Tin dodecamer and radiation-patternable coating having strong EUV absorption

Abstract

SOLUTION: There are described patterning compositions based on organo tin dodecamers with hydrocarbyl ligands, oxo ligands, hydroxo ligands and carboxylato ligands. Alternative dodecamer embodiments have organo tin ligands in place of hydrocarbyl ligands. The organo tin ligands can be incorporated into the dodecamers from a monomer with the structure (RCC)3SnQ, where R is a hydrocarbyl group and Q is an alkyl tin moiety with a carbon bonded to the Sn atom of the monomer and with a Sn bonded as a replacement of a quaternary carbon atom with bonds to 4 carbon atoms. Some or all of the carboxylato and hydroxyl ligands can be replaced with fluoride ions.EFFECT: Good EUV patterning results are obtained with the dodecamer based patterning compositions.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] Cross-reference of related applications This application claims priority to Cardineau et al.'s concurrently pending U.S. Provisional Patent Application No. 62 / 653,043, filed on April 5, 2018, entitled “Photoresists With High EUV Absorption” (as incorporated herein by reference).

[0002] The present invention relates to alkyltin clusters suitable for forming radiation-patternable coatings. The present invention further relates to alkyl ligands having tin atoms incorporated in the ligand. [Background technology]

[0003] Extreme ultraviolet (EUV) lithography is a method for manufacturing high-performance integrated circuits containing high-density structures patterned on the nanoscale. To manufacture these circuits, a photoresist is deposited on a substrate and exposed to a pattern of EUV light. The exposed areas undergo radiolysis, changing their solubility, which allows for the precise transfer of the EUV light pattern to the resist after solvent development and further processing. The developed photoresist pattern is then transferred to the underlying substrate by an etching process. [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] The fabrication of semiconductor circuits and devices has been accompanied by a continuous reduction in critical dimensions across generations. These dimensional reductions necessitate novel materials and methods to meet the demands of processing and patterning increasingly smaller features. Patterning generally involves selectively exposing thin layers of radiosensitive material (resist) to form a pattern, which is then transferred to subsequent layers or functional materials. A new and promising class of metal-based radioresists has been discovered that exhibits good absorption of extreme ultraviolet (EUV) and electron beam radiation, while simultaneously achieving very high etching contrast. EUV has proven to be a crucial tool in semiconductor fabrication for obtaining smaller patterned features, and resist compositions that leverage the advantages of EUV can be valuable components in this endeavor. [Means for solving the problem]

[0005] In the first aspect, the present invention relates to formula (QSn) 12 O 14 (OH)6(RCO2)2 (wherein R is H or an alkyl group having 1 to 10 carbon atoms, Q is a hydrocarbyl group having 3 to 31 total carbon atoms, or Q is structurally -(CH2) n The present invention relates to a composition comprising a tin dodecamer represented as Sn(R1R2R3), where n=1 to 4, and is an alkyltin group having 4 to 15 total carbon atoms, where R1, R2, and R3 are independently alkyl groups having 1 to 5 carbon atoms. In some embodiments, the solvent for forming a radiation-patternable coating may be an organic solvent, and the composition comprises a tin dodecamer.

[0006] In a further embodiment, the present invention relates to the formula (RCC)3SnQ (wherein R is a hydrocarbyl group having 1 to 15 carbon atoms, and Q is a structure-(CH2) nIt relates to a composition containing a tin compound represented by Sn(R1R2R3), which is an alkyltin group having 4 to 15 carbon atoms in total, n = 1 to 4, and R1, R2, and R3 are independently alkyl groups having 1 to 5 carbon atoms).

[0007] In a further aspect, the present invention is a method for forming an organotin compound comprising: A step of gradually adding tin dihalide to a solution containing an organic solvent, alkylacetylene, and alkylmagnesium halide to form a tin intermediate solution; A step of mixing XCH2Sn(R1R2R3) (where X is a halide and R1, R2, and R3 are independently alkyl groups having 1 to 5 carbon atoms) with the above tin intermediate solution to form (RCC)3SnCH2Sn(R1R2R3) of a solid compound, It relates to a method comprising.

[0008] In another aspect, the present invention is (QSn) n O 3n / 2-1 / 2x-1 / 2y F x (OH) y , 1 ≦ n ≦ 12, (0 < x + y ≦ 8), and (Q is an alkyl group having 1 to 16 carbon atoms, or an alkyltin group having a structure —CH2Sn(R1R2R3) having 4 to 15 carbon atoms in total, and R1, R2, and R3 are independently alkyl groups having 1 to 5 carbon atoms). In some embodiments, the solution for forming a radiation-patternable coating can comprise an organic solvent and this composition containing a fluorinated tin dodecamer.

[0009] In another aspect, the present invention is of the formula (QSn) 12 O 14 (OH)6(HCO2)2 (where Q is an alkyl group having 5 to 16 carbon atoms in total, or Q has a structure —(CH2) nA method for fluorinating a dodecamer tin composition represented by (Sn(R1R2R3), n=1-4, and an alkyltin group having 4-15 total carbon atoms, where R1, R2, and R3 are independently alkyl groups having 1-10 carbon atoms), comprising the step of reacting alkyltin hydroxide with a trialkylamine hydrofluoric acid salt. [Brief explanation of the drawing]

[0010]

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[0011] Alkyl tin clusters offer promising properties for radiation-based patterning, and the tin dodecamers described herein can be appropriately processed for EUV patterning of tin. One synthetic method for synthesizing dodecamers from alkyl tin triacetide monomers is described herein. Also described herein are alkyl groups having tin ligands that can be used to effectively convert triacetide monomers into dodecamer embodiments that also have additional tin atoms in the ligands. The tin dodecamers have oxo ligands, hydroxo ligands, and formate ligands, some of which crosslink to stabilize the cluster. A method for substituting formate ligands and / or hydroxide ligands with fluoride ions is disclosed. The tin dodecamer clusters are solid compounds that are soluble in suitable organic liquids. Patterning formulations based on stabilized tin dodecamers are described. Based on these tin clusters with a higher tin content, coatings formed from tin compositions exhibit high EUV absorption.

[0012] EUV sources generally produce lower luminosity than other DUV and UV laser systems and lamps used in lithography. This lower luminosity can lead to the formation of undesirable defects in the resist pattern due to EUV shot noise and the irregular nature of chemical reactions in the photoresist. These stochastic events are less likely to occur in photoresists that strongly absorb EUV radiation and undergo chemical changes that efficiently result in higher solubility contrast between exposed and unexposed areas.

[0013] A thin photoresist provides the highest fidelity pattern for transfer to the underlying substrate. Therefore, an effective EUV photoresist should have a very large EUV absorption cross-section to improve both defect resistance and writing speed. Meyers et al., in U.S. Patent No. 9,310,684, entitled “Organometallic Solution Based High Resolution Patterning Compositions” (incorporated herein by reference), describe novel organotin photoresist compositions with high absorption coefficients for EUV lithography. The solution coating and film compositions comprise tin bonded by alkyl groups and further crosslinked by oxo(O) and / or hydroxo(-OH) groups. Here, the inventors describe novel compositions exemplified by substituting the C, O, and -OH groups with stronger EUV-absorbing species. The carbon atoms C in the alkyl chain can be substituted with Sn, and the O and -OH groups can be substituted with F. The comparison of cross-sectional areas in Table 1, based on reported atomic absorption data (http: / / henke.lbl.gov / optical_constants / pert_form.html), shows that these substitutions can yield greater EUV absorption. In Table 1, absorption is expressed in cm³ of EUV light at 13.5 nm. 2 Reported in atomic units.

