1. A bottom anti-reflective film resin, characterized in that the bottom anti-reflective film resin comprises a fluorine-containing diester-based structural unit represented by formula (1) and optionally a fluorine-free diester-based structural unit represented by formula (2);

in the formula (1), Ar represents a benzene ring or a naphthalene ring, and n represents an integer of 1-6; in the formula (2), Ar' represents a benzene ring or a naphthalene ring; the weight average molecular weight Mw of the bottom anti-reflection film resin is 1000-100000; the proportion of the fluorine-containing diester-based structural unit in a bottom anti-reflection film resin molecular chain is more than 30 wt%, and the proportion of the fluorine-free diester-based structural unit in the bottom anti-reflection film resin molecular chain is 0-20 wt%.

2. The bottom anti-reflective film resin according to claim 1, wherein the fluorine-containing diester-based structural units account for 35 to 60 wt% of the molecular chain of the bottom anti-reflective film resin, and the fluorine-free diester-based structural units account for 0 to 15 wt% of the molecular chain of the bottom anti-reflective film resin.

3. The bottom antireflective film resin of claim 1, further comprising an alcohol-based structural unit derived from a polyol monomer represented by formula (3) or a polyepoxy monomer represented by formula (4);

HO-x-OH formula (3),

in the formulae (3) and (4), X represents C₁～C₆A substituted or unsubstituted straight or branched hydrocarbon group, C₆～C₁₀A substituted or unsubstituted alicyclic hydrocarbon group of (C)₆～C₁₀The substituted or unsubstituted aromatic group or the heterocyclic divalent group comprises 1-3 nitrogen atoms, and at least one substituent is optionally included on the straight-chain alkyl group, the branched-chain alkyl group, the alicyclic alkyl group, the aromatic group and the heterocyclic divalent group.

4. The bottom anti-reflection film resin according to any one of claims 1 to 3, wherein the bottom anti-reflection film resin is produced by polymerizing a diester-based compound with a polyol monomer or a polyepoxy monomer, the polyol monomer having a structure represented by formula (3), the polyepoxy monomer having a structure represented by formula (4), the diester-based compound comprising a fluorine-containing diester-based monomer having a structural unit represented by formula (5) and optionally a fluorine-free diester-based monomer having a structural unit represented by formula (6);

HO-x-OH formula (3),

in the formulae (3) and (4), X represents C₁～C₆A substituted or unsubstituted straight or branched hydrocarbon group, C₆～C₁₀A substituted or unsubstituted alicyclic hydrocarbon group of (C)₆～C₁₀The substituted or unsubstituted aromatic group or the heterocyclic divalent group comprises 1-3 nitrogen atoms, and at least one substituent is optionally included on the straight-chain alkyl group, the branched-chain alkyl group, the alicyclic alkyl group, the aromatic group and the heterocyclic divalent group; in the formula (5), Ar represents a benzene ring or a naphthalene ring, and n and m independently represent an integer of 1-6; in the formula (6), Ar' represents a benzene ring or a naphthalene ring, and m represents an integer of 1-6.

5. The bottom antireflective film resin of claim 4 wherein the polyol monomer is selected from at least one of the following formulas:

6. the bottom antireflective film resin of claim 4 wherein the multi-epoxy monomer is selected from at least one of the following formulas:

7. a bottom anti-reflective film composition comprising the bottom anti-reflective film resin according to any one of claims 1 to 6 and a solvent.

8. The bottom anti-reflective film composition according to claim 7, wherein the bottom anti-reflective film resin is contained in an amount of 0.5 to 15 wt% based on the total weight of the bottom anti-reflective film composition.

9. The bottom antireflective film composition of claim 7, further comprising at least one of a crosslinker, a catalyst, and a surfactant.

