Patterning composition, precursor and patterning of organotin oxide hydroxides

Abstract

To provide organometallic precursors for formation of high-resolution lithography patterning coatings based on metal oxide hydroxide chemistry.SOLUTION: Organometallic precursor compositions generally comprise ligands readily hydrolyzable by water vapor or other OH source compositions under modest conditions. The organometallic precursors generally comprise a radiation-sensitive organic ligand to tin that can result in a coating that can be effective for high-resolution patterning at relatively low radiation doses and is particularly useful for EUV patterning. The precursor compositions are readily processable under commercially suitable conditions. Solution phase processing with in situ hydrolysis or vapor-based deposition can be used to form the coatings.SELECTED DRAWING: None

Description

[Technical Field]

[0001] Cross-reference of related applications This application claims priority to the concurrently pending U.S. Provisional Patent Application No. 62 / 240,812, filed October 13, 2015, entitled “Organotin Oxide Hydroxide Patterning Compositions With Precursor Vapor Deposition,” and the concurrently pending U.S. Provisional Patent Application No. 62 / 297,540, filed February 19, 2016, entitled “Precursor Compositions for Organotin Oxide Hydroxide Photoresist Flims,” both of which are incorporated herein by reference.

[0002] The present invention relates to a precursor composition that can be coated and hydrolyzed in situ to form a coating comprising an organotin oxide hydroxide. The present invention further relates to a radiosensitive organotin oxide hydroxide coating that can be effectively patterned using UV light, EUV light, or electron beam irradiation to form a high-resolution pattern having low linewidth roughness. [Background technology]

[0003] To form semiconductor-based devices and other electronic devices or other complex microstructures, materials are generally patterned to integrate the structure. Therefore, these structures are typically formed through an iterative process of deposition and etching, where patterns are formed from various materials. In this way, many devices can be formed in a small area. Some technological advancements involve reducing the mounting area for devices, which can be desirable for improving performance.

[0004] Organic compositions can also be used as radiation-patterned resists, and the chemical structure of the organic composition can be altered to match the pattern using radiation patterns. For example, in the process of forming patterns on semiconductor wafers, it is necessary to lithographically transfer a desired image from a thin film of radiation-sensitive organic material. Patterning a resist generally involves several steps, such as exposing the resist to a selected energy source, for example, through a mask, to record a latent image, and then developing it to remove selected areas of the resist. In the case of positive resists, the exposed areas can be transformed to allow for selective removal of such areas, whereas in the case of negative resists, unexposed areas can be removed more easily.

[0005] Generally, a pattern is developed using radiation, a reactive gas, or a liquid solution to selectively remove the highly sensitive parts of the resist, while the rest of the resist acts as an etching-resistant protective layer. Liquid developers can be particularly effective in developing latent images. The substrate can be selectively etched through a window or gap in the remaining area of ​​the protective resist layer. Alternatively, material can be deposited in the exposed area of ​​the substrate beneath through the developed window or gap in the remaining area of ​​the protective resist layer. Finally, the protective resist layer is also removed. This process can be repeated to form further layers of material to be patterned. The material can be deposited using chemical vapor deposition, physical vapor deposition, or other desired methods. For example, further processing steps such as the deposition of conductive material or the injection of dopants can also be used. In the fields of microfabrication and nanofabrication, features in integrated circuits have become extremely small for the purpose of achieving high integration density and improving circuit functionality. [Overview of the project] [Means for solving the problem]

[0006] In a first aspect, the present invention relates to a coating solution comprising an organic solvent, a first organometallic composition, and a metal compound having a hydrolyzable ligand-metal bond. In some embodiments, the first organometallic composition can be represented by the formula R z SnO (2-(z / 2)-(x / 2)) (OH) x (where 0 < z ≦ 2 and 0 < (z + x) ≦ 4), the formula R n SnX 4-n (where n = 1 or 2), or a mixture thereof, where R is a hydrocarbyl group having 1 to 31 carbon atoms, and X is a ligand having a hydrolyzable M-X bond. The hydrolyzable metal compound can be represented by the formula MX’ n , where M is a metal selected from Groups 2 to 16 of the Periodic Table of the Elements, X’ is a ligand having a hydrolyzable M-X’ bond or a combination thereof, and n is determined from the valence of the metal and the charge of the ligand.

[0007] In a further aspect, the present invention relates to a coating solution comprising an organic solvent, at least about 10 mole percent of a first organometallic composition based on the total metal content, and at least 10 mole percent of a second organometallic composition based on the total metal content. In some embodiments, the first organometallic composition can be represented by the formula R z SnO (2-(z / 2)-(x / 2)) (OH) x (where 0 < z ≦ 2 and 0 < (z + x) ≦ 4), the formula R n SnX 4-n (where n = 1 or 2), or a mixture thereof, where R is a hydrocarbyl group and Sn-X is a hydrolyzable chemical bond. The second organometallic composition can be represented by the formula R’ y SnX’ 4-y (where y = 1 or 2), where R’ is a hydrocarbyl group different from R, and X’ is a ligand having a hydrolyzable Sn-X’ bond that is the same as or different from X.

[0008] In another embodiment, the present invention relates to a method for forming a radiation-patternable coating, the method comprising the step of exposing a precursor coating on a substrate to water vapor, the precursor coating comprising a first organometallic composition and a second hydrolyzable composition. The first organometallic composition is of formula R z SnO (2-(z / 2)-(x / 2) (OH) x (Here, 0 <z≦2および0<(z+x)≦4である)またはR’ n Sn 4-n It can be represented by (where n=1 or 2), where R and R' are independently hydrocarbyl groups having 1 to 31 carbon atoms. Its second hydrolyzable composition is given by formula R'' y SnX' 4-y A second organometallic composition or inorganic composition ML represented by (wherein y=1 or 2, and R'' is different from R', and X' is a ligand having a hydrolyzable Sn-X' bond, which is either the same as or different from X) v (where v is 2 ≤ v ≤ 6, and L is a ligand having a hydrolyzable ML bond that is identical or different to X and X'). In some embodiments, the exposure step results in hydrolysis of the precursor coating compound, ((R or R') a R" b )SnO (2-((a+b) / 2)-(w / 2)) (OH) w (where 0 < (a + b) ≤ 2 and 0 < (a + b + w) < 4) or y((R or R') a R" b )SnO (2-((a+b) / 2)-(w / 2)) (OH) w ·zMO ((m / 2)-l / 2) (OH) l (Here, 0 < (a + b) ≤ 2 and 0 < (a + b + w) < 4, so m = M m+ The formal valence is such that 0 ≤ l ≤ m, y / z = (0.05 ~ 0.6), and M = M' or Sn, where M' is a metal other than tin from groups 2 to 16 of the periodic table, forming a coating.

[0009] In a further embodiment, the present invention relates to a method for forming a radiation-patternable coating comprising a metal oxo-hydroxo network with a metal cation having an organic ligand having a metal-carbon bond and a metal-oxygen bond, wherein the method involves individually depositing compound R in a deposition chamber sealed from the ambient atmosphere. n Sn 4-n The process involves introducing a first precursor vapor containing (where n=1 or 2, R is a hydrocarbyl group having 1 to 31 carbon atoms, and X is a hydrolyzable or oxidizable ligand) and a second precursor vapor containing an oxygen-containing compound that can be hydrolyzed or oxidized under conditions in a deposition chamber to form a hydrolyzed or oxidized composition. Generally, the substrate may be configured to have a surface that receives the hydrolyzed or oxidized composition.

[0010] In another embodiment, the present invention relates to a coated substrate including a surface and a substrate having a coating on that surface, wherein y(R z SnO (2-(z / 2)-(w / 2)) (OH) w ·zMO ((m / 2)-l / 2) (OH) l (Here, 0 <z≦2であり、0<(z+w)≦4であり、m=M m+ The present invention relates to a substrate containing an organometallic composition represented by a formal valency of (0 ≤ l ≤ m, y / z = (0.05 ~ 0.6), and M = M' or Sn, where M' is a non-tin metal from groups 2 to 16 of the periodic table, and R is a hydrocarbyl group having 1 to 31 carbon atoms).

[0011] Furthermore, the present invention relates to a substrate and approximately 6.125 mJ / cm² 2 The following are dose-to-gel values ​​(D g The present invention relates to a radiosensitive coating containing an alkyl metal oxide hydroxide having ).

