Positive photosensitive resin composition containing a specific copolymer, a hardened film obtained from the resin composition, a microlens, and a method for manufacturing the same.

Abstract

This invention provides a novel positive photosensitive resin composition. The positive photosensitive resin composition of this invention comprises the following components (A), (B), and (C) and a solvent: (A) a copolymer containing (a1) a monomer represented by formula (1) below, (a2) a monomer containing an epoxy ring, and (a3) ​​a monomer containing a hydroxyl group with an acid dissociation constant pKa of 14 or more, and a copolymer without carboxyl or carboxylic anhydride groups; (B) a quinone diazide compound; (C) a photoacid generator; (where R0 represents a hydrogen atom or methyl, R1 represents a single bond or an alkyl group with 1 or 2 carbon atoms, R2 represents methyl, a represents 1 or 2, and b represents an integer from 0 to 2).

Description

Technical Field

[0001] This invention relates to a positive photosensitive resin composition, a hardened film obtained from the resin composition, a microlens, and a method for manufacturing the same. Prior Technology

[0002] Image elements such as CCD image sensors or CMOS image sensors, or display elements such as liquid crystal displays or organic EL displays, sometimes use tiny lenses called microlenses to improve performance. For example, the aforementioned image sensor incorporates microlenses to increase light collection efficiency, thereby enhancing sensor sensitivity.

[0003] One known method for fabricating microlenses is the etch-back method (e.g., Patent Document 1). That is, a resin layer for microlenses is formed on a color filter, a positive resist is coated onto the resin layer, a portion of the resist is exposed and developed, and, if necessary, heated to form a lens pattern. This lens pattern is then used as an etching mask for etch-back, transferring the lens pattern shape to the resin layer for microlenses to fabricate a microlens.

[0004] Furthermore, from the perspective of reducing manufacturing costs, the proposal suggests using the aforementioned positive resist directly as a microlens. In this case, it must possess both the characteristics of a resist and the characteristics of a microlens; therefore, it must not only be able to be positively patterned, but also be a photosensitive resin composition with excellent transparency and drug resistance in the formed microlens. Here, the shape of the microlens varies depending on the element design, and various shapes such as prisms, cylinders, frustums of pyramids, truncated cones, and spherical segments are required. When manufacturing spherical microlenses, after forming the pattern of a prism or frustum, a reflow (heating to flow; also known as melt flow or heat flow) method is known.

[0005] For example, Patent Document 2 proposes a photosensitive resin composition containing an alkali-soluble copolymer and a quinone diazide group compound. By using this composition, after forming a resin pattern through exposure and development, a microlens can be obtained by crosslinking the phenolic hydroxyl groups and epoxy groups by heating.

[0006] However, in recent years, the use of devices with low heat resistance, such as organic or flexible devices, has increased the demand for lower temperature processing steps. Consequently, there is a desire to produce positive photosensitive resin compositions with good performance for microlenses even in low-temperature processes. When fabricating truncated spherical microlenses, it is required that they can be fully reflowed even at low temperatures. Specifically, the upper limit temperature for these steps is required to be 150°C, and recently, 130°C has been demanded. The photosensitive resin composition described in Patent Document 2 uses the thermosetting of phenolic hydroxyl and epoxy groups; however, this thermosetting reaction typically requires high-temperature conditions exceeding 150°C, therefore, it is not suitable for low-temperature processes below 130°C.

[0007] Therefore, Patent Document 3 proposes a radiation-sensitive resin composition containing a compound that generates acid upon exposure to radiation, in addition to an alkali-soluble copolymer and a 1,2-quinone diazide compound. By using this composition, after forming a resin pattern through exposure and development, a strong acid is generated within the resin pattern upon re-exposure, allowing for cationic polymerization, thus enabling the process to be carried out at low temperatures. However, the monomers of the alkali-soluble copolymer used to form this composition contain carboxylic acids or carboxylic anhydrides, raising concerns about residue formation during patterning. If a portion of resin remains between patterns, it has a significant adverse effect on the device characteristics; therefore, a residue-free, positively patternable photosensitive resin composition is required.

[0008] Furthermore, Patent Document 4 proposes a radiation-sensitive resin composition containing compounds that produce acids with a pKa of 4.0 or lower, in addition to alkali-soluble polymers and quinone diazide compounds. While the alkali-soluble polymer maintains stability, it does not mention long-term reliability (HTS test, THS test, xenon arc test, etc.), leaving this characteristic unclear. The aforementioned organic or flexible devices lack practical reliability; therefore, it is desirable to produce a photosensitive resin composition for microlenses that does not deteriorate even after long-term reliability tests such as HTS (high temperature test), THS (high temperature and humidity test), and xenon arc test, and thus possesses good performance. [Previous Technical Documents] [Patent Literature]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 1-10666 [Patent Document 2] Japanese Patent Application Publication No. 2007-33518 [Patent Document 3] Japanese Patent Application Publication No. 2009-75329 [Patent Document 4] Japanese Patent Application Publication No. 2020-101659 Summary of the Invention

[0010] [The problem that the invention aims to solve] The present invention was made in accordance with the above circumstances. The purpose of the present invention is to provide a residue-free, positively patternable microlens that can be formed even in low-temperature processes below 130°C with the desired truncated spherical or hemispherical shape. The formed microlens have excellent transparency, drug resistance and long-term reliability. [Methods used to solve problems]

[0011] The present invention was completed by the inventors through careful examination in order to solve the aforementioned problems. The first state sample of the present invention is a positive photosensitive resin composition containing the following components (A), (B), (C) and a solvent. (A) Composition: A copolymer containing (a1) a monomer represented by formula (1) below, (a2) a monomer containing an epoxy ring, and (a3) ​​a monomer containing hydroxyl groups with an acid dissociation constant pKa of 14 or higher, and a copolymer that does not contain carboxyl or carboxylic anhydride groups. (B) Component: Quinone diazide compound (C) Component: Photoacid generator (In the formula, R0 represents a hydrogen atom or a methyl group, R1 represents a single bond or an alkyl group with 1 or 2 carbon atoms, R2 represents a methyl group, a represents 1 or 2, and b represents an integer from 0 to 2).

[0012] The monomer containing an epoxy ring mentioned above (a2) is the monomer represented by the following formula (2), and the monomer containing a hydroxyl group whose acid dissociation constant pKa is 14 or higher mentioned above (a3) ​​is, for example, the monomer represented by the following formula (3). (In the formula, R0 independently represents a hydrogen atom or a methyl group, R3 represents a divalent organogroup represented by formula (I) below, R4 represents a monovalent organogroup represented by formula (4) below or formula (5) below, and R5 represents a monovalent organogroup represented by formula (I') below.) (In the formula, c represents an integer from 0 to 3, d represents an integer from 1 to 3, e represents an integer from 2 to 6 independently, * represents a bond with the alkenyl group of the monomer represented by the aforementioned formula (2) or formula (3), and · represents a bond with the monovalent organogroup represented by the aforementioned formula (4) or formula (5).

[0013] The aforementioned component (A), for example, is a copolymer having structural units represented by formula (1a), formula (2a), and formula (3a) below. (In the formula, R0 represents a hydrogen atom or a methyl group, R1 represents a single bond or an alkyl group with 1 or 2 carbon atoms, R2 represents a methyl group, b represents an integer from 0 to 2, R4 represents a monovalent organic group represented by formula (4) or formula (5) below, and e represents an integer from 2 to 6).

[0014] The polystyrene of component (A) above has a converted weight average molecular weight, for example, 5,000 to 30,000.

