JP4244315B2 - Resist pattern forming material - Google Patents

Description

The present invention relates to a resist pattern forming material having the resist material, an antireflection film for providing intermediate the base board and the resist film used in the production of semiconductor devices by lithography.

In recent years, with the progress of miniaturization of semiconductor elements, further miniaturization has been required for the lithography process used for the manufacture thereof. Then, when the general semiconductor manufacturing, a silicon wafer, a silicon oxide film, on a base plate such as an interlayer insulating film, a resist pattern is formed by lithography, it been conducted to etch the board as a mask However, for miniaturization, it is necessary to realize the control of the resist pattern line width with high accuracy while resolving a fine pattern for the resist.

However, if an attempt is made to realize this, in the radiation irradiating the resist in a pattern formation, reflection occurs at the boundary between the resist film and the underlying base plate bring critical. That is, when the reflection of the radiation takes place between the resist film and the underlying base plate, as a result of radiation intensity in the resist changes, the line width of the resist pattern varies, not precise pattern is obtained.

In order to suppress such disorders, but be provided with a coating such as an antireflection film or a protective film between the resist and the underlying base plate being carried out, the etching rate of the material constituting these coatings, since the approximate to that of the resist, on which a failure while transferring the resist pattern, caused troubles such as film reduction and the shape of the resist pattern in removing these coatings is deteriorated, the processing of the board With the disadvantage of reducing accuracy.

  In addition, in order to ensure sufficient etching resistance, the thickness of the resist film is also increased, but if this film thickness is increased too much, the aspect ratio between the line width of the resist pattern and the thickness of the resist film will be increased. There is a drawback that the resist pattern, particularly an isolated pattern, collapses in the development process and the resolution of the resist decreases in the exposure process.

  In addition, a three-layer resist process in which an intermediate layer is provided between the resist film and the coating, that is, the lower organic layer, is also performed. On this intermediate layer, a highly reproducible resist pattern is formed in good form. Characteristics such as high resistance to plasma etching, high plasma etching selectivity with the lower organic layer, and resistance to alkaline developer are required. Therefore, several materials have been proposed to meet this requirement.

  For example, although it has been proposed to provide an intermediate layer made of a hydrolyzate and / or condensate of an inorganic or organic silane compound (see Patent Document 1), this intermediate layer is prepared by applying a coating solution containing a silane compound. Because of the use, a conventional spin coating method cannot be used for film formation, and a dedicated coater track must be used, and in order to remove by-products generated during the condensation reaction, Since it requires firing at a high temperature of 300 ° C. or higher and a chromophore for radiation cannot be stably introduced, it has disadvantages such as difficulty in imparting antireflection ability.

  Also proposed is an organic antireflection hard mask comprising an inorganic element selected from the group of the periodic tables IIIa, IVa, Va, VIa, VIIa, VIII, Ib, IIb, IIIb, IVb or Vb on the dielectric layer. However, this also has a drawback that the antireflection ability necessary in case-by-case cannot be adjusted because the chromophore cannot be stably introduced with respect to radiation.

JP 2002-40668 A (Claims etc.) JP 2001-53068 A (Claims etc.)

The present invention is soluble in an organic solvent and can be easily applied by a conventional spin coating method, has good storage stability, and can adjust its antireflection ability by introducing a chromophore that absorbs radiation. An object of the present invention is to provide a resist pattern forming material having an antireflection film formed using a possible composition between a base substrate and a resist film .

The present inventors have found that an intermediate layer may be carried out efficiently antireflection by providing between the resist film and the underlying base plate, as a result of various studies on the hard mask material of the so-called three-layer resist process, having a specific composition A composition containing a ladder-type silicone copolymer, an acid generator, and a crosslinking agent is soluble in an organic solvent, can be easily applied by a conventional spin coating method, and can easily introduce a chromophore that absorbs radiation. Thus, it has been found that a stable antireflection film having an appropriately adjusted antireflection ability can be formed, and the present invention has been made based on this finding.

That is, according to the present invention, in the resist pattern forming material having an antireflection film between the base substrate and the resist film, the antireflection film comprises (A) (a ₁ ) (hydroxyphenylalkyl) silsesquioxane unit 10 90 mole%, (a ₂₎ (alkoxyphenyl alkyl) silsesquioxane units 0-50 mol% and (a ₃₎ full E d Lucille polymethylsilsesquioxane ladder silicone copolymer consisting San units 10 to 90 mol%, (B) A coating film formed from an organic solvent solution of an acid generator that generates an acid by heat or light and (C) a crosslinking agent , and an optical parameter for an ArF laser in the range of 0.002 to 0.95 ( The present invention provides a resist pattern forming material characterized by having a ( k value).

