Negative photoresist composition and application and imaging method thereof

Abstract

The invention relates to the field of microelectronic devices, and provides a negative photoresist composition as well as application and an imaging method thereof. The negative photoresist composition comprises film-forming resin, a cross-linking agent, a photoacid generator, an acid diffusion inhibitor, an additive and a solvent, the additive comprises at least one of compounds shown in the formula I, and R1 and R2 are independently selected from hydrogen or alkyl with the carbon atom number being 1-10. According to the negative photoresist composition, the sensitivity, the resolution ratio and the etching resistance of the photoresist can be remarkably improved. # imgabs0 #

Description

Technical Field

[0001] The invention belongs to the field of microelectronic devices, and in particular provides a negative photoresist composition and an application and imaging method thereof. Background Art

[0002] In the field of microelectronic device manufacturing, photoresist is a key functional material for realizing the transfer of graphics from the mask to the substrate. According to the different chemical reaction mechanisms and development principles, photoresists can be divided into two categories: positive photoresists and negative photoresists. Positive photoresists refer to photoresists in the unexposed areas that are insoluble in the developer, which can protect the underlying substrate material from being affected by the next process, while the photoresist film in the exposed part can be dissolved in the developer to expose the underlying substrate material for easy processing. After the negative photoresist forms a film, the unexposed part can be dissolved in the developer and washed away, while the exposed part becomes insoluble in the developer and remains on the substrate.

[0003] The working principle of negative photoresist is that the photosensitizer in the exposed area generates new substances after exposure to trigger resin polymerization or cross-linking, and the polymerized or cross-linked resin is different from the resin in the unexposed area and becomes insoluble in the developer, thereby leaving a pattern opposite to the mask on the substrate material. Therefore, the components of general negative photoresist include resins containing reactive functional groups, photosensitizers, solvents, and additives. Negative photoresists based on the principle of photochemical amplification also contain photoacid generators (PAGs, also known as photoacid generators). PAGs release acid after exposure, which can catalyze the reaction between the cross-linking agent and the resin to cause cross-linking. Because the exposed part reacts and solidifies, it cannot be dissolved in the developer. It is suitable for making patterns that need to retain the exposed area, especially for making fine structure patterns. Compared with positive photoresist, negative photoresist has a lower cost, but the existing negative photoresist based on the principle of photochemical amplification will expand during the development process. This expansion will cause the edges of the pattern to become blurred, resulting in a relatively low resolution. At the same time, the dissolution rate of the non-exposed area in the negative photoresist needs to be improved to prevent photoresist residue in the non-exposed area after development. Summary of the invention

[0004] In view of the above problems existing in the prior art, the object of the present invention is to provide a negative photoresist composition and its application and imaging method.

[0005] In a first aspect, the present invention provides a negative photoresist composition, comprising: a film-forming resin, a crosslinking agent, a photoacid generator, an acid diffusion inhibitor, an additive and a solvent, wherein the additive comprises at least one of the compounds having a structure as shown in Formula I:

[0006]

[0007] In formula I, R1 and R2 are the same or different and are each independently selected from hydrogen or an alkyl group having 1 to 10 carbon atoms.

[0008] In the negative photoresist composition of the present invention, the introduction of triphenylene containing oxygen substituents (hydroxyl, alkoxy) as an additive can effectively improve the comprehensive performance of the photoresist. Specifically, the triphenylene mother nucleus belongs to a condensed ring aromatic hydrocarbon, which has good etching resistance, but has a low dissolution rate in an alkaline developer, which easily leads to film residue and poor resolution. Substituting triphenylene with a hydroxyl group can increase the dissolution rate of the photoresist in an alkaline developer in a non-exposed area, improve the resolution, and using an alkoxy group to replace triphenylene is conducive to improving the sensitivity of the photoresist. In this way, the additive interacts with components such as a film-forming resin in the composition, which can improve the sensitivity, sensitivity and etching resistance of the photoresist.

[0009] In some embodiments of the present invention, R1 and R2 are each independently selected from hydrogen or an alkyl group having 1 to 8 carbon atoms.

