JP5413105B2 - Resist pattern forming method and plating pattern forming method - Google Patents

Description

  The present invention relates to a method for forming a resist pattern that enables formation of a thick resist pattern using a positive resist composition. Furthermore, the present invention relates to a plating pattern forming method including a step of forming on a substrate a metal plating layer, which is a connection terminal having a height of 10 μm or more, called a bump, in the manufacture of an LSI circuit board.

  In recent years, with the downsizing of electronic devices, LSIs have been highly integrated and ASICs are rapidly progressing, and multi-pin thin layer mounting for that purpose is widely used. In such a multi-pin structure, a protruding electrode (bump) having a height of 10 μm or more, which is a connection terminal, is essential, and a technique for forming it on an LSI by a plating method using a photoresist material is required. ing. On the other hand, with a mushroom-type bump shape formed using a conventional thin film resist layer, it has been difficult to increase the number of LSI pins and increase the pin spacing density. Therefore, it is necessary to use a thick resist layer to make the bump-shaped side walls vertical (straight side walls). Therefore, the thick photoresist layer for the plating process must have high sensitivity, shape perpendicularity, and high resolution, particularly crack resistance during or after the plating process.

  Conventionally, various materials using a novolak resin as a base polymer have been proposed as materials for forming the bumps (Patent Document 1: JP-A-2005-134800). In such a conventional novolak-diazonaphthoquinone-based resist composition, generally, a post-exposure baking (hereinafter referred to as “PEB”) process is not used, and a development process is performed after the exposure. However, the conventional resist material has poor transparency and the sensitivity of the thick film necessary for forming the bumps is low.

  For this reason, in order to further increase the sensitivity, a material based on polyhydroxystyrene, a material based on a polymer containing an acrylic or methacrylic resin, a polyhydroxystyrene and an acrylic or methacrylic resin are used. A chemically amplified resist material using a mixed polymer as a base polymer has been proposed. In such a chemically amplified resist material, after exposure, diffusion of acid is promoted using a known method to change the alkali solubility of the resist layer in the exposed portion (Patent Document 2: Japanese Patent Application Laid-Open No. 2004-2005). 309777). On the other hand, a means for forming a pattern by developing a resist layer in an exposed region that has become alkali-soluble by exposure to a thick film resist layer having a thickness of 20 μm or more, and then using an alkaline solution is proposed ( (Patent Document 3: Japanese Patent Laid-Open No. 2006-267475). However, resolution may be inferior unless a heat treatment step after exposure is performed.

  As is well known, in a chemically amplified resist material, a substance (acid or base) having a catalytic action is generated by a photochemical reaction, and this substance and a polymer in a polymer are subjected to a subsequent heat treatment step (PEB: post-exposure baking). This PEB process is indispensable because it reacts with a functional group or a functional substance (Non-patent Document 1: Resist Material Handbook for Semiconductor Integrated Circuit, 1996, p. 149). In particular, in the chemically amplified resist material applied and formed with a film thickness of 20 to 120 μm, it is required to shorten the process time such as the time required for the PEB process, and the fluctuation of the holding time from the exposure to the PEB process. Variations in the finished dimensions and shape due to the problem have become a problem.

JP-A-2005-134800 JP 2004-309777 A JP 2006-267475 A

Resist material handbook for semiconductor integrated circuits, 1996, p. 149

  The present invention can form a thick bump resist pattern (resist layer) using g-line, i-line, broadband including g-line and i-line, or ultraviolet light typified by KrF excimer laser as an exposure light source. It is an object to provide a method for forming a resist pattern and a plating pattern using a positive resist composition.

（式中、Ｒ¹は水素原子又は下記一般式（２）で示される官能基を示す。）

（式中、Ｒ²、Ｒ³は、互いに独立して、水素原子又は炭素数１〜６の直鎖状、分岐状又は環状のアルキル基を示す。Ｒ⁴は、炭素数１〜３０の直鎖状、分岐状又は環状のアルキル基、炭素数６〜２０のアリール基又は炭素数７〜２０のアラルキル基を示す。Ｒ²とＲ³、Ｒ²とＲ⁴又はＲ³とＲ⁴は互いに結合してこれらが結合する炭素原子又は炭素原子と酸素原子と共に環を形成してもよく、環を形成する場合、環の形成に関与するＲ²、Ｒ³、Ｒ⁴は炭素数１〜１８の直鎖状又は分岐状のアルキレン基である。）
を含有するポジ型レジスト組成物を用いた場合、露光後の加熱処理（ＰＥＢ）を行うことなしに現像を行うことで、２０〜１２０μｍといった厚膜のレジストパターン（レジスト層）の形成が可能であり、現像後、レジストパターンをマスクにして金属メッキを行うことで基板上にメッキパターンを効果的に形成し得ることを見出した。このレジストパターン及びメッキパターン形成方法は、今まで化学増幅型レジストパターン形成時に必須とされてきたＰＥＢ工程を行わずに為しえるものであるため、プロセス時間の短縮が期待できる。更にＰＥＢ工程そのものが不要なため、一般的に化学増幅型レジスト材料の問題点とされている露光からＰＥＢ工程までの引き置き（ＰＥＢ Ｄｅｌａｙ）時間の変動による仕上がり寸法や形状の変動がない。従って、レジストパターン及びメッキパターンの形状を安定させることが期待できる。 As a result of intensive studies to achieve the above object, the present inventor has the following (A) to (C) components (A) having a repeating unit represented by the following general formula (1), wherein R ^{The unit in which 1} is a group represented by the following general formula (2) is 25 to 40 mol%, the p-hydroxystyrene unit in which R ¹ is a hydrogen atom is 60 to 75 mol%, and the molecular weight distribution is 1. A polymer that is 5-2.0,
(B) a photoacid generator,
(C) Solvent