[0012] Furthermore, the present invention relates to a substrate comprising an inorganic semiconductor layer and a radiation-sensitive coating material along its surface. In some embodiments, the radiation coating material is patterned with EUV light of a wavelength of 13.5 nm in a pattern of 16 nm lines at a pitch of 32 nm, resulting in a radiation dose of approximately 8 mJ / cm². 2 ~about 25mJ / cm 2 Depending on the dose, a critical dimension of 16 nm can be achieved with a line width roughness of approximately 4 nm or less. The radiation-sensitive coating material may contain a metal such as Sn, and may contain at least 5 weight percent of metal, or at least about 20 weight percent of metal in other embodiments. [Brief explanation of the drawing]

[0013] [Figure 1] This is a schematic perspective view of a radiation patterned structure with latent images. [Figure 2] This is a side view of the structure shown in Figure 1. [Figure 3] Figure 1 is a schematic perspective view of the structure after developing the latent image, removing the unirradiated coating material, and forming a patterned structure. [Figure 4] Figure 3 is a side view of the patterned structure. [Figure 5] Figure 1 is a schematic perspective view of the structure after developing the latent image, removing the irradiated coating material, and forming the patterned structure. [Figure 6] Figure 5 is a side view of the patterned structure. [Figure 7] This is a scanning electron microscope (SEM) image of a fixed pattern formed on a substrate with a line spacing of 16.7 nm, using an EUV dose of 56 mJ / cm2. [Figure 8] This is a plot of the film thickness after exposure and development as a function of EUV dose, formed from 50 circular pads with a diameter of 500 microns, which were exposed at stepwise doses using radiation resist on a substrate coated by in situ hydrolysis as described herein. [Figure 9] This is a plot of two FTIR spectra comparing a film formed using solution-based hydrolysis and a film formed by in-situ hydrolysis during coating. [Figure 10] This is a set of plots using EUV contrast curves, including a function of dose, for coatings formed using three different amounts of Sn(NMe2)4 in a radiosensitive coating before in-situ hydrolysis. [Figure 11] This is a set of micrographs of five patterned coatings formed using the described compositions and irradiation doses. [Figure 12] This plot shows the linewidth roughness (LWR) as a function of dose-size value for six resist compositions patterned with 16 nm lines at a 32 nm pitch using 13.5 nm wavelength EUV light, employing dose-size values ​​to achieve a limiting dimension of 16 nm. [Figure 13] This is a set of plots of EUV contrast curves, including a function of dose, for five different coatings formed by varying the amount of methyl ligands as radiosensitive groups. [Figure 14] This is a set of plots of the spatial limit dimensions as a function of irradiation dose for coatings with three different amounts of methyl ligands. [Figure 15] This is a set of three SEM microscope images of patterns formed by varying the EUV irradiation dose. [Modes for carrying out the invention]

[0014] By using an organotin pattern-forming composition having an alkyl-Sn bond with a selected ratio of radiation sensitivity and / or a tin precursor that does not contain a selected amount of radiation-sensitive ligands, improved pattern-forming performance can be obtained at a lower irradiation dose, and by using in-situ solvolysis of the precursor composition, for example hydrolysis, improved processing of coatings that can be pattern-formed by radiation can be achieved. Those coatings that can be pattern-formed by radiation generally include R z SnO (2-(z / 2)-(x / 2)) (OH) x compositions, where 0 < z ≦ 2 and 0 < (z + x) < 4, and R is a radiation-sensitive alkyl ligand, which in some embodiments can exhibit improved low-dose irradiation pattern formation when formed using a selected amount of SnX4 precursor compound for the purpose of modifying the value of z throughout the composition. By using in-situ hydrolysis, effective use of the precursor composition in solution-based processing becomes possible, which would be difficult or impossible to achieve by directly dissolving and depositing an alkyltin oxo-hydroxy composition. As described herein, the processability is improved by creating an R z SnO (2-(z / 2)-(x / 2)) (OH) x composition that can be patterned by in-situ solvolysis. As an alternative to solution-based processing for forming an organotin oxide hydroxide precursor, vapor deposition methods can be useful for depositing certain precursor coatings. Those pattern-forming compositions are particularly useful for forming EUV patterns at a lower dose and can obtain a low linewidth roughness even for small features.

[0015] General formula R z SnO (2-(z / 2)-(x / 2)) (OH) xOrganotin oxide hydroxides having (where 0 < (x+z) < 4 and z > 0) have been found to provide excellent performance as patterning materials, commonly known as photoresists, when deposited as thin film coatings, exposed to ultraviolet (UV), extreme ultraviolet (EUV), or electron beam irradiation, and developed with a suitable solvent. Previous studies have shown that organotin oxide hydroxides can serve as a base for forming stable precursor solutions, from which resist layers with good irradiation absorption and development rate contrast can be formed. Organotin compositions are effectively used as negative or positive resists. The effectiveness of these compounds for EUV and electron beam resists is described in U.S. Patent No. 9,310,684B2 to Meyers et al., entitled “Organometallic Solution Based High Resolution Patterning Compositions” (which is incorporated herein by reference). Based on today's synthetic approaches, it is considered appropriate to extend these compounds to the value of (x+z) = 4, i.e., 0 < (x+z) ≤ 4. The improved patterning performance discovered using a blend of branched alkyl ligands and alkyltin oxide hydroxide compositions is described in U.S. Patent Application Publication No. 2016 / 0116839A1 (hereinafter referred to as '839) to Meyers et al., entitled “Organometallic Solution Based High Resolution Patterning Compositions and Corresponding Methods” (which is incorporated herein by reference).

[0016] The aforementioned references include one or more R n Sn (4-n) R prepared by pre-hydrolysis of a composition (where n=1 or 2), isolation and purification of its organotin hydrolysates, and dissolution of the oxide hydroxide in a suitable solvent or a mixture thereof.z SnO (2-(z / 2)-(x / 2)) (OH) x The deposition of an organotin oxide hydroxide photoresist film using a coating precursor solution containing the composition has been described. However, the dissolution and coating of pre-hydrolyzed organotin oxide hydroxides presents substantial limitations on the available ligand species, necessitates stoichiometry to avoid the low solubility of one or more hydrolysates, and in some embodiments, the complex hydrolysis process may increase the likelihood of undesirable contaminants being introduced. Furthermore, even if a soluble resist precursor solution can be prepared from the organotin oxide hydroxide precursor composition, undesirable solvents may be required or the morphology of the film may be compromised.

[0017] Many of these constraints are due to the dissolution of one or more suitable R in a suitable solvent or mixture of solvents. n Sn (4-n) It was found that this could be overcome by preparing a resist precursor solution consisting of a compound (where X is a ligand with a hydrolyzable Sn-X bond). n Sn (4-n) If the reactivity with water vapor is sufficiently high, in-situ -MX hydrolysis and condensation in the presence of water are possible, yielding the corresponding oxide hydroxide, as shown in the following general reaction. R n Sn x +xH2O→R n Sn(OH) x +xHX R n Sn(OH) x →R n SnO (2-(n / 2)-(x / 2)) OH x +(x / 2)H2O (Here, 0 < (x + z) ≤ 4). Therefore, R n Sn (4-n) By using a coating solution containing the compound, a wide range of R values ​​can be applied in the actual process. z SnO (2-(z / 2)-(x / 2)) (OH)x The composition can be formed as a photoresist coating. In these methods, during the hydrolysis and condensation processes, the R-Sn moiety is at least partially retained, and the resulting film contains both M-C and M-O bonds.

[0018] In one embodiment of the in-situ hydrolysis process, the precursor R n SnX (4-n) is dissolved in a solvent and optionally applied directly onto a substrate in the presence of water vapor (e.g., humid air) to create a coating, and then further baked in addition or alternatively in the presence of water vapor to form an organotin oxide hydroxide coating. Thus, water vapor for hydrolysis can also be present during coating deposition and / or during a pre-pattern baking step for in-situ hydrolysis. Further, by blending a plurality of R n SnX (4-n) compounds (e.g., SnX4, RSnX’3, R’SnX”3, and R”2SnX2 where R, R’, and R” are the same or different and X, X’, and X” are also the same or different) in a suitable solvent, an R z SnO (2-(z / 2)-(x / 2)) (OH) x film having a selected stoichiometry in the range of 0 < z ≦ 2 and 0 < (x + z) ≦ 4 can be readily deposited. Similarly, a hydrolyzate of mixed ligands containing an organotin oxide hydroxide of R z SnO (2-(z / 2)-(x / 2)) (OH) x (where 0 < (x + z) < 4 and z > 0) and one or more different organotin oxides R’ b SnO (2-(b / 2)-(a / 2)) (OH) a (where 0 < (a + b) < 4 and b > 0) (where R’ ≠ R) can also be prepared in this way. The hydrolyzable R n SnX (4-n) and R’ b SnX (4-b)The compound can be dissolved in a common solvent or solvent mixture and spin-coated onto a substrate for in-situ hydrolysis. In either case, the solubility of the organotin precursor compound in a suitable molecular state is high and it hydrolyzes rapidly, advantageously avoiding solubility limitations that can occur with the hydrolysis product of the target organotin oxide hydroxide and eliminating the need to perform complex and laborious synthetic procedures for isolating the hydrolyzed and partially condensed resist precursor ex-situ. In this method, the preparation of the resist precursor is significantly simplified and desirable compositions with improved performance can be obtained.