The composition used for forming the antireflection film in the present invention comprises (A) a ladder-type silicone copolymer, (B) an acid generator that generates an acid by heat or light, and (C) a crosslinking agent. It is contained as

又は

（式中のｎは１〜３の整数である）
で表わされる構成単位１０〜９０モル％と、（ａ₂）（アルコキシフェニルアルキル）シルセスキオキサン単位、すなわち一般式

又は

（式中のＲは炭素数１〜４の直鎖状又は枝分れ状低級アルキル基、ｎは１〜３の整数である）
で表わされる構成単位０〜５０モル％と、（ａ₃）フェニルシルセスキオキサン単位、すなわち式

又は

で表わされる構成単位１０〜９０モル％からなるラダー型シリコーン共重合体を用いることが必要である。上記一般式（ＩＩ）又は（ＩＩ´）中のＲとしては、メチル基が最も好ましい。また、上記一般式（Ｉ）と（ＩＩ）における−ＯＨ基と−ＯＲ基は、ｏ位、ｍ位及びｐ位のいずれの位置に結合していてもよいが、工業的にはｐ位に結合しているのが好ましい。また、（ａ₁）、（ａ₂）及び（ａ₃）単位は、通常上記一般式（Ｉ）、（ＩＩ）及び（ＩＩＩ）で表わされたり、（Ｉ´）、（ＩＩ´）、（ＩＩＩ´）と表わされたりするが、同じものである。
このラダー型シリコーン共重合体は、質量平均分子量（ポリスチレン換算）が１５００〜３００００の範囲にあるものが好ましく、３０００〜２００００の範囲にあるものが最も好ましい。分子量の分散度は１．０〜５．０の範囲であることが好ましく、１．２〜３．０であることが最も好ましい。 The ladder type silicone copolymer of component (A) includes (a ₁ ) (hydroxyphenylalkyl) silsesquioxane units, that is, the general formula

Or

(Where n is an integer of 1 to 3)
And (a ₂ ) (alkoxyphenylalkyl) silsesquioxane unit, that is, the general formula

Or

(In the formula, R is a linear or branched lower alkyl group having 1 to 4 carbon atoms, and n is an integer of 1 to 3)
In the structural unit 0-50 mol% represented, (a ₃₎ full E D silsesquioxane units, i.e. formula

Or

It is necessary to use a ladder silicone copolymer comprising constituent units 10 to 90 mole% represented in. As R in the general formula (II) or (II ′), a methyl group is most preferable . In the general formulas (I) and (II), the —OH group and —OR group may be bonded to any position of the o-position, m-position and p-position, but industrially in the p-position. Bonding is preferred. The units (a ₁ ), (a ₂ ) and (a ₃ ) are usually represented by the above general formulas (I), (II) and (III), or (I ′), (II ′), Although it is expressed as (III '), it is the same thing.
The ladder type silicone copolymer preferably has a mass average molecular weight (polystyrene conversion) in the range of 1500 to 30000, and most preferably in the range of 3000 to 20000. The molecular weight dispersity is preferably in the range of 1.0 to 5.0, and most preferably 1.2 to 3.0.

  Next, the acid generator that generates acid by heat or light of component (B) is a substance that is usually used as a component of a chemically amplified resist composition. Although it can select and use, onium salt and a diazomethane type compound are especially preferable.

  Examples of such an acid generator include diphenyliodonium trifluoromethanesulfonate or nonafluorobutanesulfonate, bis (4-tert-butylphenyl) iodonium trifluoromethanesulfonate or nonafluorobutanesulfonate, triphenylsulfonium trifluoromethanesulfonate or nona. Onium salts such as fluorobutanesulfonate, trifluoromethanesulfonate of tri (4-methylphenyl) sulfonium or nonafluorobutanesulfonate, bis (p-toluenesulfonyl) diazomethane, bis (1,1-dimethylethylsulfonyl) diazomethane, bis ( Isopropylsulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane, bis (2,4-dimethylphenol) Nirusuruhoniru) can be exemplified diazomethane-based compounds such as diazomethane. Particularly preferred among these are onium salts having a decomposition point of 250 ° C. or lower, such as triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluorobutanesulfonate, and 7,7-dimethyl-bis (pt-butylphenyl) iodonium. Bicyclo- [2,2,1] -heptan-2-one-1-sulfonate and the like.

  This (B) component acid generator may be used independently and may be used in combination of 2 or more types. The content is normally selected in the range of 0.5 to 20 parts by mass, preferably 1 to 10 parts by mass with respect to 100 parts by mass of the component (A). If the acid generator is less than 0.5 parts by mass, it is difficult to form an antireflection film, and if it exceeds 20 parts by mass, the solution is not uniform and storage stability is reduced.

