Photosensitive resin composition containing anthracene methyl sulfate quaternary ammonium salt photosensitizer and use thereof

Abstract

The application provides a photosensitive resin composition containing anthracene methyl sulfate quaternary ammonium salt photosensitizer and application thereof, and the photosensitizer is anthracene-9-methylene sulfate quaternary ammonium salt shown in formula (I) or anthracene-9,10-dimethylene sulfate diquaternary ammonium salt shown in formula (II). Compared with the anthracene photosensitizer on the market, the photosensitizer used in the application can effectively avoid the rupture of carbon-oxygen bond caused by p-pi conjugation, thereby significantly reducing the migration of small molecule fragments after initiation, effectively inhibiting the penetration and crystallization of polyethylene protective film, and reducing the risk of line short circuit; the introduction of sulfate quaternary ammonium salt ensures excellent liposolubility and good formula compatibility; it also has unique water solubility, which can effectively reduce the development waste in the later development process; it provides more flexible selection for the formula design of the photosensitive composition; and the photosensitizer can be widely applied in the fields of dry film, paint, coating, ink and molding material and the like.

Description

Technical Field

[0001] This invention belongs to the field of photosensitive resin technology, and more specifically, relates to a photosensitive resin composition containing anthracene methyl sulfate quaternary ammonium salt photosensitizer and its application. Background Technology

[0002] Photosensitive resin compositions are widely used as key pattern transfer materials in the manufacture of printed circuit boards (PCBs), lead frames (LFs), and semiconductor packaging (IC) substrates. Typically, the photosensitive resin composition is coated onto the surface of a PET support film, and after drying, a protective layer, such as a polyethylene film (PE) protective layer, is tightly bonded to its surface to form a photosensitive dry film (or dry film resist). In the pattern transfer process, the dry film resist is first bonded to a copper substrate, and a mask with a specific pattern is used to cover the dry film resist for pattern exposure. Then, a weakly alkaline aqueous solution is used as a developer to remove unexposed areas, followed by etching or electroplating to form the pattern. Finally, a stripping solution is used to peel off the cured dry film, thus achieving pattern transfer.

[0003] As electronic devices become increasingly miniaturized and denser, the requirements for circuit precision are constantly rising. To meet the demands of fine circuit manufacturing, photosensitive resin compositions need to possess higher resolution. To improve resolution, appropriate sensitizers need to be added to the photosensitive resin composition. For photosensitive resin compositions, a suitable photoinitiation system directly affects photosensitivity, resolution, and production yield.

[0004] Currently, small-molecule anthracene derivatives, such as 9,10-dibutoxyanthracene (DBA), 9,10-diacoxyanthracene (DAcOA), and 9,10-diphenylanthracene (DPHA), are widely used as photosensitizers. Typically, to obtain higher photosensitizing performance and resolution, these photosensitizers need to be used in combination with 2,4,5-triarylimidazolium dimers (HABI) (e.g., patent CN101568883B); however, such photosensitizer / photoinitiator combination systems usually face the following problems:

[0005] 1) Short-chain alkoxyanthracene derivatives (similar to DBA) with good solubility are prone to migration in the dry film after initiation due to their initiation mechanism. They can penetrate into the surface of the polyethylene (PE) protective film and form crystals, which can cause defects such as short circuits and open circuits in the resist pattern, or cause a decrease in photosensitivity due to the photosensitizer penetrating from the photosensitive layer.

[0006] 2) Due to the electron-withdrawing effect of the acyloxy anthracene group, the electron cloud density of the 9th and 10th anthracene rings of 9,10-diacyloxy anthracene photosensitizers (DAcOA) increases. As a result, the efficiency of this type of photosensitizer decreases during the catalytic curing reaction. The sidewall verticality of the cured photosensitive resin composition is poor, and the difference in line length between the top and bottom is large, forming an "inverted trapezoid" problem. In addition, the energy required for exposure of this type of photoinitiator increases, and the photobleaching efficiency decreases.

[0007] 3) Although DPHA has the advantage of high quantum yield, its solubility is poor due to its large conjugated system, high molecular rigidity;

[0008] 4) Anthracene photosensitizers such as DBA, DAcOA, and DPHA are all fat-soluble small organic molecule compounds and are not water-soluble. The direct consequence is that fat-soluble photosensitizers and their fragments are prone to accumulating in aqueous developer during the development process, producing precipitates and debris that easily adhere to the copper plate surface, causing problems such as residual copper or short circuits, thus affecting product yield.

[0009] Therefore, developing a novel photoinitiator system that combines good lipid and water solubility, low migration, photobleaching properties, and excellent development compatibility, and constructing high-performance photocurable resin compositions based on this system, has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0010] Therefore, the purpose of this invention is to overcome the above-mentioned defects in the prior art and provide anthracene photosensitizers and photosensitive resin compositions that have both good fat solubility and water solubility, low migration, and low electroplating pollution, as well as their applications.

[0011] This objective is achieved through the photosensitive resin composition comprising anthracene methylene sulfate quaternary ammonium salt photosensitizer according to the present invention, the photosensitive resist comprising the photosensitive resin composition, the photosensitive dry film, and the application of the photosensitive dry film in printed circuit boards, lead frames, semiconductor packaging substrates, solar cells, and photocurable inks. The present invention improves the formulation compatibility of existing dry film products, reduces initiator migration to PE films, and significantly reduces the generation of developer waste, thereby improving product yield.

