Photosensitive resin composition and pattern forming method

Abstract

The present invention is a photosensitive resin composition and a pattern forming method. A white photosensitive resin composition comprising (A) an acid-crosslinkable group-containing silicone resin, (B) a photoacid generator and (C) a white pigment has sufficient reflectivity, good reliability in terms of adhesion and crack resistance, resolution, flexibility and light resistance.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This nonprovisional application claims priority under 35 U.S.C. 119(a) to Patent Application No. 2018-134158 filed in Japan on July 17, 2018, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to a photosensitive resin composition and a pattern forming method. Background Art

[0004] In the prior art, photosensitive protective films for semiconductor devices and photosensitive insulating films for multilayer printed circuit boards are formed from photosensitive polyimide compositions, photosensitive epoxy resin compositions, photosensitive silicone compositions, etc. As a photosensitive material applied to protect such substrates and circuits, Patent Document 1 discloses a photosensitive silicone composition having flexibility. The photosensitive silicone composition can be cured at a low temperature and forms a coating that is completely reliable in terms of wet adhesion resistance and other properties, but is less resistant to chemicals such as photoresist strippers having high solubility, typically N-methyl-2-pyrrolidone (NMP).

[0005] In order to overcome the above problems, Patent Document 2 proposes a photosensitive silicone composition based on a silicone polymer containing a silicon phenylene structure. The composition is improved in chemical resistance to photoresist strippers and the like, but still has the problem that the cured coating peels off or cracks from the substrate in a thermal cycle test (a test of holding at -25°C for 10 minutes and at 125°C for 10 minutes is repeated for 1,000 cycles). Further improvement in reliability is required.

[0006] Many optical devices today require micromachining. For the purpose of micromachining, many resist compositions containing thermosetting acrylic resins and white pigments are used to form reflectors. These resist compositions have problems including poor resolution and lack of flexibility and adhesion in film form.

[0007] Reference List

[0008] Patent Document 1: JP-A 2002-088158 (USP 6,590,010, EP 1186624)

[0009] Patent Document 2: JP-A 2008-184571 (USP 7,785,766, EP 1953183)

[0010] Patent Document 3: JP-A 2002-283498 SUMMARY OF THE INVENTION

[0011] An object of the present invention is to provide a white photosensitive resin composition having sufficient reflectance, good reliability regarding adhesiveness and crack resistance, resolution, flexibility, and light resistance, and a pattern forming method using the composition.

[0012] The inventors have found that a photosensitive resin composition containing a silicone resin having an acid-crosslinkable group, a photoacid generator, and a white pigment is easy to form a film, the film is light-resistant and effective for microfabrication, and has good reliability regarding adhesiveness and crack resistance, resolution, and flexibility, while maintaining sufficient reflectance.

[0013] In one aspect, the present invention provides a photosensitive resin composition comprising (A) a silicone resin having an acid-crosslinkable group, (B) a photoacid generator, and (C) a white pigment.

[0014] Preferably, the acid-crosslinkable group is selected from an epoxy group, an oxetanyl group, and a vinyl ether group.

[0015] In a preferred embodiment, component (A) contains a silicone resin comprising repeating units having formulas (A1) to (A6).

[0016]

[0017] Wherein, R 1 to R 4 are each independently a monovalent hydrocarbon group of C 1 -C 20 which may contain a heteroatom, m is each independently an integer from 1 to 600, when m is an integer of at least 2, the groups R 3 may be the same or different and the groups R 4 may be the same or different, a, b, c, d, e, and f are numbers within the following ranges: 0 ≤ a ≤ 1, 0 ≤ b ≤ 1, 0 ≤ c ≤ 1, 0 ≤ d ≤ 1, 0 ≤ e ≤ 1, 0 ≤ f ≤ 1, 0 < c + d + e + f ≤ 1, and a + b + c + d + e + f = 1.

[0018] X 1 is a divalent group having formula (X1):

[0019]

[0020] Wherein, R 11 to R 14 are each independently a monovalent hydrocarbon group of C 1 -C 20 which may contain a heteroatom, p is an integer from 1 to 600, when p is an integer of at least 2, the groups R 13may be the same or different from the group R 14 Can be the same or different, R 15 and R 16 Each is independently hydrogen or methyl, and each x is independently an integer from 0 to 7.

[0021] X 2 is a divalent group having the formula (X2):

[0022]

[0023] Among them, Y 1 is a single bond, a methylene group, a propane-2,2-diyl group, a 1,1,1,3,3,3-hexafluoropropane-2,2-diyl group or a fluorene-9,9-diyl group, R 21 and R 22 Each independently is C 1 -C 4 Alkyl or alkoxy, when g is 2, the group R 21 can be the same or different. When h is 2, the group R 22 Can be the same or different, R 23 and R 24 Each is independently hydrogen or methyl, y is each independently an integer from 0 to 7, and g and h are each independently 0, 1 or 2.

[0024] X 3 is a divalent group having the formula (X3):

[0025]

[0026] Among them, R 31 and R 32 are each independently hydrogen or methyl, z is each independently an integer from 0 to 7, and R 33 C may contain ester or ether bonds 1 -C 8 A divalent hydrocarbon group.

[0027] Preferably, e and f are in the following ranges: 0 <e+f≤1。

[0028] Preferably, the white pigment (C) has an average particle size of at most 1 μm. More preferably, the white pigment (C) is titanium dioxide surface-treated with at least one compound selected from: hydrated oxides of Al, Si and Zr, polyols and organosilicon compounds. The photosensitive resin composition preferably contains 3 to 60% by weight of the white pigment (C).

[0029] The photosensitive resin composition may further contain (D) a crosslinking agent, (E) an antioxidant and / or (F) a solvent.

[0030] In another aspect, the present invention provides a pattern forming method comprising the steps of: (i) applying a photosensitive resin composition as defined herein onto a substrate to form a photosensitive resin coating thereon, (ii) exposing the photosensitive resin coating to radiation, and (iii) developing the exposed resin coating with a developer.

[0031] Beneficial effects of the present invention

[0032] A photosensitive resin composition comprising a specific silicone resin containing an acid-crosslinkable group, a photoacid generator and a white pigment is easy to form a film. The film is light-resistant and effective for micro-processing, and has good reliability, resolution and flexibility with respect to adhesion and crack resistance. The composition is therefore a useful material for forming a photosensitive resin film. DETAILED DESCRIPTION

[0033] As used herein, the notation (Cn-Cm) means groups containing n to m carbon atoms per group. "Optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not occur.

[0034] Photosensitive resin composition

[0035] One embodiment of the present invention is a photosensitive resin composition comprising (A) an acid-crosslinkable group-containing silicone resin, (B) a photoacid generator, and (C) a white pigment.

[0036] (A) Silicone resin

[0037] Component (A) is an organosilicon resin containing acid-crosslinkable groups, i.e., an organosilicon resin containing a siloxane structure and an acid-crosslinkable group. The term "acid-crosslinkable group" as used herein refers to a functional group that forms a chemical bond directly or via a crosslinking agent under the action of an acid. Preferably, the acid-crosslinkable group is an epoxy group, an oxetane group or a vinyl ether group, wherein an epoxy group is the most preferred.

[0038] The acid-crosslinkable group-containing silicone resin as component (A) is preferably an epoxy-containing silicone resin comprising repeating units of formulae (A1) to (A6). For simplicity, the repeating units of formulae (A1) to (A6) are sometimes referred to as repeating units (A1) to (A6), respectively.

[0039]

[0040] In formulas (A2), (A4) and (A6), R 1 To R 4 Each independently is C which may contain heteroatoms1 -C 20 monovalent hydrocarbon group, m is each independently an integer from 1 to 600. When m is an integer of at least 2, the group R 3 may be the same or different from the group R 4 In repeating units (A2), (A4) and (A6), when two or more siloxane units are included, all siloxane units may be the same or may include two or more different types of siloxane units. When two or more different types of siloxane units are included (i.e., m is an integer of at least 2), the siloxane units may be randomly or alternately bonded, or may include blocks each consisting of siloxane units of the same type.

[0041] The monovalent hydrocarbon group may be linear, branched or cyclic and includes, for example, monovalent aliphatic hydrocarbon groups such as C 1 -C 20 Alkyl and C 2 -C 20 Alkenyl and monovalent aromatic hydrocarbon groups, such as C 6 -C 20 Aryl and C 7 -C 20 Aralkyl.

[0042] Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclobutyl, n-pentyl, cyclopentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, norbornyl and adamantyl. Examples of alkenyl groups include ethenyl, propenyl, butenyl and pentenyl.

[0043] The monovalent aliphatic hydrocarbon group may contain heteroatoms. Specifically, some or all of the hydrogen atoms on the monovalent aliphatic hydrocarbon group may be replaced by halogen atoms such as fluorine, chlorine, bromine and iodine, or a carbonyl moiety, an ether bond or a thioether bond may be inserted between carbon atoms. A typical monovalent aliphatic hydrocarbon group with heteroatoms is 2-oxocyclohexyl.

