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

[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] Conventionally, permanent resists have been manufactured by screen printing using a thermosetting resin composition or by photographic methods 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 heat-cured to form a permanent resist, except for the wiring patterns that connect to IC chips, electronic components, or LCD (liquid crystal display) panels (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, in order to flip-chip mount semiconductor elements on the semiconductor package substrate via solder, (2) to wire-bond and join the semiconductor element and the semiconductor package substrate, and (3) to solder-join the semiconductor package substrate onto the motherboard substrate, it is necessary to remove the permanent resist of the joint portion. For image formation of the permanent resist, a photolithography method is used in which a photosensitive resin composition is applied and dried, and then selectively irradiated with actinic rays such as ultraviolet rays to be cured, and only the unirradiated portion is removed by development to form an image. Since the photolithography method is suitable for mass production due to its good workability, it is widely used in the electronic materials industry for image formation of photosensitive materials (see, for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] In response to the higher density of printed wiring boards, further high performance is required for the permanent resist (solder resist). In particular, the requirements regarding crack resistance and insulation reliability are increasing year by year, and it has become important to highly balance these characteristics. However, the permanent resist formed from the conventional photosensitive resin composition has a problem that cracks are likely to occur when a thermal cycle test is performed. In addition, the permanent resist formed from the conventional photosensitive resin composition may cause a short circuit due to migration within less than 200 hours of the test time in the HAST (Highly Accelerated Stress Test), which is 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 with good crack resistance and excellent insulation reliability, a photosensitive element using the photosensitive resin composition, a printed circuit board, and a method for manufacturing a printed circuit board. [Means for solving the problem]

[0008] To solve the above problems, this disclosure provides the following photosensitive resin composition, photosensitive element, printed circuit board, and method for manufacturing a printed circuit board.

[0009] [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] The photosensitive resin composition according to [1] above, wherein the content of component (E) is 0.05% by mass or more based on the total amount of solids in the photosensitive resin composition. [3] The photosensitive resin composition according to [1] or [2] above, wherein the content of component (E) is 0.05 to 3.0% by mass based on the total amount of solids in the photosensitive resin composition. [4] The photosensitive resin composition according to any one of [1] to [3] above, wherein the number of functional groups of component (E) is 2 to 6. [5] The photosensitive resin composition according to any one of [1] to [4] above, wherein component (B) comprises a first polyfunctional epoxy resin having a molecular weight of less than 380 and a second polyfunctional epoxy resin having a molecular weight of 380 or more. [6] The photosensitive resin composition according to [5], wherein the mass ratio of the content of component (E) to the content of the second polyfunctional epoxy resin is 0.005 to 0.5. [7](F) A photosensitive resin composition according to any one of [1] to [6] above, further containing an inorganic filler. [8](G) A photosensitive resin composition according to any one of [1] to [7] above, further comprising a photosensitizer. [9](H) A photosensitive resin composition according to any one of the above [1] to [8], further containing 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 described in any of [1] to [9] above.

[11] A printed circuit board comprising a permanent resist containing a cured product of any of the photosensitive resin compositions described in [1] to [9] above.

[12] A method for manufacturing a printed circuit board, comprising the steps of: forming a photosensitive layer on a substrate using a photosensitive resin composition described in any 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 circuit 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 this disclosure, it is possible to provide a photosensitive resin composition that can form a permanent resist with good crack resistance and excellent insulation reliability, a photosensitive element using the photosensitive resin composition, a printed circuit board, and a method for manufacturing a printed circuit board. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic cross-sectional view showing a photosensitive element according to this embodiment. [Modes for carrying out the invention]

[0012] 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.

[0013] 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.

[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, "solids" refers to the non-volatile components contained in the 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).

[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 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.

[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 groups having an ethylenically unsaturated bond 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.

