Photosensitive resin composition, photosensitive element, printed wiring board, and method for manufacturing printed wiring board

Abstract

An aspect of the present invention relates to a method for manufacturing a printed wiring board, the method comprising: a step for forming a first photosensitive layer on a substrate; a step for exposing and developing the first photosensitive layer to form a first resist pattern on the substrate; a step for forming a second photosensitive layer on the first resist pattern; a step for exposing and developing the second photosensitive layer to form a second resist pattern on the first resist pattern; and a step for curing the first resist pattern and the second resist pattern to form a first permanent resist layer and a second permanent resist layer, wherein the second permanent resist layer is a protruding dam for preventing the outflow of underfill.

Description

Photosensitive resin composition, photosensitive element, printed circuit board, and method for manufacturing a printed circuit board.

[0001] This disclosure relates to a photosensitive resin composition, a photosensitive element, a printed circuit board, and a method for manufacturing a printed circuit board.

[0002] In the field of printed circuit boards (PCBs), permanent resist is formed on the PCBs. Permanent resist plays a role in preventing corrosion of the conductor layer and maintaining electrical insulation between conductor layers during the use of the PCB. In recent years, permanent resist has also taken on the role of a solder resist film in processes such as flip-chip mounting and wire bonding mounting of semiconductor elements onto PCBs via solder, preventing solder from adhering to unwanted areas of the conductor layer on the PCB.

[0003] To prevent the leakage of underfill (encapsulating resin) used in flip-chip mounting, semiconductor package substrates have been proposed that form a dam using a permanent resist. For example, Patent Document 1 discloses a method for manufacturing a printed circuit board in which a resin insulating layer having a thermosetting resin composition layer and a photocurable resin composition layer is formed on the surface of the substrate, and then the photocurable resin composition layer is patterned by photolithography to form a dam that prevents the underfill from spreading.

[0004] Japanese Patent Publication No. 2013-131714

[0005] When a dam to prevent underfill leakage is formed by exposure and development of a photosensitive layer made from a photosensitive resin composition, the photosensitive layer other than the dam-forming portion is removed by development. If the solubility of the photosensitive layer in the developer is insufficient, insoluble components derived from the photosensitive resin composition may form scum and adhere to the substrate, equipment, etc.

[0006] The present disclosure aims to provide a photosensitive resin composition and a photosensitive element that have excellent solubility in developing solutions and can form a dam to prevent underfill leakage, as well as a printed circuit board equipped with a dam to prevent underfill leakage and a method for manufacturing a printed circuit board.

[0007] One aspect of the present disclosure relates to the following photosensitive resin composition, photosensitive element, method for manufacturing a printed circuit board, and printed circuit board: [1] A method for manufacturing a printed circuit board, comprising the steps of: forming a first photosensitive layer on a substrate; exposing and developing the first photosensitive layer to form a first resist pattern on the substrate; forming a second photosensitive layer on the first resist pattern; exposing and developing the second photosensitive layer to form a second resist pattern on the first resist pattern; and curing the first resist pattern and the second resist pattern to form a first permanent resist layer and a second permanent resist layer, wherein the second permanent resist layer is a protruding dam for preventing underfill leakage. [2] The method for manufacturing a printed circuit board according to [1], further comprising the step of post-exposing the first resist pattern after forming the first resist pattern and before forming the second photosensitive layer. [3] The method for manufacturing a printed circuit board according to [1], further comprising the steps of post-exposing and post-heating the first resist pattern after forming the first resist pattern and before forming the second photosensitive layer. [4] The method for manufacturing a printed circuit board, comprising the steps of forming a first photosensitive layer on a substrate and exposing the first photosensitive layer; forming a second photosensitive layer on the first photosensitive layer after exposure and exposing the second photosensitive layer; developing the first and second photosensitive layers after exposure to simultaneously form a first resist pattern and a second resist pattern on the substrate; and curing the first and second resist patterns to form a first permanent resist layer and a second permanent resist layer, wherein the second permanent resist layer is a protruding dam for preventing underfill from flowing out.[5] The method for manufacturing a printed circuit board according to any one of [1] to [4], wherein the second permanent resist layer comprises a cured product of a photosensitive resin composition containing (A) an acid-modified vinyl group-containing resin, (B) a thermosetting resin, (C) a photopolymerizable compound, and (D) a photopolymerization initiator, and the (A) acid-modified vinyl group-containing resin comprises one type of acid-modified vinyl group-containing resin, or comprises two or more types of acid-modified vinyl group-containing resins, and the difference in the values ​​obtained by dividing the weight-average molecular weight of each of the two or more acid-modified vinyl group-containing resins by their acid value is 30 or less. [6] The method for manufacturing a printed circuit board according to [5], wherein the (A) acid-modified vinyl group-containing resin comprises two or more types of acid-modified vinyl group-containing resins, and the difference in the values ​​obtained by dividing the weight-average molecular weight of each of the two or more acid-modified vinyl group-containing resins by their acid value is 30 or less. [7] The method for producing a printed circuit board according to [6], wherein the (A) acid-modified vinyl group-containing resin comprises two or more selected from the group consisting of urethane-type acid-modified epoxy (meth)acrylate, phenol novolac-type acid-modified epoxy (meth)acrylate, and bisphenol-type acid-modified epoxy (meth)acrylate. [8] The method for producing a printed circuit board according to any one of [5] to [7], wherein the photosensitive resin composition further comprises (E) an inorganic filler. [9] The method for producing a printed circuit board according to any one of [5] to [8], wherein the photosensitive resin composition further comprises (F) a pigment.

[10] The method for producing a printed circuit board according to any one of [5] to [9], wherein the photosensitive resin composition further comprises (G) an elastomer.

[11] A photosensitive resin composition for forming a dam to prevent underfill outflow, wherein the (A) acid-modified vinyl group-containing resin comprises (B) a thermosetting resin, (C) a photopolymerizable compound, and (D) a photopolymerization initiator, wherein the (A) acid-modified vinyl group-containing resin comprises one type of acid-modified vinyl group-containing resin, or comprises two or more types of acid-modified vinyl group-containing resins, and the difference in the values ​​obtained by dividing the weight-average molecular weight of each of the two or more acid-modified vinyl group-containing resins by their acid value is 30 or less.

[12] The photosensitive resin composition according to

[11] , wherein the (A) acid-modified vinyl group-containing resin comprises two or more types of acid-modified vinyl group-containing resins, and the difference in the values ​​obtained by dividing the weight-average molecular weight of each of the two or more acid-modified vinyl group-containing resins by their acid value is 30 or less.

[13] The photosensitive resin composition according to

[12] , wherein the (A) acid-modified vinyl group-containing resin comprises two or more selected from the group consisting of urethane-type acid-modified epoxy (meth)acrylate, phenol novolac-type acid-modified epoxy (meth)acrylate, and bisphenol-type acid-modified epoxy (meth)acrylate.

[14] The photosensitive resin composition according to any one of

[11] to

[13] , further comprising (E) an inorganic filler.

[15] The photosensitive resin composition according to any one of

[11] to

[14] , further comprising (F) a pigment.

[16] The photosensitive resin composition according to any one of

[11] to

[15] , further comprising (G) an elastomer.

[17] A photosensitive element comprising a support film and a photosensitive layer formed on the support film using the photosensitive resin composition according to any one of

[11] to

[16] .

[18] A printed circuit board comprising a substrate, a first permanent resist layer formed on the substrate, and a second permanent resist layer formed on the first permanent resist layer, wherein the second permanent resist layer is a protruding dam for preventing underfill from flowing out, and includes a cured product of the photosensitive resin composition described in any of

[11] to

[16] .

