JP2008250200A - Photosensitive resin composition and method for manufacturing resist pattern using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive resin composition from which a fine resist pattern with a large film thickness and a high aspect ratio can be formed without generating variance in the pattern dimension by improving coating uniformity, and to provide a device for MEMS (microelectro-mechanical system) in which the resist pattern is incorporated as a component. <P>SOLUTION: The photosensitive resin composition having improved coating uniformity and giving a fine resist pattern with a large film thickness and a high aspect ratio is obtained by adding a silicone-based surfactant into a photosensitive resin composition containing a polyfunctional epoxy resin and a cation polymerization initiator. The device for a MEMS includes the above resist pattern as a component. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a photosensitive resin composition and a method for producing a resist pattern using the same, and in particular, a fine resist having excellent coating uniformity and high film thickness and high aspect ratio without causing variations in pattern dimensions. The present invention relates to a photosensitive resin composition capable of forming a pattern, a method for forming a resist pattern using the same, and a device for MEMS incorporating a resist pattern formed by using the forming method as a component.

  In recent years, MEMS (Micro Electro Mechanical System), which is attracting attention as a mass-productivity system that integrates fine parts in the same chip using semiconductor manufacturing technology and realizes high performance and high integration, Expansion to various fields such as automobiles, consumer devices, medical care, and biotechnology is expected. On the other hand, demands for downsizing in these fields are increasing, and development of a photosensitive resin composition capable of forming a fine resist pattern having a high film thickness and a high aspect ratio is required.

  However, a conventional photosensitive resin composition containing a novolac resin and a photoacid generator diazonaphthoquinone cannot obtain a profile having a high aspect ratio under a high film thickness. The diazonaphthoquinone photoacid generator exhibits high absorption for near-ultraviolet light used for exposure, and the resulting exposure pattern differs greatly between the top and bottom of the thick film, resulting in a tapered resin profile. This is because of distortion.

  On the other hand, a photosensitive resin composition containing an epoxy resin and an acid generator has been proposed as a photosensitive resin composition capable of forming a fine resist pattern with a high aspect ratio. Specifically, a photosensitive resin composition comprising an acid generator such as an epoxy-functional novolak resin or a triarylsulfonium salt and a diluent capable of reacting with an epoxy reactive group is disclosed (for example, see Patent Document 1). ). Also disclosed is a photosensitive resin composition comprising a multifunctional bisphenol A formaldehyde-novolak resin, an acid generator triphenylsulfonium hexafluoroantimonate, and a cyclopentanone solvent, and capable of forming a thick film ( For example, see Patent Document 2).

On the other hand, in addition to the diazonaphthoquinone type photoacid generator, a photosensitive resin composition having high sensitivity and high resolution has been proposed. For example, a photosensitive resin composition using an aromatic sulfonium cationic polymerization initiator is disclosed (see Patent Documents 3 and 4). Moreover, the permanent film resist composition containing the cationic polymerization initiator which has absorption in the exposure light of 360 nm or more is disclosed (refer patent document 5).
Japanese Patent Publication No. 7-78628 US Pat. No. 6,391,523 JP 9-268205 A JP 2005-055865 A JP-A-10-097068

  However, the photosensitive resin composition in which the above cationic polymerization initiator is blended with the epoxy resin can be expected to improve the sensitivity, but the coating uniformity is not good. The coating uniformity is an important characteristic that greatly affects the transfer of the mask pattern. If the coating uniformity is poor, there is a problem in that the pattern dimensions vary.

  The present invention has been made in view of the problems as described above, and the object thereof is to improve the coating uniformity so that the pattern size does not vary, and the high film thickness and high aspect ratio are fine. It is providing the photosensitive resin composition which can form a resist pattern, and also the device for MEMS incorporating the said resist pattern as components.

  The inventors of the present invention have made extensive studies to solve the above problems. As a result, it was found that the above problems can be solved by adding a silicone-based surfactant to a photosensitive resin composition containing a polyfunctional epoxy resin and a cationic polymerization initiator, and the present invention has been completed. It was.

  That is, the present invention is a photosensitive resin composition comprising (a) a polyfunctional epoxy resin, (b) a cationic polymerization initiator, (c) a solvent, and (d) a surfactant, wherein (d) The component provides a photosensitive resin composition characterized by being a silicone-based surfactant. In addition, the photosensitive resin composition is applied on a support, dried, exposed to a predetermined pattern, and then developed to obtain a cured resin pattern having a predetermined shape by heat treatment. A method of forming a resist pattern is provided. Furthermore, a MEMS device incorporating a resist pattern formed using the resist pattern forming method as a component is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the photosensitive resin composition which is excellent in application | coating uniformity, and can form a fine resist pattern with a high film thickness and a high aspect ratio, without producing the variation in pattern dimension, and formation of a resist pattern using this It is possible to provide a MEMS device that incorporates a method and a resist pattern formed by using the forming method as a component.