[0012] Based on extensive literature review and experimental research, this invention identifies the following problems and proposes innovative improvement solutions:

[0013] Anthracene compounds or anthracene derivatives, due to their unique structure, can undergo dimerization under light, thus being photobleached. This property effectively avoids the problem of excessive energy absorption by the upper photosensitizer during exposure, allowing the underlying photosensitive resin composition to receive light more fully. This enables the photosensitive resin composition to achieve uniform curing during exposure, resulting in better resolution. For example, patent CN101218538B discloses 9,10-dialkoxyanthracene photosensitizers, CN110446976B discloses alkoxyanthracene or phenylanthracene photosensitizers, and CN116300313A discloses 9,10-diacyloxyanthracene or 9,10-diphenoxyanthracene photosensitizers. All of these anthracene photosensitizers exhibit good resolution and adhesion.

[0014] However, this invention has found that: 9,10-dialkoxyanthracene photosensitizers experience breakage of the CO bond at positions 9 and 10 during exposure, leading to dimerization of the anthracene ring and the release of small alkoxy fragments. These small fragments migrate from the cured photosensitive resin composition into the electroplating solution during subsequent electroplating processes, causing contamination and affecting the lifespan of the plating solution and the electroplating effect. 9,10-diacoxyanthracene (DAcOA) photosensitizers, due to the electron-withdrawing effect of the acyloxy group, result in an increased electron cloud density at positions 9 and 10 of the anthracene ring. Consequently, the efficiency of these photosensitizers in catalyzing the curing reaction decreases, leading to poor verticality of the sidewalls of the cured photosensitive resin composition and a large difference in line length between the top and bottom, forming an "inverted trapezoidal" shape. Furthermore, the energy required for exposure of these photoinitiators increases, reducing photobleaching efficiency. 9,10-diarylanthracene photosensitizers, due to their rigid molecular structure, have significantly reduced solubility, greatly impacting the uniformity and consistency of the product.

[0015] Furthermore, this invention also discovered that anthracene photosensitizers such as DBA, DAcOA, and DPHA are all fat-soluble small-molecule organic photosensitizers and cannot be dissolved in the aqueous phase. However, in most cases, the development process is usually carried out in an aqueous solution of Na2CO3. Therefore, the direct consequence is that fat-soluble photosensitizers and their fragments are prone to accumulating in the aqueous developer during the development process, producing precipitates and debris that adhere to the copper plate surface, causing problems such as residual copper or short circuits, thus affecting product yield.

[0016] Based on the above findings, this invention proposes an anthracene methylene sulfate quaternary ammonium salt photosensitizer and a compatible photosensitive resin composition to improve the formulation compatibility and water solubility of existing dry film products, reduce the migration of initiators to PE films, and at the same time greatly reduce the generation of developing waste and improve product yield.

[0017] (a) Photosensitive resin composition

[0018] A first aspect of the present invention provides a photosensitive resin composition, based on 100 parts by weight of the photosensitive resin composition, comprising the following components: alkali-soluble resin A: 50-65 parts; photopolymerizable monomer B: 35-50 parts, selected from monomers containing olefinic unsaturated double bonds; photoinitiator C: 2-5 parts, selected from diimidazole compounds; and photosensitizer D: 0.1-1 parts, wherein the photosensitizer D is an anthracene-9-methylene sulfate quaternary ammonium salt having the structure shown in formula (I) and / or anthracene-9,10-dimethylene sulfate diquaternary ammonium salt having the structure shown in formula (II).

[0019]

[0020] Wherein, R in equation (I) a R b R c and R d and R in equation (II) e R f R g R h R o R p R q and R r Each is independently selected from hydrogen, C1-C6 alkyl, C6-C12 aryl-substituted C1-C6 alkyl, C3-C12 heteroaryl-substituted C1-C6 alkyl, and C1-C6 alkoxy-substituted C1-C6 alkyl;

[0021] Wherein, R in equation (I) and equation (II) 1 R 2 R 3 R 4 R 5 R 6 R 7 R 8 and R 9 Each is independently selected from hydrogen, C1-C6 alkyl, C6-C12 aryl-substituted C1-C6 alkyl, C3-C12 heteroaryl-substituted C1-C6 alkyl, C1-C6 alkoxy-substituted C1-C6 alkyl, C3-C6 cycloalkyl, and halogen; optionally, the compounds in formula (I) R in part a R b R c and R d Any two elements in the equation (II) can optionally form a 3-8 elemented ring with N; optionally, the elements in equation (II) can be... R in part e R f R g and R hAny two elements in the equation (III) can optionally form a 3-8 elemented ring with N; optionally, the elements in equation (III) can be... R in part o R p R q and R r Any two elements in the set can be arbitrarily combined with N to form a 3-8 elemental ring.

[0022] The photosensitive resin composition is photocured via the following photoinduced free radical polymerization mechanism: the anthracene-9-methylene sulfate quaternary ammonium salt of formula (I) and / or the anthracene-9,10-dimethylene sulfate diquaternary ammonium salt of formula (II) are excited by visible light to generate anthracene free radicals, which initiate homolytic cleavage of the diimidazole compound to generate imidazole free radicals. The imidazole free radicals activate the monomer containing olefinic unsaturated double bonds, causing it to crosslink and cure.

[0023] As used in this article, the term "bisimidazole compound" refers to a compound containing two imidazole rings, which are optionally substituted at various positions.

[0024] As used herein, the term "alkyl" includes saturated aliphatic hydrocarbons containing both straight and branched chains. In some embodiments, the alkyl group has 1 to 20 carbon atoms, 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms. For example, the term "C1-C6 alkyl," and the alkyl portion of other groups mentioned herein (e.g., C1-C6 alkoxy), refers to a straight or branched group with 1 to 6 carbon atoms (e.g., methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, or n-hexyl).

[0025] As used herein, the term "cycloalkyl" includes saturated or unsaturated non-aromatic monocyclic or polycyclic (e.g., bicyclic) hydrocarbon rings (e.g., monocyclic such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc.). The cycloalkyl group may have 3 to 6 carbon atoms.

