Photocurable resin composition and use thereof

Abstract

The application provides a photocuring resin composition and application thereof. The photocuring resin composition comprises, in parts by weight, 45-60 parts of alkali-soluble resin, 30-50 parts of polymerized monomer and 2.5-5 parts of photoinitiator; the alkali-soluble resin comprises a mixture of compounds represented by general formula (I), (II) and (III). The inventors reorganize the structure and performance of the alkali-soluble resin, split the originally multifunctional single alkali-soluble resin into several compounds with specific functions, and obtain a photocuring resin composition with excellent comprehensive performance of high adhesion, high resolution, developing dispersion performance and softness by compounding the addition ratio of the above-mentioned compounds with specific functions, and the above-mentioned amount of polymerized monomer and photoinitiator, thereby meeting the PCB production in the field of IC packaging carrier board.

Description

Technical Field

[0001] This invention relates to the field of photoresist material preparation technology, and more specifically, to a photocurable resin composition and its application. Background Technology

[0002] In the manufacturing process of printed circuit boards (PCBs), lead frames (LFs), and semiconductor packaged (IC) substrates, photosensitive resin compositions are widely used as resist materials for etching or electroplating. These are also known as photosensitive dry films or dry film resists. Photosensitive dry films are composed of a PET support film layer, an intermediate photosensitive resist layer, and a PE protective layer. Pattern transfer is achieved through photocuring, and the following methods are used for manufacturing: First, the photosensitive resin composition is pressed onto a copper plate; then, specific areas of the photosensitive resin composition layer are exposed; then, the PET support film is peeled off, and the unexposed areas are removed with a chemical solution; next, the substrate with the resist pattern is etched, and the resist layer is peeled off to form the circuit pattern; or, electroplating is performed, followed by peeling off the resist layer and etching the metal surface covered by the resist layer to form the circuit pattern.

[0003] In recent years, with the continuous trend towards lighter and thinner electronic devices, semiconductor package pin designs such as BGA and CSP have become increasingly smaller and denser, leading to more refined and higher-density circuitry on the carrier boards and PCBs supporting them. In the field of semiconductor packaging carrier boards, especially with the increasingly popular FC-BGA packaging method, the conductor dimensions of the carrier board are generally below 15μm. This necessitates that the photosensitive resin composition can form resist patterns with a resolution of less than 10μm to ensure a sufficient yield.

[0004] On the other hand, the rapid development of 5G communication technology has placed higher demands on PCB-related materials. For example, when using high-frequency, high-speed copper-clad laminate materials and dielectric multilayer materials, it is necessary to fabricate circuits on the surface of very low profile copper foil, or first deposit a smooth, thin copper layer on the surface of the build-up layer using chemical methods, and then use a photocurable resin composition to form circuits on the copper surface through a pattern transfer method (semi-additive SAP process). Forming fine circuits on such smooth copper surfaces with low roughness places higher demands on the adhesion of the photocurable resin composition.

[0005] Alkali-soluble resins are the main component of photocurable resin compositions, significantly influencing the developer dispersion, adhesion, resolution, and stripping performance of these compositions. In the field of dry film production on carrier plates, where high resolution is required, alkali-soluble resins with a high content of benzene-containing copolymer units are commonly used in photocurable resin compositions. These may be copolymers of methacrylic acid / styrene / benzyl methacrylate or methacrylic acid / styrene / cycloalkyl methacrylate. Sometimes, small amounts of auxiliary comonomers such as methyl methacrylate and isooctyl acrylate are added to adjust developer dispersion and stripping performance. However, in practical applications, these alkali-soluble resins still cannot adequately balance adhesion, stripping time, and developer dispersion, resulting in problems such as insufficient stripping performance or insufficient developer dispersion.

[0006] Therefore, it is necessary to research and develop a photocurable resin composition that combines excellent adhesion, film removal time, and developer dispersion properties. Summary of the Invention

[0007] The main objective of this invention is to provide a photocurable resin composition and its application, in order to solve the problem that photocurable resin compositions in the prior art are difficult to have both excellent adhesion, film removal time and developer dispersion performance.

[0008] To achieve the above objectives, the present invention provides a photocurable resin composition, comprising, by weight: 45-60 parts of an alkali-soluble resin, 30-50 parts of a polymeric monomer, and 2.5-5 parts of a photoinitiator; the alkali-soluble resin comprising a mixture of compounds represented by general formulas (I), (II), and (III).

[0009]

[0010] Each R1 and each R2 is independently selected from hydrogen atoms or methyl groups; R' is selected from substituted or unsubstituted alkyl groups of C2 to C8; based on the percentage of the molecular weight of the compound represented by general formula (I), the content of the segment corresponding to x1 is 25-35 wt%, and the content of the segment corresponding to y1 is 65-75 wt%; based on the percentage of the molecular weight of the compound represented by general formula (II), the content of the segment corresponding to x2 is 20-35 wt%, and the content of the segment corresponding to y2 is 65-80 wt%; based on the percentage of the molecular weight of the compound represented by general formula (III), the content of the segment corresponding to x3 is 20-30 wt%, and the content of the segment corresponding to y3 is 70-80 wt%.

[0011] Furthermore, based on the percentage of the molecular weight of the compound represented by general formula (I), the content of the chain segment corresponding to x1 is 27–33 wt%, and the content of the chain segment corresponding to y1 is 67–73 wt%; based on the percentage of the molecular weight of the compound represented by general formula (II), the content of the chain segment corresponding to x2 is 25–33 wt%, and the content of the chain segment corresponding to y2 is 67–75 wt%; based on the percentage of the molecular weight of the compound represented by general formula (III), the content of the chain segment corresponding to x3 is 23–28 wt%, and the content of the chain segment corresponding to y3 is 72–77 wt%.

[0012] Furthermore, the weight ratio of the compound shown in general formula (I), the compound shown in general formula (II), and the compound shown in general formula (III) is (20-45):(10-25):(4-9).

