A composition for forming a bottom spin-coated carbon coating and a bottom spin-coated carbon coating

Abstract

The present invention provides a composition for forming a bottom spin-coated carbon coating and a bottom spin-coated carbon coating. The composition for forming a bottom spin-coated carbon coating comprises a polymer, and the polymer is a polymer formed by the polymerization reaction of a compound represented by formula A with an aromatic aldehyde or an aromatic ketone: #imgabs0# In formula A, R1 are the same or different and are independently selected from a hydroxyl group, an alkoxy group, an alkyl group, an alkenyl group, -CH(O-alkyl)-O-alkyl, -C(=O)-alkyl or a glycidyl group; R2 are the same or different and are independently selected from a hydrogen atom, an alkyl group, an alkenyl group or an aryl group; k are the same or different and are independently 0 or 1, and at least one hydroxyl group is contained on the four phenyl groups attached with -(R1) k and -OR2 located at the periphery of the compound represented by formula A. The bottom spin-coated carbon coating has high thermal stability, good etching resistance to a fluorocarbon etching gas and excellent filling performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithography processes, and particularly relates to a composition for forming a bottom anti-reflective coating and a bottom anti-reflective coating. The composition has good etching resistance, high thermal stability, and excellent filling performance. Background Art

[0002] Lithography is a key step in semiconductor chip manufacturing, accounting for more than 30% of the chip manufacturing cost. Lithography technology represents the development level of the entire semiconductor industry. With the development of lithography technology, the semiconductor process nodes are getting smaller and the device integration is getting higher, which also puts forward higher requirements for lithography technology and lithography materials. In order to better meet the requirements, a three-layer lithography process that provides an anti-reflective coating and a bottom anti-reflective coating between the substrate and the photoresist layer can achieve further reduction of pattern size and higher integration.

[0003] The three-layer lithography process usually uses three photo-functional materials, namely a photoresist coating, an anti-reflective coating, and a bottom anti-reflective coating, to achieve the transfer of high-resolution patterns from the mask to the silicon wafer substrate. The three-layer lithography process is to spin-coat the bottom anti-reflective coating composition, the anti-reflective coating composition, and the photoresist composition onto the substrate in sequence, and then perform a three-layer etching process by utilizing the differences in the etching selectivity of the photoresist coating, the anti-reflective coating, and the bottom anti-reflective coating for fluorine-containing gases and oxygen-containing plasma gases. The specific steps of this three-layer lithography process are as follows: 1) Spin-coat the bottom anti-reflective coating composition, the anti-reflective coating composition, and the photoresist composition onto the silicon wafer substrate in sequence; 2) Expose the predetermined area (defined by the mask) of the photoresist coating, and develop it to form a patterned photoresist coating; 3) Using the patterned photoresist coating as a mask, etch through gases such as CF4 / CHF3 to transfer the pattern from the photoresist coating to the anti-reflective coating; 4) Using the anti-reflective coating as a mask, etch through O2 plasma gas to transfer the pattern from the anti-reflective coating to the bottom anti-reflective coating; 5) Using the bottom anti-reflective coating as a mask, etch through gases such as CF4 / CHF3 to transfer the pattern from the bottom anti-reflective coating to the surface of the silicon wafer substrate. Through the above process, the purpose of transferring the pattern from the mask to the substrate surface is achieved. Summary of the Invention

[0004] It has been found through research that when a material with a high carbon content is used for the bottom anti-reflective coating in direct contact with the substrate, the etching selectivity during substrate processing is high, and the pattern can be transferred more precisely. However, when reducing the size of the etched pattern, the bottom anti-reflective coating may be over-etched. This requires the bottom anti-reflective coating to have high pattern transfer ability and etching resistance. In order to improve the accuracy of the bottom anti-reflective coating when transferring fine patterns as a photomask, the bottom anti-reflective coating is also required to have excellent filling performance.

[0005] In view of this, the present invention provides a polymer and a preparation method thereof. The polymer is used for forming a composition of a bottom spin-coated carbon coating, and a bottom spin-coated carbon coating prepared therefrom. The bottom spin-coated carbon coating has high thermal stability, good etching resistance to fluorocarbon etching gas and excellent filling performance.

[0006] The present invention is achieved by the following technical solutions:

[0007] A polymer, which is a polymer formed by the polymerization reaction of a compound represented by formula A with an aromatic aldehyde or an aromatic ketone:

[0008]

[0009] In formula A, R1 are the same or different, and are independently selected from a hydroxyl group, an alkoxy group, an alkyl group, an alkenyl group, -CH(O-alkyl)-O-alkyl, -C(=O)-alkyl or a glycidyl group; R2 are the same or different, and are independently selected from a hydrogen atom, an alkyl group, an alkenyl group or an aryl group; k are the same or different, and are independently 0 or 1, and at least one hydroxyl group is contained on the four phenyl groups connected with -(R1) k and -OR2 located on the periphery of the compound represented by formula A.

[0010] The present invention also provides a composition for forming a bottom spin-coated carbon coating, and the composition includes the above polymer.

[0011] The present invention also provides a bottom spin-coated carbon coating, and the bottom spin-coated carbon coating is prepared by the above composition for forming a bottom spin-coated carbon coating.

[0012] Advantages of the present invention:

[0013] The present invention provides a composition for forming a bottom spin-coated carbon coating and a bottom spin-coated carbon coating. When used as a mask material for a photoresist, the bottom spin-coated carbon coating has good etching resistance, high thermal stability and excellent filling performance.

[0014] Term Definition

[0015] The term "alkyl" should be understood to preferably represent a straight-chain or branched-chain saturated hydrocarbon group having 1 to 12 carbon atoms, preferably C 1-10 alkyl. "C 1-10"Alkyl" should preferably be understood to represent a straight-chain or branched-chain saturated hydrocarbon group having 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 carbon atoms. The alkyl group is, for example, methyl, ethyl, propyl, butyl, pentyl, hexyl, isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, 2-methylbutyl, 1-methylbutyl, 1-ethylpropyl, 1,2-dimethylpropyl, neopentyl, 1,1-dimethylpropyl, 4-methylpentyl, 3-methylpentyl, 2-methylpentyl, 1-methylpentyl, 2-ethylbutyl, 1-ethylbutyl, 3,3-dimethylbutyl, 2,2-dimethylbutyl, 1,1-dimethylbutyl, 2,3-dimethylbutyl, 1,3-dimethylbutyl or 1,2-dimethylbutyl, etc. or their isomers. In particular, the group has 1, 2, 3, 4, 5, 6 carbon atoms ("C 1-6 alkyl"), such as methyl, ethyl, propyl, butyl, isopropyl, isobutyl, sec-butyl, tert-butyl, and more particularly, the group has 1, 2 or 3 carbon atoms ("C 1-3 alkyl"), such as methyl, ethyl, n-propyl or isopropyl.

