JP2004341478A - Photosensitive element, resist pattern forming method using the same, method for manufacturing printed circuit board and photosensitive resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive element which suppresses filiform undeveloped parts (deficiency of resolution) which occurs in a part where the interval between resist patterns is narrow while maintaining superior resolution, and can form a resist pattern whose side face shape is good. <P>SOLUTION: The photosensitive element has on a resin film a photosensitive layer comprising a photosensitive resin composition containing (A) a binder polymer, (B) a photopolymerizable compound having an ethylenically unsaturated bond and (C) a photopolymerization initiator, wherein the component (A) includes a low molecular weight binder polymer whose weight average molecular weight is 10,000 to 30,000 and the resin film has a haze of ≤1%. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

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

  Conventionally, in the field of manufacturing printed wiring boards and in the field of precision processing of metals, a photosensitive layer or a photosensitive element covered with a protective film obtained by laminating this on a resin film has been widely used as a resist material used for etching, plating, and the like. ing.

  As a method of using the photosensitive element, first, after the protective film is peeled off, pressure-sensitive bonding (lamination) is performed so that the photosensitive layer directly contacts the base material (such as a copper substrate). Next, a patterned photo tool is brought into close contact with the light-transmitting film, irradiated (exposed) with actinic rays such as ultraviolet rays, and then a developer is sprayed to remove an unexposed portion to form a resist pattern ( Development).

  As a developing solution for removing the unexposed portion, it is usually possible to use a developing solution having a capability of dissolving or dispersing the photosensitive layer to some extent, and at present, an alkali developing type using an aqueous solution of sodium carbonate or an aqueous solution of sodium hydrogen carbonate is used. It has become mainstream.

  By the way, in recent years, with the increase in density and resolution of printed wiring boards, the contact area between the patterned photosensitive layer and the base material has been reduced, so in the development, etching or plating process, The resist material is required to have mechanical strength, chemical resistance, flexibility and the like, as well as adhesion between the photosensitive layer and the substrate and resolution of the photosensitive layer.

  In order to improve the resolution of the photosensitive layer, it is effective to make the photosensitive layer thinner. However, when a certain circuit thickness (copper thickness or the like) is required at the time of manufacturing a printed wiring board, the etching method is affected by side etching at the time of etching, so that the resist line in the thin line portion is likely to be missing. It has been difficult to achieve both high circuit thickness and narrow circuit width, and to realize high resolution printed wiring boards. Further, in the plating method, when the photosensitive layer is made thinner, it is difficult to obtain a required circuit thickness, and thus there is a limit to increasing the resolution of the printed wiring board.

  Attempts have been made to achieve higher resolution of printed wiring boards by methods other than thinning the photosensitive layer, and the resin film is peeled off before exposure, and a photo tool is directly placed on the photosensitive resin composition. There is known a method for making the close contact. However, usually, the photosensitive layer has a certain degree of adhesiveness so as to be in close contact with the substrate, and when this method is applied, the photo tool and the photosensitive layer are in close contact with each other, and it is difficult to remove the photo tool, thereby increasing workability. There have been problems such as a decrease in sensitivity, contamination of the photo tool by the photosensitive resin composition, and a decrease in sensitivity due to the influence of oxygen inhibition.

  Therefore, as an attempt to improve this method, a method of using two or more photosensitive layers and a non-adhesive resin layer as a layer directly in contact with the photo tool has been performed (for example, see Patent Documents 1 to 3). However, this method requires time and effort to coat the photosensitive layer in order to make it multi-layered, and is not sufficiently effective in reducing the sensitivity. It was difficult to achieve.

Further, as a method for achieving higher density and higher resolution of a printed wiring board, a method of manufacturing a printed wiring board by a semi-additive method has been attracting attention. This method prints by sequentially forming an ultra-thin conductor layer by electroless plating or the like on a substrate, forming a resist pattern, plating, stripping the resist, and quick etching (unnecessary removal of the ultra-thin conductor layer). This is a method for forming a wiring board. According to this method, the influence of side etching can be reduced, and a favorable circuit can be obtained. However, when a conventional photosensitive element is used by the semi-additive method, a problem that the side surface of the resist pattern becomes rough occurs, and it is difficult to obtain a plated circuit having a good side surface shape, and the printed wiring board is difficult to obtain. There is a limit to the increase in the density and resolution of the image.
JP-A-61-31855 JP-A-1-221735 JP-A-2-230149

  Then, when the present inventors tried to form a resist pattern using a conventional photosensitive element, in addition to the above-described problem, a thread-like development residue (insufficient resolution) occurred in a narrow space between the resist patterns. And that the side surfaces of the resist pattern become rough, and found that such a problem is an obstacle to sufficiently achieving high density and high resolution of the printed wiring board. .

  The present invention has been made in view of the above circumstances, and has excellent resolution, reduces thread-like development residue (insufficient resolution) occurring in a narrow space between resist patterns, and reduces the shape of the resist pattern side surface. It is an object of the present invention to provide a photosensitive element capable of forming a good resist pattern. Another object of the present invention is to provide a method for forming a resist pattern and a method for manufacturing a printed wiring board using such a photosensitive element, and a photosensitive resin composition constituting such a photosensitive element.

  In order to achieve the above object, the present invention comprises a photosensitive resin composition containing (A) a binder polymer, (B) a photopolymerizable compound having an ethylenically unsaturated bond, and (C) a photopolymerization initiator. A photosensitive element having a photosensitive layer on a resin film, wherein the component (A) contains a low molecular weight binder polymer having a weight average molecular weight of 10,000 to 30,000, and the resin film has a haze. Is 1% or less.

  Here, "containing a low molecular weight binder polymer having a weight average molecular weight of 10,000 to 30,000" means that when two or more binder polymers are used as the component (A), the weight average molecular weight is 10,000. It means that it contains at least about 30,000 low molecular weight binder polymers. In the present invention, it is preferable that the low molecular weight binder polymer is contained most in the component (A) on a weight basis.