[0013] Further, in the compound represented by general formula (III), when all R's are C2-C4 substituted or unsubstituted alkyl groups, the content of the segment corresponding to x3 is 20-30 wt% and the content of the segment corresponding to y3 is 70-80 wt% based on the percentage of the molecular weight of the compound represented by general formula (III); in the compound represented by general formula (III), when some R's are C2-C4 substituted or unsubstituted alkyl groups and another part of R's are C5-C8 substituted or unsubstituted alkyl groups, the content of the segment corresponding to x3 is 20-30 wt% and the content of the segment corresponding to y3 is 70-80 wt% based on the percentage of the molecular weight of the compound represented by general formula (III). The content of the corresponding chain segment 3 is 22-30 wt%, and the content of the corresponding chain segment y3 is 70-78 wt%. Preferably, the weight ratio of substituted or unsubstituted alkyl groups of C2-C4 to substituted or unsubstituted alkyl groups of C5-C8 is (50-80):(20-50). In the compound shown in general formula (III), when all R' are substituted or unsubstituted alkyl groups of C5-C8, the content of the corresponding chain segment x3 is 24-30 wt%, and the content of the corresponding chain segment y3 is 70-76 wt%, based on the percentage of the molecular weight of the compound shown in general formula (III).

[0014] Further, in the compound of general formula (III), when all R's are butyl, the content of the chain segment corresponding to x3 is 20-30 wt% and the content of the chain segment corresponding to y3 is 70-80 wt% based on the percentage of the molecular weight of the compound of general formula (III); in the compound of general formula (III), when some R's are isooctyl and the other part of R's are butyl, the content of the chain segment corresponding to x3 is 22-30 wt% and the content of the chain segment corresponding to y3 is 70-78 wt% based on the percentage of the molecular weight of the compound of general formula (III); preferably, the weight ratio of isooctyl to butyl is (20-50):(50-80); in the compound of general formula (III), when all R's are isooctyl, the content of the chain segment corresponding to x3 is 24-30 wt% and the content of the chain segment corresponding to y3 is 70-76 wt% based on the percentage of the molecular weight of the compound of general formula (III).

[0015] Furthermore, the compounds represented by general formula (I) have a weight-average molecular weight of 25,000–60,000, an acid value of 160–230 mg KOH / g, and a molecular weight distribution index of 1.0–3.0; the compounds represented by general formula (II) have a weight-average molecular weight of 25,000–60,000, an acid value of 130–230 mg KOH / g, and a molecular weight distribution index of 1.0–3.0; the compounds represented by general formula (III) have a weight-average molecular weight of 25,000–60,000, an acid value of 130–200 mg KOH / g, and a molecular weight distribution index of 1.0–3.0.

[0016] Further, the polymerization monomer is an olefinically unsaturated double-bonded monomer; preferably, the polymerization monomer is selected from one or more of the group consisting of ethoxylated nonylphenol acrylate monomers, ethoxylated bisphenol A di(meth)acrylate monomers, polyethylene glycol di(meth)acrylate monomers, trimethylolpropane tri(meth)acrylate monomers, and ethoxylated trimethylolpropane tri(meth)acrylate monomers; more preferably, the polymerization monomer is selected from ethoxylated bisphenol A di(meth)acrylate monomers; more preferably, it is 4-ethoxylated bisphenol A di(meth)acrylate and / or 10-ethoxylated bisphenol A di(meth)acrylate; or, more preferably, the polymerization monomer is selected from a mixture of ethoxylated bisphenol A di(meth)acrylate monomers and ethoxylated trimethylolpropane tri(meth)acrylate monomers.

[0017] Further, the photoinitiator is selected from one or more of the group consisting of 2-(o-chlorophenyl)-4,5-diphenylimidazolium dimer, 2-(o-chlorophenyl)-4,5-di(methoxyphenyl)imidazolium dimer, 2-(o-fluorophenyl)-4,5-diphenylimidazolium dimer, 2-(o-methoxyphenyl)-4,5-diphenylimidazolium dimer, 2-(p-methoxyphenyl)-4,5-diphenylimidazolium dimer, and 2,2',4-tris(2-chlorophenyl)-5-(3,4-dimethoxyphenyl)-4',5'-diphenyl-1,1'-diimidazole; preferably, it is used to initiate light... The photocurable resin composition further includes, by weight percentage of the initiator, 3-30 wt% of a sensitizer; more preferably, the sensitizer is selected from one or more of the group consisting of benzophenone compounds, pyrazoline compounds, acridine compounds, coumarin compounds, and anthracene compounds; even more preferably, it is selected from one or more of the group consisting of benzophenone, N,N'-tetramethyl-4,4'-diaminobenzophenone, N,N'-tetraethyl-4,4'-diaminobenzophenone, 4-methoxy-4'-dimethylaminobenzophenone, and N-phenylglycine; even more preferably, it is benzophenone.

[0018] Further, by weight, the photocurable resin composition further includes: 0.5 to 5.0 parts of additives; preferably, the additives are selected from one or more of dyes, colorants, plasticizers, defoamers, leveling agents, adhesion promoters and polymerization inhibitors.

[0019] To achieve the above objectives, another aspect of the present invention provides an application of the photocurable resin composition provided in this application in the field of photocuring; preferably, the application of the photocurable resin composition in the manufacturing of printed circuit boards, lead frames, and semiconductor packaging substrates.

[0020] Using the technical solution of the present invention, the compound represented by general formula (I) is a copolymer of (meth)acrylic acid and styrene, which has a high glass transition temperature and strong rigidity, and can give the photocurable composition excellent adhesion and resolution; the compound represented by general formula (II) is a copolymer of (meth)acrylic acid and (meth)acrylic acid cyclohexyl ester, which has excellent flexibility due to the cyclohexyl group and good hydrophobic properties, and can give the photocurable composition excellent resolution and flexibility; the compound represented by general formula (III) is a copolymer of (meth)acrylic acid and alkyl-substituted (meth)acrylic acid alkyl ester, in which, during the development process, the alkali-soluble resin containing long-chain alkyl substituents is dispersed in the developer to form micelles. These micelles can contain more hydrophobic initiators or monomers, giving the photocurable composition excellent developer dispersion stability. The photocurable resin composition provided in this application contains a mixture of compounds represented by general formulas (I), (II) and (III). By limiting the content of each repeating unit within the above range, the synergistic effect of the three compounds can be achieved, thereby enabling the photocurable composition as a photoresist to have excellent adhesion, resolution, flexibility and developer dispersion properties during application.