[0018] 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 sometimes referred to as "component (a)") with (b) an ethylenically unsaturated group-containing organic acid (hereinafter sometimes referred to as "component (b)") with (c) a saturated or unsaturated group-containing polybasic acid anhydride (hereinafter sometimes referred to as "component (c)").

[0019] 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.

[0020] (A) components include, for example, an acid-modified vinyl group-containing resin (A1) (hereinafter sometimes referred to as "epoxy resin (a1)") formed using a bisphenol novolak type epoxy resin (a1) as the (a) component, and an acid-modified vinyl group-containing resin (A2) (hereinafter sometimes referred to as "(A2) component") formed using an epoxy resin (a2) other than epoxy resin (a1) as the (a) component.

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

[0022] [Chemical formula]

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

[0024] The number of structural units represented by formula (I) in 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 the copper substrate, heat resistance, and electrical insulation. Here, the number of structural units in a structural unit is an integer value for a single molecule, and a rational number which is the average value for an aggregate of multiple types of molecules. The same applies to the number of structural units in structural units hereafter.

[0025] [ka]

[0026] In formula (II), R 12 R represents a hydrogen atom or a methyl group, and there are multiple R 12 They may be the same or different. 3 and Y 4 Each of these independently represents a hydrogen atom or a glycidyl group, but Y 3 and Y 4 At least one of them is a glycidyl group. From the viewpoint of suppressing the occurrence of undercuts and improving the linearity and resolution of the resist pattern contour, R 12 It is preferably a hydrogen atom, and from the viewpoint of further improving thermal shock resistance, Y 3 and Y 4 It is preferable that it is 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 the copper substrate, and heat resistance.

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

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

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

[0031] As the epoxy resin (a2), a novolac-type epoxy resin having a structural unit represented by the following formula (III) is preferred. Examples of novolac-type epoxy resins having such a structural unit include a novolac-type epoxy resin represented by the following formula (III').

[0032] [ka]

[0033] In equations (III) and (III'), R 13 Y represents a hydrogen atom or a methyl group. 5 Y represents a hydrogen atom or a glycidyl group, 5At least one of them is a glycidyl group. In formula (III'), n1 is a number of 1 or more, and multiple R 13 and Y 5 These may be the same or different. From the viewpoint of suppressing the occurrence of undercuts and improving the linearity and resolution of the resist pattern contour, R 13 It is preferable that it be a hydrogen atom.

[0034] In equation (III'), Y is a hydrogen atom. 5 and the glycidyl group Y 5 The molar ratio may be 0 / 100 to 30 / 70 or 0 / 100 to 10 / 90, from the viewpoint of suppressing the occurrence of undercuts and improving the linearity and resolution of the resist pattern contour. n1 is 1 or greater, but may 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 the copper substrate, and heat resistance tend to improve.

[0035] Examples of novolac-type epoxy resins represented by formula (III') include phenol novolac-type epoxy resins and cresol novolac-type epoxy resins. These novolac-type 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] Examples of commercially available phenol novolac type epoxy resins or cresol novolac type epoxy resins represented by formula (III') include YDCN-700-7, YDCN-700-10, YDCN-704, YDCN-704A, YDPN-638 (all manufactured by Nippon Steel Chemical & Material Co., Ltd., trade names), EOCN-102S, EOCN-103S, EOCN-104S, EOCN-1012, EOCN-1027, BREN-S (all manufactured by Nippon Kayaku Co., Ltd., trade names), N-740, N-770, N-665, N-673 (all manufactured by DIC Corporation, trade names).

[0037] As the epoxy resin (a2), a bisphenol A type epoxy resin or a bisphenol F type epoxy resin having a structural unit represented by the following formula (IV) is preferred. Examples of epoxy resins having such a structural unit include a bisphenol A type epoxy resin or a bisphenol F type epoxy resin represented by the following formula (IV').

