Photocurable composition and photoresist

Abstract

The present invention provides a photocurable composition and a photoresist. The photocurable composition includes resin A, resin B and a crosslinking agent; wherein, resin A is a resin containing epoxy groups; resin B is an acrylate polymer containing a furfuryl ester structure shown by the formula. On the basis of the existing photoresist formulation, the present invention additionally adds an acrylate polymer containing the above-mentioned furfuryl ester structure as the second resin, which can more effectively make up for the deficiencies of the existing photoresist resin, such as poor development effect and bottom undercut, when preparing a cured film with a relatively large thickness. In addition, the addition of resin B in the present invention does not affect other properties of the photoresist, and the application effect is better.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing, and more particularly, to a photocurable composition and a photoresist. Background Art

[0002] In the field of semiconductor manufacturing, photoresists are required in the chip manufacturing processes such as LCD (Liquid Crystal Display), BUMP bumps, MEMS (Micro-Electro-Mechanical System), and 3D-NAND memory. These photoresists are subjected to operations such as coating, pattern exposure, and development to form delicate patterns, and then related microfabrication operations are carried out to form electronic devices with specific structures.

[0003] Currently, in many photoresist forming and processing methods, the thickness of the photoresist coating is generally required to be more than 30 microns. At the same time, the requirements for its appearance, adhesion effect, and mechanical strength are also relatively high. As a common negative photoresist, SU-8 photoresist, firstly, it can form thick film patterns with vertical sidewalls and high aspect ratios. Secondly, it has excellent properties such as good mechanical properties, chemical corrosion resistance, and thermal stability. Thirdly, it can form patterns with complex structures such as steps and has a wide range of applications. However, as the film thickness increases, it becomes difficult for the photoresist to be completely cured. Especially at the bottom of the photoresist film closest to the substrate, it is more likely to have insufficient curing than the top of the film, resulting in problems such as severe undercutting at the bottom during the photoresist development process, which in turn affects the subsequent process operations, leading to easy cracking of the photoresist film, poor development effect, and low yield. At the same time, the above-mentioned photoresist is also prone to problems such as cracking and wire breakage during the curing process of the photoresist film, which in turn affects its application.

[0004] In view of the problems such as cracking of the photoresist film and incomplete curing existing in the application process of the above-mentioned SU8 photoresist, many attempts have been made. For example, US Patent No. 6210862 proposes adding a polymeric resin diluent to the relevant formulation to improve the cracking problem after the photoresist is cured. US Patent No. 5102772 proposes adding a small molecule diluent such as CY179 to the formulation to improve the crosslinking property of the coating film, increase the toughness of the photoresist film, and thus improve its cracking.

[0005] However, although the above patents have improved the problems such as cracking of the SU8 photoresist film to a certain extent, they have not provided solutions to the problems such as undercutting at the bottom of the thick photoresist film and poor development effect. Therefore, it is necessary to provide a photoresist to improve the above problems. Summary of the Invention

[0006] The main object of the present invention is to provide a photocurable composition and a photoresist to solve the problems such as undercutting at the bottom of the thick photoresist film and poor development effect in the prior art.

[0007] To achieve the above object, according to one aspect of the present invention, a photocurable composition is provided. The photocurable composition includes resin A, resin B and a crosslinking agent; wherein, resin A is a resin containing an epoxy group; resin B is an acrylate polymer containing a furfuryl ester structure shown in Formula I; in Formula I, R 9 represents hydrogen, a substituted or unsubstituted C 1 -C 20 alkyl group; R 8 represents hydrogen, a substituted or unsubstituted C 1 -C 20 alkyl group, and x represents an integer from 1 to 20.

[0008]

[0009] Furthermore, by weight, the photocurable composition includes 20 to 60 parts of resin A, 5 to 10 parts of resin B and 1 to 10 parts of the crosslinking agent.

[0010] Furthermore, x represents an integer from 3 to 10, preferably R 8 represents hydrogen or methyl, and R 9 represents hydrogen or methyl; preferably, resin B is formed by copolymerization of an active monomer containing a polymerizable double bond and a furfuryl acrylate monomer; preferably, the active monomer is one or more of styrene, vinyltoluene, α-methylstyrene, p-methylstyrene, p-ethylstyrene, p-chlorostyrene, (meth)acrylic acid, α-bromo(meth)acrylic acid, α-chloro(meth)acrylic acid, β-furyl(meth)acrylic acid, β-styryl(meth)acrylic acid, (meth)acrylic acid alkyl ester, (meth)acrylic acid benzyl ester, phenoxyethyl methacrylate, (meth)acrylic acid tetrahydrofurfuryl ester, (meth)acrylic acid dimethylaminoethyl ester, (meth)acrylic acid diethylaminoethyl ester, (meth)acrylic acid glycidyl ester, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate or 2-ethylhexyl (meth)acrylate.