[0015] The aforementioned component (C) is, for example, a nonionic photoacid generator. This nonionic photoacid generator is, for example, a photoacid generator represented by the following formula (6). (In the formula, R6 represents a hydrocarbon group or perfluoroalkyl group having 1 to 10 carbon atoms, and R7 represents a straight-chain alkyl or alkoxy group having 1 to 8 carbon atoms, or a branched alkyl or alkoxy group having 3 to 8 carbon atoms).

[0016] The positive photosensitive resin composition of the present invention may further contain the following component (D). (D) Component: Multifunctional epoxy compound.

[0017] The positive photosensitive resin composition of the present invention may further contain the following component (E). (E) Ingredient: Sensitive agent.

[0018] The positive photosensitive resin composition of the present invention is used, for example, for the fabrication of microlenses.

[0019] The second aspect of the present invention is a hardened film, which is obtained from the aforementioned positive photosensitive resin composition.

[0020] The third embodiment of the present invention is a microlens, which is made from the aforementioned positive photosensitive resin composition.

[0021] The fourth aspect of this invention is a method for fabricating a microlens, which includes the following steps: The process includes a coating step in which the aforementioned positive photosensitive resin composition is coated onto a substrate to form a resin film; a first exposure step in which at least a portion of the resin film is exposed after the coating step; a development step in which the exposed portion of the resin film is removed by a developer after the first exposure step to form a pattern of the unexposed portion of the resin film; a second exposure step in which the pattern is further exposed after the development step; and a baking step in which the pattern is heated at a temperature of 130°C or below after the second exposure step.

[0022] The process after the aforementioned development step and before the aforementioned second exposure step may include a reflow step in which the aforementioned pattern is heated at a temperature below 130°C.

[0023] The aforementioned substrate is, for example, a substrate on which a color filter is formed. [Invention Effects]

[0024] According to the present invention, since it simultaneously contains a specific copolymer (A) component, a quinone diazide compound (B) component, and a photoacid generator (C) component, it can provide a residue-free, positively patternable microlens that can be formed even in low-temperature processes below 130°C, with the desired truncated spherical or hemispherical shape. The formed microlens are positively patterned photosensitive resin compositions with excellent transparency, drug resistance, and long-term reliability. [Forms of Invention Implementation]

[0025] The positive photosensitive resin composition of the present invention will be described in more detail. [(A) ingredient] The positive photosensitive resin composition of the present invention contains component (A), which is a copolymer of (a1) a monomer represented by formula (1) below, (a2) a monomer containing an epoxy ring, and (a3) ​​a monomer containing hydroxyl groups with an acid dissociation constant pKa of 14 or higher, and is a copolymer that does not contain carboxyl groups or carboxylic anhydride groups. Here, the carboxylic anhydride group is a divalent group represented by -CO-O-CO-. (In the formula, R0 represents a hydrogen atom or a methyl group, R1 represents a single bond or an alkyl group with 1 or 2 carbon atoms, R2 represents a methyl group, a represents 1 or 2, and b represents an integer from 0 to 2).

[0026] (a1) Examples of monomers represented by formula (1) above include N-(2-hydroxyphenyl)(meth)acrylamide, N-(3-hydroxyphenyl)(meth)acrylamide, N-(4-hydroxyphenyl)(meth)acrylamide, N-(4-hydroxybenzyl)(meth)acrylamide, N-(4-hydroxyphenylethyl)(meth)acrylamide, N-(3,5-dimethyl-4-hydroxyphenyl)(meth)acrylamide, N-(3,5-dimethyl-4-hydroxybenzyl)(meth)acrylamide, and N-(3,5-dimethyl-4-hydroxyphenylethyl)(meth)acrylamide. These monomers may be used alone or in combination of two or more.

[0027] When the monomers are 100 parts by mass relative to the monomers in (a1), (a2) and (a3) ​​above, the proportion of monomers represented by the aforementioned formula (1) in (a1) is 5 to 60 parts by mass, more preferably 8 to 50 parts by mass, and even more preferably 10 to 40 parts by mass.

[0028] (a2) Monomers containing an epoxy ring and having at least one epoxy ring in their molecule, specific examples of which can be listed as monomers represented by the following formulas (2-1) to (2-16). These monomers can be used alone or in combination of two or more.

[0029] When the monomers (a1), (a2) and (a3) ​​mentioned above are 100 parts by mass, the proportion of monomers containing epoxy rings in (a2) is 20 to 80 parts by mass, more preferably 30 to 70 parts by mass, and even more preferably 40 to 60 parts by mass.

[0030] (a3) A monomeric system containing a hydroxyl group whose acid dissociation constant pKa is 14 or higher (the lowest value for polybasic acids) is a monomer with at least one hydroxyl group. Specific examples can be listed as monomers represented by the following formulas (3-1) to (3-25). The functional group whose acid dissociation constant pKa of this monomeric system is 13 or lower, for example, does not contain silanol, fluorool, maleimine, carboxyl, or phenolic hydroxyl groups. These individual units can be used alone or in combination of two or more.

[0031] When the monomers (a1), (a2) and (a3) ​​mentioned above are 100 parts by mass, the proportion of hydroxyl-containing monomers (a3) ​​with an acid dissociation constant pKa of 14 or above is 5 to 60 parts by mass, more preferably 8 to 50 parts by mass, and even more preferably 10 to 40 parts by mass.

[0032] The weight-average molecular weight (MW) of component (A) is calculated by gel permeation chromatography (GPC) to be 5,000 to 30,000, preferably 5,000 to 20,000, and even more preferably 5,000 to 15,000. Maintaining the weight-average molecular weight of component (A) within the aforementioned range does not impair drug tolerance and allows for the formation of a good pattern after development.

[0033] The glass transition temperature of component (A) is 70°C to 130°C. By using the glass transition temperature of component (A) within the aforementioned range, even in low-temperature processes below 130°C, it exhibits good reflowability and can be used to fabricate microlenses with the desired spherical or hemispherical shapes.

[0034] [(B) Component] The (B) component contained in the positive photosensitive resin composition of the present invention is not particularly limited as long as it is a compound having a 1,2-quinone diazide group. For example, a condensation product of a hydroxyl-containing compound and a 1,2-naphthoquinone diazidesulfonate halide can be used. Specifically, of the aforementioned hydroxyl-containing compounds, 10 mol% to 100 mol%, preferably 20 mol% to 95 mol%, of the hydroxyl groups are esterified with the aforementioned 1,2-naphthoquinone diazidesulfonate halide. The aforementioned condensation reaction can be performed using various known methods.