10. A pattern forming method, characterized by comprising the steps of:

forming a material layer on a substrate;

applying the bottom anti-reflective film composition according to any one of claims 7 to 9 on a material layer and performing a heat treatment to form a bottom anti-reflective film;

forming a photoresist resist layer on the bottom anti-reflection film;

exposing and developing the photoresist resist layer to form a photoresist pattern;

selectively removing a portion of the bottom anti-reflection film using the photoresist pattern to expose a portion of the material layer;

the exposed portions of the material layer are etched.

Background

In semiconductor manufacturing, microfabrication has been conventionally achieved by photolithography of a photoresist. With the increasing demand for the resolution of the photoresist, the exposure wavelength of the photoresist is continuously shortened, and the ultraviolet spectrum shifts to the following directions: g line (436nm) → I line (365nm) → KrF (248nm) → ArF (193nm) → F₂(157nm) → extreme ultraviolet EUV. In the process of 248nm and 193nm semiconductor photoetching technology, the interference Effect of reflected light and incident light of metal wires is more obvious, a Standing Wave Effect (Standing Wave Effect) is formed in photoresist, the problem of inconsistent line width is caused by the reflection Effect of bottom metal wires after gluing and exposure, interference patterns are caused by multiple reflections of light waves on the surface of the photoresist, the photoresist cannot be uniformly exposed, and wavy saw-tooth-shaped loss occurs on the side wall of the pattern, so that the difference between the line width and the designed size cannot be controlled. These problems eventually cause short circuits and open circuits in the lines and ultimately affect the yield of the lithographic process.

The provision of a bottom anti-reflective coating (BARC) under the photoresist is the best option to solve the above problems. The bottom anti-reflection film is a bottom anti-reflection film which is added between the photoresist and the substrate and can effectively eliminate light reflection to form interference standing waves. The bottom antireflection film can increase the exposure energy range and the focal length, reduce the influence of the geometrical structure difference of a matrix on the uniformity of a key size, reduce a circular notch caused by scattering of reflected light, and relieve the swinging curve effect and the notch effect caused by different thicknesses of photoresist due to the configuration of the matrix.

The bottom anti-reflective film composition forming the bottom anti-reflective film generally includes a specific light absorbing group having a high absorption ability for light in a photosensitive characteristic wavelength region of a photosensitive component of a photoresist layer provided on the bottom anti-reflective film, thereby preventing standing waves generated by reflection from a substrate. For light of 248nm wavelength, a typical light absorbing group is anthracene or naphthalene; for light of 193nm wavelength, a common light-absorbing group is benzene or naphthalene. However, for 193nm immersion lithography, BARCs with high absorbance (k) values are suitable for incident wave reflections with small projection lens opening Numbers (NA), but BARCs with low absorbance values are more effective as the projection lens opening numbers increase. Furthermore, a decrease in the absorbance value also causes a significant decrease in the refractive index (n).

Disclosure of Invention

The invention aims to overcome the defect of high absorbance of the prior bottom anti-reflection film containing benzene or naphthalene, and provides a bottom anti-reflection film resin, a composition and a pattern forming method which can reduce the absorbance on the basis of not influencing the refractive index basically.

Specifically, the invention provides a bottom anti-reflection film resin, which comprises a fluorine-containing diester-based structural unit shown as a formula (1) and an optional fluorine-free diester-based structural unit shown as a formula (2);

in the formula (1), Ar represents a benzene ring or a naphthalene ring, and n represents an integer of 1-6; in the formula (2), Ar' represents a benzene ring or a naphthalene ring; the weight average molecular weight Mw of the bottom anti-reflection film resin is 1000-100000; the proportion of the fluorine-containing diester-based structural unit in a bottom anti-reflection film resin molecular chain is more than 30 wt%, and the proportion of the fluorine-free diester-based structural unit in the bottom anti-reflection film resin molecular chain is 0-20 wt%.

Further, the proportion of the fluorine-containing diester-based structural unit in the molecular chain of the bottom anti-reflection film resin is 35-60 wt%, and the proportion of the fluorine-free diester-based structural unit in the molecular chain of the bottom anti-reflection film resin is 0-15 wt%.