[0010] Furthermore, R1 is hydrogen, and R2 is an alkyl group having 1 to 8 carbon atoms. Thus, the photoresist composition has high resolution, sensitivity and alkali solubility.

[0011] In some embodiments of the present invention, based on the total weight of the negative photoresist composition, the mass content of the film-forming resin is 20% to 30%, the mass content of the cross-linking agent is 10% to 15%, the mass content of the photoacid generator is 1% to 5%, the mass content of the acid diffusion inhibitor is 0.01% to 1%, the mass content of the additive is 1% to 5%, and the mass content of the solvent is 50% to 60%.

[0012] In some embodiments of the present invention, the film-forming resin is a linear phenolic resin.

[0013] In some embodiments of the present invention, the cross-linking agent is selected from at least one of trimethylolpropane triglycidyl ether, tetramethylol glycoluril, tetramethoxymethyl glycoluril, hexamethylol melamine, hexamethoxymethyl melamine and hexamethoxyethyl melamine.

[0014] In some embodiments of the present invention, the photoacid generator is selected from at least one of s-triazine derivatives containing halogenated alkyl groups, halogenated alkanes, halogenated cycloalkanes, benzene derivatives containing halogenated alkyl groups, aryl sulfones containing halogenated alkyl groups, halogenated cycloalkyl sulfones, isocyanurates containing halogenated alkyl groups, and sulfonium salts.

[0015] In some embodiments of the present invention, the acid diffusion inhibitor is selected from at least one of dimethylamine, diethylamine, trimethylamine, triethylamine, tributylamine, diethanolamine, trimethanolamine and triethanolamine.

[0016] In some embodiments of the present invention, the solvent is selected from at least one of propylene glycol methyl ether acetate, propylene glycol methyl ether, diheptanone, methyl isobutyl ketone, ethyl lactate, anisole, cyclopentanone, xylene, ethyl acetate and butyl acetate.

[0017] In some embodiments of the present invention, the negative photoresist composition is prepared by uniformly mixing the film-forming resin, the cross-linking agent, the photoacid generator, the acid diffusion inhibitor, the additive and the solvent and filtering the mixture.

[0018] In a second aspect, the present invention provides use of the negative photoresist composition described in the first aspect of the present invention as a G-line photoresist or an I-line photoresist.

[0019] In a third aspect, the present invention provides an imaging method of the negative photoresist composition described in the first aspect of the present invention, comprising: coating the photoresist composition on a substrate, sequentially performing a first baking, exposure, a second baking and development to obtain a photolithography pattern.

[0020] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. DETAILED DESCRIPTION

[0021] 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.

[0022] The "range" disclosed in the present invention is defined in the form of a lower limit and / or an upper limit, and a given range is defined by selecting a lower limit and / or an upper limit. The range defined in this way can be inclusive or exclusive of the end value, and can be combined arbitrarily, that is, any lower limit can be combined with any upper limit to form an undefined range, and any lower limit can be combined with other lower limits to form an undefined range, and any upper limit can be combined with any other upper limit to form an undefined range. In addition, each separately disclosed point or single value itself can be combined with any other point or single value as a lower limit or upper limit or with other lower limits or upper limits to form an undefined range.

[0023] If not otherwise specified, all embodiments and optional embodiments of the present invention may be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present invention.

[0024] A first aspect of the present invention provides a negative photoresist composition, comprising: a film-forming resin, a cross-linking agent, a photoacid generator, an acid diffusion inhibitor, an additive and a solvent.

[0025] In the present invention, the additive comprises at least one of the compounds having a structure as shown in Formula I:

[0026]

[0027] In formula I, R1 and R2 are the same or different and are each independently selected from hydrogen or an alkyl group having 1 to 10 carbon atoms.

[0028] In the present invention, the alkyl group having 1 to 10 carbon atoms may include a linear alkyl group having 1 to 10 carbon atoms and a branched alkyl group having 3 to 10 carbon atoms. The carbon number of the alkyl group may be 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. Specific examples of the alkyl group include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, cyclopentyl, n-hexyl, heptyl, n-octyl, 2-ethylhexyl, nonyl, decyl, 3,7-dimethyloctyl, and the like.