(In the formula, R ¹ represents a hydrogen atom or a functional group represented by the following general formula (2).)

(Wherein R ² and R ³ each independently represent a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms. R ⁴ is a straight chain having 1 to 30 carbon atoms. A chain, branched or cyclic alkyl group, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, R ² and R ³ , R ² and R ^4, or R ³ and R ⁴ are mutually A carbon atom or a carbon atom and an oxygen atom to which these are bonded may be combined to form a ring. When a ring is formed, R ² , R ³ and R ⁴ involved in the formation of the ring have 1 to 18 carbon atoms. A linear or branched alkylene group.)
In the case of using a positive resist composition containing, it is possible to form a thick resist pattern (resist layer) of 20 to 120 μm by performing development without performing post-exposure heat treatment (PEB). It has been found that after development, a plating pattern can be effectively formed on a substrate by performing metal plating using the resist pattern as a mask. Since this resist pattern and plating pattern forming method can be performed without performing the PEB process that has been essential at the time of forming a chemically amplified resist pattern, it can be expected to shorten the process time. Further, since the PEB process itself is unnecessary, there is no change in the finished size and shape due to the change in the PEB delay time from exposure to PEB process, which is generally regarded as a problem of the chemically amplified resist material. Therefore, it can be expected that the shapes of the resist pattern and the plating pattern are stabilized.

  In addition to the above, the present resist pattern and plating pattern forming method can form a pattern with high sensitivity, shape perpendicularity, and high resolution, and further includes a step of forming a metal plating layer. The present invention has been confirmed by confirming that this is a pattern forming method having crack resistance during or after the plating process.

（式中、Ｒ¹は水素原子又は下記一般式（２）で示される官能基を示す。）

（式中、Ｒ²、Ｒ³は、互いに独立して、水素原子又は炭素数１〜６の直鎖状、分岐状又は環状のアルキル基を示す。Ｒ⁴は、炭素数１〜３０の直鎖状、分岐状又は環状のアルキル基、炭素数６〜２０のアリール基又は炭素数７〜２０のアラルキル基を示す。Ｒ²とＲ³、Ｒ²とＲ⁴又はＲ³とＲ⁴は互いに結合してこれらが結合する炭素原子又は炭素原子と酸素原子と共に環を形成してもよく、環を形成する場合、環の形成に関与するＲ²、Ｒ³、Ｒ⁴は炭素数１〜１８の直鎖状又は分岐状のアルキレン基である。）
（２）フォトマスクを介して波長３６５〜４３６ｎｍの光で露光する工程、
（３）露光後の加熱処理は行わずに、現像液にて現像する工程
を含むレジストパターンの形成方法。
請求項２：
レジスト層の膜厚が４０〜１００μｍである請求項１記載のレジストパターンの形成方法。
請求項３：
基板が、銅、金、ニッケル及びパーマロイから選ばれる金属がスパッタリングにより形成されたシリコン基板である請求項１又は２記載のレジストパターンの形成方法。
請求項４：
バンプ形成に用いる請求項１〜３のいずれか１項記載のレジストパターンの形成方法。
請求項５：
上記請求項１〜３のいずれか１項記載のレジストパターンの形成方法における現像工程後、レジストパターンをマスクとして基板上に金属メッキ層を形成する工程を含むメッキパターンの形成方法。 Accordingly, the present invention provides the following resist pattern forming method and plating pattern forming method.
Claim 1:
(1) A step of applying a resist composition containing the following components (A) to (C) to a substrate to form a resist layer having a thickness of 20 to 120 μm ;
(A) It has a repeating unit represented by the following general formula (1), in which R ¹ is a group represented by the following general formula (2), 25 to 35 mol%, and R ¹ is a hydrogen atom. A polymer having a p-hydroxystyrene unit of 65 to 75 mol% and a molecular weight distribution of 1.5 to 2.0,
(B) a photoacid generator,
(C) Solvent

(In the formula, R ¹ represents a hydrogen atom or a functional group represented by the following general formula (2).)

