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

Abstract

To provide a photosensitive resin composition capable of forming a permanent resist having good crack resistance and excellent insulation reliability.SOLUTION: The photosensitive resin composition contains (A) an acid-modified vinyl group-containing resin, (B) a thermosetting resin, (C) a photopolymerizable compound, (D) a photopolymerization initiator and (E) a secondary thiol compound.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a photosensitive resin composition, a photosensitive element, a printed wiring board, and a method for producing a printed wiring board. [Background technology]

[0002] In the field of printed wiring boards, permanent resists are formed on printed wiring boards. The permanent resists have the role of preventing corrosion of the conductor layers and maintaining electrical insulation between the conductor layers when the printed wiring board is in use. In recent years, permanent resists have also come to function as solder resist films that prevent solder from adhering to unnecessary portions of the conductor layers of the printed wiring board in processes such as flip-chip mounting and wire bonding mounting of semiconductor elements on the printed wiring board via solder.

[0003] Conventionally, permanent resists have been produced by screen printing using a thermosetting resin composition or by a photographic method using a photosensitive resin composition. For example, in flexible wiring boards using mounting methods such as FC (Flip Chip), TAB (Tape Automated Bonding), and COF (Chip On Film), a thermosetting resin paste is screen printed and thermally cured to form a permanent resist, except for the IC chip, electronic components, or LCD (Liquid Crystal Display) panel and connection wiring pattern area (see, for example, Patent Document 1).

[0004] In semiconductor package substrates such as BGA (ball grid array) and CSP (chip size package) mounted on electronic components, it is necessary to remove the permanent resist from the bonding area in order to (1) flip-chip mount a semiconductor element onto the semiconductor package substrate via solder, (2) wire-bond the semiconductor element to the semiconductor package substrate, and (3) solder-bond the semiconductor package substrate to a motherboard. A photographic method is used to form an image on the permanent resist. This method involves applying a photosensitive resin composition, drying it, and then selectively irradiating it with actinic rays such as ultraviolet light to harden it, and then removing only the unirradiated areas by development to form an image. Because the photographic method is easy to work with and suitable for mass production, it is widely used in the electronic materials industry for forming images on photosensitive materials (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-198105 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-133851 Summary of the Invention [Problem to be solved by the invention]

[0006] In response to the increasing density of printed wiring boards, even higher performance is being demanded of permanent resists (solder resists). In particular, requirements for crack resistance and insulation reliability are increasing year by year, making it important to achieve a high level of compatibility between these properties. However, permanent resists formed from conventional photosensitive resin compositions have the problem of being prone to cracking when subjected to thermal cycle testing. Furthermore, permanent resists formed from conventional photosensitive resin compositions may experience short circuits due to migration in less than 200 hours of testing in HAST (Highly Accelerated Stress Test), an insulation reliability evaluation, when the line width / space width is 10 μm / 10 μm.

[0007] The present disclosure aims to provide a photosensitive resin composition capable of forming a permanent resist having good crack resistance and excellent insulation reliability, a photosensitive element using the photosensitive resin composition, a printed wiring board, and a method for producing a printed wiring board. [Means for solving the problem]

[0008] In order to solve the above problems, the present disclosure provides the following photosensitive resin composition, photosensitive element, printed wiring board, and method for producing a printed wiring board.

[0009] [1] A photosensitive resin composition containing (A) an acid-modified vinyl group-containing resin, (B) a thermosetting resin, (C) a photopolymerizable compound, (D) a photopolymerization initiator, and (E) a secondary thiol compound. [2] The photosensitive resin composition according to [1] above, wherein the content of the component (E) is 0.05 mass % or more based on the total solid content of the photosensitive resin composition. [3] The photosensitive resin composition according to [1] or [2] above, wherein the content of the component (E) is 0.05 to 3.0 mass % based on the total solid content of the photosensitive resin composition. [4] The photosensitive resin composition according to any one of the above [1] to [3], wherein the component (E) has 2 to 6 functional groups. [5] The photosensitive resin composition according to any one of [1] to [4] above, wherein the component (B) comprises a first multifunctional epoxy resin having a molecular weight of less than 380 and a second multifunctional epoxy resin having a molecular weight of 380 or more. [6] The photosensitive resin composition according to [5] above, wherein the mass ratio of the content of the component (E) to the content of the second multifunctional epoxy resin is 0.005 to 0.5. [7] The photosensitive resin composition according to any one of the above [1] to [6], further comprising (F) an inorganic filler. [8] The photosensitive resin composition according to any one of the above [1] to [7], further comprising (G) a photosensitizer. [9] The photosensitive resin composition according to any one of the above [1] to [8], further comprising (H) an elastomer.

[10] A photosensitive element comprising a support film and a photosensitive layer formed on the support film, wherein the photosensitive layer contains the photosensitive resin composition according to any one of [1] to [9] above.

[11] A printed wiring board comprising a permanent resist containing a cured product of the photosensitive resin composition according to any one of [1] to [9] above.

[12] A method for producing a printed wiring board, comprising the steps of: forming a photosensitive layer on a substrate using the photosensitive resin composition according to any one of [1] to [9] above; exposing and developing the photosensitive layer to form a resist pattern; and curing the resist pattern to form a permanent resist.

[13] A method for manufacturing a printed wiring board, comprising the steps of: forming a photosensitive layer on a substrate using the photosensitive element described in

[10] above; exposing and developing the photosensitive layer to form a resist pattern; and curing the resist pattern to form a permanent resist. [Effects of the Invention]

[0010] According to the present disclosure, it is possible to provide a photosensitive resin composition capable of forming a permanent resist having good crack resistance and excellent insulation reliability, a photosensitive element using the photosensitive resin composition, a printed wiring board, and a method for producing a printed wiring board. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view schematically illustrating a photosensitive element according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present disclosure will be described in detail below. In this specification, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes as long as the intended function of the process is achieved. The term "layer" encompasses not only a structure that is formed over the entire surface when observed in a plan view, but also a structure that is formed only on a portion of the surface. A numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In numerical ranges described in stages in this specification, the upper or lower limit of a numerical range of a certain stage may be replaced with the upper or lower limit of a numerical range of another stage. In numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with a value shown in the examples.

[0013] When referring to the amount of each component in a composition in this specification, if there are multiple substances corresponding to each component in the composition, the total amount of those multiple substances present in the composition is meant unless otherwise specified.

[0014] In this specification, "(meth)acrylate" means at least one of "acrylate" and its corresponding "methacrylate," and the same applies to other similar expressions such as (meth)acrylic acid and (meth)acryloyl. In this specification, "solid content" refers to the non-volatile content excluding volatile substances (water, solvent, etc.) contained in the photosensitive resin composition, and includes components that are liquid, syrup-like, or waxy at room temperature (around 25°C).

[0015] [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 photopolymerizable compound, (D) a photopolymerization initiator, and (E) a secondary thiol compound. The photosensitive resin composition according to this embodiment is a negative-type photosensitive resin composition, and a cured film of the photosensitive resin composition can be suitably used as a permanent resist. Each component used in the photosensitive resin composition according to this embodiment will be described in more detail below.