で表わされる２，４，６，８‐テトラ‐ｎ‐ブトキシメチル‐ビシクロ［１．０．１］‐２，４，６，８‐テトラアザオクタン‐３，７‐ジオンや、式

で表わされるヘキサメトキシメチルメラミンが好ましい。
これらの架橋剤は、（Ａ）１００質量部当り１〜１０質量部の範囲内で用いるのがよい。 Moreover, the crosslinking agent of (C) component should just be what can bridge | crosslink (A) component and form a suitable film as a hard mask material, when a composition of this invention is heated or baked, and there is no restriction | limiting in particular. Compounds with two or more reactive groups, such as divinylbenzene, divinylsulfone, triacryl formal, glyoxal and polyhydric alcohol acrylates or methacrylates, melamine, urea, benzoguanamine, glycoluril amino Those in which at least two of the groups are substituted with a methylol group or a lower alkoxymethyl group are preferred. Among them, especially the formula

2,4,6,8-tetra-n-butoxymethyl-bicyclo [1.0.1] -2,4,6,8-tetraazaoctane-3,7-dione represented by the formula

The hexamethoxymethylmelamine represented by these is preferable.
These crosslinking agents are preferably used within a range of 1 to 10 parts by mass per 100 parts by mass of (A).

In the present invention, the composition used to form the anti-reflection film, the above component (A) is a solution obtained by dissolving in an organic solvent (B) component and the (C) component, this time The organic solvent to be used can be arbitrarily selected from those capable of dissolving the required amounts of these three components, but those having a boiling point of 150 ° C. or higher are preferable in consideration of firing conditions. Examples of the solvent include ketones such as acetone, methyl ethyl ketone, cyclohexanone, and methyl isoamyl ketone, ethylene glycol, ethylene glycol monoacetate, propylene glycol, propylene glycol monoacetate, diethylene glycol or monoethylene ether of diethylene glycol monoacetate, monoethyl ether, Polyhydric alcohols such as monopropyl ether, monobutyl ether or monophenyl ether and derivatives thereof, cyclic ethers such as dioxane, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, Esters such as ethyl pyruvate are used. These may be used alone or in combination of two or more.
This organic solvent is used in an amount of 1 to 20 times, preferably 2 to 10 times the amount based on the total solid content.

In the present invention, the composition used to form the anti-reflection film is also an optical parameter (k value) for the light of ArF laser i.e. wavelength 193nm is from 0.002 to 0.95, preferably 0.1 to 0. 7, more preferably, it is necessary to adjust so as to form an antireflection film in the range of 0.15 to 0.4. This adjustment can be performed, for example, by increasing or decreasing the content ratio of the component (a ₂ ) in the component (A). By adjusting to such a range, a low and stable reflectance is exhibited when the thickness of the antireflection film is 40 to 200 nm.

Then, in the present invention, the composition used to form the anti-reflection film, the above (A), (B) is added to the ingredients and the component (C), as further component (D) if necessary Linear polymers can be included.

In this composition, the linear polymer used as the component (D) is a polymer containing at least a hydroxyl group-containing (meth) acrylate unit as a constituent unit, that is, a hydroxyl group-containing (meth) acrylate homopolymer or hydroxyl group-containing polymer. A copolymer of (meth) acrylic acid ester and another copolymerizable monomer is preferable.

  Thus, by using a polymer containing a hydroxyl group as the component (D), this hydroxyl group promotes a high molecular weight as a crosslinking aid, and the effect of significantly improving the stability to a resist solvent or a developer is exhibited. This effect is increased particularly when a hydroxyl group-containing (meth) acrylic acid ester having an aliphatic polycyclic group such as an adamantyl group as a side chain is used.

  When this linear polymer is a hydroxyl group-containing (meth) acrylic acid ester copolymer, the monomer component copolymerized with the hydroxyl group-containing (meth) acrylic acid ester is not particularly limited, and is a known monomer conventionally used in ArF resists. Any of these can be selected and used.

（式中、Ｒ¹は水素原子又はメチル基、Ｒ²は低級アルキル基である）
で表わされる構成単位１０〜６０モル％、好ましくは２０〜４０モル％、（ｄ₂）一般式

（式中のＲ³は水素原子又はメチル基である）
で表わされる構成単位３０〜８０モル％、好ましくは２０〜５０モル％、及び（ｄ₃）一般式

（式中、Ｒ⁴は水素原子又はメチル基である）
で表わされる構成単位１０〜５０モル％、好ましくは２０〜４０モル％からなる線状共重合体を挙げることができる。
上記一般式（Ｖ）中のＲ²としては、炭素数１〜５の低級アルキル基、特にメチル基やエチル基が工業的な面から好ましい。 Among the above linear polymers containing a hydroxyl group-containing (meth) acrylic acid ester unit, (d ₁ )

(Wherein R ¹ is a hydrogen atom or a methyl group, and R ² is a lower alkyl group)
10 to 60 mol%, preferably 20 to 40 mol%, (d ₂ )

(Wherein R ³ is a hydrogen atom or a methyl group)
30 to 80 mol%, preferably 20 to 50 mol%, and (d ₃ )

(Wherein R ⁴ is a hydrogen atom or a methyl group)
The linear copolymer which consists of 10-50 mol% of the structural unit represented by this, Preferably 20-40 mol% can be mentioned.
As R < ² > in the said general formula (V), a C1-C5 lower alkyl group, especially a methyl group and an ethyl group are preferable from an industrial surface.