(Wherein R ² and R ³ each independently represent a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms. R ⁴ is a straight chain having 1 to 30 carbon atoms. A chain, branched or cyclic alkyl group, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, R ² and R ³ , R ² and R ^4, or R ³ and R ⁴ are mutually A carbon atom or a carbon atom and an oxygen atom to which these are bonded may be combined to form a ring. When a ring is formed, R ² , R ³ and R ⁴ involved in the formation of the ring have 1 to 18 carbon atoms. A linear or branched alkylene group.)
(2) a step of exposing with light having a wavelength of 365 to 436 nm through a photomask;
(3) A method for forming a resist pattern including a step of developing with a developer without performing a heat treatment after exposure.
Claim 2:
The method for forming a resist pattern according to claim 1, wherein the thickness of the resist layer is 40 to 100 μm.
Claim 3:
3. The method of forming a resist pattern according to claim 1, wherein the substrate is a silicon substrate formed by sputtering a metal selected from copper, gold, nickel and permalloy.
Claim 4:
The method for forming a resist pattern according to claim 1, which is used for forming a bump.
Claim 5:
A method for forming a plating pattern comprising a step of forming a metal plating layer on a substrate using the resist pattern as a mask after the developing step in the method for forming a resist pattern according to any one of claims 1 to 3 .

  By using the resist pattern forming method of the present invention, the process time can be shortened, and the finished dimensions and shape can be stabilized without being influenced by PEB Delay. And the resist pattern obtained by the resist pattern formation method of this invention is excellent in high sensitivity, high perpendicularity, and high resolution, and is used suitably when forming a bump.

  In the resist pattern forming method of the present invention, a resist composition containing the following polymer is applied to a substrate, exposed to light with a wavelength of 365 to 436 nm through a photomask, and developed without performing a heat treatment after exposure. It is carried out by developing with a liquid. Then, a plating pattern is formed on the substrate using the obtained resist pattern.

（式中、Ｒ¹は水素原子又は下記一般式（２）で示される官能基を示す。）

（式中、Ｒ²、Ｒ³は、互いに独立して、水素原子又は炭素数１〜６の直鎖状、分岐状又は環状のアルキル基を示す。Ｒ⁴は、炭素数１〜３０の直鎖状、分岐状又は環状のアルキル基、炭素数６〜２０のアリール基又は炭素数７〜２０のアラルキル基を示す。Ｒ²とＲ³、Ｒ²とＲ⁴又はＲ³とＲ⁴は互いに結合してこれらが結合する炭素原子又は炭素原子と酸素原子と共に環を形成してもよく、環を形成する場合、環の形成に関与するＲ²、Ｒ³、Ｒ⁴は炭素数１〜１８の直鎖状又は分岐状のアルキレン基である。） Specifically, the base polymer in the resist composition used in the present invention is a group in which R ¹ is a group represented by the following general formula (2) among polymers having a repeating unit represented by the following general formula (1). The unit is 25 to 40 mol%, the p-hydroxystyrene unit in which R ¹ is a hydrogen atom is 60 to 75 mol%, and the molecular weight distribution is 1.50 to 2.00.

(In the formula, R ¹ represents a hydrogen atom or a functional group represented by the following general formula (2).)

(Wherein R ² and R ³ each independently represent a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms. R ⁴ is a straight chain having 1 to 30 carbon atoms. A chain, branched or cyclic alkyl group, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, R ² and R ³ , R ² and R ^4, or R ³ and R ⁴ are mutually A carbon atom or a carbon atom and an oxygen atom to which these are bonded may be combined to form a ring. When a ring is formed, R ² , R ³ and R ⁴ involved in the formation of the ring have 1 to 18 carbon atoms. A linear or branched alkylene group.)

In the general formula (2), examples of the linear, branched or cyclic alkyl group having 1 to 6 carbon atoms of R ² and R ³ include, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, n -Butyl group, isobutyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, hexyl group, cyclopentyl group, cyclohexyl group and the like.

Examples of the linear, branched or cyclic alkyl group having 1 to 30 carbon atoms of R ⁴ include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, n -Pentyl group, isopentyl group, neopentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-decyl group, n-dodecyl group, n-hexyl group, palmityl group, n-stearyl group, cyclopropyl Group, cholesteryl group and the like. Examples of the aryl group having 6 to 20 carbon atoms include phenyl group, tolyl group, ethylphenyl group, propylphenyl group, dimethylphenyl group, methylethylphenyl group, naphthyl group, furyl group, and biphenyl group. Examples of the aralkyl group having 7 to 20 carbon atoms include a benzyl group, a methylbenzyl group, a propylbenzyl group, and a dimethylbenzyl group.

