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

Abstract

The invention belongs to the field of photoetching, and particularly 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 represented by formula (1), an aromatic polymer, and a solvent. The key of the invention lies in that the resist underlayer film monomer containing the triptycene benzoxazine structure is introduced, on one hand, the triptycene structure with high carbon content can improve the etching resistance of the resist underlayer film, and on the other hand, the resist underlayer film monomer containing the triptycene benzoxazine structure has good structural stability; the resist underlayer film formed by the method can be crosslinked under a heating condition, so that the formed resist underlayer film has improved heat resistance and etching resistance, the hydrophilicity of the resist underlayer film is reduced, the adhesion of the resist underlayer film to the surface of the photoresist is improved, the developed photoresist pattern is not easy to collapse, and the yield of the photoresist is improved. The line width roughness (LWR) of the photoresist pattern is small, and the formed pattern effect is good. # imgabs0 #

Description

Technical Field

[0001] The present invention belongs to the field of lithography, and particularly relates to a monomer for an underlayer film of a resist, an underlayer film composition of a resist, and a pattern forming method. Background Art

[0002] In recent years, with the development requirements of high integration and high speed of semiconductor elements, people are seeking methods to further improve the fineness of lithographic patterns. Among them, various technical developments have been carried out on the light sources used for how to perform fine and high-precision pattern processing. As the light source used when forming a lithographic pattern, in the part with low integration, exposure is widely performed using the g-line (436 nm) or i-line (365 nm) of a mercury lamp as the light source; in the part with high integration and the need for fineness, the use of shorter wavelength KrF excimer laser (248 nm), ArF excimer laser (193 nm) as the exposure light source has also been put into practical use; in the most advanced era where further fineness of the pattern is required, the practical use of exposure using extreme ultraviolet light (EUV, 13.5 nm) is not far off.

[0003] Lithography 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 using the photoresist pattern as a mask to etch the material layer. Currently, according to the requirement of the smaller size of the pattern to be formed in the future, it is difficult to provide a fine pattern with a clear profile only through the above typical lithography technology. Therefore, an intermediate layer called a hard mask or an underlayer film of a resist can be formed between the material layer and the photoresist layer to provide a fine pattern, and the intermediate layer is used to transfer the fine pattern of the photoresist to the material layer through a selective etching process. Therefore, the underlayer film of a resist needs to have characteristics such as heat resistance and etching resistance to ensure its good tolerance during multiple etching processes, which is beneficial to the transfer and formation of fine patterns. Currently, the existing underlayer films of resists have problems of poor tolerance and poor adhesion to the photoresist layer, which affect the formation effect of the photoresist pattern. Summary of the Invention

[0004] An object of the present invention is to provide a monomer for an underlayer film of a resist in view of the problems that the underlayer film of a resist prepared according to the prior art has poor tolerance and poor adhesion to the photoresist layer, which affect the formation effect of the photoresist pattern. The underlayer film composition of a resist containing this monomer can not only improve the heat resistance and etching resistance of the underlayer film of a resist, but also has good adhesion to the photoresist layer, which is beneficial to obtaining a fine lithographic pattern with good formation effect and no collapse.

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

[0006]

[0007] In formula (1), R1 is an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to C 30 carbon atoms, and R2 and R3 are each independently a hydrogen atom, a hydroxyl group, an alkyl group having 1 to C 10 carbon atoms, a monocyclic or polycyclic unsaturated group having 3 to C 10 carbon atoms with or without heteroatoms, or R2 and R3 together with the benzene ring to which they are attached form an unsubstituted or C6-C 30 carbon atom-substituted benzoxazine structure, and R4 and R5 are each independently a hydrogen atom, a hydroxyl group, an alkyl group having 1 to C 10 carbon atoms with or without heteroatoms, a monocyclic or polycyclic unsaturated group having 3 to C 10 carbon atoms with or without heteroatoms, or R2 and R3 together with the benzene ring to which they are attached form an unsubstituted or C6-C 30 carbon atom-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 shown in 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 are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to C 30 carbon atoms.

[0012] In a preferred embodiment, R 11 ~R 16 are each independently an aryl group having 6 to C 30 carbon atoms.

[0013] Second, the present invention provides a resist underlayer film composition. The resist underlayer film composition contains the above-mentioned 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 to 10).

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

[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 a substituted or unsubstituted C6-C 30 aryl group, R6 is a hydrogen atom or a C6-C 16 aryl group, and n is an integer from 1 to 200.

