Bottom anti-reflection coating resin as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of photoetching, and particularly relates to bottom anti-reflection coating resin as well as a preparation method and application thereof. The preparation method is characterized in that through innovative monomer combination design and polymerization process regulation and control, firstly, terephthalic acid, 5-hydroxyisophthalic acid, alkyl dihydric alcohol and pentaerythritol are used as raw materials to synthesize a polyester prepolymer with a specific and appropriate molecular weight, and then the polyester prepolymer and an amino resin cross-linking agent are subjected to an ether exchange reaction; therefore, the bottom anti-reflection coating resin with a'rigid-flexible 'three-dimensional network structure is constructed and has high heat resistance and strong chemical resistance, and when the resin is used as a bottom anti-reflection coating composition component to prepare a photoetching pattern, not only can high optical matching performance be guaranteed, but also the anti-reflection effect is improved. Meanwhile, the thermal stability and the chemical stability of the anti-reflection coating are also remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of photolithography technology, specifically relating to a bottom anti-reflective coating resin, its preparation method, and its application. Background Technology

[0002] As semiconductor integrated circuits (ICs) evolve towards ultra-large scale and high integration, chip manufacturing process nodes have progressed from the traditional 10nm to advanced processes such as 5nm, 3nm, and even smaller. Photolithography, as a core step in semiconductor manufacturing, directly determines the critical dimension (CD) and yield of devices. Bottom anti-reflective coating (BARC), a key functional material between the photoresist and the substrate (such as silicon wafers, silicon oxide, or low-k dielectric layers), significantly improves the clarity and dimensional uniformity of the photoresist pattern by absorbing / scattering incident light and adjusting reflectivity during photolithography exposure. It is an indispensable material for ensuring the precision of advanced photolithography processes. Currently, semiconductor manufacturing places increasingly stringent demands on photolithography processes. On the one hand, the wavelength of light sources continues to shorten (e.g., evolving from 193nm ArF excimer lasers to 13.5nm EUV extreme ultraviolet lasers), requiring higher precision in the optical matching (refractive index n, extinction coefficient k) of BARC (Bold Arsenic Resin). On the other hand, the strong chemical environment of etching processes (such as plasma dry etching), the stress accumulation of multilayer stacked structures, and the thermal shock of high-temperature baking (such as soft baking, hard baking, and post-curing) all require BARC to possess excellent thermal stability, chemical resistance, and structural reliability. However, the performance bottleneck of existing BARC resins under extreme process conditions has become one of the key challenges restricting the advancement of advanced processes.

[0003] Traditional BARC resins are typically based on unsaturated monomers such as acrylates, epoxy acrylates, or cyclosulfide acrylates, forming a cross-linked network through free radical polymerization or cationic polymerization. Although the refractive index and extinction coefficient of such materials can be optimized by adjusting the monomer composition, their three-dimensional network structure still has significant defects in stability and resistance to extreme environments, specifically: (1) Under high temperature (>200℃) or strong polar solvents (such as TMAH in developer), the cross-linked network of existing BARC resins is prone to collapse or swelling, which in turn causes film shrinkage, refractive index drift (Δn>0.02) or extinction coefficient mismatch (Δk>0.01), ultimately affecting the linewidth accuracy of the photolithography pattern (CD uniformity decreases by 5%~10%); (2) For advanced processes ( For example, below 7nm), the post-bake temperature often needs to be increased to 220~250℃ to enhance the interfacial bonding between the photoresist and BARC. However, the thermal decomposition temperature (onset temperature) of existing resins is generally lower than 250℃. At high temperatures, thermal oxidation degradation or side chain shedding is likely to occur, generating small molecule volatiles that contaminate the photolithography equipment, or forming defects (such as pinholes) in the film layer, resulting in a decrease in etching selectivity (etching rate deviation >15%): (3) In the plasma etching process, BARC needs to withstand fluorine (CF4, CHF3) and chlorine (Cl2, BC) content. l3 The film is bombarded by corrosive gases such as hydroxyl and ester groups, and comes into contact with strong acid or alkaline etching byproducts. The main chain or side chain of the existing resin contains a large number of unsaturated double bonds or polar groups (such as hydroxyl and ester groups), which are easily attacked or protonated by free radicals, resulting in film swelling, interface debonding, and even residues on the substrate surface after etching, causing short circuits or leakage risks in the device. Summary of the Invention

[0004] One of the objectives of this invention is to address the significant deficiencies in the three-dimensional structural stability, heat resistance, and chemical stability of existing BARC resins, which have become a major obstacle to improving the precision and yield of photolithography processes in advanced semiconductor manufacturing processes (especially nodes below 5nm). This invention provides a method for preparing a bottom anti-reflective coating resin with a stable three-dimensional network structure, thereby obtaining a resin with high heat resistance and strong chemical resistance.