  Hereinafter, embodiments of the present invention will be described in detail.

  The photosensitive resin composition according to the present invention contains (a) a polyfunctional epoxy resin, (b) a cationic polymerization initiator, (c) a solvent, and (d) a surfactant.

<(A) Polyfunctional epoxy resin>
As the (a) polyfunctional epoxy resin used in the photosensitive resin composition according to the present invention, any epoxy resin having an epoxy group sufficient for forming a thick resist pattern in one molecule may be used. It is not limited. Examples of such polyfunctional epoxy resins include polyfunctional phenol / novolak type epoxy resins, polyfunctional orthocresol novolac type epoxy resins, polyfunctional triphenyl type novolac type epoxy resins, polyfunctional bisphenol A novolac type epoxy resins and the like. . Of these, polyfunctional bisphenol A novolac type epoxy resins are preferably used. The functionality is preferably 5 or more. For example, “Epicoat 157S70” manufactured by Japan Epoxy Resin Co., Ltd. and “Epicron N-865” manufactured by Dainippon Ink & Chemicals, Inc. are commercially available and particularly preferably used. .

Said polyfunctional bisphenol A novolak-type epoxy resin is represented by the following general formula (a1).

The bisphenol A novolak type epoxy resin of the general formula (a1) may be a polymer of a bisphenol A type epoxy resin or a bisphenol A novolak type epoxy resin and an epoxy group-containing component. In formula (a1), R _{1 to} R ₆ are H or CH ₃ . n is 0 or an integer of 1-5.

  The softening point of the polyfunctional epoxy resin is not particularly limited as long as it is solid at room temperature. Usually, it is preferably about 50 ° C to about 100 ° C, more preferably about 60 ° C to about 80 ° C. .

  The content of the polyfunctional epoxy resin in the photosensitive resin composition is preferably 80% by mass to 99.9% by mass, and 92% by mass to 99.4% by mass in the total solid content. More preferred. As a result, a resist film having high sensitivity and appropriate hardness can be obtained when it is coated on the substrate.

<(B) Cationic polymerization initiator>
The cationic polymerization initiator (b) used in the photosensitive resin composition according to the present invention generates a cationic component upon irradiation with excimer lasers such as ultraviolet rays, far ultraviolet rays, KrF and ArF, X-rays, or electron beams. It is a compound whose cationic component can be a polymerization initiator.

（式（ｂ１）中、Ａは原子価ｍの硫黄原子又はヨウ素原子を表し、ｍは１又は２である。ｎは括弧内の構造の繰り返し単位数を表し、０〜３の整数である。ＲはＡに結合している有機基であり、炭素数６〜３０のアリール基、炭素数４〜３０の複素環基、炭素数１〜３０のアルキル基、炭素数２〜３０のアルケニル基、又は炭素数２〜３０のアルキニル基を表し、Ｒはアルキル、ヒドロキシ、アルコシキ、アルキルカルボニル、アリールカルボニル、アルコシキカルボニル、アリールオキシカルボニル、アリールチオカルボニル、アシロキシ、アリールチオ、アルキルチオ、アリール、複素環、アリールオキシ、アルキルスルフィニル、アリールスルフィニル、アルキルスルホニル、アリールスルホニル、アルキレンオキシ、アミノ、シアノ、ニトロの各基、及びハロゲンからなる群より選ばれる少なくとも１種の置換基で置換されていてもよい。Ｒの個数はｍ＋ｎ（ｍ−１）＋１であり、Ｒはそれぞれ互いに同じであっても異なっていてもよいが、Ｒの少なくとも１つ、更に好ましくはＲの全てが、前記置換基を有してもよい炭素数６〜３０のアリール基又は炭素数４〜３０の複素環基である。また、２個以上のＲが互いに直接、又は−Ｏ−、−Ｓ−、−ＳＯ−、−ＳＯ_２−、−ＮＨ−、−ＮＲ’−、−ＣＯ−、−ＣＯＯ−、−ＣＯＮＨ−、炭素数１〜３のアルキレン基若しくはフェニレン基を介して結合し、Ａを含む環構造を形成してもよい。Ｒ’は炭素数１〜５のアルキル基又は炭素数６〜１０のアリール基である。
Ｄは下記一般式（ｂ２）で表される構造であり、

式（ｂ２）中、Ｅは炭素数１〜８のアルキレン基、炭素数６〜２０のアリーレン基、又は炭素数８〜２０の複素環化合物の２価の基を表し、Ｅは炭素数１〜８のアルキル、炭素数１〜８のアルコキシ、炭素数６〜１０のアリール、ヒドロキシ、シアノ、ニトロの各基、及びハロゲンからなる群より選ばれる少なくとも１種で置換されていてもよい。ここで、複素環化合物の２価の基とは、複素環化合物の異なる２個の環炭素原子から、各々１個の水素原子を除いてできる２価の基をいう。Ｇは−Ｏ−、−Ｓ−、−ＳＯ−、−ＳＯ_２−、−ＮＨ−、−ＮＲ’−、−ＣＯ−、−ＣＯＯ−、−ＣＯＮＨ−、炭素数１〜３のアルキレン基、又はフェニレン基を表す。ａは０〜５の整数である。ａ＋１個のＥ及びａ個のＧはそれぞれ同一であっても異なっていてもよい。Ｒ’は前記のものと同じである。
Ｘ⁻はオニウムの対イオンである。その個数は１分子当たりｎ＋１であり、そのうち少なくとも１個は下記一般式（ｂ３）で表されるフッ素化アルキルフルオロリン酸アニオンであって、