Further, the bottom antireflective film resin further comprises an alcohol-based structural unit derived from a polyol monomer represented by formula (3) or a polyepoxy monomer represented by formula (4);

in the formulae (3) and (4), X represents C₁～C₆A substituted or unsubstituted straight or branched hydrocarbon group, C₆～C₁₀A substituted or unsubstituted alicyclic hydrocarbon group of (C)₆～C₁₀The substituted or unsubstituted aromatic group or heterocyclic divalent group containing 1 to 3 nitrogen atoms, wherein the linear alkyl group, branched alkyl group, alicyclic alkyl group, aromatic group and heterocyclic divalent groupOptionally including at least one substituent.

Further, the bottom antireflective film resin is produced by polymerizing a diester-based compound with a polyol monomer having a structure represented by formula (3) or a polyepoxy monomer having a structure represented by formula (4), the diester-based compound including a fluorine-containing diester-based monomer having a structural unit represented by formula (5) and optionally a fluorine-free diester-based monomer having a structural unit represented by formula (6);

in the formulae (3) and (4), X represents C₁～C₆A substituted or unsubstituted straight or branched hydrocarbon group, C₆～C₁₀A substituted or unsubstituted alicyclic hydrocarbon group of (C)₆～C₁₀The substituted or unsubstituted aromatic group or the heterocyclic divalent group comprises 1-3 nitrogen atoms, and at least one substituent is optionally included on the straight-chain alkyl group, the branched-chain alkyl group, the alicyclic alkyl group, the aromatic group and the heterocyclic divalent group; in the formula (5), Ar represents a benzene ring or a naphthalene ring, and n and m independently represent an integer of 1-6; in the formula (6), Ar' represents a benzene ring or a naphthalene ring, and m represents an integer of 1-6.

Further, the polyol monomer is selected from at least one of the following formulas:

further, the multi-epoxy monomer is selected from at least one of the following formulas:

the invention also provides a bottom anti-reflection film composition, wherein the bottom anti-reflection film composition contains the bottom anti-reflection film resin and a solvent.

Further, the content of the bottom anti-reflection film resin is 0.5 to 15 wt% based on the total weight of the bottom anti-reflection film composition.

Further, the bottom antireflective film composition further contains at least one of a crosslinking agent, a catalyst and a surfactant.

In addition, the present invention also provides a pattern forming method, including the steps of: forming a material layer on a substrate; applying the bottom anti-reflective film composition onto a material layer and performing a heat treatment to form a bottom anti-reflective film; forming a photoresist resist layer on the bottom anti-reflection film; exposing and developing the photoresist resist layer to form a photoresist pattern; selectively removing a portion of the bottom anti-reflection film using the photoresist pattern to expose a portion of the material layer; the exposed portions of the material layer are etched.

After intensive research, the inventor of the present invention finds that the light absorption wavelength of the bottom anti-reflection film resin can be shifted by selecting the benzene-containing or naphthalene-containing bottom anti-reflection film resin with a symmetrical diester group and introducing the perfluoroalkyl group into the benzene ring or naphthalene ring of the bottom anti-reflection film resin, so that the bottom anti-reflection film resin can significantly reduce the absorbance while having a higher refractive index. The bottom anti-reflection film resin can properly control the absorption of exposure wavelength by controlling the content of the fluorine-containing diester-based structural unit and the fluorine-free diester-based structural unit, can widely set the focus position (wide focus depth allowance) for obtaining a proper photoresist shape, and has great industrial application prospect.

Detailed Description

The present invention is described in detail below.

