Photosensitive resin composition, photosensitive dry film, and method for producing the same

Abstract

The application provides a photosensitive resin composition, a photosensitive dry film and a preparation method thereof. The photosensitive resin composition comprises an alkali-soluble resin, a photopolymerization monomer, a photoinitiator, a sensitizer and an additive; wherein the sensitizer comprises a compound with a structure shown in a general formula (I), wherein A is R0 selected from a linear or branched alkylene group with 2-12 carbon atoms; R' is selected from H, halogen, a nitro group, a linear or branched alkyl group with 1-8 carbon atoms, a linear or branched alkoxy group with 1-4 carbon atoms and an aryl group with 6-18 carbon atoms; and n is an integer with 1-100. By introducing a specific photosensitive unit structure into a conventional anthracene sensitizer, the photosensitivity is increased, and the photosensitive resin composition obtained by matching suitable alkali-soluble resins, photopolymerization monomers and other components meets the application requirements of high resolution, high adhesion and high thickness for high-precision IC carrier board and special scene use.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor, in particular to a photosensitive resin composition, its preparation method and application. BACKGROUND

[0002] The photosensitive resin composition is widely used as etching or plating resist material in the manufacturing process of printed circuit board (PCB), lead frame (LF) and semiconductor packaging (IC) substrate. Among them, the photosensitive resin composition is usually coated on the surface of PET support film, and after drying, a protective layer such as polyethylene film (PE) protective layer is closely attached to the surface, also known as photosensitive dry film, dry film resist and the like. The semiconductor packaging substrate is a key special material in the packaging process. The semiconductor packaging substrate (IC carrier board for short) can be understood as a high-end printed circuit board, which has the characteristics of high density, high precision, high performance, miniaturization and thinning, etc., and its main function is to carry chips as a carrier, which is the physical connection between chips and conventional PCB, and plays the role of providing electrical conduction, signal distribution, power distribution, and communication between internal and external circuits of the chip, while providing protection, fixation, support, heat dissipation and standard mounting size for the chip, so as to realize multi-pin, miniaturization of packaging products, improve electrical performance or multi-chip modularization, etc.

[0003] With the development trend of electronic devices towards lighter and thinner, the market also further requires the lines of PCB to be more fine and high-density. The semi-additive process (SAP) is the mainstream manufacturing method for forming fine wiring PCB, especially IC carrier board. The semi-additive process (SAP) directly forms a resist pattern on thin copper, then increases the thickness of the conductor copper through pattern plating, and then removes the resist pattern, and then quickly etches to remove the exposed bare copper to form a line, which can effectively produce fine lines with a line width and spacing of 25 μm or less. The traditional photo mask exposure method consumes a large amount of film, has high production cost, and the line pattern precision obtained by this method is limited, so it is gradually being replaced by laser direct imaging (LDI), which does not require film and uses digital data to directly irradiate active light images. With the development of printed circuit board technology and semiconductor packaging technology, electronic circuits are developing towards high density and miniaturization. Laser direct imaging (LDI) technology has been increasingly widely used due to its high positioning accuracy and fast production efficiency. i-ray (355 nm) or h-ray (405 nm) is used as the light source. Wavelength of 405 nm laser is commonly used, which has better exposure precision and can form high-density photosensitive resist patterns that are difficult to produce by previous technologies.

[0004] For the photosensitive resin composition for IC carrier, in order to improve its resolution, it is necessary to add a suitable photosensitizer in the photosensitive resin composition. For the photosensitive resin composition, the suitable photoinitiating system has a direct influence on photosensitivity, resolution, production yield. And anthracene compounds or anthracene derivatives are widely used in high-resolution LDI photosensitive resist due to their good photosensitivity and resolution. For example, alkoxyl or aryl substituted anthracene compounds are often added as sensitizers in photosensitive resin compositions for packaging carrier boards. For example, patent CN101568883B discloses a photosensitive resin composition containing benzene alkali-soluble resin and 9,10-dibutoxy anthracene sensitizer, which has high photosensitivity and resolution.

[0005] Due to the adverse effect of light scattering on the resolution performance of dry film resist, the resolution capacity of dry film resist will be significantly reduced with the increase of thickness. The resolution capacity of traditional dry film resist is generally 0.8-1.0 times the thickness of the dry film resist, while the carrier board and the like require the resolution capacity of the dry film resist to be less than 0.5 times the thickness of the film. The film thickness of the dry film resist used for the production of carrier boards and the like is generally 20-29μm, and the resolution capacity is required to be less than 15μm, and the 10μm / 10μm line process has been put on the agenda, and in the near future, the line precision of IC carrier board will reach 5μm / 5μm. For the dry film resist, it is required to meet the high precision and high aspect ratio of IC carrier board, and it is also required to have good photosensitivity to improve the industrial production efficiency. For some high-resolution, high-attachment and high-thickness dry film resists used in special scenes, the film thickness is generally ≥60μm, and the resolution and attachment capacity is required to be ≤30μm, and the aspect ratio and precision of the resist are more demanding.

[0006] To meet the above-mentioned demanding performance requirements, it is particularly important to select a suitable photoinitiator and sensitizer system for each component of the dry film resist. At present, the initiator system used in the dry film resist for the production of carrier boards and the like is generally a hexaarylbiimidazole derivative combined with an anthracene (DBA) sensitizer.

[0007] However, from the results of the examples in the above-mentioned patent, the photosensitivity is still low, even if the exposure energy reaches 50mJ / cm 2 , the sensitivity of the dry film resist is only 11. Moreover, the present inventors have found that:

[0008] Firstly, alkoxy-substituted anthracene compounds such as 9, 10-diethoxyanthracene and / or 9, 10-dibutoxyanthracene have low photosensitivity under a laser light source with a wavelength of 405 nm. To improve the photosensitivity of the resist and reduce the exposure energy, the amount of such photosensitizers is generally increased. However, due to the poor solubility of such photosensitizers, the dissolution rate is slow during the dissolution of the glue solution, which affects the production efficiency or causes unevenness due to insufficient dissolution. Because of the large amount of use of such photosensitive agents with poor water solubility, insoluble substances are easy to accumulate and produce precipitates in the developer during use by downstream customers. These precipitates are easy to adsorb on the surface of the substrate after development. The adsorbed garbage on the copper surface forms an obstruction during the etching process after the substrate is developed, resulting in incomplete etching of the copper surface that should have been etched, causing copper residue or short circuit and other defects.

[0009] Secondly, dry film resists are usually coated on the surface of a PET support film, and a protective layer such as a polyethylene film protective layer is tightly attached to the surface after drying, as described in patent CN113557474A. When 9, 10-dibutoxyanthracene (DBA) is contained in the dry film resist, it will inevitably have a tendency to penetrate and precipitate as crystals in the polyethylene film. This penetration problem is particularly evident when the protective layer is a polyethylene film. The penetration and precipitation phenomenon may cause short circuit, open circuit and other defects in the resist pattern, thereby reducing the yield of the product. At the same time, such compounds are easy to penetrate and precipitate from the polyethylene film (PE), which also poses a risk of photosensitivity decline due to the penetration of the photosensitizer from the photosensitive layer.

[0010] Thirdly, photosensitive resin compositions applied to IC substrates, as described in patent CN101568883B, generally use alkali-soluble resins with high styrene content to improve resolution and adhesion. However, due to the high rigidity of styrene, photosensitive resin compositions with such alkali-soluble resins as the main component generally have the disadvantage of being hard and brittle. Such hard and brittle film materials may cause open gaps due to the spraying pressure of the developer during use by customers, resulting in a significant decrease in yield.

[0011] In addition, for some dry film resists used in special scenarios, such as mSAP electroplating processes that require thick copper plating and fine lines, and long copper pillar processes in the semiconductor industry. Such special application processes require dry film resists with a film thickness significantly greater than conventional dry film resists (film thickness ≥ 60 μm) and excellent resolution and window opening ability, adhesion. In addition, as the film thickness and exposure level increase, the flexibility of the resist film material decreases rapidly. Therefore, to improve the yield of customers, high-resolution high-thickness dry film resists must also have good flexibility.

[0012] The photosensitizer of anthracene has the characteristics of photobleaching, which makes the light source reach the bottom of the resist to a high degree during the exposure process of the dry film resist, even in high thickness resist systems, increases the degree of polymerization at the bottom of the resist, and finally obtains a pattern with excellent resist side edge morphology and good straight depth ratio after development. Therefore, the photosensitive resin composition system containing 9,10-dibutoxy anthracene sensitizer for IC board manufacturing is also widely used in high resolution, high adhesion, high thickness dry film resist for special scenes.

[0013] However, due to the problems of poor solubility, insufficient photosensitivity, easy deposition during development, easy penetration to the protective layer, poor flexibility and the like, the photosensitive resin composition system commonly used for IC board manufacturing is difficult to meet the performance indicators of high resolution, high adhesion, high thickness dry film resist for special scenes.

[0014] It is difficult for a dry film resist to have high film thickness, high resolution, high adhesion and high flexibility at the same time, because these properties themselves have certain contradictions and will restrict each other. It is necessary to solve the contradiction between high thickness and high resolution, high adhesion, and to solve the contradiction between high film thickness, high resolution, high adhesion and flexibility. The performance requirements of the initiator system and the alkali-soluble resin of the main component of the dry film resist are also very high.

[0015] In order to improve the resolution and adhesion of the dry film resist, Hitachi patent CN101568883 discloses a photosensitive resin composition with high aryl content alkali-soluble resin and 9,10-dibutoxy anthracene sensitizer. However, from the example results, the photosensitivity of the resist is still poor with the addition of a higher content of 9,10-dibutoxy anthracene sensitizer, the sensitivity is only 11 / 41ST and the resolution is only 10 μm at 50 mj exposure. In order to improve the production efficiency of the client and the precision of the production board, the photosensitivity and resolution need to be further improved. In addition, some key performances, such as development, photosensitivity decline due to initiator migration, flexibility, whether it can be used for high resolution, high adhesion, high thickness dry film resist for some special scenes, and some key performances, are not mentioned in this patent.

[0016] In summary, the photosensitive resin composition in the prior art cannot meet the resolution precision performance requirements of the dry film resist for board manufacturing process, and cannot meet the key performance of high resolution, high adhesion, high thickness dry film resist for some special scenes, and needs to be further optimized. SUMMARY

[0017] The main purpose of the present application is to provide a photosensitive resin composition, a photosensitive dry film and a preparation method thereof, to solve the problems of poor photosensitivity, resolution, adhesion and poor flexibility of the photosensitive resin in the prior art, which leads to the inability to balance high sensitivity, high resolution, high adhesion, high thickness and high flexibility. In addition, it is particularly important that in the prior art, the sensitizer is prone to migrate to the protective film and is prone to develop and deposit, which leads to continuous decay of the sensitivity of the photosensitive resin during storage and use, and the stability and yield of the obtained photosensitive resin pattern are poor.

