JP4986591B2 - Photosensitive resin composition and use thereof - Google Patents

Description

  The present invention relates to a photosensitive resin composition and use thereof, and in particular, a photosensitive resin laminate suitable for manufacturing a conductive pattern such as a printed wiring board and a lead frame including a rigid board and a flexible board, and a resist using the same. The present invention relates to a pattern forming method, a conductor pattern manufacturing method, a printed wiring board manufacturing method, a semiconductor package manufacturing method, a lead frame manufacturing method, and a concavo-convex substrate manufacturing method.

For electronic devices such as personal computers and mobile phones, printed wiring boards and the like are used for mounting components and semiconductors. As a resist for manufacturing a printed wiring board or the like, a so-called dry film resist (hereinafter abbreviated as DFR) in which a support, a photosensitive resin layer, and a protective layer as necessary are further laminated has been used. The DFR is generally prepared by laminating a photosensitive resin layer on a support, and further laminating a protective layer on the photosensitive resin layer as necessary. As the photosensitive resin layer used here, an alkali developing type using a weak alkaline aqueous solution as a developing solution is generally used.
To create a printed wiring board using DFR, first peel off the protective layer, then laminate the DFR on a permanent circuit creation board such as a copper-clad laminate or flexible board using a laminator, etc. The support is peeled off and exposed through a wiring pattern mask film or the like. Next, if there is a support, it is peeled off, and the photosensitive resin layer in the unexposed part is dissolved or dispersed and removed by a developer to form a resist pattern on the substrate.

After forming the resist pattern, the process for forming a circuit is roughly divided into two methods. The first method is a method in which after removing a copper surface such as a copper clad laminate not covered with a resist pattern by etching, the resist pattern portion is removed with an alkaline aqueous solution stronger than the developer. In this case, for simplicity of the process, a method (tenting method) in which a through hole (through hole) is covered with a cured film and then etched is frequently used. The second method is a method in which the copper surface of the above is subjected to plating treatment of copper, solder, nickel, tin, etc., and then the resist pattern portion is similarly removed, and the copper surface such as a copper-clad laminate appearing is etched ( Plating method). In any case, cupric chloride, ferric chloride, a copper ammonia complex solution or the like is used for etching.
In recent printed wiring boards, high resolution of resists is required for higher integration of wiring.

Furthermore, multilayered printed wiring boards are being developed by the build-up method. As the number of layers increases, irregularities appear on the substrate due to the influence of inner layer wiring and via holes. In such a substrate, when the DFR is laminated, the photosensitive resin composition layer cannot sufficiently fill the unevenness on the substrate, and a void may be generated. At the time of etching, the etching solution penetrates into the gap, and defects such as disconnection and chipping occur. The ability to fill this unevenness is called followability.
In order to prevent the followability from deteriorating, there is a method of increasing the fluidity of the photosensitive resin composition layer to make it softer. However, since DFR has a three-layer structure and is stored in the form of a roll tightly wound around a core such as plastic, if the photosensitive resin composition layer is soft, the photosensitive resin composition from the roll end face during storage A so-called edge fuse phenomenon occurs in which the material layer protrudes. The protruding photosensitive resin composition has a problem that it adheres to a substrate, a mask or the like at the time of lamination or the like and induces a defect such as a short circuit. For this reason, it is preferable from the viewpoint of handling that the edge fuse property is good, that is, the photopolymerizable resin layer is difficult to protrude. For this reason, the DFR is desired to have both conflicting performances of edge fuse and followability.

The step of dissolving or dispersing and removing the photosensitive resin layer in the unexposed portion with a developer after exposure is called a development step. Not all DFR components dissolve in the developer, and since the developer is recycled, the insoluble components with poor developer dispersibility increase each time the development process is repeated, and aggregates (scum) are generated. appear. Aggregates re-adhere on the substrate, causing a short circuit failure in the tenting and etching methods, and may clog the developing tank piping. Therefore, there is a need for a DFR that reduces aggregates during development.
Accordingly, there has been a demand for a photosensitive resin composition having high resolution, excellent developer dispersion stability in the development process, and does not generate aggregates, and has good edge fuse properties and followability.
For the purpose of reducing aggregates during development, Patent Document 1 discloses an attempt to use an alkylphenol type monofunctional monomer having good developer dispersion as a photopolymerizable unsaturated compound, and Patent Document 2 discloses a phenoxy type monofunctional compound. There are disclosures of attempts to use monomers, but none of them satisfied the current situation.

