Resist underlayer film monomer, resist underlayer film composition, and pattern forming method

Abstract

The present invention belongs to the field of photolithography, and specifically relates to a resist underlayer film monomer, a resist underlayer film composition, and a pattern forming method. The resist underlayer film composition contains a resist underlayer film monomer as shown in formula (1), an aromatic polymer, and a solvent. The key to the present invention is the introduction of a resist underlayer film monomer containing a triptycene benzoxazine structure. On the one hand, the triptycene structure with a high carbon content can improve the etching resistance of the resist underlayer film. On the other hand, the resist underlayer film monomer containing the triptycene benzoxazine structure has good structural stability and can be cross-linked under heating conditions, so that the formed resist underlayer film has improved heat resistance and etching resistance. It also reduces the hydrophilicity of the resist underlayer film and improves its adhesion to the photoresist surface, so that the photoresist pattern after development is not easy to collapse, the line width roughness (LWR) of the photoresist pattern is small, and the patterning effect is good.

Description

Technical Field

[0001] The invention belongs to the field of photolithography, and in particular relates to a resist underlayer film monomer, a resist underlayer film composition and a pattern forming method. Background Art

[0002] In recent years, with the growing demand for higher integration and higher speeds in semiconductor devices, methods for further improving the refinement of photolithographic patterns have been sought. To achieve this, various technologies have been developed for the light sources used to produce fine and high-precision patterns. For low-density applications, exposure using the g-line (436nm) or i-line (365nm) of a mercury lamp is widely used. For applications requiring higher integration and refinement, shorter-wavelength KrF excimer lasers (248nm) and ArF excimer lasers (193nm) are becoming practical. In the cutting-edge era where further refinement of patterns is required, exposure using extreme ultraviolet (EUV, 13.5nm) light is also becoming practical.

[0003] Photolithography technology includes: providing a material layer on a semiconductor substrate; coating a photoresist layer on the material layer; exposing and developing the photoresist layer to provide a photoresist pattern; and etching the material layer using the photoresist pattern as a mask. Currently, due to the smaller size requirements of the patterns to be formed in the future, it is difficult to provide fine patterns with clear outlines using only the typical photolithography technology mentioned above. Therefore, an intermediate layer called a hard mask or resist underlayer film can be formed between the material layer and the photoresist layer to provide a fine pattern. The intermediate layer is used to transfer the fine pattern of the photoresist to the material layer through a selective etching process. Therefore, the resist underlayer film needs to have characteristics such as heat resistance and etching resistance to ensure that it has good tolerance during multiple etching processes, thereby facilitating the transfer and formation of fine patterns. Currently, existing resist underlayer films have problems such as poor tolerance and poor adhesion to the photoresist layer, which affect the photoresist pattern formation effect. Summary of the Invention

[0004] The purpose of the present invention is to address the problem that the resist underlayer film prepared by the prior art has poor tolerance and poor adhesion to the photoresist layer, which affects the photoresist pattern formation effect. The present invention provides a resist underlayer film monomer. The resist underlayer film composition containing the monomer can not only improve the heat resistance and etching resistance of the resist underlayer film, but also has good adhesion to the photoresist layer, thereby facilitating the acquisition of a fine photolithography pattern with good formation effect and no collapse.

[0005] In a first aspect, the present invention provides a resist underlayer film monomer. The resist underlayer film monomer has a structure as shown in formula (1):

[0006]

[0007] In formula (1), R1 is a C1-C6 alkyl group or a C6-C 30 R2 and R3 are each independently a hydrogen atom, a hydroxyl group, a C1-C 10 Alkyl, C3~C 10 The monocyclic or polycyclic unsaturated group or R2 and R3 together with the benzene ring to which they are connected form an unsubstituted or C6-C 30 The benzoxazine structure is substituted with an aromatic group, R4 and R5 are each independently a hydrogen atom, a hydroxyl group, a C1 to C2 group containing or not containing heteroatoms 10 Alkyl, C3~C 10 The monocyclic or polycyclic unsaturated group or R2 and R3 together with the benzene ring to which they are connected form an unsubstituted or C6-C 30 Aryl-substituted benzoxazine structure.

[0008] In a preferred embodiment, the resist underlayer film monomer is selected from at least one of the compounds having the structures represented by formula (1-1), formula (1-2), and formula (1-3):

[0009]

[0010]

[0011] In formula (1-1), formula (1-2) and formula (1-3), R 11 ~R 16 Each independently is a C1 to C6 alkyl group or a C6 to C 30 of aromatic groups.