[0026] As used herein, the term "aryl" can include all carbon monocyclic or fused-ring polycyclic aromatic groups having a conjugated π-electron system. Aryl groups have 6 or 12 carbon atoms in a ring (or multiple rings). Most commonly, aryl groups have 6 carbon atoms in a ring. For example, as used herein, the term "C6-C12 aryl" refers to an aromatic group containing 6 to 12 carbon atoms, such as phenyl or naphthyl.

[0027] As used herein, the term "heteroaryl" includes a monocyclic or fused-ring polycyclic aromatic heterocyclic group having one or more heteroatom ring members (cyclic atoms), wherein the one or more heteroatom ring members are independently selected from O, S, and N in at least one ring. A heteroaryl group has 5 to 14 cyclic atoms, including 1 to 13 carbon atoms and 1 to 8 heteroatoms selected from O, S, and N.

[0028] Alkali-soluble resin A

[0029] According to the photosensitive resin composition provided by the present invention, the alkali-soluble resin is an acrylate copolymer containing aromatic groups. From the perspective of improving product resolution and chemical resistance, preferably, the copolymerization ratio of comonomers having aromatic groups is 50-70% based on the total mass of comonomers during the copolymerization process.

[0030] In some embodiments of the present invention, the alkali-soluble resin is obtained by copolymerization of one or more of (meth)acrylic acid, alkyl (meth)acrylate, benzyl (meth)acrylate, benzyl (meth)acrylate derivatives, phenyl (meth)acrylate, styrene, and styrene derivatives.

[0031] In some embodiments of the present invention, the alkali-soluble resin is copolymerized from (meth)acrylic acid and a copolymer unit selected from one or more of methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, hydroxyethyl (meth)acrylate, and styrene.

[0032] In some specific embodiments of the present invention, the comonomers of the alkali-soluble resin include methacrylic acid, methyl methacrylate, hydroxyethyl methacrylate, benzyl methacrylate, and styrene.

[0033] Furthermore, the alkali-soluble resin has a weight-average molecular weight of 20,000-60,000, an acid value of 160-220 mg KOH / g, and a molecular weight distribution index of 1.0-3.0.

[0034] In embodiments of the present invention, the content of alkali-soluble resin is 50-65 parts by weight, preferably 55-60 parts by weight. If the content is less than 50 parts by weight, there is a tendency for the resist to flow laminarly; if the content exceeds 65 parts by weight, there is a tendency for the resolution to decrease.

[0035] Photopolymerizable monomer B

[0036] According to the photosensitive resin composition provided by the present invention, the photopolymerizable monomer is selected from monomers containing olefinic unsaturated double bonds, preferably from olefinic unsaturated carboxylic acids and / or olefinic unsaturated carboxylic acid esters, and more preferably from (meth)acrylate monomers.

[0037] In a preferred embodiment of the present invention, the photopolymerizable monomer is selected from one or more of the following: methoxy polyethylene glycol monoacrylate, ethoxy(propoxy)nonylphenol acrylate, ethoxy(propoxy)bisphenol A di(meth)acrylate, ethoxy(propoxy)di(meth)acrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, ethoxy(propoxy)trimethylolpropane tri(meth)acrylate, di(trimethylolpropane)tetraacrylate, ethoxy(propoxy)pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol hexaacrylate.

[0038] In embodiments of the present invention, the content of the photopolymerizable monomer is 35-50 parts by weight, preferably 40-50 parts by weight, and more preferably 45-50 parts by weight. If the content is less than 35 parts by weight, there is a tendency for the sensitivity and chemical resistance of the photoresist to decrease; if the content exceeds 50 parts by weight, there is a tendency for the photosensitive resin composition to be difficult to form a thin film and for the photoresist to flow as a laminar adhesive.

[0039] Photoinitiator C

[0040] According to the photosensitive resin composition provided by the present invention, the photoinitiator may be selected from a diimidazole compound, preferably selected from 2,4,5-triarylimidazole dimers.

[0041] In a preferred embodiment of the present invention, the photoinitiator is selected from one or more of 2-(2-chlorophenyl)-4,5-diphenylimidazolium dimer, 2-(2-chlorophenyl)-4,5-di(methoxyphenyl)imidazolium dimer, 2-(2-fluorophenyl)-4,5-diphenylimidazolium dimer, 2-(2-methoxyphenyl)-4,5-diphenylimidazolium dimer, 2-(4-methoxyphenyl)-4,5-diphenylimidazolium dimer, and 2,2',4-tris(2-chlorophenyl)-5-(3,4-dimethoxyphenyl)-4',5'-diphenyl-1,1'-diimidazole.

[0042] In embodiments of the present invention, the content of photoinitiator is 2-5 parts by mass, preferably 2-4 parts by mass, and more preferably 2.5-3.5 parts by mass. If the content is less than 2 parts by mass, there is a tendency for the sensitivity and resolution of the photoresist to decrease; if the content exceeds 5 parts by mass, there is a tendency for the amount of developing debris to increase.

[0043] Photosensitizer D

[0044] According to the photosensitive resin composition provided by the present invention, the photosensitizer is anthracene-9-methylene sulfate quaternary ammonium salt having the structure shown in formula (I) and / or anthracene-9,10-dimethylene sulfate diquaternary ammonium salt having the structure shown in formula (II):

[0045] ,

[0046] R in equation (I) a R b R c and R d R in equation (II) e R f R g R h R o R p R q and R r and R in equation (I) and equation (II) 1 R 2 R 3 R 4 R 5 R 6 R 7 R 8 and R 9 Defined as described above.