[0044] Examples of the aryl group include phenyl, 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 2-ethylphenyl, 3-ethylphenyl, 4-ethylphenyl, 4-tert-butylphenyl, 4-butylphenyl, dimethylphenyl, naphthyl, biphenyl and terphenyl. Examples of the aralkyl group include benzyl and phenethyl.

[0045] The monovalent aromatic hydrocarbon group may contain heteroatoms. Specifically, some or all of the hydrogen atoms on the monovalent aromatic hydrocarbon group may be replaced by C 1 -C 10 Alkoxy, C 1 -C 10 Alkylthio, C 6 -C 20 Aryloxy or C6 -C 20 Arylthio substitution.

[0046] Suitable C 1 -C 10 The alkoxy group includes methoxy, ethoxy, n-propoxy, isopropoxy, cyclopropyloxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, cyclobutyloxy, n-pentyloxy, cyclopentyloxy, n-hexyloxy, cyclohexyloxy, n-heptyloxy, n-octyloxy, n-nonyloxy, n-decyloxy, norbornyloxy and adamantyloxy.

[0047] Suitable C 1 -C 10 The alkylthio group includes methylthio, ethylthio, n-propylthio, isopropylthio, cyclopropylthio, n-butylthio, isobutylthio, sec-butylthio, tert-butylthio, cyclobutylthio, n-pentylthio, cyclopentylthio, n-hexylthio, cyclohexylthio, n-heptylthio, n-octylthio, n-nonylthio, n-decylthio, norbornylthio and adamantylthio.

[0048] Suitable C 6 -C 20 The aryloxy group includes phenoxy, 2-methylphenoxy, 3-methylphenoxy, 4-methylphenoxy, 2-ethylphenoxy, 3-ethylphenoxy, 4-ethylphenoxy, 4-tert-butylphenoxy, 4-butylphenoxy, dimethylphenoxy, naphthoxy, biphenyloxy and terphenyloxy.

[0049] Suitable C 6 -C 20 The arylthio group includes a phenylthio group, a 2-methylphenylthio group, a 3-methylphenylthio group, a 4-methylphenylthio group, a 2-ethylphenylthio group, a 3-ethylphenylthio group, a 4-ethylphenylthio group, a 4-tert-butylphenylthio group, a 4-butylphenylthio group, a dimethylphenylthio group, a naphthylthio group, a biphenylthio group and a terphenylthio group.

[0050] Examples of aryl groups substituted with such groups include 2-methoxyphenyl, 3-methoxyphenyl, 4-methoxyphenyl, 2-ethoxyphenyl, 3-ethoxyphenyl, 4-ethoxyphenyl, 3-tert-butoxyphenyl, 4-tert-butoxyphenyl, biphenyloxyphenyl and biphenylthiophenyl.

[0051] The carbon number of the monovalent aliphatic hydrocarbon group is preferably 1 to 10, more preferably 1 to 8. The carbon number of the monovalent aromatic hydrocarbon group is preferably 6 to 14, more preferably 6 to 10.

[0052] Among these, R 1 To R 4 Preferred are methyl, ethyl, n-propyl or phenyl, with methyl and phenyl being more preferred.

[0053] In formulas (A2), (A4), and (A6), m is each independently an integer from 1 to 600, preferably an integer from 1 to 300, more preferably an integer from 1 to 100.

[0054] In formulas (A1) to (A6), a, b, c, d, e, and f are numbers within the following ranges: 0 ≤ a ≤ 1, 0 ≤ b ≤ 1, 0 ≤ c ≤ 1, 0 ≤ d ≤ 1, 0 ≤ e ≤ 1, 0 ≤ f ≤ 1, 0 < c + d + e + f ≤ 1, and a + b + c + d + e + f = 1; preferably 0.2 ≤ a + c + e ≤ 0.95, 0.05 ≤ b + d + f ≤ 0.8, 0 ≤ a + b ≤ 0.9, 0 ≤ c + d ≤ 0.7, 0 < e + f ≤ 1, and a + b + c + d + e + f = 1; more preferably 0.3 ≤ a + c + e ≤ 0.9, 0.1 ≤ b + d + f ≤ 0.7, 0 ≤ a + b ≤ 0.6, 0 ≤ c + d ≤ 0.4, 0.4 ≤ e + f ≤ 1, and a + b + c + d + e + f = 1.

[0055] In formulas (A1) and (A2), X 1 is a divalent group having formula (X1).

[0056]

[0057] In formula (X1), R 11 to R 14 are each independently a C 1 -C 20 monovalent hydrocarbon group which may contain a heteroatom, and p is an integer from 1 to 600. When p is an integer of at least 2, the groups R 13 may be the same or different and the groups R 14 may be the same or different. R 15 and R 16 are each independently hydrogen or methyl, and x is each independently an integer from 0 to 7. In the group having formula (X1), when two or more siloxane units are included, all the siloxane units may be the same or may include two or more different types of siloxane units. When two or more different types of siloxane units are included (i.e., p is an integer of at least 2), the siloxane units may be bonded randomly or alternately, or may include blocks each composed of the same type of siloxane units.

[0058] The optionally heteroatom-containing monovalent hydrocarbon group may be linear, branched, or cyclic, and examples thereof are as exemplified above for R 1 to R 4 . In particular, R 11 to R 14 are preferably methyl, ethyl, n-propyl, or phenyl, with methyl and phenyl being more preferred.

[0059] In formulas (A3) and (A4), X2 is a divalent group having the formula (X2).

[0060]

[0061] In formula (X2), Y 1 R is a single bond, methylene, propane-2,2-diyl, 1,1,1,3,3,3-hexafluoropropane-2,2-diyl or fluorene-9,9-diyl. 21 and R 22 Each independently is C 1 -C 4 Alkyl or alkoxy. When g is 2, the group R 21 can be the same or different. When h is 2, the group R 22 Can be the same or different. 23 and R 24 Each is independently hydrogen or methyl, y is each independently an integer from 0 to 7, and g and h are each independently 0, 1 or 2.

[0062] In formulas (A5) and (A6), X 3 is a divalent group having the formula (X3).

[0063]

[0064] In formula (X3), R 31 and R 32 are each independently hydrogen or methyl, and z is each independently an integer from 0 to 7.

[0065] In formula (X3), R 33 C may contain ester or ether bonds 1 -C 8 Divalent hydrocarbon group. The divalent hydrocarbon group may be linear, branched or cyclic, and examples thereof include alkane diyl groups such as methylene, ethylene, propane-1,2-diyl, propane-1,3-diyl, butane-1,2-diyl, butane-1,3-diyl and butane-1,4-diyl. An ester bond or an ether bond may be inserted between carbon atoms in the divalent hydrocarbon group. In particular, R 33 Preferred is methylene or ethylene, with methylene being more preferred.

[0066] The repeating units (A1) to (A6) may be bonded randomly or in blocks. The silicone resin containing acid-crosslinkable groups preferably has a silicone (siloxane unit) content of 30 to 80% by weight.

[0067] The silicone resin preferably has a weight average molecular weight (Mw) of 3,000 to 500,000, more preferably 5,000 to 200,000.It should be noted throughout this disclosure that Mw is measured by gel permeation chromatography (GPC) relative to polystyrene standards using tetrahydrofuran as the eluent.

[0068] The acid-crosslinkable group-containing silicone resin as component (A) can be prepared, for example, by mixing necessary amounts of a vinyl-containing compound and a hydrosilyl-containing compound corresponding to the portion of the silicone resin and conducting a hydrosilylation reaction in a conventional manner.

[0069] The acid-crosslinkable group-containing silicone resin as component (A) may be used alone or in combination of two or more.

[0070] (B) Photoacid Generator

[0071] The photoacid generator (PAG) as component (B) is typically a compound that decomposes to produce an acid when exposed, preferably when exposed to light with a wavelength of 190 to 500 nm. The acid produced serves as a curing catalyst. Typical PAGs include onium salts, diazomethane derivatives, oxadioxime derivatives, β-ketosulfone derivatives, disulfone derivatives, sulfonic acid nitrobenzyl ester derivatives, sulfonic acid ester derivatives, imidosulfonic acid ester derivatives, oximesulfonic acid ester derivatives, imidosulfonic acid ester derivatives and triazine derivatives.

[0072] Suitable onium salts include sulfonium salts having the formula (B1) and iodonium salts having the formula (B2).

[0073]

[0074] In formulas (B1) and (B2), R 101 To R 105 are each independently an optionally substituted C 1 -C 12 Alkyl, optionally substituted C 6 -C 12 Aryl or optionally substituted C 7 -C 12 Aralkyl. - It is a non-nucleophilic counter ion.