The linear polymer as the component (D) preferably has a mass average molecular weight in the range of 5000 to 20000.
This (D) component is mix | blended in the ratio of 10-100 mass parts per 100 mass parts of (A) component.

Next, in the present invention , the composition used for forming the antireflection film is added to the component (A), the component (B), the component (C), and the component (D) optionally mixed. In addition, a conventional ionic or nonionic surfactant can be added to impart dispersibility and coating film uniformity.

  These surfactants are added at a ratio of 0.05 to 1.0 part by mass per 100 parts by mass of the total solid content.

In the present invention, to form the antireflection film, the composition described above, using conventional spin coating method based board such as a silicon wafer can be easily applied, antireflective desired thickness A film can be formed. This in to the registration process, an oxide film is formed on the base plate by vapor deposition, given that it was necessary to apply a resist film thereon, it is understood that it is highly simplified.

To form the antireflection film is spin-coated on a base plate, after drying, the boiling point of the solvent or less, for example at 100 to 120 ° C., 60-120 seconds, then at 200 to 250 ° C., heated for 60 to 120 seconds It is preferable to use a multistage heating method. Thus, after forming an antireflection film having a thickness of 40 to 200 nm, a resist film is provided thereon in a thickness of 100 to 300 nm by a conventional method to produce a resist material. In this case, the organic film is provided in a thickness of first 200~600nm on a base plate, an intermediate layer of the organic film and the resist film, by forming the reflection preventing film described above, also be a three-layer resist material it can.

The ladder silicone copolymer of the component (A) base resin component of the composition used to form the anti-reflection film, an optical parameter (k value, especially for light of ArF laser i.e. wavelength 193nm of the composition ) Is important as a component when adjusting to 0.002 to 0.95, and such adjustment can be performed effectively. In addition, the silicon content in the copolymer is high and the O ₂ plasma resistance is high, which is preferable.
The ladder-type silicone copolymer can be synthesized by a method known per se, for example, the method described in Production Example 1 of Japanese Patent No. 2567984.

Among the ladder type silicone copolymers of component (A), a copolymer containing a combination of a (hydroxyphenylalkyl) silsesquioxane unit and an alkylsilsesquioxane unit is a novel compound not described in any literature. . In order to use this for the composition used for forming the antireflection film , the content ratio of the (hydroxyphenylalkyl) silsesquioxane unit to the alkylsilsesquioxane unit is 10:90 to 90: Those having a range of 10 are preferred, and among them, those having a mass average molecular weight of 1500 to 30000, particularly 3000 to 20000, and a degree of dispersion of 1.0 to 5.0, particularly 1.2 to 3.0. preferable.

According to the present invention, by a spin coating method using a conventional resist coater, can be easily applied, storage stability, oxygen plasma etching resistance is good, might give the mask pattern of good profile shape.

Next, the best mode for carrying out the present invention will be described in more detail by way of examples. However, the present invention is not limited to these examples.
In each example, the following compounds were used as the acid generator (B) component, the crosslinking agent (C) component, and the linear polymer (D) component.

（２）架橋剤；
（Ｃ₁）成分

又は
（Ｃ₂）成分

（３）線状ポリマー；
（Ｄ）成分
２‐エチル‐２‐アダマンチルアクリレート単位、一般式（ＶＩ）におけるＲ³が水素原子である単位及び３‐ヒドロキシ‐１‐アダマンチルアクリレート単位をそれぞれ３０モル％、４０モル％及び３０モル％含むアクリレートタイプポリマー
質量平均分子量１００００ (1) an acid generator;
(B) component

(2) cross-linking agent;
(C ₁₎ component

Or (C ₂ ) component

(3) a linear polymer;
(D) component 2-ethyl-2-adamantyl acrylate unit, R ³ in the general formula (VI) is a hydrogen atom, and 3-hydroxy-1-adamantyl acrylate unit are 30 mol%, 40 mol% and 30 mol, respectively. Acrylate type polymer containing 1% weight average molecular weight 10,000

In addition, the optical parameter (k value: extinction coefficient) in each Example is a numerical value measured by the following method.
That is, a sample was applied on an 8-inch silicon wafer to form a coating film having a thickness of 50 nm, and measured by spectroscopic ellipsometry (JA WOOLLAM, “VUV-VASE”). Analysis was performed with analysis software (WVASE32).