[0047] In some embodiments according to the present invention, R in formula (I) a R b R c and R d and R in equation (II) e R f R g R h R o R p R q and R r Each is independently selected from hydrogen and C1-C6 alkyl, preferably, each is independently selected from C1-C6 alkyl.

[0048] In some embodiments according to the invention, R in formulas (I) and (II) 1 R 2 R 3 R 4 R 5 R 6 R 7 R 8 and R 9Each is independently selected from hydrogen, C1-C6 alkyl, C3-C6 cycloalkyl and halogen, more preferably, each is independently hydrogen.

[0049] As can be seen from the above structural formulas, in anthracene-9-methylene sulfate quaternary ammonium salt of formula (I) and anthracene-9,10-dimethylene sulfate diquaternary ammonium salt of formula (II), a sulfate-substituted methylene group is introduced at the 9- and / or 10-position of anthracene, resulting in a positive quaternary ammonium salt cation as the counter ion. Compared to existing anthracene-based photosensitizers, the introduction of the cation-anion pair ensures the water solubility of this structure; simultaneously, the presence of the quaternary ammonium salt ion containing an alkyl group also ensures the lipophilicity of this ionic compound. Furthermore, compared to existing DBA-based photosensitizers, it does not produce small molecule fragments and can be widely used in photocuring fields such as dry films, paints, coatings, inks, and molding materials.

[0050] In a preferred embodiment of the present invention, the photosensitizer is selected from one or more of anthracene-9-methylene sulfate monotetrabutyl quaternary ammonium salt (TM1) and anthracene-9,10-dimethylene sulfate ditetrabutyl quaternary ammonium salt (TM2).

[0051] In some specific embodiments of the present invention, the photosensitizer may have one of the following structures:

[0052] .

[0053] In embodiments of the present invention, the content of photosensitizer is 0.1-1 parts by mass, preferably 0.1-0.8 parts by mass, and more preferably 0.2-0.5 parts by mass. If the content is less than 0.1 parts by mass, the sensitivity of the photoresist tends to decrease; if the content exceeds 1 part by mass, there is a tendency for the photoresist underlayer to not cure completely, resulting in the photoresist cross-sectional shape being an "inverted trapezoid" and the resolution deteriorating.

[0054] The preparation strategies for the anthracene-9-methylene sulfate quaternary ammonium salt represented by formula (I) and the anthracene-9,10-dimethylene sulfate diquaternary ammonium salt represented by formula (II) can be universally derived through the typical synthetic routes of the examples. Those skilled in the art, based on conventional principles of organic synthesis and the specific preparation steps for compounds TM1 and TM2 in the examples, can clearly understand the general preparation logic of the anthracene-9-methylene sulfate quaternary ammonium salt photosensitizers. Those skilled in the art can derive the preparation methods for all anthracene-9-acetic acid or anthracene-9,10-diacetic acid and ammonium bisulfate of formula (I) and / or formula (II) by substituting the anthracene ring with different substituents and optimizing the reaction parameters.

[0055] The anthracene methylene sulfate quaternary ammonium salt photosensitizers of the present invention can be prepared using conventional synthetic methods in the art. For example, they can be prepared according to the decarboxylation mechanism described in the literature (e.g., Organic Letters, 2024, 26(27), 5856-5861).

[0056] A typical reaction procedure is as follows: Under a nitrogen atmosphere, anthracene acetic acid and ammonium persulfate are added to a round-bottom flask equipped with a magnetic stirrer, along with catalytic amounts of silver nitrate and 4,7-diphenyl-1,10-phenanthroline, as well as KH₂PO₄ and tetraalkylammonium hydrogen sulfate, dissolved in dichloromethane. The reaction is carried out at room temperature. After the reaction is completed by monitoring by thin-layer chromatography (TLC), the reaction system is washed with saturated brine, the organic phase is collected, dried over anhydrous sodium sulfate, and purified by column chromatography, with a yield typically reaching 80%-90%.

[0057] Additive E

[0058] In various embodiments of the present invention, the photosensitive resin composition may, as needed, further comprise one or more additives selected from dyes, photodevelopers, plasticizers, adhesion promoters, polymerization inhibitors, defoamers, and coating aids. Preferably, the total amount of the additives is 0.5-5.0 parts by weight.

[0059] (ii) Photosensitive dry film

[0060] A second aspect of the present invention provides a photosensitive dry film comprising, from bottom to top: a support layer; a photosensitive resist layer attached to the surface of the support layer; and a protective layer attached to the surface of the photosensitive resist layer, wherein the photosensitive resist layer is formed using a photosensitive resin composition provided in the first aspect of the present invention.

[0061] In some preferred embodiments of the present invention, the photosensitive dry film comprises, from bottom to top: a PET support layer, a photosensitive resist layer formed by coating and drying the surface of the PET support layer with the photosensitive resin composition provided in the first aspect of the present invention, and a PE protective layer.

[0062] (III) Applications of photosensitive dry film

[0063] The third aspect of the present invention provides applications of the above-mentioned photosensitive dry film in printed circuit boards, lead frames, semiconductor packaging substrates, solar cells, and photocurable inks.

[0064] This invention employs anthracene methylene sulfate quaternary ammonium salt compounds of formula (I) and / or formula (II) with a sulfate-substituted methylene group at the 9-position and / or 10-position as photosensitizers, which has significant advantages over existing DBA-type photosensitizers:

[0065] (1) By introducing the sulfate-substituted methylene group, the maximum absorption wavelength is red-shifted while maintaining the electron cloud density of polycyclic aromatic hydrocarbons. This is especially suitable for 405nm illumination systems, which improves photosensitive efficiency and makes more efficient use of the exposure light source energy, thereby greatly improving production efficiency.

