JP2010091789A - Photosensitive resin composition, photosensitive element using the composition, method for producing resist pattern and method for manufacturing printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive resin composition which includes an effect of making stripped chips smaller and is excellent in sensitivity, resolution-adhesion, plating resistance and scum dispersibility, and to provide a photosensitive element using the composition, a method for producing a resist pattern and a method for manufacturing a printed wiring board. <P>SOLUTION: The photosensitive resin composition includes a component (polymerizable monomer) of a binder polymer (A), an ethylenically unsaturated photopolymerizable monomer (B), a photopolymerization initiator (C) and a sensitizer, wherein the component of the binder polymer (A) (1) includes methacrylic acid, its content being 18-23 mass%, (2) includes both ethyl acrylate and butyl acrylate, and (3) does not contain styrene or another aromatic compound (polymerizable monomer). The photosensitive element, the method for producing a resist pattern and the method for manufacturing a printed wiring board using the composition are also provided. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a photosensitive resin composition, a photosensitive element using the composition, a method for producing a resist pattern, and a method for producing a printed wiring board.

  Conventionally, in the field of printed wiring board production, as a resist material used for etching (tenting) and plating, a photosensitive resin composition and a photosensitive element obtained by using a support and a protective film are widely used. ing.

  Printed wiring boards are made by laminating a photosensitive element on a normal (chemical or physical) polished copper substrate, pattern exposure, removing unexposed portions with a developer, and etching (tenting) or plating treatment. Is applied to form a pattern, and then the cured portion is peeled off from the substrate (see, for example, Patent Document 1).

However, if the peeling piece (resist piece size after peeling) is large in this peeling process, the peeling piece gets entangled with the carrying roll and spray nozzle of the peeling machine, causing problems such as abnormal conveyance and reduced spray pressure. Alternatively, the peeling piece reattaches on the substrate, and as a result, there arises a problem that the peeling remains.
The photosensitive element is required to divide the peeling piece (to reduce the size of the resist piece after peeling) for the above-mentioned problem.

JP 2006-323004 A

  The present invention has an effect of subdividing the peeled pieces, and has a sensitivity, resolution and adhesion, and further excellent in plating resistance and scum dispersibility, a photosensitive element using this composition, It is an object of the present invention to provide a method for producing a resist pattern and a method for producing a printed wiring board.

  The present invention provides (A) a binder polymer component (polymerizable monomer) having (1) methacrylic acid and a content of 18 to 23% by mass, (2) ethyl acrylate and It has both butyl acrylate and (3) does not contain styrene and an aromatic compound (polymerizable monomer). The component (A) of the binder polymer is further combined with (B) an ethylenic group. The present invention relates to a photosensitive resin composition comprising a saturated photopolymerizable monomer, (C) a photopolymerization initiator and a sensitizer.

Moreover, this invention relates to the photosensitive element formed by apply | coating said photosensitive resin composition on a support body, and drying.
In the present invention, the above photosensitive element is laminated so that the photosensitive resin composition layer is in close contact with the circuit forming substrate, irradiated with actinic rays in an image form, and the exposed portion is photocured, The present invention relates to a method for producing a resist pattern, wherein unexposed portions are removed by development.

  Furthermore, the present invention relates to a method for manufacturing a printed wiring board, wherein the circuit forming substrate in the resist pattern manufactured as described above is etched (tented) or plated.

  The photosensitive resin composition of the present invention, the photosensitive element using this composition, the method for producing a resist pattern, and the method for producing a printed wiring board have the effect of subdividing the release pieces.

Hereinafter, the best mode for carrying out the invention will be described in detail.
In the present invention, (meth) acrylic acid means acrylic acid and its corresponding methacrylic acid, (meth) acrylate means acrylate and its corresponding methacrylate, and (meth) acryloyl group means acryloyl. Means a group and the corresponding methacryloyl group.

