KrF resins, methods of making the same, and chemically amplified photoresists

Abstract

The application provides a KrF resin, a preparation method thereof and a chemical amplification photoresist, and relates to the field of semiconductors. The KrF resin has a general structure as follows: the preparation method of the KrF resin comprises the following steps: mixing raw materials including 4-acetyloxy styrene, a first monomer compound, a second monomer compound and an initiator, and performing a first reaction; then adding an ammonium acetate-water suspension into the system, and performing a second reaction to obtain the KrF resin; the first monomer compound is a compound comprising a high ultraviolet absorption group, and the second monomer compound is a compound comprising a low-activation-energy deprotection acidic group. The chemical amplification photoresist comprises the KrF resin. The KrF resin provided by the application has the characteristics of controllable UV absorption and low deprotection activation energy. The chemical amplification photoresist has the ability to obtain good developing pattern results under different transmittance requirements.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor, in particular to a KrF resin, a preparation method thereof and a chemically amplified photoresist. BACKGROUND

[0002] Semiconductor-related advanced lithography materials and process technology (KrF, ArF, EUV, etc.) is an important direction being developed by various countries, and also represents the current most advanced micro-nano device construction level. With the demand of micro-nano devices for higher circuit density, reducing the minimum feature size of the basic structural unit is a direct and effective method. And reducing the minimum feature size usually requires more sophisticated, higher resolution process and materials, and the usual approach is to develop smaller wavelength lithography materials and process technology (for example, from i-line-365nm to KrF-248nm transition). But when the exposure wavelength becomes shorter, it brings obvious practical problems: first, the actual number of photons decreases with the same energy dose, so higher exposure is needed to obtain equivalent photochemical response; second, the output efficiency of deep ultraviolet lithography machine becomes lower due to shorter wavelength and more complex instrument structure.

[0003] In order to improve the exposure sensitivity under short wavelength and enhance the photochemical response efficiency, the solution is to introduce the concept of chemical amplification: U.S. Patent No. 4491628 and other patent documents mention chemical amplification type photoresist compositions. Positive chemical amplification type photoresist usually contains photoacid generator (PAG) and acid-sensitive polymer. The role of photoacid generator is to generate protons during the exposure process. During the heating process of the photoresist, the protons cause the deprotection of the acid-sensitive side chain groups of the acid-sensitive polymer, and the protons are not consumed in the deprotection cracking reaction, but can continue to catalyze the next reaction, thus playing a photochemical efficiency role, which is called chemical amplification technology; and the polymer with acid-sensitive side chain or side group can be deprotected to form alkali-soluble groups such as carboxyl under acid catalysis, so that the polymer can be dissolved in the alkali developing solution, thereby realizing the purpose of positive development. With the introduction of the concept of chemical amplification, the basic problem of deep ultraviolet lithography theory and material design is solved, but with it comes the different requirements of photoresist material performance under different application scenarios: that is, the photoresist material needs to consider high photosensitivity, etch resistance, stability, high pattern quality (edge uniformity, standing wave, T-top, under cut, etc.) at the same time, therefore, researchers need to make targeted design and improvement according to different application scenarios and requirements to meet the requirements of different application scenarios.

[0004] Semiconductor related photoresist products usually have specific requirements for the application film thickness, that is, different application scenarios have different requirements for the thickness of the photoresist, and in the development process of the photoresist, different thicknesses mean that different transmittances need to be adjusted accordingly (the transmittance needs to be controlled within a suitable range according to different film thicknesses and application scenarios, and too large or too small will affect the actual performance of the photoresist), which requires researchers to adjust the transmittance of the photoresist accordingly while maintaining the basic material structure. The structure and amount of the resin and the photoacid generator in the chemical amplification system have a significant impact on the transmittance of the system, but small adjustments in the structure and amount of the photoacid generator can greatly affect the resolution, photosensitivity, and pattern quality of the photoresist. Therefore, the overall transmittance is usually adjusted by changing the structure of the semiconductor related resin, and US7632630 introduces high-absorption dye molecules into the resin structure to reduce the ultraviolet absorption of the resin and reduce the transmittance. Another trend in the development of semiconductor photoresist is to reduce the activation energy of the acid-sensitive deprotection group, thereby reducing the PEB process temperature, thereby minimizing the pattern etching problem in the non-exposed area due to the diffusion of photoacid, improving the pattern edge straightness, and improving the image blur problem. US6485887 improves the development effect and other properties by using a lower activation energy ECPMA monomer.