[0016] The term "alkenyl" should preferably be understood to represent a straight-chain or branched-chain hydrocarbon group which contains one or more double bonds and has 2 to 12 carbon atoms, preferably "C 2-10 alkenyl". "C 2-10 alkenyl" should preferably be understood to represent a straight-chain or branched-chain hydrocarbon group which contains one or more double bonds and has 2, 3, 4, 5, 6, 7, 8, 9 or 10 carbon atoms, especially 2 or 3 carbon atoms ("C 2-3"Alkenyl"), it should be understood that in the case where the alkenyl contains more than one double bond, the double bonds may be separated from each other or conjugated. The alkenyl is, for example, vinyl, allyl, (E)-2-methylvinyl, (Z)-2-methylvinyl, (E)-but-2-enyl, (Z)-but-2-enyl, (E)-but-1-enyl, (Z)-but-1-enyl, pent-4-enyl, (E)-pent-3-enyl, (Z)-pent-3-enyl, (E)-pent-2-enyl, (Z)-pent-2-enyl, (E)-pent-1-enyl, (Z)-pent-1-enyl, hex-5-enyl, (E)-hex-4-enyl, (Z)-hex-4-enyl, (E)-hex-3-enyl, (Z)-hex-3-enyl, (E)-hex-2-enyl, (Z)-hex-2-enyl, (E)-hex-1-enyl, (Z)-hex-1-enyl, isopropenyl, 2-methylprop-2-enyl, 1-methylprop-2-enyl, 2-methylprop-1-enyl, (E)-1-methylprop-1-enyl, (Z)-1-methylprop-1-enyl, 3-methylbut-3-enyl, 2-methylbut-3-enyl, 1-methylbut-3-enyl, 3-methylbut-2-enyl, (E)-2-methylbut-2-enyl, (Z)-2-methylbut-2-enyl, (E)-1-methylbut-2-enyl, (Z)-1-methylbut-2-enyl, (E)-3-methylbut-1-enyl, (Z)-3-methylbut-1-enyl, (E)-2-methylbut-1-enyl, (Z)-2-methylbut-1-enyl, (E)-1-methylbut-1-enyl, (Z)-1-methylbut-1-enyl, 1,1-dimethylprop-2-enyl, 1-ethylprop-1-enyl, 1-propylvinyl, 1-isopropylvinyl.

[0017] The term "aryl" should be understood to preferably denote a monocyclic, bicyclic or tricyclic hydrocarbon ring that is aromatic or partially aromatic and has 6 to 20 carbon atoms, preferably "C 6-14 aryl". The term "C 6-14 aryl" should be understood to preferably denote a monocyclic, bicyclic or tricyclic hydrocarbon ring that is aromatic or partially aromatic and has 6, 7, 8, 9, 10, 11, 12, 13 or 14 carbon atoms ("C 6-14 aryl"), especially a ring having 6 carbon atoms ("C6 aryl"), such as phenyl; or biphenyl, or a ring having 9 carbon atoms ("C9 aryl"), such as indanyl or indenyl, or a ring having 10 carbon atoms ("C 10 aryl"), such as tetrahydronaphthyl, dihydronaphthyl or naphthyl, or a ring having 13 carbon atoms ("C 13 aryl"), such as fluorenyl, or a ring having 14 carbon atoms ("C 14 aryl"), such as anthryl.

[0018] The term "glycidyl" has the structural formula as described below:

[0019] Description of the Drawings

[0020] Figure 1 Scanning electron micrograph of a silicon wafer substrate formed after spin - coating a composition for forming a bottom - spin - coated carbon coating in Example 3.

[0021] Figure 2 Scanning electron micrograph of a silicon wafer substrate formed after spin - coating a composition for forming a bottom - spin - coated carbon coating in Comparative Example 1.

[0022] Figure 3 Schematic diagram of a photolithography three - layer structure process. Detailed Description of the Invention

[0023] <Polymer>

[0024] As described above, the present invention provides a polymer which is a polymer formed by the polymerization reaction of a compound represented by formula A with an aromatic aldehyde or an aromatic ketone:

[0025]

[0026] In formula A, R1 are the same or different and are independently selected from a hydroxyl group, an alkoxy group, an alkyl group, an alkenyl group, -CH(O - alkyl)-O - alkyl, -C(=O)-alkyl or a glycidyl group; R2 are the same or different and are independently selected from a hydrogen atom, an alkyl group, an alkenyl group or an aryl group; k are the same or different and are independently 0 or 1, and at least one hydroxyl group is contained on the four phenyl groups attached with -(R1) k and -OR2 on the periphery of the compound represented by formula A.

[0027] According to an embodiment of the present invention, in formula A, R1 are the same or different and are independently selected from a hydroxyl group, C 1-12 alkoxy group, C 1-12 alkyl group, C 2-12 alkenyl group, -CH(O - C 1-12 alkyl)-O - C 1-12 alkyl, -C(=O)-C 1-12 alkyl or a glycidyl group; R2 are the same or different and are independently selected from a hydrogen atom, C 1-12 alkyl group, C 2-12 alkenyl group or C 6-20 aryl group; k are the same or different and are independently 0 or 1, and at least one hydroxyl group is contained on the four phenyl groups attached with -(R1) k and -OR2 on the periphery of the compound represented by formula A.

[0028] According to an embodiment of the present invention, in formula A, R1 are the same or different and are independently selected from hydroxy, C 1-6 alkoxy, C 1-6 alkyl, C 2-6 alkenyl, -CH(O-C 1-6 alkyl)-O-C 1-6 alkyl, -C(=O)-C 1-6 alkyl or glycidyl; R2 are the same or different and are independently selected from a hydrogen atom, C 1-6 alkyl, C 2-6 alkenyl or C 6-12 aryl; k are the same or different and are independently 0 or 1, and at least one hydroxy group is contained on each of the four phenyl groups connected with -(R1) k and -OR2 on the periphery of the compound represented by formula A.

[0029] According to an embodiment of the present invention, in formula A, all R2 are H.

[0030] According to an embodiment of the present invention, in formula A, at least two hydroxy groups are contained on each of the four phenyl groups connected with -(R1) k and -OR2 on the periphery of the compound represented by formula A.

[0031] Preferably, in formula A, at least three hydroxy groups are contained on each of the four phenyl groups connected with -(R1) k and -OR2 on the periphery of the compound represented by formula A.

[0032] More preferably, in formula A, at least four hydroxy groups are contained on each of the four phenyl groups connected with -(R1) k and -OR2 on the periphery of the compound represented by formula A.

[0033] According to an embodiment of the present invention, in formula A, at least two of the four phenyl groups connected with -(R1) k and -OR2 on the periphery of the compound represented by formula A each have at least one hydroxy group.

[0034] Preferably, in formula A, each of the four phenyl groups connected with -(R1) k and -OR2 on the periphery of the compound represented by formula A has at least one hydroxy group.

[0035] According to an embodiment of the present invention, the compound represented by formula A has the following structure:

[0036]

[0037] According to an embodiment of the present invention, the aromatic aldehyde is an aldehyde containing an aromatic group. The structural formula of the aromatic aldehyde is, for example, R-CHO, where R is an aryl group, heteroaryl group, arylalkyl group, or heteroarylalkyl group that is unsubstituted or optionally substituted with 1-3 Ra groups, and the substituents are, for example, alkyl groups, alkoxy groups, hydroxyl groups, amino groups, -NH(alkyl), -N(alkyl)2, -OCO-alkyl, -CO-alkyl, etc. In some embodiments, R is a substituted or unsubstituted C 6-20 aryl group, such as a phenyl group, naphthyl group, anthracenyl group, or pyrenyl group.

[0038] According to an embodiment of the present invention, the aromatic aldehyde includes, for example, at least one of furfural, benzaldehyde, naphthaldehyde, anthracenealdehyde, phenanthrenealdehyde, pyrenealdehyde, salicylaldehyde, phenylacetaldehyde, 3-phenylpropanal, tolylaldehyde, (N,N-dimethylamino)benzaldehyde, acetoxybenzaldehyde, 1-pyran carboxaldehyde, and anisaldehyde; preferably at least one of benzaldehyde, anthracenealdehyde, and pyrenealdehyde.