[0005] Specifically, the method for preparing the bottom anti-reflective coating resin includes the following steps: S1. Terephthalic acid, 5-hydroxyisophthalic acid, alkyl diol, pentaerythritol, and organic solvent I are mixed and subjected to polycondensation reaction in an inert gas atmosphere and in the presence of catalyst I until the weight average molecular weight of the resulting polyester prepolymer is 3000~5000 g / mol and the reaction is stopped. S2. The obtained polyester prepolymer and amino resin crosslinking agent undergo ether exchange reaction in organic solvent II and in the presence of catalyst II. The resulting reaction product is the bottom anti-reflective coating resin.

[0006] In a preferred embodiment, the weight-average molecular weight of the bottom antireflective coating resin is 6000~10000 g / mol, and the PDI is 1.55~1.96.

[0007] In a preferred embodiment, in step S1, the molar ratio of terephthalic acid, 5-hydroxyisophthalic acid, alkyl diol and pentaerythritol is (2.0~3.0):(0.5~1.0):(2.0~3.0):1.

[0008] In a preferred embodiment, in step S1, the amount of organic solvent I is 40-50 wt% of the total mass of the reaction raw materials, wherein the total mass of the reaction raw materials is the total mass of terephthalic acid, 5-hydroxyisophthalic acid, alkyl diol, and pentaerythritol.

[0009] In a preferred embodiment, in step S1, the amount of catalyst I is 0.4 to 0.6 wt% of the total mass of the reaction raw materials, wherein the total mass of the reaction raw materials is the total mass of terephthalic acid, 5-hydroxyisophthalic acid, alkyl diol, and pentaerythritol.

[0010] In a preferred embodiment, step S1 includes a polycondensation reaction and a post-polycondensation reaction performed sequentially.

[0011] In a preferred embodiment, in step S1, the conditions for the esterification reaction include: a temperature of 130~140℃ and a time of 3~5h.

[0012] In a preferred embodiment, in step S1, the conditions for the post-condensation reaction include: a temperature of 142~150℃ and a time of 1~2h.

[0013] In a preferred embodiment, step S1, the method for stopping the reaction includes: controlling the reaction temperature to 70~80°C and adding a diluent.

[0014] In a preferred embodiment, in step S1, the diluent is selected from at least one of methyl 2-hydroxyisobutyrate, ethyl lactate, and ethyl acetoacetate.

[0015] In a preferred embodiment, in step S2, the amount of the amino resin crosslinking agent is 15-25 wt% of the polyester prepolymer.

[0016] In a preferred embodiment, in step S2, the conditions for the ether exchange reaction include: a temperature of 100~110℃ and a time of 0.5~1.5h.

[0017] In a preferred embodiment, the alkyl diol has the general chemical formula HO-R-OH, wherein R is a C1-C5 straight-chain alkylene or branched alkylene.

[0018] In a preferred embodiment, organic solvent I and organic solvent II are each independently selected from at least one of anisole, phenethyl ether, diphenyl ether, diethylene glycol butyl ether, and propylene glycol phenyl ether.

[0019] In a preferred embodiment, both catalyst I and catalyst II are acidic catalysts; each of catalyst I and catalyst II is independently selected from at least one of p-toluenesulfonic acid, methanesulfonic acid, sulfuric acid, and phosphoric acid.

[0020] In a preferred embodiment, the amino resin crosslinking agent is selected from at least one of hexamethylol melamine hexamethyl ether, hexaethoxymethyl melamine, hexapropoxymethyl melamine, tetramethoxymethyl glycourea, and benzomelamine.

[0021] The second objective of this invention is to provide a bottom anti-reflective coating resin prepared by the above method.

[0022] A third objective of this invention is to provide the application of the aforementioned bottom antireflective coating resin in a bottom antireflective coating composition. The bottom antireflective coating composition contains the aforementioned bottom antireflective coating resin, an acid-generating agent, a crosslinking agent, and organic solvent III.

[0023] A fourth objective of this invention is to provide the application of the aforementioned bottom anti-reflective coating resin in the preparation of photolithographic patterns. The application includes forming an anti-reflective coating of the aforementioned bottom anti-reflective coating resin between a substrate and a photoresist.

[0024] Beneficial effects: The key to this invention lies in the innovative monomer combination design and polymerization process control. First, a polyester prepolymer with a specific and suitable molecular weight is synthesized using terephthalic acid, 5-hydroxyisophthalic acid, alkyl diol, and pentaerythritol as raw materials. Then, the polyester prepolymer undergoes an ether exchange reaction with an amino resin crosslinking agent, thereby constructing a bottom antireflective coating resin (BARC resin) with a "rigid and flexible" three-dimensional network structure. It has high heat resistance and strong chemical resistance. When this resin is used as a component of the bottom antireflective coating composition in the preparation of photolithographic patterns, it can not only ensure high optical matching, but also significantly improve the thermal and chemical stability of the antireflective coating. Attached Figure Description

[0025] Figure 1 This is a thermogravimetric analysis diagram of the bottom antireflective coating resin obtained in Example 1 of the present invention.