[0021] Compared to other ranges, limiting the amounts of alkali-soluble resin, polymeric monomer, and photoinitiator to the above ranges not only helps improve the storage stability of the photocurable resin composition and suppress its overflow, but also helps improve the photosensitivity and resolution of the photocurable resin composition.

[0022] In summary, the inventors restructured the structure and properties of alkali-soluble resins, breaking down the original multifunctional single alkali-soluble resin design into several specific functional compounds. By combining the above-mentioned functional compounds in appropriate proportions, along with the aforementioned amounts of polymeric monomers and photoinitiators, a photocurable resin composition with excellent comprehensive properties, including high adhesion, high resolution, good development and dispersion performance, and flexibility, was obtained, thus meeting the needs of PCB production in the IC packaging substrate field. Attached Figure Description

[0023] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0024] Figure 1 The SEM image (scale bar is 100 μm) of the sample with a resolution test of 10 μm in Example 1 is shown;

[0025] Figure 2 The SEM image (scale bar is 200 μm) of the sample with a resolution of 15 μm in Comparative Example 2 is shown. Detailed Implementation

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0027] As described in the background section, existing photocurable resin compositions suffer from the problem of simultaneously achieving excellent adhesion, film removal time, and developer dispersion performance. To address these technical problems, this application provides a photocurable resin composition, comprising, by weight: 45-60 parts of an alkali-soluble resin, 30-50 parts of a polymeric monomer, and 2.5-5 parts of a photoinitiator; the alkali-soluble resin comprises a mixture of compounds shown in general formulas (I), (II), and (III).

[0028]

[0029] Each R1 and each R2 independently includes, but is not limited to, a hydrogen atom or a methyl group; R' includes, but is not limited to, substituted or unsubstituted alkyl groups of C2 to C8; based on the percentage of the molecular weight of the compound represented by general formula (I), the content of the segment corresponding to x1 is 25 to 35 wt%, and the content of the segment corresponding to y1 is 65 to 75 wt%; based on the percentage of the molecular weight of the compound represented by general formula (II), the content of the segment corresponding to x2 is 20 to 35 wt%, and the content of the segment corresponding to y2 is 65 to 80 wt%; based on the percentage of the molecular weight of the compound represented by general formula (III), the content of the segment corresponding to x3 is 20 to 30 wt%, and the content of the segment corresponding to y3 is 70 to 80 wt%.

[0030] The compound represented by general formula (I) is a copolymer of (meth)acrylic acid and styrene, which has a high glass transition temperature and strong rigidity, thus giving the photocurable composition excellent adhesion and resolution. The compound represented by general formula (II) is a copolymer of (meth)acrylic acid and cyclohexyl methacrylate. Due to the excellent flexibility of the cyclohexyl group, it also has good hydrophobic properties, thus giving the photocurable composition excellent resolution and flexibility. The compound represented by general formula (III) is a copolymer of (meth)acrylic acid and alkyl-substituted alkyl methacrylate. During the development process, the alkali-soluble resin containing long-chain alkyl substituents is dispersed in the developer to form micelles. These micelles can contain more hydrophobic initiators or monomers, thus giving the photocurable composition excellent developer dispersion stability. The photocurable resin composition provided in this application contains a mixture of compounds represented by general formulas (I), (II) and (III). By limiting the content of each repeating unit within the above range, the synergistic effect of the three compounds can be achieved, thereby enabling the photocurable composition as a photoresist to have excellent adhesion, resolution, flexibility and developer dispersion properties during application.

[0031] Compared to other ranges, limiting the amounts of alkali-soluble resin, polymeric monomer, and photoinitiator to the above ranges not only helps improve the storage stability of the photocurable resin composition and suppress its overflow, but also helps improve the photosensitivity and resolution of the photocurable resin composition.

[0032] In summary, the inventors restructured the structure and properties of alkali-soluble resins, breaking down the original multifunctional single alkali-soluble resin design into several specific functional compounds. By combining the above-mentioned functional compounds in appropriate proportions, along with the aforementioned amounts of polymeric monomers and photoinitiators, a photocurable resin composition with excellent comprehensive properties, including high adhesion, high resolution, good development and dispersion performance, and flexibility, was obtained, thus meeting the needs of PCB production in the IC packaging substrate field.

[0033] In a preferred embodiment, based on the percentage of the molecular weight of the compound represented by general formula (I), the content of the chain segment corresponding to x1 is 27-33 wt%, and the content of the chain segment corresponding to y1 is 67-73 wt%; based on the percentage of the molecular weight of the compound represented by general formula (II), the content of the chain segment corresponding to x2 is 25-33 wt%, and the content of the chain segment corresponding to y2 is 67-75 wt%; based on the percentage of the molecular weight of the compound represented by general formula (III), the content of the chain segment corresponding to x3 is 23-28 wt%, and the content of the chain segment corresponding to y3 is 72-77 wt%.

[0034] The content of the corresponding segments x1 and y1 is not limited to the ranges mentioned above. Limiting them to these ranges is beneficial for improving the glass transition temperature and rigidity of the compound represented by general formula (I), thereby improving the adhesion and resolution of the photocurable composition. The content of the corresponding segments x2 and y2 is not limited to the ranges mentioned above. Limiting them to these ranges is beneficial for improving the flexibility and hydrophobicity of the compound represented by general formula (II), thereby improving the resolution and flexibility of the photocurable composition. The content of the corresponding segments x3 and y3 is not limited to the ranges mentioned above. Limiting them to these ranges is beneficial for improving the formation of micelles in the compound represented by general formula (III) during development, thereby improving the developer dispersion performance of the photocurable composition. Compared to other ranges, limiting the content of the corresponding segments x1, y1, x2, y2, x3, and y3 to the ranges mentioned above is beneficial for improving the overall performance of the photocurable composition, including adhesion, resolution, flexibility, and developer dispersion.

[0035] In a preferred embodiment, the weight ratio of the compound represented by formula (I), the compound represented by formula (II), and the compound represented by formula (III) is (20–45):(10–25):(4–9). The weight ratio of the compounds represented by formulas (I), (II), and (III) includes, but is not limited to, the above range. Limiting it to the above range is beneficial to better exert the synergistic effect of the three compounds and better utilize the function of the repeating units in each compound, thereby further improving the overall performance of the photocurable composition, such as adhesion, resolution, flexibility, and developer dispersibility.