[0014] [Table 1]

[0015] Substitution of the OH group with fluorine also limits condensation that can occur when a hydroxytin species binds and H2O is removed. By suppressing condensation in this way, the stability of the photoresist solution and the reproducibility of patterning performance can be improved.

[0016] Tin clusters have been synthesized that ensure high EUV absorption while simultaneously maintaining good coating properties and solution processing capabilities. Tin trimers and other clusters have been previously described in Cardineau et al.'s concurrently pending U.S. Patent Application No. 16 / 194,491 (hereinafter referred to as '491') entitled “Organotin Clusters, Solutions of Organotin Clusters, and Application to High Resolution Patterning” (incorporated herein by reference). '491' teaches the use of alkyltin trialkylacetylide monomers, particularly alkyltin triphenylacetylide monomers, for forming clusters. In some embodiments, these monomers are used to form the dodecomers described herein. Tin dodecomers having structures useful for resist processing, such as the two exemplified tin dodecomers, are described as providing high EUV absorption.

[0017] Dodecamer (QSn) 12 O 14 (OH)6(RCO2)2 (Q = alkyl or alkyltin ligand and R = alkyl group or H) is a typical organotin cluster formulated as a metal oxide EUV photoresist. Furthermore, carboxylates, e.g., formates, and sometimes some or all hydroxide ligands can be substituted with fluoride ions, as described later. The Q ligand can generally have a quaternary carbon atom or a tin atom. In the case of alkyl groups with a quaternary carbon atom, these alkyl groups are generally known to form the desired patterned coating, and these ligands can generally have 5 to 17 carbon atoms. Alkyltin ligands have a tin atom instead of the quaternary carbon of a similar alkyl group and can contain 4 to 16 carbon atoms. Ligands in which the quaternary carbon is substituted with Sn still yield the dodecamer C-Sn bond in the above formula, resulting in Sn-(CH2) nA -Sn moiety is formed, where n in the formula is 1 to 4. Substitution of quaternary carbon can be advantageous for EUV lithography because Sn has a wider EUV absorption cross-section than C (see Table 1).

[0018] Suzu Cluster (BuSn) 12 O 14 (OH)6 +2 and (i-PrSn) 12 O 14 (OH)6 +2 The synthesis of these materials is described by Eychenne-Baron et al. (hereafter Eychenne-Baron), “New synthesis of the nanobuilding block {(BuSn) 12 O 14 (OH)6} 2+ and exchange properties of {(BuSn) 12 O 14 (OH)6}(O3SC6H4CH3)2,”J.Organometallic Chemistry 1998,567,137-142, and Puff et al. Kaefig-ion[(i-PrSn) 12 O 14 (OH)6 +2 This is described in J. Organometallic Chemistry 1989, 373, 173-184, both of which are incorporated herein by reference. A very specific synthetic method for forming the aforementioned compositions having sterically bulky neopentyl-based alkyl ligands (occasionally substituted with quaternary tin atoms) that have been shown to adequately stabilize the clusters, and for introducing the formate anion, is described herein.

[0019] Puff described the isolation of compounds having a chloride anion and associating with solvent molecules (water, or DMF (dimethylformamide) or DMPU (water with N,N'-dimethylpropylene urea)). Eychenne-Baron studied the substitution of as-synthesized compounds having a p-toluenesulfonyl anion and succeeded in partial substitution of the group with an acetate group. The synthetic method of the present invention allows for the preparation of dodecamers as formate salts having other alkyl substituents.

[0020] It was found that good patterning performance can be obtained with branched alkyl ligands of medium size. Quaternary C * The simplest alkyl group containing atoms is neopentyl(CH3)3C * It has a CH2- structure, which can be called a t-amyl group. This neopentyl portion is (R1R2R3)C * (CH2) n -This can be generalized as follows, where n is an integer from 1 to 4 (i.e., 1, 2, 3, or 4), but in general C * It is simply written as C, * The term "quaternary carbon" is simply used to introduce the concept of quaternary carbon. Generalized groups maintain the same ligand bond, sometimes with an extended alkyl structure. Generally, the R1, R2, and R3 portions may independently be groups having 1 to 5 carbon atoms, such as methyl (CH3-) and ethyl (CH3CH2-). Quaternary C * Substitute with Sn to obtain the corresponding alkyltin ligand (CH3)3SnCH2- or generally (R1R2R3)Sn(CH2) n - can be formed, where n is an integer from 1 to 4, and R1, R2, and R3 are as described above. Other branched alkyl groups such as tert-butyl((CH3)3C-), sec-butyl(CH3CHCH2CH3), isobutyl(CH3)2CHCH2-, and isopropyl((CH3)2CH-) may be preferred, and in some embodiments, unbranched alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, and larger groups may be preferred.

[0021] In this specification, ligands having a quaternary carbon or tin center have been found to be useful for bonding to the Sn atom to form monomers for the eventual synthesis of dodecamers. These monomers generally have the structure QSn(C6H5CC)3, where Q in phenylacetylide is a cluster alkyl or alkyltin ligand. The monomer (CH3)3SnCH2Sn(C6H5CC)3 is exemplified below, and is considered to be the first example of a monoalkyloxohydroxotin species in which the C in the alkyl group is substituted with Sn. This monomer can be further modified using another alkyl ligand substituent -(CH2) n (C6H5CC)3Sn(CH2) has 5 to 16 total carbon atoms in the C(R1R2R3) ligand. n As C(R1R2R3), or -(CH2) n (C6H5CC)3Sn(CH2) has 4 to 15 total carbon atoms in the Sn(R1R2R3) ligand. n The trialkylacetylide monomer can be generalized as Sn(R1R2R3), where n=1, 2, 3, or 4, and R1, R2, and R3 are independently linear or branched alkyl groups having 1 to 5 carbon atoms. The trialkylacetylide monomer can also be generalized as (R'CC)3SnQ with another substituent, where R' is an organic group having 1 to 15 carbon atoms, such as an alkyl group, an alkenyl group, an aromatic group, the corresponding halogenated type, or a derivative thereof.

[0022] The aforementioned trialkylacetylide monomers can be hydrolyzed and condensed under appropriate conditions to form a dodecamer (QSn). 12 O 14(OH)6(HCO2)2 is formed, where Q may contain a tin atom. A solution of this dodecamer in an organic solvent can be readily deposited as a thin film by spin coating or other appropriate treatment. Based on the reported atomic EUV absorption cross-section, film thickness of 25 nm, and packing density equivalent to that of the neopentyltin dodecamer film, films with alkytin ligands are expected to absorb approximately 1.5 times the number of EUV photons compared to the corresponding neopentyl system. Analysis of the corresponding EUV exposure sequences shows that the desired performance is achieved, as described in the following examples. The dodecamer compound is solid and generally crystalline. ((CH3)3CSn) 12 O 14 The crystal structure of (OH)6(HCO2)2 is shown in the following example.