[0039] According to an embodiment of the present invention, the aromatic ketone is a ketone containing an aromatic group. The structural formula of the aromatic ketone is, for example, R-CO-R', where R and R' are the same or different and are independently an aryl group, heteroaryl group, arylalkyl group, or heteroarylalkyl group that is unsubstituted or optionally substituted with 1-3 Ra groups, and the substituents are, for example, alkyl groups, alkoxy groups, hydroxyl groups, amino groups, -NH(alkyl), -N(alkyl)2, -OCO-alkyl, -CO-alkyl, etc.

[0040] According to an embodiment of the present invention, the aromatic ketone includes diaryl ketones, such as at least one of diphenyl ketone, phenylnaphthyl ketone, dinaphthyl ketone, phenyltolyl ketone, xylenyl ketone, and 9-fluorenone.

[0041] According to an embodiment of the present invention, the temperature of the polymerization reaction is 100-150°C; the time of the polymerization reaction is 12-36 hours.

[0042] According to an embodiment of the present invention, the polymerization reaction is carried out under acidic conditions or under alkaline conditions.

[0043] According to an embodiment of the present invention, the polymer is a polymer formed by a polymerization reaction of a compound represented by formula A, an aromatic aldehyde or aromatic ketone, and other aldehydes (such as alkyl aldehydes, such as formaldehyde, acetaldehyde, propionaldehyde, etc.).

[0044] According to an embodiment of the present invention, a polymerization reaction (such as a condensation reaction) occurs between the ortho or para position of the phenolic hydroxyl group in the compound represented by formula A and the aromatic aldehyde or aromatic ketone to form the polymer.

[0045] According to an embodiment of the present invention, the phenolic hydroxyl group at the ortho- or para-position in the compound represented by Formula A undergoes a polymerization reaction (such as a condensation reaction) with an aromatic aldehyde or aromatic ketone, or other aldehydes to form the polymer.

[0046] According to an embodiment of the present invention, the polymer can be linear or have a network structure.

[0047] According to an embodiment of the present invention, the polymer comprises at least one repeating unit represented by Formula (1):

[0048]

[0049] In Formula (1), the definition of the R group is as described above; Q is derived from the compound represented by Formula A above.

[0050] According to an embodiment of the present invention, the polymer further comprises a repeating unit represented by Formula (2):

[0051]

[0052] In Formula (2), Q is derived from the compound represented by Formula A above.

[0053] According to an embodiment of the present invention, Q is derived from the polymerization residue of the compound represented by Formula A above.

[0054] According to an embodiment of the present invention, in the polymer, the degree of polymerization of the repeating unit represented by Formula (1) is an integer between 1 and 200, for example, an integer between 2 and 100, such as 10, 20, 50, 60, 80, or 100.

[0055] According to an embodiment of the present invention, in the polymer, the degree of polymerization of the repeating unit represented by Formula (2) is an integer between 0 and 200, for example, an integer between 1 and 100, such as 10, 20, 50, 60, 80, or 100.

[0056] According to an embodiment of the present invention, in the polymer, the molar number of the repeating unit represented by Formula (1) accounts for 1% - 100% of the total molar number of the repeating units of the polymer, for example, 10% - 90%, such as 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 100%.

[0057] According to an embodiment of the present invention, in the polymer, the molar number of the repeating unit represented by Formula (2) accounts for 0% - 99% of the total molar number of the repeating units of the polymer, for example, 10% - 90%, such as 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 99%.

[0058] According to an embodiment of the present invention, the weight-average molecular weight of the polymer is 1,000 - 10,000, for example, 1,000, 2,000, 3,000, 4,000, 5,000, 6,000, 7,000, 8,000, 9,000 or 10,000.

[0059] According to an embodiment of the present invention, the molecular weight distribution of the polymer is 1.2 - 3.5, for example, 1.2, 1.4, 1.5, 1.6, 1.8, 2, 2.2, 2.4, 2.5, 2.6, 2.8, 3, 3.2 or 3.5.

[0060] According to an embodiment of the present invention, the polymer has at least one of the structural formulas shown in the following formulas (1-1) to (1-10):

[0061]

[0062] Among them, Q comes from the compound shown in the above formula A, and m, m1 and m2 are degrees of polymerization.

[0063] According to an embodiment of the present invention, m is an integer between 1 and 200, for example, an integer between 2 and 100, such as 10, 20, 50, 60, 80 or 100.

[0064] According to an embodiment of the present invention, m1 + m2 is an integer between 1 and 200, for example, an integer between 2 and 100, such as 10, 20, 50, 60, 80 or 100.

[0065] <Preparation method of the polymer>

[0066] The present invention also provides a preparation method of the above polymer, and the preparation method includes the following steps:

[0067] Polymerize the compound shown in formula A with an aromatic aldehyde or an aromatic ketone under acidic conditions or alkaline conditions to obtain the polymer;

[0068] The compound shown in formula A has the following structural formula:

[0069]

[0070] Among them, the definitions of R1, R2 and k are as described above.

[0071] According to an embodiment of the present invention, the molar ratio of the compound shown in formula A to the aromatic aldehyde is 1:2 - 1:10; the molar ratio of the compound shown in formula A to the aromatic ketone is 1:2 - 1:10.

[0072] According to an embodiment of the present invention, the temperature of the polymerization reaction is 100 - 150 °C; the time of the polymerization reaction is 12 - 36 hours.

[0073] According to an embodiment of the present invention, in the polymerization reaction, other aldehydes (such as alkyl aldehydes, for example, formaldehyde, acetaldehyde, propionaldehyde, etc.) are also added.

[0074] According to an embodiment of the present invention, the molar ratio of the compound shown by formula A to the other aldehydes is 1:2 - 1:10.

[0075] According to an embodiment of the present invention, in the polymerization reaction, an acidic compound is added to obtain an acidic condition, wherein the acidic compound can be an inorganic acid or an organic acid; examples of the inorganic acid are hydrochloric acid, sulfuric acid, nitric acid or phosphoric acid, and examples of the organic acid are sulfonic acid compounds or carboxylic acid compounds, such as methanesulfonic acid, p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridinium p-toluenesulfonate, salicylic acid, camphorsulfonic acid, 5-sulfosalicylic acid, 4-chlorobenzenesulfonic acid, 4-hydroxybenzenesulfonic acid, benzenedisulfonic acid, 1-naphthalenesulfonic acid, citric acid, benzoic acid or hydroxybenzoic acid.

[0076] According to an embodiment of the present invention, in the polymerization reaction, a basic compound is added to obtain a basic condition, wherein the basic compound can be an inorganic base or an organic base; examples of the inorganic base are sodium hydroxide, barium hydroxide, potassium carbonate or ammonia water, and examples of the organic base are triethylamine or potassium tert-butoxide.

[0077] The present invention also provides a polymer prepared by the above method.

[0078] <Composition for forming a bottom spin-coated carbon coating>

[0079] As described above, the present invention provides a composition for forming a bottom spin-coated carbon coating, and the composition includes the above polymer.

[0080] According to an embodiment of the present invention, the composition for forming a bottom spin-coated carbon coating further includes at least one of a crosslinking agent, an acidic compound, a thermal acid generator and a surfactant.

[0081] <Crosslinking agent>

[0082] According to an embodiment of the present invention, as the crosslinking agent, a crosslinkable compound having at least two substituents for forming crosslinks can be used. Examples of such compounds include melamine-based compounds, substituted urea-based compounds and phenolic compounds having substituents for forming crosslinks such as hydroxymethyl and methoxymethyl.