[0075] The alkyl group may be linear, branched or cyclic, and examples thereof include methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclobutyl, n-pentyl, cyclopentyl, cyclohexyl, norbornyl and adamantyl. Suitable aryl groups include phenyl, naphthyl and biphenyl. Suitable aralkyl groups include benzyl and phenethyl.

[0076] Suitable substituents include oxo, C1 -C 12 Straight chain, branched or cyclic alkoxy moiety, C 1 -C 12 Straight chain, branched chain or cyclic alkyl moiety, C 6 -C 24 Aryl moiety, C 7 -C 25 Aralkyl moiety, C 6 -C 24 Aryloxy moiety and C 6 -C 24 Arylthio moiety.

[0077] Preferably, R 101 To R 105 For optionally substituted alkyl such as methyl, ethyl, propyl, butyl, cyclohexyl, norbornyl, adamantyl and 2-oxocyclohexyl; optionally substituted aryl such as phenyl, naphthyl, biphenyl, o-, m- or p-methoxyphenyl, ethoxyphenyl, m- or p-tert-butoxyphenyl, 2-, 3- or 4-methylphenyl, ethylphenyl, 4-tert-butylphenyl, 4-butylphenyl, dimethylphenyl, terphenyl, biphenyloxyphenyl and biphenylthiophenyl; and optionally substituted aralkyl such as benzyl and phenethyl. Among these, optionally substituted aryl and optionally substituted aralkyl are more preferred.

[0078] Examples of non-nucleophilic counterions include halides such as chloride and bromide; fluoroalkanesulfonate ions such as trifluoromethanesulfonate, 1,1,1-trifluoroethanesulfonate, and nonafluorobutanesulfonate; arylsulfonate ions such as toluenesulfonate, benzenesulfonate, 4-fluorobenzenesulfonate, and 1,2,3,4,5-pentafluorobenzenesulfonate; alkanesulfonate ions such as methanesulfonate and butanesulfonate; fluoroalkanesulfonimide ions such as trifluoromethanesulfonimide; fluoroalkanesulfonylmethide ions such as tris(trifluoromethanesulfonyl)methane anion; and borate ions such as tetraphenylborate and tetrakis(pentafluorophenyl)borate.

[0079] Suitable diazomethane derivatives include compounds having formula (B3).

[0080]

[0081] In formula (B3), R 111 and R 112 Each independently is C 1 -C 12 Alkyl or haloalkyl, optionally substituted C 6 -C 12 Aryl or C 7 -C12 Aralkyl.

[0082] The alkyl group may be linear, branched or cyclic and may be, for example, as described above for R 101 To R 105 Suitable haloalkyl groups include trifluoromethyl, 1,1,1-trifluoroethyl, 1,1,1-trichloroethyl and nonafluorobutyl.

[0083] Examples of optionally substituted aryl groups include phenyl; alkoxyphenyl groups such as 2-, 3- or 4-methoxyphenyl, 2-, 3- or 4-ethoxyphenyl, 3- or 4-tert-butoxyphenyl; alkylphenyl groups such as 2-, 3- or 4-methylphenyl, ethylphenyl, 4-tert-butylphenyl, 4-butylphenyl and dimethylphenyl; and halogenated aryl groups such as fluorophenyl, chlorophenyl and 1,2,3,4,5-pentafluorophenyl. Suitable aralkyl groups include benzyl and phenethyl.

[0084] Suitable glyoxime derivatives include compounds having formula (B4).

[0085]

[0086] In formula (B4), R 121 To R 124 Each independently is C 1 -C 12 Alkyl or haloalkyl, optionally substituted C 6 -C 12 Aryl or C 7 -C 12 Aralkyl. 123 and R 124 may be bonded together with the carbon atoms to which they are attached to form a ring. In the case of a ring, R 123 and R 124 The combination of straight chain or branched C 1 -C 12 Alkylene.

[0087] Examples of alkyl, haloalkyl, optionally substituted aryl and aralkyl are as described above for R 111 To R 112 Suitable straight or branched chain alkylene groups include methylene, ethylene, propylene, butylene and hexylene.

[0088] Examples of the onium salt include diphenyliodonium trifluoromethanesulfonate, (p-tert-butoxyphenyl)phenyliodonium trifluoromethanesulfonate, diphenyliodonium p-toluenesulfonate, (p-tert-butoxyphenyl)phenyliodonium p-toluenesulfonate, triphenylsulfonium trifluoromethanesulfonate, (p-tert-butoxyphenyl)diphenylsulfonium trifluoromethanesulfonate, bis(p-tert-butoxyphenyl)phenylsulfonium trifluoromethanesulfonate, tri(p-tert-butoxyphenyl)sulfonium trifluoromethanesulfonate, triphenylsulfonium p-toluenesulfonate, (p-tert-butoxyphenyl)diphenylsulfonium p-toluenesulfonate, bis(p-tert-butoxyphenyl)phenylsulfonium p-toluenesulfonate, tri(p-tert-butoxyphenyl)sulfonium p-toluenesulfonate, triphenylsulfonium nonafluorobutanesulfonate, triphenylsulfonium butanesulfonate, trimethylsulfonium trifluoromethanesulfonate, trimethylsulfonium p-toluenesulfonate, cyclohexyl Methyl (2-oxocyclohexyl) sulfonium trifluoromethanesulfonate, cyclohexylmethyl (2-oxocyclohexyl) sulfonium p-toluenesulfonate, dimethylphenylsulfonium trifluoromethanesulfonate, dimethylphenylsulfonium p-toluenesulfonate, dicyclohexylphenylsulfonium trifluoromethanesulfonate, dicyclohexylphenylsulfonium p-toluenesulfonate, bis (4-tert-butylphenyl) iodonium hexafluorophosphate, diphenyl (4-thiophenoxyphenyl) sulfonium hexafluorophosphate fluoroantimonate, [4-(4-biphenylthio)phenyl]-4-biphenylphenylsulfonium tris(trifluoromethanesulfonyl)methide, triphenylsulfonium tetrakis(fluorophenyl)borate, tris[4-(4-acetylphenyl)thiophenyl]sulfonium tetrakis(fluorophenyl)borate, triphenylsulfonium tetrakis(pentafluorophenyl)borate, and tris[4-(4-acetylphenyl)thiophenyl]sulfonium tetrakis(pentafluorophenyl)borate.

[0089] Examples of diazomethane derivatives include bis(benzenesulfonyl)diazomethane, bis(p-toluenesulfonyl)diazomethane, bis(xylenesulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, bis(cyclopentylsulfonyl)diazomethane, bis(n-butylsulfonyl)diazomethane, bis(isobutylsulfonyl)diazomethane, bis(sec-butylsulfonyl)diazomethane, bis(n-propylsulfonyl)diazomethane, bis(isopropylsulfonyl)diazomethane, and bis(n-propylsulfonyl)diazomethane. diazomethane, bis(tert-butylsulfonyl)diazomethane, bis(n-pentylsulfonyl)diazomethane, bis(isopentylsulfonyl)diazomethane, bis(sec-pentylsulfonyl)diazomethane, bis(tert-pentylsulfonyl)diazomethane, 1-cyclohexylsulfonyl-1-(tert-butylsulfonyl)diazomethane, 1-cyclohexylsulfonyl-1-(tert-pentylsulfonyl)diazomethane and 1-tert-pentylsulfonyl-1-(tert-butylsulfonyl)diazomethane.

[0090] Examples of glyoxime derivatives include bis-O-(p-toluenesulfonyl)-α-dimethylglyoxime, bis-O-(p-toluenesulfonyl)-α-diphenylglyoxime, bis-O-(p-toluenesulfonyl)-α-dicyclohexylglyoxime, bis-O-(p-toluenesulfonyl)-2,3-pentanedioneglyoxime, bis-O-(p-toluenesulfonyl)-2-methyl-3,4-pentanedioneglyoxime, Diketone glyoxime, bis-O-(n-butanesulfonyl)-α-dimethylglyoxime, bis-O-(n-butanesulfonyl)-α-diphenylglyoxime, bis-O-(n-butanesulfonyl)-α-dicyclohexylglyoxime, bis-O-(n-butanesulfonyl)-2,3-pentanedione glyoxime, bis-O-(n-butanesulfonyl)-2-methyl-3,4-pentanedione glyoxime , bis-O-(methanesulfonyl)-α-dimethylglyoxime, bis-O-(trifluoromethanesulfonyl)-α-dimethylglyoxime, bis-O-(1,1,1-trifluoroethanesulfonyl)-α-dimethylglyoxime, bis-O-(tert-butanesulfonyl)-α-dimethylglyoxime, bis-O-(perfluorooctanesulfonyl)-α-dimethylglyoxime, bis-O-(cyclopentanesulfonyl)-α-dimethylglyoxime bis-O-(hexanesulfonyl)-α-dimethylglyoxime, bis-O-(benzenesulfonyl)-α-dimethylglyoxime, bis-O-(p-fluorobenzenesulfonyl)-α-dimethylglyoxime, bis-O-(p-tert-butylbenzenesulfonyl)-α-dimethylglyoxime, bis-O-(xylenesulfonyl)-α-dimethylglyoxime and bis-O-(camphorsulfonyl)-α-dimethylglyoxime.

