Photolithography using silicon photoresist

Abstract

1. A method of forming a pattern, comprising: providing a substrate on which a pattern is to be formed; forming a silicon photoresist layer on the substrate; exposing the silicon photoresist to radiation at an activating wavelength; hardening the silicon photoresist; developing the hardened silicon photoresist to remove portions of the photoresist exposed to radiation at the activating wavelength; and etching the substrate to form the pattern.

Description

[Technical Field]

[0001] The present invention relates to photolithography for microelectronic fabrication. [Background technology]

[0002] In photolithography, a photoresist is applied to a substrate containing a layer in which it is desired to form features such as lines or via holes. The photoresist is image-wise exposed to radiation at an activating wavelength, hardened, and developed, thereby removing the unhardened portions and leaving a pattern of hardened portions. Development can be accomplished by applying a developer solution to remove the unhardened portions. Commonly used photoresists include hydrocarbon-based polymer materials. Hydrocarbon photoresists are typically applied by spin-coating onto a bare substrate, a thin organic bottom antireflective coating (BARC), or a thick organic BARC that is bonded to a thin silicon BARC (sometimes called a hard mask).

[0003] BARCs are desirable because they reduce the reflection of radiation from the substrate, which can adversely affect the accuracy of the image formed. Improved methods for forming patterns of lines or via holes remain needed. Summary of the Invention

[0004] The present specification discloses a method of forming a pattern, the method comprising the steps of providing a substrate on which a pattern is to be formed, forming a silicon photoresist layer on the substrate, exposing portions of the silicon photoresist to radiation at an activating wavelength, hardening the silicon photoresist, developing the hardened silicon photoresist to remove portions of the photoresist exposed to radiation at the activating wavelength, and etching the substrate to form the pattern. [Brief explanation of the drawings]

[0005] [Figure 1] 1(a)-1(c) illustrate a prior art method of forming a pattern using a hydrocarbon photoresist and a hydrocarbon BARC. [Figure 2] 2(a)-2(d) show prior art methods of forming patterns using hydrocarbon photoresists and combinations of silicon-containing and hydrocarbon-containing BARCs. [Figure 3] 3(a)-3(c) show an example of a method for forming a pattern using a hydrocarbon-containing BARC and a silicon photoresist. [Figure 4] 4(a) to 4(c) show an example of a method for forming a pattern using a silicon BARC and a silicon photoresist. [Figure 5] 5(a)-5(c) show an example of a method for forming a pattern using a thick hydrocarbon BARC and silicon photoresist. [Figure 6] 6(a) to 6(c) show an example of a method for forming a pattern on a silicon substrate using a silicon photoresist. [Figure 7] 7(a)-7(c) show an example of a method for forming a pattern on a silicon substrate using a photosensitive hydrocarbon BARC and a silicon photoresist. DETAILED DESCRIPTION OF THE INVENTION

[0006] Reference is now made to the drawings, which illustrate exemplary embodiments and in which like elements are numbered the same.

[0007] In photolithography, bottom antireflective coatings (BARCs) contain chromophores that strongly absorb radiation at activating wavelengths. BARCs can reduce the reflection of radiation from the substrate, which can adversely affect the accuracy of the resulting image. Additionally, BARCs can control the adhesion of photoresist to the substrate.

[0008] A BARC may be a hydrocarbon-based material (also called a hydrocarbon-containing material or hydrocarbon BARC). However, although "hydrocarbon" typically refers to a compound having only C and H atoms, as used herein, "hydrocarbon group," "hydrocarbon-containing," or "hydrocarbon BARC" may include compounds having only C and H atoms, compounds containing C atoms, H atoms, and heteroatoms such as O, N, or S, or combinations thereof.

[0009] The hydrocarbon-containing BARC comprises a hydrocarbon-containing polymer that can be cured to ensure that the hydrocarbon BARC is resistant to photoresist developers. This curing occurs, for example, at about 200°C. Due to the high curing temperature, chromophores are preferably grafted onto the polymer chains to avoid migration (e.g., outgassing) during high-temperature curing. For example, as shown in FIG. 1(a), a thin cured hydrocarbon BARC 11 is formed on a substrate comprising a polycrystalline silicon layer 13 on silicon oxide 14. A hydrocarbon photoresist layer is applied to the hydrocarbon BARC 11, exposed to radiation at an activating wavelength, and developed to form a patterned hydrocarbon photoresist 16.

[0010] After developing the photoresist, the exposed BARC is at least partially removed by reactive ion etching (referred to herein as "RIE"). The substrate can also be patterned by etching (e.g., RIE). As shown in FIG. 1(b), the hydrocarbon BARC 11 is etched using RIE to expose the polysilicon layer 13. Next, as shown in FIG. 1(c), the polysilicon layer 13 is etched using RIE to form a pattern protected by the hydrocarbon photoresist 16, and the remaining photoresist 16 and hydrocarbon BARC 11 are removed. The remaining photoresist can also be removed using a stripper.

[0011] The lack of etch selectivity between hydrocarbon photoresist and hydrocarbon BARC limits the effective use of hydrocarbon photoresist and thick hydrocarbon BARC layers. Therefore, when a thick hydrocarbon BARC is used, an additional thin silicon BARC (also called a hard mask) is typically also used. For example, as shown in Figure 2(a), hydrocarbon photoresist is applied, exposed, and developed to form a hydrocarbon photoresist pattern 16 on a stack consisting of, from bottom to top, metal 15, silicon oxide 14, thick hydrocarbon BARC 11, and thin silicon BARC 12. As shown in Figure 2(b), silicon BARC 12 is etched by RIE, and the hydrocarbon photoresist is removed. As shown in Figure 2(c), hydrocarbon BARC 11 is etched using the silicon BARC as a mask, and the silicon BARC is removed. As shown in Figure 2(d), a pattern is etched in silicon oxide 14 using the hydrocarbon BARC 11 as a mask, and the hydrocarbon BARC 11 is removed.

[0012] Due to insufficient etching resistance, hydrocarbon photoresists cannot be effectively used alone with silicon-containing BARC. Although silicon-containing hard masks have been disclosed, for example, see US8911932, US8728710, CN102236253, and JP6144000, improved methods for simplifying and / or enhancing photolithography processes are desired.

[0013] To address these and other drawbacks, the method disclosed herein includes providing a substrate containing a portion where a pattern is desired to be formed. Silicon photoresist is applied to the substrate, imagewise exposed to radiation at an activating wavelength, cured, and developed to remove the exposed portions of the silicon photoresist. The activating wavelength radiation may have a wavelength in the range of 10 nm to 400 nm, e.g., 13.5 nm, 193 nm, 248 nm, or 365 nm. The development step can directly expose a portion of the substrate (see, e.g., FIG. 6). Alternatively, a BARC can be formed on the substrate before applying the silicon photoresist. In this case, development of the photoresist exposes the BARC, which is then further etched (e.g., using reactive ion etching, RIE) to expose a portion of the substrate (see, e.g., FIGS. 3-5 and 7). Once the substrate is exposed, a pattern can be etched into the substrate (e.g., using RIE) using the silicon photoresist and / or the intervening BARC as a mask.