Patent Documents 3 and 4 disclose a photosensitive resin composition using a binder resin containing benzyl methacrylate as a copolymer component. However, 2-ethylhexyl (meth) acrylate is used as a copolymer component. There was no disclosure about what was contained, and there was no disclosure about DFR excellent in followability.
Patent Documents 5 and 6 disclose a photosensitive resin composition using a binder resin containing benzyl methacrylate and 2-ethylhexyl acrylate as copolymer components. However, the content of benzyl methacrylate in the copolymer is disclosed. Was limited to 10% or less, and as shown in Comparative Examples described later, did not exhibit sufficient effects on cohesion and followability.
Patent Document 7, Patent Document 8, and Patent Document 9 disclose a photosensitive resin composition using a resin for a binder containing benzyl methacrylate and 2-ethylhexyl acrylate as copolymer components. The content of benzyl methacrylate was limited to 20% or less, and as shown in a comparative example described later, sufficient effects on cohesiveness and followability were not exhibited.

JP 2001-174986 A JP 2001-305730 A JP 2005-121790 A JP-A-2005-301101 JP 2005-258092 A JP 2005-148236 A JP-A-63-147159 JP 2005-10205 A JP 10-78654 A

  The present invention contains a photosensitive resin composition having good post-development resolution, excellent developer dispersion stability, no agglomerates, good edge fuse and followability, and the composition. It aims at providing the photosensitive resin laminated body which has a photosensitive resin layer, and the manufacturing method of the formation method of a resist pattern using this laminated body, and a conductor pattern.

As a result of studying to solve the above-mentioned problems, by using a specific photosensitive resin composition, the resolution after development is good, the developer dispersion stability is excellent, no aggregates are generated, and good edge fuse properties are obtained. It has been found that it is possible to form a good conductor pattern with followability, and the present invention has been achieved.
That is, the present invention is as follows.
1. With respect to the total sum of the photosensitive resin composition, (a) it is 100 to 550 with a carboxyl group content of acid equivalent, 30 to 80% by weight of benzyl (meth) acrylate as a copolymer component as a copolymer component, 2 -Resin for binders containing 3 to 60% by mass of ethylhexyl (meth) acrylate as a copolymer component and having a weight average molecular weight of 5,000 to 500,000: 20 to 90% by mass, (b) Photopolymerizable monomer: A photosensitive resin composition comprising 3 to 70% by mass and (c) a photopolymerization initiator: 0.1 to 20% by mass.

（式中、Ｘ、Ｙ、及びＺはそれぞれ独立に水素、炭素数１から５のアルキル基及びアルコキシ基、並びにハロゲン基のいずれかを表し、ｐ、ｑ、及びｒはそれぞれ独立に１〜５の整数である。） 2 . 2. The photosensitive resin composition as described in 1 above, which contains a 2,4,5-triarylimidazole dimer represented by the following general formula (I) as the photopolymerization initiator (c): .

(In the formula, X, Y, and Z each independently represent hydrogen, an alkyl group having 1 to 5 carbon atoms, an alkoxy group, or a halogen group, and p, q, and r are each independently 1 to 5) Is an integer.)

（Ｒ₁及びＲ₂は、それぞれ独立に、水素原子又はメチル基である。Ａ及びＢは炭素数２〜６のアルキレン基を示し、これらは同一であっても相違していてもよく、異なっている場合、−（Ａ−Ｏ）−及び−（Ｂ−Ｏ）−の繰り返し単位は、ブロック構造でもランダム構造でもよい。ｍ１、ｍ２、ｍ３及びｍ４は、０又は正の整数であり、これらの合計は２〜４０である。） 3 . 3. The photosensitive resin composition according to 1 or 2 above, which contains a compound represented by the following general formula (II) as the photopolymerizable monomer (b).

(R ₁ and R ₂ are each independently a hydrogen atom or a methyl group. A and B each represent an alkylene group having 2 to 6 carbon atoms, and these may be the same or different. The repeating unit of-(A-O)-and-(B-O)-may be a block structure or a random structure, and m1, m2, m3 and m4 are 0 or a positive integer, Is 2 to 40.)

4 . The photosensitive resin laminated body obtained by laminating | stacking on the support body the photosensitive resin composition as described in any one of said 1-3 as a photosensitive resin composition layer.
5 . 5. A method for forming a resist pattern, comprising: laminating the photosensitive resin laminate according to 4 above on a substrate, exposing to ultraviolet rays, and then removing an unexposed portion by development.
6 . 6. The resist pattern forming method according to 5 above, wherein the exposure step is performed without using a photomask.
7 . A method for producing a conductor pattern, comprising using a metal plate or a metal-coated insulating plate as a substrate and etching or plating a substrate on which a resist pattern is formed by the method described in 5 or 6 above.
8 . A method for producing a printed wiring board, comprising using a metal-coated insulating plate as a substrate, etching or plating a substrate on which a resist pattern is formed by the method described in 5 or 6 above, and peeling the resist pattern.

