Silane compound polymer, semiconductor insulating material, and semiconductor insulating film-forming agent

Abstract

The present invention provides: a silane compound polymer comprising repeating units [repeating units (1)] represented by formula (a-1) (a-1) HSiO3 / 2 <sb / >, and repeating units [repeating units (2)] represented by formula (a-2) (a-2) R1SiO3 / 2 [R1 represents an unsubstituted C6-12 aryl group or a C6-12 aryl group having a substituent]; a semiconductor insulating material comprising the silane compound polymer; and a semiconductor insulating film-forming agent containing the silane compound polymer.

Description

Silane compound polymer, insulating material for semiconductor, and insulating film forming agent for semiconductor

[0001] The present invention relates to a silane compound polymer that is suitably used as an insulating material, an insulating material for semiconductors that comprises this silane compound polymer, and a semiconductor insulating film forming agent that contains the silane compound polymer.

[0002] Conventionally, SiO2 has been deposited as an insulating film for semiconductor devices and the like by a vacuum process such as thermal CVD. ２ However, since vacuum processes are not suitable for forming insulating films that fill deep recesses, the SOG (Spin on Glass) method has been attracting attention in recent years.

[0003] In the SOG method, an insulating film is usually formed by applying an insulating film-forming liquid by spin coating and curing the resulting coating. For example, Patent Document 1 describes a silicon oxide film-forming composition containing a solvent, a silicon oxide-forming compound dissolved and / or dispersed in the solvent, and silicon particles dispersed in the solvent, and a method for forming a silicon oxide film using this composition.

[0004] JP 2015-18952 A

[0005] Patent Document 1 describes that the SOG method can form a relatively thick silicon oxide film in a short time, and that the use of the composition described in Patent Document 1 can form a silicon oxide film that is less susceptible to cracking. According to the examples in Patent Document 1, silicon particles are considered to be an important component for forming a thick film and preventing cracking. However, when using a composition containing silicon particles, the silicon particles must be converted into silicon oxide, which requires heat treatment under harsh conditions (in the example, 900°C for 30 minutes). Therefore, a method for forming an insulating film more efficiently has been sought.

[0006] The present invention has been made under these circumstances, and aims to provide a silane compound polymer that is suitably used as an insulating material, an insulating material for semiconductors comprising this silane compound polymer, and a semiconductor insulating film forming agent containing the silane compound polymer.

[0007] In order to solve the above problems, the present inventors have conducted extensive research on silane compound polymers. As a result, they have found that: (1) a silane compound polymer containing a hydrogen atom bonded to a silicon atom has excellent curing properties, and therefore, by using such a silane compound polymer as an insulating material, an insulating film (cured product) can be efficiently formed in a short time; (2) a cured product obtained by curing a silane compound polymer containing a hydrogen atom bonded to a silicon atom is prone to cracking; (3) the occurrence of cracks in a cured product can be suppressed by introducing a repeating unit containing an aryl group into a silane compound polymer containing a hydrogen atom bonded to a silicon atom; and (4) a silane compound polymer containing a hydrogen atom bonded to a silicon atom and an aryl group has a small weight loss rate even when heated at a temperature exceeding the normal curing temperature, and therefore, a higher temperature can be selected as the curing condition for this silane compound polymer, thereby completing the present invention.

[0008] Thus, according to the present invention, there are provided the following silane compound polymers [1] to [8], insulating materials for semiconductors [9], and semiconductor insulating film forming agents

[10] to

[14] . [1] A compound represented by the following formula (a-1):

[0009]

[0010] and a repeating unit represented by the following formula (a-2):

[0011]

[0012] [R １represents an unsubstituted aryl group having 6 to 12 carbon atoms, or a substituted aryl group having 6 to 12 carbon atoms. (2) A silane compound polymer having a repeating unit [repeating unit (2)] represented by the following formula: [2] The silane compound polymer according to [1], wherein the amount of the repeating unit (1) is 10 to 45 mol % based on the total amount of the repeating unit (1) and the repeating unit (2). [3] The silane compound polymer according to [1] or [2], wherein the total amount of the repeating unit (1) and the repeating unit (2) is 70 to 100 mol % based on the total amount of repeating units in the silane compound polymer. [4] The silane compound polymer according to any one of [1] to [3], wherein the mass average molecular weight (Mw) is 1,500 to 50,000. [5] The silane compound polymer according to any one of [1] to [4], wherein the silane compound polymer is a silane compound polymer obtained by hydrolysis and polycondensation of an alkoxysilane compound, and wherein the residual alkoxy group ratio is 2.0% or less. [6] When a curability evaluation test is carried out under the following conditions, the thickness reduction rate (X ｔ The silane compound polymer according to any one of [1] to [5], wherein the silane compound polymer has a thickness of 20% or less. [Curability Evaluation Test] A1: A 2 μm thick film of the silane compound polymer is formed on a silicon wafer. A2: The film obtained in A1 above is heated at 250° C. for 1 minute to be cured. A3: The cured film obtained in A2 above is moved to a 23° C. environment and left there until it cools to 23° C. A4: After A3 above, the cured film is immersed in diethylene glycol dimethyl ether at 23° C. for 10 minutes and dried on a hot plate heated to 150° C. for 1 minute.