[0023] Each R (alkyl) group is individually bonded to a tin atom and generally has 1 to 31 carbon atoms, with 3 to 31 carbon atoms in one group being secondary bonds and 4 to 31 carbon atoms in one group being tertiary bonds. However, in some embodiments, each R group may have 20 or fewer carbon atoms, and in further embodiments, 15 or fewer carbon atoms. Those skilled in the art will understand that further ranges of carbon number within the explicitly stated range above will be considered and that they will fall within the scope of this disclosure. In particular, the R-Sn portion of the cluster is R 1 R 2 R 3 It can be represented by CSn, R 1 and R 2 R is an alkyl group having 1 to 10 carbon atoms independently. 3 In some patterning compositions where is hydrogen or an alkyl group having 1 to 10 carbon atoms, a branched alkyl ligand may be desirable. In some embodiments, R 1 and R 2 R can form a cyclic alkyl moiety, 3 It can also bond to another group in the cyclic portion. Suitable branched alkyl ligands include, for example, isopropyl(R 1 and R 2is methyl, R 3 (where is hydrogen), tert-butyl (R 1 , R 2 , and R 3 (is methyl), tert-amyl (R 1 and R 2 is methyl, R 3 (is -CH2CH3), sec-butyl (R 1 is methyl, R 2 is -CH2CH3, and R 3 (is hydrogen), neopentyl (R 1 and R 2 is hydrogen, R 3 The cyclic group may be -C(CH3)3, cyclohexyl, cyclopentyl, cyclobutyl, and cyclopropyl. Suitable examples of cyclic groups include, for example, 1-adamantyl (-C(CH2)3(CH)3(CH2)3 or tricyclo(3.3.1.13,7)decane, which bond to a metal at the tertiary carbon) and 2-adamantyl (-CH(CH)2(CH2)4(CH)2(CH2) or tricyclo(3.3.1.13,7)decane, which bond to a metal at the secondary carbon). In another embodiment, the hydrocarbyl group may be an aryl or alkenyl group, such as a benzyl or allyl group, or an alkynyl group. In another embodiment, the hydrocarbyl ligand R may be any group consisting only of C and H and containing 1 to 31 carbon atoms. For example, linear or branched alkyl groups (i-Pr((CH3)2CH-), t-Bu((CH3)3C-), Me(CH3-), n-Bu(CH3CH2CH2CH2-)), cycloalkyl groups (cyclopropyl, cyclobutyl, cyclopentyl), olefin groups (alkenyl, aryl, allyl), or alkynyl groups, or combinations thereof. In further embodiments, suitable R groups include hydrocarbyl groups substituted with heteroatom functional groups such as cyano, thio, silyl, ether, keto, ester, or halogenated groups, or combinations thereof.

[0024] The synthesis of triacetylide tin monomers is discussed in the aforementioned application '491' and the following examples. As mentioned above, the monomers are alkyl or alkyltin tin trialkyl acetylides. In particular, application '491' describes the synthesis of t-butyltin triphenyl acetylide based on the reaction of phenylacetylene with t-butyltin tris(dimethylamide). Generally, alkyltin acetylides are alkylacetylide anions (R'C≡C - It can be synthesized by the addition of ) to RSnCl3, the addition of an alkyl anion to Sn(C≡CR”)4, or the reaction of HC≡CR” with RSn(NR'''2)3. Acetylide anions can be formed using a very strong base to form a compound RC≡CM with a suitable cation, where M is lithium, sodium, potassium, or magnesium halide [MgX]. + Zinc halide [ZnX] + (X = halide), or another ion having an electronegativity.

[0025] Regarding the synthesis of alkyltin-tin trialkylacetylides in the examples herein, the reaction can be carried out using an alkylacetylene such as phenylacetylene, which is reacted with a superstrong base such as isopropylmagnesium chloride in an organic solvent to form an organometallic alkylacetylide. Suitable organic solvents include tetrahydrofuran and other polar nonreactive solvents, which are generally aprotic. After the reaction of the alkylacetylene with the superstrong base, tin dihalide dissolved in the organic solvent is added, and the solution is reacted at room temperature for at least 1 hour. Next, (haloalkyl)trialkylstannane is added to the reaction mixture, and the reaction is carried out for at least 5 minutes, which can be done at room temperature. Using the above notation, this haloalkyl group is the monomer -(CH2) nThe trialkyl group of stannan becomes the R1, R2, and R3 moieties of the monomer. The resulting alkyltin-tin-trialkylacetylide product forms a solid precipitate, which can be collected and washed away. The product can be further crystallized by recrystallization from a hydrocarbon solvent such as pentane or hexane.

[0026] The synthesis of the dodecamer begins by adding a small amount of water to an organic solution of the monomers. Suitable organic solvents include, but are not limited to, alcohols or tetrahydrofurans, although many organic solvents in general will be suitable. Water is added in approximately stoichiometric amounts so that one water molecule is obtained with respect to each alkylacetylide ligand. This initial reaction is carried out for at least 1 hour and can be carried out at room temperature for several days, and in the examples, the reaction is carried out for 3 days. This initial reaction is thought to involve the formation of the dodecamer in the form of hydroxides. After the completion of this initial reaction, a carboxylic acid is added to the product of the initial reaction. Before adding the carboxylic acid, the solution may or may not be heated to a boil. The following examples use formic acid. The carboxylic acid can generally be added gradually in approximately stoichiometric amounts. After adding the formic acid, the solution is stirred for a further time, generally at least 1 minute or more. The resulting solid product can be collected and washed. Recrystallization of the product may be desirable.

[0027] By reacting with trialkylamine hydrofluoride salts, such as triethylamine [(CH2CH2)3N·3HF], a dodecamer (t-BuSn) is formed. 12 O 14 (OH)6(HCO2)2, or more generally, the dodecamer (QSn) 12 O 14The formate ions and / or hydroxide ions or a portion thereof in (OH)6(HCO2)2 can be substituted with fluoride ions, where Q is an alkyl ligand or a tin alkyl ligand as described above. Ammonium dehydrofluoride (NH4HF2) or other HF sources can be used instead of trialkylamine hydrofluoric acid salts. In the following example, the dodecamer (t-BuSn) 12 O 14 The substitution of eight fluorides—six hydroxides and two formates—by reaction with triethylamine hydrofluoride to form F8 is described. This substitution is considered previously unknown in the chemical properties of the monoalkyl oxo-hydroxosin dodecamer. Complete substitution of hydroxides and formates by fluorides is confirmed by chemical and NMR analyses. Mass spectrometry shows that partial substitution may also occur. A solution of the fluoride dodecamer in a suitable organic solvent can be spin-coated as a thin film suitable for EUV lithography. Analysis of the exposure sequence reveals excellent performance, as described in the following examples.

[0028] The use of alkyl-substituted metal coordination compounds in high-performance radiation-based patterning compositions is described, for example, in U.S. Patent No. 9,310,684, entitled “Organometallic Solution Based High Resolution Patterning Compositions,” by Meyers et al. (incorporated herein by reference). Improvements to these organometallic compositions for patterning are described in U.S. Patent Application Publication No. 2016 / 0116839 A1, entitled “Organometallic Solution Based High Resolution Patterning Compositions and Corresponding Methods,” and U.S. Patent Application Publication No. 2017 / 0102612 A1, entitled “Organotin Oxide Hydroxide Patterning Compositions, Precursors, and Patterning,” both of which are incorporated herein by reference. The organometallic compositions in these references have a structure based on one metal part. The metal clusters described herein contain a bridging group between two or three metal atoms. Compositions based on metal clusters can be effectively used in patterning and may offer processing advantages.