Bottom antireflective film resin

The bottom anti-reflection film resin provided by the invention comprises a fluorine-containing diester-based structural unit shown in a formula (1) and an optional fluorine-free diester-based structural unit shown in a formula (2), namely, the resin necessarily comprises the fluorine-containing diester-based structural unit shown in the formula (1), and the fluorine-free diester-based structural unit shown in the formula (2) can be optionally contained, so that the content of the fluorine-free diester-based structural unit shown in the formula (2) can be increased when the absorbance needs to be properly increased, and the fluorine-free diester-based structural unit shown in the formula (2) can be not used or can be rarely used when the absorbance needs to be reduced. Specifically, the ratio of the fluorine-containing diester-based structural unit in the molecular chain of the bottom anti-reflection film resin is 30 wt% or more, preferably 35 to 60 wt%, and specifically may be 30 wt%, 32 wt%, 35 wt%, 38 wt%, 40 wt%, 42 wt%, 45 wt%, 48 wt%, 50 wt%, 52 wt%, 55 wt%, 58 wt%, 60 wt%, and the like. The proportion of the fluorine-free diester-based structural unit in the molecular chain of the bottom anti-reflection film resin is 0-20 wt%, preferably 0-15 wt%, and specifically may be 0 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, and the like.

The bottom antireflective film resin provided by the present invention further comprises an alcohol-based structural unit derived from a polyol monomer represented by formula (3) or a polyepoxy monomer represented by formula (4);

HO-X-OH formula (3),

in the formulae (3) and (4), X represents C₁～C₆A substituted or unsubstituted straight or branched hydrocarbon group, C₆～C₁₀A substituted or unsubstituted alicyclic hydrocarbon group of (C)₆～C₁₀The substituted or unsubstituted aromatic group or the heterocyclic divalent group comprises 1-3 nitrogen atoms, and at least one substituent is optionally included on the straight-chain alkyl group, the branched-chain alkyl group, the alicyclic alkyl group, the aromatic group and the heterocyclic divalent group. Specific examples of the linear or branched hydrocarbon group include, but are not limited to: methylene, ethylene, n-propylene, isopropylene, n-butylene, sec-butylene, isobutylene, tert-butylene, n-pentylene, isopentylene, tert-pentylene, or neopentylene. Specific examples of the alicyclic hydrocarbon group include, but are not limited to: cyclopentylene or cyclopentylene ringAnd hexyl. Specific examples of the aromatic group include, but are not limited to: phenylene, phenylmethyl, tolylene. Specific examples of the heterocyclic divalent group including 1 to 3 nitrogen atoms include, but are not limited to: isocyanuric acid groups.

In a preferred embodiment of the present invention, the polyol monomer is selected from at least one of the following formulae:

in a preferred embodiment of the present invention, the polyepoxy monomer is selected from at least one of the following formulas:

the weight average molecular weight Mw of the bottom anti-reflection film resin is 1000 to 100000, and may be, for example, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000, 20000, 30000, 40000, 50000, 60000, 70000, 80000, 90000, 100000, or the like. When the weight average molecular weight Mw of the bottom anti-reflective film resin exceeds 100000, the coatability of the bottom anti-reflective film composition containing the bottom anti-reflective film resin may be deteriorated; when the weight average molecular weight Mw of the bottom anti-reflective film resin is less than 1000, the bottom anti-reflective film composition containing the bottom anti-reflective film resin generates more volatile substances during heating, and pollutes equipment tables. In addition, the molecular weight distribution PDI of the bottom anti-reflection film resin is preferably 1.5-2.0.