[0013]

[0014] [In formula (F1), T １ represents the thickness of the silane compound polymer film before A4, and T ２represents the thickness of the film of the silane compound polymer after A4.] [7] The silane compound polymer according to any one of [1] to [6], which does not crack when subjected to a crack resistance evaluation test under the following conditions. [Crack Resistance Evaluation Test] B1: A film of the silane compound polymer having a thickness of 1 μm is formed on a silicon wafer. B2: The film obtained in B1 above is heated at 250° C. for 1 minute to be cured. B3: The cured film obtained in B2 above is transferred to an environment of 23° C. and left there until it cools to 23° C. [8] When thermogravimetry is performed under the following conditions, the weight loss rate (X ｍ The silane compound polymer according to any one of [1] to [7], wherein the silane compound polymer has a porosity of 7% or less. [Thermogravimetric Measurement] C1: The silane compound polymer is heated at 200°C for 120 minutes. C2: After C1, the silane compound polymer is heated to 500°C at a rate of 10°C / min.

[0015]

[0016] [In formula (F2), M １ represents the weight of the silane compound polymer before C1, and M ２ represents the weight of the silane compound polymer after C2.] [9] An insulating material for semiconductors comprising the silane compound polymer according to any one of [1] to [8] above.

[10] A semiconductor insulating film forming agent containing the silane compound polymer according to any one of [1] to [8] above and a solvent.

[11] The semiconductor insulating film forming agent according to

[10] , wherein the solvent has a boiling point of 150°C or higher.

[12] The semiconductor insulating film forming agent according to

[10] or

[11] , wherein the solvent is a polyether solvent.

[13] The semiconductor insulating film forming agent according to any one of

[10] to

[12] , wherein the total amount of the silane compound polymer according to any one of [1] to [8] above and the solvent is 80 mass% or more of the total amount of the semiconductor insulating film forming agent.

[14] The semiconductor insulating film forming agent according to any one of

[10] to

[13] , which is substantially free of reactive compounds other than the silane compound polymer according to any one of [1] to [8] above. In the explanations of tests and measurements in this specification, the term "cured product of a silane compound polymer" may be abbreviated to "silane compound polymer."

[0017] According to the present invention, there are provided a silane compound polymer that is suitably used as an insulating material, an insulating material for semiconductors comprising this silane compound polymer, and a semiconductor insulating film forming agent containing the silane compound polymer.

[0018] In this specification, for preferred numerical ranges (e.g., ranges of content, etc.), the lower limit and upper limit values ​​described in stages can be independently combined. For example, the description "preferably 10 to 90, more preferably 30 to 60" can be combined with the "preferable lower limit (10)" and the "more preferable upper limit (60)" to form "10 to 60."

[0019] The present invention will be described in detail below, divided into the following sections: 1) silane compound polymer and insulating material for semiconductor, and 2) semiconductor insulating film forming agent.

[0020] 1) Silane Compound Polymer and Semiconductor Insulating Material The silane compound polymer of the present invention is a silane compound polymer having a repeating unit represented by the above formula (a-1) and a repeating unit represented by the above formula (a-2).

[0021] [Repeating Unit Constituting Silane Compound Polymer] The silane compound polymer of the present invention has a repeating unit represented by the following formula (a-1) [repeating unit (1)].

[0022]

[0023] The silane compound polymer having the repeating unit (1) tends to have excellent curability, and therefore the silane compound polymer of the present invention is suitable for use as an insulating material for semiconductors.

[0024] The silane compound polymer of the present invention has a repeating unit represented by the following formula (a-2) [repeating unit (2)].

[0025]

[0026] In formula (a-2), R １ represents an unsubstituted aryl group having 6 to 12 carbon atoms or a substituted aryl group having 6 to 12 carbon atoms.

[0027] When a silane compound polymer has only the repeating unit (1), the cured product of the silane compound polymer tends to be prone to cracking. The repeating unit (2) solves this problem, and by introducing the repeating unit (2) into a silane compound polymer having the repeating unit (1), the cured product of the silane compound polymer becomes less prone to cracking. For this reason, the silane compound polymer of the present invention is suitable for use as an insulating material for semiconductors.

[0028] R １ Examples of the unsubstituted aryl group having 6 to 12 carbon atoms include a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a tolyl group, and a xylyl group. １ Examples of the aryl group having 6 to 12 carbon atoms and having the substituent include the above-mentioned unsubstituted aryl group having 6 to 12 carbon atoms in which one or more hydrogen atoms have been substituted with a substituent. Examples of the substituent include a cyano group, an amino group, an acryloyloxy group, a methacryloyloxy group, an epoxy group, and a halogen atom such as a fluorine atom, a chlorine atom, or a bromine atom.