[0016] (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). The acid-modified vinyl group-containing resin is not particularly limited as long as it has a vinyl bond, which is a photopolymerizable ethylenically unsaturated bond, and an alkali-soluble acidic group.

[0017] Examples of the group having an ethylenically unsaturated bond contained in component (A) include a vinyl group, an allyl group, a propargyl group, a butenyl group, an ethynyl group, a phenylethynyl group, a maleimide group, a nadimide group, and a (meth)acryloyl group. Among these, from the viewpoints of reactivity and resolution, a (meth)acryloyl group is preferred. Examples of the acidic group contained in component (A) include a carboxy group, a sulfo group, and a phenolic hydroxyl group. Among these, from the viewpoint of resolution, a carboxy group is preferred.

[0018] The component (A) is preferably an acid-modified vinyl group-containing epoxy derivative obtained by reacting (c) a saturated or unsaturated group-containing polybasic acid anhydride (hereinafter sometimes referred to as the component (c)) with a resin (A') obtained by reacting (a) an epoxy resin (hereinafter sometimes referred to as the component (a)) with (b) an ethylenically unsaturated group-containing organic acid (hereinafter sometimes referred to as the component (b)).

[0019] Examples of acid-modified vinyl group-containing epoxy derivatives include acid-modified epoxy(meth)acrylates. Acid-modified epoxy(meth)acrylates are resins obtained by acid-modifying epoxy(meth)acrylate, which is a reaction product of components (a) and (b), with component (c). Examples of acid-modified epoxy(meth)acrylates include addition reaction products obtained by adding saturated or unsaturated polybasic acid anhydrides to esters obtained by reacting epoxy resins with vinyl group-containing monocarboxylic acids.

[0020] Examples of the component (A) include an acid-modified vinyl group-containing resin (A1) (hereinafter, sometimes referred to as the “component (A1)”) obtained by using a bisphenol novolac epoxy resin (a1) (hereinafter, sometimes referred to as the “epoxy resin (a1)”) as the component (a), and an acid-modified vinyl group-containing resin (A2) (hereinafter, sometimes referred to as the “component (A2)”) obtained by using an epoxy resin (a2) (hereinafter, sometimes referred to as the “epoxy resin (a2)”) other than the epoxy resin (a1) as the component (a).

[0021] Examples of the epoxy resin (a1) include epoxy resins having a structural unit represented by the following formula (I) or (II).

[0022] [ka]

[0023] In formula (I), R 11 represents a hydrogen atom or a methyl group, and multiple R 11 may be the same or different. Y 1 and Y 2 each independently represents a hydrogen atom or a glycidyl group, and Y 1 and Y 2 At least one of R is a glycidyl group. From the viewpoint of suppressing undercut and improving the linearity and resolution of the resist pattern contour, 11 is preferably a hydrogen atom, and from the viewpoint of further improving thermal shock resistance, Y 1 and Y 2 is preferably a glycidyl group.

[0024] The number of structural units represented by formula (I) in the epoxy resin (a1) is 1 or more, and may be 10 to 100, 15 to 80, or 15 to 70. When the number of structural units is within the above range, it is easy to improve the linearity of the resist pattern contour, adhesion to the copper substrate, heat resistance, and electrical insulation. Here, the number of structural units of a structural unit is an integer value in a single molecule, and is a rational number that is an average value in an aggregate of multiple types of molecules. The same applies to the number of structural units of a structural unit hereinafter.

[0025] [ka]

[0026] In formula (II), R 12 represents a hydrogen atom or a methyl group, and multiple R 12 may be the same or different. Y 3 and Y 4 each independently represents a hydrogen atom or a glycidyl group, and Y 3 and Y 4 At least one of R is a glycidyl group. From the viewpoint of suppressing undercut and improving the linearity and resolution of the resist pattern contour, 12 is preferably a hydrogen atom, and from the viewpoint of further improving thermal shock resistance, Y 3 and Y 4 is preferably a glycidyl group.

[0027] The number of structural units represented by formula (II) in the epoxy resin (a1) is 1 or more, and may be 10 to 100, 15 to 80, or 15 to 70. When the number of structural units is within the above range, it becomes easier to improve the linearity of the resist pattern contour, adhesion to a copper substrate, and heat resistance.

[0028] In formula (II), R 12 is a hydrogen atom, and Y 3 and Y 4 The epoxy resins in which R is a glycidyl group are available as EXA-7376 series (manufactured by DIC Corporation, trade name), and R 12 is a methyl group, and Y 3 and Y4 Epoxy resins in which the carboxyl group is a glycidyl group are commercially available as the EPON SU8 series (trade name, manufactured by Westlake).

[0029] The epoxy resin (a2) is not particularly limited as long as it is an epoxy resin different from the epoxy resin (a1). However, from the viewpoints of suppressing the occurrence of undercut and improving the linearity of the resist pattern contour, adhesion to the copper substrate, and resolution, it is preferable that the epoxy resin (a2) be at least one selected from the group consisting of novolac-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, triphenolmethane-type epoxy resins, and biphenyl-type epoxy resins.

[0030] Examples of novolac-type epoxy resins include epoxy resins having a structural unit represented by the following formula (III). Examples of bisphenol A-type epoxy resins or bisphenol F-type epoxy resins include epoxy resins having a structural unit represented by the following formula (IV). Examples of triphenolmethane-type epoxy resins include epoxy resins having a structural unit represented by the following formula (V). Examples of biphenyl-type epoxy resins include epoxy resins having a structural unit represented by the following formula (VI).

[0031] The epoxy resin (a2) is preferably a novolac epoxy resin having a structural unit represented by the following formula (III): An example of a novolac epoxy resin having such a structural unit is a novolac epoxy resin represented by the following formula (III'):

[0032] [ka]

[0033] In formulas (III) and (III'), R 13 represents a hydrogen atom or a methyl group, and Y 5 represents a hydrogen atom or a glycidyl group, and Y 5In formula (III'), n1 is a number of 1 or more, and at least one of R 13 and Y 5 From the viewpoint of suppressing the occurrence of undercut and improving the linearity and resolution of the resist pattern contour, R 13 is preferably a hydrogen atom.

[0034] In formula (III'), Y is a hydrogen atom. 5 and a glycidyl group, Y 5 From the viewpoint of suppressing the occurrence of undercut and improving the linearity and resolution of the resist pattern contour, the molar ratio of n1 to n2 may be 0 / 100 to 30 / 70 or 0 / 100 to 10 / 90. n1 is 1 or more, but may also be 10 to 200, 30 to 150, or 30 to 100. When n1 is within the above range, the linearity of the resist pattern contour, adhesion to a copper substrate, and heat resistance are likely to be improved.

[0035] Examples of the novolac epoxy resin represented by formula (III') include phenol novolac epoxy resin and cresol novolac epoxy resin. These novolac epoxy resins can be obtained, for example, by reacting a phenol novolac resin or a cresol novolac resin with epichlorohydrin using a known method.