[0011] Furthermore, the furfuryl acrylate monomer is one or more of methyl furfuryl acrylate, furfuryl acrylate or 2-ethyl furfuryl acrylate.

[0012] Furthermore, the weight average molecular weight of resin B is 6000 to 40000, preferably 8000 to 30000.

[0013] Furthermore, the acid value of resin B is 50 to 200 mgKOH / g, preferably 50 to 100 mgKOH / g.

[0014] Furthermore, the crosslinking agent has a structure shown in General Formula II, or is a compound having any one of Formulas A1 to A12:

[0015]

[0016] Among them, R represents a substituted or unsubstituted C 2 ~C 20 alkyl, cycloalkyl, C 2 ~C 30 alkoxy, substituted or unsubstituted C 6 ~C 30 aryl, or R is a heterocycloalkyl in which carbon atoms are substituted by N, O, S heteroatoms; a represents an integer from 0 to 30, and b represents an integer from 1 to 30;

[0017]

[0018]

[0019] Furthermore, the crosslinking agent of general formula II is a compound having formula A13 or A14, wherein the structures of formula A13 and A14 are:

[0020]

[0021]

[0022] Furthermore, the crosslinking agent is a compound having formula A2, A3, A4, A5, A8, A12 or A13.

[0023] Furthermore, the photocurable composition further comprises a photoinitiator, and the photoinitiator is selected from one or more of iodonium salts, sulfonium salts or arylferrocene salts; preferably, the photoinitiator is a compound having the structure shown in formula III and / or formula IV:

[0024]

[0025] Among them, R 1 and R 2 each independently represent -H, C 1 ~C 20 linear or branched alkyl, C 4 ~C 20 cycloalkylalkyl or alkylcycloalkyl, and the non-cyclic -CH 2 - in these groups may optionally be substituted by -O-, -S- or 1,4-phenylene; R 3 and R 4 each independently represent -H, C 1 ~C 20 linear or branched alkyl, C 4 ~C 20 cycloalkylalkyl or alkylcycloalkyl, C 6 ~C 20Substituted or unsubstituted aryl, and the acyclic -CH in these groups 2 - may be optionally substituted by -O-, -S- or 1,4-phenylene; R 5 represents C 6 ~C 20 Substituted or unsubstituted aryl, C 6 ~C 20 Substituted or unsubstituted alkylaryl, C 1 ~C 20 Straight-chain or branched-chain alkyl, C 4 ~C 20 Cycloalkylalkyl or alkylcycloalkyl, substituted or unsubstituted phenylthiophenyl, and the acyclic -CH in these groups 2 - may be optionally substituted by carbonyl, -O-, -S- or 1,4-phenylene; R 6 and R 7 each independently represents alkyl, hydroxy, alkoxy, alkylcarbonyl, arylcarbonyl, alkoxycarbonyl, aryloxycarbonyl, arylthiocarbonyl, acyloxy, arylthio, aryl, heterocyclic hydrocarbon group, aryloxy, alkylsulfinyl, arylsulfinyl, alkylsulfonyl, arylsulfonyl, hydroxy(poly)alkyleneoxy, substitutable amino, cyano, nitro or halogen atom; m 1 , m 2 respectively represent the number of R 6 and R 7 , selected from 0, 1, 2, 3 or 4; X - represents M - , ClO 4 - , CN - , HSO 4 - , NO 3 - , CF 3 COO - , (BM 4 ) - , (SbM 6 ) - , (AsM 6 ) - , (PM 6 ) - , Al[OC(CF 3 ) 3 4 - , sulfonate ion, B(C 6 M 5 ) 4 - or [(Rf) b PF 6-b ) - ​, where M is a halogen, Rf represents an alkyl group in which ≥80% of the hydrogen atoms are replaced by fluorine atoms, and b represents an integer from 1 to 5.

[0026] Furthermore, resin A is a bisphenol-based epoxy resin, preferably bisphenol A epoxy resin, bisphenol S epoxy resin or bisphenol fluorene epoxy resin, more preferably bisphenol A epoxy resin.

[0027] Furthermore, the photocurable composition further includes a colorant, an additive and a solvent; preferably, the additive includes one or more of a leveling agent, a wetting agent, an adhesion promoter or an ultraviolet absorber; preferably, the colorant is malachite green, methyl violet or methylene blue; preferably, the solvent is one or more of methanol, ethanol, isopropanol, acetone, butanone, 2-pentanone, toluene, ethylbenzene or propylene glycol methyl ether.