[0005] Therefore, the development of related resins has become one of the focuses of research and development. SUMMARY

[0006] The purpose of the present application is to provide a KrF resin and its preparation method and a chemical amplification type photoresist to solve the above problems.

[0007] To achieve the above purpose, the following technical solutions are adopted in the present application:

[0008] A KrF resin, the general structure of which is:

[0009]

[0010] wherein R 1 , R 2 , and R 3 are each independently H atom, halogen atom, alkyl or alkoxy group with 1-6 carbon atoms;

[0011] R1 is a hydroxyl group, R2 is a high ultraviolet absorption group, and R3 is a low activation energy deprotection acid group;

[0012] x, y, and z respectively represent the proportion of different types of monomers in the KrF resin, 0

[0013] According to different application scene requirements, the ratio between monomers can be easily regulated, thus realizing higher application flexibility.

[0014] Preferably, the high ultraviolet absorption group comprises any of the groups shown in the following structures:

[0015]

[0016] The low activation energy deprotection acidic group comprises any of the groups shown in the following structures:

[0017]

[0018] Preferably, the weight average molecular weight of the KrF resin is 1000-100000.

[0019] Preferably, the weight average molecular weight of the KrF resin is 2000-50000.

[0020] From the consideration of final photoresist resolution and other performances, the further preferred range is 2000 to 50000.

[0021] The application also provides a preparation method of the KrF resin, comprising:

[0022] Mixing raw materials including 4-acetyloxy styrene, a first monomer compound, a second monomer compound and an initiator, performing a first reaction; then adding ammonium acetate-water suspension into the system, performing a second reaction, to obtain the KrF resin;

[0023] The first monomer compound is a compound comprising a high ultraviolet absorption group, and the second monomer compound is a compound comprising a low activation energy deprotection acidic group.

[0024] Preferably, the first monomer compound comprises any of the following compounds:

[0025]

[0026] The second monomer compound comprises any of the following compounds:

[0027]

[0028] The application also provides a chemically amplified photoresist comprising the KrF resin.

[0029] Preferably, the KrF resin accounts for 5%-50% of the total mass of the photoresist.

[0030] Preferably, the solid content of the photoresist is 5wt%-50wt%.

[0031] The solid content refers to the proportion of the sum of the mass of all substances other than the solvent in the chemically amplified photoresist in the chemically amplified photoresist.

[0032] If the solid content is too low, the continuity and uniformity of the film during film formation of the chemically amplified photoresist will be affected, and if the solid content is too high, the viscosity will be too high, which can cause problems such as air bubbles during film coating, poor flatness, etc.

[0033] Optionally, the proportion of the KrF resin in the total mass of the photoresist can be 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, or any value between 5% and 50%; the solid content of the photoresist can be 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%, 50wt%, or any value between 5wt% and 50wt%.

[0034] Preferably, the chemically amplified photoresist further comprises an organic solvent;

[0035] Preferably, the organic solvent comprises an ether, an ester, a ketone, or a hydroxyl-containing solvent;

[0036] Preferably, the organic solvent comprises at least one of propylene glycol methyl ether acetate (PGMEA), cyclopentanone, cyclohexanone, ethyl lactate, butyl acetate, 2-ethoxyethanol, and 3-ethoxypropyl acetate.

[0037] Preferably, the chemically amplified photoresist further comprises a leveling agent;

[0038] Preferably, the leveling agent comprises a fluorine-containing surfactant and / or a surfactant containing a polyethylene glycol structure;

[0039] Preferably, the leveling agent accounts for 0.001%-1% of the total mass of the photoresist.

[0040] The leveling agent helps to improve the degree of planarization of the thin film, the adhesion between the photoresist compound and the substrate, and reduce the residual film after development, etc.

[0041] Optionally, the proportion of the leveling agent in the total mass of the photoresist can be 0.001%, 0.005%, 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, or any value between 0.001% and 1%.

