Photosensitive resin laminate

Abstract

The present invention provides a photosensitive resin laminate for forming a resist pattern for forming a metal pillar and a semiconductor bump, the photosensitive resin laminate comprising a support film and a photosensitive resin layer that contains a photosensitive resin composition. The photosensitive resin composition contains, relative to the total solid content of the photosensitive resin composition, (A) 30 mass% to 70 mass% of an alkali-soluble polymer, (B) 20 mass% to 50 mass% of a compound that has an ethylenically unsaturated bond, and (C) 0.01 mass% to 20 mass% of a photopolymerization initiator. The component (B) includes (B-1) a compound that has a cyclic group, an ethylene oxide chain, and two acryloyl groups in each molecule, and (B-2) a compound that has three or more acryloyl groups. The photosensitive resin layer has a thickness of 80 µm or more.

Description

Photosensitive resin laminate

[0001] The present disclosure relates to a photosensitive resin laminate.

[0002] Conventionally, photolithography has been used for the manufacture of printed wiring boards and precision processing of metals. Photosensitive resin laminates used in photolithography are classified into negative-type, in which unexposed areas are dissolved and removed, and positive-type, in which exposed areas are dissolved and removed.

[0003] A general method for forming a pattern using a photosensitive resin laminate will be briefly described. First, the protective layer is peeled off from the photosensitive resin laminate. Using a laminator, a photosensitive resin layer and a support are laminated on a substrate such as a copper-clad laminate or a copper-sputtered thin film in the order of substrate, photosensitive resin layer, and support. The photosensitive resin layer is exposed to light through a photomask bearing a desired wiring pattern. After exposure, the support is peeled off from the laminate, and the unexposed or exposed areas are dissolved or dispersed and removed using a developer, forming a resist pattern on the substrate. The substrate bearing the resist pattern is then subjected to plating processes such as copper plating or solder plating, and the resist pattern is then peeled off, allowing for metal pattern formation, wiring, metal pillar or semiconductor bump formation, semiconductor packaging, and the like.

[0004] Various photosensitive resin laminates have been studied for forming resist patterns or metal patterns using the same. For example, Patent Documents 1 to 3 describe photosensitive resin laminates having a photosensitive resin layer containing a specific alkali-soluble polymer, a photopolymerizable monomer, and a photopolymerization initiator. Patent Document 2 also studies the relationship between the film thickness and absorbance of the photosensitive resin layer.

[0005] International Publication No. 2011 / 037182 International Publication No. 2021 / 095784 International Publication No. 2022 / 085366

[0006] In recent years, there has been a demand for finer and denser wiring, and accordingly, plating methods have become more widely used as a method for forming metal wiring. The shape of wiring formed by plating methods depends on the shape and thickness of the resist pattern. In plating methods, a photosensitive resin laminate having a thick photosensitive resin layer is generally used, and a resist pattern formed by exposing and developing the photosensitive resin laminate is subjected to metal plating and then treated with a stripping solution.

[0007] If the strippability of the cured resist pattern is poor, the solubility of the peeled pieces will also be poor, the stripping process including immersion of the resist pattern in the stripping solution, stripping and dissolution will take a long time, and the stripped cured resist may not be completely dissolved and may remain as residue in the stripping solution.

[0008] For example, if a photosensitive resin with poor processability in a stripper solution is used, the stripped cured resist does not dissolve and remains as a residue in the stripper solution. The retained stripping residue remains on the plating pattern, causing defects. Therefore, the processability of the photosensitive resin in a stripper solution (hereinafter also referred to as "stripping processability") is required. Furthermore, the stripper solution used to remove the cured resist pattern consumes its components as it is removed. If a photosensitive resin with significant component consumption is used, problems such as stripping residue are likely to occur and productivity will decrease unless the stripper solution is made up more frequently. Therefore, it is required to reduce the frequency of stripper solution preparation (hereinafter also referred to as "stripper solution fatigue").

[0009] Furthermore, photosensitive resins used in plating processes are also required to reduce the phenomenon in which plating penetrates into the bottom of a cured resist pattern during plating processing (hereinafter also referred to as "plating penetration") and the resulting footing of the metal pattern.

[0010] The problem of strippability or plating penetration of a cured resist pattern is particularly pronounced in thick-film photosensitive resin layers or circular hole-shaped resist patterns, such as resist patterns for forming metal pillars and semiconductor bumps, formation of metal cylinder or polygonal column patterns using resist patterns with a specific ratio of circular hole diameter to film thickness, stripping using a stripping solution that does not contain dimethyl sulfoxide (DMSO) to reduce the environmental load, wafer level packaging (WLP), etc.

[0011] Therefore, an object of the present disclosure is to provide a photosensitive resin laminate that can improve the removability of a resist pattern.

[0012] The present inventors have discovered that the above-mentioned problems can be solved by specifying the structure and content of each component of a photosensitive resin composition in a photosensitive resin laminate including a support film and a photosensitive resin layer containing a photosensitive resin composition, and have completed the present invention. Examples of embodiments of the present disclosure are listed in the following items. (1) A photosensitive resin laminate for forming a resist pattern to form metal pillars and semiconductor bumps, comprising a support film and a photosensitive resin layer containing a photosensitive resin composition, wherein the photosensitive resin composition contains, relative to the total solid content of the photosensitive resin composition: (A) 30% by mass to 70% by mass of an alkali-soluble polymer; (B) 20% by mass to 50% by mass of a compound having an ethylenically unsaturated bond; and (C) 0.01% by mass to 20% by mass of a photopolymerization initiator; and the component (B) contains at least: (B-1) a compound having a cyclic group, an ethylene oxide chain, and two acryloyl groups in one molecule; and (B-2) a compound having three or more acryloyl groups; and the photosensitive resin layer has a thickness of 80 μm or more. (2) The compound (B-1) is represented by the following general formula (II): {wherein each EO independently represents ethylene oxide, each A independently represents an acryloyl group, and m and n independently represent an integer of 1 to 100.} (3) The photosensitive resin laminate for forming a resist pattern for forming a metal pillar and a semiconductor bump according to item 1 or 2, wherein the mass ratio (methacrylate monomer / acrylate monomer) of the compound having a methacryloyl group to the compound having an acryloyl group in component (B) is 0 or more and less than 0.5. (4) The photosensitive resin laminate for forming a resist pattern for forming a metal pillar and a semiconductor bump according to any one of items 1 to 3, wherein the mass ratio (methacrylate monomer / acrylate monomer) of the compound having a methacryloyl group to the compound having an acryloyl group in component (B) is less than 0.1. (5) The photosensitive resin laminate for forming a resist pattern for forming metal pillars and semiconductor bumps according to any one of items 1 to 4, wherein the concentration of ethylenically unsaturated bonds in the photosensitive resin layer is 1.0 mmol / g or more. (6) The photosensitive resin laminate for forming a resist pattern for forming metal pillars and semiconductor bumps according to any one of items 1 to 5, wherein the mass ratio of the monomer modified with an alkylene oxide having 3 or more carbon atoms to the EO-modified monomer in component (B) ((monomer modified with an alkylene oxide having 3 or more carbon atoms) / EO-modified monomer) is 0 or more and less than 0.1. (7) The photosensitive resin laminate for forming a resist pattern for forming metal pillars and semiconductor bumps according to any one of items 1 to 6, wherein the mass ratio of the propylene oxide or butylene oxide-modified monomer to the ethylene oxide-modified monomer in component (B) ((propylene oxide-modified monomer+butylene oxide-modified monomer) / ethylene oxide-modified monomer) is 0 or more and less than 0.1. (8) The photosensitive resin laminate for forming a resist pattern for forming a metal pillar and a semiconductor bump according to any one of items 1 to 7, wherein the component (B) further contains a compound having a monofunctional ethylenic double bond.(9) The photosensitive resin laminate for forming a resist pattern for forming a metal pillar and a semiconductor bump according to any one of items 1 to 8, wherein the component (A) comprises a copolymer having a monomer having an aromatic ring as a copolymerization component. (10) The photosensitive resin laminate for forming a resist pattern for forming a metal pillar and a semiconductor bump according to any one of items 1 to 9, wherein the component (A) comprises a copolymer having benzyl (meth)acrylate as a copolymerization component. (11) A photosensitive resin laminate for forming a resist pattern to form a metal pillar and a semiconductor bump, comprising a support film and a photosensitive resin layer containing a photosensitive resin composition, wherein the photosensitive resin composition contains, relative to the total solid content of the photosensitive resin composition, (A) 30% by mass to 70% by mass of an alkali-soluble polymer; (B) 20% by mass to 50% by mass of a compound having an ethylenically unsaturated bond; and (C) 0.01% by mass to 20% by mass of a photopolymerization initiator; and the component (B) contains at least: (B-1) a compound having a cyclic group, an ethylene oxide chain, and two acryloyl groups in one molecule; (12) A photosensitive resin laminate for forming a resist pattern for forming metal pillars and semiconductor bumps, wherein the mass ratio (methacrylate monomer / acrylate monomer) of the compound having a methacryloyl group to the compound having an acryloyl group in the component (B) is 0 or more and less than 0.5, and the thickness of the photosensitive resin layer is 80 μm or more. (13) The compound (B-1) is represented by the following general formula (II): {wherein each EO independently represents ethylene oxide, each A independently represents an acryloyl group, and m and n independently represent an integer of 1 to 100.} (13) The photosensitive resin laminate for forming a resist pattern for forming a metal pillar and a semiconductor bump according to item 11 or 12, wherein the mass ratio (methacrylate monomer / acrylate monomer) of the compound having a methacryloyl group to the compound having an acryloyl group in component (B) is less than 0.1. (14) The photosensitive resin laminate for forming a resist pattern for forming a metal pillar and a semiconductor bump according to any one of items 11 to 13, further comprising (B-2) a compound having three or more acryloyl groups as component (B). (15) The photosensitive resin laminate for forming a resist pattern for forming a metal pillar and a semiconductor bump according to any one of items 1 to 14, which is used in a step of stripping a resist pattern formed by exposing and developing the photosensitive resin laminate using a stripping solution containing no dimethyl sulfoxide.

[0013] According to the present disclosure, a photosensitive resin laminate is provided that can improve the removability of a resist pattern, and as a result, the solubility of peeled pieces of the resist pattern is improved even in the case of a thick photosensitive resin laminate, the stripping process time is significantly shortened, and stripping residue or plating penetration can be suppressed.

[0014] <Photosensitive Resin Laminate> The photosensitive resin laminate of the present disclosure includes a support film and a photosensitive resin layer laminated on the support film. The photosensitive resin laminate is preferably a dry film resist. The photosensitive resin layer may have a protective layer on the surface opposite to the support film side, as necessary. The photosensitive resin laminate of the present disclosure is also preferably used for forming a resist pattern for forming metal pillars and semiconductor bumps.