[0018] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a photosensitive resin composition is provided, comprising an alkali-soluble resin, a photopolymerization monomer, a photoinitiator, a sensitizer and an additive; wherein the sensitizer comprises a compound having the structure shown in general formula (I):

[0019]

[0020] wherein A is R0 is selected from C2-C12 linear or branched alkylene; R' is selected from H, halogen, nitro, C1-C8 linear or branched alkyl, C1-C4 linear or branched alkoxy, C6-C18 aryl; n is an integer of 1-100.

[0021] Further, in general formula (I), R0 is selected from CH2CH2-, CH2CH(CH3)-, -(CH2)4, -(CH2)6; and / or R' is selected from H, Cl, Br, nitro, C1-C8 linear or branched alkyl, C1-C4 linear or branched alkoxy, C6-C18 aryl; and / or n is an integer of 1-100; and / or the molecular weight of the sensitizer is 600-6000, preferably 700-4000.

[0022] Further, the alkali-soluble resin comprises a copolymer having the structure shown in general formula (II):

[0023]

[0024] R1, R2, R3, R4are independently selected from H, methyl; R5is selected from C1-C5 linear or branched alkyl, C1-C5 linear or branched alkoxy, hydroxyl, halogen; R6is selected from C1-C10 linear or branched alkylene; R is selected from C5-C14 substituted or unsubstituted monocyclic carbocycloalkyl, C5-C14 substituted or unsubstituted bicyclic carbocycloalkyl, C5-C14 substituted or unsubstituted polycyclic carbocycloalkyl, C5-C14 substituted or unsubstituted monocyclic heterocycloalkyl, C5-C14 substituted or unsubstituted bicyclic heterocycloalkyl, C5-C14 substituted or unsubstituted polycyclic heterocycloalkyl, and the bicyclic carbocycloalkyl and polycyclic carbocycloalkyl independently have fused or bridged ring structure; R" is selected from C1-C18 linear or branched alkyl; X is an integer from 0 to 5; Y is an integer from 0 to 5; a1, b1, c1, d1 are the weight percentages of each structural unit in the alkali-soluble resin, a1 is 18-35 wt%, b1 is 0-60 wt%, c1 is 0-80 wt%, d1 is 0-15 wt%.

[0025] Further, in general formula (II), R5is selected from methyl, methoxy, hydroxyl, halogen; and / or R6is selected from methyl, ethyl, propyl; and / or R is selected from 1-adamantyl, dicyclopentyl, cyclohexyl, isobornyl; and / or R" is selected from methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, isooctyl; and / or X is an integer from 0 to 2; and / or Y is an integer from 0 to 5; and / or a1 is 20-30 wt%, b1 is 20-40 wt%, c1 is 20-50 wt%, d1 is 3-10 wt%.

[0026] Further, the alkali-soluble resin has an acid value of 120-250 mg KOH / g, a weight average molecular weight of 25000-60000, a molecular weight distribution of 1.3-2.5, and a polymerization conversion rate of ≥97%.

[0027] Further, the alkali-soluble resin contains an alicyclic alkane (meth)acrylate structural unit, and the raw material includes one or more of 1-adamantyl (meth)acrylate, 2-adamantyl (meth)acrylate, (meth)acrylic acid tricyclo[5.2.1.02,6]dec-8-yl ester, 2-methyl-2-adamantanol acrylate, 2-ethyl-2-adamantanol acrylate, 2-carboxy-4-norbornolactone-5-methacrylate, 2-isopropyl-2-adamantanol (meth)acrylate, isobornyl acrylate, acryloyl morpholine, 1-adamantyl methyl acrylate, 3-hydroxy-1-adamantyl (meth)acrylate, cyclohexane dicarboximide acrylate, cyclohexyl methacrylate, 5-oxotetrahydrofuran-3-yl methacrylate, 5-carboxy-2-tetrahydrofurfuryl alcohol-methacrylate, 1-ethylcyclopentyl methacrylate, 1-isopropyl-1-cyclohexanol methacrylate, 2-cyclohexyl-2-propanol methacrylate, 2-ketotetrahydrofuran-3-hydroxy-methacrylate, methylcyclopentyl acrylate, 1-ethylcyclopentyl acrylate, 2-oxotetrahydrofuran-3-yl acrylate, cyclohexyl (meth)acrylate, 1-methyl-1-cyclohexyl methacrylate, 1-methylcyclopentyl methacrylate, 1-ethylcyclohexyl methacrylate, 1-methyl-1-ethyl-1-adamantyl methacrylate, 2-tetrahydrofuryl methacrylate, 2-methyl acrylate-4-hydroxy pyran, dicyclopentyl methacrylate; and / or

[0028] The alkali-soluble resin contains a benzyl ester and / or phenoxyethyl ester (meth)acrylate structural unit, and the raw material includes one or more of benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, o-phenylphenoxyethyl acrylate; and / or the alkali-soluble resin contains a linear or branched (meth)acrylate structural unit, and the raw material includes one or more of methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, isooctyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate.

[0029] Further, the photosensitive resin composition includes 45 to 65 parts by weight of the alkali-soluble resin, 30 to 50 parts by weight of the photopolymerization monomer, 2.0 to 5.0 parts by weight of the photoinitiator, 0.03 to 2.0 parts by weight of the sensitizer, and 0.5 to 5 parts by weight of the additive.

[0030] Further, the photoinitiator includes a hexaarylbiimidazole derivative, and the hexaarylbiimidazole derivative has a structure represented by general formula (III):

[0031]

[0032] A1, A2, A3, A4, A5, A6 are independently selected from H, methoxy, halogen atom.

[0033] Further, the photoinitiator includes one or more of 2-(o-chlorophenyl)-4,5-diphenyl imidazole dimer, 2-(o-chlorophenyl)-4,5-di(methoxyphenyl) imidazole dimer, 2-(o-fluorophenyl)-4,5-diphenyl imidazole dimer, 2-(o-methoxyphenyl)-4,5-diphenyl imidazole dimer, 2-(p-methoxyphenyl)-4,5-diphenyl imidazole dimer, 2,2',4-tris(2-chlorophenyl)-5-(3,4-dimethoxyphenyl)-4',5'-diphenyl-1,1'-biimidazole.

[0034] Further, the photopolymerization monomer includes one or more of monofunctional (meth)acrylate type olefinically unsaturated double bond monomer, difunctional (meth)acrylate type olefinically unsaturated double bond monomer, multifunctional (meth)acrylate type olefinically unsaturated double bond monomer; preferably, the photopolymerization monomer includes one or more of lauryl (meth)acrylate, stearyl (meth)acrylate, nonyl phenol acrylate, isobornyl acrylate, tetrahydrofurfuryl acrylate, bisphenol A di(meth)acrylate, polyethylene glycol (propylene glycol) di(meth)acrylate, ethoxylated (propoxylated) neopentyl glycol diacrylate, trimethylolpropane tri(meth)acrylate, ethoxylated (propoxylated) trimethylolpropane tri(meth)acrylate, ethoxylated (propoxylated) pentaerythritol triacrylate, ethoxylated (propoxylated) pentaerythritol tetraacrylate, ethoxylated (propoxylated) dipentaerythritol pentaacrylate, ethoxylated (propoxylated) dipentaerythritol hexaacrylate.

[0035] Further, the photopolymerization monomer includes at least one of compounds having a structure shown in general formula (IV), general formula (V) or general formula (VI), wherein the EO repeating unit and the PO repeating unit are randomly arranged or block arranged:

[0036]

[0037] R a is selected from H or CH3; the EO repeating unit and the PO repeating unit account for 20-80 wt% of the photopolymerization monomer; m1, m2 are respectively integers of 1-20, n1, n2 are respectively integers of 0-20, and m1+m2 is an integer of 2-20, n1+n2 is an integer of 0-20;

[0038]

[0039] R b is H or CH3; a2 is an integer of 4-20, b2 is an integer of 0-20;

[0040]

[0041] R c H or CH3; a3 is an integer of 3 to 20, b3 is an integer of 0 to 20, and c3 is an integer of 3 to 20.

[0042] Further, the additive includes one or more of a radical polymerization inhibitor, a dyeing agent, a hidden dyeing agent, a plasticizer, a photothermal stabilizer, an adhesion promoter, a leveling agent, and a defoaming agent; preferably, the radical polymerization inhibitor includes one or more of p-methoxyphenol, 4-ethyl-6-tert-butylphenol, tert-butyl catechol, 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl, nitrosophenyl hydroxylamine aluminum salt, 2-methyl catechol, 3-methyl catechol, 4-methyl catechol, catechol, 2-ethyl catechol, 3-ethyl catechol, 4-ethyl catechol, 2-propyl catechol, 3-propyl catechol, 4-propyl catechol, 2-n-butyl catechol, 3-n-butyl catechol, 4-n-butyl catechol, 2-tert-butyl catechol, 3-tert-butyl catechol, 4-tert-butyl catechol, 3,5-di-tert-butyl catechol, resorcinol, 2-methyl resorcinol, 4-methyl resorcinol, 5-methyl resorcinol, 2-ethyl resorcinol, 4-ethyl resorcinol, 2-propyl resorcinol, 4-propyl resorcinol, 2-n-butyl resorcinol, 4-n-butyl resorcinol, 2-tert-butyl resorcinol, 4-tert-butyl resorcinol, 1,4-hydroquinone, methylhydroquinone, ethylhydroquinone, propylhydroquinone, tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, 2,6-di-tert-butyl-4-methylphenol, pyrogallol, 2,2-methylenebis(4-methyl-6-tert-butylphenol); more preferably, the radical polymerization inhibitor includes one or more of p-methoxyphenol, 4-ethyl-6-tert-butylphenol, tert-butyl catechol, 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl, nitrosophenyl hydroxylamine aluminum salt; more preferably, the weight part of the radical polymerization inhibitor is 0.001 to 0.03 parts.

[0043] According to another aspect of the present application, there is provided a photosensitive dry film including a support film, a dry film resist layer, and an optional protective layer, the raw material of the dry film resist layer including the photosensitive resin composition described above in the present application.

[0044] According to another aspect of the present application, a method for preparing the photosensitive dry film is provided, comprising the following steps: S1, mixing an alkali-soluble resin, a photopolymerization monomer, a photoinitiator, a sensitizer, a free radical polymerization inhibitor and a solvent to obtain a resin composition solution; S2, coating the resin composition solution on the surface of a PET support film after standing for 25-35 min, and drying to form a dry film resist layer; and S3, adhering a polyethylene film protective layer to the surface of the dry film resist layer to obtain a photosensitive dry film.