[0029] In the silane compound polymer of the present invention, the amount of the repeating unit (1) is preferably 10 to 45 mol %, more preferably 15 to 35 mol %, and even more preferably 20 to 30 mol %, based on the total amount of the repeating unit (1) and the repeating unit (2). A silane compound polymer having the repeating unit (1) in the above range has a good balance between curability and crack resistance, and is suitable for use as an insulating material for semiconductors.

[0030] In the silane compound polymer of the present invention, the total amount of the repeating units (1) and (2) is preferably 70 to 100 mol %, more preferably 80 to 100 mol %, and even more preferably 90 to 100 mol %, based on the total amount of repeating units in the silane compound polymer. A silane compound polymer in which the total amount of the repeating units (1) and (2) is 70 mol % or more based on the total amount of repeating units in the silane compound polymer has a good balance between curability and crack resistance, and is suitable for use as an insulating material for semiconductors.

[0031] When the silane compound polymer of the present invention has a repeating unit [repeating unit (3)] other than the repeating unit (1) and the repeating unit (2), examples of the repeating unit (3) include a repeating unit derived from a monofunctional silane compound such as trimethylmethoxysilane, a repeating unit derived from a bifunctional silane compound such as dimethyldimethoxysilane, a repeating unit derived from a trifunctional silane compound (excluding the repeating unit (1) and the repeating unit (2)), and a repeating unit derived from a tetrafunctional silane compound such as tetramethoxysilane.

[0032] [Physical Properties of Silane Compound Polymer] The mass average molecular weight (Mw) of the silane compound polymer of the present invention is preferably 1,500 to 50,000, more preferably 1,750 to 20,000, even more preferably 2,000 to 10,000, and particularly preferably 3,000 to 9,000. The molecular weight distribution (Mw / Mn) of the silane compound polymer of the present invention is not particularly limited, but is usually 1.0 to 10.0, preferably 1.1 to 6.0. The mass average molecular weight (Mw) and number average molecular weight (Mn) can be determined, for example, as values ​​converted into standard polystyrene by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent.

[0033] A silane compound polymer having a mass-average molecular weight within the above range tends to have a better balance between curability and crack resistance. Furthermore, when a coating solution containing a silane compound polymer having a mass-average molecular weight of 1,500 or more is used, a thick film can be efficiently formed by a spin coating method, making such a silane compound polymer suitable as an insulating material for semiconductors.

[0034] The silane compound polymer of the present invention may be any of a random copolymer, a block copolymer, a graft copolymer, an alternating copolymer, etc., but a random copolymer is preferred from the viewpoint of ease of production, etc. The structure of the silane compound polymer of the present invention may be any of a ladder structure, a double-decker structure, a cage structure, a partially cleaved cage structure, a cyclic structure, and a random structure.

[0035] As will be described later, the silane compound polymer of the present invention can be efficiently produced by hydrolysis and polycondensation of an alkoxysilane compound. Hereinafter, among the silane compound polymers of the present invention, one obtained by hydrolysis and polycondensation of an alkoxysilane compound may be referred to as a "silane compound polymer (i)."

[0036] The residual alkoxy group rate of the silane compound polymer (i) is preferably 2.0% or less, more preferably 1.0% or less, and even more preferably 0.5% or less. The residual alkoxy group rate of the silane compound polymer (i) represents the degree to which the alkoxy groups contained in the alkoxysilane compound used as a monomer remain in the silane compound polymer (i). A silane compound polymer (i) having a residual alkoxy group rate of 2.0% or less is one in which the hydrolysis reaction of the alkoxysilane compound has progressed sufficiently and contains many Si—O—Si bonds and Si—OH bonds. Such silane compound polymers (i) are relatively large molecules and reactive, making them suitable as insulating materials for semiconductors.

[0037] The residual alkoxy group ratio of the silane compound polymer (i) １ For example, when a silane compound polymer (i) is synthesized using triethoxysilane and phenyltriethoxysilane, the １ The residual alkoxy group ratio of the silane compound polymer (i) can be calculated by measuring H-NMR and determining the ratio of the total amount of hydrogen atoms and phenyl groups bonded to silicon atoms to the amount of ethoxy groups based on the peak area ratio.

[0038] As described above, the silane compound polymer of the present invention has excellent curability due to the repeating unit (1) containing a hydrogen atom bonded to a silicon atom. Therefore, by heating the silane compound polymer at about 250°C, the curing reaction can be sufficiently promoted, and a cured product that is difficult to dissolve in a solvent is produced.

[0039] For example, when a curability evaluation test was carried out under the following conditions, the silane compound polymer of the present invention exhibited a thickness reduction rate (Xｔ ) is preferably 20% or less, more preferably 10% or less. [Curability Evaluation Test] A1: A 2 μm thick film of a silane compound polymer is formed on a silicon wafer. A2: The film obtained in A1 above is heated at 250° C. for 1 minute to be cured. A3: The cured film obtained in A2 above is moved to a 23° C. environment and left there until it cools to 23° C. A4: After A3 above, the cured film is immersed in diethylene glycol dimethyl ether at 23° C. for 10 minutes and dried on a hot plate heated to 150° C. for 1 minute.