[0026] Figure 2This is a thermogravimetric analysis diagram of the bottom antireflective coating resin obtained in Comparative Example 2 of the present invention. Detailed Implementation

[0027] 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. Furthermore, unless otherwise specified, all embodiments and optional embodiments of the present invention can 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.

[0028] The method for preparing the bottom anti-reflective coating resin provided by the present invention includes the following steps: S1. Terephthalic acid, 5-hydroxyisophthalic acid, alkyl diol, pentaerythritol, and organic solvent I are mixed and subjected to polycondensation reaction in an inert gas atmosphere and in the presence of catalyst I until the weight average molecular weight of the resulting polyester prepolymer is 3000~5000 g / mol and the reaction is stopped. S2. The obtained polyester prepolymer and amino resin crosslinking agent undergo ether exchange reaction in organic solvent II and in the presence of catalyst II. The resulting reaction product is the bottom anti-reflective coating resin.

[0029] The weight-average molecular weight (Mw) of the polyester prepolymer can be 3000 g / mol, 3200 g / mol, 3500 g / mol, 3800 g / mol, 4000 g / mol, 4200 g / mol, 4500 g / mol, 4800 g / mol, 5000 g / mol, or any value between them. Controlling the weight-average molecular weight of the polyester prepolymer within the above range is beneficial in two ways: firstly, it ensures that the final bottom antireflective coating resin has good coating performance and film-forming effect; secondly, it facilitates the formation of a stable and compact three-dimensional network structure in the resin, thereby improving the heat resistance and chemical resistance of the bottom antireflective coating resin.

[0030] In this invention, the weight-average molecular weight of the bottom antireflective coating resin is preferably 6000~10000 g / mol, such as 6000 g / mol, 6500 g / mol, 7000 g / mol, 7200 g / mol, 7500 g / mol, 7700 g / mol, 8000 g / mol, 8500 g / mol, 9000 g / mol, 9500 g / mol, 10000 g / mol, or any value between them. The PDI of the bottom antireflective coating resin is preferably 1.55~1.96, such as 1.55, 1.60, 1.70, 1.80, 1.90, 1.96, or any value between them.

[0031] In this invention, in step S1, the preferred molar ratio of terephthalic acid, 5-hydroxyisophthalic acid, alkyl diol, and pentaerythritol is (2.0~3.0):(0.5~1.0):(2.0~3.0):1. Taking 1 mol of pentaerythritol as the unit of measurement, the preferred amount of terephthalic acid is 2.0~3.0 mol, such as 2.0 mol, 2.2 mol, 2.5 mol, 2.8 mol, 3.0 mol, or any value between them; the preferred amount of 5-hydroxyisophthalic acid is 0.5~1.0 mol, such as 0.5 mol, 0.6 mol, 0.7 mol, 0.8 mol, 0.9 mol, 1.0 mol, or any value between them; the preferred amount of alkyl diol is 2.0~3.0 mol, such as 2.0 mol, 2.2 mol, 2.5 mol, 2.8 mol, 3.0 mol, or any value between them. When the amounts of terephthalic acid, 5-hydroxyisophthalic acid, alkyl diols, and pentaerythritol are controlled within the above-mentioned preferred range, it is more conducive to the formation of abundant branching points in the polymer, laying a solid foundation for the final formation of a stable and compact three-dimensional network and providing suitable flexibility. This is because if the proportion of pentaerythritol is too high, the crosslinking density will be too large, and the prepolymer synthesis stage will be prone to gelation, and the final resin will be too hard and brittle (it is prone to cracking under thermal or mechanical stress, affecting process compatibility). If the proportion of pentaerythritol is too low, the degree of branching will be insufficient, and an effective network cannot be formed, and the final properties (hardness, heat resistance) will decrease. When the ratio of alkyl diols to benzene rings is moderate, their flexible aliphatic chains can offset the brittleness caused by rigid benzene rings.

[0032] In this invention, in step S1, the amount of organic solvent I is preferably 40-50 wt% of the total mass of the reactants, such as 40 wt%, 42 wt%, 45 wt%, 48 wt%, 50 wt%, or any value between them. The total mass of the reactants is the total mass of terephthalic acid, 5-hydroxyisophthalic acid, alkyl diol, and pentaerythritol.

[0033] In this invention, in step S1, the amount of catalyst I is preferably 0.4~0.6 wt% of the total mass of the reactants, such as 0.4 wt%, 0.45 wt%, 0.5 wt%, 0.55 wt%, 0.6 wt%, or any value between them. The total mass of the reactants is the total mass of terephthalic acid, 5-hydroxyisophthalic acid, alkyl diol, and pentaerythritol.