[0066] (2) At the same time, it avoids the problem of alkoxy carbon-oxygen bond breakage caused by p-π conjugation in DBA, thereby significantly reducing the migration of small molecule fragments after initiation, effectively inhibiting the penetration and crystallization into the polyethylene protective film, and reducing the risk of short circuit in the circuit.

[0067] (3) Compared with conventional photosensitizers DBA, DPHA and DAcOA in the prior art, the photosensitizer of the present invention, by introducing sulfate quaternary ammonium salt, can ensure its excellent solubility in conventional organic solvents such as monomers without changing the maximum absorption wavelength and absorption intensity and retaining excellent photobleaching performance, and has good compatibility with the formulation; it also has unique water solubility, which can effectively reduce development waste in the later development process; and provides more flexible choices for the formulation design of photosensitive compositions.

[0068] In addition to the objectives, features and advantages described above, the present invention also has other potential technical advantages, providing a better solution for the development of related fields.

[0069] In summary, the photosensitive dry film provided by this invention has excellent resolution and adhesion, and its photosensitivity is higher than that of photosensitive resin compositions with added 9,10-dibutoxyanthracene photosensitizer. This is beneficial for improving the production efficiency of customers and meeting the needs of high-density and high-precision printed circuit boards. Furthermore, its excellent solubility in conventional organic solvents and excellent water solubility are extremely beneficial for the formulation development of photosensitive compositions. Attached Figure Description

[0070] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings, wherein:

[0071] Figure 1 It is the photosensitizer TM1 prepared in Example 1 of this invention. 1 H NMR spectrum;

[0072] Figure 2 It is the photosensitizer TM1 prepared in Example 1 of this invention. 13 C NMR spectrum;

[0073] Figure 3 It is the photosensitizer TM2 prepared in Example 2 of this invention. 1 H NMR spectrum;

[0074] Figure 4 It is the photosensitizer TM2 prepared in Example 2 of this invention. 13 C NMR spectrum;

[0075] Figure 5 This is the ultraviolet absorption spectrum of photosensitizer TM1 prepared in Example 1 of this invention;

[0076] Figure 6 This is the ultraviolet absorption spectrum of photosensitizer TM2 prepared in Example 2 of this invention;

[0077] Figure 7 This is the photobleaching curve of photosensitizer TM1 prepared in Example 1 of this invention under 405 nm light irradiation conditions;

[0078] Figure 8 This is the photobleaching curve of the photosensitizer TM2 prepared in Example 2 of the present invention under 405 nm light irradiation. Detailed Implementation

[0079] The present invention will be further described in detail below with reference to specific embodiments. The embodiments given are only for illustrating the present invention and are not intended to limit the scope of the present invention.

[0080] Example 1

[0081] Preparation of anthracene-9-methylene sulfate monotetrabutyl-n-butyl quaternary ammonium salt (photosensitizer TM1)

[0082]

[0083] Under a nitrogen atmosphere, anthracene-9-acetic acid (1.0 mmol), ammonium persulfate (3.0 mmol), AgNO3 (0.05 mmol, 5 mol%), 4,7-diphenyl-1,10-phenanthroline (L: 0.05 mmol, 5 mol%), KH2PO4 (1.2 mmol), and tetrabutylammonium hydrogen sulfate (1.2 mmol) were dissolved in dry dichloromethane (5 mL) at the indicated molar ratio in a round-bottom flask equipped with a magnetic stirrer. The mixture was stirred at room temperature for 12 hours until the reaction was completed as monitored by TLC, indicating that the anthracene-9-acetic acid was completely consumed. The reaction system was washed with saturated brine, the organic phase was collected, dried over anhydrous sodium sulfate, and purified by column chromatography (yield 85%).

[0084] The structural formula of the product anthracene-9-methylene sulfate monotetrabutyl-n-butyl quaternary ammonium salt (photosensitizer TM1) is as follows:

[0085]

[0086]

[0087] Example 2

[0088] Preparation of anthracene-9,10-dimethylene sulfate ditetrabutyl-n-butyl quaternary ammonium salt (photosensitizer TM2)

[0089]

[0090] Under a nitrogen atmosphere, anthracene-9,10-diacetic acid (1.0 mmol), ammonium persulfate (6.0 mmol), AgNO3 (0.0 mmol, 10 mol%), 4,7-diphenyl-1,10-phenanthroline (L: 0.1 mmol, 10 mol%), KH2PO4 (2.4 mmol), and tetrabutylammonium hydrogen sulfate (2.4 mmol) were dissolved in dry dichloromethane (7.5 mL) at the indicated molar ratio in a round-bottom flask equipped with a magnetic stirrer. The mixture was stirred at room temperature for 12 hours until the reaction was completed as monitored by TLC, indicating that the anthracene-9,10-diacetic acid was completely consumed. The reaction system was washed with saturated brine, the organic phase was collected, dried over anhydrous sodium sulfate, and purified by column chromatography (yield 85%).

[0091] The structural formula of the product anthracene-9,10-dimethylene sulfate ditetrabutyl-n-butyl quaternary ammonium salt (photosensitizer TM2) is as follows:

[0092]

[0093]

[0094] Ultraviolet-Vis absorption spectroscopy (UV-vis) measurement and photobleaching experiment

[0095] Ultraviolet-visible absorption spectra (UV-vis) were measured on a Shimadzu UV-1900 UV-Vis spectrophotometer using toluene as the solvent at a concentration of 4 × 10⁻⁶. -5 mol / L.

[0096] According to Beer-Lambert law, the molar extinction coefficient is ε = A. bn / c, where A bn ν is the absorbance of the UV-Vis absorption spectrum, and c is the concentration.