[0014] The substrate may include a metal, a semiconductor, a dielectric material, or a combination of two or more thereof. For example, the substrate may include a semiconductor material such as Si, SiGe, SiGeC, SiC, GaAs, InAs, InP, or other III / V or II / VI compound semiconductors. The substrate may include a process wafer, such as a silicon wafer or a wafer produced at various steps of a semiconductor manufacturing process, such as an integrated semiconductor wafer. The substrate may include multiple layers or may be a single layer. The substrate may include a layered substrate, such as Si / SiGe, Si / SiC, silicon-on-insulator (SOI), silicon germanium-on-insulator (SGOI), or the like. The substrate may include silicon, polycrystalline silicon, silicon dioxide or aluminum-aluminum oxide microelectronic wafers, gallium arsenide, silicon carbide, ceramics, quartz, metal, or a combination of two or more thereof. For example, the substrate may include a polycrystalline silicon layer on a silicon oxide layer. As another example, the substrate may include silicon oxide on a metal layer. As another example, the substrate can include, consist essentially of, or consist of a silicon substrate. When a substantially bare silicon substrate is used, the silicon substrate can be surface treated before applying the silicon photoresist. For example, the silicon substrate can be treated with an adhesion promoter such as a silylating agent (e.g., an alkylsilylamine such as bis(trimethylsilyl)amine, also known as hexamethyldisilazane or HMDS).

[0015] A silicon photoresist composition includes a silicon-containing resin, a catalyst that can catalyze the condensation reaction of the silicon-containing resin but is deactivated in the presence of acid, losing its ability to catalyze the condensation reaction, and a photoacid generator. This catalyst is also called a condensation catalyst or a curing catalyst. Therefore, when a coated area of the silicon photoresist composition is exposed to radiation of an activating wavelength, acid is generated and the catalyst is deactivated. Curing then occurs in the unexposed areas. The exposed areas are then removed by development with an appropriate developer. Therefore, the silicon photoresist may be a positive photoresist.

[0016] The silicon-containing polymer resins can be prepared with one or more monomers having the following molecular structures or a combination of two or more of these:

[0017] [ka]

[0018] Each occurrence of R is independently hydrogen or an alkyl group of 1 to 4 carbon atoms, preferably 1 to 3 carbon atoms, and more preferably 1 or 2 carbon atoms. Preferably, R is an alkyl group of 1 or 2 carbon atoms. Each occurrence of R is independently a monovalent hydrocarbon group having 1 to 30 carbon atoms and, optionally, 1 to 5 heteroatoms selected from N, O, P, S, or a combination of two or more thereof. Combinations containing at least one of the above can be used. For example, each R may be an alkyl group having 1 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, an alkene group having 2 to 30 carbon atoms, or an alicyclic group having 3 to 30 carbon atoms. Each optionally includes -O-, -CO-, -OCO-, -COO-, or -OCOO- as part of its structure. Each R may be further independently substituted with one or more epoxy groups. Preferably, R1 is an alkyl group having 1 or 2 carbon atoms to provide the cured resin with a silicon content of greater than 42 wt. % based on the total weight of the cured resin.

[0019] Examples of preferred monomers include methyltrimethoxysilane, tetraethoxysilane, tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, isopropyltrimethoxysilane, isopropyltriethoxysilane, butyltrimethoxysilane, butyltriethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, cyclopentyltrimethoxysilane, cyclopentyltriethoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, and cyclohexenyl Examples of the silane include trimethoxysilane, cyclohexenyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, benzyltrimethoxysilane, benzyltriethoxysilane, phenethyltrimethoxysilane, phenethyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, methylethyldimethoxysilane, methylethyldiethoxysilane, dipropyldimethoxysilane, dibutyldimethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, trimethylmethoxysilane, dimethylethylmethoxysilane, dimethylphenylmethoxysilane, dimethylbenzylmethoxysilane, dimethylphenethylmethoxysilane, and the like, or a combination of two or more thereof. Combinations comprising at least one of the above may be used.

[0020] Polymerization of the monomers can be carried out in an organic solvent. Exemplary organic solvents used in polymerization include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, acetone, acetonitrile, tetrahydrofuran, toluene, hexane, ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl normal pentyl ketone, butylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, butylene glycol monoethyl ether, propylene glycol monoethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene ...ethyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl Examples of suitable organic solvents include ethylene glycol monoethyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, propylene glycol mono-tert-butyl ether acetate, γ-butyrolactone, and the like, or combinations of two or more thereof. Combinations comprising at least one of the above may also be used. The organic solvent may be propylene glycol monomethyl ether or propylene glycol methyl ether acetate.

[0021] Polymerization of the monomers can be carried out in the presence of one or more polymerization catalysts. The polymerization catalyst can be an acid catalyst. Exemplary acid catalysts include organic acids such as formic acid, acetic acid, oxalic acid, maleic acid, methanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid, and the like, or combinations of two or more thereof; or inorganic acids such as hydrofluoric acid, hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, perchloric acid, phosphoric acid, and the like, or combinations of two or more thereof. Combinations comprising at least one of the above can also be used. The acid catalyst can be acetic acid. The acid catalyst can be used in any suitable amount, such as 1 wt% to 10 wt% (weight %), 2 to 8 wt%, or 3 to 7 wt%, based on the total weight of the reactor contents.

[0022] The polymerization is carried out at a temperature of 0°C to 110°C, 20°C to 110°C, 50°C to 110°C, or 80°C to 110°C.

[0023] Volatile alkanols formed during the reaction can be removed by distillation as the reaction proceeds. The distillate may also contain catalyst, water, and / or solvent. Nitrogen gas flowing through the reactor contributes to the distillation. Removal of the volatile alkanols can be carried out during or after the polymerization reaction.

[0024] The silicon-containing polymer resin thus formed can include polysiloxane, polysilsesquioxane, or a combination thereof.For example, the silicon-containing polymer resin can include both polysiloxane and polysilsesquioxane.The silicon-containing polymer resin can include a crosslinked or network structure.The network structure can include a series of complex and diverse molecular structures of polysiloxane and polysilsesquioxane.For example, the network structure can include a variety of structures such as the following molecular structures:

[0025] [ka]

[0026] wherein each R and R1 are independently as defined herein. However, the above structure is not necessarily an accurate or complete description of the silicon-containing polymer resin. The selected monomers and polymerization process provide the most accurate description of the polymer.

[0027] The weight average molecular weight (Mw) of the silicon-containing polymer resin before curing may be 1,000 to 50,000 g / mol, 1,500 to 30,000 g / mol, 2,000 to 20,000 g / mol, or 3,000 to 10,000 g / mol. The weight average molecular weight can be determined by gel permeation chromatography (GPC) using polystyrene standards, as described in Williams and Ward, J. Polymer. Sci., Polymer. Letters, 6, 621 (1968), the entire contents of which are incorporated herein by reference.

[0028] Exemplary silicon-containing resins include siloxanes, silsesquioxanes, polysiloxanes, or polysilsesquioxanes, such as methylsiloxane, methylsilsesquioxane, phenylsiloxane, phenylsilsesquioxane, methylphenylsiloxane, methylphenylsiloxane, methylphenylsilsesquioxane, dimethylsiloxane, diphenylsiloxane, methylphenylsiloxane, polyphenylsilsesquioxane, polyphenylsiloxane, polymethylphenylsiloxane, polymethylphenylsilsesquioxane, substituted polymethylsilsesquioxane, or combinations of two or more thereof. Combinations comprising at least one of the above can also be used. These resins can be substituted or unsubstituted.

[0029] The amount of silicon-containing resin that can be included in the photoresist precursor composition is 0.5 wt % to 40 wt %, 1 wt % to 30 wt %, or 2 wt % to 20 wt %, based on the total weight of the dielectric precursor composition, corresponding to a film thickness of 10 nm to 2 μm at a typical spin-coating speed (e.g., 500 rpm to 2000 rpm).