[0045] Further, the solvent comprises one or more of acetone, butanone, methanol, ethanol, isopropanol and toluene; and / or the solid content of the resin composition solution is 35-45%; and / or the drying temperature is 80-100 DEG C and the time is 5-15 min; and / or the thickness of the dry film resist layer is 15-300 mu m.

[0046] By modifying the molecular structure of the conventional anthracene sensitizer, introducing a specific photosensitive unit structure to increase photosensitivity, increasing the molecular weight and reducing the migration of the anthracene sensitizer, the technical solution of the present application can increase water solubility and improve the development and precipitation phenomenon. The high photosensitivity and low migration sensitizer compound system after optimization and modification is used in the present application, and appropriate alkali-soluble resin, photopolymerization monomer and other components are matched to obtain a photosensitive resin composition, which has high photosensitivity, high resolution, and stable sensitivity, resist pattern and other aspects of performance, and meets the application requirements of high resolution, high adhesion and high thickness for high-precision IC carrier board and special scene use. BRIEF DESCRIPTION OF DRAWINGS

[0047] The drawings accompanying the specification of the present application serve to provide further understanding of the present application, and the illustrative embodiments of the present application and the description thereof serve to explain the present application, and do not constitute improper limitations on the present application. In the drawings:

[0048] Figure 1 An electron microscope photograph showing a film thickness of 25 mu m and an independent adhesion of 8 mu m according to an embodiment of the present application is shown;

[0049] Figure 2 An electron microscope photograph showing a film thickness of 90 mu m and a resolution of 22 mu m according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0050] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0051] Unless otherwise specified, the "*" in the present application refers to the position of the chemical bond connection.

[0052] As described in the background of the invention, the prior art exists in the problem that the photosensitive resin cannot simultaneously consider high resolution, high adhesion, high thickness, high flexibility, and the sensitizer is easy to migrate, resulting in poor stability and yield of the photosensitive resin pattern. In order to solve the above problems, in a typical embodiment of the present application, a photosensitive resin composition is provided, comprising alkali-soluble resin, photopolymerization monomer, photoinitiator, sensitizer and additive; wherein the sensitizer comprises a compound having the structure shown in general formula (I):

[0053]

[0054] wherein A is R0 is selected from C2-C12 straight chain or branched alkylene; R' is selected from H, halogen, nitro, C1-C8 straight chain or branched alkyl, C1-C4 straight chain or branched alkoxy, C6-C18 aryl; n is an integer of 1-100.

[0055] wherein the alkoxy long chain containing R0 is located on the 1, 4 to 10 carbon of A (anthracene ring) shown in the structure of general formula (I):

[0056]

[0057]

Sensitizer

[0058] The sensitizer of the present application is modified with an alkoxy long chain based on conventional anthracene sensitizers. Firstly, the modified sensitizer molecule contains both thioxanthone and anthracene structural units, and the spectral absorption spectrum has two peaks corresponding to thioxanthone (peak value at 380-400 nm) and anthracene (peak value at 420-440 nm), and each sensitizer molecule contains two thioxanthone anthracene structural units. Therefore, compared with conventional anthracene sensitizers such as DBA, the photosensitivity of the sensitizer molecules of the present application is stronger under a laser light source with a wavelength of 405 nm.

[0059] Secondly, the modified sensitizer molecule of the present application retains the structure of anthracene, and during exposure, the anthracene with longer wavelength can be photobleached to achieve better deep curing. Therefore, the modified sensitizer also has excellent deep curing ability, and the resist pattern after exposure can achieve a very high aspect ratio (depth to width ratio) (such as 2:1-3:1), which can be used for high-precision IC carrier board and other high-order PCB manufacturing, and can also consider the requirements of high resolution and high thickness.

[0060] Thirdly, since anthracene is a rigid aromatic ring structure, the solubility of conventional anthracene sensitizers in the photosensitive resin glue system and the developing aqueous solution system is poor. In order to improve photosensitivity, aromatic ring coupled anthracene (such as 9,10-diphenyl anthracene) can be used. Although this kind of sensitizer can significantly improve photosensitivity, the solubility of this kind of sensitizer with high aromatic ring structure in the above-mentioned solution system will further decrease. The alkoxy long chain modified sensitizer shown in general formula (I) can effectively improve the solubility of anthracene sensitizers in the photosensitive resin glue system and the developing aqueous solution system, increase the uniformity of the glue, improve the development precipitation problem, and improve the production yield and production efficiency of the resist manufacturer and downstream manufacturers.

[0061] The sensitizer shown in general formula (I) can be prepared by reacting alcohol with conventional anthracene sensitizer raw materials. Preferably, the alcohol is dihydric alcohol, and by using alcohol with different chain lengths, alkoxy long chain modified double functional sensitizers with sulfur anthracene and anthracene structures of different target molecular weights can be synthesized.

[0062] Specifically, the anthracene sensitizer raw material has a structure shown in general formula (a): wherein A and R' have the same definition as general formula (I), the substituent containing R' is located on the 1, 4 to 10 carbon of A (anthracene ring) shown in general formula (a), and the above-mentioned anthracene sensitizer raw material can be conveniently purchased from the market.

[0063] Specifically, the preparation method of the sensitizer shown in general formula (I) comprises the following steps: mixing the anthracene sensitizer raw material with alcohol, catalyst and solvent, first reacting at 0°C for 25-35 min, then reacting at 20-30°C for 1.5-2.5 h, and finally reacting at 75-85°C for 10-14 h; preferably, the alcohol includes ethylene glycol, the catalyst includes triethylamine, and the solvent includes acetonitrile; more preferably, the molar ratio of the anthracene sensitizer raw material to alcohol is (2-3):1, and the molar ratio of alcohol to catalyst is 1:(2.5-3.5).

[0064] In addition, the alkoxy long chain modified double functional sensitizer with sulfur anthracene and anthracene structure shown in general formula (I) only needs to contain sulfur anthracene and anthracene structure, and each molecule contains 2 sensitizer structure units (double functionality), which can achieve the same effect of considering high photosensitivity and low migration, the specific structure form and atomic order of the "alkoxy long chain" connecting the two sensitizer structure units can be properly adjusted, the "alkoxy long chain" can also be replaced by other alkyl, alkoxy, nitrogen-containing alkyl and other groups, and can also contain heteroatoms such as sulfur atoms.

[0065] The present application introduces specific photosensitive unit structure to increase photosensitivity, improve molecular weight, reduce migration of anthracene sensitizer by modifying the molecular structure of conventional anthracene sensitizer; at the same time, water solubility can be increased and development and precipitation phenomenon can be improved. The high photosensitivity and low migration sensitizer compound system after optimization and modification is used, and suitable alkali-soluble resin, photopolymerization monomer and other components are matched, so that a good photosensitive resin composition (dry film resist) can be obtained, which has high photosensitivity, high resolution, and stable sensitivity, resist pattern and other aspects of performance, and meets the application requirements of high resolution, high adhesion and high thickness for high-precision IC carrier and special scene use.

[0066] In order to further increase photosensitivity, improve molecular weight, reduce migration of anthracene sensitizer; at the same time, increase water solubility and improve development and precipitation phenomenon, in a preferred embodiment, in the general formula (I), R0 is selected from CH2CH2-, CH2CH(CH3)-, -(CH2)4, -(CH2)6; and / or R' is selected from H, Cl, Br, nitro, C1-C8 linear or branched alkyl, C1-C4 linear or branched alkoxy, C6-C18 aryl; and / or n is an integer of 1-100.

[0067] The inventors unexpectedly found in the research process that increasing the molecular weight of the sensitizer is an important way to control the migration of the sensitizer. The sensitizer with a molecular weight of 200-250 will migrate quickly, the sensitizer with a molecular weight of 300-400 will have a more obvious migration phenomenon, and the molecular weight of the conventional anthracene sensitizer DBA is only 322, which inevitably has the problem of sensitizer migration. In a preferred embodiment, the molecular weight of the sensitizer is 600-6000, preferably 700-4000. The present application modifies the anthracene sensitizer with alkoxy long chain, increases the molecular weight of the sensitizer to 600-6000, preferably 700-4000, which can fundamentally solve the problem of sensitizer migration, and can well balance the photosensitivity of the sensitizer, and can make the photosensitive resin composition have long-term stable photosensitivity.

[0068]

Alkali-soluble resin

[0069] In a preferred embodiment, the alkali-soluble resin includes a copolymer having a structure shown in general formula (II):

[0070]

[0071] R1, R2, R3, R4are independently selected from H, methyl; R5is selected from C1-C5 linear or branched alkyl, C1-C5 linear or branched alkoxy, hydroxyl, halogen; R6is selected from C1-C10 linear or branched alkylene; R is selected from C5-C14 substituted or unsubstituted monocyclic carbocyclic alkyl, C5-C14 substituted or unsubstituted bicyclic carbocyclic alkyl, C5-C14 substituted or unsubstituted polycyclic carbocyclic alkyl, C5-C14 substituted or unsubstituted monocyclic heterocyclic alkyl, C5-C14 substituted or unsubstituted bicyclic heterocyclic alkyl, C5-C14 substituted or unsubstituted polycyclic heterocyclic alkyl, and the bicyclic carbocyclic alkyl and polycyclic carbocyclic alkyl independently have fused or bridged ring structure; R" is selected from C1-C18 linear or branched alkyl; X is an integer from 0 to 5; Y is an integer from 0 to 5; a1, b1, c1, d1 are the weight percentages of each structural unit in the alkali-soluble resin, a1 is 18-35 wt%, b1 is 0-60 wt%, c1 is 0-80 wt%, d1 is 0-15 wt%.

[0072] In the structure of the alkali-soluble resin used in the conventional high adhesion photosensitive resin composition, a relatively high proportion of styrene structural units is contained, and the benzene ring of the styrene is directly connected to the main chain of the macromolecule. The single bond connecting the benzene ring and the main chain has low rotational freedom, resulting in high rigidity of the alkali-soluble resin. The photosensitive resist using the alkali-soluble resin as the main material has extremely poor flexibility.

[0073] In the structure of the alkali-soluble copolymer resin as shown in general formula (II), no styrene structural units are contained, and the aliphatic ring is directly connected to the main chain of the macromolecule. In the aliphatic ring, mainly composed of C-C single bonds, the electron cloud distribution of the σ bond has axial symmetry. Therefore, the two carbon atoms connected by the σ bond can rotate relative to each other without affecting the distribution of the electron cloud. At the same time, due to the restriction of the ring, the rotational freedom of the C-C single bond in the aliphatic ring is smaller than that of the conventional linear or branched alkyl, but it is obviously larger than that of the benzene ring or aromatic ring containing a π conjugated system. That is, the flexible group containing the aliphatic ring macromolecular chain is between the alkyl and aromatic ring, which can better balance the flexibility and mechanical properties.