[0035] Examples of the aforementioned hydroxyl-containing compounds include those shown below. Dihydroxybenzophenones, such as 2,4-dihydroxybenzophenone; Trihydroxybenzophenones, including 2,3,4-trihydroxybenzophenone and 2,4,6-trihydroxybenzophenone; Tetrahydroxybenzophenones, including 2,4,2',4'-tetrahydroxybenzophenone, 2,3,4,3'-tetrahydroxybenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, 2,3,4,2'-tetrahydroxy-4'-methylbenzophenone, and 2,3,4,4'-tetrahydroxy-3'-methoxybenzophenone; Pentahydroxybenzophenones, including 2,3,4,2',4'-pentahydroxybenzophenone and 2,3,4,2',6'-pentahydroxybenzophenone; Hexahydroxybenzophenones, including 2,4,6,3',4',5'-hexahydroxybenzophenone and 3,4,5,3',4',5'-hexahydroxybenzophenone; 2,2-bis(4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,3,3-tris(4-hydroxyphenyl)butane, bis(2,4-dihydroxyphenyl)methane, bis(p-hydroxyphenyl)methane, tris(p-hydroxyphenyl)methane, 1,1,1-tris(p-hydroxyphenyl)ethane, bis(2,3,4-trihydroxyphenyl)methane, 2,2-bis(2,3,4-trihydroxyphenyl)propane, 1,1,3-tris(2,5-dimethyl-4-hydroxyphenyl)-3-phenylpropane, 4,4'-[1-[4-[1-[4-hydroxyphenyl]-1-methylethyl]phenyl]ethylidene]bisphenol, bis(2,5-dimethyl-4-hydroxyphenyl)-2-hydroxyphenylmethane, 3,3,3',3'-tetramethyl-1,1'-spirobiindene-5,6,7,5',6',7'-hexanol, and 2,2,4-trimethyl-7,2',4'-trihydroxyflavan, etc. (polyhydroxyphenyl) alkanes; Phenol, o-cresol, m-cresol, p-cresol, hydroquinone, resorcinol, catechol, methyl gallate, ethyl gallate, 2-methyl-2-(2,4-dihydroxyphenyl)-4-(4-hydroxyphenyl)-7-hydroxychromane, 1-[1-(3-{1-(4-hydroxyphenyl)-1-methylethyl}-4,6-dihydroxyphenyl)-1-methylethyl]-3-(1-(3-{1-(4-hydroxyphenyl)-1-methylethyl}-4,6-dihydroxyphenyl)-1-methylethyl)benzene, and other compounds such as 4,6-bis{1-(4-hydroxyphenyl)-1-methylethyl}-1,3-dihydroxyphenyl. Among these compounds, 2,3,4,4'-tetrahydroxybenzophenone, 1,1,1-tris(p-hydroxyphenyl)ethane, and 4,4'-[1-[4-[1-[4-hydroxyphenyl]-1-methylethyl]phenyl]ethylidene]bisphenol are preferred.

[0036] The aforementioned 1,2-naphthoquinone diazidosulfonic acid halide is preferably 1,2-naphthoquinone diazidosulfonic acid chloride, more preferably 1,2-naphthoquinone-2-diazido-4-sulfonic acid chloride and 1,2-naphthoquinone-2-diazido-5-sulfonic acid chloride, and even more preferably 1,2-naphthoquinone-2-diazido-5-sulfonic acid chloride.

[0037] (B) The compound of the component can be used alone or in combination of two or more.

[0038] When the content of component (B) in the positive photosensitive resin composition of the present invention is 5 to 100 parts by mass relative to 100 parts by mass, more preferably 10 to 60 parts by mass, and even more preferably 15 to 40 parts by mass, relative to 100 parts by mass of component (A). By keeping the content of component (B) within the above range, the sensitivity will not decrease significantly, and the difference in solubility of the alkaline developer between the exposed and unexposed areas can be large, so that positive patterning can be achieved with relatively low exposure.

[0039] [(C) Component] The (C) component contained in the positive photosensitive resin composition of the present invention is not particularly limited as long as it is a compound that can generate an acid with an acid dissociation constant pKa of 4 or less by exposure. Examples include ionic photoacid generators and nonionic photoacid generators.

[0040] Ionic photoacid generators may include, for example, the following products and compounds. Adeka Arkls (registered trademark) SP-056, same as SP-171 (and above, manufactured by ADEKA), CPI (registered trademark)-100B(40), same as -100P, same as -101A, same as -110A, same as -110B, same as -110P, same as -200K, same as -210S, same as -300, same as -310B, same as -310FG, same as -400, same as -410B, same as -410S, VC-1FG, ES-1B (and above, manufactured by san-apro), TPS-TF, TPS-CS, TPS-PFBS (and above, manufactured by Toyo Gosei Kogyo), TP Aryl strontium salts including S-102, TPS-103, TPS-105, TPS-106, TPS-109, TPS-200, TPS-300, TPS-1000, HDS-109, MDS-103, MDS-105, MDS-109, MDS-205, MDS-209, BDS-109, MNPS-109, DTS-102, DTS-103, DTS-105, DTS-200, NDS-103, NDS-105, NDS-155, and NDS-165 (all manufactured by Midori Chemical Co., Ltd.); Adeka Arkls (registered trademark) SP-140 (or above, manufactured by ADEKA), IK-1, IK-1PC (80), IK-1FG (or above, manufactured by san-apro), DTBPI-PFBS (or above, manufactured by Toyo Gosei Kogyo), DPI-105, DPI-106, DPI-109, DPI-201, BI-105, MPI-105, MPI-106, MPI-109, BBI-102, BBI-103, BBI-105, BBI-106, BBI-109, BBI-110, BBI-200, BBI-201, BBI-300, and BBI-301 (or above, manufactured by Midori Chemicals) and other aryl ferrous salts.

[0041] Nonionic photoacid generators may be used, for example, the following products and compounds. N-sulfonoxyphenylimine derivatives, including Adeka Arkls (registered trademark) SP-082, SP-606 (and above, manufactured by ADEKA), NA-CS1, NP-TM2, NP-SE10 (and above, manufactured by san-apro), SI-105, SI-106, PI-106, NDI-101, NDI-105, NDI-106, NDI-109, NDI-1001, NDI-1004, NAI-100, NAI-101, NAI-105, NAI-106, NAI-109, NAI-1002, NAI-1003, and NAI-1004 (and above, manufactured by Midori Chemical). IRGACURE (registered trademark) PAG103, PAG121, PAG203 (and above, manufactured by BASF JAPAN), PAI-01, PAI-101, PAI-106, PAI-1001, PAI-1002, PAI-1003, and PAI-1004 (and above, manufactured by Midori Chemicals, etc.) are oxime sulfonates. Triazine derivatives including TAZ-100, TAZ-101, TAZ-102, TAZ-103, TAZ-104, TAZ-107, TAZ-108, TAZ-109, TAZ-110, TAZ-113, TAZ-114, TAZ-118, TAZ-122, TAZ-123, TAZ-203, and TAZ-204 (all manufactured by Midori Chemical Co., Ltd.).

[0042] Among these ionic and nonionic photoacid generators, from the viewpoint of preserving stability or sensitivity, nonionic photoacid generators are preferred, more preferably N-sulfonoxyimids, and even more preferably compounds represented by the aforementioned formula (6). Specific examples of compounds represented by the aforementioned formula (6) can be listed as compounds represented by the following formulas (6-1) to (6-28).

[0043] (C) The compound of component (C) may be used alone or in combination of two or more.

[0044] Relative to 100 parts by weight of component (A), the content of component (C) in the positive photosensitive resin composition of the present invention is 0.1 parts by weight to 10 parts by weight, preferably 0.5 parts by weight to 5 parts by weight. Setting the content of component (C) within the above range will not impair transparency and can improve drug tolerance.

