Photoresist monomer, polymer thereof and photoresist composition

Abstract

The invention relates to the field of photosensitive materials, and discloses a photoresist monomer, a polymer thereof and a photoresist composition. The invention relates to a photoresist composition, which comprises 40%-60% of a photoresist polymer and 0.5%-10% of a photoacid generator, and 20-40% of an organic solvent. Wherein the photoresist polymer is a uniform and compact high-molecular photoresist polymer crosslinked with a siloxy group, and the uniform and compact high-molecular photoresist polymer crosslinked with the siloxy group is obtained by polymerizing a first prepolymer obtained by mixing, polymerizing and modifying methyl methacrylate, hydroxypropyl acrylate and acrylic acid and a second prepolymer obtained by modifying a low-molecular chain segment containing the siloxy group; according to the obtained photoresist, the shrinkage rate is improved, the etching resistance is enhanced, the adsorbability and the adhesion to a substrate are greatly improved, the photoresist is used for a 193nm photoetching process, the optimal sensitivity can reach 0.10 mJ / cm < 2 >, an image is clear, and the edge roughness is good.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photosensitive material of photoresist, in particular to the field of preparation of photosensitive material of photoresist composition for semiconductor devices. BACKGROUND

[0002] In the field of semiconductor manufacturing, the photolithography technology for forming patterns has been developed rapidly, and along with the development, the line width tends to be extremely fine in recent years. Initially, I-ray and G-ray were used in the exposure of photolithography, and the line width was relatively wide. The G / I line photoresist mainly used linear phenolic resin as the main resin, and diazonaphthoquinone as the photosensitizer, and through the photolithography process procedures such as exposure and development, the pattern of the mask plate was transferred and copied to the wafer. The linear phenolic resin has strong resistance to dry and wet etching, but the glass transition temperature of the linear phenolic resin is relatively low, and the heat resistance is insufficient, and the heat resistance temperature of the photoresist required in most microelectronic processing technologies at present is 200°C or even higher. Because the general linear phenolic resin has insufficient heat resistance, the migration of the catalyst is increased in the photolithography process, and it cannot meet the higher resolution circuit devices, and the conventional phenolic resin will deform the photolithography pattern at higher than 140°C, which affects the resolution of the photoresist. In the manufacture of integrated circuits, the resolution of the photoresist directly affects the precision performance of the photolithography device. How to improve the photolithography efficiency and resolution of the photoresist while ensuring the quality of the pattern is the focus of the current development of photoresist products.

[0003] Along with the technical development in recent years, the current photolithography technology uses ArF excimer laser as the exposure light source, and it is necessary to develop new type of photoresist materials for application in the 193nm photolithography process. The conditions that need to be met for designing the 193nm photoresist film forming resin are: low absorption at 193nm, higher optical transparency; higher thermal stability performance, and higher etching resistance due to the continuous reduction of the film thickness.

[0004] The polyacrylate derivative is widely used in the 193nm photoresist main film forming resin, but it has poor adhesion to the substrate, insufficient affinity to the alkali developing solution, and the traditional monomer lacks the required functions of the resist, and at present, the high density liquid fills the so-called liquid immersion exposure method between the substrate and the exposure machine, and further, along with the tendency of the photoresist pattern becoming fine and the film thickness becoming thin, there is an urgent need for monomers with etching resistance.

[0005] A Chinese patent with publication number CN102030643A discloses an acrylic monomer, a polymer and a chemical amplification type photoresist composition. The composition is polymerized from an acrylic monomer having a tert-butoxycarbonyl group at the end, and the photoresist improves the resolution of photolithography, but does not involve the adhesion and etch resistance of the polyacrylate derivative photoresist.

[0006] A Chinese patent with publication number CN111123647B discloses a dry film photoresist, the photopolymerization monomer of which is composed of a long-chain bisacrylate containing a phenyl sulfide and a short-chain acrylate. The dry film photoresist is used to prepare a photosensitive dry film, and has the advantages of fast photosensitivity and high resolution. However, the dry film is used on a printed circuit board, and the problems of poor adhesion and poor etch resistance of the acrylic monomer as a polymer monomer are not solved.

[0007] At present, the mainstream method for improving the polyacrylate derivative photoresist is to introduce a cycloaliphatic monomer for copolymerization, directly introducing a cycloaliphatic structure into the main chain of the polymer, so that it has good etch resistance. However, the preparation method is very complicated. Moreover, it cannot solve the problem of poor adhesion caused by the shrinkage of the polyacrylate derivative.

[0008] Therefore, how to improve the adhesion and etch resistance of the photoresist on the substrate with a simple and effective method while ensuring the quality of the pattern and the efficiency and resolution of photolithography is the focus of the development of the photoresist product. SUMMARY

[0009] In order to solve the above problems, the purpose of the present application is to provide a photoresist monomer and its polymer, so as to solve one or more technical problems existing in the prior art, and at least provide a beneficial choice or create conditions.

[0010] In view of the defects and deficiencies in the background art, the present application provides a photoresist composition which has good adhesion on the substrate and good etch resistance while ensuring the efficiency and resolution of photolithography.