[0034] In this invention, step S1 preferably includes a sequential esterification reaction and a post-condensation reaction. This has the advantage of lower gelation probability and more thorough transesterification. This is because early temperature control allows for esterification between the reactant monomers, inhibiting the premature formation of locally high crosslinking density regions by the multifunctional monomer (pentaerythritol). This significantly reduces the risk of gelation failure in the middle of the reaction. Later temperature increases promote post-condensation of the low molecular weight prepolymer, better adjusting the polymer structure and making the molecular weight distribution more uniform. The preferred conditions for the esterification reaction include: a temperature of 130-140°C, such as 130°C, 132°C, 134°C, 137°C, 140°C, or any value between them; and a time of 3-5 hours, such as 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, or any value between them. The preferred conditions for the post-condensation reaction include: a temperature of 142~150℃, such as 142℃, 144℃, 146℃, 148℃, 150℃ or any value between them; and a time of 1~2h, such as 1h, 1.2h, 1.5h, 1.8h, 2h or any value between them.

[0035] In this invention, step S1, the method for stopping the reaction preferably includes: controlling the reaction temperature to 70-80°C, such as 70°C, 72°C, 75°C, 78°C, 80°C, or any value between them, and adding a diluent. In a specific embodiment, the method for stopping the reaction can be as follows: controlling the reaction temperature to 70-80°C, adding the diluent dropwise to the reaction system, and stirring evenly at 70-80°C. The diluent not only acts as a chemical end-capping agent to stop chain growth, but also reduces the viscosity of the system, thereby facilitating the subsequent ether exchange reaction. Specific examples of the diluent include, but are not limited to, at least one of methyl 2-hydroxyisobutyrate, ethyl lactate, and ethyl acetoacetate.

[0036] In this invention, in step S2, the amount of the amino resin crosslinking agent is preferably 15 to 25 wt% of the polyester prepolymer mass, such as 15 wt%, 18 wt%, 20 wt%, 22 wt%, 25 wt%, or any value between them.

[0037] In this invention, the conditions for the ether exchange reaction in step S2 preferably include: a temperature of 100~110℃, such as 100℃, 102℃, 105℃, 108℃, 110℃ or any value therebetween; and a time of 0.5~1.5h, such as 0.5h, 0.8h, 1.0h, 1.2h, 1.5h or any value therebetween.

[0038] In this invention, the preferred chemical formula of the alkyl diol is HO-R-OH, wherein R is a C1-C5 straight-chain alkylene or branched alkylene. Specific examples of the straight-chain alkylene and branched alkylene include, but are not limited to, any one of: -CH2-, -CH2CH2-, -CH(CH3)-, -CH2CH2CH2-, -CH(CH3)CH2-, -CH(CH2CH3)-, -C(CH3)2-, -(CH2)4-, -CH(CH3)CH2CH2-, -CH(CH2CH3)CH2-, -CH2CH(CH3)CH2-, -C(CH3)2CH2-, -(CH2)5-, -CH(CH3)CH2CH2CH2-, -CH2CH(CH3)CH2CH2-, -C(CH3)2CH2CH2-, and -CH2C(CH3)2CH2-. Specific examples of the alkyl diols include, but are not limited to, at least one of: methyl glycol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,4-butanediol, and neopentyl glycol.

[0039] In this invention, organic solvent I and organic solvent II are each preferably selected independently from at least one of anisole, phenethyl ether, diphenyl ether, diethylene glycol butyl ether, and propylene glycol phenyl ether.

[0040] In this invention, both catalyst I and catalyst II are preferably acidic catalysts. Each of catalyst I and catalyst II is independently preferred from at least one of p-toluenesulfonic acid, methanesulfonic acid, sulfuric acid, and phosphoric acid.

[0041] In this invention, the amino resin crosslinking agent is a type of methyl etherified crosslinking agent, and specific examples include, but are not limited to, at least one of: hexamethylol melamine hexamethyl ether, hexaethoxymethyl melamine, hexapropoxymethyl melamine, tetramethoxymethyl glycourea, and benzomelamine.

[0042] The present invention provides a bottom anti-reflective coating resin prepared by the above method.

[0043] This invention provides a bottom antireflective coating composition comprising a bottom antireflective coating resin prepared by the above method, an acid-generating agent, a crosslinking agent, and organic solvent III. The specific types of the acid-generating agent, crosslinking agent, and organic solvent III can be conventionally selected in the art.

[0044] This invention also provides the application of the bottom anti-reflective coating resin prepared by the above method in the preparation of photolithographic patterns. Specifically, the application can be as follows: forming an anti-reflective coating containing the bottom anti-reflective coating resin between a substrate and a photoresist. The method for forming the anti-reflective coating can be as follows: coating a bottom anti-reflective coating composition containing the bottom anti-reflective coating resin onto a substrate, followed by curing to form the anti-reflective coating. The curing method can be thermosetting.

[0045] Furthermore, the terms "Ⅰ", "Ⅱ", and "Ⅲ" are used only for descriptive purposes and do not have any special meaning.

