JP6763136B2 - Organic-inorganic addition copolymer and silicon oxide film obtained by using it - Google Patents

Description

The present invention relates to an organic-inorganic addition copolymer, a method for producing a silicon oxide film using the same, and a silicon oxide film.

When a silicon oxide film is used as an insulating film or the like of a semiconductor device such as a thin film transistor (TFT), it is usually manufactured by chemical vapor deposition (CVD) or physical vapor deposition (PVD).
Film-forming technology using CVD and PVD has been accumulated for decades, and it is known that it is possible to form a reliable film with excellent properties such as insulation characteristics and gas barrier properties required for semiconductor devices. ..
In recent years, the size of the substrate has increased remarkably. However, CVD and PVD require a large-sized device, and further increasing the size of the device significantly increases the cost. Further, since CVD forms a film under high temperature conditions and PVD forms a film under vacuum conditions, it is disadvantageous for CVD and PVD to increase the size of the apparatus. In PVD, there is also a desire to avoid vacuum conditions if possible.
In addition, a silicon oxide film is also obtained by firing a silicon substrate at a high temperature and thermally oxidizing it. However, since heat close to 1000 ° C. is applied, a film forming method with a high energy load and high cost is used. is there. Further, the surface after film formation is rough, and for example, when the substrates are bonded to each other, chemical polishing is required, so that there is a problem that the number of steps is increased.

On the other hand, as the amount of data processing increases, electronic devices are required to have higher speed and higher functionality in data processing that cannot be handled by miniaturization alone. Therefore, attempts have been made to support data processing and add new functions by making the LSI three-dimensional (for example, Patent Document 1). In the manufacture of a three-dimensional LSI, a new element is formed on the interlayer insulating film, but at that time, the characteristics of the already completed element must be maintained. That is, a manufacturing process at a low temperature as much as possible while avoiding a high temperature is desired, including the formation of an interlayer film.

As a method for producing a silicon oxide film that does not use CVD or PVD, Patent Document 2 describes a substrate that transmits ultraviolet rays to be coated with a precursor such as dimethylsiloxane, silican, silicon alkoxide, silicate, and a polymer thereof, and the surface coated with the precursor. A method of forming a silica film by irradiating ultraviolet rays from the back surface side of the silicon film has been proposed.

Further, in Patent Document 3, a monomolecular film using a copolymer containing silsesquioxane containing one addition-polymerizable functional group and another addition-polymerizable monomer, and by accumulating these. A method has been proposed in which a obtained laminated film is produced and photodecomposition of an organic portion is caused by light irradiation to form Si—O having a network structure.

Further, Patent Document 4 proposes stainless steel coated with a plurality of silica-based films by using a sol-gel method.

Japanese Unexamined Patent Publication No. 2014-232863 Japanese Unexamined Patent Publication No. 2012-86990 JP-A-2009-114409 Japanese Unexamined Patent Publication No. 2004-291453

However, since the method disclosed in Patent Document 2 uses a precursor such as dimethylsiloxane, it takes time to convert to silicon oxide. Further, the method disclosed in Patent Document 3 is a very complicated method, and industrialization is not realistic. In addition, the sol-gel method requires a high-temperature process, which is not a simple method, and the substrates that can be used are limited. Further, when the coating film is fired, the residual silanol groups in the siloxane polymer are condensed, so that the film is liable to crack.
Therefore, there is a demand for a method for producing a silicon oxide film inexpensively and easily without using CVD or PVD.
In view of the above, it is an object of the present invention to provide a novel organic-inorganic addition copolymer capable of producing a silicon oxide film inexpensively and easily by using it. Another object of the present invention is to provide a novel organic-inorganic addition copolymer that can be used as a raw material for a high-quality silicon oxide film produced by CVD or PVD. Another object of the present invention is to provide a method for easily producing a high-quality silicon oxide film having the same level of quality as the silicon oxide film produced by CVD or PVD.

As a result of diligent studies, the present inventors can obtain a silicon oxide film inexpensively and easily by subjecting a coating film containing an organic-inorganic addition copolymer having a specific structure to UV / ozone treatment. We found that and came up with the present invention. Further, they have found that by using the organic-inorganic addition copolymer, a silicon oxide film having the same high quality as that obtained by CVD or PVD can be obtained, and the present invention has been conceived.

That is, the organic-inorganic addition copolymer according to the present invention is
[1] An addition copolymer containing a structural unit derived from the compound (A) represented by the formula (1) and a structural unit derived from the compound (B) represented by the formula (2).

式（１）においてＰｈはフェニル、Ａ^１は付加重合性官能基を有する基である。

In the formula (1), Ph is a phenyl group and A ¹ is a group having an addition-polymerizable functional group.

式（２）においてＲ^１は水素原子または炭素数が１から２０の直鎖状若しくは分枝鎖状のアルキルであり、該アルキルの炭素原子に結合している水素原子が水酸基に置き換えられていてもよく、炭素数が２以上の場合は任意のメチレンが酸素で置き換えられていてもよく、Ｒ^２は任意のメチレンが酸素で置き換えられていてもよい炭素数が１から２０の直鎖状又は分枝鎖状のアルキレン、Ｒ^３は炭素数が１から２０の直鎖状又は分枝鎖状のアルキルである。
［２］ Ａ^１が（メタ）アクリルを有するラジカル重合性官能基を有する基である、［１］に記載の付加共重合体。
［３］ 化合物（Ａ）が式（６）で表される化合物である、［１］に記載の付加共重合体。

In the formula (2), R ¹ is a hydrogen atom or a linear or branched-chain alkyl having 1 to 20 carbon atoms, and the hydrogen atom bonded to the carbon atom of the alkyl is replaced with a hydroxyl group. If the number of carbon atoms is 2 or more, any methylene may be replaced with oxygen, and R ² may be any methylene substituted with oxygen. A linear or linear atom having 1 to 20 carbon atoms. branched alkylene, R ³ is a straight-chain or branched alkyl having 1 to 20 carbon atoms.
[2] The addition copolymer according to [ 1 ] , wherein A ¹ is a group having a radically polymerizable functional group having (meth) acrylic.
[3] The addition copolymer according to [1], wherein the compound (A) is a compound represented by the formula (6).

［４］ 化合物（Ｂ）が、Ｎ−（ブトキシメチル）アクリルアミド、Ｎ−(メトキシメチ
ル)メタクリルアミド、Ｎ−（イソブトキシメチル）アクリルアミド及びＮ−（メトキシ
メチル）アクリルアミドから選択される、［１］乃至［３］のいずれかに記載の付加共重合体。
［５］ ［１］乃至［４］のいずれかに記載の付加共重合体と有機溶剤とを含む組成物。［６］ ［５］に記載の組成物を基板に塗布する工程、
前記工程により得られた被膜に紫外線を照射する工程、を含む、式（３）の構造を含有する酸化ケイ素膜の製造方法。

[4] Compound (B) is selected from N- (butoxymethyl) acrylamide, N- (methoxymethyl) methacrylamide, N- (isobutoxymethyl) acrylamide and N- (methoxymethyl) acrylamide, [1]. The addition copolymer according to any one of [3].
[5] A composition containing the addition copolymer according to any one of [1] to [4] and an organic solvent. [6] A step of applying the composition according to [5] to a substrate,
A method for producing a silicon oxide film containing the structure of the formula (3), which comprises a step of irradiating the film obtained by the above step with ultraviolet rays.