[0083] Exemplarily, the crosslinking agent includes methoxymethylated glycoluril and methoxymethylated melamine, such as tetramethoxymethyl glycoluril, tetrabutoxymethyl glycoluril, and hexamethoxymethyl melamine (Cymel 303). The crosslinking agent includes tetrahydro-phenolic compounds, such as at least one of tetramethylol diphenol, tetramethoxymethyl diphenol (TMOM-BP), and tetramethoxymethyl bisphenol.

[0084] According to an embodiment of the present invention, as the crosslinking agent, a compound having at least two epoxy resins can be used. Examples of such compounds include at least one of tris(2,3-epoxypropyl) isocyanurate, 1,4-butanediol diglycidyl ether, 1,2-epoxy-4-(epoxyethyl) cyclohexane, glycerol triglycidyl ether, diethylene glycol diglycidyl ether, 2,6-diglycidylphenyl glycidyl ether, 1,1,3-tris[p-(2,3-epoxypropoxy)phenyl] propane, 1,2-cyclohexanedicarboxylic acid, 4,4'-methylenebis(N,N-diglycidylaniline), 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, trimethylolethane triglycidyl ether, and bisphenol A diglycidyl ether.

[0085] According to an embodiment of the present invention, as the crosslinking agent, a compound containing a vinyl ether group can be used. Examples of such compounds include at least one of bis(4-vinyloxymethyl cyclohexyl m-ethyl) glutarate, tris(ethylene glycol) divinyl ether, divinyl ester, diethylene glycol divinyl ether, 1,2,4-tris(4-vinyloxybutyl) trimellitate, 1,3,5-tris(4-vinyloxybutyl) phthalate, bis(4-(vinyloxy)butyl) terephthalate, bis(4-vinyloxy)butyl isophthalate, ethylene glycol divinyl ether, 1,4-butanediol divinyl ether, tetraethylene glycol divinyl ether, neopentyl glycol divinyl ether, trimethylolpropane trivinyl ether, trivinyl ether, hexanediol divinyl ether, divinyl ether, tetraethylene glycol divinyl ethyl ether, pentaerythritol divinyl ethyl ether, pentaerythritol trivinyl ethyl ether, and cyclohexane di-n-hexane divinyl methyl ether.

[0086] According to an embodiment of the present invention, the mass of the crosslinking agent accounts for 0.3% - 30% of the total mass of the composition, such as 0.3%, 0.5%, 0.8%, 1%, 1.5%, 2%, 3%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 25%, 28%, or 30%. The total mass of the composition refers to the total mass of the solid components remaining after removing the solvent in the composition for forming the bottom spin-coated carbon coating.

[0087] <Acidic compound>

[0088] According to an embodiment of the present invention, the acidic compound can be introduced into the composition as a catalyst for accelerating the cross-linking reaction.

[0089] According to an embodiment of the present invention, the acidic compound includes at least one of a sulfonic acid compound and a carboxylic acid compound; the acidic compound includes at least one of p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridinium p-toluenesulfonate, salicylic acid, camphorsulfonic acid, 5-sulfosalicylic acid, 4-chlorobenzenesulfonic acid, 4-hydroxybenzenesulfonic acid, benzenedisulfonic acid, 1-naphthalenesulfonic acid, citric acid, benzoic acid, and hydroxybenzoic acid.

[0090] According to an embodiment of the present invention, the mass of the acidic compound accounts for 0.1%-20% of the total mass of the composition, such as 0.1%, 0.3%, 0.5%, 0.8%, 1%, 1.5%, 2%, 3%, 5%, 6%, 8%, 10%, 12%, 15%, 18%, or 20%. The total mass of the composition refers to the total mass of the solid components remaining after removing the solvent from the composition for forming the bottom spin-coated carbon coating.

[0091] <Thermal acid generator>

[0092] According to an embodiment of the present invention, the thermal acid generator can be introduced into the composition as a catalyst for accelerating the cross-linking reaction. The thermal acid generator can be used instead of or in combination with the above acidic compound. Exemplarily, the composition includes an acidic compound and / or a thermal acid generator.

[0093] According to an embodiment of the present invention, the thermal acid generator includes a quaternary ammonium salt of trifluoromethanesulfonic acid.

[0094] According to an embodiment of the present invention, the mass of the thermal acid generator accounts for 0.1%-20% of the total mass of the composition, such as 0.1%, 0.3%, 0.5%, 0.8%, 1%, 1.5%, 2%, 3%, 5%, 6%, 8%, 10%, 12%, 15%, 18%, or 20%. The total mass of the composition refers to the total mass of the solid components remaining after removing the solvent from the composition for forming the bottom spin-coated carbon coating.

[0095] <Surfactant>

[0096] According to an embodiment of the present invention, the surfactant can improve the fluidity of the composition for forming the bottom spin-coated carbon coating, enhance the spreadability of the bottom spin-coated carbon coating, and reduce the defects of the bottom spin-coated carbon coating.

[0097] According to an embodiment of the present invention, the surfactant includes a non-ionic surfactant; the non-ionic surfactant includes polyoxyethylene alkyl ethers (such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether), polyoxyethylene alkyl aryl ethers (such as polyoxyethylene octylphenyl ether and polyoxyethylene nonylphenyl ether), polyoxyethylene-polyoxypropylene block copolymers, sorbitan fatty acid esters (such as sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, and sorbitan tristearate), polyoxyethylene sorbitan fatty acid esters (such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, fluorinated surfactants). For example, EF301, EF303, EF352, F171, F173, R-30, R-40, R-30-N, FC430, FC431, AG7 10, S-382, SC101, SC102, and silicone polymer KP341.

[0098] According to an embodiment of the present invention, the mass of the surfactant accounts for 0.01% - 5% of the total mass of the composition, for example, 0.01%, 0.02%, 0.05%, 0.08%, 0.1%, 0.3%, 0.5%, 0.8%, 1%, 1.5%, 2%, 3%, 4%, or 5%. The total mass of the composition refers to the total mass of the solid components remaining after removing the solvent in the composition for forming the bottom spin-coated carbon coating.

[0099] <Solvent>

[0100] According to an embodiment of the present invention, the composition for forming the bottom spin-coated carbon coating can be prepared by dissolving the above components in a suitable solvent and used in a homogeneous solution state.

[0101] According to an embodiment of the present invention, the composition for forming the bottom spin-coated carbon coating further includes a solvent.

[0102] According to an embodiment of the present invention, the solvent includes at least one of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monopropyl ether, propylene glycol monomethyl ether acetate, propylene glycol propyl ether acetate, ethyl lactate, ethyl acetate, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, and ethyl glycolate.

[0103] According to an embodiment of the present invention, the mass percentage of the solvent in the total mass of the composition is 70%-99%, preferably 85%-98%. The total mass of the composition refers to the total mass of the composition for forming the bottom spin-coated carbon coating, that is, the sum of the mass of the solvent and the solid components remaining after removing the solvent.

[0104] <Preparation method of the composition for forming the bottom spin-coated carbon coating>

[0105] The present invention also provides a preparation method of the above-mentioned composition for forming the bottom spin-coated carbon coating, and the method includes the following steps:

[0106] Mix the above-mentioned polymer, solvent, cross-linking agent optionally added or not, acidic compound optionally added or not, thermal acid generator optionally added or not, and surfactant optionally added or not to prepare the composition for forming the bottom spin-coated carbon coating.

[0107] <Use of the composition for forming the bottom spin-coated carbon coating>

[0108] The present invention also provides the use of the above-mentioned composition for forming the bottom spin-coated carbon coating, which is used in the field of lithography.