[0008] According to this disclosure, it is possible to provide a photosensitive resin composition and a photosensitive element that have excellent solubility in a developing solution and can form a dam to prevent underfill from flowing out, as well as a printed circuit board equipped with a dam to prevent underfill from flowing out, and a method for manufacturing a printed circuit board.

[0009] Figure 1 is a schematic cross-sectional view showing a photosensitive element according to this embodiment. Figure 2 is a schematic cross-sectional view showing a printed circuit board according to this embodiment.

[0010] The present disclosure is described in detail below. In this specification, the term "process" includes not only independent processes but also processes that are indistinguishable from other processes as long as the intended function of the process is achieved. The term "layer" includes not only structures that are formed on the entire surface when viewed as a plan view, but also structures that are formed on only a part of the surface. Numerical ranges indicated using "~" indicate a range that includes the numbers written before and after "~" as the minimum and maximum values, respectively. In numerical ranges described stepwise in this specification, the upper or lower limit of a numerical range in one step may be replaced with the upper or lower limit of a numerical range in another step. In numerical ranges described in this specification, the upper or lower limit of a numerical range may be replaced with the values ​​shown in the examples.

[0011] In this specification, when referring to the amount of each component in a composition, if there are multiple substances corresponding to each component in the composition, unless otherwise specified, it refers to the total amount of those multiple substances present in the composition. In this specification, "(meth)acryloyl" means at least one of "acryloyl" and its corresponding "methacryloyl," and the same applies to other similar expressions such as "(meth)acrylic acid" and "(meth)acrylate." In this specification, "solids" refers to the non-volatile components contained in a photosensitive resin composition excluding volatile substances (water, solvents, etc.), and includes components that are liquid, syrup-like, or waxy at room temperature (around 25°C).

[0012] [Photosensitive Resin Composition] The photosensitive resin composition according to this embodiment contains (A) an acid-modified vinyl group-containing resin, (B) a thermosetting resin, (C) a photopolymerization initiator, and (D) a photopolymerizable compound, wherein (A) the acid-modified vinyl group-containing resin contains one type of acid-modified vinyl group-containing resin, or contains two or more types of acid-modified vinyl group-containing resins, and the difference in the values ​​obtained by dividing the weight-average molecular weight of each of the two or more acid-modified vinyl group-containing resins by their acid value is 30 or less. This is a photosensitive resin composition for forming a dam to prevent underfill outflow.

[0013] The photosensitive resin composition according to this embodiment is a negative-type photosensitive resin composition, and the cured film of the photosensitive resin composition can be suitably used as a permanent resist. The components used in the photosensitive resin composition of this embodiment will be described in more detail below.

[0014] (Component (A): Acid-modified vinyl group-containing resin) The photosensitive resin composition according to this embodiment contains an acid-modified vinyl group-containing resin as component (A). Component (A) is not particularly limited as long as it has a photopolymerizable ethylenically unsaturated bond and an alkali-soluble acidic group. Component (A) may be used alone or in combination of two or more types.

[0015] Examples of groups having ethylenically unsaturated bonds in component (A) include vinyl groups, allyl groups, propargyl groups, butenyl groups, ethynyl groups, phenylethynyl groups, maleimide groups, nadiimide groups, and (meth)acryloyl groups. Among these, (meth)acryloyl groups are preferred from the viewpoint of reactivity and resolution. Examples of acidic groups in component (A) include carboxyl groups, sulfol groups, and phenolic hydroxyl groups. Among these, carboxyl groups are preferred from the viewpoint of resolution.

[0016] Component (A) is preferably an acid-modified vinyl group-containing epoxy derivative obtained by reacting a resin (A') obtained by reacting (a) an epoxy resin (hereinafter referred to as "component (a)") with (b) an ethylenically unsaturated group-containing organic acid (hereinafter referred to as "component (b)") with (c) a saturated or unsaturated group-containing polybasic acid anhydride (hereinafter referred to as "component (c)").

[0017] Examples of acid-modified vinyl group-containing epoxy derivatives include acid-modified epoxy (meth)acrylate. Acid-modified epoxy (meth)acrylate is a resin obtained by acid-modifying epoxy (meth)acrylate, which is a reaction product of component (a) and component (b), with component (c). As acid-modified epoxy (meth)acrylate, for example, an addition product obtained by adding a saturated or unsaturated polybasic acid anhydride to an esterified product obtained by reacting an epoxy resin with a vinyl group-containing monocarboxylic acid can be used.

[0018] (a) Examples of components include novolac-type epoxy resins, bisphenol novolac-type epoxy resins, bisphenol-type epoxy resins, trisphenolmethane-type epoxy resins, and biphenyl-type epoxy resins.

[0019] Examples of novolac-type epoxy resins include phenol novolac-type epoxy resins and cresol novolac-type epoxy resins.

[0020] Examples of phenol novolac type epoxy resins or cresol novolac type epoxy resins include YDCN-701, YDCN-702, YDCN-703, YDCN-704, YDCN-704L, YDPN-638, YDPN-602 (all manufactured by Nippon Steel Chemical & Material Co., Ltd., product names), DEN-431, DEN-439 (both manufactured by Dow Chemical Company, product names), EOCN-120, EOCN-102S, E OCN-103S, EOCN-104S, EOCN-1012, EOCN-1025, EOCN-1027, BREN (all manufactured by Nippon Kayaku Co., Ltd., trade names), EPN-1138, EPN-1235, EPN-1299 (all manufactured by BASF, trade names), N-730, N-770, N-865, N-665, N-673, VH-4150, VH-4240 (all manufactured by DIC Corporation, trade names), etc., are commercially available.

[0021] Examples of bisphenol novolac type epoxy resins include bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, and bisphenol E novolac type epoxy resin.

[0022] Bisphenol F novolac epoxy resins are commercially available, for example, as the EXA-7376 series (manufactured by DIC Corporation, trade name), and bisphenol A novolac epoxy resins are commercially available, for example, as the EPON SU8 series (manufactured by Mitsubishi Chemical Corporation, trade name).

[0023] Examples of bisphenol-type epoxy resins include bisphenol A type epoxy resin and bisphenol F type epoxy resin.

[0024] Examples of commercially available bisphenol A type epoxy resins or bisphenol F type epoxy resins include jER807, jER815, jER825, jER827, jER828, jER834, jER1001, jER1004, jER1007, jER1009 (all manufactured by Mitsubishi Chemical Corporation, trade names), DER-330, DER-301, DER-361 (all manufactured by Dow Chemical Company, trade names), YD-8125, YDF-170, YDF-175S, YDF-2001, YDF-2004, YDF-8170 (all manufactured by Nippon Steel Chemical & Material Co., Ltd., trade names).

[0025] Examples of trisphenolmethane-type epoxy resins that are commercially available include FAE-2500, EPPN-501H, and EPPN-502H (all manufactured by Nippon Kayaku Co., Ltd., trade names).

[0026] Examples of commercially available biphenyl-type epoxy resins include NC-3000, NC-3000-L, NC-3000-H, NC-3000-FH-75M, NC-3100, and CER-3000-L (all manufactured by Nippon Kayaku Co., Ltd., trade names).

[0027] (b) Examples of components include acrylic acid derivatives such as acrylic acid, acrylic acid dimers, methacrylic acid, β-furfurylacrylic acid, β-styrylacrylic acid, cinnamic acid, crotonic acid, and α-cyanocinnamic acid; semi-ester compounds which are reaction products of hydroxyl group-containing (meth)acrylates and dibasic acid anhydrides; and semi-ester compounds which are reaction products of vinyl group-containing monoglycidyl ethers or vinyl group-containing monoglycidyl esters and dibasic acid anhydrides. Component (b) may be used individually or in combination of two or more.