残りは他のアニオンであってもよい。
式（ｂ３）中、Ｒｆは水素原子の８０％以上がフッ素原子で置換されたアルキル基を表す。ｂはその個数を示し、１〜５の整数である。ｂ個のＲｆはそれぞれ同一であっても異なっていてもよい。）
で表されるオニウムフッ素化アルキルフルオロリン酸塩を用いることができる。 Specifically, as the above (b) cationic polymerization initiator, the following general formula (b1):

(In the formula (b1), A represents a sulfur atom or iodine atom having a valence m, and m is 1 or 2. n represents the number of repeating units in the parenthesis, and is an integer of 0 to 3. R is an organic group bonded to A, an aryl group having 6 to 30 carbon atoms, a heterocyclic group having 4 to 30 carbon atoms, an alkyl group having 1 to 30 carbon atoms, an alkenyl group having 2 to 30 carbon atoms, Or an alkynyl group having 2 to 30 carbon atoms, wherein R is alkyl, hydroxy, alkoxy, alkylcarbonyl, arylcarbonyl, alkoxycarbonyl, aryloxycarbonyl, arylthiocarbonyl, acyloxy, arylthio, alkylthio, aryl, heterocycle, aryl Oxy, alkylsulfinyl, arylsulfinyl, alkylsulfonyl, arylsulfonyl, alkyleneoxy, amino, cyano Each of the nitro groups may be substituted with at least one substituent selected from the group consisting of halogen, and the number of R may be m + n (m−1) +1, and R may be the same as each other. It may be different, but at least one of R, more preferably all of R is an aryl group having 6 to 30 carbon atoms or a heterocyclic group having 4 to 30 carbon atoms, which may have the substituent. In addition, two or more R's may be directly selected from each other, or —O—, —S—, —SO—, —SO ₂ —, —NH—, —NR′—, —CO—, —COO—, —CONH—. May be bonded via an alkylene group having 1 to 3 carbon atoms or a phenylene group to form a ring structure containing A. R ′ is an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms. It is.
D is a structure represented by the following general formula (b2),

In formula (b2), E represents a divalent group of an alkylene group having 1 to 8 carbon atoms, an arylene group having 6 to 20 carbon atoms, or a heterocyclic compound having 8 to 20 carbon atoms, and E represents 1 to 1 carbon atoms. It may be substituted with at least one selected from the group consisting of 8 alkyls, C 1-8 alkoxys, C 6-10 aryls, hydroxy, cyano, nitro groups, and halogens. Here, the divalent group of the heterocyclic compound refers to a divalent group formed by removing one hydrogen atom from each of two different ring carbon atoms of the heterocyclic compound. G is -O -, - S -, - SO -, - SO 2 -, - NH -, - NR '-, - CO -, - COO -, - CONH-, alkylene group having 1 to 3 carbon atoms, or Represents a phenylene group. a is an integer of 0-5. a + 1 E and a G may be the same or different. R ′ is the same as described above.
X ⁻ is a counter ion of onium. The number is n + 1 per molecule, at least one of which is a fluorinated alkyl fluorophosphate anion represented by the following general formula (b3),

The rest may be other anions.
In the formula (b3), Rf represents an alkyl group in which 80% or more of hydrogen atoms are substituted with fluorine atoms. b shows the number and is an integer of 1-5. The b Rf's may be the same or different. )
The onium fluorinated alkyl fluorophosphate represented by these can be used.