[0029] In the present invention, in Formula I, each R1 may be the same or different, and each R2 may also be the same or different.

[0030] In some embodiments, R1 and R2 are each independently selected from hydrogen or an alkyl group having 1 to 8 carbon atoms.

[0031] Preferably, R1 is hydrogen, and R2 is an alkyl group having 1 to 8 carbon atoms.

[0032] In some embodiments, the additive is selected from at least one of the following compounds D1 to D8:

[0033]

[0034]

[0035] In the present invention, the compound represented by formula I can be prepared by methods well known in the art, or can be obtained commercially. For example, compounds D1 to D8 can be purchased from Coresyn Pharmatech Co., Ltd., Shenzhen Polymer Biochemical Technology Co., Ltd. and other companies.

[0036] In some embodiments, based on the total weight of the negative photoresist composition, the mass content of the additive is 1% to 5%, for example, 1%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, 3%, 3.1%, 3.5%, 4%, 5%, etc. Thus, while improving the etching resistance, the pattern defects that may be caused by excessive additive content are reduced.

[0037] In the present invention, the film-forming resin can be selected according to the application of the negative photoresist composition. According to some embodiments, the film-forming resin is a linear phenolic resin. The negative photoresist composition under this condition is suitable for use as an I-line photoresist and a G-line photoresist.

[0038] In some embodiments, the weight average molecular weight (Mw) of the linear phenolic resin may be 1000-20000, such as 2000, 3000, 4000, 5000, 6000, 7000, 10000, 15000, 18000, etc. Preferably, the weight average molecular weight of the linear phenolic resin is 3000-6000.

[0039] In the present invention, the molecular weight of the linear phenolic resin can be measured by gel permeation chromatography (GPC).

[0040] In some embodiments, the linear phenolic resin includes a polymerization product formed by a condensation reaction of an alkylphenol monomer and an aldehyde monomer, wherein the alkylphenol monomer is selected from at least one of m-cresol, p-cresol, o-cresol, xylenol and tricresol, and the aldehyde monomer is selected from at least one of formaldehyde, acetaldehyde and propionaldehyde.

[0041] Preferably, the molar ratio of the alkylphenol monomer to the aldehyde monomer is 10:(3-7), for example, 10:3, 10:4, 10:5, 10:5.5, 10:6, 10:7, etc.

[0042] Preferably, the alkylphenol monomers are m-cresol and p-cresol, the aldehyde monomer is formaldehyde, and the molar ratio of m-cresol to p-cresol is 1:(0.8-3), for example, 1:0.8, 1:1, 1:2, 1:2.2, 1:2.5, 1:2.8, 1:3, etc.

[0043] As some examples, the polycondensation reaction can be carried out in the presence of an acid catalyst. The acid catalyst can be, for example, formic acid. The mass amount of the acid catalyst can be 0.5% to 2% of the mass of the alkylphenol monomer, such as 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, etc.

[0044] As some examples, the conditions of the polycondensation reaction may include: a temperature of 80 to 110° C. and a time of 1 to 6 hours.

[0045] In some embodiments, based on the total weight of the negative photoresist composition, the mass content of the film-forming resin is 20% to 30%, for example, 20%, 20.5%, 22%, 25%, 26%, 26.5%, 27%, 27.8%, 28%, 29%, 30%, etc.

[0046] In the present invention, the cross-linking agent can undergo a photochemical curing reaction with the film-forming resin to increase the stability of the photoresist film layer.

[0047] In some embodiments, the cross-linking agent is selected from at least one of trimethylolpropane triglycidyl ether, tetramethylol glycoluril, tetramethoxymethyl glycoluril, hexamethylol melamine, hexamethoxymethyl melamine and hexamethoxyethyl melamine.

[0048] In some embodiments, based on the total weight of the negative photoresist composition, the mass content of the crosslinker is 10% to 15%, for example, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 14%, 15%, etc.

