JP2013217954A - Method for forming resist pattern, permanent mask resist and photosensitive resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive resin composition excellent in resolution, fine opening property (resolution of a circular hole), gold plating resistance, solder resistance and HAST resistance, and a method for forming a resist pattern using the composition, and a permanent mask resist obtained by the method.SOLUTION: The method for forming a resist pattern comprises: forming a photosensitive layer comprising the following photosensitive resin composition on a substrate; curing a predetermined part of the photosensitive layer by irradiation with actinic rays; then removing the photosensitive layer other than the predetermined part; and treating the layer with an aqueous solution containing a divalent metal ion. The photosensitive composition comprises (a) a resin having an ethylenically unsaturated group and a carboxyl group, (b) a photopolymerizable monomer having an ethylenically unsaturated group, (c) a photopolymerization initiator, and (d) an epoxy resin having 200 ppm or less of a chlorine content and 500 ppm or less of a hydrolyzable chloride.

Description

  The present invention relates to a resist pattern forming method, a permanent mask resist, and a photosensitive resin composition.

  In recent years, with the reduction in size and weight of digital devices, miniaturization and higher density of circuits formed on a printed wiring board, a semiconductor package substrate, and a flexible wiring board are progressing. For the purpose of protecting these fine and high-density opening patterns, a photosensitive solder resist is used. The solder resist is required to have surface flatness, developability, high resolution, insulation reliability, solder heat resistance, gold plating resistance, and the like.

  As the photosensitive resin composition for solder resist, a liquid photosensitive resin composition is usually used particularly in the field of printed wiring boards. Then, a solder resist is formed from a two-part type photosensitive resin composition obtained by separately dividing a thermosetting epoxy resin and a photosensitive prepolymer containing a carboxyl group for imparting alkali developability. It is common. As the photosensitive prepolymer, an alkali developable photosensitive prepolymer which is obtained by adding acrylic acid to a cresol novolak type epoxy resin and then acid-modifying with an acid anhydride or the like is widely used.

  In the above two-component photosensitive resin composition, the reaction of the carboxyl group of the epoxy resin and the photosensitive prepolymer proceeds even at room temperature, so the storage stability (pot life) after mixing the two components is from several hours to one. The use conditions are limited, such as being short and short and having to be mixed immediately before use. In order to avoid such a problem, a one-component type photosensitive resin composition having a storage stability improved by using a blocked isocyanate compound instead of an epoxy resin as a thermosetting agent has been conventionally used (for example, Patent Documents). 1).

  On the other hand, in recent years, a photosensitive resin composition for a dry film type solder resist has been strongly desired from the viewpoint of improving film thickness uniformity, surface smoothness, thin film forming property, and handleability. According to such a photosensitive resin composition, in addition to the above characteristics, effects such as simplification of a process for forming a solder resist and reduction of a solvent discharge amount at the time of forming the solder resist are obtained.

  So far, various photosensitive resin compositions for dry film type solder resists have been developed. For example, Patent Document 2 discloses a photosensitive film containing a polymer having a carboxyl group, a photopolymerizable compound, a photopolymerization initiator, and a bismaleimide compound. Moreover, in patent document 3, the copolymer obtained by making 0.1-1.2 equivalent primary amine compound react with the anhydride group of a maleic anhydride copolymer, a polymeric compound, and photopolymerization. A photosensitive film containing an initiator is disclosed. Furthermore, in patent document 4, the photosensitive film which prescribed | regulated content of chlorine and hydrolyzable chlorine of both the photosensitive prepolymer and an epoxy resin is disclosed.

  On the other hand, as the diameter of the solder balls is reduced by reducing the pitch of the connection terminals, the solder resist is further required to have a fine aperture (good resolution). In addition, with the narrowing of wiring pitch, improvement in embedding property and HAST resistance is also strongly demanded.

JP 2001-305726 A JP 2004-287267 A JP 2005-316431 A JP 2009-265388 A

  However, when the photosensitive film described in the above-mentioned patent document is used, it is improved in terms of being excellent in all of fine aperture properties, resolution, gold plating resistance, and HAST resistance (highly accelerated stress test, Highly Accelerated Temperature and Humidity Stress Test). There was room for. In particular, the importance of the item of insulation reliability between fine wirings is increasing, and it is 130 ° C. compared to the conventional test in which voltage is applied at 85 ° C., 60% RH, or 85 ° C., 85% RH. , 85% RH and a high test temperature, and the harsh conditions required for the HAST test are required.

  The present invention relates to a photosensitive resin composition excellent in resolution, fine aperture (round hole resolution), gold plating resistance, solder resistance and HAST resistance, and a method for forming a resist pattern using the same. An object is to provide the obtained permanent mask resist.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have determined that the chlorine content of the epoxy resin is not more than a specific value. The present invention was completed by finding that the above-mentioned object was achieved by using a high-purity product and treating with an aqueous solution containing divalent metal ions in the washing water used in forming the resist pattern.

  The present invention provides: [1] On a substrate, (a) a resin having an ethylenically unsaturated group and a carboxyl group, (b) a photopolymerizable monomer having an ethylenically unsaturated group, and (c) a photopolymerization initiator. And (d) an epoxy resin having a chlorine content of 500 ppm or less, and a photosensitive layer comprising a photosensitive resin composition, and after curing a predetermined portion of the photosensitive layer with actinic rays, The present invention relates to a resist pattern forming method in which the photosensitive layer region is removed and processing is performed using an aqueous solution containing divalent metal ions.

Further, the present invention provides [2] The above [1], wherein the divalent metal ion is at least one metal ion selected from Ca ²⁺ , Mg ²⁺ , Sr ²⁺ and Ba ^2+. The present invention relates to a method for forming a resist pattern.

  The present invention also relates to [3] a permanent mask resist produced by the resist pattern forming method described in [1] or [2].

The present invention also provides [4] a photosensitive layer made of a photosensitive resin composition on a substrate, and a predetermined portion of the photosensitive layer is cured with actinic rays, and then the photosensitive layer region other than the predetermined portion is removed. A photosensitive resin composition used in a method for forming a resist pattern, which is treated with an aqueous solution containing a divalent metal ion,
The photosensitive resin composition comprises (a) a resin having an ethylenically unsaturated group and a carboxyl group, (b) a photopolymerizable monomer having an ethylenically unsaturated group, (c) a photopolymerization initiator, d) It relates to a photosensitive resin composition containing an epoxy resin having a chlorine content of 500 ppm or less.

  Using the photosensitive resin composition containing the high-purity epoxy resin of the present invention, exposing with a predetermined opening pattern, developing with a dilute alkaline aqueous solution, treating with an aqueous solution containing divalent metal ions, and curing By doing so, a resist pattern excellent in resolution, fine aperture (round hole resolution), gold plating resistance, solder resistance and HAST resistance can be formed. The permanent mask resist thus obtained has equivalent performance and can form an optimal solder resist for printed wiring boards, semiconductor package substrates, and flexible wiring boards.

  Hereinafter, preferred embodiments of the present invention will be described in detail. In the present invention, (meth) acrylate means acrylate and the corresponding methacrylate, and (meth) acrylic acid means acrylic acid and methacrylic acid.

  The present invention includes (a) a resin having an ethylenically unsaturated group and a carboxyl group, (b) a photopolymerizable monomer having an ethylenically unsaturated group, (c) a photopolymerization initiator, and (d) containing chlorine. An aqueous solution containing a divalent metal ion after exposing a solder resist layer with a predetermined opening pattern using a photosensitive resin composition containing a high-purity epoxy resin having an amount of 500 ppm or less and developing with a dilute alkaline aqueous solution It is related with the formation method of the resist pattern hardened after processing using.