[0045] [(D) component] The positive photosensitive resin composition of the present invention contains component (D) as any component, as long as it is a compound having at least two epoxy rings in the molecule, without particular limitation, and products and compounds such as those shown below can be used. EPICLON (registered trademark) 830, 830-S, 835, 840, 840-S, 850, 850-S, 850-LC, HP-820 (and above, manufactured by DIC), DENACOL (registered trademark) EX-201, EX-211, EX-212, EX-252, EX-810, EX-811, EX-821, EX-830, EX-832 Same as EX-841, EX-850, EX-851, EX-861, EX-920, EX-931, EX-991L, EX-313, EX-314, EX-321, EX-321L, EX-411, EX-421, EX-512, EX-521, EX-612, EX-614, EX-614B, EX-622 (and above, nagase) chemtex (manufactured by Mitsubishi Chemical Co., Ltd.), jER (registered trademark) 152, same as 630, same as 825, same as 827, same as 828, same as 828EL, same as 828US, same as 828XA (and above, manufactured by Mitsubishi Chemical Co., Ltd.), TETRAD (registered trademark) -C, same as -X (and above, manufactured by Mitsubishi Gas Chemical Co., Ltd.), CELLOXID (registered trademark) 2021P, same as 2081, EPOLEAD (registered trademark) GT401 (and above,(Manufactured by DAICEL), EPOTOHTO (registered trademark) YD-115, YD-115CA, YD-127, YD-128, YD-128G, YD-128S, YD-128CA, YD-8125, YD-825GS, YDF-170, YDF-170N, YDF-8170C, YDF-870GS, ZX-1059, YH-404, YH-434, YH-434L, YH-513, YH-523, ST-3000 (and above, manufactured by NIPPON STEEL Chemical & Material Co., Ltd.), ADEKA RESIN (registered trademark) EP-4100, EP-4100G, EP-4100E, EP-4100TX, EP-4300E, EP-4100, EP-4400, EP-4520S, EP-4530, EP-4901, EP-4901E, EP-4000, EP-4005, EP-7001, EP-4080E, EPU-6, EPU-7N, EPU-11F, EPU-15F, EPU-1395, EPU-73B, EPU-17, EPU-17T-6, EPR-1415-1, EPR-2000, EPR-2007, ADEKA GLYCIROL (registered trademark) ED-503, ED-503G, ED-506, ED-523T, ED-505 (all manufactured by ADEKA), SUMI-EPOXY (registered trademark) ELM-434, ELM-434L, ELM-434VL, ELM-100, ELM-100H (all manufactured by Sumitomo Chemical), EpoliteM-1230, 40E, 100E, 200E, 400E, 70P, 200P, 400P, 1500NP, 1600, 80MF, 4000, 3002(N) (all manufactured by Kyoei Chemical), and THI-DE (manufactured by ENEOS), etc., are multifunctional epoxy resins.

[0046] (D) The compound can be used alone or in combination of two or more.

[0047] When the positive photosensitive resin composition of the present invention contains component (D), the content of component (D) is 5 to 100 parts by mass relative to 100 parts by mass of component (A), preferably 10 to 50 parts by mass. Setting the content of component (D) within the above range can improve drug tolerance.

[0048] [(E) component] The (E) component contained in the positive photosensitive resin composition of the present invention is not particularly limited as long as it is a substance whose energy can be transferred to other substances by irradiated light. Examples include p-toluquinone, 1-phenyl-1,2-propanedione, phenanthrene, anthracene, 9,10-diethoxyanthracene, 9,10-diethoxyanthracene, 9,10-diethoxyanthracene, 9,10-diethoxyanthracene, 3,7-diethoxyanthracene, pyrene, perylene, xanthone, thioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, and 2-isopropylthioxanthone.

[0049] (E) The compound can be used alone or in combination of two or more.

[0050] When the positive photosensitive resin composition of the present invention contains component (E), the content of component (E) is 0.01 to 5 parts by mass relative to 100 parts by mass of component (A), preferably 0.05 to 3 parts by mass, and more preferably 0.1 to 1 part by mass. When the content of component (E) is set within the above range, it has been found that transparency is not impaired. Component (C) effectively enhances the sensitization of photoacid generators and can improve drug tolerance.

[0051] [solvent] The solvent contained in the positive photosensitive resin composition of the present invention is not particularly limited as long as it can dissolve components (A) to (C) and any components added if necessary. For example, all organic solvents such as hydrocarbons, halogenated hydrocarbons, ethers, alcohols, aldehydes, ketones, esters, amides, and nitriles can be used.

[0052] The aforementioned hydrocarbons include, for example, n-pentane, cyclopentane, methylcyclopentane, n-hexane, isohexane, cyclohexane, methylcyclohexane, ethylcyclohexane, n-heptane, benzene, toluene, o-xylene, m-xylene, p-xylene, and mesitylene.

[0053] Examples of the aforementioned halogenated hydrocarbons include dichloromethane, chloroform, carbon tetrachloride, chloroethane, dichloroethane, trichloroethane, tetrachloroethane, hexachloroethane, dichloroethylene, trichloroethylene, tetrachloroethylene, chlorobenzene, hydrofluorocarbons, and perfluorocarbons.

[0054] The aforementioned ethers include, for example, diethyl ether, di-n-propyl ether, diisopropyl ether, di-n-butyl ether, diisobutyl ether, di-tert-butyl ether, di-n-pentyl ether, diisopentyl ether, di-n-hexyl ether, methyl-n-propyl ether, methyl isopropyl ether, ethyl-n-propyl ether, ethyl isopropyl ether, n-butyl methyl ether, isobutyl methyl ether, tert-butyl methyl ether, n-butyl ethyl ether, isobutyl ethyl ether, tert-butyl ethyl ether, methyl-n-pentyl ether, cyclopentyl methyl ether, n-hexyl methyl ether, cyclohexyl methyl ether, etc. Ethers, tetrahydrofuran, tetrahydropyran, 1,3-dioxane, 1,4-dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol dibutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dibutyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, dipropylene glycol dibutyl ether, tripropylene glycol dimethyl ether, tripropylene glycol diethyl ether and tripropylene glycol dibutyl ether, etc.

[0055] Examples of the aforementioned alcohols include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 3-methyl-2-butanol, neopentanol, cyclopentanol, methylcyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, cyclohexanol, methylcyclohexanol, 1-heptanol, 2-heptanol, 3-heptanol, 4-heptanol, 1-octanol, 2-octanol, 3-octanol, 4-octanol, 2-ethyl-1-hexanol, benzyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, and triethylene glycol monoethyl ether. Triethylene glycol monopropyl ether, triethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether and tripropylene glycol monobutyl ether, etc., are monohydric alcohols, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,3-propanediol. propylene glycol, dipropylene glycol, tripropylene glycol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,5-pentanediol, 1,4-pentanediol, 1,3-pentanediol, 1,2-pentanediol, 3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol and 1,2-hexanediol, etc., diols, and triols, such as glycerol.

[0056] Examples of the aforementioned aldehydes include acetaldehyde, propionaldehyde, 2-methyl-1-propionaldehyde, butyraldehyde, 3-methylbutyraldehyde, pentanal, and benzaldehyde.

[0057] Examples of the aforementioned ketones include acetone, 2-butanone, 2-pentanone, 3-pentanone, cyclopentanone, 2,4-pentanedione, 4-methyl-2-pentanone, 4-hydroxy-4-methyl-2-pentanone, cyclohexanone, and 2-heptanone.