[0040]

[0041] In formula (F1), T １ represents the thickness of the silane compound polymer film before A4, and T ２ represents the thickness of the silane compound polymer film after A4. １ and T ２ can be measured using, for example, a stylus surface profiler (Dektak 150 manufactured by ULVAC).

[0042] As described above, the silane compound polymer of the present invention has a repeating unit (2) containing an aryl group, and therefore cracks are unlikely to occur in the cured product. Therefore, when the silane compound polymer is heated and cured and then allowed to cool to room temperature, cracks are unlikely to occur in the cured product. For example, when a crack resistance evaluation test is conducted under the following conditions, the silane compound polymer of the present invention preferably does not cause cracks in a film having a thickness of 1 μm, and more preferably does not cause cracks in both a film having a thickness of 1 μm and a film having a thickness of 2 μm.

[0043] [Crack Resistance Evaluation Test] D1: A silane compound polymer film having a thickness of 1 μm or 2 μm is formed on a silicon wafer. D2: The film obtained in D1 is heated at 250° C. for 1 minute to be cured. D3: The cured film obtained in D2 is transferred to a 23° C. environment and left there until it cools down to 23° C.

[0044] Furthermore, since the silane compound polymer of the present invention contains a hydrogen atom bonded to a silicon atom and an aryl group, it is unlikely to undergo weight loss or volume shrinkage even when baked at a temperature higher than a normal curing temperature, and cracks are unlikely to occur. For example, when thermogravimetry is performed under the following conditions, the silane compound polymer of the present invention exhibits a weight loss rate (X ｍ ) is preferably 7% or less, more preferably 5% or less.

[0045] [Thermogravimetry] C1: The silane compound polymer is heated for 120 minutes at 200° C. C2: After C1, the silane compound polymer is heated to 500° C. at a rate of 10° C. / min.

[0046]

[0047] In formula (F2), M １ represents the weight of the silane compound polymer before C1, and M ２ represents the weight of the silane compound polymer after C2.

[0048] As described above, the silane compound polymer of the present invention has excellent curability and is less likely to crack in the cured product. Furthermore, it can be baked at a higher temperature depending on the purpose. Therefore, the silane compound polymer of the present invention is suitable for use as an insulating material for semiconductors.

[0049] [Method for Producing Silane Compound Polymer] The method for producing the silane compound polymer of the present invention is not particularly limited. For example, the silane compound polymer of the present invention can be produced by carrying out a step (step PO) of hydrolyzing and polycondensing a trifunctional alkoxysilane compound corresponding to a desired repeating unit in the presence of water and an acid catalyst.

[0050] Step PO is a step of hydrolyzing and polycondensing a trifunctional alkoxysilane compound corresponding to the desired repeating unit in the presence of water and an acid catalyst.

[0051] In the step PO, for example, a compound represented by the following formula (a-3) and a compound represented by the following formula (a-4) are used as the trifunctional alkoxysilane compound.

[0052]

[0053] In formula (a-4), R １ represents the same meaning as above. OR represents an alkoxy group. OR may be the same or different.

[0054] The number of carbon atoms in the alkoxy group represented by OR is preferably 1 to 6, and more preferably 1 to 3. Examples of the alkoxy group represented by OR include a methoxy group, an ethoxy group, and a propoxy group.

[0055] Specific examples of the trifunctional alkoxysilane compound represented by formula (a-3) include trimethoxysilane, triethoxysilane, tripropoxysilane, etc. These trifunctional alkoxysilane compounds can be used alone or in combination of two or more.

[0056] Specific examples of the trifunctional alkoxysilane compound represented by formula (a-4) include phenyltrimethoxysilane, phenyltriethoxysilane, phenyltrippropoxysilane, pentafluorophenyltrimethoxysilane, pentafluorophenyltriethoxysilane, pentafluorophenyltrippropoxysilane, etc. These trifunctional alkoxysilane compounds can be used alone or in combination of two or more.

[0057] In the method for producing a silane compound polymer of the present invention, the molar ratio of the compound represented by formula (a-3) to the compound represented by formula (a-4) [compound represented by formula (a-3):compound represented by formula (a-4)] is preferably 10:90 to 45:55, more preferably 15:85 to 35:65, and even more preferably 20:80 to 30:70.

[0058] In step PO, in addition to the trifunctional alkoxysilane compounds, monofunctional alkoxysilane compounds such as trimethylmethoxysilane, bifunctional alkoxysilane compounds such as dimethyldimethoxysilane, trifunctional alkoxysilane compounds other than the compounds represented by formula (a-3) and formula (a-4), and tetrafunctional alkoxysilane compounds such as tetramethoxysilane may be used as monomers.

[0059] In the method for producing a silane compound polymer of the present invention, the total amount of the compound represented by formula (a-3) and the compound represented by formula (a-4) is preferably 70 to 100 mol %, more preferably 80 to 100 mol %, and even more preferably 90 to 100 mol %, based on the total amount of monomers.

[0060] In the step PO, it is preferable to add water to the reaction system in an amount sufficient to sufficiently hydrolyze the hydrolyzable groups contained in the monomers (for example, "OR" in formula (a-3) and formula (a-4)).