[0030] Examples of catalysts (curing catalysts or condensation catalysts) in silicon photoresist compositions include methylamine, ethylamine, propylamine, butylamine, ethylenediamine, hexamethylenediamine, dimethylamine, diethylamine, ethylmethylamine, trimethylamine, triethylamine, tripropylamine, tributylamine, cyclohexylamine, dicyclohexylamine, monoethanolamine, diethanolamine, dimethylmonoethanolamine, monomethyldiethanolamine, triethanolamine, hexamethylenetetramine, aniline, N,N-dimethylaniline, N, Quaternary ammonium and / or amine compounds such as N-dimethylpyridin-4-amine, pyrrole, piperazine, pyrrolidine, piperidine, benzyltriethylammonium chloride (BTEAC), tetramethylammonium chloride (TMAC), guanidine carbonate, tetramethylammonium hydroxide (TMAH), tetramethylammonium acetate (TMAA), tetrabutylammonium hydroxide (TBAH), tetrabutylammonium acetate (TBAA), cetyltrimethylammonium acetate (CTAA), tetramethylammonium nitrate (TMAN), or combinations of two or more thereof. Combinations comprising at least one of the above may be used.

[0031] The amount of the curing catalyst may be 0.0005 wt% to 0.2 wt%, or 0.001 wt% to 0.05 wt%, based on the total weight of the dielectric precursor composition. The amount of the catalyst may be 0.045 wt% to 4 wt%, or 0.01 wt% to 0.5 wt%, based on the total weight of the silicon-containing polymer resin.

[0032] The photoacid generator is preferably a compound that generates an organic acid upon irradiation with actinic rays or radiation. The photosensitive wavelength of the photoacid generator is preferably, for example, 10 nm to 450 nm, or 300 nm to 450 nm. In other words, the photoacid generator is preferably a compound that generates an acid in response to actinic rays in the above wavelength range. The pKa of the acid generated by the photoacid generator is preferably 4.0 or less, more preferably 3.0 or less.

[0033] Examples of photoacid generators include onium salts, triazine compounds (preferably halomethylated triazine compounds, more preferably trichloromethyl-s-triazine compounds), oxime sulfonate compounds, bissulfonyldiazomethane compounds, imidosulfonate compounds, diazodisulfone compounds, disulfone compounds, or nitrobenzyl sulfonate compounds (preferably o-nitrobenzyl sulfonate compounds). Preferred photoacid generators are sulfonium salts or iodonium salts, and more preferred are compounds of sulfonium cations with sulfonates or methides, or compounds of iodonium cations with sulfonates. Exemplary sulfonium cations include triphenylsulfonium and tris(4-tert-butoxyphenyl)sulfonium. Exemplary sulfonates include trifluoromethanesulfonate and nonafluorobutane-1-sulfonate. Exemplary methides include tris(trifluoromethyl)methide. Exemplary iodonium cations include iodonium cations with aryl groups, such as diphenyliodonium and bis(4-tert-butylphenyl)iodonium. Exemplary sulfonates include trifluoromethanesulfonate and nonafluorobutane-1-sulfonate. Combinations comprising at least one of the above can be used.

[0034] Exemplary photoacid generators include, for example, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium trifluoroacetate, (4-methoxyphenyl)diphenylsulfonium trifluoromethanesulfonate, (4-methoxyphenyl)diphenylsulfonium trifluoroacetate, [4-(phenylthio)phenyl]diphenylsulfonium trifluoromethanesulfonate, [4-(phenylthio)phenyl]diphenylsulfonium trifluoroacetate, diphenyliodonium trifluoromethanesulfonate, trifluoro (p-tert-butoxyphenyl)phenyliodonium trifluoromethanesulfonate, diphenyliodonium p-toluenesulfonate, (p-tert-butoxyphenyl)phenyliodonium p-toluenesulfonate, triphenylsulfonium trifluoromethanesulfonate, (p-tert-butoxyphenyl)diphenylsulfonium trifluoromethanesulfonate, bis(p-tert-butoxyphenyl)phenylsulfonium trifluoromethanesulfonate, tris(p-tert-butoxyphenyl)trifluoromethanesulfonate (phenyl)sulfonium, triphenylsulfonium p-toluenesulfonate, (p-tert-butoxyphenyl)diphenylsulfonium p-toluenesulfonate, bis(p-tert-butoxyphenyl)phenylsulfonium p-toluenesulfonate, tris(p-tert-butoxyphenyl)sulfonium p-toluenesulfonate, triphenylsulfonium nonafluoro-1-butanesulfonate, triphenylsulfonium 1-butanesulfonate, trimethylsulfonium trifluoromethanesulfonate, p-toluenesulfonic acid Trimethylsulfonium, cyclohexylmethyl(2-oxocyclohexyl)sulfonium trifluoromethanesulfonate, cyclohexylmethyl(2-oxocyclohexyl)sulfonium p-toluenesulfonate, dimethylphenylsulfonium trifluoromethanesulfonate, dimethylphenylsulfonium p-toluenesulfonate, dicyclohexylphenylsulfonium trifluoromethanesulfonate, dicyclohexylphenylsulfonium p-toluenesulfonate, trinaphthylsulfonium trifluoromethanesulfonate,Cyclohexylmethyl(2-oxocyclohexyl)sulfonium trifluoromethanesulfonate, (2-norbornyl)methyl(2-oxocyclohexyl)sulfonium trifluoromethanesulfonate, Ethylenebis[methyl(2-oxocyclopentyl)sulfonium trifluoromethanesulfonate], 1,2'-naphthylcarbonylmethyltetrahydrothiophenium triflate, Diphenyliodonium trifluoroacetate, Diphenyliodonium trifluoromethanesulfonate, Trifluoromethanesulfonic acid (4-methyl) Onium salts such as (4-methoxyphenyl)phenyliodonium trifluoroacetate, (4-methoxyphenyl)phenyliodonium trifluoroacetate, [4-[(2-hydroxytetradecyl)oxy]phenyl]phenyliodonium trifluoromethanesulfonate, [4-[(2-hydroxytetradecyl)oxy]phenyl]phenyliodonium hexafluoroantimonate, [4-[(2-hydroxytetradecyl)oxy]phenyl]phenyliodonium p-toluenesulfonate, or combinations of two or more thereof may be used. Combinations comprising at least one of the above may also be used.

[0035] Exemplary diazomethane compounds include bis(phenylsulfonyl)diazomethane, bis(p-toluenesulfonyl)diazomethane, bis(xylenesulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, bis(cyclopentylsulfonyl)diazomethane, bis(n-butylsulfonyl)diazomethane, bis(isobutylsulfonyl)diazomethane, bis(isoamylsulfonyl)diazomethane, 1-tert-amylsulfonyl-1-(tert-butylsulfonyl)diazomethane, and the like, or combinations of two or more thereof. Combinations comprising at least one of the above can be used.

[0036] Exemplary triazine compounds include 2-(3-chlorophenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4-methylthiophenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4-methoxy-β-styryl)-4,6-bis(trichloromethyl)-s-triazine, 2-piperonyl-4,6-bis(trichloromethyl)-s-triazine, 2- [2-(furan-2-yl)vinyl]-4,6-bis(trichloromethyl)-s-triazine, 2-[2-(5-methylfuran-2-yl)vinyl]-4,6-bis(trichloromethyl)-s-triazine, 2-[2-(4-diethylamino-2-methylphenyl)vinyl]-4,6-bis(trichloromethyl)-s-triazine, 2-(4-methoxynaphthyl)-4,6-bis(trichloromethyl)-s-triazine, etc., or a combination of two or more thereof. Combinations comprising at least one of the above may be used.

[0037] Exemplary imide sulfonate compounds include trifluoromethylsulfonyloxy-bicyclo-[2.2.1]-hept-5-ene-dicarboximide, succinimide trifluoromethylsulfonate, phthalimide trifluoromethylsulfonate, N-hydroxynaphthalimide methylsulfonate, N-hydroxy-5-norbornene-2,3-dicarboximide propylsulfonate, and the like, or a combination of two or more thereof. Combinations comprising at least one of the above can be used.

[0038] A specific example of a photoacid generator is 2-(4-methoxyphenyl)([((4-methylphenyl)sulfonyl)oxy]imino)acetonitrile.

