JP2007101944A - Photosensitive resin composition and laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive resin composition which exhibits satisfactory sensitivity to an exposure light source having a wavelength of 405 nm in a composition of which transmittance at 405 nm has been controlled, and which has good resolution and adhesion and can be developed with an alkaline aqueous solution, a photosensitive resin laminate using the photosensitive resin composition, a method for forming a resist pattern on a substrate using the photosensitive resin laminate, and uses of the resist pattern. <P>SOLUTION: The photosensitive resin composition contains (a) 20-90 mass% of a thermoplastic copolymer containing an α,β-unsaturated carboxyl group-containing monomer as a copolymerized component and having an acid equivalent of 100-600 and a weight average molecular weight of 5,000-500,000, (b) 5-75 mass% of an addition polymerizable monomer having at least one terminal ethylenically unsaturated group, and (c) 0.01-30 mass% of a photopolymerization initiator. A photosensitive resin layer obtained by applying and drying the photosensitive resin composition on a support has a transmittance at 405 nm of 15-40% in terms of a thickness of 40 μm. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a photosensitive resin composition that can be developed with an alkaline aqueous solution, a photosensitive resin laminate in which the photosensitive resin composition is laminated on a support, and a resist pattern on a substrate using the photosensitive resin laminate. The present invention relates to a method for forming the resist pattern and an application of the resist pattern. More specifically, the manufacture of printed wiring boards, the manufacture of flexible printed wiring boards, the manufacture of lead frames for mounting IC chips (hereinafter referred to as lead frames), metal foil precision processing such as metal mask manufacturing, and BGA (ball grid array) , Manufacturing of semiconductor packages such as CSP (chip size package), manufacture of tape substrates represented by TAB (Tape Automated Bonding) and COF (Chip On Film: a semiconductor IC mounted on a film-like fine wiring board), Sensation that gives a resist pattern suitable as a protective mask member when manufacturing a substrate by manufacturing semiconductor bumps, manufacturing members such as ITO electrodes, address electrodes, or electromagnetic wave shields in the field of flat panel displays, and sandblasting About RESIN composition.

Conventionally, printed wiring boards are manufactured by a photolithography method. The photolithographic method is a method in which a photosensitive resin composition is applied onto a substrate, pattern exposure is performed to polymerize and cure an exposed portion of the photosensitive resin composition, and an unexposed portion is removed with a developing solution. A method of forming a conductor pattern on a substrate by forming a resist pattern, performing etching or plating treatment to form a conductor pattern, and peeling and removing the resist pattern from the substrate.
In the photolithography method described above, when a layer made of a photosensitive resin composition (hereinafter referred to as “photosensitive resin layer”) is laminated on a substrate, a photoresist solution is applied to the substrate and dried, or Any method of laminating a photosensitive resin laminate (hereinafter referred to as “dry film resist”) in which a support, a photosensitive resin layer, and, if necessary, a protective layer are sequentially laminated, is used. In the production of printed wiring boards, the latter dry film resist is often used.

A method for producing a printed wiring board using the dry film resist will be briefly described below. First, when there is a protective layer such as a polyethylene film, it is peeled off from the photosensitive resin layer. Next, the photosensitive resin layer and the support are laminated on a substrate such as a copper-clad laminate using a laminator so that the substrate, the photosensitive resin layer, and the support are in this order. Next, the exposed portion is polymerized and cured by exposing the photosensitive resin layer with ultraviolet rays such as i rays (365 nm) emitted from an ultrahigh pressure mercury lamp through a photomask having a wiring pattern. Next, the support made of polyethylene terephthalate or the like is peeled off. Next, a non-exposed portion of the photosensitive resin layer is dissolved or dispersed and removed by a developing solution such as an aqueous solution having weak alkalinity to form a resist pattern on the substrate. Next, a known etching process or pattern plating process is performed using the formed resist pattern as a protective mask. Finally, the resist pattern is peeled from the substrate to produce a substrate having a conductor pattern, that is, a printed wiring board. With the recent miniaturization of wiring intervals in printed wiring boards, the demand for high resolution is increasing for dry film resists. On the other hand, exposure methods are also diversified according to applications, and maskless exposure that does not require a photomask such as direct drawing by a laser has been rapidly spreading in recent years. As a light source for maskless exposure, light having a wavelength of 350 to 410 nm is often used, and in particular, h-rays (405 nm) are often used recently. By introducing this direct drawing method, it is possible to greatly reduce the cost represented by the total elimination of mask costs. Further, the yield can be greatly improved by improving the mask position accuracy with respect to the expansion and contraction of the substrate and by automating the exposure operation. Since various circuit patterns can be formed only by digitally processing the mask data, the delivery time can be shortened.

  However, it is generally known that in laser exposure, the curing of a dry film resist is weaker than in a conventional exposure method. This not only causes a decrease in resolution and adhesion to the substrate, but also degrades basic performance as a dry film resist, such as resist shape deterioration, etchant penetration, and plating resistance deterioration. End up. These phenomena are particularly prominent with respect to h-line having a wavelength of 405 nm. The conventional dry film resist is designed for i-line having a wavelength of 355 nm, and therefore the factor is that the transmittance at 405 nm is very high. There has been a strong demand for a resist that sufficiently absorbs h-rays and exhibits good resolution and adhesion to a substrate. Patent Document 1 describes that the sensitivity and image quality are improved by introducing a pyrazoline-type compound into the composition and absorbing 405 nm laser light, but it does not describe the dependency on the transmittance. .

JP-A-2005-215142

  The present invention is a photosensitive resin composition that has sufficient sensitivity to an exposure light source having a wavelength of 405 nm in a composition with controlled transmittance at 405 nm, and that can be developed with an alkaline aqueous solution with good resolution and adhesion. And a photosensitive resin laminate using the photosensitive resin composition, a method of forming a resist pattern on a substrate using the photosensitive resin laminate, and use of the resist pattern .