[0097] Photobleaching experiment: Using toluene as solvent, the changes in the UV-Vis absorption spectrum of the sample solution were measured by a Shimadzu UV-1900 UV-Vis spectrophotometer under a 450 nm LED.

[0098] Figure 5 This is the ultraviolet absorption spectrum of photosensitizer TM1; Figure 6 This is the ultraviolet absorption spectrum of photosensitizer TM2; Figure 7 and Figure 8The photobleaching curves of TM1 and TM2 under 405 nm illumination are shown in Table 1 below. The molar extinction coefficients of photosensitizers TM1 and TM2, as well as DBA, are also shown in Table 1.

[0099]

[0100] A comparison of the UV absorption spectra in Table 1 shows that the photosensitizer of this invention has a molar extinction coefficient close to that of DBA; simultaneously, through... Figures 5-8 A comparison of the ultraviolet absorption spectra shows that the photosensitizers TM1 and TM2 of the present invention have very good photobleaching performance, and photobleaching occurs within 60 min and 90 min, respectively.

[0101] Solubility test

[0102] Using acetone, toluene, methanol, and water as solvents, and a mixture of 5g of methoxy polyethylene glycol (350) monoacrylate, 20g of 10(ethoxy)bisphenol A dimethacrylate, 5g of 6(propoxy)bisphenol A dimethacrylate, 10g of 3(ethoxy)trimethylolpropane triacrylate, and 4g of di(trimethylolpropane)tetraacrylate as monomers (referred to as "monomers" in the table), the photosensitizers TM1-TM2, DBA, DPHA, and DAcOA from Examples 1-2 were tested for their solubility in various solvents and compatibility with monomers. The solute was added to the solvent at a ratio of 0.1g solute / 1g solvent (10% w / w), and the solubility was recorded according to the following grading criteria. The test results are shown in Table 2.

[0103] Excellent (rapid dissolution): Under room temperature and stirring conditions, a clear, transparent and homogeneous solution can be formed within 1 minute;

[0104] Medium (slow dissolution): Under room temperature and stirring conditions, a clear, transparent and uniform solution can be formed in more than 5 minutes; or it cannot be completely dissolved at room temperature, but a clear, transparent and uniform solution can be formed when heated to 50-60℃, and there is no obvious turbidity after returning to room temperature.

[0105] Poor (partially soluble): It cannot be completely dissolved in more than 5 minutes under room temperature and stirring conditions; or it can be completely dissolved when heated to 50-60℃, but becomes obviously turbid after returning to room temperature.

[0106]

[0107] As can be seen from the data in Table 2, compared with conventional photosensitizers DBA, DPHA and DAcOA in the prior art, the photosensitizers TM1 and TM2 of the present invention exhibit superior solubility in various commonly used organic solvents, good compatibility with monomers, and, more uniquely, excellent solubility in water as well, which is very helpful for the formulation design of photocurable compositions.

[0108] Examples 3-8 and Comparative Examples 1-7

[0109] Preparation of photosensitive resin compositions

[0110] Referring to the formulations shown in Table 3, the photosensitive resin compositions of the present invention in Examples 3-8 were prepared. Simultaneously, photosensitive resin compositions using existing photosensitizers in Comparative Examples 1-7 were prepared for comparison. Specifically, the components corresponding to the samples numbered 3-8 and 1-7 in Table 3 were mixed evenly to prepare the photosensitive resin compositions. To facilitate coating, acetone solvent could be added to adjust the viscosity to an appropriate level. Blank indicates no acetone was added.

[0111]

[0112] The components represented by the codes in Table 3 are explained below:

[0113] A (Alkali-soluble resin): Acrylic ester copolymer, solution polymerization, with a mass ratio of methacrylic acid / butyl methacrylate / benzyl methacrylate = 25 / 10 / 65; solvent is acetone, solid content is 46%, weight average molecular weight is 40,000, dispersity is 2.1, and acid value is 163 mg KOH / g. (Hunan Chuyuan New Materials Co., Ltd.)

[0114] B (photopolymerizable monomer) is composed of the following components (purchased from Sartoma Guangzhou Chemical Co., Ltd.): 5g of methoxy polyethylene glycol (350) monoacrylate, 20g of 10 (ethoxy) bisphenol A dimethacrylate, 5g of 6 (propoxy) bisphenol A dimethacrylate, 10g of 3 (ethoxy) trimethylolpropane triacrylate, and 4g of di (trimethylolpropane) tetraacrylate;

[0115] C (photoinitiator): 2,2'-bis(o-chlorophenyl)-4,4',5,5'-tetraphenyl-diimidazole (BCIM) (purchased from Jiuding Chemical);

[0116] E (additive) consists of the following ingredients (purchased from Anaiji Chemical): 0.5g of leuco crystal violet, 0.05g of malachite green, 0.8g of p-toluenesulfonamide, and 0.03g of 2,6-di-tert-butyl-4-methylphenol.

[0117] The solvent consists of the following components: 8g acetone, 10g toluene, and 5g methanol.

[0118] Preparation of photosensitive dry film

[0119] The preparation of a photosensitive dry film using the photosensitive resin compositions listed in Table 3 includes the following steps:

[0120] Using a coating experiment device (model: AB4220, TQC, Netherlands), the photosensitive composition paste prepared according to Table 3 was coated onto a 15μm thick polyethylene terephthalate (PET) support film. The solvent was removed by baking at 80℃ for 10 minutes. After baking, the thickness of the photosensitive layer was controlled at 30μm. Then, a polyethylene film (PE) was covered for protection to obtain a photosensitive dry film.

