional pre-curing. As a result, the film thickness change rate when the condensation reaction solution was stored frozen and at room temperature was less than 3%, and the stability over time was particularly good.

Comparative Example 1
About the condensation reaction liquid synthesize | combined in manufacture example-1, evaluation was implemented based on the evaluation method of the temporal stability by the said film thickness change. Here, the pre-curing conditions are 80 ° C. and 300 seconds on a hot plate in an air atmosphere. As a result, when the condensation reaction solution was stored frozen and stored at room temperature, the rate of change in film thickness was 5% or more, and the stability over time was poor.

Comparative Example 2
About the condensation reaction liquid synthesize | combined in manufacture example-1, evaluation was implemented based on the evaluation method of the temporal stability by the said film thickness change. Here, the pre-curing conditions are an oxygen concentration of 200 ppm and 110 ° C. for 300 seconds on a hot plate. As a result, when the condensation reaction solution was stored frozen and stored at room temperature, the film thickness difference was 5% or more, and the temporal stability was poor.

Comparative Example 3
About the condensation reaction liquid synthesize | combined in manufacture example-2, evaluation was implemented based on the evaluation method of the temporal stability by the said film thickness change. Here, the pre-curing conditions are an oxygen concentration of 200 ppm and 110 ° C. for 300 seconds on a hot plate. As a result, when the condensation reaction solution was stored frozen and stored at room temperature, the rate of change in film thickness was 5% or more, and the stability over time was poor.

Comparative Example 4
About the condensation reaction liquid synthesize | combined in manufacture example-2, evaluation was implemented based on the evaluation method of the temporal stability by the said film thickness change. Here, the pre-curing conditions are an oxygen concentration of 200 ppm and a hot plate at 23 ° C. for 600 seconds. As a result, when the condensation reaction solution was stored frozen and stored at room temperature, the rate of change in film thickness was 5% or more, and the stability over time was poor.

  The method of the present invention is useful, for example, in forming an insulating film for a semiconductor device.

Claims (3)

A coating layer forming step of forming a coating layer by coating a coating solution containing a condensation reaction product of organosilane on a substrate;
A preliminary curing step to further proceed the condensation reaction of the coating layer by heating the coating layer of oxygen concentration 200ppm or less at a temperature of 50 ° C. or higher 80 ° C. or less in an atmosphere,
After the preliminary curing step, a fired silica-based film forming step of forming a fired silica-based film by heating the coating layer at a temperature of 400 ° C. or higher and 800 ° C. or lower;
A method for producing a silica-based coating, comprising:   The method for producing a silica-based film according to claim 1, wherein the organosilane contains tetraethoxysilane.   The manufacturing method of the silica type coating film of Claim 1 or 2 with which the said coating liquid contains a silica particle.