[0019] In another embodiment, due to the relatively high vapor pressure and reactivity of many molecular state R n SnX (4-n) compounds, it becomes possible to use vapor deposition methods for depositing thin film photoresists of organotin oxide hydroxides. Possible deposition methods include, for example, physical vapor deposition (PVD), chemical vapor deposition (CVD), atomic layer deposition (ALD), or modified versions thereof. For example, one or more gaseous R n SnX (4-n)A radiosensitive organotin oxide hydroxide coating can be fabricated by introducing a compound into a reaction chamber and reacting it with a co-precursor, such as H2O or its associated decomposition reaction products, either in the gas phase or on the substrate surface. If a hydrolysis reaction subsequently deposits a hydrolyzable compound on the surface, this process can be considered a PVD deposition with in-situ hydrolysis; however, if hydrolysis occurs during a continuous deposition process, it can be considered a CVD process. Similarly, if a hydrolyzable precursor is then adsorbed, chemiadsorbed, or decomposed on the substrate surface, and the remaining film reacts with a second reactive precursor in a multiple deposition / reaction cycle to deposit the corresponding organotin oxide hydroxide, this can be considered an ALD process. Advantages of vapor deposition include reduced defect density in the resist film, improved uniformity of thickness and composition, and conformal and sidewall coatings of the substrate topography.

[0020] It was found that the photoresist performance of organotin oxide hydroxides, such as image formation dose, ultimate resolution, and linewidth roughness (LWR), depends on the composition of the photoresist coating. z SnO (2-(z / 2)-(x / 2)) (OH) x In these photoresist films having compositions (where 0 < (x + z) ≤ 4 and z > 0), both the identification of radiosensitive ligands R and the stoichiometric ratio of R:Sn represented by z can be greatly varied. Generally, the photoresist film can contain radiosensitive ligands R such that the thin film has a molar concentration ratio (z) of radiosensitive ligands to metal cations of about 0.1 to about 2. Resist films of organotin oxide hydroxides having ligand ratios within this range can have multiple R at appropriate stoichiometric ratios. n Sn (4-n)A precursor (where z = 1 or 2) can be prepared by pre-hydrolyzing and then dissolving the hydrolyzate thus obtained in a coating solvent in accordance with solubility and stability constraints. In a certain stoichiometry, particularly 0.1 < z < 1, it has been found that the photoresist composition exhibits advantageous photoresist performance. However, in a photoresist composition where z < 1, processing constraints as described above can be problematic because the solubility in an organic solvent is typically extremely low for the hydrolyzate of inorganic SnO (2-(x / 2)) (OH) x (z = 0) and deviates from the very limited conditions suitable for co-hydrolysis and cluster condensation with specific organotin RSnX3 or R2SnX2 residues. Furthermore, even when such conditions are identified and the hydrolyzate is isolated and dissolved, the stability, stoichiometry, ligand discrimination, and solvent of the precursor solution may be unfavorably restricted with respect to the desired values for handling as an EUV photoresist.

[0021] These processing and compositional constraints can be overcome by adding an easily hydrolyzable SnX4 compound to a precursor coating solution containing one or more pre-hydrolyzed organotin oxide hydroxides or one or more RSnX3 and / or R2SnX2 compounds, which are selected for substantially complete hydrolysis followed by condensation, coating, and evaporation of HX by-products during baking in the presence of water or other suitable sources of oxygen and hydrogen. In this way, it becomes possible to independently adjust both the discrimination of multiple radiation-sensitive ligands and the relative stoichiometry in both the precursor coating solution and the photoresist film over a wide range of ratios of total ligand to metal cation, the constraints regarding the stability and solubility of the solution are relaxed, and the synthesis of the precursor is simplified. Therefore, it is possible to incorporate a suitably selected SnX4 composition into the precursor mixture or process, thereby enabling the vapor deposition of organotin oxide hydroxide using the corresponding composition.

[0022] By relaxing the inherent stability and solubility constraints of organometallic compounds possessing both MC and MO bonds, alternative metal species can be applied to the precursor coating solution or reactive gas mixture using MX'. n It is also possible to add it in the form of, where M is a metal cation selected from group 2 to 16 metals, and n is determined from the valence of the metal cation and the charge of the ligand, and is generally 3 to 6. If M ≠ Sn, the ligand X' is R used in the same formulation. n Sn (4-n) X in the compound may be the same as or different from MX'. In either case, these ligands and MX' n This follows similar criteria, including rapid and substantially complete hydrolysis in the presence of H2O, as well as diffusion and evaporation of the hydrolysis reaction product of the X(X') ligand from the oxide-hydroxyde film. Alternative metal cations incorporated into the organotin oxide-hydroxyde coating in this manner may be advantageous for modulating radiation absorption, film density, metal-ligand thermal decomposition, development rate in a preferred developer, or other desired photoresist properties.

[0023] It had been previously discovered, as described in the '839 application, that the identification and relative stoichiometry of multiple R-Sn residues present in an organotin oxide hydroxide resist film provides improved pattern-forming performance. While the branched alkyl ligands and associated blend compositions described therein are available using at least partially pre-hydrolyzed organotin oxide hydroxide compounds dissolved in solvents, it was recognized that there are significant limitations with respect to ligand identification and stoichiometry in relation to practical processing suitable for commercial use. Many of these limitations relate to the solubility of the hydrolysates. For example, while some mono-organotin hydrolysates, such as n-butyltin oxide hydroxide, exhibit excellent solubility in a wide range of organic solvents, for example... t BuSnO (3 / 2-(x / 2)) (OH) xHydrolyzates of mono-tert-butyltin residues such as t BuSnO (3 / 2-(x / 2)) (OH) x where 0 < x < 3 are often not sufficiently soluble in useful solvents and / or it is difficult to reproduce and / or adjust the desired solution concentration. As shown in the '839 application, using methanol and solvent blends derived therefrom, t solutions of BuSn(NEt2)3 can be prepared, but due to the volatility, flash point and toxicity of methanol, it is an undesirable solvent for use in semiconductor manufacturing. Furthermore, due to the low maximum concentration, limitations occur in the range of available film thicknesses, the composition of the blend precursor formulation, and possible coatings. These limitations are illustrated in the following examples, where high-performance t BuSnO (3 / 2-(x / 2)) (OH) x photoresist films are shown by spin-coating a solution of BuSn(NEt2)3 in 4-methyl-2-pentanol in the presence of water vapor.

[0024] Similarly, due to the low solubility of hydrolyzates such as MeSnO (2-(z / 2)-(x / 2)) (OH) x of mono-methyltin residues, the film thickness and the compositional ranges of the formulation and coating are limited. However, by preparing a resist precursor solution containing MeSnX3 compounds that are easily hydrolyzed and highly soluble, the resulting t BuSnO (3 / 2-(x / 2)) (OH) xIt has been found that depositing a resist film containing methyl tin oxide hydroxide in the form of a blend formulation yields favorable lithographic performance. Importantly, the methods and precursor solutions disclosed herein substantially relax the restrictions on the solvent of the resist precursor solution, making it easier to adjust the stoichiometry of the resist film to achieve useful lithographic performance. A desirable photoresist precursor solution and subsequent film composition comprising a mixture of organotin residues and metal cations having various organic ligands (R, R', R'' etc.) with a wide range of molar ratios relative to each other is thus suitable for multiple hydrolyzable organotin compounds R n Sn (4-n) +R' z SnX' (4-z) +R” a SnX" (4-a) This can be obtained by mixing +... (where 0 ≤ (n, z, a) ≤ 2 and at least one of n, z, a > 0).

[0025] Alternatively, the selected R n Sn (4-n) The compound (where n=0, 1, or 2) may be added to a precursor coating solution containing one or more separately synthesized organotin oxide hydroxide hydrolysates, which is prepared by dissolving the compound in a suitable solvent. Thus, the added R n Sn (4-n) The compound can be hydrolyzed by exposing it to water vapor or a hydroxide residue, and then condensed with the initial organotin oxide hydroxide during the coating and baking steps to form a coating having an alkyl ligand-to-metal ratio determined by the stoichiometry of the precursor compound originally present in the precursor coating solution.

[0026] The selection of ligand (X) associated with the hydrolyzable Sn-X bond in the above-mentioned compounds is crucial for effective solvation, coating, and satisfactory in-situ hydrolysis. A suitable ligand should form a stable bond with Sn even in the absence of Lewis acids and should generally be a strong nucleophile that reacts rapidly with acidic protons to readily desorb or evaporate from the oxide-hydroxyl film during condensation, thereby reducing voids, domain segregation, or other heterogeneity. n Sn (4-n) In the case of a compound, X may be a single, unique ligand; however, in certain embodiments, it may be a combination of multiple different ligands, for example, R n Sn 1 a X 2 b X 3 c X 4 d This may also refer to (where a+b+c+dn=4 and 0≦n≦2). Examples of this type of compound include: t BuSn(NEt2)2(O t Bu), t BuSn(NEt2)(NH2)(O t Bu), t BuSn(NEt2)(O t Bu)2, MeSn(NEt2)(O t Bu)2, MeSn(NEt2)2(O t Bu), ( t Bu)2Sn(NEt2)(O t Bu), Me2Sn(NEt2)(O t Bu), (Me)( t Bu)Sn(NEt2)2, (Me) t Bu)Sn(NEt2)(O t Bu), ( i Pr)( t Bu)Sn(NMe2)(O t Bu), and mixtures thereof.

[0027] The selection of the -X ligand can be determined in part by the identification of the hydrocarbyl ligand R, other hydrolyzable ligands, and the stoichiometric ratio of R:Sn, because the reactivity associated with the hydrolysis or sorbolisis of a given Sn-X residue will vary depending on the overall ligand environment around that metal (involving both steric (kinetic) and electrostatic (thermodynamic) effects).