[0029] To form a resist precursor solution, the cluster composition can be dissolved in a suitable organic solvent. It has been shown to be soluble in chloroform, ketones, alcohols, and a range of polar organic solvents. The alcohol may be one or more of 1-methoxy-2-propanol, 4-methyl-2-pentanol, cyclopentanol, methanol, ethanol, n-propanol, or isopropanol, or mixtures thereof. Suitable alcohols include, for example, alkoxy alcohols having 4 to 10 carbon atoms. Suitable solvents include, for example, propylene glycol methyl ether acetate. The alkyltin dodecamer composition is also soluble in solutions containing one or more polar ethers, such as tert-butyl methyl ether and anisole, ethyl lactate, and cyclic ethers, such as tetrahydrofuran. Other organic solvents based on the specific solvents mentioned above may also be suitable. The concentration of tin may be in the range of about 1 mM to about 1 M, in a further embodiment about 2 mM to about 750 mM, and in another embodiment about 5 mM to about 500 mM, based on the amount of tin. For most solvents, it may be desirable to add a carboxylic acid to the solution to stabilize the cluster composition with its carboxylate anion. Formic acid or other carboxylic acids can be added as stabilizers at concentrations of about 1% to 30% v / v, and in further embodiments, about 5% to 20% v / v, which is the volume added per unit volume of the mixture. Generally, the choice of organic solvent may be influenced by its solubility parameter, volatility, flammability, toxicity, viscosity, and potential chemical interactions with other processing materials. Those skilled in the art will understand that further concentration ranges within the explicitly stated range above will be considered and that they will fall within the scope of this disclosure. Generally, the precursor solution can be thoroughly mixed using a suitable mixing apparatus appropriate for forming the material of its volume. Appropriate filtration can be used to remove any contaminants or other components that do not dissolve properly.

[0030] A coating material can be formed by depositing a precursor solution onto a selected substrate and subsequent processing. Using the precursor solutions described herein, some degree of hydrolysis and condensation may occur during coating, and subsequent processing steps, such as heating in air, can complete or accelerate post-coating. The substrate generally provides a surface upon which the coating material can be deposited, and the substrate may contain multiple layers, where the surface is related to the uppermost layer. In some embodiments, the substrate surface can be treated to prepare the surface for adhesion of the coating material. The surface can also be cleaned and / or smoothed as needed. A suitable substrate surface can include any reasonable material. Some substrates particularly relevant include, for example, silicon wafers, silica substrates, other inorganic materials such as ceramic materials, polymer substrates such as organic polymers, composites thereof, and combinations thereof across the substrate surface and / or in multiple layers. While wafers, such as relatively thin cylindrical structures, may be advantageous, any reasonable shape can be used. Polymer substrates, or substrates having a polymer layer on a non-polymer structure, may be desirable for certain applications based on lithography performance, or the cost and flexibility of the substrate. Suitable polymers can be selected based on the relatively low processing temperatures that can be used for processing the patternable materials described herein. Suitable polymers include, for example, polycarbonates, polyimides, polyesters, polyalkenes, copolymers thereof, and mixtures thereof. Generally, especially for high-resolution applications, it is desirable for the substrate to have a flat surface. However, in certain embodiments, the substrate may have substantial topography intended for filling or planarization of features for a particular patterning application by resist coating.

[0031] In general, any suitable solution coating process can be used to deliver the precursor solution to the substrate. Suitable coating methods include, for example, spin coating, spray coating, dip coating, knife-edge coating, vapor deposition such as chemical vapor deposition (CVD) or atomic layer deposition (ALD), and printing methods such as inkjet printing and screen printing. In some of these coating methods, a pattern of the coating material is formed during the coating process, but the resolution currently available in printing and other methods is at a much lower level than the resolution available in radiation-based patterning as described herein.

[0032] When patterning is performed using radiation, spin coating can be a desirable method for covering the substrate relatively uniformly, although edge effects may occur. In some embodiments, the wafer can be rotated at speeds of about 500 rpm to about 10,000 rpm, in further embodiments about 1,000 rpm to about 7,500 rpm, and in even further embodiments about 2,000 rpm to about 6,000 rpm. The rotation speed can be adjusted to obtain the desired coating thickness. Spin coating can be carried out in a time of about 5 seconds to about 5 minutes, in further embodiments about 15 seconds to about 2 minutes. Initial low-speed rotation, for example, at 50 rpm to 250 rpm, can be used to spread the majority of the composition across the entire substrate first. Backside rinsing, edge bead removal steps, etc., can be performed using water or other suitable solvent to remove edge beads. A person in the art or with ordinary skill will understand that further ranges of spin coating parameters within the explicitly stated range above will be considered and that they will be within the scope of this disclosure.

[0033] The thickness of the coating can generally be a function of the precursor solution concentration, viscosity, and spin coating rotation speed. In other coating processes, the thickness can generally also be adjusted by selecting coating parameters. In some embodiments, the use of a thin coating may be desirable to facilitate the formation of small, high-resolution features in subsequent patterning processes. For example, the dried coating material may have an average thickness of about 10 microns or less, about 1 micron or less in another embodiment, about 250 nanometers (nm) or less in a further embodiment, about 1 nanometer (nm) to about 50 nm in a further embodiment, about 2 nm to about 40 nm in another embodiment, and about 3 nm to about 35 nm in some embodiments. Those skilled in the art will understand that further ranges of thickness within the above-expressed ranges will be considered and that they will fall within the scope of this disclosure. The thickness can be evaluated using a non-contact method of X-ray reflectivity and / or elliptic polarization based on the optical properties of the film. Generally, the coating is relatively uniform to facilitate processing. In some embodiments, the variation in coating thickness varies by ±50% or less from the average coating thickness, in further embodiments by ±40% or less from the average coating thickness, and in even further embodiments by approximately ±25% or less. In some embodiments, such as very uniform coatings on larger substrates, the evaluation of coating uniformity can be performed excluding a 1-centimeter edge; that is, coating uniformity is not evaluated with respect to the coated portion within a 1-centimeter edge. Those skilled in the art will understand that further ranges within the explicitly stated ranges described above will be considered and that they will fall within the scope of this disclosure.

[0034] In many coating processes, evaporation can occur due to the coating process itself, as droplets or other forms of the coating material are formed, and evaporation is stimulated by a larger surface area and / or movement of the solution. As the solvent decreases, the concentration of chemical species in the material increases, and therefore the viscosity of the coating material tends to increase. One objective during the coating process may be to remove enough solvent to stabilize the coating material for further processing. During coating or subsequent heating, the coating species can form a chemically modified coating material through reaction with air, hydrolysis, or condensation.

[0035] Generally, before exposure to radiation, the coating material can be exposed in the presence of atmospheric moisture and optionally heated to hydrolyze the hydrolyzable bonds to the metal in the precursor composition, and / or further remove the solvent to promote densification of the coating material. After in-situ hydrolysis, the coating material can generally form a polymeric metal oxo-hydroxo and / or carboxylate network based on the bonding of oxo-hydroxo and / or carboxylate ligands to the metal (these metals also have several alkyl ligands), or it can form a molecular solid composed of polynuclear metal oxo / hydroxo and / or carboxylate species having alkyl ligands.