[0042] Preferably, the photoresist further comprises an acid quencher;

[0043] Preferably, the acid quencher comprises at least one of tetrabutylammonium hydroxide (TBAH), tetrabutylammonium hydroxide ethyl lactate (TBAL), TBAL triisopropanolamine, Trogers Base, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU).

[0044] Preferably, the acid quencher accounts for 0.001%-2% of the total mass of the photoresist.

[0045] Optionally, the acid quencher can account for 0.001%, 0.005%, 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, or 0.001%-2% of the total mass of the photoresist.

[0046] Preferably, the chemically amplified photoresist further comprises a photoacid generator.

[0047] Preferably, the photoacid generator comprises a sulfonium salt and / or an iodonium salt.

[0048] Preferably, the sulfonium salt comprises one or more of the compounds shown in the following structures:

[0049]

[0050] Preferably, the iodonium salt comprises one or more of the compounds shown in the following structures:

[0051]

[0052] Preferably, the photoacid generator accounts for 0.05%-10% of the total mass of the photoresist.

[0053] Optionally, the photoacid generator can account for 0.05%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any value between 0.05%-10% of the total mass of the photoresist.

[0054] Compared with the prior art, the application has the following advantages:

[0055] The KrF resin provided by the application contains high ultraviolet absorption groups and low activation energy deprotection acidic groups, so that the transmittance of the photoresist in the case of thin film thickness can be controlled, and low acid deprotection activation energy is also considered, so that the PEB processing temperature is reduced, and the resolution and edge placement are improved.

[0056] The method of KrF resin provided in the application is prepared by reacting 4-acetyloxy styrene, a first monomer compound, a second monomer compound under the action of an initiator, and then quenching the reaction by an ammonium acetate-water suspension to obtain a KrF resin containing a high ultraviolet absorption group and a low activation energy deprotection acidic group; the method is simple in operation and low in cost.

[0057] The chemically amplified photoresist provided in the application is developed by using the KrF resin, and the photoresist with controllable transmittance and excellent pattern morphology is realized. BRIEF DESCRIPTION OF DRAWINGS

[0058] In order to more clearly illustrate the technical solutions of the embodiments of the application, the drawings needed to be used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some of the embodiments of the application, and therefore should not be regarded as limiting the scope of the application.

[0059] Figure 1 The curve of the photoetching performance test result is for PEB temperature of 90℃;

[0060] Figure 2 The curve of the photoetching performance test result is for PEB temperature of 110℃;

[0061] Figure 3 The photo is for the influence of different activation energy monomers on the edge neatness of development. DETAILED DESCRIPTION

[0062] As used herein:

[0063] “Prepared from” is synonymous with “comprising”. The terms “comprising”, “including”, “having” “with” “contain” or any other similar forms are intended to cover non-exclusive inclusions. For example, a composition, step, method, article or device comprising the listed elements does not necessarily limit to only those elements, but can include other elements not explicitly listed or inherent to such composition, step, method, article or device.

[0064] The conjunction “consisting of” excludes any unrecited elements, steps or components. If used in the claims, this phrase will close the claims to the inclusion of materials not specifically recited, except for impurities ordinarily associated with the recited materials. When the phrase “consisting of” appears in a clause of the body of the claim, it limits the clause to only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0065] When expressing amounts, concentrations, or other values or parameters of a range, preferably a range, or a series of upper preferred values and lower preferred values, it is to be understood that the disclosure specifically envisions all ranges formed from any of the upper values or preferred values with any of the lower values or preferred values, even if that range is not expressly disclosed. For example, it is to be understood that the described ranges include the range "1-5," the ranges "1-4," "1-3," "1-2," "1-2 and 4-5," "1-3 and 5," etc. When numerical ranges are described herein, unless the context indicates otherwise, the range is intended to include both the upper and lower values, and all integers and fractions within that range.

[0066] In these examples, the parts and percentages described are by mass, unless otherwise indicated.

[0067] "Parts by mass" refers to a basic unit of measurement that represents the proportional relationship of the mass of multiple components, 1 part can represent any unit mass, such as 1 g, 2.689 g, etc. If we say that the mass of component A is a parts, and the mass of component B is b parts, it means that the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it means that the mass of component A is aK, and the mass of component B is bK (K is an arbitrary number, indicating a multiple factor). It should not be misunderstood that, unlike parts by mass, the sum of the parts by mass of all components is not limited to 100 parts.