[0038] [ka]

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

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

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

[0042] Examples of commercially available bisphenol A-type epoxy resins or bisphenol F-type epoxy resins represented by formula (IV') include jER807, jER825, jER827, jER828, jER834, jER1004F, jER1007FS, and jER1009F (all manufactured by Mitsubishi Chemical Corporation, trade names), YD-8125, YDF-170, YDF-2001, YDF-2004, and YDF-8170C (all manufactured by Nippon Steel Chemical & Material Co., Ltd., trade names).

[0043] As the epoxy resin (a2), a triphenolmethane type epoxy resin having a structural unit represented by the following formula (V) is preferred. Examples of such triphenolmethane type epoxy resins having a structural unit include a triphenolmethane type epoxy resin represented by the following formula (V').

[0044] [ka]

[0045] In equations (V) and (V'), Y 7 Y represents a hydrogen atom or a glycidyl group, and there are multiple Y 7 They may be the same or different, and there is at least one Y 7 is a glycidyl group. In formula (V'), n3 represents a number greater than or equal to 1.

[0046] From the viewpoint of suppressing the occurrence of undercuts and upper defects and improving the linearity and resolution of the resist pattern contour, Y 7 Y is a hydrogen atom in 7 and the glycidyl group Y 7 The molar ratio of Y can be 0 / 100 to 30 / 70. As can be seen from this molar ratio, 7 At least one of the groups is a glycidyl group. n3 is 1 or greater, but may be 10-100, 15-80, or 15-70. When n3 is within the above range, the linearity of the resist pattern contour, adhesion to the copper substrate, and heat resistance tend to improve.

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

[0048] As the epoxy resin (a2), a biphenyl-type epoxy resin having a structural unit represented by the following formula (VI) is preferred. Examples of such biphenyl-type epoxy resins having a structural unit include a biphenyl-type epoxy resin represented by the following formula (VI').

[0049] [ka]

[0050] In equations (VI) and (VI'), Y 8 Y represents a hydrogen atom or a glycidyl group, and there are multiple Y 8 They may be the same or different, and there is at least one Y 8 is a glycidyl group. In formula (V'), n4 represents a number greater than or equal to 1.

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

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

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

[0054] (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.

[0055] 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.

[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, trimethylolpropanedi(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), it is preferable to react them in a ratio of 0.6 to 1.05 equivalents of component (b) per 1 equivalent of epoxy group of component (a), and more preferably in a ratio of 0.8 to 1.0 equivalents. Reacting in such a ratio tends to increase photosensitivity and improve the 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. A single polymerization inhibitor or a combination of two or more may be used.

[0060] From the viewpoint of improving stability, the amount of 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 components (a) and (b).

[0061] 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.

[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 group in component (A').

[0064] 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.

[0065] Component (A) preferably contains component (A1) from the viewpoint of suppressing the occurrence of undercuts and further improving adhesion to the copper substrate, thermal shock resistance, and resolution, and more preferably contains both component (A1) and component (A2) from the viewpoint of improving adhesion strength.

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

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

[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, the Mw of component (A) may be 3000 or more, 4000 or more, or 5000 or more. From the viewpoint of improving the resolution of the photosensitive layer, the Mw of component (A) may be 30000 or less, 25000 or less, or 18000 or less.

[0069] 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 5 samples ("PStQuick MP-H" and "PStQuick B," manufactured by Tosoh Corporation) can be used as the standard polystyrene to create the calibration curve. GPC equipment: High-speed GPC system "HCL-8320GPC" (manufactured by Tosoh Corporation) Detector: Differential refractometer or UV detector (manufactured by Tosoh Corporation) Column: TSKgel SuperMultipore HZ-H column (Column length: 15cm, Column inner diameter: 4.6mm) (Manufactured by Tosoh Corporation) Eluent: Tetrahydrofuran (THF) Measurement temperature: 40℃ Flow rate: 0.35mL / min Sample concentration: 10 mg / THF 5 mL Injection volume: 20μL

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

[0071] ((B) component: 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.

[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 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.

