Bottom anti-reflection coating for 193nm photoetching as well as preparation method and application of bottom anti-reflection coating

Abstract

The invention discloses a bottom anti-reflection coating for 193nm photoetching as well as a preparation method and application of the bottom anti-reflection coating. The preparation method of the bottom anti-reflection coating comprises the following steps: casting a bottom anti-reflection coating composition on a semiconductor substrate, and roasting to obtain the bottom anti-reflection coating, wherein the composition of the bottom anti-reflection coating comprises a ternary polymer, a solvent and a photoacid generator. According to the bottom anti-reflection coating, an etching process can be avoided, damage of plasmas to a base body is reduced, operation procedures are reduced, and then production efficiency is improved;

Description

TECHNICAL FIELD

[0001] The present application relates to a bottom anti-reflective coating for 193nm photolithography and a preparation method and application thereof. BACKGROUND

[0002] Photoresist is a key material in the photolithography process. In photolithography projection, the pattern on the mask is projected on the photosensitive substance, and through photochemical reaction, after baking and developing, the photosensitive substance achieves the purpose of transferring pattern. These patterns act as a barrier layer to realize the subsequent etching and ion implantation process.

[0003] Photoresist can transfer fine patterns on the mask to the substrate through processes such as coating, baking, exposure, development, and etching. The shorter the exposure wavelength, the higher the resolution of the photoresist. With the development of exposure wavelength from G line (436nm), I line (365nm), KrF (248nm), ArF (193nm), EUV (13.5nm), the structure of photoresist has also changed. In recent years, Moore's law continues to advance, and semiconductor processes have gradually improved. ArF immersion lithography has become the dominant lithography process for advanced processes, combined with multiple exposure processes, with a resolution of 45-7nm. ArF immersion lithography continues the ArF light source, increases the water medium (the refractive index of water is 1.44) between the photoresist and the lithography machine lens, increases the numerical aperture (NA) of the lithography machine, and improves the resolution and depth of focus of the photoresist.

[0004] However, when the wavelength of the exposure light source becomes shorter, the light interference effect caused by the reflected light reflected on the etching layer of the semiconductor substrate increases, and due to undercutting, notching, etc., the problem of poor pattern profile or reduced size uniformity occurs. In order to prevent the above problems, a bottom anti-reflective coating (BARC) for absorbing exposure light (reflected light) is usually formed between the etching layer and the photoresist film.

[0005] Currently, there are two kinds of etching processes commonly used for anti-reflective coatings: etching type and alkali dissolution type. Both processes are to coat an anti-reflective coating on a substrate, then spin a layer of photoresist on it, and then perform processes such as pre-baking, exposure, post-baking, and development. For photoresist development patterning, there is no difference between the two processes, and the biggest difference between the two is the removal process of the coating. The etching type anti-reflective coating is mainly removed by plasma, while the alkali dissolution type anti-reflective coating is removed by a mechanism similar to photoresist development and reaction with the developer. Both processes have their advantages and disadvantages. The etching process has been widely used in industrial production and has certain controllability and maturity. Although the alkali dissolution type anti-reflective coating can avoid etching process, reduce the damage of plasma to the substrate, reduce the operation process, and improve the production efficiency, it needs to consider the baking conditions, dissolution rate, post-development residue (PDR), and other problems. Therefore, there is an urgent need to develop excellent alkali-dissolvable bottom anti-reflective coating (BARC) materials in the industry. SUMMARY

[0006] The technical problem to be solved by the present application is to overcome the problems of baking conditions, dissolution rate, and post-development residue of the existing alkali-dissolvable anti-reflective coating. The present application provides a bottom anti-reflective coating for 193nm lithography, which can avoid etching process, reduce the damage of plasma to the substrate, and reduce the operation process, thereby improving the production efficiency.

[0007] The present application provides a preparation method of a ternary polymer, which comprises the following steps:

[0008] In the presence of a crosslinking agent as shown in formula (L) and an initiator, a monomer as shown in formula (A), a monomer B, and a monomer as shown in formula (C) are polymerized in a solvent to obtain a ternary polymer; the monomer B is hydroxyethyl methacrylate and / or hydroxypropyl methacrylate;

[0009] The amount of the monomer as shown in formula (A) is 500-800 parts by weight, the amount of the monomer B is 500-800 parts by weight, and the amount of the monomer as shown in formula (C) is 500-800 parts by weight;

[0010] A: C: L:

[0011] In the present application, the weight average molecular weight of the terpolymer is preferably 2000 to 5000000, more preferably 3000 to 100000, for example 6851, 6351, 6952, 5988, 6432 or 6137, when measured by gel permeation chromatography (GPC) using standard polystyrene.

[0012] In the present application, the amount of the crosslinking agent represented by formula (L) is preferably 100 to 300 parts by weight, more preferably 100, 200 or 300 parts by weight.