[0036] In the hydrolysis / solvent removal process, the exact stoichiometry of the heated coating material and / or the specific amount of solvent remaining in the coating material may or may not be quantitatively controlled. Furthermore, the formulas and compositions shown herein may include some additional water, either directly bonded to Sn or as hydrogen-bonded components of the network. Generally, experimental evaluation of the properties of the resulting coating material can be performed to select effective processing conditions for the patterning process. While heating may not be necessary for a successful process, it may be desirable to heat the coated substrate to speed up the process, and / or to improve process reproducibility, and / or to promote the evaporation of hydrolysis byproducts. In embodiments where heat is applied to remove the solvent during pre-exposure baking, the coating material may be heated to a temperature of about 45°C to about 250°C, and in further embodiments, about 55°C to about 225°C. Heating for solvent removal can generally be performed for at least about 0.1 minutes, in further embodiments, about 0.5 minutes to about 30 minutes, and in further embodiments, about 0.75 minutes to about 10 minutes. Those skilled in the art will understand that further ranges of heating temperatures and times within the explicitly stated range above will be considered and will fall within the scope of this disclosure. As a result of heat treatment, hydrolysis, and densification of the coating material, the coating material can exhibit an increase in refractive index and radiation absorption without significantly impairing contrast.

[0037] After condensation, drying, and possibly hydrolysis, fine patterns can be formed on the coating material using radiation. As mentioned above, the composition of the precursor solution, and the corresponding composition of the coating material, can be designed to adequately absorb the desired form of radiation, with particular interest in EUV radiation. By absorbing radiation, energy is obtained that can break the bonds between the metal and the alkyl ligands, thereby rendering at least some of the alkyl ligands unavailable for stabilizing the material. In the case of alkyltin ligands, the modification caused by radiation may not be very clear, but good patterning properties can be obtained depending on the composition. Similarly, radiation absorption can also lead to the breakdown of bonds between the metal and the carboxylate ligands, and / or the decomposition of the carboxylate ligands. Radiolysis products containing alkyl ligands or other fragments may or may not diffuse from the film, depending on the variables of the process and the type of such products. Upon absorption of a sufficient amount of radiation, the exposed coating material condenses, i.e., forms an enhanced metal oxo-hydroxo network, which may contain further water absorbed from the ambient atmosphere. Radiation can generally be emitted according to a selected pattern. The radiation pattern is mapped onto a corresponding pattern or latent image in a coating material having irradiated and unirradiated regions. The irradiated region includes chemically altered coating material, while the unirradiated region generally includes the as-formed coating material. As described later, the coating material can be developed to remove the unirradiated coating material or selectively remove the irradiated coating material to form very smooth edges.

[0038] Radiation can generally be directed onto a coated substrate via a mask, or the radiation beam can be controlled to scan across the entire substrate. Generally, the radiation can include electromagnetic radiation, electron beams (beta rays), or other suitable radiation. Generally, electromagnetic radiation can have a desired wavelength or wavelength range, such as visible light, ultraviolet light, or X-rays. The resolution achievable with a radiation pattern is generally determined by the wavelength of the radiation, and higher resolution patterns can generally be achieved with shorter wavelength radiation. Therefore, the use of ultraviolet light, X-rays, or electron beams may be desirable, especially to achieve high-resolution patterns.

[0039] According to the international standard ISO 21348 (2007) (incorporated herein by reference), ultraviolet light extends between wavelengths of 100 nm and less than 400 nm. A krypton fluoride laser can be used as a source of 248 nm ultraviolet light. The ultraviolet range can be further divided in several ways under approved standards, for example, into extreme ultraviolet (EUV) from 10 nm to less than 121 nm, and far ultraviolet (FUV) from 122 nm to less than 200 nm. The 193 nm line from an argon fluoride laser can be used as a radiation source in FUV. EUV light at 13.5 nm is used in lithography, and this light is generated from a plasma source of Xe or Sn excited using a high-energy laser or discharge pulse. Soft X-rays can be defined as from 0.1 nm to less than 10 nm.

[0040] The amount of electromagnetic radiation can be characterized by its fluence or dose, which is defined by integrating the radiant flux over the exposure time. A suitable radiation fluence is approximately 1 mJ / cm². 2 ~Approx. 175mJ / cm 2 In further embodiments, approximately 2 mJ / cm² 2 ~Approx. 150mJ / cm 2 In further embodiments, approximately 3 mJ / cm² 2 ~Approx. 125mJ / cm 2This may be the case. Those skilled in the art will understand that further ranges of radiation fluence within the explicitly stated range above will be considered and that they will fall within the scope of this disclosure.

[0041] Based on the design of the coating material, a significant contrast in material properties can exist between the irradiated area having the condensed coating material and the unirradiated coating material having substantially intact organic or carboxylate ligands. In embodiments where post-irradiation heat treatment is used, the post-irradiation heat treatment can be performed at temperatures of about 45°C to about 250°C, in further embodiments about 50°C to about 190°C, and in further embodiments about 60°C to about 175°C. Post-exposure heating can generally be performed for at least about 0.1 minutes, in further embodiments about 0.5 minutes to about 30 minutes, and in further embodiments about 0.75 minutes to about 10 minutes. Those skilled in the art will understand that further ranges of post-irradiation heating temperatures and times within the explicitly stated ranges above can be considered and that they fall within the scope of this disclosure. This high contrast in material properties further facilitates the formation of high-resolution lines with smooth edges in the developed pattern, as described in the following sections.

[0042] In the case of negative imaging, the developer may be an organic solvent, such as the solvent used to form the precursor solution. Generally, the choice of developer may be influenced by the solubility parameters for both irradiated and unirradiated coating materials, as well as the developer's volatility, flammability, toxicity, viscosity, and potential chemical interactions with other processing materials. Suitable developers include, for example, alcohols (e.g., 4-methyl-2-pentanol, 1-butanol, isopropanol, 1-propanol, methanol), ethyl lactate, ethers (e.g., tetrahydrofuran, dioxane, anisole), and ketones (pentanone, hexanone, 2-heptanone, octanone). Development can be carried out for about 5 seconds to about 30 minutes, in further embodiments about 8 seconds to about 15 minutes, and in further embodiments about 10 seconds to about 10 minutes. Those skilled in the art will understand that further ranges within the explicitly stated range above will be considered and that they fall within the scope of this disclosure.

[0043] In addition to the main developer composition, the developer may include further compositions to facilitate the development process. Suitable additives include, for example, viscosity modifiers, solubilizers, or other processing aids. If optional additives are present, the developer may contain additives in a range of about 10% by weight or less, and in further embodiments, about 5% by weight or less. Those skilled in the art will understand that further ranges of additive concentrations within the explicitly stated range above will be considered and that they will fall within the scope of this disclosure.

[0044] When using a weaker developer, such as a diluted organic developer or composition, which results in a slower development rate for the coating, a higher temperature development process can be used to increase the process speed. When using a stronger developer, the temperature of the development process can be lowered to reduce the development rate and / or control the reaction rate. In general, the development temperature can be adjusted between appropriate values ​​that match the volatility of the solvent. Furthermore, developers with dissolved coating material near the developer-coating interface can be dispersed using sonication during development.

[0045] The developer can be applied to the patterned coating material using any reasonable method. For example, the developer can be sprayed onto the patterned coating material. Spin coating can also be used. For automated processing, a paddle method can be used, which involves pouring the developer onto the coating material in a static manner. If desired, the development process can be completed using spin rinsing and / or drying. Suitable rinsing solutions include, for example, ultrapure water, aqueous tetraalkylammonium hydroxide solution, methyl alcohol, ethyl alcohol, propyl alcohol, and combinations thereof. After the image is developed, the coating material is arranged on the substrate as a pattern.

