Polyphenol compound, method for producing the same, epoxy resin, and photoresist composition thereof

Abstract

This disclosure provides a polyphenol compound and its preparation method, as well as an epoxy resin and its photoresist composition, which can be applied to the fields of micro-nano fabrication and photoresist technology. The polyphenol compound is composed of multiple phenol structural units alternately linked with methylene groups, each phenol structural unit having 1 to 3 substituents selected from C1 to C6. 10 One or more of alkyl, alkoxy, ester, ether, aryl, cyano, or halogen groups are used. The molecular chain length can be precisely controlled through a hydroxymethylation-condensation cycle reaction to obtain polyphenol compounds with a uniform molecular weight distribution. This polyphenol compound is reacted with an epoxy haloalkane to prepare an epoxy resin, which is further compounded with a photoacid generator and a solvent to form an epoxy negative photoresist composition. This photoresist composition significantly improves sensitivity, resolution, and process adaptability.

Description

Technical Field

[0001] This disclosure relates to the fields of micro / nano fabrication and photoresist technology, and more specifically to a polyphenol compound and its preparation method, an epoxy resin and its photoresist composition. Background Technology

[0002] In patterning processes for semiconductor manufacturing, microelectromechanical systems (MEMS) packaging, microfluidic chips, and advanced packaging, negative photoresists play a crucial role due to their process stability and excellent substrate adhesion. Among them, epoxy resin-based negative photoresists have become key materials for fabricating microstructures with high aspect ratios, high mechanical strength, and excellent chemical stability since their introduction.

[0003] The main advantages of epoxy negative photoresists include: after exposure, the epoxy resin undergoes cationic ring-opening polymerization under the action of a photoacid-generating agent, forming a highly cross-linked three-dimensional network structure, which, after curing, has extremely high mechanical strength, excellent thermal stability, and outstanding chemical corrosion resistance, making it suitable as a permanent microstructure or protective layer; at the same time, epoxy negative photoresists usually have high viscosity and solid content, which can obtain thicker films through a single spin coating, and their high quantum efficiency and high cross-linking density of photochemical reactions enable the achievement of high aspect ratio patterns with steep sidewalls under ultraviolet or electron beam exposure.

[0004] However, existing epoxy negative photoresists still have the following technical drawbacks when applied to high-resolution photolithography processes:

[0005] First, there is a trade-off between exposure sensitivity and processing efficiency. The exposure dose required to achieve full crosslinking is typically high, especially in thick adhesive applications or when using UV light sources with weak penetration. This high dose requirement leads to low production efficiency and limited equipment throughput. In direct writing processes such as electron beam lithography, the high dose requirement severely impacts processing efficiency and increases manufacturing costs.

[0006] Second, resolution limitations and pattern quality issues are prominent. The chemical amplification reaction and cross-linking process of epoxy negative photoresists may cause lateral diffusion of active materials, forming a "T-shaped peak" phenomenon at the edge of the pattern. At the same time, the swelling of the photoresist film caused by the absorption of developer by the cross-linked network during development further limits the improvement of the ultimate resolution. These problems are the main technical bottlenecks restricting its application in more advanced processes.

[0007] Third, the methods for controlling the performance of photoresists are limited. Existing epoxy negative photoresists are mostly polymer systems with a wide molecular weight distribution, making it difficult to achieve precise molecular-level structural control. Furthermore, in short-wavelength exposure scenarios such as extreme ultraviolet lithography, the absorption efficiency of traditional epoxy resins is insufficient, making it difficult to meet the demands of higher resolution patterning.

[0008] Therefore, improving the sensitivity of epoxy negative photoresists, suppressing the swelling effect during development, enhancing the absorption efficiency under short-wavelength exposure, and achieving performance regulation at the molecular structure level are technical problems that urgently need to be solved in this field. Summary of the Invention

[0009] (a) Technical problems to be solved

[0010] To address at least one of the aforementioned technical problems, this disclosure provides a polyphenol compound and its preparation method, an epoxy resin, and a photoresist composition thereof. By designing a polyphenol compound with a molecular glass framework structure, consisting of multiple phenol structural units alternately linked with methylene groups, each phenol structural unit independently possessing 1 to 3 tunable substituents, the molecular weight distribution is unified and the structure is controllable, effectively suppressing the swelling effect during the development process. The polyphenol compound is reacted with an epoxy haloalkane to obtain an epoxy resin, which is further compounded with a photoacid-generating agent and a solvent to form an epoxy negative photoresist composition. This photoresist composition significantly improves sensitivity, resolution, and process adaptability, and can be widely used in semiconductor manufacturing, microelectromechanical system packaging, and advanced photolithography processes.

[0011] (II) Technical Solution

[0012] To address the aforementioned technical problems, embodiments of this disclosure provide a polyphenol compound and its preparation method, as well as an epoxy resin and its photoresist composition.

[0013] According to a first aspect of this disclosure, a polyphenol compound is provided, which is composed of a plurality of phenolic structural units alternately linked with methylene groups, and the polyphenol compound has the structure shown in general formula (I):

[0014] (I)

[0015] Where n is an integer greater than or equal to 0; the number x of substituents R in different phenol structural units may be the same or different, and the value of x is 1, 2 or 3; each substituent R is independently selected from C1 to C2. 10 Alkyl, C1~C 10 One of alkoxy, ester, ether, aryl, polysubstituted aryl, heteroatom-containing alkylaryl, cyano, and halogen.

[0016] In some exemplary embodiments, when n is even, the structure of the polyphenol compound is symmetrical about the center point; when n is odd, the structure of the polyphenol compound is symmetrical about the central phenolic structural unit.

[0017] In some exemplary embodiments, at least one of the substituents R is a halogen.

[0018] In some exemplary embodiments, the structure of the polyphenol compound is selected from any of the following structural formulas:

[0019] ;

[0020] ;

[0021] ;

[0022] ;or

[0023] .

[0024] According to a second aspect of this disclosure, a method for preparing the above-mentioned polyphenol compound is provided, comprising the following steps: Step S1, reacting a first phenolic compound with formaldehyde in the presence of an alkaline catalyst to undergo a hydroxymethylation reaction to generate a benzyl alcohol intermediate, wherein the first phenolic compound has 1 to 3 substituents on its benzene ring, each substituent being independently selected from C1 to C2. 10 Alkyl, C1~C 10 One of the following groups: alkoxy, ester, ether, aryl, polysubstituted aryl, heteroatom-containing alkylaryl, cyano, and halogen; Step S2: The benzyl alcohol intermediate is subjected to a dehydration condensation reaction with a second phenolic compound in the presence of an acid catalyst to generate a condensation product; Step S3: Using the condensation product as the starting material, steps S1 and S2 are repeated. For each complete hydroxymethylation-condensation cycle, the number of phenolic structural units increases by 2 until a polyphenolic compound with the target number of phenolic structural units is obtained; wherein, when the number of phenolic structural units in the polyphenolic compound is even, the first phenolic compound and the second phenolic compound are the same, and the condensation product is a dimer; when the number of phenolic structural units in the polyphenolic compound is odd, the first phenolic compound is a dihydroxymethylphenolic compound, the second phenolic compound is a phenolic compound, and the condensation product is a trimer; the substituents of the phenolic compounds used in different reaction steps may be the same or different.

[0025] According to a third aspect of this disclosure, an epoxy resin is provided, which is prepared by reacting the above-mentioned polyphenol compound with an epoxy haloalkane in the presence of a base catalyst, and the epoxy resin has the structure shown in general formula (II):

[0026] (II)

[0027] Wherein, n is an integer greater than or equal to 0; the number of substituents R in different phenol structural units is the same or different, and the value of x is 1, 2 or 3; each substituent R is independently selected from one of C1~C10 alkyl, C1~C10 alkoxy, ester, ether, aryl, polysubstituted aryl, heteroatom-containing alkylaryl, cyano and halogen.

[0028] In some exemplary embodiments, the structure of the epoxy resin is selected from any of the following structural formulas:

[0029] ;

[0030] ;

[0031] ;

[0032] ;or

[0033] .

[0034] According to a fourth aspect of this disclosure, a photoresist composition is provided, comprising: the aforementioned epoxy resin; a photoacid generator; and a solvent; wherein, based on the total mass of the photoresist composition, the epoxy resin has a mass percentage of 0.5% to 30%; and the photoacid generator has a mass percentage of 0.05% to 30%.