[0011] According to one aspect of the present application, a photoresist monomer is first provided. In order to make the photoresist composition prepared subsequently achieve good performance, the photoresist monomer needs to meet the following conditions: (1) has high corrosion resistance; (2) in order to make the photoresist achieve better resolution, it needs to have good light transmittance at 193 nm wavelength; (3) has good adhesion to the substrate; (4) in order to meet the requirements of the photolithography process, it needs to have a high glass transition temperature.

[0012] A 193nm photoresist is designed with methyl methacrylate, hydroxypropyl acrylate and acrylic acid as comonomers, and the primary principle is to design a photoresist with both etching resistance and lithography performance.

[0013] The reason for choosing methyl methacrylate, hydroxypropyl acrylate and acrylic acid as the comonomers of the photoresist is that acrylic resin is a general term for a kind of high molecular substances polymerized from acrylic acid, acrylate, acrylic acid derivatives or other monomers containing double bonds, and the main chain is C-C bond. Acrylic resin monomers are roughly divided into hard monomers, soft monomers and functional monomers according to their functions. The main difference between hard monomers and soft monomers is the glass transition temperature. The glass transition temperature of hard monomers is generally above 100℃, while the glass transition temperature of soft monomers is generally below 0℃. Hard monomers provide hardness in the resin, while soft monomers improve flexibility and promote film formation. Functional monomers introduce reactive functional groups such as hydroxyl, carboxyl and amino groups into the system.

[0014] Therefore, the combination of different types of monomers can improve the performance of the resin, making it have good hardness and toughness after film formation, and improve the impact resistance. The introduction of different functional groups makes the prepared polymer have different properties. Specifically:

[0015] S001: In a reaction kettle equipped with a stirring paddle, a thermometer and a condenser, methyl methacrylate, hydroxypropyl acrylate and n-dodecanethiol are stirred uniformly, and then slowly heated to 80-100℃ under nitrogen protection. Then, azobisisobutyronitrile is added dropwise as an initiator, and the reaction is carried out for 5-8 hours. Then, acrylic acid is added and the reaction is continued for 1-2 hours to obtain a first prepolymer with an average molecular weight of 10000-20000, and hydroxyl groups are grafted on the side chain of the prepolymer.

[0016] In an acidic environment, the side chain of the acrylic resin undergoes protonation of the tertiary amine group and hydrolysis of the ester group. The former can cause positive repulsion between the polymer chains, which in turn causes the polymer network to relax, the diffusion to increase, and holes to appear in the network. In an alkaline environment, the active group is -COOH, so it is stable in a low pH environment, but it combines with OH- to form a salt in a high pH environment. Due to the mutual repulsion of COO-, the intermolecular gap becomes larger and the structure becomes loose. At the same time, the ester group on the side chain of the acrylic resin can also undergo hydrolysis, resulting in negative repulsion between the polymer chains, which further causes the polymer network to relax and the porosity to increase. This results in different degrees of relaxation of the polymer network, and the use environment of the photoresist requires use in a high pH environment, which causes the shrinkage rate to increase and the polymer network to relax.

[0017] The molecular weight of the system is controlled by using the molecular weight regulator n-dodecanethiol; azobisisobutyronitrile is used as the initiator of the reaction, which decomposes to generate active radicals to make the polymerization reaction proceed; the more n-dodecanethiol is added, the smaller the viscosity of the synthesized water dispersion is, because the more n-dodecanethiol, the faster the chain termination reaction, the smaller the relative molecular mass of the product, and the lower the viscosity. When the amount of n-dodecanethiol exceeds 2%, its viscosity-reducing effect changes little, and when the content is 2.3%, the monomer conversion rate is reduced because too much chain transfer agent consumes a large amount of initiator, therefore, the n-dodecanethiol is 1.5-2.0%, and the azobisisobutyronitrile is 0.5-1.0%.

[0018] The resin is prepared by free radical polymerization of acrylic acid and its ester monomers under the action of an initiator. In the preparation process, hydroxyl and carboxyl functional groups are introduced, the obtained polymer particles have a smaller diameter and a higher degree of polymerization than the polymer without these functional groups, the molecular weight of the polymer can be controlled in the range of 10,000-20,000, and the stability is improved due to the introduction of the functional groups. The polymer provides hydroxyl groups, ester groups, contains functional groups having affinity for developing agents, adhesion to substrates, etching resistance and excellent resolution. If the photoresist contains a relatively high carbon content at this time, it can further improve the etching resistance, but the resin is relatively brittle and the adhesion will be poor, so the mass ratio of methyl methacrylate, hydroxypropyl acrylate and acrylic acid is (6-8):(2-5):(1-3).

[0019] To solve this problem, further, a siloxyl group is introduced, and the improvement of heat resistance can be roughly considered that the heat resistance of siloxane containing an aryl group is better than that of siloxane containing an aliphatic group. The reason is that the aryl group itself has a higher stability than the aliphatic group due to the cyclic structure. In the siloxyl group containing an aliphatic group, the carbon atom content and the thermal stability show a negative correlation, and when the number of carbon atoms increases, the thermal stability of the silicone resin will gradually decrease. For the oxidation stability, due to the large difference in electronegativity between Si and O atoms, the polarity of the bond is large, which shields the connected hydrocarbon group, thereby improving the oxidation stability of the matrix.