[0046] After the development step is complete, the coating material can be heat-treated to further condense, dehydrate, densify, or remove residual developer from the material. This heat treatment may be particularly desirable in embodiments where the oxide coating material is incorporated into the final device, but it may also be desirable in some embodiments where the coating material is used as a resist and is ultimately removed if stabilization of the coating material is desired to facilitate further patterning. In particular, the baking of the patterned coating material can be carried out under conditions in which the patterned coating material exhibits a desired level of etching selectivity. In some embodiments, the patterned coating material can be heated to a temperature of about 100°C to about 600°C, in further embodiments about 175°C to about 500°C, and in further embodiments about 200°C to about 400°C. This heating can be carried out for at least about 1 minute, in another embodiment about 2 minutes to about 1 hour, and in further embodiments about 2.5 minutes to about 25 minutes. Heating can be carried out in air, vacuum, or in an inert gas environment such as Ar or N2. Those skilled in the art will understand that further ranges of temperatures and times for heat treatments within the explicitly stated range above will be considered and will fall within the scope of this disclosure. Similarly, non-thermal treatments such as blanket UV exposure or exposure to an oxidizing plasma such as O2 can also be used for the same purpose.

[0047] In some embodiments, adjacent linear portions of adjacent structures may have an average pitch (half pitch) of about 60 nm (30 nm half pitch) or less, in some embodiments about 50 nm (25 nm half pitch) or less, and in further embodiments about 34 nm (17 nm half pitch) or less. The pitch can be evaluated by design and can be confirmed by scanning electron microscopy (SEM), for example, by top-down imaging. As used herein, pitch means the spatial periodicity or center-to-center distance of repeating structural elements, and half pitch is half the pitch, as is commonly used in the art. Feature dimensions of a pattern may also be described in terms of the average width of a feature, generally evaluated away from corners, etc. Feature may also mean gaps between material elements and / or material elements. In some embodiments, the average width may be about 25 nm or less, in further embodiments about 20 nm or less, and in further embodiments about 15 nm or less. Those skilled in the art will understand that further ranges of pitch and average width within the above-expressed ranges are considered and fall within the scope of this disclosure. Based on these processes, patterning can generally be applied to the formation of various devices such as electronic integrated circuits by repeating the patterning process to form appropriate layered structures such as transistors or other components.

[0048] Wafer throughput is a substantial limiting factor in the implementation of EUV lithography in high-volume semiconductor manufacturing, and is directly related to the dose required to pattern specific features. Although chemical strategies exist to reduce the imaging dose, a negative correlation is generally observed between the imaging dose required to print the target features and feature size uniformity (LWR, etc.) for EUV photoresists with feature sizes and pitches of <50 nm, thereby limiting the operability of the final device and wafer yield. Patterning capability can be expressed as dose versus gel value. The required imaging dose can be evaluated by forming a number of exposed pads, varying the exposure time stepwise between pads to change the exposure dose. The film can then be developed, and the thickness of the residual resist on all pads can be evaluated, for example, using spectroscopic elliptic polarization. The measured thickness can be normalized against the maximum measured resist thickness and plotted against the logarithm of the exposure dose to form a characteristic curve. The maximum slope of the normalized thickness-to-log dose curve is defined as the photoresist contrast (γ), and the dose value at which the tangent line drawn through this point is 1 is the photoresist dose-to-gel (D) curve. g ) is defined as follows. In this way, common parameters used for characterizing photoresists can be estimated according to Mack, C. Fundamental Principles of Optical Lithography, John Wiley & Sons, Chichester, UK; pp 271-272, 2007. [Examples]

[0049] [Table 2]

[0050] Example 1. ((CH 3 ) 3 SnCH 2 Sn) 12 O 14 (OH) 6 (HCO2 ) 2 Preparation, Analysis, and EUV Exposure of Dodecamer Monomer (C 6 H 5 CC) 3 SnCH 2 Sn(CH 3 ) 3 Synthesis 1.6 g of phenylacetylene and 15 mL of tetrahydrofuran were placed in a 100 mL round-bottom flask equipped with a magnetic stir bar. The solution was cooled to 0 °C, and then 7.7 mL of a 2 M solution of isopropylmagnesium chloride in ether was added dropwise. After adding the isopropylmagnesium chloride solution, the resulting solution was heated to 50 °C for 10 minutes, and then the ether was removed under reduced pressure. The solution after ether removal was cooled and added dropwise at -40 °C to a solution of SnCl2 (1.0 g) in tetrahydrofuran (15 mL). The mixture was warmed to 25 °C, stirred for 14 hours, and then (chloromethyl)trimethylstannane (2 g) was added. The solution was then stirred at 25 °C for 1 hour and subsequently concentrated to 4 mL under reduced pressure. Ether (20 mL) was added to the concentrated solution to form a precipitate, which was collected by filtration. The precipitate was washed with ether to obtain 2.5 g of (C6H5CC)3SnCH2Sn(CH3)3 (Figure 1) as a white powder. This product can be further purified by recrystallization from hydrocarbon solvents such as pentane or hexane. The -CH2Sn(CH3)3 group in this monomer structure becomes the R group of the general dodecamer structure. The product was characterized by NMR: 119 Sn NMR (500 MHz, CDCl3) δ 24.42, -220.74.

[0051] Dodecamer ((CH 3 ) 3 SnCH 2 Sn) 12 O 14 (OH) 6 (HCO 2 ) 2 PreparationIn a 10 mL round-bottom flask fitted with a magnetic stirring bar, 1 g of (trimethylstannanyl)-tris(phenylethynyl)stannane synthesized above, 8 mL of tetrahydrofuran, and 0.1 mL of water were added. The solution was stirred at room temperature for 3 days. After 3 days, 0.04 mL of formic acid was added, and the resulting solution was stirred for 10 minutes. Next, the solution was concentrated under reduced pressure, followed by the addition of ether (5 mL) to form a slurry. The precipitate was collected by filtration and dried under reduced pressure to obtain 0.3 g of ((CH3)3SnCH2Sn) 12 O 14 (OH)6(HCO2)2 was obtained as a white powder. The product was characterized by NMR: 119 Sn NMR (500 MHz, CDCl3) δ19.7, -255.4, -457.16. X-ray diffraction peaks were obtained from the powder, indicating that the powder is crystalline.

[0052] Film Deposition and EUV Contrast The 0.1142 g of dodecimal solid obtained by the above synthesis was dissolved in 12 mL of chloroform (HPLC > 99.8%) by stirring to form a photoresist coating solution with a total Sn concentration of 0.06 M.

[0053] A thin film was deposited on a silicon wafer (100 mm in diameter) with a native oxide surface. A 0.06 M precursor solution was supplied onto the substrate by pipette, spin-coated at 2000 rpm, and then baked on a hot plate at 100°C for 2 minutes. The film thickness was measured to be 29 nm by elliptic polarization spectroscopy.