[0049] In the present invention, the negative photoresist composition belongs to a chemically amplified photoresist. The photoacid generator (PAG) is a photosensitive compound and can be selected from existing chemically amplified photoresists. During the post-exposure baking process, the photoacid generator can decompose to generate acid, which can catalyze the crosslinking agent to react with the resin to crosslink, and the exposed part reacts and solidifies, so that the photoresist in the exposed area cannot be dissolved in the alkaline developer.

[0050] In some embodiments, the photoacid generator may be selected from at least one of s-triazine derivatives containing halogenated alkyl groups, halogenated alkanes, halogenated cycloalkanes, benzene derivatives containing halogenated alkyl groups, aryl sulfones containing halogenated alkyl groups, halogenated cycloalkyl sulfones, isocyanurates containing halogenated alkyl groups, and sulfonium salts.

[0051] As some preferred examples, the halogenated alkyl-containing s-triazine derivative is selected from at least one of tris(trichloromethyl)s-triazine, tris(tribromomethyl)s-triazine, tris(dibromomethyl)s-triazine, 2,4-bis(tribromomethyl)-6-p-methoxyphenyl-s-triazine and 2-[2-(5-methylfuran-2-yl)vinyl]-4,6-bis(trichloromethyl)s-triazine.

[0052] As some preferred examples, the halogenated alkane is selected from at least one of 1,2,3,4-tetrabromobutane, 1,1,2,2-tetrabromoethane, carbon tetrabromide and iodoform.

[0053] As some preferred examples, the halogenated cycloalkane is at least one selected from hexabromocyclohexane, hexachlorocyclohexane and hexabromocyclododecane.

[0054] As some preferred examples, the benzene derivative containing a halogenated alkyl group is selected from at least one of bis(trichloromethyl)benzene and bis(tribromomethyl)benzene.

[0055] As some preferred examples, the aryl sulfone containing the halogenated alkyl group is selected from at least one of tribromomethyl phenyl sulfone and trichloromethyl phenyl sulfone.

[0056] As some preferred examples, the halogenated cycloalkyl sulfone is 2,3-dibromocyclopentane.

[0057] As some preferred examples, the alkyl halide-containing isocyanurate is tris(2,3-dibromopropyl)isocyanurate.

[0058] As some preferred examples, the sulfonium salt is selected from at least one of triphenylsulfonium chloride, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium p-toluenesulfonate, triphenylsulfonium tetrafluoroborate, triphenylsulfonium hexafluoroarsenate and triphenylsulfonium hexafluorophosphate.

[0059] In some embodiments, based on the total weight of the negative photoresist composition, the mass content of the photoacid generator is 1% to 5%, for example, 1%, 1.5%, 1.8%, 2%, 2.1%, 2.5%, 3%, 3.1%, 3.3%, 3.5%, 3.8%, 4%, 4.3%, 4.5%, 4.7%, 5%, etc.

[0060] In the present invention, the acid diffusion inhibitor can control the diffusion capacity of the photoacid generator to improve the resolution and reduce the line width roughness. The acid diffusion inhibitor can be selected from various basic compounds. As some embodiments, the acid diffusion inhibitor is selected from at least one of dimethylamine, diethylamine, trimethylamine, triethylamine, tributylamine, diethanolamine, trimethanolamine and triethanolamine.

[0061] In some embodiments, based on the total weight of the negative photoresist composition, the mass content of the acid diffusion inhibitor is 0.01% to 1%, for example, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.07%, 0.1%, 0.2%, 0.25%, 0.28%, 0.3%, 0.33%, 0.36%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, etc.

[0062] In the present invention, the solvent may be an organic solvent, for example, may be selected from ketones, alcohol ethers, and ester solvents. In some embodiments, the solvent is selected from at least one of propylene glycol methyl ether acetate (PGMEA), propylene glycol methyl ether (PGME), diheptanone, methyl isobutyl ketone, ethyl lactate, anisole, cyclopentanone, xylene, ethyl acetate, and butyl acetate.