In a preferred embodiment of the present invention, the bottom antireflective film resin is produced by polymerizing a diester-based compound with a polyol monomer having a structure represented by formula (3) or a polyepoxy monomer having a structure represented by formula (4), the diester-based compound including a fluorine-containing diester-based monomer having a structural unit represented by formula (5) and optionally a fluorine-free diester-based monomer having a structural unit represented by formula (6);

HO-X-OH formula (3),

in the formulae (3) and (4), X represents C₁～C₆A substituted or unsubstituted straight or branched hydrocarbon group, C₆～C₁₀A substituted or unsubstituted alicyclic hydrocarbon group of (C)₆～C₁₀The substituted or unsubstituted aromatic group or the heterocyclic divalent group comprises 1-3 nitrogen atoms, and at least one substituent is optionally included on the straight-chain alkyl group, the branched-chain alkyl group, the alicyclic alkyl group, the aromatic group and the heterocyclic divalent group; in the formula (5), Ar represents a benzene ring or a naphthalene ring, and n and m independently represent an integer of 1-6; in the formula (6), Ar' represents a benzene ring or a naphthalene ring, and m represents an integer of 1-6.

In one embodiment of the present invention, the bottom anti-reflective film resin is obtained by the following method: the diester-based compound is added to an organic solvent together with a polyol monomer or a polyepoxy monomer and a certain amount of a catalyst, followed by heating to effect polymerization. The organic solvent must have a relatively high boiling point and not chemically react with the aforementioned compounds and catalysts. Specific examples of the catalyst include, but are not limited to: p-toluenesulfonic acid, sulfuric acid, phosphoric acid, and the like. The polymerization reaction conditions include that the temperature can be 50-180 ℃, and preferably 90-150 ℃; the time can be 1-50 h, preferably 6-12 h. Further, the polymerization reaction may employ solution polymerization, suspension polymerization, emulsion polymerization, or the like.

The ratio of the bottom anti-reflective film resin in the bottom anti-reflective film composition is preferably 0.5 to 15 wt%, more preferably 0.5 to 10 wt%, and specifically may be 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 7 wt%, 7.5 wt%, 8 wt%, 8.5 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, or the like.

Solvent(s)

The solvent in the bottom antireflective film composition can be any of a variety of inert liquid materials that are sufficient to dissolve or disperse the bottom antireflective film resin, specific examples of which include, but are not limited to: ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, toluene, xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, methyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutyrate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, ethyl pyruvate, ethyl acetate, butyl acetate, methyl acetate, ethyl acetate, methyl acetate, ethyl acetate, methyl acetate, ethyl acetate, methyl acetate, ethyl acetate, methyl acetate, ethyl acetate, methyl acetate, ethyl acetate, methyl acetate, at least one of ethyl lactate and butyl lactate. Among these solvents, at least one selected from the group consisting of propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, ethyl lactate, butyl lactate and cyclohexanone is preferable. Further, a high boiling point solvent such as propylene glycol monobutyl ether, propylene glycol monobutyl ether acetate, or the like may be used in combination.

Crosslinking agent

The bottom antireflective film composition may further contain a crosslinking agent. Specific examples of the crosslinking agent include, but are not limited to: at least one of an amino resin, a glycoluril compound, an epoxy compound, melamine, and a melamine derivative.

The content of the crosslinking agent is preferably 0 to 20 wt% based on the total weight of the bottom anti-reflection film composition.

Catalyst and process for preparing same

The bottom antireflective film composition may further contain a catalyst. Wherein, the catalyst is generally an acidic compound, which plays a role in promoting the crosslinking reaction, and specific examples thereof include, but are not limited to, at least one of the structures shown in formula (12) to formula (17).

The catalyst is preferably contained in an amount of 0.1 to 5 wt% based on the total weight of the bottom anti-reflection film composition. When the amount of the catalyst is too small, the curing rate is slow; when the amount of the catalyst used is too large, the catalyst is decomposed in a large amount to generate smoke due to poor heat resistance, and thus the equipment is contaminated.

Surface active agent

The bottom antireflective film composition may further comprise a surfactant. 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 alkylaryl ethers such as polyoxyethylene octylphenol ether and polyoxyethylene nonylphenol ether, and sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monoleate, sorbitan monolaurate and sorbitan tristearate, at least one polyoxyethylene sorbitan fatty acid ester such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monolaurate, and polyoxyethylene sorbitan tristearate.