[0074] On the other hand, the copolymer resin structure as shown in general formula (II) also contains copolymerization units with aromatic ring structure, but in copolymerization structural units such as benzyl (meth) acrylate and phenoxyethyl (meth) acrylate, the aromatic ring such as benzene ring is not directly connected to the main chain of the macromolecule, but is connected to the main chain of the macromolecule through a flexible segment composed of one or more C-C or C-O single bonds. Such soft and hard phase separation chemical structure can not only maintain the rigidity and strength of the aromatic ring, but also increase part of the flexibility and toughness.

[0075] Specifically, the preparation method of the alkali-soluble copolymer resin shown in general formula (II) comprises the following steps: mixing monomers corresponding to a1, b1, c1, and d1 respectively according to weight ratio to obtain a mixed monomer, then mixing the mixed monomer with a photoinitiator and a solvent to obtain a mixed solution; dividing the mixed solution into two parts, i.e., a first part of the mixed solution and a second part of the mixed solution, and the mass ratio of the two is (30-40):(60-70); reacting the first part of the mixed solution at 75-85°C for 0.5-1.5h, then adding the second part of the mixed solution and completing the addition within 2.5-3.5h to obtain a reaction solution; first reacting the reaction solution at 75-85°C for 3.5-4.5h, then reacting at 85-95°C for 2-3h, at this time, 5g of butanone solution containing 0.2g of initiator can be added twice with an interval of 1h; and obtaining the alkali-soluble resin. Preferably, the photoinitiator comprises AIBN photoinitiator; the solvent comprises butanone and ethanol, and the mass ratio of the two is (5.5-6.5):1; preferably, the mass ratio of the mixed monomer to the photoinitiator is 100:(0.8-1.5); and the mass ratio of the mixed monomer to the solvent is 100:(100-110).

[0076] In summary, the alkali-soluble copolymer resin shown in general formula (II) can well balance the flexibility and mechanical properties in structure, and the photosensitive resin composition using the alkali-soluble copolymer resin as a main material can have excellent adhesion and good flexibility, and the customer can significantly reduce the phenomenon of disconnection, notch, plating, short circuit and other defects, and the yield can be significantly improved. Through structural modification of the alkali-soluble resin, the present application introduces specific groups to improve the flexibility and adhesion of the alkali-soluble resin, which can further improve the photosensitivity, resolution, sensitivity, and other properties of the resin composition, thereby better meeting the application requirements of high resolution, high adhesion, high thickness, and high flexibility.

[0077] In order to better balance high resolution, high adhesion, high thickness, high flexibility when the photosensitive resin composition is used for high-precision IC carrier board and other high-order PCB manufacturing and special scene, in a preferred embodiment, in general formula (II), R5 is selected from methyl, methoxy, hydroxyl, halogen, etc.; and / or R6 is selected from methyl, ethyl, propyl; and / or R is selected from 1-adamantyl, dicyclopentyl, cyclohexyl, isobornyl, etc.; and / or R” is selected from methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, isooctyl, etc.; and / or X is an integer of 0-2; and / or Y is an integer of 0-5; and / or a1 is 20-30wt%, b1 is 20-40wt%, c1 is 20-50wt%, and d1 is 3-10wt%. Thus, the flexibility and adhesion of the alkali-soluble resin are further improved.

[0078] The inventors unexpectedly found that when the alkali-soluble copolymer resin has an acid value less than 120 mg KOH / g, there is a tendency for poor alkali solubility, long development and stripping time, and when the acid value exceeds 250 mg KOH / g, there is a tendency for poor resolution. Meanwhile, the alkali-soluble copolymer resin has a narrow molecular weight distribution, which is beneficial to improving the resolution of the photosensitive resin composition, and when the molecular weight distribution is greater than 2.5, there is also a tendency for poor resolution. Therefore, the present application is limited in a preferred embodiment, the acid value of the alkali-soluble resin is 120-250 mg KOH / g, the weight average molecular weight is 25000-60000, the molecular weight distribution is 1.3-2.5, and the polymerization conversion rate is ≥97%.

[0079] On the basis of the alkali-soluble copolymer resin as shown in structural formula (II), a small amount of alkali-soluble copolymer resin containing a styrene structure can be compounded, so as to further reduce the cost while ensuring that the alkali-soluble resin has good flexibility and adhesion, and adapt to the existing dry film preparation process.

[0080] Therefore, in a preferred embodiment, the alkali-soluble resin contains alicyclic alkane (meth) acrylate structural units, and the raw materials include one or more of 1-adamantane (meth) methyl acrylate, 2-adamantane (meth) methyl acrylate, (meth) acrylate tricyclo[5.2.1.02,6]dec-8-yl, 2-methyl-2-adamantanol acrylate, 2-ethyl-2-adamantanol acrylate, 2-carboxy-4-norbornolactone-5-methacrylate, 2-isopropyl-2-adamantanol (meth) acrylate, isobornyl acrylate, acryloyl morpholine, 1-adamantyl methyl acrylate, 3-hydroxy-1-adamantyl (meth) acrylate, cyclohexane dicarboximide acrylate, 2-methyl cyclohexyl acrylate, methyl acrylate-5-oxotetrahydrofuran-3-yl, 5-carboxy-2-tetrahydrofurfuryl alcohol-methacrylate, 1-ethylcyclopentyl methacrylate, 1-isopropyl-1-cyclohexanol methacrylate, 2-cyclohexyl-2-propanol methacrylate, 2-carbonyl-tetrahydrofuran-3-hydroxy-methacrylate, methyl cyclopentyl acrylate, 1-ethylcyclopentyl acrylate, 2-oxotetrahydrofuran-3-yl acrylate, cyclohexyl (meth) acrylate, 1-methyl-1-cyclohexyl methacrylate, 1-methylcyclopentyl methacrylate, 1-ethylcyclohexyl methacrylate, 1-methyl-1-ethyl-1-adamantyl methacrylate, 2-tetrahydrofurfuryl methacrylate, 2-methacrylate-4-hydropyran, dicyclopentyl methacrylate; and / or

[0081] The alkali-soluble resin contains benzyl ester and / or phenoxyethyl ester (meth)acrylate structural units, and the raw materials include one or more of benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, and o-phenylphenoxyethyl acrylate; and / or the alkali-soluble resin contains linear or branched (meth)acrylate structural units, and the raw materials include one or more of methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, isooctyl (meth)acrylate, lauryl (meth)acrylate, and stearyl (meth)acrylate. In addition, the alkali-soluble resin can also contain styrene structural units, and the content of the styrene structural units in the alkali-soluble resin is 0-25 wt%.

[0082] In a preferred embodiment, the photosensitive resin composition includes 45-65 parts by weight of the alkali-soluble resin, 30-50 parts by weight of the photopolymerization monomer, 2.0-5.0 parts by weight of the photoinitiator, 0.05-2.0 parts by weight of the sensitizer, and 0.5-5 parts by weight of the additive. When the amount of the sensitizer is less than 0.05 parts by weight, the photosensitivity of the photosensitive resin composition may be poor; when the amount of the sensitizer is more than 2.0 parts by weight, the surface layer of the photosensitive resin composition may be cured too quickly, which may affect the curing depth and reduce the adhesion of the photosensitive resin composition to the substrate such as copper. When the amount of the photopolymerization monomer is less than 35 parts by weight, the photosensitive resin composition may have low sensitivity and low resolution; when the amount of the photopolymerization monomer is more than 50 parts by weight, the photosensitive layer may be prone to overflow. Therefore, the present application limits the components within the above ranges, so as to more evenly improve the photosensitivity, resolution, and adhesion.

[0083]

Photoinitiator

[0084] In a preferred embodiment, the photoinitiator includes a hexaarylbiimidazole derivative, and the hexaarylbiimidazole derivative has the structure shown in general formula (III):

[0085] A1, A2, A3, A4, A5, and A6 are each independently selected from H, methoxy, and halogen.

[0086] The above photo initiator, due to the low bond energy of the C-N bond in its structure, is easy to break to generate free radicals. Through the analysis of the ultraviolet-visible spectrum, it can be known that its absorption wavelength is between 255-275 nm, and the sensitivity to near ultraviolet light and visible light is very low, while the current industrial exposure light source often uses near visible light LED light source or laser light source with a wavelength of about 400 nm. In order to improve the industrial production efficiency, it is preferred to introduce other photosensitizers and sensitizers into the hexaarylbiimidazole system, and by increasing the photosensitive range of the resist system, the photo initiation ability can be more simply and efficiently improved. Therefore, by adding photosensitizers and hydrogen donors with excellent light absorption range in the photo initiation system, the light absorption range and the final photo curing rate of the hexaarylbiimidazole system can be improved, which is more conducive to the wide application in the production and manufacturing fields of circuit boards, liquid crystal elements, camera color filters, various printing plates and the like.

[0087] In order to further reduce the cost while ensuring good initiation effect, in a preferred embodiment, the photo initiator comprises one or more of 2-(o-chlorophenyl)-4,5-diphenyl imidazole dimer, 2-(o-chlorophenyl)-4,5-di(methoxyphenyl) imidazole dimer, 2-(o-fluorophenyl)-4,5-diphenyl imidazole dimer, 2-(o-methoxyphenyl)-4,5-diphenyl imidazole dimer, 2-(p-methoxyphenyl)-4,5-diphenyl imidazole dimer, 2,2',4-tris(2-chlorophenyl)-5-(3,4-dimethoxyphenyl)-4',5'-diphenyl-1,1'-biimidazole.

[0088] In addition, a small amount of the following substances can also be added to the photo initiator to further improve the initiation effect: one or more of benzil derivatives, acridine derivatives, N-phenyl glycine, coumarin compounds and oxazole compounds; preferably, the benzil derivatives comprise one or more of benzophenone, benzoin methyl ether, N,N'-tetramethyl-4,4'-diaminobenzophenone, thioxanthone, benzoin phenyl ether, N,N'-tetraethyl-4,4'-diaminobenzophenone, 4-methoxy-4'-dimethylaminobenzophenone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone, 2-ethylanthraquinone, phenanthrenequinone, 2-tert-butylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2,3-benzanthraquinone, 2,3-diphenylanthraquinone, 1-chloroanthraquinone, 2-methylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthrenequinone, 2,3-dimethylanthraquinone, methylbenzoate, ethylbenzoate, benzoin phenyl ether, benzil dimethyl ketal; preferably, the acridine derivatives comprise one or more of 9-phenylacridine, 1,7-bis(9,9'-acridinyl)heptane.