[0063] In some embodiments, based on the total weight of the negative photoresist composition, the mass of the solvent may be 50% to 60%, for example, 50%, 55%, 56%, 59%, 60%, etc.

[0064] In some embodiments, the negative photoresist composition can be prepared by uniformly mixing the film-forming resin, the cross-linking agent, the photoacid generator, the acid diffusion inhibitor, the additive and the solvent and filtering the mixture.

[0065] According to a more specific embodiment, the negative photoresist composition can be prepared by a method comprising the following steps: adding a film-forming resin, a cross-linking agent, a photoacid generator, an acid diffusion inhibitor, an additive and a solvent into a light-proof container, shaking in a light-proof container for 24 to 48 hours to completely dissolve each component to obtain a photoresist solution; and then filtering with a filter of 0.5 μm or less to obtain a photoresist composition.

[0066] The second aspect of the present invention provides use of the negative photoresist composition as a G-line photoresist or an I-line photoresist.

[0067] In some embodiments, the negative photoresist composition is a G-line photoresist, and the wavelength of the light source during exposure of the G-line photoresist is 436 nm.

[0068] In other embodiments, the negative photoresist composition is an I-line photoresist, and the wavelength of the light source during exposure of the I-line photoresist is 365 nm.

[0069] The third aspect of the present invention provides an imaging method of the negative photoresist composition, which comprises: coating the photoresist composition on a substrate, and sequentially performing a first baking, exposure, a second baking and development to obtain a photolithographic pattern.

[0070] In the present invention, the first baking and the second baking can be performed at temperatures of 80 to 130° C. and for a time of 30 to 120 seconds, respectively.

[0071] In the present invention, the wavelength of the light source for exposure may be 436 nm or 365 nm.

[0072] In the present invention, the developer used in the development may be a tetramethylammonium hydroxide (TMAH) solution with a concentration of 2.38 wt %.

[0073] The following are examples of the present invention. The following examples are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0074] Synthesis example 1

[0075] This synthesis example is used to illustrate the preparation method of the linear phenolic resin used in the following examples and comparative examples, wherein parts refer to parts by weight.

[0076] Add 162 parts of m-cresol and 162 parts of p-cresol to the reactor, raise the temperature to 90°C and start stirring. During the stirring process, add 3.24 parts of oxalic acid, and then add 150 parts of 37wt% formaldehyde aqueous solution dropwise for 30 minutes. After the addition is completed, react at 90-100°C for 4h. The obtained product is washed with water and vacuum dried to obtain a linear phenolic resin. GPC test shows that the resin has a Mw of 6000.

[0077] Example 1

[0078] 23 g of linear phenolic resin, 2 g of compound D1, 10 g of tetramethoxymethyl glycoluril, 3 g of triphenylsulfonium p-toluenesulfonate, 0.05 g of triethanolamine and 50 g of propylene glycol methyl ether acetate were added to a light-proof glass container, shaken in the dark for 30 hours to completely dissolve the components, and then filtered through a filter element with a pore size of 0.2 μm to obtain a photoresist composition, recorded as PR-1.

[0079] Example 2

[0080] 25 g of linear phenolic resin, 2 g of compound D2, 10 g of tetramethoxymethyl glycoluril, 3 g of triphenylsulfonium toluenesulfonate, 0.03 g of triethanolamine and 50 g of propylene glycol methyl ether acetate were added to a light-proof glass container, shaken in the dark for 30 hours to completely dissolve the components, and then filtered through a filter element with a pore size of 0.2 μm to obtain a photoresist composition, recorded as PR-2.

[0081] Example 3

[0082] 25 g of linear phenolic resin, 2 g of compound D3, 10 g of tetramethoxymethyl glycoluril, 3 g of triphenylsulfonium p-toluenesulfonate, 0.03 g of triethanolamine and 50 g of propylene glycol methyl ether acetate were added to a light-proof glass container, shaken in the dark for 30 hours to completely dissolve the components, and then filtered through a filter element with a pore size of 0.2 μm to obtain a photoresist composition, recorded as PR-3.