  Further, the present invention provides a photosensitive layer comprising a photosensitive resin composition containing (A) a binder polymer, (B) a photopolymerizable compound having an ethylenically unsaturated bond, and (C) a photopolymerization initiator. The photosensitive element provided thereon, wherein the component (A) has a weight average molecular weight of 10,000 to 30,000, and the resin film has a haze of 1% or less. I do.

  Each of the photosensitive elements can form a resist pattern having a good side shape while having excellent resolution, and furthermore, it is possible to sufficiently reduce the occurrence of a thread-like phenomenon residue (insufficient resolution). is there. In addition, it is possible to sufficiently achieve high density and high resolution of the printed wiring board, which cannot be achieved conventionally. It is considered that such an effect is achieved when the photosensitive layer is made of the above-mentioned component (A) and the haze of the resin film is 1% or less.

  For example, when only the photosensitive layer satisfies the above-described conditions or when only the resin film satisfies the above-mentioned conditions, it is necessary to simultaneously achieve both the reduction of the thread-like development residue and the formation of a resist pattern having a good side shape. And it is difficult to achieve high density and high resolution of the printed wiring board.

  Further, the present invention provides a laminating step of laminating the photosensitive element, a photosensitive layer and a resin film in this order on a circuit-forming substrate, and irradiating an active ray to a predetermined portion of the photosensitive layer through the resin film. A method of forming a resist pattern, comprising: an exposure step of forming a photo-cured portion in the photosensitive layer; and a developing step of removing the photosensitive layer other than the photo-cured portion, and formation of the resist pattern. Provided is a method for manufacturing a printed wiring board, characterized by etching or plating a circuit forming substrate on which a resist pattern is formed by a method.

  The method for forming a resist pattern and the method for manufacturing a printed wiring board according to the present invention use the photosensitive element according to the present invention, so that a thread-like development residue that occurs in a narrow portion between resist patterns is reduced, and the side shape is good. It is possible to form a resist pattern, thereby making it possible to increase the density and resolution of the printed wiring board.

  Further, the photosensitive resin composition of the present invention comprises (A) a binder polymer having a weight average molecular weight of 10,000 to 30,000, (B) a photopolymerizable compound having an ethylenically unsaturated bond, and (C) a photopolymerizable compound. Contains a polymerization initiator. By forming a photosensitive layer using such a photosensitive resin composition, the above-described photosensitive element can be obtained.

ADVANTAGE OF THE INVENTION According to this invention, while being excellent in resolution and adhesiveness, it becomes possible to provide the photosensitive element which can form the resist pattern with which the thread-like development residue is sufficiently reduced and a side surface shape is favorable. . Further, according to the present invention, it is possible to provide a method for forming a resist pattern using such a photosensitive element, thereby manufacturing a printed wiring board capable of increasing the density and resolution of the printed wiring board. It is possible to provide a method.

  Hereinafter, the present invention will be described in detail with reference to preferred embodiments. In the present invention, (meth) acrylic acid means acrylic acid or methacrylic acid, and the same applies to (meth) acrylate and the like.

(Photosensitive element)
First, the resin film according to the photosensitive element of the present invention will be described.

  The resin film is not particularly limited as long as the resin has a haze of 1% or less. Examples of the resin film include a film made of a heat-resistant and solvent-resistant polymer such as polyethylene terephthalate, polypropylene, polyethylene, and polyester. Terephthalate films are preferred. These resin films may have a single-layer structure or a multilayer structure in which films having a plurality of compositions are laminated.

  Here, the haze of the resin film needs to be 1% or less, preferably 0.5% or less, and more preferably 0.3% or less. If the haze exceeds 1%, the above-described effects of the present invention cannot be sufficiently obtained, and the side surface shape of the resist pattern deteriorates and the resolution decreases. The haze can be measured according to JIS K 7105, and can be measured with a commercially available turbidity meter such as NDH-1001DP (trade name, manufactured by Nippon Denshoku Industries Co., Ltd.). .

  The thickness of the resin film is preferably from 5 to 20 μm, more preferably from 8 to 18 μm, and particularly preferably from 10 to 16 μm. When the thickness is less than 5 μm, the resin film tends to be broken when the resin film is peeled before development, and when the thickness is more than 20 μm, the resolution is reduced or the side shape of the resist pattern is deteriorated. They tend to be inexpensive.

  Next, the photosensitive layer according to the photosensitive element of the present invention will be described.

As described above, the photosensitive layer comprises the following components (A) to (C):
(A) a binder polymer (B) a photopolymerizable compound having an ethylenically unsaturated bond (C) a photosensitive resin composition containing a photopolymerization initiator; The weight average molecular weight of the molecular weight binder polymer is from 10,000 to 30,000, or the weight average molecular weight of the entire component (A) is from 10,000 to 30,000.

  Here, the weight average molecular weight of the low molecular weight binder polymer in the component (A) or the weight average molecular weight of the entire component (A) is preferably 15,000 to 25,000, and 20,000 to 25,000. 000 is more preferable. When the weight average molecular weight is out of the above range, the above-described effects of the present invention cannot be sufficiently obtained, and when the weight average molecular weight is less than the lower limit, the problem that the photosensitive layer becomes brittle further occurs. If the upper limit is exceeded, the occurrence of thread-like development residue becomes remarkable. As the component (A), both the weight average molecular weight of the low molecular weight binder polymer and the weight average molecular weight of the entire component (A) are 10,000 to 30,000 (more preferably 15,000 to 25,000). 000, more preferably 20,000 to 25,000). The weight average molecular weight can be measured by gel permeation chromatography (GPC) (converted with standard polystyrene).

  Further, the photosensitive element of the present invention can exhibit the effects of the present invention more sufficiently by satisfying the above-described respective ranges of the haze of the resin film and the weight average molecular weight in combination with each other. Become. That is, for example, it is most preferable that the haze of the resin film is 0.3% or less, and the weight average molecular weight of the low molecular weight binder polymer and the component (A) as a whole is 20,000 to 25,000. In this case, the photosensitive element of the present invention can obtain more excellent resolution, can have a very good resist pattern side surface shape, and can sufficiently reduce the occurrence of a thread-like phenomenon residue. Thus, it is possible to more reliably realize higher density and higher resolution of the printed wiring board.