[0036] Commercially available examples of the phenol novolac epoxy resin or cresol novolac epoxy resin represented by formula (III') include YDCN-700-7, YDCN-700-10, YDCN-704, YDCN-704A, and YDPN-638 (all of which are product names manufactured by Nippon Steel Chemical & Material Co., Ltd.), EOCN-102S, EOCN-103S, EOCN-104S, EOCN-1012, EOCN-1027, and BREN-S (all of which are product names manufactured by Nippon Kayaku Co., Ltd.), and N-740, N-770, N-665, and N-673 (all of which are product names manufactured by DIC Corporation).

[0037] Preferred examples of the epoxy resin (a2) include bisphenol A-type epoxy resins or bisphenol F-type epoxy resins having a structural unit represented by the following formula (IV): Epoxy resins having such a structural unit include, for example, bisphenol A-type epoxy resins or bisphenol F-type epoxy resins represented by the following formula (IV'):

[0038] [ka]

[0039] In formulas (IV) and (IV'), R 14 represents a hydrogen atom or a methyl group, and there are multiple R 14 may be the same or different, and Y 6 represents a hydrogen atom or a glycidyl group. In formula (IV'), n2 represents a number of 1 or more, and when n2 is 2 or more, a plurality of Y 6 may be the same or different, and at least one Y 6 is a glycidyl group.

[0040] From the viewpoint of suppressing the occurrence of undercut and improving the linearity and resolution of the resist pattern contour, R 14 is preferably a hydrogen atom, and from the viewpoint of further improving thermal shock resistance, Y 6 is preferably a glycidyl group. n2 is 1 or greater, but may be 10 to 100, 10 to 80, or 15 to 60. When n2 is within the above range, the linearity of the resist pattern contour, adhesion to the copper substrate, and heat resistance are likely to be improved.

[0041] Y in formula (IV) 6 The bisphenol A type epoxy resin or bisphenol F type epoxy resin in which Y is a glycidyl group can be prepared by, for example, 6 is a hydrogen atom, the hydroxyl group (-OY 6 ) with epichlorohydrin.

[0042] Commercially available examples of the bisphenol A epoxy resin or bisphenol F epoxy resin represented by formula (IV') include jER807, jER825, jER827, jER828, jER834, jER1004F, jER1007FS, and jER1009F (all of which are product names manufactured by Mitsubishi Chemical Corporation), YD-8125, YDF-170, YDF-2001, YDF-2004, and YDF-8170C (all of which are product names manufactured by Nippon Steel Chemical & Material Co., Ltd.), and the like.

[0043] The epoxy resin (a2) is preferably a triphenolmethane-type epoxy resin having a structural unit represented by the following formula (V): An example of a triphenolmethane-type epoxy resin having such a structural unit is a triphenolmethane-type epoxy resin represented by the following formula (V'):

[0044] [ka]

[0045] In formulas (V) and (V'), Y 7 represents a hydrogen atom or a glycidyl group, and a plurality of Y 7 may be the same or different, and at least one Y 7 is a glycidyl group. In formula (V'), n3 is a number of 1 or more.

[0046] From the viewpoint of suppressing the occurrence of undercut and upper portion loss and improving the linearity and resolution of the resist pattern contour, Y 7 Y is a hydrogen atom in 7 and a glycidyl group, Y 7 The molar ratio of Y to Y may be 0 / 100 to 30 / 70. 7 At least one of these is a glycidyl group. n3 is 1 or greater, and may be 10 to 100, 15 to 80, or 15 to 70. When n3 is within the above range, the linearity of the resist pattern contour, adhesion to the copper substrate, and heat resistance are likely to be improved.

[0047] As the triphenolmethane type epoxy resin represented by formula (V'), for example, FAE-2500, EPPN-501H, EPPN-502H (all of which are trade names manufactured by Nippon Kayaku Co., Ltd.) and the like are commercially available.

[0048] The epoxy resin (a2) is preferably a biphenyl-type epoxy resin having a structural unit represented by the following formula (VI): An example of a biphenyl-type epoxy resin having such a structural unit is a biphenyl-type epoxy resin represented by the following formula (VI'):

[0049] [ka]

[0050] In formulas (VI) and (VI'), Y 8 represents a hydrogen atom or a glycidyl group, and a plurality of Y 8 may be the same or different, and at least one Y 8 is a glycidyl group. In formula (V'), n4 is a number of 1 or more.

[0051] As the biphenyl type epoxy resin represented by formula (VI'), for example, NC-3000, NC-3000-L, NC-3000-H, NC-3000-FH-75M (all of which are trade names manufactured by Nippon Kayaku Co., Ltd.) and the like are commercially available.

[0052] The epoxy resin (a2) is preferably at least one selected from the group consisting of novolac epoxy resins having a structural unit represented by formula (III), bisphenol A epoxy resins having a structural unit represented by formula (IV), and bisphenol F epoxy resins having a structural unit represented by formula (IV), and more preferably bisphenol F epoxy resins having a structural unit represented by formula (IV).

[0053] From the viewpoint of further improving thermal shock resistance, warpage reduction, and resolution, a component (A1) using a bisphenol novolac epoxy resin having a structural unit represented by formula (II) as the epoxy resin (a1) and a component (A2) using a bisphenol A epoxy resin or bisphenol F epoxy resin having a structural unit represented by formula (IV) as the epoxy resin (a2) may be used in combination.

[0054] Examples of component (b) include acrylic acid, acrylic acid dimers, methacrylic acid, acrylic acid derivatives such as β-furfurylacrylic acid, β-styrylacrylic acid, cinnamic acid, crotonic acid, and α-cyanocinnamic acid; half-ester compounds which are reaction products of hydroxyl group-containing (meth)acrylates and dibasic acid anhydrides; and half-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 singly or in combination of two or more.

[0055] The half-ester compound 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.

[0056] 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, trimethylolpropane di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and glycidyl (meth)acrylate.

[0057] 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.

[0058] In the reaction between component (a) and component (b), the ratio of component (b) is preferably 0.6 to 1.05 equivalents, and more preferably 0.8 to 1.0 equivalents, of component (b) per equivalent of epoxy groups in component (a). Reaction at such a ratio tends to increase photosensitivity and result in excellent linearity of the resist pattern contour.

[0059] A polymerization inhibitor may be used in the reaction between component (a) and component (b) to prevent polymerization during the reaction. Examples of polymerization inhibitors include hydroquinone, methylhydroquinone, hydroquinone monomethyl ether, catechol, and pyrogallol. One type of polymerization inhibitor may be used alone, or two or more types may be used in combination.

[0060] From the viewpoint of improving stability, the amount of the polymerization inhibitor used may be 0.01 to 1 part by mass, 0.02 to 0.8 parts by mass, or 0.04 to 0.5 parts by mass per 100 parts by mass of the total of the components (a) and (b).

[0061] Component (A'), obtained by reacting components (a) and (b), has hydroxyl groups formed by a ring-opening addition reaction between the epoxy groups of component (a) and the carboxyl groups 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 groups of component (c) are half-esterified.