[0058] The aforementioned esters may include, for example, methylformate, ethylformate, n-propylformate, isopropylformate, n-butylformate, isobutylformate, tert-butylformate, n-pentylformate, isopentylformate, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, tert-butyl acetate, n-pentyl acetate, isopentyl acetate, cyclopentyl acetate, n-hexyl acetate, isohexyl acetate, cyclohexyl acetate, n-heptyl acetate, isoheptyl acetate, n... - Octyl acetate, Isooctyl acetate, Benzyl acetate, Ethylene glycol monomethyl ether acetate, Ethylene glycol monoethyl ether acetate, Ethylene glycol monobutyl ether acetate, Ethylene glycol diacetate, Diethylene glycol monomethyl ether acetate, Diethylene glycol monoethyl ether acetate, Diethylene glycol monobutyl ether acetate, Triethylene glycol monomethyl ether acetate, Triethylene glycol monoethyl ether acetate, Triethylene glycol monobutyl ether acetate, Propylene glycol monomethyl ether acetate, Propylene glycol monoethyl ether acetate, Propylene glycol monobutyl ether acetate, Propylene glycol diacetate, Dipropylene glycol monomethyl ether acetate, Dipropylene glycol monoethyl ether acetate, Dipropylene glycol monobutyl ether acetate, Tripropylene glycol monomethyl ether acetate Ether acetate, tripropylene glycol monoethyl ether acetate, tripropylene glycol monobutyl ether acetate, methyl propionate, ethyl propionate, n-propyl propionate, isopropyl propionate, n-butyl propionate, isobutyl propionate, tert-butyl propionate, methyl butyrate, ethyl butyrate, n-propyl butyrate, isopropyl butyrate, n-butyl butyrate, isobutyl butyrate, tert-butyl butyrate, methyl isobutyrate, ethyl isobutyrate, n-propyl isobutyrate, isopropyl isobutyrate, n-butyl isobutyrate, isobutyl isobutyrate, tert-butyl isobutyric acid Esters, methyl lactate, ethyl lactate, n-propyl lactate, isopropyl lactate, n-butyl lactate, isobutyl lactate, tert-butyl lactate, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, tert-butyl acetate, dimethyl malonate, diethyl malonate, triacetin, γ-butyrolactone, γ-valerolactone, γ-caprolactone, δ-valerolactone, δ-caprolactone, and ε-caprolactone, etc.

[0059] Examples of the aforementioned acetamides include N,N-dimethylmethamide, N,N-dimethylacetamide, N,N-dimethylisobutylamide, N-methylpyrrolidone, and N-ethylpyrrolidone.

[0060] Examples of the aforementioned nitrile compounds include acetonitrile, propionitrile, and butyronitrile.

[0061] These solvents can be used alone or in combination of two or more.

[0062] Among these solvents, those preferred for improving the flatness of the hardened film formed by coating the positive photosensitive resin composition of the present invention onto a substrate are propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether, propylene glycol monopropyl ether, 2-heptanone, ethyl lactate, n-butyl lactate, cyclopentanone, and cyclohexanone.

[0063] [Surfactants, other additives] The positive photosensitive resin composition of the present invention may contain surfactants in any way to improve coatability. Surfactants can be categorized as follows: nonionic surfactants such as polyoxyethylene alkyl ethers (e.g., polyoxyethylene lauryl ether, polyoxyethylene octadecyl ether, polyoxyethylene hexadecyl ether, polyoxyethylene oleyl ether); polyoxyethylene alkyl aromatic ethers (e.g., polyoxyethylene octylphenyl ether, polyoxyethylene nonylphenyl ether); polyoxyethylene / polyoxypropylene block copolymers; sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan monooleate, sorbitan trioleate, and sorbitan tristearate); and polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan tristearate. EFTOP (registered trademark) is also mentioned. EF301, EF303, EF352 (and above, manufactured by Mitsubishi Materials Electronic Chemicals, Ltd.), Megafac (registered trademark) F-171, F-173, R-30, R-40, R-40-LM (and above, manufactured by DIC, Ltd.), FluoradFC430, FC431 (and above, manufactured by Sumitomo 3M, Ltd.), Asahiguard (registered trademark) AG710, Surflon (registered trademark) S-382, SC101, SC102, SC103, SC1 04. Fluorinated surfactants such as SC105, SC106 (manufactured by AGC), FTX-206D, FTX-212D, FTX-218, FTX-220D, FTX-230D, FTX-240D, FTX-212P, FTX-220P, FTX-228P, FTX-240G, etc. (manufactured by NEOS), and organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Industry Co., Ltd.). These surfactants can be used alone or in combination of two or more.

[0064] When the positive photosensitive resin composition of the present invention contains a surfactant, the surfactant content is 0.001 to 3 parts by mass, more preferably 0.005 to 1 part by mass, and even more preferably 0.01 to 0.5 parts by mass, relative to 100 parts by mass of the total solids component after removing the solvent in the positive photosensitive resin composition.

[0065] The positive photosensitive resin composition of the present invention may, if necessary, contain additives such as curing aids, antioxidants, ultraviolet absorbers, plasticizers, and adhesion promoters, without impairing the effects of the present invention.

[0066] [Preparation method of positive photosensitive resin composition] The method for preparing the positive photosensitive resin composition of the present invention is not particularly limited. Examples include dissolving components (A) to (C) and any other components in a solvent to form a homogeneous solution. Furthermore, if necessary, the solution can be filtered using a filter with a pore size of 0.1 μm to 10 μm.

[0067] [Methods for fabricating microlenses] This section describes an example of fabricating a microlens using the positive photosensitive resin composition of the present invention. <Coating Steps> The positive photosensitive resin composition of the present invention is coated onto a substrate (e.g., a semiconductor substrate, glass substrate, quartz substrate, plastic substrate, silicon wafer, and substrates of elements such as various metal films or color filters formed on their surfaces) using a suitable coating method such as a spin coater or coating machine. Preferably, it is then pre-baked using a heating means such as an oven or heating plate to remove solvent and form a resin film. The pre-baking conditions can be appropriately selected from a baking temperature of 60°C to 130°C and a baking time of 20 seconds to 30 minutes. The thickness of the formed resin film is 0.1 μm to 10 μm, preferably 0.2 μm to 5 μm.

[0068] <First Exposure Step> Following the aforementioned coating step, at least a portion of the formed resin film is exposed to light through a specific mask. The light used for exposure can be, for example, g-line, i-line, KrF excimer laser, or ArF excimer laser. The exposure dose is suitably selected from the range of 20 mJ / cm² to 2000 mJ / cm².

[0069] <Developing Steps> Following the aforementioned first exposure step, the exposed portions of the resin film are removed by a developing solution, forming a pattern of the unexposed portions of the resin film. The developing method is not particularly limited, and examples include immersion, paddle, and spray methods. The developing conditions are suitable, selected from a developing temperature range of 5°C to 50°C and a developing time range of 10 seconds to 300 seconds. The developing solution used is not particularly limited as long as it can remove the exposed portions; examples include alkaline aqueous solutions of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate, sodium phosphate, potassium phosphate, ammonia, tetramethylammonium hydroxide (TMAH), and tetraethylammonium hydroxide (TEAH). Furthermore, solutions with appropriate amounts of surfactants or organic solvents added to the alkaline aqueous solution can also be used as developing solutions. These developing solutions can be used alone or in combination of two or more.

[0070] After development, the developer can be removed with a cleaning solution. After development or cleaning, to remove any residual developer or cleaning solution, the machine can be dried by rotating it with a rotary coater or similar rotatable device, or by blowing compressed air or compressed nitrogen.

[0071] <Reflow Steps> The pattern formed after the aforementioned development step may also include a reflow step, which involves heating the image using an oven or heating plate, before the second exposure step described later. The reflow conditions are suitable, selected from a baking temperature of 80°C to 130°C and a baking time of 1 minute to 90 minutes. Furthermore, even without omitting the reflow step, truncated spherical or hemispherical microlenses can be fabricated; however, by including the reflow step, truncated spherical or hemispherical microlenses can be fabricated at a lower temperature.

[0072] <Second Exposure Step> Following the aforementioned development step, or the aforementioned reflow step, the aforementioned pattern is further exposed. The exposure light can be, for example, g-line, i-line, KrF excimer laser, or ArF excimer laser. The exposure dose is appropriately selected from the range of 100 mJ / cm² to 5000 mJ / cm².