[0068] "And / or" is used to indicate that one or both of the described conditions can occur, for example, A and / or B includes (A and B) and (A or B).

[0069] The embodiments of the present application will be described in detail below with specific examples, but those skilled in the art will understand that the following examples are only for illustration of the present application, and should not be regarded as limiting the scope of the present application. The specific conditions are not specified in the examples, and are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not specified by the manufacturer, and are conventional products that can be purchased on the market.

[0070] The reagents used in the examples of the present application were purchased from the National Pharmaceutical Group Reagent Company, Sigma-Aldrich Company, and Bailingwei Reagent Company, respectively.

[0071] Example 1

[0072] This example provides a KrF resin, the structural formula of which is as follows:

[0073]

[0074] The preparation method is as follows:

[0075] Take 25 g (0.15 mol) of 4-acetoxyphenylstyrene, 7.92 g (0.05 mol) of 1-vinylnaphthalene, 9.36 g (0.05 mol) of 1-ethylcyclopentyl methacrylate into a 250 ml three-necked flask under nitrogen, then add 100 ml of tetrahydrofuran to dissolve, and bubble nitrogen to remove oxygen for half an hour under stirring; take 3.28 g (0.014 mol) of azobisdimethyl isobutyrate (AIBME) to dissolve in 10 ml of acetonitrile, then slowly drop the AIBME / acetonitrile solution into the three-necked flask solution, and reflux for 24 hours after dropping.

[0076] Take 23.76 g (0.31 mol) of ammonium acetate, add 6 ml of deionized water, slowly drop the ammonium acetate / water suspension into the previous reaction solution, and stir for 18 hours at room temperature under nitrogen protection.

[0077] After the reaction is completed, pour the reaction solution into 1 L of deionized water, stir and precipitate for 2 hours, filter, wash the precipitated resin with a large amount of deionized water, and vacuum dry at 50°C to obtain 30.3 g of white solid resin sample with a yield of 86%, M w : 11000.

[0078] Example 2

[0079] This example provides a KrF resin with the following structural formula:

[0080]

[0081] The preparation method is as follows:

[0082] Take 25 g (0.15 mol) of 4-acetoxyphenylstyrene, 10.2 g (0.05 mol) of 9-vinylanthracene, and 9.36 g (0.05 mol) of 1-ethylcyclopentyl methacrylate into a 250 ml three-necked flask under nitrogen, then add 100 ml of tetrahydrofuran to dissolve, and bubble nitrogen to remove oxygen for half an hour under stirring; take 3.28 g (0.014 mol) of azobisdimethyl isobutyrate (AIBME) to dissolve in 10 ml of acetonitrile, then slowly drop the AIBME / acetonitrile solution into the three-necked flask solution, and reflux for 24 hours after dropping.

[0083] Take 23.76 g (0.31 mol) of ammonium acetate, add 6 ml of deionized water, slowly drop the ammonium acetate / water suspension into the previous reaction solution, and stir for 18 hours at room temperature under nitrogen protection.

[0084] After the reaction is completed, the reaction solution is poured into 1 L of deionized water, stirred and precipitated for 2 hours, filtered, and the obtained resin is washed with a large amount of deionized water and dried at 50°C under vacuum to obtain 31.9 g of a white solid resin sample with a yield of 85% and Mw= 12000. w : 11500.

[0085] Example 3

[0086] This example provides a KrF resin having the following structural formula:

[0087]

[0088] The preparation method thereof is as follows:

[0089] Take 25 g (0.15 mol) of 4-acetyloxy styrene, 11.4 g (0.05 mol) of 1-vinyl pyrene, and 9.36 g (0.05 mol) of 1-ethyl cyclopentyl methyl methacrylate, and add them into a 250 ml three-necked flask under a nitrogen environment, then add 100 ml of tetrahydrofuran to dissolve, and bubble nitrogen to remove oxygen for half an hour under stirring; take 3.28 g (0.014 mol) of azobisdimethyl isobutyrate (AIBME), dissolve it in 10 ml of acetonitrile, then slowly drop the AIBME / acetonitrile solution into the three-necked flask solution, and after the dropping is completed, reflux the reaction for 24 hours.