[0091] Examples of the β-ketosulfone derivative include 2-cyclohexylcarbonyl-2-(p-toluenesulfonyl)propane and 2-isopropylcarbonyl-2-(p-toluenesulfonyl)propane.

[0092] Examples of the disulfone derivatives include diphenyl disulfone and dicyclohexyl disulfone.

[0093] Examples of the nitrobenzyl sulfonate derivative include 2,6-dinitrobenzyl p-toluenesulfonate and 2,4-dinitrobenzyl p-toluenesulfonate.

[0094] Examples of the sulfonic acid ester derivatives include 1,2,3-tris(methanesulfonyloxy)benzene, 1,2,3-tris(trifluoromethanesulfonyloxy)benzene, and 1,2,3-tris(p-toluenesulfonyloxy)benzene.

[0095] Examples of the iminosulfonate derivatives include phthalimido trifluoromethanesulfonate, phthalimido toluenesulfonate, 5-norbornene-2,3-dicarboxylic acid imino trifluoromethanesulfonate, 5-norbornene-2,3-dicarboxylic acid imino toluenesulfonate, 5-norbornene-2,3-dicarboxylic acid imino n-butylsulfonate and N-trifluoromethylsulfonyloxynaphthyl imide.

[0096] A typical oxime sulfonate derivative is α-(phenylsulfonyloxyimino)-4-methylphenylacetonitrile.

[0097] Examples of the imidosulfonate derivatives include (5-(4-methylphenyl)sulfonyloxyimino-5H-thiophen-2-ylidene)-(2-methylphenyl)acetonitrile and (5-(4-(4-methylphenylsulfonyloxy)phenylsulfonyloxyimino)-5H-thiophen-2-ylidene)-(2-methylphenyl)acetonitrile.

[0098] Also useful is 2-methyl-2-[(4-methylphenyl)sulfonyl]-1-[(4-methylthio)phenyl]-1-propane.

[0099] Preferred PAGs as component (B) are onium salts, with sulfonium salts being more preferred.

[0100] PAG (B) is preferably used in an amount of 0.05 to 20 parts by weight, and more preferably 0.2 to 5 parts by weight per 100 parts by weight of component (A). The amount of PAG within the range keeps the composition fully photocurable and avoids the risk of adversely affecting the curing of thick films due to light absorption of the PAG itself. In order to obtain the characteristics, transparency and light resistance of the present invention, it is recommended to reduce the amount of light-absorbing PAG added, as long as it does not hinder the photocuring behavior. PAG can be used alone or in combination of two or more.

[0101] (C) White pigment

[0102] Component (C) is a white pigment, the addition of which not only increases the whiteness of the cured product but also increases the resolution of the pattern forming material and improves the breakage properties (or prevents cracking) of the cured product or resist film, forming a non-peelable film.

[0103] Examples of white pigments include titanium dioxide, rare earth oxides such as yttrium oxide, zinc sulfate, zinc oxide and magnesium oxide. The shape of the white pigment is not particularly limited, and any known white pigment can be used. From the perspective of forming a fine pattern or micro-processing, the white pigment preferably has an average particle size of at most 1 μm, more preferably at most 0.5 μm. As a lower limit, the white pigment preferably has an average particle size of at least 10 nm. The average particle size used herein is a volume average particle size measured by a dynamic light scattering method.

[0104] From the viewpoint of whiteness, the preferred white pigment is titanium dioxide. Although titanium dioxide products prepared by both the sulfate process and the chloride process are acceptable, the chloride process product is preferred from the viewpoint of whiteness.

[0105] For the purpose of preventing the titanium oxide particles from agglomerating, titanium dioxide that has been subjected to a surface treatment is preferred. More preferably, the titanium dioxide is surface treated with any of hydrated oxides of Al, Si and Zr, polyols and organosilicon compounds, thereby inhibiting the photocatalytic activity of the titanium dioxide and making the titanium dioxide particles more compatible with or dispersible in the resin and inorganic filler.

[0106] Suitable organosilicon compounds for surface treatment include silane coupling agents, for example, polysiloxanes such as polydimethylsiloxane, polymethylphenylsiloxane, polymethylhydrogensiloxane and copolymers thereof; cyclosiloxanes such as hexamethylcyclotrisiloxane, heptamethylcyclotetrasiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane; chlorosilanes such as trimethylchlorosilane, dimethyldichlorosilane and methyltrichlorosilane; silanes having epoxy functionality such as 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane; silanes having methacrylic or acrylic groups such as 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane; silane, 3-acryloxypropyltriethoxysilane, methacryloxymethyltrimethoxysilane, methacryloxymethyltriethoxysilane, acryloxymethyltrimethoxysilane and acryloxymethyltriethoxysilane; silanes having a vinyl group, such as vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri(β-methoxyethoxy)silane and vinyltriacetoxysilane; mercaptosilanes, such as γ-mercaptopropyltrimethoxysilane and γ-mercaptopropylmethyldimethoxysilane; silanes having an alkyl group, such as methyltrimethoxysilane, methyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltrimethoxysilane and octyltriethoxysilane; other silanes, such as γ-chloropropyltrimethoxysilane and γ-anilinopropyltrimethoxysilane; and partial hydrolyzates of one or more of the foregoing silanes. Also useful are hexamethyldisiloxane and hexamethyldisilazane. Of these, polysiloxanes are preferred, with polydimethylsiloxane being more preferred.

[0107] The method for surface treatment of white pigment is not particularly limited. For example, surface treatment with organosilicon compound can be carried out by dry method of mixing pigment and organosilicon compound. Surface treatment with aluminum oxide or silicon dioxide can be carried out by wet method of immersing pigment in aqueous solution of sodium aluminate or sodium silicate and neutralizing with sulfuric acid to form surface layer on pigment.

[0108] White pigment (C) is preferably mixed in an amount of 3 to 60% by weight, more preferably 5 to 50% by weight, based on the composition. An amount of at least 3% by weight avoids any loss of whiteness, while an amount of up to 60% by weight avoids the risk of the composition being too fluid and insufficient for molding, causing insufficient loading or voids. White pigments can be used alone or in mixtures of two or more.

[0109] (D) Cross-linking agent

[0110] The photosensitive resin composition may further include (D) a crosslinking agent. The crosslinking agent reacts with the epoxy group on the component (C) and serves to promote pattern formation and increase the strength of the photocured resin film.

[0111] Preferably, the crosslinking agent is selected from compounds having an average of at least two epoxy groups, alicyclic epoxy groups or oxetane groups in the molecule. Among these compounds, low molecular weight compounds and high molecular weight compounds having a weight average molecular weight (Mw) of 100 to 20,000, especially 200 to 10,000 are preferred. Compounds having an Mw of at least 100 parts by weight can make the composition completely photocurable, while compounds having an Mw of up to 20,000 can adversely affect the heat resistance of the photocurable composition.

[0112] The crosslinking agent (D) may be mixed in an amount of 0 to 100 parts by weight per 100 parts by weight of component (A) and preferably 0.5 to 100 parts by weight, more preferably 1 to 50 parts by weight when used. At least 0.5 parts by weight of component (D) ensures sufficient curing upon exposure. As long as the amount of component (D) is at most 100 parts by weight, the proportion of component (C) in the resin composition is not reduced, allowing the cured composition to fully exert its effect. The crosslinking agent may be used alone or in combination.

[0113] (E) Antioxidants

[0114] The photosensitive resin composition may further contain (E) an antioxidant as an additive, which is effective for improving heat resistance. The antioxidant is typically selected from hindered phenol compounds and hindered amine compounds.

[0115] Although the hindered phenol compound used herein is not particularly limited, the hindered phenol compounds listed below are preferred.