[0036] In a preferred embodiment, in the compound of general formula (III), when all R's are C2-C4 substituted or unsubstituted alkyl groups, the content of the segment corresponding to x3 is 20-30 wt% and the content of the segment corresponding to y3 is 70-80 wt%, based on the percentage of the molecular weight of the compound of general formula (III); in the compound of general formula (III), some R's are C2-C4 substituted or unsubstituted alkyl groups and another part of R's are C5-C8 substituted or unsubstituted alkyl groups. When the alkyl group is used, the content of the segment corresponding to x3 is 22-30 wt% and the content of the segment corresponding to y3 is 70-78 wt% based on the percentage of the molecular weight of the compound represented by general formula (III). When all R' in the compound represented by general formula (III) are substituted or unsubstituted alkyl groups of C5-C8, the content of the segment corresponding to x3 is 24-30 wt% and the content of the segment corresponding to y3 is 70-76 wt% based on the percentage of the molecular weight of the compound represented by general formula (III). The content of the segments corresponding to x3 and y3 includes, but is not limited to, the above ranges. Limiting them to the above ranges is beneficial to further improve the formation of micelles in the compound represented by general formula (III) during the development process, thereby further improving the developer dispersion performance of the photocurable composition.

[0037] To further improve the developer dispersion performance of the photocurable resin composition, preferably, the weight ratio of substituted or unsubstituted alkyl groups of C2 to C4 to substituted or unsubstituted alkyl groups of C5 to C8 is (50 to 80):(20 to 50).

[0038] In a preferred embodiment, in the compound of general formula (III), when all R's are butyl, the content of the segment corresponding to x3 is 20-30 wt% and the content of the segment corresponding to y3 is 70-80 wt% based on the percentage of the molecular weight of the compound of general formula (III); in the compound of general formula (III), when some R's are isooctyl and the other part of R's are butyl, the content of the segment corresponding to x3 is 22-30 wt% and the content of the segment corresponding to y3 is 70-78 wt% based on the percentage of the molecular weight of the compound of general formula (III); in the compound of general formula (III), when all R's are isooctyl, the content of the segment corresponding to x3 is 24-30 wt% and the content of the segment corresponding to y3 is 70-76 wt% based on the percentage of the molecular weight of the compound of general formula (III). The content of the corresponding segments of x3 and y3 includes, but is not limited to, the above range. Limiting them to the above range is beneficial to further improve the formation of micelles in the compound shown in general formula (III) during the development process, thereby further improving the developer dispersion performance of the photocurable composition.

[0039] To further improve the developer dispersion performance of the photocurable resin composition, preferably, the weight ratio of isooctyl to butyl is (20-50):(50-80).

[0040] In a preferred embodiment, the weight ratio of the alkali-soluble resin, the polymeric monomer, and the photoinitiator can be 45:50:3.5, 54:40:3, 54:41.5:4, 55:40:3.5, 57:38:3.5, 60:30:5, or 60:35:2.5.

[0041] In a preferred embodiment, the compound of general formula (I) has a weight-average molecular weight of 25,000 to 60,000, an acid value of 160 to 230 mg KOH / g, and a molecular weight distribution index of 1.0 to 3.0. The weight-average molecular weight and molecular weight distribution index of the compound of general formula (I) include, but are not limited to, the above ranges. Limiting them to these ranges is beneficial for improving tolerance to the developer, shortening the development time, and improving the resolution of the final PCB circuit pattern. Similarly, the acid value of the compound of general formula (I) includes, but is not limited to, the above ranges. Limiting it to these ranges is beneficial for shortening the stripping time and improving the resolution of the final PCB circuit pattern.

[0042] In a preferred embodiment, the compound of general formula (II) has a weight-average molecular weight of 25,000 to 60,000, an acid value of 130 to 230 mg KOH / g, and a molecular weight distribution index of 1.0 to 3.0. The weight-average molecular weight and molecular weight distribution index of the compound of general formula (II) include, but are not limited to, the above ranges. Limiting them to these ranges is beneficial for improving tolerance to the developer, shortening the development time, and improving the resolution of the final PCB circuit pattern. Similarly, the acid value of the compound of general formula (II) includes, but is not limited to, the above ranges. Limiting it to these ranges is beneficial for shortening the stripping time and improving the resolution of the final PCB circuit pattern.

[0043] In a preferred embodiment, the compound of general formula (III) has a weight-average molecular weight of 25,000 to 60,000, an acid value of 130 to 200 mg KOH / g, and a molecular weight distribution index of 1.0 to 3.0. The weight-average molecular weight and molecular weight distribution index of the compound of general formula (III) include, but are not limited to, the above ranges. Limiting them to these ranges is beneficial for improving the dispersibility and stability of the developer, shortening the development time, and improving the resolution of the final PCB circuit pattern. Similarly, the acid value of the compound of general formula (III) includes, but is not limited to, the above ranges. Limiting it to these ranges is beneficial for shortening the stripping time and improving the resolution of the final PCB circuit pattern.

[0044] In a preferred embodiment, the polymerizing monomer is an olefinically unsaturated double-bonded monomer; preferably, the polymerizing monomer includes, but is not limited to, one or more monomers from the group consisting of ethoxylated nonylphenol acrylate monomers, ethoxylated bisphenol A di(meth)acrylate monomers, polyethylene glycol di(meth)acrylate monomers, trimethylolpropane tri(meth)acrylate monomers, and ethoxylated trimethylolpropane tri(meth)acrylate monomers. Compared to other types, using the above-mentioned polymerizing monomers is beneficial for improving the bottom residual of the resist circuit and for improving the resolution of the photocurable resin composition, thereby improving the resolution of the final IC packaging substrate and PCB, etc.

[0045] To further improve the resolution of the photocurable resin composition, more preferably, the polymerizing monomers include, but are not limited to, bisphenol A di(meth)acrylate monomers; more preferably, 4-bisphenol A di(meth)acrylate and / or 10-bisphenol A di(meth)acrylate.