[0015] The photosensitive resin layer includes a photosensitive resin composition, and the photosensitive resin composition includes, relative to the total solid content of the photosensitive resin composition, (A) 30% to 70% by mass of an alkali-soluble polymer, (B) 20% to 50% by mass of a compound having an ethylenically unsaturated bond, and (C) 0.01% to 20% by mass of a photopolymerization initiator. Furthermore, the photosensitive resin layer may include, relative to the total solid content mass of the photosensitive resin layer, (A) 30% to 70% by mass of the alkali-soluble polymer, (B) 20% to 50% by mass of the compound having an ethylenically unsaturated bond, and (C) 0.01% to 20% by mass of the photopolymerization initiator. The photosensitive resin layer may optionally contain, in addition to the components (A) to (C), a polymer other than the component (A), a monomer other than the component (B), an initiator other than the component (C), and other components such as a dye, an antioxidant, a plasticizer, etc.

[0016] In the present disclosure, a photosensitive resin laminate capable of improving the releasability of a resist pattern is specified by optimizing the thickness of the photosensitive resin layer, the structure and content of each component contained therein, for example, the structure and content of component (B) and / or component (A), etc.

[0017] In one example of the present disclosure, a photosensitive resin laminate can be provided in which the composition of component (B) is specified. Specifically, component (B) may include at least two types of monomers, i.e., a bifunctional monomer and a trifunctional or higher polyfunctional monomer, or may include not only a bifunctional monomer but also a specified mass ratio (methacrylate monomer / acrylate monomer) of a compound having a methacryloyl group to a compound having an acryloyl group in component (B). These embodiments provide excellent resist pattern developability, resolution, and solubility in a stripper solution. The bifunctional monomer may be, for example, (B-1) a compound having a cyclic group, an ethylene oxide chain, and two acryloyl groups in one molecule. The polyfunctional monomer may be, for example, (B-2) a compound having three or more acryloyl groups.

[0018] In another example of the present disclosure, a photosensitive resin laminate can be provided that contains a bifunctional monomer as component (B) and in which the contents or configurations of components other than component (B) are specified. Specifically, the bifunctional monomer can include, for example, (B-1), a compound having a cyclic group, an ethylene oxide chain, and two acryloyl groups in one molecule, and the configuration of component (A) and / or the combination of component (A) and component (B) can be specified, which can contribute to improving resist pattern strippability.

[0019] Common configurations, preferred embodiments, and the like in this disclosure will be described below.

[0020] <(A) Alkali-Soluble Polymer> The photosensitive resin composition and photosensitive resin layer according to the present disclosure contain an alkali-soluble polymer. The amount of the alkali-soluble polymer is 30% by mass to 70% by mass, preferably 40% by mass to 70% by mass, and more preferably 50% by mass to 70% by mass, based on the total solids mass of the photosensitive resin composition or the photosensitive resin layer. In this specification, an alkali-soluble polymer refers to a polymer that can be dissolved in an alkaline aqueous solution.

[0021] The alkali-soluble polymer preferably contains a copolymer containing a monomer having an aromatic ring as a copolymerization component. Alkali-soluble polymers containing a monomer having an aromatic ring as a copolymerization component are hydrophobic and have a swelling suppression effect, and therefore provide excellent resolution of resist patterns. From the viewpoints of the swelling suppression effect and resolution, the mass ratio of the unit having an aromatic ring in the alkali-soluble polymer is preferably within the range of 50 to 90 mass%, more preferably 70 to 90 mass%, and even more preferably 75 to 85 mass%.

[0022] Examples of monomers having an aromatic ring include (meth)acrylates having an aromatic group; and aromatic vinyl compounds such as styrene and styrene derivatives. In this specification, (meth)acrylate means acrylate or methacrylate, (meth)acrylic means acrylic or methacrylic, and (meth)acryloyl means acryloyl or methacryloyl. Examples of styrene derivatives include oxystyrene, hydroxystyrene, acetoxystyrene, alkylstyrene, and halogenoalkylstyrene. Among these, (meth)acrylates having an aromatic group are preferred from the viewpoint of the developability of the resist pattern.

[0023] The aromatic group of the (meth)acrylate having an aromatic group is preferably an aromatic group having 6 to 20 carbon atoms, and examples thereof include a phenyl group, a benzyl group, a biphenyl group, and a naphthyl group. The hydrogen atom of the aromatic group may be unsubstituted or substituted, and when substituted, examples of the substituent include a hydrocarbon group having 1 to 5 carbon atoms, a hydroxyl group, a halogen group, etc.

[0024] The alkali-soluble polymer preferably contains a copolymer having benzyl (meth)acrylate as a copolymerization component as a (meth)acrylate having an aromatic group. Generally, aromatic rings are considered to have low developability due to their hydrophobicity, whereas benzyl (meth)acrylate is preferred because it has high flexibility and excellent developability.

[0025] The ratio of benzyl (meth)acrylate contained as a copolymerization component in the alkali-soluble polymer is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, based on the mass of all monomers constituting the alkali-soluble polymer. A high ratio of benzyl (meth)acrylate improves the stripping properties of the resist pattern. The amount of benzyl (meth)acrylate is preferably less than 100% by mass, more preferably 95% by mass or less, and even more preferably 90% by mass or less, based on the mass of all monomers constituting the alkali-soluble polymer.

[0026] The alkali-soluble polymer has an acid equivalent of 350 or more, preferably 370 or more, more preferably 380 or more, even more preferably 390 or more, still more preferably 400 or more, and particularly preferably 410 or more. The acid equivalent refers to the mass in grams of the alkali-soluble polymer per equivalent of carboxyl group. An acid equivalent of 350 or more has advantages such as shortening the minimum development time, improving resolution, reducing stripper fatigue, and preventing resist wrinkles during storage. The upper limit of the acid equivalent is not limited, but is preferably 600 or less, for example. An acid equivalent of 600 or less can improve developability and strippability.

[0027] The lower the proportion of acid groups in the alkali-soluble polymer, the more suppressed swelling can be and the more likely the resolution is to be excellent, so the proportion of acid groups is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, based on the solid content mass of the alkali-soluble polymer. The lower limit of the proportion of acid groups is not particularly limited, but may be, for example, 0% by mass, more than 0% by mass, or 1% by mass or more.

[0028] The lower the weight-average molecular weight of the alkali-soluble polymer, the better the developability and peeled-off fragment solubility tend to be. Therefore, the weight-average molecular weight is preferably less than 60,000, more preferably 50,000 or less, even more preferably 40,000 or less, and particularly preferably 30,000 or less. The lower limit of the weight-average molecular weight of the alkali-soluble polymer is preferably 5,000 or more, more preferably 6,000 or more, from the viewpoint of reducing development aggregates and improving the properties of the unexposed film in the photosensitive resin laminate, such as edge fuse property and cut-chip property. Edge fuse property refers to the property of suppressing the phenomenon in which the photosensitive resin layer protrudes from the edge of the roll when the photosensitive resin laminate is wound into a roll. Cut-chip property refers to the property of suppressing the phenomenon in which chips fly off when the unexposed film is cut with a cutter. Poor cut-chip property can cause scattered chips to adhere to, for example, the upper surface of the photosensitive resin laminate, and these chips may be transferred to a mask in a subsequent exposure process, causing defects.

[0029] The alkali-soluble polymer may contain a copolymerization component other than a monomer having an aromatic ring. Examples of such copolymerization components include carboxylic acids, carboxylates, and acid anhydrides having at least one polymerizable unsaturated group in the molecule, such as (meth)acrylic acid, fumaric acid, cinnamic acid, crotonic acid, itaconic acid, maleic anhydride, maleic acid half ester (meth)acrylic acid, alkyl (meth)acrylates; (meth)acrylonitrile, and (meth)acrylamide. Among these, it is preferable to contain a structural unit derived from (meth)acrylic acid as the copolymerization component. The total amount of methacrylic acid and acrylic acid in the alkali-soluble polymer is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, based on the solids mass of the alkali-soluble polymer.

[0030] The alkali-soluble polymer preferably contains a structural unit derived from methacrylic acid, since this provides excellent developability and a good balance with resolution. When methacrylic acid is contained in the alkali-soluble polymer, the proportion is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, based on the solid mass of the alkali-soluble polymer. The lower limit of the mass proportion of the structural unit derived from methacrylic acid in the alkali-soluble polymer is not limited, but may be, for example, 0% by mass or more.

[0031] The alkali-soluble polymer preferably contains a structural unit derived from acrylic acid, since the flexibility of the cured film or cured resist pattern is excellent, and thus the developability is excellent. From the viewpoint of flexibility and developability, the mass ratio of the structural unit derived from acrylic acid in the alkali-soluble polymer is preferably 20 mass% or less, more preferably 10 mass% or less, and even more preferably 5 mass% or less, based on the solid content mass of the alkali-soluble polymer. The lower limit of the mass ratio of the structural unit derived from acrylic acid in the alkali-soluble polymer is not limited, but may be, for example, 0 mass%, more than 0 mass%, or 1 mass% or more.

[0032] The alkali-soluble polymer preferably contains an alkyl group, because the resulting cured film or cured resist pattern has excellent flexibility and therefore excellent developability. From the viewpoints of flexibility and developability, the mass ratio of the structural units derived from alkyl group-containing monomers in the alkali-soluble polymer is preferably within a range of 1 to 20 mass%, more preferably 1 to 10 mass%, based on the solids mass of the alkali-soluble polymer.

[0033] The longer the alkyl chain of the alkali-soluble polymer, the more excellent the flexibility and developability tend to be. Therefore, the alkali-soluble polymer preferably contains an alkyl group having 1 to 10 carbon atoms, more preferably contains an alkyl group having 4 to 10 carbon atoms, and even more preferably contains an alkyl group having 6 to 10 carbon atoms.

[0034] The alkyl group of the alkyl (meth)acrylate may be linear, branched, or cyclic, and may have, for example, 1 or more, 2 or more, 3 or more, 4 or more, 5 or more, or 6 or more, and 12 or less, 11 or less, 10 or less, 9 or less, or 8 or less carbon atoms. More specific examples of the alkyl group of the alkyl (meth)acrylate include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, hexyl, heptyl, octyl, ethylhexyl, nonyl, decyl, undecyl, and dodecyl groups. Among these, 2-ethylhexyl is even more preferred from the viewpoints of shortening development time and reducing footing of the resist pattern. By using, for example, 2-ethylhexyl (meth)acrylate as part of the monomer used in synthesizing the alkali-soluble polymer, an alkali-soluble polymer containing 2-ethylhexyl acrylate as a copolymerization component can be obtained.