The present inventor has studied to solve the above problems, and found that the above problems can be solved by using a photosensitive resin composition containing a photopolymerizable monomer having a specific structure, and has led to the present invention. .
That is, this application provides the following invention.
(1) (a) Thermoplastic copolymer containing an α, β-unsaturated carboxyl group-containing monomer as a copolymerization component and having an acid equivalent of 100 to 600 and a weight average molecular weight of 5,000 to 500,000: 20 to 90 mass %, (B) addition polymerizable monomer having at least one terminal ethylenically unsaturated group: 5 to 75% by mass, and (c) photopolymerization initiator: 0.01 to 30% by mass. The transmittance at 405 nm of the photosensitive resin layer obtained by applying the photosensitive resin composition on a support and drying it is 15 to 40% in terms of a film thickness of 40 μm. A photosensitive resin composition.
(2) (b) The photosensitive resin composition as described in (1), which contains a compound represented by the following general formula (I) as an addition polymerizable monomer.

（式中、Ｒ₁及びＲ₂はＨまたはＣＨ₃であり、これらは同一であっても相違してもよい。また、ＡおよびＢは、炭素数が２〜４個のアルキレン基であり、それぞれ同一であっても異なっていてもよい。ｍ１、ｍ２、ｎ１およびｎ２は０または正の整数であり、ｍ１、ｍ２、ｎ１およびｎ２の合計は、２〜４０である。）

(In the formula, R ₁ and R ₂ are H or CH ₃ , which may be the same or different. A and B are alkylene groups having 2 to 4 carbon atoms; Each may be the same or different, m1, m2, n1 and n2 are 0 or a positive integer, and the sum of m1, m2, n1 and n2 is 2 to 40.)

(3) A photosensitive resin laminate obtained by laminating the photosensitive resin composition according to (1) or (2) on a support.
(4) A resist pattern forming method comprising sequentially performing a lamination step, an exposure step, and a development step for forming a photosensitive resin layer on the substrate using the photosensitive resin laminate according to (3).
(5) The resist pattern forming method according to (4), wherein in the exposure step, direct drawing exposure is performed.
(6) A method for producing a printed wiring board by etching or plating a substrate on which a resist pattern is formed by the method according to (4) or (5).
(7) A method for producing a lead frame by etching a substrate on which a resist pattern is formed by the method according to (4) or (5).
(8) A method for manufacturing a semiconductor package, including a step of etching or plating a substrate on which a resist pattern is formed by the method according to (4) or (5).
(9) A method in which a substrate on which a resist pattern is formed by the method according to (4) or (5) is processed by a sandblasting process.

  According to the present invention, in a composition with controlled transmittance at 405 nm, the photosensitive resin exhibits sufficient sensitivity to an exposure light source having a wavelength of 405 nm and can be developed with an alkaline aqueous solution having good resolution and adhesion. A composition, a photosensitive resin laminate using the photosensitive resin composition, a method of forming a resist pattern on a substrate using the photosensitive resin laminate, and a use of the resist pattern can be provided.

The present invention will be specifically described below.
<Transmissivity>
The present invention relates to a dry film resist having a transmittance of 15 to 40% at a wavelength of 405 nm (h line) of a laser beam when the thickness is 40 μm. Transmittance is 40
If it is at least%, the activity with respect to the laser beam is not sufficient, the sensitivity is lowered, and as a result, the productivity is lowered. On the other hand, when the transmittance is 15% or less, the laser beam cannot reach the bottom of the dry film, and the adhesion with the substrate is lost. For these reasons, the transmittance at 405 nm is 15 to 40%, more preferably 20 to 35%.
In the present invention, in order to set the transmittance to 15 to 40%, for example, the following (c) type and combination of photopolymerization initiators are appropriately selected, and the blending amount is 0.01 to 30% by weight. This can be achieved by appropriately selecting the range.

<Photosensitive resin composition>
The photosensitive resin composition of the present invention comprises (a) a thermoplastic copolymer containing an α, β-unsaturated carboxyl group-containing monomer as a copolymerization component and having an acid equivalent of 100 to 600 and a weight average molecular weight of 5,000 to 500,000. Polymer: 20 to 90% by mass, (b) Addition polymerizable monomer having at least one terminal ethylenically unsaturated group: 5 to 75% by mass, (c) Photopolymerization initiator: 0.01 to 30% by mass It contains.

(A) Thermoplastic copolymer In the photosensitive resin composition of the present invention, (a) as the thermoplastic copolymer, an acid equivalent containing an α, β-unsaturated carboxyl group-containing monomer as a copolymer component. And having a weight average molecular weight of 5,000 to 500,000.
The carboxyl group in the thermoplastic copolymer is necessary for the photosensitive resin composition to have developability and releasability with respect to a developer and a release solution made of an alkaline aqueous solution.
The acid equivalent is preferably 100 to 600, more preferably 300 to 450. From the viewpoint of ensuring compatibility with the coating solvent or other components in the composition, (b) addition polymerizable monomer described later, and 600 from the viewpoint of maintaining developability and releasability. It is as follows. Here, an acid equivalent means the mass (gram) of the thermoplastic copolymer which has a 1 equivalent carboxyl group in it. The acid equivalent is measured by potentiometric titration with a 0.1 mol / L NaOH aqueous solution using a Hiranuma Reporting Titrator (COM-555).