[0089]

Photo polymerization monomer

[0090] To further improve the resolution and adhesion of the photosensitive resin composition, in a preferred embodiment, the photopolymerization monomer comprises one or more of monofunctional (meth)acrylate olefinically unsaturated double bond monomer, difunctional (meth)acrylate olefinically unsaturated double bond monomer, multifunctional (meth)acrylate olefinically unsaturated double bond monomer; preferably, the photopolymerization monomer comprises one or more of lauryl (meth)acrylate, stearyl (meth)acrylate, nonyl phenol acrylate, isobornyl acrylate, tetrahydrofurfuryl acrylate, bisphenol A di(meth)acrylate, polyethylene glycol (propylene glycol) di(meth)acrylate, ethoxylated (propoxylated) neopentyl glycol diacrylate, trimethylolpropane tri(meth)acrylate, ethoxylated (propoxylated) trimethylolpropane tri(meth)acrylate, ethoxylated (propoxylated) pentaerythritol triacrylate, ethoxylated (propoxylated) pentaerythritol tetraacrylate, ethoxylated (propoxylated) dipentaerythritol pentaacrylate, ethoxylated (propoxylated) dipentaerythritol hexaacrylate.

[0091] Specifically, in a preferred embodiment, the photopolymerization monomer comprises at least one of the compounds having the structure shown in general formula (IV), general formula (V) or general formula (VI), wherein the EO repeating units and the PO repeating units are randomly arranged or block arranged:

[0092]

[0093] R a selected from H or CH3; the EO repeating units and the PO repeating units account for 20-80 wt% of the photopolymerization monomer; m1 and m2 are respectively integers from 1 to 20, n1 and n2 are respectively integers from 0 to 20, and m1+m2 is an integer from 2 to 20, n1+n2 is an integer from 0 to 20;

[0094]

[0095] R b is H or CH3; a2 is an integer from 4 to 20, b2 is an integer from 0 to 20;

[0096]

[0097] R c is H or CH3; a3 is an integer from 3 to 20, b3 is an integer from 0 to 20, c3 is an integer from 3 to 20.

[0098] The above photopolymerization monomer has better rapid photocuring ability, better resolution, adhesion, chemical resistance, flexibility, and has a balance of EO / PO properties, thereby being more conducive to imparting the dry film resist high resolution performance, high adhesion performance, excellent flexibility and development performance.

[0099]

additives

[0100] For the purpose of facilitating the actual production, in a preferred embodiment, the additives include one or more of radical polymerization inhibitors, coloring agents, invisible coloring agents, plasticizers, photothermal stabilizers, adhesion promoters, leveling agents, and defoaming agents.

[0101] For the purpose of better inhibiting the polymerization in the unexposed part during the formation of the photosensitive resin pattern, further improving the resolution, adhesion, and the performance of the pattern shape, preferably, the radical polymerization inhibitor includes one or more of p-methoxyphenol, 4-ethyl-6-tert-butylphenol, tert-butyl catechol, 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl, nitrosophenyl hydroxylamine aluminum salt, 2-methyl catechol, 3-methyl catechol, 4-methyl catechol, catechol, 2-ethyl catechol, 3-ethyl catechol, 4-ethyl catechol, 2-propyl catechol, 3-propyl catechol, 4-propyl catechol, 2-n-butyl catechol, 3-n-butyl catechol, 4-n-butyl catechol, 2-tert-butyl catechol, 3-tert-butyl catechol, 4-tert-butyl catechol, 3,5-di-tert-butyl catechol, resorcinol, 2-methyl resorcinol, 4-methyl resorcinol, 5-methyl resorcinol, 2-ethyl resorcinol, 4-ethyl resorcinol, 2-propyl resorcinol, 4-propyl resorcinol, 2-n-butyl resorcinol, 4-n-butyl resorcinol, 2-tert-butyl resorcinol, 4-tert-butyl resorcinol, 1,4-hydroquinone, methylhydroquinone, ethylhydroquinone, propylhydroquinone, tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, 2,6-di-tert-butyl-4-methylphenol, pyrogallol, 2,2-methylenebis(4-methyl-6-tert-butylphenol).

[0102] More preferably, the radical polymerization inhibitor includes one or more of p-methoxyphenol, 4-ethyl-6-tert-butylphenol, tert-butyl catechol, 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl, nitrosophenyl hydroxylamine aluminum salt; more preferably, the weight fraction of the radical polymerization inhibitor is 0.001-0.03. From the perspective of further balancing the key performances such as photosensitivity, resolution, adhesion, and resist shape, when the addition amount of the above-mentioned radical polymerization inhibitor is less than 0.001, the resulting resist has the risk of resolution decline, and when the addition amount is more than 0.03, the resulting dry film resist has the risk of poor photosensitivity.

[0103] In another typical embodiment of the present application, a photosensitive dry film is also provided, comprising a support film, a dry film resist layer and an optional protective layer, the raw material of the dry film resist layer comprising the photosensitive resin composition of the present application. It has stronger and more stable photosensitivity, better development, more excellent flexibility and production yield, and a wider range of use scenarios, and can be used for high-precision carrier board manufacturing to meet the performance indicators of high resolution, high adhesion and high thickness in special scenarios.

[0104] In another typical embodiment of the present application, a preparation method of the photosensitive dry film of the present application is also provided, comprising the following steps: step S1, mixing an alkali-soluble resin, a photopolymerization monomer, a photoinitiator, a sensitizer, a free radical polymerization inhibitor and a solvent to obtain a resin composition solution; step S2, coating the resin composition solution on the surface of a PET support film after standing for 25-35 min, and drying to form a dry film resist layer; and step S3, adhering a polyethylene film protective layer to the surface of the dry film resist layer to obtain a photosensitive dry film.

[0105] The alkali-soluble resin, the photopolymerization monomer, the photoinitiator, the sensitizer, the free radical polymerization inhibitor and the solvent are mixed and fully stirred until completely dissolved to obtain a resin composition solution, which is then stood for 25-35 min to fully degas, coated on the surface of a PET support film, and dried to remove the solvent to form a dry film resist layer. Finally, a polyethylene film protective layer is adhered to the surface of the dry film resist layer to obtain a photosensitive dry film. The above preparation method is simple and easy to operate, and the photosensitive dry film prepared thereby can have high resolution, high adhesion, high thickness and high flexibility.

[0106] For the purpose of more convenient actual preparation, in a preferred embodiment, the solvent comprises one or more of acetone, butanone, methanol, ethanol, isopropyl alcohol and toluene; and / or the solid content of the resin composition solution is 35-45%; and / or the drying temperature is 80-100°C and the time is 5-15 min; and / or the thickness of the dry film resist layer is 15-300 μm, preferably 15-220 μm, more preferably 20-200 μm, further preferably 25-100 μm, and most preferably 25-90 μm.

[0107] Typically but not limitedly, in general formula (I), n is 1, 3, 4, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100 or a range value composed of any two of them.

[0108] Typically but not limited to, in general formula (II), a1 is 18 wt%, 20 wt%, 22 wt%, 24 wt%, 25 wt%, 26 wt%, 28 wt%, 30 wt%, 32 wt%, 34 wt%, 35 wt%, or a range value between any two of them, b1 is 0 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, or a range value between any two of them, c1 is 0 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, or a range value between any two of them, d1 is 0 wt%, 2 wt%, 4 wt%, 5 wt%, 6 wt%, 8 wt%, 10 wt%, 12 wt%, 14 wt%, 15 wt%, or a range value between any two of them.

[0109] Typically but not limited to, the thickness of the dry film resist layer is 15 μm, 20 μm, 25 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 120 μm, 150 μm, 180 μm, 200 μm, 220 μm, 250 μm, 280 μm, 300 μm, or a range value between any two of them.

[0110] The present application is further described in detail by the following specific examples, which are not to be construed as limiting the scope of the application as claimed.

[0111] The blank content in the following table means 0 unless otherwise specified.

[0112] 1. Synthesis of Sensitizer

[0113]

[0114] (1) Intermediate Compound 1

[0115] In a 250 mL three-necked flask, concentrated sulfuric acid (30 mL) was added followed by the slow addition of thiosalicylic acid (7.7 g, 0.05 mol) in portions. The temperature rose to 30 °C at this point and at this temperature 1-anthranol (29.1 g, 0.15 mol) was added to the suspension in portions. The reaction mixture was heated to 80 °C and stirred for 12 h. After the reaction, the reaction mixture was poured into ice water (200 g) and a solid precipitate was obtained which was collected by filtration to obtain the crude product. The crude product collected was dispersed in water (100 mL) and cooled in an ice water bath. Solid potassium hydroxide was added slowly under stirring conditions and the pH was adjusted to 14. After the precipitate dissolved, stirring was continued for 60 min. The basic aqueous solution was extracted with ethyl acetate (100 mL each) for 2 times. The basic aqueous solution after extraction was acidified with 1 M hydrochloric acid to pH = 4 and the precipitate was again obtained which was separated by filtration and dried under reduced pressure to obtain the intermediate compound 1 (8.4 g) as shown above.

[0116] 1H NMR (500 MHz) in CDC13: δ 8.86 (s, 1H), 8.60-8.64 (d, J = 7.81 Hz, 1H), 8.40-8.46 (t, J = 16.11 Hz, 1H), 7.96-8.08 (m, 2H), 7.86-7.90 (d, J = 9.27 Hz, 1H), 7.45-7.75 (m, 5H), 5.35 (s, 1H).

[0117] (2) Intermediate compound 2

[0118] Intermediate compound 1 (6.6 g, 0.02 mol) was added to 10 mL of acetonitrile and the mixture was heated to 60 °C. Bromoethyl acetate (6.7 g, 0.04 mol) was added dropwise and the mixture was stirred for 5 min. Potassium hydroxide solution (2.3 g, 0.04 mol in 10 mL water) was added to adjust the pH to 12. The reaction mixture was heated to 80 °C and stirred for 2 h. The reaction mixture was allowed to cool to room temperature and 30 mL of water was added. The crude product was obtained by filtration. The solid crude product obtained was dispersed in a mixture of petroleum ether: ethyl acetate (100 mL) and stirred at room temperature for 30 min. The solid was collected by suction filtration and dried using a rotary evaporator to remove the small amount of solvent entrapped in the solid to obtain the intermediate compound 2 (6.1 g) as shown above.

[0119] (3) Intermediate compound 3

[0120] In a 100 mL three-necked flask, intermediate compound 2 (6.1 g, 0.015 mol), methanol (50 mL), water (5 mL), LiOH-H2O (1.26 g, 0.03 mol) were added and stirred at room temperature. After the addition was completed, the reaction mixture was stirred at room temperature for 4 h. The reaction was monitored by TLC plate. When the starting material was consumed, water (20 mL) was added and the mixture was extracted with ethyl acetate (50 mL x 2). The ethyl acetate phase contained a small amount of impurities and no target product, so it was discarded. The aqueous phase was acidified to pH = 5 with 1 M hydrochloric acid and extracted with ethyl acetate (50 mL x 3). The organic phase was combined, dried over a small amount of anhydrous sodium sulfate, filtered, and the filtrate was distilled under reduced pressure to remove the solvent to obtain intermediate compound 3 (5.5 g) as shown above.