The organic-inorganic addition copolymer according to the present invention can be easily obtained by copolymerizing the compound (A) represented by the formula (1) and the compound (B) represented by the formula (2). Since it is soluble in various solvents, the composition can be applied to a general-purpose coating method such as spin coating and a film forming method such as printing. In the organic-inorganic addition copolymer according to the present invention, organic moieties such as phenyl group and acrylamide bonded to silsesquioxane are easily decomposed by UV / ozone treatment, so that they are converted to silicon oxide relatively quickly. To. Therefore, the silicon oxide film can be obtained inexpensively and easily.
Further, by using the organic-inorganic addition copolymer of the present invention, the temperature conditions are relatively mild and a simple process is performed without using an expensive apparatus, and the degree is equivalent to that obtained by CVD or PVD. It is possible to obtain a silicon oxide film having high quality and excellent abrasion resistance, high smoothness, and crack resistance.

It is an IR spectrum (on CaF ₂ ) before and after UV / ozone treatment of the coating film containing the organic-inorganic addition copolymer of the present invention. It is a continuous load scratch test result (on a silicon wafer) of an Example and a comparative example. It is a continuous load scratch test result (on a silicon wafer) of an Example.

Hereinafter, the present invention will be described in detail according to an embodiment. However, the present invention is not limited to the embodiments explicitly or implicitly described herein. In addition, all aspects of the present invention can be carried out in combination or alone.

The organic-inorganic addition copolymer of the present invention (hereinafter, also referred to as “copolymer of the present invention”) is a silsesquioxane containing an addition-polymerizable functional group which is the compound (A) represented by the formula (1). It is an addition copolymer containing a structural unit derived from it and a structural unit derived from acrylamide, which is the compound (B) represented by the formula (2).

式（１）においてＰｈはフェニル、Ａ^１は付加重合性官能基を有する基である。

In the formula (1), Ph is a phenyl group and A ¹ is a group having an addition-polymerizable functional group.

式（２）においてＲ^１は水素原子または炭素数が１から２０の直鎖状若しくは分枝鎖状のアルキルであり、該アルキルの炭素原子に結合している水素原子が水酸基に置き換えられていてもよく、炭素数が２以上の場合は任意のメチレンが酸素で置き換えられていてもよく、Ｒ^２は任意のメチレンが酸素で置き換えられていてもよい炭素数が１から２０の直鎖状又は分枝鎖状のアルキレン、Ｒ^３は炭素数が１から２０の直鎖状又は分枝鎖状のアルキルである。
本発明の共重合体はブロック共重合などの定序性共重合体であっても、ランダム共重合体であってもよいが、好ましくはランダム共重合体である。また、本発明の共重合体は架橋構造を有していたり、グラフト共重合体であってもよい。

In the formula (2), R ¹ is a hydrogen atom or a linear or branched-chain alkyl having 1 to 20 carbon atoms, and the hydrogen atom bonded to the carbon atom of the alkyl is replaced with a hydroxyl group. If the number of carbon atoms is 2 or more, any methylene may be replaced with oxygen, and R ² may be any methylene substituted with oxygen. A linear or linear atom having 1 to 20 carbon atoms. branched alkylene, R ³ is a straight-chain or branched alkyl having 1 to 20 carbon atoms.
The copolymer of the present invention may be a constitutive copolymer such as a block copolymer or a random copolymer, but is preferably a random copolymer. Further, the copolymer of the present invention may have a crosslinked structure or may be a graft copolymer.

Hereinafter, the compound (A) represented by the formula (1) will be described.

In the formula (1), Ph is a phenyl group and A ¹ is a group having an addition-polymerizable functional group.
Examples of addition polymerizable functional groups include groups having terminal olefin type or internal olefin type radically polymerizable functional groups; groups having cationically polymerizable functional groups such as vinyl ether and propenyl ether; and vinyl carboxyl, cyanoacryloyl and the like. A group having an anionic polymerizable functional group is included, and a radical polymerizable functional group is preferable.

The above radically polymerizable functional group is not particularly limited as long as it is a radically polymerizable group, for example, methacryloyl, acryloyl, allyl, styryl, α-methylstyryl, vinyl, vinyl ether, vinyl ester, acrylamide, methacrylicamide, N-. Includes vinyl amides, maleic acid esters, fumaric acid esters, N-substituted maleimides, etc., among others (
Meta) Acrylic or styryl-containing groups are preferred. Here, (meth) acrylic is a general term for acrylic and methacrylic, and means acrylic and / or methacrylic. The same shall apply hereinafter.

Examples of the above-mentioned radically polymerizable functional group having (meth) acrylic include a group represented by the following formula (4).
In the formula (4), Y ¹ represents an alkylene having 2 to 10 carbon atoms, preferably 2 to 2 carbon atoms.
It shows alkylene of 6, and more preferably alkylene (propylene) having 3 carbon atoms. Further, R ⁴ represents a hydrogen atom, an alkyl having 1 to 5 carbon atoms, or an aryl having 6 to 10 carbon atoms, preferably a hydrogen atom or an alkyl having 1 to 3 carbon atoms, and particularly preferably a hydrogen atom or methyl. is there. Further, any hydrogen atom may be replaced with an alkyl having 1 to 5 carbon atoms.

Further, examples of the above-mentioned radically polymerizable functional group having styryl include a group represented by the following formula (5). In formula (5), Y ² represents a single bond or an alkylene having 1 to 10 carbon atoms, preferably a single bond or an alkylene having 1 to 6 carbon atoms, and more preferably a single bond or an alkylene having 1 or 2 carbon atoms. It is particularly preferably a single bond or an alkylene (ethylene) having 2 carbon atoms. Further, vinyl is bonded to any carbon of the benzene ring, and is preferably bonded to a carbon atom at the para position with respect to Y ² .

As the compound (A) represented by the formula (1) having such an addition-polymerizable functional group, 3- (3,5,7,9,11,13,15-heptaphenylpentaciclo [9] represented by the formula (6). 5.1.113, 9.15, 15.17, 13] octasiloxan-1-yl) Compound polymerization. From the viewpoint of the reactivity of radical polymerization, the solubility and storage stability of the organic-inorganic addition copolymer in a solvent, the speed of silicon oxide (SiO ₂ ) conversion in UV / ozone treatment, and the characteristics of the formed silicon oxide film, the formula The silsesquioxane represented by (6) is particularly preferable.