[0090] Take 23.76 g (0.31 mol) of ammonium acetate, add 6 ml of deionized water, slowly drop the ammonium acetate / water suspension into the previous reaction solution, and stir under nitrogen protection at room temperature for 18 hours.

[0091] After the reaction is completed, the reaction solution is poured into 1 L of deionized water, stirred and precipitated for 2 hours, filtered, and the obtained resin is washed with a large amount of deionized water and dried at 50°C under vacuum to obtain 31.9 g of a white solid resin sample with a yield of 85% and Mw= 12000. w : 11500.

[0092] Example 4

[0093] This example provides a KrF resin having the following structural formula:

[0094]

[0095] The preparation method thereof is as follows:

[0096] Take 25 g (0.15 mol) of 4-acetoxyphenylstyrene, 11.4 g (0.05 mol) of 1-vinylpyrene, 11.2 g (0.05 mol) of 1-ethylcycloheptylmethyl methacrylate, respectively, into a 250 ml three-necked flask under nitrogen, then add 100 ml of tetrahydrofuran to dissolve, and bubble nitrogen to remove oxygen for half an hour under stirring; take 3.28 g (0.014 mol) of azobisdimethyl isobutyrate (AIBME) to dissolve in 10 ml of acetonitrile, then slowly drop the AIBME / acetonitrile solution into the three-necked flask solution, and reflux for 24 hours after dropping.

[0097] Take 23.76 g (0.31 mol) of ammonium acetate, add 6 ml of deionized water, slowly drop the ammonium acetate / water suspension into the post-reaction solution, and stir for 18 hours at room temperature under nitrogen protection.

[0098] After the reaction is completed, pour the reaction solution into 1 L of deionized water, stir and precipitate for 2 hours, filter, wash the precipitated resin with a large amount of deionized water, and vacuum dry at 50°C to obtain 35.3 g of white solid resin sample with a yield of 87%, M w : 12000.

[0099] Example 5

[0100] This example provides a KrF resin with the following structural formula:

[0101]

[0102] The preparation method is as follows:

[0103] Take 25 g (0.15 mol) of 4-acetoxyphenylstyrene, 11.4 g (0.05 mol) of 1-vinylpyrene, 11.8 g (0.05 mol) of 1-cyclohexylcyclopentyl methacrylate, respectively, into a 250 ml three-necked flask under nitrogen, then add 100 ml of tetrahydrofuran to dissolve, and bubble nitrogen to remove oxygen for half an hour under stirring; take 3.28 g (0.014 mol) of azobisdimethyl isobutyrate (AIBME) to dissolve in 10 ml of acetonitrile, then slowly drop the AIBME / acetonitrile solution into the three-necked flask solution, and reflux for 24 hours after dropping.

[0104] Take 23.76 g (0.31 mol) of ammonium acetate, add 6 ml of deionized water, slowly drop the ammonium acetate / water suspension into the post-reaction solution, and stir for 18 hours at room temperature under nitrogen protection.

[0105] After the reaction is completed, the reaction solution is poured into 1 L of deionized water, stirred and precipitated for 2 hours, filtered, and the precipitated resin is washed with a large amount of deionized water and vacuum dried at 50°C to obtain 35 g of a white solid resin sample at a yield of 87%, Mw= 12000, Mn= 6000, and Mw / Mn= 2.0. w :12000.

[0106] The present application also provides a chemically amplified photoresist prepared by the following method:

[0107] 10 g of the KrF resin obtained in Example 1 is weighed, dissolved in 90 ml of ethyl lactate, and 0.5 g of triphenylsulfonium camphorsulfonic acid salt, 0.108 g of TBAL, and 0.024 g of a fluorine-containing surfactant (trade name F563, manufacturer: DIC Corporation, Japan) are added. After stirring and dissolving, filtration is performed through a 0.45 micron filter to obtain a chemically amplified photoresist (photosensitive resin composition) 1.

[0108] The KrF resin obtained in Example 1 used in the above chemically amplified photoresist is replaced with the KrF resin obtained in each of Examples 2 to 5, respectively, and the chemically amplified photoresists 2 to 5 corresponding to Examples 2 to 5 are prepared according to the above method.

