Photosensitive resin, preparation method thereof, and photosensitive resin composition

Abstract

This invention belongs to the field of semiconductor packaging, and provides a photosensitive resin, its preparation method, and a photosensitive resin composition. The photosensitive resin is formed by an electrophilic substitution reaction of a phenolic prepolymer and an electrophilic reagent. The phenolic prepolymer is formed by a polycondensation reaction of monomer I (structure shown in Formula 1) and monomer II (structure shown in Formula 2), wherein m and n independently represent 1 or 2, and Ar is an aryl group with 6 to 18 carbon atoms. When this resin is applied to a photosensitive resin composition, the cured material formed by the composition possesses good etching resistance, mechanical properties, and high thermal stability.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor packaging, specifically relating to a photosensitive resin, its preparation method, and a photosensitive resin composition. Background Technology

[0002] In the manufacture of semiconductor devices and display panels, polyimide resins, polybenzoxazole resins, and similar materials have become indispensable key materials in surface protective layers and interlayer insulating layers due to their excellent electrical insulation, high thermal stability, good mechanical strength, and chemical inertness. These materials mainly perform functions such as electrical isolation, mechanical protection, and blocking the intrusion of moisture and impurity ions, thereby ensuring the long-term reliability of the devices. However, the high performance of these materials stems from the rigid aromatic heterocyclic structure formed in the polymer backbone during the curing stage, such as the imine ring of polyimide or the oxazole ring of polybenzoxazole. This cyclization reaction requires high-temperature conditions of 300~350℃ to be fully completed in order to achieve the desired final performance.

[0003] High-temperature processes present two significant challenges: firstly, the extremely high thermal budget drastically increases production energy consumption and process costs; secondly, for silicon wafers with mismatched coefficients of thermal expansion, especially heat-sensitive flexible substrates, high temperatures can easily induce substrate warping and deformation, and even cause delamination between the functional layer and the substrate interface. Therefore, the application of such materials in the pursuit of thinner, more flexible semiconductors and advanced packaging devices is severely limited. To address this, phenolic photosensitive resin compositions, as a classic patterning material system, are considered a potential solution. These resins are rich in phenolic hydroxyl groups in their basic structure, allowing for patterning through UV exposure under the influence of photosensitive components. Then, with the aid of a curing agent, thermal cross-linking occurs at a relatively low temperature of 100–250°C, forming a three-dimensional network structure. This low-temperature curing characteristic makes phenolic photosensitive resins promising for applications in heat-budget-sensitive scenarios.

[0004] However, existing phenolic photosensitive resins still have several performance shortcomings when meeting the requirements of semiconductor-grade applications: insufficient mechanical strength after curing, making them prone to damage under subsequent grinding or stress; and poor chemical resistance, making them unable to withstand the corrosion of chemicals in wet etching or electroplating processes. These problems limit the direct application of such materials in high-end semiconductor processes. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, the present invention aims to provide a photosensitive resin, its preparation method, and a photosensitive resin composition. When this resin is applied to a photosensitive resin composition, the resulting coating exhibits excellent etching resistance, mechanical properties, and high thermal stability.

[0006] In a first aspect, the present invention provides a photosensitive resin formed by an electrophilic substitution reaction of a phenolic prepolymer and an electrophilic agent, wherein the phenolic prepolymer is formed by a polycondensation reaction of monomer I with the structure shown in Formula 1 and monomer II with the structure shown in Formula 2.

[0007] In Equation 1, m and n each independently represent 1 or 2; in Equation 2, Ar is an arylene with 6 to 18 carbon atoms. The electrophilic reagent is an aldehyde compound and / or a polymethoxymethyl compound.

[0008] The photosensitive resin provided by this invention belongs to a modified phenolic polymer. The main chain of this resin is formed by the polycondensation reaction of a dibenzo-dioxin structure (monomer I) substituted with polyhydroxyl (-OH) groups and a dihydroxymethyl aryl structure (monomer II). The hydroxyl-substituted dibenzo-dioxin structural unit derived from monomer I, with its rigid fused-ring skeleton, endows the resin with excellent thermal stability, allowing it to maintain structural integrity under high-temperature conditions and significantly improving its resistance to plasma etching. Monomer II, through polycondensation, incorporates its aryl and alkyl groups into the main chain, maintaining the rigidity of the skeleton while providing appropriate flexibility to the molecular chain, thereby improving the film-forming quality and mechanical extensibility of the resin and effectively preventing brittleness of the coating during processing. Furthermore, by introducing functional residues at the ortho positions of the hydroxyl groups of the dibenzo-dioxin structural units using electrophilic reagents, the resin's solubility in alkaline developing solutions and its affinity with the substrate interface can be adjusted. This also provides more active sites for interaction with photosensitizers. Thus, the provided resin, with the synergistic effect of a rigid skeleton providing stable support and connecting units imparting mechanical compliance and film-forming properties, possesses excellent thermal stability, mechanical properties, and etching resistance.

[0009] In some embodiments of the present invention, the phenolic prepolymer has the structural unit shown in Formula 1a:

[0010] In some embodiments of the present invention, the weight-average molecular weight of the phenolic prepolymer is 800-1500.

[0011] In some embodiments of the present invention, the photosensitive resin has a weight-average molecular weight of 6,500 to 15,000 and a molecular weight distribution index of 1.30 to 2.50.