[0028] Semi-ester compounds can be obtained, for example, by reacting a hydroxyl group-containing (meth)acrylate, a vinyl group-containing monoglycidyl ether, or a vinyl group-containing monoglycidyl ester with a dibasic acid anhydride.

[0029] Examples of hydroxyl group-containing (meth)acrylates, vinyl group-containing monoglycidyl ethers, and vinyl group-containing monoglycidyl esters include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, polyethylene glycol mono(meth)acrylate, trimethylolpropanedi(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and glycidyl (meth)acrylate.

[0030] Examples of dibasic acid anhydrides include succinic anhydride, maleic anhydride, tetrahydrophthalic anhydride, phthalic anhydride, methyltetrahydrophthalic anhydride, ethyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, ethylhexahydrophthalic anhydride, and itaconic anhydride.

[0031] Component (A'), obtained by reacting component (a) and component (b), has a hydroxyl group formed by a ring-opening addition reaction between the epoxy group of component (a) and the carboxyl group of component (b). By further reacting component (A') with component (c), an acid-modified vinyl group-containing resin is obtained in which the hydroxyl groups of component (A') (including the hydroxyl groups originally present in component (a)) and the acid anhydride group of component (c) are semi-esterified.

[0032] Examples of component (c) include succinic anhydride, maleic anhydride, tetrahydrophthalic anhydride, phthalic anhydride, methyltetrahydrophthalic anhydride, ethyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, ethylhexahydrophthalic anhydride, and itaconic anhydride. Among these, tetrahydrophthalic anhydride is preferred from the viewpoint of resolution. Component (c) may be used alone or in combination of two or more.

[0033] If necessary, hydrogenated bisphenol A epoxy resin may be partially used as component (a), and styrene-maleic acid resins such as hydroxyethyl (meth)acrylate modified styrene-maleic anhydride copolymers may also be partially used.

[0034] Component (A) can be synthesized by a known method, or commercially available products may be used. Examples of acid-modified cresol novolak type epoxy (meth)acrylate include CCR-1291H, CCR-1235, CCR-1373H, CCR-1374H (above, trade names of Nippon Kayaku Co., Ltd.), etc., which are commercially available. Examples of acid-modified biphenyl type epoxy (meth)acrylate include ZCR-1569H, ZCR-1601H, ZCR-1797H, ZCR-1798H (above, trade names of Nippon Kayaku Co., Ltd.), etc., which are commercially available. Examples of acid-modified bisphenol F type epoxy (meth)acrylate include ZFR-1401H, ZFR-1491H, ZFR-1533H (above, trade names of Nippon Kayaku Co., Ltd.), etc., which are commercially available. Examples of acid-modified bisphenol A type epoxy (meth)acrylate include ZAR-1035, ZAR-2000 (above, trade names of Nippon Kayaku Co., Ltd.), etc., which are commercially available.

[0035] From the viewpoint of improving the mechanical strength of the cured film of the photosensitive resin composition, an acid-modified vinyl group-containing resin having a urethane bond may be used as component (A). The acid-modified vinyl group-containing resin having a urethane bond may be a urethane type acid-modified epoxy (meth)acrylate obtained by reacting an epoxy (meth)acrylate compound having two or more hydroxyl groups and an ethylenically unsaturated group, a diisocyanate compound, and a diol compound having a carboxy group.

[0036] The urethane type acid-modified epoxy (meth)acrylate can be synthesized by a known synthesis method, or commercially available products may be used. The urethane type acid-modified epoxy (meth)acrylate can be synthesized, for example, by the method described in JP-A-2016-199719. Examples of the urethane type acid-modified epoxy (meth)acrylate include UXE-3011, UXE-3012, UXE-3024 (above, trade names of Nippon Kayaku Co., Ltd.), etc., which are commercially available.

[0037] When the component (A) contains two or more acid-modified vinyl group-containing resins, the component (A) may contain two or more selected from the group consisting of urethane-type acid-modified epoxy (meth)acrylate, phenol novolak-type acid-modified epoxy (meth)acrylate, and bisphenol-type acid-modified epoxy (meth)acrylate.

[0038] From the viewpoint of improving the solubility of the photosensitive layer in the developer, the acid value of the component (A) may be 40 mgKOH / g or more, 45 mgKOH / g or more, 50 mgKOH / g or more, or 55 mgKOH / g or more. From the viewpoint of improving the electrical properties of the cured film, the acid value of the component (A) may be 130 mgKOH / g or less, 120 mgKOH / g or less, 110 mgKOH / g or less, or 100 mgKOH / g or less. From the above viewpoints, the acid value of the component (A) may be 40 to 130 mgKOH / g, 45 to 120 mgKOH / g, 50 to 110 mgKOH / g, or 55 to 100 mgKOH / g.

[0039] The acid value can be measured by the following procedure. First, 1 g of the acid-modified vinyl group-containing resin to be measured for the acid value is precisely weighed, and then 30 g of acetone is added to the acid-modified vinyl group-containing resin to dissolve it uniformly to obtain a solution. Next, an appropriate amount of phenolphthalein as an indicator is added to the solution, and then titration is performed using a 0. N KOH (potassium hydroxide) aqueous solution. The acid value is determined by calculating the mass (unit: mg) of KOH required to neutralize the acetone solution of the acid-modified vinyl group-containing resin.

[0040] From the viewpoint of improving the adhesion of the cured film, the weight average molecular weight (Mw) of the component (A) may be 3000 or more, 4000 or more, 5000 or more, 6000 or more, or 7000 or more. From the viewpoint of improving the developability of the photosensitive layer, the Mw of the component (A) may be 20000 or less, 19000 or less, 18000 or less, 17000 or less, or 16000 or less. From the above viewpoints, the Mw of the component (A) may be 3000 to 20000, 4000 to 19000, 五千至一万八千, 六千至一万七千, or 7000 to 16000.

[0041] Mw can be measured by gel permeation chromatography (GPC). For example, Mw can be measured under the GPC conditions described below, and the value converted using a calibration curve for standard polystyrene can be used as the Mw value. A set of five samples ("PStQuick MP-H" and "PStQuick B," manufactured by Tosoh Corporation) can be used as the standard polystyrene to create the calibration curve. GPC instrument: High-speed GPC instrument "HCL-8320GPC" (manufactured by Tosoh Corporation) Detector: Differential refractometer or UV detector (manufactured by Tosoh Corporation) Column: TSKgel SuperMultipore HZ-H column (column length: 15 cm, column inner diameter: 4.6 mm) (manufactured by Tosoh Corporation) Eluent: Tetrahydrofuran (THF) Measurement temperature: 40°C Flow rate: 0.35 mL / min Sample concentration: 10 mg / THF 5 mL Injection volume: 20 μL

[0042] (A) The value obtained by dividing the weight-average molecular weight (Mw) of component by the acid value (Mw / acid value) may be 80 or more, 90 or more, 100 or more, 110 or more, or 120 or more from the viewpoint of improving the solubility of the photosensitive layer in the developer, and may be 250 or less, 240 or less, 230 or less, 220 or less, or 210 or less from the viewpoint of improving the insulation reliability of the cured film. From the above viewpoint, the Mw / acid value may be 80 to 250, 90 to 240, 100 to 230, 110 to 220, or 120 to 210.

[0043] (A) By combining resins with small differences in Mw / acid value between components, the solubility of the photosensitive layer in the developer can be improved. (A) The difference in Mw / acid value between components may be 30 or less, 29 or less, 28 or less, 27 or less, or 26 or less, from the viewpoint of further improving the solubility of the photosensitive layer in the developer. (A) The difference in Mw / acid value between components may be 0.