The base polymer of the resist composition used in the resist pattern forming method of the present invention is a unit in which R ¹ is a group represented by the above general formula (2) among the polymers having a repeating unit represented by the above general formula (1). Is a polymer in which the p-hydroxystyrene unit in which R ¹ is a hydrogen atom is 60 to 75 mol%, particularly 65 to 75 mol%. If R ¹ is a polymer having 25 to 40 mol% of the unit represented by the general formula (2) and 60 to 75 mol% of p-hydroxystyrene unit in which R ¹ is a hydrogen atom, the remaining film From the viewpoint of rate, the unexposed part has a sufficient resistance to the developer, and from the viewpoint of resolution, the acid labile group is eliminated by the acid generated by exposure, which is preferable.

  The base polymer of the resist composition used in the method for forming a resist pattern of the present invention comprises polyhydroxystyrene in an acid catalyst, for example, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, dihydro It can be obtained by addition reaction of alkenyl ether compounds such as furan and dihydropyran. Furthermore, as a reaction condition for introducing an acid labile group, an aprotic polar solvent such as dimethylformamide, tetrahydrofuran, 1,4-dioxane or the like can be used alone or in admixture of two or more. As the catalyst acid, hydrochloric acid, sulfuric acid, trifluoromethanesulfonic acid, p-toluenesulfonic acid, methanesulfonic acid and the like can be used.

  The weight average molecular weight in terms of polystyrene by gel permeation chromatography (GPC) of the base polymer of the resist composition used in the resist pattern forming method of the present invention is 10,000 to 50,000, particularly 20,000 to 40,000. The molecular weight distribution needs to be 1.5 to 2.0, particularly 1.6 to 1.9. A polymer having a molecular weight distribution of 1.5 to 2.0 is preferable from the viewpoint of exposure margin and resolution. The molecular weight distribution of polyhydroxystyrene which is a raw material for the acetalized polymer is also preferably 1.5 to 2.0, particularly 1.6 to 1.9.

  The addition amount of the base polymer of the resist composition used in the resist pattern forming method of the present invention is preferably 25.0 to 55.0 mass%, particularly 35.0 to 45.0 mass% in the resist composition. . If the addition amount of the base polymer is in the range of 25.0 to 55.0% by mass, it is preferable from the viewpoint of easy viscosity for thick film resist formation during coating.

Next, the photoacid generator used in the resist composition used in the resist pattern forming method of the present invention will be described. Specific examples of the photoacid generator include, for example, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium trifluoromethanesulfonate (p-tert-butoxyphenyl), trimethylsulfonium trifluoromethanesulfonate, trimethylsulfonium p-toluenesulfonate, Onium salts such as dimethylphenylsulfonium p-toluenesulfonate, dicyclohexylphenylsulfonium trifluoromethanesulfonate; bis (benzenesulfonyl) diazomethane, bis (p-toluenesulfonyl) diazomethane, bis (xylenesulfonyl) diazomethane, bis (cyclohexylsulfonyl) ) Diazomethane derivatives such as diazomethane and bis (cyclopentylsulfonyl) diazomethane; α- (benzenesulfonate) Muokishiimino) -4-oxime sulfonate derivatives such as methylphenyl acetonitrile;
Further, (5- (4-methylphenyl) sulfonyloxyimino-5H-thiophen-2-ylidene)-(2-methylphenyl) acetonitrile, (5- (4- (4-methylphenylsulfonyloxy) phenylsulfonyloxy Imino) -5H-thiophen-2-ylidene)-(2-methylphenyl) -iminosulfonates such as acetonitrile, 2-methyl-2 [(4-methylphenyl) sulfonyl] -1-[(4-methylthio) phenyl] -1-propane etc. are mentioned. Among these, oxime sulfonates, imino sulfonates, and the like are preferably used. The addition amount of the photoacid generator of the resist composition used in the resist pattern forming method of the present invention is 0.1 to 10.0 parts by mass, particularly 0.3 to 5.0% by mass in the resist composition. Is preferred. If the addition amount of a photo-acid generator is 0.1-10.0 mass%, it is preferable from a viewpoint of high sensitivity and high resolution.

  Next, as a solvent used in the resist composition used in the resist pattern forming method of the present invention, any solvent that has sufficient solubility and good coating properties with respect to the base polymer and the photoacid generator can be used. It can be used without particular limitation.

  For example, ketones such as cyclohexanone and cyclopentanone; alcohols such as 1-methoxy-2-propanol and 1-ethoxy-2-propanol; ethers such as propylene glycol monomethyl ether and ethylene glycol monomethyl ether; propylene glycol monomethyl ether Examples thereof include esters such as acetate, ethyl lactate, and γ-butyrolactone, and these can be used alone or in combination of two or more.