[0046] The present invention will be described in detail below through specific embodiments. These embodiments are intended to explain the invention and should not be construed as limiting it. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0047] Example 1 This embodiment illustrates the preparation of a bottom anti-reflective coating resin (BARC resin), and the specific process is as follows: Weigh 49.83 g (0.30 mol) terephthalic acid, 18.21 g (0.10 mol) 5-hydroxyisophthalic acid, 33.66 g (0.32 mol) neopentyl glycol, and 16.33 g (0.12 mol) pentaerythritol and add them to a four-necked reaction flask (equipped with a mechanical stirrer, thermometer, water separator, reflux condenser, and nitrogen inlet tube). Then add 58.00 g of anisole solvent (50 wt% of the total solid raw material mass), and purge the air in the system by introducing nitrogen gas at a flow rate of 50 mL / min.

[0048] Start stirring at 250 rpm and slowly heat to 100°C to fully dissolve the solid raw materials. Then add 0.59 g of p-toluenesulfonic acid catalyst (0.5 wt% of the total solid raw material mass) and continue heating to 135°C to begin the esterification reaction for 3-5 hours. During this period, closely observe the amount of water produced and separate the generated water using a water separator until the amount of water produced reaches 85% of the theoretical value. Then raise the reaction temperature to 145°C and continue the reaction for 1-2 hours. During this period, take samples every 0.5 hours to test the Mw value of the reaction product. When the Mw value of the polyester prepolymer is 3800 g / mol, lower the reaction temperature to 75°C and slowly add 20 g of methyl 2-hydroxyisobutyrate dropwise through a constant pressure dropping funnel for dilution. The dropping time is controlled at 30 min. After the dropping is completed, keep the mixture at 75°C and stir for 30 min to ensure the system is homogeneous.

[0049] The system temperature was lowered to 100℃, and hexamethyl melamine hexamethyl ether (HMMM) (20wt% of the solid mass of the polyester prepolymer) was slowly added over a period of 20 min. Then, the ether exchange reaction was carried out at 100℃ for 30 min.

[0050] Cool the reaction system to 50°C. Dissolve triethylamine (1.1 stoichiometric equivalents required to neutralize the p-toluenesulfonic acid catalyst) in 10g of methyl 2-hydroxyisobutyrate to prepare a neutralizing agent. Slowly add the neutralizing agent dropwise to the reaction system over a period of 15-20 minutes. After the addition is complete, continue stirring at 50°C for 30 minutes to ensure complete neutralization.

[0051] Isopropanol (6 times the total solids content) and n-heptane (4 times the total solids content) were added to a washing vessel. The neutralized reaction solution was then added dropwise to the washing vessel to induce precipitation over approximately 30 minutes. After standing for 2 hours, the supernatant was collected, and the resulting precipitate was the BARC resin. The Mw of this BARC resin was determined to be 7700 g / mol, and the PDI was 1.77.

[0052] Example 2 This embodiment illustrates the preparation of a bottom anti-reflective coating resin (BARC resin), and the specific process is as follows: Weigh 58.14 g (0.35 mol) terephthalic acid, 10.92 g (0.06 mol) 5-hydroxyisophthalic acid, 37.49 g (0.36 mol) neopentyl glycol, and 16.33 g (0.12 mol) pentaerythritol and add them to a four-necked reaction flask (equipped with a mechanical stirrer, thermometer, water separator, reflux condenser, and nitrogen inlet tube). Then add 58.00 g of anisole solvent (50 wt% of the total solid raw material mass), and purge the air in the system by introducing nitrogen gas at a flow rate of 50 mL / min.

[0053] Start stirring at 250 rpm and slowly heat to 100°C to fully dissolve the solid raw materials. Then add 0.53 g of p-toluenesulfonic acid catalyst (0.5 wt% of the total solid raw material mass) and continue heating to 130°C to begin the esterification reaction for 3-5 hours. During this period, closely observe the amount of water produced and separate the generated water using a water separator until the amount of water produced reaches 85% of the theoretical value. Then raise the reaction temperature to 142°C and continue the reaction for 1-2 hours. During this period, take samples every 0.5 hours to test the Mw value of the reaction product. When the Mw value of the polyester prepolymer is 3000 g / mol, lower the reaction temperature to 75°C and slowly add 20 g of methyl 2-hydroxyisobutyrate dropwise through a constant pressure dropping funnel for dilution. The dropping time is controlled at 30 min. After the dropping is completed, keep the mixture at 75°C and stir for 30 min to ensure the system is homogeneous.

[0054] The system temperature was lowered to 100℃, and hexamethyl melamine hexamethyl ether (HMMM) (20wt% of the solid mass of the polyester prepolymer) was slowly added over a period of 20 min. Then, the ether exchange reaction was carried out at 100℃ for 30 min.