9 . A method for producing a lead frame, comprising: using a metal plate as a substrate; etching a substrate on which a resist pattern is formed by the method described in 5 or 6 above; and peeling the resist pattern.
10 . A method for producing a semiconductor package, comprising: using a wafer on which an LSI circuit has been formed as a substrate, plating a substrate on which a resist pattern is formed by the method described in 5 or 6 above, and peeling the resist pattern.
11 . Using a glass or glass coated with a rib paste as a substrate, a substrate on which a resist pattern is formed by the method described in 5 or 6 above is processed by a sandblasting method, and has a concavo-convex pattern characterized by peeling the resist pattern A method for producing a substrate.

  According to the present invention, the post-development resolution is good and the developer is excellent in dispersion stability in the development process. A photosensitive resin composition suitable for forming a conductor pattern and a photosensitive resin laminate having a photosensitive resin layer made of the composition can be provided.

Hereinafter, the present invention will be specifically described.
The resin for binder (a) used in the present invention has a carboxyl group content of 100 to 550 in terms of acid equivalent, 20 to 80% by mass of benzyl (meth) acrylate as a copolymer component, 2- It contains 3 to 60% by mass of ethylhexyl (meth) acrylate as a copolymer component and has a weight average molecular weight of 5,000 to 500,000.
(A) As for content of the carboxyl group of the resin for binders, 100-550 are preferable by an acid equivalent, More preferably, it is 300-450. An acid equivalent means the mass of the linear polymer which has a 1 equivalent carboxyl group in it. The carboxyl group in the binder resin is necessary to give the photosensitive resin layer developability and releasability with respect to an aqueous alkali solution. The acid equivalent is preferably 100 or more from the viewpoint of development resistance, resolution, and adhesion, and is preferably 550 or less from the viewpoint of developability and peelability. The acid equivalent is measured by a potentiometric titration method using a Hiranuma automatic titrator (COM-555) manufactured by Hiranuma Sangyo Co., Ltd., and using a 0.1 mol / L sodium hydroxide aqueous solution.

(A) It is preferable that the weight average molecular weight of resin for binders is 5000-500000. The weight average molecular weight of the binder resin is preferably 500000 or less from the viewpoint of resolution, and 5000 or more is preferable from the viewpoint of edge fuse. In order to better exhibit the effects of the present invention, the weight average molecular weight of the binder resin is more preferably 5,000 to 200,000, still more preferably 5,000 to 100,000. The binder resin has a degree of dispersion (sometimes referred to as molecular weight distribution) of about 1 to 6, preferably 1 to 4. The degree of dispersion is represented by the ratio between the weight average molecular weight and the number average molecular weight of the following formula.
(Dispersity) = (weight average molecular weight) / (number average molecular weight)

The weight average molecular weight was measured by Gel Permeation Chromatography (GPC) manufactured by JASCO Corporation (pump: GullIver, PU-1580 type, column: Shodex (registered trademark) manufactured by Showa Denko KK (KF-807, KF-806M). , KF-806M, KF-802.5) in series, moving bed solvent: tetrahydrofuran, polystyrene standard sample (use of calibration curve by Shodex STANDARD SM-105 Polystyrene manufactured by Showa Denko K.K.) ).
(A) Resin for binders has benzyl (meth) acrylate and 2-ethylhexyl (meth) acrylate as essential components.
(A) 20-80 mass% is preferable as a content rate as a copolymer component of the benzyl (meth) acrylate in binder resin. 80 mass% or less is preferable from a viewpoint of developability, and 20 mass% or more is preferable from the viewpoint of aggregation and followability. More preferably, it is 30-80 mass%, More preferably, it is 40-75 mass%, Most preferably, it is 55-85 mass%.

(A) As for the content rate as a copolymer component of 2-ethylhexyl (meth) acrylate in binder resin, 3-60 mass% is preferable. 60 mass% or less is preferable from a viewpoint of an edge fuse, and 3 mass% or more is preferable from a cohesive viewpoint. More preferably, it is 5-55 mass%, More preferably, it is 5-50 mass%, Most preferably, it is 5-40 mass%. From the viewpoint of followability, the use of 2-ethylhexyl acrylate is particularly preferable.
(A) The binder resin is obtained by copolymerizing at least one monomer from the following first monomers in addition to benzyl (meth) acrylate and 2-ethylhexyl (meth) acrylate. . The content of the first monomer is determined by the acid equivalent. Further, the following second monomer may be copolymerized as necessary.