[0062] 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.

[0063] In the reaction between component (A') and component (c), for example, the acid value of component (A) can be adjusted by reacting 0.1 to 1.0 equivalents of component (c) with 1 equivalent of hydroxyl groups in component (A').

[0064] If necessary, a hydrogenated bisphenol A type epoxy resin may be used in part as component (a), or a styrene-maleic acid resin such as a hydroxyethyl (meth)acrylate modified styrene-maleic anhydride copolymer may be used in part.

[0065] From the viewpoints of suppressing the occurrence of undercuts and further improving adhesion to the copper substrate, thermal shock resistance, and resolution, the component (A) preferably contains the component (A1), and from the viewpoint of particularly improving adhesion strength, it is more preferable for the component (A) to contain the component (A1) and the component (A2).

[0066] When the component (A1) and the component (A2) are used in combination as the component (A), the mass ratio of (A1) / (A2) is not particularly limited, but may be 20 / 80 to 90 / 10, 30 / 70 to 80 / 20, 40 / 60 to 75 / 25, or 50 / 50 to 70 / 30 from the viewpoint of improving the linearity of the resist pattern contour, the electroless plating resistance, and the heat resistance.

[0067] The acid value of component (A) is not particularly limited. From the viewpoint of improving the solubility of the unexposed area in an alkaline aqueous solution, the acid value of component (A) may be 30 mgKOH / g or more, 40 mgKOH / g or more, or 50 mgKOH / g or more. From the viewpoint of improving the electrical properties of the cured film, the acid value of component (A) may be 150 mgKOH / g or less, 120 mgKOH / g or less, or 100 mgKOH / g or less.

[0068] The weight-average molecular weight (Mw) of component (A) is not particularly limited. From the viewpoint of improving the adhesion of the cured film, Mw of component (A) may be 3,000 or more, 4,000 or more, or 5,000 or more. From the viewpoint of improving the resolution of the photosensitive layer, Mw of component (A) may be 30,000 or less, 25,000 or less, or 18,000 or less.

[0069] Mw can be measured by gel permeation chromatography (GPC). Mw can be measured, for example, under the following GPC conditions, and the value converted using a calibration curve of standard polystyrene can be used as Mw. The calibration curve can be created using a five-sample set ("PStQuick MP-H" and "PStQuick B", manufactured by Tosoh Corporation) as standard polystyrene. GPC equipment: High-speed GPC equipment "HCL-8320GPC" (Tosoh Corporation) Detector: Differential refractometer or UV detector (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℃ Flow rate: 0.35mL / min Sample concentration: 10 mg / 5 mL of THF Injection volume: 20μL

[0070] The content of the component (A) in the photosensitive resin composition may be 20 to 70 mass%, 25 to 60 mass%, or 30 to 50 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.

[0071] ((B) component: thermosetting resin) The photosensitive resin composition according to this embodiment uses a thermosetting resin as component (B), which can improve the heat resistance, adhesiveness, and chemical resistance of a cured film (permanent resist) formed from the photosensitive resin composition. The component (B) may be used alone or in combination of two or more.

[0072] 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.

[0073] Examples of epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, hydrogenated bisphenol A type epoxy resins, brominated bisphenol A type epoxy resins, bisphenol S type epoxy resins, novolac type epoxy resins, biphenyl type epoxy resins, naphthalene type epoxy resins, dicyclopentadiene type epoxy resins, hydantoin type epoxy resins, triglycidyl isocyanurate, and bixylenol type epoxy resins.

[0074] The (B) component preferably contains a first multifunctional epoxy resin (B1) (hereinafter sometimes referred to as "component (B1)") having a molecular weight of less than 380 and a second multifunctional epoxy resin (B2) (hereinafter sometimes referred to as "component (B2)") having a molecular weight of 380 or more. When the (B) component contains the (B1) component, developability tends to be improved. When the (B) component contains the (B2) component, insulation reliability is improved, but developability tends to be deteriorated. Therefore, by using two types of multifunctional epoxy resins, the (B1) component and the (B2) component, in combination, developability tends to be maintained and insulation reliability tends to be improved. The (B1) component may be used alone, or two or more types may be used in combination. The (B2) component may be used alone, or two or more types may be used in combination.

[0075] To obtain the above effects more fully, the molecular weight of the (B1) component may be 100 or more and less than 380, or 200 or more and less than 380, and the molecular weight of the (B2) component may be 380-1000, or 380-500.

[0076] The contents of the components (B1) and (B2) in the component (B) are not particularly limited, but from the viewpoint of improving developability, the mass ratio of the content of the component (B1) to the content of the component (B2) (content of the component (B1) / content of the component (B2)) may be 1.0 to 5.0, or 1.0 to 3.0.

[0077] The mass ratio of the content of component (E) to the content of component (B2) (content of component (E) / content of component (B2)) may be 0.005 to 0.5, or 0.008 to 0.4. By keeping the mass ratio of component (B2) to component (E) within the above range, component (B2) and component (E) tend to react to form a crosslinked structure, which tends to improve crack resistance and insulation reliability.

[0078] The content of component (B) may be 2 to 30 mass%, 5 to 25 mass%, or 8 to 20 mass%, based on the total solid content of the photosensitive resin composition. When the content of component (B) is within the above range, good developability can be maintained while the heat resistance of the formed cured film can be further improved.

[0079] ((C) component: photopolymerizable compound) The component (C) is not particularly limited as long as it is a compound having a functional group exhibiting photopolymerizability. The component (C) may be a photopolymerizable compound having an ethylenically unsaturated group but not an acidic group. The component (C) preferably includes at least one selected from the group consisting of (Ci) a monofunctional vinyl monomer having one polymerizable ethylenically unsaturated group, (Cii) a bifunctional vinyl monomer having two polymerizable ethylenically unsaturated groups, and (Ciii) a multifunctional vinyl monomer having at least three polymerizable ethylenically unsaturated groups, and more preferably includes at least the component (Ciii). The components (Ci) to (Ciii) preferably have a molecular weight of 1,000 or less.

[0080] ((Ci) Monofunctional vinyl monomer) Examples of the monofunctional vinyl monomer having one polymerizable ethylenically unsaturated group include (meth)acrylic acid and (meth)acrylic acid alkyl esters. Examples of the (meth)acrylic acid alkyl esters include (meth)acrylic acid methyl ester, (meth)acrylic acid ethyl ester, (meth)acrylic acid butyl ester, (meth)acrylic acid 2-ethylhexyl ester, and (meth)acrylic acid hydroxyethyl ester. The (Ci) component may be used alone or in combination of two or more.

[0081] ((Cii) Bifunctional vinyl monomers) Examples of the bifunctional vinyl monomer having two polymerizable ethylenically unsaturated groups include polyethylene glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, polypropylene glycol di(meth)acrylate, 2,2-bis(4-(meth)acryloxypolyethoxypolypropoxyphenyl)propane, bisphenol A diglycidyl ether di(meth)acrylate, etc. The component (Cii) may be used alone or in combination of two or more.