[0109] According to an embodiment of the present invention, the composition for forming the bottom spin-coated carbon coating is used in the field of three-layer lithography, which can achieve higher integration.

[0110] <Bottom spin-coated carbon coating>

[0111] The present invention also provides a bottom spin-coated carbon coating, which is prepared by the above-mentioned composition for forming the bottom spin-coated carbon coating.

[0112] According to an embodiment of the present invention, the above-mentioned composition for forming the bottom spin-coated carbon coating is applied to the surface of the substrate and baked to form a bottom spin-coated carbon coating on the surface of the substrate.

[0113] According to an embodiment of the present invention, the substrate is a substrate having a concave part or a convex part.

[0114] According to an embodiment of the present invention, the baking is, for example, baking using a heating device such as a hot plate. During the baking process, the solvent component in the composition volatilizes, and other components in the composition (such as polymer, cross-linking agent, acidic compound, thermal acid generator, and surfactant) undergo a cross-linking curing reaction and remain on the surface of the substrate to form a bottom spin-coated carbon coating.

[0115] According to an embodiment of the present invention, the temperature of the baking is 100°C - 240°C; the time of the baking is 0.3 minutes - 10 minutes.

[0116] <Three - layer lithography method>

[0117] The present invention also provides a three - layer lithography method, and the method comprises the following steps:

[0118] 1) Apply the composition for forming the bottom spin - on carbon coating to the surface of a substrate having a recessed part or a protruding part, bake it, and form a bottom spin - on carbon coating on the substrate surface; form an organopolysiloxane film as an anti - reflective coating on the surface of the bottom spin - on carbon coating; and form a photoresist pattern on the surface of the anti - reflective coating.

[0119] According to an embodiment of the present invention, in step 1), the baking is, for example, baking using a heating device such as a hot plate. During the baking process, the solvent component in the composition volatilizes, and other components in the composition (such as polymers, cross - linkers, acidic compounds, thermal acid generators, and surfactants) undergo a cross - linking curing reaction and remain on the substrate surface to form a bottom spin - on carbon coating.

[0120] According to an embodiment of the present invention, in step 1), the baking temperature is 100°C - 240°C; the baking time is 0.3 minutes - 10 minutes.

[0121] According to an embodiment of the present invention, in step 1), an organopolysiloxane film is formed as an anti - reflective coating on the surface of the bottom spin - on carbon coating by a method known in the art. The composition of the organopolysiloxane film is known in the art.

[0122] According to an embodiment of the present invention, in step 1), the method for forming the above - mentioned photoresist pattern is a method known in the art. For example, a predetermined area (mask) of the photoresist coating is exposed or directly drawn to perform exposure, and after development, a patterned photoresist coating is formed. As the exposure light source, for example, g - line, I - line, KrF excimer laser, ArF excimer laser, EUV, or electron beam can be used. After exposure, optionally, the exposed photoresist coating is baked, and then the resist pattern is developed with a developer (such as an aqueous solution of 2.38% by mass of tetramethylammonium hydroxide), and further rinsed with a rinsing solution or pure water to remove the excess developer. Then, the photoresist pattern is dried by baking to enhance the adhesion between the resist pattern and the bottom spin - on carbon coating.

[0123] According to an embodiment of the present invention, the method further comprises the following steps:

[0124] 2) Use the patterned photoresist coating as a mask to etch through CF4, CHF3, or C2F6 gas, transfer the pattern from the photoresist to the anti - reflective coating, and form a resist pattern.

[0125] 3) Using the anti-reflection coating as a mask, transfer the pattern from the anti-reflection coating to the bottom spin-coated carbon coating by O2, N2O or NO2 plasma etching;

[0126] 4) Using the bottom spin-coated carbon coating as a mask, transfer the pattern from the bottom spin-coated carbon coating to the substrate surface by etching with CF4, CHF3 or C2F6 gas.

[0127] The technical solution of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only for illustrative description and explanation of the present invention, and should not be construed as limiting the protection scope of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0128] The experimental methods used in the following examples are all conventional methods unless otherwise specified; the reagents, materials, etc. used in the following examples can all be obtained from commercial sources unless otherwise specified.

[0129] The structural formula of TPA-6OH used in the following examples is:

[0130]

[0131] Synthesis Example 1

[0132] Under nitrogen protection, put TPA-6OH (7.09 g, 0.0107 mol), 1-benzaldehyde (6.40 g, 0.0642 mol) and methanesulfonic acid (3.10 g, 0.0322 mol) into a 300 mL three-necked flask, add propylene glycol monomethyl ether acetate (16.59 g) to it, heat and stir the resulting mixture in an oil bath, and raise the temperature of the mixture to 120 °C for polymerization. After reacting for 24 hours, cool the mixture to room temperature, precipitate it in n-hexane (500 g), filter the precipitate and heat it in a vacuum dryer at 50 °C for 10 hours to obtain 11.56 g of the target polymer. The weight-average molecular weight Mw of the obtained polymer was measured by GPC to be 2424, and the molecular weight distribution Mw / Mn was 2.10. The polymer obtained in this synthesis example is resin BPA6OH-1 having the structure shown in formula (1-1), where Q is from TPA-6OH.

[0133] Synthesis Example 2

[0134] Under nitrogen protection, TPA-6OH (7.09 g, 0.0107 mol), 1-naphthaldehyde (10.03 g, 0.0642 mol) and methanesulfonic acid (3.10 g, 0.0322 mol) were placed in a 300 mL three-necked flask, and propylene glycol monomethyl ether acetate (20.22 g) was added thereto. The resulting mixture was heated and stirred in an oil bath, and the temperature of the mixture was raised to 120 °C for polymerization. After reacting for 24 hours, the mixture was cooled to room temperature and precipitated in n-hexane (300 g). The precipitate was filtered and heated in a vacuum dryer at 50 °C for 10 hours to obtain 11.24 g of the target polymer. The weight-average molecular weight Mw of the obtained polymer was measured by GPC to be 2850, and the molecular weight distribution Mw / Mn was 1.98. The polymer obtained in this synthesis example was resin BPA6OH-2 having the structure shown in formula (1-2), where Q was derived from TPA-6OH.

[0135] Synthesis Example 3

[0136] Under nitrogen protection, TPA-6OH (7.09 g, 0.0107 mol), 1-anthracenealdehyde (13.24 g, 0.0642 mol) and methanesulfonic acid (3.10 g, 0.0161 mol) were placed in a 300 mL three-necked flask, and propylene glycol monomethyl ether acetate (23.43 g) was added thereto. The resulting mixture was heated and stirred in an oil bath, and the temperature of the mixture was raised to 120 °C for polymerization. After reacting for 24 hours, the mixture was cooled to room temperature and precipitated in n-hexane (750 g). The precipitate was filtered and heated in a vacuum dryer at 50 °C for 10 hours to obtain 14.01 g of the target polymer. The weight-average molecular weight Mw of the obtained polymer was measured by GPC to be 2436, and the molecular weight distribution Mw / Mn was 1.24. The polymer obtained in this synthesis example was resin BPA6OH-3 having the structure shown in formula (1-3), where Q was derived from TPA-6OH.