[0019] In a preferred embodiment, 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):

[0020]

[0021] In formula (2-1), formula (2-2), and formula (2-3), represents a bond by which the Ar1 or Ar2 group is bonded to 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 selected from at least one of polyoxyethylene alkyl ethers, polyoxyethylene alkyl aryl ethers, sorbitan fatty acid esters, and polyoxyethylene sorbitan fatty acid esters.

[0027] Thirdly, the present invention provides a resist underlayer film, which is obtained by coating the above resist underlayer film composition on a substrate and then performing heat treatment.

[0028] Fourth aspect, the present invention also provides a pattern forming method. The method includes: forming a material layer on a substrate; applying the above-mentioned underlayer resist composition on the material layer and performing heat treatment to form an underlayer resist film; forming a photoresist layer on the underlayer resist film; exposing and developing the photoresist layer to form a photoresist pattern; using the photoresist pattern as a mask to remove the underlayer resist film to expose a part of the material layer; etching the exposed part of the material layer.

[0029] Beneficial effects: The underlayer resist 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 underlayer resist film. On the other hand, the underlayer resist film monomer containing the triptycene benzoxazine structure has good structural stability and can undergo self-polymerization or polymerization with aromatic polymers under heating conditions, so that the underlayer resist film formed by the composition containing this underlayer resist film monomer has improved heat resistance and etching resistance. At the same time, introducing the underlayer resist film monomer with this specific structure also reduces the hydrophilicity of the underlayer resist film and improves its adhesion to the surface of the photoresist, making the developed photoresist pattern not easy to collapse, with a smaller line width roughness (LWR) of the photoresist pattern and a good pattern forming effect, and can well meet the application requirements of fine photoresist patterns. Detailed implementation mode

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

[0031]

[0032] In formula (1), R1 is an alkyl group with 1 to 6 carbon atoms or an aryl group with 6 to C 30 carbon atoms, R2 and R3 are each independently a hydrogen atom, a hydroxyl group, an alkyl group with 1 to C 10 carbon atoms, a monocyclic or polycyclic unsaturated group with or without heteroatoms and having 3 to C 10 carbon atoms, or R2 and R3 together with the benzene ring to which they are attached form an unsubstituted or aryl group-substituted benzoxazine structure with 6 to C 30 carbon atoms, R4 and R5 are each independently a hydrogen atom, a hydroxyl group, an alkyl group with 1 to C 10 carbon atoms with or without heteroatoms, a monocyclic or polycyclic unsaturated group with or without heteroatoms and having 3 to C 10 carbon atoms, or R2 and R3 together with the benzene ring to which they are attached form an unsubstituted or aryl group-substituted benzoxazine structure with 6 to C 30 carbon atoms. The heteroatom is selected from at least one of an oxygen atom, a nitrogen atom, and a sulfur atom.

[0033] Among them, specific examples of the C1-C6 alkyl group include, but are not limited to: 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, at least one of them. C6-C 30 Specific examples of the aryl group include, but are not limited to: phenyl, naphthyl, anthryl, phenanthryl, pyrenyl, benzopyrenyl, diphenylfluorenyl, biphenyl, at least one of them. C1-C 10 Specific examples of the C1-C alkyl group include, but are not limited to: 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, n-decyl, at least one of them. C3-C containing a heteroatom 10 Specific examples of the monocyclic or polycyclic unsaturated group include, but are not limited to: pyridyl, pyrrolyl, furyl, thienyl, indolyl, at least one of them. C3-C without a heteroatom 10 Specific examples of the monocyclic or polycyclic unsaturated group include, but are not limited to: cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, cyclononenyl, cyclodecenyl, phenyl, naphthyl, at least one of them.

[0034] In the present invention, the resist underlayer film monomer is preferably at least one selected from the compounds having the structures shown in 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 are each independently preferably a C1-C6 alkyl group or a C6-C 30 aryl group, more preferably a C6-C 30aryl. Among them, the C1-C6 alkyl group and C6-C 30 Specific examples of the aryl group are as described above and will not be elaborated here one by one.

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

[0038] The resist lower layer film monomer provided by the present invention contains a benzoxazine structure. Under the action of heating, the following ring-opening polymerization reaction will occur to generate a network structure containing a nitrogen-containing phenolic resin-like substance. During the curing process, no small molecules are released and the volume shrinkage rate is approximately zero, without the worry of polluting the resist lower layer film and equipment.

[0039]

[0040] In the present invention, the mass ratio of the resist lower layer 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 lower layer 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. At this time, it is more conducive to forming a resist lower layer film with a uniform film thickness.