[0073] <Post-baking steps> Following the second exposure step, the aforementioned pattern is heated using a heating method such as an oven or a heating plate. The subsequent baking conditions are suitable and selected from a baking temperature of 80°C to 130°C and a baking time of 1 minute to 90 minutes. Implementation

[0074] [Example] The present invention will be described in more detail below with examples, but the present invention is not limited to the following examples.

[0075] The apparatus and conditions for determining the converted weight average molecular weight (MW) of polystyrene copolymers are as follows. Equipment: GPC system manufactured by Japan Spectrophotometer Co., Ltd. Tubing: Shodex (registered trademark) KF-804L and KF-803L Tube oven: 40℃ Flow rate: 1 mL / min Dissolution solution: Tetrahydrofuran Sample concentration: 10 mg / mL Sample injection volume: 20 μL Standard material: Monodisperse polystyrene Detector: Differential refractometer

[0076] The compounds used in the examples and comparative examples are as follows. <(B) Ingredients> B-1: A condensate of 1,5 moles of bisphenol A and 1,2-naphthoquinone-2-diazido-5-sulfonic acid chloride. <(C) Ingredients> C-1: Adeka Arkls (registered trademark) SP-606 (manufactured by ADEKA) C-2: CPI-110P (San-Apro (stock) system) <(D) Components> D-1: EPOLEAD (registered trademark) GT401 (manufactured by Daicel, Inc.) <(E) Components> E-1:2-Isopropylthioxanthone (manufactured by Tokyo Chemical Industry Co., Ltd.) <surfactants> R-40: Megafac (registered trademark) R-40 (DIC (stock) company)

[0077] [(A) Component Synthesis] <Synthesis example 1> A stir bar and 50g of propylene glycol monomethyl ether as a solvent were placed in a flask and immersed in a heated oil bath at 87°C. Next, a solution containing 30g of N-(4-hydroxyphenyl)methacrylamide (as shown in formula (1) above), 60g of 3,4-epoxycyclohexylmethyl methacrylate (as shown in formula (2-6) above), 10g of 2-hydroxyethyl methacrylate (as shown in formula (3-5) above), a monomer containing an epoxy ring (as shown in formula (2-6) above), 4.5g of 2,2'-azobisisobutyronitrile (as shown in formula (3-5) above), and 194g of propylene glycol monomethyl ether as a solvent was placed in a dropping funnel connected to the aforementioned flask. After nitrogen substitution, the solution was dropped dropwise over 3 hours with stirring. After the dropping was completed, the reaction was allowed to continue for 15 hours to obtain a copolymer solution (solid content concentration 30% by mass). The resulting copolymer has a polystyrene equivalent weight average molecular weight (MW) of 8,000. Hereinafter, the copolymer obtained in Synthesis Example 1 will be referred to as A-1.

[0078] <Synthesis example 2> Except for the use of 25g of N-(4-hydroxyphenyl)methacrylamide, 15g of 2-hydroxyethyl methacrylate, and 4.6g of 2,2'-azobisisobutyronitrile, a copolymer solution (solids concentration 30% by mass) was obtained by the same method as in Synthesis Example 1. The polystyrene equivalent weight average molecular weight (MW) of the obtained copolymer was 8,000. Hereinafter, the copolymer obtained in Synthesis Example 2 will be referred to as A-2 in this specification.

[0079] <Synthesis example 3> Except for the use of 20g of N-(4-hydroxyphenyl)methacrylamide, 20g of 2-hydroxyethyl methacrylate, and 4.7g of 2,2'-azobisisobutyronitrile, a copolymer solution (solids concentration 30% by mass) was obtained by the same method as in Synthesis Example 1. The polystyrene equivalent weight average molecular weight (MW) of the obtained copolymer was 8,000. Hereinafter, the copolymer obtained in Synthesis Example 3 will be referred to as A-3 in this specification.

[0080] <Synthesis example 4> A stir bar and 50g of propylene glycol monomethyl ether as a solvent were placed in a flask and immersed in a heated oil bath at 80°C. Next, a solution containing 40g of N-(4-hydroxyphenyl)methacrylamide as a monomer, 60g of 3,4-epoxycyclohexylmethyl methacrylate, 4.4g of 2,2'-azobisisobutyronitrile as a thermal free radical generator, and 194g of propylene glycol monomethyl ether as a solvent was placed in a dropping funnel connected to the aforementioned flask. After nitrogen substitution, the mixture was dropped dropwise over 3 hours with stirring. After the dropping was completed, the reaction was allowed to continue for 15 hours to obtain a copolymer solution (solids concentration 30% by mass). The polystyrene of the obtained copolymer had a weight-average molecular weight (MW) of 11,000. Hereinafter, the copolymer obtained in Synthesis Example 4 will be referred to as A-4.

[0081] <Synthesis example 5> A stir bar and 90g of propylene glycol monomethyl ether as a solvent were placed in a flask and immersed in a heated oil bath at 70°C. Next, a solution containing 10g of acrylic acid, 30g of 4-hydroxybutyl acrylate, and 60g of styrene as monomers, 4.5g of 2,2'-azobisisobutyronitrile (2,2'-azobisisobutyronitrile) as a thermal free radical generator, and 105g of propylene glycol monomethyl ether as a solvent was placed in a dropping funnel connected to the aforementioned flask. After nitrogen substitution, the mixture was added dropwise over 3 hours with stirring. After the dropwise addition was complete, the reaction was allowed to proceed for another 15 hours to obtain a copolymer solution (solids concentration 35% by mass). The polystyrene of the obtained copolymer had a weight-average molecular weight (MW) of 18,000. Hereinafter, the copolymer obtained in Synthesis Example 5 will be referred to as A-5 in this specification.

[0082] [Preparation of Positive Photosensitive Resin Composition] <Example 1> 70.0 g of copolymer A-1 obtained from Synthesis Example 1 (as component A) (21.0 g of solids) was prepared, 4.8 g of B-1 (as component B) was prepared, 0.2 g of C-1 (as component C) was prepared, 6.3 g of D-1 (as component D) was prepared, 0.01 g of R-40 (as surfactant) was prepared, 6.6 g of propylene glycol monomethyl ether (as solvent) and 23.8 g of propylene glycol monomethyl ether acetate (as solvent) were prepared to form a homogeneous solution. Then, the solution was filtered using a polyethylene microfilter with a pore size of 0.10 μm to obtain a positive photosensitive resin composition (solids concentration 29% by mass).

[0083] <Example 2> 70.0 g of copolymer A-1 obtained from Synthesis Example 1 (as component A) (21.0 g of solids) was prepared, 4.8 g of B-1 (as component B) was prepared, 0.3 g of C-2 (as component C) was prepared, 6.3 g of D-1 (as component D) was prepared, 0.01 g of R-40 (as surfactant) was prepared, 6.8 g of propylene glycol monomethyl ether (as solvent) and 23.9 g of propylene glycol monomethyl ether acetate (as solvent) were prepared to form a homogeneous solution. Then, the solution was filtered using a polyethylene microfilter with a pore size of 0.10 μm to obtain a positive photosensitive resin composition (solids concentration 29% by mass).

[0084] <Example 3> 70.0 g of copolymer A-2 obtained from Synthesis Example 2 (as component A) (21.0 g of solids) was prepared, along with 4.8 g of B-1 (as component B), 0.2 g of C-1 (as component C), 6.3 g of D-1 (as component D), 0.01 g of R-40 (as surfactant), 6.6 g of propylene glycol monomethyl ether (as solvent), and 23.8 g of propylene glycol monomethyl ether acetate (as solvent), to form a homogeneous solution. The solution was then filtered using a polyethylene microfilter with a pore size of 0.10 μm to obtain a positive photosensitive resin composition (solids concentration 29% by mass).