[0028] One or more types of R n Sn (4-n) Formulations containing the compound (where -X is a short-chain aliphatic dialkylamide-NR'2 or alkoxide-OR' ligand, and R' contains fewer than 10 carbon atoms) have been found to be particularly suitable for these applications. When exposed to atmospheric moisture during the coating and baking processes, these materials undergo rapid hydrolysis and condense with other organotin precursor components as described above, releasing volatile dialkylamines and alcohols to form organotin oxide hydroxides with excellent photoresist properties. Other useful ligands of this type include amides, alkylamides, dialkylamides, alkoxos, aryloxos, azides, imides, and others known to those skilled in the art.

[0029] In some embodiments, when an organotin dialkylamide is dissolved in a protic solvent, such as an alcohol, the tin precursor compound may react with the solvent. Solvoresis, for example, alcoholesis when the solvent is an alcohol, or a similar reaction may occur, potentially leading to metathesis of all or some of the ligands, as shown in the following reaction. R n Sn(NR'2) (4-n) +(4-n)R”OH→R n Sn(OR) (4-n) +(4-n)HNR'2(2)

[0030] Sorbolisis and metathesis reactions like those in Equation 2 are predictable, acceptable, and potentially even more useful, however, the tin species of the reaction products (e.g., tin(IV) alkoxide, R) n Sn(OR) (4-n) The material must possess the necessary properties regarding water reactivity, volatility of hydrolysis by-products, and diffusivity, as well as other properties described herein, and when coated and baked in an environment with appropriate humidity, a suitable oxide-hydroxyl film must be obtained.

[0031] The improved precursors described herein open up further possibilities for rational coating solutions and patternable coating compositions based on in-situ hydrolysis. In-situ hydrolysis provides the possibility of a range of vapor-phase deposition approaches as a suitable alternative to solution-based processing methods. By adjusting the composition of patternable coatings using radiosensitive ligands, improved patterning and good pattern quality have been achieved at lower radiation doses.

[0032] Precursor composition Precursor compositions for forming resist coatings typically contain a tin cation along with a suitable radiosensitive hydrocarbyl stabilizing ligand and additional ligands with hydrolyzable bonds to Sn, selected for processing. To process into a patternable coating, the precursor composition is generally in solution form using a solvent (typically an organic solvent), which can then be converted into a coating by solution coating or a gas-phase based deposition process. The final resist coating is based on metal oxide chemistry, and the precursor solution of the tin cation with alkyl ligands provides a stable solution with good resist properties. The ligands in these precursor solutions are generally selected to provide solution formation and related processing capabilities. As mentioned earlier, by introducing precursor compositions with ligands having hydrolyzable bonds to Sn into precursor solutions, it is possible to improve a series of compositions to form stable solutions, and subsequent hydrolysis is expected to result in a patternable coating using organotin oxide hydroxide materials. It has been found that compositions containing a blend of alkyl ligands, generally having at least one branched alkyl ligand, provide desirable pattern-forming performance.

[0033] Alkyl ligands confer radiosensitivity, and radiosensitivity can be influenced by the specific selection of ligands and their stoichiometric ratio to the metal. Furthermore, these precursor solutions can be designed to achieve desired levels of radiation absorption at selected radiative energies, based on the selection of metal cations and associated ligands. While the range of precursor compositions suitable for the improved processing described herein has been discussed in considerable detail, alkyl tin amide / alkoxy precursor compositions for in-situ hydrolysis will be described in more detail. As previously mentioned, various compounds are described that can provide improved solubility in desirable solvents with good processability for radiosensitive coatings. Novel types of precursors, including at least some in-situ hydrolysis using several gas-phase hydrolysis / oxidation reagents, have enabled a wide range of precursor engineering for forming radiation-patternable coatings.

[0034] Generally, the precursor solution may contain the following: a1 R 1 z1 SnO (3 / 2-z1 / 2-x1 / 2) (OH) x1 +a2 R 2 z2 SnO (3 / 2-z2 / 2-x2 / 2) (OH) x2 +...+b1 R 1 ' y1 Sn 1 4-y1 +b2 R 2 ' y2 Sn 24-y2 +...+c1 SnX 1 '4+c2 SnX 2 '4+...+d1 M 1 X 1 " n1 d2 M 2 X 2 " n2 +... (1) Here, a1+a2+...+b1+b2+...+c1+c2+...+d1+d2+...=1, meaning these parameters correspond to the mole fractions of metal in the precursor composition in the solution, (0≦(a1, a2, ...)≦0.99), (0≦(b1, b2, ...)≦1), (0≦(c1, c2, ...)≦0.6), (0≦(d1, d2, ...)≦0.5), and 0.01<(b1+b2+...+c1+c2+...), and R(R 1 , R 2 , ...) and R'(R 1 ', R 2 ', ...) are independently hydrocarbyl groups or combinations thereof, X(X 1 , X 2 ,...),X'(X 1 ', X 2 ', ...) and X"(X 1 ", X 2 ", ...) are ligands that independently have hydrolyzable bonds to the relevant metal or combination thereof, M 1 M 2 , ... are metal ions other than tin, (0 < (x1, x2, ...) < 3), (0 < (z1, z2, ...) ≤ 2), (1 < (y1, y2, ...) ≤ 3), and n1, n2, ... are M 1 M 2 ...Valence of ions and X 1 ", X 2 "It is determined by the charge of... Generally, M is a metal from Group 2 to Group 16, and for many metals, n is in the range of 2 to 6. Desirable metals for M include Hf, Zr, W, Ta, Co, Ni, In, Sb, Bi, Te, etc. Representative and suitable ML" n Examples of compounds include Zr(OtBu)4, Hf(NMe)4, and In(O iExamples include Pr)3 and Sb(OEt)3, which are commercially available from Sigma-Aldrich, Alfa Aesar, Gelest, Strem Chemical, and other suppliers. In some embodiments, the values ​​of all "a" parameters are zero, and as a result, all ligands are hydrolyzed in situ. In further embodiments, 0.1 ≤ (a1, a2, ...) ≤ 0.90, or 0.2 ≤ (a1, a2, ...) ≤ 0.85, or 0.25 ≤ (a1, a2, ...) ≤ 0.75. In some embodiments, 0.25 ≤ (b1, b2, ...) ≤ 1, or 0.3 ≤ (b1, b2, ...) ≤ 0.95, or 0.35 ≤ (b1, b2, ...) ≤ 0.9. In further embodiments, 0 ≤ (c1, c2, ...) ≤ 0.4, or 0.025 ≤ (c1, c2, ...) ≤ 0.4, or 0.05 ≤ (c1, c2, ...) ≤ 0.35, or 0.1 ≤ (c1, c2, ...) ≤ 0.3, and 0 ≤ (d1, d2, ...) ≤ 0.5, or 0.025 ≤ (d1, d2, ...) ≤ 0.4, or 0.05 ≤ (d1, d2, ...) ≤ 0.3. As is well known to those skilled in the art, further ranges of the “a”, “b”, “c”, and “d” parameters within the ranges expressed above are also conceivable and are included in the disclosure of the present invention. When used herein, the “<” and “≤” symbols implicitly include the concept of corresponding range limits, which are “approximately” specified values ​​within the range of experimental error.

[0035] In summary, the precursor compositions may include one or more compounds comprising a ligand with a hydrolyzable bond to at least one metal and one or more hydrocarbyl ligands that impart radiosensitivity. These compositions are generally designed to be processable by forming a precursor solution using a suitable organic solvent, which will be described below. These precursors are generally processed to obtain desirable patterning performance and good processability.

[0036] In some embodiments, the precursor compositions may include two organotin compounds having different hydrocarbyl ligands, three organotin compounds having different hydrocarbyl ligands, or a mixture of four or more organotin compounds having different hydrocarbyl ligands. In addition, the precursor compositions may include a mixture of a compound having a metal-carbon bond and one or more compounds containing a radiosensitive alkyl ligand having a metal-carbon bond. Generally, in binary or ternary mixtures, the mixture contains at least about 5 mole percent of each component having a distinct hydrocarbyl ligand, at least about 10 mole percent in some embodiments, and at least about 20 mole percent in further embodiments. As is well known to those skilled in the art, further ranges of mole percent of components within the ranges expressed above are also conceivable and are included in the disclosure of the present invention.

[0037] In some embodiments, the precursor composition comprises an R-Sn residue containing a hydrocarbyl ligand and an inorganic metal SnX4 or MX that does not contain an alkyl ligand directly bonded to the metal. n This includes mixtures with compounds. Generally, these mixtures contain at least about 0.5 mole percent of each metal component, at least about 5 mole percent in some embodiments, and at least about 10 mole percent in further embodiments. As is well known to those skilled in the art, further ranges of mixed components within the ranges expressed above are also conceivable and are also included in the disclosure of the present invention. Each component of the precursor composition may be combined in solution, but not separately formed as a solid blend before forming a coating, for example.