  Preferable specific examples of the onium ion of the general formula (b1) include triphenylsulfonium, tri-p-tolylsulfonium, 4- (phenylthio) phenyldiphenylsulfonium, bis [4- (diphenylsulfonio) phenyl] sulfide, bis [4- {bis [4- (2-hydroxyethoxy) phenyl] sulfonio} phenyl] sulfide, bis {4- [bis (4-fluorophenyl) sulfonio] phenyl} sulfide, 4- (4-benzoyl-2-chlorophenyl) Thio) phenylbis (4-fluorophenyl) sulfonium, 4- (4-benzoylphenylthio) phenyldiphenylsulfonium, 7-isopropyl-9-oxo-10-thia-9,10-dihydroanthracen-2-yldi-p- Tolylsulfonium, 7- Sopropyl-9-oxo-10-thia-9,10-dihydroanthracen-2-yldiphenylsulfonium, 2-[(diphenyl) sulfonio] thioxanthone, 4- [4- (4-tert-butylbenzoyl) phenylthio] phenyldi- p-tolylsulfonium, 4- (4-benzoylphenylthio) phenyldiphenylsulfonium, diphenylphenacylsulfonium, 4-hydroxyphenylmethylbenzylsulfonium, 2-naphthylmethyl (1-ethoxycarbonyl) ethylsulfonium, 4-hydroxyphenylmethylphena Silsulfonium, octadecylmethylphenacylsulfonium, diphenyliodonium, di-p-tolyliodonium, bis (4-dodecylphenyl) iodonium, bis (4-methoxyphenyl) Nyl) iodonium, (4-octyloxyphenyl) phenyliodonium, bis (4-decyloxy) phenyliodonium, 4- (2-hydroxytetradecyloxy) phenylphenyliodonium, 4-isopropylphenyl (p-tolyl) iodonium, or 4 -Isobutylphenyl (p-tolyl) iodonium.

  The anion component of the onium fluorinated alkyl fluorophosphate has at least one fluorinated alkyl fluorophosphate anion represented by the general formula (b3). That is, the remaining anion component may be another anion.

  In the fluorinated alkylfluorophosphate anion represented by the general formula (b3), Rf represents an alkyl group substituted with a fluorine atom, preferably having 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms. . Specific examples of the alkyl group include linear alkyl groups such as methyl, ethyl, propyl, butyl, pentyl and octyl; branched alkyl groups such as isopropyl, isobutyl, sec-butyl and tert-butyl; and cyclopropyl, cyclobutyl and cyclopentyl. And the ratio of the hydrogen atom of the alkyl group substituted by a fluorine atom is usually 80% or more, preferably 90% or more, and more preferably 100%. When the fluorine atom substitution rate is 80% or more, the cationic polymerization initiating ability of the onium fluorinated alkyl fluorophosphate represented by the general formula (b1) is improved.

Particularly preferred Rf is a linear or branched perfluoroalkyl group having 1 to 4 carbon atoms and a fluorine atom substitution rate of 100%. Specific examples include CF ₃ , CF ₃ CF ₂ , (CF _{3 ) 2 CF, CF 3 CF 2} CF 2, CF 3 CF 2 CF 2 CF 2, (CF 3) 2 CFCF 2, CF 3 CF 2 (CF 3) CF, include _{(CF 3)} 3 C. The number b of Rf is an integer of 1 to 5, preferably 2 to 4, particularly preferably 2 or 3.

Specific examples of preferred fluorinated alkyl fluorophosphate anions include [(CF ₃ CF ₂ ) ₂ PF ₄ ] ⁻ , [(CF ₃ CF ₂ ) ₃ PF ₃ ] ⁻ , [((CF ₃ ) ₂ CF) _2. PF ₄ ] ⁻ , [((CF ₃ ) ₂ CF) ₃ PF ₃ ] ⁻ , [(CF ₃ CF ₂ CF ₂ ) ₂ PF ₄ ] ⁻ , [(CF ₃ CF ₂ CF ₂ ) ₃ PF ₃ ] ⁻ , [((CF ₃ ) ₂ CFCF ₂ ) ₂ PF ₄ ] ⁻ , [((CF ₃ ) ₂ CFCF ₂ ) ₃ PF ₃ ] ⁻ , [(CF ₃ CF ₂ CF ₂ CF ₂ ) ₂ PF ₄ ] ⁻ , or [(CF ₃ CF ₂ CF ₂ ) ₃ PF ₃ ] ⁻ , and among these, [(CF ₃ CF ₂ ) ₃ PF ₃ ] ⁻ , [(CF ₃ CF ₂ CF ₂ ) ₃ PF ₃ ] ⁻ , _{[((CF 3) 2 CF} ) 3 PF 3 ^{_{-, [((CF 3)}} 2 CF) 2 PF 4] -, [((CF 3) 2 CFCF 2) 3 PF 3] -, or _{[((CF 3) 2 CFCF} 2) 2 PF 4] - is Particularly preferred.

（式（ｂ４）におけるｎは、１〜１０の整数であり、より好ましくは、１〜５の整数である。） Of the onium fluorinated alkyl fluorophosphates represented by the general formula (b1), diphenyl [4- (phenylthio) phenyl] sulfonium trifluorotrisfluoroalkyl phosphate represented by the following general formula (b4): [4- (Phenylthio) phenyl] sulfonium hexafluorophosphate is particularly preferably used.

(N in the formula (b4) is an integer of 1 to 10, more preferably an integer of 1 to 5.)

  It is preferable that content of the said (b) cationic polymerization initiator is 0.5-20 mass parts with respect to 100 mass parts of said (a) polyfunctional epoxy resins. (B) When the content of the cationic polymerization initiator is 0.5 parts by mass or more, sufficient sensitivity can be obtained. On the other hand, when the amount is less than 20 parts by mass, the permanent film characteristics are improved. Specifically, water absorption and thermal decomposition temperature characteristics are improved.