[0044] The content of component (A) in the photosensitive resin composition may be 20 to 70% by mass, 25 to 60% by mass, or 30 to 50% by mass, based on the total solid content of the photosensitive resin composition, from the viewpoint of improving the heat resistance, electrical properties, and chemical resistance of the permanent resist.

[0045] (Component (B): Thermosetting resin) The photosensitive resin composition according to this embodiment can improve the heat resistance, adhesion, and chemical resistance of the cured film (permanent resist) formed from the photosensitive resin composition by using a thermosetting resin as component (B). Component (B) may be used alone or in combination of two or more types.

[0046] Examples of component (B) include epoxy resins, phenolic resins, unsaturated imide resins, cyanate resins, isocyanate resins, benzoxazine resins, oxetane resins, amino resins, unsaturated polyester resins, allyl resins, dicyclopentadiene resins, silicone resins, triazine resins, and melamine resins.

[0047] Examples of epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, hydrogenated bisphenol A type epoxy resin, brominated bisphenol A type epoxy resin, bisphenol S type epoxy resin, novolac type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, hydantoin type epoxy resin, triglycidyl isocyanurate, and bixylenol type epoxy resin.

[0048] The content of component (B) may be 2 to 30% by mass, 5 to 25% by mass, or 8 to 20% by mass, based on the total solid content of the photosensitive resin composition. When the content of component (B) is within the above range, the heat resistance of the formed cured film can be further improved while maintaining good developability.

[0049] (Component (C): Photopolymerization initiator) The photosensitive resin composition according to this embodiment contains a photopolymerization initiator as component (C). Component (C) is not particularly limited as long as it can polymerize components (A) and (D). Component (C) may be used alone or in combination of two or more types.

[0050] (C) Component may include, for example, benzoin compounds such as benzoin, benzoin methyl ether, and benzoin isopropyl ether; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexylphenyl ketone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1,2-methyl-[4-(methylthio)phenyl]-2-morpholino-1-propane, N,N-dimethylaminophenyl Acetophenone compounds such as tylaminoacetophenone; anthraquinone compounds such as 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, and 2-aminoanthraquinone; thioxanthone compounds such as 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, and 2,4-diisopropylthioxanthone; ketal compounds such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzo Benzophenone compounds such as phenone, methylbenzophenone, 4,4'-dichlorobenzophenone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(dimethylamino)benzophenone, and 4-benzoyl-4'-methyldiphenyl sulfide; 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, 2-(o-chlorophenyl)-4,5-di(m-methoxyphenyl)imidazole dimer, 2-(o-fluorophenyl)-4,5-diphenylimidazole dimer, and 2-(o-methoxyphenyl) Imidazole compounds such as phenyl)-4,5-diphenylimidazole dimer, 2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer, 2,4-di(p-methoxyphenyl)-5-phenylimidazole dimer, and 2-(2,4-dimethoxyphenyl)-4,5-diphenylimidazole dimer; acridine compounds such as 9-phenylacridine and 1,7-bis(9,9'-acridinyl)heptane; and acylphosphine oxide compounds such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide.Examples include oxime ester compounds such as 1,2-octanedione-1-[4-(phenylthio)phenyl]-2-(O-benzoyl oxime), 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]ethanone 1-(O-acetyl oxime), and 1-phenyl-1,2-propanedione-2-[O-(ethoxycarbonyl)oxime]; and tertiary amine compounds such as ethyl N,N-dimethylaminobenzoate, isoamyl N,N-dimethylaminobenzoate, pentyl-4-dimethylaminobenzoate, triethylamine, and triethanolamine.

[0051] The content of component (C) is not particularly limited, but may be 0.2 to 15% by mass, 0.5 to 10% by mass, 0.8 to 5% by mass, or 1 to 3% by mass, based on the total solid content of the photosensitive resin composition. If the content of component (C) is 0.2% by mass or more, the exposed area will be less likely to dissolve during development, and if it is 15% by mass or less, the decrease in heat resistance will be more easily suppressed.

[0052] (Component (D): Photopolymerizable compound) The photosensitive resin composition according to this embodiment contains a photopolymerizable compound as component (D). Component (D) is not particularly limited as long as it is a compound having a functional group that exhibits photopolymerization. Examples of functional groups that exhibit photopolymerization include groups having an ethylenically unsaturated bond, such as vinyl group, allyl group, propargyl group, butenyl group, ethynyl group, phenylethynyl group, maleimide group, nadiimide group, and (meth)acryloyl group. From the viewpoint of reactivity, component (D) may also include a compound having a (meth)acryloyl group. Component (D) may be used alone or in combination of two or more types.

[0053] (D) Component includes, for example, hydroxyalkyl (meth)acrylate compounds such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate; mono- or di(meth)acrylate compounds of glycols such as ethylene glycol, methoxytetraethylene glycol, and polyethylene glycol; (meth)acrylamide compounds such as N,N-dimethyl(meth)acrylamide and N-methylol(meth)acrylamide; aminoalkyl (meth)acrylate compounds such as N,N-dimethylaminoethyl (meth)acrylate; hexanediol, trimethylolpropane, pentaerythritol, ditrimethylolpropane Examples include polyhydric (meth)acrylate compounds of polyhydric alcohols such as pan, dipentaerythritol, and tris-hydroxyethyl isocyanurate, or their ethylene oxide or propylene oxide adducts; (meth)acrylate compounds of ethylene oxide or propylene oxide adducts of phenolic compounds such as phenoxyethyl (meth)acrylate and polyethoxydi(meth)acrylate of bisphenol A; (meth)acrylate compounds of glycidyl ethers such as glycerin diglycidyl ether, trimethylolpropane triglycidyl ether, and triglycidyl isocyanurate; and melamine (meth)acrylate.

[0054] The content of component (D) may be 1 to 15% by mass, 2 to 10% by mass, or 4 to 8% by mass, based on the total solid content of the photosensitive resin composition, from the viewpoint of forming a permanent resist that exhibits higher resolution and a good resist pattern shape while also having excellent heat resistance and thermal shock resistance. If the content of component (D) is 1% by mass or more, the photosensitivity is improved and the exposed area is less likely to dissolve during development, and if it is 15% by mass or less, the heat resistance of the permanent resist is more easily improved.

[0055] (Component (E): Inorganic Filler) The photosensitive resin composition according to this embodiment may further contain an inorganic filler as component (E). By including component (E), the adhesive strength and hardness of the permanent resist can be improved. Component (E) may be used alone or in combination of two or more types.

[0056] Examples of inorganic fillers include silica, alumina, titania, tantalum oxide, zirconia, silicon nitride, barium titanate, barium carbonate, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, lead titanate, lead zirconate titanate, lead lanthanum zirconate titanate, gallium oxide, spinel, mullite, cordierite, talc, aluminum titanate, yttria-containing zirconia, barium silicate, boron nitride, calcium carbonate, barium sulfate, calcium sulfate, zinc oxide, magnesium titanate, hydrotalcite, mica, calcined kaolin, and carbon.

[0057] Component (E) may contain silica from the viewpoint of improving the heat resistance of the permanent resist, may contain barium sulfate from the viewpoint of improving the heat resistance and adhesive strength of the permanent resist, or may contain both silica and barium sulfate. From the viewpoint of improving the dispersibility of the inorganic filler, an inorganic filler that has been pre-surface-treated with alumina or an organosilane compound may be used.