[0055] Cool the reaction system to 50°C. Dissolve triethylamine (1.1 stoichiometric equivalents required to neutralize the p-toluenesulfonic acid catalyst) in 10g of methyl 2-hydroxyisobutyrate to prepare a neutralizing agent. Slowly add the neutralizing agent dropwise to the reaction system over a period of 15-20 minutes. After the addition is complete, continue stirring at 50°C for 30 minutes to ensure complete neutralization.

[0056] Isopropanol (6 times the total solids content) and n-heptane (4 times the total solids content) were added to a washing vessel. The neutralized reaction solution was then added dropwise to the washing vessel to induce precipitation over approximately 30 minutes. After standing for 2 hours, the supernatant was collected, and the resulting precipitate was the BARC resin. The Mw of this BARC resin was determined to be 6400 g / mol, and the PDI was 1.68.

[0057] Example 3 This embodiment illustrates the preparation of a bottom anti-reflective coating resin (BARC resin), and the specific process is as follows: Weigh 41.53 g (0.25 mol) terephthalic acid, 21.85 g (0.12 mol) 5-hydroxyisophthalic acid, 25.00 g (0.24 mol) neopentyl glycol, and 16.33 g (0.12 mol) pentaerythritol and add them to a four-necked reaction flask (equipped with a mechanical stirrer, thermometer, water separator, reflux condenser, and nitrogen inlet tube). Then add 58.00 g of anisole solvent (50 wt% of the total solid raw material mass), and purge the air in the system with nitrogen gas at a flow rate of 50 mL / min.

[0058] Start stirring at 250 rpm and slowly heat to 100°C to fully dissolve the solid raw materials. Then add 0.52 g of p-toluenesulfonic acid catalyst (0.5 wt% of the total solid raw material mass) and continue heating to 140°C to begin the esterification reaction for 3-5 hours. During this stage, closely observe the amount of water produced and separate the generated water using a water separator until the amount of water produced reaches 85% of the theoretical value. Then raise the reaction temperature to 150°C and continue the reaction. During this period, take samples every 0.5 hours to test the Mw value of the reaction product. When the Mw value of the polyester prepolymer is 4800 g / mol, lower the reaction temperature to 75°C and slowly add 20 g of methyl 2-hydroxyisobutyrate dropwise through a constant pressure dropping funnel for dilution. The dropping time is controlled at 30 min. After the dropping is completed, keep the mixture at 75°C and stir for 30 min to ensure the system is homogeneous.

[0059] The system temperature was lowered to 100℃, and hexamethyl melamine hexamethyl ether (HMMM) (20wt% of the solid mass of the polyester prepolymer) was slowly added over a period of 20 min. Then, the ether exchange reaction was carried out at 100℃ for 30 min.

[0060] Cool the reaction system to 50°C. Dissolve triethylamine (1.1 stoichiometric equivalents required to neutralize the p-toluenesulfonic acid catalyst) in 10g of methyl 2-hydroxyisobutyrate to prepare a neutralizing agent. Slowly add the neutralizing agent dropwise to the reaction system over a period of 15-20 minutes. After the addition is complete, continue stirring at 50°C for 30 minutes to ensure complete neutralization.

[0061] Isopropanol (6 times the total solids content) and n-heptane (4 times the total solids content) were added to a washing vessel. The neutralized reaction solution was then added dropwise to the vessel to induce precipitation over approximately 30 minutes. After standing for 2 hours, the supernatant was collected, and the resulting precipitate was the BARC resin. The Mw of this BARC resin was determined to be 7400 g / mol, and the PDI was 1.75.

[0062] Example 4 This embodiment illustrates the preparation of a bottom anti-reflective coating resin (BARC resin), and the specific process is as follows: A reference BARC resin was prepared according to the method of Example 1, except that the same amount of tetramethoxymethyl glycourea was used instead of hexamethyl melamine hexamethyl ether, and all other conditions were the same as in the example. The BARC resin was thus prepared. The Mw of this BARC resin was measured to be 6800 g / mol, and the PDI was 1.65.

[0063] Example 5 This embodiment illustrates the preparation of a bottom anti-reflective coating resin (BARC resin), and the specific process is as follows: A reference BARC resin was prepared according to the method of Example 1, except that the amount of pentaerythritol used was 0.05 mol, while all other conditions were the same as in the example. The BARC resin was thus prepared. The Mw of this BARC resin was measured to be 6300 g / mol, and the PDI was 1.63.

[0064] Example 6 This embodiment illustrates the preparation of a bottom anti-reflective coating resin (BARC resin), and the specific process is as follows: A reference BARC resin was prepared according to the method of Example 1, except that the amount of pentaerythritol used was 0.20 mol, while all other conditions were the same as in the example. The BARC resin was thus prepared. The Mw of this BARC resin was measured to be 7600 g / mol, and the PDI was 1.75.