[0035] Preferred combinations of copolymerization components in the alkali-soluble polymer include, for example, (meth)acrylic acid and benzyl (meth)acrylate; (meth)acrylic acid, benzyl (meth)acrylate and an aromatic vinyl compound; and (meth)acrylic acid, benzyl (meth)acrylate and an alkyl (meth)acrylate. More specific examples include methacrylic acid and benzyl methacrylate; acrylic acid, benzyl methacrylate and styrene; and acrylic acid, benzyl methacrylate and 2-ethylhexyl acrylate.

[0036] (B) Compound Having an Ethylenically Unsaturated Bond The photosensitive resin composition and photosensitive resin layer according to the present disclosure contain a compound having an ethylenically unsaturated bond. The amount of the compound having an ethylenically unsaturated bond is 20% by mass to 50% by mass, preferably 20% by mass to 40% by mass, based on the total solids mass of the photosensitive resin composition or the photosensitive resin layer. The ethylenically unsaturated bond can be polymerized by irradiation with light in the presence of a photopolymerization initiator, thereby curing the photosensitive resin layer.

[0037] The compound having an ethylenically unsaturated bond may have a double bond equivalent of 150 or more, preferably 160 or more, more preferably 170 or more, even more preferably 180 or more, still more preferably 190 or more, and particularly preferably 200 or more. When the double bond equivalent is 150 or more, resistance to plating penetration and peelability tend to be improved. The upper limit of the double bond equivalent of the compound having an ethylenically unsaturated bond is not limited, but may be, for example, 500 or less, 400 or less, or 300 or less. In this specification, "double bond equivalent" means the molecular weight per ethylenically unsaturated bond.

[0038] From the viewpoint of improving resolution, the concentration of ethylenically unsaturated bonds in the photosensitive resin layer is preferably 1.0 mmol / g or more, more preferably 1.5 mmol / g or more, and even more preferably 2.0 mmol / g or more. When the concentration of ethylenically unsaturated bonds in the photosensitive resin layer is 1.0 mmol / g or more, a strong crosslinked film is formed as a resist pattern, there is a swelling suppression effect, and resolution tends to be excellent. The ethylenically unsaturated bonds in the photosensitive resin layer are preferably derived from at least ethylenically unsaturated methacryloyl groups or acryloyl groups. The upper limit of the concentration of ethylenically unsaturated bonds in the photosensitive resin layer is not limited, but may be, for example, 5.0 mmol / g or less, 3.0 mmol / g or less, or 2.0 mmol / g or less. In this specification, "the concentration of ethylenically unsaturated bonds in the photosensitive resin layer" means the total number of moles of ethylenically unsaturated groups per gram of the photosensitive resin layer.

[0039] As the compound having an ethylenically unsaturated bond, for example, a compound having a (meth)acryloyl group can be used. While not wishing to be bound by theory in the present disclosure, it is believed that the dissolution mechanism of a photosensitive resin laminate or a resist pattern in a stripping solution such as a tetraalkylammonium hydroxide aqueous solution is that the compound having an ethylenically unsaturated bond contained in the photosensitive resin layer is hydrolyzed, and the crosslinked portion of the photosensitive resin layer dissolves in the stripping solution while decomposing. Based on the above dissolution mechanism, a compound having an acryloyl group (acrylate monomer) is preferred because it has better hydrolysis properties than a compound having a methacryloyl group (methacrylate monomer), and the acrylate monomer is more easily dissolved and stripped in the stripping process.

[0040] Similar to the dissolution mechanism described above, from the viewpoint of the solubility of the resist pattern in the stripping solution, the mass ratio (methacrylate monomer / acrylate monomer) of the compound having a methacryloyl group to the compound having an acryloyl group in the compound having an ethylenically unsaturated bond is preferably 0 or more and less than 0.5, more preferably 0 or more and less than 0.1. Since acrylate monomers are more hydrolyzable than methacrylate monomers and tend to be easily decomposed in the stripping solution, it is preferable that the compound having an ethylenically unsaturated bond contains a larger amount of acrylate monomer than methacrylate monomer. Furthermore, it is preferable that the methacrylate monomer is not contained in the compound having an ethylenically unsaturated bond, or that it is contained in a mass ratio less than half that of the acrylate monomer.

[0041] Similar to the dissolution mechanism described above, from the viewpoints of stripping solution solubility and hydrolysis property, the ratio of the methacrylate monomer in the compound having an ethylenically unsaturated bond is preferably less than 50% by mass, more preferably 30% by mass, even more preferably less than 20% by mass, still more preferably less than 10% by mass, still more preferably less than 5% by mass, particularly preferably less than 3% by mass, and most preferably 0% by mass, based on the mass of the compound having an ethylenically unsaturated bond.

[0042] The compound having an ethylenically unsaturated bond can be optionally modified with alkylene oxide, specifically, can have one or more alkylene oxide chains in the molecule. Examples of alkylene oxide include methylene oxide (MO), ethylene oxide (EO), propylene oxide (PO), trimethylene oxide, butylene oxide (BO), and tetramethylene oxide.

[0043] As these alkylene oxides, ethylene oxide (EO) having 2 carbon atoms or alkylene oxides having 3 or more carbon atoms are likely to be used. As alkylene oxides having 3 or more carbon atoms, propylene oxide (PO) or butylene oxide (BO) are particularly likely to be used. The number of carbon atoms in alkylene oxides having 3 or more carbon atoms may be, for example, 6 or less, 5 or less, or 4 or less.

[0044] Specifically, the structures of ethylene oxide (EO), propylene oxide (PO), trimethylene oxide, butylene oxide (BO) and tetramethylene oxide, and the raw material compounds thereof may be as exemplified below.

[0045] Since a compound having an ethylenically unsaturated bond with a relatively hydrophilic side chain tends to have good solubility in a stripping solution containing a large amount of water or a hydrophilic solvent, the alkylene oxide chain contained in the compound is preferably relatively hydrophilic. That is, as a compound (monomer) having an alkylene oxide-modified ethylenically unsaturated bond, an EO-modified monomer is preferred compared to a monomer modified with an alkylene oxide having 3 or more carbon atoms. Therefore, from the viewpoint of solubility in the stripping solution, the mass ratio of the monomer modified with an alkylene oxide having 3 or more carbon atoms to the EO-modified monomer ((monomer modified with an alkylene oxide having 3 or more carbon atoms) / EO-modified monomer) is preferably 0 or more and less than 0.1. A monomer not having an alkylene oxide chain is counted as an EO-modified monomer.

[0046] Furthermore, with regard to EO-modification, PO-modification, and BO-modification, EO-modification is preferred compared to the relatively hydrophobic PO-modification and BO-modification. Furthermore, the mass ratio of the PO- or BO-modified monomer to the EO-modified monomer in the compound having an ethylenically unsaturated bond ((PO-modified monomer + BO-modified monomer) / EO-modified monomer) is preferably 0 or more and less than 0.1 from the viewpoint of solubility in the stripping solution. Monomers without alkylene oxide chains are calculated as EO-modified monomers. From the same viewpoint, the ratio of the PO monomer and / or BO monomer in the compound having an ethylenically unsaturated bond is preferably 30% by mass or less, more preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and particularly preferably 0% by mass, based on the total solids mass of the compound having an ethylenically unsaturated bond.

[0047] Regarding the EO chain length of a compound having an ethylenically unsaturated bond, the shorter the chain length, the better the resolution, whereas the longer the chain length, the better the developability. The number of moles of EO units in a compound having an ethylenically unsaturated bond is preferably within a range of 1 to 30, more preferably 4 to 20, and even more preferably 4 to 10, per mole of the compound, from the viewpoint of the balance between resolution and developability. When the number of moles of EO units exceeds 1, the compound having an ethylenically unsaturated bond contains a repeating unit having an EO chain.

[0048] The number of functional groups in a compound having an ethylenically unsaturated bond tends to be higher as the number increases, while the number of functional groups tends to be higher as the number decreases, so the number can be determined based on the balance between resolution and releasability. The number of functional groups in a compound having an ethylenically unsaturated bond may be, for example, monofunctional (hereinafter also referred to as monofunctional), difunctional or more, trifunctional or more, tetrafunctional or more, pentafunctional or more, hexafunctional or more, trifunctional to 10functional, trifunctional to hexafunctional, or tetrafunctional to hexafunctional, or a combination of multiple compounds with different numbers of functional groups. In this specification, the "number of functional groups" refers to the number of ethylenically unsaturated bonds per molecule of a compound. For example, in the case of an acrylate monomer, it is defined as the number of acryloyl groups per molecule, and in the case of a methacrylate monomer, it is defined as the number of methacryloyl groups per molecule.

[0049] Compounds having a monofunctional ethylenic double bond are preferred because they have excellent solubility in the stripping solution. Examples of compounds having a monofunctional ethylenic double bond include compounds in which (meth)acrylic acid is added to one end of a (poly)alkylene glycol; and compounds in which (meth)acrylic acid is added to one end of a (poly)alkylene glycol and a group without an ethylenic double bond, such as an alkyl group, is added to the other end. The alkylene group in the (poly)alkylene glycol is preferably an alkylene group having 2 to 10 carbon atoms, more preferably 2 to 4 carbon atoms, such as a 1,2-ethylene group, a 1,2-propylene group, or a butylene group. From the viewpoint of solubility in the stripping solution, the content of the monofunctional monomer in the compound having an ethylenic double bond is preferably within the range of 1 to 30 mass%, more preferably 1 to 20 mass%, and even more preferably 5 to 15 mass%, based on the total solids mass of the compound having an ethylenically unsaturated bond.

[0050] Examples of bifunctional or higher functional compounds include compounds having a structure in which a skeleton of (poly)alkylene glycol, bisphenol A, trimethylolpropane, glycerin, pentaerythritol, dipentaerythritol, or the like is used, and at least two or all of the hydrogen atoms of the hydroxyl groups in the skeleton are substituted with functional groups having an ethylenically unsaturated bond, preferably functional groups having a (meth)acryloyl group, and more preferably functional groups having an acryloyl group.

[0051] The compound having a (poly)alkylene glycol skeleton and a bifunctional ethylenically unsaturated bond includes compounds represented by the following general formula (I): In the formula, each Y independently represents an alkylene group; １ and R ２ each independently represents a methyl group or a hydrogen atom, and each n independently represents an integer of 1 to 50.

[0052] In the general formula (I), each Y is independently an alkylene group preferably having 2 to 10 carbon atoms, more preferably 2 to 4 carbon atoms, such as a 1,2-ethylene group, a 1,2-propylene group, or a butylene group. The (Y-O) moiety may contain repeating units of different alkylene oxides, or may consist of repeating units of the same alkylene oxide. When the (Y-O) moiety contains different alkylene oxides, the arrangement may be random, alternating, or block. n represents an integer of 1 to 50, preferably 3 to 20, and more preferably 6 to 10.