Reference example 1
A 500 ml three-necked flask equipped with a stirrer, a reflux condenser, a dropping funnel and a thermometer was charged with 1.00 mol (84.0 g) of sodium hydrogen carbonate and 400 ml of water, and then p-methoxybenzyl trichloride was added from the dropping funnel. A solution obtained by dissolving 0.36 mol (92.0 g) of chlorosilane and 0.14 mol (29.6 g) of phenyltrichlorosilane in 100 ml of diethyl ether was added dropwise while stirring over 2 hours, and then heated under reflux for 1 hour. After completion of the reaction, the reaction product was extracted from the reaction mixture with diethyl ether, and diethyl ether was distilled off from the extract under reduced pressure to recover the hydrolysis product.
By adding 0.33 g of 10% by mass-potassium hydroxide aqueous solution to the hydrolysis product thus obtained and heating at 200 ° C. for 2 hours, 72 mol% of p-methoxybenzylsilsesquioxane unit and phenylsil A copolymer A ₁ (64.4 g) consisting of 28 mol% of sesquioxane units was produced. Proton NMR of the copolymer A _1, infrared absorption spectrum, the analysis of GPC (gel permeation chromatography) are shown below.
¹ H-NMR (DMSO-d ₆ ): δ = 2.70 ppm (—CH ₂ —), 3.50 ppm (—OCH ₃ ), 6.00 to 7.50 ppm (benzene ring)
IR (cm ⁻¹ ): ν = 1178 (—OCH ₃ ), 1244, 1039 (—SiO—)
Mass average molecular weight (Mw): 7500, Dispersity (Mw / Mn): 1.8

Then, the copolymer A ₁ to a solution obtained by dissolving in acetonitrile 150 ml, was added trimethylsilyl iodide 0.4 mol (80.0 g), After stirring 24 hours under reflux, water 50ml was added, further The reaction was stirred for 12 hours under reflux. After cooling, free iodine was reduced with an aqueous sodium hydrogen sulfite solution, the organic layer was separated, and the solvent was distilled off. The residue was reprecipitated with acetone and n-hexane and dried by heating under reduced pressure to give a copolymer A ₂ (comprising 72 mol% of p-hydroxybenzylsilsesquioxane units and 28 mol% of phenylsilsesquioxane units). 39.0 g) was produced. Proton NMR of the copolymer A _2, infrared absorption spectrum, the analysis of GPC (gel permeation chromatography) are shown below.
¹ H-NMR (DMSO-d ₆ ): δ = 2.70 ppm (—CH ₂ —), 6.00 to 7.50 ppm (benzene ring), 8.90 ppm (—OH)
IR (cm ⁻¹ ): ν = 3300 (—OH), 1244, 1047 (—SiO—)
Mass average molecular weight (Mw): 7000, Dispersity (Mw / Mn): 1.8

Reference example 2
To a solution obtained by dissolving the copolymer A ₁ produced in Reference Example 1 in 150 ml of acetonitrile, 0.250 mol (50.0 g) of trimethylsilyliodide was added, stirred for 24 hours under reflux, and then 50 ml of water was added. The mixture was further stirred for 12 hours under reflux and reacted. After cooling, free iodine was reduced with an aqueous sodium hydrogen sulfite solution, the organic layer was separated, and the solvent was distilled off. The residue was reprecipitated with acetone and n-hexane and dried by heating under reduced pressure to obtain 36 mol% of p-hydroxybenzylsilsesquioxane unit, 36 mol% of p-methoxybenzylsilsesquioxane unit and phenylsilsesquioxane. A copolymer A ₃ (40.3 g) consisting of 28 mol% of sun units was produced. Proton NMR of the copolymer A _3, infrared absorption spectrum, the analysis of GPC (gel permeation chromatography) are shown below.
¹ H-NMR (DMSO-d ₆ ): δ = 2.70 ppm (—CH ₂ —), 3.50 ppm (—OCH ₃ ), 6.00 to 7.50 ppm (benzene ring), 8.90 ppm (—OH )
IR (cm ⁻¹ ): ν = 3300 (—OH), 1178 (—OCH ₃ ), 1244, 1047 (—SiO—)
Mass average molecular weight (Mw): 7000, Dispersity (Mw / Mn): 1.8

Reference example 3
To a solution obtained by dissolving the copolymer A ₁ produced in Reference Example 1 in 150 ml of acetonitrile, 0.347 mol (69.4 g) of trimethylsilyliodide was added, stirred for 24 hours under reflux, and then 50 ml of water was added. The mixture was further stirred for 12 hours under reflux and reacted. After cooling, free iodine was reduced with an aqueous sodium hydrogen sulfite solution, the organic layer was separated, and the solvent was distilled off. The residue was reprecipitated with acetone and n-hexane and dried by heating under reduced pressure to give 50 mol% p-hydroxybenzylsilsesquioxane units, 22 mol% p-methoxybenzylsilsesquioxane units, and phenylsilsesquioxy units. Copolymer A ₄ (39.8 g) comprising 28 mol% of sun units was produced. Proton NMR of the copolymer A _4, infrared absorption spectrum, the analysis of GPC (gel permeation chromatography) are shown below.
¹ H-NMR (DMSO-d ₆ ): δ = 2.70 ppm (—CH ₂ —), 3.50 ppm (—OCH ₃ ), 6.00 to 7.50 ppm (benzene ring), 8.90 ppm (—OH )
IR (cm ⁻¹ ): ν = 3300 (—OH), 1178 (—OCH ₃ ), 1244, 1047 (—SiO—)
Mass average molecular weight (Mw): 7000, Dispersity (Mw / Mn): 1.8