[0012] In a second aspect, the present invention provides a method for preparing the photosensitive resin described in the first aspect of the present invention, comprising the following steps: (1) Under the protection of an inert gas, monomer I and monomer II undergo a polycondensation reaction in the presence of an acid catalyst and a first solvent to form the phenolic prepolymer; (2) Add the electrophilic reagent to the system obtained in step (1) to carry out an electrophilic substitution reaction to form the photosensitive resin.

[0013] In some embodiments of the present invention, in step (1), the molar ratio of monomer I to monomer II is (1.8~4):1.

[0014] In some embodiments of the present invention, the amount of electrophilic reagent used in step (2) is 0.2 to 0.8 mol relative to 1 mol of monomer I.

[0015] Thirdly, the present invention provides a photosensitive resin composition comprising a matrix resin, a photosensitizer, a second solvent, and a crosslinking agent; wherein the matrix resin is the photosensitive resin described in the first aspect of the present invention.

[0016] In some embodiments of the present invention, the photosensitizer is a photosensitive diazonium compound. The imaging of this composition is based on the synergistic effect of dissolution inhibition and photodecomposition. In the unexposed area, the diazonium group forms intermolecular hydrogen bonds with the phenolic hydroxyl group, inhibiting the dissolution of the resin in the alkaline developer; in the exposed area, the diazonium compound is converted into hydrophilic indene carboxylic acid, destroying the inhibition structure and generating a carboxyl group readily soluble in alkali. Simultaneously, the released phenolic hydroxyl group can also participate in the reaction, causing the exposed area to dissolve rapidly, forming a positive pattern.

[0017] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Detailed Implementation

[0018] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0019] The "scope" disclosed in this invention is defined in the form of a lower limit and / or an upper limit, whereby a given scope is defined by selecting a lower limit and / or an upper limit. This scope may or may not include endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form an undefined scope, and any lower limit can be combined with other lower limits to form an undefined scope, similarly, any upper limit can be combined with any other upper limit to form an undefined scope. Furthermore, each individually disclosed point or single value can itself serve as a lower or upper limit and can be combined with any other point or single value, or with other lower or upper limits, to form an undefined scope.

[0020] It should be noted that in this invention, the terms "first" and "second" and the expressions "××I" and "××II" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0021] Unless otherwise specified, all embodiments and optional embodiments of the present invention may be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present invention.

[0022] A first aspect of the present invention provides a photosensitive resin. The photosensitive resin is a modified phenolic resin and is formed by an electrophilic substitution reaction between a phenolic prepolymer and an electrophilic reagent.

[0023] In this invention, the phenolic prepolymer is formed by a polycondensation reaction of monomer I with the structure shown in Formula 1 and monomer II with the structure shown in Formula 2.

[0024] In Equation 1, m and n each independently represent 1 or 2; In Formula 2, Ar is an aryl group with 6 to 18 carbon atoms.

[0025] In this invention, monomer I has a reactive site at the ortho position of the hydroxyl group on its benzene ring. This reactive site undergoes a condensation reaction with the hydroxymethyl group (-CH2OH) in monomer II, removing one molecule of water and causing the structural units provided by monomer I and monomer II to bond together, forming the phenolic prepolymer. Specifically, the phenolic prepolymer may have the following structure:

[0026] Where p represents the degree of polymerization, and p≥2. The non-directed linkages in the structural formula indicate that the structural unit of monomer II is bonded to the benzene ring of monomer I through a condensation reaction; given the directing effect of phenolic condensation polymerization, the specific linkage sites are mainly ortho-positions of hydroxyl groups, and may include a small number of para-position linkages.

[0027] In some embodiments, the weight-average molecular weight of the phenolic prepolymer is 800-1500, such as 820, 850, 900, 1100, 1200, 1300, etc.

[0028] As some specific examples, in the monomer I shown in Equation 1, m=1 and n=1, or m=2 and n=2.

[0029] In some embodiments, monomer I is at least one of compound C1 (dibenzo[b,e][1,4]dioxin-2,8-diol, CAS: 775537-59-2), compound C2 (1,3,6,8-tetrahydroxydibenzo[b,e][1,4]dioxin, CAS: 121449-71-6), and compound C3 (1,3,7,9-tetrahydroxydibenzo[b,e][1,4]dioxin, CAS: 1323436-22-1).

[0030] As specific examples, in monomer II shown in Formula 2, Ar is phenylene, naphthylene, or biphenylene. Preferably, Ar is naphthylene, and accordingly, the resulting phenolic prepolymer has repeating units as shown in Formula 1a:

[0031] In some embodiments, monomer II is selected from at least one of 2,6-bis(hydroxymethyl)naphthalene, 1,5-bis(hydroxymethyl)naphthalene, 2,3-bis(hydroxymethyl)naphthalene, and 1,8-bis(hydroxymethyl)naphthalene. Preferably, monomer II is 2,6-bis(hydroxymethyl)naphthalene and / or 1,5-bis(hydroxymethyl)naphthalene.