  Examples of the binder polymer used as the component (A) include an acrylic resin, a styrene resin, an epoxy resin, an amide resin, an amide epoxy resin, an alkyd resin, and a phenol resin. Of these, acrylic resins are preferred from the viewpoint of alkali developability. These can be used alone or in combination of two or more.

  (A) The binder polymer can be produced, for example, by radically polymerizing a monomer (polymerizable monomer). Examples of the monomer include styrene; polymerizable styrene derivatives such as vinyltoluene, α-methylstyrene, p-methylstyrene, and p-ethylstyrene; acrylamide; acrylonitrile; esters of vinyl alcohol such as vinyl-n-butyl ether. Alkyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, glycidyl (meth) acrylate, 2, 2, 2-trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, (meth) acrylic acid, α-bromo (meth) acrylic acid, α-chloro (meth) acrylic acid, β-furyl (meta) Substituted (meth) acrylic acids such as crylic acid and β-styryl (meth) acrylic acid; maleic acid; maleic anhydride; maleic acid monoesters such as monomethyl maleate, monoethyl maleate and monoisopropyl maleate; fumaric acid; Cinnamic acid, α-cyanocinnamic acid, itaconic acid, crotonic acid, propiolic acid and the like. These can be used alone or in combination of two or more.

  Examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, and (meth) Examples include hexyl acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and structural isomers thereof. These can be used alone or in combination of two or more.

  (A) The binder polymer preferably has a carboxyl group from the viewpoint of alkali developability, and can be produced, for example, by radically polymerizing a monomer having a carboxyl group and another monomer. As the monomer having a carboxyl group, (meth) acrylic acid is preferable.

  Further, (A) the binder polymer preferably contains a styrene-based monomer from the viewpoint of adhesion and chemical resistance (plating resistance). Here, the styrene-based monomer includes styrene and a styrene derivative (examples of the styrene derivative are as described above).

  Further, it is preferable that all of the binder polymer (A) is composed of a copolymer of a styrene-based monomer, (meth) acrylic acid and an alkyl (meth) acrylate, whereby the photosensitive element of the present invention is more excellent. Resolution can be obtained, the side surface shape of the resist pattern can be made very good, and the occurrence of the remaining thread-like phenomenon tends to be more sufficiently reduced.

  Furthermore, the content of the styrene-based monomer is preferably 20 to 40% by weight, more preferably 20 to 35% by weight, and more preferably 25 to 30% by weight based on the total weight of the monomer. Particularly preferred. When the content is in the above range, the photosensitive layer can have sufficient flexibility, and the occurrence of brittleness, chipping, and the like tends to be sufficiently reduced. In addition, the photosensitive element of the present invention can obtain more excellent resolution, can have a very good resist pattern side surface shape, and can sufficiently reduce the occurrence of a thread-like phenomenon residue. It tends to be.

  (A) The acid value of the binder polymer is preferably from 30 to 200 mgKOH / g, more preferably from 45 to 150 mgKOH / g. If the acid value is less than 30 mgKOH / g, the developing time tends to be long. If it exceeds 200 mgKOH / g, the developing solution resistance of the photocured resist by exposure tends to decrease. Further, when the acid value of the low molecular weight binder polymer is in the above range, it tends to be possible to sufficiently reduce the occurrence of thread-like development residue. Here, when the binder polymer (A) is composed of a plurality of components, the acid value means an average value (acid value as a whole). When solvent development is performed as the development step, the amount of the monomer having a carboxyl group is preferably adjusted to a small amount.

  Further, if necessary, the binder polymer (A) may have a photosensitive group.

  These (A) binder polymers can be used alone or in combination of two or more. When two or more binder polymers are used in combination, examples thereof include two or more binder polymers composed of different monomers, and two or more binder polymers having different weight average molecular weights. Further, a binder polymer having a multi-mode molecular weight distribution described in JP-A-11-327137 can also be used.

  In the present invention, when the binder polymer (A) is used in combination of two or more components, a low molecular weight binder polymer having a weight average molecular weight of 10,000 to 30,000 is contained in the component (A), or (A) It is necessary that the weight average molecular weight of the entire binder polymer be 10,000 to 30,000. When the (A) binder polymer containing two or more component bander polymers is used, the low molecular weight binder polymer and the high molecular weight binder polymer having a weight average molecular weight of more than 30,000 may be used in combination. Preferably, the polymer has a weight average molecular weight in the range of 10,000 to 30,000.

  (B) The photopolymerizable compound having an ethylenically unsaturated bond preferably contains a compound having 4 to 40 oxyalkylene units having 2 to 6 carbon atoms in the molecule. By containing such a compound as the component (B), the compatibility with the low molecular weight binder polymer in the component (A) can be improved, and the effects of the present invention as described above can be reliably obtained. Tend.

  Here, examples of the oxyalkylene unit having 2 to 6 carbon atoms include an oxyethylene unit, an oxypropylene unit, an oxyisopropylene unit, an oxybutylene unit, an oxypentylene unit, and an oxyhexylene unit. An oxyethylene unit or an oxyisopropylene unit is preferred from the viewpoint of plating property.

  Among these photopolymerizable compounds, a bisphenol A-based (meth) acrylate compound or a polyalkylene glycol di (meth) acrylate is particularly preferably used because the effects of the present invention can be more reliably obtained. it can.

As the bisphenol A-based (meth) acrylate compound, for example, a compound represented by the following general formula (I) is preferably exemplified.

In the general formula (I), R ¹ and R ² represent a hydrogen atom or a methyl group, and preferably a methyl group. In the general formula (I), X ¹ and X ² represent an alkylene group having 2 to 6 carbon atoms, preferably an ethylene group or a propylene group, and more preferably an ethylene group. In the general formula (I), p and q each represent a positive integer selected so that p + q = 2 to 20, and the value of p + q is preferably 3 to 17, more preferably 4 to 15. It is particularly preferably 4 to 14, particularly preferably 4 to 10, very preferably 4 to 8, and most preferably 4 to 6. If the value of p + q is less than 2, the compatibility with the binder polymer (A) is reduced, and the photosensitive element tends to peel off when the photosensitive element is laminated on the circuit-forming substrate. The resist image tends to peel off during development, and the plating resistance to solder plating and the like tends to decrease. In any case, the resolution of the photosensitive element tends to decrease, and it tends to be difficult to achieve high density and high resolution of the printed wiring board.