[0082] ((Ciii) Multifunctional vinyl monomer) Examples of the polyfunctional vinyl monomer having at least three polymerizable ethylenically unsaturated groups include (meth)acrylate compounds having a skeleton derived from trimethylolpropane, such as trimethylolpropane tri(meth)acrylate; (meth)acrylate compounds having a skeleton derived from tetramethylolmethane, such as tetramethylolmethane tri(meth)acrylate and tetramethylolmethane tetra(meth)acrylate; (meth)acrylate compounds having a skeleton derived from pentaerythritol, such as pentaerythritol tri(meth)acrylate and pentaerythritol tetra(meth)acrylate; (meth)acrylate compounds having a skeleton derived from dipentaerythritol, such as dipentaerythritol penta(meth)acrylate and dipentaerythritol hexa(meth)acrylate; (meth)acrylate compounds having a skeleton derived from ditrimethylolpropane, such as ditrimethylolpropane tetra(meth)acrylate; and (meth)acrylate compounds having a skeleton derived from diglycerin. Among these, from the viewpoint of improving chemical resistance after curing (exposure) and increasing the difference in developer resistance between exposed and unexposed areas, (meth)acrylate compounds having a skeleton derived from dipentaerythritol are preferred, and dipentaerythritol hexa(meth)acrylate is more preferred. The component (Ciii) may be used alone or in combination of two or more.

[0083] The content of component (C) in the photosensitive resin composition is not particularly limited, but may be 0.2 to 15 mass%, 0.5 to 10 mass%, or 1 to 5 mass%, based on the total solid content of the photosensitive resin composition.

[0084] (Component (D): Photopolymerization initiator) The photopolymerization initiator as component (D) is not particularly limited as long as it can polymerize components (A) and (C). Component (D) may be used alone or in combination of two or more.

[0085] Examples of component (D) include acetophenone compounds such as acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1,2-methyl-[4-(methylthio)phenyl]-2-morpholino-1-propane, and N,N-dimethylaminoacetophenone; anthraquinone compounds such as 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, and 2-aminoanthraquinone; benzophenone, methylbenzophenone, 4,4'-dichlorobenzophenone, and the like. benzophenone compounds such as benzophenone, 4,4'-bis(diethylamino)benzophenone, Michler's ketone, and 4-benzoyl-4'-methyldiphenyl sulfide; acridine compounds such as 9-phenylacridine and 1,7-bis(9,9'-acridinyl)heptane; acylphosphine oxide compounds such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide; and oxime ester compounds such as 1,2-octanedione-1-[4-(phenylthio)phenyl]-2-(O-benzoyloxime), 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone-1-(O-acetyloxime), and 1-phenyl-1,2-propanedione-2-[O-(ethoxycarbonyl)oxime].

[0086] The content of the component (D) in the photosensitive resin composition is not particularly limited, but may be 0.2 to 15 mass%, 0.5 to 10 mass%, or 1 to 5 mass%, based on the total solid content of the photosensitive resin composition.

[0087] (Component (E): Secondary thiol compound) The photosensitive resin composition of this embodiment contains a secondary thiol compound as component (E). The secondary thiol compound is a compound having a secondary thiol group. When the photosensitive resin composition contains component (E), a permanent resist having good crack resistance and excellent insulation reliability can be formed. Furthermore, the photosensitive resin composition of this embodiment can form a permanent resist that is resistant to cracking even when subjected to a thermal cycle test, and further, can form a permanent resist that is resistant to cracking and peeling around the vias even when vias are formed in the permanent resist.

[0088] Component (E) may contain a polyfunctional secondary thiol compound having two or more secondary thiol groups. The use of a polyfunctional secondary thiol compound increases the crosslink density of the permanent resist, improving crack resistance and insulation reliability.

[0089] Component (E) may contain a secondary thiol compound having at least one skeleton selected from the group consisting of a pentaerythritol skeleton and an isocyanuric ring skeleton. Use of a secondary thiol compound having such a skeleton reduces odor, improves workability and handling, provides good storage stability, and improves the curability of the photosensitive resin composition.

[0090] Examples of the (E) component include secondary butanethiol, 2,3-butanedithiol, hex-5-ene-3-thiol, secondary dodecanethiol, secondary heptanethiol, secondary hexanethiol, secondary octadecanethiol, secondary octanethiol, and 2-methyl-2-propanethiol. Examples of the (E) component include compounds represented by the following formulas (1) to (6). The (E) component can be used alone or in combination of two or more.

[0091] [ka] [ka] [ka] [ka] [ka] [ka]

[0092] The molecular weight of component (E) is preferably 150 or more, more preferably 400 or more. The molecular weight of component (E) is also preferably 5000 or less, more preferably 2000 or less, and even more preferably 1000 or less. When the molecular weight is 150 or more, volatilization during coating tends to be less likely. On the other hand, when the molecular weight is 5000 or less, developability tends to be less likely to deteriorate.

[0093] Furthermore, from the viewpoint of workability during production and product handling, it is more preferable that the molecular weight of component (E) is 400 or greater. If the molecular weight is less than 400, the odor tends to be strong when blending the materials and when handling the product, and workability and handling tend to be reduced. On the other hand, if the molecular weight is 400 or greater, the odor is suppressed and workability and handling improve.

[0094] The number of functional groups (number of secondary thiol groups) of component (E) is preferably 2 to 6, and more preferably 4 to 6. When the number of functional groups is 2 or more, crack resistance and insulation reliability tend to be improved, and when the number is 6 or less, crack resistance and insulation reliability tend to be further improved while development residues are reduced.

[0095] The thiol equivalent of component (E) is preferably 50 g / eq or more and 500 g / eq or less, and more preferably 120 g / eq or more and 400 g / eq or less. When the thiol equivalent is 50 g / eq or more, pattern formability tends to be further improved. On the other hand, when the thiol equivalent is 500 g / eq or less, pattern formability tends to be further improved while reducing development residue.

[0096] The content of component (E) in the photosensitive resin composition is preferably 0.05% by mass or more, and may be 0.05 to 3.0% by mass, 0.05 to 2.5% by mass, or 0.05 to 2.0% by mass, based on the total solid content of the photosensitive resin composition. When the content of component (E) is 0.05% by mass or more, the crack resistance and insulation reliability of the permanent resist tend to be further improved, and when it is 3.0% by mass or less, the developability tends to be less likely to deteriorate.

[0097] (Component (F): inorganic filler) The photosensitive resin composition according to this embodiment may further contain an inorganic filler as component (F). By containing component (F), the adhesive strength and hardness of the permanent resist can be improved. The component (F) may be used alone or in combination of two or more.

[0098] Examples of materials for the inorganic filler 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.

[0099] Component (F) may contain a silica filler from the viewpoint of improving the heat resistance of the permanent resist, or may contain a barium sulfate filler or a combination of a silica filler and a barium sulfate filler from the viewpoint of improving the heat resistance and adhesive strength of the permanent resist. Furthermore, component (F) may contain an inorganic oxide filler or a silica filler from the viewpoint of further improving heat dissipation. To improve the dispersibility of the inorganic filler, an inorganic filler that has been surface-treated in advance with alumina or an organosilane compound may be used.