  Of these, ethyl lactate, cyclohexanone, cyclopentanone, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, γ-butyrolactone and mixed solvents thereof are particularly preferable. The addition amount of the solvent of the resist composition used in the resist pattern forming method of the present invention is preferably 30.0 to 70.0% by mass, particularly 40.0 to 60.0% by mass in the resist composition. If the addition amount of a solvent is 30.0-70.0 mass% in a resist composition, it is preferable from a viewpoint of an easy viscosity of thick film resist formation at the time of application | coating.

  In addition to the above components, various additive components may be further blended in the resist composition used in the resist pattern forming method of the present invention.

  As one of the additive components, for example, a surfactant conventionally used for improving the coating property can be added. As the surfactant, nonionic ones are preferable, and examples thereof include fluorine-based surfactants, specifically perfluoroalkyl polyoxyethylene ethanol, fluorinated alkyl esters, fluorine-containing organosiloxane compounds, and the like.

  As these, commercially available products can be used. For example, Florard “FC-4430” (manufactured by Sumitomo 3M Limited), MegaFuck “F-8151” (manufactured by DIC Corporation), “X-70” -093 "(manufactured by Shin-Etsu Chemical Co., Ltd.). Among these, Fluorard “FC-4430” (manufactured by Sumitomo 3M Limited) and “X-70-093” (manufactured by Shin-Etsu Chemical Co., Ltd.) are preferable.

  In addition, a nitrogen-containing compound can be added as another additive component in order to improve environmental stability, pattern shape, or stability over time. Nitrogen-containing compounds include amines, particularly secondary or tertiary aliphatic amines. Examples of the secondary or tertiary amine include diethylamine, di-n-propylamine, diethanolamine, trimethylamine, triethylamine, tri-n-propylamine, triethanolamine, tripropanolamine and the like.

  Next, the resist pattern forming method of the present invention will be described. The above-described resist composition based on a polymer is applied to a substrate by a known method such as a dipping method, a spin coating method, or a roll coating method, and is pre-baked with a heating device such as a hot plate or an oven.

In this case, although it depends on the type of plating after pattern formation, generally, a substrate such as silicon on which a metal such as copper, gold, nickel or permalloy is formed by sputtering or the like is preferably used.
Moreover, it is preferable that the resist film formed on this board | substrate is 20-120 micrometers, especially 40-100 micrometers in thickness.

Next, using a radiation generator such as a stepper or mask aligner, light of various wavelengths, for example, broadband including g-line, i-line, g-line and i-line, or ultraviolet light such as KrF excimer laser. Exposure. The exposure dose is 100 to 1000 mJ / cm ² , 100 to 1000 mJ / cm ² , 100 to 1000 mJ / cm ² , 50 to 50 g for broadband including g-line, i-line, g-line and i-line, or KrF excimer laser. 500 mJ / cm ² is preferable from the viewpoint of exposure margin and throughput.

  In the resist pattern forming method of the present invention, heat treatment after exposure is unnecessary. Rather, heat treatment is not preferable because it causes a reduction in exposure margin. The time from exposure to development is preferably within 72 hours. If 72 hours are passed, the resolution may be lowered. As the developer, a known alkaline developer solvent represented by an aqueous solution of tetramethylammonium hydroxide or the like is used. The development can be performed by a normal method, for example, by dipping a pattern formed product. The development time is preferably 100 to 600 seconds from the viewpoint of throughput when a 2.38 mass% tetramethylammonium hydroxide aqueous solution is used as the developer. Thereafter, washing, rinsing, drying, and the like are performed as necessary to obtain a desired pattern. Such a resist pattern forming method can shorten the heat treatment process time after the exposure, and has no influence of PEB Delay, and can stabilize the finished dimensions and shape. The resist pattern thus obtained has a crack resistance during or after the plating process when forming a plating pattern including a process of forming a metal plating layer, and is suitable for forming bumps. Used for.

  Furthermore, the plating pattern formation method of this invention is demonstrated. Specifically, using the resist pattern formed by the above resist pattern forming method as a mask, a conductor pattern is deposited and formed by an electrolytic plating method or an electroless plating method by a conventional method, and then the resist pattern is removed. . Examples of electrolytic plating and electroless copper plating include electrolytic copper plating, electroless copper plating, electrolytic iron-nickel plating, and electrolytic gold plating, and plating can be performed using a known plating bath and plating conditions. The plating thickness is generally formed at 80 to 100% of the resist pattern film thickness. For example, after the seed layer is copper and a resist pattern having a thickness of 50 μm is formed thereon, a copper plating layer having a thickness of 40 to 50 μm can be formed by electrolytic copper plating. Also, two or more kinds of plating layers can be formed in an overlapping manner. For example, the seed layer is copper, a resist pattern having a thickness of 50 μm is formed thereon, a copper plating of 30 to 40 μm is formed by electrolytic copper plating, and further, by electrolytic nickel plating or electroless Sn-Ag plating. There is no particular limitation as long as it can be formed, such as forming a nickel layer or Sn—Ag layer having a plating thickness of 10 to 20 μm.