[0032] As some specific examples, the phenolic prepolymer has at least one of the following structures:

[0033] In this invention, the electrophilic agent is an aldehyde compound and / or a polymethoxymethyl compound. In the prepolymer, the unsubstituted sites (sites not connected to the structural unit of monomer II) in the structural unit provided by monomer I react with the aldehyde or methoxymethyl group provided by the electrophilic agent, removing small molecules, thereby bonding the electrophilic agent with the structure provided by monomer I, further extending the chain of the prepolymer to form the photosensitive resin. Exemplarily, the chain segment formed by the bonding of the structure provided by monomer I with the electrophilic agent may include the structure shown in Formula 1b:

[0034] Here, A represents the residue of the electrophilic reagent.

[0035] In this invention, the aldehyde compound refers to a compound having an aldehyde group, which can be an aliphatic aldehyde or an aromatic aldehyde. According to some embodiments, the aldehyde compound has the general formula shown in Formula 3-1: RLC(O) Equation 3-1, Wherein, R represents hydrogen, an alkyl group with 1 to 8 carbon atoms, an aryl group with 6 to 18 carbon atoms, an aralkyl group with 7 to 18 carbon atoms, a carboxyl group, a 5 to 10-membered cycloalkyl group, or a 5 to 10-membered cycloalkenyl group, and L represents a single bond or an alkenyl group with 2 to 4 carbon atoms. When aldehyde compounds satisfy the general formula shown in Formula 3-1, the residue represented by A is -CH(LR)-.

[0036] As examples, the aldehyde compounds are selected from at least one of formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, pentanaldehyde, and hexanal.

[0037] In this invention, the polymethoxymethyl compound refers to a compound having at least two methoxymethyl groups (-CH2OCH3), preferably a dimethoxymethyl compound, and the compound can be an aliphatic compound or an aromatic compound. According to some embodiments, the polymethoxymethyl compound has the general formula shown in Formula 3-2: CH3OCH2-L1-CH2OCH3 (Formula 3-2) Wherein, L1 is selected from alkylene groups having 1 to 6 carbon atoms, substituted or unsubstituted aryl groups having 6 to 12 carbon atoms, or -Ph-O-Ph, wherein there are one or more substituents, and the substituents are alkyl groups having 1 to 4 carbon atoms, such as methyl or ethyl. When the polymethoxymethyl compound satisfies the general formula shown in Formula 3-2, the residue represented by A is -CH2-L1-CH2-.

[0038] As examples, the polymethoxymethyl compound is selected from at least one of 1,5-dimethoxypentane, 1,4-bis(methoxymethyl)benzene, 1,3-bis(methoxymethyl)benzene, 4,4'-bis(methoxymethyl)diphenyl ether, and 1,4-bis(methoxymethyl)-2,3,5,6-tetramethylbenzene (CAS: 1424-78-8).

[0039] In some embodiments, the weight-average molecular weight of the photosensitive resin can be 6000-15000, for example 6500, 6800, 7000, 7400, 7800, 8000, 8500, 8840, 9000, 9200, 9600, 10000, 11550, 12000, 15000, etc.; the molecular weight distribution index (PDI) can be 1.30-2.50, for example 1.30, 1.43, 1.65, 1.70, 1.82, 1.85, 1.92, 2.05, 2.20, 2.31, 2.35, 2.40, etc. The amount and distribution of the resin can be determined by gel permeation chromatography (GPC).

[0040] A second aspect of the present invention provides a method for preparing the photosensitive resin described in the first aspect of the present invention, the method comprising the following steps: (1) Under the protection of an inert gas, monomer I and monomer II undergo a polycondensation reaction in the presence of a catalyst and a first solvent to form the phenolic prepolymer; (2) Add the electrophilic reagent to the system obtained in step (1) to carry out an electrophilic substitution reaction to form the photosensitive resin.

[0041] In step (1), the molar ratio of monomer I to monomer II can be (1.8~4)∶1, for example 1.8∶1, 1.9∶1, 2∶1, 2.5∶1, 2.8∶1, 3∶1, 3.5∶1, 4∶1, etc.

[0042] In some embodiments, the temperature of the polycondensation reaction can be 100~150℃, such as 100℃, 105℃, 110℃, 120℃, 130℃, 135℃, 145℃, etc.; the reaction time can be 4~12h, such as 4h, 4.5h, 5h, 6h, 8h, 10h, 12h, etc.

[0043] In step (1), the polycondensation reaction is carried out in the presence of a first solvent. The present invention does not particularly limit the first solvent, as long as it allows all components to dissolve. As some examples, the first solvent is selected from at least one of propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), γ-butyrolactone, methyl lactate, ethyl lactate, butyl lactate, N-methyl-2-pyrrolidone, ethyl acetate, cyclopentanone, and cyclohexanone.

[0044] In some embodiments, the mass ratio of the first solvent to the total amount of monomer I and monomer II can be 10:(5~10), for example 10:5, 10:6, 10:7.5, 10:9, 10:10, etc.

[0045] In step (1), the polycondensation reaction is typically carried out in the presence of an acid catalyst. The catalyst may be an acid catalyst, and specific examples include, but are not limited to, one or more of p-benzenesulfonic acid, formic acid, oxalic acid, benzoic acid, salicylic acid, sulfuric acid, phosphoric acid, perchloric acid, nitric acid, hydrochloric acid, and acidic ion exchange resins. According to some preferred examples, the acid catalyst is selected from hydrochloric acid, benzoic acid, p-toluenesulfonic acid, oxalic acid, and acidic ion exchange resins.