[0121] Preparation of resist patterned substrates

[0122] Substrates with resist patterns were prepared using the photosensitive compositions of Examples 3-8 of the present invention as shown in Table 3 and the photosensitive compositions of Comparative Examples 1-7, as follows:

[0123] (1) Photosensitive layer formation process: A photosensitive layer is formed on a substrate using a photosensitive composition;

[0124] (2) Exposure process: Irradiate a portion of the above photosensitive layer with active light to photocur the above area to form a cured area;

[0125] (3) Development process: Remove the portion of the photosensitive layer other than the cured area from the substrate and form a resist pattern on the substrate.

[0126] The operating conditions for each process are explained in detail below.

[0127] Photosensitive layer formation process: Using a copper-clad laminate with a 35μm thick rolled 1.2mm thick copper foil, after surface adjustment and preheating to 80°C, while peeling off the PE protective film of the photosensitive dry film obtained from each embodiment or comparative example, the above-mentioned photosensitive resin composition is laminated onto the copper-clad laminate using a hot roller laminator (Zhisheng Technology Co., Ltd., CSL-M25E) at a roller temperature of 110°C, an air pressure of 0.35MPa, and a lamination speed of 1.5m / min to obtain a test substrate.

[0128] Exposure process: Exposure is performed using a direct drawing exposure machine (Xinge Microelectronics, main wavelength 405nm), and the sensitivity is tested using a Stouffer 41-level step exposure scale, with the number of exposure frames controlled between 14 and 18.

[0129] Development Process: After exposure, the PET support film is peeled off. Using an alkaline developer (manufactured by Guangzhou Julong Printed Circuit Board Equipment Co., Ltd., a dry film developer), a 1wt% Na2CO3 aqueous solution at 30°C is sprayed for twice the minimum development time to dissolve and remove the unexposed portions of the photosensitive resin layer. After development, the substrate is rinsed with pure water for 1.5 times the development time, dehydrated using an air knife, and then dried with warm air to obtain a substrate with a cured film for evaluation. The minimum development time is the shortest time required for complete dissolution of the unexposed photosensitive resin layer.

[0130] Evaluation Project

[0131] 1. Sensitivity Evaluation

[0132] On the above-mentioned film-coated test substrate, a Stouffer 41-level stepped exposure scale was placed for photosensitivity testing. After the exposure process, the test substrate was left to stand for more than 20 minutes, then the PET film layer was peeled off, and a 1.0 wt% sodium carbonate aqueous solution was sprayed at 30°C to remove the unexposed resist layer. The development time was 2.0 times the minimum development time. After the above operation, a cured film obtained by curing the photosensitive resin composition was formed on the substrate surface. The exposure energy (mJ / cm) when the number of residual segments of the stepped exposure scale obtained by the cured film was 16. 2 The photosensitivity of the photosensitive resin composition was evaluated, with a smaller value indicating better photosensitivity.

[0133] 2. Resolution Evaluation

[0134] On the aforementioned test substrate after coating, photomask data with a wiring pattern of linewidth / spacing width of n:n (unit: μm) was used to expose the substrate at an energy level that ensured a residual stage number of 16 after development using a Stouffer 41-stage exposure ruler. After the development process, the resist pattern was observed using an optical microscope. The minimum linewidth at which a complete cured resist line was formed was used as the adhesion value to evaluate adhesion (μm). The smaller this value, the better the resolution.

[0135] 3. Evaluation of Dispersion Stability

[0136] The prepared photosensitive dry film was stored in the dark at 25°C for 2 weeks. The surface of the photosensitive layer was observed under a microscope and graded as follows:

[0137] ■ Indicates a uniform surface of the photosensitive layer;

[0138] × indicates undissolved material precipitated on the surface of the photosensitive layer.

[0139] 4. Transferability Evaluation

[0140] After preparing the three-layer photosensitive dry film as described above, the UV absorption spectrum of the dry film was detected using a UV spectrophotometer to obtain the absorbance A1 of the maximum absorption peak in the 350-450 nm range. The dry film was then placed at 30°C for 72 hours, and the PE film layer on the surface of the photosensitive dry film was removed. The UV absorption spectra of the PET layer and the photoresist layer were then detected using a UV spectrophotometer to obtain the absorbance A2 of the maximum absorption peak in the 350-450 nm range. If the sensitizer migrates to the PE layer surface, the absorbance of the maximum absorption peak in the 350-450 nm range of the PET layer and the photoresist layer will decrease; that is, the absorbance of the sensitizer that migrated to the PE layer is (A1-A2). The degree of photosensitizer migration is calculated, i.e., the migration rate A = (A1-A2) / A1. A larger value indicates a greater migration amount.

[0141] The basis for judgment is as follows:

[0142] ○: Mobility A < 0.01;

[0143] ×: Mobility A > 0.01.

[0144] The test results for evaluation items 1-4 are summarized in Table 4 below.

[0145] 5. Evaluation of developed precipitates

[0146] After drying, peel off the photosensitive resin layer and weigh 18g of the photosensitive layer resist, dissolving it in 1L of 1% Na2CO3 developing solution. Once the photosensitive layer is completely dissolved, pour the solution into a micro-developer and circulate it at 30℃ and 0.12MPa pressure for 60 minutes, then stop the circulation. Remove the circulated developing solution and let it stand for 72 hours. Then, filter the precipitate using ADVANTEC NO. 2 qualitative filter paper, dry it, and weigh it. Measure the weight of the precipitate on the filter paper as a percentage (w) of the initial 18g photosensitive layer. Specifically, ○ indicates 0 ≤ w ≤ 0.6%, △ indicates w is 0.6% < w ≤ 0.8%, and × indicates 0.8% < w.

[0147] The test results for evaluation items 1-5 are summarized in Table 4 below.