[0100] There are no particular restrictions on the shape of component (F), but from the perspective of further improving crack resistance, it may be spherical.

[0101] From the viewpoint of resolution, the average particle size of the component (F) 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.

[0102] The average particle size of component (F) is the average particle size of the inorganic filler dispersed in the photosensitive resin composition, and is a value obtained by measuring 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 (manufactured by Beckman Coulter, Inc., product name "N5") in accordance with the international standard ISO 13321 at a refractive index of 1.38, and the particle size at 50% cumulative value (volume basis) in the particle size distribution is taken as the average particle size.

[0103] The content of component (F) may be 5 to 80 mass%, 5 to 70 mass%, 6 to 60 mass%, or 10 to 50 mass%, based on the total solid content of the photosensitive resin composition. When the content of component (F) is within the above range, the low thermal expansion coefficient, heat resistance, and film strength can be further improved.

[0104] (Component (G): Photosensitizer) The photosensitive resin composition of the present embodiment may further contain a photosensitizer as component (G). When the photosensitive resin composition contains component (G), it is possible to effectively utilize the absorption wavelength of the actinic ray used for exposure.

[0105] Examples of the photosensitizer serving as component (G) include thioxanthone compounds such as 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, and 2,4-diisopropylthioxanthone; phosphine compounds such as triphenylphosphine; toluidine compounds such as N,N-dimethyltoluidine; anthracene compounds such as 9,10-dimethoxyanthracene, 2-ethyl-9,10-dimethoxyanthracene, and 2-ethyl-9,10-diethoxyanthracene; perylene compounds; coumarin compounds; pyrarizone compounds; oxazole compounds; thiazole compounds, benzoxazole compounds; thiazole compounds; triazole compounds; stilbene compounds; triazine compounds; thiophene compounds; naphthalimide compounds; and triarylamine compounds.

[0106] As the photosensitizer, from the viewpoint of maintaining a good via shape, 2,4-dimethylthioxanthone or 2,4-diethylthioxanthone is preferable, and 2,4-diethylthioxanthone is more preferable. Use of 2,4-diethylthioxanthone tends to reduce light scattering to unexposed areas, and as a result, the via shape can be maintained in a good state.

[0107] The content of component (G) is preferably 0.01 to 5 mass%, more preferably 0.05 to 3 mass%, even more preferably 0.1 to 2 mass%, and particularly preferably 0.3 to 1.5 mass%, based on the total solid content of the photosensitive resin composition.

[0108] (Component (H): Elastomer) The photosensitive resin composition of this embodiment may further contain an elastomer as component (H). By containing component (H), the photosensitive resin composition can suppress a decrease in flexibility and adhesive strength caused by strain (internal stress) inside the resin due to cure shrinkage of component (A).

[0109] Examples of component (H) include styrene-based elastomers, olefin-based elastomers, urethane-based elastomers, polyester-based elastomers, polyamide-based elastomers, acrylic elastomers, and silicone-based 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-based elastomers, polyester-based elastomers, and acrylic elastomers are preferred, and olefin-based elastomers are more preferred from the viewpoint of resolution. Component (G) can be used alone or in combination of two or more.

[0110] The content of component (H) may be 4 to 40 parts by mass, 4 to 30 parts by mass, 4 to 20 parts by mass, or 4 to 15 parts by mass per 100 parts by mass of component (A). When the content of component (H) is within the above range, the elastic modulus of the cured film in the high temperature range decreases, and the unexposed areas become more easily eluted in a developer.

[0111] (Component (I): Pigment) The photosensitive resin composition according to this embodiment may further contain a pigment as component (I) from the viewpoint of improving the distinguishability or appearance of the production equipment. As component (I), a colorant that develops a desired color when concealing wiring (conductor pattern) or the like can be used. One type of component (I) may be used alone, or two or more types may be used in combination.

[0112] Examples of the component (I) include phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, titanium oxide, carbon black, and naphthalene black.

[0113] The content of component (I) may be 0.01 to 5.0 mass%, 0.03 to 3.0 mass%, or 0.05 to 2.0 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 further concealing the wiring.

[0114] (Other ingredients) The photosensitive resin composition according to this embodiment may further contain various additives as needed, such as polymerization inhibitors such as hydroquinone, methylhydroquinone, hydroquinone monomethyl ether, catechol, and pyrogallol; silicone-based, fluorine-based, and vinyl resin-based antifoaming agents; silane coupling agents; and flame retardants such as phosphate compounds, aromatic condensed phosphate esters, and halogen-containing condensed phosphate esters.

[0115] The photosensitive resin composition according to this embodiment may contain an organic filler such as a resin filler, but from the viewpoint of resolution, it may not contain such an organic filler. The content of the organic filler in the photosensitive resin composition may be 1% by mass or less, or may be 0% by mass, based on the total solid content of the photosensitive resin composition.

[0116] (solvent) The photosensitive resin composition according to this embodiment contains a solvent for dissolving and dispersing each component, which makes it easy to apply onto a substrate and allows the formation of a coating film of uniform thickness.

[0117] 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 solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha. These solvents may be used alone or in combination of two or more.

[0118] The amount of the solvent to be added is not particularly limited, but the ratio of the solvent in the photosensitive resin composition may be 10 to 50 mass %, 20 to 40 mass %, or 25 to 35 mass %.

[0119] The photosensitive resin composition of this embodiment can be prepared by uniformly mixing the above-mentioned components using a roll mill, a bead mill, or the like.

[0120] [Photosensitive element] The photosensitive element according to this embodiment includes a support film and a photosensitive layer containing the above-described photosensitive resin composition. Fig. 1 is a cross-sectional view schematically showing the photosensitive element according to this embodiment. As shown in Fig. 1, the photosensitive element 1 includes a support film 10 and a photosensitive layer 20 formed on the support film 10.

[0121] The photosensitive element 1 can be produced by applying the photosensitive resin composition according to this embodiment onto a support film 10 by 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.

[0122] Examples of the support film 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 thickness of the photosensitive layer may be, for example, 5 to 50 μm, 5 to 40 μm, 10 to 30 μm, 15 to 30 μm, 20 to 30 μm, or 25 to 30 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.

[0123] The coating film can be dried by hot air drying, far infrared drying, or near infrared drying. The drying temperature may be 60 to 120° C., 70 to 110° C., or 80 to 100° C. The drying time may be 1 to 60 minutes, 2 to 30 minutes, or 5 to 20 minutes.

[0124] The photosensitive element 1 may further include a protective film 30 on the photosensitive layer 20 to cover the photosensitive layer 20. The photosensitive element 1 may also have the protective film 30 laminated on the surface of the photosensitive layer 20 opposite to the surface that contacts the support film 10. The protective film 30 may be, for example, a polymer film such as polyethylene or polypropylene.

[0125] The range of the solid content of each component (components (A) to (I) and other components) other than the volatile substance in the photosensitive layer 20 may be the same as the range of the solid content of each component in the photosensitive resin composition.