[0020] S002, in a reaction kettle equipped with a stirring paddle, a thermometer and a condenser, vinyltrimethoxysilane and anilinemethyltriethoxysilane are mixed with ethanol, stirred uniformly at 30-40°C, a certain amount of deionized water is added as a reaction solvent, and stirred for 1-2 hours until the solution is clear. Vinyltrimethoxysilane and anilinemethyltriethoxysilane are hydrolyzed and decomposed into a mixture of cyclic, linear and crosslinked polymers.

[0021] The amount of ethanol is 0.2-1.5 times the sum of the mass of the vinyltrimethoxysiloxane and the anilinomethyltriethoxysilane. The amount of deionized water is 0.2-1.5 times the sum of the mass of the vinyltrimethoxysiloxane and the anilinomethyltriethoxysilane.

[0022] S003, toluene is added to the hydrolysis product low-molecular mixture in S002, and high-speed stirring is performed for 20 hours at 30-40°C, so that the low-molecular mixture of the cyclic, linear, and crosslinked polymers is broken to obtain a siloxy-containing low-molecular segment, which is denoted as a second prepolymer.

[0023] The amount of toluene is 0.1-0.5 times the mass of the hydrolysis product low-molecular mixture.

[0024] S004, the siloxy-containing second prepolymer and the first prepolymer with a molecular weight of 10000-20000 high-molecular weight are fully stirred at a temperature of 50-60°C, so that the low-molecular segment of the siloxy is crosslinked into the first prepolymer, and a high-molecular crosslinked siloxy photoresist polymer is obtained.

[0025] The siloxy-containing second prepolymer and the first prepolymer are deeply crosslinked to form a photoresist polymer matrix of a siloxy network crosslinked high-molecular acrylic acid polymer.

[0026] The mass ratio of the vinyltrimethoxysiloxane and the anilinomethyltriethoxysilane is 1:(4-8); the mass ratio of the first prepolymer and the second prepolymer is 1:7-9;

[0027] Further, in order to make the crosslinking of the siloxy-containing second prepolymer and the first prepolymer more uniform and dense, the second prepolymer and the first prepolymer need to be modified, specifically as follows:

[0028] S101, the first prepolymer is added to 80% diethylene glycol amine solution at 50-60°C, and stirred uniformly, so that the first prepolymer is fully soaked, and the crosslinked network of the polymer is relaxed.

[0029] The mass ratio of the first prepolymer and the 80% diethylene glycol amine solution is 1:(0.1-0.4);

[0030] S102, the second prepolymer is added to 1000-1500 small-molecular-weight polyether at 50-60°C, so that the siloxy groups are adsorbed by the polar polyether, and a spherical structure molecular liquid with a siloxy group outside and a polyether core inside is obtained.

[0031] The mass ratio of the polyether and the second prepolymer is 1:(2-5);

[0032] S103, the spherical structure molecule liquid with external siloxyl and internal polyether core is added into S101, and is fully stirred to cross-link the low molecular chain segment of siloxyl into the first prepolymer, so that the high molecular photoresist polymer with cross-linked siloxyl is obtained.

[0033] The molecular weight is controlled at 10000-20000, mainly because if the molecular weight of the polymer matrix is too small, the cross-linking network is not enough, so that it cannot load too many small molecular substances, which will cause the prepolymer to be unable to load enough siloxyl, further causing the shrinkage of the polymer to be too high, and the high-temperature resistance cannot be effectively improved, and if the molecular weight is too large, too many cavities are formed after high temperature, so that the adhesion is not enough and the strength is not enough.

[0034] The anilinomethyl triethoxysilane is selected as the source of siloxyl, which can enter the silicon atom on one hand to improve the adhesion of the film, control the shrinkage of the film, and on the other hand can increase the carbon content, however, surprisingly and unexpectedly, it is found that the anilinomethyl triethoxysilane can improve the processability of the photoresist polymer, and further reduce the exposure dose. It is also observed that the high molecular photoresist polymer with cross-linked siloxyl has a significant improvement in thermal flow stability, wherein the photoresist can withstand a post-baking temperature of 180-210°C without affecting the image resolution.

[0035] Further, the mass percentage of the photoresist composition is: photoresist polymer 40%-60%, photoacid generator 0.5%-10%; organic solvent is: 20-50%, and the components are combined.

[0036] The organic solvent in the photoresist composition is an organic solvent that can dissolve the photoresist polymer, has a proper drying rate and provides a uniform and smooth coating after the solvent is evaporated. The solvent includes methyl cellosolve, ethylene glycol ethyl ether acetate, ethylene glycol methyl ether acetate, propylene glycol methyl ether acetate, ethylene glycol monoethyl ether; butyl acetate, amyl acetate and ethyl acetoacetate; acetone, methyl isobutyl ketone, 2-heptanone, cyclohexanone; gamma-butyrolactone, ethyl lactate, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate; these solvents can be used alone or two or more of them can be mixed for use. The amount of the solvent can be determined according to the physical properties of the solvent, i.e. volatility and viscosity, so that the photoresist polymer is dissolved in the solvent to form a uniform film.