The surfactant is preferably contained in an amount of 0.01 to 0.8 wt% based on the total weight of the bottom anti-reflective film composition.

Pattern forming method

The pattern forming method provided by the invention comprises the following steps: forming a material layer on a substrate; applying the bottom anti-reflection film composition on the material layer and performing heat treatment to form a bottom anti-reflection film; forming a photoresist resist layer on the bottom anti-reflection film; exposing and developing the photoresist resist layer to form a photoresist pattern; selectively removing a portion of the bottom anti-reflection film using the photoresist pattern to expose a portion of the material layer; the exposed portions of the material layer are etched.

The substrate may be a silicon wafer, a glass substrate, or a polymer substrate.

The material layer is a material to be finally patterned, and may be, for example, a silicon antireflection layer, 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 bottom antireflective film composition is coated on the material layer in the form of a solution and preferably by spin coating. Here, the thickness of the bottom anti-reflection film composition is not particularly limited, and may be, for example, 100 to 10000 angstrom. In addition, the heat treatment conditions include a temperature of 120 to 250 ℃ and a time of 10 seconds to 10 minutes.

The photoresist resist layer may be formed of, for example, ArF type, KrF type, or EUV type photoresist.

The method of exposing the photoresist resist layer may be ArF, KrF, or EUV, for example.

The present invention will be described in more detail with reference to examples and comparative examples. However, these examples are merely illustrative, and the present invention is not limited thereto.

Synthesis of bottom antireflective film resin

Synthesis example 1

At normal temperature, 270g of dimethyl 4-trifluoromethylphthalate, 291g of tris (2-hydroxyethyl) isocyanurate, 9.4g of p-toluenesulfonic acid and 400mL of anisole are added into a 2000mL three-necked flask provided with a stirrer, a reflux condenser and a water separator; under the protection of nitrogen, heating to 150 ℃, and starting reaction timing when the reaction system begins to reflux after the reactants are dissolved; reacting for about 8 hours, cooling to room temperature, and adding tetrahydrofuran to dilute the reaction solution; slowly adding the diluted reaction solution into a large amount of isopropanol/n-heptane mixed solvent, precipitating, filtering, and drying a filter cake at 60 ℃ for 24h to obtain the bottom anti-reflection film resin, wherein the bottom anti-reflection film resin comprises the fluorine-containing diester-based structural unit shown in the formula (1) and the alcohol-based structural unit derived from the polyalcohol monomer shown in the formula (3). In the formula (1), Ar is a benzene ring. In formula (3), X is a heterocyclic divalent group including three nitrogen atoms. The bottom antireflective film resin had a number average molecular weight Mw of 2600 and a molecular weight distribution PDI of 1.52.

Synthesis example 2

189g of dimethyl 4-trifluoromethylphthalate, 60g of dimethyl terephthalate, 291g of tris (2-hydroxyethyl) isocyanurate, 9.4g of p-toluenesulphonic acid and 400mL of anisole were added to a 2000mL three-necked flask equipped with a stirrer, a reflux condenser and a water separator at room temperature; under the protection of nitrogen, heating to 150 ℃, and starting reaction timing when the reaction system begins to reflux after the reactants are dissolved; reacting for about 8 hours, cooling to room temperature, and adding tetrahydrofuran to dilute the reaction solution; slowly adding the diluted reaction solution into a large amount of isopropanol/n-heptane mixed solvent, precipitating, filtering, and drying a filter cake at 60 ℃ for 24h to obtain the bottom anti-reflection film resin, wherein the bottom anti-reflection film resin comprises a fluorine-containing diester-based structural unit shown in a formula (1), a fluorine-free diester-based structural unit shown in a formula (2) and an alcohol-based structural unit derived from a polyol monomer shown in a formula (3). In the formula (1), Ar is a benzene ring. In the formula (2), Ar' is a benzene ring. In formula (3), X is a heterocyclic divalent group including three nitrogen atoms. The number average molecular weight Mw of the bottom anti-reflective film resin was 3280, and the molecular weight distribution PDI was 1.77.