The weight average molecular weight is preferably 5,000 to 500,000. It is 5,000 or more from the viewpoint of maintaining the thickness of the dry film resist uniformly and obtaining resistance to the developer, and is 500,000 or less from the viewpoint of maintaining developability. More preferably, the weight average molecular weight is 20,000 to 100,000. The weight average molecular weight in this case is a weight average molecular weight measured by gel permeation chromatography (GPC) using a polystyrene calibration curve. The weight average molecular weight can be measured using gel permeation chromatography manufactured by JASCO Corporation under the following conditions.
Differential refractometer: RI-1530,
Pump: PU-1580,
Degasser: DG-980-50,
Column oven: CO-1560,
Column: KF-8025, KF-806M × 2, KF-807, in order
Eluent: THF

  The thermoplastic copolymer is a copolymer composed of at least one first monomer described later, or at least one second monomer described later with at least one first monomer. A copolymer comprising the above is preferred. The first monomer is a monomer containing an α, β-unsaturated carboxyl group in the molecule. Examples include (meth) acrylic acid, fumaric acid, cinnamic acid, crotonic acid, itaconic acid, maleic anhydride, and maleic acid half ester. Among these, (meth) acrylic acid is particularly preferable.

The second monomer is a non-acidic monomer having at least one polymerizable unsaturated group in the molecule. For example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, tert-butyl ( Meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, benzyl (meth) acrylate, vinyl alcohol esters (meth) acrylonitrile , Styrene, and polymerizable styrene derivatives. Of these, methyl (meth) acrylate, n-butyl (meth) acrylate, styrene, and benzyl (meth) acrylate are particularly preferable.
The amount of the thermoplastic polymer contained in the photosensitive resin composition of the present invention is in the range of 20 to 90% by mass, and preferably in the range of 25 to 70% by mass. This amount is 20% by mass or more from the viewpoint of maintaining alkali developability, and is 90% by mass or less from the viewpoint that the resist pattern formed by exposure sufficiently exhibits the performance as a resist.

（式中、Ｒ₁及びＲ₂はＨまたはＣＨ₃であり、これらは同一であっても相違してもよい。また、ＡおよびＢは、炭素数が２〜４個のアルキレン基であり、それぞれ同一であっても異なっていてもよい。ｍ１、ｍ２、ｎ１およびｎ２は０または正の整数であり、ｍ１、ｍ２、ｎ１およびｎ２の合計は、２〜４０である。） (B) Addition polymerizable monomer The (b) addition polymerizable monomer used in the photosensitive resin composition of the present invention contains a compound represented by the following general formula (I) from the viewpoint of resolution and adhesion. It is desirable.

(In the formula, R ₁ and R ₂ are H or CH ₃ , which may be the same or different. A and B are alkylene groups having 2 to 4 carbon atoms; Each may be the same or different, m1, m2, n1 and n2 are 0 or a positive integer, and the sum of m1, m2, n1 and n2 is 2 to 40.)

Representative examples of A and B in the general formula (I) include an ethylene group, a propylene group, an isopropylene group, a butylene group, and an isobutylene group. It may be composed of only one type of alkylene group or a mixture of a plurality of types of alkylene groups. Most suitable are ethylene or isopropylene groups.
As the number of alkyleneoxy (A-O) chains and (B-O) chains, the total of m1, m2, n1, and n2 is preferably in the range of 2-40. Furthermore, the range of 4-14 is more preferable. When the total of m1, m2, n1, and n2 is 1 or less, the dispersibility when the photosensitive resin is dispersed in the developer is deteriorated. When the sum of m1, m2, n1, and n2 is 41 or more, the resolution is lowered.

  Further, as the (b) addition polymerizable monomer used in the present invention, 2,2-bis {(4-acryloxypolyethoxy) phenyl} propane or 2,2-bis {(4-methacryloxypoly) is preferable. Ethoxy) phenyl} propane. The polyethoxy group of the compound is a monoethoxy group, diethoxy group, triethoxy group, tetraethoxy group, pentaethoxy group, hexaethoxy group, heptaethoxy group, octaethoxy group, nonaethoxy group, decaethoxy group, undecaethoxy group, Examples thereof include compounds that are any group selected from the group consisting of a dodecaethoxy group, a tridecaethoxy group, a tetradecaethoxy group, and a pentadecaethoxy group. Examples of the alkylene group include a mixture of an ethylene group and a propylene group. 2,2-bis {(4-acryloxypolyalkyleneoxy) phenyl} propane or 2,2-bis {(4-methacryloxypolyalkyleneoxy) ) Phenyl} propane alkyleneoxy group is an octaethoxy group and dipropyloxy group block structure adduct or random structure adduct, tetraethoxy group and tetrapropyloxy group block structure adduct or random structure adduct Is mentioned. Among these, 2,2-bis {(4-methacryloxypentaethoxy) phenyl} propane is most preferable.

As the addition polymerizable monomer (b) used in the photosensitive resin composition of the present invention, a known compound having at least one terminal ethylenically unsaturated group can be used in addition to the above.
For example, 4-nonylphenylheptaethylene glycol dipropylene glycol acrylate, 2-hydroxy-3-phenoxypropyl acrylate, phenoxyhexaethylene glycol acrylate, a reaction product of a half ester compound of phthalic anhydride and 2-hydroxypropyl acrylate and propylene oxide (Nippon Shokubai Chemical Co., Ltd., trade name OE-A 200), 4-normal octylphenoxypentapropylene glycol acrylate, 1,6-hexanediol (meth) acrylate, 1,4-cyclohexanediol di (meth) acrylate, and polypropylene glycol Di (meth) acrylate, polyethylene glycol di (meth) acrylate, polyoxyethylene polyoxypropylene glycol di (meth) acrylate, etc. Polyoxyalkylene glycol di (meth) acrylate, 2-di (p-hydroxyphenyl) propane di (meth) acrylate, glycerol tri (meth) acrylate, trimethylolpropane triglycidyl ether tri (meth) acrylate, hexamethylene diisocyanate and nonapropylene Examples thereof include polyfunctional group (meth) acrylates containing urethane groups such as urethanates with glycol monomethacrylate, and polyfunctional (meth) acrylates of isocyanuric acid ester compounds. These may be used alone or in combination of two or more.
Among these, 2,2-bis {(4- (meth) acryloxypolyethoxy) cyclohexyl} propane and glycol tetraacrylate obtained by adding ethylene oxide to pentaerythritol are particularly preferable.