[0037] The photoacid generator in the photoresist composition is 1,2,3-trisulfonyloxy methyl benzene, triphenyl sulfonium methane sulfonate, benzoin toluene sulfonate, 1,2-naphthoquinone azide compound; these photoacid generators can be used alone or two or more of them can be mixed for use.

[0038] Furthermore, the preparation method of the photoresist composition is as follows: the photoresist polymer and organic solvent are mixed according to the formula ratio, and shaken in the dark for 30 to 50 hours to fully dissolve it; then the photoacid generator is added, stirred evenly, and filtered with a filter of 0.5 micrometers or less to obtain the photoresist composition.

[0039] Compared with the prior art, the positive and beneficial effects achieved by the present invention are as follows:

[0040] 1) This invention uses methyl methacrylate, hydroxypropyl acrylate, and acrylic acid as polymerizable monomers to prepare a macromolecular matrix for photoresist. Because this matrix consists of linear chains composed of rigid monomers, it possesses a high glass transition temperature, significantly improving the chemical resistance and high-temperature resistance of the photoresist. The prepared photoresist matrix can reduce its absorption of 193nm wavelength light, giving it high transmittance at 193nm, making it suitable for preparing 193nm photoresist compositions.

[0041] 2) This invention improves the C / H ratio of the photoresist polymer by introducing a benzene ring cyclic structure and siloxy groups into the macromolecular matrix of the photoresist. Furthermore, the introduction of silicon results in a uniform and dense film on the substrate, with increased strength and temperature resistance. The photoresist composition prepared using this uniform and dense cross-linked siloxy group-modified polymer not only enhances the adsorption and adhesion of the photoresist to the substrate but also significantly improves its resistance to etching. Moreover, the resulting pattern resolution reaches 39 nm, with clear images and good edge roughness.

[0042] 3) This invention provides a method for preparing a novel cross-linked siloxy-based polymeric photoresist. The novel cross-linked siloxy-based polymeric photoresist is uniformly and densely distributed, improving the shrinkage rate of the matrix. Moreover, the photoresist polymer exhibits excellent solubility in organic solvents and significant improvement in thermal flow stability on the substrate. The photoresist can withstand post-baking temperatures of 170°C to 190°C without affecting image resolution.

[0043] 4) This invention improves the processability of the photoresist polymer by modifying the first and second prepolymers, thereby increasing the photosensitivity of the photoresist to a minimum of 10 mJ / cm. 2 Furthermore, the exposure dose was reduced. Detailed Implementation

[0044] The application will be further described in conjunction with the specific embodiments. It should be understood that these embodiments are only used to illustrate but not to limit the scope of the application. Furthermore, it should be understood that after reading the content of the application, those skilled in the art can make various modifications or changes to the application, and these equivalent forms also fall within the scope defined by the appended claims.

[0045] Example 1

[0046] Firstly, a first prepolymer is prepared, and the preparation method is specifically as follows:

[0047] In a reaction kettle equipped with a stirring paddle, a thermometer, and a condenser, 6 parts of methyl methacrylate, 2 parts of hydroxypropyl acrylate, and 1.5% of n-dodecanethiol are stirred uniformly, and then slowly heated to 100°C under nitrogen protection. Then, 0.5% of azobisisobutyronitrile is added dropwise as an initiator. After fully reacting for 5 hours, 2 parts of acrylic acid is added for further reaction for 2 hours, to obtain the first prepolymer with hydroxyl groups grafted on the side chains.

[0048] The molecular weight and molecular weight distribution of the first prepolymer are tested by GPC. The testing conditions of GPC are as follows: GPC is Waters; the detector is Waters2414 Refractive Index Detector; the chromatographic column is styragel@HR2-4THF 7.8×300mm Column; the mobile phase is THF (1 mL / min); and tetrahydrofuran (THF) is used as the solvent to prepare a copolymer solution of 1 mg / mL of the first prepolymer obtained above. After filtration by using a 0.45 μm filter membrane, GPC analysis is performed, and polystyrene is used as a standard sample to determine the relative molecular weight of the polymer. Finally, the weight average molecular weight of the first prepolymer is measured to be 10642 g / mol, and the molecular weight distribution is 1.63.

[0049] The temperature is lowered to 50°C, 2 parts of an 80% diethanolamine solution is added to 8 parts of the first prepolymer, and stirred uniformly, so that the first prepolymer is fully soaked, and the crosslinked network of the polymer is relaxed, to obtain the modified first prepolymer.

[0050] Then, a second prepolymer is prepared, and the preparation method is specifically as follows:

[0051] In a reaction kettle equipped with a stirring paddle, a thermometer, and a condenser, 1 part of vinyltrimethoxysilane and 6 parts of anilinemethyltriethoxysilane are mixed with 4 parts of ethanol, and stirred uniformly at 40°C. Then, 4 parts of deionized water is added as a reaction solvent, and stirred at room temperature for 1-2 hours until the solution is clear. The vinyltrimethoxysilane and the anilinemethyltriethoxysilane are hydrolyzed and decomposed into a low-molecular mixture of cyclic, linear, and crosslinked polymers.