[0038] Whether or not one or more distinct hydrocarbyl ligands are present, the R group may be linear, branched (i.e., secondary or tertiary at the metallically bonded carbon atoms), or cyclic hydrocarbyl groups. Each R group individually is an embodiment generally having 1 to 31 carbon atoms, 3 to 31 carbon atoms being secondaryly bonded, and 4 to 31 carbon atoms being tertiary bonded, such as methyl, ethyl, propyl, butyl, and branched alkyl groups. In particular, if the compound is R 1 R 2 R 3 CSnX3(here, R 1 and R 2 However, independently, it is an alkyl group having 1 to 10 carbon atoms, and R 3 However, branched alkyl ligands that can be expressed in alternative terms (which are hydrogen atoms or alkyl groups having 1 to 10 carbon atoms) are preferred. In some embodiments, R 1 and R 2 It is possible to form a cyclic alkyl residue with and R 3 However, it is also possible to further participate in other groups within the cyclic residue. Suitable branched alkyl ligands include, for example, the following: isopropyl(R 1 and R 2 is methyl, and 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, and R 3 (is -CHCH3), sec-butyl (R 1 is methyl, R 2 is -CHCH3, and R 3cyclohexyl, cyclopentyl, cyclobutyl, and cyclopropyl (where is hydrogen). Examples of suitable cyclic groups include, for example, 1-adamantyl (-C(CH2)3(CH)3(CH2)3, or tricyclo(3.3.1.13.7)decane bonded to the metal at the tertiary carbon) and 2-adamantyl (-CH(CH)2(CH2)4(CH)2(CH2), or tricyclo(3.3.1.13,7)decane bonded to the metal at the secondary carbon). In other embodiments, the hydrocarbyl group may include aryl or alkenyl groups, such as benzyl, allyl, or alkynyl groups. In other embodiments, the hydrocarbyl ligand R may consist only of C and H and include various groups containing 1 to 31 carbon atoms. Examples include: linear or branched alkyl ( i Pr, t Bu, Me, n Bu), cycloalkyl (cyclopropyl, cyclobutyl, cyclopentyl), olefin (alkenyl, aryl, allyl), or alkynyl groups, or combinations thereof. In further embodiments, preferred R groups may include hydrocarbyl groups substituted with heteroatom functional groups, such as cyano, thio, silyl, ether, keto, ester, or halogenated groups, or combinations thereof.

[0039] Several suitable metal compositions having the desired ligand structure can be purchased from commercial sources, for example, Alfa Aesar (MA, USA) and TCI America (OR, USA), or other metal-ligand compositions can be synthesized as described below. Precursor compositions with low metal contamination can be synthesized using the methods described herein, preferably based on the use of low-contamination starting materials and appropriate purification methods.

[0040] Desired pattern formation results were obtained using precursor compounds having branched alkyl ligands. However, while the use of mixed alkyl ligands yielded more comprehensive advantages in ligand selection, the individual advantageous pattern formation properties conferred by different ligands, such as dose and linewidth roughness, can be obtained by blending multiple alkyl ligands according to the teachings herein, as described in the examples below. Processing with precursors that are hydrolyzed in situ provides the effective use of tin compounds having methyl ligands in precursor solutions based on a desired solvent. Effective pattern formation using a mixture of tert-butyl ligands and methyl ligands, and hydrolyzable compounds having t-butyl ligands and hydrolyzable SnX4 compounds (X=NMe2 or X=O t A precursor containing a mixture with Bu) is described in the following examples.

[0041] It was found that in mixtures of precursor compounds having different alkyl ligands, the radiation hardening dose can be scaled almost linearly relative to the radiation dose of each individual precursor compound. For branched alkyl ligands, it is generally desirable that the mixture contains at least one branched organic ligand due to the low usable radiation dose. However, it was also found that using mixtures of precursor compounds having different organic ligands can improve line width roughness. While we do not wish to be constrained by theory, the improved line width roughness observed in the mixture compositions can be attributed to the fact that the mixture compositions facilitate etching and do not significantly reduce contrast in the pattern. In this regard, the observation can be extended to mixture compositions containing combinations of organotin compounds supporting branched or unbranched alkyls.

[0042] The X, X', and X'' ligands are generally Lewis bases, and they can react favorably with the acidic protons of water or other Lewis acids via hydrolysis or sorbolisis of the MX, M-X', and MX'' bonds to form readily volatile reaction products. Alternatively, these ligands may react with suitable reagents via oxidation or reduction reactions to form readily volatile reaction products. The ligands generally have an acid dissociation constant (pK) of their conjugate acid. a ) can be classified by, but in some embodiments, the desired ligand is a conjugate acid with a pK higher than about 4. a Therefore, X, X', and X'' generally contain atoms bonded to a metal, such as tin, thereby enabling nucleophilic substitution reactions involving H2O and -OH. The resulting M-OH or M-OH2 ligand then reacts through subsequent condensation or dehydration steps to form an oxide-hydroxyl network.

[0043] Suitable ligands include: alkylamide or dialkylamide (-NR 1 R 2 (Here, R 1 and R 2 However, independently, it is a hydrocarbon group or hydrogen having 1 to 10 carbon atoms)), siloxo (-OSiR 1 R 2 R 3 (Here, R 1 , R 2 However, they are hydrocarbon groups that independently have 1 to 10 carbon atoms), silylamide (-N(SiR 1 3)(R 2 )(Here, R 1 and R 2 However, independently, it is a hydrocarbon group having 1 to 10 carbon atoms), disilylamide (-N(SiR 1 3)(SiR 2 3) (Here, R 1 and R 2However, these are independently hydrocarbon groups having 1 to 10 carbon atoms), alkoxo and aryloxo (-OR (where R is an alkyl or aryl group having 1 to 10 carbon atoms)), azide (-N3), alkynide (-C≡CR (where R is a hydrocarbon group having 1 to 9 carbon atoms)), amidate (-NR 1 (COR 2 )(Here, R 1 and R 2 However, independently, it is a hydrocarbon group or hydrogen having 1 to 7 carbon atoms), amidinate (-NR 1 C(NR 2 )R 3 )(Here, R 1 and R 2 However, independently, it is a hydrocarbon group or hydrogen having 1 to 8 carbon atoms), imide (-N(COR 1 )(COR 2 )(Here, R 1 and R 2 However, independently, a hydrocarbon group or hydrogen having 1 to 8 carbon atoms)) or a fluorinated analog thereof.

[0044] Metals in inorganic or organometallic materials can significantly influence radiation absorption. Tin exhibits strong absorption of extreme ultraviolet light at 13.5 nm. When combined with alkyl ligands, the metal exhibits even stronger absorption of ultraviolet light at a wavelength of 193 nm. Tin also provides good absorption under electron beam irradiation. The absorbed energy is modulated by metal-organic interactions, resulting in the breaking of metal-ligand bonds, allowing for desired control over the material's performance. Nevertheless, it is possible to introduce other metal compositions to further influence the overall absorption and resist properties. As mentioned earlier, other non-tin metals are generally MX n It is introduced as follows, where X is a ligand that has a hydrolyzable bond to the metal.

[0045] By using precursor compounds containing ligands with hydrolyzable bonds to metals, the preparation of precursor solutions can be simplified because in-situ hydrolysis eliminates many of the synthesis and isolation steps required to obtain a given hydrolysis reaction product. In particular, avoiding solution-based steps avoids potentially difficult process steps, as solution-phase hydrolysis and the subsequent condensation and isolation of organotin oxide hydroxide hydrolysates can involve large changes in solubility during the reaction. As long as the precursor composition contains components that are hydrolyzable separately, these particular components can be obtained using solution-based hydrolysis, for example, using a base-catalyzed aqueous solution as described in application 839. Components containing ligands with hydrolyzable bonds to metals can generally be purchased or synthesized from suitable starting materials, such as tin halide compositions or tetrakis(dialkylamide)tin compositions (as shown in the examples).

[0046] Formation of precursor solution and coating performance A series of precursor solutions can be formulated based on the compositions described in the previous section. These precursor compositions generally share the common feature of containing a metal-ligand bond that is somewhat sensitive to hydrolysis. For precursor compounds with sufficient vapor pressure, their hydrolysis can alternatively be carried out in situ during coating or as part of a vapor-phase deposition process. Precursor solutions for solution deposition generally contain a tin cation and optionally one or more non-tin metal cations in an organic solvent.

[0047] By selecting the concentration of ligand-stabilized metal cations in the solution, it is possible to obtain solution performance suitable for specific solution deposition approaches, such as spin coating, slot coating, dip coating, spray coating, aerosol coating, or printing, and to design the solution so that the solvent is removed at least partially, and a coating composition consisting of tin oxide-based inorganic solids is formed by irradiation and / or heat treatment, plasma exposure, or similar processing methods.

[0048] When using alkyl-stabilizing ligands and organic solvent-based precursor solutions, the progression to the oxide can be controlled as part of a procedure in which the solution is first processed into a coating material, and then the organic ligands are hydrolyzed and condensed using ambient water vapor during coating, and / or hydrolyzed and condensed after coating, to process the solution into the final metal oxide composition. As described herein, the effective processing of the solution into a radiation resist composition can be significantly controlled by using alkyl ligands, particularly branched alkyl ligands, and / or combinations of alkyl ligands in stoichiometric amounts relative to the metal. Processing with alcohol-based solvents involves partially or completely substituting the alcohol with an alkoxy ligand in the initial ligand with a hydrolyzable bond to the metal, but such substitution does not need to significantly alter the downstream processing.