  As a main factor that the HAST resistance is deteriorated, it is largely derived from impurity ions contained in the alkali development type solder resist layer. In particular, monovalent anions have high ionization energy and are likely to be carriers that carry copper ionized by the voltage applied during the insulation test.

  In addition, sodium carbonate or potassium carbonate is generally used as a dilute alkali developer, but monovalent sodium ions and potassium ions contained in these developers are taken into the solder resist layer during the development process. This is also considered as a cause of deterioration of HAST resistance.

  Therefore, as a result of intensive studies, the present inventors have selected a high-purity epoxy resin having a chlorine content of 500 ppm or less as the component (d), and exposed the solder resist layer with a predetermined opening pattern, thereby rarely It discovered that HAST tolerance could be improved by processing using the aqueous solution containing a bivalent metal ion after image development with aqueous alkali solution.

<(A) component; resin having an ethylenically unsaturated group and a carboxyl group>
Examples of the resin having an ethylenically unsaturated group and a carboxyl group as the component (a) of the present invention include a saturated or unsaturated polybasic acid in an esterified product of an epoxy compound (a1) and an unsaturated monocarboxylic acid (a2). An addition reaction product to which an anhydride (a3) has been added can be used. These can be obtained by the following two-step reaction.

  In the first reaction (hereinafter referred to as “first reaction” for convenience), the epoxy compound (a1) and the unsaturated monocarboxylic acid (a2) react. In the next reaction (hereinafter referred to as “second reaction” for convenience), the esterified product produced in the first reaction reacts with the saturated or unsaturated polybasic acid anhydride (a3).

  Although there is no restriction | limiting in particular as said epoxy compound (a1), For example, a bisphenol type epoxy compound, a novolak type epoxy compound, a biphenyl type epoxy compound, and a polyfunctional epoxy compound are mentioned.

  As the bisphenol type epoxy compound, those obtained by reacting bisphenol A type, bisphenol F type and epichlorohydrin are suitable. Specifically, Ciba Geigy GY-260, GY-255, XB-2615, Japan Epoxy Resin Epicoat 828, 1007, 807, etc., bisphenol A type, bisphenol F type, hydrogenated bisphenol A type, amino group-containing Epoxy compounds such as alicyclic or polybutadiene modified are preferably used.

  As the novolak type epoxy compound, those obtained by reacting novolaks obtained by reacting phenol, cresol, halogenated phenol and alkylphenols with formaldehyde in the presence of an acidic catalyst and epichlorohydrin are suitable.

  Examples of the novolak type epoxy compound include YDCN-701, 704, YDPN-638, 602 manufactured by Tohto Kasei Co., Ltd., DEN-431, 439 manufactured by Dow Chemical Company, EPN-1299 manufactured by Ciba Geigy Co., and N manufactured by DIC Corporation. -730, 770, 865, 665, 673, VH-4150, 4240, Nippon Kayaku Co., Ltd. EOCN-120, BREN are mentioned.

  Examples of other epoxy compounds include salicylaldehyde-phenol or cresol type epoxy compounds (Nippon Kayaku Co., Ltd., EPPN502H, FAE2500, etc.), DIC Corporation Epicron 840, 860, 3050, Dow Chemical DER-330, 337, 361 manufactured by Daicel Chemical Industries, Ltd. 2021 manufactured by Daicel Chemical Industries, Ltd., TETRAD-X, C manufactured by Mitsubishi Gas Chemical Co., Ltd., EPB-13, 27 manufactured by Nippon Soda Co., Ltd. may also be used. These may be used alone or in combination of two or more, and a mixture or a block copolymer may be used.

  Examples of the unsaturated monocarboxylic acid (a2) include (meth) acrylic acid, crotonic acid, cinnamic acid, and saturated or unsaturated polybasic acid anhydrides and (meth) acrylates having one hydroxyl group in one molecule. Or the reaction material of the half-ester compound of a saturated or unsaturated dibasic acid and an unsaturated monoglycidyl compound is mentioned. Examples of the reactant include phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, maleic acid, succinic acid, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and tris (hydroxyethyl) isocyanurate. Examples thereof include reactants obtained by reacting di (meth) acrylate, glycidyl (meth) acrylate and the like in an equimolar ratio by a conventional method. These unsaturated monocarboxylic acids can be used alone or in combination. Among these, acrylic acid is preferable.

  Examples of the saturated or unsaturated polybasic acid anhydride (a3) include succinic anhydride, maleic anhydride, tetrahydrophthalic anhydride, phthalic anhydride, methyltetrahydrophthalic anhydride, ethyltetrahydrophthalic anhydride, hexahydrophthalic anhydride Methylhexahydrophthalic anhydride, ethylhexahydrophthalic anhydride, itaconic anhydride, trimellitic anhydride, and the like.

  In the first reaction, a hydroxyl group is generated by an addition reaction between the epoxy group of the epoxy compound (a1) and the carboxyl group of the unsaturated monocarboxylic acid (a2). In the first reaction, the ratio of the epoxy compound (a1) to the unsaturated monocarboxylic acid (a2) is such that the unsaturated monocarboxylic acid (a2) is 0.001 equivalent to 1 equivalent of the epoxy group of the epoxy compound (a1). The ratio is preferably 7 to 1.05 equivalent, and more preferably 0.8 to 1.0 equivalent.

  The epoxy compound (a1) and the unsaturated monocarboxylic acid (a2) can be reacted by dissolving in an organic solvent. Examples of the organic solvent include ketones such as ethyl methyl ketone and cyclohexanone, aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene, methyl cellosolve, butyl cellosolve, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, Glycol ethers such as dipropylene glycol monoethyl ether, dipropylene glycol diethyl ether and triethylene glycol monoethyl ether, esters such as ethyl acetate, butyl acetate, butyl cellosolve acetate and carbitol acetate, aliphatic carbonization such as octane and decane Petroleum solvents such as hydrogen, petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha can be used.

  In the first reaction, it is preferable to use a catalyst in order to accelerate the reaction. Examples of the catalyst that can be used include triethylamine, benzylmethylamine, methyltriethylammonium chloride, benzyltrimethylammonium chloride, benzyltrimethylammonium bromide, benzyltrimethylammonium iodide, and triphenylphosphine. It is preferable that the usage-amount of a catalyst shall be 0.1-10 mass parts with respect to a total of 100 mass parts of an epoxy compound (a1) and unsaturated monocarboxylic acid (a2).

  In the first reaction, in order to prevent polymerization between the epoxy compounds (a1) or between the unsaturated monocarboxylic acids (a2) or between the epoxy compound (a1) and the unsaturated monocarboxylic acid (a2), a polymerization inhibitor is used. It is preferable to use it. As the polymerization inhibitor, for example, hydroquinone, methyl hydroquinone, hydroquinone monomethyl ether, catechol, pyrogallol and the like can be used. It is preferable that the usage-amount of a polymerization inhibitor shall be 0.01-1 mass part with respect to a total of 100 mass parts of an epoxy compound (a1) and unsaturated monocarboxylic acid (a2). 60-150 degreeC is preferable and, as for the reaction temperature of a 1st reaction, 80-120 degreeC is more preferable.

  In the first reaction, an unsaturated monocarboxylic acid (a2) and a polybasic acid anhydride such as trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, biphenyltetracarboxylic anhydride, etc., if necessary Can be used in combination.

  In the second reaction, when the hydroxyl group formed in the first reaction and the hydroxyl group originally present in the epoxy compound (a1) undergo a half-ester reaction with the acid anhydride group of the saturated or unsaturated polybasic acid anhydride (a3). Inferred. Here, 0.1 to 1.0 equivalent of polybasic acid anhydride (a3) can be reacted with 1 equivalent of hydroxyl group in the resin obtained by the first reaction. By adjusting the amount of the polybasic acid anhydride (a3) within this range, the acid value of the component (a) can be adjusted.