[0148]

[0149] The results in Table 4 show that, compared with the photosensitive resin compositions of Comparative Examples 1-7, the photosensitive resin compositions prepared by using photosensitizers TM1 and TM2 prepared in Examples 1 and 2 in Examples 3-8 of the present invention, while maintaining similar performance in terms of photosensitivity and resolution within the addition range of 0.1-1.0, exhibit significant advantages in performance such as dispersion stability, migration, and amount of developing debris; however, at addition amounts below 0.1 or above 1.0, the performance decreases significantly.

[0150] The above results demonstrate that the photosensitizer of the present invention has broad applicability, high photosensitivity and good formulation compatibility, and can greatly reduce development waste, exhibiting excellent formulation adaptability.

[0151] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Those skilled in the art can make various modifications and alterations within the spirit and principles of the present invention, and any modifications, equivalent substitutions, or improvements within this scope should be considered as covered by the protection scope of the present invention.

Claims

1. A photosensitive resin composition, based on 100 parts by weight of the photosensitive resin composition, comprising the following components: Alkali-soluble resin A: 50-65 parts; Photopolymerizable monomer B: 35-50 parts, which is selected from monomers containing olefinic unsaturated double bonds; Photoinitiator C: 2-5 parts, selected from diimidazole compounds; and Photosensitizer D: 0.1-1 part, in, The photosensitizer D is an anthracene-9-methylene sulfate monoquaternary ammonium salt having the structure shown in formula (I) and / or anthracene-9,10-dimethylene sulfate diquaternary ammonium salt having the structure shown in formula (II): Wherein, R in equation (I) a R b R c and R d and R in equation (II) e R f R g R h R o R p R q and R r Each is independently selected from hydrogen, C1-C6 alkyl, C6-C12 aryl-substituted C1-C6 alkyl, C3-C12 heteroaryl-substituted C1-C6 alkyl, and C1-C6 alkoxy-substituted C1-C6 alkyl; Wherein, R in equation (I) and equation (II) 1 R 2 R 3 R 4 R 5 R 6 R 7 R 8 and R 9 Each is independently selected from hydrogen, C1-C6 alkyl, C6-C12 aryl-substituted C1-C6 alkyl, C3-C12 heteroaryl-substituted C1-C6 alkyl, C1-C6 alkoxy-substituted C1-C6 alkyl, C3-C6 cycloalkyl and halogen; Optionally, in equation (I) R in part a R b R c and R d Any two of them form a 3-8 elemental ring with N; optionally, in equation (II) R in part e R f R g and R h Any two of them form a 3-8 elemental ring with N; and optionally, in equation (II) R in part o R p R q and R r Any two elements in the set form a 3-8 elemental ring with N in the set.

2. The photosensitive resin composition according to claim 1, wherein: R in equation (I) a R b R c and R d and R in equation (II) e R f R g R h R o R p R q and R r Each is independently selected from hydrogen and C1-C6 alkyl; R in formulas (I) and (II) 1 R 2 R 3 R 4 R 5 R 6 R 7 R 8 and R 9 Each is independently selected from hydrogen, C1-C6 alkyl, C3-C6 cycloalkyl, and halogen.

3. The photosensitive resin composition according to claim 1, wherein, Equation (I) has the following structure: Equation (II) has the following structure: 。 4. The photosensitive resin composition according to claim 1, wherein, The content of photosensitizer D is 0.1-0.8 parts by mass.

5. The photosensitive resin composition according to claim 1, wherein, The alkali-soluble resin A is an acrylate copolymer containing aromatic groups; based on the total mass of comonomers during the copolymerization process, the copolymerization ratio of comonomers with aromatic groups is 50-70%; the weight-average molecular weight of the alkali-soluble resin is 20,000-60,000, the resin acid value is 160-220 mg KOH / g, and the molecular weight distribution index is 1.0-3.

0. The photopolymerizable monomer B is selected from one or more of the following: methoxy polyethylene glycol monoacrylate, ethoxy(propoxy)nonylphenol acrylate, ethoxy(propoxy)bisphenol A di(meth)acrylate, ethoxy(propoxy)di(meth)acrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, ethoxy(propoxy)trimethylolpropane tri(meth)acrylate, di(trimethylolpropane)tetraacrylate, ethoxy(propoxy)pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol hexaacrylate.

6. The photosensitive resin composition according to claim 1, wherein, The diimidazole compound used as photoinitiator C is selected from 2,4,5-triarylimidazolium dimers.

7. The photosensitive resin composition according to claim 1, wherein, The bisimidazole compound is selected from one or more of 2-(2-chlorophenyl)-4,5-diphenylimidazolium dimer, 2-(2-chlorophenyl)-4,5-di(methoxyphenyl)imidazolium dimer, 2-(2-fluorophenyl)-4,5-diphenylimidazolium dimer, 2-(2-methoxyphenyl)-4,5-diphenylimidazolium dimer, 2-(4-methoxyphenyl)-4,5-diphenylimidazolium dimer, and 2,2',4-tris(2-chlorophenyl)-5-(3,4-dimethoxyphenyl)-4',5'-diphenyl-1,1'-diimidazole.

8. The photosensitive resin composition according to claim 1, wherein, The photosensitive resin composition further comprises one or more additives E selected from dyes, photodevelopers, plasticizers, adhesion promoters, polymerization inhibitors, defoamers, and coating aids; the total amount of additives E is 0.5-5.0 parts by weight.

9. A photosensitive dry film, said photosensitive dry film comprising, from bottom to top: Support layer; A photosensitive resist layer attached to the surface of the support layer; and A protective layer adhering to the surface of the photoresist layer. The photosensitive resist layer is formed using the photosensitive resin composition according to any one of claims 1 to 8.

10. The application of the photosensitive dry film of claim 9 in printed circuit boards, lead frames, semiconductor packaging substrates, solar cells, and photocurable inks.

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