[0058] The average particle size of the inorganic filler may be 0.01 to 5.0 μm, 0.05 to 3.0 μm, 0.1 to 2.0 μm, or 0.15 to 1.0 μm, from the viewpoint of resolution.

[0059] The average particle size of component (E) is the average particle size of the inorganic filler dispersed in the photosensitive resin composition, and is the value obtained by measurement as follows: First, the photosensitive resin composition is diluted 1000 times with methyl ethyl ketone, and then the particles dispersed in the solvent are measured using a submicron particle analyzer (Beckman Coulter, Inc., product name "N5") in accordance with the international standard ISO 13321, with a refractive index of 1.38, and the particle diameter at 50% of the cumulative value (by volume) in the particle size distribution is taken as the average particle size.

[0060] The content of component (E) may be 5 to 70% by mass, 6 to 60% by mass, or 10 to 50% by mass, based on the total solid content of the photosensitive resin composition. When the content of component (E) is within the above range, the low coefficient of thermal expansion, heat resistance, and film strength can be further improved.

[0061] When silica is used as component (E), the silica content may be 5 to 60% by mass, 10 to 55% by mass, or 15 to 50% by mass, based on the total solid content of the photosensitive resin composition. When barium sulfate is used as component (E), the barium sulfate content may be 5 to 30% by mass, 5 to 25% by mass, or 8 to 20% by mass, based on the total solid content of the photosensitive resin composition. When the silica and barium sulfate content is within the above ranges, the composition tends to exhibit a low coefficient of thermal expansion, excellent solder heat resistance, and superior adhesive strength.

[0062] (Component (F): Pigment) The photosensitive resin composition according to this embodiment may further contain a pigment as component (F) from the viewpoint of improving the identifiability or appearance of the manufacturing apparatus. As component (F), a coloring agent that produces a desired color when concealing wiring (conductor patterns) can be used. Component (F) may be used alone or in combination of two or more types.

[0063] Examples of component (F) include phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium dioxide, carbon black, and naphthalene black.

[0064] (F) The content of component (F) may be 0.01 to 5.0% by mass, 0.03 to 3.0% by mass, or 0.05 to 2.0% by mass, based on the total amount of solids in the photosensitive resin composition, from the viewpoint of making the manufacturing equipment easier to identify and better concealing the wiring.

[0065] (Component (G): Elastomer) The photosensitive resin composition according to this embodiment may further contain an elastomer as component (G). By including component (G), it is possible to suppress the decrease in flexibility and adhesive strength caused by internal stress (strain) inside the resin due to curing shrinkage of component (A).

[0066] Examples of component (G) include styrene elastomers, olefin elastomers, urethane elastomers, polyester elastomers, polyamide elastomers, acrylic elastomers, and silicone elastomers. These elastomers are composed of hard segment components that contribute to heat resistance and strength, and soft segment components that contribute to flexibility and toughness. Among these, olefin elastomers and polyester elastomers are preferred.

[0067] Examples of olefin-based elastomers include ethylene-propylene copolymers, ethylene-α-olefin copolymers, ethylene-α-olefin-non-conjugated diene copolymers, propylene-α-olefin copolymers, butene-α-olefin copolymers, ethylene-propylene-diene copolymers, copolymers of non-conjugated dienes such as dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, methylenenorbornene, ethylidenenorbornene, butadiene, and isoprene with α-olefins, epoxy-modified polybutadiene, and carboxylic acid-modified butadiene-acrylonitrile copolymers.

[0068] Epoxy-modified polybutadiene preferably has hydroxyl groups at its molecular ends, more preferably at both molecular ends, and even more preferably at only both molecular ends. The number of hydroxyl groups in epoxy-modified polybutadiene may be one or more, preferably 1 to 5, more preferably 1 or 2, and even more preferably 2.

[0069] As the polyester elastomer, a compound obtained by polycondensation of a dicarboxylic acid or its derivative with a diol compound or its derivative can be used.

[0070] Examples of dicarboxylic acids include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid; aliphatic dicarboxylic acids having 2 to 20 carbon atoms such as adipic acid, sebacic acid, and dodecanedicarboxylic acid; and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. Dicarboxylic acids can be used individually or in combination of two or more.

[0071] Examples of diol compounds include aliphatic diols such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, and 1,10-decanediol; alicyclic diols such as 1,4-cyclohexanediol; and aromatic diols such as bisphenol A, bis-(4-hydroxyphenyl)methane, bis-(4-hydroxy-3-methylphenyl)propane, and resorcinol.

[0072] As a polyester elastomer, a multiblock copolymer can be used in which aromatic polyester (e.g., polybutylene terephthalate) is used as the hard segment component and aliphatic polyester (e.g., polytetramethylene glycol) is used as the soft segment component. Various grades of polyester elastomers exist depending on the type, ratio, and molecular weight of the hard and soft segments.

[0073] Component (G) may include a carboxylic acid-modified butadiene-acrylonitrile copolymer or a polyester elastomer having hydroxyl groups, from the viewpoint of improving the adhesion of the cured film.

[0074] The content of component (G) may be 2 to 40 parts by mass, 4 to 30 parts by mass, 6 to 20 parts by mass, or 10 to 15 parts by mass per 100 parts by mass of component (A). When the content of component (G) is within the above range, the elastic modulus of the cured film in the high-temperature region becomes lower, and the unexposed areas become more easily eluted by the developer. The content of component (G) may be 1 to 25% by mass, 2 to 20% by mass, 3 to 15% by mass, or 4 to 10% by mass based on the total solid content of the photosensitive resin composition.

[0075] (Other components) The photosensitive resin composition according to this embodiment may further contain various additives as needed. Examples of additives include polymerization inhibitors such as hydroquinone, methylhydroquinone, hydroquinone monomethyl ether, catechol, and pyrogallol; thickeners such as bentonite and montmorillonite; silicone-based, fluorine-based, and vinyl resin-based defoaming agents; silane coupling agents; and flame retardants such as brominated epoxy compounds, acid-modified brominated epoxy compounds, antimony compounds, phosphate compounds, aromatic condensed phosphate esters, and halogen-containing condensed phosphate esters.

[0076] (Solvent) The photosensitive resin composition according to this embodiment contains a solvent to dissolve and disperse each component, thereby facilitating application to a substrate and forming a coating film of uniform thickness.

[0077] Examples of solvents include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as methyl cellosolve, butyl cellosolve, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, 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 hydrocarbons such as octane and decane; and petroleum-based solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha. Solvents may be used individually or in combination of two or more.

[0078] The amount of solvent is not particularly limited, but the proportion of solvent in the photosensitive resin composition may be 10 to 50% by mass, 20 to 40% by mass, or 25 to 35% by mass.

[0079] The photosensitive resin composition of this embodiment can be prepared by uniformly mixing the above-mentioned components using a roll mill, bead mill, or the like.

[0080] [Photosensitive element] The photosensitive element according to this embodiment comprises a support film and a photosensitive layer formed using the above-described photosensitive resin composition. Figure 1 is a schematic cross-sectional view showing the photosensitive element according to this embodiment. As shown in Figure 1, the photosensitive element 1 comprises a support film 10 and a photosensitive layer 20 formed on the support film 10.

[0081] The photosensitive element 1 can be manufactured by applying the photosensitive resin composition according to this embodiment onto a support film 10 using a known method such as reverse roll coating, gravure roll coating, comma coating, or curtain coating, and then drying the coating to form a photosensitive layer 20.

[0082] Examples of support films include polyester films such as polyethylene terephthalate and polybutylene terephthalate, and polyolefin films such as polypropylene and polyethylene. The thickness of the support film may be, for example, 5 to 100 μm. The surface roughness of the support film is not particularly limited, but the arithmetic mean roughness (Ra) may be 1000 nm or less, 500 nm or less, or 250 nm or less.