[0028] To achieve the above object, according to one aspect of the present invention, a photoresist prepared from the above photocurable composition is provided.

[0029] Based on the existing photoresist formulation, the present invention additionally adds an acrylate polymer containing the above furfuryl ester structure as the second resin (resin B of the present invention), which can more effectively make up for the deficiencies of existing photoresist resins, such as high brittleness and easy cracking when preparing a cured film with a large thickness. At the same time, the double bond activity of resin B of the present invention is better, which can more effectively achieve deep curing, thus significantly avoiding the problem of incomplete bottom curing during the curing process of the photoresist film, greatly reducing the bottom undercut phenomenon during the development process, and then significantly improving the development effect of the photoresist and the yield of subsequent process products. The introduction of the furfuryl ester structure can effectively improve the photocuring activity of the photoresist, making the curing rate faster, the adhesion higher, and improving the development effect. In addition, the addition of resin B of the present invention does not affect other properties of the photoresist (such as leveling property, storage stability, etching resistance, etc.), and the application effect is better. Detailed Embodiments

[0030] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the embodiments.

[0031] As described in the background art section, there are problems such as bottom undercut of the thick photoresist film and poor development effect in the prior art. To solve this problem, the present invention proposes a photocurable composition, which includes resin A, resin B and a crosslinking agent; where resin A is a resin containing an epoxy group; resin B is an acrylate polymer containing a furfuryl ester structure shown in formula I, in formula I, R 9 represents hydrogen, a substituted or unsubstituted C 1 -C 20 alkyl group; R 8represents hydrogen, substituted or unsubstituted C 1 ~C 20 alkyl, and x represents an integer from 1 to 20.

[0032]

[0033] Based on the existing photoresist formulation, the present invention additionally adds an acrylate polymer containing the above-mentioned furfuryl ester structure as the second resin (resin B of the present invention), which can more effectively compensate for the deficiencies of existing photoresist resins, such as high brittleness and easy cracking when preparing a cured film with a relatively large thickness. At the same time, the double bonds of resin B of the present invention have good activity, which can more effectively achieve deep curing, thus significantly avoiding the problem of incomplete bottom curing during the curing process of the photoresist film, greatly reducing the bottom undercut phenomenon during the development process, and then significantly improving the development effect of the photoresist and the yield of products in subsequent processes. The introduction of the furfuryl ester structure can effectively improve the photocuring activity of the photoresist, resulting in a faster curing rate, high adhesion, and improved development effect. In addition, the addition of resin B of the present invention does not affect other properties of the photoresist (such as leveling property, storage stability, etching resistance, etc.), and the application effect is better.

[0034] In order to further avoid the problem of incomplete bottom curing during the curing process of the photoresist film, and then significantly improve the development effect of the photoresist and the yield of products in subsequent processes, preferably, the photocurable composition comprises 20 - 60 parts by weight of resin A, 5 - 10 parts by weight of resin B, and 1 - 10 parts by weight of a crosslinking agent. Based on this, the synergistic effect among the above components is better. While significantly improving the deep curing and development effect of the photoresist, other properties of the photoresist (such as leveling property, storage stability, etching resistance, etc.) also meet the actual use requirements.

[0035] Preferably, x represents an integer from 3 to 10; R 8 represents hydrogen or methyl, and R 9 represents hydrogen or methyl. Preferably, resin B is formed by copolymerization of an active monomer containing a polymerizable double bond and a furfuryl acrylate monomer, and resin B is formed by copolymerization of an active monomer containing a polymerizable double bond and a furfuryl acrylate monomer through a copolymerization reaction.

[0036] Preferably, the active monomer is one or more of styrene, vinyltoluene, α-methylstyrene, p-methylstyrene, p-ethylstyrene, p-chlorostyrene, (meth)acrylic acid, α-bromo(meth)acrylic acid, α-chloro(meth)acrylic acid, β-furyl(meth)acrylic acid, β-styryl(meth)acrylic acid, alkyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl methacrylate, tetrahydrofurfuryl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, glycidyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate or 2-ethylhexyl (meth)acrylate. Preferably, the furfuryl acrylate monomer is one or more of furfuryl methacrylate, furfuryl acrylate or 2-ethylfurfuryl acrylate.

[0037] In a preferred embodiment, under the condition of maintaining a nitrogen atmosphere, the active monomer containing a polymerizable double bond and the furfuryl acrylate monomer are placed in a reaction kettle and mixed. The initiator solution is respectively placed in a constant pressure funnel and simultaneously added dropwise to the reaction system for copolymerization reaction to obtain the resin B of the present invention. Preferably, by weight, the furfuryl acrylate monomer accounts for 5-20 wt% of the above mixture.