In the case of conventional phosphorous (PF ₆ ⁻ ) and boron (BF ₄ ⁻ ) cationic polymerization initiators, in order to obtain permanent film properties equivalent to those of a highly sensitive antimony (SbF ₆ ⁻ ) cationic polymerization initiator, antimony The exposure amount was 10 times or more that of the system. On the other hand, according to the cationic polymerization initiator represented by the general formulas (b1) to (b3), the permanent film resist pattern can be formed with the same sensitivity as that of the antimony system. Furthermore, it has excellent solubility in the photosensitive resin composition and has good storage stability.

Moreover, the compound represented by the following general formula (b5) can be used as said (b) cationic polymerization initiator.

In the formula (b5), X ₁ and X ₂ represent a hydrogen atom, a halogen atom, an oxygen atom, a hydrocarbon group that may contain a halogen atom, or an alkoxy group to which a substituent may be bonded, and are the same as each other But it can be different. Further, among these X ₁ and X ₂ , a halogen atom is preferable, and a fluorine atom is more preferable among the halogen atoms. In the formula (b5), Y represents a hydrogen atom, a halogen atom, an oxygen atom, a hydrocarbon group that may contain a halogen atom, or an alkoxy group to which a substituent may be bonded. Among these, Y is preferably a halogen atom, and more preferably a chlorine atom among the halogen atoms.

  Examples of the cationic polymerization initiator represented by the general formula (b5) include 4- (4-benzoylphenylthio) phenyldiphenylsulfonium hexafluoroantimonate, 4- (4-benzoylphenylthio) phenylbis (4-hydroxy). Ethyloxyphenyl) sulfonium hexafluoroantimonate, 4- (4-benzoylphenylthio) phenylbis (4-fluorophenyl) sulfonium hexafluoroantimonate, 4- (4-benzoylphenylthio) phenylbis (4-chlorophenyl) sulfonium Hexafluoroantimonate, 4- {4- (3-chlorobenzoyl) phenylthio} phenylbis (4-fluorophenyl) sulfonium hexafluoroantimonate, 4- (4-benzoylphenylthio) Nylbis (4-methylphenyl) sulfonium hexafluoroantimonate, 4- (4-benzoylphenylthio) phenylbis (4-hydroxyethylphenyl) sulfonium hexafluoroantimonate, 4- {4- (4-hydroxyethyloxybenzoyl) Phenylthio} phenylbis (4-fluorophenyl) sulfonium hexafluoroantimonate, 4- {4- (4-hydroxyethyloxybenzoyl) phenylthio} phenyldiphenylsulfonium hexafluoroantimonate, 4- {4- (4-hydroxyethyloxy) Benzoyl) phenylthio} phenylbis (4-hydroxyethyloxyphenyl) sulfonium hexafluoroantimonate, 4- (4-benzoylphenylthio) phenylbis (4 Methoxyethoxyphenyl) sulfonium hexafluoroantimonate, 4- {4- (3-methoxybenzoyl) phenylthio} phenyldiphenylsulfonium hexafluoroantimonate, 4- {4- (3-methoxycarbonylbenzoyl) phenylthio} phenyldiphenylsulfonium hexafluoro Antimonate, 4- {4- (2-hydroxymethylbenzoyl) phenylthio} phenyldiphenylsulfonium hexafluoroantimonate, 4- {4- (4-methylbenzoyl) phenylthio} phenylbis (4-fluorophenyl) sulfonium hexafluoroantimony 4- {4- (4-methoxybenzoyl) phenylthio} phenylbis (4-fluorophenyl) sulfonium hexafluoroantimonate 4- {4- (4-fluorobenzoyl) phenylthio} phenylbis (4-fluorophenyl) sulfonium hexafluoroantimonate, 4- {4- (2-methoxycarbonylbenzoyl) phenylthio} phenylbis (4-fluorophenyl) ) Sulfonium hexafluoroantimonate.

Among these compounds, 4- (4-benzoylphenylthio) phenyldiphenylsulfonium hexafluoroantimonate, 4- (4-benzoylphenylthio) phenylbis (4-hydroxyethyloxyphenyl) sulfonium hexafluoroantimonate, 4- (4-benzoylphenylthio) phenylbis (4-fluorophenyl) sulfonium hexafluoroantimonate, 4- (4-benzoylphenylthio) phenylbis (4-chlorophenyl) sulfonium hexafluoroantimonate, 4- {4- (3 -Chlorobenzoyl) phenylthio} phenylbis (4-fluorophenyl) sulfonium hexafluoroantimonate, [4- {4- (2-chlorobenzoyl) phenylthio} phenylbis (4-fluoro )) Sulfonium hexafluoroantimonate], [4- (phenylthio) phenyl] sulfonium hexafluoroantimonate is more preferable, and [4- (phenylthio) phenyl] sulfonium hexafluoroantimonate is represented by the following general formula (b6). Asahi Denka Kogyo Co., Ltd. “Adekaoptomer SP-172” [4- {4- (2-chlorobenzoyl) phenylthio} phenylbis (4-fluorophenyl) sulfonium hexafluoroantimonate] Is most preferred.