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

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

[0076] The content of components (B1) and (B2) in component (B) is not particularly limited, but from the viewpoint of improving developability, the mass ratio of the content of component (B1) to the content of component (B2) (content of component (B1) / content of 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 setting the mass ratio of component (B2) to component (E) within the above range, component (B2) and component (E) are more likely to react to form a cross-linked structure, thereby tending to improve crack resistance and insulation reliability.

[0078] 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.

[0079] ((C) component: photopolymerizable compound) Component (C) is not particularly limited as long as it is a compound having a functional group that exhibits photopolymerizability. Component (C) may be a photopolymerizable compound having an ethylenically unsaturated group that does not have an acidic group. Component (C) preferably comprises at least one selected from the group consisting of (Ci) a monofunctional vinyl monomer having one polymerizable ethylenically unsaturated group, (Cii) a difunctional vinyl monomer having two polymerizable ethylenically unsaturated groups, and (Ciii) a polyfunctional vinyl monomer having at least three polymerizable ethylenically unsaturated groups, and more preferably a component comprising at least the above-mentioned (Ciii) component. Components (Ci) to (Ciii) are preferably those with a molecular weight of 1000 or less.

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

[0081] ((Cii) Difunctional vinyl monomer) Examples of the two polymerizable ethylenically unsaturated difunctional vinyl monomers mentioned above include polyethylene glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, polypropylene glycol di(meth)acrylate, 2,2-bis(4-(meth)acryloxypolyethoxypolypropoxyphenyl)propane, and bisphenol A diglycidyl ether di(meth)acrylate. Component (Cii) may be used alone or in combination of two or more.

[0082] ((Ciii) Polyfunctional vinyl monomer) Examples of polyfunctional vinyl monomers having at least three polymerizable ethylenically unsaturated groups include (meth)acrylate compounds having a trimethylolpropane-derived skeleton such as trimethylolpropane tri(meth)acrylate; (meth)acrylate compounds having a tetramethylolmethane-derived skeleton such as tetramethylolmethane tri(meth)acrylate and tetramethylolmethane tetra(meth)acrylate; (meth)acrylate compounds having a pentaerythritol-derived skeleton such as pentaerythritol tri(meth)acrylate and pentaerythritol tetra(meth)acrylate; (meth)acrylate compounds having a dipentaerythritol-derived skeleton such as dipentaerythritol penta(meth)acrylate and dipentaerythritol hexa(meth)acrylate; (meth)acrylate compounds having a ditrimethylolpropane-derived skeleton such as ditrimethylolpropane tetra(meth)acrylate; and (meth)acrylate compounds having a diglycerin-derived skeleton. Among these, (meth)acrylate compounds having a dipentaerythritol-derived skeleton are preferred, and dipentaerythritol hexa(meth)acrylate is more preferred, from the viewpoint of improving chemical resistance after curing (exposure) and increasing the difference in developer resistance between the exposed and unexposed areas. 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% by mass, 0.5 to 10% by mass, or 1 to 5% by mass, based on the total solid content of the photosensitive resin composition.

[0084] (Component D: Photopolymerization initiator) The photopolymerization initiator, which is 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] (D) Component includes, for example, acetophenone compounds such as 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-dimethylaminoacetophenone; anthraquinone compounds such as 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, 2-aminoanthraquinone; benzophenone, methylbenzophenone, 4,4'-dichloroben Examples include benzophenone compounds such as zophenone, 4,4'-bis(diethylamino)benzophenone, Michlaz 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-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].

[0086] The content of component (D) in the photosensitive resin composition is not particularly limited, but may be 0.2 to 15% by mass, 0.5 to 10% by mass, or 1 to 5% by 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. By containing component (E) in the photosensitive resin composition, it is possible to form a permanent resist that has good crack resistance and excellent insulation reliability. Furthermore, according to the photosensitive resin composition of this embodiment, it is possible to form a permanent resist that is less prone to cracking even when thermal cycling tests are performed, and even when vias are formed in the permanent resist, it is possible to form a permanent resist that is less prone to cracking and delamination around the vias.