[0137] Synthesis Example 4

[0138] Under nitrogen protection, TPA-6OH (7.09 g, 0.0107 mol), 1-pyrenecarboxaldehyde (17.72 g, 0.0642 mol) and methanesulfonic acid (3.10 g, 0.0161 mol) were placed in a 300 mL three-necked flask, and propylene glycol monomethyl ether acetate (54.00 g) was added thereto. The resulting mixture was heated and stirred in an oil bath, and the temperature of the mixture was raised to 120 °C for polymerization. After reacting for 24 hours, the mixture was cooled to room temperature and precipitated in n-hexane (1500 g). The precipitate was filtered and heated in a vacuum dryer at 50 °C for 10 hours to obtain 20.12 g of the target polymer. The weight-average molecular weight Mw of the obtained polymer was measured by GPC to be 2545, and the molecular weight distribution Mw / Mn was 1.69. The polymer obtained in this synthesis example was resin BPA6OH-4 having the structure shown in formula (1-4), where Q was derived from TPA-6OH.

[0139] Synthesis Example 5

[0140] Under nitrogen protection, TPA-6OH (7.09 g, 0.0107 mol), 1-benzaldehyde (3.20 g, 0.0321 mol), 1-naphthaldehyde (5.028 g, 0.0321 mol) and methanesulfonic acid (3.10 g, 0.0161 mol) were placed in a 300 mL three-necked flask, and propylene glycol monomethyl ether acetate (18.418 g) was added thereto. The resulting mixture was heated and stirred in an oil bath, and the temperature of the mixture was raised to 120 °C for polymerization. After reacting for 24 hours, the mixture was cooled to room temperature and precipitated in n-hexane (500 g). The precipitate was filtered and heated in a vacuum dryer at 50 °C for 10 hours to obtain 12.22 g of the target polymer. The weight-average molecular weight Mw of the obtained polymer was measured by GPC to be 2622, and the molecular weight distribution Mw / Mn was 1.89. The polymer obtained in this synthesis example was resin BPA6OH-5 having the structure shown in formula (1-5), where Q was derived from TPA-6OH.

[0141] Synthesis Example 6

[0142] Under nitrogen protection, TPA-6OH (7.09 g, 0.0107 mol), 1-naphthaldehyde (5.028 g, 0.0321 mol), 1-anthracenealdehyde (6.62 g, 0.0321 mol) and methanesulfonic acid (3.10 g, 0.0161 mol) were placed in a 300 mL three-necked flask, and propylene glycol monomethyl ether acetate (21.84 g) was added thereto. The resulting mixture was heated with stirring in an oil bath, and the temperature of the mixture was raised to 120 °C for polymerization. After reacting for 24 hours, the mixture was cooled to room temperature and precipitated in n-hexane (500 g). The precipitate was filtered and heated in a vacuum dryer at 50 °C for 10 hours to obtain 13.56 g of the target polymer. The weight-average molecular weight Mw was measured by GPC to be 2798, and the molecular weight distribution Mw / Mn was 1.81. The polymer obtained in this synthesis example was resin BPA6OH-6 having the structure shown in formula (1-8), wherein Q was derived from TPA-6OH.

[0143] Synthesis Example 7

[0144] Under nitrogen protection, TPA-6OH (7.09 g, 0.0107 mol), 1-anthracenealdehyde (6.62 g, 0.0321 mol), 1-pyrenealdehyde (8.86 g, 0.0321 mol) and methanesulfonic acid (3.10 g, 0.0322 mol) were placed in a 300 mL three-necked flask, and propylene glycol monomethyl ether acetate (25.67 g) was added thereto. The resulting mixture was heated with stirring in an oil bath, and the temperature of the mixture was raised to 120 °C for polymerization. After reacting for 24 hours, the mixture was cooled to room temperature and precipitated in n-hexane (500 g). The precipitate was filtered and heated in a vacuum dryer at 120 °C for 10 hours to obtain 11.45 g of the target polymer. The weight-average molecular weight Mw was measured by GPC to be 2988, and the molecular weight distribution Mw / Mn was 1.65. The polymer obtained in this synthesis example was resin BPA6OH-7 having the structure shown in formula (1-10), wherein Q was derived from TPA-6OH.

[0145] Example 1

[0146] 10 g of the polymer obtained in Synthesis Example 1 was mixed with 0.03 g of surfactant R-40 (a fluorocarbon surfactant (purchased from DIC Corporation)) and 40 g of cyclohexanone to obtain a solution. This solution was filtered through a 0.22 μm polyethylene microporous filter to obtain a clear filtrate, which was then used to prepare a composition for forming a bottom spin-coated carbon coating for a lithography process.

[0147] Example 2

[0148] 10 g of the polymer obtained in Synthesis Example 2 was mixed with 0.03 g of surfactant R-40 (a fluorocarbon surfactant (purchased from DIC Corporation)) and 40 g of cyclohexanone to obtain a solution. This solution was filtered through a 0.22-μm polyethylene microporous filter to obtain a clear filtrate, thereby preparing a composition for forming a bottom spin-coated carbon coating for use in a lithography process.

[0149] Example 3

[0150] 10 g of the polymer obtained in Synthesis Example 3 was mixed with 0.03 g of surfactant R-40 (a fluorocarbon surfactant (purchased from DIC Corporation)) and 40 g of cyclohexanone to obtain a solution. This solution was filtered through a 0.22-μm polyethylene microporous filter to obtain a clear filtrate, thereby preparing a composition for forming a bottom spin-coated carbon coating for use in a lithography process.

[0151] Example 4

[0152] 10 g of the polymer obtained in Synthesis Example 4 was mixed with 0.03 g of surfactant R-40 (a fluorocarbon surfactant (purchased from DIC Corporation)) and 40 g of cyclohexanone to obtain a solution. This solution was filtered through a 0.22-μm polyethylene microporous filter to obtain a clear filtrate, thereby preparing a composition for forming a bottom spin-coated carbon coating for use in a lithography process.

[0153] Example 5

[0154] 10 g of the polymer obtained in Synthesis Example 5 was mixed with 0.03 g of surfactant R-40 (a fluorocarbon surfactant (purchased from DIC Corporation)) and 40 g of cyclohexanone to obtain a solution. This solution was filtered through a 0.22-μm polyethylene microporous filter to obtain a clear filtrate, thereby preparing a composition for forming a bottom spin-coated carbon coating for use in a lithography process.

[0155] Example 6

[0156] 10 g of the polymer obtained in Synthesis Example 6 was mixed with 0.03 g of surfactant R-40 (a fluorocarbon surfactant (purchased from DIC Corporation)) and 40 g of cyclohexanone to obtain a solution. This solution was filtered through a 0.22-μm polyethylene microporous filter to obtain a clear filtrate, thereby preparing a composition for forming a bottom spin-coated carbon coating for use in a lithography process.

[0157] Example 7

[0158] 10 g of the polymer obtained in Synthesis Example 7 was mixed with 0.03 g of surfactant R-40 (a fluorocarbon surfactant (purchased from DIC Corporation)) and 40 g of cyclohexanone to obtain a solution. This solution was filtered through a 0.22-μm polyethylene microporous filter to obtain a clear filtrate, thereby preparing a composition for forming a bottom spin-coated carbon coating for use in a lithography process.

[0159] Comparative Example 1

[0160] 20 g of commercially available cresol novolac resin (a phenolic resin obtained by using cresol and formaldehyde, with a weight-average molecular weight Mw measured by GPC of 4000 and a molecular weight distribution Mw / Mn of 2.1) was mixed with 0.06 g of surfactant R-40 (a fluorocarbon surfactant (purchased from DIC Corporation)) and 80 g of propylene glycol monomethyl ether to obtain a solution. This solution was filtered through a 0.22-micron polyethylene microporous filter to obtain a clear filtrate, which was then used to prepare a composition for forming a bottom spin-coated carbon coating for use in a lithography process.