  The photosensitive resin composition of the present invention has (1) methacrylic acid as a component (polymerizable monomer) of (A) a binder polymer, and the content thereof is 18 to 23% by mass, (2) It has both ethyl acrylate and butyl acrylate, (3) It does not contain styrene and other aromatic compounds (polymerizable monomers), and the component of this (A) binder polymer And (B) an ethylenically unsaturated photopolymerizable monomer, (C) a photopolymerization initiator and a sensitizer.

  The (A) binder polymer can be produced, for example, by radical polymerization of a polymerizable monomer. As the polymerizable monomer, in order to subdivide the release pieces, the polymerizable monomer has (1) methacrylic acid, and the content thereof is 18 to 23% by mass, (2) Having both ethyl acrylate and butyl acrylate, (3) not containing styrene and other aromatic compounds (polymerizable monomers), other examples include acrylamide, acrylonitrile, vinyl-n -Esters of vinyl alcohol such as butyl ether, (meth) acrylic acid alkyl ester, (meth) acrylic acid tetrahydrofurfuryl ester, (meth) acrylic acid dimethylaminoethyl ester, (meth) acrylic acid diethylaminoethyl ester, (meth) Glycidyl acrylate, 2,2,2-trifluoroethyl (meth) acrylate Rate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, (meth) acrylic acid, α-bromo (meth) acrylic acid, α-chloro (meth) acrylic acid, β-furyl (meth) acrylic acid , Maleic acid, maleic anhydride, maleic acid monoester such as monomethyl maleate, monoethyl maleate, monoisopropyl maleate, fumaric acid, cinnamic acid, α-cyanocinnamic acid, itaconic acid, crotonic acid, propiolic acid, etc. Is mentioned. Examples of the (meth) acrylic acid alkyl ester include, for example, the general formula (I)

（式中、Ｒ^１は水素原子又はメチル基を示し、Ｒ^２は水素原子又は炭素数１〜１２のアルキル基を示す。）
で表される化合物、これらの化合物のアルキル基に水酸基、エポキシ基、ハロゲン基等が置換した化合物などが挙げられる。

(In the formula, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms.)
And compounds in which a hydroxyl group, an epoxy group, a halogen group or the like is substituted on the alkyl group of these compounds.

Examples of the alkyl group having 1 to 12 carbon atoms represented by R ² in the general formula (I) include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, Nonyl group, decyl group, undecyl group, dodecyl group and structural isomers thereof can be mentioned.

  Examples of the monomer represented by the general formula (I) include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and (meth) acrylic. Pentyl acid, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, methyl methacrylate (meth) acrylate, ethyl hydroxide (meth) acrylate , (Meth) acrylic acid propyl hydroxide, (meth) acrylic acid butyl hydroxide, and the like. These can be used alone or in combination of two or more.

  The methacrylic acid is preferably contained in an amount of 18 to 23% by mass, more preferably 19 to 22% by mass, as a copolymer component, from the standpoint of fragmentation of peeled pieces and plating resistance. If the content is less than 18% by mass, the peeled pieces tend not to be fragmented (the peeled piece size increases), and if it exceeds 23% by weight, the plating resistance tends to be lowered.

  These binder polymers are used alone or in combination of two or more. As a binder polymer in the case of using two or more types in combination, for example, two or more types of binder polymers comprising different copolymerization components, two or more types of binder polymers having different weight average molecular weights, and two or more types of binder polymers having different degrees of dispersion are used. Examples thereof include a binder polymer. A polymer having a multimode molecular weight distribution described in JP-A-11-327137 can also be used.