[0046] In some embodiments, the mass amount of the acid catalyst is 0.1% to 2% of the total mass of monomer I and monomer II, for example, 0.2%, 0.3%, 0.4%, 0.5%, 0.7%, 1%, 1.2%, 1.3%, 1.5%, etc.

[0047] In step (2), the amount of the electrophilic reagent can be selected, for example, based on the amount of monomer I used in step (1). According to some embodiments, the amount of the electrophilic reagent is 0.2 to 0.8 mol relative to 1 mol of monomer I, for example, 0.3 mol, 0.4 mol, 0.5 mol, 0.6 mol, 0.8 mol, etc.

[0048] In step (2), the temperature of the electrophilic substitution reaction can be 50~130℃, for example 80℃, 90℃, 95℃, 100℃, 115℃, 120℃, etc.; the reaction time is 1~20h, for example 2h, 2.5h, 3h, 4h, 5h, 6h, 7h, 8h, 10h, 12h, 15h, 20h, etc. As some examples, the electrophilic reagent is an aldehyde compound, the temperature of the electrophilic substitution reaction is 60~120℃, for example 70℃, 80℃, 95℃, 100℃, 110℃, 120℃, etc., and the reaction time is 10~20h, for example 10h, 12h, 15h, 16h, 18h, etc. As other examples, the electrophilic reagent is a polymethoxymethyl compound, the electrophilic substitution reaction temperature is 60~80℃, for example 60℃, 65℃, 70℃, 80℃, etc., and the reaction time is 1~6h, for example 2h, 4h, 5h, 6h, etc.

[0049] To further obtain a high-purity dried resin product, the method preferably further includes: (3) Under stirring conditions, the first solvent is added to the reaction solution obtained in step (2) for dilution to obtain a diluted reaction solution. Water is then added to precipitate the resin, which is then recovered. After washing with water, dehydration, and vacuum drying, the resin product is obtained. The first solvent used for dilution can be 2 to 5 times the amount of the first solvent used in step (1). The amount of water used can be 10 to 30 times the total volume of the first solvent used in steps (1) and (3).

[0050] A third aspect of the present invention provides a photosensitive resin composition comprising a matrix resin, a photosensitizer, a second solvent, and a crosslinking agent.

[0051] In this invention, the matrix resin is the photosensitive resin described in the first aspect of this invention. According to some embodiments, based on the total weight of the photosensitive resin composition, the mass content of the matrix resin can be 25% to 45%, for example, 25%, 27%, 30%, 33%, 35%, 40%, 45%, etc.

[0052] In this invention, the photosensitizer can be a diazononaphthoquinone compound, preferably at least one of 2,3,4-trihydroxybenzophenone-1,2-diazonaphthoquinone-5-sulfonate (CAS: 68510-93-0) and compounds with the following structures:

[0053] Wherein, D can be H or a group with the structure shown below:

[0054] Furthermore, in Equations 4-1 to 4-3, D shown in each structural formula is not simultaneously H.

[0055] In some embodiments, the mass content of the photosensitizer can be 1% to 5% based on the total weight of the photosensitive resin composition, for example, 1%, 1.3%, 1.5%, 2%, 3%, 3.5%, 4%, 4.5%, 5%, etc.

[0056] In this invention, the crosslinking agent can be, for example, a melamine compound and / or a glycourea compound. Further, specific examples of melamine compounds include, but are not limited to, one or more of hexamethoxymethylmelamine, hexahydroxymethylmelamine, and hexaethoxymethylmelamine. Specific examples of glycourea compounds include, but are not limited to, tetramethoxymethylglycourea and / or N,N'-bis(methoxymethyl)urea. During the heat treatment after development, the multifunctional active groups provided by the crosslinking agent can undergo a crosslinking reaction with the phenolic hydroxyl groups in the matrix resin to form a three-dimensional network structure.

[0057] In some embodiments, the mass content of the crosslinking agent can be 0.1% to 2%, for example, 0.1%, 0.3%, 0.5%, 0.8%, 1%, 1.5%, etc., based on the total weight of the photosensitive resin composition.

[0058] The present invention does not particularly limit the second solvent used in the composition, as long as it can dissolve the other components in the composition, so that the composition is in a solution state. Specific examples of the second solvent are, but are not limited to, one or more of the following solvents: propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, γ-butyrolactone, methyl lactate, ethyl lactate, butyl lactate, N-methyl-2-pyrrolidone, ethyl acetate, cyclopentanone, and cyclohexanone.

[0059] In some embodiments, the mass content of the second solvent can be 50% to 70% based on the total weight of the photosensitive resin composition, for example, 50%, 52%, 55%, 60%, 62%, 65%, 68%, 70%, etc.

[0060] In this invention, the matrix resin, photosensitizer, second solvent, and optional crosslinking agent can be mixed evenly and then filtered to obtain a photosensitive resin composition.

[0061] In this invention, the photosensitive resin is used to form a photosensitive resin layer, which is typically prepared by applying the composition to a substrate and then performing steps such as coating, pre-baking, exposure, curing, and optionally development. As some specific examples, the method for preparing the photosensitive resin layer includes: The photosensitive resin composition is coated on the surface of a substrate and pre-baked at 80~120°C for 1~10 min to remove the second solvent and form a solid photosensitive film. Selective ultraviolet irradiation can be performed, with an exposure dose of 30~200 mJ / cm². 2 ; Finally, heat-curing at 100~250℃ for 30~120 minutes forms a photosensitive resin layer.