[0116] 1,3,5-Trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene (trade name: IRGANOX1330), 2,6-di-tert-butyl-4-methylphenol (trade name: Sumilizer BHT), 2,5-di-tert-butylhydroquinone (trade name: Nocrac NS-7), 2,6-di-tert-butyl-4-ethylphenol (trade name: Nocrac M-17), 2,5-di-tert-amylhydroquinone (trade name: Nocrac DAH), 2,2'-methylenebis(4-methyl-6-tert-butylphenol) (trade name: Nocrac NS-6), 3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid diethyl ester (trade name: IRGANOX 1222), 4,4'-thiobis(3-methyl-6-tert-butylphenol) (trade name: Nocrac 300), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol) (trade name: NocracNS-5), 4,4'-butylenebis(3-methyl-6-tert-butylphenol) (trade name: Adeka Stab AO-40), 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate (trade name: Sumilizer GM), 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate (trade name: Sumilizer GS), 2,2'-methylenebis[4-methyl-6-(α-methylcyclohexyl)phenol], 4,4'-methylenebis(2,6-di-tert-butylphenol) (trade name: Seenox 226M), 4,6-bis(octylthiomethyl)-o-cresol (trade name: IRGANOX 1520L), 2,2'-ethylenebis(4,6-di-tert-butylphenol), octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (trade name: IRGANOX1076), 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane (trade name: Adeka Stab AO-30), tetrakis[methylene-(3,5-di-tert-butyl-4-hydroxyhydrocinnamate)]methane (trade name: Adeka Stab AO-60), triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate] (trade name: IRGANOX 245), 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylanilino)-1,3,5-triazine (trade name: IRGANOX 565), N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxyhydrocinnamic acid amide) (trade name: IRGANOX 1098), 1,6-hexanediol-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (trade name: IRGANOX 259), 2,2-thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (trade name: IRGANOX 1035), 3,9-bis[2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy]-1,1-dimethylethyl] 2,4,8,10-tetraoxaspiro[5.5]undecane (trade name: Sumilizer GA-80), tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate (trade name: IRGANOX3114), bis(ethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate) calcium / polyethylene wax 50 / 50 mixture (trade name: IRGANOX 1425WL), 2-ethylhexyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (trade name: IRGANOX 1135), 4,4'-thiobis(6-tert-butyl-3-methylphenol) (trade name: Sumilizer WX-R), 6-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-tert-butyldibenzo[d,f][1,3,2]dioxaphosphapin (trade name: Sumilizer GP), etc.

[0117] Although the hindered amine compound used herein is not particularly limited, the hindered amine compounds listed below are preferred.

[0118] p,p'-dioctyldiphenylamine (trade name: IRGANOX 5057), phenyl-α-naphthylamine (trade name: NocracPA), poly (2,2,4-trimethyl-1,2-dihydroquinoline) (trade name: Nocrac 224, 224-S), 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline (trade name: Nocrac AW), N,N'-diphenyl-p-phenylenediamine (trade name: NocracDP), N,N'-di-β-naphthyl-p-phenylenediamine (trade name: Nocrac White), N-phenyl-N'-isopropyl-p-phenylenediamine (trade name: Nocrac 810NA), N,N'-diallyl-p-phenylenediamine (trade name: Nonflex TP), 4,4'-(α,α-dimethylbenzyl)diphenylamine (trade name: Nocrac CD), p,p-toluenesulfonylaminodiphenylamine (trade name: Nocrac TD), N-phenyl-N'-(3-methacryloyloxy-2-hydroxypropyl)-p-phenylenediamine (trade name: Nocrac G1), N-(1-methylheptyl)-N'-phenyl-p-phenylenediamine (trade name: Ozonon 35), N,N'-di-sec-butyl-p-phenylenediamine (trade name: Sumilizer BPA), N-phenyl-N'-1,3-dimethylbutyl-p-phenylenediamine (trade name: Antigene 6C), alkylated diphenylamine (trade name: Sumilizer 9A), 1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidinyl succinic acid dimethyl ester condensation product (trade name: Tinuvin 622LD), poly[[6-(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidinyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidinyl)imino]] (trade name: CHIMASSORB 944), N,N'-bis(3-aminopropyl)ethylenediamine-2,4-bis[N-butyl-N-(1,2,2,6,6-pentamethyl-4-piperidinyl)amino]-6-chloro-1,3,5-triazine condensate (trade name: CHIMASSORB 119FL), bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate (trade name: Tinuvin 123), bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate (trade name: Tinuvin770), bis(1,2,2,6,6-pentamethyl-4-piperidinyl) 2-(3,5-di-tert-butyl-4-hydroxybenzyl)-2-n-butylmalonate (trade name: Tinuvin 144), bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate (trade name: Tinuvin 765), tetrakis(1,2,2,6,6-pentamethyl-4-piperidinyl) 1,2,3,4-butanetetracarboxylate (trade name: LA-57), tetrakis(2,2,6,6-tetramethyl-4-piperidinyl) 1,2,3,4-butanetetracarboxylate (trade name: LA-52), a mixture of 1,2,3,4-butanetetracarboxylic acid esterified with 1,2,2,6,6-pentamethyl-4-piperidinol and 1-tridecanol (trade name: LA-62), a mixture of 1,2,3,4-butanetetracarboxylic acid esterified with 2,2,6,6-tetramethyl-4-piperidinol and 1-tridecanol (trade name: L A-67), a mixture of 1,2,3,4-butanetetracarboxylic acid, 1,2,2,6,6-pentamethyl-4-piperidinol and 3,9-bis(2-hydroxy-1,1-dimethylethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane esterified with 1,2,3,4-butanetetracarboxylic acid, 2,2,6,6-tetra ... Stab LA-82), (1,2,2,6,6-pentamethyl-4-piperidinyl)-2-propylene carboxylate (trade name: Adeka Stab LA-87), etc.

[0119] The amount of component (E) used is not particularly limited as long as the benefits of the present invention are not impaired. When used, the amount of component (E) is preferably 0.01 to 1% by weight of the resin composition. Antioxidants may be used alone or in combination.

[0120] (F) Solvent

[0121] (F) A solvent may be added to the photosensitive resin composition in order to facilitate coating operation. The solvent (F) used herein is not particularly limited as long as the components (A) to (E) and other additives are soluble or dispersible therein.

[0122] Preferred solvents are organic solvents. Illustrative, non-limiting examples of organic solvents include ketones such as cyclohexanone, cyclopentanone and methyl-2-n-amyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol and 1-ethoxy-2-propanol; ethers such as propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether and diethylene glycol dimethyl ether; and esters such as propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, 3-methoxypropionic acid methyl ester, 3-ethoxypropionic acid ethyl ester, tert-butyl acetate, tert-butyl propionate and propylene glycol mono-tert-butyl ether acetate and gamma-butyrolactone. These solvents can be used alone or in combination of two or more.

[0123] Among these solvents, ethyl lactate, cyclohexanone, cyclopentanone, PGMEA, γ-butyrolactone and mixtures thereof are preferred, in which PAG is most soluble.

[0124] From the viewpoint of viscosity and compatibility of the resin composition, the solvent (F) is preferably added in an amount of 50 to 2,000 parts by weight, more preferably 50 to 1,000 parts by weight, and particularly 50 to 100 parts by weight per 100 parts by weight of components (A) and (C) combined.

[0125] Other additives

[0126] In addition to the aforementioned components, the photosensitive resin composition may contain other additives such as a surfactant, a silane coupling agent and a filler which are generally used to improve coating properties.

[0127] Preferred surfactants are nonionic surfactants, such as fluorochemical surfactants, such as perfluoroalkyl polyoxyethylene ethanol, fluorinated alkyl esters, perfluoroalkyl amine oxides and fluorinated organosiloxane compounds. These surfactants are commercially available. Illustrative examples include 3M's FC-430, from AGC SeimiChemical Co., Ltd. S-141 and S-145 from Daikin Industries Ltd. DS-401, DS-4031 and DS-451 from DIC Corp. F-8151, and X-70-093 from Shin-Etsu Chemical Co., Ltd. Preferred surfactants are Fluorad FC-430 and X-70-093. The amount of the surfactant is not particularly limited as long as the benefits of the present invention are not affected. When used, the amount of the surfactant is preferably 0.01 to 1 weight % of the resin composition.

[0128] The introduction of a silane coupling agent is effective for enhancing the adhesion of the resin composition to an adherend. Suitable silane coupling agents include epoxy silane coupling agents and aromatic amino silane coupling agents. The silane coupling agent can be used alone or in a mixed form. The amount of the silane coupling agent used is not particularly limited as long as the benefits of the present invention are not affected. When used, the amount of the silane coupling agent is preferably 0.01 to 5 weight % of the resin composition.

[0129] Fillers may also be mixed into the resin composition as other additives. The filler is typically silica or silicone powder having an average particle size of 0.01 to 20 μm. The amount of the filler is preferably up to 90% by weight of the resin composition, although not limited thereto.

[0130] Patterning method

[0131] Another embodiment of the present invention is a method for forming a pattern using the photosensitive resin composition defined above, the method comprising the steps of:

[0132] (i) applying the photosensitive resin composition onto a substrate to form a photosensitive resin coating thereon,

[0133] (ii) exposing the photosensitive resin coating to radiation to define exposed areas and unexposed areas, and

[0134] (iii) The exposed resin coating is developed with a developer to dissolve away unexposed areas of the resin coating and form a pattern of the resin coating.

[0135] First, in step (i), a photosensitive resin composition is applied to a substrate to form a photosensitive resin coating thereon. Examples of the substrate include silicon wafers, glass wafers, quartz wafers, plastic circuit boards, and ceramic circuit boards.