[0061] The amount of water added is preferably such that the molar ratio M of water to alkoxy groups, calculated by the following formula (F3), is 1.0 or more, more preferably 1.0 to 5.0, and even more preferably 1.0 to 3.0.

[0062]

[0063] In formula (F3), M Ｈ２Ｏ is the amount of water (molar number) added to the reaction system, and M ＯＲ is the total number of alkoxy groups in the monomer (total number of moles). For example, when 6.0 moles of water are added to 1.0 mole of a trifunctional alkoxysilane compound, the molar ratio M is 6.0 / 3.0 (=2.0).

[0064] When the molar ratio M is 1.0 or more, the hydrolysis reaction of the monomers can be sufficiently progressed, and a silane compound polymer having excellent curability can be easily obtained.

[0065] Examples of the acid catalyst used in step (PO) include inorganic acids such as phosphoric acid, hydrochloric acid, boric acid, sulfuric acid, and nitric acid; and organic acids such as formic acid, citric acid, acetic acid, methanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, and p-toluenesulfonic acid. Among these, at least one selected from phosphoric acid, hydrochloric acid, boric acid, sulfuric acid, formic acid, citric acid, acetic acid, and methanesulfonic acid is preferred.

[0066] The amount of the acid catalyst used is usually 0.05 to 10 mol %, preferably 0.1 to 5 mol %, based on the total amount of monomers. By adjusting the amount of the acid catalyst used, the polycondensation reaction can be allowed to proceed appropriately, and a silane compound polymer having the desired molecular weight can be obtained.

[0067] Step PO can be carried out, for example, by placing a trifunctional alkoxysilane compound, water, and an acid catalyst in a reaction vessel and stirring the resulting mixture. In addition to these components, an organic solvent may also be present in the reaction vessel. The presence of an organic solvent in the reaction vessel allows the polymerization reaction to continue even if a solid silane compound polymer is produced during the polymerization reaction.

[0068] The organic solvent used in step PO is not particularly limited as long as it dissolves the trifunctional alkoxysilane compound used as a raw material. However, a high-boiling point solvent (e.g., a solvent with a boiling point of 150°C or higher) is preferred as the organic solvent, as this is less likely to volatilize during step PO and allows step PO to be carried out stably.

[0069] Examples of high-boiling point solvents include polyether solvents such as dipropylene glycol dimethyl ether (boiling point 171°C), diethylene glycol dimethyl ether (boiling point 162°C), and diethylene glycol ethyl methyl ether (boiling point 176°C); ester solvents such as γ-butyrolactone (boiling point 204°C), ethyl lactate (boiling point 154°C), 3-methoxybutyl acetate (boiling point 171°C), and ethylene glycol monoethyl ether acetate (boiling point 156°C); ketone solvents such as cyclohexanone (boiling point 156°C); amide solvents such as N,N-dimethylformamide (boiling point 153°C), N,N-dimethylacetamide (boiling point 165°C), and N-methylpyrrolidone (boiling point 202°C); and sulfoxide solvents such as dimethyl sulfoxide (boiling point 189°C). Among these, polyether solvents are preferred because they are less susceptible to reaction even at high temperatures.

[0070] When an organic solvent is used in step PO, the organic solvent is preferably used in an amount of 0.05 to 3 times, more preferably 0.1 to 1.5 times, by volume, the amount of the trifunctional alkoxysilane compound. When the reaction solution obtained in step PO is used as is as an insulating film forming agent, it is preferable to adjust the amount of the organic solvent used in consideration of the concentration of the silane compound polymer in the insulating film forming agent.

[0071] The reaction conditions for step PO are not particularly limited. The reaction temperature for step PO is usually 0 to 180° C., preferably 10 to 170° C. The reaction time for step PO is usually 30 minutes to 50 hours, preferably 1 to 24 hours.

[0072] The process PO may be carried out under constant conditions from start to finish (i.e., it may have one step), or it may have multiple steps with different reaction conditions.

[0073] After the step PO, the reaction liquid may be used as an insulating film forming agent as it is, or a step (step PU) of purifying the silane compound polymer produced in the step PO may be carried out. By carrying out the step PU, a highly pure silane compound polymer can be obtained.

[0074] An example of step PU is a purification step using a solvent extraction method. Examples of purification steps using a solvent extraction method include those having the following steps: (Step PU-I) If necessary, volatilizing the solvent from the reaction solution, then adding a water-immiscible organic solvent or water, stirring the mixture, and then allowing it to stand to separate into an organic phase and an aqueous phase; (Step PU-II) A step of separating the organic phase produced in step PU-I and washing the organic phase with water if necessary; and (Step PU-III) A step of concentrating and drying the organic phase separated in step PU-II.

[0075] The amount of solvent and the type of organic solvent added in Step PU-I are not particularly limited as long as they are finally separated into an organic phase and an aqueous phase.