Examples of 2,2-bis {(4- (meth) acryloxypolyethoxy) cyclohexyl} propane include 2,2-bis {(4-acryloxypolyethoxy) cyclohexyl} propane or 2,2-bis {( 4-methacryloxypolyethoxy) cyclohexyl} propane has an ethoxy group of monoethoxy, diethoxy, triethoxy, tetraethoxy, pentaethoxy, hexaethoxy, heptaethoxy, octaethoxy, nonaethoxy, decaethoxy, undecaethoxy, dodecaethoxy, tridecaethoxy , Tetradecaethoxy, pentadecaethoxy, and examples of the alkylene group include a mixture of an ethylene group and a propylene group. 2,2-bis {(4-acryloxypolyalkyleneoxy) cyclohexyl} propane or 2,2- Bis {(4-methacrylo (Cypolyalkyleneoxy) cyclohexyl} The alkyleneoxy group of the propylene has an octaethoxy and dipropyloxy block structure adduct and a random structure adduct, and a tetraethoxy and tetrapropyloxy block structure adduct and a random structure adduct. Is mentioned. Of these, pentaethoxy dimethacrylate is most preferred.

  Examples of glycol tetraacrylates obtained by adding ethylene oxide to pentaerythritol include pentaerythritol tetra (meth) acrylate, pentaerythritol ethoxylated tetra (meth) acrylate, and pentaerythritol propoxylated tetra (meth) acrylate. . These may be used alone or in combination of two or more. Of these, pentaerythritol ethoxylated tetraacrylate is most preferred.

The amount of the (b) addition polymerizable monomer contained in the photosensitive resin composition of the present invention is in the range of 5 to 75% by mass, and more preferably in the range of 15 to 70% by mass. This amount is 5% by mass or more from the viewpoint of suppressing poor curing and development time delay, and is 75% by mass or less from the viewpoint of suppressing cold flow and delayed peeling of the cured resist.
(C) Photopolymerization initiator In the present invention, as (c) a photopolymerization initiator, those generally known can be used, but it is preferable to contain a triarylimidazolyl dimer.

Examples of the triarylimidazolyl dimer described above include 2- (o-chlorophenyl) -4,5-diphenylimidazolyl dimer, 2,2 ′, 5-tris- (o-chlorophenyl) -4- (3 , 4-dimethoxyphenyl) -4 ′, 5′-diphenylimidazolyl dimer, 2,4-bis- (o-chlorophenyl) -5- (3,4-dimethoxyphenyl) -diphenylimidazolyl dimer, 2, 4,5-tris- (o-chlorophenyl) -diphenylimidazolyl dimer, 2- (o-chlorophenyl) -bis-4,5- (3,4-dimethoxyphenyl) -imidazolyl dimer, 2,2 ′ -Bis- (2-fluorophenyl) -4,4 ', 5,5'-tetrakis- (3-methoxyphenyl) -imidazolyl dimer, 2,2'-bis- (2,3-difluoromethylphenol) Enyl) -4,4 ′, 5,5′-tetrakis- (3-methoxyphenyl) -imidazolyl dimer, 2,2′-bis- (2,4-difluorophenyl) -4,4 ′, 5 5′-tetrakis- (3-methoxyphenyl) -imidazolyl dimer, 2,2′-bis- (2,5-difluorophenyl) -4,4 ′, 5,5′-tetrakis- (3-methoxyphenyl) ) -Imidazolyl dimer, 2,2′-bis- (2,6-difluorophenyl) -4,4 ′, 5,5′-tetrakis- (3-methoxyphenyl) -imidazolyl dimer, 2,2 '-Bis- (2,3,4-trifluorophenyl) -4,4', 5,5'-tetrakis- (3-methoxyphenyl) -imidazolyl dimer, 2,2'-bis- (2, 3,5-trifluorophenyl) -4,4 ′, 5,5′-tetrakis- (3 Methoxyphenyl) -imidazolyl dimer, 2,2′-bis- (2,3,6-trifluorophenyl) -4,4 ′, 5,5′-tetrakis- (3-methoxyphenyl) -imidazolyl dimer 2,2′-bis- (2,4,5-trifluorophenyl) -4,4 ′, 5,5′-tetrakis- (3-methoxyphenyl) -imidazolyl dimer, 2,2′- Bis- (2,4,6-trifluorophenyl) -4,4 ′, 5,5′-tetrakis- (3-methoxyphenyl) -imidazolyl dimer, 2,2′-bis- (2,3, 4,5-tetrafluorophenyl) -4,4 ′, 5,5′-tetrakis- (3-methoxyphenyl) -imidazolyl dimer, 2,2′-bis- (2,3,4,6-tetra Fluorophenyl) -4,4 ′, 5,5′-tetrakis- (3-methoxypheny L) -imidazolyl dimer and 2,2′-bis- (2,3,4,5,6-pentafluorophenyl) -4,4 ′, 5,5′-tetrakis- (3-methoxyphenyl) -An imidazolyl dimer etc. are mentioned. In particular, 2- (o-chlorophenyl) -4,5-diphenylimidazolyl dimer is a photopolymerization initiator having a high effect on resolution and strength of a cured film, and is preferably used.
These may be used alone or in combination of two or more.