[0041] In the present invention, based on the total mass of the resist lower layer film composition, the sum of the mass contents of the resist lower layer film monomer and the aromatic polymer is preferably 10-25 wt%, such as 10 wt%, 12 wt%, 14 wt%, 18 wt%, 20 wt%, 22 wt%, 25 wt% or any value therebetween. At this time, it is more conducive to forming a resist lower layer film with 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 a substituted or unsubstituted C6-C 30 aryl, R6 is a hydrogen atom or a C6-C 16 aryl, and n is an integer from 1 to 200. Among them, the specific examples of the C6-C 30 aryl are as described above. C6-C 16Specific examples of the aryl group include, but are not limited to, at least one of phenyl, naphthyl, anthryl, 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 may be a polymer containing structural units represented by formula (2) and / or formula (3). It can be obtained by purchasing commercially, or can be obtained after preparation based on existing disclosed preparation methods or preparation principles.

[0046] In a specific embodiment, each of Ar1 and Ar2 is independently preferably 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), represents the bond by which the Ar1 or Ar2 group is bonded to 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: subjecting an aromatic phenolic compound containing Ar1 and an aldehyde compound containing R6 to a polycondensation reaction under the condition of an acidic catalyst, and the resulting reaction product is an aromatic polymer containing a structural unit represented by formula (2). Method 2 preferably includes the following steps: subjecting an aromatic phenolic compound containing Ar1 or Ar2 and formaldehyde or paraformaldehyde to a polycondensation reaction under the condition of an acidic catalyst, and the resulting reaction product is an aromatic polymer containing a structural unit represented by formula (3).

[0050] In a specific embodiment, specific examples of the aromatic phenolic compound containing Ar1 and the aromatic phenolic compound containing Ar2 each 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-fluorenylidene)diphenol. Specific examples of the aldehyde compound containing R6 include but are not limited to at least one of benzaldehyde, naphthaldehyde, anthracenealdehyde, and pyrenealdehyde. The acidic catalyst can be an organic acid or an inorganic acid. Among them, the inorganic acid can be selected from at least one of sulfuric acid, phosphoric acid, perchloric acid, and nitric acid, and the organic acid can be selected from at least one of p-toluenesulfonic acid, formic acid, and oxalic acid. The polycondensation reaction is usually carried out in a solvent. The solvent can be various existing inert liquids that do not hinder the progress of the polycondensation reaction. Specific examples thereof include but are not limited to at least one of tetralin, tetrahydrofuran, propylene glycol monomethyl ether, and propylene glycol monomethyl ether. The conditions of the polycondensation reaction can be selected according to existing methods for preparing aromatic polymers. Preferably, the polycondensation reaction is carried out in an inert gas atmosphere, the reaction temperature is 100-200 °C, and the reaction time is selected according to the actual reaction temperature and molecular weight, usually 2-20 h.

[0051] In the present invention, the weight average molecular weight (Mw) of the aromatic polymer is preferably 500-6000 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 between them; the polydispersity is preferably 1.5-2.5, such as 1.5, 1.8, 2.0, 2.2, 2.5, or any value between them.

[0052] In the present invention, the solvent can be a kind of liquid substance that has sufficient solubility or dispersibility for the underlayer resist monomer and the aromatic polymer. 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 underlayer resist composition preferably further contains a catalyst and / or a surfactant.

[0054] In the present invention, the catalyst can be a kind of substance that promotes the crosslinking reaction. Preferably, it is an acidic substance. 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 improving the film-forming quality of the underlayer film of the resist and reducing the occurrence of defects such as pinholes and stripes. Specific examples of the surfactant include, but are not limited to: polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, polyoxyethylene oleyl ether and other polyoxyethylene alkyl ethers, polyoxyethylene octylphenol ether, polyoxyethylene nonylphenol ether and other polyoxyethylene alkylaryl ethers, sorbitan monopalmitate, sorbitan monostearate, sorbitan monolaurate, sorbitan monooleate, sorbitan trioleate, sorbitan tristearate and other sorbitan fatty acid esters, polyoxyethylene-sorbitan monolaurate, polyoxyethylene-sorbitan monopalmitate, polyoxyethylene-sorbitan monostearate, polyoxyethylene-sorbitan monooleate, polyoxyethylene-sorbitan tristearate and other polyoxyethylene sorbitan fatty acid esters, at least one of which.

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

[0057] In the present invention, the substrate can 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 formation process of the underlayer film of the resist is specifically as follows: the underlayer film composition of the resist is coated on the material layer in the form of a solution by spin coating, and then heated at 240 to 400 °C for 50 to 600 s to obtain the underlayer film of the resist. The thickness of the underlayer film of the resist is not particularly limited and can be 80 to 500 nm. The underlayer film of the resist can be removed by dry etching with a mixed gas of CHF3 and CF4.