[0038] For the purpose of balancing the development time of the photoresist and the pattern application effect, the weight average molecular weight of the resin B is preferably 6000-40000. When the weight average molecular weight of the resin B is greater than 40000, due to the relatively large molecular weight, the development time will be significantly prolonged and the smoothness of the pattern appearance will be significantly decreased. When the weight average molecular weight of the resin B is less than 6000, it will affect the adhesion of the pattern to the substrate and the problem of peeling is likely to occur. The weight average molecular weight of the resin B is preferably 8000-30000, more preferably 8000-20000. The weight average molecular weight is measured by gel permeation chromatography (GPC) and obtained by conversion using the standard curve of standard polystyrene.

[0039] For the purpose of further improving the developability of the photoresist and the stability of the composition, the acid value of the resin B is preferably 50-200 mgKOH / g, more preferably 50-100 mgKOH / g.

[0040] In order to further improve the problems such as thick film cracking and insufficient toughness of the existing photoresist, and at the same time considering the better synergistic effect with the resin B provided by the present invention, the crosslinking agent preferably has the structure shown in General Formula II, or is a compound having any one of Formulas A1 to A12:

[0041]

[0042] Among them, R represents substituted or unsubstituted C 2 ~C20 Alkyl, cycloalkyl, C 2 ~C 30 Alkoxy, substituted or unsubstituted C 6 ~C 30 Aryl; alternatively, R is a heterocycloalkyl in which a carbon atom is substituted by N, O, S heteroatoms; a represents an integer from 0 to 30, and b represents an integer from 1 to 30;

[0043]

[0044]

[0045] The crosslinking agent is selected from substances having the above structures, and can cooperate with the resin to further effectively make up for the deficiencies of existing photoresists, such as high brittleness and easy cracking when preparing a cured film with a relatively large thickness, thereby more effectively improving the toughness and adhesion of the cured film and significantly improving the application effect of the photoresist. For the above crosslinking agent general formula compound, the preparation method of Chinese Patent CN110713561A can be referred to, and a compound containing a hydroxyl group or other active groups can be prepared, and then the hydroxyl group, epoxy and other active functional groups connected by the oxetane side chain are used to achieve grafting, thereby preparing a compound containing multiple epoxy groups, that is, the above crosslinking agent, which can be realized by those skilled in the art themselves and will not be elaborated here.

[0046] Preferably, the crosslinking agent of general formula II is a compound having formula A13 or A14, wherein the structures of formula A13 and A14 are:

[0047]

[0048] More preferably, the crosslinking agent of general formula II is a compound having formula A2, A3, A4, A5, A8, A12 or A13. Based on this, the crosslinking agents with these structures can endow the thick film photoresist with a higher crosslinking density and better toughness, thereby further effectively improving problems such as cracking and bottom undercut of the thick film.

[0049] In a preferred embodiment, the photocurable composition further includes a photoinitiator, and the photoinitiator can be selected from conventional photoinitiators in the art. As long as the photoinitiator can generate a strong acid under light irradiation and can smoothly open the epoxy ring to achieve crosslinking and curing of the composition. In order to obtain a better cured film, it is preferred that the photoinitiator in the composition of the present invention is selected from one or more of iodonium salts, sulfonium salts or arylferrocene salts; more preferably, the photoinitiator is a compound having the structure shown in formula III and / or formula IV:

[0050]

[0051] Wherein, R 1 and R2 each independently represents -H, C 1 ~C 20 linear or branched alkyl, C 4 ~C 20 cycloalkylalkyl or alkylcycloalkyl, and the acyclic -CH 2 - in these groups may optionally be substituted by -O-, -S- or 1,4-phenylene; R 3 and R 4 each independently represents -H, C 1 ~C 20 linear or branched alkyl, C 4 ~C 20 cycloalkylalkyl or alkylcycloalkyl, C 6 ~C 20 substituted or unsubstituted aryl, and the acyclic -CH 2 - in these groups may optionally be substituted by -O-, -S- or 1,4-phenylene; R 5 represents C 6 ~C 20 substituted or unsubstituted aryl, C 6 ~C 20 substituted or unsubstituted alkylaryl, C 1 ~C 20 linear or branched alkyl, C 4 ~C 20 cycloalkylalkyl or alkylcycloalkyl, substituted or unsubstituted phenylthiophenyl, and the acyclic -CH 2 - in these groups may optionally be substituted by carbonyl, -O-, -S- or 1,4-phenylene; R 6 and R 7 each independently represents alkyl, hydroxy, alkoxy, alkylcarbonyl, arylcarbonyl, alkoxycarbonyl, aryloxycarbonyl, arylthiocarbonyl, acyloxy, arylthio, aryl, heterocyclic hydrocarbon group, aryloxy, alkylsulfinyl, arylsulfinyl, alkylsulfonyl, arylsulfonyl, hydroxy(poly)alkyleneoxy, substitutable amino, cyano, nitro or halogen atom; m 1 、m 2 respectively represent the number of R 6 and R 7 selected from 0, 1, 2, 3 or 4; X - represents M - 、ClO 4 - 、CN - 、HSO 4 - 、NO 3 - 、CF 3 COO - 、(BM4 ) - 、(SbM 6 ) - 、(AsM 6 ) - 、(PM 6 ) - 、Al[OC(CF 3 ) 3 4 - 、sulfonate ion, B(C 6 M 5 ) 4 - or [(Rf) b PF 6-b - , wherein M is a halogen, Rf represents an alkyl group in which ≥80% of the hydrogen atoms are replaced by fluorine atoms, and b represents an integer from 1 to 5.