[0035] In some exemplary embodiments, the photoacid-generating agent is selected from one or more of diaryliodomonium salts, triarylthiomonium salts, nonionic sulfonates, diazonaphthoquinones, and carbonates; the solvent is selected from one or more of n-butyl acetate, ethyl acetate, propylene glycol methyl ether acetate, propylene glycol methyl ether, ethyl lactate, and cyclohexanone.

[0036] In some exemplary embodiments, the photoresist composition further includes additives; the additives are 0.001% to 15% by mass based on the total mass of the photoresist composition; the additives are selected from one or more of quenchers, solvent promoters, dissolution inhibitors, leveling agents and stabilizers.

[0037] Furthermore, this disclosure also provides applications of the above-mentioned photoresist composition, which is suitable for various exposure sources and photolithography processes, specifically including: projection lithography, interference lithography, or SP lithography using i-line (wavelength 365nm) as the exposure source; 248nm or 193nm projection lithography, interference lithography, and spatial image lithography using deep ultraviolet light as the exposure source; extreme ultraviolet lithography using extreme ultraviolet light (wavelength 13.5nm) as the exposure source; and electron beam direct-write lithography using an electron beam as the exposure source. This photoresist composition can form high-resolution, high-fidelity lithographic patterns in the above-mentioned photolithography scenarios and can be widely used in semiconductor integrated circuit manufacturing, microelectromechanical system packaging, microfluidic chip fabrication, and advanced packaging processes.

[0038] (III) Beneficial Effects

[0039] As can be seen from the above technical solutions, the polyphenol compound and its preparation method, epoxy resin and its photoresist composition provided in this disclosure have at least the following beneficial effects:

[0040] (1) Effectively suppresses development swelling and improves resolution. This disclosure designs a polyphenol compound with a molecular glass framework structure, in which multiple phenol structural units are alternately linked with methylene groups to form a linear framework. The molecular weight distribution is uniform and the structure is controllable, avoiding the problem of uneven moisture absorption and swelling of the crosslinked network during development caused by the wide molecular weight distribution of traditional polymer photoresists. This significantly improves the limit resolution of the pattern, and a 30nm resolution pattern can be achieved under electron beam exposure.

[0041] (2) Significantly improves sensitivity and short-wavelength absorption efficiency. This disclosure introduces halogen substituents into the phenol structural unit, and utilizes the high absorption cross-section of halogen atoms under extreme ultraviolet lithography conditions to improve the energy absorption efficiency of the photoresist at short wavelengths; at the same time, halogen atoms can decompose to generate free radicals during exposure, further increasing the epoxy crosslinking density, thereby ensuring sufficient crosslinking while reducing the exposure dose, effectively solving the problems of low sensitivity and low processing efficiency of traditional epoxy negative adhesives.

[0042] (3) Achieving tunable performance at the molecular structure level. This disclosure allows for precise control of the molecular polarity, solubility, and photochemical reactivity of polyphenol compounds by changing the type (e.g., methyl, tert-butyl, phenyl, halogen, etc.) and number (1 to 3 substituents per benzene ring) of the substituents on the phenol structural units; by controlling the number of methylene repeats (i.e., the number of phenol structural units), the molecular weight and crosslinking density can be adjusted, thereby obtaining a series of tunable epoxy resins to meet the needs of different photolithography process windows.

[0043] (4) Excellent high-resolution patterning capability. The epoxy negative photoresist composition prepared in this disclosure exhibits excellent resolution performance under various exposure sources: high-density patterns with a period of 30 nm can be obtained under electron beam exposure, dense patterns with a period of 35 nm can be obtained under extreme ultraviolet light, and patterns with a period of 200 nm can be obtained under 266 nm interference lithography. It can also be used in near-contact lithography (such as SP lithography). The linewidth to slit width ratio of the pattern obtained by this photoresist composition can reach 1:1, with clear pattern edges, steep sidewalls, and no "T-top" or pattern bridging defects.

[0044] (5) Strong process adaptability and broad application prospects. The photoresist composition disclosed herein is suitable for various exposure sources such as i-line, deep ultraviolet light, extreme ultraviolet light, and electron beam, and can be widely used in semiconductor integrated circuit manufacturing, microelectromechanical system packaging, microfluidic chip fabrication, and advanced packaging processes, providing a reliable solution for high-resolution patterning. At the same time, this photoresist composition can achieve high-performance patterning using either a non-chemical amplification mechanism or a combination of chemical amplification mechanisms, exhibiting a wide process window and good industrial applicability. Attached Figure Description

[0045] The foregoing contents, as well as other objects, features, and advantages of this disclosure, will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0046] Figure 1 A flowchart illustrating a method for preparing a polyphenol compound according to embodiments of the present disclosure is shown schematically.

[0047] Figure 2 The illustration schematically shows a lithographic pattern with a period of 200 nm obtained by interference lithography on epoxy resin h1, which was prepared according to Example 1 of this disclosure, as the main component.

[0048] Figure 3 The illustration schematically shows a 60nm periodic photolithography pattern obtained by electron beam exposure using epoxy resin h1 as the main component prepared according to Example 1 of this disclosure;

[0049] Figure 4 The illustration schematically shows a 60nm periodic lithography pattern obtained by electron beam exposure using epoxy resin h2 as the main component prepared according to Example 2 of this disclosure;

[0050] Figure 5 The illustration schematically shows a 60nm periodic lithography pattern obtained by electron beam exposure using epoxy resin h3 as the main component prepared according to Example 3 of this disclosure;

[0051] Figure 6The illustration schematically shows the 35nm and 45nm periodic lithographic patterns obtained by extreme ultraviolet lithography using epoxy resin h1 as the main component prepared according to Example 1 of this disclosure;

[0052] Figure 7 The illustration schematically shows the 35nm and 45nm periodic lithographic patterns obtained by extreme ultraviolet lithography using epoxy resin h2 as the main component prepared according to Example 2 of this disclosure.

[0053] Figure 8 The illustration schematically shows the 35nm and 45nm periodic lithographic patterns obtained by extreme ultraviolet lithography using epoxy resin h4 as the main component prepared according to Example 4 of this disclosure. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0055] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0056] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0057] According to a first aspect of the present disclosure, a polyphenol compound is provided, characterized in that the polyphenol compound is composed of a plurality of phenol structural units alternately linked with methylene groups, and the polyphenol compound has a structure shown in general formula (I):

[0058] (I)

[0059] Where n is an integer greater than or equal to 0; the number x of substituents R in different phenol structural units may be the same or different, and the value of x is 1, 2 or 3; each substituent R is independently selected from C1 to C2. 10 Alkyl, C1~C 10 One of alkoxy, ester, ether, aryl, polysubstituted aryl, heteroatom-containing alkylaryl, cyano, and halogen.

[0060] According to embodiments of this disclosure, the polyphenol compound employs a linear framework of alternating phenol structural units and methylene groups to form a molecular glass structure with a uniform molecular weight distribution. Unlike traditional polymer photoresists (with a wide molecular weight distribution and entangled molecular chains), this polyphenol compound has a well-defined molecular structure and uniform molecular size, enabling it to form a denser and more uniform molecular stack during film formation. This effectively suppresses the penetration of the developer and the swelling of the film during development. Furthermore, by adjusting the type of substituents (x = 1 to 3) and the chemical structure of the substituent R on each phenol structural unit, the polarity, solubility, light absorption characteristics, and reactivity of the polyphenol compound can be precisely controlled.

[0061] In the embodiments of this disclosure, when n is even, the structure of the polyphenol compound is symmetrical about the central point; when n is odd, the structure of the polyphenol compound is symmetrical about the central phenol structural unit. This symmetry originates from the alternating connection of phenol units and methylene groups during synthesis and the precise control of the hydroxymethylation-condensation reaction. The symmetrical structure facilitates the uniform spreading and orderly arrangement of molecules on the substrate surface, reducing pattern distortion caused by uneven molecular orientation. By controlling the parity of n, the molecular length and symmetry of the polyphenol compound can be precisely controlled, thereby regulating the film-forming properties, dissolution rate, and crosslinking density of the photoresist. The symmetrical structure helps to form photolithographic patterns with steep sidewalls and smooth edges, improving pattern fidelity and uniformity.