[0161] Test Example 1: Peeling test of the bottom spin-coated carbon coating in a photoresist solvent

[0162] The compositions of Examples 1-7 and Comparative Example 1 were spin-coated on 4-inch silicon wafers at 1500 rpm and then baked on a hot plate at 240°C for 1 minute to form a bottom spin-coated carbon coating. The thickness of the carbon coating was measured using a film thickness gauge and denoted as T1. The formed bottom spin-coated carbon coatings were respectively immersed in propylene glycol monomethyl ether acetate for 1 minute, dried with nitrogen, and then the thickness of the carbon coating was measured again using a film thickness gauge and denoted as T2. The peeling rate S was calculated as S = (T1 - T2) / T1 * 100%. The test results are shown in Table 1.

[0163] Table 1: Results of the peeling test of the bottom spin-coated carbon coating in a photoresist solvent

[0164] <![CDATA[T1(nm)]]> <![CDATA[T2(nm)]]> <![CDATA[T1-T2]]> Peeling Rate S Example 1 265.6 265.2 0.34 0.13％ Example 2 299.2 298.9 0.31 0.10％ Example 3 268.6 268.1 0.45 0.17％ Example 4 271.2 270.7 0.52 0.19％ Example 5 281.5 281.2 0.24 0.09％ Example 6 275.6 275.2 0.44 0.16％ Example 7 269.4 269.2 0.2 0.07％ Comparative Example 1 285.5 285.0 0.44 0.15％

[0165] From the peeling test results in Table 1, it can be seen that the peeling rates S of the bottom spin-coated carbon coatings formed in Examples 1-7 and Comparative Example 1 are all < 1%, indicating that the formed bottom spin-coated carbon coatings have good anti-peeling effects, showing that the compositions for forming the bottom spin-coated carbon coatings are insoluble in photoresist solvents and meet the photoresist compatibility requirements.

[0166] Test Example 2: Measurement of dry etching rate

[0167] The compositions of Examples 1-7 and Comparative Example 1 were spin-coated on 4-inch silicon wafers at 1500 rpm and then baked on a hot plate at 240°C for 1 minute to form a bottom spin-coated carbon coating. CF4 gas was used as the etching gas to measure the dry etching rate of the bottom spin-coated carbon coating.

[0168] Assuming the dry etching rate of the bottom spin-coated carbon coating formed in Comparative Example 1 is 1.00, the dry etching rates of the bottom spin-coated carbon coatings formed in Examples 1-7 were calculated as dry etching rate ratios. The smaller the dry etching rate ratio, the higher the resistance to etching with CF4 gas.

[0169] Dry etching rate ratio = (Dry etching rate of bottom spin-coated carbon coating) / (Dry etching rate of Comparative Example 1).

[0170] Table 2 Dry etching rate ratio of bottom spin-coated carbon coating

[0171] Dry Etching Rate Ratio Example 1 0.85 Example 2 0.80 Example 3 0.78 Example 4 0.77 Example 5 0.76 Example 6 0.78 Example 7 0.74 Comparative Example 1 1.00

[0172] From the performance test results in Table 2, it can be seen that the dry etching rate ratios of the bottom spin-coated carbon coatings obtained in the present invention are all < 1, indicating that they have higher etch resistance compared to the bottom spin-coated carbon coating of Comparative Example 1.

[0173] Test Example 3 Thermal stability test of bottom spin-coated carbon coating composition

[0174] The compositions of Examples 1 - 7 and Comparative Example 1 were spin-coated on 4-inch silicon wafers at a speed of 1500 rpm and then baked on a hot plate at 240°C for 1 minute to form bottom spin-coated carbon coatings. A comprehensive thermal analyzer was used to detect the temperature at which the bottom spin-coated carbon coating on the silicon wafer lost 5% of its weight.

[0175] Table 3 Temperature at which the bottom spin-coated carbon coating loses 5% of its weight

[0176] Temperature at 5% Weight Loss / °C Example 1 376 Example 2 401 Example 3 429 Example 4 423 Example 5 349 Example 6 346 Example 7 343 Comparative Example 1 254

[0177] The bottom spin-coated carbon coating needs to undergo high-temperature treatment in the lithography process, so it requires high thermal stability. A bottom spin-coated carbon coating with high thermal stability can maintain the clarity and stability of the pattern at high temperatures.

[0178] From the performance test results in Table 3, it can be seen that compared with Comparative Example 1, the temperatures at which the bottom spin-coated carbon coatings formed by the compositions for forming bottom spin-coated carbon coatings of the present invention lose 5% of their weight are all higher than 340°C, indicating that they have higher thermal stability.

[0179] Test Example 4 Filling test

[0180] The compositions for forming bottom spin-coated carbon coatings of Example 3 and Comparative Example 1 were spin-coated on a silicon wafer substrate with a hole pattern of a diameter of 100 nm and a height of 400 nm at a speed of 1500 rpm and then baked on a hot plate at 240°C for 1 minute to form bottom spin-coated carbon coatings.

[0181] Figure 1 Figure [ID number] is a scanning electron microscope image of the silicon wafer substrate formed after spin-coating the composition for forming the bottom spin-coated carbon coating of Example 3. Figure 2 Figure [ID number] is a scanning electron microscope image of the silicon wafer substrate formed after spin-coating the composition for forming the bottom spin-coated carbon coating of Comparative Example 1. Observe the cross-sectional SEM photograph of the silicon wafer substrate under a scanning electron microscope (SEM) (comparison Figure 1 and Figure 2), it is found that both of them have good filling performance as the bottom spin-coated carbon coating.

[0182] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above embodiments. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A polymer which is a polymer formed by the polymerization reaction of a compound represented by Formula A with an aromatic aldehyde or an aromatic ketone: In formula A, R1 are the same or different and are independently selected from hydroxy, C 1-12 alkoxy, C 1-12 alkyl, -CH(O-C 1-12 alkyl)-O-C 1-12 alkyl, -C(=O)-C 1-12 alkyl or glycidyl; R2 are the same or different and are independently selected from a hydrogen atom, C 1-12 alkyl; k are the same or different and are independently 0 or 1, and at least one hydroxy group is contained on the four phenyl groups attached with -(R1) k and -OR2 located at the periphery of the compound represented by formula A.

2. The polymer according to claim 1, wherein, In formula A, R1 are the same or different and are independently selected from hydroxy, C 1-6 alkoxy, C 1-6 alkyl, -CH(O-C 1-6 alkyl)-O-C 1-6 alkyl, -C(=O)-C 1-6 alkyl or glycidyl; R2 are the same or different and are independently selected from a hydrogen atom or C 1-6 alkyl; k are the same or different and are independently 0 or 1, and at least one hydroxy group is contained on the four phenyl groups attached with -(R1) k and -OR2 located at the periphery of the compound represented by formula A.

3. The polymer according to claim 1, wherein, In Formula A, R2 are all H; And / or, in formula A, the four phenyl groups attached with -(R1) k and -OR2 located at the periphery of the compound represented by formula A contain at least two hydroxyl groups.

4. The polymer according to claim 1, wherein In formula A, at least two of the four phenyl groups attached to -(R1) k and -OR2 on the periphery of the compound represented by formula A each have at least one hydroxyl group.