[0062] The following describes embodiments of the present invention. These embodiments are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0063] The following preparation examples are used in the photosensitive resin and preparation method of the present invention.

[0064] Preparation Example 1 (1) Dibenzo[b,e][1,4]dioxin-2,8-diol (108.10 g, 0.50 mol), 2,6-bis(hydroxymethyl)naphthalene (40.8 g, 0.21 mol), and 1.5 g of p-toluenesulfonic acid were added to a reaction flask equipped with a mechanical stirrer, thermometer, reflux condenser, water separator, and nitrogen inlet. Then, 120 mL of propylene glycol monomethyl ether (PGME) was added and stirred until the raw materials were dissolved. Under nitrogen protection, the mixture was heated to 130 °C and stirred for 8 h. During the reaction, the generated water was separated by the water separator. After the reaction was completed, a prepolymer with repeating units as shown in Formula 1a-1 was obtained. According to GPC testing, the Mw of the prepolymer was 850.

[0065] (2) Add 1,5-dimethoxypentane (26.44 g, 0.20 mol) to the system obtained in step (1). Under nitrogen protection, stir the mixture at 60 °C for 6 h. After the reaction is complete, cool the system to room temperature and dilute the reaction product with 350 mL of PGME to obtain a diluted reaction solution. Under high-speed stirring, add the diluted reaction solution dropwise to 10 L of water to disperse and precipitate the resin for recovery. Wash and dehydrate the precipitated resin with water, and finally dry it under vacuum to obtain photosensitive resin P1. According to GPC testing, resin P1 has Mw = 7400 and PDI = 2.15.

[0066] Preparation Example 2 (1) In a reaction flask equipped with a mechanical stirrer, thermometer, reflux condenser, water separator, and nitrogen inlet, add dibenzo[b,e][1,4]dioxin-2,8-diol (108.1 g, 0.50 mol), 2,6-bis(hydroxymethyl)naphthalene (40.8 g, 0.21 mol), and 1.5 g of p-toluenesulfonic acid, then add 120 mL of PGME and stir until the raw materials are dissolved. Under nitrogen protection, heat to 130 °C and stir for 8 h. During this period, separate the generated water using a water separator. After the reaction is complete, the prepolymer is obtained.

[0067] (2) Add 1,4-di(methoxymethyl)-2,3,5,6-tetramethylbenzene (44.46 g, 0.20 mol) to the system obtained in step (1). Under nitrogen protection, stir the reaction at 65 °C for 6 h. After the reaction is complete, cool the system to room temperature and dilute the reaction product with 370 mL of PGME to obtain a diluted reaction solution. Under high-speed stirring, add the above diluted reaction solution dropwise to 10 L of water to disperse and precipitate the resin for recovery. Wash the precipitated resin with water, dehydrate it, and then vacuum dry it to obtain photosensitive resin P2. According to GPC testing, resin P2 has Mw = 8500 and PDI = 1.85.

[0068] Preparation Example 3 (1) In a reaction flask equipped with a mechanical stirrer, thermometer, reflux condenser, water separator, and nitrogen inlet, 1,3,7,9-tetrahydroxydibenzo[b,e][1,4]dioxin (124.1 g, 0.50 mol), 2,6-bis(hydroxymethyl)naphthalene (40.8 g, 0.21 mol), and 1.6 g of p-toluenesulfonic acid were added, and 120 mL of PGME was added and stirred until the raw materials dissolved. Under nitrogen protection, the mixture was heated to 140 °C and stirred for 8 h. During the reaction, the generated water was separated by a water separator. After the reaction was completed, a prepolymer with repeating units as shown in Formula 1a-2 was obtained. According to GPC testing, the Mw of the prepolymer was 945.

[0069] (2) Add 1,4-di(methoxymethyl)-2,3,5,6-tetramethylbenzene (44.46 g, 0.20 mol) to the system obtained in step (1). Under nitrogen protection, stir the mixture at 80 °C for 6 h. After the reaction is complete, cool the system to room temperature and dilute the reaction product with 350 g of PGME to obtain a diluted reaction solution. Under high-speed stirring, add the diluted reaction solution dropwise to 10 L of water to disperse and precipitate the resin for recovery. Wash the precipitated resin with water, dehydrate it, and then vacuum dry it to obtain photosensitive resin P3. According to GPC testing, resin P3 has Mw = 6860 and PDI = 2.20.

[0070] Preparation Example 4 (1) In a reaction flask equipped with a mechanical stirrer, thermometer, reflux condenser, water separator, and nitrogen inlet, 1,3,7,9-tetrahydroxydibenzo[b,e][1,4]dioxin (124.1 g, 0.50 mol), 1,5-bis(hydroxymethyl)naphthalene (37.6 g, 0.20 mol), and 1.6 g of p-toluenesulfonic acid were added, followed by the addition of 120 mL of PGME and stirring until the raw materials dissolved. Under nitrogen protection, the mixture was heated to 130 °C and stirred for 8 h. During the reaction, the generated water was separated using a water separator. After the reaction was completed, a prepolymer with repeating units as shown in Formula 1a-4 was obtained. According to GPC testing, the Mw of the prepolymer was 1100.