[0076] The silane compound polymer is usually contained in the organic phase. Therefore, in step PU-II, the organic phase produced in step PU-I is separated. Thereafter, the organic phase may be washed with water according to a conventional method.

[0077] Step PU-III can be carried out by a conventional method such as concentration treatment with an evaporator and vacuum drying treatment.

[0078] 2) Semiconductor Insulating Film Forming Agent The semiconductor insulating film forming agent of the present invention contains the silane compound polymer of the present invention (hereinafter referred to as "silane compound polymer (A)") and a solvent.

[0079] [Silane Compound Polymer (A)] The semiconductor insulating film forming agent of the present invention contains a silane compound polymer (A). As described above, the silane compound polymer (A) has excellent curability and is less likely to cause cracks in the cured product. Therefore, by using the semiconductor insulating film forming agent of the present invention, a semiconductor insulating film can be efficiently formed.

[0080] [Solvent] The solvent constituting the semiconductor insulating film forming agent of the present invention is not particularly limited as long as it dissolves the silane compound polymer (A). Therefore, when the silane compound polymer (A) is synthesized in the presence of an organic solvent and a homogeneous reaction solution is obtained, the same solvent as that used in the synthesis can be used as the solvent constituting the semiconductor insulating film forming agent of the present invention.

[0081] Examples of the solvent constituting the semiconductor insulating film forming agent of the present invention include solvents having a boiling point of 150°C or higher, such as polyether solvents such as dipropylene glycol dimethyl ether (boiling point 171°C), diethylene glycol dimethyl ether (boiling point 162°C), and diethylene glycol ethyl methyl ether (boiling point 176°C); ester solvents such as γ-butyrolactone (boiling point 204°C), ethyl lactate (boiling point 154°C), 3-methoxybutyl acetate (boiling point 171°C), and ethylene glycol monoethyl ether acetate (boiling point 156°C); ketone solvents such as cyclohexanone (boiling point 156°C); amide solvents such as N,N-dimethylformamide (boiling point 153°C), N,N-dimethylacetamide (boiling point 165°C), and N-methylpyrrolidone (boiling point 202°C); and sulfoxide solvents such as dimethyl sulfoxide (boiling point 189°C).

[0082] If a solvent having a boiling point of 150°C or higher is used, evaporation of the solvent during application of the semiconductor insulating film forming agent by spin coating can be avoided, and a film of more uniform thickness can be formed.

[0083] Among these, polyether solvents are preferred. Since polyether solvents easily form azeotropes with water, the use of polyether solvents allows the coating film to be dried efficiently in the drying step. In this specification, polyether solvents refer to compounds having ether groups at the interior and terminal ends of the hydrocarbon chain. Such compounds are stable even at high temperatures and are suitable as components of semiconductor insulating film forming agents.

[0084] [Semiconductor insulating film forming agent] The amount of silane compound polymer (A) contained in the semiconductor insulating film forming agent of the present invention is preferably 10 to 70 mass %, more preferably 15 to 65 mass %, and even more preferably 20 to 60 mass %, based on the total amount of the silane compound polymer (A) and the solvent. When the amount of silane compound polymer (A) is 10 mass % or more based on the total amount of the silane compound polymer (A) and the solvent, a thick semiconductor insulating film can be efficiently formed. When the amount of silane compound polymer (A) is 70 mass % or less based on the total amount of the silane compound polymer (A) and the solvent, a film of uniform thickness can be formed by spin coating.

[0085] The semiconductor insulating film forming agent of the present invention may contain components other than the silane compound polymer (A) and the solvent (hereinafter referred to as "other components"). Examples of other components include a curing catalyst and a surfactant.

[0086] The total amount of the silane compound polymer (A) and the solvent contained in the semiconductor insulating film forming agent of the present invention is preferably 80 mass % or more, more preferably 85 mass % or more, and even more preferably 90 mass % or more, of the total amount of the semiconductor insulating film forming agent.

[0087] The semiconductor insulating film forming agent of the present invention preferably does not substantially contain any reactive compounds other than the silane compound polymer (A). In this specification, "reactive compounds other than the silane compound polymer (A)" refers to compounds other than the silane compound polymer (A) that are reactive at 250°C or less. Examples of such compounds include silane coupling agents, isocyanate-based curing agents, and epoxy-based curing agents. Furthermore, "substantially does not contain" means that no reactive compounds other than the silane compound polymer (A) are intentionally added to the semiconductor insulating film forming agent.

[0088] By using a semiconductor insulating film forming agent that does not substantially contain any reactive compounds other than the silane compound polymer (A), a semiconductor insulating film that does not have cracks can be efficiently formed.

[0089] The semiconductor insulating film forming agent of the present invention can be prepared, for example, by mixing the silane compound polymer (A), a solvent, and other components in a predetermined ratio. When the silane compound polymer (A) is synthesized in a solvent, the reaction mixture may be used as the semiconductor insulating film forming agent of the present invention.