Reference example 4
A 500 ml three-necked flask equipped with a stirrer, a reflux condenser, a dropping funnel and a thermometer was charged with 1.00 mol (84.0 g) of sodium hydrogen carbonate and 400 ml of water, and then p-methoxybenzyl trichloride was added from the dropping funnel. A solution obtained by dissolving 0.36 mol (92.0 g) of chlorosilane and 0.14 mol (24.9 g) of n-propyltrichlorosilane in 100 ml of diethyl ether was added dropwise while stirring for 2 hours, and then heated under reflux for 1 hour. did. After completion of the reaction, the reaction product was extracted with diethyl ether, and diethyl ether was distilled off from the extract under reduced pressure.
By adding 0.33 g of 10% by mass-potassium hydroxide aqueous solution to the hydrolysis product thus obtained and heating at 200 ° C. for 2 hours, 72 mol% of p-methoxybenzylsilsesquioxane unit and n- A copolymer A ₅ (60.6 g) consisting of 28 mol% of propylsilsesquioxane units was produced. Proton NMR of the copolymer A _5, the infrared absorption spectrum, the analysis of GPC (gel permeation chromatography) are shown below.
¹ H-NMR (DMSO-d ₆ ): δ = 1.00 to 2.00 ppm (−n-Propyl), 2.70 ppm (—CH ₂ —), 3.50 ppm (—OCH ₃ ), 6.00 7.50ppm (benzene ring)
IR (cm ⁻¹ ): ν = 1178 (—OCH ₃ ), 1244, 1039 (—SiO—)
Mass average molecular weight (Mw): 7500, Dispersity (Mw / Mn): 1.8

Then, the copolymer A ₅ solution obtained by dissolving in acetonitrile 150 ml, was added trimethylsilyl iodide 0.4 mol (80.0 g), After stirring 24 hours under reflux, water 50ml was added, further The reaction was stirred for 12 hours under reflux. After cooling, free iodine was reduced with an aqueous sodium hydrogen sulfite solution, the organic layer was separated, and the solvent was distilled off. The residue was reprecipitated with acetone and n-hexane and dried under reduced pressure to obtain copolymer A comprising 72 mol% of p-hydroxybenzylsilsesquioxane units and 28 mol% of n-propylsilsesquioxane units. ₆ (36.6 g) was produced. Proton NMR of the copolymer A _6, infrared absorption spectrum, the analysis of GPC (gel permeation chromatography) are shown below.
¹ H-NMR (DMSO-d ₆ ): δ = 1.00 to 2.00 ppm (-n-Propyl), 2.70 ppm (—CH ₂ —), 6.00 to 7.50 ppm (benzene ring), 8 90 ppm (-OH)
IR (cm ⁻¹ ): ν = 3300 (—OH), 1244, 1047 (—SiO—)
Mass average molecular weight (Mw): 7000, Dispersity (Mw / Mn): 1.8

Reference Example 5
A 500 ml three-necked flask equipped with a stirrer, a reflux condenser, a dropping funnel and a thermometer was charged with 1.00 mol (84.0 g) of sodium hydrogen carbonate and 400 ml of water, and then p-methoxybenzyl trichloride was added from the dropping funnel. A solution obtained by dissolving 0.32 mol (81.8 g) of chlorosilane and 0.18 mol (38.1 g) of phenyltrichlorosilane in 100 ml of diethyl ether was added dropwise while stirring over 2 hours, and then heated under reflux for 1 hour. After completion of the reaction, the reaction product was extracted with diethyl ether, and diethyl ether was distilled off from the extract under reduced pressure.
By adding 0.33 g of 10% by weight-potassium hydroxide aqueous solution to the hydrolysis product thus obtained and heating at 200 ° C. for 2 hours, 64 mol% of p-methoxybenzylsilsesquioxane unit and phenylsil A copolymer A ₇ (62.9 g) consisting of 36 mol% of sesquioxane units was produced. Proton NMR of the copolymer A _7, infrared absorption spectrum, the analysis of GPC (gel permeation chromatography) are shown below.
¹ H-NMR (DMSO-d ₆ ): δ = 2.70 ppm (—CH ₂ —), 3.50 ppm (—OCH ₃ ), 6.00 to 7.50 ppm (benzene ring)
IR (cm ⁻¹ ): ν = 1178 (—OCH ₃ ), 1244, 1039 (—SiO—)
Mass average molecular weight (Mw): 7500, Dispersity (Mw / Mn): 1.8

Then, the copolymer A ₇ in a solution obtained by dissolving in acetonitrile 150 ml, was added trimethylsilyl iodide 0.4 mol (80.0 g), After stirring 24 hours under reflux, water 50ml was added, further The reaction was stirred for 12 hours under reflux. After cooling, free iodine was reduced with an aqueous sodium hydrogen sulfite solution, the organic layer was separated, and the solvent was distilled off. The residue was reprecipitated with acetone and n-hexane and dried by heating under reduced pressure, whereby copolymer A ₈ (comprising 64 mol% of p-hydroxybenzylsilsesquioxane units and 36 mol% of phenylsilsesquioxane units) ( 38.4 g) was produced. Proton NMR of the copolymer A _8, the infrared absorption spectrum, the analysis of GPC (gel permeation chromatography) are shown below.
¹ H-NMR (DMSO-d ₆ ): δ = 2.70 ppm (—CH ₂ —), 6.00 to 7.50 ppm (benzene ring), 8.90 ppm (—OH)
IR (cm ⁻¹ ): ν = 3300 (—OH), 1244, 1047 (—SiO—)
Mass average molecular weight (Mw): 7000, Dispersity (Mw / Mn): 1.8