[0049] The concentration of the precursor solution can be conveniently determined based on the molar concentration of tin ions, and the concentrations of various other metals can also be correspondingly determined from the molar fractions of those metals relative to tin. Generally, the precursor solution contains about 0.005 M to about 1.4 M of tin cations, about 0.02 M to about 1.2 M in further embodiments, and about 0.1 M to about 1.0 M in even further embodiments. The non-tin metals in the precursor solution can, in total, generally range from about 0.025 mol% to about 10 mol% of the total metal ions, and in further embodiments, about 10 mol% to about 50 mol% of the total metal ions. As is well known to those skilled in the art, further ranges of tin cations within the ranges expressed above are also conceivable and are included in the disclosure of the present invention.

[0050] Generally, the desired hydrolyzate compound can be dissolved in organic solvents, such as alcohols, aromatic and aliphatic hydrocarbons, esters, or combinations thereof. Particularly preferred solvents include, for example, aromatic compounds (e.g., xylene, toluene), ethers (anisole, tetrahydrofuran), esters (propylene glycol monomethyl ether acetate, ethyl acetate, ethyl lactate), alcohols (e.g., 4-methyl-2-propanol, 1-butanol, methanol, isopropyl alcohol, 1-propanol), ketones (e.g., methyl ethyl ketone), and mixtures thereof. Generally, the selection of organic solvents may be influenced by solubility parameters, volatility, flammability, toxicity, viscosity, and the possibility of chemical interactions with other processing materials. After dissolving and combining the components of the solution, the properties of the chemical species may be altered as a result of partial in-situ hydrolysis, hydration, and / or condensation. Where the composition of a solution is referenced herein, the reference values ​​refer to the components as they are added to the solution, because complex formulations involve sorbolisis and ligand metathesis, or generate polynuclear metal species in solution, making them difficult to characterize. For certain applications, it is desirable that the organic solvent has a flash point of about 10°C or higher, in further embodiments about 20°C or higher, and in further embodiments about 25°C or higher, and a vapor pressure of about 10 kPa or less at 20°C, in some embodiments about 8 kPa or less, and in further embodiments about 6 kPa or less. As is well known to those skilled in the art, further ranges of flash point and vapor pressure within the ranges specified above are also conceivable and are included in the disclosure of the present invention.

[0051] The concentration of chemical species in the precursor solution can be selected to obtain the desired physical properties of the solution. In particular, lower overall concentrations can impart desirable properties to solutions for certain coating approaches, such as spin coating (which allows for the achievement of thinner coatings using reasonable coating parameters). Thinner coatings are desirable to achieve ultrafine pattern formation and reduce material costs. Generally, the selected coating approach can be optimized by selecting the concentration. Coating performance will be discussed in more detail below.

[0052] Generally, the precursor solution can be thoroughly mixed using a suitable mixing apparatus appropriate to the volume of material to be formed. Contaminants or other components that do not dissolve properly can be removed using a suitable filtration. In some embodiments, it is preferable to form separate solutions, which can be combined to form a precursor solution from the combination. In particular, separate solutions containing one or more of the compounds shown earlier in formula (1) can be formed. Generally, these separate solutions or the combined solutions are thoroughly mixed. The solution thus obtained can be considered a stabilized metal cation solution.

[0053] The stability of these precursor solutions can be evaluated by utilizing the changes from the initial solution. In particular, a solution loses stability if phase separation occurs, resulting in the generation of a large amount of sol particles, or if the solution loses its ability to perform the desired pattern formation. Based on the improved stabilization approaches described herein, these solutions can remain stable for at least about one week, at least about two weeks in further embodiments, and at least about four weeks in other embodiments, without additional mixing. As is well known to those skilled in the art, additional ranges of stabilization times can also be considered and are also included in the disclosure of this invention. Suitable solutions can generally be formulated to have a sufficient stabilization time so that they have a suitable shelf life and can be commercially distributed.

[0054] As described herein, processing approaches and methods for reducing metal contamination have been developed. Thus, it is possible to formulate precursor solutions to contain only extremely low levels of metals other than tin. Generally, the concentrations of all foreign metals can be as low as approximately 1 ppm or less by weight, approximately 200 ppb or less by weight in further embodiments, approximately 50 ppb or less in subsequent embodiments, and approximately 10 ppb or less in other embodiments. In some embodiments, it is desirable to add other metallic elements to affect the processing, and generally, they are recognized at a level of at least approximately 1 weight percent, and in some embodiments at least approximately 2 weight percent, and thus can be distinguished from the contaminating metals where appropriate. Metal contaminants to be reduced include, in particular, alkali metals and alkaline earth metals, Au, Ag, Cu, Fe, Pd, Pt, Co, Mn, and Ni. As is well known to those skilled in the art, further ranges of metal levels within the ranges specified above are also conceivable and are included in the disclosure of this invention.

[0055] Conventional efforts to produce precursor solutions and coatings with low metal contamination are described in the '839 patent application. Using steam water for hydrolysis yields a hydrolytic reagent that is substantially free of metal contaminants, which can efficiently facilitate the production of low-contamination, patternable coatings based on low-contamination tin compositions. Suitable starting materials with low metal contamination can be obtained commercially or by purification.

[0056] Coating process and hydrolysis in situ The coating material can be formed by deposition, and then the precursor solution is processed on a selected substrate. When using the precursor solutions described herein, some hydrolysis and condensation generally occur during coating, but may be completed by subsequent steps, such as heating in air, or further post-coating may be carried out. The substrate generally provides a surface on which the coating material can be deposited, and the substrate may consist of multiple layers, where the surface is the uppermost layer. In some embodiments, the substrate surface may be treated to provide a surface for adhesion of the coating material. Furthermore, the surface may be cleaned and / or appropriately smoothed. Suitable substrate surfaces can include any reasonable material. Some substrates of particular interest 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 on the entire surface and / or in layers of the substrate. Wafers, such as relatively thin cylindrical structures, are convenient, but structures of any reasonable shape can also be used. Substrates having a polymer layer on a polymer substrate or a non-polymeric structure may be desirable in certain applications because they are low-cost and flexible, and suitable polymers can be selected because they can be used at relatively low processing temperatures for processing the patternable materials described herein. Suitable polymers include, for example, polycarbonates, polyimides, polyesters, polyalkenes, copolymers thereof, and mixtures thereof. Generally, it is desirable for the substrate to have a flat surface, especially in high-resolution applications. However, in certain embodiments, the substrate may have substantially topography, in which case the resist coating is used for the purpose of filling and planarizing features for specific patterning applications.Alternatively, using the vapor deposition method described herein, existing topography and features can be conformally coated with organotin oxide hydroxide photoresist for specific patterning applications.

[0057] In general, in addition to the vapor deposition process disclosed herein, various suitable solution coating processes can be used to deliver the precursor solution to the substrate. Suitable coating approaches include, for example, spin coating, spray coating, dip coating, knife-edge coating, printing approaches such as inkjet printing, and screen printing. In some of these coating approaches, a pattern of the coating material is formed during the coating process, but the resolution obtainable by printing methods and the like at present is significantly lower than that obtainable based on radiation-based pattern formation as described herein.

[0058] When pattern formation is performed using radiation, spin coating can be a desirable approach for relatively homogeneous coverage of the substrate, although edge effects may occur. In some embodiments, the wafer is rotated at a speed of about 500 rpm to about 10,000 rpm, in further embodiments about 1,000 rpm to about 7,500 rpm, and in even later embodiments about 2,000 rpm to about 6,000 rpm. By adjusting the spinning speed, the desired coating thickness can be obtained. Spin coating can be carried out over a period of about 5 seconds to about 5 minutes, in further embodiments about 15 seconds to about 2 minutes. Initially, a low-speed spin, for example, 50 rpm to 250 rpm, can be used to perform initial bulk spreading of the composition across the entire substrate. All edge beads can be removed by performing back-side rinsing, edge bead removal steps, etc., using water or other suitable solvents. As is well known to those skilled in the art, further ranges of spin coating parameters within the ranges expressed above are also conceivable and are included in the disclosure of the present invention.

[0059] The thickness of the coating can generally be a function of the concentration and viscosity of the precursor solution and the spin velocity of the spin coating. In other coating processes as well, the thickness can generally be adjusted by selecting coating parameters. In some embodiments, it is desirable to use a thin coating to facilitate the formation of fine, high-resolution features in the subsequent patterning process. For example, the dried coating material can have an average thickness of: about 10 microns or less, about 1 micron or less in other embodiments, about 250 nanometers (nm) or less in further embodiments, about 1 nanometer (nm) to about 50 nm in even later embodiments, about 2 nm to about 40 nm in other embodiments, and about 3 nm to about 25 nm in some embodiments. As is well known to those skilled in the art, further ranges of thickness within the ranges expressed above are also conceivable and are included in the disclosure of this invention. The thickness can be evaluated using non-contact methods, X-ray reflectivity and / or ellipsometry based on the optical properties of the film. Generally, the coating is relatively homogeneous, which facilitates processing. In some embodiments, the variation in coating thickness is less than or equal to ±50% of the average coating thickness, in further embodiments less than or equal to ±40%, and in even later embodiments less than or equal to ±25% of the average coating thickness. For example, in some embodiments such as highly homogeneous coating on a larger substrate, the evaluation of coating homogeneity is often performed by excluding 1 centimeter from the edge, i.e., the homogeneity of the coating is not evaluated in the portion of the coating within 1 centimeter from the edge. As is well known to those skilled in the art, further ranges within the ranges expressed above are also conceivable and are included in the disclosure of the present invention.