[0012] In a preferred embodiment, R 11 ~R 16 Each independently is C6~C 30 of aromatic groups.

[0013] In a second aspect, the present invention provides a resist underlayer film composition comprising the resist underlayer film monomer, an aromatic polymer, and a solvent.

[0014] In a preferred embodiment, the mass ratio of the resist underlayer film monomer to the aromatic polymer is 1:(0.1-10).

[0015] In a preferred embodiment, the total mass content of the resist underlayer film monomer and the aromatic polymer is 10 to 25 wt % based on the total mass of the resist underlayer film composition.

[0016] In a preferred embodiment, the aromatic polymer contains structural units represented by formula (2) and / or formula (3):

[0017]

[0018] In formula (2) and formula (3), Ar1 and Ar2 are each independently substituted or unsubstituted C6 to C 30 R6 is a hydrogen atom or a C6~C 16 wherein n is an integer of 1 to 200.

[0019] In a preferred embodiment, Ar1 and Ar2 are each independently selected from at least one of the structures represented by formula (2-1), formula (2-2), and formula (2-3):

[0020]

[0021] In formula (2-1), formula (2-2) and formula (2-3), It represents the bond between the Ar1 or Ar2 group and other structural units.

[0022] In a preferred embodiment, the weight average molecular weight of the aromatic polymer is preferably 500 to 6000 g / mol, and the polydispersity is 1.5 to 2.5.

[0023] In a preferred embodiment, the solvent is selected from at least one of propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, cyclohexanone and ethyl lactate.

[0024] In a preferred embodiment, the resist underlayer film composition further contains a catalyst and / or a surfactant.

[0025] In a preferred embodiment, the catalyst is selected from at least one of acidic compounds.

[0026] In a preferred embodiment, the surfactant is at least one selected from polyoxyethylene alkyl ethers, polyoxyethylene alkyl aryl ethers, sorbitan fatty acid esters and polyoxyethylene sorbitan fatty acid esters.

[0027] In a third aspect, the present invention provides a resist underlayer film, which is obtained by coating the resist underlayer film composition on a substrate and subjecting the substrate to heat treatment.

[0028] In a fourth aspect, the present invention also provides a pattern forming method. The method comprises: forming a material layer on a substrate; applying the resist underlayer film composition described above onto the material layer and performing a heat treatment to form a resist underlayer film; forming a photoresist layer on the resist underlayer film; exposing and developing the photoresist layer to form a photoresist pattern; removing the resist underlayer film using the photoresist pattern as a mask to expose a portion of the material layer; and etching the exposed portion of the material layer.

[0029] Beneficial effects: The resist underlayer film monomer provided by the present invention contains a triptycene benzoxazine structure. On the one hand, the triptycene structure with a high carbon content can improve the etching resistance of the resist underlayer film. On the other hand, the resist underlayer film monomer containing the triptycene benzoxazine structure has good structural stability and can undergo self-polymerization or polymerization with an aromatic polymer under heating conditions, so that the resist underlayer film formed by the composition containing the resist underlayer film monomer has improved heat resistance and etching resistance. At the same time, the introduction of the resist underlayer film monomer with this specific structure also reduces the hydrophilicity of the resist underlayer film and improves its adhesion to the photoresist surface, so that the photoresist pattern after development is not easy to collapse, the line width roughness (LWR) of the photoresist pattern is small, and the patterning effect is good, which can well meet the application requirements of refined photoresist patterns. DETAILED DESCRIPTION

[0030] The resist underlayer film monomer provided by the present invention has a structure as shown in formula (1):

[0031]

[0032] In formula (1), R1 is a C1-C6 alkyl group or a C6-C 30 R2 and R3 are each independently a hydrogen atom, a hydroxyl group, a C1-C 10 Alkyl, C3~C 10 The monocyclic or polycyclic unsaturated group or R2 and R3 together with the benzene ring to which they are connected form an unsubstituted or C6-C 30 The benzoxazine structure is substituted with an aromatic group, R4 and R5 are each independently a hydrogen atom, a hydroxyl group, a C1 to C2 group containing or not containing heteroatoms, 10 Alkyl, C3~C 10 The monocyclic or polycyclic unsaturated group or R2 and R3 together with the benzene ring to which they are connected form an unsubstituted or C6-C 30 The heteroatom is selected from at least one of an oxygen atom, a nitrogen atom and a sulfur atom.