[0052] More preferably, in the compounds of the structures shown in Formula III and Formula IV: R 1 and R 2 each independently represent hydrogen, a straight-chain or branched-chain alkyl group of C 1 to C 12 , a cycloalkylalkyl group or an alkylcycloalkyl group of C 4 to C 10 , and the non-cyclic -CH 2 - in these groups may optionally be replaced by -O-; R 3 and R 4 each independently represent hydrogen, a straight-chain or branched-chain alkyl group of C 1 to C 10 , a cycloalkylalkyl group or an alkylcycloalkyl group of C 4 to C 10 , a substituted or unsubstituted aryl group of C 6 to C 12 , and the non-cyclic -CH 2 - in these groups may optionally be replaced by -O-, -S- or 1,4-phenylene; R 5 represents a substituted or unsubstituted aryl group of C 6 to C 10 , a substituted or unsubstituted alkylaryl group of C 6 to C 10 , a substituted or unsubstituted phenylthiophenyl group, and the non-cyclic -CH 2 - in these groups may optionally be replaced by a carbonyl group, -O-, -S- or 1,4-phenylene; R 6 and R 7 represent a straight-chain or branched-chain alkyl group of C 1 to C 10 , a cycloalkylalkyl group or an alkylcycloalkyl group of C 1 to C​​10 linear or branched alkoxy groups, C 1 ~C 10 alkyl carbonyl groups and halogens having ~ carbon atoms.

[0053] It should be noted that commercially available cationic photoinitiators having the above similar structures can also be used in the present invention, including but not limited to PAG20001, PAG20001s, PAG20002, PAG20002s, PAG30201, PAG30101, etc. produced by Tronly Company, and Irgacure250 produced by BASF Company, etc.

[0054] Preferably, resin A is a bisphenol-based epoxy resin, preferably bisphenol A epoxy resin, bisphenol S epoxy resin or bisphenol fluorene epoxy resin, and more preferably bisphenol A epoxy resin. Commercially available SU8 epoxy resin can be selected as the bisphenol A epoxy resin. The selection of the above resin A can be made according to the resin types in conventional photoresists in the art, which can be selected by those skilled in the art according to their own needs when facing the present invention, and will not be elaborated here.

[0055] Preferably, the photocurable composition further comprises a colorant, an additive and a solvent. The additive includes one or more of a leveling agent, a wetting agent, an adhesion promoter or an ultraviolet absorber. Among them, commercially available surfactants can be used as the leveling agent, specifically including silicone surfactants, ester surfactants, ionic surfactants, non-ionic surfactants, amphoteric surfactants, etc. These surfactants can be used alone or in combination of two or more. Silane compounds can be used as the adhesion promoter, and specifically, examples include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, etc. The above adhesion promoters can be used alone or in combination of two or more. Antioxidants specifically include, for example, 4,4'-butylidenebis(6-tert-butyl-3-methylphenol), 2,6-di-tert-butyl-4-methylphenol, 2,3'-thiobis(4-methyl-6-tert-butylphenol), p-methoxyphenol, etc. 2-(3-tert-butyl-2-hydroxy-5-methylphenyl)-5-chlorobenzotriazole and alkoxydibenzophenone, etc. can be selected as the ultraviolet absorber.

[0056] It should be noted that there is no particular limitation on the colorant, and those skilled in the art can make an independent choice according to their own usage requirements, and will not be elaborated here. The colorant can be malachite green, methyl violet or methylene blue. The solvent is used to fully disperse the resin, filler and other components.