[0088] Component (E) may contain a polyfunctional secondary thiol compound having two or more secondary thiol groups. Using a polyfunctional secondary thiol compound can increase the crosslinking density of the permanent resist, thereby 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. By using secondary thiol compounds having these skeletons, odor can be suppressed, workability and handling can be improved, storage stability can be enhanced, and the curability of the photosensitive resin composition can be improved.

[0090] Examples of component (E) include secondary butanethiol, 2,3-butanedithiol, hexa-5-ene-3-thiol, secondary dodecanethiol, secondary heptanethiol, secondary hexanethiol, secondary octadecanethiol, secondary octanthiol, and 2-methyl-2-propanethiol. Furthermore, compounds represented by the following formulas (1) to (6) can also be considered as component (E). Component (E) can be used individually 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, and more preferably 400 or more. Furthermore, the molecular weight of component (E) is preferably 5000 or less, more preferably 2000 or less, and even more preferably 1000 or less. When the molecular weight is 150 or more, it tends to volatilize less during coating. On the other hand, when the molecular weight is 5000 or less, it tends to not deteriorate easily.

[0093] Furthermore, from the perspective of workability during manufacturing and product handling, it is more preferable that the molecular weight of component (E) be 400 or higher. When the molecular weight is less than 400, the odor tends to be strong when compounding the materials and when handling the product, resulting in reduced workability and handling. On the other hand, when the molecular weight is 400 or higher, the odor is suppressed and workability and handling are improved.

[0094] The number of functional groups (number of secondary thiol groups) in 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 improve, and when it is 6 or less, crack resistance and insulation reliability tend to improve further while reducing developing residue.

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

[0096] The content of component (E) in the photosensitive resin composition is preferably 0.05% by mass or more, based on the total solid content of the photosensitive resin composition, 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. 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 not to deteriorate.

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

[0098] Examples of inorganic filler materials 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 silica filler from the viewpoint of improving the heat resistance of the permanent resist, and may contain barium sulfate filler from the viewpoint of improving the heat resistance and adhesive strength of the permanent resist, or may contain both silica filler and barium sulfate filler. Furthermore, component (F) may contain inorganic oxide filler or silica filler from the viewpoint of further improving heat dissipation. From the viewpoint of improving the dispersibility of the inorganic filler, inorganic filler that has been pre-surface-treated with alumina or an organosilane compound may be used.

[0100] The shape of component (F) is not particularly limited, but it may be spherical from the viewpoint of further improving crack resistance.

[0101] The average particle size of 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, from the viewpoint of resolution.

[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 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 (manufactured by 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.

[0103] The content of component (F) may be 5 to 80% by mass, 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 (F) is within the above range, the low coefficient of thermal expansion, heat resistance, and film strength can be further improved.

[0104] ((G) component: photosensitizer) The photosensitive resin composition of this embodiment may further contain a photosensitizer as component (G). By including component (G) in the photosensitive resin composition, the absorption wavelength of the active light used for exposure can be effectively utilized.

[0105] Examples of photosensitizers, which are 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; pyrarisone compounds; oxazole compounds; thiazole compounds, benzoxazole compounds; thiazole compounds; triazole compounds; stilbene compounds; triazine compounds; thiophene compounds; naphthalimide compounds; and triarylamine compounds.

[0106] From the viewpoint of maintaining good via shape, the photosensitizer is preferably 2,4-dimethylthioxanthone or 2,4-diethylthioxanthone, and more preferably 2,4-diethylthioxanthone. Using 2,4-diethylthioxanthone tends to reduce scattered light to unexposed areas, and as a result, good via shape can be maintained.