[0033] Specific examples of C1-C6 alkyl groups include, but are not limited to, at least one of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl, 2,2-dimethylpropyl, 1,2-dimethylpropyl, 1-ethylpropyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, 3,3-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, and 3-ethylbutyl. 30 Specific examples of the aryl group include, but are not limited to, at least one of phenyl, naphthyl, anthracenyl, phenanthrenyl, pyrenyl, benzopyrenyl, diphenylfluorenyl, and biphenyl. 10 Specific examples of the alkyl group include, but are not limited to, at least one of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl, 2,2-dimethylpropyl, 1,2-dimethylpropyl, 1-ethylpropyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, 3,3-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 3-ethylbutyl, n-heptyl, n-octyl, n-nonyl, and n-hexyl. 10 Specific examples of the monocyclic or polycyclic unsaturated groups include, but are not limited to, at least one of pyridyl, pyrrolyl, furyl, thienyl, and indolyl. 10 Specific examples of the monocyclic or polycyclic unsaturated group include, but are not limited to, at least one of cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, cyclononenyl, cyclodecenyl, phenyl, and naphthyl.

[0034] In the present invention, the resist underlayer film monomer is preferably at least one selected from the group consisting of compounds having structures represented by formula (1-1), formula (1-2), and formula (1-3):

[0035]

[0036] In formula (1-1), formula (1-2) and formula (1-3), R 11 ~R 16 Each independently preferably is a C1 to C6 alkyl group or a C6 to C 30 The aryl group is more preferably C6~C 30Of which, C1 to C6 alkyl and C6 to C 30 Specific examples of the aryl group are as described above and are not detailed here.

[0037] The resist underlayer film composition provided by the present invention contains the above-mentioned resist underlayer film monomer, an aromatic polymer and a solvent.

[0038] The resist underlayer film monomer provided by the present invention contains a benzoxazine structure. Under the action of heat, a ring-opening polymerization reaction will occur as described below, generating a nitrogen-containing network structure similar to a phenolic resin. During the curing process, no small molecules are released and the volume shrinkage rate is approximately zero, eliminating the concern of contaminating the resist underlayer film and equipment.

[0039]

[0040] In the present invention, the mass ratio of the resist underlayer film monomer to the aromatic polymer is preferably 1:(0.1-10), such as 1:0.1, 1:0.2, 1:0.5, 1:0.5, 1:1, 1:2, 1:5, 1:8, 1:10, or any value therebetween. The mass ratio of the resist underlayer film monomer to the aromatic polymer is more preferably 1:(0.6-1.6), such as 1:0.6, 1:0.8, 1:1, 1:1.2, 1:1.3, 1:1.4, 1:1.6, or any value therebetween, which is more conducive to forming a resist underlayer film with uniform film thickness.

[0041] In the present invention, the sum of the weight content of the resist underlayer film monomer and the aromatic polymer is preferably 10 to 25 wt%, such as 10 wt%, 12 wt%, 14 wt%, 18 wt%, 20 wt%, 22 wt%, 25 wt%, or any value therebetween, based on the total weight of the resist underlayer film composition. This is more conducive to the formed resist underlayer film having good etching resistance.

[0042] In the present invention, the aromatic polymer preferably contains structural units represented by formula (2) and / or formula (3):

[0043]

[0044] In formula (2) and formula (3), Ar1 and Ar2 are each independently substituted or unsubstituted C6 to C 30 R6 is a hydrogen atom or a C6~C 16 wherein n is an integer from 1 to 200. 30 Specific examples of the aryl group are as described above. 16Specific examples of the aryl group include, but are not limited to, at least one of phenyl, naphthyl, anthracenyl, pyrenyl, and biphenyl. n can be 1, 2, 5, 10, 20, 50, 80, 100, 150, 200, or any integer therebetween.

[0045] In the present invention, the aromatic polymer can be any polymer containing structural units as shown in formula (2) and / or formula (3), and can be purchased from the market or prepared based on existing disclosed preparation methods or preparation principles.

[0046] In a specific embodiment, Ar1 and Ar2 are each independently selected from at least one of the structures represented by formula (2-1), formula (2-2), and formula (2-3):

[0047]

[0048] In formula (2-1), formula (2-2) and formula (2-3), It represents the bond between the Ar1 or Ar2 group and other structural units.