The amount of the triarylimidazolyl dimer contained in the photosensitive resin composition of the present invention is 0.00.
01-10 mass% is preferable, More preferably, it is 0.05-5 mass%, Most preferably, it is 0.1-4 mass%. This amount is required to be 0.01% by mass or more from the viewpoint of obtaining sufficient sensitivity, and is 10% by mass or less from the viewpoint of maintaining high resolution.
Moreover, it is also possible to use together the photoinitiator other than a triaryl imidazolyl dimer with the photosensitive resin composition of this invention. Examples of such a photopolymerization initiator include 2-ethylanthraquinone, octaethylanthraquinone, 1,2-benzanthraquinone, 2,3-benzanthraquinone, 2-phenylanthraquinone, 2,3-diphenylanthraquinone, 1-chloro. Quinones such as anthraquinone, 1,4-naphthoquinone, 9,10-phenanthraquinone, 2-methyl-1,4-naphthoquinone, 2,3-dimethylanthraquinone, 3-chloro-2-methylanthraquinone, benzophenone, Michler's ketone [4,4′-bis (dimethylamino) benzophenone], aromatic ketones such as 4,4′-bis (diethylamino) benzophenone, benzoin, benzoin ethyl ether, benzoin phenyl ether, methyl benzoin, ethyl benzoin, etc. Benzoin ethers, benzyl dimethyl ketal, benzyl diethyl ketal, N-phenyl glycine, N-methyl-N-phenyl glycine, N-ethyl-N-phenyl glycine and other N-phenyl glycines, thioxanthones and alkylaminobenzoic acid Combinations such as ethylthioxanthone and ethyl dimethylaminobenzoate, 2-chlorothioxanthone and ethyl dimethylaminobenzoate, isopropylthioxanthone and ethyl dimethylaminobenzoate, acridines such as 9-phenylacridine, 1-phenyl-1, There are oxime esters such as 2-propanedione-2- ◯ -benzoin oxime and 1-phenyl-1,2-propanedione-2- (O-ethoxycarbonyl) oxime.

In addition to the triarylimidazolyl dimer, preferred examples of the photopolymerization initiator added to the photosensitive resin composition of the present invention include thioxanthones such as diethylthioxanthone and chlorothioxanthone, and dialkylaminobenzoic acids such as ethyl dimethylaminobenzoate. Esters, benzophenone, 4,4′-bis (dimethylamino) benzophenone [Michler's ketone], 4,4′-bis (diethylamino) benzophenone, 9-phenylacridine, N-phenylglycines, 1-phenyl-3- (4 -Tert-butyl-styryl) -5- (p-tert-butyl-phenyl) -pyrazoline, 1- (4- (benzoxazol-2-yl) phenyl) -3- (4-tert-butylstyryl) -5 -(4-tert-butylphenyl) -pyrazolin represented by pyrazoline Zolins and combinations thereof may be mentioned. Among these, Michler's ketone or 4,4′-bis (diethylamino) benzophenone, 1-phenyl-3- (4-tert-butyl-styryl) -5- (p-tert-butyl-phenyl) -pyrazoline, 1- (4 -(Benzoxazol-2-yl) phenyl) -3- (4-tert-butylstyryl) -5- (4-tert-butylphenyl) -pyrazoline is particularly preferred.
The amount of the photopolymerization initiator (c) contained in the photosensitive resin composition of the present invention is preferably 0.01 to 30% by mass, and more preferably 0.1 to 15% by mass. This amount is 0.01% by mass or more from the viewpoint of obtaining sufficient sensitivity, and is 30% by mass or less from the viewpoint of high resolution.

(D) Other components In the photosensitive resin composition of the present invention, in addition to the components described above, coloring substances such as dyes and pigments can be employed. Examples of such coloring substances include phthalocyanine green, crystal violet, methyl orange, Nile blue 2B, Victoria blue, malachite green, basic blue 20, diamond green, and the like.
Moreover, you may add a color former in the photosensitive resin composition of this invention so that a visible image can be given by exposure. Such coloring dyes include leuco dyes or combinations of fluoran dyes and halogen compounds. As the dye used here, in addition to the above-mentioned dyes, halogen compounds such as amyl bromide, isoamyl bromide, isobutylene bromide, ethylene bromide, diphenylmethyl bromide, benzal bromide, methylene bromide, tribromomethylphenyl Sulfone, carbon tetrabromide, tris (2,3-dibromopropyl) phosphate, trichloroacetamide, amyl iodide, isobutyl iodide, 1,1,1-trichloro-2,2-bis (p-chlorophenyl) ethane, hexa Examples include chloroethane and triazine compounds.
The amount of the coloring substance and the color former is preferably 0.01 to 10% by mass in the photosensitive resin composition. It is preferably 0.01% by mass or more from the viewpoint of recognizing sufficient colorability (coloring property), 10% by mass or less from the viewpoint of maintaining the contrast between the exposed part and the unexposed part and maintaining storage stability.

Furthermore, in order to improve the thermal stability and storage stability of the photosensitive resin composition of the present invention, it is preferable that the photosensitive resin composition contains a radical polymerization inhibitor and benzotriazoles.
Examples of such radical polymerization inhibitors include p-methoxyphenol, hydroquinone, pyrogallol, naphthylamine, tert-butylcatechol, cuprous chloride, 2,6-di-tert-butyl-p-cresol, 2,2 Examples include '-methylenebis (4-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), nitrosophenylhydroxyamine aluminum salt, diphenylnitrosamine and the like.