  Examples of the resin having an ethylenically unsaturated group and a carboxyl group include CCR-1218H, CCR-1159H, CCR-1222H, PCR-1050, TCR-1335H, ZAR-1035, ZAR-2001H, ZFR-1185, and ZCR- 1569H (Nippon Kayaku Co., Ltd., trade name) etc. are commercially available.

  The resin having a carboxyl group and an ethylenically unsaturated group as component (a) of the present invention is an epoxy acrylate compound having an ethylenically unsaturated group and two or more hydroxyl groups (hereinafter referred to as “raw material epoxy acrylate”). It is preferable to use a polyurethane compound obtained by reacting a diisocyanate compound (hereinafter referred to as “raw material diisocyanate”) and a diol compound having a carboxyl group (hereinafter referred to as “raw material diol”).

  Examples of the raw material epoxy acrylate include compounds obtained by reacting (meth) acrylic acid with an epoxy compound such as a bisphenol A type epoxy compound, a bisphenol F type epoxy compound, a novolac type epoxy compound, or an epoxy compound having a fluorene skeleton. Can be mentioned.

  As said raw material diisocyanate, if it is a compound which has two isocyanate groups, it can apply without a restriction | limiting in particular. Such compounds include, for example, phenylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, tridenic diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, arylene sulfone. Examples include ether diisocyanate, allyl cyanide diisocyanate, N-acyl diisocyanate, trimethylhexamethylene diisocyanate, 1,3-bis (isocyanatemethyl) cyclohexane, and norbornane-diisocyanate methyl. These can be used individually by 1 type or in combination of 2 or more types.

  The raw material diol is a compound having two hydroxyl groups in the molecule and a carboxyl group. Examples of the hydroxyl group include alcoholic hydroxyl groups and phenolic hydroxyl groups. From the viewpoint of improving the developability of the photosensitive resin composition with an alkaline aqueous solution, the hydroxyl group is preferably an alcoholic hydroxyl group. Examples of such raw material diols include dimethylolpropionic acid and dimethylolbutanoic acid.

  As said polyurethane compound, the compound which has a structural unit represented by following General formula (3) is mentioned, for example.

Here, in General Formula (3), R ¹⁰ represents a hydrogen atom or a methyl group, R ¹⁷ represents a residue of a raw material epoxy acrylate, R ¹⁸ represents a residue of a raw material diisocyanate, and R ¹⁹ represents 1 carbon atom. Represents an alkyl group of ~ 5. In addition, a residue means the structure of the part remove | excluding the functional group used for the coupling | bonding from the raw material component. Specifically, as R ¹⁷ , for example, bis (4-oxyphenyl) -methane, 2,2-bis (4-oxyphenyl) -propane, 2,2-bis (4-oxyphenyl) -1, Examples thereof include bisphenol A-type skeletons such as 1,1,3,3,3-hexafluoropropane and bisphenol F-type skeletons, novolak skeletons, fluorene skeletons, and the like. Examples of R ¹⁸ include phenylene, tolylene, xylylene, tetramethylxylylene, and the like. Lene, diphenylmethylene, hexamethylene, trimethylhexamethylene, dicyclohexylmethylene, isophorone and the like. The alkyl group having 1 to 5 carbon atoms for R ^19, a methyl group, an ethyl group, a propyl group, a butyl group, an isobutyl group, a pentyl group, amyl group.

  A plurality of groups in general formula (3) may be the same or different. Moreover, when the terminal of the polyurethane compound is a hydroxyl group, the hydroxyl group may be treated with a saturated or unsaturated polybasic acid anhydride.

  Further, in the general formula (3), the structural unit derived from the raw material epoxy acrylate and the structural unit derived from the raw material diol are alternately polymerized via the structural unit derived from the raw material diisocyanate. However, a structure in which a structural unit derived from a raw material epoxy acrylate and a structural unit derived from a raw material diol are polymerized in a block manner via a structural unit derived from a raw material diisocyanate may be used.

As the component (a), among the compounds represented by the general formula (3), it is preferable that the hard segment part of the raw material epoxy acrylate which is one of the main skeletons of polyurethane, that is, R ¹⁷ has a bisphenol A structure. Such a compound is commercially available as UXE-3011, UXE-3012, UXE-3024 (manufactured by Nippon Kayaku Co., Ltd.) and the like. These can be used alone or in combination of two or more.

  The component (a) has an acid value of preferably 20 to 180 mgKOH / g, more preferably 30 to 150 mgKOH / g, and still more preferably 40 to 120 mgKOH / g. By making the said acid value into such a range, the developability of the photosensitive resin composition by alkaline aqueous solution can be improved, and the resolution can be improved.

  Here, the acid value can be measured by the following method. First, after precisely weighing about 1 g of the measurement resin solution, 30 g of acetone is added to the resin solution to uniformly dissolve the resin solution. Next, an appropriate amount of phenolphthalein as an indicator is added to the solution, and titration is performed using a 0.1N aqueous KOH solution. Then, the acid value is calculated by the following formula (α).

  A = 10 × Vf × 56.1 / (Wp × I) (α)

  In the formula (α), A represents the acid value (mgKOH / g), Vf represents the titration amount (mL) of KOH, Wp represents the measurement resin solution mass (g), and I represents the nonvolatile content of the measurement resin solution. The ratio (mass%) is shown.

  In addition, the weight average molecular weight of the component (a) is preferably 3000 to 30000, more preferably 5000 to 20000, and still more preferably 7000 to 15000 from the viewpoint of coating properties. These may be used alone or in combination of two or more resins having different molecular weights.

In addition, in this specification, a weight average molecular weight (Mw) means the value calculated | required from the standard polystyrene conversion value by gel permeation chromatography (GPC). The measurement conditions in GPC are as follows.
Model: Hitachi L6000
Detection: L3300RI
Column: Gelpack GL-R440 + GL-R450 + GL-R400M
Column specifications: Diameter 10.7mm x 300mm
Solvent: THF
Sample concentration: 120 mg of NV (non-volatile content) 40% by mass of resin solution was collected and dissolved in 5 mL of THF. Injection amount: 200 μL
Pressure: 49Kg · f / cm ²
Flow rate: 2.05 mL / min

<(B) component; photopolymerizable monomer having an ethylenically unsaturated group>
In the present invention, the component (b) can be used without any particular limitation, but for further improvement of HAST resistance, a photopolymerizable monomer having an ethylenically unsaturated group and a tricyclodecane structure or a bisphenol A-based (meth). It is preferable to contain an acrylate compound.

  Examples of bisphenol A-based (meth) acrylate compounds include 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane and 2,2-bis (4-((meth) acryloxypolypropoxy). ) Phenyl) propane, 2,2-bis (4-((meth) acryloxypolybutoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypolyethoxypolypropoxy) phenyl) propane, etc. Can be mentioned.

  Examples of 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane include 2,2-bis (4-((meth) acryloxydiethoxy) phenyl) propane, 2,2- And bis (4-((meth) acryloxypentaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypentadecaethoxy) phenyl) and the like, and 2,2-bis (4- (Methacryloxypentaethoxy) phenyl) propane is commercially available as BPE-500 (product name, Shin-Nakamura Chemical Co., Ltd.) and FA-321M (product name, Hitachi Chemical Co., Ltd.). , 2-bis (4- (methacryloxypentadecaethoxy) phenyl) is commercially available as BPE-1300 (trade name, manufactured by Shin-Nakamura Chemical Co., Ltd.). That. These can be used alone or in combination of two or more.

  In the present invention, the component (b) preferably contains a photopolymerizable monomer having an ethylenically unsaturated group and a tricyclodecane structure.