[0052] The obtained hydrolysis product low molecular mixture is added to 1 part of toluene at 40°C, and stirred at high speed for 20 hours to break the cyclic, linear and cross-linked polymer low molecular mixture to obtain a low molecular siloxyl segment, which is referred to as a low molecular weight second prepolymer;

[0053] The second prepolymer is modified, specifically as follows:

[0054] 4 parts of the second prepolymer are added to 1 part of a small molecular weight polyether with an average molecular weight of 1000 at 60°C to adsorb the siloxyl groups with the polar polyether, thereby obtaining a spherical structure molecular liquid with a siloxyl outer layer and a polyether core;

[0055] Then, a high molecular photoresist polymer cross-linked with siloxyl groups is prepared, specifically as follows:

[0056] 4 parts of the spherical structure molecular liquid with a siloxyl outer layer and a polyether core are added to 36 parts of the swelled and relaxed first prepolymer at a temperature of 60°C, an initiator is added dropwise, and the mixture is fully stirred and reacted for 2-3 hours to cross-link the siloxyl low molecular segment into the first prepolymer, thereby obtaining a uniform and dense high molecular photoresist polymer cross-linked with siloxyl groups.

[0057] Finally, 52% of the high molecular photoresist polymer and 45% of an organic solvent are mixed, and the mixture is shaken in the dark for 30 hours to fully dissolve; then, 3% of a photoacid generator is added, the mixture is stirred uniformly, and filtered through a 0.5 micron filter to obtain a photoresist composition.

[0058] Example 2

[0059] First, the first prepolymer is prepared, specifically as follows:

[0060] In a reaction kettle equipped with a stirring paddle, a thermometer, and a condenser, 8 parts of methyl methacrylate, 5 parts of hydroxypropyl acrylate, and 1.5% of n-dodecanethiol are stirred uniformly, and then slowly heated to 80°C under nitrogen protection; then, an initiator, 1.0% of azobisisobutyronitrile, is added dropwise, and the mixture is fully reacted for 8 hours; then, 1 part of acrylic acid is added, and the mixture is further reacted for 2 hours to obtain the first prepolymer with hydroxyl groups grafted on the side chains.

[0061] The molecular weight and molecular weight distribution of the first prepolymer are tested by GPC, and finally, the weight average molecular weight of the first prepolymer is measured to be 17139 g / mol, and the molecular weight distribution is 1.91.

[0062] The temperature is lowered to 50°C, 3 parts of an 80% diethylene glycol amine solution are added to 8 parts of the first prepolymer, and the mixture is stirred uniformly to fully soak the first prepolymer, and the cross-linked network of the polymer is relaxed to obtain the modified first prepolymer.

[0063] The second prepolymer is prepared, specifically as follows:

[0064] In a reaction vessel equipped with a stirring paddle, thermometer, condenser, 1 part of vinyl trimethoxysilane and 8 parts of aniline methyl triethoxysilane were mixed with 4 parts of ethanol, stirred uniformly at 40°C, 4 parts of deionized water was added as the reaction solvent, stirred at room temperature for 2 hours until the solution was clear, the vinyl trimethoxysilane and aniline methyl triethoxysilane were hydrolyzed and decomposed into a low molecular mixture of cyclic, linear and cross-linked polymers;

[0065] The obtained low molecular mixture of hydrolysis products was added to 2 parts of toluene at 40°C, and stirred at high speed for 20 hours, the low molecular mixture of cyclic, linear and cross-linked polymers was broken to obtain a low molecular chain segment containing siloxyl, which was recorded as a second prepolymer with low molecular weight;

[0066] The second prepolymer was modified, specifically:

[0067] 4 parts of the second prepolymer were added to 2 parts of a small molecular weight polyether with an average molecular weight of 1500 at 60°C, so that the siloxyl group was adsorbed by the polar polyether, and a spherical structure molecular liquid with a siloxyl outer layer and a polyether core was obtained;

[0068] Then a high molecular photoresist polymer cross-linked with siloxyl was prepared, specifically:

[0069] 4 parts of the spherical structure molecular liquid with a siloxyl outer layer and a polyether core were added to 28 parts of the first prepolymer swollen and relaxed at a temperature of 50°C, an initiator was added dropwise, stirred thoroughly, and reacted for 3 hours, so that the low molecular chain segment of siloxyl was cross-linked into the first prepolymer, and a uniform and dense high molecular photoresist polymer cross-linked with siloxyl was obtained.

[0070] Finally, 41% of the high molecular photoresist polymer and 49% of the organic solvent were mixed, and the mixture was shaken in the dark for 30 hours to make it fully dissolved; then 10% of a photoacid generator was added, stirred uniformly, filtered with a 0.2 micron filter, and a photoresist composition was obtained.