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

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

[0062] The main improvement of the pattern formation method provided by the present invention lies in the use of a new underlayer resist composition to form an underlayer resist film, while the formation, exposure, development of the photoresist layer, selective removal of part of the underlayer resist film, etching of the exposed part of the material layer, etc. can all be the same as those in the prior art, which are well-known to those skilled in the art and will not be elaborated here.

[0063] The present invention will be described in detail below through specific examples. The examples are intended to explain the present invention and should not be construed as limiting the present invention. For those without specific technologies or conditions noted in the examples, the technologies or conditions described in the literature in the field or according to the product specifications shall be followed. For reagents or instruments without the manufacturer noted, they are all conventional products that can be obtained through commercial purchase.

[0064] Preparation Example 1 Preparation of Underlayer Resist 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 flask equipped with a stirrer and a reflux condenser. The temperature was raised to 120 °C under nitrogen protection and reacted at this temperature for 6 h. After cooling to room temperature, n-hexane was added, and a precipitate was formed and filtered. The filter cake was dried at 60 °C for 24 h to obtain the product, which is the underlayer resist monomer 1-1a. Among them, the specific reaction process is shown in Reaction Formula (1) below. After nuclear magnetic detection, the underlayer resist monomer 1-1a indeed has the following structure.

[0066] Nuclear magnetic detection results of monomer 1-1a 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 Underlayer Resist 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 flask 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. After cooling to room temperature, n-hexane was added to precipitate a solid, which was then filtered. The filter cake was dried at 60 °C for 24 h to obtain the product, which is the monomer 1-2a of the lower layer film of the resist. The specific reaction process is shown in Reaction Formula (2) below. Through NMR detection, the monomer 1-2a of the lower layer film of the resist indeed has the structure shown below.

[0070] 13C-NMR (400 MHz, DMSO) of the monomer 1-2a: 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 the monomer 1-3a of the lower layer film of the resist

[0073] At room temperature, 50 mL of toluene, 7.56 g (25 mmol) of 2,6,14-trihydroxytriphenylene, 4.59 g (153 mmol) of paraformaldehyde, and 6.98 g (75 mmol) of aniline were added to a 250 mL three-necked flask 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. After cooling to room temperature, n-hexane was added to precipitate a solid, which was then filtered. The filter cake was dried at 60 °C for 24 h to obtain the product, which is the monomer 1-3a of the lower layer film of the resist. The specific reaction process is shown in Reaction Formula (3) below. Through NMR detection, the monomer 1-3a of the lower layer film of the resist indeed has the structure shown below.

[0074] The nuclear magnetic resonance 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] The resist lower film monomer was prepared according to the method of Preparation Example 1, except that the same mole of ethylamine was used instead of aniline, and the other conditions were the same as those of Preparation Example 1, thereby preparing the resist lower film monomer 1-4a. The specific reaction process is shown in the following reaction formula (4). After nuclear magnetic resonance detection, the resist lower film monomer 1-4a indeed has the structure shown below.

[0078] The nuclear magnetic resonance 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] The resist lower film monomer was prepared according to the method of Preparation Example 1, except that the same mole of pentylamine was used instead of aniline, and the other conditions were the same as those of Preparation Example 1, thereby preparing the resist lower film monomer 1-5a. The specific reaction process is shown in the following reaction formula (5). After nuclear magnetic resonance detection, the resist lower film monomer 1-5a indeed has the structure shown below.

[0082] 13C-NMR (400 MHz, DMSO) results of monomer 1-5a: 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-fluorenylidene)diphenol, 2.7 g (0.090 mol) of paraformaldehyde and 1.5 g (0.009 mol) of p-toluenesulfonic acid were added, and 200 g of tetralin was added. The reaction was carried out at 150 °C for 12 h under nitrogen protection. After the reaction was completed, the reaction solution was cooled, diluted with 100 g of tetrahydrofuran, and then the diluted reaction solution was poured into methanol to remove unreacted monomers and low molecular weight polymers. The mixture was filtered, and the filter cake was further washed with methanol twice and then dried in a vacuum oven at 50 °C for 12 h to obtain the aromatic polymer shown in Formula 2-1a. After testing, the weight average molecular weight of this polymer was 4600 g / mol and the polydispersity was 2.1.