[0062] In the embodiments of this disclosure, at least one of the substituents R is a halogen. Halogen atoms (such as chlorine and bromine) have large atomic numbers and high electron densities, exhibiting large absorption cross-sections under extreme ultraviolet light (wavelength 13.5 nm) or electron beam exposure, effectively absorbing incident energy and improving the photon capture efficiency of the photoresist. Simultaneously, halogen atoms can undergo photolysis during exposure, generating halogen free radicals and carbon free radicals. These free radicals can further initiate cationic ring-opening polymerization or free radical crosslinking reactions of epoxy groups, increasing the crosslinking density, thereby ensuring sufficient crosslinking while reducing the exposure dose.

[0063] By introducing halogen substituents into the phenol structural units, the absorption efficiency and sensitivity of the photoresist under extreme ultraviolet (EUV) and electron beam exposure were significantly improved, reducing the required exposure dose and increasing processing efficiency. Simultaneously, the free radicals generated by halogen cleavage promoted epoxy crosslinking, increasing the density of the crosslinked network and further suppressing the swelling effect during development, thereby improving the limiting resolution and sidewall steepness of the pattern. Experiments showed that polyphenol compounds containing halogen substituents could obtain 35 nm periodic patterns under EUV and 30 nm resolution patterns under electron beam exposure.

[0064] Figure 1A flowchart illustrating a method for preparing a polyphenol compound according to an embodiment of the present disclosure is shown.

[0065] like Figure 1 As shown, the method for preparing polyphenol compounds according to embodiments of this disclosure includes steps S1 to S3.

[0066] Step S1 involves reacting the first phenolic compound with formaldehyde in the presence of an alkaline catalyst via hydroxymethylation to generate a benzyl alcohol intermediate. The first phenolic compound has 1 to 3 substituents on its benzene ring, each substituent independently selected from C1 to C2. 10 Alkyl, C1~C 10 Phenol is composed of one of the following groups: alkoxy, ester, ether, aryl, polysubstituted aryl, heteroatom-containing alkylaryl, cyano, and halogen. Under alkaline conditions (such as sodium hydroxide), phenol loses its hydroxyl proton to generate a phenol oxonium, which significantly activates the ortho and para positions of the benzene ring, enhancing its nucleophilicity. The phenol oxonium attacks the carbonyl carbon of formaldehyde, undergoing nucleophilic addition to generate the o-hydroxymethylphenol intermediate. The key to this reaction lies in utilizing the ortho-para directing effect of the phenol hydroxyl group to introduce a hydroxymethyl group at a specified position, providing an active site for the subsequent condensation reaction.

[0067] Step S2 involves a dehydration condensation reaction between the benzyl alcohol intermediate and a second phenolic compound in the presence of an acid catalyst to generate a condensation product. Under acidic conditions (such as p-toluenesulfonic acid), the hydroxymethyl group (-CH2OH) in the benzyl alcohol intermediate is protonated and loses its water molecule, forming a highly reactive benzyl carbocation. This carbocation acts as an electrophile, attacking the ortho or para position of the hydroxyl group in the second phenolic compound, resulting in an electrophilic aromatic substitution reaction. The two phenolic structural units are linked together via a methylene group (-CH2-) to generate the condensation product.

[0068] When the number of phenolic structural units in a polyphenol compound is even, the first and second phenolic compounds are identical, and the condensation product is a dimer (two phenolic structural units linked by methylene groups). When the number of phenolic structural units in a polyphenol compound is odd, the first phenolic compound is a dihydroxymethylphenolic compound, the second phenolic compound is a phenolic compound, and the condensation product is a trimer (three phenolic structural units linked by methylene groups). By selecting different starting materials, the synthetic starting points for even and odd numbers of phenolic structural units can be achieved, respectively.

[0069] Step S3 involves repeating steps S1 and S2 using the condensation product as the starting material. Each completed hydroxymethylation-condensation cycle increases the number of phenolic structural units by two, until a polyphenol compound with the target number of phenolic structural units is obtained. By controlling the number of cycles, a polyphenol compound with the target number of phenolic structural units can be precisely obtained.

[0070] The use of the same or different substituents in the phenolic compounds in different reaction steps allows for the same or different combinations of substituents on each phenolic structural unit of the final polyphenol compound, thereby enabling flexible control over molecular polarity, solubility, reactivity, and photolithographic properties. The key to this cyclic growth mechanism is that each reaction occurs at the active site at the molecule's end, avoiding intramolecular condensation or cross-linking side reactions and ensuring the linearity of the product and the uniformity of its molecular weight distribution.

[0071] This disclosure achieves the precise synthesis of polyphenolic compounds with a single molecular weight distribution, controllable structure, and tunable substituents through the aforementioned three-step cyclic reaction using readily available phenolic compounds as raw materials. The method features mild reaction conditions, simple operation, and allows for flexible customization of polyphenolic compounds with different degrees of polymerization and functional properties by selecting phenolic compounds with different substituents and adjusting the number of cycles. This provides a well-defined molecular basis for the subsequent preparation of high-performance epoxy resins and photoresist compositions.

[0072] For example, when the number of phenol structural units is even, the synthesis method is as follows:

[0073]

[0074] When the number of phenol structural units is odd, the synthesis method is as follows:

[0075]

[0076] In the embodiments of this disclosure, x, y, z, and m are integers from 1 to 3; R1, R2, R3, and R4 can be alkyl groups with 1 to 10 carbon atoms, such as methyl or ethyl groups, or C1 to C4 groups. 10 Alkoxy, ester, ether, aryl, polysubstituted aryl, heteroatom-containing alkylaryl, cyano, halogen, and other substituent groups are acceptable. Preferred substituents include methyl, halogen, phenyl, and tert-butyl. The substituents on different phenol structural units can be the same or different; that is, the substituents of the phenolic compounds used in each reaction step can be selected as needed.

[0077] The experimental conditions for the synthesis of b from a (hydroxymethylation reaction) are as follows: ① Dissolve 1 part reactant a, 0.8–8 parts formaldehyde solution, 1–5 parts sodium chloride, and 0.5–2 parts sodium hydroxide in 500–5000 parts water and react at room temperature. After the reaction is complete, acidify with sulfuric acid or hydrochloric acid, and detect the reaction endpoint by thin-layer chromatography. The precipitated white solid is adjusted to pH 3–4 with acetic acid, filtered, washed, and then extracted with ethyl acetate to remove water. Combine the organic layers, dry with anhydrous sodium sulfate, evaporate the solvent, slurry with dichloromethane / petroleum ether, filter, and dry to obtain compound b.

[0078] The experimental conditions ② for the formation of compound c from compound b (condensation reaction) are as follows: 2–6 parts of a phenolic compound containing substituent R2 and 1 part of compound b are used as starting materials. 0.1–0.8 parts of p-toluenesulfonic acid are added as a catalyst. The reaction solvent is selected from one or more of toluene, xylene, or ethylbenzene. After the reaction is complete, the mixture is filtered, and the solid is slurried with dichloromethane / petroleum ether to obtain a white solid compound. This solid compound is then further purified by column chromatography to obtain compound c.

[0079] The experimental conditions for the formation of compound i from compound h (substitution condensation reaction) are as follows: 1 part of a dihydroxymethylphenol compound containing substituent R2 and 2–5 parts of a phenol compound containing substituent R1 are used as raw materials. 0.1–2 parts of sulfuric acid are added as a catalyst, and the reaction is carried out using methanol or ethanol as a solvent. After the reaction is complete, the mixture is extracted, and the organic phase is washed successively with deionized water, oxalic acid solution, and deionized water. The organic phase is concentrated, slurried with dichloromethane and petroleum ether, filtered, washed with toluene, and dried to obtain a solid.

[0080] A cyclic growth method for an even number of phenol structural units begins with compound c. First, under experimental condition ①, a hydroxymethylation reaction is performed to generate benzyl alcohol intermediate d. Then, under experimental condition ②, a condensation reaction is carried out with a phenolic compound to obtain compound e. This process continues, starting with e, first under experimental condition ① to generate benzyl alcohol intermediate f, and then under experimental condition ②, a condensation reaction is carried out with a phenolic compound to obtain compound g. By repeating the above hydroxymethylation-condensation cycle, the number of phenol structural units increases by 2 with each cycle, gradually generating polyphenol compounds with 2n phenol structural units.