[0083] Example 4

[0084] 22 g of linear phenolic resin, 1.5 g of compound D4, 9 g of tetramethoxymethyl glycoluril, 2.5 g of triphenylsulfonium toluenesulfonate, 0.05 g of triethanolamine and 48 g of propylene glycol methyl ether acetate were added to a light-proof glass container, shaken in the dark for 30 hours to completely dissolve the components, and then filtered through a filter element with a pore size of 0.2 μm to obtain a photoresist composition, recorded as PR-4.

[0085] Example 5

[0086] 25 g of linear phenolic resin, 2 g of compound D5, 10 g of tetramethoxymethyl glycoluril, 3 g of triphenylsulfonium p-toluenesulfonate, 0.05 g of triethanolamine and 50 g of propylene glycol methyl ether acetate were added to a light-proof glass container, shaken in the dark for 30 hours to completely dissolve the components, and then filtered through a filter element with a pore size of 0.2 μm to obtain a photoresist composition, recorded as PR-5.

[0087] Example 6

[0088] 25 g of linear phenolic resin, 2 g of compound D6, 10 g of tetramethoxymethyl glycoluril, 3 g of triphenylsulfonium toluenesulfonate, 0.05 g of triethanolamine and 50 g of propylene glycol methyl ether acetate were added to a light-proof glass container, shaken in the dark for 30 hours to completely dissolve the components, and then filtered through a filter element with a pore size of 0.2 μm to obtain a photoresist composition, recorded as PR-6.

[0089] Example 7

[0090] 25 g of linear phenolic resin, 4.2 g of compound D7, 10 g of tetramethoxymethyl glycoluril, 2 g of triphenylsulfonium toluenesulfonate, 0.01 g of triethanolamine and 45 g of propylene glycol methyl ether acetate were added to a light-proof glass container, shaken in the dark for 30 hours to completely dissolve the components, and then filtered through a filter element with a pore size of 0.2 μm to obtain a photoresist composition, recorded as PR-7.

[0091] Example 8

[0092] 23 g of linear phenolic resin, 2 g of compound D8, 10 g of tetramethoxymethyl glycoluril, 2 g of triphenylsulfonium p-toluenesulfonate, 0.01 g of triethanolamine and 50 g of propylene glycol methyl ether acetate were added to a light-proof glass container, shaken in the dark for 30 hours to completely dissolve the components, and then filtered through a filter element with a pore size of 0.2 μm to obtain a photoresist composition, recorded as PR-8.

[0093] Example 9

[0094] 25 g of linear phenolic resin, 2 g of compound D3, 10 g of trimethylolpropane triglycidyl ether, 3 g of triphenylsulfonium chloride, 0.03 g of diethylamine and 50 g of propylene glycol methyl ether acetate were added to a light-proof glass container, shaken in the dark for 30 hours to completely dissolve the components, and then filtered through a filter element with a pore size of 0.2 μm to obtain a photoresist composition, recorded as PR-9.

[0095] Comparative Example 1

[0096] 25 g of linear phenolic resin, 10 g of tetramethoxymethyl glycoluril, 3 g of triphenylsulfonium toluenesulfonate, 0.03 g of triethanolamine and 50 g of propylene glycol methyl ether acetate were added to a light-proof glass container, shaken in the dark for 30 hours to completely dissolve the components, and then filtered using a filter element with a pore size of 0.2 μm to obtain a photoresist composition, recorded as PR-D1.

[0097] Comparative Example 2

[0098] 25 g of linear phenolic resin, 2 g of triphenylene, 10 g of tetramethoxymethyl glycoluril, 3 g of triphenylsulfonium toluenesulfonate, 0.03 g of triethanolamine and 50 g of propylene glycol methyl ether acetate were added to a light-proof glass container, shaken in the dark for 30 hours to completely dissolve the components, and then filtered through a 0.2 μm filter element to obtain a photoresist composition, recorded as PR-D2.

[0099] Test Case

[0100] The test examples are used to illustrate the application performance of the photoresist compositions PR-1 to PR-9 and PR-D1 and PR-D2 prepared in the above embodiments and comparative examples.