[0136] The coating technique may be any known technique, such as dip coating, spin coating, roller coating, etc. The coating weight may be appropriately selected for a particular purpose, preferably so as to form a photosensitive resin coating having a thickness of 0.1 to 200 μm, more preferably 1 to 150 μm.

[0137] The pre-wetting technique of distributing the solvent dropwise on the substrate before applying the resin composition can be used for the purpose of making the coating thickness on the substrate more uniform. The type and amount of the solvent distributed dropwise can be selected for a specific purpose. For example, preferred alcohols such as isopropyl alcohol (IPA), ketones such as cyclohexanone, and glycols such as propylene glycol monomethyl ether. The solvent used in the photosensitive resin composition can also be used.

[0138] At this time, if necessary, for efficient photocuring reaction, the coating material may be pre-baked to volatilize the solvent, etc. The pre-baking may be performed, for example, at 40 to 140° C. for 1 minute to about 1 hour.

[0139] Next in step (ii), the photosensitive resin coating is exposed to radiation to define exposed areas and unexposed areas. The exposure radiation preferably has a wavelength of 10 to 600nm, more preferably 190 to 500nm. Examples of radiation within the wavelength range include radiation of various wavelengths from a unit emitting radiation, particularly UV radiation, such as g-line, h-line or i-line and deep UV (248nm, 193nm). Among these, radiation of a wavelength of 248 to 436nm is preferred. A suitable exposure dose is 10 to 10,000mJ / cm 2 .

[0140] Exposure can be accomplished through a photomask. The photomask can be, for example, one that is perforated with a desired pattern. Although the material of the photomask is not particularly limited, it is preferably a material that can shield radiation within the above-mentioned wavelength range, typically chromium.

[0141] The next step may be post-exposure baking (PEB), which is effective for enhancing the developing sensitivity. PEB is preferably performed at 40 to 150° C. for 0.5 to 10 minutes. The exposed area of ​​the resin coating is cross-linked during the PEB process to form an insoluble pattern that is insoluble in an organic solvent as a developer.

[0142] Exposure or PEB is followed by a step (iii) of developing the exposed resin coating with a developer to dissolve away the unexposed areas of the resin coating and form a pattern of the resin coating. Preferred developers are organic solvents, including alcohols such as IPA, ketones such as cyclohexanone, and glycols such as propylene glycol monomethyl ether. Solvents used in photosensitive resin compositions are also useful. Development is carried out in a conventional manner, for example, by immersing the exposed coating in a developer. If necessary, development is followed by washing, rinsing and drying. In this way, a resin coating having a desired pattern is obtained.

[0143] In step (iv), the patterned coating can be post-cured in an oven or hot plate at a temperature of preferably 100 to 250° C., more preferably 150 to 220° C. The photosensitive resin composition ensures that a resin coating with improved film properties is obtained from post-curing even at a relatively low temperature of about 200° C. Post-curing is effective for increasing the cross-linking density of the resin coating and removing any residual volatile substances. The resulting coating has increased adhesion to the substrate, heat resistance, mechanical strength, good electrical properties and bonding strength. Post-curing temperatures within the range of 100 to 250° C. are preferred for obtaining the above-mentioned properties. Post-curing time is preferably 10 minutes to 10 hours, more preferably 10 minutes to 3 hours. The post-cured resin coating has a thickness of 1 to 200 μm, preferably 5 to 50 μm. Through the aforementioned steps, a cured film suitable for final reflector application is obtained.

[0144] Photosensitive dry film

[0145] Another embodiment of the present invention is a photosensitive dry film including a support and a photosensitive resin coating of a photosensitive resin composition thereon.

[0146] The photosensitive dry film (support + photosensitive resin coating) is solid, and the photosensitive resin coating does not contain a solvent. This eliminates the risk of bubbles generated by the volatilization of the solvent being left inside the resin coating and between the resin coating and the uneven substrate surface. The photosensitive resin coating preferably has a thickness of 1 to 200 μm, more preferably 3 to 100 μm.

[0147] In addition, the viscosity and fluidity of the photosensitive resin coating are closely related. As long as the photosensitive resin coating has a viscosity in an appropriate range, it shows sufficient fluidity to fill deeply even in a narrow gap, or it softens to enhance adhesion to the substrate. Therefore, from the viewpoint of fluidity, the photosensitive resin coating should have a viscosity in the range of 10 to 5,000 Pa·s, more preferably 30 to 2,000 Pa·s, and even more preferably 50 to 300 Pa·s at a temperature of 80 to 120°C. It should be noted that the viscosity is measured by a rotational viscometer.

[0148] The photosensitive dry film has the advantage that when closely attached to a substrate having irregularities on its surface, a photosensitive resin coating is applied, thereby following the irregularities and achieving high flatness. Since the photosensitive resin composition is characterized by softening properties, high flatness can be actively achieved. In addition, if the photosensitive resin coating is in close contact with the substrate in a vacuum environment, the generation of a gap therebetween is effectively suppressed.

[0149] The photosensitive dry film can be manufactured by applying the photosensitive resin composition to a support and drying the resin composition to a resin coating. The equipment for manufacturing the photosensitive dry film can be a coating machine commonly used to manufacture pressure-sensitive adhesive products. Suitable coating machines include, for example, a notch wheel coater, a notch wheel reverse coater, a multi-purpose coater (multiplecoater), a die coater, a lip plate coater, a lip plate reverse coater, a gravure coater, an offset gravure coater, a three roll bottom reverse coater (three roll bottom reverse coater) and a four roll bottom reverse coater (four rollbottom reverse coater).

[0150] The support (film) is unwound from a feed roll in a coating machine, conveyed through the head of the coating machine, where a photosensitive resin composition is applied to the support to a predetermined cumulative amount, and then moved through a hot air circulation oven at a predetermined temperature for a predetermined time, where the photosensitive resin coating is dried on the support. The support having the photosensitive resin coating thereon and the protective film unwound from another feed roll in the coating machine are then conveyed through a laminating roller under a predetermined pressure, thereby bonding the protective film to the photosensitive resin coating on the support, whereupon the laminate (photosensitive dry film with protective film) is wound on a pick-up shaft in the coating machine. Preferably, the oven temperature is 25 to 150° C., the conveying time is 1 to 100 minutes, and the bonding pressure is 0.01 to 5 MPa.

[0151] The support film used in the photosensitive dry film can be a single film or a multilayer film composed of multiple stacked polymer layers. Examples of film materials include synthetic resins such as polyethylene, polypropylene, polycarbonate and polyethylene terephthalate (PET), wherein PET films are preferred due to their suitable flexibility, mechanical strength and heat resistance. These films may have been pretreated, such as by corona treatment or coating with a release agent. Such films are commercially available, for example, from Toray Advanced Film Co., Ltd. WZ(RX) and BX8(R); E7302 and E7304 from Toyobo Co., Ltd.; G31 and G71T1; and PET38×1-A3, PET38×1-V8 and PET38×1-X08 from Nippa Co., Ltd.

[0152] The protective film used in the photosensitive dry film can be similar to the support film. PET and polyethylene films with appropriate flexibility are particularly preferred. Such films are also commercially available. For example, PET films are as mentioned above, and polyethylene films include GF-8 from Tamapoly Co., Ltd. and O-type PE films from Nippa Co., Ltd.

[0153] Both the support and the protective film preferably have a thickness of 10 to 100 μm, more preferably 25 to 50 μm, in order to stably produce a photosensitive dry film and prevent winding and curling on a pickup roller.

[0154] Pattern forming method using photosensitive dry film

[0155] Another embodiment of the present invention is a pattern forming method comprising the following steps:

[0156] (i') using a photosensitive dry film to form a photosensitive resin coating on a substrate,

[0157] (ii) exposing the photosensitive resin coating to radiation to define exposed areas and unexposed areas,

[0158] (iii) The exposed resin coating is developed with a developer to dissolve away unexposed areas of the resin coating and form a pattern of the resin coating.

[0159] In step (i'), the photosensitive dry film is used to form a photosensitive resin coating on the substrate. Specifically, the photosensitive dry film is bonded to the substrate at its photosensitive resin coating to form a photosensitive resin coating on the substrate. When the photosensitive dry film is covered with a protective film, the dry film is bonded to the substrate at its photosensitive resin coating after the protective film is peeled off therefrom to form a photosensitive resin coating on the substrate. The dry film can be bonded using a film bonding device.

[0160] The film laminating device is preferably a vacuum laminator. The photosensitive dry film is installed in the film laminating device, where the protective film is peeled off from the dry film. In a vacuum chamber maintained at a predetermined vacuum degree, on a workbench at a predetermined temperature, the exposed photosensitive resin coating of the dry film is tightly bonded to the substrate using a bonding roller under a predetermined pressure. Preferably, the temperature is 60 to 120°C, the pressure is 0 to 5.0MPa, and the vacuum degree is 50 to 500Pa.