[0013] In the present application, the initiator is one of 2,2'-azobis(isobutyronitrile), 2,2'-azobis-dimethyl-(2-methylpropionitrile), 2,2'-azobis-(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2-cyclopropylpropionitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 1,1'-azobis(cyclohexanecarbonitrile), benzoyl peroxide, t-butyl peroxybenzoate, di-t-butylperoxyphthalate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxy pivalate, t-amyl peroxy pivalate and butyllithium, preferably 2,2'-azobis(isobutyronitrile).

[0014] In the present application, the amount of the initiator is 1 to 10 wt%, the percentage being the ratio of the weight of the initiator to the total weight of all monomers, preferably 4 to 6 wt%, more preferably 4 wt%, 4.8 wt%, 5 wt% and 6 wt%.

[0015] In the present application, the amount of the monomer represented by formula (A) is preferably 500, 650 or 800 parts by weight.

[0016] In the present application, the amount of the monomer B is preferably 500, 650 or 800 parts by weight.

[0017] In the present application, the amount of the monomer represented by formula (C) is preferably 500, 650 or 800 parts by weight.

[0018] In the present application, the solvent can be an organic solvent, preferably one or more of an aromatic hydrocarbon solvent, an ether solvent, a ketone solvent, an amide solvent, a sulfoxide solvent, and an ester solvent. The aromatic hydrocarbon solvent is preferably toluene and / or benzene. The ether solvent is preferably tetrahydrofuran. The ketone solvent is preferably methyl amyl ketone. The amide solvent is preferably N,N'-dimethylformamide. The sulfoxide solvent is preferably dimethyl sulfoxide. The ester solvent is preferably ethyl lactate and / or propylene glycol monomethyl ether acetate. The organic solvent is more preferably an amide solvent and a ketone solvent, such as N,N'-dimethylformamide and methyl amyl ketone.

[0019] In the present application, the preparation method preferably comprises the following steps:

[0020] (1) preheating the solvent;

[0021] (2) mixing the monomer represented by formula (A), the monomer B, the monomer represented by formula (C), the crosslinking agent represented by formula (L), an initiator, and the solvent to obtain a mixed solution;

[0022] (3) adding the mixed solution to the preheated solvent to perform a polymerization reaction;

[0023] The step (1) and the step (2) are not in a specific order.

[0024] In an embodiment, in the preparation method of the terpolymer, the preheating temperature in the step (1) is preferably 80-100°C, more preferably 90°C.

[0025] In an embodiment, in the preparation method of the terpolymer, the solvent in the step (1) can be an organic solvent, preferably one or more of an aromatic hydrocarbon solvent, an ether solvent, a ketone solvent, an amide solvent, a sulfoxide solvent, and an ester solvent. The aromatic hydrocarbon solvent is preferably toluene and / or benzene. The ether solvent is preferably tetrahydrofuran. The ketone solvent is preferably methyl amyl ketone. The amide solvent is preferably N,N'-dimethylformamide. The sulfoxide solvent is preferably dimethyl sulfoxide. The ester solvent is preferably ethyl lactate and / or propylene glycol monomethyl ether acetate. The organic solvent is more preferably an amide solvent and a ketone solvent, such as N,N'-dimethylformamide and methyl amyl ketone.

[0026] In an embodiment, in the preparation method of the terpolymer, the amount of the solvent in the step (1) is preferably 600-1000 parts by weight, more preferably 1000 parts by weight. If two or more kinds of solvents are contained at the same time, the amounts of different solvents are preferably the same.

[0027] In one embodiment, in the preparation method of the terpolymer, the solvent I is purged with nitrogen in step (1), and the purging time is preferably 20 to 50 minutes, more preferably 30 minutes.

[0028] In one embodiment, in the preparation method of the terpolymer, the solvent in step (2) is an organic solvent, preferably one or more of aromatic hydrocarbon solvents, ether solvents, ketone solvents, amide solvents, sulfoxide solvents and ester solvents. The aromatic hydrocarbon solvent is preferably toluene and / or benzene. The ether solvent is preferably tetrahydrofuran. The ketone solvent is preferably methyl amyl ketone. The amide solvent is preferably N,N'-dimethylformamide. The sulfoxide solvent is preferably dimethyl sulfoxide. The ester solvent is preferably ethyl lactate and / or propylene glycol monomethyl ether acetate. The organic solvent is more preferably an amide solvent and a ketone solvent, such as N,N'-dimethylformamide and methyl amyl ketone.

[0029] In one embodiment, in the preparation method of the terpolymer, the amount of the solvent in step (2) is preferably 6000 to 10000 parts by weight, more preferably 7000 parts by weight. If two or more solvents are used at the same time, the amounts of different solvents are preferably the same.

[0030] In one embodiment, in the preparation method of the terpolymer, the amount of the initiator in step (2) is 1 to 10 wt%, and the percentage is the ratio of the weight of the initiator to the total weight of all monomers, preferably 4 to 6 wt%, and more preferably 4 wt%, 4.8 wt%, 5 wt% and 6 wt%.

[0031] In one embodiment, in the preparation method of the terpolymer, the mixed solution is purged with nitrogen in step (2). The purging time is preferably 30 minutes.