[0101] 1. Sensitivity test

[0102] A coating machine was used to coat glue on a 2-inch silicon wafer, and the rotation speed of spin coating was adjusted according to the thickness of the photoresist layer. After the spin coating was completed, a hardening baking (100°C, 60s) was performed, and the film thickness was measured after cooling to form a 0.5μm photoresist layer; a 365nm light source was used for exposure, and a light shield with a 1cm diameter circular hole was used to expose the photoresist layer at different doses; then the photoresist layer was developed with a 2.38wt% tetramethylammonium hydroxide aqueous solution for 60s; the residual thickness of the photoresist film layer after development was measured at different exposure doses, and the dose corresponding to the pattern with zero thickness of the photoresist film layer was the sensitivity of the photoresist.

[0103] 2. Resolution test

[0104] Use a coating machine to coat glue on a 2-inch silicon wafer, adjust the spin coating speed according to the thickness of the photoresist layer, and after the spin coating is completed, perform film hardening baking (100°C, 60s), measure the film thickness after cooling, and form a 0.5μm photoresist layer; use a 365nm light source for exposure, and the mask is set with a line width of 3 to 0.35μm, and the ratio of line width to grating spacing is 1:1. Then, use 2.38wt% tetramethylammonium hydroxide aqueous solution for development, and determine the minimum line width that can be clearly observed after development.

[0105] 3. Etching resistance test

[0106] Place the silicon wafer with photoresist spin-coated in a LAM RESEARCH etcher and etch for 30 seconds at 40CF4 / 240Ar / 60O2 (the numbers before the gases represent their respective flow rates in mL / min). Calculate the etching rate based on the film thickness before and after etching and the etching time. The lower the etching rate, the better the etching resistance.

[0107] 4. Test of alkali dissolution rate

[0108] The photoresist was exposed and then developed in a 2.38wt% tetramethylammonium hydroxide aqueous solution for 10s. The film thickness before and after development was measured. The dissolution rate (ADR) = film thickness difference before and after development / development time

[0109] The test results are shown in Table 1.

[0110] Table 1

[0111]

[0112] Combined with the results shown in Table 1, by comparing Examples 1 to 9 with Comparative Examples 1 to 2, it can be seen that the use of the compound shown in Formula I as an additive in the photoresist composition can significantly improve the sensitivity and resolution of the negative chemically amplified photoresist, so that the photoresist composition exhibits better etching resistance and higher alkali dissolution rate.

[0113] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; 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 invention, and they should all be included in the scope of the claims and specification of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any way. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A negative photoresist composition, characterized in that include: A film-forming resin, a cross-linking agent, a photoacid generator, an acid diffusion inhibitor, an additive and a solvent, wherein the additive comprises at least one of the compounds having a structure as shown in Formula I: In formula I, R1 and R2 are the same or different and are each independently selected from hydrogen or an alkyl group having 1 to 10 carbon atoms.

2. The negative photoresist composition according to claim 1, characterized in that R1 and R2 are each independently selected from hydrogen or an alkyl group having 1 to 8 carbon atoms; Preferably, R1 is hydrogen, and R2 is an alkyl group having 1 to 8 carbon atoms; Preferably, the additive is selected from at least one of the following compounds D1 to D8:

3. The negative photoresist composition according to claim 1 or 2, characterized in that: Based on the total weight of the negative photoresist composition, the mass content of the film-forming resin is 20% to 30%, the mass content of the cross-linking agent is 10% to 15%, the mass content of the photoacid generator is 1% to 5%, the mass content of the acid diffusion inhibitor is 0.01% to 1%, the mass content of the additive is 1% to 5%, and the mass content of the solvent is 50% to 60%.