  As the (B) ethylenically unsaturated photopolymerizable monomer, a compound obtained by reacting a polyhydric alcohol with an α, β-unsaturated carboxylic acid, 2,2-bis (4-((meth) acryloxypolyethoxy) ) Phenyl) propane, 2,2-bis (4-((meth) acryloxypolypropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypolybutoxy) phenyl) propane, 2,2 -A compound obtained by reacting an α, β-unsaturated carboxylic acid with a bisphenol A-based (meth) acrylate compound such as bis (4-((meth) acryloxypolyethoxypolypropoxy) phenyl) propane or a glycidyl group-containing compound , Urethane monomers such as (meth) acrylate compounds having a urethane bond in the molecule, nonylphenoxypolyethyleneoxyacrylate Phthalic compounds such as γ-chloro-β-hydroxypropyl-β ′-(meth) acryloyloxyethyl-o-phthalate, β-hydroxyalkyl-β ′-(meth) acryloyloxyalkyl-o-phthalate, (Meth) acrylic acid alkyl ester and the like can be mentioned, but a bisphenol A-based (meth) acrylate compound or a (meth) acrylate compound having a urethane bond in the molecule is preferably an essential component. These may be used alone or in combination of two or more.

  Examples of the (C) photopolymerization initiator and sensitizer include acridine or an acridine compound having at least one acridinyl group in the molecule, benzophenone, N, N′-tetramethyl-4,4′-diaminobenzophenone N, N′-tetraalkyl-4,4′-diaminobenzophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, 2-methyl-1- [ Aromatic ketones such as 4- (methylthio) phenyl] -2-morpholino-propanone-1, quinones such as alkylanthraquinones, benzoin ether compounds such as benzoin alkyl ether, benzoin compounds such as benzoin and alkylbenzoin, benzyldimethyl ketal, etc. A benzyl derivative of 2- (o-chlorophene) ) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4,5-di (methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-diphenylimidazole 2,4,5-tria such as dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer HABI (hexaarylbisimidazole) such as a reel imidazole dimer, N-phenylglycine, an N-phenylglycine derivative, a coumarin compound, an onium salt, and the like can be given. These may be used alone or in combination of two or more.

  The blending amount of the (A) binder polymer is preferably 40 to 80 parts by mass and more preferably 50 to 70 parts by mass with respect to 100 parts by mass of the total amount of the components (A) and (B). preferable. If the blending amount is less than 40 parts by mass, the photocured product tends to be brittle, and when used as a photosensitive element, the coating properties tend to be inferior, and if it exceeds 80 parts by mass, the photosensitivity tends to be insufficient. .

    The blending amount of the (B) ethylenically unsaturated photopolymerizable monomer is preferably 20 to 60 parts by mass, and 30 to 50 parts by mass with respect to 100 parts by mass of the total amount of the component (A) and the component (B). More preferably, it is a part. If this amount is less than 20 parts by mass, the photosensitivity tends to be insufficient, and if it exceeds 60 parts by mass, the photocured product tends to be brittle.

  The blending amount of the (C) photopolymerization initiator and sensitizer is preferably the amount when the absorbance of the resist is 0.2 to 1.5, more preferably 0.3 to 1.0, More preferably, it becomes 0.4-0.8. If the absorbance of this resist is less than 0.2, the photosensitivity tends to be insufficient, and if it exceeds 1.5, the absorption on the surface of the composition is increased during exposure and the internal photocuring is insufficient. Tend to be.

  In the photosensitive resin composition, if necessary, a photopolymerizable compound having at least one cationically polymerizable cyclic ether group in the molecule, a cationic polymerization initiator, a dye such as malachite green, tribromophenylsulfone, Photochromic agents such as leuco crystal violet, thermochromic inhibitors, plasticizers such as p-toluenesulfonamide, pigments, fillers, antifoaming agents, flame retardants, stabilizers, adhesion promoters, leveling agents, peeling accelerators In addition, an antioxidant, a fragrance, an imaging agent, a thermal crosslinking agent and the like can be contained in an amount of about 0.01 to 20 parts by mass with respect to 100 parts by mass of the total amount of the component (A) and the component (B). These may be used alone or in combination of two or more.

  The photosensitive resin composition is dissolved in a solvent such as methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N, N-dimethylformamide, propylene glycol monomethyl ether or a mixed solvent thereof as necessary. And can be applied as a solution having a solid content of about 30 to 60% by mass.