[0039] The content of the photoacid generator is preferably 0.01 wt % to 3 wt %, 0.05 wt % to 2 wt %, 0.1 wt % to 1 wt %, or 0.2 wt % relative to the total solid content of the composition.

[0040] The molar ratio of the photoacid generator to the catalyst may be, for example, 0.5:1 to 10:1, 0.5:1 to 5:1, or 0.5:1 to 1.5:1.

[0041] The silicon photoresist may have a high silicon content, for example, greater than 35 wt%, greater than 38 wt%, greater than 39 wt%, greater than 40 wt%, greater than 41 wt%, or at least 42 wt% silicon, and not more than 46 wt%, or not more than 45 wt%, based on the total weight of the photoresist composition.

[0042] Silicon photoresists can offer better protection against ion bombardment than hydrocarbon photoresists, a feature that is particularly beneficial when the photoresist is applied to bare (treated or untreated) silicon substrates.

[0043] The step of forming a layer of silicon photoresist on a substrate includes applying to the substrate a coating composition that includes a silicon-containing resin, a catalyst, a photoacid generator, optional additives, and a coating solvent.

[0044] Exemplary paint solvents include non-hydrocarbon solvents such as ketones, e.g., acetone, diethyl ketone, methyl ethyl ketone, etc., alcohols, esters, ethers, amines, etc. Examples of solvents include propylene glycol monomethyl ether (PGME), propylene glycol methyl ether acetate (PGMEA), propylene glycol monopropyl ether (PGPE), and ethyl lactate (EL).

[0045] The coating solvent is included in the composition in an amount of 50 wt% to 99 wt%, 55 wt% to 95 wt%, 60 wt% to 90 wt%, or 65 wt% to 85 wt%, based on the total weight of the dielectric precursor composition.

[0046] Suitable application methods include spin coating, spray coating, etc. The solvent is removed to form a solid layer of the photopatternable dielectric precursor composition.

[0047] Optional additional components of the coating composition include film modifiers to control the diffusion of components in the film, or the like, or a combination of two or more thereof.

[0048] The membrane modifier may be a polymer, oligomer, or non-polymeric compound. The weight-average molecular weight (Mw) of the polymer or oligomer used as the membrane modifier is preferably less than 5,000 g / mol, more preferably less than 2,000 g / mol, as determined, for example, by GPC. The membrane modifier molecules must be small enough to fill the pores of the membrane. The membrane modifier may be a compound containing only C and H, a hydrocarbon, or preferably a silicon-containing compound. At least one hydroxyl group is bonded to each molecule of the membrane modifier. The hydroxyl group can participate in the condensation reaction of the resin membrane. Exemplary hydrocarbon membrane modifiers include polyols such as, for example, polyether diols, glycerin, 2-(hydroxymethyl)-1,3-propanediol, 1,3-dihydroxypropan-2-yl dihydrogen phosphate, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, or combinations of two or more thereof.Examples of branched alkylene glycols include neopentyl glycol, 2,4-diethyl-1,5-pentanediol, 2,4-dibutyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 1-methylethylene glycol, 1-ethylethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, 1,1,1-tris(hydroxymethyl)ethane, 2-hydroxymethyl-1,3-propanediol, 2-ethyl-2-(hydroxymethyl)-1,3-propanediol, 2-hydroxymethyl-2-propyl-1,3-propanediol, 2-hydroxymethyl-1,4-butanediol, 2-hydroxyethyl-2-methyl-1,4-butanediol, 2-hydroxymethyl-2-propyl-1,4-butanediol, 2-ethyl-2-hydroxyethyl-1,4-butanediol, 1,2,3- Butanetriol, 1,2,4-butanetriol, 3-(hydroxymethyl)-3-methyl-1,4-pentanediol, 1,2,5-pentanetriol, 1,3,5-pentanetriol, 1,2,3-trihydroxyhexane, 1,2,6-trihydroxyhexane, 2,5-dimethyl-1,2,6-hexanetriol, tris(hydroxymethyl)nitromethane, 2-methyl-2-nitro-1,3-propanediol, 2-bromo-2-nitro- Examples of suitable membrane modifiers include 1,3-propanediol, 1,2,4-cyclopentanetriol, 1,2,3-cyclopentanetriol, 1,3,5-cyclohexanetriol, 1,3,5-cyclohexanetrimethanol, butane-1,2,3,4-tetrol, 2,2-bis(hydroxymethyl)-1,3-propanediol, pentane-1,2,4,5-tetrol, and the like, or a combination of two or more thereof. The membrane modifier may be 1,1,1-tris(hydroxymethyl)ethane, pentaerythritol, or a combination thereof.Exemplary silicon-containing film modifiers include silanols such as diphenylsilanediol, diisobutylsilanediol, 1,4-bis(dimethylhydroxysilyl)benzene, and 4-vinylphenylsilanediol, or a combination of two or more thereof. The content of the film modifier is 30 wt% or less, preferably 10 wt% or less, of the total weight of the resin. It may be 0.01 wt% to 15 wt% or 0.1 wt% to 10 wt% of the total weight of the resin. The concentration of the film modifier in the composition controls the diffusion lengths of the catalyst, photoacid generator, and quencher. Various film modifiers can be used.

[0049] Removal of the solvent may involve baking (e.g., on a hotplate surface) for 15 to 120 seconds or 30 to 60 seconds at 40 to 120° C., 50 to less than 100° C., or 60 to less than 80° C. This bake step should not be for a time or at a temperature sufficient to cure the silicon-containing resin so that the dried film remains soluble in the developer. Exposure can include exposure to radiation of an activating wavelength. Exposure is imagewise exposure to generate a pattern in the silicon photoresist. Exposure can be through a mask or by direct laser addressing. The wavelength can be, for example, in the range of 10 nm to 400 nm, or can be a specific wavelength such as 365 nm, 248 nm, 193 nm, or 13.5 nm.

[0050] The exposure to light deactivates the catalyst, so that during subsequent curing by heating, the silicon-containing resin precursor cures (e.g., crosslinks) only in the areas not exposed to the radiation. Curing is carried out at temperatures of 60°C to 120°C or 80°C to 111°C for 30 to 120 seconds.

[0051] Silicon photoresists can be developed using organic solvents, especially polar organic solvents, or basic aqueous solutions.Examples of organic solvents include cyclohexanone, propylene glycol monomethyl ether, methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, isoamyl acetate, ethyl methoxyacetate, ethyl ethoxyacetate, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monophenyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monopropyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monophenyl ether acetate, diethylene glycol monobutyl ether acetate, 2-methoxybutyl acetate, 3-methoxybutyl acetate, 4-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-ethyl-3-methoxybutyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol Cholesterol monopropyl ether acetate, 2-ethoxybutyl acetate, 4-ethoxybutyl acetate, 4-propoxybutyl acetate, 2-methoxyamyl acetate, 3-methoxyamyl acetate, 4-methoxyamyl acetate, 2-methyl-3-methoxyamyl acetate, 3-methyl-3-methoxyamyl acetate, 3-methyl-4-methoxyamyl acetate, 4-methyl-4-methoxyamyl acetate, propylene glycol diacetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate, butyl lactate, propyl lactate, ethyl carbonate, propyl carbonate, carbonate Examples of suitable hydroxyl groups include, but are not limited to, butyl, methyl pyruvate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, methyl acetoacetate, ethyl acetoacetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl 3-methoxypropionate, and the like, or combinations of two or more thereof. Combinations comprising at least one of the above may be used.The organic solvent may be propylene glycol monomethyl ether (PGME), propylene glycol methyl ether acetate (PGMEA), ethyl lactate (EL), or cyclohexanone. Examples of alkaline (basic) developers include aqueous solutions of organic or inorganic bases, such as tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, ethanolamine, propylamine, ethylenediamine, choline, potassium hydroxide, sodium hydroxide, or combinations thereof. A specific example of a developer is an aqueous solution of tetramethylammonium hydroxide with a concentration of 2.5 to 25 g / L. Development is carried out under appropriately determined conditions, i.e., a temperature of 5 to 50°C and a development time of 10 to 600 seconds.