[0032] In one embodiment, in the preparation method of the terpolymer, the mixed solution is added to the preheated solvent in step (3) by peristaltic pump introduction. The introduction time is preferably 2.5 hours.

[0033] In one embodiment, in the preparation method of the terpolymer, the polymerization reaction time in step (3) is 5 to 7 hours, more preferably 6 hours.

[0034] In the preparation method of the terpolymer, the polymerization reaction can be separated and purified by conventional post-treatment in the art, or the reaction solution can be directly used as a raw material without separation and purification of the polymer.

[0035] The preparation method of the terpolymer, the post-treatment of the polymerization reaction can use the conventional post-treatment in the art, which preferably comprises the following steps: cooling, adding an organic solvent to the reaction solution, removing the supernatant, dissolving the remaining reaction mixture in tetrahydrofuran, pouring the obtained solution into water, filtering and drying.

[0036] In an embodiment, the preparation method of the terpolymer, the cooling in the post-treatment of the polymerization reaction is preferably cooling the reaction solution to room temperature.

[0037] In an embodiment, the preparation method of the terpolymer, the organic solvent in the post-treatment of the polymerization reaction is preferably a poor solvent of the polymer but a good solvent of the polymer solvent, more preferably n-hexane or n-heptane, and most preferably n-heptane. The amount of the organic solvent is preferably 6000 parts by weight.

[0038] In an embodiment, the preparation method of the terpolymer, the amount of water in the post-treatment of the polymerization reaction is preferably 100000 parts by weight.

[0039] In an embodiment, the preparation method of the terpolymer, the filtering in the post-treatment of the polymerization reaction is preferably reduced pressure filtration.

[0040] In an embodiment, the preparation method of the terpolymer, the drying in the post-treatment of the polymerization reaction is preferably drying overnight in a vacuum oven. The temperature of the vacuum oven is preferably set to 45°C.

[0041] The present application provides a terpolymer prepared by the preparation method as described above.

[0042] The present application provides a composition of a bottom anti-reflective coating, which comprises the terpolymer as described above, a solvent and a photo-acid generator.

[0043] The present application provides a composition of a bottom anti-reflective coating, which comprises the terpolymer as described above, a solvent and a photo-acid generator.

[0044] The solvent in the composition of the bottom antireflection coating is a conventional solvent in the field of antireflection coating, and is preferably one or more of an ether solvent, an ester solvent, an alcohol solvent, an aromatic hydrocarbon solvent, a ketone solvent, and an amide solvent. The ether solvent is preferably one or more of propylene glycol monobutyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and propylene glycol monomethyl ether. The ester solvent is preferably one or more of propylene glycol monobutyl ether acetate, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether acetate, propylene glycol propyl ether acetate, 2-hydroxypropionic acid ethyl ester, 2-hydroxy-2-methyl-propionic acid ethyl ester, ethoxyacetic acid ethyl ester, hydroxyacetic acid ethyl ester, 2-hydroxy-3-methylbutyric acid methyl ester, 3-methoxypropionic acid methyl ester, 3-methoxypropionic acid ethyl ester, 3-ethoxypropionic acid ethyl ester, 3-ethoxypropionic acid methyl ester, pyruvic acid methyl ester, pyruvic acid ethyl ester, acetic acid ethyl ester, acetic acid butyl ester, lactic acid ethyl ester, and lactic acid butyl ester. The alcohol solvent is preferably propylene glycol. The aromatic hydrocarbon solvent is preferably toluene and / or xylene. The ketone solvent is preferably one or more of methyl ethyl ketone, cyclopentanone, and cyclohexanone. The amide solvent is preferably one or more of N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone. The solvent is more preferably propylene glycol monobutyl ether and / or propylene glycol monobutyl ether acetate.

[0045] The solvent in the composition of the bottom antireflection coating is used in an amount capable of dissolving all the components, and is preferably 1000 to 2500 parts by weight, more preferably 1200 to 2000 parts by weight, for example, 1200, 1500, or 2000, further preferably 1500 to 1800 parts by weight.

[0046] The photoacid generator in the composition of the bottom antireflection coating can be any compound capable of generating an acid upon exposure to a KrF excimer laser (wavelength: 248 nm), an ArF excimer laser (wavelength: 193 nm), or the like, and is preferably one or more of an onium salt compound, a sulfone imide derivative, and a disulfonyl diazomethane compound.

[0047] The onium salt compound is preferably an iodonium salt compound, a sulfonium salt compound, or a cross-linkable onium salt compound. The iodonium salt compound is preferably one or more of diphenyl iodonium hexafluorophosphate, diphenyl iodonium triflate, diphenyl iodonium nonafluoro-n-butane sulfonate, diphenyl iodonium perfluoro-n-octane sulfonate, diphenyl iodonium camphor sulfonate, bis(4-tert-butylphenyl) iodonium camphor sulfonate, and bis(4-tert-butylphenyl) iodonium triflate. The sulfonium salt compound is preferably one or more of triphenyl sulfonium hexafluoroantimonate, triphenyl sulfonium nonafluoro-n-butane sulfonate, triphenyl sulfonium camphor sulfonate, and triphenyl sulfonium triflate, more preferably triphenyl sulfonium hexafluoroantimonate and / or triphenyl sulfonium triflate. The cross-linkable onium salt compound is preferably one or more of bis(4-hydroxyphenyl)(phenyl) sulfonium triflate, bis(4-hydroxyphenyl)(phenyl) sulfonium 1,1,2,2,3,3,4,4,4-nonafluoro-butane-1-sulfonate, phenyl bis(4-(2-(vinyloxy)ethoxy)-phenyl) sulfonium 1,1,2,2,3,3,4,4-octafluoro-butane-1,4-disulfonate, and tri(4-(2-(vinyloxy)ethoxy)-phenyl) sulfonium 1,1,2,2,3,3,4,4-octafluoro-butane-1,4-disulfonate.