The first monomer is a carboxylic acid or acid anhydride having one polymerizable unsaturated group in the molecule. Examples include (meth) acrylic acid, fumaric acid, cinnamic acid, crotonic acid, itaconic acid, maleic anhydride, maleic acid half ester, and the like.
The second monomer is a non-acidic compound having one polymerizable unsaturated group in the molecule. The compound is selected so as to maintain various properties such as developability of the photosensitive resin layer, resistance in etching and plating processes, and flexibility of the cured film. Examples of the compound include methyl (meth) acrylate, ethyl (meth) acrylate, alkyl (meth) acrylate such as butyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, Aryl (meth) acrylates such as (meth) acrylonitrile, furfuryl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, phenoxyethyl (meth) acrylate, phenyl (meth) acrylate, cresyl (meth) acrylate, naphthyl (meth) acrylate An aromatic ring of a benzyl (meth) acrylate such as a vinyl compound having a phenyl group (for example, styrene), methoxybenzyl (meth) acrylate or chlorobenzyl (meth) acrylate. · The group, a halogen, an alkyl group can be used compounds obtained by substituting.

(A) The binder resin is a mixture of benzyl (meth) acrylate and 2-ethylhexyl (meth) acrylate, the first monomer, and, if necessary, the second monomer. It is preferable to carry out the synthesis by adding an appropriate amount of a radical polymerization initiator such as benzoyl peroxide or azoisobutyronitrile to a solution diluted with a solvent such as methyl ethyl ketone or isopropanol, and stirring with heating. In some cases, the synthesis is performed while a part of the mixture is dropped into the reaction solution. After completion of the reaction, a solvent may be further added to adjust to a desired concentration. As synthesis means, bulk polymerization, suspension polymerization, or emulsion polymerization may be used in addition to solution polymerization.

  (A) The ratio with respect to the sum total of the photosensitive resin composition of resin for binders is the range of 20-90 mass%, Preferably it is 30-70 mass%. The resist pattern formed by exposure and development is preferably 20% by mass or more and 90% by mass or less from the viewpoint that the resist pattern has sufficient resistance as a resist, for example, tenting, etching, and various plating processes. Moreover, in the photosensitive resin composition of this invention, you may contain resin for binders other than the resin for binders which contains the said benzyl (meth) acrylate and 2-ethylhexyl (meth) acrylate as a copolymerization component.

（Ｒ_１及びＲ_２は、それぞれ独立に、水素原子又はメチル基である。Ａ及びＢは炭素数２〜６のアルキレン基を示し、これらは同一であっても相違していてもよく、異なっている場合、−（Ａ−Ｏ）−及び−（Ｂ−Ｏ）−の繰り返し単位は、ブロック構造でもランダム構造でもよい。ｍ１、ｍ２、ｍ３及びｍ４は、０又は正の整数であり、これらの合計は２〜４０である。） As the photopolymerizable monomer (b) used in the present invention, it contains a photopolymerizable monomer represented by the compound represented by the following general formula (II). From the viewpoint of sex.

(R ₁ and R ₂ are each independently a hydrogen atom or a methyl group. A and B each represent an alkylene group having 2 to 6 carbon atoms, which may be the same or different, and are different. The repeating unit of-(A-O)-and-(B-O)-may be a block structure or a random structure, and m1, m2, m3 and m4 are 0 or a positive integer, Is 2 to 40.)

In the compound represented by the general formula (II), A and B are preferably an ethylene group or a propylene group. From the viewpoint of resolution, m1 + m2 + m3 + m4 is preferably 40 or less. Further, m1 + m2 + m3 + m4 is preferably 2 or more, more preferably 4 or more, particularly preferably 10 or more, from the viewpoint of tenting property and followability.
Specific examples of the compound represented by the general formula (II) used in the present invention include polyalkylene glycols each having an average of 2 moles of propylene oxide and an average of 6 moles of ethylene oxide added to both ends of bisphenol A. -Dimethacrylate of polyethylene glycol, dimethacrylate of polyethylene glycol with an average of 5 moles of ethylene oxide added to each end of bisphenol A (NK Nakamura Chemical Co., Ltd. NK ester BPE-500) and Polymethacrylate glycol dimethacrylate (NK ester BPE-20 manufactured by Shin-Nakamura Chemical Co., Ltd.) with an average of 2 moles of ethylene oxide added to both ends of bisphenol A.
0) and dimethacrylate of polyalkylene glycol in which an average of 15 mol of ethylene oxide and an average of 2 mol of propylene oxide are added to both ends of bisphenol A, respectively.