  EXAMPLES Hereinafter, although a synthesis example, an Example, and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.

[Synthesis Example 1]
Synthesis of acetalized polymer 1 A 1 L three-necked flask equipped with a thermometer, a stirrer, and a condenser was charged with 50.0 g of polyhydroxystyrene (0.42 mol, weight average molecular weight (GPC polystyrene standard) 13.5 × 10 ³ , molecular weight). Distribution (Mw / Mn) 1.33), 200 g of tetrahydrofuran were charged, and 1.0 g (0.01 mol) of methanesulfonic acid was added. Next, 6.6 g (0.09 mol) of ethyl vinyl ether was added dropwise with stirring while keeping the internal temperature at 10 ° C. or lower with stirring with ice cooling to 10 ° C. or lower. After dropping, the mixture was reacted at room temperature for 2 hours, and then 1.0 g (0.01 mol) of triethylamine was added to complete the reaction. The reaction solution was transferred to a 1 L eggplant flask, tetrahydrofuran was distilled off with a rotary evaporator under reduced pressure at room temperature, 300 g of methyl isobutyl ketone and 250 mL of 0.01N acetic acid aqueous solution were added, and the reaction solution was washed with water. After repeating this washing operation three times in total, the organic layer was separated and concentrated with a rotary evaporator, and further the solvent was exchanged with propylene glycol monomethyl ether acetate to obtain 115.7 g of a polymer 1 propylene glycol monomethyl ether acetate solution (solid content). 48.5%).
The acetal substitution rate of this acetalized polymer 1 was calculated to be 20.2 mol% from the result of ¹³ C-NMR, and the molecular weight distribution (Mw / Mn) was 1.35 from the result of GPC measurement.

[Synthesis Example 2]
Synthesis of acetalized polymer 2 Into a 1 L three-necked flask equipped with a stirrer and a condenser, 50.0 g of polyhydroxystyrene (0.42 mol, weight average molecular weight (GPC polystyrene standard) 18.7 × 10 ³ , molecular weight) Distribution (Mw / Mn) 1.73), 200 g of tetrahydrofuran were charged, and 1.0 g (0.01 mol) of methanesulfonic acid was added. Next, 9.9 g (0.11 mol) of ethyl-1-propenyl ether was added dropwise with stirring while keeping the internal temperature at 10 ° C. or lower with stirring while ice-cooling to 10 ° C. or lower and stirring. In the same manner as in Example 1, 118.8 g of a propylene glycol monomethyl ether acetate solution of polymer 2 (solid content: 49.0%) was obtained.
The acetal substitution rate of this acetalized polymer 2 was calculated to be 25.1 mol% from the result of ¹³ C-NMR, and the molecular weight distribution (Mw / Mn) was 1.80 from the result of GPC measurement.

[Synthesis Example 3]
Synthesis of acetalized polymer 3 A 1 L three-necked flask equipped with a thermometer, a stirrer and a condenser was charged with 50.0 g of polyhydroxystyrene (0.42 mol, weight average molecular weight (GPC polystyrene standard) 25.6 × 10 ³ , molecular weight). Distribution (Mw / Mn) 2.28), 200 g of tetrahydrofuran were charged, and 1.0 g (0.01 mol) of methanesulfonic acid was added. Next, the reaction was performed in the same manner as in Synthesis Example 1 except that 8.6 g (0.12 mol) of ethyl vinyl ether was added dropwise with stirring while maintaining the internal temperature at 10 ° C. or lower with stirring. Thus, 119.4 g of a propylene glycol monomethyl ether acetate solution of polymer 3 (solid content: 48.0%) was obtained.
The acetal substitution rate of this acetalized polymer 3 was calculated to be 26.5 mol% from the result of ¹³ C-NMR, and the molecular weight distribution (Mw / Mn) was 2.30 from the result of GPC measurement.

[Synthesis Example 4]
Synthesis of acetalized polymer 4 Into a 1 L three-necked flask equipped with a stirrer and a condenser, 50.0 g of polyhydroxystyrene (0.42 mol, weight average molecular weight (GPC polystyrene standard) 29.7 × 10 ³ , molecular weight) Distribution (Mw / Mn) 1.50), 200 g of tetrahydrofuran were charged, and 1.0 g (0.01 mol) of methanesulfonic acid was added. Next, 14.6 g (0.17 mol) of 3,4-dihydro-2H-pyran was added dropwise with stirring while keeping the internal temperature at 10 ° C. or lower while stirring and cooling to 10 ° C. or lower with stirring. Proceeding in the same manner as in Synthesis Example 1, 125.0 g of a propylene glycol monomethyl ether acetate solution of polymer 4 (solid content 50.0%) was obtained.
The acetal substitution rate of this acetalized polymer 4 was calculated to be 37.3 mol% from the result of ¹³ C-NMR, and the molecular weight distribution (Mw / Mn) was 1.60 from the result of GPC measurement.