  The photosensitive resin composition is not particularly limited, but is coated as a liquid resist on a metal surface such as copper, a copper-based alloy, iron, and an iron-based alloy, dried, and then covered with a protective film as necessary. Or used in the form of a photosensitive element.

  Moreover, although the thickness of the photosensitive resin composition layer changes with uses, it is preferable that it is about 1-100 micrometers by the thickness after drying. In the case of using a liquid resist coated with a protective film, examples of the protective film include polymer films such as polyethylene and polypropylene.

  The photosensitive element can be obtained, for example, by applying and drying a photosensitive resin composition on a polymer film such as polyethylene terephthalate, polypropylene, polyethylene, or polyester as a support.

The application can be performed by a known method such as a roll coater, a comma coater, a gravure coater, an air knife coater, a die coater, or a bar coater.
Moreover, drying can be performed at 40 to 150 ° C. for about 1 to 30 minutes.
Further, the amount of the remaining organic solvent in the photosensitive resin composition layer is preferably 2% by mass or less from the viewpoint of preventing diffusion of the organic solvent in the subsequent step.

  The thickness of these polymer films is preferably 1 to 100 μm. One of these polymer films may be laminated on both sides of the photosensitive resin composition layer as a support for the photosensitive resin composition layer, and the other as a protective film for the photosensitive resin composition. As the protective film, those having a smaller adhesive force between the photosensitive resin composition layer and the protective film than the adhesive force between the photosensitive resin composition layer and the support are preferable, and a film having a low fish eye is preferable.

In addition to the photosensitive resin composition layer, the support and the protective film, the photosensitive element may have an intermediate layer or protective layer such as a cushion layer, an adhesive layer, a light absorption layer, or a gas barrier layer. .
The photosensitive element is stored, for example, as it is or after a protective film is further laminated on the other surface of the photosensitive resin composition layer and wound around a cylindrical core.

In addition, it is preferable to wind up so that a support body may become the 1st outer side at this time. An end face separator is preferably installed on the end face of the roll-shaped photosensitive element roll from the viewpoint of end face protection, and a moisture-proof end face separator is preferably installed from the viewpoint of edge fusion resistance.
Moreover, as a packing method, it is preferable to wrap and package in a black sheet with low moisture permeability.

  Examples of the winding core include plastics such as polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, and ABS resin (acrylonitrile-butadiene-styrene copolymer).

In producing a resist pattern using the photosensitive element, when the protective film is present, the protective film is removed and then the photosensitive resin composition layer is heated to about 70 to 130 ° C. For example, a method of laminating by pressure bonding to a circuit forming substrate at a pressure of about 0.1 to 1 MPa (about 1 to 10 kgf / cm ² ) may be mentioned, and the lamination may be performed under reduced pressure. The surface to be laminated is usually a metal surface, but is not particularly limited.

  The photosensitive resin composition layer thus laminated is irradiated with actinic rays in an image form through a negative or positive mask pattern. As the light source of the actinic light, a known light source, for example, a light source that effectively emits ultraviolet light, visible light, or the like, such as a carbon arc lamp, a mercury vapor arc lamp, a high-pressure mercury lamp, or a xenon lamp is used.

  Next, after exposure, when a support is present on the photosensitive resin composition layer, the support is removed, and then wet development or dry development with a developer such as an alkaline aqueous solution, an aqueous developer, or an organic solvent. The resist pattern can be manufactured by removing the unexposed portion with development or the like and developing.

  Examples of the alkaline aqueous solution include a dilute solution of 0.1 to 5% by mass sodium carbonate, a dilute solution of 0.1 to 5% by mass potassium carbonate, a dilute solution of 0.1 to 5% by mass sodium hydroxide, and the like. It is done.

The pH of the alkaline aqueous solution is preferably in the range of 9 to 11, and the temperature is adjusted according to the developability of the photosensitive resin composition layer.
Further, a surfactant, an antifoaming agent, an organic solvent, or the like may be mixed in the alkaline aqueous solution. Examples of the development method include a dip method, a spray method, brushing, and slapping.