[0109] Comparative Example 1

[0110] The present comparative example provides a KrF resin having the following structural formula:

[0111]

[0112] The preparation method thereof is as follows:

[0113] 25 g (0.15 mol) of 4-acetyloxy styrene, 5.2 g (0.05 mol) of styrene, and 6.4 g (0.05 mol) of tert-butyl acrylate are weighed into a 250 ml three-necked flask under a nitrogen atmosphere, and then 100 ml of tetrahydrofuran is added for dissolution, and nitrogen is bubbled for half an hour under stirring to remove oxygen; 3.28 g (0.014 mol) of azobisdimethylisobutyrate (AIBME) is weighed into 10 ml of acetonitrile, and then the AIBME / acetonitrile solution is slowly added dropwise into the three-necked flask solution, and after the dropwise addition is completed, reflux reaction is performed for 24 hours.

[0114] 23.76 g (0.31 mol) of ammonium acetate is weighed, and 6 ml of deionized water is added, and the ammonium acetate / water suspension is slowly added dropwise into the previous reaction solution, and stirring is performed at room temperature under nitrogen protection for 18 hours.

[0115] After the reaction was completed, the reaction solution was poured into 1 L of deionized water and stirred to precipitate for 2 hours, filtered, and the precipitated resin was washed with a large amount of deionized water and dried at 50°C under vacuum to obtain 26.3 g of a white solid resin sample at a yield of 89%, M w : 10000.

[0116] In each of the examples and comparative examples, the structural formula xyz is the molar amount of each monomer used.

[0117] The KrF resin obtained in Example 1 used in Example 6 was replaced with the KrF resin obtained in Comparative Example 1, respectively, and the photoresist 6 of Comparative Example 1 was prepared according to the method of Example 6.

[0118] PEB temperature effect on lithography development test:

[0119] The prepared photoresist was coated on a 4-inch silicon wafer (spin coating speed 2000 rpm), pre-baked at 130°C / 60s to harden the film and remove the solvent, and then exposed under an exposure machine (exposure wavelength 248 nm). After that, it was post-baked at different PEB temperatures (90°C, 110°C), and then developed in 2.38% TMAH developer. After that, the change in film thickness before and after development and the development resolution pattern were tested.

[0120] The results of the PEB temperature effect on lithography performance test are shown in Figure 1 (PEB 90°C) and Figure 2 (PEB 110°C).

[0121] The effect of different activation energy monomers on the edge uniformity of development is shown in Figure 3 .

[0122] As can be seen from Figures 1 to 3 , different activation energy monomers have a great difference in PEB response and edge uniformity of developed patterns. Low activation energy monomers can complete the deprotection process at a lower temperature, thereby normal development, but high activation energy monomers must complete the deprotection process at a higher PEB temperature. At the same time, the edge uniformity of lithography patterns after development is different due to different PEB temperatures, and low activation energy monomer resins are significantly better than high activation energy monomers.

[0123] Ultraviolet absorption test:

[0124] The prepared photoresist was coated on a 2-inch quartz wafer (spin coating speed 2000 rpm), pre-baked at 130°C / 60s to harden the film and remove the solvent, and then tested for ultraviolet absorption in the wavelength range of 190 nm-1100 nm.

[0125] The results of the ultraviolet absorption test are shown in Table 1 below:

[0126] Table 1 Ultraviolet absorption test results

[0127] Resin UV absorption (pm) Example 1 1.7302 Example 2 2.0603 Example 3 2.4356 Example 4 2.3896 Example 5 2.4537 Comparative Example 1 0.1459

[0128] From the data in Table 1, it can be seen that different high absorption monomers have a great influence on the UV absorption of the resin, thus providing a method for better controlling the UV light transmittance in the case of a relatively thin film thickness (THK < 0.5 μm) (if there is no high UV absorption resin, the exposure process will cause problems such as "standing wave undercut" due to the high reflection of light from the bottom of the silicon wafer), and providing a basis for the development of corresponding photoresist products.