  The composition ratio of the cationic polymerization initiator represented by the general formula (b6) is preferably 0.1% by mass to 10% by mass, and more preferably 0.5% by mass to 5% by mass. If it is 0.1% by mass or more, the curing time by radiation exposure of the photosensitive resin composition is shortened, and if it is 10% by mass or less, development of the photosensitive resin composition is easy.

  In the photosensitive resin composition which concerns on this invention, the onium fluorinated alkyl fluorophosphate represented by the said general formula (b1) and the compound represented by the said general formula (b5) are used respectively independently. Or two or more of them may be used in combination. Moreover, you may use together with another conventionally well-known cationic polymerization initiator. The ratio in the case of using two or more kinds in combination is arbitrary and is not particularly limited. Although the use ratio in the case of using other cationic polymerization initiators together may be arbitrary, it is usually represented by the onium fluorinated alkyl fluorophosphate represented by the general formula (b1) and / or the general formula (b5). The other cationic polymerization initiator is 10 to 900 parts by mass, preferably 25 to 400 parts by mass with respect to 100 parts by mass of the total amount of the compounds to be produced.

<(C) Solvent>
The (c) solvent used for the photosensitive resin composition according to the present invention is not particularly limited, and a conventionally known solvent can be used. Examples thereof include γ-butyrolactone, propylene carbonate, propylene glycol monomethyl ether acetate, methyl isobutyl ketone, butyl acetate, methyl amyl ketone, 2-heptanone, ethyl acetate, and methyl ethyl ketone.

  Of the above solvents, in the case of a liquid resist, γ-butyrolactone and propylene carbonate are preferred from the viewpoint of reacting and being incorporated into the resist film. In the case of a dry film, wettability and surface tension with a base film. From this viewpoint, propylene glycol monomethyl ether acetate, methyl isobutyl ketone, butyl acetate, and methyl amyl ketone are preferably used.

<(D) Surfactant>
The surfactant (d) used in the photosensitive resin composition according to the present invention is a silicone-based surfactant. The silicone-based surfactant has polydimethylsiloxane as a basic structure, and examples thereof include anionic, cationic, nonionic and amphoteric ones. Silicone surfactants are roughly classified into unmodified silicones and modified silicones. Examples of modified silicones include sulfonic acid modification, carboxyl modification, ammonium salt modification, N-alkylsulfobetaine modification, polyether modification, alkylaralkyl polyether modification, epoxy polyether modification, alcohol modification, fluorine modification, amino modification, and mercapto modification. In addition to modified silicones such as epoxy modification, allyl modification, polyester modification, α-methylstyrene modification, alkyl modification, and phenyl modification, reactive silicones modified with reactive groups such as acrylic and isocyanate can be used.

  Among the silicone surfactants, at least one selected from the group consisting of an unmodified silicone, a polyether-modified silicone, a polyester-modified silicone, an alkyl-modified silicone, an aralkyl-modified silicone, and a reactive silicone Preferably used. Examples of the polyether-modified silicone include a polyether-modified silicone compound having at least one functional group capable of radical polymerization and a polyether-modified silicone compound having no functional group capable of radical polymerization.

  Conventionally, it is well known to add a surfactant to a photosensitive resin composition. For example, anionic surfactants such as fatty acid salts and alkyl sulfate ester salts, nonionic surfactants such as polyoxyethylene alkyl ether and polyoxyethylene alkyl allyl ether, alkylamine salts, quaternary ammonium salts, It is known to add a cationic surfactant such as alkylbetaine or an amphoteric surfactant to the photosensitive resin composition (see JP 2001-240728 A). However, this publication does not clearly describe the addition of a surfactant from the viewpoint of improving the coating uniformity of the photosensitive resin composition, but also completely describes the silicone-based surfactant used in the present invention. It has not been. In this respect, the present invention improves the coating uniformity of the photosensitive resin composition and avoids variations in pattern dimensions by adding a silicone-based surfactant different from the conventional one.

  Specifically, silicone surfactant “Paintad M” (trade name) manufactured by Toray Dow Corning, silicone surfactants “Topica K1000”, “Topica K2000”, and “Topica K5000” manufactured by Takachiho Sangyo Co., Ltd. (All trade names), polyether modified silicone surfactant “XL-121” (trade name) manufactured by Clariant, polyester modified silicone surfactant “BYK-310” (trade name) manufactured by BYK Chemie Preferably used. Among these, when a silicone-based surfactant “Paintad M” (trade name) manufactured by Toray Dow Corning Co., Ltd. is added to the photosensitive resin composition, the most excellent coating uniformity is obtained, so that it is particularly preferably used. .