[0121] (4) Intermediate compound 4

[0122] In a 100 mL three-necked flask, intermediate compound 3 (5.5 g, 0.014 mol), dichloromethane (50 mL), anhydrous N,N-dimethylformamide (3 drops), and the solution system were subjected to nitrogen replacement and cooled in an ice-water bath. Oxalyl chloride (1.77 mL, 0.021 mol) was slowly added dropwise under nitrogen protection at 0°C. After the addition was completed, the reaction solution was stirred at room temperature for 2 h. The reaction solution was distilled under reduced pressure to remove the solvent to obtain intermediate compound 4 crude product (5.7 g) as shown above. Without purification, it was directly used in the next step reaction as soon as possible.

[0123] (5) Synthesis of sensitizer sensilizer D-1

[0124] In a 100 mL three-necked flask, ethylene glycol (0.43 g, 0.007 mol), acetonitrile (60 mL), and triethylamine (2.1 g, 0.021 mol) were added, and the solution system was subjected to nitrogen replacement and cooled in an ice-water bath. A solution of intermediate compound 4 crude product (5.7 g) dissolved in 10 mL of acetonitrile was slowly added dropwise under nitrogen protection at 0°C. After the addition was completed, the reaction solution was reacted in an ice-water bath for 30 min, at room temperature for 2 h, and then heated to 80°C for 12 h. The reaction solution was cooled to room temperature, 100 mL of water was added, and the mixture was extracted with ethyl acetate (80 mL x 3). The organic phase was combined, concentrated under reduced pressure to obtain a crude product. The crude product was stirred in a small amount of ethanol (50 mL) at room temperature for 30 min, filtered, and the solid was dried with a rotary evaporator to remove a small amount of solvent wrapped in the solid to obtain a double-function sensitizer D-1 with an alkoxy long-chain modified thioxanthone and anthracene structure as shown above, which has the structure shown in general formula (I).

[0125] 2. Synthesis of an alkali-soluble resin

[0126] The compounds shown in general formula (II) were prepared by free radical solution polymerization. The monomers corresponding to the segments in the structure of the compounds shown in general formula (II) were all purchased directly. A series of alkali-soluble resins A-1 to A-8 were synthesized according to the formulations in Table 1 below, and the preparation method included the following steps:

[0127] The monomers corresponding to the segments a, b, c, and d in the structure of the compounds shown in general formula (II) were mixed uniformly according to the weight ratio (100 g in total), and then mixed with 1.0 g of AIBN photoinitiator, 90 g of butanone, and 15 g of ethanol. The mixture was stirred and dissolved, and then about 35% of the mixed solution was added to a three-necked flask with nitrogen protection and condensation reflux device through a peristaltic pump. The oil bath was heated to 80°C, and after stirring for 1 h, the remaining mixed solution was added dropwise, which was completed within 3 h. After continuing to incubate for 4 h, the temperature was increased to 90°C, and 5 g of butanone solution containing 0.2 g of initiator was added twice with an interval of 1 h. After the dropwise addition was completed, the temperature was incubated and stirred for 2 h, and the reaction was stopped. The alkali-soluble resin with the structure shown in general formula (II) was obtained, and its weight average molecular weight and molecular weight distribution were measured by GPC.

[0128] Table 1

[0129]

[0130] 3. Formulation of a photosensitive resin composition

[0131] The components were mixed in proportions according to the formulations in Tables 2 and 3 below, and 60 parts by weight of a solvent was added, wherein the solvent suitable for preparing a coating glue solution was acetone. Then, the mixture was fully stirred until completely dissolved to prepare a resin composition solution with a solid content of 40%. After standing for 30 min and fully degassing, the solution was uniformly coated on the surface of a PET support film with a thickness of 16 μm using a coating machine, and then placed in an oven at 90°C for 10 min to form a dry film resist layer with a thickness of 25 μm, which was used as a photosensitive resin composition system for IC carrier board manufacturing, or a dry film resist with high resolution, high adhesion, and high thickness for special scenarios. The dry film resist layer appeared blue-green under a yellow light. Then, a polyethylene film protective layer with a thickness of 20 μm was attached to the surface to obtain a 3-layer photosensitive dry film.

[0132] Table 2

[0133]

[0134]

[0135] Table 3

[0136]

[0137]

[0138] Alkali-soluble resin A:

[0139] A-1 to A-8 are shown in Table 1;

[0140] A-9: methacrylic acid: methyl methacrylate: styrene: benzyl methacrylate = 25:6:45:24, GPC measured weight average molecular weight is 35000 g / mol, molecular weight distribution 1.8, conversion rate 97.0%.

[0141] Photopolymerizable monomer B:

[0142] B-1: ethoxylated bisphenol A diacrylate (Meiyou Special Chemicals), which has the structure shown in general formula (IV), wherein R a is H, n1+n2=0, m1+m2=4;

[0143] B-2: ethoxylated bisphenol A diacrylate (Meiyou Special Chemicals), which has the structure shown in general formula (IV), wherein R a is H, n1+n2=0, m1+m2=10;

[0144] B-3: ethoxylated polypropylene glycol dimethacrylate (Meiyou Special Chemicals), which has the structure shown in general formula (VI), wherein R c is CH3, a3 is 3, b3 is 12, and c3 is 3;

[0145] B-4: ethoxylated trimethylolpropane trimethacrylate (Meiyou Special Chemicals);

[0146] B-5: ethoxylated nonylphenol methacrylate (Meiyou Special Chemicals).

[0147] Photoinitiator C:

[0148] C-1: 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole BCIM (Changzhou Qiangli Electronic Materials).

[0149] Sensitizer D:

[0150] Sensitizers D-1 to D-8 all have the structure shown in general formula (I), and the synthesis methods of D-2 to D-8 are basically similar to the synthesis route and steps of sensitizers D-1, only the structure formula and molecular weight of the diol raw material in the last step of reaction with intermediate compound 4 are slightly different. Different chain length diol raw materials are used to participate in the reaction, and sensitizers with different target molecular weights are synthesized.

[0151] D-1: R0 is CH2CH2-, n=1, molecular weight is 796;

[0152] D-2: R° is CH2CH2-, n = 4 (diol is PEG200), molecular weight is 950, the synthesis steps are basically as shown in the synthesis example D-1, and PEG200 raw material is used to participate in the reaction in the last step of the reaction;

[0153] D-3: R° is CH2CH2-, n = 8 (diol is PEG400), molecular weight is 1150, the synthesis steps are basically as shown in the synthesis example D-1, and PEG400 raw material is used to participate in the reaction in the last step of the reaction;

[0154] D-4: R° is CH2CH2-, n = 45 (diol is PEG2000), molecular weight is 2750, the synthesis steps are basically as shown in the synthesis example D-1, and PEG2000 raw material is used to participate in the reaction in the last step of the reaction;

[0155] D-5: R° is CH2CH(CH3)-, n = 3 (diol is PPG200), molecular weight is 950, the synthesis steps are basically as shown in the synthesis example D-1, and PPG200 raw material is used to participate in the reaction in the last step of the reaction;

[0156] D-6: R° is CH2CH2-, n = 90 (diol is PEG4000), molecular weight is 4750, the synthesis steps are basically as shown in the synthesis example D-1, and PEG4000 raw material is used to participate in the reaction in the last step of the reaction;

[0157] D-7: R° is CH2CH2-, n = 136 (diol is PEG6000), molecular weight is 6750, the synthesis steps are basically as shown in the synthesis example D-1, and PEG6000 raw material is used to participate in the reaction in the last step of the reaction;

[0158] D-8: 9,10-dibutoxyanthracene (DBA).

[0159] Additives:

[0160] E-1: 4-tert-butylcatechol;

[0161] E-2: Brilliant green pigment (Shanghai Bailingwei Chemical Technology Co., Ltd.);

[0162] E-3: Leuco crystal violet (Shanghai Bailingwei Chemical Technology Co., Ltd.);

[0163] E-4: p-methylbenzenesulfonamide (Shanghai Tixi'ai Chemical Industry Co., Ltd.).

[0164] The following describes the sample preparation method (including film pasting, exposure, development, and copper electroplating) of the examples and comparative examples, the sample evaluation method, and the evaluation results.

[0165] (1) Sample preparation method

[0166]

Film

[0167] The copper-clad plate is polished by a polisher to polish the copper surface, washed with water, and dried to obtain a bright and fresh copper surface. The temperature of the pressing roller of the film laminator is set to 110°C, the conveying speed is 1.5 m / min, and the film is laminated under standard pressure.

[0168]

Exposure

[0169] After the film is laminated, the sample is exposed to light for more than 15 minutes using a Japanese Adtec exposure machine, model IP-6, a laser direct imaging (LDI) exposure machine with a wavelength of 405 nm, and a stouffer 41-step exposure ruler for photosensitivity testing. The exposure grid number is controlled to be 13-17.

[0170]

Development

[0171] After exposure, the sample is left to stand for more than 15 minutes, the development temperature is 30°C, the pressure is 1.2 Kg / cm 2 , the developing solution is 1wt% sodium carbonate aqueous solution, the development time is 1.5-2.0 times the minimum development time, and after development, the sample is washed with water and dried. The minimum time required to completely dissolve the unexposed part of the resist layer is taken as the minimum development time.

[0172]

Etching

[0173] The developed copper plate is subjected to an etching process, the etching solution is copper chloride, the etching speed is 1.0 m / min, the etching temperature is 48°C, the spray pressure is 1.5 bar, the specific gravity is 1.3 g / mL, the acidity is 2 mol / L, the copper ion concentration is 140 g / L, and the etching machine model is Dongguan Universe GL181946.

[0174]

Film stripping

[0175] The film stripping solution is NaOH with a concentration of 3.0wt%, a temperature of 50°C, and a pressure of 1.2 Kg / cm 2 , the film stripping time is 1.5-2.0 times the minimum film stripping time, and after film stripping, the sample is washed with water and dried.

[0176] (2) Evaluation method

[0177]

Evaluation of photosensitivity

[0178] After the film was attached, the sample was left to stand for 15 minutes or more, and then exposed using an Adtec IP-6 405 nm LDI exposure machine. The photosensitivity was tested using a stouffer 41-step exposure scale. After exposure, the unexposed portions were removed by spraying a 1 wt% aqueous sodium carbonate solution at 30°C for 2.0 times the minimum development time. After this operation, a cured film formed of a cured product of the photosensitive resin composition was formed on the copper surface of the substrate, the dry film resist film thickness was 25 μm, and the exposure amount (mJ / cm 2 ) at which the number of remaining segments of the stage exposure table obtained as the cured film was 15 segments was determined. The photosensitivity of the photosensitive resin composition was evaluated. The smaller this value, the better the photosensitivity.