[0129] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not limiting; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

[0130] In addition, those skilled in the art can understand that although some embodiments herein include certain features rather than others included in other embodiments, the combination of features of different embodiments means that it is within the scope of the present application and forms different embodiments. For example, in the above claims, any one of the claimed embodiments can be used in any combination. The information disclosed in the BACKGROUND section is only intended to deepen the understanding of the general background of the present application, and should not be regarded as acknowledging or implying in any form that the information constitutes prior art known to those skilled in the art.

Claims

1. A KrF resin, characterized in that Its general structural formula is: ； Among them, R 1 、R 2 、R 3 Each is independently a H atom, a halogen atom, an alkyl group or an alkoxy group having 1 to 6 carbon atoms; R1 is a hydroxyl group, R2 is a high UV absorption group, and R3 is a low activation energy deprotection acidic group; x, y, and z represent the ratios of different monomers in the KrF resin, 0<x<1, 0<y<1, 0<z<1, and x+y+z=1; The high ultraviolet absorption group includes any one of the groups shown in the following structures: 、 、 、 、 、 ； The low activation energy deprotection acidic group includes any one of the groups shown in the following structures: 、 、 、 。 2. The KrF resin according to claim 1, characterized in that The weight average molecular weight of the KrF resin is 1,000-100,000.

3. The KrF resin according to claim 2, characterized in that The weight average molecular weight of the KrF resin is 2,000-50,000.

4. A method for preparing the KrF resin according to any one of claims 1 to 3, characterized in that: include: Mixing raw materials including 4-acetoxystyrene, a first monomer compound, a second monomer compound, and an initiator to perform a first reaction; then adding an ammonium acetate-water suspension to the system to perform a second reaction to obtain the KrF resin; The first monomer compound is a compound comprising a high ultraviolet absorption group, and the second monomer compound is a compound comprising a low activation energy deprotection acidic group; The first monomer compound includes any one of the following compounds: 、 、 、 、 、 ； The second monomer compound includes any one of the following compounds: 、 、 、 。 5. A chemically amplified photoresist, characterized in that: The invention comprises the KrF resin according to claim 1.

6. The chemically amplified photoresist according to claim 5, characterized in that The KrF resin accounts for 5% to 50% of the total mass of the photoresist.

7. The chemically amplified photoresist according to claim 6, wherein The solid content of the photoresist is 5 wt % to 50 wt %.

8. The chemically amplified photoresist according to claim 5, wherein Organic solvents are also included.

9. The chemically amplified photoresist according to claim 8, wherein The organic solvent includes ethers, esters, ketones or hydroxyl-containing solvents.

10. The chemically amplified photoresist according to claim 9, wherein The organic solvent includes at least one of propylene glycol methyl ether acetate, cyclopentanone, cyclohexanone, ethyl lactate, butyl acetate, 2-ethoxyethanol and ethyl 3-ethoxypropionate.

11. The chemically amplified photoresist according to claim 5, wherein Also includes leveling agents.

12. The chemically amplified photoresist according to claim 11, wherein The leveling agent includes a fluorine-containing surfactant and / or a surfactant containing a polyethylene glycol structure.

13. The chemically amplified photoresist according to claim 12, wherein: The leveling agent accounts for 0.001%-1% of the total mass of the photoresist.

14. The chemically amplified photoresist according to claim 5, wherein The photoresist also includes an acid quencher.

15. The chemically amplified photoresist according to claim 14, wherein The acid quencher includes at least one of tetrabutylammonium hydroxide, triisopropanolamine, trog's base, and 1,8-diazabicyclo[5.4.0]undec-7-ene.

16. The chemically amplified photoresist according to claim 15, wherein The acid quencher accounts for 0.001%-2% of the total mass of the photoresist.

17. The chemically amplified photoresist according to any one of claims 5 to 16, characterized in that: Also included are photoacid generators.

18. The chemically amplified photoresist according to claim 17, wherein The photoacid generator includes a sulfonium salt and / or an iodonium salt.

19. The chemically amplified photoresist according to claim 18, wherein The sulfonium salt includes one or more compounds shown in the following structures: 、 、 、 、 。 20. The chemically amplified photoresist according to claim 18, wherein The iodonium salt includes one or more compounds shown in the following structures: 、 、 、 、 。 21. The chemically amplified photoresist according to claim 17, wherein The photoacid generator accounts for 0.05%-10% of the total mass of the photoresist.

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