[0052] Due to its high resistance to etching, silicon photoresists can be thinner than typical hydrocarbon photoresists. This is beneficial because thinner photoresists allow for more precise patterns. When used with a thin BARC, the photoresist thickness must be sufficient to protect the substrate. The photoresist thickness can range from 2 nm, 5 nm, 10 nm, to 1000 nm, 900 nm, 800 nm, 700 nm, 600 nm, 500 nm, 400 nm, 300 nm, 200 nm, or 100 nm. When used with a thin BARC layer (e.g., about 2-200 nm thick), the silicon photoresist thickness can range from 5 nm, 10 nm, to 1000 nm, 900 nm, 800 nm, 700 nm, 600 nm, 500 nm, 400 nm, 300 nm, or 200 nm. Any suitable combination of the above thicknesses can be used. When using a silicon photoresist with a thick hydrocarbon BARC (e.g., having a thickness of 10 nm to 2000 nm), the silicon photoresist can be thinned in the range of 2 nm, 5 nm, 10 nm, to 200 nm, 100 nm, 90 nm, 80 nm, 70 nm, or 60 nm.

[0053] The hydrocarbon BARC, if used, may comprise a polymer and a light-absorbing group, e.g., a chromophore. The chromophore may be attached to the polymer backbone. Polymers include, for example, epoxy cresol novolac resins, phenol novolac resins, acrylic polymers, polyesters, polysaccharides, polyethers, polyacetates, styrenic polymers (e.g., polystyrene or copolymers of styrene with other monomers such as acrylonitrile), and polyimides. Compositions for forming the hydrocarbon BARC layer include, for example, aminoplasts. The polymer may include a crosslinker such as an epoxy resin, a polyol, an anhydride, a glycidyl ether, a vinyl ether, or a combination thereof. The polymer may include an epoxide ring in the repeat unit. For example, the epoxide group comprises about 20 wt% to 80 wt%, preferably about 20 wt% to 40 wt%, of the total weight of the polymer. The chromophore includes an aromatic or heterocyclic light-absorbing moiety. The chromophore can be covalently bonded to the polymer. For example, the chromophore may have the following chemical formula:

[0054] [ka]

[0055] wherein R is selected from the group consisting of H and substituted and unsubstituted alkyl groups (preferably C1-C8, more preferably C1-C4); and X 1 is an aromatic or heterocyclic light-absorbing moiety. It contains chromophores with phenolic -OH, -COOH, or -NH2 functional groups. Examples of chromophores include phenyl groups, thiophenes, naphthoic acid, anthracene, naphthalene, benzene, chalcones, phthalimides, pamoic acid, acridines, azo compounds, dibenzofurans, or derivatives thereof.

[0056] The hydrocarbon BARC may be uncrosslinked. The hydrocarbon BARC can be applied, for example, by spin coating from a composition containing the hydrocarbon BARC in a solvent, and the solvent can be removed by baking (e.g., at temperatures between 30°C and 150°C, or between 50°C and less than 100°C, for 10 seconds, or 30 seconds to 120 seconds, or 90 seconds).

[0057] The hydrocarbon BARC may be thin (e.g., having a thickness of 2 nm to 200 nm, preferably 5 nm to 60 nm), as shown in, for example, FIG. 3, or thick (e.g., having a thickness of 10 nm to 2000 nm, preferably 20 nm to 1000 nm), as shown in, for example, FIG. 5.

[0058] Silicone BARCs (if used) may include a silicon-containing polymer and a light-absorbing functional group (e.g., a chromophore). For example, the silicone BARC may include an alkylsiloxane oligomer or polymer, an alkylsilsesquioxane oligomer or polymer, an arylsiloxane oligomer or polymer, an arylsilsesquioxane oligomer or polymer, an alkenylsiloxane oligomer or polymer, an alkenylsiloxane oligomer or polymer, or a combination thereof. The alkyl group may have, for example, 1, 2, 3, 4, 5, 6, 7, or 8 carbon atoms. The aryl group may have, for example, 6 to 16 carbon atoms. Examples of chromophores include phenyl, thiophene, naphthoic acid, anthracene, naphthalene, benzene, chalcone, phthalimide, pamoic acid, acridine, azo compounds, dibenzofuran, or derivatives thereof.

[0059] The silicon BARC can be applied, for example, by spin coating from a composition containing the silicon BARC in a solvent, which can be removed by baking (e.g., at temperatures between 30°C and 150°C, or between 50°C and less than 100°C, for 10 seconds, or 30 seconds to 120 seconds, or 90 seconds).

[0060] The silicon BARC may have a thickness in the range of 2 nm to 200 nm, preferably 5 nm to 60 nm.

[0061] As shown in Figures 3(a)-3(c), one example of the method described herein involves forming a thin hydrocarbon BARC 11 (e.g., 2 nm to 200 nm) on a substrate including a polysilicon layer 13 on a silicon oxide layer 14. As shown in Figure 3(a), a silicon photoresist composition is applied, imagewise exposed to radiation at an activating wavelength, cured, and developed to remove the photoresist composition in the exposed areas, leaving behind silicon photoresist 20 that exhibits the pattern in the hydrocarbon BARC 11. As shown in Figure 3(b), the hydrocarbon BARC 11 is etched using the silicon photoresist 20 as a mask, exposing the polysilicon layer 13. As shown in Figure 3(c), the polysilicon layer 13 is etched using the remaining silicon photoresist 20 and the underlying hydrocarbon BARC 11 as a mask.

[0062] As shown in Figures 4(a)-4(c), another example of the method described herein involves forming a thin silicon BARC 12 (e.g., 2 nm to 200 nm) on a substrate including a polysilicon layer 13 on silicon oxide 14. As shown in Figure 4(a), a silicon photoresist composition is applied, imagewise exposed to radiation at an activating wavelength, cured, and developed to remove the photoresist composition in the exposed areas, leaving silicon photoresist 20 that reveals the pattern in the silicon BARC 12. As shown in Figure 4(b), the silicon BARC 12 is etched using the silicon photoresist 20 as a mask to expose the polysilicon layer 13. As shown in Figure 4(c), the polysilicon layer 13 is etched using the remaining silicon photoresist 20 and the underlying silicon BARC 12 as a mask.

[0063] As shown in Figures 5(a)-5(c), another example of the method described herein involves forming a thick hydrocarbon BARC 11 (e.g., 10 nm to 2000 nm) on a substrate including silicon oxide 14 on metal 15. As shown in Figure 5(a), a silicon photoresist composition is applied, imagewise exposed to activating wavelength radiation, cured, and developed to remove the photoresist composition in the exposed areas, leaving silicon photoresist 20 that exhibits a pattern in the hydrocarbon BARC 11. As shown in Figure 5(b), the hydrocarbon BARC 11 is etched using the silicon photoresist 20 as a mask, exposing the silicon oxide 14. As shown in Figure 5(c), the silicon oxide 14 is etched using the remaining silicon photoresist 20 and the underlying hydrocarbon BARC 11 as a mask.

[0064] As shown in Figures 6(a)-6(c), another example of the method described herein involves applying a silicon photoresist layer 20 to a silicon substrate 21. After imagewise exposure, curing, and development, the pattern of the silicon photoresist 20 remains on the silicon substrate 21 as a mask, as shown in Figure 6(b). The silicon substrate 21 is then etched using the silicon photoresist 20 as a mask. As shown in Figure 6(c), residues of the silicon photoresist 20 can be left behind, or can be completely removed during etching (not shown). The remaining silicon photoresist can then serve as a mask for subsequent ion implantation into the exposed portions of the silicon substrate.