[0071] (2) Add 1,4-di(methoxymethyl)-2,3,5,6-tetramethylbenzene (44.46 g, 0.2 mol) to the system obtained in step (1). Under nitrogen protection, stir the mixture at 60 °C for 6 h. After the reaction is complete, cool the system to room temperature and dilute the reaction product with 350 mL of PGME to obtain a diluted reaction solution. Under high-speed stirring, add the diluted reaction solution dropwise to 10 L of water to disperse and precipitate the resin for recovery. Wash the precipitated resin with water, dehydrate it, and then vacuum dry it to obtain photosensitive resin P4. P4 has Mw = 9200 and PDI = 1.82.

[0072] Preparation Example 5 (1) 1,3,6,8-tetrahydroxydibenzo[b,e][1,4]dioxin (124.1 g, 0.50 mol) and 1,5-bis(hydroxymethyl)naphthalene (37.6 g, 0.20 mol) were added to a reaction flask equipped with a mechanical stirrer, thermometer, reflux condenser, water separator, and nitrogen inlet pipe. Then 1.6 g of p-toluenesulfonic acid and 120 mL of propylene glycol monomethyl ether were added. The mixture was heated to 130 °C under continuous nitrogen protection and stirred for 8 h. During the reaction, the generated water was separated by the water separator. After the reaction was completed, a prepolymer with repeating units as shown in Formula 1a-6 was obtained. GPC test showed that the Mw of the prepolymer was 1040.

[0073] (2) Add 4,4'-di(methoxymethyl)diphenyl ether (51.66 g, 0.20 mol) to the system obtained in step (1), and stir the mixture at 60 °C for 4 h under nitrogen protection. After the reaction is complete, cool the system to room temperature, and then dilute the reaction product with 400 mL of PGME to obtain a diluted reaction solution. Under high-speed stirring, add the above diluted reaction solution dropwise to 10 L of water to disperse and precipitate the resin for recovery. Wash and dehydrate the precipitated resin with water, and finally dry it under vacuum to obtain a photosensitive resin with Mw = 8840 and PDI = 2.31 for P5.

[0074] Preparation Example 6 (1) In a reaction flask equipped with a mechanical stirrer, thermometer, reflux condenser, water separator, and nitrogen inlet, add dibenzo[b,e][1,4]dioxin-2,8-diol (108.1 g, 0.50 mol), 2,6-bis(hydroxymethyl)naphthalene (40.8 g, 0.21 mol), and 1.5 g of p-toluenesulfonic acid, then add 120 mL of PGME and stir until the raw materials are dissolved. Under nitrogen protection, heat to 130 °C and stir for 8 h. During this period, separate the generated water using a water separator. After the reaction is complete, the prepolymer is obtained.

[0075] (2) Add 37wt% formaldehyde solution (9.8g, 0.12mol) to the system obtained in step (1). Under nitrogen protection, stir and react at 100℃ for 16h. After the reaction is complete, cool the system to room temperature and dilute the reaction product with 370mL PGME to obtain a diluted reaction solution. Under high-speed stirring, add the above diluted reaction solution dropwise to 10L of water to disperse and precipitate the resin for recovery. Wash the precipitated resin with water, dehydrate it, and then vacuum dry it to obtain photosensitive resin P6. According to GPC testing, resin P6 has Mw=9450 and PDI=2.12.

[0076] Preparation Example 7 (1) In a reaction flask equipped with a mechanical stirrer, thermometer, reflux condenser, water separator, and nitrogen inlet, add dibenzo[b,e][1,4]dioxin-2,8-diol (108.1 g, 0.50 mol), 2,6-bis(hydroxymethyl)naphthalene (40.8 g, 0.21 mol), and 1.5 g of p-toluenesulfonic acid, then add 120 mL of PGME and stir until the raw materials are dissolved. Under nitrogen protection, heat to 130 °C and stir for 8 h. During this period, separate the generated water using a water separator. After the reaction is complete, the prepolymer is obtained.

[0077] (2) Benzaldehyde (31.8 g, 0.30 mol) was added to the system obtained in step (1). Under nitrogen protection, the mixture was stirred at 110 °C for 12 h. After the reaction was completed, the system was cooled to room temperature, and the reaction product was diluted with 370 mL of PGME to obtain a diluted reaction solution. Under high-speed stirring, the diluted reaction solution was added dropwise to 10 L of water to disperse and precipitate the resin for recovery. The precipitated resin was washed with water, dehydrated, and then vacuum dried to obtain photosensitive resin P7. According to GPC testing, resin P7 has Mw = 10220 and PDI = 2.15.

[0078] Comparative Preparation Example 1 In a reaction flask equipped with a mechanical stirrer, thermometer, reflux condenser, water separator, and nitrogen inlet tube, resorcinol (13.2 g, 0.12 mol), PGME 180 mL, 37 wt% formaldehyde solution (9.8 g, 0.12 mol), and 0.23 g p-toluenesulfonic acid were added and stirred until homogeneous. Under nitrogen protection, the temperature was raised to 120 °C and the reaction was stirred for 6 h. After the reaction was completed, the reaction product was diluted with 300 mL of PGME to obtain a diluted reaction solution. Under high-speed stirring, the diluted reaction solution was added dropwise to 9 L of water to disperse and precipitate the resin for recovery. The precipitated resin was washed and dehydrated, and finally dried under vacuum to obtain phenolic photosensitive resin R1. Resin R1 has a Mw of 8400 and a PDI of 2.13.