[0048] The sulfone imide derivative is preferably one or more of N-(trifluoromethanesulfonyloxy)succinimide, N-(fluoro-n-butanesulfonyloxy)succinimide, N-(camphor sulfonyloxy)succinimide, and N-(trifluoromethylsulfonyloxy)naphthalene dicarboxylic imide.

[0049] The disulfonyl diazomethane compound is preferably one or more of bis(trifluoromethylsulfonyl) diazomethane, bis(cyclohexylsulfonyl) diazomethane, bis(benzenesulfonyl) diazomethane, bis(p-toluenesulfonyl) diazomethane, bis(2,4-dimethylbenzenesulfonyl) diazomethane, and methylsulfonyl-p-toluenesulfonyl diazomethane.

[0050] The amount of the photoacid generator in the composition of the bottom antireflective coating is preferably 1 to 20 parts by weight, for example, 1, 10, or 20.

[0051] The amount of the above-mentioned terpolymer in the composition of the bottom antireflective coating is 95 to 110 parts by weight, for example, 100 parts by weight.

[0052] The composition of the bottom antireflective coating can further contain other additional components, including polymers other than the above-mentioned polymers, surfactants, and smoothing agents. The amount of the additional components is not particularly limited and can be appropriately determined depending on the target coating.

[0053] The present application provides a preparation method of a composition of a bottom anti-reflective coating, comprising the following steps: mixing each component of the composition as described above.

[0054] In the preparation method of the composition, the mixing method is preferably stirring, and the stirring is preferably under the following conditions: stirring at room temperature for 30 minutes.

[0055] In the preparation method of the composition, after the mixing, a filtering step can be further included, and the filtering method can be filtering using a filter, and the pore size of the filter is preferably 0.2-0.05 μm, and more preferably 0.05 μm.

[0056] The present application provides an application of the composition of a bottom anti-reflective coating in preparing a bottom anti-reflective coating.

[0057] The present application provides a preparation method of a bottom anti-reflective coating, which is prepared by the following method, comprising the following steps: casting the composition as described above on a semiconductor substrate, and baking to obtain a bottom anti-reflective coating.

[0058] In the preparation method of the bottom anti-reflective coating, the tool for casting is preferably a spin coater or a coating machine, and preferably a spin coater.

[0059] In the preparation method of the bottom anti-reflective coating, the semiconductor substrate is preferably one of a silicon / silicon dioxide coated substrate, a silicon nitride substrate, a silicon wafer substrate, a glass substrate or an ITO substrate, and more preferably a silicon wafer substrate.

[0060] In the preparation method of the bottom anti-reflective coating, the baking temperature is preferably 80-250°C, more preferably 100-250°C, and most preferably 190°C.

[0061] In the preparation method of the bottom anti-reflective coating, the baking time is preferably 0.3-5 minutes, more preferably 0.5-2 minutes, and most preferably 1 minute.

[0062] The present application provides a bottom anti-reflective coating prepared by the above preparation method.

[0063] The present application provides an application of the above bottom anti-reflective coating in forming a photoresist pattern.

[0064] The present application also provides a method for forming a photoresist pattern on a bottom anti-reflective coating, comprising the following steps:

[0065] S1: coating a photoresist on the bottom anti-reflective coating as described above;

[0066] S2: soft baking;

[0067] S3: exposing;

[0068] S4: baking;

[0069] S5: developing.

[0070] In the method of forming a photoresist pattern on a bottom anti-reflective coating, the photoresist can be conventional in the art, preferably a positive type photoresist, a negative type photoresist or a negative tone development (NTD) photoresist, more preferably a positive type photoresist, such as a 248 nm positive type photoresist (SEPR-430™ (manufactured by Shin-Etsu)) or a 193 nm positive type photoresist (TOK company, tai-6990PH).

[0071] In the method of forming a photoresist pattern on a bottom anti-reflective coating, the temperature of the soft baking is preferably 100 to 140°C, more preferably 120°C. The time of the soft baking is preferably 0.5 to 2 minutes, more preferably 60 seconds.

[0072] In the method of forming a photoresist pattern on a bottom anti-reflective coating, the light of the exposing can be conventional in the art, preferably light of a wavelength of 13.5 to 248 nm, more preferably a KrF excimer laser (wavelength: 248 nm), an ArF excimer laser (wavelength: 193 nm) or an extreme UV light (wavelength: 13.5 nm).