[0071] Example 3

[0072] First, the first prepolymer was prepared, and the preparation method was specifically:

[0073] In a reaction vessel equipped with a stirring paddle, thermometer, condenser, 7 parts of methyl methacrylate, 4 parts of hydroxypropyl acrylate, and 1.5% of n-dodecanethiol were stirred uniformly, heated slowly to 80°C under nitrogen protection, then 1.0% of azobisisobutyronitrile was added dropwise as an initiator, and reacted thoroughly for 8 hours, then 3 parts of acrylic acid was added and reacted for another 2 hours, and the first prepolymer with hydroxyl groups grafted on the side chain was obtained;

[0074] The molecular weight and molecular weight distribution of the first prepolymer were tested using GPC. Ultimately, the weight average molecular weight of the first prepolymer was measured to be 14811 g / mol, and the molecular weight distribution was 2.01.

[0075] The temperature was lowered to 50°C, 1 part of an 80% diethylene glycol amine solution was added to 8 parts of the first prepolymer, and the first prepolymer was fully soaked by stirring until the crosslinked network of the polymer relaxed, obtaining the modified first prepolymer.

[0076] A second prepolymer was then prepared by the following method:

[0077] In a reaction kettle equipped with a stirring paddle, a thermometer, and a condenser, 1 part of vinyltrimethoxysilane and 4 parts of anilinemethyltriethoxysilane were mixed with 1 part of ethanol and stirred uniformly at 40°C. 2 parts of deionized water were added as a reaction solvent, and the mixture was stirred at room temperature for 2 hours until the solution was clear. The vinyltrimethoxysilane and anilinemethyltriethoxysilane were hydrolyzed and decomposed into a low molecular mixture of cyclic, linear, and crosslinked polymers.

[0078] The obtained low molecular mixture of hydrolysis products was added to 1 part of toluene at 40°C, and high-speed stirring was performed for 20 hours. The low molecular mixture of cyclic, linear, and crosslinked polymers was broken to obtain a low molecular segment containing siloxyl groups, which was denoted as a low molecular weight second prepolymer.

[0079] The second prepolymer was modified by the following method:

[0080] 5 parts of the second prepolymer were added to 1 part of a small molecular weight polyether with an average molecular weight of 1200 at 60°C, so that the siloxyl groups were adsorbed by the polar polyether, obtaining a spherical structure molecular liquid with a siloxyl group outer layer and a polyether core.

[0081] A high molecular photoresist polymer crosslinked with siloxyl groups was then prepared by the following method:

[0082] 4 parts of the spherical structure molecular liquid with a siloxyl group outer layer and a polyether core were added to 32 parts of the first prepolymer that was swelled and relaxed at a temperature of 50°C, and an initiator was added dropwise while stirring thoroughly. The reaction was performed for 3 hours, so that the low molecular segment of siloxyl groups was crosslinked into the first prepolymer, obtaining a uniform and dense high molecular photoresist polymer crosslinked with siloxyl groups.

[0083] Finally, 35% of the high molecular photoresist polymer and 58% of an organic solvent were mixed, and the mixture was shaken in the dark for 30 hours to ensure complete dissolution. Then, 7% of a photoacid generator was added, and the mixture was stirred uniformly and filtered through a 0.2 micron filter, obtaining a photoresist composition.

[0084] Example 4

[0085] A first prepolymer was first prepared by the following method:

[0086] In a reaction kettle equipped with a stirring paddle, a thermometer, a condenser, 6 parts of methyl methacrylate, 2 parts of hydroxypropyl acrylate, 1.5% of n-dodecanethiol were stirred uniformly, and slowly warmed to 80°C under nitrogen protection, then 1.0% of azobisisobutyronitrile was added dropwise as an initiator, and fully reacted for 8 hours. Then 2 parts of acrylic acid was added for further reaction for 2 hours to obtain a first prepolymer with hydroxyl groups grafted on the side chain thereof;

[0087] The molecular weight and molecular weight distribution of the first prepolymer were tested by GPC. Finally, the weight average molecular weight of the first prepolymer was measured to be 18974 g / mol, and the molecular weight distribution was 1.97.

[0088] The temperature was lowered to 50°C, 2 parts of 80% diethylene glycol amine solution was added to 8 parts of the first prepolymer, and stirred uniformly to fully soak the first prepolymer. The crosslinked network of the polymer was relaxed to obtain a modified first prepolymer.

[0089] A second prepolymer was prepared by the following method:

[0090] In a reaction kettle equipped with a stirring paddle, a thermometer, a condenser, 1 part of vinyl trimethoxysilane and 6 parts of aniline methyl triethoxysilane were mixed with 3 parts of ethanol and stirred uniformly at 40°C. 3 parts of deionized water was added as a reaction solvent, and stirred at room temperature for 2 hours until the solution was clear. The vinyl trimethoxysilane and aniline methyl triethoxysilane were hydrolyzed and decomposed into a mixture of cyclic, linear and crosslinked low molecular polymers;

[0091] The obtained hydrolysis product low molecular mixture was added to 2 parts of toluene at 40°C, and stirred at high speed for 20 hours. The cyclic, linear and crosslinked low molecular mixture was broken to obtain a low molecular segment containing siloxyl, which was recorded as a low molecular weight second prepolymer;