  Examples of benzotriazoles include 1,2,3-benzotriazole, 1-chloro-1,2,3-benzotriazole, and bis (N-2-ethylhexyl) aminomethylene-1,2,3-benzo. Examples include triazole, bis (N-2-ethylhexyl) aminomethylene-1,2,3-tolyltriazole, bis (N-2-hydroxyethyl) aminomethylene-1,2,3-benzotriazole. Examples of carboxybenzotriazoles include 4-carboxy-1,2,3-benzotriazole, 5-carboxy-1,2,3-benzotriazole, and N- (N, N-di-2-ethylhexyl). Examples include aminomethylenecarboxybenzotriazole, N- (N, N-di-2-hydroxyethyl) aminomethylenecarboxybenzotriazole, N- (N, N-di-2-ethylhexyl) aminoethylenecarboxybenzotriazole and the like.

The total addition amount of the radical polymerization inhibitor and the benzotriazoles is preferably 0.01 to 3% by mass, more preferably 0.05 to 1% by mass. This amount is preferably 0.01% by mass or more from the viewpoint of imparting storage stability to the photosensitive resin composition, and more preferably 3% by mass or less from the viewpoint of maintaining photosensitivity.
These radical polymerization inhibitors and benzotriazole compounds may be used alone or in combination of two or more.

  You may make the photosensitive resin composition of this invention contain additives, such as a plasticizer, as needed. Examples of such additives include polyethylene glycol, polypropylene glycol, polyoxypropylene polyoxyethylene ether, polyoxyethylene monomethyl ether, polyoxypropylene monomethyl ether, polyoxyethylene polyoxypropylene monomethyl ether, polyoxyethylene monoethyl Ethers, polyoxypropylene monoethyl ether, glycol esters such as polyoxyethylene polyoxypropylene monoethyl ether, phthalic acid esters such as diethyl phthalate, o-toluenesulfonic acid amide, p-toluenesulfonic acid amide, citric acid Tributyl, triethyl citrate, triethyl acetylcitrate, tri-n-propyl acetylcitrate, tri-n-acetylcitrate Chill, and the like.

The amount of the additive such as a plasticizer is preferably 5 to 50% by mass, more preferably 5 to 30% by mass in the photosensitive resin composition. 5 mass% or more is preferable from a viewpoint of suppressing the delay of image development time or providing a softness | flexibility to a cured film, and 50 mass% or less is preferable from a viewpoint of suppressing insufficient hardening and cold flow.
The photosensitive resin composition of the present invention may contain a solvent in order to obtain a preparation solution in which the above (a) to (c) and (d) are appropriately dissolved. Examples of the solvent used include ketones typified by methyl ethyl ketone (MEK), and alcohols such as methanol, ethanol, and isopropyl alcohol. It is preferable to prepare the solvent so that the viscosity of the preparation liquid of the photosensitive resin composition is 500 to 4000 mPa · sec at 25 ° C.

<Photosensitive resin laminate>
The photosensitive resin laminate of the present invention comprises a photosensitive resin layer and a support that supports the layer. If necessary, the photosensitive resin laminate may have a protective layer on the surface opposite to the support of the photosensitive resin layer. good.
The support used here is preferably a transparent one that transmits light emitted from the exposure light source. Examples of such a support include polyethylene terephthalate film, polyvinyl alcohol film, polyvinyl chloride film, vinyl chloride copolymer film, polyvinylidene chloride film, vinylidene chloride copolymer film, polymethyl methacrylate copolymer film, polystyrene film. , Polyacrylonitrile film, styrene copolymer film, polyamide film, cellulose derivative film and the like. These films can be stretched if necessary. The haze is preferably 5 or less. The thinner the film, the more advantageous in terms of image forming property and economic efficiency, but a film having a thickness of 10 to 30 μm is preferably used because of the necessity of maintaining the strength.
Further, an important characteristic of the protective layer used in the photosensitive resin laminate is that the protective layer is sufficiently smaller than the support and can be easily peeled with respect to the adhesion with the photosensitive resin layer. For example, a polyethylene film or a polypropylene film can be preferably used as the protective layer. Also, a film having excellent peelability disclosed in JP-A-59-202457 can be used.
The thickness of the protective layer is preferably 10 to 100 μm, and more preferably 10 to 50 μm.

Although the thickness of the photosensitive resin layer in the photosensitive resin laminate of the present invention varies depending on the application, it is preferably 5 to 100 μm, more preferably 7 to 60 μm. The thinner the resolution, the better the resolution. The film strength is improved.
A conventionally known method can be adopted as a method for preparing the photosensitive resin laminate of the present invention by sequentially laminating a support, a photosensitive resin layer, and if necessary, a protective layer.
For example, the photosensitive resin composition used for the photosensitive resin layer is mixed with a solvent that dissolves them to form a uniform solution, and is first coated on a support using a bar coater or roll coater, dried, and then supported. A photosensitive resin layer made of a photosensitive resin composition is laminated on the body.
Next, if necessary, a photosensitive resin laminate can be prepared by laminating a protective layer on the photosensitive resin layer.

<Resist pattern formation method>
A resist pattern using the photosensitive resin laminate of the present invention can be formed by a process including a lamination process, an exposure process, and a development process. An example of a specific method is shown.
First, a lamination process is performed using a laminator. In the case where the photosensitive resin laminate has a protective layer, the protective layer is peeled off, and then the photosensitive resin layer is heat-pressed and laminated on the substrate surface with a laminator. In this case, the photosensitive resin layer may be laminated only on one side of the substrate surface or on both sides. The heating temperature at this time is generally 40 to 160 ° C. Moreover, adhesion and chemical resistance are improved by performing the thermocompression bonding twice or more. At this time, for the crimping, a two-stage laminator having two rolls may be used, or it may be repeatedly crimped through the roll several times.