[0107] The content of component (G) is preferably 0.01 to 5% by mass, more preferably 0.05 to 3% by mass, even more preferably 0.1 to 2% by mass, and particularly preferably 0.3 to 1.5% by 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 including component (H) in the photosensitive resin composition, it is possible to suppress the decrease in flexibility and adhesive strength caused by internal stress (strain) within the resin due to curing shrinkage of component (A).

[0109] Examples of component (H) 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, polyester elastomers, and acrylic elastomers are preferred, and olefin 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 region becomes lower, and the unexposed areas become more easily eluted by the developer.

[0111] ((I) Component: Pigment) The photosensitive resin composition according to this embodiment may further contain a pigment as component (I) from the viewpoint of improving the identifiability or appearance of the manufacturing apparatus. As component (I), a coloring agent that produces a desired color when concealing wiring (conductor patterns) can be used. Component (I) may be used alone or in combination of two or more types.

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

[0113] (I) The content of component (I) 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.

[0114] (Other ingredients) 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; silicone-based, fluorine-based, and vinyl resin-based defoaming 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 organic fillers such as resin fillers, but may not contain them from the viewpoint of resolution. The amount of organic fillers in the photosensitive resin composition may be 1% by mass or less, or 0% by mass, based on the total amount of solids in the photosensitive resin composition.

[0116] (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.

[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-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.

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

[0119] 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.

[0120] [Photosensitive element] The photosensitive element according to this embodiment comprises a support film and a photosensitive layer containing 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.

[0121] 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.

[0122] 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 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 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.

[0124] 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. As the protective film 30, for example, a polymer film such as polyethylene or polypropylene may be used.

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

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

[0127] The method for manufacturing a printed circuit board according to this embodiment comprises the steps of: forming a photosensitive layer on a substrate using the above-mentioned photosensitive resin composition or photosensitive element; forming a resist pattern by exposing and developing the photosensitive layer; and forming a permanent resist by curing the resist pattern. 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 coating a photosensitive resin composition onto the 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 60-120°C, 70-110°C, or 80-100°C. The drying time may be 1-60 minutes, 2-30 minutes, or 3-20 minutes.

[0129] 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.

[0130] 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 , 100~1500 mJ / cm 2 , or 300-1000 mJ / cm² 2 That's fine.

[0131] 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.

[0132] 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. 2 500-2000 mJ / cm² 2 , or 700-1500 mJ / cm² 2 The heating temperature for the post-heating may be 100-200°C, 120-180°C, or 135-165°C. The heating time for 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 vias with a diameter of 40 to 150 μm. Even when such vias are formed in the permanent resist, the occurrence of cracks can be suppressed by using the photosensitive resin composition according to this embodiment. Furthermore, the permanent resist may have both large-diameter vias with a diameter of 70 μm or more and small-diameter vias with a diameter of 35 μm or less. Even when such vias of different diameters are formed in the permanent resist, the occurrence of cracks can be suppressed at any diameter by using the photosensitive resin composition according to this embodiment.

[0134] The permanent resist according to this embodiment can be used as an interlayer insulating layer or surface protective layer of a semiconductor element. 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, package, etc., 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. [Examples]

[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 type 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 mass of bisphenol F novolac-type epoxy resin having a structural unit of a hydrogen atom (epoxy equivalent: 186), 70 parts by mass of acrylic acid, 0.5 parts by mass of methyl hydroquinone, and 120 parts by mass of carbitol acetate were mixed with stirring at 90°C. The mixture was cooled to 60°C, 2 parts by mass of triphenylphosphine were added, and the mixture was reacted at 100°C until the acid value of the solution was 1 mg KOH / g or less. 98 parts by mass of tetrahydrophthalic anhydride (THPAC) and 85 parts by mass of carbitol acetate were added to the reaction solution and the mixture was reacted at 80°C for 6 hours. The reaction solution was then cooled to room temperature to obtain a solution of acid-modified epoxy acrylate (A-1) as component (A) (solid content concentration: 73% by mass).