As the treatment after development, the resist pattern may be further cured and used by heating at about 60 to 250 ° C. or exposure at about 0.2 to 10 J / cm ² as necessary.
For the etching of the metal surface performed after development, for example, a cupric chloride solution, a ferric chloride solution, an alkaline etching solution, or the like can be used.

  When a printed wiring board is produced using the photosensitive element of the present invention, the surface of the circuit forming substrate is treated by a known method such as etching (tenting) or plating using the developed resist pattern as a mask.

Examples of the plating method include copper plating, solder plating, tin plating, nickel plating, and gold plating.
Next, the resist pattern can be peeled off with a stronger alkaline aqueous solution than the alkaline aqueous solution used for development, for example.

As said strong alkaline aqueous solution, 1-10 mass% sodium hydroxide aqueous solution, 1-10 mass% potassium hydroxide aqueous solution, or an amine peeling liquid etc. are used, for example.
The said peeling liquid is used individually or in combination of 2 or more types.

Examples of the peeling method include an immersion method and a spray method.
The printed wiring board on which the resist pattern is formed may be a multilayer printed wiring board or may have a small diameter through hole.

Hereinafter, the present invention will be described by way of examples.
Examples 1 and 2 and Comparative Examples 1 to 4
The materials shown in Tables 1 and 2 were blended to obtain a solution.

Methacrylic acid / Methyl methacrylate / Ethyl acrylate / Butyl acrylate (20/50/25/5 (weight ratio))

＊（単位はｇ）

* (Unit: g)

＊（単位はｇ）

* (Unit: g)

In addition, the material used in Table 1 and Table 2 is shown below.
BPE-500: a compound in which m + n = 10 (average value) in the following general formula (II) (trade name, manufactured by Shin-Nakamura Chemical Co., Ltd.)

  UA-13: EO represented by the following general formula (III), PO-modified urethane dimethacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name)

TMPT-21: Compound represented by n ₁ + n ₂ + n ₃ = 21 (average value) in the following general formula (IV) (trade name, manufactured by Hitachi Chemical Co., Ltd.)

  M-113: Nonylphenyl polyethylene-modified acrylate represented by the following general formula (V) (trade name, manufactured by Toagosei Co., Ltd.)

  F-804S: 1- [N, N-bis (2-ethylhexyl) aminomethyl] -5-carboxybenzotrizole (trade name, manufactured by Chiyoda Chemical Co., Ltd.) represented by the following general formula (VI)

  Next, the obtained photosensitive resin composition solution was uniformly applied onto a 16 μm thick polyethylene terephthalate film (trade name HTR-02-16, manufactured by Teijin Ltd.), and a hot air convection dryer at 100 ° C. And dried with a polyethylene protective film (manufactured by Tamapoly Co., Ltd., trade name NF-13) to obtain a photosensitive element. The film thickness after drying of the photosensitive resin composition layer was 38 μm.

  Next, the copper surface of a copper-clad laminate (made by Hitachi Chemical Co., Ltd., trade name MCL-E-67), which is a glass epoxy material in which copper foil (thickness 35 μm) is laminated on both sides, has a brush equivalent to # 600 Polishing using a polishing machine (manufactured by Sankei Co., Ltd.), washing with water, drying with air flow, heating the obtained copper-clad laminate to 80 ° C, and peeling off the protective film on the copper surface The photosensitive resin composition layer was laminated at a speed of 1.5 m / min using a 120 ° C. heat roll.

  Next, using a light exposure machine (trade name HMW-201GX, manufactured by Oak Manufacturing Co., Ltd.) having a high-pressure mercury lamp, a stove 21-step tablet was placed on the test piece as a negative and exposed.

  Next, the polyethylene terephthalate film is peeled off, and a 1% by mass sodium carbonate aqueous solution is sprayed at 30 ° C. for twice the minimum development time to remove unexposed portions, and then the light formed on the copper clad laminate The photosensitivity of the photosensitive resin composition was evaluated by measuring the number of steps of the step tablet of the cured film. The minimum development time was measured as the time when the unexposed resist was completely removed by the development process.