[0065] As shown in Figures 7(a)-7(c), another example of the method described herein involves forming a thin photosensitive hydrocarbon BARC 10 (e.g., 2 nm-200 nm) on a substrate including a polysilicon layer 13 on a silicon oxide layer 14. The photosensitive BARC is positive-acting because it has an increased dissolution rate in a developer when exposed to radiation at an activating wavelength.

[0066] Such photosensitive hydrocarbon BARC compositions can include an aromatic polymer resin and a photoactivator. For example, the aromatic polymer resin can include a novolac resin (a polymer derived from phenol and formaldehyde), a polyamic acid, a polyamic acid ester resin, or a combination thereof. For example, the hydrocarbon BARC composition can include a novolac resin and diazonaphthoquinone (DNQ). DNQ inhibits the dissolution of the novolac resin and increases its dissolution rate upon exposure, potentially exceeding the dissolution rate of the base novolac resin. The hydrocarbon BARC composition can include a novolac resin, DNQ, a polyamic acid, or a polyamic acid ester. The polyamic acid or polyamic acid ester can be present in an amount of 2 wt% to 20 wt% or 5 wt% to 10 wt%, based on the total weight of the hydrocarbon BARC composition. Photosensitive hydrocarbon BARCs containing a novolac resin and DNQ can be developed with a basic or alkaline developer. Examples of alkaline (basic) developers include aqueous solutions of organic or inorganic bases such as tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, ethanolamine, propylamine, ethylenediamine, choline, potassium hydroxide, sodium hydroxide, or combinations thereof. Specific examples of developers may include 0.1 to 0.4 normal (N) tetraalkylammonium hydroxides (e.g., C1 to C4 tetraalkylammonium hydroxides such as tetramethylammonium hydroxide).

[0067] The polyamic acid or polyamic acid ester can protect the hydrocarbon BARC from the mixed solvents used in silicon photoresists. The polyamic acid or polyamic acid ester can also be the reaction product of a dianhydride, particularly an aromatic dianhydride, with a diamine, particularly an aromatic diamine.

[0068] Examples of aromatic dianhydrides include pyromellitic dianhydride, biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, benzophenonetetracarboxylic dianhydride, diphenylethertetracarboxylic dianhydride, (p-phenylenedioxy)diphthalic anhydride, (isopropylidenediphenoxy)bis(phthalic anhydride), (hexafluoroisopropylidene)diphthalic anhydride, or a combination of two or more thereof. Alternatively, a combination comprising at least one of the above may be used. Examples of diamines include phenylenediamine, oxydianiline, or a combination thereof.

[0069] FIG. 7(a) shows a film stack including a silicon photoresist 20 on a photosensitive hydrocarbon BARC 10 on a polysilicon layer 13 on a silicon dioxide layer 14. As shown in FIG. 7(b), the silicon photoresist composition and the photosensitive hydrocarbon BARC are imagewise exposed to activating wavelength radiation, cured, and developed to remove the photoresist composition and the photosensitive hydrocarbon BARC in the exposed areas, leaving the silicon photoresist 20 patterned in the photosensitive hydrocarbon BARC 10. Exposure involves exposing areas of the silicon photoresist 20 to radiation, which simultaneously exposes the underlying photosensitive hydrocarbon BARC 10 to radiation. Development can be performed sequentially, developing the silicon photoresist first and then the underlying photosensitive BARC. Alternatively, both layers can be developed simultaneously using a mixed alkaline developer solution as described herein. As shown in FIG. 7(c), the polysilicon layer 13 is etched using the silicon photoresist 20 and the underlying photosensitive hydrocarbon BARC 10 as a mask.

[0070] This specification further discloses products made by the methods described herein. For example, the products may be electronic devices such as chips or integrated circuits, displays, or systems containing such devices. Examples of such systems include computers, mobile phones, transportation vehicles, appliances, manufacturing systems, robotic devices, etc.

[0071] Example Example 1: Synthesis of silicon-containing polymer resin for use in silicon photoresist A 500 mL round-bottom flask was charged with 65 g of methyltrimethoxysilane, 30 g of tetraethoxysilane, 10 g of phenyltrimethoxysilane, 250 g of 1-methoxy-2-propanol acetate, 48 g of water, and 10 g of acetic acid, mixed thoroughly, and distilled for 5 hours. The flask was removed from the heated still and transferred to a rotary evaporator, where all solvent was removed under a vacuum of 20 Torr at 80°C for 40 minutes. The silicon-containing resin was then recovered from the flask.

[0072] Example 2: Preparation of a thin silicon photoresist coating composition 5 g of the silicon-containing polymer resin obtained in Example 1 was placed in a container with 90 g of n-butanol, 10 g of propylene carbonate, 0.004 g of benzyltrimethylammonium chloride, and 0.12 g of a triarylsulfonium hexafluoroantimonate mixture (TR-PAG-201, Tronly New Electrical Materials Co., Ltd., Changzhou, China) and mixed until all components were dissolved. This solution was a thin liquid silicon photoresist.

[0073] Example 3: Preparation of a thick silicon photoresist coating composition 20 g of the silicon-containing polymer resin obtained in Example 1 was placed in a container with 30 g of n-butanol, 10 g of propylene carbonate, 0.008 g of benzyltrimethylammonium chloride, and 0.24 g of a triarylsulfonium hexafluoroantimonate mixture (TR-PAG-201, Changzhou Power Electronics New Materials Co., Ltd., China) and mixed until all components were dissolved. This solution was a liquid, thick silicon photoresist.

[0074] Example 4: Preparation of Thin Hydrocarbon BARC Composition 2 g of polystyrene resin with a weight average molecular weight of 50,000 Daltons was dissolved in 200 g of 1-methoxy-2-propanol acetate, resulting in a thin liquid hydrocarbon BARC.

[0075] Example 5: Preparation of Thick Hydrocarbon BARC Composition 180 g of acrylonitrile-styrene copolymer resin with a weight average molecular weight of 50,000 Daltons was dissolved in 720 g of 1-methoxy-2-propanol acetate. This solution was a liquid acrylonitrile-styrene thick hydrocarbon BARC.

[0076] Example 6: Preparation of another thick hydrocarbon BARC composition 40 g of novolac resin with a weight average molecular weight of 9000 daltons, 4 g of hexakis(methoxymethyl)melamine, and 0.4 g of p-toluenesulfonic acid were dissolved in 92 g of 1-methoxy-2-propanol acetate and 40 g of 1-methoxy-2-propanol. This solution was a liquid novolac resin thick hydrocarbon BARC.

[0077] Example 7: Preparation of Thin Silicone BARC Composition A 500 mL round-bottom flask was charged with 52 g of methyltrimethoxysilane, 8 g of phenyltrimethoxysilane, 24 g of β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 240 g of 1-methoxy-2-propanol acetate, 40 g of water, and 8 g of acetic acid, mixed thoroughly, and allowed to distill for 5 hours. A silicon-containing polymer resin was formed in the flask. 10 g of this silicon-containing polymer resin was then combined with 0.08 g of p-toluenesulfonic acid and 590 g of n-butanol and mixed until all components were dissolved. This solution was a thin liquid silicone BARC.