  Examples of the alkylene group having 2 to 6 carbon atoms include an ethylene group, a propylene group, an isopropylene group, a butylene group, a pentylene group, and a hexylene group. Is preferred.

  The aromatic ring in the general formula (I) may have a substituent, and examples of the substituent include a halogen atom, an alkyl group having 1 to 20 carbon atoms, and a cyclo group having 3 to 10 carbon atoms. An alkyl group, an aryl group having 6 to 18 carbon atoms, a phenacyl group, an amino group, an alkylamino group having 1 to 10 carbon atoms, a dialkylamino group having 2 to 20 carbon atoms, a nitro group, a cyano group, a carbonyl group, a mercapto group, An alkylmercapto group having 1 to 10 carbon atoms, an allyl group, a hydroxyl group, a hydroxyalkyl group having 1 to 20 carbon atoms, a carboxyl group, a carboxyalkyl group having 1 to 10 carbon atoms in the alkyl group, and having 1 to 10 carbon atoms in the alkyl group. An acyl group having 10 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxycarbonyl group having 1 to 20 carbon atoms, an alkylcarbonyl group having 2 to 10 carbon atoms, and an alkyl group having 2 to 10 carbon atoms. Alkenyl group, N- alkylcarbamoyl group or a group containing a heterocyclic ring having 2 to 10 carbon atoms, or an aryl group substituted by these substituents. The above substituents may form a condensed ring, and the hydrogen atoms in these substituents may be substituted with the above substituents such as halogen atoms. When the number of substituents is two or more, the two or more substituents may be the same or different.

  Examples of the compound represented by the general formula (I) include 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane and 2,2-bis (4-((meth) acrylic). Roxypolypropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypolybutoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypolyethoxypolypropoxy) phenyl) Bisphenol A (meth) acrylate compounds such as propane are exemplified.

  As 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane, for example, 2,2-bis (4-((meth) acryloxydiethoxy) phenyl) propane, 2,2- Bis (4-((meth) acryloxytriethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytetraethoxy) phenyl) propane, 2,2-bis (4-((meth) (Acryloxypentaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyhexaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyheptaethoxy) phenyl) propane 2,2-bis (4-((meth) acryloxyoctaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxynonaethoxy) ) Phenyl) propane, 2,2-bis (4-((meth) acryloxydecaethoxy) phenyl), 2,2-bis (4-((meth) acryloxyundecaethoxy) phenyl), 2,2- Bis (4-((meth) acryloxide decaethoxy) phenyl), 2,2-bis (4-((meth) acryloxytridecaethoxy) phenyl), 2,2-bis (4-((meth) acryl) Roxytetradecaethoxy) phenyl), 2,2-bis (4-((meth) acryloxypentadecaethoxy) phenyl), 2,2-bis (4-((meth) acryloxyhexadecaethoxy) phenyl), etc. And 2,2-bis (4- (methacryloxypentaethoxy) phenyl) propane is commercially available as BPE-500 (product name, manufactured by Shin-Nakamura Chemical Co., Ltd.). , And the 2,2-bis (4- (methacryloxy pentadecanoyl) phenyl) is, BPE-1300 is commercially available as (trade name, manufactured by Shin-Nakamura Chemical Co., Ltd.). These can be used alone or in combination of two or more.

  Examples of 2,2-bis (4-((meth) acryloxypolyethoxypolypropoxy) phenyl) propane include 2,2-bis (4-((meth) acryloxydiethoxyoctapropoxy) phenyl) propane, Examples thereof include 2,2-bis (4-((meth) acryloxytetraethoxytetrapropoxy) phenyl) propane and 2,2-bis (4-((meth) acryloxyhexaethoxyhexapropoxy) phenyl) propane. These can be used alone or in combination of two or more.

As the polyalkylene glycol di (meth) acrylate, for example, a compound represented by the following general formula (II) is preferably exemplified.

In the general formula (II), R ³ and R ⁴ represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and are preferably a methyl group. In the above general formula (II), Y ¹ , Y ² and Y ³ represent an alkylene group having 2 to 6 carbon atoms, and are preferably an ethylene group or a propylene group. In the above general formula (II), s, t and u each represent an integer of 0 to 30 selected so that s + t + u = 4 to 40, and the value of s + t + u is preferably 5 to 30; More preferably, it is particularly preferably 10 to 15. If the value of s + t + u is less than 4, the boiling point of the compound tends to decrease, and the odor of the photosensitive layer tends to increase. If the value exceeds 40, the concentration of photoreactive sites per unit weight decreases, so that it is practical. Sensitivity tends not to be obtained.

Further, oxyalkylene units (-(Y ¹ -O) s-,-(Y ² -O) t-, and-(Y ³ -O) u-) in the general formula (II) are, for example, When an oxyethylene unit and an oxypropylene unit are included, when a plurality of oxyethylene units and oxypropylene units are present, the plurality of oxyethylene units and oxypropylene units do not need to be present in a continuous block, and may be present at random. .

  Further, when the oxyalkylene unit is an oxyisopropylene unit, the secondary carbon of the propylene group may be bonded to an oxygen atom, or the primary carbon may be bonded to an oxygen atom.