[Synthesis Example 5]
Synthesis of acetalized polymer 5 A 1 L three-necked flask equipped with a thermometer, a stirrer, and a condenser was charged with 50.0 g of polyhydroxystyrene (0.42 mol, weight average molecular weight (GPC polystyrene standard) 48.1 × 10 ³ , molecular weight). Distribution (Mw / Mn) 1.74), 200 g of tetrahydrofuran were charged, and 1.0 g (0.01 mol) of methanesulfonic acid was added. Next, Synthesis Example 1 was carried out except that 17.7 g (0.21 mol) of ethyl-1-propenyl ether was added dropwise with stirring while keeping the internal temperature at 10 ° C. or lower with stirring while ice-cooling to 10 ° C. or lower and stirring. In the same manner as above, 130.8 g of a propylene glycol monomethyl ether acetate solution of polymer 5 (solid content: 49.0%) was obtained.
The acetal substitution rate of this acetalized polymer 5 was calculated to be 45.8 mol% from the result of ¹³ C-NMR, and the molecular weight distribution (Mw / Mn) was 1.80 from the result of GPC measurement.

[Synthesis Example 6]
Synthesis of acetalized polymer 6 A 1 L three-necked flask equipped with a thermometer, a stirrer, and a condenser was charged with 50.0 g of polyhydroxystyrene (0.42 mol, weight average molecular weight (GPC polystyrene standard) 31.4 × 10 ³ , molecular weight). Distribution (Mw / Mn) 1.64), 200 g of tetrahydrofuran were charged, and 1.0 g (0.01 mol) of methanesulfonic acid was added. Next, the reaction was performed in the same manner as in Synthesis Example 1 except that 9.9 g (0.14 mol) of ethyl vinyl ether was added dropwise with stirring while maintaining the internal temperature at 10 ° C. or lower with stirring. Thus, 122.0 g of propylene glycol monomethyl ether acetate solution of polymer 6 (solid content: 47.3%) was obtained.
The acetal substitution rate of this acetalized polymer 6 was calculated to be 29.8 mol% from the result of ¹³ C-NMR, and the molecular weight distribution (Mw / Mn) was 1.67 from the result of GPC measurement.

[Example 1]
40.8 g of a propylene glycol monomethyl ether acetate solution of polymer 2 obtained in Synthesis Example 2 was dissolved in 3.67 g of cyclopentanone, and 4-methoxy-α-[[[[(4-methylphenyl)] was used as a photoacid generator. [Sulfonyl] -oxy] imino] benzeneacetonitrile (0.20 g) and surfactant X-70-093 (0.01 g) were mixed and dissolved, and then filtered through a membrane filter having a pore size of 0.5 μm to obtain a resist solution. Prepared.
Next, after pre-wetting propylene glycol monomethyl ether acetate on a substrate on which a copper sputtered film of about 200 nanometers was formed on a 6-inch silicon wafer, the resist solution was applied by a spinner, and then heated at 120 ° C. / Pre-baking was performed for 600 seconds to form a resist film having a thickness of 50 μm. Further, patterning exposure was performed using an i-line stepper (NSR-1755i7A manufactured by Nikon, NA = 0.5), and a paddle of 480 seconds was used with a developer of 2.38% by mass of tetramethylammonium hydroxide without heat treatment after exposure. After developing and rinsing with pure water, the resist pattern was observed with Hitachi SEM: S-4100. In addition, 10-100 μm line & space (L & S) pattern is observed, and resolution is improved by its sensitivity, pattern side wall verticality, presence or absence of resist residue (scum) in space part and minimum resolution dimension (line & space). Judgment was regarded as resist pattern evaluation.

  After forming the resist pattern, using a dry etching apparatus (manufactured by Nidec Anelva: DEM-451), the resist pattern and the substrate surface are ashed with oxygen plasma at 100 W for 30 seconds, and then in 3% sulfuric acid water for 30 seconds. Soaked. Then, it was immersed in a copper plating solution (Nippon Electroplating Engineers Co., Ltd .: Microfab Cu200), and was subjected to copper plating by flowing a constant current at 25 ° C. for 30 minutes, thereby laminating copper having a film thickness of about 40 microns. . Next, the surface after plating was washed with pure water and blown with nitrogen to dry the plated surface, and then immersed in acetone for 5 minutes to remove the resist pattern. Then, after washing with isopropyl alcohol and blowing the nitrogen to dry the peeled surface, the plating pattern was evaluated by observing the plating pattern with an optical microscope and the SEM and judging its shape and perpendicularity.