The compound (A) represented by the formula (1) can be synthesized, for example, according to the method described in JP-A-2004-123698. That is, the silsesquioxane compound having a (meth) acrylic group as an addition polymerizable functional group can be synthesized by the method described in Example 3 of JP-A-2004-123698, and a styryl group is used as the addition polymerizable functional group. The silsesquioxane compound contained therein can be obtained by reacting the compound of Example 2 (1-1) of Japanese Patent Application Laid-Open No. 2004-123698 with vinylphenyltrichlorosilane or vinylphenylalkyltrichlorosilane.

Hereinafter, the compound (B) represented by the formula (2) will be described.

式（２）においてＲ^１は水素原子または炭素数が１から２０の直鎖状又は分枝鎖状のアルキルであり、該アルキルの炭素原子に結合している水素原子が水酸基に置き換えられていてもよく、炭素数が２以上の場合は任意のメチレンが酸素で置き換えられていてもよく、Ｒ^２は任意のメチレンが酸素で置き換えられていてもよい炭素数が１から２０の直鎖状又は分枝鎖状のアルキレン、Ｒ^３は炭素数が１から２０の直鎖状又は分枝鎖状のアルキルである。
アルキレンとは、アルカンから水素原子を２つ取り除いた２価の置換基であり、−Ｃ_ｎＨ_2ｎ−で表される。任意のメチレンが酸素で置き換えられていてもよい炭素数１〜２０
のメチレン、エチレン、ｎ−プロピレン、ｎ−ブチレン、ｎ−ヘキシレン、ｎ−ヘプチレン、ｎ−オクチレン、ｎ−ドデシレンなどである。なお、Ｒ²は直鎖状及び分枝鎖状のい
ずれであってもよい。また、分枝鎖状の場合、分枝鎖の炭素も炭素数に含めるものとする。
アルキルとは、アルカンの末端から水素原子を1つ取り除いた官能基で、Ｃ_ｎＨ_{２ｎ＋
１}で表される。Ｒ³は直鎖状及び分枝鎖状のアルキルのいずれであってもよい。なお、分
枝鎖状の場合、分枝鎖の炭素も炭素数に含めるものとする。炭素数が１から２０のアルキルとは、具体的には、メチル、エチル、プロピル、１−メチルエチル、ブチル、２−メチルプロピル、１，１−ジメチルエチル、ペンチル、ヘキシル、１，１，２−トリメチルプロピル、ヘプチル、オクチル、２，４，４−トリメチルペンチル、ノニル、デシル、ウンデシル、ドデシル、テトラデシル、ヘキサデシル、オクタデシル、エイコシル、３−メトキシプロピルが挙げられる。
共重合反応における、モノマーの反応性の観点から、Ｒ^１は水素原子又はメチルが好ましい。Ｒ²はメチレン、エチレン、又はプロピレンが好ましい。Ｒ³はメチル、エチル、プロピル、イソプロピル、ブチル、イソブチルが好ましい。

In the formula (2), R ¹ is a hydrogen atom or a linear or branched-chain alkyl having 1 to 20 carbon atoms, and the hydrogen atom bonded to the carbon atom of the alkyl is replaced with a hydroxyl group. If the number of carbon atoms is 2 or more, any methylene may be replaced with oxygen, and R ² may be any methylene substituted with oxygen. A linear or linear atom having 1 to 20 carbon atoms. branched alkylene, R ³ is a straight-chain or branched alkyl having 1 to 20 carbon atoms.
The alkylene is a divalent substituent obtained by removing two hydrogen atoms from an alkane, and is represented by −C _n H _2n −. Any methylene may be replaced with oxygen 1-20 carbon atoms
Methylene, ethylene, n-propylene, n-butylene, n-hexylene, n-heptylene, n-octylene, n-dodecylene and the like. In addition, R ² may be either linear or branched chain. In the case of a branched chain, the carbon of the branched chain is also included in the number of carbon atoms.
Alkyl is a functional group obtained by removing one hydrogen atom from the end of an alkane, and C _n H _{2n +.}
It is represented by ₁ . R ³ may be either a straight chain or a branched chain alkyl. In the case of a branched chain, the carbon of the branched chain is also included in the number of carbon atoms. The alkyl having 1 to 20 carbon atoms is specifically methyl, ethyl, propyl, 1-methylethyl, butyl, 2-methylpropyl, 1,1-dimethylethyl, pentyl, hexyl, 1,1,2. Included are −trimethylpropyl, heptyl, octyl, 2,4,4-trimethylpentyl, nonyl, decyl, undecyl, dodecyl, tetradecyl, hexadecyl, octadecyl, eicosyl and 3-methoxypropyl.
From the viewpoint of monomer reactivity in the copolymerization reaction, R ¹ is preferably a hydrogen atom or methyl. R ² is preferably methylene, ethylene, or propylene. R ³ is preferably methyl, ethyl, propyl, isopropyl, butyl and isobutyl.

The compound (B) represented by the formula (2) is selected from the viewpoints of solubility of the produced copolymer in a solvent, wettability when the prepared composition is applied to a substrate, and decomposition rate in UV / ozone treatment. , N- (butoxymethyl) acrylamide represented by the formula (7), N- (methoxymethyl) methacrylamide, N- (isobutoxymethyl) acrylamide, N- (methoxymethyl) acrylamide and the like are particularly preferable.

The compound (B) represented by the formula (2) may be synthesized or a commercially available product may be obtained and used. By using a mass-produced commercial product, there is an advantage of cost reduction.
Commercially available products include, for example, N- (butoxymethyl) acrylamide manufactured by Tokyo Chemical Industry Co., Ltd., N- (methoxymethyl) methacrylamide, N- (isobutoxymethyl) acrylamide manufactured by MRC Unitech Co., Ltd., and N- (methoxymethyl). Acrylamide, for example.

<Organic-inorganic addition copolymer>
The organic-inorganic addition copolymer of the present invention contains silsesquioxane containing an addition-polymerizable functional group, which is the compound (A) represented by the formula (1), and acrylamide, which is the compound (B) represented by the formula (2). It is obtained by polymerizing and.
The weight ratio of the compound represented by the general formula (A) to the compound represented by the general formula (B) may be appropriately determined according to the target polymer, but 99.99: 0.01 to 0. It is preferably 01: 99.99, and more preferably 95.0: 5.00 to 10.00: 90.00. As the ratio of (A) increases, the silicon oxide film can be formed thicker by one film formation by UV / ozone treatment after application.
On the other hand, when the ratio of (B) is increased, the solubility in various solvents is improved. The increased choice of solvents that can be used facilitates wettability and viscosity adjustment. Therefore, it is possible to form a coating film on various substrates, and it is also possible to carry out various film forming methods.
Further, the weight average molecular weight of the copolymer is preferably 5,000 to 200,000, more preferably 5,000 to 100,000. When the molecular weight is low, the solubility in various solvents is excellent, so that the wettability can be easily adjusted when applied to various substrates. In the case of a high molecular weight, the film after coating and the silicon oxide film after UV / ozone treatment are excellent in in-plane uniformity, surface smoothness, etc., and are highly flat even when the substrate surface has slight irregularities. Can be converted.
As described above, the copolymer of the present invention may be a constitutive copolymer such as a block copolymer or a random copolymer, but is preferably a random copolymer. Further, the copolymer of the present invention may have a crosslinked structure or may be a graft copolymer.