  The photopolymerizable monomer having an ethylenically unsaturated group and a tricyclodecane structure is not particularly limited as long as it is a photopolymerizable monomer having a tricyclodecane structure. For example, dimethylol tricyclodecane diacrylate, dimethylol , Tricyclodecane dimethacrylate, tricyclodecane diol diacrylate, and tricyclodecane diol dimethacrylate are preferable. Compounds corresponding to these are available as NK ester DCP and NK ester A-DCP (both manufactured by Shin-Nakamura Chemical Co., Ltd.).

  The photopolymerizable monomer having an ethylenically unsaturated group and a tricyclodecane structure preferably has a partial structure represented by the following general formula (1) or the following general formula (2).

［一般式（１）及び一般式（２）中、Ｒ^１、Ｒ^２は、直接結合、アルキレン、又はアリーレン基を示す。］

[In General Formula (1) and General Formula (2), R ¹ and R ² represent a direct bond, an alkylene, or an arylene group. ]

  The alkylene group is preferably an alkylene group having 2 to 20 carbon atoms, more preferably an alkylene group having 2 to 10 carbon atoms, and further preferably an alkylene group having 2 to 6 carbon atoms.

  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. From the viewpoint of resolution and plating resistance, an ethylene group or an isopropylene group. It is preferred that it is ethylene group.

  The arylene group is preferably an arylene group having 6 to 14 carbon atoms, and more preferably an arylene group having 6 to 10 carbon atoms. Examples of such an arylene group include phenylene and naphthylene.

  When the compound having the partial structure represented by the general formula (1) or the general formula (2) is used as the component (b), (b1) a diol compound containing a tricyclodecane structure and (b2) diisocyanate A urethane compound obtained by reacting a compound with (b3) a compound having at least one ethylenically unsaturated group and one hydroxyl group in the molecule is preferable.

  Although there is no restriction | limiting in particular as said (b2) diisocyanate, The compound which has a ring structure is preferable. Among these, those having a rigid structure such as isophorone diisocyanate are more preferable from the viewpoint of crack resistance (heat resistance).

  In addition, the compound (b3) having at least one ethylenically unsaturated group and one hydroxyl group in the molecule has two ethylenically unsaturated groups from the viewpoint of crosslinking density. Those having three are particularly preferred.

  Among these, the diisocyanate is isophorone diisocyanate, and in addition, a compound having at least one ethylenically unsaturated group and one hydroxyl group in the molecule is represented by the general formula (2). Is more preferable. Examples of such a compound include UX-5002D-M20 (manufactured by Nippon Kayaku Co., Ltd.). These can be used alone or in combination of two or more.

  The component (b) is a combination of a compound having no urethane bond in the molecule and a compound having a urethane bond in the molecule, which improves various properties required for the solder resist. Then, it is preferable.

  As other component (b), a compound obtained by reacting a polyhydric alcohol with an α, β-unsaturated carboxylic acid; a compound obtained by reacting a glycidyl group-containing compound with an α, β-unsaturated carboxylic acid; Examples thereof include urethane monomers or urethane oligomers such as (meth) acrylate compounds having a urethane bond in the molecule. Besides these, nonylphenoxypolyoxyethylene acrylate; γ-chloro-β-hydroxypropyl-β ′-(meth) Phthalic acid compounds such as acryloyloxyethyl-o-phthalate and β-hydroxyalkyl-β ′-(meth) acryloyloxyalkyl-o-phthalate; (meth) acrylic acid alkyl ester, ethylene oxide modified nonylphenyl (meth) acrylate Etc. can be exemplified. These may be used alone or in combination of two or more.

<(C) Component: Photopolymerization initiator>
The (c) photopolymerization initiator used in the present invention is not particularly limited as long as it matches the light wavelength of the exposure machine to be used, and known ones can be used. Specifically, for example, benzophenone, N, N′-tetraalkyl-4,4′-diaminobenzophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, 2-methyl- 1- (4-methylthiophenyl] -2-morpholinopropan-1-one, 4,4′-bis (dimethylamino) benzophenone (Michler ketone), 4,4′-bis (diethylamino) benzophenone, 4-methoxy-4 Aromatic ketones such as'-dimethylaminobenzophenone; benzyl derivatives such as benzyldimethyl ketal; 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4,5-di (M-methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-diphe Nilimidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2,4-di (p-methoxyphenyl) -5-phenylimidazole dimer, 2- (2, 2,4,5-triarylimidazole dimers such as 4-dimethoxyphenyl) -4,5-diphenylimidazole dimer; acridine derivatives such as N-phenylglycine, N-phenylglycine derivatives, 9-phenylacridine; Oxime ester compounds such as 1,2-octanedione and 1- [4- (phenylthio)-, 2- (o-benzoyloxime)]; Coumarin compounds such as 7-diethylamino-4-methylcoumarin; 2,4-diethyl Thioxanthone compounds such as thioxanthone; 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide Acylphosphine oxide compounds and the like. These may be used alone or in combinations of two or more.

  Among these, it is preferable to use an aromatic ketone, and it is more preferable to use 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one. Moreover, (c) When using an aromatic ketone as a photoinitiator, it is preferable that a thioxanthone compound is included as a sensitizer. Thereby, an opening shape can be made more favorable.

  Examples of the thioxanthone compound include 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, and 2,4-diisopropylthioxanthone. Among these, it is more preferable to contain 2,4-diethylthioxanthone. 2,4-Diethylthioxanthone is commercially available as KAYACURE-DETX (manufactured by Nippon Kayaku Co., Ltd., product name).

  Moreover, it is also preferable to use a phosphine oxide compound from the viewpoint of improving the resist shape. Examples of such compounds include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (2,6-dimethoxybenzoyl)- 2,4,4-trimethyl-pentylphosphine oxide is mentioned. These are commercially available as DAROCURE-TPO and IRGACURE-819 (both manufactured by Ciba Japan Co., Ltd., trade names).

  Moreover, when using a phosphine oxide compound as (c) photoinitiator, it is preferable to further contain the compound which has oxime ester for the purpose of a sensitivity improvement. Examples of the compound having the oxime ester include (2- (acetyloxyiminomethyl) thioxanthen-9-one), (1,2-octanedione, 1- [4- (phenylthio)-, 2- (o -Benzoyloxime)], ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (o-acetyloxime)). Examples of commercially available products include IRGACURE-OXE01 and IRGACURE-OXE02 (both manufactured by Ciba Specialty Chemicals).

<(D) component: epoxy resin with chlorine content of 500 ppm or less>
As the epoxy resin in which the chlorine content of the component (d) used in the present invention is 500 ppm or less, a high-purity epoxy resin that satisfies the above chlorine content is used. In general, epoxy resins are obtained by reacting epichlorohydrin, but the chlorine and hydrolyzable chlorine generated as impurities during the reaction are removed by molecular distillation, etc., and their content is low. is there.

  To reduce the chlorine content, (1) 1,2-propylene chlorohydrin, (2) 1,3-propylene chlorohydrin as a side reaction, (3) before (1) is epoxidized As a method of dehydrochlorinating an unreacted substance such as chloromethylation reacted with epichlorohydrin to an epoxy group by dehydrochlorination with an alkali hydroxide or the like, it is dissolved in a solvent such as toluene or methyl isobutyl ketone, and then sodium hydroxide, hydroxide The reaction can be carried out by adding an aqueous solution of an alkali metal hydroxide such as potassium to ensure ring closure. In this case, the amount of the alkali metal hydroxide used is usually 0.01 to 0.3 mol, preferably 0.05 to 0.2 mol, relative to 1 mol of the hydroxyl group of the phenolic resin used for epoxidation. The reaction temperature is usually 50 to 120 ° C., and the reaction time is usually 0.5 to 2 hours. After completion of the reaction, the formed salt is removed by filtration, washing with water, etc., and the solvent is further distilled off under heating and reduced pressure. In addition, the epoxy resin can be obtained by molecular distillation.