[0073] In the method of forming a photoresist pattern on a bottom anti-reflective coating, the temperature of the baking is preferably 80 to 150°C, more preferably 100 to 140°C, most preferably 130°C.

[0074] In the method of forming a photoresist pattern on a bottom anti-reflective coating, the time of the baking is preferably 0.3 to 5 minutes, more preferably 0.5 to 2 minutes, most preferably 60 seconds.

[0075] In the method of forming a photoresist pattern on a bottom anti-reflective coating, the developing is performed using a developing solution. The developing solution can easily dissolve and remove the bottom anti-reflective coating.

[0076] The developing solution can be an alkali developing solution, preferably an aqueous solution of an alkali metal hydroxide, an aqueous solution of a tertiary ammonium hydroxide or an aqueous solution of an amine. The aqueous solution of an alkali metal hydroxide is preferably an aqueous solution of potassium hydroxide or an aqueous solution of sodium hydroxide. The aqueous solution of a tertiary ammonium hydroxide is preferably an aqueous solution of tetramethylammonium hydroxide (TMAH), an aqueous solution of tetraethylammonium hydroxide or an aqueous solution of choline. The aqueous solution of an amine is preferably an aqueous solution of ethanolamine, an aqueous solution of propylamine or an aqueous solution of ethylenediamine. The developing solution is more preferably an aqueous solution of 2.38 wt% of tetramethylammonium hydroxide.

[0077] In the method for forming a photoresist pattern on a bottom antireflection coating, the developing solution can further contain a surfactant.

[0078] In the method for forming a photoresist pattern on a bottom antireflection coating, the temperature of the developing solution is preferably 5-50°C, more preferably 25-40°C.

[0079] In the method for forming a photoresist pattern on a bottom antireflection coating, the developing time is preferably 10-300 seconds, more preferably 30-60 seconds.

[0080] On the basis of common general knowledge in the art, the above-mentioned preferred conditions can be combined arbitrarily, thus obtaining various preferred examples of the present application.

[0081] In the present application, the room temperature is 15-35°C, preferably 25°C.

[0082] The reagents and raw materials used in the present application are commercially available.

[0083] The positive progress effect of the present application is that the etching process can be avoided, the damage of plasma to the substrate is reduced and the operation process is reduced, thus improving the production efficiency. DETAILED DESCRIPTION

[0084] The present application will be further described by way of examples, but the present application is not limited to the examples. In the following examples, the experimental methods not specified in the examples are selected according to the conventional methods and conditions, or according to the instructions of the commercial products.

[0085] In the description of the examples, "parts" and "%" respectively mean "parts by weight" and "wt%", unless otherwise specified.

[0086] Example 1 A method for preparing a bottom antireflection coating

[0087] 1. Preparation of a terpolymer

[0088] The polymers P1 to P6, the comparative polymers CP1 to CP7 were prepared according to the following procedure. The amounts of the monomer of formula (A), the monomer B, the monomer of formula (C) and the crosslinking agent of formula (L) used for the preparation of each polymer are shown in Table 1.

[0089] A: B: hydroxyethyl methacrylate;

[0090] C: L:

[0091] A reaction vessel equipped with a stirrer, a condenser, a heater and a thermostat was charged with N,N'-dimethylformamide (500 parts) and methyl pentyl ketone (500 parts) by weight. The solvent was purged with nitrogen for 30 minutes and then heated to 90°C.

[0092] The monomer of formula (A), the monomer of formula (B), the monomer of formula (C), the crosslinking agent of formula (L), 2,2'-azobis(isobutyronitrile) (100 parts), N,N'-dimethylformamide (3500 parts) and methyl pentyl ketone (3500 parts) were placed in a sample vessel and stirred. The resulting mixture solution was purged with nitrogen for 30 minutes.

[0093] The mixture solution was then introduced into the reaction vessel by means of a peristaltic pump over a period of 2.5 hours. After the introduction was complete, the reaction mixture was kept at 80°C for 6 hours.

[0094] After cooling to room temperature, the mixture was poured into n-heptane (60000 parts). The supernatant was removed and the remaining reaction mixture was dissolved in tetrahydrofuran (6000 parts). The resulting solution was poured into water (100000 parts) to form a precipitate. The precipitate was isolated by filtration under reduced pressure and dried in a vacuum oven at 45°C overnight.

[0095] By drying, the polymer was obtained. The weight average molecular weight Mw of the product was measured by GPC (THF).

[0096] Table 1

[0097]

[0098] 2. Process for the preparation of a bottom antireflective coating

[0099] To the above prepared polymer, a solvent and a photoacid generator were added. The amounts of the solvent and the photoacid generator are shown in Table 2. The resulting mixture was stirred for 30 minutes at room temperature and then the mixture was filtered through a filter having a pore size of 0.05 μm to prepare a bottom antireflective coating forming composition in the form of a solution.