[0049] In the present invention, the preparation method of the aromatic polymer preferably includes method 1 and / or method 2. Method 1 preferably includes the following steps: performing a polycondensation reaction on an aromatic phenol compound containing Ar1 and an aldehyde compound containing R6 under the condition of an acidic catalyst, and the resulting reaction product is an aromatic polymer containing a structural unit as shown in formula (2). Method 2 preferably includes the following steps: performing a polycondensation reaction on an aromatic phenol compound containing Ar1 or Ar2 and formaldehyde or paraformaldehyde under the condition of an acidic catalyst, and the resulting reaction product is an aromatic polymer containing a structural unit as shown in formula (3).

[0050] In a specific embodiment, specific examples of the aromatic phenolic compound containing Ar1 and the aromatic phenolic compound containing Ar2 independently include, but are not limited to, at least one of phenol, 1-naphthol, 2-naphthol, 1-hydroxyanthracene, 9-hydroxyanthracene, 1-hydroxypyrene, and 4,4'-(9-fluorenylene)diphenol. Specific examples of the aldehyde compound containing R6 include, but are not limited to, at least one of benzaldehyde, naphthaldehyde, anthracene formaldehyde, and pyrene formaldehyde. The acidic catalyst may be an organic acid or an inorganic acid, wherein the inorganic acid may be selected from at least one of sulfuric acid, phosphoric acid, perchloric acid, and nitric acid, and the organic acid may be selected from at least one of p-toluenesulfonic acid, formic acid, and oxalic acid. The polycondensation reaction is typically carried out in a solvent, which may be any of various existing inert liquids that do not hinder the polycondensation reaction. Specific examples include, but are not limited to, at least one of tetralin, tetrahydrofuran, propylene glycol monomethyl ether, and propylene glycol monomethyl ether. The conditions for the polycondensation reaction may be selected based on existing methods for preparing aromatic polymers. Preferably, the polycondensation reaction is carried out under an inert gas atmosphere at a reaction temperature of 100 to 200° C. The reaction time is selected according to the actual reaction temperature and molecular weight, and is usually 2 to 20 hours.

[0051] In the present invention, the weight average molecular weight (Mw) of the aromatic polymer is preferably 500 to 6000 g / mol, such as 500 g / mol, 800 g / mol, 1000 g / mol, 2000 g / mol, 4000 g / mol, 6000 g / mol or any value therebetween; the polydispersity is preferably 1.5 to 2.5, such as 1.5, 1.8, 2.0, 2.2, 2.5 or any value therebetween.

[0052] In the present invention, the solvent can be any liquid substance that has sufficient solubility or dispersibility for the resist lower film monomer and the aromatic polymer, and specific examples thereof include but are not limited to at least one of propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), cyclohexanone and ethyl lactate.

[0053] In the present invention, the resist underlayer film composition preferably further contains a catalyst and / or a surfactant.

[0054] In the present invention, the catalyst can be a substance that promotes the cross-linking reaction, preferably an acidic substance, and specific examples thereof include but are not limited to at least one of p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridinium-p-toluenesulfonate, salicylic acid, camphorsulfonic acid and benzene disulfonic acid.

[0055] In the present invention, the surfactant is beneficial to further improve the film-forming quality of the resist lower layer film and reduce the occurrence of defects such as pinholes and stripes. Specific examples of the surfactant include, but are not limited to, 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 octylphenol ether and polyoxyethylene nonylphenol ether; sorbitan fatty acid esters such as sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan monotrioleate, and sorbitan tristearate; and at least one of polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene-sorbitan monolaurate, polyoxyethylene-sorbitan monopalmitate, polyoxyethylene-sorbitan monostearate, polyoxyethylene-sorbitan monotrioleate, and polyoxyethylene-sorbitan tristearate.

[0056] The pattern forming method provided by the present invention includes: forming a material layer on a substrate; applying the above-mentioned resist underlayer film composition on the material layer and performing heat treatment to form a resist underlayer film; forming a photoresist resist layer on the resist underlayer film; exposing and developing the photoresist resist layer to form a photoresist pattern; removing the resist underlayer film using the photoresist pattern as a mask to expose a portion of the material layer; and etching the exposed portion of the material layer.

[0057] In the present invention, the substrate may be a silicon wafer, a glass substrate or a polymer substrate.

[0058] In the present invention, the material layer is the material to be finally patterned, and can be a metal layer such as an aluminum layer or a copper layer, a semiconductor layer such as a silicon layer, or an insulating layer such as silicon dioxide or silicon nitride. The thickness of the material layer is not particularly limited and can be 50 to 500 nm.