[0046] To further improve the bottom residual foot of the anti-corrosion line, more preferably, the polymerizing monomers include, but are not limited to, a mixture of bisphenol A di(meth)acrylate monomers and trimethylolpropane tri(meth)acrylate monomers.

[0047] In a preferred embodiment, the photoinitiator includes, but is not limited to, one or more of the group consisting of 2-(o-chlorophenyl)-4,5-diphenylimidazolium dimer, 2-(o-chlorophenyl)-4,5-di(methoxyphenyl)imidazolium dimer, 2-(o-fluorophenyl)-4,5-diphenylimidazolium dimer, 2-(o-methoxyphenyl)-4,5-diphenylimidazolium dimer, 2-(p-methoxyphenyl)-4,5-diphenylimidazolium dimer, and 2,2',4-tris(2-chlorophenyl)-5-(3,4-dimethoxyphenyl)-4',5'-diphenyl-1,1'-diimidazole. Compared to other types, using the above-mentioned photoinitiators is beneficial for improving the resolution of the photocurable resin composition.

[0048] To further improve the photosensitivity and resolution of the photocurable resin composition, preferably, the photocurable resin composition further includes 3 to 30 wt% sensitizer, based on the weight percentage of the photoinitiator.

[0049] In a preferred embodiment, the sensitizer includes, but is not limited to, one or more compounds from the group consisting of benzophenone compounds, pyrazoline compounds, acridine compounds, coumarin compounds, and anthracene compounds. Compared to other types, using the above-mentioned types of sensitizers is beneficial for further improving the photosensitivity and resolution of the photocurable resin composition.

[0050] Preferably, the sensitizer includes, but is not limited to, one or more of the group consisting of benzophenone, N,N'-tetramethyl-4,4'-diaminobenzophenone, N,N'-tetraethyl-4,4'-diaminobenzophenone, 4-methoxy-4'-dimethylaminobenzophenone, and N-phenylglycine. Benzophenone is more preferably preferred.

[0051] To further improve the photosensitivity and resolution of the photocurable resin composition, more preferably, the sensitizer is benzophenone.

[0052] In a preferred embodiment, the photocurable resin composition further includes, by weight, 0.5 to 5.0 parts of additives. The amount of additives used includes, but is not limited to, the above range; limiting it within this range is beneficial for better utilization of the additives' respective functions. Preferably, the additives include, but are not limited to, one or more of dyes, colorants, plasticizers, defoamers, leveling agents, adhesion promoters, and polymerization inhibitors.

[0053] A second aspect of this application also provides an application of the above-described photocurable resin composition in the field of photocuring. Preferably, the photocurable resin composition is used in the manufacture of printed circuit boards, lead frames, and semiconductor packaging substrates.

[0054] By combining the above-mentioned functionalized compounds in the specified proportions, along with the above-mentioned amounts of polymeric monomers and photoinitiators, a photocurable resin composition with excellent comprehensive properties, including high adhesion, high resolution, good development and dispersion performance, and flexibility, is obtained, thereby meeting the PCB production requirements in the IC packaging substrate field. The photoresist prepared using the above formulation can meet the precision PCB manufacturing needs of the IC packaging substrate field.

[0055] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0056] Preparation method of alkali-soluble resin

[0057] Compounds were prepared using the monomer types and amounts shown in Table 1. The weight percentage of each monomer's corresponding chain segment relative to the compound represented by the corresponding general formula is expressed as x1 to x3 and y1 to y3, respectively. Compound A-1 was prepared by copolymerization of three comonomers: methacrylic acid, styrene, and cyclohexyl methacrylate. Therefore, the structure of compound A-1 contains all three corresponding repeating chain segments. Compound A-2 was prepared by copolymerization of four comonomers: methacrylic acid, styrene, cyclohexyl methacrylate, and isooctyl acrylate. Therefore, the structure of compound A-2 contains all four corresponding repeating chain segments. Thus, neither compound A-1 nor A-2 satisfies the general formula described above in this application.

[0058] The acid value was determined by weighing 0.5 g of the synthesized polymer solution in an Erlenmeyer flask, adding 30 mL of a mixed solvent (toluene / methanol mass ratio = 70 / 30) to dilute and dissolve it, adding phenolphthalein solution as an indicator, and then titrating with 0.02 N potassium hydroxide ethanol solution. The acid value was calculated as the number of milligrams of potassium hydroxide required to neutralize 1 g of polymer sample. The weight-average molecular weight and molecular weight distribution index were determined by gel permeation chromatography, and derived using the standard curve of standard polystyrene. The acid value, weight-average molecular weight, and molecular weight distribution index of the compounds shown in Tables 1 and 2 were tested, and the results are shown in Table 1.

[0059] Mix the monomers corresponding to those in Table 1 according to the weight ratio shown in Table 1 (total 300g) and set aside. Mix this mixture with 6.0g of photoinitiator AIBN, 180g of butanone, and 30g of propylene glycol methyl ether to obtain a mixed solution. Stir and dissolve the solution, and set aside as solution X1. Add 60g of butanone and 30% by weight of solution X1 to a three-necked flask equipped with nitrogen protection and a reflux condenser. Heat the flask to 80°C in an oil bath, and then slowly add the remaining 70% by weight of solution X1 dropwise using a peristaltic pump. Complete the addition within 3 hours and maintain the temperature for 4 hours. Add 15g of butanone solution X2 containing 0.5g of AIBN, and complete the addition within 0.5 hours. Maintain the temperature and stir for 1 hour. Add 0.5g of AIBN solution X2 again. 15g of butanone solution X3 of AIBN was added within 0.5h, and the mixture was kept warm and stirred for 1h. The system was then heated to 95℃ and kept warm and stirred for 2h. The reaction was then stopped by cooling. The corresponding compounds AI-1 to AI-3, AII-1 to AII-3, AIII-1 to AIII-3, as well as compounds A-1 and A-2 were collected.