5. The polymer according to claim 1, wherein, The compound represented by Formula A has the following structure:

6. The polymer according to claim 1, wherein The aromatic aldehyde is an aldehyde containing an aromatic group, and the structural formula of the aromatic aldehyde is R-CHO, where R is an aryl group, heteroaryl group, arylalkyl group, or heteroarylalkyl group which is unsubstituted or optionally substituted by 1-3 Ra. When substituted, the substituents are alkyl group, alkoxy group, hydroxyl group, amino group, -NH(alkyl), -N(alkyl)2, -OCO-alkyl or -CO-alkyl.

7. The polymer according to claim 1, wherein The aromatic aldehyde includes at least one of furfural, benzaldehyde, naphthaldehyde, anthracene aldehyde, phenanthrene aldehyde, pyrene aldehyde, salicylaldehyde, phenylacetaldehyde, 3-phenylpropionaldehyde, tolyl aldehyde, (N,N-dimethylamino)benzaldehyde, acetoxybenzaldehyde, and anisaldehyde.

8. The polymer according to claim 1, wherein The aromatic ketone is a ketone containing an aromatic group, and the structural formula of the aromatic ketone is R-CO-R’, where R and R’ are the same or different and are independently an aryl group, heteroaryl group, arylalkyl group, or heteroarylalkyl group which is unsubstituted or optionally substituted by 1-3 Ra. When substituted, the substituents are alkyl group, alkoxy group, hydroxyl group, amino group, -NH(alkyl), -N(alkyl)2, -OCO-alkyl or -CO-alkyl.

9. The polymer according to claim 1, wherein The aromatic ketone includes diaryl ketone.

10. The polymer according to claim 9, wherein, The diaryl ketone is selected from at least one of benzophenone, phenylnaphthyl ketone, dinaphthyl ketone, phenyltolyl ketone, xylenyl ketone, and 9-fluorenone.

11. The polymer according to claim 1, wherein, The polymer is a polymer formed by the polymerization reaction of the compound represented by Formula A, an aromatic aldehyde or an aromatic ketone, and formaldehyde.

12. The polymer according to claim 1, wherein, The polymer includes at least one repeating unit represented by Formula (1): In Formula (1), R is an aryl group, heteroaryl group, arylalkyl group, or heteroarylalkyl group which is unsubstituted or optionally substituted by 1-3 Ra. When substituted, the substituents are alkyl group, alkoxy group, hydroxyl group, amino group, -NH(alkyl), -N(alkyl)2, -OCO-alkyl or -CO-alkyl; Q is derived from the compound represented by Formula A above.

13. The polymer according to claim 12, wherein, The polymer further includes a repeating unit represented by Formula (2): In Formula (2), Q is derived from the compound represented by Formula A above.

14. The polymer according to claim 12, wherein, In the polymer, the degree of polymerization of the repeating unit represented by Formula (1) is an integer between 1 and 200.

15. The polymer according to claim 13, wherein, In the polymer, the degree of polymerization of the repeating unit represented by Formula (2) is an integer between 0 and 200.

16. The polymer according to claim 12, wherein, In the polymer, the mole number of the repeating unit represented by Formula (1) accounts for 1%-100% of the total mole number of the repeating units of the polymer.

17. The polymer according to claim 13, wherein, In the polymer, the mole number of the repeating unit represented by Formula (2) accounts for 0%-99% of the total mole number of the repeating units of the polymer.

18. The polymer according to claim 1, wherein, The weight-average molecular weight of the polymer is 1000-10000.

19. The polymer according to claim 1, wherein, The molecular weight distribution of the polymer is 1.2-3.

5.

20. The polymer according to claim 1, wherein The polymer has at least one of the structural formulas represented by Formula (1-1) to Formula (1-10) as follows: Among them, Q is from the compound represented by Formula A above, and m, m1, and m2 are degrees of polymerization; m is an integer between 1 and 200, and m1 + m2 is an integer between 1 and 200.

21. A method for preparing the polymer according to any one of claims 1-20, the preparation method comprising the following steps: Polymerizing a compound represented by formula A with an aromatic aldehyde or an aromatic ketone under acidic conditions or basic conditions to obtain the polymer; The compound represented by formula A has the following structural formula: Among them, R1 is the same or different and is independently selected from hydroxy, C 1-12 alkoxy, C 1-12 alkyl, -CH(O-C 1-12 alkyl)-O-C 1-12 alkyl, -C(=O)-C 1-12 alkyl or glycidyl; R2 is the same or different and is independently selected from a hydrogen atom, C 1-12 alkyl; k is the same or different and is independently 0 or 1, and at least one hydroxy group is contained in the four phenyl groups attached with -(R1) k and -OR2 on the periphery of the compound shown in formula A.

22. The preparation method according to claim 21, wherein, The molar ratio of the compound represented by formula A to the aromatic aldehyde is 1:2 - 1:10; the molar ratio of the compound represented by formula A to the aromatic ketone is 1:2 - 1:10; The temperature of the polymerization reaction is 100 - 150 °C; the time of the polymerization reaction is 12 - 36 hours.

23. The preparation method according to claim 21, wherein Formaldehyde is added in the polymerization reaction.

24. The preparation method according to claim 23, wherein, The molar ratio of the compound represented by formula A to formaldehyde is 1:2 - 1:

10.

25. A polymer prepared by the method according to any one of claims 21-24.

26. A composition for forming a bottom spin-coated carbon coating, wherein, The composition comprises the polymer according to any one of claims 1-20, 25.

27. The composition for forming a bottom spin-coated carbon coating according to claim 26, wherein, The composition for forming a bottom spin-coated carbon coating further comprises at least one of a crosslinking agent, an acidic compound, a thermal acid generator, and a surfactant.

28. The composition for forming a bottom spin-coated carbon coating according to claim 26 or 27, wherein, The composition for forming a bottom spin-coated carbon coating further comprises a solvent.

29. Use of the composition for forming a bottom spin-coated carbon coating according to any one of claims 26-28 in the field of lithography.

30. A bottom spin-coated carbon coating, wherein, The bottom spin-coated carbon coating is prepared by the composition for forming a bottom spin-coated carbon coating according to any one of claims 26-28.

31. The bottom spin-coated carbon coating according to claim 30, wherein, Applying the composition for forming a bottom spin-coated carbon coating to the surface of a substrate, baking, and forming a bottom spin-coated carbon coating on the surface of the substrate.

32. The bottom spin-coated carbon coating according to claim 31, wherein, The temperature of the baking is 100 °C - 240 °C; the time of the baking is 0.3 minutes - 10 minutes.

33. A three-layer lithography method, wherein, The method comprises the following steps: 1) Applying the composition for forming a bottom spin-coated carbon coating according to any one of claims 26-28 to the surface of a substrate having a recessed part or a protruding part, baking, and forming a bottom spin-coated carbon coating on the surface of the substrate; Forming an organopolysiloxane film as an antireflection coating on the surface of the bottom spin-coated carbon coating; Forming a photoresist pattern on the surface of the antireflection coating.

34. The three-layer lithography method according to claim 33, wherein, In step 1), the temperature of the baking is 100 °C - 240 °C; the time of the baking is 0.3 minutes - 10 minutes.

35. The three-layer lithography method according to claim 33, wherein, The method further comprises the following steps: 2) Using the patterned photoresist coating as a mask to etch through CF4, CHF3, or C2F6 gas, and transferring the pattern from the photoresist to the antireflection coating to form a resist pattern; 3) Using the antireflection coating as a mask to etch through O2, N2O, or NO2 plasma, and transferring the pattern from the antireflection coating to the bottom spin-coated carbon coating; 4) Using the bottom spin-coated carbon coating as a mask to etch through CF4, CHF3, or C2F6 gas, and transferring the pattern from the bottom spin-coated carbon coating to the surface of the substrate.

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