[0059] In the present invention, the resist underlayer film is formed as follows: a resist underlayer film composition is applied to the material layer in the form of a solution by spin coating, followed by heating at 240-400°C for 50-600 seconds to obtain the resist underlayer film. The thickness of the resist underlayer film is not particularly limited and can be 80-500 nm. The resist underlayer film can be removed by dry etching using a mixture of CHF3 and CF4 gases.

[0060] In the present invention, the photoresist layer can be formed of, for example, ArF type, KrF type or EUV type photoresist.

[0061] In the present invention, the light source for exposing the photoresist layer may be, for example, ArF, KrF or EUV.

[0062] The main improvement of the pattern forming method provided by the present invention is that a new resist underlayer film composition is used to form the resist underlayer film, and the methods of forming the photoresist resist layer, exposing, developing, selectively removing part of the resist underlayer film, etching the exposed part of the material layer, etc. can all be the same as the prior art. Those skilled in the art are aware of this and will not be elaborated here.

[0063] The present invention will be described in detail below through specific examples. The examples of the embodiments are intended to explain the present invention and are not to be construed as limiting the present invention. Where specific techniques or conditions are not specified in the examples, the techniques or conditions described in the literature in this field or the product specifications are used. Where the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be obtained commercially.

[0064] Preparation Example 1 Preparation of Resist Underlayer Film Monomer 1-1a

[0065] At room temperature, 50 mL of toluene, 6.75 g (25 mmol) of 2-hydroxytriptycene, 1.53 g (51 mmol) of paraformaldehyde, and 2.33 g (25 mmol) of aniline were added to a 250 mL three-necked beaker equipped with a stirrer and a reflux condenser. The mixture was heated to 120°C under nitrogen protection, reacted at this temperature for 6 h, cooled to room temperature, and n-hexane was added. The precipitate was precipitated and filtered. The filter cake was dried at 60°C for 24 h to obtain the product, which is the resist underlayer film monomer 1-1a. The specific reaction process is shown in the following reaction formula (1). Nuclear magnetic resonance detection shows that the resist underlayer film monomer 1-1a indeed has the structure shown below.

[0066] The nuclear magnetic detection results of monomer 1-1a are 13C-NMR (400 MHz, DMSO): 93.0 (1C), 155.5 (1C), 149.6 (1C), 59.7 (1C), 141.6 (1C), 134.4 (1C), 145.7 (4C), 118.5 (1C), 112.6 (1C), 114.3 (2C), 130.5 (1C), 123.7 (4C), 129.6 (2C), 126.7 (4C), 121.9 (1C), 52.7 (2C).

[0067]

[0068] Preparation Example 2 Preparation of Resist Underlayer Film Monomer 1-2a

[0069] At room temperature, 50 mL of toluene, 7.16 g (25 mmol) of 9,10-dihydro-9,10[1',2']-benzanthracene-2,6-diol (CAS: 899445-49-9), 3.06 g (102 mmol) of paraformaldehyde, and 4.66 g (50 mmol) of aniline were added to a 250 mL three-necked beaker equipped with a stirrer and a reflux condenser. The mixture was heated to 120°C under nitrogen protection and reacted at this temperature for 6 h. The mixture was cooled to room temperature, and n-hexane was added to precipitate the precipitate, filtered, and the filter cake was dried at 60°C for 24 h to obtain the product, which is the resist lower layer film monomer 1-2a. The specific reaction process is shown in the following reaction formula (2). Nuclear magnetic resonance detection shows that the resist lower layer film monomer 1-2a indeed has the structure shown below.

[0070] The nuclear magnetic detection results of monomer 1-2a are 13C-NMR (400 MHz, DMSO): 93.0 (2C), 155.5 (2C), 149.6 (2C), 59.7 (2C), 118.5 (1C), 141.6 (1C), 134.4 (1C), 145.7 (2C), 118.5 (1C), 141.6 (1C), 134.4 (1C), 112.6 (1C), 114.3 (4C), 112.6 (1C), 130.5 (2C), 123.7 (2C), 129.6 (4C), 126.7 (2C), 121.9 (2C), 53.0 (2C).

[0071]

[0072] Preparation Example 3 Preparation of Resist Underlayer Film Monomer 1-3a

[0073] At room temperature, 50 mL of toluene, 7.56 g (25 mmol) of 2,6,14-trihydroxytriptycene, 4.59 g (153 mmol) of paraformaldehyde, and 6.98 g (75 mmol) of aniline were added to a 250 mL three-necked beaker equipped with a stirrer and a reflux condenser. The mixture was heated to 120°C under nitrogen protection and reacted at this temperature for 6 h. The mixture was cooled to room temperature, and n-hexane was added. The precipitate was precipitated and filtered. The filter cake was dried at 60°C for 24 h to obtain the product, which is the resist lower layer film monomer 1-3a. The specific reaction process is shown in the following reaction formula (3). Nuclear magnetic resonance detection shows that the resist lower layer film monomer 1-3a indeed has the structure shown below.