[0053] More specific examples of the compound represented by the general formula (I) include: diacrylate of hexaethylene glycol, diacrylate of heptaethylene glycol, diacrylate of octaethylene glycol, diacrylate of nonaethylene glycol, diacrylate of decaethylene glycol, diacrylate of hexapropylene glycol, diacrylate of heptapropylene glycol, diacrylate of octapropylene glycol, diacrylate of nonapropylene glycol, and diacrylate of decapropylene glycol.

[0054] The double bond equivalent of the (meth)acrylate monomer represented by the general formula (I) is preferably 150 or more, more preferably 160 or more, even more preferably 170 or more, and still more preferably 180 or more, from the viewpoints of resistance to plating penetration, stripper solution processability, and stripper solution fatigue resistance, and is optionally 500 or less, 400 or less, or 300 or less.

[0055] In one example of the present disclosure, the bifunctional monomer is preferably a compound (B-1) having a cyclic group, an ethylene oxide (EO) chain, and two acryloyl groups in one molecule. When the photosensitive resin composition or photosensitive resin layer contains the compound (B-1), it tends to have excellent developability, resolution, and stripper solubility. Furthermore, when the compound (B-1) has a cyclic group, it tends to have improved resistance to plating penetration. In the compound (B-1), the cyclic group may be single or multiple, the EO chain may be located on one side or both sides of the cyclic group, and the two acryloyl groups may be located in any positions.

[0056] The EO chains of the compound (B-1) are preferably located on both sides of the cyclic group, since the higher the content ratio of the EO chains, the better the solubility in a stripping solution containing a large amount of water or a hydrophilic solvent. From the viewpoint of the balance between resolution and developability, the number of moles of the EO chains of the compound (B-1) is preferably within a range of 1 to 30, more preferably 4 to 20, and even more preferably 4 to 10.

[0057] An example of the compound (B-1) is a compound having a skeleton of hydrogenated bisphenol A, both sides of which are EO-modified, and which has acryloyl groups at both ends. Hydrogenated bisphenol A is a compound in which hydrogen is added to the aromatic ring of bisphenol A.

[0058] The (B-1) compound is preferably a compound in which the cyclic group is an aromatic ring. That is, the (B-) compound is preferably a compound having an aromatic ring, an ethylene oxide (EO) chain, and two acryloyl groups in one molecule. When the cyclic group is an aromatic ring, resistance to plating penetration tends to be further improved. Examples of such compounds include compounds having a bisphenol A skeleton, both sides of the bisphenol A skeleton being EO-modified, and having acryloyl groups at both ends. The bisphenol A skeleton in the (B-1) compound not only improves the strength of the crosslinked film, but also improves resolution.

[0059] The compound having a bisphenol A skeleton, both ends of which are EO-modified, and both ends of which have acryloyl groups is preferably a diacrylate of ethylene oxide (EO)-modified bisphenol A. The diacrylate of ethylene oxide-modified bisphenol A is preferably a diacrylate of ethylene oxide-modified bisphenol A represented by the following general formula (II): {wherein each EO independently represents ethylene oxide, each A independently represents an acryloyl group, and m and n independently represent an integer of 1 to 100. In formula (II), from the viewpoint of improving the strippability of the resist pattern, m and n preferably satisfy the relationship 5≦m+n≦20, more preferably 7≦m+n≦15, even more preferably 8≦m+n≦12, and particularly preferably m+n≈10.

[0060] More specific examples of the compound represented by the general formula (II) include: diacrylates of polyethylene glycol having an average of 1 mole of ethylene oxide added to each end of bisphenol A, diacrylates of polyethylene glycol having an average of 2 moles of ethylene oxide added to each end of bisphenol A, diacrylates of polyethylene glycol having an average of 3 moles of ethylene oxide added to each end of bisphenol A, diacrylates of polyethylene glycol having an average of 4 moles of ethylene oxide added to each end of bisphenol A, diacrylates of polyethylene glycol having an average of 5 moles of ethylene oxide added to each end of bisphenol A, diacrylates of polyethylene glycol having an average of 6 to 9 moles of ethylene oxide added to each end of bisphenol A, diacrylates of polyethylene glycol having an average of 10 moles of ethylene oxide added to each end of bisphenol A, diacrylates of polyethylene glycol having an average of 11 to 19 moles of ethylene oxide added to each end of bisphenol A, Examples include diacrylates of polyethylene glycol in which an average of 20 moles of ethylene oxide have been added to each end of bisphenol A, diacrylates of polyethylene glycol in which an average of 21 to 29 moles of ethylene oxide have been added to each end of bisphenol A, diacrylates of polyethylene glycol in which an average of 30 moles of ethylene oxide have been added to each end of bisphenol A, and diacrylates of polyethylene glycol in which an average of 31 moles or more of ethylene oxide have been added to each end of bisphenol A.

[0061] The double bond equivalent of the compound represented by the general formula (II) is preferably 150 or more, more preferably 160 or more, even more preferably 170 or more, and still more preferably 180 or more, from the viewpoints of resistance to plating penetration, stripper solution processability, and stripper solution fatigue resistance, and is optionally 500 or less, 400 or less, or 300 or less.

[0062] In one example of the present disclosure, the photosensitive resin composition or the photosensitive resin layer preferably contains a tri- or higher functional monomer as the compound having an ethylenically unsaturated bond.

[0063] In another example of the present disclosure, as the compound having an ethylenically unsaturated bond, at least two types of monomers are preferred, and a combination of a bifunctional monomer and a trifunctional or higher polyfunctional monomer is more preferred.

[0064] As the tri- or higher functional monomer, a compound (B-2) having three or more acryloyl groups is preferred. When the photosensitive resin composition or the photosensitive resin layer contains the (B-2) compound, the photosensitive resin composition or the photosensitive resin layer tends to have excellent developability, resolution, and stripping solution solubility. As the (B-2) compound, for example, among the tri- or higher functional monomers described below, one having an acryloyl group as the group having an ethylenically unsaturated bond may be used.

[0065] Examples of compounds having a trimethylolpropane skeleton and a trifunctional ethylenically unsaturated bond include compounds represented by the following general formula (III): {wherein n1, n2, and n3 each independently represent an integer of 1 to 25, provided that n1 + n2 + n3 is an integer of 3 to 75, and R1, R2, and R3 each independently represent a methyl group or a hydrogen atom}

[0066] In the general formula (III), n1, n2, and n3 are each independently an integer of 1 to 25, preferably 1 to 10, and more preferably 1 to 3. n1 + n2 + n3 is an integer of 3 to 75, preferably 3 to 30, more preferably 3 to 15, and even more preferably 3 to 9. n1 + n2 + n3 being 9 or greater is preferred from the viewpoints of suppressing the occurrence of resist tails, improving film strength, and imparting flexibility to the cured film. n1 + n2 + n3 being 75 or less is preferred from the viewpoints of high resolution and adhesion, good release properties, and controlling edge fusing properties.

[0067] Specific examples of the compound represented by the general formula (III) include: a triacrylate in which an average of 3 moles of ethylene oxide in total has been added to the hydroxyl terminals of trimethylolpropane, a triacrylate in which an average of 9 moles of ethylene oxide in total has been added to the hydroxyl terminals of trimethylolpropane, a triacrylate in which an average of 15 moles of ethylene oxide in total has been added to the hydroxyl terminals of trimethylolpropane, and a triacrylate in which an average of 30 moles of ethylene oxide in total has been added to the hydroxyl terminals of trimethylolpropane.

[0068] The double bond equivalent of the (meth)acrylate monomer represented by the general formula (III) is preferably 150 or more, more preferably 160 or more, even more preferably 170 or more, and still more preferably 180 or more, from the viewpoints of resistance to plating penetration, stripper solution processability, and stripper solution fatigue resistance, and is optionally 500 or less, 400 or less, or 300 or less.

[0069] Examples of compounds having a glycerin skeleton and a trifunctional ethylenically unsaturated bond include compounds represented by the following formula (IV): {wherein each Y independently represents an alkylene group, each R independently represents a methyl group or a hydrogen atom, and each n independently represents an integer of 0 to 200}.

[0070] In general formula (IV), each Y is independently an alkylene group preferably having 2 to 10 carbon atoms, more preferably 2 to 4 carbon atoms, such as a 1,2-ethylene group, a 1,2-propylene group, or a butylene group. From the viewpoints of imparting flexibility to the cured film, improving film strength, suppressing development aggregation, and increasing the reactivity of the ethylenically unsaturated bonds, it is preferable that at least one or all of the Ys be a 1,2-ethylene group. The (Y-O) moiety may contain repeating units of different alkylene oxides, or may be composed of repeating units of the same alkylene oxide. When the (Y-O) moiety contains different alkylene oxides, the arrangement thereof may be random, alternating, or block. Each n is independently an integer from 0 to 200. Preferably, at least one n is an integer from 1 to 200, and more preferably, three n's are integers from 1 to 200. In general formula (VI), n may be 0, i.e., no alkylene oxide moiety may be present. When the total number of n's is 1 or more, it is preferable from the viewpoints of suppressing the occurrence of a resist base, improving film strength, and imparting flexibility to the cured film. When the total number of n's is 200 or less, it is preferable from the viewpoints of high resolution and adhesion, good release properties, and controlling edge fusing properties.

[0071] The double bond equivalent of the (meth)acrylate monomer represented by the general formula (IV) is preferably 150 or more, more preferably 160 or more, even more preferably 170 or more, and still more preferably 180 or more, from the viewpoints of resistance to plating penetration, stripper solution processability, and stripper solution fatigue resistance, and is optionally 500 or less, 400 or less, or 300 or less.

[0072] As the compound having a pentaerythritol skeleton and a tetrafunctional ethylenically unsaturated bond, there can be mentioned a compound represented by the following general formula (V): {In the formula, n １ , n ２ , n ３ and n ４ each independently represents an integer of 1 to 25; １ +n ２ +n ３ +n ４ is an integer from 4 to 100, and R １, R ２ , R ３ and R ４ each independently represents a methyl group or a hydrogen atom, R ５ , R ６ , R ７ , and R ８ each independently represents an alkylene group; R ５ , R ６ , R ７ and R ８ When there are a plurality of R ５ , R ６ , R ７ and R ８ may be the same or different).