Synthesis example 3

At normal temperature, 135g of dimethyl 4-trifluoromethylphthalate, 26g of glycerol, 74g of tris (2-hydroxyethyl) isocyanurate, 5.7g of p-toluenesulfonic acid and 170mL of anisole are added into a 1000mL three-necked flask provided with a stirrer, a reflux condenser and a water separator; under the protection of nitrogen, heating to 150 ℃, and starting reaction timing when the reaction system begins to reflux after the reactants are dissolved; reacting for about 5 hours, cooling to room temperature, and adding tetrahydrofuran to dilute the reaction solution; slowly adding the diluted reaction solution into a large amount of isopropanol/n-heptane mixed solvent, precipitating, filtering, and drying a filter cake at 60 ℃ for 24h to obtain the bottom anti-reflection film resin, wherein the bottom anti-reflection film resin comprises the fluorine-containing diester-based structural unit shown in the formula (1) and the alcohol-based structural unit derived from the polyalcohol monomer shown in the formula (3). In the formula (1), Ar is a benzene ring. In formula (3), X is a hydroxyalkylene group or a heterocyclic divalent group including three nitrogen atoms. The bottom antireflective film resin had a number average molecular weight Mw of 3510 and a molecular weight distribution PDI of 1.81.

Synthesis example 4

189g of dimethyl 4-trifluoromethylphthalate, 35g of dimethyl 2, 6-naphthalenedicarboxylate, 291g of tris (2-hydroxyethyl) isocyanurate, 9.4g of p-toluenesulphonic acid and 400mL of anisole were placed in a 2000mL three-necked flask equipped with a stirrer, a reflux condenser and a water separator at room temperature; under the protection of nitrogen, heating to 150 ℃, and starting reaction timing when the reaction system begins to reflux after the reactants are dissolved; reacting for about 8 hours, cooling to room temperature, and adding tetrahydrofuran to dilute the reaction solution; slowly adding the diluted reaction solution into a large amount of isopropanol/n-heptane mixed solvent, precipitating, filtering, and drying a filter cake at 60 ℃ for 24h to obtain the bottom anti-reflection film resin, wherein the bottom anti-reflection film resin comprises a fluorine-containing diester-based structural unit shown in a formula (1), a fluorine-free diester-based structural unit shown in a formula (2) and an alcohol-based structural unit derived from a polyol monomer shown in a formula (3). In the formula (1), Ar is a benzene ring. In the formula (2), Ar' is a naphthalene ring. In formula (3), X is a heterocyclic divalent group including three nitrogen atoms. The bottom antireflective film resin had a number average molecular weight Mw of 3280 and a molecular weight distribution PDI of 1.77.

Comparative Synthesis example 1

At normal temperature, 40g of dimethyl terephthalate, 60g of tris (2-hydroxyethyl) isocyanurate, 2.4g of p-toluenesulfonic acid and 70mL of anisole are added into a 500mL three-neck flask provided with a stirrer, a reflux condenser and a water separator; under the protection of nitrogen, heating to 150 ℃, and starting reaction timing when the reaction system begins to reflux after the reactants are dissolved; reacting for about 5 hours, cooling to room temperature, and adding tetrahydrofuran to dilute the reaction solution; and slowly adding the diluted reaction solution into a large amount of isopropanol/n-heptane mixed solvent, separating out a precipitate, filtering, and drying a filter cake at 60 ℃ for 24 hours to obtain the reference bottom anti-reflection film resin. The reference bottom antireflective film resin had a number average molecular weight Mw of 3500 and a molecular weight distribution PDI of 1.31.