<Polymerization method>
Hereinafter, a method for producing an addition copolymer containing a structural unit derived from the compound (A) represented by the formula (1) and a structural unit derived from the compound (B) represented by the formula (2) will be described.
Polymerization can be carried out using a polymerization initiator.
Examples of polymerization initiators are dimethyl 2,2'-azobis (2-methylpropionate), 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis (2,4-azo). Azo compounds such as dimethylvaleronitrile), 2,2'-azobis (2-butyronitrile), dimethyl-2,2'-azobisisobutyrate, 1,1'-azobis (cyclohexane-1-carbonitrile); benzoyl Peroxide, lauryl peroxide, octanoyl peroxide, acetyl peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, t-butylperoxyacetate, t-butylperoxybenzoate, Includes radical polymerization initiators such as peroxides such as t-butylperoxyneodecanoate; and dithiocarbamate such as tetraethylthiuram disulfide;

Further, examples of the polymerization initiator include a living radical polymerization initiator, a photopolymerization initiator and the like.
Living radical polymerization is represented by atom transfer radical polymerization; reversible addition cleavage chain transfer; iodine transfer polymerization; inifata polymerization, and can be carried out using the polymerization initiators described in Documents A to C below.
-Reference A: Mikiharu Kamachi, supervised by Tsuyoshi Endo, Radical Polymerization Handbook, published on August 10, 1999, published by NTS).
・ Reference B: HANDBOOK OF RADICAL POLYMERIZATION, K. Matyjaszewski, TP Davis, Eds., John Wiley and Sons, Canada 2002
-Reference C: Japanese Unexamined Patent Publication No. 2005-105265

Photopolymerization can be carried out by using the compound described in Document D (Photopolymer Association, Photosensitive Material List Book, March 31, 1996, published by Bunshin Publishing) as a photopolymerization initiator.
Specific examples of the photopolymerization initiator are not particularly limited as long as they are compounds that generate radicals by irradiation with ultraviolet rays or visible light. Compounds used as photopolymerization initiators include benzophenone, Michler's ketone, 4,4'-bis (diethylamino) benzophenone, xanthone, thioxanthone, isopropylxanthone, 2,4-diethylthioxanthone, 2-ethylanthraquinone, acetophenone, 2-hydroxy. -2-Methylpropiophenone, 2-Hydroxy-2-methyl-4'-isopropylpropiophenone, 1-hydroxycyclohexylphenylketone, isopropylbenzoin ether, isobutylbenzoin ether, 2,2-diethoxyacetophenone, 2,2 -Dimethoxy-2-phenylacetophenone, camphorquinone, benzanthron, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one, 2-benzyl-2-dimethylamino-1-( 4-Molholinophenyl) -butanone-ethyl 1,4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, 4,4'-di (t-butylperoxycarbonyl) benzophenone, 3,4,4'-tri ( t-Butylperoxycarbonyl) benzophenone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2- (4'-methoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (3') , 4'-dimethoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (2', 4'-dimethoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2 -(2'-methoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4'-pentyloxystyryl) -4,6-bis (
Trichloromethyl) -s-triazine, 4- [p-N, N-di (ethoxycarbonylmethyl)] -2,6-di (trichloromethyl) -s-triazine, 1,3-bis (trichloromethyl) -5 ---
(2'-Chlorophenyl) -s-triazine, 1,3-bis (trichloromethyl) -5- (4'-methoxyphenyl) -s-triazine, 2- (p-dimethylaminostyryl) benzoxazole, 2-( p-Dimethylaminostyryl) benzthiazole, 2-mercaptobenzothiazole, 3,3'-carbonylbis (7-diethylaminocoumarin), 2- (o-chlorophenyl) -4,4', 5,5'-tetraphenyl- 1,2'-biimidazole, 2,2'-bis (2-
Chlorophenyl) -4,4', 5,5'-Tetrakis (4-ethoxycarbonylphenyl) -1,2'-biimidazole, 2,2'-bis (2,4-dichlorophenyl) -4,4', 5 , 5'-Tetraphenyl-1,2'-biimidazole, 2,2'-bis (2,4-dibromophenyl) -4,4
′, 5,5′-Tetraphenyl-1,2′-biimidazole, 2,2′-bis (2,4,6-trichlorophenyl) -4,4′,5,5′-tetraphenyl-1, 2'-biimidazole, 3- (2-methyl-2-dimethylaminopropionyl) carbazole, 3,6-bis (2-methyl-2-morpholinopropionyl) -9-n-dodecylcarbazole, 1-hydroxycyclohexylphenylketone , Bis (η5-2,4-cyclopentadiene-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole-1-yl) -phenyl) titanium, and the like. These compounds may be used alone, or a mixture of two or more thereof may be used. 3,3', 4,4'-Tetra (t-Butyl Peroxycarbonyl) Benzophenone, 3,3', 4,4'-Tetra (
t-hexylperoxycarbonyl) benzophenone, 3,3'-di (methoxycarbonyl) -4,4'-di (t-butylperoxycarbonyl) benzophenone, 3,4'-di (methoxycarbonyl) -4,3'- Di (t-butylperoxycarbonyl) benzophenone, 4,4
′ -Di (methoxycarbonyl) -3,3'-di (t-butylperoxycarbonyl) benzophenone and the like are preferred.

The amount of the polymerization initiator used in the polymerization may be 0.01 to 10 mol% with respect to the total number of moles of the monomer.

Further, a chain transfer agent may be used in the polymerization. By using a chain transfer agent, the molecular weight can be appropriately controlled. Examples of chain transfer agents include thio-β-naphthol, thiophenol, n-butyl mercaptan, ethyl thioglycolate, mercaptoethanol, mercaptoacetic acid, isopropyl mercaptan, t-butyl mercaptan, dodecanethiol, thiophosphate, pentaerythritol tetra. Mercaptans such as (3-mercaptopropionate), pentaerythritol tetra (3-mercaptoacetate); disulfides such as diphenyldisulfide, diethyldithioglycolate, diethyldisulfide; etc., as well as toluene, methylisobutyl, etc. Rate, carbon tetrachloride, isopropylbenzene, diethyl ketone, chloroform, ethylbenzene, butyl chloride, s-butyl alcohol, methyl ethyl ketone, methyl isobutyl ketone, propylene chloride, methyl chloroform, t-butyl benzene, n-butyl alcohol, isobutyl alcohol, acetic acid , Ethyl acetate, acetone, dioxane, ethane tetrachloride, chlorobenzene, methylcyclohexane, t-butyl alcohol, benzene and the like.
The chain transfer agent is preferably a mercaptan. In particular, mercaptoacetic acid can lower the molecular weight of the polymer to make the molecular weight distribution uniform. The chain transfer agent can be used alone or in admixture of two or more.