[0060] Table 1

[0061]

[0062] Table 2

[0063]

[0064] Preparation of UV-curable resin compositions

[0065] According to the formulations in Tables 3, 4, and 5 below, the components were mixed in proportion, 60 parts by weight of acetone were added, and then stirred thoroughly until completely dissolved to prepare a resin composition solution with a solid content of 40 wt%. This solution was then uniformly coated onto the surface of a 15 μm thick PET support film using a coating machine and baked in a 90°C oven for 8 minutes to form a 25 μm thick dry film resist layer, which appeared blue-green under yellow light. Finally, a 20 μm thick polyethylene film protective layer was laminated onto its surface to obtain a three-layer photosensitive dry film.

[0066] The types, sources, and corresponding numbers of the polymer monomers, photoinitiators, and additives used in all the embodiments and comparative examples of this application are as follows:

[0067] (1) Polymer monomers:

[0068] B-1: (10) Bisphenol A dimethacrylate ester with ethoxylation, molecular weight 804 (Sartoma);

[0069] B-2: (4) Bisphenol A dimethacrylate ester with ethoxylated 540 (Sartoma);

[0070] B-3: (6) Ethylene oxide (12) propionyl oxide dimethacrylate, molecular weight 1114 (Meiyuan);

[0071] B-4: (6) Ethylene oxide trimethylolpropane triacrylate, molecular weight 560 (Sartoma);

[0072] (2) Photoinitiator:

[0073] C-1: 2-(o-chlorophenyl)-4,5-diphenylimidazolium dimer (Changzhou Qiangli Electronic New Materials); C-2: N,N'-tetraethyl-4,4'-diaminobenzophenone (Changzhou Qiangli Electronic New Materials);

[0074] C-3: Benzophenone (West Asia Chemicals);

[0075] (3) Additives:

[0076] D-1: Diamond Green (Shanghai Bailingwei Chemical Technology Co., Ltd.);

[0077] D-2: Leuco Crystal Violet (Shanghai Bailingwei Chemical Technology Co., Ltd.);

[0078] D-3: p-Toluenesulfonamide (Shanghai TIXIA Chemical Co., Ltd.);

[0079] D-4: 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate (Aladdin).

[0080] Table 3

[0081]

[0082]

[0083] Table 4

[0084]

[0085] Table 5

[0086]

[0087] The following describes the sample preparation methods (including film application, exposure, development, and electroplating), sample evaluation methods, and evaluation results of the examples and comparative examples.

[0088] (1) Sample preparation method

[0089] [Screen protector]

[0090] The copper-clad laminate is polished using a grinding machine, washed with water, and dried to obtain a bright and fresh copper surface. The temperature of the pressure roller of the laminating machine is set at 110℃, the conveying speed is 1.5m / min, and heat lamination is performed under standard pressure.

[0091]

exposure

[0092] After the film was applied, the sample was left to stand for more than 15 minutes, then exposed using an Adtec IP-6 exposure machine. The sensitivity was tested using a Stouffer 41-step exposure scale, with the exposure count controlled at 15 divisions.

[0093]

development

[0094] After exposure, the sample should be allowed to stand for at least 15 minutes. The development temperature is 30℃, and the pressure is 1.2 kg / cm². 2 The developer is a 1 wt% sodium carbonate aqueous solution, and the development time is 2.0 times the minimum development time. After development, the product is washed with water and dried.

[0095] (2) Evaluation Methods

[0096] [Evaluation of film removal speed]

[0097] Take a substrate that has been laminated, exposed, and developed, cut it into a 4×5cm square, and place it in a beaker containing 100mL of stripping solution (3wt% sodium hydroxide concentration, 50℃). Record the time it takes for the dry film to completely peel off. The stripping speed is evaluated by testing the stripping time; the shorter the stripping time, the faster the stripping speed.

[0098] [Resolution Evaluation]

[0099] Exposure is performed using a mask with a wiring pattern having an exposed portion and an unexposed portion with a width of n:n (n being 5–40 μm). After development at 2.0 times the minimum development time, the minimum mask width at which the cured resist lines normally form is taken as the resolution value, and observed using a magnifying glass. The smaller the number read, the better the resolution.

[0100] [Evaluation of Adhesion]

[0101] Photosensitive dry film resist is laminated onto a copper plate using a hot-pressing method. A mask with a wiring pattern having an exposed and unexposed portion and a width of n:400 (n being 5–40 μm) is used for exposure. After development at 2.0 times the minimum development time, the minimum mask width at which the cured resist lines normally form is taken as the adhesion value, and observed using a magnifying glass. The smaller the number read, the better the adhesion.

[0102] [Evaluation of flexibility]

[0103] Dry film resist was laminated onto an FPC substrate to serve as a test piece for evaluating flexibility. After lamination, the sample was allowed to stand for at least 15 minutes, then exposed using an Adtec IP-6 exposure machine with 15 exposure intervals. Development was performed for twice the minimum development time, resulting in a flexibility evaluation substrate with dry film resist laminated on the FPC substrate. Flexibility was evaluated using a mandrel tester. The flexibility evaluation substrate was cut into strips 2 cm wide and 10 cm long. These strips were rubbed 180° against a cylindrical rod 10 times, and the presence of peeling or cracking of the dry film lines on the substrate was observed. The diameter of the corresponding cylindrical rod where no peeling or cracking of the dry film was observed and recorded. A smaller number indicates better flexibility.

[0104] Judgment criteria: ○ indicates: 5-6mm without cracks; △ indicates: 7mm without cracks; × indicates: 8mm and above without cracks.

[0105] Evaluation of developer dispersibility

[0106] Dissolve 18.0 g of dry film resist in 1 L of 1.0 wt% Na₂CO₃ solution and stir until completely dissolved; then transfer the solution to a small foaming machine to simulate developing conditions at a solution temperature of 30°C and a pressure of 1.2 kg / cm². 2 Under these conditions, turn on the water pump and circulate the spray for 60 minutes, then stop. Observe the occurrence of oily condensates on the surface of the solution, the inner wall of the tank, or the bottom of the foaming machine.

[0107] Judgment criteria: ○ indicates that no condensate appears on the solution surface or at the bottom of the tank; △ indicates that no condensate appears on the solution surface, but a small amount of condensate appears at the bottom of the tank; × indicates that a large amount of condensate appears on both the solution surface and at the bottom of the tank.