[0057] The solvent can play a dispersing role and can be quickly dried at a specific temperature. Preferably, the solvent is one or more of methanol, ethanol, isopropanol, acetone, butanone, 2-pentanone, toluene, ethylbenzene or propylene glycol methyl ether. The solvent is selected from the above types, which has a better dispersing effect on the resin and additives of the present invention and can be quickly dried at a relatively low temperature.

[0058] In a preferred embodiment, the photocurable composition of the present invention further comprises, by weight, 1 to 6 parts of a photoinitiator, 5 to 20 parts of a colorant, 0.1 to 3 parts of an auxiliary agent, and 15 to 70 parts of a solvent.

[0059] The invention also provides a photoresist, which is prepared from the photocurable composition.

[0060] Based on the above reasons, the photoresist of the present invention effectively improves the development effect and adhesion of the film, improves the undercut problem of the pattern during the development process, and solves the cracking problem of the film, thereby achieving good application effects.

[0061] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0062] Synthesis of Resin B

[0063] Accurately weigh a certain amount of active monomers containing polymerizable double bonds and (meth) acrylate furfuryl, mix them thoroughly, and cool them to below 10°C for use; in addition, accurately weigh a certain amount of initiator (azobisisobutyronitrile) and dissolve it in 3 times the amount of butanone solvent, and dissolve it thoroughly for use. In a four-necked flask equipped with a stirring device, a condenser, a constant pressure dropping funnel, a thermometer and a nitrogen inlet, add 100g butanone, pass nitrogen, heat to 70°C under sufficient stirring conditions, and drop the monomer mixture and initiator solution respectively. The dropping time is controlled within 2h. After the dropping is completed, keep it warm at this temperature for 4h, measure the weight average molecular weight (Mw) of the system, and then heat it to 80°C. After reflux reaction for 2h, cool it to room temperature and filter the material.

[0064] Resins B1 to B6 were prepared according to different monomers and ratios, wherein B6 was an acrylic ester polymer without furfuryl ester structure. The synthetic formula is shown in Table 1.

[0065] Table 1

[0066] Raw materials B1 B2 B3 B4 B5 B6 Methacrylic acid / g 10 10 10 10 10 10 Methyl methacrylate / g 30 30 30 30 30 40 Benzyl methacrylate / g 20 20 20 20 20 20 Dicyclopentanyl methacrylate / g 15 10 10 5 0 10 Styrene / g 20 20 16 20 20 20 Furfuryl methacrylate 5 10 14 15 20 0 Azobisisobutyronitrile / g 4 5 5 3 3 4 Mw 10783 11295 10733 11113 10030 10212

[0067] The photocurable compositions of Examples 1 to 12 and Comparative Examples 1 to 5 were prepared according to the following formula:

[0068]

[0069] According to the above formula, add the above components into a reaction kettle, stir well at room temperature. After the sample is completely dissolved, filter it with a polypropylene (PP) microporous membrane with a pore size of 1.2 μm, and then encapsulate it to form a photoresist. The specific component types in the above examples and comparative examples are shown in Table 2 below.

[0070] Table 2

[0071]

[0072]

[0073] In order to further compare the influence of adding Resin B on the application effect of the composition, the following examples are added:

[0074] Example 13

[0075] The difference from Example 4 is only that the weight part of Resin B is 5 parts.

[0076] Example 14

[0077] The difference from Example 4 is only that the weight part of Resin B is 20 parts.

[0078] Example 15

[0079] The difference from Example 4 is only that the weight part of the crosslinking agent is 15 parts.

[0080] Example 16

[0081] The difference from Example 4 is only that the crosslinking agent is diglycol diglycidyl ether.

[0082] Performance characterization:

[0083] Pattern formation method: Coating the photoresists of the above examples and comparative examples on a copper-plated substrate, then drying on a hot plate at 130 °C for 8 minutes, and repeating this method once to obtain a coating with a film thickness of 250 μm. This film coating is exposed with an ELS201SA exposure machine at an energy of 2000 - 3000 mJ / cm 2 . After that, develop it with a 0.25 mol / L aqueous solution of tetramethylammonium hydroxide. Observe the appearance of the obtained pattern through a scanning electron microscope to check whether it is smooth, whether there are cracks; the undercut situation at the bottom; and also check the adhesion of the pattern through the cross-cut test method. The specific evaluation methods and standards are described as follows:

[0084] (I) Development effect:

[0085] The pattern surface is smooth and there are no serrated edges: ○

[0086] The pattern surface is smooth with a small amount of serration at the edges: △

[0087] The pattern surface is rough with many serrations at the edges: ╳

[0088] (2) Undercut at the bottom:

[0089] Small undercut at the bottom: ○

[0090] Medium undercut at the bottom: △

[0091] Large undercut at the bottom: ╳

[0092] (3) Adhesion:

[0093] Cross-cut test method: After the developed pattern is dried, use a cross-cut knife to cut horizontally and vertically ten times every 1 mm on the substrate, conduct a peel test using a standard 3M 600 tape, and observe the remaining amount of the pattern on the substrate using a scanning electron microscope. The more the remaining amount, the better the adhesion. The evaluation criteria are as follows:

[0094] Not peeled off from the substrate, pattern intact: ○

[0095] 1 - 5 squares peeled off from the substrate: △

[0096] More than 5 squares peeled off from the substrate: ╳

[0097] (4) Film cracking situation:

[0098] No cracking: ○

[0099] Cracking: ╳

[0100] The evaluation results of the examples and comparative examples are shown in Table 3 below.

[0101] Table 3

[0102]

[0103]

[0104] From the test data of the above examples and comparative examples, it can be seen that by using resin B with a specific structural general formula of the present invention, the adhesion performance between the photoresist film and the substrate can be effectively improved, deep curing of the thick film photoresist can be achieved, and problems such as undercut at the bottom can be effectively reduced. In particular, when the crosslinking agent is selected from compounds having an ether bond flexible long-chain group, such as Examples 4, 5, 6, and 7 corresponding to A3, A13, A4, and A5, better development effects and adhesion are shown, and there is no cracking phenomenon.

[0105] Under the same development conditions, in Comparative Example 1, only Resin B was added. Although the development and adhesion were improved to some extent, the film cracked and the overall effect was not good. In Comparative Example 2, only polyethylene glycol diglycidyl ether was added as an additive. Although the problem of film cracking was significantly improved, the development effect, adhesion and other properties were inferior to those shown in other embodiments provided by the present invention. In Comparative Example 5, neither Resin B nor a crosslinking agent was added, and problems such as developability, adhesion and film cracking were more obvious. Comparative Example 3 showed that when a resin without a furfuryl ester side chain was combined with a polyfunctional epoxy crosslinking agent, although the development effect and adhesion were improved, the problem of thick film cracking was not improved. In Comparative Example 4, only a crosslinking agent was added, and the development effect was improved to some extent, but the adhesion and undercut problems were not improved. From the above, it can be seen that the use of Resin B and a crosslinking agent in combination in the thick film photoresist greatly improves its development effect and adhesion, improves problems such as undercut of the pattern during development, and at the same time can effectively avoid the problem of thick film cracking, achieving good application effects.

[0106] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A photocurable composition, characterized in that, the photocurable composition comprises 20 - 60 parts of resin A, 5 - 10 parts of resin B and 1 - 10 parts of crosslinking agent; wherein, the resin A is bisphenol A epoxy resin; the resin B is an acrylate polymer containing a furfuryl ester structure shown in formula I; In the formula I, R 9 represents hydrogen, substituted or unsubstituted C 1 ~C 20 alkyl; R 8 represents hydrogen, substituted or unsubstituted C 1 ~C 20 alkyl, and x represents an integer from 1 to 20; the resin B is formed by copolymerization of an active monomer containing a polymerizable double bond and a furfuryl acrylate monomer; based on the weight fraction of the active monomer containing a polymerizable double bond and the furfuryl acrylate monomer being 100%, the weight fraction of the furfuryl acrylate monomer is 5% - 20%; the weight - average molecular weight of the resin B is 6000 - 40000; the acid value of the resin B is 50 - 200 mgKOH / g; the crosslinking agent has a structure shown in general formula II, or is a compound having any one of formulas A2 to A10 and A12: Among them, R represents a substituted or unsubstituted C 2 ~C 20 alkyl, cycloalkyl, C 2 ~C 30 alkoxy, a substituted or unsubstituted C 6 ~C 30 aryl, or R is a heterocycloalkyl in which carbon atoms are substituted by N, O, S heteroatoms; a represents an integer from 0 to 30, and b represents an integer from 1 to 30; the active monomer containing a polymerizable double bond is one or more of styrene, vinyltoluene, p - ethylstyrene, p - chlorostyrene, (meth)acrylic acid, α - bromo - (meth)acrylic acid, α - chloro - (meth)acrylic acid, β - furyl - (meth)acrylic acid, β - styryl - (meth)acrylic acid, (meth)acrylic acid alkyl ester, (meth)acrylic acid benzyl ester, phenoxyethyl methacrylate, (meth)acrylic acid tetrahydrofurfuryl ester, (meth)acrylic acid dimethylaminoethyl ester, (meth)acrylic acid diethylaminoethyl ester, (meth)acrylic acid glycidyl ester, 2,2,2 - trifluoroethyl (meth)acrylate, 2,2,3,3 - tetrafluoropropyl (meth)acrylate, 2 - ethylhexyl (meth)acrylate.