[0060] The coating process itself involves the evaporation of some of the solvent because many coating processes create droplets or other shapes of the coating material to obtain a large surface area and / or move the solution to promote evaporation. As the solvent is lost, the concentration of chemical species in the material increases, and the viscosity of the coating material tends to increase. The purpose of the coating process is to remove as much of the solvent as possible to stabilize the coating material for the next processing step. Reactive chemical species condense during coating or subsequent heating, forming hydrolyzed coating materials.

[0061] Generally, coating materials can be exposed to atmospheric moisture before radiation exposure and optionally heated to hydrolyze the hydrolyzable bonds to the metal in their precursor composition and / or further expel the solvent, thereby promoting the densification of the coating material. After in-situ hydrolysis, the coating material can generally form a polymeric metal oxo-hydroxo network (in which the metal has several ligands) based on the bonding of oxo-hydroxo ligands to the metal, or a molecular solid consisting of polynuclear metal oxo / hydroxo chemical species containing alkyl ligands.

[0062] The hydrolysis / solvent removal process may or may not be quantitatively controlled for the precise stoichiometry of the heated coating material and / or for a specific amount of solvent remaining in the coating material. Furthermore, the formulas and compositions expressed 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 thus obtained coating material is performed to enable the selection of processing conditions effective for the patterning process. While heating is not necessary for the successful application of the process, it is desirable to heat the coated substrate to increase the processing speed and / or improve the reproducibility of the process and / or facilitate the evaporation of reaction products from hydrolysis, such as amines and / or alcohols. In embodiments in which heat is applied for the purpose of removing the solvent, the coating material may be heated to a temperature of about 45°C to about 250°C, and in further embodiments to about 55°C to about 225°C. Heating for solvent removal can generally be carried out for at least about 0.1 minutes, in further embodiments for about 0.5 minutes to about 30 minutes, and in even further embodiments for about 0.75 minutes to about 10 minutes. As is well known to those skilled in the art, further ranges of heating temperatures and times within the ranges expressed above are also conceivable and are included in the disclosure of the present invention. As a result of the heat treatment, hydrolysis, and densification of the coating material, the coating material can exhibit an increase in refractive index and radiation absorption without a significant decrease in contrast.

[0063] Gas-phase based coating formation For the development of vapor-phase deposition of radiation-patternable organotin oxide hydroxide coatings, development of precursor compounds containing both R- groups with substantially non-hydrolyzable bonds to Sn and X ligands with hydrolyzable bonds to Sn has been developed. In particular, many R- groups, such as those listed in Table 1, have been developed. n Sn (4-n)Because the compounds have relatively high vapor pressure and reactivity, vapor deposition (VPD) can be used to deposit thin-film photoresists of organotin oxide hydroxides. By introducing hydrolyzable precursors in the gas phase into a sealed reactor from the ambient atmosphere, hydrolysis can be carried out as part of the deposition process, i.e., chemical vapor deposition. Available VPD methods include chemical vapor deposition (CVD), atomic layer deposition (ALD), and their modifications, many of which have been used for a long time to deposit inorganic metal oxide and nitride films using metal alkylamides, alkoxides, and halide precursors [1-4], and also include SnO2 from Sn(NMe2)4 [5]. To carry out VPD, one or more metal-containing precursors are generally reacted with one or more small-molecule vapor-phase reagents, such as H2O, H2O2, O3, O2, or CH3OH, which serve as oxygen and hydrogen sources to produce oxides and oxide hydroxides. If necessary, a physical vapor deposition approach can also be implemented, in which a precursor composition containing ligands with hydrolyzable bonds to Sn is deposited from the gas phase, and these bonds are then hydrolyzed after the coating is formed. In the case of vapor deposition, it is generally more efficient to induce hydrolysis / oxidation during deposition.

[0064] [Table 1]

[0065] In the CVD method, two or more reaction gases are typically mixed in a chamber near the substrate surface. Therefore, sufficient stability is designed to ensure reaction conditions that can control undesirable gas-phase reactions and nucleation. The ALD precursor, introduced separately and sequentially into the reaction chamber, typically reacts with chemiadsorbed co-precursors or decomposition reaction products that saturate the substrate surface. n Sn (4-n)Desirable characteristics of the precursor include, for example, sufficient volatility for gas-phase transport into the system, thermal stability to prevent premature decomposition, and appropriate reactivity with co-precursors to produce the target reaction product under given process conditions. The reaction process can be controlled by selecting the pressure and temperature within the reaction chamber.

[0066] Generally, precursors with relatively low vapor pressure can be introduced using vapor, aerosol flow, and / or by directly injecting liquid into the evaporation chamber. A flash evaporator can be used to introduce a controlled amount of precursor vapor into the reaction chamber and regulate the reaction process in the chamber accordingly. It is also possible to introduce a secondary reactant into the chamber from another inlet to promote hydrolysis / oxidation. For this use, commercially available CVD equipment may be modified, or specific equipment may be used. To facilitate deposition, the substrate may be heated or cooled depending on the properties of the precursor. For example, an inert gas such as N2 or Ar may be used in appropriate amounts as a carrier gas, purge gas, or pressure regulating gas in either a sequential or continuous inflow method.

[0067] A series of R2224 n Sn (4-n)Compounds (where n=0, 1, or 2) or combinations thereof are also suitable for vapor deposition of organotin oxide hydroxide photoresists having desirable properties. Useful X ligands include alkylamides and dialkylamides, chloro, alkoxo, or alkynides, siloxo, silylamides, disilylamides, aryloxo, azides, amidates, amidinates, or their fluorinated analogs, which are combined with hydrocarbyl R groups, including both linear and branched alkyl, cycloalkyl, aryl, alkenyl, alkynylbenzyl, and their fluorinated derivatives. Suitable precursors include, for example, the following: (CH3)3CSn(NMe2)3, (CH3)2CHSn(NMe2)3, (CH3)2(CH3CH2)CSn(NMe2)3, (CH2)2CHSn(NMe2)3, CH3Sn(NMe2)3, (CH2)3CHSn(NMe2)3, (CH2)4CHSn(NMe2)3, (C6H5)CH2Sn(NMe2)3, (C6H5)(CH3)CHSn(NMe2)3, (C6H5)(CH3)CHSn(NMe2)3, (CH3)2(CN)CSn(NMe2)3, (CH3)(CN)CHSn(NMe2)3, or (CH3)3CSn(O t Bu)3, (CH3)2CHSn(O t Bu)3, (CH3)2(CH3CH2)CSn(O t Bu)3, (CH2)2CHSn(O t Bu)3, CH3Sn(O t Bu)3, (CH2)3CHSn(O t Bu)3, (CH2)4CHSn(O t Bu)3, (C6H5)CH2Sn(O) t Bu)3, (C6H5)(CH3)CHSn(O t Bu)3, (C6H5)(CH3)CHSn(O t Bu)3, (CH3)2(CN)CSn(O t Bu)3, (CH3)(CN)CHSn(O t Bu)3, and others known to those skilled in the art. Furthermore, one or more gas phase precursor compounds where = 0, for example, Sn(NMe2)4 or Sn(O tBu)4 may be reacted sequentially or simultaneously with organotin-containing precursors to change the R:Sn ratio in the film, thereby achieving the desired pattern formation characteristics.

[0068] Therefore, it is possible to directly deposit hydrolyzable compounds by gas-phase hydrolysis to form the corresponding alkyltin oxide hydroxide coating, which can then be appropriately patterned. Advantages of gas-phase deposition include, for example, a reduction in defect density of the resist film, improved uniformity of thickness and composition, and conformal coating and sidewall coating of the substrate topography.

[0069] General formula RSnO (3 / 2-x / 2) (OH) xIn some embodiments, a vapor deposition method for directly depositing an organotin oxide hydroxide using (0 < x < 3) may include an inert gas source connected to a separate heated bubbler vessel. The first vessel contains a liquid alkyltris(dialkylamide)tin compound with a vapor pressure sufficient to generate a partial pressure suitable for transport in an inert carrier gas. The second vessel contains liquid water or a water / alcohol mixture. By adjusting the temperature of the vessels, the flow rate of the inert gas, and the total pressure of the system, gaseous RSn(NR’2)3 and H2O are independently transported to a chamber evacuated to about 0.1 Torr, more typically about 0.01 Torr to about 25 Torr, to an ambient pressure with CVD pressure > 25 Torr. The precursors are mixed and reacted therein to deposit an organotin oxide hydroxide on a substrate. The substrate and / or the chamber and / or the vapor may be heated to promote reaction and deposition on the substrate surface. In some embodiments, it is desirable to have a reaction temperature below about 200 °C to limit the dealkylation reaction of the tin compound and / or to prevent excessive dehydration and condensation of the oxide hydroxide. When such an oxide hydroxide is formed, there is a possibility of a decrease in the contrast of the dissolution rate of the photoresist between the exposed and unexposed areas. In various embodiments, the gas, chamber walls, and / or the substrate may be heated to a temperature generally of about 40 °C to about 175 °C, and in further embodiments about 50 °C to about 160 °C. As is well recognized by those skilled in the art, further ranges of pressure and temperature within the ranges specified above are also contemplated and are included in the disclosure of the present invention. Similarly, in related processes, appropriate intervals and periods of pulses of water vapor, inert gas, and RSn(NR’2)3 may be varied to allow for a surface-limited adsorption and reaction mode typical of the ALD method.