[0078] Example 8: Thick Silicon Photoresist and Thin Hydrocarbon BARC Process The thin hydrocarbon BARC composition obtained in Example 4 was spin-coated onto a silicon wafer at a rotation speed of 2000 rpm and baked at 120°C for 60 seconds to obtain a film with a thickness of 17 nm. The thick silicon photoresist composition obtained in Example 3 was spin-coated onto the thin hydrocarbon BARC film at a rotation speed of 1000 rpm to form a film with a thickness of approximately 800 nm. The wafer with such a coating was imagewise exposed to radiation having a wavelength of 365 nm to generate acid in the exposed areas. The wafer was then baked on a hot surface at 120°C for 60 seconds. Following this bake, the wafer was immersed in a 2.38 wt% aqueous solution of tetramethylammonium hydroxide for 20 seconds to form the desired pattern in the silicon photoresist film.

[0079] Example 9: Thick Silicon Photoresist and Thin Silicon BARC Process The thin silicon BARC composition obtained in Example 7 was spin-coated onto a silicon wafer at a rotation speed of 2000 rpm and baked at 150°C for 60 seconds to obtain a film with a thickness of approximately 20 nm. The thick silicon photoresist composition obtained in Example 3 was then spin-coated onto the thin hydrocarbon BARC film at a rotation speed of 1000 rpm to form a film with a thickness of 800 nm. The wafer bearing such a coating was imagewise exposed to radiation having a wavelength of 365 nm, generating acid in the exposed areas. The wafer was then baked on a hot surface at 120°C for 60 seconds. Following this bake, the wafer was immersed in a 2.38 wt% aqueous solution of tetramethylammonium hydroxide for 20 seconds to form the desired pattern in the silicon photoresist film.

[0080] Example 10: Thin Silicon Photoresist and Thick Hydrocarbon BARC Process The thick hydrocarbon BARC composition obtained in Example 5 was spin-coated onto a silicon wafer at a rotation speed of 3000 rpm and baked at 150°C for 60 seconds, resulting in a film with a thickness of approximately 2000 nm. The thin silicon photoresist obtained in Example 2 was then spin-coated onto the thick hydrocarbon BARC film at a rotation speed of 2000 rpm to form a film with a thickness of approximately 100 nm. The wafer bearing such a coating was imagewise exposed to radiation having a wavelength of 365 nm, generating acid in the exposed areas. The wafer was then baked on a hot surface at 120°C for 60 seconds. Following this bake, the wafer was immersed in a 2.38 wt% aqueous solution of tetramethylammonium hydroxide for 20 seconds, resulting in the desired pattern being formed in the silicon photoresist film.

[0081] Example 11: Thin Silicon Photoresist and Alternative Thick Hydrocarbon BARC Process The thick hydrocarbon BARC film obtained in Example 6 was spin-coated onto a silicon wafer at a rotation speed of 3000 rpm and baked at 150°C for 60 seconds to obtain a film with a thickness of approximately 2000 nm. The thin silicon photoresist obtained in Example 2 was spin-coated onto the thick hydrocarbon BARC film at a rotation speed of 2000 rpm to obtain a film with a thickness of approximately 100 nm. The wafer with such a coating was imagewise exposed to radiation having a wavelength of 365 nm to generate acid in the exposed areas. The wafer was then baked on a hot surface at 120°C for 60 seconds. Following this bake, the wafer was immersed in a 2.38 wt% aqueous solution of tetramethylammonium hydroxide for 20 seconds to form the desired pattern in the silicon photoresist film.

[0082] Example 12: Processing of thick silicon photoresist on HMDS-treated silicon surfaces The thick silicon photoresist obtained in Example 3 was spin-coated onto a silicon wafer surface pretreated with HMDS at a rotation speed of 1000 rpm to form a film of approximately 800 nm. The wafer with such a coating was imagewise exposed to radiation having a wavelength of 365 nm, generating acid in the exposed areas. The wafer was then baked on a hot surface at 120°C for 60 seconds. Following this bake, the wafer was immersed in a 2.38 wt% aqueous solution of tetramethylammonium hydroxide for 20 seconds to form the desired pattern on the silicon photoresist film.

[0083] Example 13: Processing of thick silicon photoresist on bare silicon surfaces The thick silicon photoresist obtained in Example 3 was spin-coated onto a pre-cleaned and dried silicon wafer surface at a rotation speed of 1000 rpm to form a film of approximately 800 nm. The wafer with such a coating was imagewise exposed to radiation having a wavelength of 365 nm, generating acid in the exposed areas. The wafer was then baked on a hot surface at 120°C for 60 seconds. Following this bake, the wafer was immersed in a 2.38 wt% aqueous solution of tetramethylammonium hydroxide for 20 seconds to form the desired pattern in the silicon photoresist film.

[0084] The present disclosure further includes the following aspects.

[0085] Aspect 1 A method of forming a pattern includes providing a substrate on which a pattern is to be formed, forming a silicon photoresist layer on the substrate, exposing portions of the silicon photoresist to radiation at an activating wavelength, hardening the silicon photoresist, developing the hardened silicon photoresist to remove portions of the photoresist exposed to radiation at the activating wavelength, and etching the substrate to form the pattern.

[0086] Aspect 2 In the method described in Aspect 1 above, the silicon photoresist, before curing, comprises: a silicon-containing resin; a catalyst that can catalyze a condensation reaction of the silicon-containing resin but that is deactivated in the presence of an acid and loses the ability to catalyze the condensation reaction; and a photoacid generator.

[0087] Aspect 3 In the method according to aspect 1 or 2 above, the silicon photoresist comprises at least 35 wt%, preferably at least 40 wt%, and more preferably more than 41 wt% silicon, based on the total weight of the silicon photoresist.

[0088] Aspect 4 In the above-described method, the substrate comprises a microelectronic wafer of silicon, polycrystalline silicon, silicon dioxide or aluminum-aluminum oxide, gallium arsenide, silicon carbide, ceramics, quartz, metal, or a combination of two or more thereof.

[0089] Aspect 5 The method described above further includes the steps of: forming a bottom anti-reflective coating containing a polymer on the substrate; forming the silicon photoresist layer on the bottom anti-reflective coating; developing the hardened silicon photoresist to expose a portion of the bottom anti-reflective coating; and etching the exposed portion of the bottom anti-reflective coating to expose a portion of the substrate before etching the substrate.

[0090] Aspect 6 In the method described in Aspect 5 above, the lower antireflective coating is characterized in that the polymer is not crosslinked and the lower antireflective coating contains a chromophore that is not grafted to the polymer.

[0091] Aspect 7 In the method according to the above-mentioned aspect 5 or 6, the bottom antireflective coating comprises a hydrocarbon-containing polymer.

[0092] Aspect 8 In the method according to the above-mentioned aspect 5 or 6, the lower antireflective coating comprises a silicon-containing polymer.

[0093] Aspect 9 In the method according to the above aspect 8, the lower antireflective coating is derived from an alkylsiloxane, an alkylsilsesquioxane, an arylsiloxane, an arylsilsesquioxane, an alkenylsiloxane, an alkenylsilsesquioxane, or a combination of two or more thereof.

[0094] Aspect 10 In the method according to any one of the above aspects 5 to 7, the lower antireflective film is not crosslinked.

[0095] Aspect 11 In the method according to the above aspect 5, 8 or 9, the lower antireflective coating is crosslinked.

[0096] Aspect 12 In the method described above, the silicon photoresist layer has a thickness of 2 nm to 1000 nm.

[0097] Aspect 13 In the method according to any one of the above aspects 5 to 11, the silicon photoresist layer has a thickness of 2 nm to 1000 nm, and the lower anti-reflective coating has a thickness of 2 nm to 200 nm.

[0098] Aspect 14 In the method according to any one of Aspects 5 to 11, the silicon photoresist layer has a thickness of 2 nm to 200 nm, preferably 3 nm to 90 nm, and more preferably 5 nm to 60 nm, and the lower antireflective coating has a thickness of 10 nm to 2000 nm, and preferably 85 nm to 1000 nm.

[0099] Aspect 15 In the above-described method, the substrate comprises a layer to be patterned, the layer comprising polycrystalline silicon or silicon oxide.