[0073] In general formula (V), R ５ , R ６ , R ７ and R ８ are each independently an alkylene group preferably having 2 to 10 carbon atoms, more preferably 2 to 4 carbon atoms, such as a 1,2-ethylene group, a 1,2-propylene group, or a butylene group. From the viewpoints of imparting flexibility to the cured film, improving film strength, suppressing development aggregation, and increasing the reactivity of the ethylenically unsaturated bond, R ５ , R ６ , R ７ and R ８ Preferably, at least one or all of n is a 1,2-ethylene group. １ +n ２ +n ３ +n ４ is 4 to 100, preferably 4 to 80, more preferably 4 to 40, even more preferably 4 to 20, and particularly preferably 4 to 16. １ +n ２ +n ３ +n ４ When n is 4 or more, it is preferable from the viewpoints of suppressing the occurrence of a resist skirt, improving film strength, and imparting flexibility to the cured film. １ +n ２ +n ３ +n ４When the value is 100 or less, it is preferable from the viewpoint of high resolution and adhesion, good peeling properties, and controlling edge fusing properties.

[0074] Specific examples of the compound represented by the general formula (V) include: a tetraacrylate in which an average of 4 moles of ethylene oxide have been added to the hydroxyl terminals of pentaerythritol, a tetraacrylate in which an average of 9 moles of ethylene oxide have been added to the hydroxyl terminals of pentaerythritol, a tetraacrylate in which an average of 12 moles of ethylene oxide have been added to the hydroxyl terminals of pentaerythritol, a tetraacrylate in which an average of 15 moles of ethylene oxide have been added to the hydroxyl terminals of pentaerythritol, a tetraacrylate in which an average of 20 moles of ethylene oxide have been added to the hydroxyl terminals of pentaerythritol, a tetraacrylate in which an average of 28 moles of ethylene oxide have been added to the hydroxyl terminals of pentaerythritol, and a tetraacrylate in which an average of 35 moles of ethylene oxide have been added to the hydroxyl terminals of pentaerythritol.

[0075] The double bond equivalent of the (meth)acrylate monomer represented by the general formula (V) is preferably 150 or more, more preferably 160 or more, even more preferably 170 or more, and still more preferably 180 or more, from the viewpoints of resistance to plating penetration, stripper solution processability, and stripper solution fatigue resistance, and is optionally 500 or less, 400 or less, or 300 or less.

[0076] Among the compounds having a pentaerythritol skeleton and a tetrafunctional ethylenically unsaturated bond, the compound (B-2) is a compound represented by the following general formula (V1): {wherein each EO independently represents ethylene oxide, each A independently represents an acryloyl group, and k, l, m, and n independently represent an integer of 1 to 100} is preferred. The compound represented by general formula (V1) can improve the crosslinking density, thereby contributing to good resolution. From the viewpoint of improving the strippability of the resist pattern, k, l, m, and n in general formula (V1) preferably satisfy the relationship 4≦k+l+m+n≦100, more preferably 10≦k+l+m+n≦50, even more preferably 12≦k+l+m+n≦25, and particularly preferably k+l+m+n≈15.

[0077] Examples of the compound having a dipentaerythritol skeleton and a hexafunctional ethylenically unsaturated bond include compounds represented by the following general formula (VI): {wherein each R independently represents a methyl group or a hydrogen atom, and each n independently represents an integer of 0 to 30.} In general formula (VI), n may be 0, i.e., an alkylene oxide moiety may not be present.

[0078] In general formula (VI), n's are each independently an integer of 0 to 30, preferably 1 to 20, more preferably 2 to 10, and even more preferably 3 to 5. The total of n's is 0 to 180, preferably 6 to 120, more preferably 12 to 60, and even more preferably 18 to 30. A total of n's of 1 or more is preferred from the viewpoints of suppressing the occurrence of resist tails, improving film strength, and imparting flexibility to the cured film. A total of n's of 180 or less is preferred from the viewpoints of high resolution and adhesion, good release properties, and controlling edge fusing properties.

[0079] Specific examples of the hexaacrylate compound represented by general formula (VI) include dipentaerythritol hexaacrylate, a hexaacrylate having 1 to 36 moles of ethylene oxide added to the six terminals of dipentaerythritol in total, a hexaacrylate having 6 to 30 moles of ethylene oxide added to the six terminals of dipentaerythritol in total, a hexaacrylate having 12 to 30 moles of ethylene oxide added to the six terminals of dipentaerythritol in total, a hexaacrylate having 18 to 30 moles of ethylene oxide added to the six terminals of dipentaerythritol in total, and a hexaacrylate having 1 to 10 moles of ε-caprolactone added to the six terminals of dipentaerythritol in total.

[0080] The double bond equivalent of the (meth)acrylate monomer represented by the general formula (VI) is preferably 150 or more, more preferably 160 or more, even more preferably 170 or more, and still more preferably 180 or more, from the viewpoints of resistance to plating submersion, stripper treatment ability, and stripper fatigue resistance, and is optionally 500 or less, 400 or less, or 300 or less.

[0081] The higher the mass ratio (A / B) of the alkali-soluble polymer to the compound having an ethylenically unsaturated bond, the more improved the curing property of the bottom of the resist film and the more excellent the stripper solution fatigue resistance and resolution tend to be, while the lower the mass ratio, the more excellent the developability tends to be. From the viewpoint of the balance between resolution and developability, the mass ratio (A / B) is preferably within the range of 1.2 to 3.0, more preferably 1.5 to 2.5, even more preferably 1.7 to 2.5, still more preferably 1.8 to 2.3, and particularly preferably 1.8 to 2.2.

[0082] <(C) Photopolymerization Initiator> The photopolymerization initiator is a compound that can initiate polymerization of a compound having an ethylenically unsaturated bond by irradiating the compound with light in the presence of the compound.

[0083] The amount of photopolymerization initiator in the photosensitive resin composition and the photosensitive resin layer is 0.01% by mass to 20% by mass, preferably 0.3% by mass to 10% by mass, and more preferably 1% by mass to 5% by mass, based on the total solids mass of the photosensitive resin composition and the photosensitive resin layer, respectively. When the amount of photopolymerization initiator is 0.01% by mass or more, an exposure pattern with a sufficient residual film rate after development can be obtained. When the amount of photopolymerization initiator is 20% by mass or less, light can be sufficiently transmitted to the bottom surface of the resist, high resolution can be obtained, and development aggregation in the developer can be suppressed.

[0084] Examples of the photopolymerization initiator include imidazole compounds, aromatic ketones, acridine compounds, and N-aryl-α-amino acid compounds. One type of photopolymerization initiator may be used alone, or two or more types may be used in combination.

[0085] Imidazole compounds tend to improve the plating penetration resistance and suppress footing of resist patterns. Examples of the imidazole compound include imidazoles having an aliphatic group, such as methylimidazole, 2-ethyl-4-methylimidazole, 1-isobutyl-2-methylimidazole, 2-ethyl-4-methylimidazole, ethylimidazole, isopropylimidazole, 2,4-dimethylimidazole, undecylimidazole, and heptadecylimidazole; and imidazoles having an aromatic group, such as 1-benzyl-2-methylimidazole, phenylimidazole (e.g., 2-phenylimidazole), 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, triarylimidazole, and dimers thereof. Among these, from the viewpoint of plating resistance and suppressing plating penetration, imidazoles having an aromatic group are preferred, triarylimidazole (for example, lophine) or a dimer thereof is more preferred, and triarylimidazole dimer is even more preferred.

[0086] Examples of the triarylimidazole dimer include 2,4,5-triarylimidazole dimers such as 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, 2-(o-chlorophenyl)-4,5-di(methoxyphenyl)imidazole dimer, 2-(o-fluorophenyl)-4,5-diphenylimidazole dimer, 2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer, and 2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer.

[0087] Aromatic ketones are preferred from the viewpoint of improving sensitivity. Examples of aromatic ketones include benzophenone, N,N'-tetramethyl-4,4'-dimethylaminobenzophenone (Michler's ketone), N,N'-tetraethyl-4,4'-diaminobenzophenone, 4-methoxy-4'-dimethylaminobenzophenone, 4,4'-bis(diethylamino)benzophenone, 2-benzyl-2-dimethylamino-1-(4-monophornophenyl)-butanone-1, and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propanone-1. Of these, 4,4'-bis(diethylamino)benzophenone is preferred.

[0088] Acridine compounds are preferred from the viewpoints of improving sensitivity and achieving both high sensitivity and suppression of footing. Examples of acridine compounds include 1,7-bis(9,9'-acridinyl)heptane, 9-phenylacridine, 9-methylacridine, 9-ethylacridine, 9-chloroethylacridine, 9-methoxyacridine, 9-ethoxyacridine, 9-(4-methylphenyl)acridine, 9-(4-ethylphenyl)acridine, 9-(4-n-propylphenyl)acridine, 9-(4-n-butylphenyl)acridine, 9-(4-tert-butylphenyl)acridine, 9-(4-methoxyphenyl)acridine, 9-(4-ethoxyphenyl)acridine, and 9-(4-acetylphenyl)acridine. 9-(2-pyridyl)acridine, 9-(3-pyridyl)acridine, and 9-(4-pyridyl)acridine. Among these, 1,7-bis(9,9'-acridinyl)heptane and 9-phenylacridine are preferred in terms of sensitivity, resolution, availability, etc.

[0089] N-aryl-α-amino acid compounds are preferred from the viewpoint of improving sensitivity. Examples of N-aryl-α-amino acid compounds include N-phenylglycine, N-methyl-N-phenylglycine, and N-ethyl-N-phenylglycine.

[0090] Further examples of the photopolymerization initiator include quinones such as 2-ethylanthraquinone, phenanthrenequinone, 2-tert-butylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2,3-benzanthraquinone, 2-phenylanthraquinone, 2,3-diphenylanthraquinone, 1-chloroanthraquinone, 2-methylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthraquinone, 2-methyl-1,4-naphthoquinone, and 2,3-dimethylanthraquinone; benzoin ether compounds such as benzoin methyl ether, benzoin ethyl ether, and benzoin phenyl ether; benzil derivatives such as benzil methyl ketal; coumarin compounds; Pyrazoline derivatives such as 1-phenyl-3-(4-tert-butyl-styryl)-5-(4-tert-butyl-phenyl)-pyrazoline, 1-phenyl-3-(4-biphenyl)-5-(4-tert-butyl-phenyl)-pyrazoline, and 1-phenyl-3-(4-biphenyl)-5-(4-tert-octyl-phenyl)-pyrazoline; and the like.

[0091] Among these, it is preferable to contain a triarylimidazole dimer as the photopolymerization initiator. When a triarylimidazole dimer is contained as the photopolymerization initiator, the content of the triarylimidazole dimer in the photosensitive resin composition is preferably 0.3% by mass to 10% by mass, and more preferably 1% by mass to 5% by mass, based on the total solid content mass of the photosensitive resin composition or the photosensitive resin layer.

[0092] When the content of the triarylimidazole dimer in the photosensitive resin composition is within the above range, the content of the other photopolymerization initiator is preferably 0% by mass or more and 0.20% by mass or less, and more preferably 0% by mass or more and 0.10% by mass or less.