[0086]

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

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

[0089]

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

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

[0092]

[0093] Examples and Comparative Examples

[0094] The resist underlayer film monomers, aromatic polymer, solvent, crosslinking agent, catalyst, and surfactant were mixed evenly according to the formulation ratios in Table 1 to obtain a resist underlayer film composition. Among them, 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 with the following structure:

[0095]

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

[0097]

[0098] Test Examples

[0099] 1. Etch Resistance Test

[0100] The resist underlayer film compositions obtained in the examples and comparative examples were respectively coated on silicon wafers using a spin coater and treated at 350 °C for 120 s to form a resist underlayer film. The film thickness was measured using a thin film thickness measuring instrument manufactured by KMAC. Then, the resist underlayer film was etched using a CHF3 / CF4 mixed gas. The specific etching conditions were as follows: the pressure in the processing chamber was 40 Pa, the PF power was 1300 W, the flow rate of CHF3 gas was 30 mL / min, the flow rate of CF4 gas was 30 mL / min, the flow rate of Ar gas was 100 mL / min, and the etching time was 30 s. After the etching was completed, the film thickness was measured again, and the etching rate was calculated using Calculation Formula 1. The obtained 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 respectively coated on silicon wafers using a spin coater, and baked at 350 °C for 180 s to form resist underlayer films. These resist underlayer films were scraped off from the silicon wafers to obtain powders. Using a thermogravimetric analyzer (TGA), the weight loss of each of the above powders was measured while heating from 40 °C to 400 °C in a nitrogen atmosphere, and the mass loss rate was calculated according to the following calculation formula 2. The obtained 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 measurement

[0106] The contact angle of the resist underlayer film was detected using a contact angle measuring instrument (KRUSS, DSA100L). The obtained results are shown in Table 2.

[0107] 4. Evaluation of photoresist pattern performance

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

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

[0110]

[0111] Table 2

[0112]

[0113] Table 3

[0114] Project Underlying Resist Film ArF Photoresist Pattern Shape after Development Pattern Collapse Condition 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 Yes 2.3

[0115] It can be seen from the results of Table 2 and Table 3 that, compared with Comparative Example 1, the underlayer film composition of the present invention has high etching resistance and heat resistance, and the underlayer film of the present invention has a large contact angle, indicating that it has good hydrophobic properties, good adhesion to the surface of the photoresist, a small line width roughness (LWR) of the photoresist pattern after development, a good pattern shape, and no collapse.

[0116] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A resist underlayer film monomer, characterized in that, The resist underlayer film monomer has a structure represented by the following formula (1): In formula (1), R1 is an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 30 carbon atoms, R2 and R3 are each independently a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms, a monocyclic or polycyclic unsaturated group with or without heteroatoms having 3 to 10 carbon atoms, or R2 and R3 together with the benzene ring to which they are attached form an unsubstituted or C6-C 30 aryl-substituted benzoxazine structure, R4 and R5 are each independently a hydrogen atom, a hydroxyl group, an alkyl group with or without heteroatoms having 1 to 10 carbon atoms, a monocyclic or polycyclic unsaturated group with or without heteroatoms having 3 to 10 carbon atoms, or R2 and R3 together with the benzene ring to which they are attached 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 compounds having 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 are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 30 carbon atoms; Preferably, R 11 ~R 16 are each independently an aryl group having 6 to 30 carbon atoms.

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); Preferably, based on the total mass of the resist underlayer film composition, the sum of the mass contents of the resist underlayer film monomer and the aromatic polymer is 10 - 25 wt%.

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 a substituted or unsubstituted aryl group having 6 to C 30 , R6 is a hydrogen atom or an aryl group having 6 to C 16 , and n is an integer from 1 to 200.

6. The resist underlayer film composition according to claim 3, wherein Each of Ar1 and Ar2 is 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), represents a bond by which the Ar1 or Ar2 group is bonded to other structural units.

7. The resist underlayer film composition according to claim 3, wherein The weight-average molecular weight of the aromatic polymer is preferably 500 - 6000 g / mol, and the polydispersity is 1.5 - 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; Preferably, the resist underlayer film composition further contains a catalyst and / or a surfactant; Preferably, the catalyst is selected from at least one of acidic compounds; Preferably, 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, The resist underlayer film is obtained by coating the resist underlayer film composition according to any one of claims 3 - 8 on a substrate and then performing heat treatment.

10. A pattern forming method, characterized in that, The method includes: forming a material layer on a substrate; applying the resist underlayer film composition according to any one of claims 3 - 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; using the photoresist pattern as a mask to remove a part of the underlayer film of the resist layer to expose a part of the material layer; etching the exposed part of the material layer.

Images