[0054] Using EUV light on a Dose Calibration Tool (DCT) at Lawrence Berkeley National Laboratory, 50 circular pads, each approximately 500 μm in diameter and arranged in a straight line, were projected onto a wafer. The exposure time for each pad was adjusted to supply a gradually increasing EUV dose (8% exponential step size) to each pad. Next, the resist and substrate were subjected to post-exposure baking (PEB) on a hot plate for 2 minutes at a selected temperature within the range of 140-200°C. The exposed and baked film was then immersed in 2-heptanone for 15 seconds and washed for another 15 seconds with the same developer to form a negative image, i.e., to remove unexposed and low-dose areas of the coating. The process was completed with a final hot plate bake at 150°C for 2 minutes. The residual resist thickness of the exposed pads was measured using a JAWoollam M-2000 Spectroscopic Ellipsometer. Figure 2 shows the measured thickness versus dose for each pad of four wafers subjected to PEB in the temperature range of 140-200°C. Characteristic curves for each process condition can be created by normalizing the thickness against the maximum measured resist thickness and plotting the normalized value versus the logarithm of the exposure dose. The maximum slope of the normalized thickness versus log dose curve is defined as the photoresist contrast (γ), and the intersection of the maximum resist thickness and the tangent to the point of maximum slope is defined as the dose versus gel (Dg). In this way, common parameters for evaluating photoresist performance can be determined, and Mack, C. (2007) Introduction to Semiconductor Lithography, in Fundamental Principles of Optical Lithography: The Science of Microfabrication, John Wiley & Sons, Ltd, Chichester, UK is referenced. Table 2 shows ((CH3)3SnCH2Sn) 12 O 14 This document summarizes the contrast and Dg values ​​of photoresists for (OH)6(HCO2)2 at four PEB temperatures.

[0055]

Table 3

[0056] Example 2. (t-BuSn) 12 O 14 (OH) 6 (HCO 2 ) 2 Preparation and Characterization The dodecamer (t-BuSn) was prepared from the monomer phenylacetylide of t-BuSn(CCPh)3 12 O 14 (OH)6(HCOO)2 as follows. A 2 L round bottom flask (RBF) was purged with nitrogen and charged with 308 g of t-BuSn(NMe2)2 dissolved in 500 mL of pentane. A bubbler was attached to the RBF to pass through a trap containing an aqueous acetic acid solution. While dropping a slight excess of phenylacetylene (337 g, 3.3 equivalents), the temperature was maintained below 40 °C using an ice bath. The solution was reacted overnight, and then a crystalline precipitate was formed. The t-BuSn(CCPh)3 crystals were collected and recrystallized in pentane (yield 92%).

[0057] A 100 mL round bottom flask was charged with 6 g of t-BuSn(CCPh)3, 60 mL of tetrahydrofuran, and 0.6 mL of water. After homogenization, the solution was aged for 3 days, and after that time, crystals were formed. The solution was heated to boiling, and then formic acid (118 mg) was dropped in, and a precipitate was formed. The slurry was filtered while hot and recrystallized in 25 mL of methanol at -20 °C (yield 80%).

[0058] Single crystals were grown by recrystallization of the above clusters in n-propanol. Figure 3 shows the molecular structure of the (t-BuSn) 12 O 14 (OH)6(HCO2)2 cluster determined by single crystal X-ray diffraction. Figure 4 shows the 1 H (above figure) and 119 Sn (below figure) NMR spectra of the cluster in MeOH-d4.119 The signals at -337.03 ppm and -523.57 ppm in the Sn spectrum correspond to the five-coordinate and six-coordinate Sn atoms in the molecular structure, respectively.

[0059] A small amount of (t-BuSn) 12 O 14 (OH)6(HCO2)2 (approximately 1% by mass) was dissolved in a mobile phase of 0.5% acetic acid in methanol, and then injected into an Agilent 6510 QTOF mass spectrometer. Figures 5 and 6 show (t-BuSn) 12 O 14 The peak shown corresponds to the (OH)6(O2CH)2 fragment: (t-BuSn) 12 O 14 (OH)6 2+ [1217u], (t-BuSn) 12 O 15 (OH)5 1+ [2434u], and (t-BuSn) 12 O 14 (OH)6·2[H2O][HOCH3][HCOOH] + [2548u].

[0060] Example 3. (t-BuSn) 12 O 14 F 8 and (t-BuSn) 12 O 14 (OH) 8-x F x (0 < x < 8) Preparation, Analysis, and EUV Exposure. Synthesis In a 20 mL round-bottom flask, 0.5 g of the dodecamer (t-BuSn) obtained in the synthesis of Example 2 was dissolved in 10 mL of methanol. 12 O 14 (OH)6(HCO2)2 was added. Approximately 7.3 parts (0.25 g) of triethylamine hydrofluoric acid per dodecamer were added, and the solution was allowed to stand. After one week, crystals were recovered in 10% yield. (t-BuSn) 12 O 14 F8(Sn 12 C48 H 108 F8O 14 Analytical calculations for ): C, 23.2; H, 4.4; F, 6.1. Result: C, 23.3; H, 4.4; F, 6.0. Adding less than 2.67 parts of triethylamine trihdydrofluoride per dodecamer produces a product with a smaller F:Sn ratio.

[0061] Mass Spectral Analysis The synthesized product was dissolved in methanol (approximately 1% by mass) and injected into an Agilent 6510 QTOF mass spectrometer. Figure 7 shows peaks corresponding to chemical species containing a certain distribution of fluorine and oxygen in the dodecamer. The signal with the highest intensity is that of a single ionized deprotonated cluster [(t-BuSn)]. 12 O 15 (OH)F5] + This matches. The NMR spectrum is shown in Figure 8: NMR Spectrum . CDCl3 1 H, 19 F, 119 SnNMR (400 MHz) is (t-BuSn) 12 O 14 It shows a signal consistent with the F8 dodecamer.

[0062] Contrast of Coating Solution, Film Deposition, and EUV Exposure The fluorinated dodecamer synthesis product was dissolved in chloroform (0.035 M Sn), coated onto an SiO2 / Si wafer by spin coating at 1500 rpm, baked at 100°C, and exposed on an EUV Dose Contrast Tool at Lawrence Berkeley National Laboratories according to the procedure described in Example 1. After exposure, the film was baked at a selected temperature between 140 and 200°C (each sample specified in the figure has a specific temperature) and then developed in 2-heptanone. The thickness of each exposure pad was optically evaluated and then plotted against the exposure dose to determine the contrast value (Figure 9). Table 3 shows (t-BuSn) 12 O 14 Regarding F8, the derived parameter D was obtained from Figure 9. gThis summarizes D0 and contrast. D0 corresponds to the starting dose for the initial increase in the film thickness of the negative resist.

[0063] [Table 4]

[0064] Example 4. (t-BuSn) 12 O 14 (OH) 6 (HCOO) 2 Preparation and Film Deposition of Resist Based on (t-BuSn) was prepared in Example 2 by dissolving 1.4735 g of Sn decidomer in 100 mL of 10% v / v formic acid in methyl isoamyl ketone. 12 O 16 A 0.070 M Sn solution of (OH)6(HCO2)2 was prepared. Formic acid was added to stabilize the solution and improve its solubility and coating quality.

[0065] A circular silicon wafer with a native oxide surface, measuring 10.2 cm in diameter, was used as the substrate for film deposition. A dodecamer film was spin-coated onto the Si wafer at 1500 RPM for 45 seconds. The selected wafer was then baked at 100°C for 120 seconds. The film thickness after coating and baking was measured by elliptic polarization and was approximately 20 nm. All films showed a root mean square surface roughness of <0.5 nm, as measured by atomic force microscopy.

[0066] Example 5. (t-BuSn) 12 O 16 (OH) 2 (HCO 2 ) 2 EUV Exposure Contrast and Line-Space Imaging of Dodecamer A 300 mm Si wafer having a native oxide surface was coated with the resist prepared in Example 4. The film was spin-coated at 1500 RPM and baked at 100°C for 20 seconds. The film was then exposed to extreme ultraviolet radiation on an ASML NXE:3300B scanner. A contrast array was formed in the film by projecting an 11×11 array of pads with increasing EUV photon dose for subsequent pads. A repeating pattern of 16 nm lines on a 32 nm pitch was also projected using dipole 90x illumination and a numerical aperture of 0.33. The exposed resist film and substrate were then subjected to post-exposure bake (PEB) on a hot plate in air at a selected temperature between 120°C and 180°C for 2 minutes. After PEB, the film was developed in 2-heptanone for 15 seconds and washed for another 15 seconds with the same developer to form a negative image, i.e., the unexposed areas of the coating were removed during development. After development, the film was baked on a hot plate at 150°C in air for a final 5 minutes.