[0079] Comparative Preparation Example 2 (1) Resorcinol (55.06 g, 0.50 mol), 2,6-bis(hydroxymethyl)naphthalene (40.8 g, 0.21 mol), and 1.0 g p-toluenesulfonic acid were added to a reaction flask equipped with a mechanical stirrer, thermometer, reflux condenser, water separator, and nitrogen inlet tube. Then, 120 mL of PGME was added and stirred until the raw materials were dissolved. Under nitrogen protection, the mixture was heated to 130 °C and stirred for 8 h. During the reaction, the generated water was separated by the water separator. After the reaction was completed, the prepolymer was obtained.

[0080] (2) Add 1,5-dimethoxypentane (26.44 g, 0.2 mol) to the system obtained in step (1). Under nitrogen protection, stir the mixture at 100 °C for 6 h. After the reaction is complete, cool the system to room temperature and add 350 mL of PGME to dilute the reaction product to obtain a diluted reaction solution. Under high-speed stirring, add the above diluted reaction solution dropwise to 10 L of water to disperse and precipitate the resin for recovery. Wash and dehydrate the precipitated resin with water, and finally dry it under vacuum to obtain photosensitive resin R2. R2 has Mw = 8260 and PDI = 1.75.

[0081] Comparative preparation example 3 In a four-necked flask equipped with a mechanical stirrer, thermometer, reflux condenser, and nitrogen inlet, dibenzo[b,e][1,4]dioxin-2,8-diol (108.1 g, 0.50 mol), 2,6-bis(hydroxymethyl)naphthalene (40.8 g, 0.21 mol), and 1.5 g of p-toluenesulfonic acid were added, followed by 120 mL of PGME and stirred until homogeneous. Under nitrogen protection, the temperature was raised to 130 °C and the reaction was stirred for 8 h. During the reaction, water generated was separated using a water separator. After the reaction was completed, the mixture was cooled to room temperature to obtain the reaction product. The reaction product was then diluted with 350 mL of PGME to obtain a diluted reaction solution. Under high-speed stirring, the diluted reaction solution was added dropwise to 10 L of water to disperse and precipitate the resin for recovery. The precipitated resin was washed with water, dehydrated, and then vacuum dried to obtain phenolic photosensitive resin R3.

[0082] The following examples illustrate the photosensitive resin composition prepared using the above-described resin product.

[0083] Example 1 Weigh 35 parts by weight of photosensitive resin P1, 2 parts by weight of 2,3,4-trihydroxybenzophenone-1,2-diazonaphthoquinone-5-sulfonate, 1 part by weight of tetramethoxymethyl glycourea and 62 parts by weight of propylene glycol monomethyl ether, mix them evenly, and then filter them through a 0.22 μm filter to obtain the photosensitive resin composition.

[0084] Examples 2-7 The photosensitive resin composition was prepared according to the method of Example 1, except that resin P1 was replaced with resins P2 to P7 respectively.

[0085] Comparative Examples 1-3 The photosensitive resin composition was prepared according to the method of Example 1, except that resin P1 was replaced with resins R1 to R3 respectively.

[0086] Test case This test example is used to evaluate the performance of the photosensitive resin compositions prepared in the above examples and comparative examples.

[0087] (1) Etching resistance test The photosensitive resin composition was spin-coated onto silicon wafers, pre-baked at 120°C for 1 minute, and then exposed at an energy of 50 mJ / cm². 2After exposure, the wafer was placed on a hot plate and cured at 200°C for 10 minutes to form a cured film. The film thickness was measured using a thin film thickness meter manufactured by K-MAC. Subsequently, the sample was placed in an etching apparatus, and etching was performed using a CHF3 / CF4 mixed gas (volume flow ratio of 1:1, total flow rate of 100 sccm) as the etching gas for 60 seconds. After etching, the film thickness was measured again, and the etching rate was calculated using the following formula.

[0088] Etching rate = (Initial thickness of hard mask - Film thickness after etching) / Etching time (2) Heat resistance test The photosensitive resin composition was spin-coated onto silicon wafers, pre-baked at 120°C for 1 minute, and then exposed at an energy of 50 mJ / cm². 2 After exposure, the wafer is placed on a hot plate and cured at 200°C for 10 minutes to form a cured film.

[0089] The cured film is scraped off the silicon wafer and collected to obtain a powdered sample for testing.

[0090] The samples were tested using a differential scanning calorimeter (DSC). Under a nitrogen atmosphere, the temperature was increased from room temperature to 340℃ at a rate of 10℃ / min, and the DSC curve was recorded. The temperature at the inflection point of the curve was recorded as Tg.

[0091] Samples were tested using a thermogravimetric analyzer (TGA). Under a nitrogen atmosphere, the temperature was increased from room temperature to 500℃ at a rate of 10℃ / min, and the thermogravimetric curves were recorded. The temperature at which the sample weight loss was 5% was taken as Td.