［式中、Ｒ^３及びＲ^４は水素原子又は炭素数１〜３のアルキル基を示し、ＥＯはオキシエチレン単位を示し、ＰＯはオキシプロピレン単位を示し、ｍ^１、ｍ^２及びｎ^１はｍ^１＋ｍ^２＋ｎ^１＝４〜４０となるように選ばれる１〜３０の整数を示す。］

［式中、Ｒ^３及びＲ^４は水素原子又は炭素数１〜３のアルキル基を示し、ＥＯはオキシエチレン単位を示し、ＰＯはオキシプロピレン単位を示し、ｍ^３、ｎ^２及びｎ^３はｍ^３＋ｎ^２＋ｎ^３＝４〜４０となるように選ばれる１〜３０の整数を示す。］

［式中、Ｒ^３及びＲ^４は水素原子又は炭素数１〜３のアルキル基を示し、ＥＯはオキシエチレン単位を示し、ＰＯはオキシプロピレン単位を示し、ｍ^４及びｎ^４はｍ^４＋ｎ^４＝４〜４０となるように選ばれる１〜３０の整数を示す。］ Preferred examples of the compound represented by the general formula (II) include compounds represented by the following general formulas (III) to (V). These can be used alone or in combination of two or more.

[Wherein, R ³ and R ⁴ represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, EO represents an oxyethylene unit, PO represents an oxypropylene unit, and m ¹ , m ² and n ¹ represent m. ¹ + ^m 2 ⁺ n indicates the 30 integer selected so as to be 1 = 4 to 40. ]

[Wherein, R ³ and R ⁴ represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, EO represents an oxyethylene unit, PO represents an oxypropylene unit, and m ³ , n ² and n ³ represent m ³ + ⁿ indicates the 30 integer selected to 2 ⁺ n 3 = 4~40 become so. ]

[Wherein, R ³ and R ⁴ represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, EO represents an oxyethylene unit, PO represents an oxypropylene unit, and m ⁴ and n ⁴ are m ⁴ + n ⁴ = 1 to 30 selected to be 4 to 40. ]

  Examples of the alkyl group having 1 to 3 carbon atoms in the general formulas (III) to (V) include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group.

Further, the total number of repeating oxyethylene units (m ¹ + m ² , m ³ and m ⁴ ) in the general formulas (III) to (V) is preferably an integer of 1 to 30, and preferably an integer of 1 to 10. Is more preferably an integer of 4 to 9, and most preferably an integer of 5 to 8. If the number of repetitions exceeds 30, tent reliability and resist shape tend to deteriorate.

The total number of repeating oxypropylene units (n ¹ , n ² + n ³ and n ⁴ ) in the above general formulas (III) to (V) is preferably an integer of 1 to 30 and is an integer of 5 to 20. More preferably, it is particularly preferably an integer of 8 to 16, and most preferably an integer of 10 to 14. If the number of repetitions exceeds 30, the resolution will deteriorate and sludge will tend to be generated.

Specific examples of the compound represented by the general formula (III) include, for example, vinyl in which R ³ and R ⁴ are methyl groups, m ¹ + m ² = 4 (average value), and n ¹ = 12 (average value). Compound (manufactured by Hitachi Chemical Co., Ltd., trade name: FA-023M) and the like.

Specific examples of the compound represented by the general formula (IV) include, for example, vinyl in which R ³ and R ⁴ are methyl groups, m ³ = 6 (average value), and n ² + n ³ = 12 (average value). Compound (manufactured by Hitachi Chemical Co., Ltd., trade name: FA-024M) and the like.

Specific examples of the compound represented by the general formula (V) include, for example, a vinyl compound in which R ³ and R ⁴ are a hydrogen atom, m ⁴ = 1 (average value), and n ⁴ = 9 (average value) ( Shin Nakamura Chemical Industry Co., Ltd., sample name: NK ester HEMA-9P) and the like. These can be used alone or in combination of two or more.

  As the component (B), in addition to the photopolymerizable compound having an ethylenically unsaturated bond as described above, it is preferable to further include another photopolymerizable compound having an ethylenically unsaturated bond. Nonylphenoxypolyalkyleneoxy (meth) acrylates such as nonylphenoxypolyethyleneoxy (meth) acrylate, nonylphenoxypolypropyleneoxy (meth) acrylate, nonylphenoxypolyethyleneoxypolypropyleneoxy (meth) acrylate, and γ-chloro-β-hydroxypropyl- phthalic acid compounds such as β ′-(meth) acryloyloxyethyl-o-phthalate and β-hydroxyalkyl-β ′-(meth) acryloyloxyalkyl-o-phthalate; and alkyl (meth) acrylates. .

  In addition, the photosensitive resin composition of the present invention can contain a photopolymerizable compound other than the above-described photopolymerizable compound. For example, a glycidyl group-containing compound is reacted with an α, β-unsaturated carboxylic acid. And urethane monomers such as (meth) acrylate compounds having a urethane bond in the molecule.

  (C) As a photopolymerization initiator, for example, benzophenone, N, N'-tetraalkyl-4,4'-diaminobenzophenone such as N, N'-tetramethyl-4,4'-diaminobenzophenone (Michler's ketone), Aromatic ketones such as 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propanone-1; Quinones such as alkylanthraquinone; benzoin ether compounds such as benzoin alkyl ether; benzoin compounds such as benzoin and alkylbenzoin; benzyl derivatives such as benzyldimethyl ketal; 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer , 2- (o-chlorophenyl) -4,5-di (meth (Phenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p- 2,4,5-triarylimidazole dimer such as methoxyphenyl) -4,5-diphenylimidazole, acridine such as 9-phenylacridine, 1,7-bis (9,9'-acridinyl) heptane Derivatives, N-phenylglycine, N-phenylglycine derivatives, coumarin compounds and the like. Further, the substituents of the aryl groups of the two 2,4,5-triarylimidazoles may be the same to give a target compound, or different asymmetric compounds may be given. From the viewpoints of adhesion and sensitivity, 2,4,5-triarylimidazole dimer is more preferable. These can be used alone or in combination of two or more.

  The compounding amount of the (A) binder polymer is preferably from 40 to 70 parts by weight, more preferably from 50 to 60 parts by weight, based on 100 parts by weight of the total amount of the components (A) and (B). If the amount is less than 40 parts by weight, the resolution and the photosensitivity tend to be insufficient, and if it exceeds 70 parts by weight, the photocured product tends to become brittle.