[0067] Line-space patterns were imaged using a Hitachi CG5000 CD-SEM. Figure 10 shows the relationship between (t-BuSn) and PEB temperature. 12 O 14 The image shows resist lines formed using (OH)6(HCO2)2. Table 4 summarizes the extracted doses for the pattern size and LWR. The contrast sequence was analyzed by measuring the residual thickness of each exposed and developed pad using elliptic polarization. Figure 11 shows the logarithm of the thickness versus exposure dose of each pad, normalized to the initial resist film thickness, and the characteristic curves at PEB temperatures between 120°C and 180°C are shown. The resulting curves clearly show the negative contrast formed by exposure, with the residual pad thickness of each resist film being almost 0 nm at low doses, then increasing non-linearly, and the dose versus gel (D g It reaches its maximum at ). The dose required to initiate a change in development rate is clearly shown to decrease as a function of PEB. Table 4 shows D at each PEB temperature. g The derived contrast values ​​are also summarized.

[0068] [Table 5]

[0069] The embodiments described herein are intended to be descriptive and not limiting. Further embodiments are within the scope of the claims. Furthermore, while the invention has been described with reference to specific embodiments, those skilled in the art will understand that modifications are possible in form and detail without departing from the intent and scope of the invention. Any references to the above documents are limited so as not to refer to subject matter contrary to the express disclosure herein. To the extent described herein, where a particular structure, composition, and / or process has components, elements, components, or other parts, it should be understood that the disclosure herein includes embodiments comprising such particular components, components, or other parts, or combinations thereof, which may include further features that do not alter the fundamental nature of the subject matter as suggested in the discussion unless otherwise specifically shown.

Claims

1. (QSn) ｎ O ３ｎ／２－１／２ｘ－１／２ｙ F ｘ (OH) ｙ A radiation-patternable coating comprising a composition represented by 1 ≤ n ≤ 12, (0 < x + y ≤ 8), x > 0 (wherein Q is a hydrocarbyl group having 1 to 16 carbon atoms and optionally substituted with a heteroatomic functional group, and Q forms an Sn-C bond).

2. The radiation-patternable coating according to claim 1, wherein Q is a linear, cyclic, or branched alkyl group, or a combination thereof.

3. The radiation-patternable coating according to claim 1 or 2, wherein Q is methyl, ethyl, propyl, pentyl, isopropyl, tert-butyl, sec-butyl, isobutyl, tert-amyl, cyclopropyl, cyclobutyl, cyclopentyl, or a combination thereof.

4. The radiation-patternable coating according to claim 1 or 2, wherein Q is a branched alkyl group or a cycloalkyl group.

5. The aforementioned Q is a tert-butyl group (-C(CH) ３ ) ３ A radiation-patternable coating according to claim 1 or 2, wherein the coating is as described above.

6. The radiation-patternable coating according to claim 1 or 2, wherein Q is a linear alkyl group, a branched alkyl group, a cyclic alkyl group, an aryl group, an olefin group, an alkynyl group, a heteroatom functional group-substituted hydrocarbyl group, or a combination thereof.

7. The dose of patterned EUV radiation irradiated onto the coating is 1 mJ / cm². ２ ~175 mJ / cm² ２ A radiation-patternable coating according to claim 1 or 2.

8. The radiation-patternable coating according to claim 1 or 2, wherein the coating has a post-development contrast of 3.1 to 10.0 after exposure to EUV radiation and development using 2-heptanone as a developer for 5 seconds to 30 minutes.

9. (QSn) ｎ O ３ｎ／２－１／２ｘ－１／２ｙ F ｘ (OH) ｙ A radiation-patternable coating comprising a fluorinated organotin oxo composition containing a hydrolysis product of a composition represented by 1 ≦ n ≦ 12, (0 < x + y ≦ 8), x > 0 (where Q is a hydrocarbyl group having 1 to 16 carbon atoms and optionally substituted with a heteroatom functional group).

10. The radiation-patternable coating according to claim 9, further comprising tin crosslinked with hydroxo(-OH) groups.

11. A radiation-patternable coated substrate comprising the radiation-patternable coating described in claim 9.

12. The coated substrate according to claim 11, wherein the substrate includes a silicon wafer.

13. The coated substrate according to claim 11, wherein the radiation-patternable coating comprises a tin-oxo-hydroxo network containing tin bonded by alkyl groups and further crosslinked by oxo(O) groups and hydroxo(-OH) groups, wherein at least some of the oxo and hydroxo groups are substituted with fluorine.

14. The coated substrate according to any one of claims 11 to 13, wherein the radiation-patternable coating has an average thickness of 1 nm to 50 nm.

15. The coated substrate according to any one of claims 11 to 13, wherein the radiation-patternable coating has an average thickness of 3 nm to 35 nm.

16. A fluorinated organotin composition is deposited on a substrate to form a radiation-patternable coating having tin bonded by alkyl groups and fluorides, and further crosslinked by oxo(O) groups. Includes, A method for forming a radiation-patternable coating on a substrate, wherein the fluorinated organotin composition is represented as (QSn)n O 3n / 2-1 / 2x-1 / 2y F x (OH) y, 1 ≤ n ≤ 12, (0 < x + y ≤ 8), x > 0 (wherein Q is a hydrocarbyl group having 1 to 16 carbon atoms and optionally substituted with a heteroatom functional group, or an alkyltin group having the structure -CH2Sn(R1 R2 R3) and having 4 to 15 total carbon atoms, R1, R2, and R3 are independently alkyl groups having 1 to 5 carbon atoms, and Q forms an Sn-C bond).

17. The method according to claim 16, wherein the substrate includes a silicon wafer.

18. The aforementioned Q is a tert-butyl group (-C(CH) ３ ) ３ The method according to claim 16.

19. The aforementioned Q is -CH ２ Sn(CH ３ ) ３ The method according to claim 16.

20. The fluorinated organotin composition is (QSn) １２ O １４ F ｘ (OH) ８－ｘ The method according to claim 16, comprising a composition represented by (0 < x < 8) (wherein Q is an alkyl group having 1 to 16 carbon atoms).

21. The fluorinated organotin composition is (QSn) １２ O １４ F ８ The method according to claim 16, comprising a composition represented by the formula (wherein Q is an alkyl group having 1 to 16 carbon atoms).

22. The method according to any one of claims 16 to 21, wherein the deposition comprises depositing a photoresist composition comprising an organic solvent and the fluorinated organotin composition onto the substrate.

23. The method according to any one of claims 16 to 21, wherein the deposition includes spin coating.

24. The method according to any one of claims 16 to 21, wherein the radiation-patternable coating has a radiation-sensitive Sn-C bond.

25. The method according to any one of claims 16 to 21, wherein the radiation-patternable coating comprises a tin oxo-hydroxo network.

26. The dose of patterned EUV radiation irradiated onto the radiation-patternable coating is 1 mJ / cm². ２ ~175 mJ / cm² ２ The method according to any one of claims 16 to 21.

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