[0083] The thickness of the photosensitive layer may be, for example, 5 to 50 μm, 5 to 40 μm, or 10 to 30 μm.

[0084] The coating film can be dried using hot air drying, far-infrared radiation, or near-infrared radiation. The drying temperature may be 60-120°C, 70-110°C, or 80-100°C. The drying time may be 1-60 minutes, 2-30 minutes, or 5-20 minutes.

[0085] The photosensitive layer 20 may further include a protective film 30 covering the photosensitive layer 20. The photosensitive element 1 may also have the protective film 30 laminated on the side of the photosensitive layer 20 opposite to the side in contact with the support film 10. For example, a polymer film such as polyethylene or polypropylene may be used as the protective film 30.

[0086] [Printed Wiring Board] As shown in Figure 2, the printed wiring board according to this embodiment comprises a substrate 40, a first permanent resist layer 22 formed on the substrate 40, and a second permanent resist layer 24 formed on the first permanent resist layer 22. The second permanent resist layer contains a cured product of the photosensitive resin composition according to this embodiment and functions as a protruding dam that prevents the underfill from flowing out.

[0087] A first embodiment of a method for manufacturing a printed circuit board comprises the steps of: forming a first photosensitive layer on a substrate; exposing and developing the first photosensitive layer to form a first resist pattern on the substrate; forming a second photosensitive layer on the first resist pattern; exposing and developing the second photosensitive layer to form a second resist pattern on the first resist pattern; and curing the first resist pattern and the second resist pattern to form a first permanent resist layer and a second permanent resist layer. The following describes each step of manufacturing the printed circuit board according to this embodiment.

[0088] For example, a copper-clad laminate can be used as the substrate. The photosensitive layer can be formed using the above-mentioned photosensitive resin composition or photosensitive element. The photosensitive resin composition used to form the first photosensitive layer and the photosensitive resin composition used to form the second photosensitive layer may have the same composition or be different.

[0089] The photosensitive layer may be formed by coating a photosensitive resin composition onto a substrate and drying it. Examples of methods for coating the photosensitive resin composition include screen printing, spraying, roll coating, curtain coating, and electrostatic coating. The drying temperature may be 60 to 120°C, 70 to 110°C, or 80 to 100°C. The drying time may be 5 to 100 minutes, 10 to 90 minutes, or 15 to 60 minutes.

[0090] The photosensitive layer may be formed on a substrate by peeling off a protective film from a photosensitive element and laminating the photosensitive layer onto it. One method for laminating the photosensitive layer is to use a laminator for thermal lamination.

[0091] Next, the negative film is brought into direct contact with the photosensitive layer or into contact with it via a support film, and exposed by irradiation with active light. Examples of active light include electron beams, ultraviolet rays, and X-rays, with ultraviolet rays being preferred. As a light source, low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, halogen lamps, etc., can be used. The exposure amount is 10 to 2000 mJ / cm². ２ , 100-1500mJ / cm ２ , or 300-1000 mJ / cm ２ That's fine.

[0092] After exposure, the unexposed areas are removed with a developer to form a resist pattern. Examples of development methods include dipping and spraying. Suitable developers include alkaline aqueous solutions such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, and tetramethylammonium hydroxide.

[0093] A pattern-cured film (permanent resist) can be formed on a resist pattern by applying at least one of the following treatments: post-exposure and post-heating. The exposure dose for post-exposure is 100 to 5000 mJ / cm². ２ , 500-4000mJ / cm ２ , 800-3000mJ / cm ２ , or 1000-2500 J / cm ２ The heating temperature for the post-heating may be 120-200°C, 130-190°C, 140-180°C, or 150-175°C. The heating time for the post-heating may be 5 minutes to 12 hours, 10 minutes to 6 hours, 20 minutes to 3 hours, or 30 minutes to 2 hours.

[0094] In the first embodiment of the method for manufacturing the printed circuit board described above, the method may further include a step of post-exposing the first resist pattern after forming the first resist pattern but before forming the second photosensitive layer, or it may further include a step of post-exposing and post-heating the first resist pattern after forming the first resist pattern but before forming the second photosensitive layer. In the first embodiment, since the first photosensitive layer and the second photosensitive layer can be formed using the same photosensitive resin composition, the adhesion when forming the second photosensitive layer on the first resist pattern can be improved.

[0095] A second embodiment of the method for manufacturing a printed circuit board may include the steps of: forming a first photosensitive layer on a substrate and exposing the first photosensitive layer; forming a second photosensitive layer on the first photosensitive layer after exposure and exposing the second photosensitive layer; developing the first and second photosensitive layers after exposure to simultaneously form a first resist pattern and a second resist pattern on the substrate; and curing the first and second resist patterns to form a first permanent resist layer and a second permanent resist layer. In the second embodiment, the first and second photosensitive layers can be developed simultaneously, thus shortening the manufacturing process.

[0096] The permanent resist according to this embodiment can be used as a dam to prevent underfill leakage, an interlayer insulating layer or a surface protective layer for semiconductor elements. A semiconductor element having an interlayer insulating layer or surface protective layer formed from the cured film of the photosensitive resin composition described above, and an electronic device including the semiconductor element, can be manufactured. The semiconductor element may be, for example, a memory or package having a multilayer wiring structure, a rewiring structure, etc. Examples of electronic devices include mobile phones, smartphones, tablet terminals, personal computers, and hard disk suspensions. By providing a patterned cured film formed from the photosensitive resin composition according to this embodiment, highly reliable semiconductor elements and electronic devices can be provided.

[0097] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to these examples.

[0098] (A) The following acid-modified vinyl group-containing resins were prepared as component (A): A-1: ​​High-flexibility urethane-type acid-modified epoxy acrylate (acid value: 60 mg / KOH, Mw: 10000) A-2: Urethane-type acid-modified epoxy acrylate (acid value: 60 mg / KOH, Mw: 12000) A-3: Urethane-type acid-modified epoxy acrylate (acid value: 60 mg / KOH, Mw: 10000, manufactured by Nippon Kayaku Co., Ltd., product name "UXE-3024") A-4: Phenol novolac-type acid-modified epoxy acrylate (acid value: 60 mg / KOH, Mw: 7600, manufactured by Nippon Kayaku Co., Ltd., product name "PCR-1221H") A-5: Bisphenol F-type acid-modified epoxy acrylate (acid value: 98 mg / KOH, Mw: 15000, manufactured by Nippon Kayaku Co., Ltd., product name "ZFR-1401H")

[0099] Table 1 shows the acid value, weight-average molecular weight (Mw), and the value obtained by dividing Mw by the acid value for acid-modified vinyl group-containing resins.

[0100]

[0101] The following materials were prepared as components (B) to (G): B-1: Bisphenol F type epoxy resin (manufactured by Nippon Steel Chemical & Material Co., Ltd., trade name "YSLV-80XY") C-1: 2-methyl-[4-(methylthio)phenyl]morpholino-1-propanone (manufactured by IGM Resins B.V., trade name "Omnirad 907") C-2: 2,4-diethylthioxanthone (manufactured by Nippon Kayaku Co., Ltd., trade name "DETX-S") C-3: 4,4'-bis(diethylamino)benzophenone (EAB) C-4: Ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-,1-(O-acetyloxime) (manufactured by BASF Japan Ltd., trade name "Irgacure OXE02") D-1: Mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate (manufactured by Nippon Kayaku Co., Ltd., trade name "DPHA") E-1: Silica (manufactured by Denka Co., Ltd., trade name "SFP20M", average particle size: 0.3 μm) E-2: Barium sulfate (manufactured by Sakai Chemical Industry Co., Ltd., trade name "B-34") F-1: Phthalocyanine green (manufactured by Sanyo Shikkei Co., Ltd.) G-1: Epoxy-modified polybutadiene (manufactured by Daicel Corporation, trade name "PB-3600")

[0102] [Photosensitive resin composition] Each component was blended in the amounts (parts by mass, equivalent to solid content) shown in Table 2 or Table 3 and kneaded in a three-roll mill. Then, carbitol acetate was added to prepare the photosensitive resin composition so that the solid content concentration was 70% by mass.