Ladder type silicone copolymer, that is, as component (A), copolymer A ₂ (mass average molecular weight) comprising 72 mol% of p-hydroxybenzylsilsesquioxane units and 28 mol% of phenylsilsesquioxane units. 7000), 83 parts by weight of the component (A), 3 parts by weight of the component (B) as the acid generator and 5 parts by weight of the component (C ₁ ) as the crosslinking agent, and the acrylate as the component (D). The mixture obtained by adding 17 parts by mass of the type polymer was dissolved in 300 parts by mass of propylene glycol monopropyl ether to prepare a composition for forming an antireflection film.
Next, the above composition is applied onto a silicon wafer using a conventional resist coater, and a two-step heat treatment is performed at 100 ° C. for 90 seconds and then at 250 ° C. for 90 seconds to obtain a thickness. An antireflection film having a thickness of 55 nm was formed.
The optical parameter (k value) of this antireflection film was 0.67.
Thus, the coating film of different thickness was formed, the reflectance with respect to thickness was measured, and it shows in FIG. 1 as a graph.
As can be seen from this figure, when the k value is 0.67, a stable low reflectance is exhibited in the working film thickness range of 40 to 150 nm.

The copolymer of Reference Example 2 comprising, as component (A), 36 mol% of p-hydroxybenzylsilsesquioxane units, 36 mol% of p-methoxybenzylsilsesquioxane units and 28 mol% of phenylsilsesquioxane units. Using A ₃ (mass average molecular weight 7000), 100 parts by mass of the component (A), 3 parts by mass of the component (B) as an acid generator, and 5 parts by mass of the component (C ₁ ) as a crosslinking agent are mixed with propylene glycol. An antireflection film-forming composition was prepared by dissolving in 300 parts by mass of a mixture (mass ratio 40/60) of monomethyl ether monoacetate and propylene glycol monomethyl ether.
Next, the above composition is applied onto a silicon wafer using a conventional resist coater, and heat treatment is performed in two stages under the conditions of 100 ° C. for 90 seconds and then 250 ° C. for 90 seconds. An antireflection film having a thickness of about 50 nm was formed.
The optical parameter (k value) of this antireflection film was 0.67.

Copolymer of Reference Example 3 comprising, as component (A), 50 mol% of p-hydroxybenzylsilsesquioxane units, 22 mol% of p-methoxybenzylsilsesquioxane units and 28 mol% of phenylsilsesquioxane units. Using A ₄ (mass average molecular weight 7000), 100 parts by mass of the component (A), 3 parts by mass of the component (B) as an acid generator, and 5 parts by mass of the component (C ₁ ) as a crosslinking agent are mixed with propylene glycol. An antireflection film-forming composition was prepared by dissolving in 300 parts by mass of monomethyl ether monoacetate.
This composition was applied onto a silicon wafer in the same manner as in Example 1 , heated at 100 ° C. for 90 seconds, and then heated at 230 ° C. for 90 seconds to form an antireflection film having a thickness of 70 nm. The optical parameter (k value) of this antireflection film was 0.90.

An antireflection film having a thickness of 70 nm was formed in the same manner as in Example 3 except that the heat treatment was changed to a one-step heat treatment at 250 ° C. for 90 seconds.
The optical parameter (k value) of this antireflection film was 0.90.

As the component (A), 83 parts by mass of the copolymer A ₆ obtained in Reference Example 4 , 3 parts by mass of the component (B) as an acid generator, and 5 parts by mass of the component (C ₁ ) as a crosslinking agent are added. Further, a mixture obtained by adding 17 parts by mass of the component (D) as a linear polymer was dissolved in 300 parts by mass of propylene glycol monopropyl ether to prepare an antireflection film-forming composition. Next, the above composition is applied onto a silicon wafer using a conventional resist coater, and heat treatment is performed in two stages under the conditions of 100 ° C. for 90 seconds and then 250 ° C. for 90 seconds. An antireflection film having a thickness of 55 nm was formed.
The optical parameter (k value) of this antireflection film was 0.55.