  Examples of commercially available epoxy resins include YD-8125, YDF-8170C, ZX-1059, YD-825GS, YDF-870GS, ZX-1658, and ZX-1627 (product names), which are purified by molecular distillation. , Manufactured by Toto Kasei Co., Ltd.), YX-8000, YX-8034 (product name, manufactured by Japan Epoxy Resin Co., Ltd.), N-655EXP-S, N-665EXP, N-670EXP-S, N-672EXP, N-685EXP -S, (product name, manufactured by DIC Corporation), R140P, R140S, R140Q (product name, manufactured by Mitsui Chemicals), ED-509S, ED-518S (manufactured by ADEKA Corporation), NC-3000H (product name, Nippon Kayaku Co., Ltd.).

  The epoxy resin used in the present invention is not limited to the above as long as it has a high purity. Moreover, it is desirable to use the epoxy resin which is solid at room temperature (25 ° C.) and has a softening point of 30 ° C. to 100 ° C., more preferably a softening point of 50 ° C. to 100 ° C. Furthermore, it is preferable to use a bisphenol F type epoxy resin from the viewpoint of various reliability.

  The content of each component in the photosensitive resin composition is 30 to 80 parts by weight of component (a) and 20 to 70 parts by weight of component (b) with respect to 100 parts by weight of the total of components (a) and (b). It is preferable to become a part. Furthermore, it is more preferable that the component (a) is blended in an amount of 40 to 75 parts by weight and the component (b) in an amount of 25 to 60 parts by weight. In addition, the component (c) is blended in an amount of 0.1 to 30 parts by weight, preferably 0.1 to 20 parts by weight, and more preferably 0.1 to 10 parts by weight. The component (d) is preferably 3 to 50 parts by weight, and more preferably 5 to 40 parts by weight. If the amount is too large, the HAST resistance may deteriorate due to the residual epoxy component, and if the amount is too small, sufficient cured film characteristics may not be obtained.

  In addition to the above-described components (a) to (d), the photosensitive resin composition used in the present invention may further include other components according to desired characteristics.

  Other components include the epoxy resin curing accelerator (e) of component (e), but there is no particular limitation. For example, dicyandiamide, benzyldimethylamine, 4- (dimethylamino) -N, N-dimethylbenzylamine Amine compounds such as 4-methoxy-N, N-dimethylbenzylamine and 4-methyl-N, N-dimethylbenzylamine; quaternary ammonium salt compounds such as triethylbenzylammonium chloride; blocked isocyanate compounds such as dimethylamine; imidazole 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, 1- (2-cyanoethyl) -2-ethyl -4-methyli Imidazole derivative bicyclic amidine compounds such as dazole and salts thereof; phosphorus compounds such as triphenylphosphine; guanamine compounds such as melamine, guanamine, acetoguanamine and benzoguanamine; 2,4-diamino-6-methacryloyloxyethyl-s-triazine 2-vinyl-2,4-diamino-s-triazine, 2-vinyl-4,6-diamino-s-triazine isocyanuric acid adduct, 2,4-diamino-6-methacryloyloxyethyl-s-triazine, S-triazine derivatives such as isocyanuric acid adducts, boron trifluoride-amine complexes, organic hydrazides, phthalic anhydride, trimellitic anhydride, ethylene glycol bis (anhydrotrimellitic acid), glycerol tris (anhydrotrimellitic acid) Tate , Aromatic acid anhydrides such as benzophenone tetracarboxylic anhydride, aliphatic acid anhydrides such as maleic anhydride and tetrahydrophthalic anhydride, polyphenols such as polyvinylphenol, polyvinylphenol bromide, phenol novolac, alkylphenol novolac, etc. Can be used.

  Among these, dicyandiamide, imidazole, 2-methylimidazole, 2-ethylimidazole, 2-vinyl-4,6-diamino-s-triazine / isocyanuric acid adduct and the like are preferable. These may be used alone or in combination of two or more. As a usage-amount, it is preferable to be used at 0.1-10 mass% with respect to 100 mass parts of total amounts of (a) component and (b) component.

  The photosensitive resin composition of the present invention is a melamine, dicyandiamide, triazine compound and derivatives thereof, imidazole, thiazole, triazole, silane as adhesion improvers, particularly when adhesion with metals such as copper is required. Additives such as coupling agents can be used. For example, melamine, acetoguanamine, benzoguanamine, melamine-phenol-formalin resin, dicyandiamide, manufactured by Shikoku Kasei Kogyo Co., Ltd .; 2MZ-AZINE (2,4-diamino-6- [2'-methylimidazolyl- (1 ')]- Ethyl-s-triazine), 2E4MZ-AZINE (2,4-diamino-6- [2′-ethyl-4′-methylimidazolyl- (1 ′)]-ethyl-s-triazine), C11Z-AZINE (2, 4-diamino-6- [2'-undecylimidazolyl- (1 ')]-ethyl-s-triazine), 2MA-OK (2,4-diamino-6- [2'-methylimidazolyl- (1')) ] -Ethyl-s-triazine isocyanuric acid adduct). Alternatively, triazine derivatives such as ethyldiamino-s-triazine, 2,4-diamino-s-triazine, and 2,4-diamino-6-xylyl-s-triazine are exemplified. These compounds increase adhesion with a copper circuit and improve PCT resistance, and are also effective in HAST resistance. These are preferably used in an amount of 0.1 to 10% by mass based on 100 parts by mass of the total amount of the component (a) and the component (b).

  Among these, it is preferable that melamine or dicyandiamide is included, and it is more preferable that both melamine or dicyandiamide are included.

  Moreover, in this invention, it is preferable to use an inorganic filler as needed in order to improve characteristics, such as adhesiveness and hardness. Examples of inorganic fillers include inorganic fillers such as barium sulfate, barium titanate, powdered silicon oxide, amorphous silica, talc, clay, calcined kaolin, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, and mica powder. Can be used. The amount used is preferably 0 to 70% by mass with respect to the solid content of the photosensitive resin composition.

  In the present invention, it is desirable to use a diluting solvent as necessary. Examples of the diluent include aliphatic alcohols such as methanol, ethanol, n-propanol, i-propanol, n-butanol, n-pentanol and hexanol; hydrocarbons such as benzyl alcohol and cyclohexane; diacetone alcohol; Aliphatic ketones such as 3-methoxy-1-butanol, acetone, methyl ethyl ketone, methyl propyl ketone, diethyl ketone, methyl isobutyl ketone, methyl pentyl ketone, methyl hexyl ketone, ethyl butyl ketone, dibutyl ketone; ethylene glycol, diethylene glycol, tri Ethylene glycol, tetraethylene glycol, propylene glycol, ethylene glycol monoacetate, ethylene glycol diacetate, propylene glycol monoacetate, pro Ethylene glycol alkyl ethers such as lenglycol diacetate, propylene glycol monoethyl ether, methyl cellosolve, ethyl cellosolve, butyl cellosolve, phenyl cellosolve, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, methyl cellosolve acetate, ethyl cellosolve acetate And its acetate, diethylene glycol monoalkyl ether and its acetate, diethylene glycol dialkyl ether, triethylene glycol alkyl ether, propylene glycol alkyl ether and its acetate, dipropylene glycol alkyl ether, toluene, petroleum ether, petroleum naphtha , Hydrogenated oil naphtho Or petroleum solvents such as solvent naphtha, carboxylic acids such as ethyl formate, propyl formate, butyl formate, amyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, methyl butyrate, ethyl butyrate Esters, amines, amides such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, dioxane, tetrahydrofuran, cyclohexanone, γ-butyrolactone, 3-hydroxy Solvents such as 2-butanone, 4-hydroxy-2-pentanone, and 6-hydroxy-2-hexanone can be used alone or in combination of two or more.