[0103] [Photosensitive Element] A polyethylene terephthalate film with a thickness of 25 μm (manufactured by Toyobo Co., Ltd., product name "Toyobo Ester® Film G2 Series") was prepared as a support film. A solution of the photosensitive resin composition diluted with methyl ethyl ketone was applied to the support film so that the thickness after drying would be 25 μm, and the film was dried at 75°C for 30 minutes using a hot air convection dryer to form a photosensitive layer. Next, a polyethylene film (manufactured by Tamapoly Co., Ltd., product name "NF-15") was laminated as a protective film onto the surface opposite to the side of the photosensitive layer that is in contact with the support film to obtain a photosensitive element.

[0104] (Resolution) A copper-clad laminate substrate with a thickness of 0.6 mm (manufactured by Resonac Co., Ltd., product name "MCL-E-705G") was prepared. While peeling and removing the protective film from the photosensitive element, a photosensitive layer was laminated on the copper-clad laminate substrate using a press-type vacuum laminator (manufactured by Meiki Seisakusho Co., Ltd., product name "MVLP-500") to obtain a laminate. The lamination conditions were a vacuum evacuation time of 25 seconds, an air pressure of 4 kPa or less, a press hot plate temperature of 80 °C, a crimping pressure of 0.4 MPa, and a lamination press time of 25 seconds. After leaving the obtained laminate at room temperature for 30 minutes or more, exposure was performed using an i-line exposure apparatus (manufactured by Ushio Inc., product name "UX-2240SM") from above the support film of the laminate. The exposure pattern used a negative mask having an opening pattern of a predetermined size (opening diameter size: 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 150, 200 μm). The exposure was performed at an exposure amount at which the number of fully cured steps in a 41-step tablet was 10 steps. After exposure, after leaving it at room temperature for 30 minutes, the support film was peeled off from the photosensitive layer, and using a 1% by mass aqueous sodium carbonate solution at 30 °C, spraying development was performed at a pressure of 1.765×10 ５ Pa for 60 seconds to dissolve and develop the unexposed portions. Next, using an ultraviolet exposure apparatus, after exposing the developed photosensitive layer at an exposure amount of 2000 mJ / cm ２ a test piece having a cured film with an opening pattern of a predetermined size formed on the copper-clad laminate substrate was produced by heating at 170 °C for 1 hour. The above test piece was observed using an optical microscope and evaluated according to the following criteria. A: The minimum opening diameter size was 35 μm or less. B: The minimum opening diameter size exceeded 35 μm and was 55 μm or less. C: The minimum opening diameter size exceeded 55 μm.

[0105] (Resist Pattern Shape) The above test specimen was cast with embedding resin (using Mitsubishi Chemical Corporation's product name "jER828" as the epoxy resin and triethylenetetramine as the curing agent), and after sufficient curing, it was polished with a polishing machine (Refinetech Co., Ltd., product name "Refine Polisher") to remove the cross-section of the opening pattern of the cured film. The obtained cross-section of the opening pattern was observed using a metallurgical microscope. The resist pattern shape was evaluated according to the following criteria: A: No undercuts or missing parts on the top of the resist were observed, and the linearity of the pattern contour was good. B: Undercuts or missing parts on the top of the resist were observed, or the linearity of the pattern contour was poor.

[0106] (Solubility) A solution was obtained by dissolving 3 g of the photosensitive layer of the photosensitive element in 1 L of 1% by mass sodium carbonate aqueous solution. 30 mL of this solution was placed in a 50 mL screw-cap tube, capped, and left to stand in a 30°C constant temperature bath for 24 hours. The state of the solution in the screw-cap tube was visually checked. The solubility of the photosensitive layer in the developer was evaluated according to the following criteria: A: The solution was homogeneous. B: There was a small amount of solid matter adhering to the solution originating from the components of the photosensitive layer. C: There was a large amount of solid matter adhering to the solution originating from the components of the photosensitive layer.

[0107]

[0108]

[0109] (Example 9) A copper-clad laminate substrate with a thickness of 0.6 mm (manufactured by Resonac Co., Ltd., product name "MCL-E-705G") was prepared. While peeling off the protective film from the photosensitive element of Example 6, the photosensitive layer was laminated onto the copper-clad laminate substrate using a press-type vacuum laminator (manufactured by Meiki Seisakusho Co., Ltd., product name "MVLP-500") to laminate the first photosensitive layer and support film onto the copper-clad laminate substrate. The lamination conditions were: vacuuming time 25 seconds, atmospheric pressure 4 kPa or less, press hot plate temperature 80°C, pressing pressure 0.4 MPa, and lamination press time 25 seconds. After leaving the obtained laminate at room temperature for 30 minutes or more, exposure was performed on the support film of the laminate using an i-line exposure apparatus (manufactured by Ushio Inc., product name "UX-2240SM"). Using a negative mask without an aperture pattern, the first photosensitive layer was exposed at an exposure level that resulted in 10 fully cured steps in a 41-step tablet. Then, the support film was peeled off the first photosensitive layer, and the photosensitive layer was treated with a 1% by mass sodium carbonate aqueous solution for 60 seconds at a rate of 1.765 × 10⁻⁶. ５ A laminated substrate A was fabricated by spray developing with Pa pressure to remove unexposed areas and form a first resist pattern.

[0110] On laminated substrate A, the photosensitive layer of the photosensitive element of Example 6 was laminated in the same manner as described above to form a second photosensitive layer and a support film. After leaving the resulting laminate at room temperature for 30 minutes or more, the second photosensitive layer was exposed from above the support film of the laminate using an i-line exposure apparatus (Ushio Inc., product name "UX-2240SM"). The exposure pattern used was a negative mask having a predetermined size of protruding dam-forming pattern (aperture diameter sizes: 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 150, 200 μm). The exposure was performed at an exposure amount that resulted in 10 complete curing steps in a 41-step tablet. After exposure, after leaving at room temperature for 30 minutes, the support film was peeled off from the second photosensitive layer, and 1.765 × 10⁻¹⁶ of a 1% by mass aqueous sodium carbonate solution at 30°C was used for 60 seconds. ５ The first and second resist patterns were spray-developed at a pressure of Pa to remove unexposed areas and form a second resist pattern. Next, the first and second resist patterns were exposed to ultraviolet light at 2000 mJ / cm using an ultraviolet exposure apparatus.２ After post-exposure with the specified exposure dose, a test substrate was prepared by heating at 170°C for 1 hour, in which a cured film of the first resist pattern and a cured film of the second resist pattern were formed in that order on a copper-clad laminated substrate.

[0111] (Example 10) The first resist pattern on the laminated substrate A was exposed to ultraviolet light at 2000 mJ / cm using an ultraviolet exposure apparatus. ２ A laminated substrate B was fabricated by post-exposure with the specified exposure dose. A second resist pattern was formed in the same manner as in Example 9, except that laminated substrate B was used. Next, the second resist pattern was exposed to ultraviolet light at 2000 mJ / cm using an ultraviolet exposure apparatus. ２ After post-exposure with the specified exposure dose, a test substrate was prepared by heating at 170°C for 1 hour, in which a cured film of the first resist pattern and a cured film of the second resist pattern were formed in that order on a copper-clad laminated substrate.