[0092] (3) Mechanical strength test The photosensitive resin composition was coated onto silicon wafers using a doctor blade coater, pre-baked at 120°C for 1 minute, and then exposed at an exposure energy of 50 mJ / cm². 2 After exposure, the wafer is placed on a hot plate and cured at 200°C for 10 minutes to form a cured film with a thickness of 1 mm.

[0093] The silicon wafer with the cured film was immersed in a dilute hydrochloric acid aqueous solution (concentration 5wt%). The hydrochloric acid was used to erode the substrate interface layer, so that the cured film was completely peeled off from the wafer. The film sample was taken out, washed with deionized water and dried to obtain the film sample to be tested.

[0094] The tensile strength and elongation at break of the membrane samples were tested according to GB / T 1040.3-2006.

[0095] The test results are shown in Table 1.

[0096] Table 1

[0097] As shown in Table 1, compared to Comparative Examples 1-3, Examples 1-7 exhibited lower etching rates and higher glass transition temperature (Tg) and thermal decomposition temperature (Td), indicating that the cured materials formed from the photosensitive resin compositions of Examples 1-7 possess superior etching resistance and heat resistance. Furthermore, the tensile strength and elongation at break of Examples 1-7 were significantly better than those of Comparative Examples 1-3, demonstrating that the cured films formed from Examples 1-7 possess both high strength and high toughness. Additionally, tensile strength reflects a material's resistance to breakage, while elongation at break reflects its toughness; high tensile strength in both cases indicates high toughness. Therefore, the cured materials formed from the photosensitive resin compositions of Examples 1-7 maintain good etching resistance and thermal stability while also exhibiting excellent mechanical properties, which is beneficial for meeting the high precision and high reliability requirements of hard mask materials in semiconductor processing.

[0098] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A photosensitive resin, characterized in that, Formed by electrophilic substitution reaction of phenolic prepolymer and electrophilic reagent, wherein the phenolic prepolymer is formed by polycondensation reaction of monomer I with structure as shown in Formula 1 and monomer II with structure as shown in Formula 2. In Equation 1, m and n each independently represent 1 or 2; in Equation 2, Ar is an aryl group with 6 to 18 carbon atoms. The electrophilic reagent is an aldehyde compound and / or a polymethoxymethyl compound.

2. The photosensitive resin according to claim 1, characterized in that, The phenolic prepolymer has repeating units as shown in Formula 1a: in," " indicates a connection key.

3. The photosensitive resin according to claim 1 or 2, characterized in that, The monomer I is at least one of compound C1, compound C2 and compound C3: Preferably, monomer II is selected from at least one of 2,6-bis(hydroxymethyl)naphthalene, 1,5-bis(hydroxymethyl)naphthalene, 2,3-bis(hydroxymethyl)naphthalene, and 1,8-bis(hydroxymethyl)naphthalene; Preferably, the weight-average molecular weight of the phenolic prepolymer is 800-1500.

4. The photosensitive resin according to any one of claims 1-3, characterized in that, The aldehyde compounds are selected from at least one of formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde, and hexanal; Preferably, the polymethoxymethyl compound is selected from at least one of 1,5-dimethoxypentane, 1,4-bis(methoxymethyl)benzene, 1,3-bis(methoxymethyl)benzene, 4,4'-bis(methoxymethyl)diphenyl ether and 1,4-bis(methoxymethyl)-2,3,5,6-tetramethylbenzene.

5. The photosensitive resin according to any one of claims 1-4, characterized in that, The photosensitive resin has a weight-average molecular weight of 6,000 to 15,000 and a molecular weight distribution index of 1.30 to 2.

50.

6. A method for preparing the photosensitive resin according to any one of claims 1-5, characterized in that, Includes the following steps: (1) Under the protection of an inert gas, monomer I and monomer II undergo a polycondensation reaction in the presence of an acid catalyst and a first solvent to form the phenolic prepolymer; (2) Add the electrophilic reagent to the system obtained in step (1) to carry out an electrophilic substitution reaction to form the photosensitive resin.

7. The method according to claim 6, characterized in that, In step (1), the molar ratio of monomer I to monomer II is (1.8~4):1; Preferably, the polycondensation reaction is carried out at a temperature of 100-150°C for 4-12 hours. Preferably, the acid catalyst is selected from at least one of hydrochloric acid, benzoic acid, p-toluenesulfonic acid, oxalic acid, and acidic ion exchange resin; Preferably, the acid catalyst accounts for 0.1% to 2% of the total weight of monomer I and monomer II.

8. The method according to claim 6 or 7, characterized in that, The amount of electrophilic reagent used in step (2) is 0.2~0.8 mol relative to 1 mol of monomer I; Preferably, the electrophilic substitution reaction is carried out at a temperature of 50-130°C for 1-20 hours.

9. A photosensitive resin composition, characterized in that, It comprises a matrix resin, a photosensitizer, a second solvent, and a crosslinking agent; wherein the matrix resin is the photosensitive resin according to any one of claims 1-5.

10. The photosensitive resin composition according to claim 9, characterized in that, The photosensitizer is a diazononaphthoquinone compound; Preferably, based on the total weight of the photosensitive resin composition, the mass content of the matrix resin is 25% to 45%, the mass content of the photosensitizer is 1% to 5%, the mass content of the second solvent is 50% to 70%, and the mass content of the crosslinking agent is 0.1% to 2%.

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