The specific method for producing the copolymer of the present invention may be the same as the method for producing an ordinary addition copolymer. For example, a solution polymerization method, an emulsion polymerization method, a suspension polymerization method, a lumpy polymerization method, or a lumpy state. -A suspension polymerization method or a polymerization method using supercritical CO ₂ can be used.
In the case of the solution polymerization method, the compound (A) represented by the formula (1), the compound (B) represented by the formula (2), the polymerization initiator, the chain transfer agent and the like are dissolved in an appropriate solvent. Then, it may be heated or irradiated with light to cause an addition polymerization reaction.

Examples of solvents used in the polymerization reaction include hydrocarbon solvents (benzene, toluene, etc.), ether solvents (diethyl ether, tetrahydrofuran (THF), 2-methyl tetrahydrofuran, diphenyl ether, anisole, dimethoxybenzene, cyclopentyl methyl ether (diethyl ether, tetrahydrofuran (THF)) CPME), etc.), halogenated hydrocarbon solvents (methylene chloride, chloroform, chlorobenzene, etc.), ketone solvents (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), alcohol solvents (methanol, ethanol, propanol, isopropanol, n-butyl) Alcohol, t-butyl alcohol, etc.), nitrile solvent (acetoyl, propionitrile, benzonitrile, etc.), ester solvent (ethyl acetate, butyl acetate, etc.), carbonate solvent (ethylene carbonate, propylene carbonate, etc.), amide solvent Solvents (N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone), hydrochlorofluorocarbon solvents (HCFC-141b, HCFC-225), hydrofluorocarbon (HFCs) solvents (2-4 carbon atoms) 5, 6 or more HFCs), perfluorocarbon solvent (perfluoropentane, perfluorohexane), alicyclic hydrofluorocarbon solvent (fluorocyclopentane, fluorocyclobutane), oxygen-containing fluorosolvent (fluoroether, fluoropoly) Ether, fluoroketone, fluoroalcohol), aromatic fluorine solvent (α,
α, α-trifluorotoluene, hexafluorobenzene) and water are included. These may be used alone or in combination of two or more.
The amount of the solvent used may be an amount such that the total concentration of the monomer is 5 to 80% by mass.
The reaction temperature is not particularly limited and may be 0 to 200 ° C. as a guide, preferably room temperature to 150 ° C. The polymerization reaction can be carried out under reduced pressure, normal pressure or pressure depending on the type of monomer and the type of solvent.

The polymerization reaction is preferably carried out in an atmosphere of an inert gas such as nitrogen or argon. This is to prevent the generated radicals from coming into contact with oxygen and inactivating them to reduce the polymerization rate, and to obtain a polymer having an appropriately controlled molecular weight. Further, the polymerization reaction is preferably carried out in a polymerization system in which dissolved oxygen is removed under reduced pressure (the polymerization reaction may be carried out as it is under reduced pressure after removing dissolved oxygen under reduced pressure).

The polymer obtained in the solution may be purified or isolated by a conventional method, or the solution may be used as it is for forming a coating film or the like.

<Composition>
The copolymer of the present invention can be made into a composition by dissolving it in a solvent. A general-purpose coating method such as spin coating or various printing methods can be applied to such a composition, and by using this composition as a coating agent, a silicon oxide film can be produced inexpensively and easily. As described above, the polymer obtained in the solution may be purified or isolated by a conventional method and then dissolved in a solvent to form a composition, or the solution as it is may be used as a composition for forming a coating film. May be good.

<Solvent>
As a solvent for a composition containing an addition copolymer containing a structural unit derived from the compound (A) represented by the formula (1) and a structural unit derived from the compound (B) represented by the formula (2), and a solvent. Is not particularly limited as long as the copolymer of the present invention can be dissolved. Preferred solvents include the same solvents as those used for polymerization. For example, hydrocarbon solvents (benzene, toluene, etc.), ether solvents (diethyl ether, tetrahydrofuran (THF), 2-methyl tetrahydrofuran, diphenyl ether, anisole, dimethoxybenzene, cyclopentylmethyl ether (CPME), etc.), halogenated hydrocarbons. System solvents (methylene chloride, chloroform, chlorobenzene, etc.), ketone solvents (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), alcohol solvents (methanol, ethanol, propanol, isopropanol, n-butyl alcohol, t-butyl alcohol, etc.), Nitrile-based solvents (acetoyl, propionitrile, benzonitrile, etc.), ester-based solvents (ethyl acetate, butyl acetate, etc.), carbonate-based solvents (ethylene carbonate, propylene carbonate, etc.), amide-based solvents (N, N-dimethylformamide, etc. N, N-dimethylacetamide, N-methylpyrrolidone), hydrochlorofluorocarbon-based solvent (HCFC-141b, HCFC-225), hydrofluorocarbon (HFCs) -based solvent (HFCs having 2 to 4, 5 and 6 or more carbon atoms), Perfluorocarbon solvent (perfluoropentane, perfluorohexane), alicyclic hydrofluorocarbon solvent (fluorocyclopentane, fluorocyclobutane), oxygen-containing fluorosolvent (fluoroether, fluoropolyether, fluoroketone, fluoroalcohol), Aromatic fluorosolvents (α, α, α-trifluorotoluene, hexafluorobenzene) and water are included. These may be used alone or in combination of two or more.