  If necessary, use colorants such as phthalocyanine blue, phthalocyanine green, iodine green, disazo yellow, malachite green, crystal violet, titanium oxide, carbon black, naphthalene black, azo organic pigments, dyes, etc. it can. Furthermore, polymerization inhibitors such as hydroquinone, hydroquinone monomethyl ether, tert-butylcatechol, pyrogallol and phenothiazine, thixotropic agents such as benton, montmorillonite, aerosil and amide wax, antifoaming agents such as silicone, fluorine and polymer Leveling agents can be used.

  When the diluent used in the present invention is applied to a support and used as a photosensitive film, it is preferably contained in an amount of 20 to 70% of the total mass in a varnish state before coating. Then, since it will volatilize in the drying process at the time of film preparation after setting it as a film, it is preferable to make it become a solvent content of 2 mass% or less.

Next, the photosensitive film will be described.
The photosensitive film obtained by using the photosensitive resin composition of the present invention comprises a support and a photosensitive resin composition layer comprising the photosensitive resin composition of the present invention formed on the support. It is. On the photosensitive resin composition layer, you may further provide the protective film which coat | covers this photosensitive resin composition layer.

  The photosensitive resin composition layer is prepared by dissolving the photosensitive resin composition of the present invention in the above solvent or mixed solvent to obtain a solution having a solid content of about 30 to 80% by mass, and then applying the solution onto a support. It is preferable to form. Although the thickness of the photosensitive resin composition layer varies depending on the use, it is preferably 5 to 200 μm and more preferably 15 to 60 μm in thickness after drying after removing the solvent by heating and / or hot air blowing. . If this thickness is less than 5 μm, it tends to be difficult to apply industrially, and if it exceeds 200 μm, the above-mentioned effects produced by the present invention tend to be reduced, and in particular, physical properties and resolution tend to decrease.

  Examples of the support provided in the photosensitive film include polymer films having heat resistance and solvent resistance such as polyethylene terephthalate, polypropylene, polyethylene, and polyester.

  The thickness of the support is preferably 5 to 100 μm, and more preferably 10 to 30 μm. If the thickness is less than 5 μm, the support tends to be broken when the support is peeled off before development, and if it exceeds 100 μm, the resolution and flexibility tend to decrease.

  The photosensitive film consisting of two layers of the support and the photosensitive resin composition layer as described above or the photosensitive film consisting of three layers of the support, the photosensitive resin composition layer, and the protective film, for example, is stored as it is. Alternatively, the protective film may be interposed and wound around the core in a roll shape and stored.

  In the resist pattern forming method using the photosensitive resin composition or photosensitive film of the present invention, first, a resist is formed by a known screen printing, a step of applying by a roll coater, or a step of applying by lamination or the like. A photosensitive resin composition is laminated on the substrate. Then, if necessary, the support is removed from the above-described photosensitive film (generally, the support is provided without being removed, and is peeled off before the development step), and actinic rays are passed through the mask pattern. Then, an exposure step of irradiating a predetermined portion of the photosensitive resin composition layer and photocuring the photosensitive resin composition layer of the irradiated portion is performed. The photosensitive resin composition layer other than the irradiated part is removed by the next development step. In addition, the board | substrate which forms a resist points out a printed wiring board, a board | substrate for semiconductor packages, and a flexible wiring board.

  As the light source of actinic light, a known light source such as a carbon arc lamp, a mercury vapor arc lamp, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, or a xenon lamp that emits ultraviolet rays effectively is used. Moreover, what emits visible light effectively, such as a photographic flood light bulb and a solar lamp, is also used. Further, direct drawing direct laser exposure may be used. By using the component (c) corresponding to each laser light source and exposure method, it is possible to form an excellent pattern.

  In the development step, an alkaline developer such as a dilute solution of sodium carbonate (0.1 to 10% by mass aqueous solution, preferably 1 to 5% by mass aqueous solution) at 20 to 50 ° C. is used as the developer. Development is performed by a known method such as rocking immersion, brushing or scraping.

  As the alkali developer, for example, an aqueous alkali solution such as sodium hydroxide, potassium hydroxide, sodium silicate, ammonia, ethylamine, diethylamine, triethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH) is preferably used. The base concentration of these aqueous solutions is preferably 0.1 to 10% by mass. Furthermore, alcohols and surfactants can be added to the developer and used. Each of these can be blended in the range of preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the developer.

In the above development step, the photosensitive layer that has been hardened by irradiation with actinic rays is left, and the photosensitive layer other than the predetermined portion is removed, and the photosensitive layer is treated with an aqueous solution containing divalent metal ions. The divalent metal ions include Ca ²⁺ , Mg ²⁺ , Sr ²⁺ , Ba ²⁺ , Cd ²⁺ , Ni ²⁺ , Zn ²⁺ , Cu ²⁺ , Hg ²⁺ , Fe ²⁺ , Co ²⁺ , Sn ²⁺ , Pb ²⁺ , Mn ^2+, etc. And is preferably at least one metal ion selected from Ca ²⁺ , Mg ²⁺ , Sr ²⁺ and Ba ²⁺ . Ca ²⁺ and Mg ²⁺ are preferable because the moisture resistance insulation on the surface of the permanent mask resist is improved and the material is easily available. The divalent metal ions are prepared by dissolving and dispersing compounds such as sulfates, nitrates, chloride salts, acetates, carbonates, oxalates, phosphates and hydroxides containing divalent metal ions in water. Are preferably used. If the basicity is strong, the photosensitive layer dissolves or peels off. Therefore, weak basicity is preferable. Sulfates, nitrates, chlorides, acetates, carbonates, oxalates, phosphates, etc. From the viewpoint of properties, nitrates and acetates are preferred.

  The metal ion concentration in the aqueous solution containing divalent metal ions is preferably 1 to 2000 ppm, more preferably 50 to 500 ppm, further preferably 50 to 500 ppm, and more preferably 50 to 350 ppm. Particularly preferred.

  During the development process, monovalent sodium ions and potassium ions contained in the developer are incorporated into the solder resist surface layer, and the incorporated monovalent cations form a 1: 1 ionic bond with the carboxylic acid. It is thought that there is. By substituting the monovalent cation with a divalent metal ion, the divalent metal ion can form a 1: 2 ionic bond with the carboxylic acid. Then, it seems that crosslinking of the solder resist surface apparently improves and HAST resistance improves. As described above, the HAST resistance can be improved by processing with an aqueous solution containing a divalent metal ion after development.

  The treatment with an aqueous solution containing divalent metal ions involves contacting the photosensitive resin composition layer that has been developed and formed a pattern with an aqueous solution containing divalent metal ions, and spraying the aqueous solution or in the aqueous solution. It is to make the photosensitive resin composition layer in which the divalent metal ion and the pattern were formed contact with each other. It is considered that the metal ions adsorbed on the surface of the photosensitive resin composition layer are diffused to some extent and are captured by the carboxylic acid in the composition as described above. The treatment temperature and time are 20-60 ° C., 5 seconds to 1 day, and the contact temperature, aqueous solution concentration and contact time can be adjusted to adjust the concentration of metal ions that can be taken in. The treatment temperature is high and the aqueous solution concentration is high. The longer the contact time, the higher the concentration of metal ions taken in.

  For example, 1 g of the permanent mask resist on the substrate is scraped off and placed in a tetrafluoroethylene container together with 30 cc of pure water having an electric conductivity of 18 MΩ or more, and the metal ions thus taken are 4 to 8 hours at 100 to 120 ° C. After heat treatment, the ionic component is thermally extracted, and then the extracted sample is returned to room temperature (25 ° C.), ion chromatography (manufactured by DIONEX, model DXIon Chromatograph, etc.), atomic absorption photometer (manufactured by Hitachi, Ltd.) , Model Z5010 etc.) can be used to quantify the metal cation component and concentration in the permanent mask resist. Moreover, the quantity of the metal cation substituted by the process can be calculated by quantifying the concentration of the metal cation contained in the treated aqueous solution by ion chromatography.