4. The negative photoresist composition according to any one of claims 1 to 3, characterized in that: The film-forming resin is a linear phenolic resin; Preferably, the weight average molecular weight of the linear phenolic resin is 1000 to 20000, more preferably 3000 to 6000; Preferably, the linear phenolic resin comprises a polymer product formed by a polycondensation reaction of an alkylphenol monomer and an aldehyde monomer, wherein the alkylphenol monomer is selected from at least one of m-cresol, p-cresol, o-cresol, xylenol and tricresol, and the aldehyde monomer is selected from at least one of formaldehyde, acetaldehyde and propionaldehyde; Preferably, the molar ratio of the alkylphenol monomer to the aldehyde monomer is 10:(3-7); Preferably, the alkylphenol monomers are m-cresol and p-cresol, the aldehyde monomer is formaldehyde, and the molar ratio of m-cresol to p-cresol is 1:(0.8-3).

5. The negative photoresist composition according to any one of claims 1 to 4, characterized in that: The cross-linking agent is selected from at least one of trimethylolpropane triglycidyl ether, tetramethylol glycoluril, tetramethoxymethyl glycoluril, hexamethylol melamine, hexamethoxymethyl melamine and hexamethoxyethyl melamine.

6. The negative photoresist composition according to any one of claims 1 to 5, characterized in that: The photoacid generator is selected from at least one of s-triazine derivatives containing halogenated alkyl groups, halogenated alkanes, halogenated cycloalkanes, benzene derivatives containing halogenated alkyl groups, aryl sulfones containing halogenated alkyl groups, halogenated cycloalkyl sulfones, isocyanurates containing halogenated alkyl groups, and sulfonium salts; Preferably, the halogenated alkyl-containing s-triazine derivative is selected from at least one of tris(trichloromethyl)-s-triazine, tris(tribromomethyl)-s-triazine, tris(dibromomethyl)-s-triazine, 2,4-bis(tribromomethyl)-6-p-methoxyphenyl-s-triazine and 2-[2-(5-methylfuran-2-yl)vinyl]-4,6-bis(trichloromethyl)-s-triazine; Preferably, the halogenated alkane is selected from at least one of 1,2,3,4-tetrabromobutane, 1,1,2,2-tetrabromoethane, carbon tetrabromide and iodoform; Preferably, the halogenated cycloalkane is selected from at least one of hexabromocyclohexane, hexachlorocyclohexane and hexabromocyclododecane; Preferably, the benzene derivative containing a halogenated alkyl group is selected from bis(trichloromethyl)benzene and / or bis(tribromomethyl)benzene; Preferably, the aryl sulfone of the halogenated alkyl group is selected from tribromomethyl phenyl sulfone and / or trichloromethyl phenyl sulfone; Preferably, the halogenated cycloalkyl sulfone is 2,3-dibromocyclopentane; Preferably, the alkyl halide-containing isocyanurate is tris(2,3-dibromopropyl)isocyanurate; Preferably, the sulfonium salt is selected from at least one of triphenylsulfonium chloride, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium p-toluenesulfonate, triphenylsulfonium tetrafluoroborate, triphenylsulfonium hexafluoroarsenate and triphenylsulfonium hexafluorophosphate.

7. The negative photoresist composition according to any one of claims 1 to 6, characterized in that: The acid diffusion inhibitor is selected from at least one of dimethylamine, diethylamine, trimethylamine, triethylamine, tributylamine, diethanolamine, trimethanolamine and triethanolamine.

8. The negative photoresist composition according to any one of claims 1 to 7, characterized in that: The solvent is selected from at least one of propylene glycol methyl ether acetate, propylene glycol methyl ether, diheptanone, methyl isobutyl ketone, ethyl lactate, anisole, cyclopentanone, xylene, ethyl acetate and butyl acetate; Preferably, the negative photoresist composition is prepared by uniformly mixing the film-forming resin, the cross-linking agent, the photoacid generator, the acid diffusion inhibitor, the additive and the solvent and filtering the mixture.

9. Use of the negative photoresist composition according to any one of claims 1 to 8 as a G-line photoresist or an I-line photoresist.

10. The imaging method of the negative photoresist composition according to any one of claims 1 to 8, characterized in that: include: The photoresist composition is coated on a substrate, and sequentially subjected to first baking, exposure, second baking and development to obtain a photolithographic pattern; Preferably, the wavelength of the light source for exposure is 436 nm or 365 nm.

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