  It is preferable that content of the said (d) component is 0.01 mass part-0.2 mass part with respect to 100 mass parts of (a) component. When the content of the component (d) is less than 0.2 parts by mass, the surfactant can be dissolved. Moreover, when there is more content of (d) component than 0.01 mass part, the improvement of application | coating uniformity is obtained. More preferably, it is 0.03 mass part-0.1 mass part.

<(E) Sensitizer>
The photosensitive resin composition according to the present invention may contain (a) an aromatic polycyclic compound having at least two substituents capable of crosslinking with the polyfunctional epoxy resin (a) as a sensitizer. Good. Such a sensitization function of the aromatic polycyclic compound can further increase the sensitivity of the photosensitive resin composition. In addition, since it has two or more crosslinkable substituents, the crosslink density of the polyfunctional epoxy resin can be improved, the film itself made of the photosensitive resin layer can be densified, and the photosensitive resin layer can be increased in hardness and reduced. Can absorb water. Furthermore, since it has a plurality of aromatic rings, the photosensitive resin layer can have a high Tg, a high hardness, and a low coefficient of thermal expansion.

  (A) Examples of the substituent capable of crosslinking with the polyfunctional epoxy resin include a hydroxyl group, a carboxyl group, and an amino group. Of these, aromatic polycyclic compounds such as naphthalene compounds, dinaphthalene compounds, anthracene compounds, and phenanthroline compounds having at least two substituents are preferably used. Of these, naphthalene compounds and anthracene compounds are particularly preferred.

  Specific examples of the naphthalene compound and the anthracene compound include 1-naphthol, β-naphthol, α-naphthol methyl ether, α-naphthol ethyl ether, 1,2-dihydroxynaphthalene, 1,3-dihydroxynaphthalene, 1,4-dihydroxy. Naphthalene, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 1,8-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene 9,10-dihydroxyanthracene and the like.

  It is preferable that content of the said naphthol type sensitizer is 1-50 mass parts with respect to 100 mass parts of said (a) polyfunctional epoxy resins. By setting it as such a composition ratio, a desired effect is acquired, without deteriorating a resist pattern shape.

<(F) Polymer linear bifunctional epoxy resin>
The photosensitive resin composition according to the present invention may contain (f) a polymer linear bifunctional epoxy resin in order to improve the film formability. Specifically, bisphenol A type epoxy or bisphenol F type epoxy is polymerized and preferably has an average molecular weight of 2,000 to 7,000, more preferably 3,000 to 5,000. When the average molecular weight is 2,000 or more, the film formability can be improved, and when it is less than 7,000, it is compatible with the polyfunctional epoxy resin (a). For example, “Epicoat 1009” (average molecular weight 3750) manufactured by Japan Epoxy Resin Co., Ltd. is preferably used.

<Other ingredients>
From the viewpoint of improving the flexibility of the photosensitive resin composition before curing without reducing the physical properties after curing of the photosensitive resin composition, the photosensitive resin composition according to the present invention contains an oxetane derivative or an epoxy derivative. You may make it contain. Furthermore, if desired, a miscible additive such as an additive resin for improving pattern performance, a plasticizer, a stabilizer, a colorant, a coupling agent, and the like may be contained as appropriate. it can.

<Method for forming resist pattern>
As a usage form of the photosensitive resin composition according to the present invention, it may be used by coating on a support, or both surfaces may be protected with a protective film to form a dry film, and this may be applied to the support. Good. When supplying as a dry film, as a protective film, it is preferable to use the polymer film in any one of a polyethylene terephthalate film, a polypropylene film, and a polyethylene film. If it supplies as a dry film, the application | coating on a support body and a drying process can be skipped, and the pattern formation using the photosensitive resin composition of this invention will be attained more simply.

  That is, the photosensitive resin composition according to the present invention is applied to a support, for example, a substrate such as a silicon wafer, using a spin coater or the like, dried, and then subjected to pattern exposure and development with a developer to use the support. A good resin pattern faithful to the mask pattern can be formed without depending on the body. Also, a good resin pattern faithful to the mask pattern can be formed by pasting the above-mentioned dry film on the support, removing the protective film, and pattern-exposing and developing with a developer. Furthermore, a good resin pattern that is faithful to the mask pattern can be formed by pasting the above-mentioned dry film on a support and pattern exposure, and then removing the protective film and developing with a developer. Therefore, for example, in the molding of electronic devices such as MEMS, even if a dry film is provided on the resist pattern and further resist patterning is required, the dry film does not bend and good micro resin molding is performed. realizable.