[0093] <Dye> The photosensitive resin composition and the photosensitive resin layer may each further contain a dye. The dye may contain at least one selected from leuco dyes, fluoran dyes, and other coloring substances. When the photosensitive resin layer contains these components, the exposed portions develop color, improving visibility. Furthermore, when an inspection machine or the like reads the alignment marker for exposure, the contrast between the exposed and unexposed portions is increased, making them easier to recognize.

[0094] Examples of leuco dyes include tris(4-dimethylaminophenyl)methane [leuco crystal violet], bis(4-dimethylaminophenyl)phenylmethane [leucomalachite green], etc. From the viewpoint of obtaining good contrast, leuco crystal violet is preferred as the leuco dye.

[0095] Examples of fluoran dyes include 2-(dibenzylamino)fluoran, 2-anilino-3-methyl-6-diethylaminofluoran, 2-anilino-3-methyl-6-dibutylaminofluoran, 2-anilino-3-methyl-6-N-ethyl-N-isoamylaminofluoran, 2-anilino-3-methyl-6-N-methyl-N-cyclohexylaminofluoran, 2-anilino-3-chloro-6-diethylaminofluoran, 2-anilino-3-methyl-6-N-ethyl-N-isoamylaminofluoran, 2-anilino-3-methyl-6-N-methyl-N-cyclohexylaminofluoran, 2-anilino-3-chloro-6-diethylaminofluoran, 2-anilino-3-methyl-6-N-ethyl-N-isobutylaminofluoran, 2-anilino-6-dibutylaminofluoran, 2-anilino-3-methyl-6-N-ethyl-N-tetrahydrofurfurylaminofluoran, 2-anilino-3-methyl-6-piperidinoaminofluoran, 2-(o-chloroanilino)-6-diethylaminofluoran, and 2-(3,4-dichloroanilino)-6-diethylaminofluoran.

[0096] The amount of the leuco dye or fluoran dye in the photosensitive resin composition and the photosensitive resin layer is preferably 0.1% by mass to 10% by mass, more preferably 0.2% by mass to 5% by mass, and even more preferably 0.3% by mass to 1% by mass, based on the total solids mass of the photosensitive resin composition and the photosensitive resin layer, respectively. When the amount of the dye is 0.1% by mass or more, the contrast between exposed and unexposed areas tends to be improved. When the amount of the dye is 10% by mass or less, the storage stability of the photosensitive resin layer tends to be improved, and the generation of aggregates during development tends to be suppressed.

[0097] Examples of coloring substances include fuchsin, phthalocyanine green, auramine base, paramagienta, crystal violet, methyl orange, Nile blue 2B, malachite green (manufactured by Hodogaya Chemical Co., Ltd., Eizen (registered trademark) MALACHITE GREEN), basic blue 7 (e.g., Eizen (registered trademark) Victoria Pure Blue BOH conc.), basic blue 20, and diamond green (manufactured by Hodogaya Chemical Co., Ltd., Eizen (registered trademark) DIAMOND GREEN GH).

[0098] The amount of the coloring substance in the photosensitive resin composition and the photosensitive resin layer is preferably 0.001% by mass to 1% by mass based on the total solid mass of the photosensitive resin composition and the photosensitive resin layer, respectively. When the amount of the coloring substance is 0.001% by mass or more, contrast tends to be improved, and when it is 1% by mass or less, storage stability tends to be improved.

[0099] <Halogen Compound> The photosensitive resin composition and the photosensitive resin layer may each further contain a halogen compound, and preferably contain a halogen compound in combination with the leuco dye. The combination of a leuco dye and a halogen compound tends to improve adhesion and contrast.

[0100] Examples of halogen compounds include amyl bromide, isoamyl bromide, isobutylene bromide, ethylene bromide, diphenylmethyl bromide, benzyl bromide, methylene bromide, tribromomethylphenylsulfone, carbon tetrabromide, tris(2,3-dibromopropyl)phosphate, trichloroacetamide, amyl iodide, isobutyl iodide, 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane, and chlorinated triazine compounds. Among these, tribromomethylphenylsulfone is preferred. Halogen compounds such as tribromomethylphenylsulfone are highly effective when used in combination with an acridine compound as a photopolymerization initiator, and are preferred from the standpoints of improving resolution, adhesion, sensitivity, contrast, tent film puncture resistance, suppressing resist footing, and etching resistance.

[0101] From the above viewpoints, the content of the halogen compound in the photosensitive resin composition and the photosensitive resin layer is preferably 0.01% by mass based on the total solid mass of the photosensitive resin composition and the photosensitive resin layer, respectively. This content is more preferably 0.1% by mass or more, even more preferably 0.3% by mass or more, and particularly preferably 0.5% by mass or more. Furthermore, it is preferable that this content be 3% by mass or less from the viewpoints of maintaining the storage stability of the hue in the photosensitive layer and suppressing the generation of aggregates during development. This content is more preferably 2% by mass or less, even more preferably 1.5% by mass or less.

[0102] <Antioxidant> The photosensitive resin composition and the photosensitive resin layer may each further contain an antioxidant. The antioxidant can improve the thermal stability and storage stability of the photosensitive resin layer. The antioxidant is preferably at least one compound selected from the group consisting of dicarboxylic polymerization inhibitors, benzotriazoles, and carboxybenzotriazoles.

[0103] Examples of the radical polymerization inhibitor include p-methoxyphenol, hydroquinone, pyrogallol, naphthylamine, tert-butylcatechol, phenothiazine, biphenol, cuprous chloride, 2,6-di-tert-butyl-p-cresol, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 4,4'-thiobis(6-tert-butyl-m-cresol), 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, styrenated phenol (for example, trade name "ANTAGE SP" manufactured by Kawaguchi Chemical Industry Co., Ltd.), tribenzylphenol (for example, trade name "TBP" manufactured by Kawaguchi Chemical Industry Co., Ltd., a phenol compound having 1 to 3 benzyl groups), and diphenylnitrosamine.

[0104] Examples of benzotriazoles include 1,2,3-benzotriazole, 1-chloro-1,2,3-benzotriazole, bis(N-2-ethylhexyl)aminomethylene-1,2,3-benzotriazole, bis(N-2-ethylhexyl)aminomethylene-1,2,3-tolyltriazole, and bis(N-2-hydroxyethyl)aminomethylene-1,2,3-benzotriazole.

[0105] Examples of carboxybenzotriazoles include 4-carboxy-1,2,3-benzotriazole, 5-carboxy-1,2,3-benzotriazole, N-(N,N-di-2-ethylhexyl)aminomethylenecarboxybenzotriazole, N-(N,N-di-2-hydroxyethyl)aminomethylenecarboxybenzotriazole, N-(N,N-di-2-ethylhexyl)aminoethylenecarboxybenzotriazole, and mixtures thereof. Among these, a mixture of 4-carboxy-1,2,3-benzotriazole and 5-carboxy-1,2,3-benzotriazole is preferred, with the mixing ratio being preferably about 1:1 by mass.

[0106] The total content of the antioxidant is preferably 0.01% by mass to 3% by mass, and more preferably 0.05% by mass to 1% by mass, based on the total solids mass of the photosensitive resin composition or the photosensitive resin layer. When the amount of the antioxidant is 0.01% by mass or more, the storage stability of the photosensitive resin layer is improved, and when it is 3% by mass or less, sensitivity tends to be maintained and decolorization of the dye tends to be suppressed.

[0107] <Plasticizer> The photosensitive resin composition or the photosensitive resin layer may contain a plasticizer as needed. Examples of the plasticizer include glycol esters such as polyethylene glycol, polypropylene glycol, polyoxypropylene polyoxyethylene ether, polyoxyethylene monomethyl ether, polyoxypropylene monomethyl ether, polyoxyethylene polyoxypropylene monomethyl ether, polyoxyethylene monoethyl ether, polyoxypropylene monoethyl ether, and polyoxyethylene polyoxypropylene monoethyl ether; phthalate esters such as diethyl phthalate; o-toluenesulfonic acid amide, p-toluenesulfonic acid amide, tributyl citrate, triethyl citrate, triethyl acetylcitrate, tri-n-propyl acetylcitrate, and tri-n-butyl acetylcitrate; propylene glycol in which propylene oxide is added to both terminals of bisphenol A, ethylene glycol in which ethylene oxide is added to both terminals of bisphenol A, and aluminum salts in which 1 to 3 moles of nitrosophenylhydroxylamine are added. These may be used alone or in combination of two or more. Among these, from the viewpoint of resistance to plating penetration, an aluminum salt having 3 moles of nitrosophenylhydroxylamine added thereto is preferred.

[0108] The amount of plasticizer in the photosensitive resin composition and the photosensitive resin layer is preferably 1% by mass to 50% by mass, and more preferably 1% by mass to 30% by mass, based on the total solid mass of the photosensitive resin composition and the photosensitive resin layer, respectively. When the amount of plasticizer is 1% by mass or more, delay in development time is suppressed and flexibility is imparted to the cured film, and when it is 50% by mass or less, insufficient curing and edge fuse tend to be suppressed.

[0109] <Solvent> As described below, the photosensitive resin layer can be formed by dissolving each component in a solvent, applying the solution to a support film, and then drying. The photosensitive resin composition according to the present disclosure may optionally contain a solvent in addition to the above-described components. The resulting photosensitive resin layer may also contain residual solvent. Examples of the solvent include ketones such as methyl ethyl ketone (MEK), and alcohols such as methanol, ethanol, and isopropanol.

[0110] <Film Thickness> The film thickness of the photosensitive resin layer is 80 μm or more, preferably more than 80 μm, more preferably 90 μm or more, even more preferably 100 μm or more, even more preferably 110 μm or more, and particularly preferably 115 μm or more. In plating methods, photosensitive resin laminates having a thick (80 μm or more) photosensitive resin layer may be used. In addition, a thick photosensitive resin layer can suppress the generation of laminar air, thereby obtaining a photosensitive resin laminate suitable for plating methods, such as forming metal pillars. The film thickness of the photosensitive resin layer may be 200 μm or more, 300 μm or more, or 400 μm or more. The upper limit of the film thickness of the photosensitive resin layer is not limited, but can be, for example, 1000 μm or less, 800 μm or less, or 500 μm or less.

[0111] <Optical Properties> The higher the transmittance of the photosensitive resin layer according to the present disclosure at a wavelength of 365 nm, the better the resolution of the resist pattern, and is therefore preferably 10% or more, even more preferably 20% or more, even more preferably 30% or more, and particularly preferably 50% or more. From the same viewpoint, the higher the transmittance of the photosensitive resin layer at a wavelength of 405 nm, the more preferably it is 50% or more, even more preferably 60% or more, even more preferably 70% or more, and particularly preferably 80% or more. From the same viewpoint, the ratio (A) / (T) of the absorbance (A) of the photosensitive resin layer at a wavelength of 365 nm to the film thickness (T) of the photosensitive resin layer is preferably 0.02 or less, more preferably 0.01 or less, even more preferably 0.005 or less, and most preferably 0.003 or less.