[0081] Cyclic growth of an odd number of phenol structural units: Starting with compound h, a condensation reaction is first carried out under experimental condition ③ to generate compound i; then, a hydroxymethylation reaction is carried out under experimental condition ① to generate benzyl alcohol intermediate j; then, under experimental condition ②, a condensation reaction with a phenolic compound is carried out to obtain compound k. Similarly, starting from k, a benzyl alcohol intermediate l is generated under experimental condition ①, and then, under experimental condition ②, a condensation reaction with a phenolic compound is carried out to obtain compound m. By repeating the above reaction cycle, the number of phenol structural units increases by 2 with each cycle, gradually generating polyphenol compounds with (2n+1) phenol structural units.

[0082] According to another aspect of the present disclosure, an epoxy resin is provided, which is prepared by reacting the above-mentioned polyphenol compound with an epoxy haloalkane in the presence of a base catalyst, and the epoxy resin has the structure shown in general formula (II):

[0083] (II)

[0084] Wherein, n is an integer greater than or equal to 0; the number of substituents R in different phenol structural units is the same or different, and the value of x is 1, 2 or 3; each substituent R is independently selected from one of C1~C10 alkyl, C1~C10 alkoxy, ester, ether, aryl, polysubstituted aryl, heteroatom-containing alkylaryl, cyano and halogen.

[0085] The epoxy resin provided in this disclosure is prepared by a Williamson etherification reaction of the aforementioned polyphenolic compound with an epoxy haloalkane (such as epichlorohydrin or epibromopropane) in the presence of an alkaline catalyst. The reaction principle is as follows: the phenolic hydroxyl group (-OH) at the end of the polyphenolic compound deprotonates under alkaline catalysis, forming a phenoxy anion. This anion acts as a nucleophile, attacking the carbon atom in the epoxy haloalkane molecule bonded to a halogen, resulting in a nucleophilic substitution reaction. The halide ion departs, forming an epoxypropyl ether group (-O-CH2-CH(O)CH2). This reaction is carried out in a polar solvent such as tetrahydrofuran at a temperature of 50°C to 80°C for 3 to 24 hours, yielding a high yield of epoxy resin product.

[0086] Through the above reaction, the phenolic hydroxyl groups at the ends of the polyphenol compound are converted into glycidyl ether groups, transforming the originally linear polyphenol compound capped with phenolic hydroxyl groups into an epoxy resin with multiple epoxy groups at both ends and inside the molecule (when n>1). This epoxy resin retains the molecular glass framework structural characteristics of the polyphenol compound, namely, the linear structure of alternating phenolic structural units and methylene groups, the uniform molecular weight distribution, the symmetrical structure, and the tunable substituents, while introducing highly reactive epoxy groups, laying the foundation for the subsequent exposure and crosslinking reaction of the photoresist.

[0087] By introducing glycidyl ether groups at both ends of a polyphenol compound, the resin molecule acquires multiple crosslinkable epoxy functional groups. During exposure in the presence of a photoacid generator, an active acid is produced, catalyzing the cationic ring-opening polymerization of the epoxy groups to form a highly crosslinked three-dimensional network structure. This crosslinking mechanism ensures a significant difference in solubility between exposed and unexposed areas in the developer, thereby achieving high-contrast patterning.

[0088] Epoxy resins inherit the molecular glass framework structure of polyphenol compounds, namely a linear, rigid framework formed by alternating phenolic structural units and methylene groups. This structure results in a uniform molecular weight distribution, avoiding the development swelling problems caused by molecular chain entanglement and wide molecular weight distribution in traditional polymer photoresists. This is beneficial for forming high-resolution patterns with steep sidewalls and smooth edges.

[0089] By altering the number of phenolic structural units (n-value) in polyphenol compounds, the molecular weight, crosslinking density, and glass transition temperature of epoxy resins can be controlled, thereby adjusting the sensitivity, resolution, and mechanical properties of photoresists. By changing the type, number, and position (x-value) of substituents R on the phenolic structural units, the polarity, solubility, and light absorption characteristics of the resin can be adjusted. In particular, introducing halogens into the substituents R significantly improves the resin's absorption efficiency under extreme ultraviolet light and promotes free radical crosslinking, thus enhancing the sensitivity of the photoresist.

[0090] For example, taking compound c grafted with epoxy groups as an example, the chemical reaction for generating epoxy resin under experimental condition ④ is as follows:

[0091]

[0092] Experimental condition ④ is as follows: 1 part of compound c, 4-50 parts of base, and 4-50 parts of epichlorohydrin or epibromopropane are dissolved in 500-5000 parts of tetrahydrofuran to form the reaction system. The base is selected from inorganic bases such as cesium carbonate, potassium carbonate, and sodium hydroxide, or from one or more organic bases such as triethylamine and 1,8-diazabicyclo[5.4.0]undec-7-ene. The reaction is carried out at 50℃ to 80℃ for 3 to 24 hours. After the reaction, the solvent is evaporated, and the mixture is extracted with ethyl acetate. The organic layer is dried with anhydrous sodium sulfate, and the solvent is evaporated again. The mixture is then stirred and purified by column chromatography to obtain the epoxy grafted product.

[0093] The grafting of epoxy groups onto other compounds such as e, g, k, and m was carried out under the experimental conditions described above (④).

[0094] Based on the above-mentioned epoxy resin, this disclosure also provides a photoresist composition, comprising: the above-mentioned epoxy resin, a photoacid generator, and a solvent; wherein, based on the total mass of the photoresist composition, the mass percentage of epoxy resin is 0.5% to 30%; the mass percentage of the photoacid generator is 0.05% to 30%. The remainder is solvent, and additives may be added as needed to appropriately reduce the amount of solvent.

[0095] Optionally, the photoacid-generating agent is selected from one or more of diaryliodomonium salts, triarylthiomonium salts, nonionic sulfonates, diazonaphthoquinones, and carbonates; the solvent is selected from one or more of n-butyl acetate, ethyl acetate, propylene glycol methyl ether acetate, propylene glycol methyl ether, ethyl lactate, and cyclohexanone.

[0096] In some exemplary embodiments, the photoresist composition further includes additives; the additives are present in a mass percentage of 0.001% to 15% based on the total mass of the photoresist composition. The additives are selected from one or more of quenchers, solvent promoters, dissolution inhibitors, leveling agents, and stabilizers.

[0097] The photoresist composition according to embodiments of this disclosure can be used for various exposure sources and photolithography processes, specifically including: projection lithography, interference lithography, or SP lithography using an i-line (wavelength 365nm) as the exposure source; 248nm or 193nm projection lithography, interference lithography, and spatial image lithography using deep ultraviolet light as the exposure source; extreme ultraviolet lithography using extreme ultraviolet light (wavelength 13.5nm) as the exposure source; and electron beam direct-write lithography using an electron beam as the exposure source. This photoresist composition can form high-resolution, high-fidelity lithographic patterns in the above-mentioned photolithography scenarios and can be widely used in semiconductor integrated circuit manufacturing, microelectromechanical system packaging, microfluidic chip fabrication, and advanced packaging processes.

[0098] Example 1:

[0099] In this embodiment, a polyphenol compound with four phenol structural units and chlorine-substituents was synthesized and further grafted with epoxy groups to obtain epoxy resin h1.

[0100] The synthesis route is as follows:

[0101]

[0102] The operation steps are as follows:

[0103] (1) Dissolve 2,5-dimethylphenol (10 g, 81.8 mmol), sodium chloride (5.88 g, 100.5 mmol), and sodium hydroxide (2.94 g, 73.6 mmol) in 20 mL of water. Add 37% formaldehyde solution (25.1 mL, 327.4 mmol) at 25 °C and stir for 8 h. Add 50% H2SO4 (2.3 mL water + 1.2 mL H2SO4) and continue the reaction for 4 h. The reaction was stopped by TLC and a white solid precipitated. Adjust the pH of the white solid to 3-4 with acetic acid, filter, wash, and extract the water from the solid with ethyl acetate. Combine the organic layers, dry with anhydrous sodium sulfate, evaporate to dryness, slurry with dichloromethane / petroleum ether, filter, and dry to obtain 15 g of white solid (benzyl alcohol intermediate), with a yield of 65.1%.