[0161] If necessary, the assembly of the photosensitive resin coating on the substrate may be prebaked to promote the photocuring reaction of the photosensitive resin coating or enhance the adhesion between the resin coating and the substrate. The prebaking may be performed, for example, at 40 to 140° C. for 1 minute to 1 hour.

[0162] As with the pattern forming method using the photosensitive resin composition, the photosensitive resin coating layer attached to the substrate can be subjected to the following steps: (ii) exposing the photosensitive resin coating layer to radiation, (iii) developing the exposed resin coating layer with a developer to dissolve away the unexposed areas of the resin coating layer and form a pattern of the resin coating layer, and optionally (iv) post-curing the patterned coating layer. It is to be noted that the support of the photosensitive dry film can be removed by mechanical stripping or the like before pre-baking or before PEB, depending on the specific method.

[0163] The pattern forming method using the photosensitive resin composition or the photosensitive dry film facilitates the formation of a fine-size pattern of a thick film.

[0164] Films formed from the photosensitive resin composition are best suited as reflectors in optoelectronic semiconductor devices having LEDs mounted thereon.

[0165] Example

[0166] Examples of the present invention are given below by way of illustration and not by way of limitation. It is noted that the weight average molecular weight (Mw) is measured by gel permeation chromatography (GPC) relative to monodisperse polystyrene standards using a GPC column TSKgel SuperHZM-H (Tosoh Corp.) under the following analytical conditions: flow rate 0.6 mL / min, tetrahydrofuran eluent and column temperature 40° C. All parts are by weight (pbw).

[0167] Compounds (S-1) to (S-5) used in Examples are shown below.

[0168]

[0169] Notably, compound (S-2) can be obtained from Shin-Etsu Chemical Co., Ltd.

[0170] [1] Synthesis of silicone resins containing acid-crosslinkable groups

[0171] Synthesis Example 1

[0172] Synthesis of Resin A-1

[0173] A 3L flask equipped with a stirrer, a thermometer, a nitrogen purge line and a reflux condenser was charged with 265.0 g (1.00 mol) of compound (S-5), and then charged with 2,000 g of toluene and heated at 70° C. Thereafter, 1.0 g of a chloroplatinic acid toluene solution (platinum concentration 0.5 wt%) was added, and 164.9 g (0.85 mol) of compound (S-1) and 453.0 g (0.15 mol) of compound (S-2) (y were added dropwise over 1 hour.1 =40). The total molar number of hydrosilyl groups was 1 / 1 to the total molar number of alkenyl groups. After the addition was completed, the reaction solution was heated at 100°C and aged for 6 hours. Toluene was distilled off from the reaction solution in a vacuum to produce resin A-1. 1 H-NMR and 29 Analysis by Si-NMR spectroscopy (Bruker Corp.) and GPC identified the structure of Resin A-1. Resin A-1 had a Mw of 65,000 and a silicone content of 51.3 wt%.

[0174] Synthesis Example 2

[0175] Synthesis of Resin A-2

[0176] A 3L flask equipped with a stirrer, a thermometer, a nitrogen purge line and a reflux condenser was charged with 111.6 g (0.60 mol) of compound (S-3) and 156.8 g (0.40 mol) of compound (S-4), and then charged with 2,000 g of toluene and heated at 70° C. Thereafter, 1.0 g of a chloroplatinic acid toluene solution (platinum concentration 0.5 wt%) was added, and 135.8 g (0.70 mol) of compound (S-1) and 906.0 g (0.30 mol) of compound (S-2) (y were added dropwise over 1 hour. 1 =40). The total molar number of hydrosilyl groups was 1 / 1 to the total molar number of alkenyl groups. After the addition was completed, the reaction solution was heated at 100°C and aged for 6 hours. Toluene was distilled off from the reaction solution in vacuo to produce resin A-2. 1 H-NMR and 29 Si-NMR spectroscopy (Bruker Corp.) and GPC analysis identified the structure of Resin A-2. Resin A-2 had a Mw of 55,000 and a silicone content of 77.7 wt%.

[0177] Synthesis Example 3

[0178] Synthesis of Resin A-3

[0179] A 3L flask equipped with a stirrer, a thermometer, a nitrogen purge line and a reflux condenser was charged with 111.6 g (0.60 mol) of compound (S-3) and 106.0 g (0.40 mol) of compound (S-5), and then charged with 2,000 g of toluene and heated at 70° C. Thereafter, 1.0 g of a chloroplatinic acid toluene solution (platinum concentration 0.5 wt%) was added, and 174.6 g (0.90 mol) of compound (S-1) and 302.0 g (0.10 mol) of compound (S-2) (y were added dropwise over 1 hour. 1=40). The total molar number of hydrosilyl groups was 1 / 1 to the total molar number of alkenyl groups. After the addition was completed, the reaction solution was heated at 100°C and aged for 6 hours. Toluene was distilled off from the reaction solution in vacuo to produce resin A-3. 1 H-NMR and 29 Si-NMR spectroscopy (Bruker Corp.) and GPC analysis identified the structure of Resin A-3. Resin A-3 had a Mw of 50,000 and a silicone content of 59.6 wt%.

[0180] Synthesis Example 4

[0181] Synthesis of Resin A-4

[0182] A 3L flask equipped with a stirrer, a thermometer, a nitrogen purge line and a reflux condenser was charged with 392.0 g (1.00 mol) of compound (S-4), and then charged with 2,000 g of toluene and heated at 70° C. Thereafter, 1.0 g of a chloroplatinic acid toluene solution (platinum concentration 0.5 wt%) was added, and 155.2 g (0.80 mol) of compound (S-1) and 317.0 g (0.20 mol) of compound (S-2) (y were added dropwise over 1 hour. 1 =20). The total molar number of hydrosilyl groups was 1 / 1 to the total molar number of alkenyl groups. After the addition was completed, the reaction solution was heated at 100°C and aged for 6 hours. Toluene was distilled off from the reaction solution in a vacuum to produce resin A-4. 1 H-NMR and 29 Analysis by Si-NMR spectroscopy (Bruker Corp.) and GPC identified the structure of Resin A-4. Resin A-4 had a Mw of 23,000 and a silicone content of 36.7 wt%.

[0183] Synthesis Example 5

[0184] Synthesis of Resin A-5

[0185] A 3L flask equipped with a stirrer, a thermometer, a nitrogen purge line and a reflux condenser was charged with 274.4 g (0.70 mol) of compound (S-4) and 79.5 g (0.30 mol) of compound (S-5), and then charged with 2,000 g of toluene and heated at 70° C. Thereafter, 1.0 g of a chloroplatinic acid toluene solution (platinum concentration 0.5 wt%) was added, and 58.2 g (0.30 mol) of compound (S-1) and 1109.5 g (0.70 mol) of compound (S-2) (y were added dropwise over 1 hour. 1=20). The total molar number of hydrosilyl groups was 1 / 1 to the total molar number of alkenyl groups. After the addition was completed, the reaction solution was heated at 100°C and aged for 6 hours. Toluene was distilled off from the reaction solution in vacuo to produce resin A-5. 1 H-NMR and 29 Analysis by Si-NMR spectroscopy (Bruker Corp.) and GPC identified the structure of Resin A-5. Resin A-5 had a Mw of 42,000 and a silicone content of 72.9 wt%.

[0186] Synthesis Example 6

[0187] Synthesis of Resin A-6

[0188] A 3L flask equipped with a stirrer, a thermometer, a nitrogen purge line and a reflux condenser was charged with 55.8 g (0.30 mol) of compound (S-3), 117.6 g (0.30 mol) of compound (S-4) and 106.0 g (0.40 mol) of compound (S-5), and then charged with 2,000 g of toluene and heated at 70° C. Thereafter, 1.0 g of a chloroplatinic acid toluene solution (platinum concentration 0.5 wt%) was added, and 135.8 g (0.70 mol) of compound (S-1) and 475.5 g (0.30 mol) of compound (S-2) (y were added dropwise over 1 hour. 1 =20). The total molar number of hydrosilyl groups was 1 / 1 to the total molar number of alkenyl groups. After the addition was completed, the reaction solution was heated at 100°C and aged for 6 hours. Toluene was distilled off from the reaction solution in a vacuum to produce resin A-6. 1 H-NMR and 29 Analysis by Si-NMR spectroscopy (Bruker Corp.) and GPC identified the structure of Resin A-6. Resin A-6 had a Mw of 31,000 and a silicone content of 59.6 wt%.