[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 type of polyfunctional epoxy resin, molecular weight 300 or more and less than 380) B-2: Novolac-type polyfunctional epoxy resin (manufactured by Nippon Kayaku Co., Ltd., product name "RE-306", second type of polyfunctional epoxy resin, molecular weight 380-1200) C-1: A 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 (manufactured by Tokyo Chemical Industry Co., Ltd.) E-1: Pentaerythritol tetrakis(3-mercaptobutyrate) (manufactured by Resonaq Corporation, product name "Kalenz MT PE1", number of functional groups: 4) E-2: 1,4-Bis(3-mercaptobutyryloxy)butane (manufactured by Resonaq Corporation, product name "Kalenz MT BD1", number of functional groups: 2) E-3: 1,3,5-Tris(2-(3-sulfanylbutanoyloxy)ethyl)-1,3,5-triazinan-2,4,6-trione (manufactured by Resonaq Corporation, product name "Kalenz MT 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 Admatex Co., Ltd., product name "SC2050", methacrylate silane surface treated product, average particle size: 0.5 μm) G-1: 2,4-Diethylthioxanthone (manufactured by IGM Resins BV, trade name "Omnirad DETX") H-1: Epoxy-modified polybutadiene (manufactured by Daicel Corporation, product name "PB-3600") I-1: Phthalocyanine-based pigment (manufactured by Sanyo Pigment Co., Ltd.)

[0138] [Examples 1-8 and Comparative Examples 1-2] <Photosensitive resin composition> Each component was blended in the amounts (parts by mass, equivalent to solid content) shown in Table 1 and kneaded in a three-roll mill. Then, carbitol acetate was added to achieve a solid content concentration of 70% by mass to prepare a photosensitive resin composition.

[0139] <Photosensitive element> A polyethylene terephthalate film with a thickness of 25 μm (manufactured by Toyobo Co., Ltd., product name "G2-25") 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 was 18 μm, and the film 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 laminated as a protective film onto the surface of the photosensitive layer opposite to the side in contact with the support film to obtain a photosensitive element.

[0140] [Evaluation of crack resistance] A roughened printed circuit board substrate (manufactured by Resonac Co., Ltd., product name "MCL-E-679"), in which 12 μm thick copper foil was laminated on a glass epoxy substrate, was treated with a roughening solution (manufactured by MEC Co., Ltd., product name "CZ-8100") on the copper foil surface, then washed with water and dried to obtain a roughened printed circuit board substrate. Next, the protective film was peeled off from the photosensitive elements obtained in each example and comparative example, and the exposed photosensitive layer was placed in contact with the copper foil of the roughened printed circuit board substrate. Then, lamination was performed using a press-type vacuum laminator (manufactured by Meiki Seisakusho Co., Ltd., product name "MVLP-500"). The lamination conditions were: press hot plate temperature 70°C, vacuuming time 20 seconds, lamination press time 30 seconds, atmospheric pressure 4 kPa or less, and compression pressure 0.4 MPa. After lamination, the substrate was left at room temperature for more than one hour to obtain a laminate in which a photosensitive layer and a support film were laminated in that order on the copper foil surface of the printed circuit board substrate.

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

[0142] The support film of the laminate was peeled off, and an exposure mask (aperture size: 40-200 μm per side) for forming a square via pattern was placed on the exposed photosensitive layer. Exposure was performed using a direct imaging exposure apparatus (manufactured by Oak Manufacturing Co., Ltd., product name "DXP-3512") with an ultra-high pressure mercury lamp as the light source, at an exposure energy amount that resulted in 10.0 remaining glossy step steps for the 41-step step tablet determined above. After exposure, the material was left at room temperature for 30 minutes, and then the unexposed photosensitive layer was spray-developed for 60 seconds using a 1% by mass sodium carbonate aqueous solution at 30°C. After development, a total of 2000 mJ / cm² was applied using an ultraviolet exposure apparatus. 2 Exposure was performed. As a result, an evaluation laminate was obtained in which a cured film (permanent resist) with square via openings was formed on the copper foil surface of a printed circuit board substrate.