[0104] (2) Weigh p-chlorophenol (9.5 g, 74.3 mmol) and 10 mL of hydrochloric acid and dissolve them in toluene (70 mL). Add benzyl alcohol intermediate (5.0 g, 15.8 mmol) at 30 °C. After the reaction is complete, filter the mixture, dissolve the solid in ethyl acetate and mix it with the solution. Separate the solid by column chromatography (petroleum ether: ethyl acetate = 10:1) to give 2.2 g of white solid compound, with a yield of 30.5%.

[0105] (3) Weigh the compound obtained in step (2) (100 mg, 186.0 µmol) and cesium carbonate (727.4 mg, 2.2 mmol), dissolve them in 5 mL of tetrahydrofuran, stir the mixture at 50 °C for 3 h, add epichlorohydrin (305.8 mg, 2.2 mmol), and continue stirring overnight. After the reaction is complete, evaporate the solvent, extract with ethyl acetate, dry the organic layer with anhydrous sodium sulfate, evaporate to dryness, mix the sample, and separate by column chromatography (petroleum ether: ethyl acetate = 5:1) to obtain 65 mg of colorless oil.

[0106] Data representation of h1:

[0107] 1 H NMR (600 MHz, DMSO-d 6 ) δ 7.19 (dd, J = 8.7, 2.7 Hz, 2H), 7.04 (d, J= 8.8 Hz, 2H), 6.67 (s, 2H), 6.44 (d, J = 2.6 Hz, 2H), 4.43 (dd, J = 11.6,2.5 Hz, 2H), 4.05 – 3.99 (m, 4H), 3.98 (dd, J = 11.5, 6.3 Hz, 2H), 3.95 – 3.89 (m, 2H), 3.82 (s, 2H), 3.52 (dd, J = 11.2, 6.6 Hz, 2H), 3.42 – 3.38 (m,2H), 3.25 – 3.19 (m, 2H), 2.88 (t, J = 4.7 Hz, 2H), 2.80 – 2.76 (m, 2H), 2.77– 2.72 (m, 2H), 2.55 (dd, J = 5.2, 2.6 Hz, 2H), 2.19 (s, 6H), 1.93 (s, 6H)ppm. 13 C NMR (151 MHz, DMSO-d 6 ) δ 155.19, 154.38, 135.07, 134.65, 131.70,130.82, 130.71, 127.93, 127.65, 126.98, 124.97, 113.95, 74.40, 69.92, 50.46,50.24, 44.17, 44.09, 36.92, 26.21, 16.60, 15.46. ESI-HRMS m / z: [M + Na]+calcd for C 43 H 46O4Cl2Na: 783.24619; found: 783.2453.

[0108] Analysis based on 1H NMR, 1C NMR, and high-resolution mass spectrometry revealed the product to be compound h1.

[0109] Example 2:

[0110] In this embodiment, another tetrameric epoxy resin h2 was synthesized, with methyl and phenyl substituents and no halogens, to compare the effect of substituents on photoresist performance.

[0111] The synthesis route is as follows:

[0112]

[0113] The operation steps are as follows:

[0114] (1) Dissolve 2,5-dimethylphenol (10 g, 81.8 mmol), sodium chloride (5.88 g, 100.5 mmol), and sodium hydroxide (2.94 g, 73.6 mmol) in 20 mL of water. Add 37% formaldehyde solution (25.1 mL, 327.4 mmol) at 25 °C and stir for 8 h. Add 50% H2SO4 (2.3 mL water + 1.2 mL H2SO4) and continue the reaction for 4 h. The reaction was stopped by TLC and a white solid precipitated. Adjust the pH of the white solid to 3-4 with acetic acid, filter, wash, and extract the water from the solid with ethyl acetate. Combine the organic layers, dry with anhydrous sodium sulfate, evaporate to dryness, slurry with dichloromethane / petroleum ether, filter, and dry to obtain 15 g of white solid (benzyl alcohol intermediate), with a yield of 65.1%.

[0115] (2) Weigh p-phenylphenol (12.6 g, 74.3 mmol) and p-toluenesulfonic acid (816 mg, 4.7 mmol) and dissolve them in toluene (50 mL). Add benzyl alcohol intermediate (5.0 g, 15.8 mmol) at 30 °C. After the reaction is complete, evaporate the toluene to dryness, stir the sample, and separate by column chromatography (petroleum ether: ethyl acetate = 10:1) to obtain 300 mg of white solid compound (polyphenol skeleton).

[0116] (3) Weigh the compound obtained in step (2) (100 mg, 161.1 µmol) and cesium carbonate (629.8 mg, 1.9 mmol), dissolve them in 5 mL of tetrahydrofuran, stir the mixture at 50 °C for 3 h, add epichlorohydrin (264.8 mg, 1.9 mmol), and continue stirring overnight. After the reaction is complete, evaporate the solvent, extract with ethyl acetate, dry the organic layer with anhydrous sodium sulfate, evaporate to dryness, mix the sample, and separate by column chromatography (petroleum ether: ethyl acetate = 5:1) to obtain 70 mg of colorless oil.

[0117] h2 data representation:

[0118] 1 H NMR (600 MHz, DMSO-d 6 ) δ 7.42 (dd, J = 8.5, 2.4 Hz, 2H), 7.32 –7.26 (m, 8H), 7.24 – 7.19 (m, 2H), 7.11 (d, J = 8.5 Hz, 2H), 6.75 (s, 2H), 6.65 (s, 2H), 4.47 (dd, J = 11.5, 2.5 Hz, 2H), 4.14 – 3.98 (m, 6H), 3.89 (dd,J = 11.1, 2.6 Hz, 2H), 3.82 (s, 2H), 3.52 (dd, J = 11.1, 6.5 Hz, 2H), 3.43–3.41 (m, 2H), 3.28 – 3.17 (m, 2H), 2.94 – 2.86 (m, 2H), 2.83 – 2.79 (m, 2H), 2.77 – 2.70 (m, 2H), 2.53 (dd, J = 5.1, 2.5 Hz, 2H), 2.03 (s, 6H), 1.95 (s,6H) ppm. 13 C NMR (151 MHz, DMSO-d 6) δ 156.09, 154.47, 140.56, 135.05, 134.69,133.13, 131.28, 130.49, 129.66, 129.27, 127.73, 127.10, 126.45, 126.38,125.72, 112.63, 74.37, 69.69, 50.48, 50.39, 44.22, 44.09, 36.94, 26.43,16.43, 15.56 ppm. ESI-HRMS m / z: [M + Na]+ calcd for C 55 H 56 O8Na: 867.38674; found: 867.3867.

[0119] Analysis based on 1H NMR, 1C NMR, and high-resolution mass spectrometry revealed that the actual product was compound h2.

[0120] Example 3:

[0121] In this embodiment, a tetrameric epoxy resin h3 was synthesized, with methyl and tert-butyl substituents.

[0122] The synthesis route is as follows:

[0123]

[0124] The operation steps are as follows:

[0125] (1) Dissolve 2,5-dimethylphenol (10 g, 81.8 mmol), sodium chloride (5.88 g, 100.5 mmol), and sodium hydroxide (2.94 g, 73.6 mmol) in 20 mL of water. Add 37% formaldehyde solution (25.1 mL, 327.4 mmol) at 25 °C and stir for 8 h. Add 50% H2SO4 (2.3 mL water + 1.2 mL H2SO4) and continue the reaction for 4 h. The reaction was stopped by TLC and a white solid precipitated. Adjust the pH of the white solid to 3-4 with acetic acid, filter, wash, and extract the water from the solid with ethyl acetate. Combine the organic layers, dry with anhydrous sodium sulfate, evaporate to dryness, slurry with dichloromethane / petroleum ether, filter, and dry to obtain 15 g of white solid (benzyl alcohol intermediate), with a yield of 65.1%.

[0126] (2) Weigh p-tert-butylphenol (6.7 g, 44.6 mmol) and p-toluenesulfonic acid (326 mg, 1.9 mmol) and dissolve them in toluene (50 mL). Add benzyl alcohol intermediate (3.0 g, 9.5 mmol) at 30 °C. After the reaction is complete, evaporate the toluene to dryness, stir the sample, and separate by column chromatography (petroleum ether: ethyl acetate = 10:1) to give 1.3 g of white solid compound, yield 34.6%.