[0090] When forming a semiconductor insulating film using the semiconductor insulating film-forming agent of the present invention, the semiconductor insulating film-forming agent is typically applied, the resulting coating film is dried, and then the dried coating film is cured. Spin coating is preferably used when applying the semiconductor insulating film-forming agent. Conditions for drying the coating film of the semiconductor insulating film-forming agent include, for example, a drying temperature of typically 100 to 200°C, preferably 120 to 180°C, and a drying time of typically 10 to 300 seconds, preferably 40 to 120 seconds. Conditions for curing the dried coating film include, for example, a curing temperature of typically 200 to 350°C, preferably 230 to 300°C, and a curing time of typically 30 to 600 seconds, preferably 60 to 300 seconds.

[0091] By using the semiconductor insulating film forming agent of the present invention, it is possible to efficiently form a relatively thick semiconductor insulating film, for example, 0.1 to 5.0 μm, preferably 0.5 to 4.0 μm, and more preferably 1.0 to 3.0 μm.

[0092] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0093] Example 1 250 mmol (30.6 g) of trimethoxysilane and 750 mmol (148.7 g) of phenyltrimethoxysilane were weighed into a flask, and diethylene glycol dimethyl ether was added to adjust the monomer concentration to 30% by mass. Next, at 30°C, an aqueous formic acid solution (10 mmol (0.460 g) of formic acid diluted with 4500 mmol (81.0 g) of water) was added dropwise to the flask over 30 minutes. The contents of the flask were heated to 50°C and stirred for 2 hours. Subsequently, while distilling off volatiles from the contents of the flask, the contents of the flask were heated to 110°C and stirred for 2 hours, then to 160°C and stirred for 1 hour, to obtain a solution of a silane compound polymer.

[0094] [Examples 2 to 3, Comparative Examples 1 to 3] Solutions of silane compound polymers were obtained in the same manner as in Example 1, except that the amounts of silane compounds shown in Table 1 were used as monomers in the ratios shown in Table 1 (however, the total amount of silane compounds was 1,000 mmol).

[0095] The following measurements were carried out on the silane compound polymers obtained in Examples 1 to 3 and Comparative Examples 1 to 3. The results are shown in Table 1.

[0096] [Measurement of average molecular weight] The mass average molecular weight (Mw) of the silane compound polymer was measured using the following apparatus and conditions: Apparatus name: HLC-8220GPC manufactured by Tosoh Corporation Column: "TSK guard column SuperH-H", "TSK gel SuperHM-H", "TSK gel SuperHM-H", and "TSK gel SuperH2000" connected in sequence Solvent: tetrahydrofuran Standard substance: polystyrene Injection amount: 20 μl Measurement temperature: 40° C. Flow rate: 0.6 ml / min Detector: differential refractometer

[0097] [ １ H-NMR measurement] Apparatus name: AV-500 manufactured by Bruker Biospin １ H-NMR resonance frequency: 500 MHz Probe: 5 mmφ solution probe Measurement temperature: room temperature (25°C) Repetition time: 1 s Number of accumulations: 16

[0098] < １H-NMR sample preparation method> Silane compound polymer concentration: 3% Measurement solvent: acetone-d6 Internal standard: TMS

[0099] [Alkoxy group residual ratio] １ Based on the results of H-NMR measurement, the ratio of alkoxy groups to methyl groups and phenyl groups was determined, and the residual alkoxy group ratio of the silane compound polymer was calculated.

[0100] [Curability Evaluation Test] A curability evaluation test was carried out under the following conditions. A solution of a silane compound polymer was spin-coated onto a silicon wafer, and the wafer was heated on a hot plate heated to 150°C for 1 minute to volatilize the solvent, forming a 2 μm-thick film of the silane compound polymer. The wafer was then heated on a hot plate heated to 250°C for 1 minute to harden the film of the silane compound polymer. The obtained cured film was transferred to an environment of 23°C and left there until it cooled to 23°C. The thickness (T １ After measuring the thickness (T ２ ) was measured, and the thickness reduction rate (X ｔ ) was calculated, and the curability of the silane compound polymer was evaluated according to the following criteria. １ ), (T ２ ) was measured using a stylus surface profiler (Dektak 150, manufactured by ULVAC).

[0101]

[0102] A: Thickness reduction rate (X ｔ ) is 20% or less. F: Thickness reduction rate (X ｔ ) is over 20%.

[0103] [Crack Resistance Evaluation Test] A crack resistance evaluation test was conducted under the following conditions. A solution of a silane compound polymer was spin-coated onto a silicon wafer, and the wafer was heated on a hot plate heated to 150°C for 1 minute to volatilize the solvent and form a 2 μm-thick film of a silane compound polymer. The wafer was then heated on a hot plate heated to 250°C for 1 minute to harden the silane compound polymer film. The resulting cured film was transferred to a 23°C environment and allowed to cool to 23°C, after which the presence or absence of cracks was examined. The same experiment as above was conducted, except that a 1 μm-thick film of a silane compound polymer was formed instead of the 2 μm-thick film of a silane compound polymer. The crack resistance was evaluated according to the following criteria: A: No cracks occurred in both the 2 μm-thick film and the 1 μm-thick film. B: Cracks occurred only in the 2 μm-thick film. F: Cracks occurred in both the 2 μm-thick film and the 1 μm-thick film.