2. The photocurable composition according to claim 1, characterized in that, x represents an integer from 3 to 10.

3. The photocurable composition according to claim 2, characterized in that, The R 8 represents hydrogen or methyl, and the R 9 represents hydrogen or methyl.

4. The photocurable composition according to claim 3, characterized in that, the furfuryl acrylate monomer is one or more of methyl furfuryl acrylate, furfuryl acrylate or 2 - ethyl furfuryl acrylate.

5. The photocurable composition according to any one of claims 1 to 3, characterized in that, the weight - average molecular weight of the resin B is 8000 - 30000.

6. The photocurable composition according to any one of claims 1 to 3, characterized in that, the acid value of the resin B is 50 - 100 mgKOH / g.

7. The photocurable composition according to claim 1, characterized in that, the crosslinking agent of general formula II is a compound having formula A1, A11, A13 or A14, wherein the structures of formula A1, A11, A13 and A14 are:

8. The photocurable composition according to claim 7, characterized in that, the crosslinking agent is a compound having formula A2, A3, A4, A5, A8, A12 or A13.

9. The photocurable composition according to any one of claims 1 to 3, characterized in that, the photocurable composition further comprises a photoinitiator, and the photoinitiator is selected from one or more of iodonium salts, sulfonium salts or arylferrocene salts.

10. The photocurable composition according to claim 9, wherein, the photoinitiator is a compound having the structure shown in formula III and / or formula IV: wherein, R 1 and R 2 each independently represent -H, a linear or branched alkyl group having from C 1 to C 20 atoms, a cycloalkylalkyl or alkylcycloalkyl group having from C 4 to C 20 atoms, and the non-cyclic -CH 2 - in these groups may optionally be replaced by -O-, -S- or 1,4-phenylene; R 3 and R 4 each independently represent -H, a linear or branched alkyl group having from C 1 to C 20 atoms, a cycloalkylalkyl or alkylcycloalkyl group having from C 4 to C 20 atoms, a substituted or unsubstituted aryl group having from C 6 to C 20 atoms, and the non-cyclic -CH 2 - in these groups may optionally be replaced by -O-, -S- or 1,4-phenylene; R 5 represents a substituted or unsubstituted aryl group having from C 6 to C 20 atoms, a substituted or unsubstituted alkylaryl group having from C 6 to C 20 atoms, a linear or branched alkyl group having from C 1 to C 20 atoms, a cycloalkylalkyl or alkylcycloalkyl group having from C 4 to C 20 atoms, a substituted or unsubstituted phenylthiophenyl group, and the non-cyclic -CH 2 - in these groups may optionally be replaced by a carbonyl group, -O-, -S- or 1,4-phenylene; R 6 and R 7 each independently represent an alkyl group, a hydroxyl group, an alkoxy group, an alkylcarbonyl group, an arylcarbonyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an arylthiocarbonyl group, an acyloxy group, an arylthio group, an aryl group, a heterocyclic hydrocarbon group, an aryloxy group, an alkylsulfinyl group, an arylsulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, a hydroxyl(poly)alkyleneoxy group, a substitutable amino group, a cyano group, a nitro group or a halogen atom; m 1 , m 2 respectively represent the number of R 6 and R 7 , and are selected from 0, 1, 2, 3 or 4; X - represents M - , ClO 4 - , CN - , HSO 4 - , NO 3 - , CF 3 COO - 、(BM 4 ) - 、(SbM 6 ) - 、(AsM 6 ) - 、(PM 6 ) - 、Al[OC(CF 3 ) 3 4 - 、 sulfonate ion, B(C 6 M 5 ) 4 - or [(Rf) b PF 6-b - , where M is a halogen, Rf represents an alkyl group in which ≥80% of the hydrogen atoms are replaced by fluorine atoms, and b represents an integer from 1 to 5.​​ 11. The photocurable composition according to any one of claims 1 to 3, wherein, the photocurable composition further comprises a colorant, an auxiliary agent and a solvent.

12. The photocurable composition according to claim 11, wherein, the auxiliary agent includes one or more of a leveling agent, a wetting agent, an adhesion promoter or an ultraviolet absorber; and / or, the colorant is malachite green, methyl violet or methylene blue; and / or, the solvent is one or more of methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, 2-pentanone, toluene, ethylbenzene or propylene glycol methyl ether.

13. A photoresist, wherein, the photoresist is prepared from the photocurable composition according to any one of claims 1 to 12.

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