[0127] (3) Weigh the compound obtained in step (3) (150 mg, 258.3 µmol) and cesium carbonate (1.0 g, 3.1 mmol) and dissolve them in 5 mL of tetrahydrofuran. After stirring the mixture at 50 °C for 3 h, add epichlorohydrin (424.5 mg, 3.1 mmol) and continue stirring overnight. After the reaction is complete, evaporate the solvent, extract with ethyl acetate, dry the organic layer with anhydrous sodium sulfate, evaporate to dryness, mix the sample, and separate by column chromatography (petroleum ether: ethyl acetate = 5:1) to obtain 100 mg of colorless oil.

[0128] h3 data representation:

[0129] 1 H NMR (600 MHz, DMSO-d 6 ) δ7.08 (dd, J = 8.5, 2.5 Hz, 2H), 6.88 (d, J= 8.6 Hz, 2H), 6.75 (s, 2H), 6.51 (d, J = 2.5 Hz, 2H), 4.36 (dd, J = 11.5,2.6 Hz, 2H), 4.02 – 3.91 (m, 4H), 3.93 (dd, J = 11.5, 6.1 Hz, 2H), 3.82 –3.75 (m, 4H), 3.49 – 3.46 (m, 2H), 3.37 (q, J = 3.9 Hz, 2H), 3.17 – 3.14 (m,2H), 2.86 (dd, J = 5.2, 4.2 Hz, 2H), 2.79 – 2.75 (m, 2H), 2.73 – 2.68 (m,2H), 2.47 – 2.45 (m, 2H), 2.18 (s, 6H), 1.90 (s, 6H), 0.99 (s, 18H) ppm. 13 CNMR (151 MHz, DMSO-d 6) δ 154.50, 154.16, 142.89, 135.15, 134.62, 131.39,130.44, 128.21, 127.61, 125.22, 123.36, 111.58, 74.38, 69.55, 50.44, 50.35,44.20, 44.13, 36.71, 33.96, 31.53, 26.58, 16.76, 15.42. ESI-HRMS m / z: [M +Na]+ calcd for C 51 H 64 O8Na: 827.44934; found: 827.4499.

[0130] Analysis based on 1H NMR, 1C NMR, and high-resolution mass spectrometry revealed that the actual product was compound h3.

[0131] Example 4:

[0132] In this embodiment, a pentamer epoxy resin h4 (an odd number of phenol units) was synthesized, with methyl and chlorine substituents.

[0133] The synthesis route is as follows:

[0134]

[0135] The operation steps are as follows:

[0136] (1) Weigh 2,5-dimethylphenol (357.2 mmol, 43.58 g, 4.0 eq.) and place it in methanol (60 mL). Add sulfuric acid (485 μL) and 2,6-bis(hydroxymethyl)-4-cresol (89.3 mmol, 15 g, 1.0 eq.) at 30 °C. After the reaction is complete, dissolve the 2,6-dimethylphenol in toluene (40 mL) and ethyl acetate (80 mL), wash twice with deionized water (80 mL), wash twice with oxalic acid, wash twice with deionized water (80 mL), concentrate the organic phase, slurry with dichloromethane and petroleum ether, filter, wash with toluene, and dry to obtain 8.4 g of white powder compound 4,4'-((2-hydroxy-5-methyl-1,3-phenylene)bismethylene)bis(2,5-dimethylphenol) (yield 25%).

[0137] (2) Weigh the above compound (22.3 mmol, 8.4 g, 1.0 eq.) and sodium hydroxide (53.52 mmol, 2.14 g, 2.4 eq.) and dissolve them in 110 mL of tetrahydrofuran / water (volume ratio 1:10). Add 37% formaldehyde aqueous solution (10.8 mL, 133.8 mmol, 6.0 eq.) dropwise while stirring at 40 °C. After reacting overnight, cool to room temperature, adjust pH to 5-6 with acetic acid, filter, and wash with water to obtain 8.0 g of white solid compound 4,4'-((2-hydroxy-5-methyl-1,3-phenylene)bis(methylene))bis(2-(hydroxymethyl)-3,6-dimethylphenol) (yield 82%).

[0138] (3) The above compound was dissolved in 50 mL of toluene, and p-toluenesulfonic acid (5.5 mmol, 0.95 g, 0.3 eq.) and p-chlorophenol (86.2 mmol, 11.08 g, 4.7 eq.) were added. The mixture was reacted overnight at 30 °C, and 30 mL of saturated sodium chloride was added. The mixture was separated, and the organic layer was evaporated to dryness. The solid was dissolved in a mixed solvent of toluene and ethyl acetate at 60 °C, and after stirring and washing with deionized water, the mixture was separated, the organic phase was concentrated, filtered, and slurried with dichloromethane and petroleum ether. The slurry was dried to obtain 6.0 g of compound 4,4'-((2-hydroxy-5-methyl-1,3-phenylene)bis(methylene))bis(2-(5-chloro-2-hydroxybenzyl)-3,6-dimethylphenol) (yield 50%).

[0139] (4) The above compound was dissolved in 40 mL of tetrahydrofuran, and Cs2CO3 (137 mmol, 44.7 g, 15.0 eq.) was added. After reacting at 50 °C for 1 h, epichlorohydrin (137 mmol, 18.8 g, 15.0 eq.) was added dropwise, and stirring was continued overnight. After the reaction was completed, the tetrahydrofuran was evaporated to dryness, 50 mL of water was added, and the mixture was extracted three times with ethyl acetate. The organic layer was dried over anhydrous sodium sulfate, evaporated to dryness, and separated by column chromatography (petroleum ether: ethyl acetate = 5:1) to obtain 2.64 g of colorless foamy compound (yield 31%).

[0140] h4 data representation:

[0141] 1H NMR (600 MHz, DMSO-d6) δ 7.17 (dd, J = 8.7, 2.7 Hz, 2H), 7.02 (d, J= 8.8 Hz, 2H), 6.91 (s, 2H), 6.43 (s, 2H), 6.38 (dd, J = 2.7, 1.0 Hz, 2H), 4.41 (ddd, J = 11.5, 2.6, 1.2 Hz, 2H), 4.10 (dd, J = 11.1, 2.6 Hz, 1H), 3.99– 3.90 (m, 11H), 3.63 (dd, J = 11.2, 6.5 Hz, 1H), 3.52 (ddd, J = 11.2, 6.5,0.9 Hz, 2H), 3.38 (ddd, J = 6.6, 3.3, 2.1 Hz, 2H), 3.31 (ddd, J = 6.7, 4.2,2.2 Hz, 2H), 3.22 (tt, J = 6.7, 2.8 Hz, 2H), 2.86 (dd, J = 5.1, 4.2 Hz, 2H), 2.80 – 2.71 (m, 5H), 2.61 (dd, J = 5.1, 2.7 Hz, 1H), 2.54 (dt, J = 5.3, 2.7Hz, 2H), 2.21 (s, 6H), 2.04 (s, 3H), 1.85 (s, 6H)ppm. 13 C NMR (151 MHz, DMSO-d6) δ 154.74, 154.07, 152.22, 134.75, 134.34, 133.12, 132.80, 131.44, 131.18,130.47, 127.86, 127.47, 127.11, 126.51, 124.45, 113.48, 74.06, 73.95, 69.45,50.19, 50.01, 49.78, 43.74, 43.71, 43.65, 32.88, 25.74, 20.76, 16.06, 15.10ppm.

[0142] Analysis based on 1H NMR, 1C NMR, and high-resolution mass spectrometry revealed that the actual product was compound h4.

[0143] Example 5:

[0144] In this embodiment, a hexameric epoxy resin h5 (an odd number of phenol units) was synthesized, with methyl and chlorine substituents.