  In the photosensitive resin composition of the present invention, the following compounds other than the photopolymerizable monomer represented by the general formula (II) can be used as the photopolymerizable monomer (b). For example, 1,6-hexanediol di (meth) acrylate, 1,4-cyclohexanediol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 2-di (p -Hydroxyphenyl) propane di (meth) acrylate, glycerol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, polyoxypropyltrimethylolpropane tri (meth) acrylate, polyoxyethyltrimethylolpropane triacrylate, penta Erythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, trimethylolpropane triglycidyl ether tertri (meth) acrylate, bisphenol A jigly Dilether-terdi (meth) acrylate, β-hydroxypropyl-β ′-(acryloyloxy) propyl phthalate, phenoxypolyethylene glycol (meth) acrylate, nonylphenoxypolyethylene glycol (meth) acrylate, nonylphenoxypolyalkylene glycol (meth) Acrylate, polypropylene glycol mono (meth) acrylate, 2,2-bis {(4- (meth) acryloxypolyethoxy) cyclohexyl} propane, polypropylene glycol added with propylene oxide and polyalkylene glycol with ethylene oxide added at both ends And dimethacrylate.

  Moreover, a urethane compound is also mentioned. Examples of the urethane compound include a diisocyanate compound such as hexamethylene diisocyanate, tolylene diisocyanate, or 2,2,4-trimethylhexamethylene diisocyanate, and hydroxyl group in one molecule. And urethane compounds obtained by reaction of a group with a compound having a (meth) acryl group (such as 2-hydroxypropyl acrylate and oligopropylene glycol monomethacrylate). Specifically, there is a reaction product of hexamethylene diisocyanate and oligopropylene glycol monomethacrylate (manufactured by NOF Corporation, Bremma-PP1000).

When the photopolymerizable monomer represented by the general formula (II) is contained, the ratio of the photopolymerizable monomer represented by the general formula (II) to the total of the photosensitive resin composition is 3 to 3 A range of 70% by weight is preferred. From the viewpoint of resolution, it is 3% by mass or more, and from the viewpoint of flexibility of the resist pattern, 70% by mass or less is preferable. More preferably, it is 5-65 mass%. More preferably, it is 5-55 mass%.
Further, the ratio of (b) the photopolymerizable monomer to the total of the photosensitive resin composition is preferably 3% by mass or more from the viewpoint of sensitivity, and preferably 70% by mass or less from the viewpoint of edge fuse. More preferably, it is 10-65 mass%, More preferably, it is 15-55 mass%.

（式中、Ｘ、Ｙ、及びＺはそれぞれ独立に水素、炭素数１から５のアルキル基及びアルコキシ基、並びにハロゲン基のいずれかを表し、ｐ、ｑ、及びｒはそれぞれ独立に１〜５の整数である。） It is a preferable embodiment from the viewpoint of high resolution that the (c) photopolymerization initiator used in the present invention contains a 2,4,5-triarylimidazole dimer represented by the following general formula (I). is there.

(In the formula, X, Y, and Z each independently represent hydrogen, an alkyl group having 1 to 5 carbon atoms, an alkoxy group, or a halogen group, and p, q, and r are each independently 1 to 5) Is an integer.)

  In the compound represented by the above general formula (I), the covalent bond connecting two lophine groups is 1,1′-, 1,2′-, 1,4′-, 2,2′-, Although it is in the 2,4′- or 4,4′-position, a compound in the 1,2′-position is preferred. Examples of 2,4,5-triarylimidazole dimers include 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4,5. -Bis- (m-methoxyphenyl) imidazole dimer, 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer, etc., and in particular, 2- (o-chlorophenyl) ) -4,5-diphenylimidazole dimer is preferred.

The (c) photopolymerization initiator used in the present invention is a system in which 2,4,5-triary-imidazole dimer represented by the general formula (I) and p-aminophenyl ketone are used in combination. Is preferred. Examples of p-aminophenyl ketone include p-aminobenzophenone, p-butylaminoacetophenone, p-dimethylaminoacetophenone, p-dimethylaminobenzophenone, p, p'-bis (ethylamino) benzophenone, p, p'- Bis (dimethylamino) benzophenone [Michler's ketone], p, p′-bis (diethylamino) benzophenone, p, p′-bis (dibutylamino) benzophenone, and the like.
A combination with a pyrazoline compound such as 1-phenyl-3- (4-tert-butyl-styryl) -5- (4-tert-butyl-phenyl) -pyrazoline is also a preferred embodiment.
In addition to the compounds shown above, other photopolymerization initiators can be used in combination. Here, the photopolymerization initiator is a compound that is activated by various actinic rays such as ultraviolet rays and starts polymerization.