Next, an exposure process is performed using an exposure machine. If necessary, the support may be peeled off. When exposure is performed with active light through a photomask, the amount of exposure is determined by the light source illuminance and the exposure time. You may measure using a photometer.
In the exposure step, a direct drawing exposure method may be used. In direct drawing exposure, exposure is performed by directly drawing on a substrate without using a photomask. As the light source, a semiconductor laser having a wavelength of 350 to 410 nm, an ultrahigh pressure mercury lamp, or the like is used. The drawing pattern is controlled by a computer, and the exposure amount in this case is determined by the light source illuminance and the moving speed of the substrate.

Next, a developing process is performed using a developing device. After the exposure, if there is a support on the photosensitive resin layer, it is removed if necessary, and then the unexposed portion is developed and removed using a developer of an alkaline aqueous solution to obtain a resist image. An aqueous solution of Na ₂ CO ₃ , K ₂ CO ₃ or the like is used as the alkaline aqueous solution. These are selected in accordance with the characteristics of the photosensitive resin layer, but a Na ₂ CO ₃ aqueous solution having a concentration of 0.2 to 2% by mass and 20 to 40 ° C. is generally used. A surface active agent, an antifoaming agent, a small amount of an organic solvent for promoting development, and the like may be mixed in the alkaline aqueous solution.
Although a resist pattern is obtained by the above-mentioned process, a heating process at 100 to 300 ° C. can be further performed depending on the case. By carrying out this heating step, chemical resistance can be further improved. For heating, a heating furnace of a hot air, infrared ray, far infrared ray or the like is used.

<Method for manufacturing printed wiring board>
The method for producing a printed wiring board according to the present invention is performed through the following steps following the above-described resist pattern forming method using a copper-clad laminate or a flexible substrate as a substrate.
First, a conductor pattern is formed on the copper surface exposed by development using a known method such as an etching method or a plating method.
Thereafter, the resist pattern is peeled from the substrate with an aqueous solution having alkalinity stronger than that of the developer to obtain a desired printed wiring board. The alkaline aqueous solution for peeling (hereinafter also referred to as “peeling solution”) is not particularly limited, but an aqueous solution of NaOH or KOH at a concentration of 2 to 5% by mass, 40 to 70 ° C. is generally used. It is possible to add a small amount of a water-soluble solvent to the stripping solution.

<Lead frame manufacturing method>
The lead frame manufacturing method of the present invention is performed through the following steps following the above-described resist pattern forming method using a metal plate of copper, copper alloy, iron-based alloy or the like as a substrate.
First, a conductive pattern is formed by etching the substrate exposed by development.
Thereafter, the resist pattern is peeled off by a method similar to the method for manufacturing a printed wiring board described above to obtain a desired lead frame.

<Semiconductor package manufacturing method>
The method for producing a semiconductor package of the present invention is performed by performing the following steps following the above-described resist pattern forming method using a wafer on which a circuit as an LSI has been formed as a substrate.
A conductor pattern is formed by performing columnar plating such as copper or solder on the opening exposed by development.
Thereafter, the resist pattern is peeled by the same method as the above-described printed wiring board manufacturing method, and the thin metal layer other than the columnar plating is removed by etching to obtain a desired semiconductor package.

<Manufacturing method of flat display>
When processing the substrate by the sandblasting method using the photosensitive resin laminate of the present invention as a dry film resist, the photosensitive resin laminate is laminated on the substrate in the same manner as described above, Exposure and development are performed. Further, a blasting material is sprayed from the formed resist pattern to be cut to a desired depth, and a resin part remaining on the base material is removed from the base material with an alkaline stripping solution, etc. A fine pattern can be processed. The known blasting material used in the sandblasting process includes fine particles of about 2 to 100 μm such as SiC, SiO ₂ , Al ₂ O ₃ , CaCO ₃ , ZrO, glass, stainless steel and the like.

Hereinafter, examples of embodiments of the present invention will be described in more detail by way of examples.
First, a method for producing samples for evaluation of Examples and Comparative Examples will be described, and then an evaluation method and evaluation results for the obtained samples will be shown.
1. Production of Evaluation Sample The photosensitive resin laminates in Examples and Comparative Examples were produced as follows.

<Preparation of photosensitive resin laminate>
The photosensitive resin composition having the composition shown in Table 1 is thoroughly stirred and mixed, and uniformly coated on the surface of a 16 μm-thick polyethylene terephthalate film as a support using a bar coater, and dried in a 95 ° C. dryer for 3 minutes. Thus, a photosensitive resin layer was formed. The thickness of the photosensitive resin layer was 40 μm. In Table 1, the mass part of P-1 is a value including methyl ethyl ketone.
Next, a 23 μm thick polyethylene film was laminated as a protective layer on the surface of the photosensitive resin layer on which the polyethylene terephthalate film was not laminated to obtain a photosensitive resin laminate.
Table 2 shows the names of the material components in the photosensitive resin composition represented by abbreviations in Table 1.
Comparative Examples 1 to 3 are compositions whose transmittance at 405 nm is not 15 to 40%.

<Board surface preparation>
The substrate for evaluation was a 1.6 mm thick copper clad laminate on which 35 μm rolled copper foil was laminated, and the surface was wet buffol polished (manufactured by 3M Co., Ltd., Scotch Bright (registered trademark) HD # 600, 2 passes). did.
<Laminate>
While peeling the polyethylene film of the photosensitive resin laminate, it was laminated at a roll temperature of 105 ° C. with a hot roll laminator (Asahi Kasei Electronics Co., Ltd., AL-70) on a copper clad laminate that had been leveled and preheated to 60 ° C. . The air pressure was 0.35 MPa, and the laminating speed was 1.5 m / min.