[0074] The nuclear magnetic detection results of monomer 1-3a are 13C-NMR (400 MHz, DMSO): 93.0 (3C), 155.5 (3C), 149.6 (3C), 59.7 (3C), 118.5 (1C), 141.6 (2C), 134.4 (2C), 118.5 (2C), 141.6 (1C), 134.4 (1C), 112.6 (2C), 114.3 (3C), 112.6 (1C), 130.5 (3C), 114.3 (3C), 129.6 (6C), 121.9 (3C), 53.3 (2C).

[0075]

[0076] Preparation Example 4 Preparation of Resist Underlayer Film Monomer 1-4a

[0077] A resist underlayer film monomer was prepared according to the method of Preparation Example 1, except that an equal molar amount of ethylamine was used instead of aniline. All other conditions were the same as those of Preparation Example 1, thereby preparing a resist underlayer film monomer 1-4a. The specific reaction process is shown in Reaction Formula (4). Nuclear magnetic resonance (NMR) analysis confirmed that the resist underlayer film monomer 1-4a indeed had the structure shown below.

[0078] The nuclear magnetic detection results of monomer 1-4a are 13C-NMR (400 MHz, DMSO): 84.9 (1C), 156.4 (1C), 52.8 (1C), 141.8 (1C), 134.3 (1C), 145.7 (4C), 119.2 (1C), 112.5 (1C), 131.4 (1C), 123.7 (4C), 126.7 (4C), 52.7 (2C), 47.9 (1C) 13.3 (1C).

[0079]

[0080] Preparation Example 5 Preparation of Resist Underlayer Film Monomer 1-5a

[0081] A resist underlayer film monomer was prepared according to the method of Preparation Example 1, except that an equal molar amount of pentylamine was used instead of aniline. All other conditions were the same as those of Preparation Example 1, thereby preparing resist underlayer film monomer 1-5a. The specific reaction process is shown in reaction formula (5). Nuclear magnetic resonance (NMR) analysis confirmed that resist underlayer film monomer 1-5a indeed had the structure shown below.

[0082] The nuclear magnetic detection results of monomer 1-5a are 13C-NMR (400 MHz, DMSO): 85.2 (1C), 156.4 (1C), 53.1 (1C), 141.8 (1C), 134.3 (1C), 145.7 (4C), 119.2 (1C), 112.5 (1C), 131.4 (1C), 123.7 (4C), 126.7 (4C), 52.7 (2C), 52.8 (1C), 28.0 (1C), 29.5 (1C), 22.4 (1C), 14.1 (1C).

[0083]

[0084] Preparation Example 6 Preparation of Aromatic Polymer 2-1a

[0085] In a 500 mL three-necked flask, 30.1 g (0.086 mol) of 4,4'-(9-fluorenylene)diphenol, 2.7 g (0.090 mol) of paraformaldehyde, and 1.5 g (0.009 mol) of p-toluenesulfonic acid were added, along with 200 g of tetralin. The mixture was reacted at 150°C for 12 hours under nitrogen. After the reaction, the reaction solution was cooled and diluted with 100 g of tetrahydrofuran. The diluted reaction solution was then poured into methanol to remove unreacted monomers and low-molecular-weight polymers. The mixture was filtered, and the filter cake was further washed twice with methanol. The mixture was then dried in a vacuum oven at 50°C for 12 hours to obtain the aromatic polymer represented by Formula 2-1a. Testing showed that the weight-average molecular weight of the polymer was 4600 g / mol and the polydispersity was 2.1.

[0086]

[0087] Preparation Example 7 Preparation of Aromatic Polymer 2-2a

[0088] An aromatic polymer was prepared according to the method of Preparation Example 6, except that the same molar amount of 1-hydroxypyrene was used instead of 4,4'-(9-fluorenylene)diphenol. The other conditions were the same as those in Preparation Example 6. Thus, an aromatic polymer represented by Formula 2-2a was prepared. After testing, the weight-average molecular weight of the polymer was 8500 g / mol, and the polydispersity was 1.9.