[0085] <Example 4> 70.0 g of copolymer A-3 obtained from Synthesis Example 3 (as component A) (21.0 g of solids) was prepared, 4.8 g of B-1 (as component B) was prepared, 0.2 g of C-1 (as component C) was prepared, 6.3 g of D-1 (as component D) was prepared, 0.01 g of R-40 (as surfactant) was prepared, 30.2 g of propylene glycol monomethyl ether (as solvent) and 79.2 g of propylene glycol monomethyl ether acetate (as solvent) were prepared to form a homogeneous solution. Then, the solution was filtered using a polyethylene microfilter with a pore size of 0.10 μm to obtain a positive photosensitive resin composition (solids concentration 17% by mass).

[0086] <Example 5> 70.0 g of copolymer A-3 obtained from Synthesis Example 3 (as component A) (21.0 g of solids) was prepared, 4.8 g of B-1 (as component B) was prepared, 0.2 g of C-1 (as component C) was prepared, 0.01 g of R-40 (as surfactant) was prepared, 25.1 g of propylene glycol monomethyl ether (as solvent) and 74.1 g of propylene glycol monomethyl ether acetate (as solvent) were prepared to form a homogeneous solution. Then, the solution was filtered using a polyethylene microfilter with a pore size of 0.10 μm to obtain a positive photosensitive resin composition (solids concentration 15% by mass).

[0087] <Example 6> 84.0 g of copolymer A-3 obtained from Synthesis Example 3 (as component A) (25.2 g of solids) was prepared, 5.8 g of B-1 (as component B) was prepared, 0.2 g of C-1 (as component C) was prepared, 7.6 g of D-1 (as component D) was prepared, 0.05 g of E-1 (as component E) was prepared, 0.01 g of R-40 (as surfactant) was prepared, 36.2 g of propylene glycol monomethyl ether (as solvent) and 95.0 g of propylene glycol monomethyl ether acetate (as solvent) were prepared to form a homogeneous solution. Then, the solution was filtered using a polyethylene microfilter with a pore size of 0.10 μm to obtain a positive photosensitive resin composition (solids concentration 17% by mass).

[0088] <Comparative Example 1> 70.0 g of copolymer A-4 (21.0 g solids) obtained from Synthesis Example 4, which is not equivalent to component (A), was prepared. 4.8 g of B-1 (component B), 0.2 g of C-1 (component C), 6.3 g of D-1 (component D), 0.01 g of R-40 (surfactant), 9.4 g of propylene glycol monomethyl ether (solvent), and 25.0 g of propylene glycol monomethyl ether acetate were prepared to form a homogeneous solution. The solution was then filtered using a polyethylene microfilter with a pore size of 0.10 μm to obtain a positive photosensitive resin composition (solids concentration 28% by mass).

[0089] <Comparative Example 2> 60.0 g of copolymer A-5 (21.0 g of solids) obtained from Synthesis Example 5, which is not equivalent to component (A), was prepared; 4.8 g of B-1 (component B), was prepared; 0.2 g of C-1 (component C), was prepared; 10.5 g of D-1 (component D), was prepared; 0.01 g of R-40 (surfactant), was prepared; 3.8 g of propylene glycol monomethyl ether (PMME) and 35.1 g of propylene glycol monomethyl ether acetate (solvent) were prepared to form a homogeneous solution. The solution was then filtered using a polyethylene microfilter with a pore size of 0.10 μm to obtain a positive photosensitive resin composition (solids concentration 32% by mass).

[0090] The contents of components (B) to (E) relative to the positive photosensitive resin compositions of Examples 1 to 6, and when 100 parts by mass of component (A), are shown in Table 1.

[0091] [Graphicality Evaluation] The positive photosensitive resin compositions prepared in Examples 1 to 6 and Comparative Examples 1 and 2 were coated onto silicon wafers using a spin coater and pre-baked at 80°C for 90 seconds on a heated plate to form resin films with the film thicknesses described in Table 2. Next, the resin films were subjected to a first exposure using an i-line stepper (NSR-2205i12D, NA=0.63, manufactured by Nikon) with a specific mask and the exposure amounts described in Table 2. Here, for the 4 μm thick resin films (Examples 1 to 3 and Comparative Examples 1 and 2), a mask with a 4 μm × 4 μm square dot pattern and a 4 μm spacing was used; or for the 1 μm thick resin films (Examples 4 to 6), a mask with a 1 μm × 1 μm square dot pattern and a 1 μm spacing was used. Then, within 10 minutes of the first exposure, development was performed using a 2.38% (w / w) tetramethylammonium hydroxide (TMAH) aqueous solution. For a resin film with a thickness of 4 μm, a 4 μm × 4 μm square dot pattern was formed; for a resin film with a thickness of 1 μm, a 1 μm × 1 μm square dot pattern was formed. The formed square dot patterns were observed using a scanning electron microscope at 5000x magnification. When the distance between adjacent square dot patterns clearly revealed the residue of the aforementioned resin film, the pattern identification evaluation was “×”; when the residue of the aforementioned resin film could not be identified, the pattern identification evaluation was “○”. The evaluation results are shown in Table 2.

[0092]

[0093] [Lens Shape Evaluation] Using the positive photosensitive resin compositions prepared in Examples 1 to 6 and Comparative Examples 1 and 2, and following the order described in the [Patterning Evaluation] section above, square dot patterns of 4 μm × 4 μm were formed on a silicon wafer for a resin film with a film thickness of 4 μm, and square dot patterns of 1 μm × 1 μm were formed on a resin film with a film thickness of 1 μm. Next, the aforementioned square dot patterns were baked on a hot plate at the reflow temperature described in Table 2 for 5 minutes. Further, using the aforementioned i-ray stepper, the entire surface of the aforementioned square dot patterns was subjected to a second exposure at 500 mJ / cm², followed by baking on a hot plate at the subsequent baking temperature described in Table 2 for 10 minutes to fabricate microlenses. Furthermore, for the 1μm × 1μm square dot pattern formed using the positive photosensitive resin composition prepared in Example 4, without reflow baking (in Table 2, reflow temperature is indicated by "none"), microlenses were fabricated using the aforementioned i-ray stepper at 500 mJ / cm² for a second exposure, followed by baking on a heated plate at the subsequent baking temperature recorded in Table 2 for 10 minutes. Microlenses with shapes of quadrangular prisms or frustums were evaluated as "□", while those with truncated spherical or hemispherical shapes were evaluated as "〇". The evaluation results are shown in Table 2.

[0094] [Drug Tolerance Evaluation] The positive photosensitive resin compositions prepared in Examples 1 to 6 and Comparative Examples 1 and 2 were coated onto silicon wafers using a spin coater. The wafers were then pre-baked at 80°C for 90 seconds on a heated plate to form resin films with the thicknesses described in Table 2. Next, the entire surface of the resin film was exposed using the aforementioned i-ray stepper at 500 mJ / cm², followed by baking on a heated plate at the baking temperature described in Table 2 for 10 minutes to form a hardened film. The silicon wafers with the hardened films were then immersed in propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, cyclohexanone, and a 2.38% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) at 23°C for 5 minutes. The thickness of the hardened films before and after immersion was measured, and the change in film thickness before and after immersion was calculated. For any of the solvents used in the aforementioned impregnation, if the film thickness increases or decreases by more than 10% compared to the film thickness before impregnation, the drug resistance evaluation is "×". For all solvents, if the film thickness increases or decreases by less than 10%, the drug resistance evaluation is "○". The evaluation results are shown in Table 2.