Photosensitivity indicates the amount of exposure energy (mJ / cm ² ) at which the number of remaining steps after development (development time = minimum development time × 2) is 8.0 in a stove 21-step tablet. The smaller the exposure energy amount, the higher the photosensitivity.

  As for resolution, a photo tool having a stove 21-step tablet and a photo tool having a wiring pattern with a space width / line width of 8/400 to 47/400 (unit: μm) are closely attached as a negative for resolution evaluation. In a 21-step tablet of fur, exposure was performed with an energy amount such that the number of remaining step steps after development (development time = minimum development time × 2) was 8.0.

  Here, the resolution was evaluated based on the smallest value of the space width between the line widths in which the unexposed portion could be removed cleanly by the development (development time = minimum development time × 2) process. The smaller the numerical value, the better the resolution evaluation.

  Adhesion is achieved by adhering a phototool having a stove 21-step tablet and a phototool having a wiring pattern with a line width / space width of 8/400 to 47/400 (unit: μm) as a negative for adhesion evaluation. In a stove 21-step tablet, exposure was performed with an energy amount such that the number of remaining step steps after development (development time = minimum development time × 2) was 8.0.

  Here, the adhesion is that after development (development time = minimum development time × 2), there is no part where the resist forming the line is firmly adhered to the substrate, and the line is meandering, Evaluation was based on the smallest value of the line width that was not bent. The smaller the numerical value, the better the adhesion evaluation.

The peeled piece shape (size) was determined by using a peeling evaluation negative [PET negative: 60 × 45 mm square (solid: no pattern)] and exposure (the number of remaining step steps after development in a stove 21-step tablet was 8). 0.0 (exposure energy amount), development (development time = minimum development time × 2) and immersing the substrate (60 × 45 mm square) in a beaker (peeling solution: 3.0 mass% NaOH aqueous solution, 50 ° C.) Evaluation was performed by observing the shape (size) after stirring for 30 seconds after completion of peeling. [This strip shape (size) varies depending on the pattern width, the spray pressure of the stripper, etc.]
The tin plating resistance was evaluated based on the evaluation criteria shown in Table 4 by performing tin plating under the conditions shown in Table 3.

Scum dispersibility was evaluated by the following method.
First, the photosensitive film developer 0.6mil · ^m 2 / l, which corresponds to 1.5 times the photosensitive film dissolution amount customers recommended conditions in a developer ^{(0.4mil · m 2 / l)} (1 (Mass% Na ₂ CO ₃ aqueous solution), this solution was circulated and stirred for 90 minutes with a small developing machine, and the amount of scum (oil) generated on the surface was evaluated according to the dispersibility evaluation criteria shown in Table 5.

以上の結果をまとめて表６に示す。

The results are summarized in Table 6.

  As shown in Table 6, it is clear that Examples 1 and 2 have the effect of subdividing the peeling pieces, and that the sensitivity, resolution / adhesion, plating resistance and scum dispersibility are good. is there.

Claims (4)

  (A) As a component (polymerizable monomer) of the binder polymer, (1) methacrylic acid is included, and the content thereof is 18 to 23% by mass; (2) ethyl acrylate and butyl acrylate Both have (3) styrene and an aromatic compound (polymerizable monomer), and (B) ethylenically unsaturated photopolymerizability is further added to this (A) binder polymer component. A photosensitive resin composition comprising a monomer, (C) a photopolymerization initiator and a sensitizer.   A photosensitive element obtained by coating the photosensitive resin composition according to claim 1 on a support and drying.   The photosensitive element according to claim 2 is laminated on a circuit-forming substrate so that the photosensitive resin composition layer is in close contact, irradiated with an actinic ray in an image form, and an exposed portion is photocured to form an unexposed portion. A process for producing a resist pattern, characterized in that is removed by development.   A method for producing a printed wiring board, comprising etching or plating a circuit forming substrate in the resist pattern produced in claim 3.