[0065] Comparative Example 1 Ordinary BARC resin: 0.3 mol of methyl 9-anthracene methacrylate, 0.3 mol of 3-hydroxypropyl acrylate, 0.2 mol of glycidyl methacrylate, and 0.2 mol of methyl methacrylate were added to a round-bottom flask. Under stirring, this mixture was added to 300 g of THF. Then, in the presence of 0.1 g of AIBN (azobisisobutyronitrile), the reaction mixture was polymerized at 60 °C for 20 h under a nitrogen atmosphere. After polymerization, the solution was precipitated in n-hexane, and the precipitate was filtered to obtain the polymer, which is the BARC resin. The Mw of this BARC resin was measured to be 6400 g / mol, and the PDI was 1.74.

[0066] Comparative Example 2 Traditional heat-resistant polyester-type BARC resin: 8.3 g (0.043 mol) of dimethyl terephthalate, 10.0 g (0.038 mol) of tris(2-hydroxyethyl) isocyanurate, and 0.05 g of tetrabutyl titanate were added sequentially to a three-necked flask. Nitrogen gas was introduced to purge air from the system. The temperature was raised to 160 °C, and the dimethyl terephthalate and tris(2-hydroxyethyl) isocyanurate underwent transesterification for 3 hours. The generated methanol byproduct was collected in a water separator after condensation. The temperature was gradually raised to 180 °C and maintained for 2 hours until methanol distilled off. Maintaining a nitrogen atmosphere, the temperature was further raised to 200 °C, and a vacuum was applied. The temperature was then raised to 210 °C, and the reaction was carried out under vacuum for 4 hours. Heating was stopped, the vacuum was closed, and the mixture was cooled to room temperature. The solution was precipitated in n-heptane, and the precipitate was filtered to obtain the polyester-type BARC resin. The Mw of this BARC resin was measured to be 7900 g / mol, and the PDI was 1.73.

[0067] Comparative Example 3 This comparative example illustrates the preparation of a reference BARC resin, and the specific process is as follows: A reference BARC resin was prepared according to the method of Example 1, except that the same molar amount of 1,2,3,4-butanetetrol was used instead of pentaerythritol, while all other conditions were the same as in Example 1. The reference BARC resin was found to have a molecular weight (Mw) of 3200 g / mol and a phosphorus content (PDI) of 1.34.

[0068] Test case The resins obtained from the above examples and comparative examples were subjected to performance tests according to the following methods, and the results are shown in Table 1.

[0069] (1) Heat resistance test: A certain mass of resin powder sample was weighed and heated from 40°C to 600°C at a rate of 10°C / min using a thermogravimetric analyzer (TGA) under a nitrogen atmosphere. The mass change of the sample during the entire test process was recorded, and the pyrolysis temperature (Onset temperature, the temperature at which the sample weight begins to show a "significant and continuous decrease" on the TGA curve) was obtained by automatically fitting the tangent method using software. The TGA curves of Example 1 and Comparative Example 2 are shown below. Figure 1 and Figure 2 As shown.

[0070] (2) Optical performance testing: The resin (15 wt%) obtained in the examples and comparative examples was mixed with an acid-generating agent (DPI-100, 3 wt%), a crosslinking agent (HMMM, 10 wt%), and an organic solvent (propylene glycol phenyl ether, 72 wt%) and shaken until completely dissolved. After filtering through a 0.2 μm PTFE film filter, the anti-reflective coating composition was obtained. The anti-reflective coating composition was spin-coated onto a silicon substrate and then baked at 200 °C for 60 s to form an anti-reflective coating with a thickness of 800 Å. The refractive index (n value) and extinction coefficient (k value) of the anti-reflective coating were tested using an ellipsometer (purchased from Woolman).

[0071] (3) Chemical resistance test: An anti-reflective coating was formed on the silicon substrate according to the method in (2), and then immersed in 1% TMAH alkaline solution and 10% HF acidic solution for 24h respectively. The film thickness before and after immersion was measured, and the film thickness change rate was calculated according to: film thickness change rate (%) = (film thickness before immersion - film thickness after immersion) / film thickness before immersion * 100.

[0072] (4) Flexibility / Elongation at break test: The resins obtained in the examples and comparative examples were used to prepare test specimens (type 2 specimens, length*width*thickness=200*15*1mm) according to GB / T 1040.3-2006 and the elongation at break test was performed on the specimens.