Comparative Synthesis example 2

At normal temperature, a 1000mL three-neck flask provided with a stirrer, a reflux condenser tube and a water separator is added with 45g of dimethyl terephthalate, 36g of dimethyl 5-hydroxyisophthalate, 106g of tris (2-hydroxyethyl) isocyanurate, 4g of p-toluenesulfonic acid and 170mL of anisole; under the protection of nitrogen, heating to 150 ℃, and starting reaction timing when the reaction system begins to reflux after the reactants are dissolved; reacting for about 5 hours, cooling to room temperature, and adding tetrahydrofuran to dilute the reaction solution; and slowly adding the diluted reaction solution into a large amount of isopropanol/n-heptane mixed solvent, separating out a precipitate, filtering, and drying a filter cake at 60 ℃ for 24 hours to obtain the reference bottom anti-reflection film resin. The reference bottom antireflective film resin had a number average molecular weight Mw of 3300 and a molecular weight distribution PDI of 1.29.

Comparative Synthesis example 3

At normal temperature, 29g of dimethyl nitroterephthalate, 14g of glycerol, 0.3g of p-toluenesulfonic acid and 40mL of anisole are added into a 250mL three-neck flask provided with a stirrer, a reflux condenser and a water separator; under the protection of nitrogen, heating to 150 ℃, and starting reaction timing when the reaction system begins to reflux after the reactants are dissolved; reacting for about 25h, cooling to room temperature, and adding tetrahydrofuran to dilute the reaction solution; and slowly adding the diluted reaction solution into a large amount of isopropanol/n-heptane mixed solvent, separating out a precipitate, filtering, and drying a filter cake at 60 ℃ for 24 hours to obtain the reference bottom anti-reflection film resin. The reference bottom antireflective film resin had a number average molecular weight Mw of 2100 and a molecular weight distribution PDI of 1.36.

Examples and comparative examples

Adding the bottom anti-reflection film resin, the solvent, the cross-linking agent and the catalyst into a clean bottle according to the proportion shown in the table 1, oscillating until all components are completely dissolved, and then respectively filling each sample into a new clean bottle through a 0.2-micrometer PTFE film filter to obtain the bottom anti-reflection film composition. Wherein the solvent is Propylene Glycol Monomethyl Ether Acetate (PGMEA), the catalyst is p-toluenesulfonic acid, and the cross-linking agent is a glycoluril compound with the structure shown as follows:

TABLE 1 (wt%)

Test example

The bottom anti-reflective film was prepared by spin coating the above examples and comparative samples on 8 inch wafers using ACT 12. The spin speed is changed as required to obtain a film thickness of 40-120 nm. Wherein the curing temperature is 215 ℃ and the curing time is 60 s. The film thickness was measured by a film thickness meter (from KLA) and the refractive index (n) and absorbance (k) were measured by an ellipsometer (from Woollman), the results of which are shown in table 2. In Table 2, the thickness of the bottom anti-reflection film is 50 nm.

TABLE 2

Item	Refractive index (n)	Absorbance (k)
			Example 1	1.82	0.29
Example 2	1.82	0.35
			Example 3	1.70	0.21
Example 4	1.72	0.30
			Comparative example 1	1.83	0.52
Comparative example 2	1.82	0.40
			Comparative example 3	1.71	0.32

As can be seen from comparison of example 1 and comparative example 1, introduction of a trifluoromethyl group can significantly reduce the absorbance of the bottom anti-reflective film. As can be seen from comparison of example 1 and comparative example 2, the trifluoromethyl group can significantly reduce the absorbance of the bottom anti-reflective film more than the hydroxyl group. As can be seen from comparison of example 3 and comparative example 3, the trifluoromethyl group can more significantly reduce the absorbance of the bottom anti-reflective film than the nitro group. In addition, the bottom anti-reflection film resin and the composition provided by the invention basically cannot reduce the refractive index, namely, have high refractive index and low absorbance, and have great industrial application prospects.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made in the above embodiments by those of ordinary skill in the art without departing from the principle and spirit of the present invention.