[0089]

[0090] Preparation Example 8 Preparation of Aromatic Polymer 2-3a

[0091] An aromatic polymer was prepared according to the method of Preparation Example 7, except that the same mole of 1-naphthaldehyde was used instead of paraformaldehyde. The other conditions were the same as those in Preparation Example 7, thereby preparing an aromatic polymer represented by Formula 2-3a. After testing, the weight-average molecular weight of the polymer was 9200 g / mol, and the polydispersity was 2.0.

[0092]

[0093] Examples and Comparative Examples

[0094] The resist underlayer film monomer, aromatic polymer, solvent, crosslinking agent, catalyst, and surfactant were uniformly mixed according to the ratios shown in Table 1 to obtain a resist underlayer film composition. The solvent was propylene glycol monomethyl ether acetate (PGMEA), the catalyst was p-toluenesulfonic acid, the surfactant was polyoxyethylene lauryl ether, and the crosslinking agent was a glycoluril compound having the following structure:

[0095]

[0096] Table 1 (content unit: weight parts)

[0097]

[0098] Test Case

[0099] 1. Scratch resistance test

[0100] The resist underlayer film compositions obtained in the examples and comparative examples were respectively coated on silicon wafers using a spin coating machine and treated at 350°C for 120s to form resist underlayer films. The film thickness was measured using a film thickness meter manufactured by KMAC. The resist underlayer film was then etched using a CHF3 / CF4 mixed gas. The etching conditions were as follows: a processing chamber pressure of 40 Pa, a PF power of 1300 W, a CHF3 gas flow rate of 30 mL / min, a CF4 gas flow rate of 30 mL / min, an Ar gas flow rate of 100 mL / min, and an etching time of 30s. After etching, the film thickness was measured again, and the etching rate was calculated using Formula 1. The results are shown in Table 2.

[0101] Calculation formula 1: Etching rate = (initial thickness of the resist underlayer film - thickness of the resist underlayer film after etching) / etching time.

[0102] 2. Heat resistance test

[0103] The resist underlayer film composition solutions of the examples and comparative examples were each applied to a silicon wafer using a spin coater and fired at 350°C for 180 seconds to form resist underlayer films. These resist underlayer films were scraped from the silicon wafer to obtain powders. Using a thermogravimetric analyzer (TGA) under a nitrogen atmosphere, the weight loss of each powder was measured by heating from 40°C to 400°C. The mass loss rate was calculated using Equation 2. The results are shown in Table 2.

[0104] Calculation formula 2: Mass loss rate = [(initial mass - mass at 400°C) / initial mass] × 100%

[0105] 3. Contact angle test

[0106] The contact angle of the resist lower layer film was measured using a contact angle meter (KRUSS, DSA100L). The results are shown in Table 2.

[0107] 4. Photoresist pattern performance evaluation

[0108] First, a resist underlayer film composition was spin-coated onto a silicon wafer and heated at 250°C for 60 seconds to form a resist underlayer film. A positive photoresist (PR-1) was then spin-coated onto the resist underlayer film and heated at 100°C for 90 seconds to form a photoresist film. Exposure was performed using an ArF exposure system (NIKON S305B), followed by heating at 110°C for 90 seconds (PEB), and development was performed with a 2.38% aqueous solution of tetramethylammonium hydroxide to form a positive photoresist pattern with a line width of 0.13 μm. The resulting photoresist pattern was measured for dimensions using a Hitachi High-Technologies Corporation electron microscope (CG6300), pattern collapse and cross-sectional shape using a Hitachi High-Technologies Corporation electron microscope (S4700), and line width roughness (LWR) was measured using a Hitachi High-Technologies Corporation electron microscope (CG4000). The test results are shown in Table 3.

[0109] The PR-1 polymer is composed of 1 part by weight of polymer W1, 0.05 parts by weight of photoacid generator PAG1, 0.01 parts by weight of quencher Q1, and 2.5 parts by weight of solvent PGMEA. Polymer W1 has the structure shown in formula (I), with m:n ratio of 0.4:0.6, molecular weight Mw of 8800 g / mol, and PDI of 1.81. Photoacid generator PAG1 has the structure shown in formula (II). Quencher Q1 has the structure shown in formula (III).