  (B) The amount of the photopolymerizable compound having an ethylenically unsaturated bond is preferably 30 to 60 parts by weight, and more preferably 40 to 50 parts by weight, based on 100 parts by weight of the total amount of the components (A) and (B). More preferably, it is part by weight. If the amount is less than 30 parts by weight, the resolution and light sensitivity tend to be insufficient, and if it exceeds 60 parts by weight, the photocured product tends to be brittle.

  The compounding amount of the photopolymerization initiator (C) is preferably 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight, based on 100 parts by weight of the total of the components (A) and (B). Is more preferable. If the amount is less than 0.1 part by weight, the photosensitivity tends to be insufficient. If the amount exceeds 20 parts by weight, the absorption on the surface of the photosensitive resin composition during exposure increases, and Photocuring tends to be insufficient.

  If necessary, the photosensitive resin composition may contain a photopolymerizable compound (oxetane compound or the like) having at least one cationically polymerizable cyclic ether group in the molecule, a cationic polymerization initiator, or a dye such as malachite green. , Photochromic agents such as tribromophenylsulfone and leucocrystal violet, thermal coloring inhibitors, plasticizers such as p-toluenesulfonamide, pigments, fillers, defoamers, flame retardants, stabilizers, adhesion promoters, A leveling agent, a peeling accelerator, an antioxidant, a fragrance, an imaging agent, a thermal crosslinking agent, and the like are each contained in an amount of about 0.01 to 20 parts by weight based on 100 parts by weight of the total amount of the components (A) and (B). be able to. These can be used alone or in combination of two or more.

  Further, if necessary, the photosensitive resin composition may be 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. It can be dissolved and applied as a solution having a solid content of about 30 to 60% by weight.

  The photosensitive layer according to the photosensitive element of the present invention can be formed by applying the above-described photosensitive resin composition on a resin film and removing the solvent. Here, as a coating method, for example, a known method such as a roll coater, a comma coater, a gravure coater, an air knife coater, a die coater, and a bar coater can be adopted. The removal of the solvent can be performed by, for example, treating at a temperature of 70 to 150 ° C. for about 5 to 30 minutes. The amount of the residual organic solvent in the photosensitive layer is preferably 2% by weight or less from the viewpoint of preventing the diffusion of the organic solvent in a later step.

  The thickness of the photosensitive layer formed in this manner varies depending on the application, but is preferably about 1 to 100 μm as a thickness after drying.

  As described above, the photosensitive element of the present invention can be obtained by laminating a photosensitive layer on a resin film. Further, a protective film may be further laminated on the surface of the photosensitive layer opposite to the surface in contact with the resin film.

  As this protective film, it is preferable to use a film in which the adhesive force between the photosensitive layer and the protective film is smaller than the adhesive force between the photosensitive layer and the resin film, and a low fisheye film It is preferable to use Specifically, for example, an inactive polyolefin film such as polyethylene and polypropylene may be mentioned, but a polyethylene film is preferable from the viewpoint of releasability from the photosensitive layer.

  Further, the photosensitive element of the present invention may have an intermediate layer or a protective layer such as a cushion layer, an adhesive layer, a light absorbing layer, and a gas barrier layer, in addition to the photosensitive layer, the resin film, and the protective film.

  The photosensitive element of the present invention can be stored, for example, as it is or in a state where a laminate of protective films is wound around a cylindrical core. At this time, it is preferable that the resin film is wound up in a roll shape so that the resin film is on the outside. Further, it is preferable to install an end face separator on the end face of the photosensitive element wound up in a roll shape from the viewpoint of protection of the end face, and it is preferable to install a moisture-proof end face separator from the viewpoint of edge fusion resistance. Further, as a packing method, it is preferable to wrap in a black sheet having low moisture permeability.

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

(Method of forming resist pattern)
The method of forming a resist pattern of the present invention includes a laminating step of laminating the photosensitive element of the present invention on a circuit-forming substrate in the order of a photosensitive layer and a resin film, and activating light rays of the photosensitive layer through the resin film. A method comprising irradiating a predetermined portion to form a photo-cured portion on the photosensitive layer, and a developing step of removing the photosensitive layer other than the photo-cured portion.

  In the laminating step, as a method of laminating the photosensitive layer on the circuit forming substrate, if a protective film is present on the photosensitive layer, after removing the protective film, the photosensitive layer is heated to about 70 to 130 ° C. For example, by laminating the circuit-forming substrate by pressure bonding at a pressure of about 0.1 to 1 MPa while heating, and laminating under reduced pressure. The surface on which the circuit forming substrate is laminated is usually a metal surface, but is not particularly limited. Further, in order to further improve the lamination property, a pre-heat treatment of the circuit formation substrate may be performed.

  Next, in the exposure step, the photosensitive layer on which the lamination is completed in the lamination step is irradiated with actinic rays imagewise through the negative or positive mask pattern and the resin film to form a photocured portion in the photosensitive layer. Done by As the light source of the actinic ray, a known light source, for example, a carbon arc lamp, a mercury vapor arc lamp, a high-pressure mercury lamp, a xenon lamp, or the like that effectively emits ultraviolet light or visible light is used. It is also used for the laser direct writing exposure method.

  Next, in the developing step, after the exposure step, the resin film is removed, and an unexposed portion (light-cured portion) is removed by wet development using a developer such as an alkaline aqueous solution, an aqueous developer, or an organic solvent, or dry development. To develop a resist pattern.

  Examples of the alkaline aqueous solution include a dilute solution of 0.1 to 5% by weight of sodium carbonate, a dilute solution of 0.1 to 5% by weight of potassium carbonate, and a dilute solution of 0.1 to 5% by weight of sodium hydroxide. . 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 layer. Further, a surfactant, an antifoaming agent, an organic solvent and the like may be mixed in the alkaline aqueous solution. Examples of the developing method include a dip method, a spray method, brushing, and slapping.

Further, as a treatment after the development step, the resist pattern may be further cured by heating at about 60 to 250 ° C. or exposing at about 0.2 to 10 J / cm ² as necessary.