<Method of preparing composition>
The method for preparing the composition is not particularly limited, and various methods can be used for preparation. The addition copolymer and the solvent may be mixed and prepared immediately before coating, or the mixed and adjusted composition may be stored and used.
Various additives may be used for the coating agent of the present invention depending on the purpose. As the additive, a surfactant or a silane coupling agent can be used.
Commercially available fluorine-based surfactants include Futtergent 710FS, Futtergent 730FL, Futtergent 730LM, Futtergent 601AD (trade name: Neos Co., Ltd.), Megafuck F-552, Megafuck F-555, Mega Fvck F-558
, Mega Fvck F-561, Mega Fvck F-562, Mega Fvck F-568, Mega Fvck F-571, Mega Fvck RS-72K, Mega Fvck RS-75, Mega Fvck RS-76-E, Mega Fvck RS-76 -NS, Megafvck RS-90 (trade name: manufactured by DIC Co., Ltd.) can be mentioned.
Commercially available Si-based surfactants include BYK300, BYK306, BYK310, BYK320, BYK330, BYK342, BYK344, BYK346, BYK UV.
3500 and BYK UV 3570 (trade name: manufactured by Big Chemie Japan Co., Ltd.), TEGO Glide 410, TEGO Glide 440, TEGO Glide 450, TEGO Rad 2200N, TEGO Rad 2250, TEGO Rad 2300 (trade name: Evonik Degussa) ) Made).
The content of the surfactant is preferably 0.01 to 20 parts by mass, more preferably 0.05 to 10 parts by mass, and further preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the solid content of the composition. is there. When the content of the surfactant is within the above range, the wettability, leveling property, and film surface uniformity with respect to the substrate and the like are improved.
The silane coupling agent is not particularly limited, and a known coupling agent can be used, and it is preferable to use a silane coupling agent. Examples of silane coupling agents include trialkoxysilane compounds and dialkoxysilane compounds.
Examples of the trialkoxysilane compound or dialkoxysilane compound include γ-vinylpropyltrimethoxysilane, γ-vinylpropyltriethoxysilane, γ-acryloylpropylmethyldimethoxysilane, γ-acryloylpropyltrimethoxysilane, and γ-acryloylpropylmethyldi. Ethoxysilane, γ-acryloylpropyltriethoxysilane, γ-methacryloylpropylmethyldimethoxysilane, γ-methacryloylpropyltrimethoxysilane, γ-methacryloylpropylmethyldiethoxysilane, γ-methacryloylpropyltriethoxysilane, γ-aminopropylmethyldimethoxy Silane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-aminopropyltriethoxysilane, N-aminoethyl-γ-iminopropylmethyldimethoxysilane, N-aminoethyl-γ-aminopropyltri Methoxysilane, N-aminoethyl-γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropylmethyldimethoxy Silane, N-phenyl-γ-aminopropylmethyldiethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropylmethyldiethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ- Isocyanatopropylmethyldiethoxysilane, γ-isocyanatopropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ- Examples thereof include glycidoxypropyltriethoxysilane and 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane.
Only one kind of silane coupling agent may be used, or two or more kinds may be used.
When the coupling agent is contained in the composition of the present invention, the concentration of the coupling agent in the composition is 0.01 to 10% by weight of the solid content of the composition of the present invention.

<Physical properties of composition>
The composition according to the present invention preferably contains the copolymer of the present invention in an amount of 1 part by mass to 90 parts by mass, more preferably 3 parts by mass to 50 parts by mass, based on 100 parts by mass of the solvent. It is more preferable to include 5 parts by mass to 30 parts by mass.
Within this range, the viscosity can be easily applied. The range is 1 to 1000 mPa · s (pascal second). For example, when coating on a glass substrate is performed by a spin coating method, 1 to 500 mPa · s is preferable. Apply once by screen printing method and film thickness 5
In order to obtain 0 to 500 nm, 1 to 500 mPa · s is preferable. When the blade coater method, the die coater method, or the like is used, 1 to 500 mPa · s is preferable.

<Film formation>
Hereinafter, film formation on a substrate using the above composition will be described.
Examples of the film forming method include a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a wire bar coating method, a blade coating method, a roller coating method, an air knife coating method, a curtain coating method, etc. It is also possible to use a known coating method of. In this method, spin coating and coating by a printing method are most suitable from the viewpoint of being suitable for large-scale industrial production.
The film thickness of the composition applied on the substrate is 5 nm or more and 10 μm or less, preferably 5 nm or more and 2 μm or less.
In the present invention, it is preferable to go through a step of removing the solvent after coating. The method for removing the solvent is not particularly limited, but it is preferably carried out by evaporating the solvent. Examples of the method for evaporating the solvent include methods such as heating, depressurization, and ventilation. Above all, from the viewpoint of production efficiency and handleability, it is preferable to evaporate the solvent by heating, and it is more preferable to evaporate the solvent by heating while ventilating. Specifically, pre-drying is performed at 50 to 100 ° C. for 10 minutes to 2 hours, firing is performed at 50 to 100 ° C. and higher than the pre-drying for 10 minutes to 2 hours, and heat treatment is performed at 80 to 150 ° C. for 10 minutes to 30 minutes. It is preferable to perform.

<Board>
The composition of the present invention can be siliconized at room temperature, and is carried out under temperature conditions of up to about 150 ° C., usually within 100 ° C., throughout the process up to the formation of the silicon oxide film. Therefore, the substrate on which the composition according to the present invention is applied is not particularly limited as long as it has a heat resistance of about 150 ° C. to about 100 ° C. For example, quartz substrate, glass substrate such as barium borosilicate glass, aluminum borosilicate glass, calcium fluoride substrate, ceramic substrate including metal oxide substrate, polycarbonate (PC) film, silicone film, polyethylene terephthalate (PET) film. , Polyethylene naphthalate (PEN) film, cycloolefin polymer (COP) film, polypropylene film, polyethylene film, acrylic polymer film, polyvinyl alcohol film, triacetyl cellulose film, polyimide (PI) film, plastic film such as liquid crystal polymer film, A carbon fiber film, a semiconductor substrate such as a silicon wafer, a SUS substrate, a metal substrate such as a copper substrate, or the like can be used.
As will be described later, the silicon oxide film obtained by applying and curing the composition according to the present invention and then curing is excellent in abrasion resistance, film surface smoothness, film density, and crack resistance. Therefore, it can be suitably used for a flexible substrate.

<UV / ozone treatment>
In the present invention, after film formation, UV / ozone treatment of irradiating ultraviolet rays as active energy rays in an atmospheric atmosphere containing oxygen is performed to convert the coating film into a silicon oxide thin film. That is, ozone and atomic oxygen obtained by irradiation with ultraviolet rays are used to convert the coating film into a silicon oxide thin film.
That is, in the present invention, a silicon oxide film containing the structure of the formula (3) is produced by including a step of applying the composition to the substrate and a step of irradiating the coating film obtained by the above step with ultraviolet rays. be able to.

The wavelength of the ultraviolet rays to be irradiated is not particularly limited as long as ozone can be generated. Ultraviolet rays with a wavelength of about 185 nm decompose oxygen molecules to generate oxygen atoms. Furthermore, oxygen atoms combine with O ₂ (oxygen molecules) in the atmosphere to generate O ₃ (ozone). As the light source, a deuterium lamp, a xenon lamp, a metal halide lamp, an excimer lamp, a mercury lamp, or the like, as well as an excimer laser or the like can be used. Among them, the low-pressure mercury lamp is preferable because it emits ultraviolet rays of 185 nm and 254 nm and can further reduce the manufacturing cost.
The temperature and atmosphere at the time of ultraviolet irradiation are carried out from room temperature of about 25 ° C. to the heat resistant temperature of the substrate, can be carried out in an air atmosphere, and are preferably carried out in the range of 10 ³ to ⁶ Pa. When the temperature of the substrate and the coating film rises above the assumed temperature due to the irradiation with ultraviolet rays, the inside of the apparatus may be allowed to cool for an arbitrary time, and then the irradiation with ultraviolet rays may be resumed.
The irradiation time is about 3 minutes to 3 hours.
A commercially available device can be used for the UV / ozone treatment. Further, cut filters may be installed on the coated surface at arbitrary intervals.
Air or oxygen may be delivered into the device at any rate.
As described above, as the method for producing a silicon oxide film according to an embodiment of the present invention, a commercially available device can be used, and the film can be produced inexpensively and easily in a short time under low temperature conditions. Moreover, a high quality silicon oxide film can be obtained.
Irradiation is usually performed from the coated surface side, but UV irradiation can also be performed from the back surface side of the coated surface by using a substrate capable of transmitting ultraviolet rays.