[0108] (3) Evaluation results of performance such as photosensitivity, resolution, adhesion, flexibility, decoction speed, and electroplating resistance (see Tables 6 and 7) Figure 1 and Figure 2 )

[0109] Table 6

[0110] Example 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Adhesion / μm 9 9 11 10 10 9 14 10 8 8 8 7 7 8 Resolution / μm 10 9 10 9 10 9 15 10 7 8 8 7 8 8 Film removal time / s 55 56 51 54 49 54 48 52 53 52 49 55 54 51 Flexibility level ○ ○ ○ ○ ○ ○ ○ △ ○ ○ ○ ○ ○ ○ Developer dispersibility grade ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○

[0111] Table 7

[0112] Comparative Example 1 2 3 4 5 Adhesion / μm 8 10 14 9 13 Resolution / μm 9 15 11 8 13 Film removal time / s 55 60 51 66 56 Flexibility level ○ × ○ △ △ Developer dispersibility grade × ○ ○ × △

[0113] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0114] Compared to the examples, although the sample prepared from the photocurable resin composition in Comparative Example 1 had better resolution and adhesion, its developer dispersibility was significantly worse than that of the sample prepared in the examples of this application because the photocurable resin composition did not contain the compound represented by general formula (III). The photocurable resin composition in Comparative Example 2 did not contain the compound represented by general formula (II), resulting in insufficient flexible groups and a significantly reduced flexibility compared to the examples, with a resolution of 15 μm (e.g., ...). Figure 2 The value was significantly lower than that of Example 1 (e.g., Figure 1 The absence of the compound represented by general formula (I) in the photocurable resin composition of Comparative Example 3 resulted in a significant decrease in adhesion compared to the examples. In Comparative Example 4, compound A-1, obtained by copolymerizing methacrylic acid, styrene, and cyclohexyl methacrylate, failed to achieve sufficient developer dispersion stability, and the removal time was significantly longer than in the examples. In Comparative Example 5, compound A-2, obtained by copolymerizing methacrylic acid, styrene, cyclohexyl methacrylate, and isooctyl acrylate, failed to achieve sufficient developer dispersion, and the adhesion and resolution tended to decrease significantly compared to the examples.

[0115] Comparing all the embodiments and comparative examples, it can be seen that the photocurable resin composition provided in this application contains a mixture of compounds represented by general formulas (I), (II) and (III). By limiting the content of each repeating unit within the preferred range of this application, the synergistic effect of the three compounds can be achieved, thereby enabling the photocurable composition as a photoresist to have excellent adhesion, resolution, flexibility and developer dispersion properties during application.

[0116] Comparing Examples 2 and 5 with Example 7, it can be seen that the excessive amount of the compound shown in general formula (III) in Example 7 led to a decrease in the adhesion and resolution of the sample. This indicates that the weight ratio of the compounds shown in general formulas (I), (II) and (III) includes, but is not limited to, the preferred range of this application. Limiting it to the preferred range of this application is beneficial to better exert the synergistic effect of the three compounds and better exert the function of the repeating units in each compound, thereby further improving the overall performance of the photocurable composition, such as adhesion, resolution, flexibility and developer dispersibility.

[0117] Comparing Examples 2 and 5 with Example 8, it can be seen that in Example 8, the amount of the compound represented by general formula (I) is too large and the amount of flexible groups is insufficient, resulting in a decrease in the flexibility of the sample prepared.

[0118] Comparative Examples 9 to 12 show that the content of the corresponding segments x1 and y1 includes, but is not limited to, the preferred range of this application. Limiting them to the preferred range of this application is beneficial to improving the glass transition temperature and rigidity of the compound shown in general formula (I), thereby improving the adhesion and resolution of the photocurable composition. The content of the corresponding segments x2 and y2 includes, but is not limited to, the preferred range of this application. Limiting them to the preferred range of this application is beneficial to improving the flexibility and hydrophobic properties of the compound shown in general formula (II), thereby improving the resolution and flexibility of the photocurable composition. The content of the corresponding segments x3 and y3 includes, but is not limited to, the preferred range of this application. Limiting them to the preferred range of this application is beneficial to improving the formation of micelles in the compound shown in general formula (III) during development, thereby improving the developer dispersion performance of the photocurable composition. Compared to other ranges, limiting the content of the corresponding segments x1, y1, x2, y2, x3, and y3 to the preferred range of this application is beneficial to improving the overall performance of the photocurable composition, including adhesion, resolution, flexibility, and developer dispersion.

[0119] It should be noted that the terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in a sequence other than those described herein.

[0120] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A photocurable resin composition, characterized in that, The photocurable resin composition comprises, by weight, 45-60 parts of alkali-soluble resin, 30-50 parts of polymeric monomer and 2.5-5 parts of photoinitiator; The alkali-soluble resin comprises a mixture of compounds represented by general formulas (I), (II), and (III): （I）； (II); (III); Each R1 and each R2 is independently selected from a hydrogen atom or a methyl group; R' is selected from substituted or unsubstituted alkyl groups from C2 to C8; Based on the percentage of the molecular weight of the compound represented by the general formula (I), the content of the chain segment corresponding to x1 is 25-35 wt%, and the content of the chain segment corresponding to y1 is 65-75 wt%. Based on the percentage of the molecular weight of the compound represented by general formula (II), the content of the chain segment corresponding to x2 is 20-35 wt%, and the content of the chain segment corresponding to y2 is 65-80 wt%. Based on the percentage of the molecular weight of the compound represented by the general formula (III), the content of the chain segment corresponding to x3 is 20-30 wt%, and the content of the chain segment corresponding to y3 is 70-80 wt%.

2. The photocurable resin composition according to claim 1, characterized in that, Based on the percentage of the molecular weight of the compound represented by the general formula (I), the content of the chain segment corresponding to x1 is 27-33 wt%, and the content of the chain segment corresponding to y1 is 67-73 wt%. Based on the percentage of the molecular weight of the compound represented by general formula (II), the content of the chain segment corresponding to x2 is 25-33 wt%, and the content of the chain segment corresponding to y2 is 67-75 wt%. Based on the percentage of the molecular weight of the compound represented by the general formula (III), the content of the chain segment corresponding to x3 is 23-28 wt%, and the content of the chain segment corresponding to y3 is 72-77 wt%.