(Method of manufacturing printed wiring boards)
The method of manufacturing a printed wiring board of the present invention is performed by etching or plating a circuit-forming substrate on which a resist pattern has been formed by the above-described method of forming a resist pattern of the present invention. Here, the etching or plating of the circuit-forming substrate is performed by etching or plating the surface of the circuit-forming substrate by a known method using the developed resist pattern as a mask.

  As an etchant used for etching, for example, a cupric chloride solution, a ferric chloride solution, an alkali etching solution, or the like can be used.

  Examples of the plating include copper plating, solder plating, nickel plating, and gold plating.

  After etching or plating, the resist pattern can be stripped with, for example, a more alkaline aqueous solution than the alkaline aqueous solution used for development. As the strong alkaline aqueous solution, for example, a 1 to 10% by weight aqueous solution of sodium hydroxide, a 1 to 10% by weight aqueous solution of potassium hydroxide or the like is used. 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.

  Further, when plating is performed on a circuit-forming substrate including an insulating layer and a conductive layer formed on the insulating layer, it is necessary to remove the conductive layer other than the pattern. Examples of the removing method include a method of lightly etching after removing the resist pattern, a method of performing solder plating or the like following the above-described plating, a method of removing the resist pattern, masking a wiring portion with solder, and then forming a conductive layer. A method using an etching solution capable of etching only the substrate.

  Hereinafter, the present invention will be described more specifically based on Examples and Comparative Examples, but the present invention is not limited to the following Examples.

(Preparation of (A) component)
A polymer obtained by copolymerizing the monomers shown in Table 1 at the weight ratios shown in Table 1 was dissolved in toluene / methylcellosolve (weight ratio: 4/6) so that the solid content was 40% by weight. Thus, (A) components 1 to 4 were obtained. The weight average molecular weight and the acid value of the polymer are as shown in Table 1.

(Preparation of photosensitive composition solution)
Next, the materials shown in Table 2 were blended to obtain a photosensitive resin composition solution.

(Preparation of photosensitive element)
Next, the obtained photosensitive resin composition solution was uniformly coated on a 16 μm-thick polyethylene terephthalate film (PET film) shown in Table 3, and dried with a hot air convection dryer at 100 ° C. for 10 minutes to remove the solvent. After removal, the film was covered with a protective film made of polyethylene (manufactured by Tamapoly Co., Ltd., trade name: NF-15, tensile strength in the longitudinal direction of the film: 16 MPa, tensile strength in the width direction of the film: 12 MPa). 3 and Comparative Examples 1 to 3 were obtained. The thickness of each of the photosensitive layers after drying was 25 μm.

(Production of laminate)
The copper surface of a copper-clad laminate (manufactured by Hitachi Chemical Co., Ltd., trade name: MCL-E-61), which is a glass epoxy material having copper foil (thickness: 35 μm) laminated on both sides, is brushed with a brush equivalent to # 600. This was polished using a polishing machine (manufactured by Sankei Co., Ltd.), washed with water, and then dried in an air stream. The obtained copper-clad laminate was heated to 80 ° C., and the photosensitive element was laminated on the copper surface at a speed of 3 m / min using a heat roll at 120 ° C. while peeling off the protective film. Laminates were obtained by laminating the photosensitive elements of Examples 1 to 3 and Comparative Examples 1 to 3 on a copper-clad laminate. These laminates are used as test pieces in evaluation tests of the respective characteristics of the photosensitive element described below. Unless otherwise specified, a separate test piece is used for each test.

(Light sensitivity test)
A 21-step stofer step tablet was placed as a negative on the PET film of the test piece, and an exposure machine (manufactured by Oak Co., Ltd., trade name: EXM-1201) having a high-pressure mercury lamp was used, and the energy was 60 mJ / cm ² . Exposure was performed so as to obtain the amount. Subsequently, the PET film was peeled off, and a 1% by weight aqueous solution of sodium carbonate at 30 ° C. was sprayed on the photosensitive layer for 30 seconds to remove unexposed portions and develop. Then, the photosensitivity of the photosensitive resin composition was evaluated by measuring the number of steps of the step tablet of the photocurable film formed on the copper-clad laminate. Table 3 shows the results. The light sensitivity is indicated by the number of steps of the step tablet. The higher the number of steps of the step tablet, the higher the light sensitivity.

(Resolution test)
In order to investigate the resolution, a photo tool having a 21-step stofer step tablet and a photo tool having a wiring pattern having a line width / space width of 10/10 to 47/47 (unit: μm) as a resolution evaluation negative were tested. One piece of the PET film was brought into close contact with the PET film and exposed using an exposure machine having a high-pressure mercury lamp with an energy amount such that the number of remaining steps after the development of the 21-step Stofa step tablet was 7.0. Subsequently, the PET film was peeled off, and a 1% by weight aqueous solution of sodium carbonate at 30 ° C. was sprayed on the photosensitive layer for 30 seconds to remove unexposed portions and to perform development. Here, the resolution was evaluated based on the smallest value (unit: μm) of the space width between the line widths where the unexposed portions could be removed cleanly by the development processing. Table 3 shows the results. The smaller the numerical value, the better the evaluation of the resolution. Further, by combining this evaluation or the evaluation described below, it is possible to evaluate whether or not the thread development residue is sufficiently reduced.

(Adhesion test)
In order to examine the adhesion, a photo tool having a 21-step stofer step tablet and a photo tool having a wiring pattern having a line width / space width of 10/400 to 47/400 (unit: μm) as a negative for resolution evaluation were used. The test piece was brought into close contact with the PET film and exposed using an exposure machine having a high-pressure mercury lamp with an energy amount such that the number of remaining steps after the development of the 21-step Stofa step tablet was 7.0. Subsequently, the PET film was peeled off, and a 1% by weight aqueous solution of sodium carbonate at 30 ° C. was sprayed on the photosensitive layer for 30 seconds to remove unexposed portions and develop. Here, the adhesion is that the resist forming the line after development is tightly adhered to the substrate and there is no peeling off, and the line width is such that the line does not meander or bend. The evaluation was made according to the smallest value (unit: μm). Table 3 shows the results. In addition, the evaluation of adhesiveness is a better value as the numerical value is smaller.