[0100] The prepared bottom anti-reflective coating forming composition was cast on a silicon wafer substrate by spin coating, and a bottom anti-reflective coating of the following compositions 1021-B12 and CB1-CB14 was prepared by cross-linking at 190°C for 60 seconds on a vacuum hot plate, wherein:

[0101] The polymers used in Table 2 are the polymers P1 to P6 and CP1-CP7 prepared in Table 1 above.

[0102] Table 2

[0103]

[0104]

[0105]

[0106] Application and effect of the bottom anti-reflective coating of Example 2

[0107] 1. Optical property measurement

[0108] The bottom anti-reflective coating obtained by ellipsometer measurement was measured for refractive index (n value) and extinction coefficient (k value) at 193 nm.

[0109] 2. Development property measurement

[0110] The method of forming a photoresist pattern and the development property of the bottom anti-reflective coating were measured when the exposure light wavelength was 193 nm.

[0111] A commercially available 193 nm positive photoresist (TOK Corporation, tai-6990PH) was spin-coated on the obtained bottom anti-reflective coating. The formed resist layer was subjected to soft baking at 120°C for 60 seconds on a vacuum hot plate, and then was imagewise exposed to 193 nm radiation by a photomask. After post-exposure baking at 130°C for 60 seconds, the resist layer was developed at 25-40°C for 30-60 seconds using a 2.38 wt% TMAH aqueous solution, and the development results are shown in Table 3.

[0112] Table 3

[0113]

[0114]

[0115] Note: Regarding the cross-sectional shape of the pattern: A indicates that both the photoresist and the bottom anti-reflective coating show a rectangular side surface perpendicular to the substrate surface; B indicates that both the photoresist and the bottom anti-reflective coating show a side surface which is not perpendicular to, but slightly inclined to the substrate surface, but in practice there is no problem; C indicates that both the photoresist and the bottom anti-reflective coating show a side surface which is a tessellation shape with respect to the substrate surface.

Claims

1. A method for producing a bottom antireflective coating, characterized by, The preparation method comprises the following steps: casting a bottom anti-reflective coating composition on a semiconductor substrate, baking to obtain a bottom anti-reflective coating, The composition of the bottom anti-reflective coating comprises a terpolymer, a solvent and a photoacid generator, wherein the terpolymer is prepared by the following preparation method: The monomer as shown in formula (A), monomer B and the monomer as shown in formula (C) are subjected to polymerization reaction in a solvent in the presence of a crosslinking agent as shown in formula (L) and an initiator to obtain a terpolymer; the monomer B is hydroxyethyl methacrylate and / or hydroxypropyl methacrylate; The amount of the monomer as shown in formula (A) is 500-800 parts by weight, the amount of the monomer B is 500-800 parts by weight, and the amount of the monomer as shown in formula (C) is 500-800 parts by weight; A: C: L:

2. The production method according to claim 1, wherein It satisfies one or more of the following conditions: (1) the tool for casting is a spin coater or a coating machine, preferably a spin coater; (2) the semiconductor substrate is one of a silicon / silica coated substrate, a silicon nitride substrate, a silicon wafer substrate, a glass substrate or an ITO substrate, preferably a silicon wafer substrate; (3) the baking temperature is 80-250℃, preferably 100-250℃, and most preferably 190℃; (4) the baking time is 0.3-5 minutes, preferably 0.5-2 minutes, and most preferably 1 minute.

3. The method of preparing a bottom antireflective coating of claim 1, wherein, It satisfies one or more of the following conditions: (1) the weight average molecular weight of the terpolymer is 2000-5000000, preferably 3000-100000, for example 6851, 6351, 6952, 5988, 6432 or 6137; (2) the amount of the crosslinking agent as shown in formula (L) is 100-300 parts by weight, preferably 100, 200 or 300 parts by weight; (3) the initiator is one of 2,2'-azobis(isobutyronitrile), 2,2'-azobis-dimethyl-(2-methylpropionate), 2,2'-azobis-(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2-cyclopropylpropionitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 1,1'-azobis(cyclohexanecarbonitrile), benzoyl peroxide, tert-butyl peroxybenzoate, di-tert-butyl-diperoxyphthalate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxy pivalate, tert-amyl peroxy pivalate and butyllithium, preferably 2,2'-azobis(isobutyronitrile); (4) the amount of the initiator is 1-10wt%, the percentage is the weight of the initiator to the total weight of all monomers, preferably 4-6wt%, further preferably 4wt%, 4.8wt%, 5wt% and 6wt%; (5) the amount of the monomer as shown in formula (A) is 500, 650 or 800 parts by weight; (6) the amount of the monomer as shown in formula (B) is 500, 650 or 800 parts by weight; (7) the amount of the monomer as shown in formula (C) is 500, 650 or 800 parts by weight; (8) the solvent is an organic solvent, preferably one or more of aromatic hydrocarbon solvents, ether solvents, ketone solvents, amide solvents, sulfoxide solvents and ester solvents; the aromatic hydrocarbon solvents are preferably toluene and / or benzene; the ether solvents are preferably tetrahydrofuran; the ketone solvents are preferably methyl amyl ketone; the amide solvents are preferably N,N'-dimethylformamide; the sulfoxide solvents are preferably dimethyl sulfoxide; the ester solvents are preferably ethyl lactate and / or propylene glycol monomethyl ether acetate; the organic solvents are more preferably amide solvents and ketone solvents, such as N,N'-dimethylformamide and methyl amyl ketone.