[0112] <Support Film> The support film is preferably transparent and transmits light emitted from the exposure light source. Examples of support films include polyethylene terephthalate films, polyvinyl alcohol films, polyvinyl chloride films, vinyl chloride copolymer films, polyvinylidene chloride films, vinylidene chloride copolymer films, polymethyl methacrylate copolymer films, polystyrene films, polyacrylonitrile films, styrene copolymer films, polyamide films, and cellulose derivative films. These films can also be stretched as needed. The haze of the support film is preferably 5% or less, more preferably 1% or less, even more preferably 0.5% or less, and most preferably 0.3% or less. A thinner support film is advantageous in terms of image formation and economy, but considering the function of maintaining strength, a haze of 10 μm or more is preferred. Furthermore, when the thickness of the photosensitive resin layer is 80 μm or more, i.e., when the photosensitive resin layer is a thick film, it is preferable that the support film is thick from the viewpoint of film thickness stability during coating, i.e., the thickness of the support film is preferably 20 μm or more, more preferably 50 μm or more, even more preferably 75 μm or more, and most preferably 100 μm or more. The thickness of the support film may be 500 μm or less from the viewpoint of slit processability.

[0113] The thickness of the support film may be 10% or more, or may be 20% or more, of the thickness of the photosensitive resin layer.

[0114] <Protective Layer> The photosensitive resin laminate may have a protective layer on the surface of the photosensitive resin layer opposite the support film. The protective layer serves to protect the photosensitive resin layer. The protective layer preferably has an appropriate adhesive strength to the photosensitive resin layer. That is, it is preferable that the adhesive strength of the protective layer to the photosensitive resin layer is sufficiently smaller than the adhesive strength of the support film to the photosensitive resin layer, so that the protective layer can be easily peeled from the photosensitive resin laminate. As the protective layer, for example, a polyethylene film, a polypropylene film, or a film with excellent peelability as disclosed in JP-A-59-202457 can be used. The thickness of the protective layer is preferably 10 μm to 100 μm, more preferably 10 to 50 μm.

[0115] <<Method for Producing Photosensitive Resin Laminate>> A photosensitive resin laminate can be produced by sequentially laminating a photosensitive resin layer and, if necessary, a protective layer on a support film. Known lamination methods can be used. For example, the components used in the photosensitive resin layer are mixed with a solvent that dissolves them to obtain a uniform solution (coating liquid). Examples of solvents include ketones such as methyl ethyl ketone (MEK), and alcohols such as methanol, ethanol, and isopropanol. The amount of solvent is preferably such that the viscosity of the coating liquid is 500 to 4,000 mPa·s at 25°C. The coating liquid is applied to a support film and then dried to form a photosensitive resin layer on the support film. Known methods can be used for coating, such as a method using a bar coater or a roll coater. Subsequently, if necessary, a protective layer is laminated on the photosensitive resin layer to produce a photosensitive resin laminate.

[0116] <<Method for Forming Resist Pattern, and Metal Pillar or Semiconductor Bump>> A resist pattern can be formed using the photosensitive resin laminate of the present disclosure. The method for forming a resist pattern can include: a step of laminating a photosensitive resin layer of the photosensitive resin laminate on a substrate (laminating step), a step of exposing the laminated photosensitive resin laminate (exposing step), a step of developing the exposed photosensitive resin laminate to form a resist pattern (developing step), and, if desired, a step of heating the obtained resist pattern (heating step).

[0117] A metal pillar or a semiconductor bump can be formed using a substrate on which a resist pattern has been formed. The method for forming a metal pillar or a semiconductor bump can include: an optional descumming and plating pretreatment step; a step of metal-plating or solder-plating the substrate on which the resist pattern has been formed to form a metal pillar or a semiconductor bump (plating step); an optional etching step of etching the substrate on which the resist pattern has been formed (etching step); and an optional stripping step of stripping the resist pattern from the substrate.

[0118] Hereinafter, a series of methods for forming a resist pattern and metal pillars or semiconductor bumps using a photosensitive resin laminate and a sputtered copper thin film as a substrate will be exemplified.

[0119] (1) Lamination process: For example, while peeling off the protective layer of the photosensitive resin laminate, the laminate is adhered to a substrate such as a sputtered copper thin film using, for example, a hot roll laminator. The sputtered copper thin film is preferably a copper-sputtered silicon wafer in which a copper layer is formed on a silicon wafer using a sputtering device.

[0120] (2) Exposure Step The exposure step can be, for example: a step of exposing the photosensitive resin layer of the photosensitive resin laminate laminated on the substrate through a mask film having a desired wiring pattern in a state where the mask film is in close contact with the photosensitive resin layer; a step of exposing the desired wiring pattern by a direct imaging exposure method; or a step of exposing by an exposure method in which an image of a photomask is projected through a lens.

[0121] (3) Development Step After the exposure step, the support film on the photosensitive resin layer is peeled off, and the unexposed area (in the case of a negative type) or the exposed area (in the case of a positive type) is developed and removed using an alkaline aqueous solution to form a resist pattern on the substrate. ２ CO ３ or K ２ CO ３ The alkaline aqueous solution is appropriately selected depending on the properties of the photosensitive resin layer, but it is preferable to use an aqueous solution of NaCl having a concentration of about 0.2 to 2% by mass and at a temperature of about 20 to 40°C. ２ CO ３ It is preferred to use an aqueous solution.

[0122] The conditions for the exposure and / or development steps may be determined depending on the desired shape of the metal pillar or semiconductor bump. For example, in the case of forming metal pillars such as metal cylinders or polygonal pillar patterns, the exposure and / or development steps may be performed to form a hole-shaped resist pattern having a relatively high ratio of circular hole diameter to film thickness exceeding 100 μm. In the case of a polygonal pillar pattern, the circular hole diameter may be regarded as the diameter of a circle inscribed in the polygon when the pattern is viewed from above.

[0123] (4) Heating Step: If desired, the formed resist pattern may be further heated, for example, at about 50°C to 300°C for 1 minute to 5 hours. By carrying out this heating step, it is possible to further improve the adhesion and chemical resistance of the resulting cured resist pattern. For heating in this case, for example, a hot plate, hot air, infrared, or far-infrared heating furnace can be used.

[0124] (5) Descum and Plating Pretreatment If desired, the substrate on which the resist pattern has been formed can be subjected to plasma treatment and / or water immersion treatment to carry out descum and plating pretreatment.

[0125] (6) Plating Step: The substrate surface exposed by development (e.g., the copper surface of a sputtered copper thin film) is plated with copper or solder to produce a conductive pattern. The plating solution is preferably a copper sulfate plating solution.

[0126] (7) Etching process: If desired, an etching solution may be sprayed onto the resist pattern formed through the above process to etch the copper surface not covered by the resist pattern, thereby forming a circuit pattern. Examples of the etching method include acid etching and alkaline etching, and the etching is carried out by a method suitable for the photosensitive resin laminate used.

[0127] (8) Stripping Step: The laminate is then treated with an aqueous solution having a stronger alkalinity than the developer, allowing the resist pattern to be stripped from the substrate. Examples of stripping solutions include aqueous solutions of alkaline components with a concentration of about 2 to 5% by mass and a temperature of about 40 to 70°C; aqueous solutions of NaOH or KOH; dimethyl sulfoxide (DMSO); tetramethylammonium hydroxide (TMAH); mixtures of DMSO and TMAH; SPR920 (product name); R-101 (product name); and stripping solutions that do not contain DMSO (hereinafter referred to as "DMSO-free stripping solutions"). Among these, DMSO-free stripping solutions are preferred from the viewpoint of the effects of the photosensitive resin laminate according to the present disclosure and from the viewpoint of reducing the environmental impact. The DMSO-free stripping solution may contain one or more of the above-mentioned components other than DMSO.

[0128] The photosensitive resin laminate, resist pattern, metal pillar, and semiconductor bump described above can be used, for example, to form a semiconductor package, a wafer level package (WLP), and the like.

[0129] Examples 1 to 43 and Comparative Example 1 Preparation of Photosensitive Resin Laminate The materials shown in Tables 1 and 2 were mixed in the composition shown in Table 3 (where the number for each component indicates the amount (parts by mass) of the solid content), and methyl ethyl ketone measured to give a solid content concentration of 60% was added. The mixture was thoroughly stirred and mixed to obtain a photosensitive resin coating solution. The obtained coating solution was uniformly applied using a bar coater to the surface of a 16 μm thick polyethylene terephthalate film (manufactured by Toray Industries, Inc., FB-40) used as a support film, and then dried in a dryer at 95°C for 12 minutes to form a photosensitive resin layer. The thickness (T) of the photosensitive resin layer after drying was 120 μm.

[0130] A 19 μm thick polyethylene film (GF-18, manufactured by Tamapoly Co., Ltd.) was laminated as a protective layer on the surface of the photosensitive resin layer where the support film was not laminated to obtain a photosensitive resin laminate.

[0131] [Measurement and Evaluation] <Photosensitive Layer Transmittance at 365 nm and 405 nm> After peeling off the protective film from the photosensitive laminate, the transmittance of the photosensitive layer at wavelengths of 365 nm and 405 nm was measured using a spectrophotometer U-3010 (manufactured by Hitachi High-Technologies Corporation) with a polyethylene terephthalate film (support film) as a reference. The measurement was performed with a slit set to 4 nm and a scan speed of 600 nm / min.

[0132] <Evaluation Substrate> <Substrate> As a substrate, a wafer (copper-sputtered silicon wafer) was prepared by forming a copper layer of 2000 angstroms (Å) thick on a 6-inch silicon wafer using a sputtering apparatus (L-440S-FHL) manufactured by Canon Anelva Corporation.

[0133] <Lamination> While peeling off the polyethylene film from the photosensitive resin laminate, the laminate was laminated onto a substrate preheated to 70° C. using an air damper type hot roll laminator (VA-400III, manufactured by Taisei Laminator Co., Ltd.) at a roll temperature of 70° C. The air pressure was set to 0.20 MPa and the lamination speed was set to 0.18 m / min.

[0134] <Exposure> A glass chrome mask was prepared in which a circular hole pattern (a pattern in which the outer circle is exposed and the inner circle is not exposed to the photosensitive material) was arranged in a square lattice so that the diameter:center distance between adjacent circular holes was 1:2 in 5 μm increments from 10 μm to 100 μm. Using this glass chrome mask, an Ultratech Prisma ghi stepper (manufactured by Ultratech) was used to apply 200 mJ / cm ２ The illuminance measured on the substrate surface was 2400 mW / cm ２ It was.