After the development step and the treatment with the aqueous solution containing divalent metal ions, ultraviolet irradiation or heating with a high-pressure mercury lamp or the like is preferably performed for the purpose of improving solder heat resistance, chemical resistance and the like. When irradiating with ultraviolet rays, the irradiation amount can be adjusted as necessary. For example, the irradiation can be performed at an irradiation amount of about 0.2 to 10 J / cm ² . Moreover, when heating a resist pattern, it is preferable to carry out for 15 to 90 minutes in the range of about 100-170 degreeC. Furthermore, ultraviolet irradiation and heating can be performed at the same time, and after either one is performed, the other can be performed. When performing ultraviolet irradiation and heating simultaneously, it is more preferable to heat to 60 to 150 ° C. from the viewpoint of effectively imparting solder heat resistance, chemical resistance and the like.

  After completion of the development step, washing with water, and performing the above-described ultraviolet irradiation and heating, treatment with an aqueous solution containing a divalent metal ion can also be performed. Further, the treatment with an aqueous solution containing a divalent metal ion can be carried out again after the development step and after ultraviolet irradiation or heating. If necessary, washing and decomposition can be performed to remove excess metal ions adhering to the surface of the photosensitive resin composition layer after the treatment.

  This photosensitive resin composition layer also serves as a protective film for wiring after soldering to the substrate, has good lamination temperature stability, excellent resolution, excellent flatness, crack resistance, HAST resistance, Since it has gold plating properties, it is effective as a solder resist for printed wiring boards, semiconductor package substrates, and flexible wiring boards.

  The substrate provided with the resist pattern in this manner is then mounted with a semiconductor element or the like (for example, wire bonding or solder connection) and then mounted on an electronic device such as a personal computer.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

(Preparation of photosensitive resin composition solution)
First, the photosensitive resin composition solution was obtained by mixing each component shown in Table 1 by the compounding quantity (mass part) shown in the same table. The following components were used for each component shown in Table 1.

<(A) component (resin having an ethylenically unsaturated group and a carboxyl group)>
“UXE-3024 (weight average molecular weight; 10,000)”: urethane-modified epoxy acrylate (manufactured by Nippon Kayaku Co., Ltd.).
“UE-EXP-2810PM (weight average molecular weight; 10,000)”: acid-modified cresol novolac epoxy acrylate (manufactured by DIC Corporation).

<(B) component (photopolymerizable monomer having an ethylenically unsaturated group)>
“FA-321M”: 2,2-bis (4- (methacryloxypentaethoxy) phenyl) propane (manufactured by Hitachi Chemical Co., Ltd.).
“NK Espel DCP”: Tricyclodecane dimethanol dimethacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.).
"UX-5002D-M20": Tricyclodecane structure-containing urethane acrylate (manufactured by Nippon Kayaku Co., Ltd.).

<(C) component (photopolymerization initiator)>
“DAROCURE-TPO”: bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (manufactured by Ciba Specialty Chemicals).
“IRGACURE-OXE02”: Etanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (O-acetyloxime) (Ciba Specialty Chemicals) ).
“IRGACURE-907”: 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one (manufactured by Ciba Specialty Chemicals).
“KATACURE-DETX-S”: 2,4-diethylthioxanthone (product name) manufactured by Nippon Kayaku Co., Ltd.

<(D) component (epoxy resin)>
“NC-3000H”: molecularly distilled product, bisphenol F type epoxy resin (total chlorine amount 450 ppm, manufactured by Nippon Kayaku Co., Ltd., trade name).
“YD825GS”: molecularly distilled product, bisphenol A type epoxy resin (total chlorine amount 200 ppm, manufactured by Tohto Kasei Co., Ltd., trade name).
“YX4000H”: biphenyl type epoxy resin (total chlorine amount 1180 ppm, manufactured by Japan Epoxy Resin Co., Ltd., trade name).
“Epicoat 825”: bisphenol A type epoxy resin (standard product, total chlorine amount 1880 ppm, manufactured by Japan Epoxy Resin Co., Ltd., trade name).

<Other ingredients>
“Fine melamine”: Melamine (trade name, manufactured by Nissan Chemical Industries, Ltd.).
“Dicyandiamide”: “Epicure DICY7” (trade name, manufactured by Japan Epoxy Resin Co., Ltd.).
“Esper 1108”: polyester elastomer (trade name, manufactured by Hitachi Chemical Co., Ltd.).
“Phthalocyanine blue”: (trade name, manufactured by Toyo Ink Co., Ltd.).
“Variace B-30”: A barium sulfate dispersion prepared by the following method using barium sulfate “Variace B-30” (trade name, manufactured by Sakai Chemical Industry Co., Ltd.).

  (B) 20 parts by mass (solid content) of the component, 25 parts by mass of the barium sulfate, and 40 parts by mass of methyl ethyl ketone were mixed with Starmill LMZ (manufactured by Ashizawa Finetech Co., Ltd.) using zirconia beads having a diameter of 1.0 mm. Dispersion was carried out at 12 m / s for 3 hours to obtain a barium sulfate dispersion. Barium sulfate was added to the photosensitive resin composition by blending the dispersion prepared above.

  In the photosensitive resin composition solutions of Examples and Comparative Examples, a mixed solution of methyl ethyl ketone and N, N-dimethylformamide as a diluent at a mass ratio of 1: 1 is used, and the solid content of the resin composition solution is 60% by mass. It was added to become.

  <Preparation of aqueous solution>

Ca ²⁺ was selected as the divalent metal ion. Calcium acetate ((CH ₃ COO) ₂ Ca) 1.184 g in 1 liter of ion-exchanged water using calcium acetate (molecular weight = 158.14 (anhydrous), containing 25.34% by mass of calcium) as a supply source Was dissolved to prepare an aqueous solution containing 300 ppm of calcium ions.

In addition, ion-exchanged water containing no calcium ions was prepared.
[1.184 × 0.2534 / 1000 = 0.0003 (300 ppm)]

(Preparation of photosensitive film)
Next, the photosensitive resin composition solution obtained above is uniformly coated on a 16 μm-thick polyethylene terephthalate film (G2-16, trade name, manufactured by Teijin Ltd.) as a support, thereby forming the photosensitive resin composition. A material layer was formed and dried for about 10 minutes at 100 ° C. using a hot air convection dryer. The film thickness after drying of the photosensitive resin composition layer was 25 μm.

  Subsequently, on the surface of the photosensitive resin composition layer opposite to the side in contact with the support, a polyethylene film (NF-15, manufactured by Tamapoly Co., Ltd., trade name) is bonded as a protective film, and is photosensitive. A film (photosensitive element) was obtained.

(Characteristic evaluation of photosensitive film)
Each of the following tests was performed using the photosensitive films of Examples 1 to 5 and Comparative Examples 1 to 4, respectively, and resolution, opening shape, gold plating resistance, solder heat resistance when each photosensitive element was used. The HAST resistance was evaluated. The obtained results are shown in Table 2.

(Resolution evaluation)
The copper surface of a printed wiring board substrate (MCL E-679, manufactured by Hitachi Chemical Co., Ltd., trade name) obtained by laminating a 12 μm thick copper foil on a glass epoxy substrate was polished with an abrasive brush, washed with water, and then dried. . The polyethylene film of the photosensitive film is peeled off on this printed wiring board substrate, and a vacuum pressure laminator (2-stage system with flat press, MVLP-500, product name, manufactured by Meiki Seisakusho Co., Ltd.) is used. Lamination was performed under the conditions of pressure bonding pressure 0.4 MPa, press hot plate temperature 80 ° C., evacuation time 20 seconds, laminate press time 30 seconds, and atmospheric pressure 4 kPa or less to obtain a laminate for evaluation.