[Example 2]
A resist solution was prepared in the same manner as in Example 1 except that 40.0 g of the propylene glycol monomethyl ether acetate solution of polymer 4 obtained in Synthesis Example 4 was dissolved in 3.53 g of cyclopentanone. Subsequently, the plating pattern was evaluated.

[Example 3]
42.3 g of the propylene glycol monomethyl ether acetate solution of polymer 6 obtained in Synthesis Example 6 was dissolved in 3.93 g of cyclopentanone, and [5- (4- (4-methylphenylsulfonyloxy) phenyl] was used as a photoacid generator. Except that 0.20 g of sulfonyloxyimino) -5H-thiophen-2-ylidene]-(2-methylphenyl) -acetonitrile and 0.01 g of surfactant X-70-093 were mixed and dissolved. A resist solution was prepared in the same manner as 1 to form a resist film. Further, a resist pattern was formed in the same manner as in Example 1 except that patterning exposure was performed using a g-line stepper (NSR-TFH-1, manufactured by Nikon, NA = 0.22), and a resist pattern evaluation and then a plating pattern evaluation were performed. It was.

[Comparative Example 1]
41.2 g of the propylene glycol monomethyl ether acetate solution of polymer 1 obtained in Synthesis Example 1 was dissolved in 3.75 g of cyclopentanone, and [5- (4- (4-methylphenylsulfonyloxy) phenyl] was used as a photoacid generator. Except that 0.20 g of sulfonyloxyimino) -5H-thiophen-2-ylidene]-(2-methylphenyl) -acetonitrile and 0.01 g of surfactant X-70-093 were mixed and dissolved. A resist solution was prepared in the same manner as in 1.
Next, after pre-wetting propylene glycol monomethyl ether acetate on a substrate on which a copper sputtered film of about 200 nanometers was formed on a 6-inch silicon wafer, the resist solution was applied by a spinner, and then heated at 120 ° C. / Pre-baking was performed for 600 seconds to form a resist film having a thickness of 50 μm. Further, a resist pattern was formed in the same manner as in Example 1 except that patterning exposure was performed using a g-line stepper (NSR-TFH-1, manufactured by Nikon, NA = 0.22), and a resist pattern evaluation and then a plating pattern evaluation were performed. It was.

[Comparative Example 2]
A resist solution was prepared in the same manner as in Example 1 except that 41.7 g of the propylene glycol monomethyl ether acetate solution of polymer 3 obtained in Synthesis Example 3 was dissolved in 3.82 g of cyclopentanone. Subsequently, the plating pattern was evaluated.

[Comparative Example 3]
A resist solution was prepared in the same manner as in Example 1 except that 40.8 g of the propylene glycol monomethyl ether acetate solution of polymer 5 obtained in Synthesis Example 5 was dissolved in 3.67 g of cyclopentanone. Subsequently, the plating pattern was evaluated.

  Table 1 shows the resist pattern evaluation results and the plating pattern evaluation results.

１）浮き有：残渣が完全に除去できないため、メッキパターンが基板から浮いたように観察された。

1) Floating existence: Since the residue could not be completely removed, the plating pattern was observed to float from the substrate.

Claims (5)

(1) A step of applying a resist composition containing the following components (A) to (C) to a substrate to form a resist layer having a thickness of 20 to 120 μm ;
(A) It has a repeating unit represented by the following general formula (1), in which R ¹ is a group represented by the following general formula (2), 25 to 35 mol%, and R ¹ is a hydrogen atom. A polymer having a p-hydroxystyrene unit of 65 to 75 mol% and a molecular weight distribution of 1.5 to 2.0,
(B) a photoacid generator,
(C) Solvent

(In the formula, R ¹ represents a hydrogen atom or a functional group represented by the following general formula (2).)

(Wherein R ² and R ³ each independently represent a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms. R ⁴ is a straight chain having 1 to 30 carbon atoms. A chain, branched or cyclic alkyl group, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, R ² and R ³ , R ² and R ^4, or R ³ and R ⁴ are mutually A carbon atom or a carbon atom and an oxygen atom to which these are bonded may be combined to form a ring. When a ring is formed, R ² , R ³ and R ⁴ involved in the formation of the ring have 1 to 18 carbon atoms. A linear or branched alkylene group.)
(2) a step of exposing with light having a wavelength of 365 to 436 nm through a photomask;
(3) A method for forming a resist pattern including a step of developing with a developer without performing a heat treatment after exposure. The method for forming a resist pattern according to claim 1, wherein the thickness of the resist layer is 40 to 100 μm. 3. The method of forming a resist pattern according to claim 1, wherein the substrate is a silicon substrate formed by sputtering a metal selected from copper, gold, nickel and permalloy. The method for forming a resist pattern according to claim 1, which is used for forming a bump. A method for forming a plating pattern comprising a step of forming a metal plating layer on a substrate using the resist pattern as a mask after the developing step in the method for forming a resist pattern according to any one of claims 1 to 3 .