[0135] <Development> After the above <Exposure>, the PET film was peeled off from the substrate, and then a 1% by mass Na ２ CO ３ The aqueous solution was sprayed onto the photosensitive resin layer at a liquid temperature of 30°C and a flow rate of 200 mL / min (spray development). For each experimental example, the minimum development time under the above conditions was determined in advance, and twice the minimum development time was set as the development time. The "minimum development time" refers to the shortest time required for a wafer having a fully unexposed photosensitive resin layer laminated thereon to completely dissolve when developed under the above conditions. A smaller "minimum development time" indicates better performance. The evaluation criteria for the minimum development time under these evaluation conditions are as follows: 160 seconds or less: Pass; 140 seconds or less: Good; 120 seconds or less: Extremely good; 110 seconds or less: Best. After development, water was sprayed onto the photosensitive resin layer (water rinse spray). The conditions and time for the water rinse spray were set the same as for the developer spray.

[0136] <Descum treatment and plating pretreatment> After the above <development>, the substrate was subjected to a low-pressure plasma treatment using a low-pressure plasma device (EXAM, manufactured by Shinko Seiki Co., Ltd.) at 50 Pa, 133 W, and O ２ 40mL / min, CF ４ The resist pattern was subjected to plasma treatment (descum treatment and plating pretreatment) under conditions of 1 mL / min and 1500 seconds.

[0137] <Copper sulfate plating> 968 mL of SC-50 MU MA (manufactured by MICROFAB®), 20 mL of SC-50 R1 (manufactured by MICROFAB®), and 12 mL of SC-50 R2 (manufactured by MICROFAB®) were mixed to obtain a copper sulfate plating solution. Using the obtained copper sulfate plating solution, a substrate (6 cm × 12.5 cm) that had undergone the above-described <Descum treatment and plating pretreatment> was copper-plated using a Haring Cell Uniform Plating Apparatus (manufactured by Yamamoto Plating Tester Co., Ltd.). The current value was adjusted so that copper was deposited at a height (thickness) of 1 μm per minute. This resulted in a 100 μm copper plating film.

[0138] <Removal> The substrate after the above <Copper sulfate plating> was immersed in a stripper solution of SPR920 (manufactured by KANTO-PPC) at 68°C for a time twice the minimum peeled piece dissolution time. The minimum peeled piece dissolution time was calculated by measuring the time it took for the solid exposed portion of the resist pattern (the portion not having the circular pattern) to dissolve in the stripper solution after being peeled from the substrate at each temperature. A smaller value for the "minimum peeled piece dissolution time" indicates better performance. The evaluation criteria for the minimum peeled piece dissolution time under these evaluation conditions are as follows: 500 seconds or less: Pass; 350 seconds or less: Good; 300 seconds or less: Very good; 250 seconds or less: Best. The substrate immersed for the desired time was rinsed with water and air-dried. This resulted in the resist pattern being peeled off, yielding a substrate with a copper pillar pattern formed on it. The copper plating film remaining after the above <Removal> functions as copper pillars for wiring.

[0139] [Evaluation Method] <Resolution> The resist pattern formed after the above <Exposure> and <Development> was observed under an optical microscope at a magnification of 10x, and the resolution was evaluated based on the smallest mask size at which the space portions (unexposed portions) were removed without residue. The smaller this value, the better the resolution. The evaluation criteria for resolution under these evaluation conditions are as follows: 60 μm or less: Pass 50 μm or less: Good 40 μm or less: Extremely good 30 μm or less: Best

[0140] <Plating Formability> The copper pillar pattern formed after the above <copper sulfate plating> and <peeling>, each having a diameter of 60 μm and a center-to-center spacing of 120 μm between adjacent circular holes, was observed under an optical microscope at 5x magnification. 2,000 patterns were observed within an area of ​​1 cm x 3 mm, and the number of plating defects was counted as the number of areas where copper pillars were not formed or where unpeeled resist residue was present, and the plating formability was evaluated. A smaller number of plating defects indicates better plating formability. The evaluation criteria for the number of plating defects under these evaluation conditions are as follows: 5 or less: Pass; 1 or less: Good; 0: Best. In Comparative Example 1, the peeled pieces did not dissolve, and resist remained on the substrate after peeling, so plating formability could not be evaluated.

[0141] <Plating Penetration Resistance> The copper pillar pattern formed after the above-mentioned <copper sulfate plating> and <peeling>, each having a diameter of 60 μm and a center-to-center spacing between adjacent circular holes of 120 μm, was observed at the bottom of the copper pillar at a magnification of 3000 times using a scanning electron microscope (S-3400N, manufactured by Hitachi High-Technologies Corporation) to check for the presence or absence of plating penetration. Absence of plating penetration indicates good performance.

[0142] <Plating Formability When Using a DMSO-Free Stripper> After the same exposure, development, descum treatment, and plating pretreatment as above, and copper sulfate plating were performed, the substrate was immersed for 10 minutes in a stripper consisting of 2% by mass of tetramethylammonium hydroxide, 8% by mass of propylene glycol, and 90% by mass of N-methylpyrrolidone. The immersed substrate was rinsed with water and air-dried, and the copper pillar pattern formed, with a diameter of 60 μm and a center-to-center spacing of 120 μm between adjacent circular holes, was observed at 5x magnification using an optical microscope. An area of ​​1 cm x 3 mm was observed, and the number of plating defects was counted as the number of areas where copper pillars were not formed or where there was unstripped resist residue, to evaluate plating formability. The smaller the number of plating defects, the better the plating formability. The evaluation criteria for the number of plating defects under these evaluation conditions were as follows: 5 or less: Pass; 1 or less: Good; 0: Very good

[0143]

[0144]

[0145]

[0146]

[0147]

[0148]

[0149]

[0150]

[0151]

[0152]

Claims

1. A photosensitive resin laminate for forming a resist pattern to form metal pillars and semiconductor bumps, comprising a support film and a photosensitive resin layer containing a photosensitive resin composition, wherein the photosensitive resin composition contains, relative to the total solid content of the photosensitive resin composition: (A) 30% to 70% by mass of an alkali-soluble polymer; (B) 20% to 50% by mass of a compound having an ethylenically unsaturated bond; and (C) 0.01% to 20% by mass of a photopolymerization initiator; wherein the component (B) contains at least: (B-1) a compound having a cyclic group, an ethylene oxide chain, and two acryloyl groups in one molecule; and (B-2) a compound having three or more acryloyl groups; and wherein the photosensitive resin layer has a thickness of 80 μm or more.

2. The compound (B-1) is represented by the following general formula (II): {wherein each EO independently represents ethylene oxide, each A independently represents an acryloyl group, and each m and n independently represents an integer of 1 to 100}.

3. The photosensitive resin laminate for forming a resist pattern for forming metal pillars and semiconductor bumps according to claim 1 or 2, wherein the mass ratio (methacrylate monomer / acrylate monomer) of the compound having a methacryloyl group to the compound having an acryloyl group in component (B) is 0 or more and less than 0.

5.

4. The photosensitive resin laminate for forming a resist pattern for forming metal pillars and semiconductor bumps according to claim 3, wherein the mass ratio (methacrylate monomer / acrylate monomer) of the compound having a methacryloyl group to the compound having an acryloyl group in component (B) is less than 0.

1.

5. A photosensitive resin laminate for forming a resist pattern for forming metal pillars and semiconductor bumps according to claim 1 or 2, wherein the concentration of ethylenically unsaturated bonds in the photosensitive resin layer is 1.0 mmol / g or more.

6. The photosensitive resin laminate for forming a resist pattern for forming metal pillars and semiconductor bumps according to claim 1 or 2, wherein the mass ratio of the monomer modified with an alkylene oxide having 3 or more carbon atoms to the EO-modified monomer in component (B) ((monomer modified with an alkylene oxide having 3 or more carbon atoms) / EO-modified monomer) is 0 or more and less than 0.

1.

7. The photosensitive resin laminate for forming a resist pattern for forming metal pillars and semiconductor bumps according to claim 1 or 2, wherein the mass ratio of the propylene oxide or butylene oxide modified monomer to the ethylene oxide modified monomer in component (B) ((propylene oxide modified monomer + butylene oxide modified monomer) / ethylene oxide modified monomer) is 0 or more and less than 0.

1.

8. A photosensitive resin laminate for forming a resist pattern for forming metal pillars and semiconductor bumps according to claim 1 or 2, wherein the component (B) further contains a compound having a monofunctional ethylenic double bond.

9. A photosensitive resin laminate for forming a resist pattern for forming metal pillars and semiconductor bumps according to claim 1 or 2, wherein the component (A) includes a copolymer having a monomer having an aromatic ring as a copolymerization component.

10. A photosensitive resin laminate for forming a resist pattern for forming metal pillars and semiconductor bumps according to claim 1 or 2, wherein the component (A) includes a copolymer having benzyl (meth)acrylate as a copolymerization component.

11. A photosensitive resin laminate for forming a resist pattern to form metal pillars and semiconductor bumps, comprising a support film and a photosensitive resin layer containing a photosensitive resin composition, wherein the photosensitive resin composition contains, relative to the total solid content of the photosensitive resin composition: (A) 30% by mass to 70% by mass of an alkali-soluble polymer; (B) 20% by mass to 50% by mass of a compound having an ethylenically unsaturated bond; and (C) 0.01% by mass to 20% by mass of a photopolymerization initiator; and the component (B) contains at least: (B-1) a compound having a cyclic group, an ethylene oxide chain, and two acryloyl groups in one molecule; a photosensitive resin laminate for forming a resist pattern for forming a metal pillar and a semiconductor bump, wherein the mass ratio (methacrylate monomer / acrylate monomer) of the compound having a methacryloyl group to the compound having an acryloyl group in the component (B) is 0 or more and less than 0.5, and the thickness of the photosensitive resin layer is 80 μm or more.

12. The compound (B-1) is represented by the following general formula (II): {wherein each EO independently represents ethylene oxide, each A independently represents an acryloyl group, and m and n independently represent an integer of 1 to 100}.

13. A photosensitive resin laminate for forming a resist pattern for forming metal pillars and semiconductor bumps according to claim 11 or 12, wherein the mass ratio (methacrylate monomer / acrylate monomer) of the compound having a methacryloyl group to the compound having an acryloyl group in component (B) is less than 0.

1.

14. The photosensitive resin laminate for forming a resist pattern for forming metal pillars and semiconductor bumps according to claim 11 or 12, further comprising (B-2) a compound having three or more acryloyl groups as the component (B).

15. A photosensitive resin laminate for forming a resist pattern for forming metal pillars and semiconductor bumps according to claim 1 or 11, which is used in a process of stripping a resist pattern formed by exposing and developing the photosensitive resin laminate using a stripping solution that does not contain dimethyl sulfoxide.

Images