[0092] The second prepolymer was modified as follows:

[0093] 4 parts of the second prepolymer was added to 1 part of a small molecular weight polyether with an average molecular weight of 1000 at 60°C, so that the siloxyl group was adsorbed by the polar polyether to obtain a spherical structure molecular liquid with a siloxyl outer layer and a polyether core;

[0094] Then a high molecular photoresist polymer crosslinked with siloxyl was prepared as follows:

[0095] 4 parts of the spherical structure molecular liquid with a siloxyl outer layer and a polyether core was added to 36 parts of the first prepolymer which was swelled and relaxed at a temperature of 50°C, an initiator was added dropwise, and fully stirred for 3 hours to crosslink the siloxyl low molecular segment into the first prepolymer to obtain a uniform and dense high molecular photoresist polymer crosslinked with siloxyl.

[0096] Finally, 40% of the high molecular photoresist polymer and 57% of the organic solvent were mixed, shaken in the dark for 30 hours to fully dissolve, then 3% of the photoacid generator was added, stirred evenly, filtered with a 0.4 micron filter, and a photoresist composition was obtained.

[0097] Comparative Example 1: The first prepolymer and the second prepolymer were replaced with equal amounts of unmodified first prepolymer and second prepolymer respectively, and the rest was the same as Example 1.

[0098] Comparative Example 2: The first prepolymer was replaced with equal amounts of unmodified first prepolymer, and the rest was the same as Example 1.

[0099] Comparative Example 3: The second prepolymer was replaced with equal amounts of unmodified second prepolymer, and the rest was the same as Example 1.

[0100] Comparative Example 4: No second prepolymer was added, and equal amounts of modified first prepolymer was used instead, and the rest was the same as Example 1.

[0101] Comparative Example 5: The photoresist product in Example 4 of Chinese Patent CN113214429B;

[0102] The photoresist composition prepared in Example 1 and the product involved in Comparative Example 5 were spin-coated on the upper part of a silicon wafer, and L / S pattern exposure was performed using a 193 photolithography machine. After coating, exposure, development, the time required for PEB (post-exposure bake) before development was recorded, and the post-exposure bake temperature was 200°C. The adhesion test was performed according to GB / T6739-2006 standard, and the results are shown in Table 1. As can be seen from Table 1, the PEB time of the photoresist composition in the present application is significantly less than that of the product in Comparative Example 5, and the performance of the film after development is better.

[0103] Table 1: Performance test results of photoresist composition

[0104] Product Product Tack free time (s) Through dry time (h) PEB time (s) Adhesion (scale) Example 2 6 0.1 22 3 Comparative Example 5 5 0.1 38 2

[0105] The photoresist compositions prepared in Examples 1-4 and the photoresist compositions involved in Comparative Examples 1-5 were spin-coated on the upper part of a silicon wafer, and the adhesion to the substrate, photosensitivity and resolution in the process of forming the photoresist pattern or after the process were evaluated. As for the adhesion, the adhesion state of the photoresist pattern formed after development to the substrate, i.e. line and space (L / S) pattern, was observed for evaluation. In addition, when the exposure amount formed by the line and space (L / S) pattern with a line width of 1:1 was used as the optimum exposure amount, the optimum exposure amount could be the photosensitivity, and the minimum pattern size that had been resolved could be the resolution, and the smaller the size identified, the better the resolution. In this case, the results of the photosensitivity and resolution are shown in Table 2 below. The acid resistance test standard refers to GB1785-79; the resolution test standard refers to GB / T29556-2013. Adhesion test: after the film formation of the photoresist composition on the substrate, the pattern formed was observed by scanning electron microscopy, and no peeling and glue inversion phenomenon was observed, which proved that the adhesion was good. If glue inversion, peeling, line deformation and other phenomena occurred, it proved that the adhesion was unqualified.

[0106] Table 2 Application effect of photoresist composition

[0107]

[0108] As can be seen from Table 2, the comprehensive performance of the photoresist composition prepared in Example 1 is the best, and compared with the results of Comparative Examples 1-5, the performance of the photoresist composition prepared by the application is more excellent, and the photosensitivity of the composition of Examples 1 to 4 is more excellent than that of the composition of Comparative Examples 1 to 5. In addition, the resolution of the composition of Examples 1 to 4 is more excellent than that of the composition of Comparative Examples 1 to 4. It can be seen that the improvement of photosensitivity and resolution is the result of the joint action of the spherical structure molecular liquid with siloxyl group in the core and the high polymer substrate. At the same time, the introduction of siloxyl group enhances the adhesion to the substrate and improves the shrinkage of the photoresist composition. Thus, better resolution and photosensitivity are obtained, and the exposure amount is reduced.

[0109] The above description is only to illustrate the technical solutions of the present application and not to limit the present application. Any equivalent modification and change of the technical solutions of the present application made by those skilled in the art without departing from the overall concept of the present application shall still fall within the scope of the present application.