[0145] The synthesis route is as follows:

[0146]

[0147] The operation steps are as follows:

[0148] (1) Weigh 10 g (82.0 mmol, 1.0 eq.) of 2,5-dimethylphenol and dissolve it in 20 mL of water containing sodium chloride (6 g) and sodium hydroxide (3 g, 75 mmol, 0.9 eq.). Add 25 mL (308 mmol, 3.7 eq.) of 37% formaldehyde at room temperature. After stirring for 5 h, add 4.6 g of 50% sulfuric acid dropwise and heat to 50 °C and stir for 8 h. After the reaction is complete, neutralize with acetic acid, filter, wash with water, dry, and precipitate by column chromatography to obtain 8 g of white compound 4,4'-methylenebis(2-(hydroxymethyl)-3,6-dimethylphenol) (yield 62%).

[0149] (2) Dissolve p-methylphenol (4.32 g, 40 mmol, 4.0 eq.) and p-toluenesulfonic acid (0.52 g, 3 mmol, 0.3 eq.) in toluene (30 mL), and add the above compound (3.16 g, 10 mmol, 1.0 eq.) at 30 °C. After the reaction is complete, dissolve in toluene and ethyl acetate, wash with deionized water at 60 °C, concentrate the organic phase, filter, wash with toluene, and dry to obtain a white solid compound which is directly added to the next step.

[0150] (3) The compound obtained in step (2) above was dissolved in 33 mL of tetrahydrofuran / water solution (volume ratio 1:10), and sodium hydroxide (24.0 mmol, 0.96 g, 2.4 eq.) was added. 37% formaldehyde aqueous solution (4.8 mL, 60 mmol, 6.0 eq.) was added dropwise while stirring at 40 °C. After reacting overnight, the mixture was cooled to room temperature, and the pH was adjusted to 5-6 with acetic acid. The mixture was filtered, washed with water to obtain the crude product, and column chromatography was used to obtain 3.0 g of pure compound 4,4'-methylenebis(2-(2-hydroxy-3-(hydroxymethyl)-5-methylbenzyl)-3,6-dimethylphenol) (two-step yield 54%).

[0151] (4) Dissolve p-chlorophenol (3.25 g, 4.7 eq.) and p-toluenesulfonic acid (0.28 g, 0.3 eq.) in toluene (10 mL), and add the compound obtained in step (3) above (3.0 g, 5.4 mmol, 1.0 eq.) at 30 °C. After the reaction is complete, dissolve in ethyl acetate, wash with deionized water, stir at 60 °C until clear, separate the liquid, concentrate the organic phase, add petroleum ether to slurry, dry to obtain crude product, and column chromatography to obtain 1.17 g of white solid compound 4,4'-methylenebis(2-(3-(5-chloro-2-hydroxybenzyl)-2-hydroxy-5-methylbenzyl)-3,6-dimethylphenol) (yield 28%).

[0152] (5) The compound obtained in step (4) above (1.17 g, 1.5 mmol, 1.0 eq.) was dissolved in 40 mL of tetrahydrofuran, and Cs2CO3 (27 mmol, 8.8 g, 18.0 eq.) was added. After reacting at 50 °C for 1 h, epichlorohydrin (27 mmol, 3.7 g, 18.0 eq.) was added dropwise, and stirring was continued overnight. After the reaction was completed, the tetrahydrofuran was removed by rotary evaporation, 50 mL of water was added, and the mixture was extracted three times with ethyl acetate. The organic layer was dried over anhydrous sodium sulfate, evaporated to dryness, and separated by column chromatography (petroleum ether: ethyl acetate = 5:1) to obtain 0.8 g of a colorless foamy compound (yield 48%).

[0153] h5 data representation:

[0154] 1H NMR (600 MHz, DMSO-d6) δ 7.22 (dd, J = 8.7, 2.7 Hz, 2H), 7.05 –6.98 (m, 4H), 6.70 (t, J = 2.2 Hz, 2H), 6.64 (s, 2H), 6.21 (d, J = 2.2 Hz,2H), 4.34 – 4.28 (m, 2H), 4.25 – 4.18 (m, 2H), 4.12 – 4.03 (m, 4H), 3.93 (s,4H), 3.91 – 3.86 (m, 4H), 3.78 (s, 2H), 3.74 (ddd, J = 11.2, 6.7, 2.9 Hz,2H), 3.51 (ddd, J = 11.1, 6.5, 1.4 Hz, 2H), 3.43 – 3.38 (m, 2H), 3.27 (ddt, J= 6.3, 4.7, 1.8 Hz, 2H), 3.20 (tdd, J = 6.6, 3.0, 1.7 Hz, 2H), 2.84 (ddd, J =5.2, 4.2, 0.9 Hz, 2H), 2.80 (ddd, J = 4.9, 4.2, 0.6 Hz, 2H), 2.72 – 2.68 (m,4H), 2.67 – 2.65 (m, 2H), 2.53 (dt, J = 5.3, 2.9 Hz, 2H), 2.16 (s, 6H), 2.00(s, 6H), 1.91 (s, 6H) ppm. 13 C NMR (151 MHz, DMSO-d6) δ 154.89, 153.87,152.44, 134.53, 134.25, 133.43, 132.75, 132.18, 131.40, 131.37, 131.29,130.02, 129.65, 129.63, 128.62, 127.16, 126.94, 126.92, 124.35, 113.71,73.95, 73.87, 73.85, 69.34, 50.28, 50.01, 49.67, 43.74, 43.72, 43.67, 43.64, 29.22, 25.92, 20.69, 16.17, 15.10 ppm.

[0155] Analysis based on 1H NMR, 1C NMR, and high-resolution mass spectrometry revealed that the actual product obtained was compound h5.

[0156] Example 6: Preparation of photoresist composition and its performance in 266nm interference lithography

[0157] Using epoxy resin h1 prepared in Example 1 as the main component, a photoacid generator (diphenyl-(4-phenylthio)phenylsulfonium hexafluoroantimonate) and additives were added, and propylene glycol methyl ether acetate (PGMEA) was used as the solvent to prepare a photoresist composition. Based on the total mass of the photoresist composition, the mass percentages of h1, photoacid generator, additives, and PGMEA were 7.346%, 0.735%, 0.092%, and 91.827%, respectively. This photoresist formulation was used to prepare a photoresist film on a silicon wafer and exposed using a 266nm interference lithography apparatus. Process conditions: pre-baking 80°C for 60 s; post-baking 80°C for 60 s; developer: methyl isobutyl ketone (MIBK), development 30 s; fixer: isopropanol (IPA), fixing 15 s. The exposure dose was 20 mJ / cm². 2 The resulting photolithographic pattern is as follows: Figure 2 As shown, the period is 200 nm.

[0158] The chlorine atoms in the h1 structure have a certain absorption under deep ultraviolet light, and the rigid framework of the methylene bridge makes the photoresist swell less during development. Combined with optimized formulation and process conditions, interference lithography patterns with a period of 200 nm were successfully achieved.

[0159] Example 7: Electron beam lithography performance (h1)

[0160] Epoxy resin h1 was used as the main component, along with a photoacid generator (triphenylthiohexafluoroantimonate) and additives, and PGMEA was used as the solvent to prepare a photoresist composition. Based on the total mass of the photoresist composition, the mass percentages of h1, photoacid generator, additives, and PGMEA were 2.583%, 0.517%, 0.032%, and 96.868%, respectively. A photoresist film was prepared on a silicon wafer using this formulation, and a 60 nm periodic interference pattern was fabricated by electron beam exposure. Process conditions: pre-baking at 80℃ for 60 s; post-baking at 80℃ for 60 s; developer: hexyl acetate, development for 30 s; fixer: IPA, fixing for 30 s. The exposure dose was 54 μC / cm². 2 The resulting photolithographic pattern is as follows: Figure 3 As shown, the period is 60 nm.

[0161] The molecular glass framework structure of h1 ensures a uniform molecular weight distribution, avoiding the swelling and rough edges that occur with polymer photoresists due to their wider molecular weight distribution. The introduction of chlorine atoms allows for the generation of free radicals during electron beam exposure, promoting epoxy cross-linking, improving sensitivity, and thus achieving high-resolution patterns of 60 nm.

[0162] Example 8: Electron beam lithography performance (h2)

[0163] Using epoxy resin h2 as the main component, electron beam exposure was performed according to the same formulation and process conditions as in Example 7, with an exposure dose of 20 μC / cm. 2 The resulting photolithographic pattern is as follows: Figure 4 As shown, the period is 60 nm.

[0164] The phenyl substituent in h2 provides higher rigidity, resulting in higher sensitivity than h1 (exposure dose from 54 μC / cm). 2 Reduced to 20 μC / cm 2 .