[0126] [Printed wiring board] The printed wiring board according to this embodiment includes a permanent resist containing a cured product of the photosensitive resin composition according to this embodiment.

[0127] The method for producing a printed wiring board according to this embodiment includes the steps of forming a photosensitive layer on a substrate using the above-described photosensitive resin composition or photosensitive element, exposing and developing the photosensitive layer to form a resist pattern, and curing the resist pattern to form a permanent resist. An example of each step will be described below.

[0128] First, a substrate such as a copper-clad laminate is prepared, and a photosensitive layer is formed on the substrate. The photosensitive layer may be formed by applying a photosensitive resin composition to the substrate and drying it. Examples of methods for applying 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 1 to 60 minutes, 2 to 30 minutes, or 3 to 20 minutes.

[0129] The photosensitive layer may be formed on the substrate by peeling off the protective film from the photosensitive element and laminating the photosensitive layer on the substrate. Examples of methods for laminating the photosensitive layer include thermal lamination using a laminator.

[0130] Next, a negative film is brought into contact with the photosensitive layer directly or via a support film, and exposed to actinic rays. Examples of actinic rays include electron beams, ultraviolet rays, and X-rays, with ultraviolet rays being preferred. Examples of light sources that can be used include low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, and halogen lamps. The exposure dose is 10 to 2000 mJ / cm. 2 , 100-1500mJ / cm 2 , or 300 to 1000 mJ / cm 2 may be.

[0131] After exposure, the unexposed areas are removed with a developer to form a resist pattern. Examples of the developing method include dipping and spraying. Examples of the developer that can be used include aqueous alkali solutions such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, and tetramethylammonium hydroxide.

[0132] A patterned cured film (permanent resist) can be formed by subjecting the resist pattern to at least one of post-exposure and post-heating. The exposure dose of the post-exposure is 100 to 5000 mJ / cm. 2 , 500~2000mJ / cm 2 , or 700 to 1500 mJ / cm 2 The heating temperature of the post-heating may be 100 to 200° C., 120 to 180° C., or 135 to 165° C. The heating time of the post-heating may be 5 minutes to 6 hours, 10 minutes to 3 hours, or 30 minutes to 2 hours.

[0133] The permanent resist may have vias with a diameter of 20 to 200 μm, or may have vias with a diameter of 40 to 150 μm. Even when such vias are formed in the permanent resist, the use of the photosensitive resin composition according to this embodiment can suppress the occurrence of cracks. Furthermore, the permanent resist may have both large vias with a diameter of 70 μm or more and small vias with a diameter of 35 μm or less. Even when such vias with different diameters are formed in the permanent resist, the use of the photosensitive resin composition according to this embodiment can suppress the occurrence of cracks for both diameters.

[0134] The permanent resist according to this embodiment can be used as an interlayer insulating layer or a surface protective layer of a semiconductor element. A semiconductor element having an interlayer insulating layer or a surface protective layer formed from a cured film of the above-described photosensitive resin composition, and an electronic device including the semiconductor element, can be produced. The semiconductor element may be, for example, a memory, a package, or the like having a multilayer wiring structure, a rewiring structure, or the like. 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, semiconductor elements and electronic devices with excellent reliability can be provided. [Example]

[0135] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to these examples.

[0136] (Synthesis Example 1) Bisphenol F novolac epoxy resin (manufactured by DIC Corporation, trade name "EXA-7376"; in formula (II), Y 3 and Y 4 is a glycidyl group, R 12 350 parts by weight of a bisphenol F novolac epoxy resin (epoxy equivalent: 186) having a structural unit in which ≡ is a hydrogen atom, 70 parts by weight of acrylic acid, 0.5 parts by weight of methylhydroquinone, and 120 parts by weight of carbitol acetate were mixed with stirring at 90°C. The mixture was cooled to 60°C, and 2 parts by weight of triphenylphosphine was added. The mixture was reacted at 100°C until the acid value of the solution reached 1 mgKOH / g or less. 98 parts by weight of tetrahydrophthalic anhydride (THPAC) and 85 parts by weight of carbitol acetate were added to the reaction mixture, and the mixture was reacted at 80°C for 6 hours. The reaction mixture was then cooled to room temperature to obtain a solution of acid-modified epoxy acrylate (A-1) (solids concentration: 73% by weight) as component (A).

[0137] The following materials were prepared as components (B) to (I). B-1: Tetramethylbisphenol F type epoxy resin (manufactured by Nippon Steel Chemical & Material Co., Ltd., product name "YSLV-80XY", first multifunctional epoxy resin, molecular weight 300 or more but less than 380) B-2: Novolac-type multifunctional epoxy resin (manufactured by Nippon Kayaku Co., Ltd., trade name "RE-306", second multifunctional epoxy resin, molecular weight 380 to 1200) C-1: Mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate (manufactured by Nippon Kayaku Co., Ltd., trade name "KAYARAD DPHA") D-1: 2-methyl-[4-(methylthio)phenyl]morpholino-1-propanone (manufactured by IGM Resins BV, trade name "Omnirad 907") D-2: 4,4'-bis(diethylamino)benzophenone (Tokyo Chemical Industry Co., Ltd.) E-1: Pentaerythritol tetrakis(3-mercaptobutyrate) (manufactured by Resonac Corporation, product name "Karenz MT PE1", number of functional groups: 4) E-2: 1,4-bis(3-mercaptobutyryloxy)butane (manufactured by Resonac Corporation, trade name "Karenz MT BD1", number of functional groups: 2) E-3: 1,3,5-tris(2-(3-sulfanylbutanoyloxy)ethyl)-1,3,5-triazinane-2,4,6-trione (manufactured by Resonac Corporation, trade name "KarenzMT NR1", number of functional groups: 3) E'-1: 2,2-bis[[(3-mercaptopropionyl)oxy]methyl]trimethylene bis[3-mercaptopropionate] (manufactured by Sakai Chemical Industry Co., Ltd., trade name "PEMP", primary thiol) F-1: Spherical silica filler (manufactured by Admatechs Co., Ltd., product name "SC2050", methacrylsilane surface treatment, average particle size: 0.5 μm) G-1: 2,4-diethylthioxanthone (manufactured by IGM Resins BV, trade name "Omnirad DETX") H-1: Epoxidized polybutadiene (manufactured by Daicel Corporation, product name "PB-3600") I-1: Phthalocyanine pigment (manufactured by Sanyo Pigment Co., Ltd.)

[0138] [Examples 1 to 8 and Comparative Examples 1 to 2] <Photosensitive resin composition> The components were blended in the amounts (parts by mass, solid content equivalent) shown in Table 1 and kneaded using a three-roll mill. Then, carbitol acetate was added so that the solid content concentration became 70% by mass, thereby preparing a photosensitive resin composition.