Claims

1. A photoresist composition characterized by: The mass percentage of each component of the photoresist composition is: photoresist polymer 40-60%, photoacid generator 0.5-10%; organic solvent is 20-50%; The photoresist polymer is a 193nm photoresist photosensitive material polymerized from photoresist monomers; the photoresist monomers are a mixture of methyl methacrylate, hydroxypropyl acrylate and acrylic acid.

2. The photoresist composition of claim 1, wherein The photoresist polymer is a high-molecular photoresist polymer crosslinked with siloxyl groups, and the preparation method is as follows: S001: in a reaction kettle equipped with a stirring paddle, a thermometer and a condenser, methyl methacrylate, hydroxypropyl acrylate and n-dodecanethiol are stirred uniformly, and then slowly heated to 80-100℃ under nitrogen protection, followed by dropwise addition of initiator azobisisobutyronitrile, and fully reacted for 5-8 hours, then added with acrylic acid and reacted for 1-2 hours to obtain a first prepolymer with an average molecular weight of 10000-20000 and grafted with hydroxyl groups on the side chain; S002: in a reaction kettle equipped with a stirring paddle, a thermometer and a condenser, vinyltrimethoxysilane and anilinemethyltriethoxysilane are mixed with ethanol and stirred uniformly at 30-40℃, and then a certain amount of deionized water is added as a reaction solvent, and stirred for 1-2 hours until the solution is clear, and the vinyltrimethoxysilane and anilinemethyltriethoxysilane are hydrolyzed and decomposed into a low-molecular mixture of cyclic, linear and crosslinked polymers; S003: the low-molecular mixture of hydrolysis products in S002 is added to toluene, and stirred at high speed for 20 hours at 30-40℃, and the low-molecular mixture of cyclic, linear and crosslinked polymers is broken to obtain a low-molecular chain segment containing siloxyl groups, which is recorded as a second prepolymer with a low molecular weight; S004: the second prepolymer with a low molecular weight and the first prepolymer with a high molecular weight of 10000-20000 are added with an initiator at a temperature of 50-60℃, fully stirred, and reacted for 2-3 hours to crosslink the low-molecular chain segment of siloxyl groups into the first prepolymer, and obtain a high-molecular photoresist polymer crosslinked with siloxyl groups.

3. The photoresist composition of claim 2, wherein The second prepolymer and the first prepolymer are modified to obtain a uniform and dense high-molecular photoresist polymer crosslinked with siloxyl groups, and the modification is as follows: S101: the first prepolymer is added into 80% diethylene glycol amine at 50-60℃, stirred uniformly, and the first prepolymer is fully soaked, and the crosslinked network of the polymer is relaxed; S102: the second prepolymer is added into 1000-1500 small-molecular-weight polyether at 50-60℃, so that the siloxyl groups are adsorbed by the polar polyether to obtain a spherical structure molecular liquid with a core of polyether and a shell of siloxyl groups; S103: the spherical structure molecular liquid with a core of polyether and a shell of siloxyl groups is added into S101, and fully stirred to crosslink the low-molecular chain segment of siloxyl groups into the first prepolymer, and obtain a uniform and dense high-molecular photoresist polymer crosslinked with siloxyl groups.

4. The photoresist composition of claim 1 wherein The organic solvent in the photoresist composition is an organic solvent that can dissolve the components, has a proper drying rate, and provides a uniform and smooth coating after solvent evaporation; the solvent includes methyl cellosolve, ethylene glycol ethyl ether acetate, ethylene glycol methyl ether acetate, propylene glycol methyl ether acetate, ethylene glycol monoethyl ether; butyl acetate, amyl acetate and ethyl acetoacetate; acetone, methyl isobutyl ketone, 2-heptanone, cyclohexanone; gamma-butyrolactone, ethyl lactate, methyl 2-hydroxypropionate; the solvents can be used alone or two or more of them can be mixed.

5. The photoresist composition of claim 1, wherein The photoacid generator in the photoresist composition is 1,2,3-trisulfonyloxy methyl benzene, triphenyl sulfonium methane sulfonate, benzoin toluene sulfonate, 1,2-naphthoquinone azide compound; the photoacid generators can be used alone or two or more of them can be mixed.

6. The photoresist composition of claim 2, wherein The mass ratio of methyl methacrylate, hydroxypropyl acrylate and acrylic acid is (6-8):(2-5):(1-3); the mass ratio of vinyl trimethoxysilane and aniline methyl triethoxysilane is 1:(4-8).

7. The photoresist composition of claim 2 or 3, wherein The mass ratio of the second prepolymer and the first prepolymer is 1:7-9.

8. The photoresist composition of claim 1, wherein The preparation method of the photoresist composition is as follows: the photoresist polymer and the organic solvent are mixed according to the formula proportion, and are shaken for 30-50 hours in the dark to make them fully dissolved; then the photoacid generator is added, and is stirred uniformly, and is filtered with a 0.2-0.5 μm filter membrane to obtain the photoresist composition.

9. A photoresist monomer characterized by: The photoresist monomer is applied to the photoresist polymer as claimed in any one of claims 1-6.

10. A photoresist polymer characterized by: The photoresist polymer is applied to the photoresist composition as claimed in any one of claims 1-6.

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