Other photopolymerization initiators include, for example, quinones such as 2-ethylanthraquinone and 2-tert-butylanthraquinone, aromatic ketones such as benzophenone, benzoin ethers such as benzoin, benzoin methyl ether and benzoin ethyl ether, Examples include acridine compounds such as 9-phenylacridine, benzyldimethylketal, and benzyldiethylketal.
Further, for example, there are combinations of thioxanthones such as thioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, and tertiary amine compounds such as dimethylaminobenzoic acid alkyl ester compounds.
Further, there are oxime esters such as 1-phenyl-1,2-propanedione-2-O-benzoyloxime and 1-phenyl-1,2-propanedione-2- (O-ethoxycarbonyl) oxime. Further, N-aryl-α-amino acid compounds can also be used, and among these, N-phenylglycine is particularly preferable.

In the photosensitive resin composition of the present invention, when the 2,4,5-triarylimidazole dimer represented by the general formula (I) is contained, the content ratio is 0.1-20. Mass% is preferred. 0.1 mass% or more is preferable from the viewpoint of sensitivity, and 20 mass% or less is preferable from the viewpoint of resolution. As for content, 0.1-15 mass% is more preferable, and 0.1-10 mass% is still more preferable.
In the photosensitive resin composition of the present invention, the proportion of (c) the photopolymerization initiator is preferably 0.1 to 20% by mass. 0.1 mass% or more is preferable from the viewpoint of sensitivity, and 20 mass% or less is preferable from the viewpoint of resolution. As for content, 0.1-15 mass% is more preferable, and 0.1-10 mass% is still more preferable.

  The photosensitive resin composition of the present invention may contain coloring substances such as dyes and pigments. Examples of the coloring material used include fuchsin, phthalocyanine green, olamine base, chalcoxide green S, paramadienta, crystal violet, methyl orange, Nile Bull-2B, Victoria Bull, Malachite Green (Hodogaya Chemical ( Eisen (registered trademark) MALACHITE GREEN), Basic Bull-20, Diamond Green (Hozengaya Chemical Co., Ltd. Eisen (registered trademark) DIAMOND GREEN GH), and the like.

  The photosensitive resin composition in the present invention may contain a coloring dye that develops color when irradiated with light. Examples of the coloring dye used include a combination of a leuco dye or a fluorane dye and a halogen compound. Examples of the leuco dye include tris (4-dimethylamino-2-methylphenyl) methane [leuco crystal violet], tris (4-dimethylamino-2-methylphenyl) methane [leucomalachite green], and the like. .

Halogen compounds include 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, hexachloroethane, triazine compounds and the like. Examples of the triazine compound include 2,4,6-tris (trichloromethyl) -s-triazine and 2- (4-methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine.
Among such coloring dyes, a combination of tribromomethylphenylsulfone and a leuco dye or a combination of a triazine compound and a leuco dye is useful.
The content in the case of containing 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.

In order to improve the thermal stability and storage stability of the photosensitive resin composition in the present invention, it is preferable that the photosensitive resin composition contains the following additives. Examples of such additives include p-methoxyphenol, hydroquinone, pyrogallol, naphthylamine, tert-butylcatechol, cuprous chloride, 2,6-di-tert-butyl-p-cresol, 2,2′- Examples include methylene bis (4-ethyl-6-tert-butylphenol), 2,2′-methylene bis (4-methyl-6-tert-butylphenol), diphenylnitrosamine and the like. Further, as stabilizers, a compound in which propylene oxide is further added to both sides of polypropylene glycol in which an average of 1 mol of propylene oxide is added to both sides of bisphenol A, benzotriazole, carboxybenzotriazole, 1- (2-dialkylamino) carboxybenzo There is triazole, pentaerythritol 3,5-di-t-butyl-4-hydroxyphenylpropionic acid tetraester.
The total amount of the additives is preferably 0.01 to 3% by mass, more preferably 0.05 to 1% by mass. From the viewpoint of imparting storage stability to the photosensitive resin composition, 0.01 mass% or more is preferable, and from the viewpoint of maintaining sensitivity, 3 mass% or less is more preferable.

Furthermore, you may make the photosensitive resin composition of this invention contain a plasticizer etc. as needed. Examples of the plasticizer include phthalic acid esters such as diethyl phthalate, o-toluenesulfonic acid amide, p-toluenesulfonic acid amide, tributyl citrate, triethyl citrate, acetyl triethyl citrate, and acetyl tricitrate tri-n-propyl. Acetyl citrate tri-n-butyl, polypropylene glycol, polyethylene glycol, polyethylene glycol alkyl ether, polypropylene glycol alkyl ether, and the like.
As content in the case of containing a plasticizer etc., it is preferable to contain 5-50 mass% in a photosensitive resin composition, More preferably, it is 5-30 mass%. 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.