3. The photocurable resin composition according to claim 1 or 2, characterized in that, The weight ratio of the compound represented by general formula (I), the compound represented by general formula (II), and the compound represented by general formula (III) is (20-45):(10-25):(4-9).

4. The photocurable resin composition according to claim 1, characterized in that, In the compound represented by general formula (III), when all R' are substituted or unsubstituted alkyl groups of C2 to C4, the content of the segment corresponding to x3 is 20 to 30 wt% and the content of the segment corresponding to y3 is 70 to 80 wt% based on the percentage of the molecular weight of the compound represented by general formula (III). In the compound represented by general formula (III), when part of the R' is a substituted or unsubstituted alkyl group of C2 to C4 and the other part of the R' is a substituted or unsubstituted alkyl group of C5 to C8, the content of the segment corresponding to x3 is 22 to 30 wt% and the content of the segment corresponding to y3 is 70 to 78 wt% based on the percentage of the molecular weight of the compound represented by general formula (III); the weight ratio of the substituted or unsubstituted alkyl group of C2 to C4 to the substituted or unsubstituted alkyl group of C5 to C8 is (50 to 80): (20 to 50); In the compound represented by general formula (III), when all R' are substituted or unsubstituted alkyl groups of C5 to C8, the content of the segment corresponding to x3 is 24 to 30 wt% and the content of the segment corresponding to y3 is 70 to 76 wt% based on the percentage of the molecular weight of the compound represented by general formula (III).

5. The photocurable resin composition according to claim 4, characterized in that, In the compound represented by general formula (III), when all R's are butyl groups, the content of the x3 corresponding chain segment is 20-30 wt% and the content of the y3 corresponding chain segment is 70-80 wt%, based on the percentage of the molecular weight of the compound represented by general formula (III). In the compound represented by general formula (III), when part of R' is isooctyl and the other part of R' is butyl, the content of the segment corresponding to x3 is 22-30 wt% and the content of the segment corresponding to y3 is 70-78 wt% based on the percentage of the molecular weight of the compound represented by general formula (III); the weight ratio of isooctyl to butyl is (20-50):(50-80). In the compound represented by general formula (III), when all R's are isooctyl groups, the content of the x3 corresponding chain segment is 24-30 wt% and the content of the y3 corresponding chain segment is 70-76 wt%, based on the percentage of the molecular weight of the compound represented by general formula (III).

6. The photocurable resin composition according to any one of claims 1 to 5, characterized in that, The compound represented by general formula (I) has a weight-average molecular weight of 25,000 to 60,000, an acid value of 160 to 230 mg KOH / g, and a molecular weight distribution index of 1.0 to 3.

0. The compounds represented by general formula (II) have a weight-average molecular weight of 25,000 to 60,000, an acid value of 130 to 230 mg KOH / g, and a molecular weight distribution index of 1.0 to 3.

0. The compounds represented by general formula (III) have a weight-average molecular weight of 25,000 to 60,000, an acid value of 130 to 200 mg KOH / g, and a molecular weight distribution index of 1.0 to 3.

0.

7. The photocurable resin composition according to claim 6, characterized in that, The polymer monomer is an olefinic unsaturated double bond monomer.

8. The photocurable resin composition according to claim 7, characterized in that, The polymerizing monomer is selected from one or more of the following groups: ethoxylated nonylphenol acrylate monomers, ethoxylated bisphenol A di(meth)acrylate monomers, polyethylene glycol di(meth)acrylate monomers, trimethylolpropane tri(meth)acrylate monomers, and ethoxylated trimethylolpropane tri(meth)acrylate monomers.

9. The photocurable resin composition according to claim 8, characterized in that, The polymerization monomer is selected from bisphenol A di(meth)acrylate monomers; the bisphenol A di(meth)acrylate monomers are selected from 4-bisphenol A di(meth)acrylate and / or 10-bisphenol A di(meth)acrylate.

10. The photocurable resin composition according to claim 8, characterized in that, The polymerization monomer is selected from a mixture of bisphenol A di(meth)acrylate monomers and trimethylolpropane tri(meth)acrylate monomers.

11. The photocurable resin composition according to any one of claims 7 to 10, characterized in that, The photoinitiator is selected from one or more of the group consisting of 2-(o-chlorophenyl)-4,5-diphenylimidazolium dimer, 2-(o-chlorophenyl)-4,5-di(methoxyphenyl)imidazolium dimer, 2-(o-fluorophenyl)-4,5-diphenylimidazolium dimer, 2-(o-methoxyphenyl)-4,5-diphenylimidazolium dimer, 2-(p-methoxyphenyl)-4,5-diphenylimidazolium dimer, and 2,2',4-tris(2-chlorophenyl)-5-(3,4-dimethoxyphenyl)-4',5'-diphenyl-1,1'-diimidazole.

12. The photocurable resin composition according to claim 11, characterized in that, The photocurable resin composition further includes 3 to 30 wt% sensitizer, based on the weight percentage of the photoinitiator.

13. The photocurable resin composition according to claim 12, characterized in that, The sensitizer is selected from one or more of the following groups: benzophenone compounds, pyrazoline compounds, acridine compounds, coumarin compounds, and anthracene compounds.

14. The photocurable resin composition according to claim 12, characterized in that, The sensitizer is selected from one or more of the group consisting of benzophenone, N,N'-tetramethyl-4,4'-diaminobenzophenone, N,N'-tetraethyl-4,4'-diaminobenzophenone, 4-methoxy-4'-dimethylaminobenzophenone, and N-phenylglycine.

15. The photocurable resin composition according to claim 14, characterized in that, The sensitizer is benzophenone.

16. The photocurable resin composition according to claim 11, characterized in that, The photocurable resin composition further includes, by weight, 0.5 to 5.0 parts of additives; The additives are selected from one or more of dyes, colorants, plasticizers, defoamers, leveling agents, adhesion promoters, and polymerization inhibitors.

17. The use of a photocurable resin composition according to any one of claims 1 to 16 in the field of photocuring.

18. The application of a photocurable resin composition according to any one of claims 1 to 16 in the manufacture of printed circuit boards, lead frames, and semiconductor packaging substrates.

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