As component (A), copolymer A ₈ (mass average molecular weight 7000) of Reference Example 5 consisting of 64 mol% of p-hydroxybenzylsilsesquioxane units and 36 mol% of phenylsilsesquioxane units was used. A) 83 parts by mass of the component, 3 parts by mass of the (B) component as an acid generator and 5 parts by mass of the (C ₂ ) component as a crosslinking agent, and 17 parts by mass of the (D) component as a linear polymer are added. The mixture obtained in addition was dissolved in 300 parts by mass of propylene glycol monopropyl ether to prepare an antireflection film-forming composition. Next, the above composition is applied onto a silicon wafer using a conventional resist coater, and heat treatment is performed in two stages under the conditions of 100 ° C. for 90 seconds and then 250 ° C. for 90 seconds. An antireflection film having a thickness of 75 nm was formed.
The optical parameter (k value) of this antireflection film was 0.49.

Comparative Example As a composition for forming an antireflection film, a coating solution mainly composed of a mixture of a commercially available co-hydrolyzate of tetraalkoxysilane and methyltrialkoxysilane and a condensate (manufactured by Tokyo Ohka Kogyo Co., Ltd., trade name “OCD T- 7 ML02 ”) and coated on a silicon wafer with a SOG-dedicated coater and heat-treated in three stages under conditions of 80 ° C. for 90 seconds, then 150 ° C. for 90 seconds, and finally 250 ° C. for 90 seconds. As a result, an antireflection film having a thickness of 50 nm was formed.
The coating solution immediately formed a powdery precipitate as the solution was dried, and this was contaminated with a coating nozzle, a coater cup, a wafer, etc., and thus could not be applied with a conventional resist coater.

Application Examples The antireflection film-forming compositions in the above Examples and Comparative Examples were tested for storage stability, applicability with a resist coater, and oxygen plasma etching resistance by the following methods. The results are shown in Table 1. It was.

(1) Storage stability (change in film thickness);
A predetermined composition stored at room temperature (20 ° C.) or frozen (−20 ° C.) for 45 days is prepared, spin-coated on an 8-inch silicon wafer under the same coating conditions, and dried to form a coating film. Each film thickness when formed was measured, and the case where the difference in the film thickness of the room temperature storage sample with respect to the frozen storage sample was within 5% was marked as ◯, and the case where it was larger was marked as x.

(2) Storage stability (particle generation);
In addition, with respect to the sample stored at room temperature (1), the number of particles having a particle size of 0.22 μm or more was measured with a particle counter [manufactured by Rion, product name “Particle Sensor KS-41”], 300 pieces The following cases were evaluated as ○, and the cases exceeding the case were evaluated as ×.

(3) Resist coater application possibility;
In order to be able to be applied by a resist coater, it is necessary that no particles are generated in the edge rinse process and the auto dispense process. Therefore, it was dissolved in propylene glycol methyl ether acetate, propylene glycol monomethyl ether and ethyl lactate used as an edge rinse, and the presence or absence of particles was observed. did.

(4) Oxygen plasma etching resistance (etching rate);
The sample was etched under the following conditions, and the etching rate was determined. The smaller this value, the better the oxygen plasma etching resistance.
Etching device: GP-12 (Tokyo Oka Kogyo Co., Ltd., oxygen plasma etching device)
Etching gas; O ₂ / N ₂ (60/40 sccm)
Pressure; 0.4Pa
Output: 1600W
Bias power: 150W
Stage temperature: -10 ° C

The resist pattern forming material of the present invention is suitable for manufacturing semiconductor devices.

The graph which shows the relationship between the film thickness and reflectance about this invention composition of optical parameter (k value) 0.67.

Claims (5)

In the resist pattern forming material having an antireflection film between the base substrate and the resist film, the antireflection film comprises (A) (a ₁ ) (hydroxyphenylalkyl) silsesquioxane units of 10 to 90 mol%, ( a ₂₎ (alkoxyphenyl alkyl) silsesquioxane units 0-50 mol% and (a ₃₎ full E d Lucille polymethylsilsesquioxane ladder silicone copolymer consisting San units 10 to 90 mol%, (B) heat or light A coating film formed from an organic solvent solution of an acid generator that generates an acid and (C) a crosslinking agent , and having an optical parameter (k value) for an ArF laser in the range of 0.002 to 0.95 resist pattern forming material characterized in that it. The resist pattern forming material according to claim 1, further comprising (D) a linear polymer in addition to the component (A), the component (B), and the component (C). The resist pattern forming material according to claim 2, wherein the (D) linear polymer is a polymer containing at least a hydroxyl group-containing (meth) acrylate unit. The resist pattern forming material according to claim 3, wherein the (D) linear polymer is a polymer containing a (meth) acrylic acid ester unit having at least a hydroxyl group-containing aliphatic polycyclic group. The (D) linear polymer is represented by the formula (d ₁ )

(Wherein R ¹ is a hydrogen atom or a methyl group, and R ² is a lower alkyl group)
In structural unit from 10 to 60 mol% represented, (d ₂₎ the general formula

(Wherein R ³ is a hydrogen atom or a methyl group)
In the structural unit 30-80 mol% represented, and (d ₃₎ the general formula

(Wherein R ⁴ is a hydrogen atom or a methyl group)
The resist pattern forming material according to claim 3, which is a linear copolymer comprising 10 to 50 mol% of a structural unit represented by:

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