[0112] (Example 11) The first resist pattern on the laminated substrate A was exposed to ultraviolet light at 2000 mJ / cm using an ultraviolet exposure apparatus. ２ After post-exposure with the specified exposure dose, the laminated substrate C was fabricated by heating at 170°C for 1 hour. A second resist pattern was formed in the same manner as in Example 9, except that laminated substrate C was used. Next, the second resist pattern was exposed to ultraviolet light at 2000 mJ / cm² using an ultraviolet exposure apparatus. ２ After post-exposure with the specified exposure dose, a test substrate was prepared by heating at 170°C for 1 hour, in which a cured film of the first resist pattern and a cured film of the second resist pattern were formed in that order on a copper-clad laminated substrate.

[0113] (Example 12) Using the photosensitive element of Example 6, the first photosensitive layer and support film were laminated on a copper-clad laminate (MCL-E-705G) in the same procedure as in Example 9. After leaving the resulting laminate at room temperature for 30 minutes or more, the first photosensitive layer was exposed in the same procedure as in Example 9. Subsequently, a laminated substrate D was prepared by peeling the support film off the first photosensitive layer.

[0114] On the laminated substrate D, the photosensitive layer of the photosensitive element of Example 6 was laminated in the same manner as described above to form the second photosensitive layer and support film. After leaving the resulting laminate at room temperature for 30 minutes or more, the second photosensitive layer was exposed using the same procedure as in Example 9. Subsequently, the first and second photosensitive layers were developed to simultaneously form the first and second resist patterns. Next, the first and second resist patterns were exposed to ultraviolet light at 2000 mJ / cm² using an ultraviolet exposure apparatus. ２ After post-exposure with the specified exposure dose, a test substrate was prepared by heating at 170°C for 1 hour, in which a cured film of the first resist pattern and a cured film of the second resist pattern were formed in that order on a copper-clad laminated substrate.

[0115] (Examples 13-16) Test substrates were prepared in the same manner as in Examples 9-12, except that the photosensitive element of Example 8 was used.

[0116] (Evaluation) Each test substrate of Examples 9 to 16 was observed using an optical microscope, and it was confirmed that a protruding dam formed by the cured film of the second resist pattern was formed on the cured film of the first resist pattern, and that there was no development residue of the second resist pattern on the cured film of the first resist pattern.

[0117] 1...Photosensitive element, 10...Support film, 20...Photosensitive layer, 22...First permanent resist layer, 24...Second permanent resist layer, 30...Protective film, 40...Substrate.

Claims

1. A method for manufacturing a printed circuit board, comprising the steps of: forming a first photosensitive layer on a substrate; exposing and developing the first photosensitive layer to form a first resist pattern on the substrate; forming a second photosensitive layer on the first resist pattern; exposing and developing the second photosensitive layer to form a second resist pattern on the first resist pattern; and curing the first resist pattern and the second resist pattern to form a first permanent resist layer and a second permanent resist layer, wherein the second permanent resist layer is a protruding dam for preventing underfill leakage.

2. The method for manufacturing a printed circuit board according to claim 1, further comprising the step of post-exposing the first resist pattern after forming the first resist pattern and before forming the second photosensitive layer.

3. The method for manufacturing a printed circuit board according to claim 1, further comprising the step of post-exposing and post-heating the first resist pattern after forming the first resist pattern and before forming the second photosensitive layer.

4. A method for manufacturing a printed circuit board, comprising the steps of: forming a first photosensitive layer on a substrate and exposing the first photosensitive layer; forming a second photosensitive layer on the first photosensitive layer after exposure and exposing the second photosensitive layer; developing the first and second photosensitive layers after exposure to simultaneously form a first resist pattern and a second resist pattern on the substrate; and curing the first and second resist patterns to form a first permanent resist layer and a second permanent resist layer, wherein the second permanent resist layer is a protruding dam for preventing underfill leakage.

5. A method for manufacturing a printed circuit board according to any one of claims 1 to 4, wherein the second permanent resist layer comprises a cured product of a photosensitive resin composition containing (A) an acid-modified vinyl group-containing resin, (B) a thermosetting resin, (C) a photopolymerizable compound, and (D) a photopolymerization initiator, and the (A) acid-modified vinyl group-containing resin comprises one type of acid-modified vinyl group-containing resin, or two or more types of acid-modified vinyl group-containing resins, and the difference in the values ​​obtained by dividing the weight-average molecular weight of each of the two or more acid-modified vinyl group-containing resins by their acid value is 30 or less.

6. The method for manufacturing a printed circuit board according to claim 5, wherein the (A) acid-modified vinyl group-containing resin comprises two or more acid-modified vinyl group-containing resins, and the difference between the values ​​obtained by dividing the weight-average molecular weight of each of the two or more acid-modified vinyl group-containing resins by their acid value is 30 or less.

7. The method for manufacturing a printed circuit board according to claim 6, wherein the (A) acid-modified vinyl group-containing resin comprises two or more selected from the group consisting of urethane-type acid-modified epoxy (meth)acrylate, phenol novolac-type acid-modified epoxy (meth)acrylate, and bisphenol-type acid-modified epoxy (meth)acrylate.

8. The method for manufacturing a printed circuit board according to claim 5, wherein the photosensitive resin composition further contains (E) an inorganic filler.

9. The method for manufacturing a printed circuit board according to claim 5, wherein the photosensitive resin composition further contains (F) a pigment.

10. The method for manufacturing a printed circuit board according to claim 5, wherein the photosensitive resin composition further contains (G) an elastomer.

11. A photosensitive resin composition for forming a dam to prevent underfill outflow, comprising (A) an acid-modified vinyl group-containing resin, (B) a thermosetting resin, (C) a photopolymerizable compound, and (D) a photopolymerization initiator, wherein the (A) acid-modified vinyl group-containing resin comprises one type of acid-modified vinyl group-containing resin, or two or more types of acid-modified vinyl group-containing resins, and the difference in the values ​​obtained by dividing the weight-average molecular weight of each of the two or more acid-modified vinyl group-containing resins by their acid value is 30 or less.

12. The photosensitive resin composition according to claim 11, wherein the (A) acid-modified vinyl group-containing resin comprises two or more acid-modified vinyl group-containing resins, and the difference between the values ​​obtained by dividing the weight-average molecular weight of each of the two or more acid-modified vinyl group-containing resins by their acid value is 30 or less.

13. The photosensitive resin composition according to claim 12, wherein the (A) acid-modified vinyl group-containing resin comprises two or more selected from the group consisting of urethane-type acid-modified epoxy (meth)acrylate, phenol novolac-type acid-modified epoxy (meth)acrylate, and bisphenol-type acid-modified epoxy (meth)acrylate.

14. (E) The photosensitive resin composition according to claim 11, further comprising an inorganic filler.

15. (F) The photosensitive resin composition according to claim 11, further comprising a pigment.

16. (G) The photosensitive resin composition according to claim 11, further comprising an elastomer.

17. A photosensitive element comprising a support film and a photosensitive layer formed on the support film using the photosensitive resin composition described in any one of claims 11 to 16.

18. A printed circuit board comprising a substrate, a first permanent resist layer formed on the substrate, and a second permanent resist layer formed on the first permanent resist layer, wherein the second permanent resist layer is a protruding dam that prevents underfill from flowing out, and the printed circuit board includes a cured product of the photosensitive resin composition according to any one of claims 11 to 16.

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