<Exposure>
(Direct drawing exposure) Exposure in which the number of step tablet steps is 8 by the following sensitivity evaluation using a direct drawing type exposure apparatus (PIIC Corporation, DI exposure machine “DI-2080”, light source: GaN blue-violet diode, main wavelength 405 nm). Exposed in quantity.
<Development>
After the polyethylene terephthalate film was peeled off, a 1 mass% Na ₂ CO ₃ aqueous solution at 30 ° C. was sprayed for a predetermined time to dissolve and remove the unexposed portion of the photosensitive resin layer. At this time, the minimum time required for completely dissolving the photosensitive resin layer in the unexposed portion was defined as the minimum development time. <Etching>
An evaluation substrate on which a resist pattern was formed by development was sprayed with a cupric chloride etching solution at 50 ° C. having a cupric chloride concentration of 250 g / l and a hydrochloric acid concentration of 3 mol / l for a predetermined time, and then on the copper clad laminate. The portion of the copper foil not covered with the resist pattern was dissolved and removed.

2. Evaluation Method (1) Transmittance Measurement The polyethylene film was peeled off from the photosensitive resin laminate obtained in the above <Preparation of photosensitive resin laminate> step, and UV-vis spectrometer (manufactured by Shimadzu Corporation, UV-240). ) Was used to measure the transmittance of light having a wavelength of 405 nm. At this time, the same polyethylene terephthalate film as that used for the photosensitive resin laminate was put on the reference side of the spectrometer to cancel the transmittance derived from the polyethylene terephthalate film.

(2) Sensitivity measurement The substrate for sensitivity and resolution evaluation 15 minutes after the above <laminate> step was exposed using a 21-step tablet manufactured by Stofer whose brightness has changed from transparent to black in 21 steps. After the exposure, development was performed with a development time twice as long as the minimum development time, and the exposure amount at which the number of step tablet stages where the resist film remained completely was 8 was determined.
A: The exposure amount is 10 mJ / cm ² or less.
○: The exposure amount exceeds 10 mJ / cm ² and is 15 mJ / cm ² or less.
△: exposure amount is more than ^{15mJ / cm 2, 30mJ / cm} 2 or less.
X: The exposure amount exceeds 30 mJ / cm ² .

(3) Resolution Evaluation The substrate for sensitivity and resolution evaluation 15 minutes after the <laminate> step was exposed through a line pattern mask in which the width of the exposed area and the unexposed area was 1: 1. Development was performed with a development time twice as long as the minimum development time, and the minimum mask line width in which a cured resist line was normally formed was defined as a resolution value.
A: The resolution value is 30 μm or less.
○: The resolution value exceeds 30 μm and is 45 μm or less.
Δ: The value of resolution exceeds 45 μm.

(4) Adhesion Evaluation The substrate for sensitivity and resolution evaluation 15 minutes after the <laminate> step was exposed through a line pattern mask in which the width of the exposed area and the unexposed area was 1: 1. Development was performed with a development time twice as long as the minimum development time, and the minimum mask line width in which a cured resist line was normally formed was defined as an adhesion value.
A: Adhesion value is 30 μm or less.
○: Adhesion value exceeds 30 μm and 45 μm or less.
(Triangle | delta): The value of adhesiveness exceeds 45 micrometers.

3. Evaluation Results The evaluation results of the examples and comparative examples are shown in Table 1.

The present invention relates to the manufacture of printed wiring boards, the manufacture of lead frames for mounting IC chips, the manufacture of precision metal foils such as the manufacture of metal masks, the manufacture of packages such as BGA and CSP, COF and TA
It can be used for the production of a tape substrate such as B, the production of semiconductor bumps, the production of partition walls for flat panel displays such as ITO electrodes, address electrodes, and electromagnetic wave shields, and the method of processing a substrate by sandblasting. Examples of the processing by the sandblasting method include organic EL glass cap processing, drilling processing of a silicon wafer, and ceramic pinning processing. Furthermore, the processing by the sand blasting process of the present invention can be used for manufacturing an electrode of a metal material layer selected from the group consisting of a ferroelectric film and a noble metal, a noble metal alloy, a refractory metal, and a refractory metal compound.

Claims (9)

  (A) Thermoplastic copolymer containing an α, β-unsaturated carboxyl group-containing monomer as a copolymerization component and having an acid equivalent of 100 to 600 and a weight average molecular weight of 5000 to 500,000: 20 to 90% by mass ( b) Photosensitive resin composition comprising addition polymerizable monomer having at least one terminal ethylenically unsaturated group: 5 to 75% by mass, and (c) photopolymerization initiator: 0.01 to 30% by mass. A photosensitive resin layer obtained by applying the photosensitive resin composition on a support and drying the photosensitive resin layer at 405 nm has a transmittance of 15 to 40% in terms of a film thickness of 40 μm. Resin composition. (B) The photosensitive resin composition according to claim 1, wherein the addition polymerizable monomer contains a compound of the following general formula (I).

(In the formula, R ₁ and R ₂ are H or CH ₃ , which may be the same or different. A and B are alkylene groups having 2 to 4 carbon atoms; Each may be the same or different, m1, m2, n1 and n2 are 0 or a positive integer, and the sum of m1, m2, n1 and n2 is 2 to 40.)   The photosensitive resin laminated body formed by laminating | stacking the photosensitive resin composition of Claim 1 or Claim 2 on a support body.   A method of forming a resist pattern, comprising: sequentially laminating a photosensitive resin layer using the photosensitive resin laminate according to claim 3, an exposure step, and a developing step.   5. The resist pattern forming method according to claim 4, wherein in the exposure step, direct drawing exposure is performed.   A method for producing a printed wiring board by etching or plating a substrate on which a resist pattern is formed by the method according to claim 4.   A method of manufacturing a lead frame by etching a substrate on which a resist pattern is formed by the method according to claim 4.   A method for manufacturing a semiconductor package, comprising a step of etching or plating a substrate on which a resist pattern is formed by the method according to claim 4.   A method for processing a substrate on which a resist pattern is formed by the method according to claim 4 or 5 by a sandblasting process.