[0110]

[0111] Table 2

[0112]

[0113] Table 3

[0114] project Resist underlayer film ArF photoresist Pattern shape after development Pattern collapse LWR Example 1 Film1 PR-1 Vertical shape No collapse 2.0 Example 2 Film2 PR-1 Vertical shape No collapse 2.0 Example 3 Film3 PR-1 Vertical shape No collapse 1.9 Example 4 Film4 PR-1 Vertical shape No collapse 1.9 Example 5 Film5 PR-1 Vertical shape No collapse 1.9 Example 4 Film6 PR-1 Vertical shape No collapse 1.8 Example 5 Film7 PR-1 Vertical shape No collapse 1.8 Comparative Example 1 Film8 PR-1 Vertical shape have 2.3

[0115] It can be seen from the results in Table 2 and Table 3 that compared with Comparative Example 1, the resist underlayer film composition provided by the present invention has high etching resistance and heat resistance, and the resist underlayer film provided by the present invention has a larger contact angle, and its surface has good hydrophobicity and good adhesion to the photoresist surface. The line width roughness (LWR) of the photoresist pattern after development is small, the pattern shape is good, and there is no collapse.

[0116] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. A resist underlayer film monomer, characterized in that: The resist underlayer film monomer has a structure as shown in formula (1): In formula (1), R1 is a C1-C6 alkyl group or a C6-C 30 R2 and R3 are each independently a hydrogen atom, a hydroxyl group, a C1-C 10 Alkyl, C3~C 10 The monocyclic or polycyclic unsaturated group or R2 and R3 together with the benzene ring to which they are connected form an unsubstituted or C6-C 30 The benzoxazine structure is substituted with an aromatic group, R4 and R5 are each independently a hydrogen atom, a hydroxyl group, a C1 to C2 group containing or not containing heteroatoms 10 Alkyl, C3~C 10 The monocyclic or polycyclic unsaturated group or R4 and R5 together with the benzene ring to which they are connected form an unsubstituted or C6-C 30 Aryl-substituted benzoxazine structure.

2. The resist underlayer film monomer according to claim 1, wherein The resist underlayer film monomer is selected from at least one of the compounds having the structures represented by formula (1-1), formula (1-2), and formula (1-3): In formula (1-1), formula (1-2) and formula (1-3), R 11 ~R 16 Each independently is a C1 to C6 alkyl group or a C6 to C 30 of aromatic groups.

3. A resist underlayer film composition, characterized in that The resist underlayer film composition contains the resist underlayer film monomer according to claim 1 or 2, an aromatic polymer, and a solvent.

4. The resist underlayer film composition according to claim 3, wherein The mass ratio of the resist underlayer film monomer to the aromatic polymer is 1:(0.1-10); The total mass content of the resist underlayer film monomer and the aromatic polymer is 10 to 25 wt % based on the total mass of the resist underlayer film composition.

5. The resist underlayer film composition according to claim 3, wherein The aromatic polymer contains structural units represented by formula (2) and / or formula (3): In formula (2) and formula (3), Ar1 and Ar2 are each independently substituted or unsubstituted C6 to C 30 R6 is a hydrogen atom or a C6~C 16 wherein n is an integer of 1 to 200.

6. The resist underlayer film composition according to claim 3, wherein The Ar1 and Ar2 are each independently selected from at least one of the structures represented by formula (2-1), formula (2-2), and formula (2-3): In formula (2-1), formula (2-2) and formula (2-3), It represents the bond between the Ar1 or Ar2 group and other structural units.

7. The resist underlayer film composition according to claim 3, wherein The aromatic polymer preferably has a weight average molecular weight of 500 to 6000 g / mol and a polydispersity of 1.5 to 2.

5.

8. The resist underlayer film composition according to claim 3, wherein The solvent is selected from at least one of propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, cyclohexanone and ethyl lactate; The resist underlayer film composition further contains a catalyst and / or a surfactant; The catalyst is selected from at least one of acidic compounds; The surfactant is selected from at least one of polyoxyethylene alkyl ethers, polyoxyethylene alkyl aryl ethers, sorbitan fatty acid esters and polyoxyethylene sorbitan fatty acid esters.

9. A resist underlayer film, characterized in that: A resist underlayer film is obtained by applying the resist underlayer film composition according to any one of claims 3 to 8 onto a substrate and subjecting the substrate to heat treatment.

10. A pattern forming method, characterized in that: The method comprises: forming a material layer on a substrate; applying the resist underlayer film composition described in any one of claims 3 to 8 on the material layer and performing heat treatment to form a resist underlayer film; forming a photoresist layer on the resist underlayer film; exposing and developing the photoresist layer to form a photoresist pattern; removing the resist underlayer film using the photoresist pattern as a mask to expose a portion of the material layer; and etching the exposed portion of the material layer.

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