<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.
Examples of the solvent include ketones represented by methyl ethyl ketone (MEK), and alcohols represented by methanol, ethanol, and isopropanol. It is preferable to add to the photosensitive resin composition so that the viscosity of the solution of the photosensitive resin composition applied onto the support is 500 to 4000 mPa at 25 ° C.

<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 is peeled off and exposed to active light through a photomask. The exposure amount is determined from the light source illuminance and the exposure time. You may measure using a photometer.
In the exposure process, a maskless exposure method may be used. In maskless 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.

<Conductor Pattern Manufacturing Method / Printed Wiring Board Manufacturing Method>
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 substrate having concave / convex pattern>
When the photosensitive resin laminate of the present invention is used as a dry film resist to process a substrate by sandblasting, glass or a glass coated with a rib paste is used as the substrate, and the method described above on the substrate In the same manner, the photosensitive resin laminate is laminated, exposed and developed. 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 blasting material used for the above-mentioned sandblasting process may be a known material, for example, 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 the embodiment of the present invention will be described in more detail by way of examples.

Below, the preparation method of the sample for evaluation of an Example and a comparative example, the evaluation method about the obtained sample, and an evaluation result are shown.
1. Production of Evaluation Sample The photosensitive resin laminates in Examples and Comparative Examples were produced as follows.
<Preparation of photosensitive resin laminate>
Prepare the compounds shown in Table 1, thoroughly stir and mix the photosensitive resin composition of the composition ratio shown in Table 2, and apply uniformly to the surface of a 20 μm thick polyethylene terephthalate film as a support using a bar coater, The photosensitive resin layer was formed by drying for 4 minutes in a dryer at 95 ° C. The thickness of the photosensitive resin layer was 40 μm.
In Table 1, Table 2, and Table 3, MEK represents methyl ethyl ketone, and the mass parts of P-1 to P-12 in Table 2 and Table 3 are values including MEK.
Next, a 25 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.

<Board surface preparation>
2. (2), (4) The evaluation substrate 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 twice).
<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 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>
A mask film necessary for evaluation is placed on a polyethylene terephthalate film, which is a support, on a photosensitive resin layer, and a 21-step tablet made by Stöffer is 7 steps by an ultra-high pressure mercury lamp (OMW Seisakusho, HMW-201KB). The exposure amount was as follows.
<Development>
After the polyethylene terephthalate film is peeled off, a 1 mass% Na ₂ CO ₃ aqueous solution at 30 ° C. is sprayed for a predetermined time using an alkali developing machine (produced by Fuji Kiko Co., Ltd., a dry film developing machine), and an unexposed portion of the photosensitive resin layer Was dissolved and removed in a time twice the minimum image time. 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>
The developed substrate was etched with a salt copper etching apparatus (manufactured by Tokyo Chemical Industry Co., Ltd.) at 3 mol / l hydrochloric acid, 250 g / l cupric chloride at 50 ° C. for 1.3 times the minimum etching time. At this time, the time when the copper foil on the substrate was completely dissolved and removed was defined as the minimum etching time.
<Resist stripping>
The cured resist was peeled off by spraying a 3% by mass aqueous sodium hydroxide solution heated to 50 ° C. onto the evaluation substrate after development.

2. Evaluation Method (1) Evaluation of Aggregability A photosensitive layer (resist layer) having a thickness of 40 μm and an area of 0.16 m ^{2 in} the photosensitive resin laminate is dissolved in 200 ml of a 1% by mass Na ₂ CO ₃ aqueous solution, and a circulation spray. Spraying was performed using an apparatus at a spray pressure of 0.1 MPa for 3 hours. Thereafter, the developer was allowed to stand for 1 day, and the generation of aggregates was observed. When a large amount of agglomerates are generated, powdery or oily substances are observed at the bottom and side surfaces of the spray device. In addition, aggregates may float in the developer. A composition having good developer cohesiveness does not generate these aggregates at all, or even if they are generated, they can be easily washed away with a small amount of water. The state of occurrence of aggregates was ranked by visual observation as follows.
A: No agglomerates are generated. O: There is no agglomerates at the bottom or side of the spray device, but a very small amount of agglomerates that can be visually confirmed are observed in the developer, but they are easily washed away when washed with water.
X: Aggregates are floating in the bottom or part of the side surface of the spray device and the developer. Even if it is washed with water, everything cannot be washed away.
XX: Aggregates are observed in the entire spray apparatus, and the aggregates are floating in the developer. It is impossible to wash everything away with water, and most of it remains.