<Silicon oxide film>
The siliconization of the coating film can be confirmed by IR measurement as shown in Examples. Specifically, the peak derived from the organic group of the copolymer of the present invention disappears, and in the absorption near 800 to 1300 cm ^-1 , SiO _3/2 decreases and SiO _4/2 increases. It can be confirmed that silicon oxide has been formed.
The silicon oxide film obtained by UV / ozone treatment of the copolymer of the present invention is presumed to have a very uniform crystal structure as represented by the formula (3), and has a thin film of about 5 nm to 300 nm. It is possible to have excellent properties such as adhesion, scratch resistance, and surface smoothness.
The pencil hardness of the silicon oxide film obtained by the present invention by a pencil hardness tester can be 2H or more and 6H or less on a silicon wafer and 2H or more and 6H or less on a glass substrate. Preferably, it is 4H or more and 6H or less on a silicon wafer, and 4H or more and 6H or less on a glass substrate. By setting the hardness and thickness of the silicon oxide film within this range, it is possible to achieve both scratch resistance and flexibility.
Further, the silicon oxide film obtained by the present invention has high adhesion to the substrate, and the peeling rate by the cross-cut test can be less than 10% on the silicon wafer and less than 10% on the glass. Preferably, the peeling is 0% on the silicon wafer and 0% on the glass.
The light transmittance of the silicon oxide film obtained by the present invention by an ultraviolet-visible spectrophotometer may be 80% or more on a CaF ₂ substrate (220 to 800 nm) and 80% or more on a glass substrate (400 to 800 nm). it can. Preferably, it is 90% or more on the CaF ₂ substrate (220 to 800 nm) and 90% or more on the glass substrate (400 to 800 nm).
The silicon oxide film obtained by the present invention can have scratch resistance. From this, it is presumed that the silicon oxide film obtained by the present invention is likely to undergo stress relaxation. In addition, it can have crack resistance.
The silicon oxide film obtained by the present invention has excellent slipperiness. Specifically, the frictional force by the constant load measurement (slipperiness) test can achieve a dynamic friction coefficient of less than 0.10 μk and a static friction coefficient of 0.10 or less, as shown in Examples described later. The silicon oxide film obtained by the present invention having such characteristics can be suitably used for a flexible substrate regardless of the substrate.
Further, the silicon oxide film obtained by the present invention can have surface smoothness, and when the surface roughness is measured using a light interference roughness meter, Ra has a smooth surface of about 0.4 nm. it can.
The silicon oxide film obtained by the present invention can have a film density of 1.7 to 2.1 g / cm ³ .
Due to these characteristics, the silicon oxide film obtained by the present invention and the silicon oxide film obtained by a conventional method such as thermal oxidation of a silicon substrate have different hardness and state between the surface and the inside, and a new silicon oxide film can be obtained. It is presumed that it is formed.

The present invention will be described in more detail based on examples. The present invention is not limited to the following examples.

<Measuring equipment and method>
The copolymer (A) of the present invention was measured by gel permeation chromatography (GPC) method by number average molecular weight and weight average molecular weight. Specifically, the copolymer is diluted with tetrahydrofuran (THF) so that the concentration of the copolymer is about 0.05 to 0.10% by mass, and columns KF-805L and KF-804L manufactured by Showa Denko Co., Ltd. are arranged in this order. It was determined by using THF in series as a developing agent and measuring by gel permeation chromatography (GPC) method, using polystyrene as a standard substance, and converting from this.

<Production example of compound (1)>
The compound (A) silsesquioxane (SQ) having a methacryloyl group, which is a comonomer of the copolymer (I) of the present invention, was synthesized by the method described in Example 3 of JP-A-2004-123698. A compound represented by the formula (6) (hereinafter referred to as SQ) was used.

<Polymerization example>
Production of copolymer (I)

N- (butoxymethyl) acrylamide (hereinafter referred to as NBMA) (2.09 g) and SQ (7.00 g) manufactured by Tokyo Chemical Industry Co., Ltd., which are comonomer, are charged into a four-necked flask with a stirrer and used as a solvent. Toluene / ethyl acetate (26.2 g, mass ratio 1: 1) was added as a mixture, and the mixture was heated and stirred at 80 ° C. to dissolve the comonomer.
Polymerization was initiated by dissolving 0.046 g of dimethyl 2,2'-azobis (2-methylpropionate) as a polymerization initiator in toluene (1.1 g) and adding it into a flask using a syringe. The polymerization was carried out at 80 ° C. for 7 hours, cooled to room temperature, and then the polymerization solution was added dropwise to an ethyl acetate / methanol mixed solvent (mass ratio 1: 1) to perform reprecipitation purification.
The precipitate was filtered under reduced pressure, and the obtained filtered product was dried under reduced pressure at 80 ° C. for 5 hours to obtain a copolymer (I).
When the copolymer (I) was analyzed by GPC, the weight average molecular weight (Mw) was 63,000. Further, when ¹ H-NMR measurement was performed on the copolymer (I) and the proton numbers of SQ and NBMA were compared, it was found that the introduction rate of SQ in the copolymer was 30 mol%.

<Film formation>
1.0 g of the copolymer (I) was placed in a glass sample bottle, toluene was added to make 10.0 g, and the mixture was stirred on a hot stirrer set at about 80 ° C. until it melted. After returning to room temperature, the mixture was filtered through a PTFE syringe filter having a pore size of 0.2 to 0.45 μm to prepare a composition containing the copolymer of the present invention.
A circular CaF ₂ substrate having a diameter of 3 cm was set on a sample table of a spin coater, and a sufficient amount of the composition was dropped onto the CaF ₂ substrate so as to spread over the entire CaF ₂ substrate, and spin coating was immediately performed. The CaF ₂ substrate on which the film was formed was fired on a hot plate preheated to 65 ° C. for 20 minutes, then at 85 ° C. for 20 minutes, and finally at 120 ° C. for 30 minutes. When the film thickness of the obtained coating film was measured with a contact-type profilometer, the film thickness was 800 nm.