[0095] [Transparency Assessment] The positive photosensitive resin compositions prepared in Examples 1 to 6 and Comparative Examples 1 and 2 were respectively coated on a quartz substrate using a spin coater, and pre-baked on a hot plate at 80 °C for 90 seconds to form a resin film having the film thickness shown in Table 2. Next, the entire surface of the resin film was exposed using the aforementioned i-ray stepper at 500 mJ / cm2, and then baked on a hot plate at the post-baking temperature shown in Table 2 for 10 minutes to form a cured film. The quartz substrate having the cured film formed thereon was measured for the transmittance at a wavelength of 400 nm using an ultraviolet-visible spectrophotometer UV-2550 (manufactured by Shimadzu Corporation). When the transmittance at a wavelength of 400 nm was less than 90%, the transparency was evaluated as "×", and when it was more than 90%, the transparency was evaluated as "○". The evaluation results are shown in Table 2.

[0096] [Long-term reliability evaluation] <HTS test> Using the positive photosensitive resin compositions prepared in Examples 1 to 6, a cured film was formed on a quartz substrate in the order described in the aforementioned [Transparency evaluation]. The quartz substrate having the cured film formed thereon was heated in an oven at 100 °C for 1,000 hours, and then the transmittance at a wavelength of 400 nm was measured using the aforementioned ultraviolet-visible spectrophotometer. When the transmittance at a wavelength of 400 nm increased or decreased by more than 5% compared to the transmittance at a wavelength of 400 nm before heating for 1,000 hours, the evaluation was "×", and when the increase or decrease in transmittance was less than 5%, the evaluation was "○". The evaluation results are shown in Table 2.

[0097] <THS test> Using the positive photosensitive resin compositions prepared in Examples 1 to 6, a cured film was formed on a quartz substrate in the order described in the aforementioned [Transparency evaluation]. The quartz substrate having the cured film formed thereon was stored in a constant temperature and humidity chamber maintained at 85 °C and a relative humidity of 85% for 1,000 hours, and then the transmittance at a wavelength of 400 nm was measured using the aforementioned ultraviolet-visible spectrophotometer. When the transmittance at a wavelength of 400 nm increased or decreased by more than 5% compared to the transmittance at a wavelength of 400 nm before storage for 1,000 hours, the evaluation was "×", and when the increase or decrease in transmittance was less than 5%, the evaluation was "○". The evaluation results are shown in Table 2.

[0098] <Xenon-arc test> Using the positive photosensitive resin compositions prepared in Examples 1 to 6, a hardened film was formed on a quartz substrate in the order described above in the [Transparency Evaluation] section. A cutoff filter (L38, manufactured by Shibuya Optical) was installed on the quartz substrate with the hardened film, and the substrate was exposed to 25 million [lx·h] in a xenon arc testing machine (Q-SUN Xe-1, manufactured by Q-Lab). The transmittance at a wavelength of 400 nm was measured using the aforementioned UV-Vis spectrophotometer. A transmittance increase or decrease of 5% or more at 400 nm before exposure in the aforementioned xenon arc testing machine was evaluated as “×”, and a transmittance increase or decrease of less than 5% was evaluated as “○”.

[0099] The results in Table 2 show that by using the positive photosensitive resin composition of the present invention, residue-free and positively patterned microlenses can be formed even in low-temperature processes below 130°C. These microlenses exhibit excellent transparency, drug resistance and long-term reliability.

Claims

1. A positive photosensitive resin composition comprising the following components (A), (B), (C) and solvent: (A) a copolymer of (a1) a monomer represented by formula (1), (a2) a monomer containing an epoxy ring, and (a3) ​​a copolymer of a monomer containing a hydroxyl group with an acid dissociation constant pKa of 14 or more, and a copolymer without carboxyl and carboxylic anhydride groups; (B) a quinone diazide compound; and (C) a photoacid generator (where R0 represents a hydrogen atom or a methyl group, R1 represents a single bond or an alkyl group with 1 or 2 carbon atoms, R2 represents a methyl group, a represents 1 or 2, and b represents an integer from 0 to 2).

2. The positive photosensitive resin composition of claim 1, wherein the monomer containing an epoxy ring in (a2) is a monomer represented by formula (2) below, and the monomer containing a hydroxyl group in (a3) ​​with an acid dissociation constant pKa of 14 or above is a monomer represented by formula (3) below, (wherein, R0 independently represents a hydrogen atom or a methyl group, R3 represents a divalent organic group represented by formula (I) below, R4 represents a monovalent organic group represented by formula (4) or formula (5) below, and R5 represents a monovalent organic group represented by formula (I') below) (wherein, c represents an integer from 0 to 3, d represents an integer from 1 to 3, e independently represents an integer from 2 to 6, * represents a bond with the alkenyl group of the monomer represented by formula (2) or formula (3) below, and ・ represents a bond with the monovalent organic group represented by formula (4) or formula (5) below).

3. The positive photosensitive resin composition of claim 1, wherein the aforementioned component (A) is a copolymer having structural units represented by the following formula (1a), structural units represented by the following formula (2a) and structural units represented by the following formula (3a), (wherein, R0 independently represents a hydrogen atom or a methyl group, R1 represents a single bond or an alkyl group having 1 or 2 carbon atoms, R2 represents a methyl group, b represents an integer from 0 to 2, R4 represents a monovalent organic group represented by the following formula (4) or the following formula (5), and e represents an integer from 2 to 6).

4. A positive photosensitive resin composition of any one of claims 1 to 3, wherein the polystyrene of the aforementioned component (A) has a weight-average molecular weight of 5,000 to 30,000.

5. The positive photosensitive resin composition of any one of claims 1 to 3, wherein the aforementioned component (C) is a nonionic photoacid generator.

6. The positive photosensitive resin composition of claim 5, wherein the aforementioned nonionic photoacid generator is a photoacid generator represented by the following formula (6), (where R6 represents a hydrocarbon group or perfluoroalkyl group having 1 to 10 carbon atoms, and R7 represents a straight-chain alkyl or alkoxy group having 1 to 8 carbon atoms, or a branched alkyl or alkoxy group having 3 to 8 carbon atoms).

7. The positive photosensitive resin composition of any one of claims 1 to 3, further comprising the following component (D): (D) component: a multifunctional epoxy compound.

8. The positive photosensitive resin composition of any one of claims 1 to 3, further comprising the following component (E): sensitizer.

9. The positive photosensitive resin composition of any one of claims 1 to 3 is used for making microlenses.

10. A hardened film obtained from a positive photosensitive resin composition as claimed in any one of claims 1 to 9.

11. A microlens made from a positive photosensitive resin composition as claimed in any one of claims 1 to 9.

12. A method for manufacturing a microlens, comprising the following steps: a coating step of coating a positive photosensitive resin composition as claimed in any one of claims 1 to 9 onto a substrate to form a resin film; a first exposure step of exposing at least a portion of the resin film after the coating step; a development step of removing the exposed portion of the resin film by means of a developer after the first exposure step to form a pattern of the unexposed portion of the resin film; a second exposure step of further exposing the pattern after the development step; and a post-baking step of heating the pattern at a temperature of 130°C or below after the second exposure step.

13. The method for manufacturing a microlens as claimed in claim 12, wherein after the aforementioned development step and before the aforementioned second exposure step, a reflow step is performed in which the aforementioned pattern is heated at a temperature of 130°C or below.

14. A method for manufacturing a microlens as claimed in claim 12 or claim 13, wherein the aforementioned substrate is a substrate on which a color filter is formed.

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