[0104] [Thermogravimetric measurement] Thermogravimetric measurement was carried out under the following conditions. A test sample was obtained by spin-coating a solution of a silane compound polymer. Then, using a thermal analyzer (Shimadzu Corporation: DTG-60), thermogravimetric measurement was carried out under the following conditions. The test sample was heated at 150°C for 90 minutes to volatilize the solvent, and the weight M of the test sample after the solvent volatilization was １ Then, the temperature was increased to 200°C and heated for 120 minutes to cure the silane compound polymer. After that, the temperature was increased to 500°C at a rate of 10°C / min, and the weight M of the test sample at that time was measured. ２ was measured, and the weight loss rate (X ｍ ) was calculated.

[0105]

[0106]

[0107] The following can be seen from the above Examples and Comparative Examples. The silane compound polymers of Examples 1 to 3 have excellent curability and good crack resistance. Furthermore, they have a low weight loss rate. On the other hand, the silane compound polymer of Comparative Example 1 has only methyl groups as side chains. Therefore, the silane compound polymer of Comparative Example 1 has poor crack resistance. Furthermore, they have a high weight loss rate. The silane compound polymer of Comparative Example 2 has only phenyl groups as side chains. Therefore, the silane compound polymer of Comparative Example 2 has poor curability. The silane compound polymer of Comparative Example 3 has methyl groups instead of phenyl groups. Therefore, the silane compound polymer of Comparative Example 3 has poor crack resistance.

Claims

1. The following formula (a-1) and a repeating unit represented by the following formula (a-2): [R １ represents an unsubstituted aryl group having 6 to 12 carbon atoms, or a substituted aryl group having 6 to 12 carbon atoms.] and a silane compound polymer having a repeating unit represented by the following formula (repeating unit (2)):

2. The silane compound polymer according to claim 1, wherein the amount of the repeating unit (1) is 10 to 45 mol % based on the total amount of the repeating unit (1) and the repeating unit (2).

3. The silane compound polymer according to claim 1, wherein the total amount of the repeating units (1) and (2) is 70 to 100 mol % based on the total amount of repeating units in the silane compound polymer.

4. The silane compound polymer according to claim 1, having a mass average molecular weight (Mw) of 1,500 to 50,000.

5. The silane compound polymer according to claim 1, wherein the silane compound polymer is obtained by hydrolysis and polycondensation of an alkoxysilane compound and has a residual alkoxy group ratio of 2.0% or less.

6. When a curing evaluation test is conducted under the following conditions, the thickness reduction rate (X ｔ ) is 20% or less. [Curability Evaluation Test] A1: A 2 μm-thick film of the silane compound polymer is formed on a silicon wafer. A2: The film obtained in A1 above is heated at 250° C. for 1 minute to be cured. A3: The cured film obtained in A2 above is transferred to a 23° C. environment and left there until it cools to 23° C. A4: After A3 above, the cured film is immersed in diethylene glycol dimethyl ether at 23° C. for 10 minutes and dried on a hot plate heated to 150° C. for 1 minute. [In formula (F1), T １ represents the thickness of the silane compound polymer film before A4, and T ２ represents the thickness of the silane compound polymer film after A4.] 7. The silane compound polymer according to claim 1, which does not crack when subjected to a crack resistance evaluation test under the following conditions. [Crack Resistance Evaluation Test] B1: A 1 μm-thick film of the silane compound polymer is formed on a silicon wafer. B2: The film obtained in B1 is heated at 250° C. for 1 minute to be cured. B3: The cured film obtained in B2 is transferred to a 23° C. environment and left there until it cools to 23° C.

8. When thermogravimetry is performed under the following conditions, the weight loss rate (X) calculated by the following formula (F2) is ｍ The silane compound polymer according to claim 1, wherein the silane compound polymer has a % or less of SiO 2 (SiO 2 ) and a SiO 2 (SiO 2 ) content of SiO 2 is 7% or less. [Thermogravimetric Measurement] C1: The silane compound polymer is heated at 200°C for 120 minutes. C2: After C1, the silane compound polymer is heated to 500°C at a rate of 10°C / min. [In formula (F2), M １ represents the weight of the silane compound polymer before C1, and M ２ represents the weight of the silane compound polymer after C2.] 9. An insulating material for semiconductors comprising the silane compound polymer according to claim 1.

10. A semiconductor insulating film forming agent containing the silane compound polymer according to claim 1 and a solvent.

11. The semiconductor insulating film forming agent according to claim 10, wherein the solvent has a boiling point of 150° C. or higher.

12. The semiconductor insulating film forming agent according to claim 10, wherein the solvent is a polyether solvent.

13. The semiconductor insulating film forming agent according to claim 10, wherein the total amount of the silane compound polymer according to claim 1 and the solvent is 80 mass % or more of the total amount of the semiconductor insulating film forming agent.

14. The semiconductor insulating film forming agent according to claim 10, which is substantially free of reactive compounds other than the silane compound polymer according to claim 1.

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