4. The method of making a bottom antireflective coating of claim 1, wherein, The preparation method of the terpolymer comprises the following steps: (1) preheating the solvent; (2) mixing the monomer as shown in formula (A), the monomer B, the monomer as shown in formula (C), the crosslinking agent as shown in formula (L), the initiator and the solvent to obtain a mixed solution; (3) adding the mixed solution into the preheated solvent to perform a polymerization reaction; Steps (1) and (2) are not in sequence.

5. The method of producing a bottom antireflective coating according to claim 4, wherein It meets one or more of the following conditions: (1) in the preparation method of the terpolymer, in step (1), the preheating temperature is 80-100°C, preferably 90°C; (2) in the preparation method of the terpolymer, in step (1), the amount of the solvent is 600-1000 parts by weight, preferably 1000 parts by weight; if two or more solvents are contained at the same time, the amounts of different solvents are preferably the same; (3) in the preparation method of the terpolymer, in step (1), the solvent is purged with nitrogen, and the purging time is preferably 20-50 minutes, more preferably 30 minutes; (4) in the preparation method of the terpolymer, in step (2), the amount of the solvent is 6000-10000 parts by weight, preferably 7000 parts by weight; if two or more solvents are contained at the same time, the amounts of different solvents are preferably the same; (5) in the preparation method of the terpolymer, in step (2), the mixed solution is purged with nitrogen; the purging time is preferably 30 minutes; (6) in the preparation method of the terpolymer, in step (3), the mixed solution is added into the preheated solvent by peristaltic pump; the adding time is preferably 2.5 hours; (7) in the preparation method of the terpolymer, in step (3), the polymerization reaction time is 5-7 hours, more preferably 6 hours; (8) in the preparation method of the terpolymer, the post-treatment preferably comprises the following steps: cooling, adding an organic solvent into the reaction solution, removing the supernatant, dissolving the remaining reaction mixture in tetrahydrofuran, pouring the obtained solution into water, filtering and drying; preferably, in the post-treatment of the polymerization reaction, one or more of the following conditions are met: (a) the cooling is cooling the reaction solution to room temperature; (b) the organic solvent is a poor solvent for the polymer but a good solvent for the polymer solvent, preferably n-hexane or n-heptane, most preferably n-heptane; the amount of the organic solvent is preferably 6000 parts by weight; (c) the water is preferably used in an amount of 100,000 parts by weight; (d) the filtration is preferably reduced pressure filtration; (e) the drying is preferably performed in a vacuum oven overnight, and the temperature of the vacuum oven is preferably set to 45°C.