[0139] <Photosensitive element> A 25 μm-thick polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., product name "G2-25") was prepared as a support film. A solution prepared by diluting a photosensitive resin composition with methyl ethyl ketone was applied onto the support film so that the thickness after drying would be 18 μm, and the coating was dried at 75°C for 15 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 attached as a protective film to the surface of the photosensitive layer opposite the side in contact with the support film, thereby obtaining a photosensitive element.

[0140] [Crack resistance evaluation] The copper foil surface of a printed wiring board substrate (manufactured by Resonac Corporation, product name "MCL-E-679"), which had a 12 μm-thick copper foil laminated to a glass epoxy base, was treated with a roughening treatment solution (manufactured by MEC Co., Ltd., product name "CZ-8100"), rinsed with water, and then dried to obtain a roughened printed wiring board substrate. Next, the protective film was peeled off from the photosensitive element obtained in each example and comparative example, and the exposed photosensitive layer was placed in contact with the copper foil of the roughened printed wiring board substrate. The laminate was then laminated using a press-type vacuum laminator (manufactured by Meiki Seisakusho Co., Ltd., product name "MVLP-500"). The lamination conditions were a press hot plate temperature of 70°C, a vacuum time of 20 seconds, a lamination press time of 30 seconds, an atmospheric pressure of 4 kPa or less, and a pressure of 0.4 MPa. After lamination, the laminate was left standing at room temperature for at least 1 hour to obtain a laminate in which the photosensitive layer and the support film were laminated in this order on the copper foil surface of the substrate for printed wiring board.

[0141] A 41-step tablet was placed on the support film of the laminate, and exposure was performed using a direct imaging exposure device (manufactured by Oak Manufacturing Co., Ltd., product name "DXP-3512") using an ultra-high pressure mercury lamp as a light source. After exposure, the laminate was left at room temperature for 30 minutes, and then the support film was peeled off and removed. The unexposed areas of the photosensitive resin composition were spray-developed for 60 seconds using a 1% by weight aqueous solution of sodium carbonate at 30°C. After development, the amount of exposure energy required for the 41-step tablet to have a remaining gloss step number of 10.0 was determined.

[0142] The support film of the laminate was peeled off and removed, and an exposure mask for forming a square via pattern (opening size: 40-200 μm per side) was placed on the exposed photosensitive layer. Using a direct imaging exposure device (manufactured by Oak Manufacturing Co., Ltd., product name "DXP-3512") with an ultra-high pressure mercury lamp as the light source, exposure was carried out at an exposure energy amount that resulted in a gloss remaining step number of 10.0 for the 41-step tablet calculated above. After exposure, the sample was left at room temperature for 30 minutes, and then the unexposed areas of the photosensitive layer were spray-developed for 60 seconds using a 1% by mass aqueous solution of sodium carbonate at 30°C. After development, a total of 2000 mJ / cm was applied using an ultraviolet exposure device. 2 As a result, a laminate for evaluation was obtained in which a cured film (permanent resist) having square via openings was formed on the copper foil surface of the substrate for printed wiring board.

[0143] The resulting evaluation laminate was exposed to air at -65°C for 15 minutes, then heated to 150°C at a heating rate of 180°C / min, and then exposed to air at 150°C for 15 minutes, followed by cooling to -65°C at a heating rate of 180°C / min. This thermal cycle was repeated 1,000 times. After the thermal cycle test under these conditions, the permanent resist of the evaluation laminate was observed using a metallurgical microscope at 100x magnification at 20 locations on via openings with opening sizes of 60 μm on a side and 70 μm on a side. The presence or absence of cracks and peeling was observed, and the crack resistance was evaluated according to the following criteria. The results are shown in Table 1. A rating of A or B was considered to indicate good crack resistance. In Comparative Example 2, the curing reaction of the photosensitive layer proceeded at room temperature during the preparation of the evaluation laminate, resulting in development residue and making it unusable for evaluation. Since crack resistance could not be evaluated for Comparative Example 2, insulation reliability was also not evaluated. A: Neither cracking nor peeling was observed in the permanent resist at any of the 20 locations observed. B: Cracks and / or peeling were observed in the permanent resist at 1 to 4 of the 20 observed locations. C: Cracks and / or peeling were observed in the permanent resist at 5 or more of the 20 observed locations.

[0144] [Evaluation of insulation reliability] Test specimens were prepared in the same manner as in the above [Evaluation of crack resistance], except that an evaluation substrate with interdigital electrodes (line / space = 10 μm / 10 μm) was used instead of a copper-clad laminate substrate and that the entire surface was exposed to light. The test specimens were then exposed to conditions of 130°C, 85% RH, and 6 V for 250 hours. The resistance between the electrodes was measured, and the resistance was 10 -6 The time when the resistance dropped to Ω or less was taken as the time when copper migration occurred. The measurement results of the time when copper migration occurred are shown as HAST retention times in Table 1. If the HAST retention time was 200 hours or more, it was determined that the insulation reliability was excellent.

[0145] [Table 1] [Explanation of symbols]

[0146] 1...photosensitive element, 10...support film, 20...photosensitive layer, 30...protective film.

Claims

1. A photosensitive resin composition comprising (A) an acid-modified vinyl group-containing resin, (B) a thermosetting resin, (C) a photopolymerizable compound, (D) a photopolymerization initiator, and (E) a secondary thiol compound.

2. 2. The photosensitive resin composition according to claim 1, wherein the content of the component (E) is 0.05% by mass or more based on the total solid content of the photosensitive resin composition.

3. 2. The photosensitive resin composition according to claim 1, wherein the content of the component (E) is 0.05 to 3.0 mass% based on the total solid content of the photosensitive resin composition.

4. 2. The photosensitive resin composition according to claim 1, wherein the component (E) has 2 to 6 functional groups.

5. 2. The photosensitive resin composition according to claim 1, wherein the component (B) comprises a first multifunctional epoxy resin having a molecular weight of less than 380 and a second multifunctional epoxy resin having a molecular weight of 380 or more.

6. 6. The photosensitive resin composition according to claim 5, wherein the mass ratio of the content of the component (E) to the content of the second multifunctional epoxy resin is 0.005 to 0.

5.

7. The photosensitive resin composition according to claim 1 , further comprising (F) an inorganic filler.

8. The photosensitive resin composition according to claim 1 , further comprising (G) a photosensitizer.

9. The photosensitive resin composition according to claim 1 , further comprising (H) an elastomer.

10. A support film and a photosensitive layer formed on the support film, A photosensitive element, wherein the photosensitive layer comprises the photosensitive resin composition according to any one of claims 1 to 9.

11. A printed wiring board comprising a permanent resist comprising a cured product of the photosensitive resin composition according to any one of claims 1 to 9.

12. forming a photosensitive layer on a substrate using the photosensitive resin composition according to any one of claims 1 to 9; exposing and developing the photosensitive layer to form a resist pattern; hardening the resist pattern to form a permanent resist; A method for manufacturing a printed wiring board, comprising:

13. forming a photosensitive layer on a substrate using the photosensitive element of claim 10; exposing and developing the photosensitive layer to form a resist pattern; hardening the resist pattern to form a permanent resist; A method for manufacturing a printed wiring board, comprising:

Images