  A photo tool having a via diameter pattern with a diameter of 10 μm in a range of 30 to 100 μm in diameter as a negative is closely adhered on the evaluation laminate, and an EXM-1201 type exposure machine manufactured by Oak Manufacturing Co., Ltd. The exposure was performed with an energy amount such that the number of remaining steps after development of 16.0 was 16.0. Next, after standing at room temperature (25 ° C.) for 1 hour, the polyethylene terephthalate on the laminate was peeled off and spray-developed with a 1% by mass aqueous sodium carbonate solution at 30 ° C. for 60 seconds, followed by a water washing step (ion Exchange water or Ca ion aqueous solution and spray water washing for 120 seconds) were performed to form a resist pattern.

  The formed resist pattern was observed with a stereomicroscope, the minimum opening via diameter was measured, and the resolution was obtained. The smaller the value, the better the resolution. The evaluation results are shown in Table 2.

(Evaluation of opening shape)
Using the substrate on which the resolution was evaluated, the cross-sectional shape of the formed resist pattern was observed and evaluated according to the following criteria. The evaluation results are shown in Table 2.
“A”: Solder resist hem or float cannot be observed at the bottom of the opening.
“B”: The bottom can be observed at the bottom of the opening.
“C”: A solder resist float can be observed at the bottom of the opening.

(Evaluation of electroless Ni / Au plating resistance)
In the same manner as the evaluation laminate used for the above-described resolution evaluation, a plating resistance evaluation substrate was produced. However, using a photo tool having a via pattern with a diameter of 200 μm as a negative, the obtained resist pattern was irradiated with ultraviolet rays at an energy amount of 1 J / cm ² using an ultraviolet irradiation device manufactured by Oak Manufacturing Co., Ltd., and further 160 An evaluation laminate substrate on which a solder resist having a via opening with a diameter of 200 μm was formed was obtained in the same manner except that heat treatment was performed at 60 ° C. for 60 minutes. By heating at this time, calcium acetate adhering to the surface is decomposed into acetone and calcium carbonate.

  The laminated substrate for evaluation obtained above is subjected to electroless nickel plating (trade name Nimden NPR-4, manufactured by Uemura Kogyo Co., Ltd.) (15 minutes treatment), and further electroless gold plating (manufactured by Uemura Kogyo Co., Ltd.). The product name Orical TKK-511) was applied (15 minutes treatment).

For the evaluation substrate thus plated, the plating solution soaked into the bottom of the solder resist, and the solder resist floating and peeling from the substrate were observed with a 100-fold metal microscope, and the following criteria Thus, the electroless Ni / Au plating resistance was evaluated. The evaluation results are shown in Table 2.
“A”: No penetration into the solder resist bottom.
“B”: A penetration of 1 to 10 μm into the bottom of the solder resist.
“C”: other than above.

(Evaluation of solder heat resistance)
In the same manner as the evaluation laminate used for the above-described resolution evaluation, a solder heat resistance evaluation board was produced. However, using a photo tool having a 2 mm square lattice pattern as a negative, the obtained resist pattern was irradiated with ultraviolet rays at an energy amount of 1 J / cm ² using an ultraviolet irradiation device manufactured by Oak Manufacturing Co., Ltd., and further 160 A laminated substrate for evaluation in which a solder resist having a 2 mm square lattice pattern was formed was obtained in the same manner except that the heat treatment was carried out at 60 ° C. for 60 minutes.

  Next, after applying rosin-based flux (MH-820V, manufactured by Tamura Kaken Co., Ltd., trade name) to the evaluation laminate substrate obtained above, the solder treatment is performed by immersing in a solder bath at 260 ° C. for 30 seconds. went.

In this way, the state of solder resist cracking on the evaluation substrate that was solder-plated on the copper surface that was not covered with the resist was observed visually, and the degree of peeling of the solder resist from the substrate and the degree of peeling were visually observed. The solder heat resistance of the solder resist was evaluated based on the above criteria. The evaluation results are shown in Table 2.
“◯”: No cracking of the solder resist was observed, and neither the solder resist was lifted nor peeled off.
"X": Any of the above is recognized.

[Evaluation of HAST resistance]
Comb having a line / space of 50 μm / 50 μm by etching the copper surface of a printed wiring board substrate (MCL E-679, manufactured by Hitachi Chemical Co., Ltd., product name) in which a 12 μm thick copper foil is laminated on a glass epoxy substrate. A mold electrode was formed. This substrate was used as an evaluation substrate, and a cured resist (permanent resist film) was formed on the substrate as described above, and then tested under conditions of 130 ° C., 85% RH, 5V for 100 hours. Thereafter, the degree of migration was observed with a 100-fold metal microscope, and HAST resistance was evaluated according to the following criteria. The evaluation results are shown in Table 2.
“◯”: No permanent migration occurred in the permanent resist film.
“×”: A large migration occurred

  The use of the epoxy resin of Examples 1 to 5 (d) having a chlorine content of 500 ppm or less and the method for forming a resist pattern treated with an aqueous solution containing a divalent metal ion are particularly excellent in HAST resistance. Moreover, it is excellent also in resolution, opening shape, and gold-plating tolerance. When the amount of chlorine contained in the epoxy resin is large as in Comparative Examples 3 and 4, the Comparative Example 3 was washed with ion-exchanged water by rinsing with rinsing water containing divalent metal ions (Comparative Example 4). In this case, the resolution and the aperture shape tend to be improved. Further, as in Comparative Examples 1 and 2, even when the amount of chlorine contained in the epoxy resin is small, washing with normal ion-exchanged water is inferior in HAST resistance and resolution and opening shape. Thus, it is necessary to treat with an aqueous solution containing a divalent metal ion using a low chlorine content epoxy resin.

  In the photosensitive resin compositions of Examples 1 to 5, FA-321M (tricyclodecane dimethanol dimethacrylate) and UX-5002D-M20 (tricyclodecane structure-containing urethane acrylate) are used in combination, and the characteristics are excellent. You can see that

  According to the present invention, a solder resist that is excellent in resolution, opening shape, Ni / Au plating resistance, solder heat resistance, HAST resistance, and optimal for printed wiring boards, semiconductor package substrates, and flexible wiring boards. The photosensitive dry film which can form can be provided.

Claims (4)

  On the substrate, (a) a resin having an ethylenically unsaturated group and a carboxyl group, (b) a photopolymerizable monomer having an ethylenically unsaturated group, (c) a photopolymerization initiator, and (d) containing chlorine And a photosensitive layer comprising a photosensitive resin composition containing an epoxy resin having an amount of 500 ppm or less, and curing a predetermined portion of the photosensitive layer with actinic rays, and then removing the photosensitive layer region other than the predetermined portion. A method of forming a resist pattern, comprising treating with an aqueous solution containing a divalent metal ion. The method for forming a resist pattern according to claim 1, wherein the divalent metal ion is at least one metal ion selected from Ca ²⁺ , Mg ²⁺ , Sr ²⁺ , and Ba ²⁺ .   A permanent mask resist produced by the method for forming a resist pattern according to claim 1. A photosensitive layer made of a photosensitive resin composition is provided on a substrate, and a predetermined portion of the photosensitive layer is cured with actinic rays, and then the photosensitive layer region other than the predetermined portion is removed to contain a divalent metal ion. A photosensitive resin composition used in a method for forming a resist pattern, which is processed using an aqueous solution,
The photosensitive resin composition is
(A) a resin having an ethylenically unsaturated group and a carboxyl group; (b) a photopolymerizable monomer having an ethylenically unsaturated group; (c) a photopolymerization initiator; and (d) a chlorine content of 500 ppm or less. A photosensitive resin composition comprising an epoxy resin.