[0073] Table 1

[0074] As shown in Table 1, compared to the comparative examples, the bottom anti-reflective coating resin provided in this invention has a higher onset temperature and a good elongation at break. When used as a bottom anti-reflective coating composition, it has a higher refractive index and a lower extinction coefficient, resulting in better anti-reflective optical performance, a smaller film thickness variation rate, and better chemical resistance. Although the ordinary BARC resin provided in Comparative Example 1 also has a good elongation at break, its onset temperature and refractive index are significantly lower than those of the examples, while its extinction coefficient and film thickness variation rate are significantly higher. Although the traditional heat-resistant polyester BARC resin provided in Comparative Example 2 also has a good elongation at break, its onset temperature is slightly lower than that of the examples, its refractive index is significantly lower, and its extinction coefficient and film thickness variation rate are significantly higher. Compared with Example 1, Comparative Example 3, by using 1,2,3,4-butanetetrol instead of pentaerythritol, although the elongation at break is improved (excessive elongation at break can easily lead to photolithographic pattern distortion, insufficient mechanical stability, and easy generation of defects), the onset temperature and refractive index are significantly reduced, while the extinction coefficient and film thickness variation rate are significantly increased.

[0075] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A method for preparing a bottom antireflective coating resin, characterized by, The preparation method comprises the following steps: S1. terephthalic acid, 5-hydroxyisophthalic acid, alkyl glycol, pentaerythritol, organic solvent I are mixed, and then subjected to a polycondensation reaction in the presence of an inert gas atmosphere and catalyst I until the weight average molecular weight of the obtained polyester prepolymer is 3000-5000 g / mol; S2. the obtained polyester prepolymer is subjected to an ether exchange reaction with an amino resin crosslinking agent in the presence of organic solvent II and catalyst II, and the obtained reaction product is the bottom anti-reflective coating resin.

2. The method of producing a bottom anti-reflective coating resin according to claim 1, wherein The weight average molecular weight of the bottom anti-reflective coating resin is 6000-10000 g / mol, and the PDI is 1.55-1.

96.

3. The method for preparing the bottom anti-reflective coating resin according to claim 1, characterized in that, In step S1, the molar ratio between the terephthalic acid, 5-hydroxyisophthalic acid, alkyl glycol and pentaerythritol is (2.0-3.0):(0.5-1.0):(2.0-3.0):1; Preferably, the amount of the organic solvent I is 40-50 wt% of the total mass of the reaction raw materials, wherein the total mass of the reaction raw materials is the total mass of the terephthalic acid, 5-hydroxyisophthalic acid, alkyl glycol and pentaerythritol; Preferably, the amount of the catalyst I is 0.4-0.6 wt% of the total mass of the reaction raw materials, wherein the total mass of the reaction raw materials is the total mass of the terephthalic acid, 5-hydroxyisophthalic acid, alkyl glycol and pentaerythritol.

4. The method for preparing the bottom anti-reflective coating resin according to claim 1, characterized in that, In step S1, the polycondensation reaction comprises an esterification reaction and a post-polycondensation reaction performed in sequence; Preferably, the conditions of the esterification reaction comprise a temperature of 130-140℃ and a time of 3-5 h; Preferably, the conditions of the post-polycondensation reaction comprise a temperature of 142-150℃ and a time of 1-2 h.

5. The method for preparing the bottom anti-reflective coating resin according to claim 1, characterized in that, In step S1, the method for stopping the reaction comprises controlling the reaction temperature to be 70-80℃ and adding a diluent; preferably, the diluent is at least one selected from the group consisting of methyl 2-hydroxyisobutyrate, ethyl lactate and ethyl acetoacetate.

6. The method of making a bottom antireflective coating resin according to claim 1, wherein In step S2, the amount of the amino resin crosslinking agent is 15-25 wt% of the mass of the polyester prepolymer; Preferably, the conditions of the ether exchange reaction comprise a temperature of 100-110℃ and a time of 0.5-1.5 h.

7. The method for preparing the bottom anti-reflective coating resin according to claim 1, characterized in that, The chemical formula of the alkyl glycol is HO-R-OH, wherein R is a linear or branched alkylene group with 1-5 carbon atoms; Preferably, the organic solvent I and the organic solvent II are each independently at least one selected from the group consisting of anisole, phenetol, diphenyl ether, diethylene glycol butyl ether and propylene glycol phenyl ether; Preferably, the catalyst I and the catalyst II are both acidic catalysts; and the catalyst I and the catalyst II are each independently at least one selected from the group consisting of p-toluenesulfonic acid, methanesulfonic acid, sulfuric acid and phosphoric acid; Preferably, the amino resin crosslinking agent is at least one selected from the group consisting of hexamethylol melamine hexamethylether, hexaethoxymethyl melamine, hexapropoxymethyl melamine, tetramethoxymethyl glycoluril and benzoguanamine.

8. A bottom anti-reflective coating resin prepared by the method of any one of claims 1-7.

9. Use of the bottom anti-reflective coating resin according to claim 8 in a bottom anti-reflective coating composition, characterized in that, The bottom anti-reflective coating composition contains the bottom anti-reflective coating resin of claim 8, an acid generator, a crosslinking agent, and an organic solvent III.

10. Use of the bottom antireflective coating resin of claim 8 for the preparation of a lithographic pattern, characterized in that, The application is used by forming an anti-reflective coating containing the bottom anti-reflective coating resin of claim 8 between a substrate and a photoresist.

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