[0179] Judgment basis: O: 25 to 35 mJ / cm 2 , Δ: 40 to 55 mJ / cm 2 , X: > 55 mJ / cm 2 .

[0180] [Resolution Evaluation]

[0181] Exposure was performed using a mask having a wiring pattern with a width ratio of exposed portion to unexposed portion of 1:1. After development for 2 times the minimum development time, the minimum mask width at which a normal cured resist line was formed was taken as the value of the resolution, and observation was performed using a metallographic microscope or a scanning electron microscope (SEM). The smaller the read number, the better the resolution.

[0182] [Adhesion Evaluation]

[0183] A photosensitive dry film resist was laminated on a copper plate by hot-pressing film attachment. Exposure was performed using a mask having a wiring pattern with a width ratio of exposed portion to unexposed portion of n:400. After development for 2 times the minimum development time, observation was performed using a magnifying glass, and the minimum mask width at which a complete cured resist line was formed was taken as the value of the adhesion. The smaller the read number, the better the adhesion.

[0184] [Flexibility Evaluation]

[0185] The dry film resist was laminated to the FPC substrate as a test piece for evaluating the flexibility. After the film was attached, the sample was left to stand for 15 minutes or more, and exposed using an Adtec IP-6 405 nm LDI exposure machine. A stouffer 41-step exposure scale was used to test the photosensitivity, and a dry film resist having a thickness of 25 μm was exposed using an energy level of 15, and a dry film resist having a thickness of 90 μm was exposed using an energy level of 20. After development using a development time twice the minimum development time, a substrate having a dry film resist laminated to the FPC substrate was obtained. The flexibility was evaluated using a mandrel tester. The substrate for evaluating the flexibility was cut into a long strip having a width of 2 cm and a length of 10 cm, and after rubbing the long strip against a cylindrical rod at 180° for 10 rounds, the condition of the dry film resist on the substrate was confirmed, and the diameter of the rod corresponding to the case where the dry film resist did not peel or crack was recorded.

[0186] Dry film resist having a thickness of 25 μm, judgment basis: O: 3 mm did not crack Δ: 4 mm did not crack X: 5 mm or more did not crack.

[0187] Dry film resist having a thickness of 90 μm, judgment basis: O: 10 mm did not crack Δ: 14 mm did not crack X: 18 mm or more did not crack.

[0188] [Photosensitizer migration rate evaluation]

[0189] The 3-layer photosensitive dry film prepared above was left to stand at 30°C for 48 hours, and the ultraviolet absorption spectrum of the dry film was measured using a UV spectrophotometer to obtain the absorbance Al of the maximum absorption peak in the range of 350 to 450 nm. The PE film layer on the surface of the photosensitive dry film was removed, and the ultraviolet absorption spectrum of the PET layer and the photosensitive resist layer was measured using a UV spectrophotometer to obtain the absorbance A2 of the maximum absorption peak in the range of 350 to 450 nm. If the photosensitizer migrated to the surface of the PE layer, the absorbance of the maximum absorption peak of the PET layer and the photosensitive resist layer in the range of 350 to 450 nm would decrease, and the absorbance of the photosensitizer that migrated to the PE layer would be (Al - A2). The migration degree of the photosensitizer, i.e., the migration rate A = (Al - A2) ÷ Al, was calculated, and the greater the value, the greater the migration amount.

[0190] Judgment basis: O: migration rate A < 0.01; X: migration rate A > 0.01.

[0191] [Photosensitizer dissolution rate evaluation]

[0192] 0.5 g of an anthracene photosensitizer solid compound was weighed into a transparent glass bottle, 10 g of acetone was added, and the bottle was placed in a 30°C water bath. The time required for the solid material to completely dissolve from the time the bottle was placed in the water bath was observed and recorded. The shorter the time, the faster the dissolution rate.

[0193] Judgment basis: O: completely dissolved within 1 hour; Δ: completely dissolved within 2 to 3 hours; X: completely dissolved in 5 hours or more.

[0194] [Evaluation of the amount of precipitate]

[0195] The dried photosensitive resin layer was peeled off, and 18 g of the photosensitive layer resist was dissolved in 1 L of 1% Na2CO3 developing solution. After the photosensitive layer was completely dissolved, the solution was poured into a micro developing machine, and after 90 minutes of spraying circulation at 30°C / 0.12 MPa pressure, the circulation was stopped. The circulated developing solution was taken out and left to stand for 7 days, and then the precipitate was filtered with filter paper and dried to weigh, and the weight of the precipitate on the filter paper was investigated in terms of the percentage value of the initial 18 g of the photosensitive layer.

[0196] Judgment basis: O: 0 to 0.4%; Δ: 0.4% to 0.8%; X: > 0.8%.

[0197] [Side edge appearance evaluation]

[0198] After the PE film of the manufactured photosensitive dry film resist was removed, lamination dry film was performed on a copper plate using a heated press roller. Here, exposure was performed using a mask having a wiring pattern with a width of n:400 of exposed and unexposed portions, the exposure energy was 15 grids corresponding to the sensitivity, and after development with 2.0 times the minimum development time, a dry film image was obtained, and a side view of the dry film with a line width of 15 μm was photographed at 1000 times magnification using a scanning electron microscope (SEM). The photomicrograph of the film thickness 25 μm, and the independent attachment 8 μm is shown in Figure 1 , and the photomicrograph of the film thickness 90 μm, and the resolution 22 μm is shown in Figure 2 .

[0199] Judgment basis: O: the head section of the dry film is rectangular; Δ: the head section of the dry film somewhat appears to be an inverted trapezoid; X: the head section of the dry film is seriously an inverted trapezoid or the bottom is hollowed out, or a phenomenon of a significant crack in the side wall occurs.

[0200] The performance evaluation results are shown in Tables 4 to 5.

[0201] Table 4

[0202]

[0203]

[0204] Table 5

[0205]

[0206] From the comparison of Examples 1 to 12 and Comparative Examples 1 to 4, it can be found that the dry film resists of Examples 1 to 12 have excellent key comprehensive performances such as photosensitivity, resolution, adhesion performance, flexibility grade, initiator migration, and development sedimentation, and are suitable for manufacturing high-order PCBs such as carrier boards and carrier board-like boards.

[0207] In Comparative Example 1, the initiator system is a hexaarylbiimidazole derivative combined with a conventional anthracene sensitizer (DBA), and a high benzene resin is used. The initiator and resin system is a commonly used initiator system for dry film resists for manufacturing high-order PCBs such as carrier boards and carrier board-like boards. The addition amount of DBA is obviously higher than that of the sensitizer in the examples, but the sensitivity is still somewhat low, and the migration of DBA to the polyethylene protective film is obviously poor. In addition, since a high benzene resin is used, the flexibility of the dry film resist is extremely poor.

[0208] In Comparative Example 2, the sensitizer used is the dual-function sensitizer of the application, and the sensitivity of the corresponding dry film resist is obviously improved. However, since a conventional high benzene resin is used, the flexibility of the obtained dry film resist does not reach the best state.

[0209] In Comparative Example 3, the initiator system is a hexaarylbiimidazole derivative combined with a conventional anthracene sensitizer (DBA), and the flexibility is obviously improved, but the sensitivity is still somewhat low, and the migration of DBA to the polyethylene protective film is obviously poor.

[0210] In Comparative Example 4, the sensitizer used is the dual-function sensitizer of the application, but the molecular weight is larger than the preferred molecular weight range, and the photosensitivity of the obtained dry film resist is slightly low.

[0211] From the comparison of Examples 13 to 20 and Comparative Examples 5 to 7, it can be found that the dry film resists of Examples 13 to 20 have excellent key comprehensive performances such as photosensitivity, resolution, adhesion performance, flexibility grade, initiator migration, and side edge appearance, and are suitable for special scenarios.

[0212] In Comparative Example 5, the initiator system is a hexaarylbiimidazole derivative combined with a conventional anthracene sensitizer (DBA), and a high benzene resin is used. The initiator and resin system is also a commonly used initiator system for high-thickness dry film resists. With the increase of thickness and exposure degree, the flexibility decreases sharply, the side edge appearance is slightly poor, and the migration of DBA to the polyethylene protective film is obviously poor.

[0213] In Comparative Example 6, a conventional high benzene resin is used, and the flexibility of the obtained high-thickness dry film resist is extremely poor, which will obviously reduce the use yield of the customer end.

[0214] In Comparative Example 7, a conventional anthracene (DBA) sensitizer was used, and the migration of DBA to the polyethylene protective film was obvious.

[0215] As can be seen from the above, compared with the comparative examples, the embodiments of the present application modify the molecular structure of the conventional anthracene sensitizer, introduce specific photosensitive unit structures to increase photosensitivity, increase the molecular weight, and reduce the migration of the anthracene sensitizer; at the same time, the water solubility can be increased, and the development and precipitation phenomenon can be improved. The present application uses an optimized modified high photosensitivity and low migration sensitizer compound system, and is matched with suitable alkali-soluble resin, photopolymerization monomer and other components, so that a photosensitive resin composition with high photosensitivity and high resolution can be obtained, and the sensitivity, resist pattern and other aspects of performance are more stable, and the application requirements of high resolution, high adhesion and high thickness for high-precision IC carrier board and special scene use of high-order PCB manufacturing can be met.

[0216] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A photosensitive resin composition, characterized by comprising: The photosensitive resin composition comprises an alkali-soluble resin, a photopolymerization monomer, a photoinitiator, a sensitizer and an additive; wherein the sensitizer comprises a compound having a structure shown in general formula (I): （I）； wherein A is , the sensitizing agent contains a structural unit of thioxanthone and a structural unit of anthracene; R0 is selected from C2-C12 linear or branched alkylene; R' is selected from H, halogen, nitro, C1-C8 linear or branched alkyl, C1-C4 linear or branched alkoxy, C6-C18 aryl; n is an integer of 1-100; The alkali-soluble resin comprises a copolymer having a structure shown in general formula (II): (II); R1, R2, R3, R4 are independently selected from H, methyl; R5 is selected from C1-C5 linear or branched alkyl, C1-C5 linear or branched alkoxy, hydroxyl, halogen; R6 is selected from C1-C10 linear or branched alkylene; R is selected from C5-C14 substituted or unsubstituted monocyclic carbocyclic alkyl, C5-C14 substituted or unsubstituted polycyclic carbocyclic alkyl, C5-C14 substituted or unsubstituted monocyclic heterocyclic alkyl, C5-C14 substituted or unsubstituted polycyclic heterocyclic alkyl, and the polycyclic carbocyclic alkyl has a fused ring structure or a bridged ring structure; R" is selected from C1-C18 linear or branched alkyl; X is an integer of 0-5; Y is an integer of 0-5; a1, b1, c1, d1 are the weight percentages of each structural unit in the alkali-soluble resin, a1 is 18-35 wt%, b1 is 0-60 wt%, c1 is 0-80 wt%, and d1 is 0-15 wt%.