<Devices for MEMS>
The MEMS device of the present invention is configured with a resist pattern having a thickness of 30 μm formed using the photosensitive resin composition of the present invention as a partition. Such MEMS devices are used as components such as SAW filters, BAW filters, gyro sensors, image sensors, electronic paper, inkjet heads, biochips, sealants, and the like.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

<Examples 1-4, Comparative Examples 1-2>
A photosensitive resin composition containing a polyfunctional epoxy resin, a cationic polymerization initiator, a sensitizer, a solvent, a surfactant, and the like was obtained according to the formulation shown in Table 1 (unit: parts by mass).

  These photosensitive resin compositions were applied onto a silicon wafer with a spin coater and then dried to obtain a photosensitive resin composition layer having a thickness of 30 μm. This photosensitive resin composition layer was pre-baked at 130 ° C. for 10 minutes. After pre-baking, pattern exposure (soft contact, GHI line) was performed using PLA-501F (contact aligner: manufactured by Canon), and post-exposure heating (PEB) was performed at 90 ° C. for 5 minutes using a hot plate. Then, the development processing for 8 minutes was performed by the immersion method using PGMEA (propylene glycol monomethyl ether acetate). Next, the resin pattern after development was post-baked for 1 hour at 200 ° C. using an oven together with the substrate to obtain a cured resin pattern on the substrate.

<Evaluation of coating uniformity>
For the photoresist with a film thickness of 30 μm obtained by the above-mentioned spin coating, the edge peripheral part 5 mm is cut and the coating film uniformity is calculated from the average value of the film thickness at nine points on the wafer surface. Was evaluated. The evaluation results are shown in Table 1.

(A): Multifunctional bisphenol A novolac type epoxy resin: JER157S70 (manufactured by Japan Epoxy Resin Co., Ltd.)
(B): Cationic polymerization initiator: Diphenyl [4- (phenylthio) phenyl] sulfonium hexafluoroantimonate (C): α-naphthol (D): Ethyl lactate (E-1): Silicone surfactant: Paintad M (Toray Dow Corning)
(E-2): Polyether-modified silicone surfactant: XL-121 (manufactured by Clariant)
(E-3): Polyester-modified silicone surfactant: BYK-310 (manufactured by Big Chemie)
(E-4): Quaternary ammonium salt surfactant: DDMAO (manufactured by Lion Akzo Corporation)

  As shown in Table 1, in Examples 1 to 4, the coefficient of variation in film thickness was 5% or less, whereas in Comparative Examples 1 and 2, it was 5% or more. From this result, it was confirmed that the variation of the pattern dimension can be suppressed because the present embodiment has less variation in film thickness and excellent coating uniformity as compared with the comparative example.

Claims (11)

A photosensitive resin composition comprising (a) a polyfunctional epoxy resin, (b) a cationic polymerization initiator, (c) a solvent, and (d) a surfactant,
The photosensitive resin composition, wherein the component (d) is a silicone-based surfactant.   The silicone surfactant is at least one selected from the group consisting of an unmodified silicone, a polyether-modified silicone, a polyester-modified silicone, an alkyl-modified silicone, an aralkyl-modified silicone, and a reactive silicone. The photosensitive resin composition according to claim 1.   The photosensitive resin composition according to claim 1, wherein the component (d) is contained in an amount of 0.01 to 0.2 parts by mass with respect to 100 parts by mass of the component (a).   The said (a) component is polyfunctional bisphenol A novolak-type epoxy resin, The photosensitive resin composition in any one of Claim 1 to 3 characterized by the above-mentioned.   The component (b) is diphenyl [4- (phenylthio) phenyl] sulfonium trifluorotrisfluoroalkyl phosphate, [4- (phenylthio) phenyl] sulfonium hexafluorophosphate, [4- (phenylthio) phenyl] sulfonium hexafluoro. Antimonate and at least one compound selected from compounds represented by [4- {4- (2-chlorobenzoyl) phenylthio} phenylbis (4-fluorophenyl) sulfonium hexafluoroantimonate] The photosensitive resin composition according to any one of claims 1 to 4.   Furthermore, (e) a sensitizer is contained, The photosensitive resin composition in any one of Claim 1 to 5 characterized by the above-mentioned.   A dry film comprising a protective film formed on both sides of a layer formed from the photosensitive resin composition according to claim 1.   The photosensitive resin composition according to any one of claims 1 to 6 is coated on a support, dried, exposed to a predetermined pattern, and then developed to heat the resin pattern to obtain a predetermined shape. A method for forming a resist pattern, comprising obtaining a cured resin pattern.   The protective film of the dry film according to claim 7 is removed, and this is attached to a support and exposed to a predetermined pattern, and then the resin pattern obtained by development is heat-treated to obtain a cured resin having a predetermined shape A method for forming a resist pattern, comprising obtaining a pattern.   The dry film according to claim 7 is attached on a support and exposed to a predetermined pattern, and then the protective film of the dry film is removed and developed, and the resulting resin pattern is heated to obtain a predetermined shape. A method for forming a resist pattern, comprising obtaining a cured resin pattern.   A device for MEMS incorporating a resist pattern formed by using the method for forming a resist pattern according to claim 8 as a component.