6. The bottom antireflective coating of claim 1, wherein which satisfies one or more of the following conditions: (1) the solvent in the composition of the bottom antireflective coating is one or more of an ether solvent, an ester solvent, an alcohol solvent, an aromatic hydrocarbon solvent, a ketone solvent, and an amide solvent; the ether solvent is preferably one or more of propylene glycol monobutyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and propylene glycol monomethyl ether; the ester solvent is preferably one or more of propylene glycol monobutyl ether acetate, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether acetate, propylene glycol propyl ether acetate, 2-hydroxypropionic acid ethyl ester, 2-hydroxy-2-methyl-propionic acid ethyl ester, ethoxyacetic acid ethyl ester, hydroxyacetic acid ethyl ester, 2-hydroxy-3-methylbutyric acid methyl ester, 3-methoxypropionic acid methyl ester, 3-methoxypropionic acid ethyl ester, 3-ethoxypropionic acid ethyl ester, 3-ethoxypropionic acid methyl ester, pyruvic acid methyl ester, pyruvic acid ethyl ester, acetic acid ethyl ester, acetic acid butyl ester, lactic acid ethyl ester, and lactic acid butyl ester; the alcohol solvent is preferably propylene glycol; the aromatic hydrocarbon solvent is preferably toluene and / or xylene; the ketone solvent is preferably one or more of methyl ethyl ketone, cyclopentanone, and cyclohexanone; the amide solvent is preferably one or more of N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; and the solvent is more preferably propylene glycol monobutyl ether and / or propylene glycol monobutyl ether acetate; (2) the solvent in the composition of the bottom antireflective coating is preferably used in an amount of 1,000 to 2,500 parts by weight, more preferably 1,200 to 2,000 parts by weight, for example, 1,200, 1,500, or 2,000, further preferably 1,500 to 1,800 parts by weight; (3) the photoacid generator in the composition of the bottom antireflective coating is one or more of an onium salt compound, a sulfone imide derivative, and a disulfonyl diazomethane compound; The onium salt compound is preferably an iodonium salt compound, a sulfonium salt compound, or a cross-linkable onium salt compound; the iodonium salt compound is preferably one or more of diphenyl iodonium hexafluorophosphate, diphenyl iodonium triflate, diphenyl iodonium nonafluoro-n-butane sulfonate, diphenyl iodonium perfluoro-n-octane sulfonate, diphenyl iodonium camphor sulfonate, bis(4-tert-butylphenyl) iodonium camphor sulfonate, and bis(4-tert-butylphenyl) iodonium triflate; the sulfonium salt compound is preferably one or more of triphenyl sulfonium hexafluoroantimonate, triphenyl sulfonium nonafluoro-n-butane sulfonate, triphenyl sulfonium camphor sulfonate, and triphenyl sulfonium triflate, more preferably triphenyl sulfonium hexafluoroantimonate and / or triphenyl sulfonium triflate; and the cross-linkable onium salt compound is preferably one or more of bis(4-hydroxyphenyl)(phenyl) sulfonium triflate, bis(4-hydroxyphenyl)(phenyl) sulfonium 1,1,2,2,3,3,4,4,4-nonafluoro-butane-1-sulfonate, phenyl bis(4-(2-(vinyloxy)ethoxy)-phenyl) sulfonium 1,1,2,2,3,3,4,4-octafluoro-butane-1,4-disulfonate, and tri(4-(2-(vinyloxy)ethoxy)-phenyl) sulfonium 1,1,2,2,3,3,4,4-octafluoro-butane-1,4-disulfonate. The sulfone imide derivative is preferably one or more of N-(trifluoromethanesulfonyloxy) succinimide, N-(fluoro-n-butanesulfonyloxy) succinimide, N-(camphor sulfonyloxy) succinimide, and N-(trifluoromethylsulfonyloxy) naphthalene dicarboximide. The disulfonyl diazomethane compound is preferably one or more of bis(trifluoromethylsulfonyl) diazomethane, bis(cyclohexylsulfonyl) diazomethane, bis(benzenesulfonyl) diazomethane, bis(p-toluenesulfonyl) diazomethane, bis(2,4-dimethylbenzenesulfonyl) diazomethane, and methylsulfonyl-p-toluenesulfonyl diazomethane. (4) In the composition of the bottom antireflective coating, the photoacid generator is used in an amount of 1 to 20 parts by weight, for example, 1, 10, or 20 parts by weight. (5) In the composition of the bottom antireflective coating, the terpolymer is used in an amount of 95 to 110 parts by weight, for example, 100 parts by weight. (6) The composition of the bottom antireflective coating further contains other additional components, which include polymers other than the polymers described above, surfactants, and smoothing agents.

7. The method of making a bottom antireflective coating of claim 1, wherein, The composition of the bottom antireflective coating is prepared by mixing the components of the composition described in claim 1.

8. The method of producing a bottom antireflective coating according to claim 7, wherein The mixing is preferably performed by stirring at room temperature for 30 minutes. The mixing is further followed by a filtration step, which can be performed using a filter having a pore size of 0.2 to 0.05 μm, more preferably 0.05 μm.

9. A bottom antireflective coating characterized in that, It is prepared by the preparation method described in any one of claims 1 to 7.

10. A method of forming a photoresist pattern on a bottom antireflective coating, comprising: It comprises the following steps: S1: coating a photoresist on the bottom antireflective coating as claimed in any one of claims 1 to 9; S2: soft baking; S3: exposure; S4: baking; S5: development; Preferably, it satisfies one or more of the following conditions: (1) the photoresist is a positive photoresist, a negative photoresist or a negative tone development photoresist, preferably a positive photoresist, for example a 248 nm positive photoresist or a 193 nm positive photoresist; (2) the soft baking temperature is 100 to 140°C, more preferably 120°C, and the soft baking time is 0.5 to 2 minutes, preferably 60 seconds; (3) the exposure light is 13.5 to 248 nm light, preferably KrF excimer laser light, ArF excimer laser light or extreme UV light; (4) the baking temperature is 80 to 150°C, preferably 100 to 140°C, most preferably 130°C; (5) the baking time is 0.3 to 5 minutes, preferably 0.5 to 2 minutes, most preferably 60 seconds; (6) the development is performed using a developing solution, the developing solution is an alkaline developing solution, preferably an aqueous solution of an alkali metal hydroxide, an aqueous solution of a tertiary ammonium hydroxide or an aqueous solution of an amine; the aqueous solution of an alkali metal hydroxide is preferably an aqueous solution of potassium hydroxide or an aqueous solution of sodium hydroxide; the aqueous solution of a tertiary ammonium hydroxide is preferably an aqueous solution of tetramethylammonium hydroxide, an aqueous solution of tetraethylammonium hydroxide or an aqueous solution of choline; the aqueous solution of an amine is preferably an aqueous solution of ethanolamine, an aqueous solution of propylamine or an aqueous solution of ethylenediamine; the developing solution is more preferably an aqueous solution of 2.38 wt% tetramethylammonium hydroxide; (7) the developing solution can also contain a surfactant; (8) the developing solution temperature is 5 to 50°C, preferably 25 to 40°C; (9) the developing time is 10 to 300 seconds, preferably 30 to 60 seconds.

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