[0100] Aspect 16 In the method described in Aspect 1 above, the layer on the substrate consists essentially of silicon or silicon treated with an adhesion promoter.

[0101] Aspect 17 In the method of aspect 16, the adhesion promoter is a silylating agent.

[0102] Aspect 18 The method according to any one of Aspects 1 to 4, further comprising the steps of: forming a bottom antireflective coating containing a positive photosensitive hydrocarbon-containing composition on the substrate; forming a silicon photoresist layer on the bottom antireflective coating; exposing the silicon photoresist to radiation at an activating wavelength and exposing a portion of the bottom antireflective coating to the radiation at the activating wavelength; and developing the exposed bottom antireflective coating to remove the exposed portion of the photosensitive bottom antireflective coating and expose a portion of the substrate.

[0103] Aspect 19 In the method according to the above-described aspect 18, the photosensitive hydrocarbon-containing composition includes a novolac resin and a diazonaphthoquinone.

[0104] Aspect 20 In the method according to the above aspect 18 or 19, the development of the underlying antireflective coating and the development of the silicon photoresist are carried out simultaneously in a basic solution.

[0105] Aspect 21 The product was produced by the method described in any one of Aspects 1 to 20. All ranges disclosed herein include their endpoints, and each endpoint is independently combinable with the others. For example, the range "25 wt% or less, particularly 5 wt% to 20 wt%" includes both the "5 wt% to 25 wt%" endpoint and all values within that range. Ranges can also be formed by combining the upper and lower limits. For example, the expressions "at least 1 wt% or at least 2 wt%" and "10 wt% or less or 5 wt% or less" can be combined to form the ranges "1 wt% to 10 wt%, "1 wt% to 5 wt%, "2 wt% to 10 wt%, and "2 wt% to 5 wt%."

[0106] The terms used herein are for the purpose of describing particular embodiments only and are not intended to be limiting. As used herein, the terms "a," "one," "the," and "at least one" do not limit quantity and are intended to include both the singular and the plural, unless otherwise defined in the surrounding text. For example, "an element" and "at least one element" have the same meaning, unless otherwise defined in the surrounding text. "At least one" should not be interpreted as limiting "one" or "one." "Or" means "and / or." As used herein, the term "and / or" includes one or more of the associated listed items, in whole or in any combination. Furthermore, terms such as "comprise" or "comprising," when used herein, refer to the presence of stated features, regions, integers, steps, operations, elements, and / or components, but do not imply the exclusion of the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and / or groups thereof.

[0107] Unless otherwise specified, all terms (including technical and scientific terms) used in this specification have the meanings commonly understood by those skilled in the art to which this disclosure belongs. Terms defined in general dictionaries should be understood to have the same meanings as those in the relevant field and in the context of this disclosure. Terms should not be construed as having ideal or overly formal meanings unless specifically defined in this specification.

[0108] The present disclosure may alternately comprise, consist of, or consist essentially of any suitable elements disclosed herein. The present disclosure may additionally or alternatively be formulated to be free of, or substantially free of, any elements, materials, ingredients, adjuvants, or substances used in prior art compositions or that are not necessary to achieve the function and / or purpose of the present disclosure.

[0109] All cited patents, patent applications, and other documents are incorporated herein by reference in their entirety. However, if a term in this specification contradicts or conflicts with a term in a cited document, the term in this specification will take precedence over the term in the cited document.

[0110] Unless otherwise limited herein, all test standards are the latest standards in effect as of the filing date of this application, or, if priority is claimed, the test standards are the latest standards in effect as of the filing date of the earliest listed priority application.

Claims

1. providing a substrate on which a pattern is to be formed; forming a silicon photoresist layer on the substrate; exposing a portion of the silicon photoresist to radiation at an activating wavelength; curing the silicon photoresist; developing the hardened silicon photoresist to remove portions of the photoresist exposed to radiation at the activating wavelength; and etching the substrate to form the pattern. A method for forming a pattern comprising:

2. Before curing, the silicon photoresist contains a silicon-containing resin, a catalyst that can catalyze a condensation reaction of the silicon-containing resin but is deactivated in the presence of an acid to lose the ability to catalyze the condensation reaction, and a photoacid generator. The method of claim 1.

3. The silicon photoresist comprises at least 35 wt %, preferably at least 40 wt %, and more preferably greater than 41 wt % silicon based on the total weight of the silicon photoresist.

3. The method according to claim 1 or 2.

4. The substrate comprises a microelectronic wafer of silicon, polycrystalline silicon, silicon dioxide or aluminum-aluminum oxide, gallium arsenide, silicon carbide, ceramics, quartz, metal, or a combination of two or more thereof.

4. The method according to claim 1.

5. forming a bottom anti-reflective coating on the substrate, the bottom anti-reflective coating comprising a polymer; forming a silicon photoresist layer on the bottom anti-reflective coating, and developing the hardened silicon photoresist to expose a portion of the bottom anti-reflective coating; and before etching the substrate, etching the exposed portion of the lower anti-reflective coating to expose a portion of the substrate.

5. The method according to any one of claims 1 to 4.

6. The lower anti-reflection film is the polymer is not crosslinked; The polymer contains a non-grafted chromophore. characterized by one or two of the following: The method of claim 5.

7. The lower anti-reflective coating comprises a hydrocarbon-containing polymer.

7. The method according to claim 5 or 6.

8. The lower anti-reflective coating comprises a silicon-containing polymer.

7. The method according to claim 5 or 6.

9. The lower anti-reflective coating is derived from an alkylsiloxane, an alkylsilsesquioxane, an arylsiloxane, an arylsilsesquioxane, an alkenylsiloxane, an alkenylsilsesquioxane, or a combination of two or more thereof. The method of claim 8.

10. The lower anti-reflective coating is not crosslinked.

8. The method according to any one of claims 5 to 7.

11. The lower anti-reflective coating is crosslinked The method according to any one of claims 5, 8 and 9.

12. The silicon photoresist layer has a thickness of 2 nm to 1000 nm.

12. The method according to any one of claims 1 to 11.

13. The silicon photoresist layer has a thickness of 2 nm to 1000 nm, and the lower anti-reflective coating has a thickness of 2 nm to 200 nm.

12. The method according to any one of claims 5 to 11.

14. The silicon photoresist layer has a thickness of 2 nm to 200 nm, preferably 3 nm to 90 nm, more preferably 5 nm to 60 nm, and the lower anti-reflective coating has a thickness of 10 nm to 2000 nm, preferably 85 nm to 1000 nm.

12. The method according to any one of claims 5 to 11.

15. The substrate includes a layer on which a pattern is to be formed, the layer including polycrystalline silicon or silicon oxide.

15. The method of any one of claims 1 to 14.

16. The layer on the substrate consists essentially of silicon or silicon treated with an adhesion promoter. The method of claim 1.

17. The adhesion promoter is a silylating agent 17. The method of claim 16.

18. forming a bottom antireflective coating on the substrate, the bottom antireflective coating comprising a positive photosensitive hydrocarbon-containing composition; and forming the silicon photoresist layer on the bottom antireflective coating; exposing the silicon photoresist to radiation at the activating wavelength and exposing a portion of the underlying antireflective coating to radiation at the activating wavelength; and developing the exposed lower anti-reflective coating to remove the exposed portion of the lower anti-reflective coating and expose a portion of the substrate.

5. The method according to any one of claims 1 to 4.

19. The photosensitive hydrocarbon-containing composition contains a novolac resin and a diazonaphthoquinone.

20. The method of claim 18.

20. The development of the lower anti-reflective coating and the development of the silicon photoresist are carried out simultaneously in a basic solution.

20. The method of claim 18 or 19.

21. Produced by the method of any one of claims 1 to 20 A product characterized by:

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