[0143] The obtained 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 subsequently exposed to air at 150°C for 15 minutes, followed by a thermal cycle of cooling down to -65°C at a cooling rate of 180°C / min, repeated 1000 times. After the thermal cycling test under these conditions, the permanent resist of the evaluation laminate was observed at 20 via openings with aperture sizes of 60 μm and 70 μm on each side using a metallurgical microscope at 100x magnification. The presence or absence of cracks and delamination was observed, and crack resistance was evaluated according to the following criteria. The results are shown in Table 1. If the evaluation result was A or B, it was judged that the crack resistance was good. In Comparative Example 2, the photosensitive layer curing reaction proceeded at room temperature during the preparation of the evaluation laminate, resulting in the generation of development residue, so evaluation was not possible. For Comparative Example 2, since crack resistance could not be evaluated, insulation reliability was also not evaluated. A: No cracks or delaminations were observed in the permanent resist at any of the 20 locations examined. B: Of the 20 locations observed, cracks and / or delamination of the permanent resist were observed in 1 to 4 locations. C: Cracks and / or delamination of the permanent resist were observed in 5 or more of the 20 locations observed.

[0144] [Evaluation of insulation reliability] The test specimens were prepared in the same manner as in the [Evaluation of Crack Resistance] described above, except that an evaluation substrate with comb-shaped electrodes (line / space = 10 μm / 10 μm) was used instead of a copper-clad laminated substrate, and the entire surface was exposed to light. The test specimens were then exposed to 130°C, 85% RH, and 6 V for 250 hours. The resistance between the electrodes was measured, and if the resistance value was 10 -6 The time at which the resistance fell below Ω was defined as the copper migration occurrence time. The measured copper migration occurrence time is shown in Table 1 as the HAST retention time. If the HAST retention time was 200 hours or more, it was judged to have excellent insulation reliability.

[0145] [Table 1] [Explanation of Symbols]

[0146] 1...Photosensitive element, 10...Support film, 20...Photosensitive layer, 30...Protective film.

Claims

1. (A) Acid-modified vinyl group-containing resin, (B) Thermosetting resin, (C) Photopolymerizable compound, (D) Photopolymerization initiator, (E) Secondary thiol compound, (F) Inorganic filler, and (H) Elastomer are included. The aforementioned component (B) comprises a first polyfunctional epoxy resin having a molecular weight of less than 380 and a second polyfunctional epoxy resin having a molecular weight of 380 or more. A photosensitive resin composition in which the mass ratio of the content of the first polyfunctional epoxy resin to the content of the second polyfunctional epoxy resin is 1.0 to 5.

0.

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

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

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

5. The photosensitive resin composition according to claim 1, wherein the mass ratio of the content of component (E) to the content of the second polyfunctional epoxy resin is 0.005 to 0.

5.

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

7. The device comprises a support film and a photosensitive layer formed on the support film, A photosensitive element wherein the photosensitive layer comprises the photosensitive resin composition described in any one of claims 1 to 6.

8. A printed circuit board comprising a permanent resist containing a cured product of a photosensitive resin composition according to any one of claims 1 to 6.

9. A step of forming a photosensitive layer on a substrate using the photosensitive resin composition described in any one of claims 1 to 6, The process of exposing and developing the photosensitive layer to form a resist pattern, A step of curing the aforementioned resist pattern to form a permanent resist, A method for manufacturing printed circuit boards, comprising:

10. A step of forming a photosensitive layer on a substrate using the photosensitive element described in claim 7, The process of exposing and developing the photosensitive layer to form a resist pattern, A step of curing the aforementioned resist pattern to form a permanent resist, A method for manufacturing printed circuit boards, comprising:

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