(Fine wire plating peeling test)
With respect to the fine wire plating releasability, the laminate after development in the resolution test was used as a test piece. The test piece was immersed in a degreasing bath (PC-455 (25% by weight) manufactured by Meltex Co., Ltd.) for 5 minutes and washed with water. Then, it was immersed in a soft etching bath (150 g / liter of ammonium persulfate) for 2 minutes and washed with water. Further, pretreatment is performed in the order of immersion in a 10% by weight sulfuric acid bath for 1 minute, and a copper sulfate plating bath (copper sulfate pentahydrate 60 g / liter, sulfuric acid 98 ml / liter, sodium chloride 100 mg / liter, basic leveler caparaside) (Atotech Japan Co., Ltd.) 20 ml / liter, brightener Kaparaside Universal (Atotech Japan Co., Ltd.) 3 ml / liter), and copper sulfate plating was performed at room temperature for 35 minutes at 2 A / dm ² . . Then, a 3% by weight aqueous solution of sodium hydroxide was sprayed for 2 minutes, and the fine wire plating releasability was evaluated based on the smallest value of the space width between the plating line widths from which the resist was completely removed. Table 3 shows the results. The smaller the numerical value, the better the evaluation of the fine wire plating releasability.

(Evaluation of resist pattern side shape)
Further, the side surface shape of the resist pattern after development in the resolution test was observed by a scanning electron microscope (SEM), and evaluated according to the following evaluation criteria in three stages of ○, Δ, and ×.
：: Smooth side shape, equal to or higher than the side shape of the resist pattern shown in the SEM photograph in FIG.
×: Rough side shape, roughness equal to or higher than the side shape of the resist pattern shown in the SEM photograph in FIG.
Δ: Side profile with intermediate smoothness between 中間 and ×, comparable to the side profile of the resist pattern shown in the SEM photograph in FIG.

  Table 3 shows the results of evaluating the side surface shape of the resist pattern. Further, it is possible to evaluate whether or not the side shape of the resist pattern is good by such evaluation.

FIG. 9 is a diagram showing a scanning electron micrograph (1,000-fold magnification) of the side surface shape of the resist pattern, which is used as an evaluation standard for ○ in the evaluation of the side surface shape of the resist pattern. FIG. 4 is a view showing a scanning electron micrograph (1,000-fold magnification) of the side surface shape of the resist pattern, which serves as an evaluation standard of Δ in the evaluation of the side surface shape of the resist pattern. FIG. 4 is a diagram showing a scanning electron micrograph (1,000 times magnification) of a side shape of the resist pattern, which is used as an evaluation standard of × in the evaluation of the side shape of the resist pattern.

Claims (12)

A photosensitive element comprising, on a resin film, a photosensitive layer comprising a photosensitive resin composition containing (A) a binder polymer, (B) a photopolymerizable compound having an ethylenically unsaturated bond, and (C) a photopolymerization initiator. And
(A) The photosensitive element characterized in that the component contains a low molecular weight binder polymer having a weight average molecular weight of 10,000 to 30,000, and the resin film has a haze of 1% or less. A photosensitive element comprising, on a resin film, a photosensitive layer comprising a photosensitive resin composition containing (A) a binder polymer, (B) a photopolymerizable compound having an ethylenically unsaturated bond, and (C) a photopolymerization initiator. And
(A) The photosensitive element, wherein the component has a weight average molecular weight of 10,000 to 30,000, and the resin film has a haze of 1% or less. The photosensitive element according to claim 1, wherein the resin film has a thickness of 5 to 20 μm. The photosensitive material according to any one of claims 1 to 3, wherein the component (A) comprises a copolymer of (meth) acrylic acid, an alkyl (meth) acrylate and a styrene monomer. element. The photosensitive element according to any one of claims 1 to 4, wherein the acid value of the component (A) is from 30 to 200 mgKOH / g. The photosensitive element according to any one of claims 1 to 5, wherein the component (B) contains a photopolymerizable compound having 4 to 40 oxyalkylene units having 2 to 6 carbon atoms in the molecule. . The photopolymerizable compound having 4 to 40 oxyalkylene units having 2 to 6 carbon atoms in the molecule is a photopolymerizable compound represented by the following general formula (I) or (II). 6. The photosensitive element according to 6.

[Wherein, R ¹ and R ² are a hydrogen atom or a methyl group, X ¹ and X ² are an alkylene group having 2 to 6 carbon atoms, p and q are positive integers selected so that p + q = 2 to 20, Are respectively shown. ]

[Wherein, R ³ and R ⁴ are a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, Y ¹ , Y ² and Y ³ are an alkylene group having 2 to 6 carbon atoms, and s, t and u are s + t + u = 4 to And an integer of 0 to 30 selected to be 40. ] The photosensitive element according to any one of claims 1 to 7, wherein the component (C) contains a 2,4,5-triarylimidazole dimer. The compounding amount of the component (B) is 30 to 60 parts by weight based on 100 parts by weight of the total amount of the components (A) and (B), and the compounding amount of the component (C) is 9. The photosensitive element according to claim 1, wherein the amount is 0.1 to 20 parts by weight based on 100 parts by weight in total. A laminating step of laminating the photosensitive element according to any one of claims 1 to 9 on a circuit-forming substrate in the order of a photosensitive layer and a resin film,
Actinic light, irradiating a predetermined portion of the photosensitive layer through the resin film, an exposure step of forming a photocured portion in the photosensitive layer,
A developing step of removing the photosensitive layer other than the photocured portion,
A method for forming a resist pattern, comprising: A method for manufacturing a printed wiring board, comprising etching or plating a substrate for circuit formation on which a resist pattern has been formed by the method for forming a resist pattern according to claim 10. A photosensitive composition comprising (A) a binder polymer having a weight average molecular weight of 10,000 to 30,000, (B) a photopolymerizable compound having an ethylenically unsaturated bond, and (C) a photopolymerization initiator. Resin composition.

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