2. The photosensitive resin composition according to claim 1, characterized by In the general formula (I), R0 is selected from CH2CH2-, CH2CH(CH3)-, -(CH2)4, -(CH2)6; and / or R' is selected from H, Cl, Br, nitro, C1-C8 linear or branched alkyl, C1-C4 linear or branched alkoxy, C6-C18 aryl; and / or n is an integer of 1-100; and / or The molecular weight of the sensitizer is 600-6000.

3. The photosensitive resin composition according to claim 1 or 2, characterized in that, The molecular weight of the sensitizer is 700-4000; and / or The C5-C14 substituted or unsubstituted polycyclic carbocyclic alkyl is C5-C14 substituted or unsubstituted bicyclic carbocyclic alkyl, and the bicyclic carbocyclic alkyl has a fused ring structure or a bridged ring structure; and / or The C5-C14 substituted or unsubstituted polycyclic heterocyclic alkyl is C5-C14 substituted or unsubstituted bicyclic heterocyclic alkyl.

4. The photosensitive resin composition according to claim 1 or 2, characterized by In the general formula (II), R5 is selected from methyl, methoxy, hydroxyl, halogen; and / or R6 is selected from methyl, ethyl, propyl; and / or R is selected from 1-adamantyl, dicyclopentyl, cyclohexyl, isobornyl; and / or R" is selected from methyl, ethyl, propyl, n-butyl, isobutyl, isooctyl; and / or X is an integer of 0-2; and / or Y is an integer of 0-5; and / or a1 is 20-30 wt%, b1 is 20-40 wt%, c1 is 20-50 wt%, and d1 is 3-10 wt%.

5. The photosensitive resin composition according to claim 4, characterized by In R", the propyl is isopropyl.

6. The photosensitive resin composition according to claim 1 or 2, characterized by The alkali-soluble resin has an acid value of 120-250 mg KOH / g, a weight average molecular weight of 25000-60000, a molecular weight distribution of 1.3-2.5, and a polymerization conversion rate of ≥97%.

7. The photosensitive resin composition according to claim 1 or 2, characterized by comprising: The alkali-soluble resin contains alicyclic alkane (meth)acrylate structural units, and the raw materials include one or more of 1-adamantane (meth) methyl acrylate, 2-adamantane (meth) methyl acrylate, (meth) acrylate of tricyclo[5.2.1.02,6]dec-8-yl, 2-methyl-2-adamantanol acrylate, 2-ethyl-2-adamantanol acrylate, 2-carboxy-4-norbornolactone-5-methacrylate, 2-isopropyl-2-adamantanol (meth) acrylate, isobornyl acrylate, acryloyl morpholine, 3-hydroxy-1-adamantane (meth) acrylate, cyclohexane dicarboximide acrylate, cyclohexyl methacrylate, 5-oxotetrahydrofuran-3-yl methacrylate, 5-carboxy-2-tetrahydrofurfuryl alcohol-methacrylate, 1-ethylcyclopentyl methacrylate, 1-isopropyl-1-cyclohexanol methacrylate, 2-cyclohexyl-2-propanol methacrylate, 2-ketotetrahydrofuran-3-hydroxy-methacrylate, methylcyclopentyl acrylate, 1-ethylcyclopentyl acrylate, 2-oxotetrahydrofuran-3-yl acrylate, cyclohexyl (meth) acrylate, 1-methyl-1-cyclohexyl methacrylate, 1-methylcyclopentyl methacrylate, 1-ethylcyclohexyl methacrylate, 1-methyl-1-ethyl-1-adamantane methacrylate, 2-tetrahydrofuryl methacrylate, 2-methacrylate-4-hydropyran, dicyclopentyl methacrylate; and / or The alkali-soluble resin contains benzyl ester and / or phenoxyethyl ester (meth) acrylate structural units, and the raw materials include one or more of benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, o-phenyl phenoxyethyl acrylate; and / or The alkali-soluble resin contains linear or branched (meth) acrylate structural units, and the raw materials include one or more of methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, isooctyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate.

8. The photosensitive resin composition according to claim 7, characterized by The propyl (meth) acrylate is isopropyl (meth) acrylate.

9. The photosensitive resin composition according to claim 1 or 2, characterized by comprising: The photosensitive resin composition includes 45-65 parts by weight of the alkali-soluble resin, 30-50 parts by weight of the photopolymerization monomer, 2.0-5.0 parts by weight of the photoinitiator, 0.03-2.0 parts by weight of the sensitizer, and 0.5-5 parts by weight of the additive.

10. The photosensitive resin composition according to claim 1 or 2, characterized by comprising: The photoinitiator includes a hexaaryl bisimidazole derivative having a structure represented by general formula (III): (III); A1, A2, A3, A4, A5, A6 are independently selected from H, methoxy, halogen atom.

11. The photosensitive resin composition according to claim 10, characterized by The photo initiator comprises one or more of 2-(o-chlorophenyl)-4,5-diphenyl imidazole dimer, 2-(o-chlorophenyl)-4,5-di(methoxyphenyl) imidazole dimer, 2-(o-fluorophenyl)-4,5-diphenyl imidazole dimer, 2-(o-methoxyphenyl)-4,5-diphenyl imidazole dimer, 2-(p-methoxyphenyl)-4,5-diphenyl imidazole dimer, 2,2',4-tris(2-chlorophenyl)-5-(3,4-dimethoxyphenyl)-4',5'-diphenyl-1,1'-biimidazole.

12. The photosensitive resin composition according to claim 1 or 2, characterized by comprising: The photo polymerization monomer comprises one or more of a monofunctional (meth)acrylate olefinically unsaturated double bond monomer and a multifunctional (meth)acrylate olefinically unsaturated double bond monomer.

13. The photosensitive resin composition according to claim 12, characterized by The multifunctional (meth)acrylate olefinically unsaturated double bond monomer is a difunctional (meth)acrylate olefinically unsaturated double bond monomer.

14. The photosensitive resin composition according to claim 1 or 2, characterized by comprising: The photo polymerization monomer comprises one or more of lauryl (meth)acrylate, stearyl (meth)acrylate, nonyl phenol acrylate, isobornyl acrylate, tetrahydrofurfuryl acrylate, bisphenol A di(meth)acrylate, polyethylene glycol (propylene glycol) di(meth)acrylate, ethoxylated (propoxylated) neopentyl glycol diacrylate, trimethylolpropane tri(meth)acrylate, ethoxylated (propoxylated) trimethylolpropane tri(meth)acrylate, ethoxylated (propoxylated) pentaerythritol triacrylate, ethoxylated (propoxylated) pentaerythritol tetraacrylate, ethoxylated (propoxylated) dipentaerythritol pentaacrylate, and ethoxylated (propoxylated) dipentaerythritol hexaacrylate.

15. The photosensitive resin composition according to claim 12, characterized by The photo polymerization monomer comprises at least one of a compound having a structure represented by general formula (IV), general formula (V), or general formula (VI), wherein the EO repeating units and the PO repeating units are randomly arranged or block arranged: (IV); R a is selected from H or CH3; The weight percentage of the EO repeating units and the PO repeating units in the photo polymerization monomer is 20-80 wt%; m1 and m2 are respectively integers of 1-20, n1 and n2 are respectively integers of 0-20, m1+m2 is an integer of 2-20, and n1+n2 is an integer of 0-20; （V）； R b is H or CH3; a2 is an integer of 4-20, and b2 is an integer of 0-20; (WE); R c is H or CH3; a3 is an integer of 3-20, b3 is an integer of 0-20, and c3 is an integer of 3-20.

16. The photosensitive resin composition according to claim 1 or 2, characterized by comprising: The additive comprises one or more of a free radical polymerization inhibitor, a tinting agent, a plasticizer, a photothermal stabilizer, an adhesion promoter, a leveling agent, and a defoaming agent.

17. The photosensitive resin composition according to claim 16, characterized by The tinting agent is a colorless tinting agent.

18. The photosensitive resin composition according to claim 16, characterized by The free radical polymerization inhibitor includes one or more of p-methoxyphenol, 4-ethyl-6-tert-butylphenol, tert-butylcatechol, 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl, nitrosophenylhydroxylamine aluminum salt, 2-methylcatechol, 3-methylcatechol, 4-methylcatechol, catechol, 2-ethylcatechol, 3-ethylcatechol, 4-ethylcatechol, 2-propylcatechol, 3-propylcatechol, 4-propylcatechol, 2-n-butylcatechol, 3-n-butylcatechol, 4-n-butylcatechol, 2-tert-butylcatechol, 3-tert-butylcatechol, 4-tert-butylcatechol, 3,5-di-tert-butylcatechol, resorcinol, 2-methylresorcinol, 4-methylresorcinol, 5-methylresorcinol, 2-ethylresorcinol, 4-ethylresorcinol, 2-propylresorcinol, 4-propylresorcinol, 2-n-butylresorcinol, 4-n-butylresorcinol, 2-tert-butylresorcinol, 4-tert-butylresorcinol, 1,4-hydroquinone, methylhydroquinone, ethylhydroquinone, propylhydroquinone, tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, 2,6-di-tert-butyl-4-methylphenol, pyrogallol, 2,2-methylenebis(4-methyl-6-tert-butylphenol).

19. The photosensitive resin composition according to claim 16, wherein The free radical polymerization inhibitor includes one or more of p-methoxyphenol, 4-ethyl-6-tert-butylphenol, tert-butylcatechol, 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl, nitrosophenylhydroxylamine aluminum salt.

20. The photosensitive resin composition according to claim 16, wherein The free radical polymerization inhibitor is 0.001 to 0.03 parts by weight.

21. A photosensitive dry film characterized by comprising: The dry film resist layer includes a support film, a dry film resist layer, and an optional protective layer, and the raw material of the dry film resist layer includes the photosensitive resin composition of any one of claims 1 to 20.

22. The method for preparing the photosensitive dry film according to claim 21, characterized in that, The method includes the following steps: Step S1, mixing an alkali-soluble resin, a photopolymerization monomer, a photoinitiator, a sensitizer, a free radical polymerization inhibitor, and a solvent to obtain a resin composition solution; Step S2, after the resin composition solution is left to stand for 25 to 35 min, coating on the surface of a PET support film, drying to form a dry film resist layer; Step S3, laminating a polyethylene film protective layer on the surface of the dry film resist layer to obtain the photosensitive dry film.

23. The method of claim 22, wherein, The solvent includes one or more of acetone, butanone, methanol, ethanol, isopropanol, and toluene; and / or the solid content of the resin composition solution is 35 to 45%; and / or the drying temperature is 80 to 100°C, and the time is 5 to 15 min; and / or the thickness of the dry film resist layer is 15 to 300 μm.

Images