[0165] Example 9: Electron beam lithography performance (h3)

[0166] Using epoxy resin H3 as the main component, electron beam exposure was performed according to the same formulation and process conditions as in Example 7, with an exposure dose of 96 μC / cm. 2 The resulting photolithographic pattern is as follows: Figure 5 As shown, the period is 60 nm.

[0167] The tert-butyl substituent in h3 is relatively large, which may affect intermolecular stacking and crosslinking density, requiring a higher exposure dose to achieve sufficient crosslinking. However, a 60 nm resolution pattern was still obtained, demonstrating that the structural design disclosed in this paper has a wide process window.

[0168] Example 10: Extreme ultraviolet lithography performance (h1)

[0169] Using epoxy resin h1 as the main component, a photoresist film was prepared according to the same formulation as in Example 7, and exposed using extreme ultraviolet light. Process conditions: pre-baking 80°C for 60 s; post-baking 80°C for 60 s; developer: hexyl acetate, development for 30 s; fixer: IPA, fixing for 30 s. Exposure dose: 9.3 mJ / cm². 2 The resulting photolithographic pattern is as follows: Figure 6 The figures shown are for 35 nm and 45 nm periods, respectively.

[0170] Principle and Effect: Extreme ultraviolet light has a very short wavelength (13.5 nm), and traditional photoresists have low absorption efficiency. The chlorine atoms introduced into the h1 molecule have a large absorption cross-section, which significantly improves the absorption efficiency of extreme ultraviolet light. At the same time, the free radicals generated by halogen decomposition promote cross-linking, allowing the photoresist to react fully even at a lower exposure dose, thereby obtaining a high-resolution pattern of 35 nm.

[0171] Example 11: Extreme ultraviolet lithography performance (h2)

[0172] Using epoxy resin h2 as the main component, extreme ultraviolet light exposure was performed under the same conditions as in Example 10, with an exposure dose of 9.3 mJ / cm². 2 The resulting photolithographic pattern is as follows: Figure 7 The figures shown are periodic patterns at 35 nm and 45 nm, respectively.

[0173] h2 has no halogen substitution, but it can still obtain a 35 nm resolution pattern, which may be due to the contribution of the phenyl substituent to the extreme ultraviolet light absorption. This shows that the polyphenol compounds disclosed in this paper can achieve extreme ultraviolet lithography performance through various substituent designs.

[0174] Example 12: Extreme ultraviolet lithography performance (h4)

[0175] Using epoxy resin H4 as the main component, extreme ultraviolet light exposure was performed under the same conditions as in Example 10, with an exposure dose of 9.3 mJ / cm². 2 The resulting photolithographic pattern is as follows: Figure 8 The figures shown are periodic patterns at 35 nm and 45 nm, respectively.

[0176] h4 is a pentamer (an odd number of phenol units), and its structure is symmetrical about the central phenol structural unit. Its chlorine-containing substituents also improve the extreme ultraviolet light absorption efficiency, and a high-resolution pattern comparable to that of the tetramer is obtained. This proves that the molecular glass framework structure disclosed in this paper can achieve excellent photolithography performance regardless of whether the number of phenol units is odd or even.

[0177] In summary, this disclosure successfully prepared a series of epoxy resins and formulated photoresist compositions by designing polyphenol compounds with molecular glass framework structures. These photoresist compositions exhibit high-resolution patterning capabilities under various exposure sources, including electron beam, extreme ultraviolet (EUV), 266nm interference lithography, and i-line lithography, achieving resolutions of up to 30nm (electron beam) or 35nm (UV), significantly superior to traditional epoxy negative photoresists. Furthermore, by changing the type and number of substituents on the phenol structural units, the sensitivity, resolution, and process window of the photoresist can be flexibly controlled, providing a reliable material solution for advanced photolithography processes.

[0178] Those skilled in the art will understand that the features described in the various embodiments of this disclosure can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in this disclosure. In particular, the features described in the various embodiments of this disclosure can be combined and / or combined in various ways without departing from the spirit and teachings of this disclosure. All such combinations and / or combinations fall within the scope of this disclosure.

Claims

1. A polyphenol compound, characterized in that, The polyphenol compound is composed of multiple phenolic structural units alternately linked with methylene groups, and the polyphenol compound has the structure shown in general formula (I):       （I） Where n is an integer greater than or equal to 0; The number of substituents R in different phenol structural units may be the same or different, and the value of x is 1, 2 or 3; Each substituent R is independently selected from C1 to C2. 10 Alkyl, C1~C 10 One of alkoxy, ester, ether, aryl, polysubstituted aryl, heteroatom-containing alkylaryl, cyano, and halogen.

2. The polyphenol compound according to claim 1, characterized in that, When n is an even number, the structure of the polyphenol compound is symmetrical about the center point; When n is an odd number, the structure of the polyphenol compound is symmetrical about the central phenol structural unit.

3. The polyphenol compound according to claim 1, characterized in that, At least one of the substituents R is a halogen.

4. The polyphenol compound according to claim 1, characterized in that, The structure of the polyphenol compound is selected from any one of the following structural formulas: ； ； ； ;or 。 5. A method for preparing the polyphenol compound according to any one of claims 1 to 4, characterized in that, Includes the following steps: Step S1 involves reacting a first phenolic compound with formaldehyde in the presence of an alkaline catalyst via hydroxymethylation to generate a benzyl alcohol intermediate. The first phenolic compound has 1 to 3 substituents on its benzene ring, each substituent being independently selected from C1 to C2. 10 Alkyl, C1~C 10 One of the following: alkoxy, ester, ether, aryl, polysubstituted aryl, heteroatom-containing alkylaryl, cyano, and halogen; Step S2: The benzyl alcohol intermediate and the second phenolic compound are subjected to a dehydration condensation reaction in the presence of an acid catalyst to generate a condensation product. Step S3: Using the condensation product as the starting material, repeat steps S1 and S2. Each time a hydroxymethylation-condensation cycle is completed, the number of phenol structural units increases by 2 until a polyphenol compound with the target number of phenol structural units is obtained. Wherein, when the number of phenol structural units in the polyphenol compound is even, the first phenol compound is the same as the second phenol compound, and the condensation product is a dimer; When the number of phenolic structural units in the polyphenolic compound is odd, the first phenolic compound is a dihydroxymethylphenolic compound, the second phenolic compound is a phenolic compound, and the condensation product is a trimer; The phenolic compounds used in different reaction steps may have the same or different substituents.

6. An epoxy resin, characterized in that, The epoxy resin is prepared by reacting the polyphenol compound of any one of claims 1 to 4 with an epoxy haloalkane in the presence of a base catalyst, and the epoxy resin has the structure shown in general formula (II):    （Ⅱ）    Where n is an integer greater than or equal to 0; The number of substituents R in different phenol structural units may be the same or different, and the value of x is 1, 2 or 3; Each substituent R is independently selected from one of C1-C10 alkyl, C1-C10 alkoxy, ester, ether, aryl, polysubstituted aryl, heteroatom-containing alkylaryl, cyano, and halogen.

7. The epoxy resin according to claim 6, characterized in that, The structure of the epoxy resin is selected from any one of the following structural formulas: ； ； ； ;or 。 8. A photoresist composition, characterized in that, include: The epoxy resin as described in claim 6 or 7; Photoacid-producing agents; And solvents; Wherein, based on the total mass of the photoresist composition, the epoxy resin has a mass percentage of 0.5% to 30%; and the photoacid generator has a mass percentage of 0.05% to 30%.

9. The photoresist composition according to claim 8, characterized in that, The photo-induced acid-producing agent is selected from one or more of diaryliodomonium salts, triarylthiomonium salts, nonionic sulfonates, diazonaphthoquinones, and carbonates; The solvent is selected from one or more of n-butyl acetate, ethyl acetate, propylene glycol methyl ether acetate, propylene glycol methyl ether, ethyl lactate, and cyclohexanone.

10. The photoresist composition according to claim 8 or 9, characterized in that, The photoresist composition also includes additives; Based on the total mass of the photoresist composition, the additives account for 0.001% to 15% by mass. The additive is selected from one or more of quenchers, solvent promoters, dissolution inhibitors, leveling agents, and stabilizers.

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