(2) Follow-up evaluation Lamination, exposure, development, etching, and peeling were performed on a copper-clad laminate using a commercially available DFR to form a circular depression (pit) having a diameter of 310 μm and a depth of about 10 μm.
A photopolymerizable resin layer was laminated on this pit substrate, and the diameter of air remaining inside the pit without being able to follow the photopolymerizable resin layer was measured and ranked as follows. It is determined that the smaller the air diameter, the better the followability.
A: Air diameter of less than 120 μm B: Air diameter of 120 μm or more and less than 140 μm X: Air diameter of 140 μm or more and less than 160 μm
XX: Air diameter 160μm or more

(3) Evaluation of edge fuse property The photosensitive resin laminate was stored in a roll form at 20 ° C. and a humidity of 50%, and was evaluated by the following ranking depending on whether or not the photosensitive resin composition exudes from the roll end face.
◎: Can be stored for 30 days or more without exudation from the end face ○: Can be stored for 20 days or more but less than 30 days without exudation from the end face ×: 15 days or more but less than 20 days without exudation from the end face XX : Less than 15 days can be stored without bleeding from the end face

(4) Resolution Evaluation The substrate for resolution evaluation that had passed 15 minutes after the lamination was exposed with a line pattern having a ratio of 1: 1 between the exposed area and the unexposed area. Development was performed with a development time twice as long as the minimum development time, and the minimum mask width in which a cured resist line was normally formed was defined as a resolution value, and the resolution was ranked as follows.
◎: Resolution value of 35 μm or less ○: Resolution value of more than 35 μm and 40 μm or less ×: Resolution value of more than 40 μm, 45 μm or less XX: Resolution value of more than 45 μm

  According to the present invention, it is suitable as an etching resist or a plating resist in the fields of production of printed wiring boards, flexible wiring boards, lead frames, semiconductor packages and the like, and precision metal processing.

Claims (11)

With respect to the total sum of the photosensitive resin composition, (a) it is 100 to 550 with a carboxyl group content of acid equivalent, 30 to 80% by weight of benzyl (meth) acrylate as a copolymer component as a copolymer component, 2 -Resin for binders containing 3 to 60% by mass of ethylhexyl (meth) acrylate as a copolymer component and having a weight average molecular weight of 5,000 to 500,000: 20 to 90% by mass, (b) Photopolymerizable monomer: A photosensitive resin composition comprising 3 to 70% by mass and (c) a photopolymerization initiator: 0.1 to 20% by mass. The photosensitive resin composition according to claim 1, wherein the photopolymerization initiator (c) contains a 2,4,5-triarylimidazole dimer represented by the following general formula (I). object.

(In the formula, X, Y, and Z each independently represent hydrogen, an alkyl group having 1 to 5 carbon atoms, an alkoxy group, or a halogen group, and p, q, and r are each independently 1 to 5) Is an integer.) The photosensitive resin composition of Claim 1 or 2 containing the compound represented by the following general formula (II) as said (b) photopolymerizable monomer.

(R ₁ and R ₂ are each independently a hydrogen atom or a methyl group. A and B each represent an alkylene group having 2 to 6 carbon atoms, and these may be the same or different. The repeating unit of-(A-O)-and-(B-O)-may be a block structure or a random structure, and m1, m2, m3 and m4 are 0 or a positive integer, Is 2 to 40.) The photosensitive resin laminated body obtained by laminating | stacking on the support body the photosensitive resin composition as described in any one of Claims 1-3 as a photosensitive resin composition layer. A method for forming a resist pattern, comprising: laminating the photosensitive resin laminate according to claim 4 on a substrate, exposing the laminate to ultraviolet light, and then removing an unexposed portion by development. 6. The resist pattern forming method according to claim 5 , wherein in the exposure step, exposure is performed without using a photomask. A method for producing a conductor pattern, comprising using a metal plate or a metal-coated insulating plate as a substrate, and etching or plating a substrate on which a resist pattern is formed by the method according to claim 5 or 6 . A method for producing a printed wiring board, comprising using a metal-coated insulating plate as a substrate, etching or plating a substrate on which a resist pattern is formed by the method according to claim 5 or 6 , and peeling the resist pattern. A metal plate used as a substrate, the substrate formed with the resist pattern by a method according to claim 5 or 6, and etching method of a lead frame, characterized in that the resist pattern is peeled off. The wafer having circuits formed is finished as LSI as the substrate, the substrate formed with the resist pattern by a method according to claim 5 or 6, and plating, a method of manufacturing a semiconductor package, characterized in that the resist pattern is peeled off . A concavo-convex pattern characterized by using a glass or glass coated with a rib paste as a substrate, processing a substrate on which a resist pattern is formed by the method according to claim 5 or 6 by a sandblasting method, and peeling the resist pattern. The manufacturing method of the base material which has.