[0189] Comparative Synthesis Example 1

[0190] Synthesis of acrylic resin 1

[0191] A flask equipped with a stirrer, a thermometer, an inert gas supply line, and a reflux condenser was charged with 70 g of propylene glycol monomethyl ether and 70 g of toluene and heated at 80° C. under a nitrogen atmosphere. While the flask was maintained at a temperature of 80±2° C., 90 g of methyl methacrylate, 10 g of methacrylic acid, and 2,2′-azobis(isobutyronitrile) were continuously added dropwise over 4 hours. At the end of the addition, stirring was continued at 80±2° C. for 6 hours to generate a solution of acrylic resin 1. Acrylic resin 1 had an Mw of 50,000.

[0192] [2] Preparation and evaluation of photosensitive resin compositions

[0193] Examples 1 to 15 and Comparative Examples 1 to 9

[0194] The photosensitive resin compositions of Examples 1 to 15 and Comparative Examples 1 to 9 were prepared by combining the components according to the formulations shown in Tables 1 and 2, stirring, mixing and dissolving them at room temperature.

[0195] Table 1

[0196]

[0197] Table 2

[0198]

[0199] In Tables 1 and 2, titanium dioxide is titanium dioxide R-105 (surface treated with a silicone compound, average particle size 300 nm, titanium oxide content 92 wt%) available from Chemours Co. Yttrium oxide is yttrium oxide UU type (average particle size 300 nm) available from Shin-Etsu Chemical Co., Ltd. Photoacid generator PAG-1, crosslinking agents D-1 to D-3, antioxidants E-1 and E-2, acrylic resin 2, and Irgacure OXE02 are identified as follows.

[0200] Photoacid generator B-1

[0201]

[0202] Crosslinking agent D-1 (Shin-Etsu Chemical Co., Ltd.)

[0203]

[0204] Crosslinking agent D-2 (Shikoku Chemicals Corp.)

[0205]

[0206] Crosslinking agent D-3 (Shikoku Chemicals Corp.)

[0207]

[0208] Antioxidant E-1: CHIMASSORB 119FL (BASF)

[0209]

[0210] Antioxidant E-2: Irganox 3114 (BASF)

[0211]

[0212] Acrylic resin 2: trade name DPCA-20, from Nippon Kayaku Co., Ltd. (ε-caprolactone-modified dipentaerythritol acrylate)

[0213]

[0214] Irgacure OXE02: Ethyl ketone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyl oxime) (BASF)

[0215] [4] Pattern formation test

[0216] (1) Pattern formation and evaluation

[0217] Each photosensitive resin composition was coated onto a glass substrate to a coating thickness of 10 μm using a spin coater. In order to evaporate the solvent, the substrate was placed on a hot plate and heated and dried at 110°C for 3 minutes. Using a contact lithography machine exposure tool, the photosensitive resin coating was exposed to 365nm radiation through a mask with a line-space pattern and a contact hole pattern. After exposure, the resin coating was baked (PEB) on a hot plate at 120°C for 3 minutes and cooled. This was followed by spray development in propylene glycol monomethyl ether acetate (PGMEA) for 300 seconds to form a pattern of the resin coating.

[0218] The patterned photosensitive resin coating on the substrate was post-cured in an oven at 190°C for 2 hours while the oven was purged with nitrogen. Under a scanning electron microscope (SEM), contact hole patterns of 50 μm, 30 μm, 20 μm, 10 μm and 5 μm were observed in cross section, and the smallest hole pattern in which the hole extended down to the bottom of the film was recorded as the maximum resolution. From the cross-sectional photograph, the verticality of the 50 μm contact hole pattern was evaluated, and the vertical pattern was rated as "◎ (excellent)", the slightly inverted tapered profile was rated as "○ (good)", the inverted tapered profile was rated as "△ (fair)" and the opening failure was rated as "× (poor)".

[0219] (2) Evaluation of reliability (adhesion, crack resistance)

[0220] Each of the substrates with the photosensitive resin coating after pattern formation and post-curing in the test (1) was cut into 10 mm square samples using a dicing saw (DISCO Co.'s DAD685, shaft speed 40,000 rpm, cutting rate 20 mm / sec) with a dicing blade. Ten samples of each embodiment were examined by a thermal cycle test (a test of keeping at -25°C for 10 minutes and keeping at 125°C for 10 minutes, the test was repeated 1,000 cycles). After the test, it was observed whether the resin coating was peeled off from the substrate and whether the resin coating was cracked. The sample was rated as "good" when all samples were not peeled off or cracked, "peeled" when one or more samples were peeled off, and "cracked" when one or more samples were cracked.

[0221] (3) Flexibility test

[0222] The film was wound around a shaft of 5 mm in diameter, held for 10 seconds, and unwound. The winding / unwinding operation was repeated 10 times, after which the film was checked for abnormalities. Intact samples were graded as "○ (good)" and cracked or defective samples were graded as "× (poor)".

[0223] (4) Light reflectance measurement

[0224] A 3 mm thick photosensitive resin film is formed from the photosensitive resin composition. Mask Aligner MA8 (SUSSMicroTec AG) is used to expose the resin film to light of a wavelength of 360 nm from a high pressure mercury lamp. The film is PEB and immersed in PGMEA. The resin film retained after these operations is then heated in an oven at 190 ° C for 2 hours to generate a cured film. The initial reflectivity of the cured film at a wavelength of 450 nm is measured. The cured film is kept at 150 ° C for 300 hours, after which its reflectivity at a wavelength of 450 nm is measured again. For this measurement, a spectrophotometer X-Rite 8200 (X-Rite, Inc.) is used.

[0225] The results are shown in Tables 3 and 4.

[0226] Table 3

[0227]

[0228] Table 4

[0229]

[0230] From the results, it was confirmed that the photosensitive resin composition within the scope of the present invention has good reliability, resolution and flexibility with respect to adhesion and crack resistance, and its cured film has satisfactory light-shielding properties in the form of a thin film.

[0231] Japanese Patent Application No. 2018-134158 is incorporated herein by reference.

[0232] While some preferred embodiments have been described, numerous modifications and variations are possible in light of the above teachings. It is therefore to be understood that the invention may be practiced otherwise than as specifically described without departing from the scope of the appended claims.

Claims

1. A photosensitive resin composition comprising (A) an organosilicon resin containing an acid-crosslinkable group, (B) a photoacid generator, and (C) titanium dioxide surface-treated with at least one compound selected from the group consisting of hydrated oxides of Al, Si and Zr, polyols and organosilicon compounds, wherein the acid crosslinkable groups are selected from epoxy groups, oxetane groups and vinyl ether groups, and wherein component (A) comprises a silicone resin consisting of repeating units having formulae (A1) to (A6): in, R 1 To R 4 are each independently a C1-C 20 A monovalent hydrocarbon group, m is independently an integer from 1 to 600, when m is an integer of at least 2, the group R 3 The same or different groups R 4 the same or different; a, b, c, d, e and f are numbers in the following range: 0≤a≤1, 0≤b≤1, 0≤c≤1, 0≤d≤1, 0≤e≤1, 0≤f≤1, 0 < c+d+e+f≤1 and a+b+c+d+e+f=1, X 1 is a divalent group having the formula (X1): Among them, R 11 To R 14 are each independently a C1-C 20 A monovalent hydrocarbon group, p is an integer from 1 to 600, when p is an integer of at least 2, the group R 13 The same or different groups R 14 Same or Different; R 15 and R 16 are each independently hydrogen or methyl, and x is each independently an integer from 0 to 7, X 2 is a divalent group having the formula (X2): Among them, Y 1 is a single bond, a methylene group, a propane-2,2-diyl group, a 1,1,1,3,3,3-hexafluoropropane-2,2-diyl group or a fluorene-9,9-diyl group, R 21 and R 22 Each independently is a C1-C4 alkyl or alkoxy group. When g is 2, the group R 21 The same or different, when h is 2, the group R 22 Same or Different; R 23 and R 24 are each independently hydrogen or methyl, y are each independently an integer from 0 to 7, g and h are each independently 0, 1 or 2, X 3 is a divalent group having the formula (X3): Among them, R 31 and R 32 are each independently hydrogen or methyl, z is each independently an integer from 0 to 7, R 33 It is a C1-C8 divalent hydrocarbon group which may contain an ester bond or an ether bond.

2. The photosensitive resin composition according to claim 1, wherein 0 < e+f≤1. 3 . The photosensitive resin composition according to claim 1 , wherein the titanium dioxide (C) has an average particle size of at most 1 μm. 4 . The photosensitive resin composition according to claim 1 , comprising 3 to 60% by weight of the titanium dioxide (C). The photosensitive resin composition according to claim 1 , further comprising (D) a crosslinking agent. The photosensitive resin composition according to claim 1 , further comprising (E) an antioxidant. 7 . The photosensitive resin composition according to claim 1 , further comprising (F) a solvent.

8. A pattern forming method comprising the following steps: (i) applying the photosensitive resin composition according to claim 1 onto a substrate to form a photosensitive resin coating thereon, (ii) exposing the photosensitive resin coating to radiation, and (iii) The exposed resin coating is developed with a developer.

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