<UV / ozone irradiation on the coating film>
The switch was turned on 30 minutes before using the UV lamp in advance, the sample table of the UV cleaning surface modifier ASM2001N manufactured by Asumi Giken Co., Ltd. was set at an irradiation distance of 1 cm, and the substrates on which the coating film was formed were arranged. Further, a low wavelength cut filter was installed so as not to come into contact with the coated substrate surface so as not to transmit light having a wavelength of 250 nm or less.
The coated film-forming substrate was subjected to UV / ozone treatment at 20 mW / cm ² while exhausting for 2 hours, and then measured with a contact-type profilometer. The film thickness was about 230 nm. When the coated film after the treatment was observed under a microscope, no cracks were observed.

<Confirmation of silicon oxide conversion>
Silicon oxide formation was confirmed by IR measurement. As shown in FIG. 1, and the peak around 2800～3600Cm ^-1 and around 1400～1800Cm ^-1 derived from the organic group is lost, the absorption around 800~1300cm _{^-1, SiO 3/2} decreases SiO _{4 /} It can be seen that ₂ is increasing.

From the above measurements, it was shown that a silicon oxide film can be obtained by forming a film of the copolymer (A) solution of the present invention on a CaF ₂ substrate and performing UV / ozone treatment.

<Measurement of refractive index>
When the refractive index was measured by the reflection spectroscopic film thickness meter FE-3000 manufactured by Otsuka Electronics Co., Ltd. using the value of the contact type film thickness measurement, the refractive index near 589 nm was about 1.45.

<Pencil hardness>
The composition of the copolymer (I) was applied to a silicon wafer or a glass substrate, and the pencil hardness of the silicon oxide film obtained by UV / ozone treatment was measured with a pencil hardness tester and found on a silicon wafer. It was found to be 6H or more and 6H on the glass substrate.

<Crosscut test>
The composition of the copolymer (I) was applied to a silicon Euha or a glass substrate, and a cross-cut test of a silicon oxide film obtained by UV / ozone treatment was performed. When carried out with a width of 1 mm and a width of 90 °, the peeling rate was 0% on both the silicon wafer and the glass, and the classification was 0.

<Measurement of transmittance>
The composition of the copolymer (I) was applied to a CaF ₂ substrate or a glass substrate, and the light transmittance of the silicon oxide film obtained by UV / ozone treatment was measured with an ultraviolet-visible spectrophotometer. , On CaF ₂ (220 to 800 nm) and on glass (400 to 800 nm), the transmittance was 90% or more.

<Continuous load scratch test>
The composition of the copolymer (I) was applied onto a silicon wafer, fired at 100 ° C., and then subjected to UV / ozone treatment to obtain a silicon oxide film having a thickness of 200 nm. The obtained silicon oxide film was subjected to a continuous load scratch test using the Tripogia TYPE: HHS2000 load-variable wear test system. A diamond R0.075 mm was used as the scratch needle. The load was measured in the range of 0 gf to 200 gf.
As a comparative example, a continuous load test was performed on a commercially available silicon wafer whose surface was thermally oxidized (silicon oxide film thickness 200 nm) by the same method.
The results of Examples and Comparative Examples are shown in FIG.
As shown in FIG. 2, it was confirmed that the silicon oxide film on the silicon wafer of the comparative example had an increase in frictional force at a load of about 100 gf. It is presumed that the silicon oxide film was destroyed or peeled off. No significant increase in frictional force was confirmed in the silicon oxide film of the example converted from the copolymer (I) of the present invention. From this, it is considered that the coating film is not destroyed or peeled off.
When a load was subsequently applied to the silicon oxide film of the example, an increase in frictional force was observed at around 300 gf. The results are shown in FIG.
From the above results, it was shown that the silicon oxide film converted from the copolymer of the present invention has excellent scratch resistance.

<Constant load measurement (slipperiness)>
The composition of the copolymer (I) was applied onto a silicon wafer, prebaked at 65 ° C., fired at 100 ° C., and then subjected to UV / ozone treatment to obtain a silicon oxide film having a thickness of 200 nm. A slipperiness test was performed on the obtained silicon oxide film using a ball indenter of 5 mmΦ and a load of 50 g.
As a comparative example, a slipperiness test was also performed on a commercially available silicon wafer whose surface was thermally oxidized (silicon oxide film thickness 200 nm) by the same method.

The silicon oxide film converted from the copolymer of the present invention showed lower static friction coefficient and dynamic friction coefficient than those of the comparative example. From the above results, it was found that the silicon oxide film converted from the product of the present invention has better slipperiness than the silicon oxide film on a normal silicon wafer. That is, it was confirmed that the surface of the silicon oxide film obtained by the present invention was smooth.

<Surface roughness>
The composition of the copolymer (I) is applied onto a silicon wafer, fired on a hot plate at 65 ° C. for 20 minutes, then fired at 85 ° C. for 20 minutes, and finally at 120 ° C. for 30 minutes. It was fired. The obtained coating film was subjected to UV / ozone treatment to obtain a silicon oxide film having a thickness of 200 nm. When the surface condition of the obtained silicon oxide film was measured using Bruker's three-dimensional optical interference surface roughness meter ContourGT, Ra (arithmetic mean roughness of the surface) was very 0.40 nm. It turned out to be a dense surface.

According to the present invention, an organic-inorganic addition copolymer capable of obtaining a silicon oxide film can be obtained inexpensively and easily.
Further, by using the organic-inorganic addition copolymer of the present invention, a silicon oxide film having high quality equivalent to that obtained by CVD or PVD and further excellent in abrasion resistance, smoothness and crack resistance can be obtained. be able to. This silicon oxide film is useful, for example, as a protective film for semiconductor devices.

Claims (6)

An addition copolymer consisting of a structural unit derived from the compound (A) represented by the formula (1) and a structural unit derived from the compound (B) represented by the formula (2).

In the formula (1), Ph is a phenyl group and A ¹ is a group having an addition-polymerizable functional group.

In the formula (2), R ¹ is a hydrogen atom or a linear or branched-chain alkyl having 1 to 20 carbon atoms, and the hydrogen atom bonded to the carbon atom of the alkyl is replaced with a hydroxyl group. If the number of carbon atoms is 2 or more, any methylene may be replaced with oxygen, and R ² may be any methylene substituted with oxygen. A linear or linear atom having 1 to 20 carbon atoms. branched alkylene, R ³ is a straight-chain or branched alkyl having 1 to 20 carbon atoms. The addition copolymer according to claim 1, wherein A ¹ is a group having a radically polymerizable functional group having (meth) acrylic. The addition copolymer according to claim 1, wherein the compound (A) is a compound represented by the formula (6).

The compound (B) is selected from N- (butoxymethyl) acrylamide, N- (methoxymethyl) methacrylamide, N- (isobutoxymethyl) acrylamide and N- (methoxymethyl) acrylamide, according to claims 1 to 3. The addition copolymer according to any one. A composition containing the addition copolymer according to any one of claims 1 to 4 and an organic solvent. A step of applying the composition according to claim 5 to a substrate,
A method for producing a silicon oxide film containing the structure of the formula (3), which comprises a step of irradiating the film obtained by the above step with ultraviolet rays to perform UV / ozone treatment .

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