[0070] Pattern formation and properties of the patterned structure After hydrolysis, condensation, and drying, the coating material can be finely patterned using radiation. As previously mentioned, the composition of the precursor solution and the corresponding coating material therefrom can be designed to adequately absorb the desired form of radiation. The absorption of radiation can yield energy that breaks the bonds between the metal and the alkyl ligands, so that at least some of the alkyl ligands are no longer utilized for stabilizing the material. The products of the radiolysis reaction, including the alkyl ligands or their fragments, may or may not diffuse out of the film, depending on the process variables and the identification of such reaction products. Upon absorption of a sufficient amount of radiation, the exposed coating material condenses, i.e., forms a higher-grade metal oxo-hydroxo network, which may contain additional water absorbed from the ambient atmosphere. Radiation can generally be delivered according to a selected pattern. The pattern of radiation is converted into a corresponding pattern, or latent image, in the coating material between the irradiated and unirradiated regions. The irradiated areas contain chemically altered coating material, while the unirradiated areas generally contain the original, unaltered coating material. As will be explained below, developing the coating material to remove the unirradiated coating material, or alternatively, selectively remove the irradiated coating material, can create extremely smooth edges.

[0071] Radiation can generally be directly shone onto a coated substrate through a mask, or the radiation beam can be scanned over the substrate in an adjustable manner. Common examples of radiation 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 generally depends on the wavelength of the radiation; generally, shorter wavelengths of radiation can be used to obtain higher resolution patterns. Therefore, it is preferable to use ultraviolet light, X-rays, or electron beams, especially to obtain high-resolution patterns.

[0072] According to the international standard ISO 21348 (2007), which is incorporated herein by reference, ultraviolet light refers to wavelengths between 100 nm and less than 400 nm. A krypton fluoride laser can be used as a light source for 248 nm ultraviolet light. The ultraviolet range can also be further subdivided in several ways in accepted standards; for example, 10 nm to less than 121 nm is extreme ultraviolet (EUV), and 122 nm to less than 200 nm is far ultraviolet (FUV). The 193 nm line from an argon fluoride laser can be used as a radiation source for FUV. 13.5 nm EUV light has been used for lithography, but this light is generated using a Xe or Sn plasma source excited with a high-energy laser or discharge pulse. Soft X-rays can be defined as 0.1 nm to less than 10 nm.

[0073] The amount of electromagnetic irradiation can be characterized by fluence or dose, which is defined by the integrated radiant flux during the exposure time. A suitable radiant fluence is approximately 1 mJ / cm². 2 ~Approx. 150mJ / cm 2 In further embodiments, approximately 2 mJ / cm² 2 ~Approx. 100mJ / cm 2 In further embodiments, approximately 3 mJ / cm² 2 ~about 50mJ / cm 2This is possible. As is well known to those skilled in the art, further ranges of radiant fluence within the ranges expressed above are also conceivable and are included in the disclosure of this invention.

[0074] When using electron beam lithography, the electron beam generally induces secondary electrons, which generally modify the irradiated material. Resolution is at least partially a function of the range of secondary electrons in the material, and generally, a narrower range of secondary electrons is considered to result in higher resolution. Based on the high resolution achievable with electron beam lithography using the inorganic coating materials described herein, there are limits to the range of secondary electrons in the inorganic material. The electron beam can be characterized by its energy, with preferred energies ranging from about 5 V to about 200 kV (kilovolts), and in further embodiments, from about 7.5 V to about 100 kV. The proximity-corrected beam dose at 30 kV is about 0.1 microcoulombs / cm² to about 5 millicoulombs / cm² (mC / cm²). 2 In further embodiments, approximately 0.5 μC / cm² 2 ~about 1mC / cm 2 In other embodiments, approximately 1 μC / cm² 2 ~about 100μC / cm 2 The range can be as follows. Those skilled in the art can calculate doses corresponding to other beam energies based on the teachings herein, or further ranges of electron beam properties within the ranges expressed above can be considered and are also included in the disclosure of this invention.

[0075] Based on the design of the coating material, a significant contrast in material properties can be achieved between the irradiated area (where the coating material is condensed) and the unirradiated area (where the organic ligands are substantially unchanged). While the contrast at a given dose can be improved by post-irradiation heat treatment, in some embodiments, satisfactory results have been found without post-irradiation heat treatment. Post-exposure heat treatment anneals the irradiated coating material and increases its condensation, but the unirradiated area of ​​the coating material does not appear to undergo significant condensation based on thermal fracture of organic ligand-metal bonds. In embodiments using post-irradiation heat treatment, the heat treatment can be carried out at temperatures of approximately 45°C to approximately 250°C, in further embodiments approximately 50°C to approximately 190°C, and in even further embodiments approximately 60°C to approximately 175°C. Post-exposure heating can generally be carried out for at least approximately 0.1 minutes, in further embodiments approximately 0.5 minutes to approximately 30 minutes, and in even further embodiments approximately 0.75 minutes to approximately 10 minutes. As is well known to those skilled in the art, further ranges of post-irradiation heating temperatures and times within the ranges specified above are also conceivable and are included in the disclosure of the present invention. The high contrast performance in this material facilitates the formation of high-resolution lines with smooth edges in its patterns, which will be discussed in the following section.

[0076] After exposure with radiation, the coating material is patterned with irradiated and unirradiated regions. Referring to Figures 1 and 2, the patterned structure 100 includes a substrate 102, a thin film 103, and a patterned coating material 104. The patterned coating material 104 includes regions 110, 112, 114, and 116 of the irradiated coating material and uncondensed regions 118, 120, and 122 of the unirradiated coating material. The pattern formed by the condensed regions 110, 112, 114, and 116 and the uncondensed regions 118, 120, and 122 represents a latent image created in the coating material, the development of which will be discussed in the next section.

[0077] Developed and patterned structures Image development involves contacting a patterned coating material containing a latent image with a developer composition to either remove the unirradiated coating material to form a negative image, or remove the irradiated coating to form a positive image. Using the resist materials described herein, it is generally possible to perform effective negative or positive pattern formation with the desired resolution using a suitable developer solution, generally based on the same coating. In particular, if the irradiated area is at least partially condensed and its metal oxide properties are enhanced, the irradiated material becomes resistant to dissolution by organic solvents, while the unirradiated composition still retains its solubility in organic solvents. When referring to a condensed coating material, it is suggested that at least partial condensation has occurred in the sense that the oxide properties of the material are higher compared to the original material. On the other hand, the unirradiated material has low solubility in weakly basic or weakly acidic aqueous solutions due to its hydrophobicity, and therefore it is possible to remove the irradiated material while retaining the unirradiated material in positive pattern formation using an aqueous base.

[0078] A coating composition containing organic-stabilizing ligands produces an inherently hydrophobic material. Irradiation that breaks at least some of the organometallic bonds converts the material into a less hydrophobic, i.e., more hydrophilic, material. This change in properties results in a significant contrast between the irradiated and unirradiated coatings, allowing both positive and negative pattern formation to be achieved using the same resist composition. In particular, the irradiated coating material condenses to some extent into a greater-than-average metal oxide composition; however, the degree of condensation is generally moderate unless excessive heat is applied, and therefore the irradiated material can be developed relatively easily using a suitable developer.

[0079] Referring to Figures 3 and 4 for negative image formation, the latent images of the structures shown in Figures 1 and 2 are developed by contact with the developer, forming the patterned structure 130. After the image is developed, the substrate 102 is exposed to the upper surface through apertures 132, 134, and 135. Apertures 132, 134, and 135 are located at the positions of the unconjugated regions 118, 120, and 122, respectively. Referring to Figures 5 and 6 for positive image formation, the latent images of the structures shown in Figures 1 and 2 are developed, forming the patterned structure 140. The patterned structure 140 has a conjugate image with the patterned structure 130. The patterned structure 140 is the substrate 102 exposed at the positions of the irradiated regions 110, 112, 114, and 116, which is developed to form apertures 142, 144, 146, and 148.

[0080] In the case of negative-toned image formation, the developer may be an organic solvent, such as the solvent used to form the precursor solution. Generally, the following factors influence the selection of the developer: solubility parameters for the coating material, both when irradiated and when not irradiated, as well as the developer's volatility, flammability, toxicity, viscosity, and potential for chemical interactions with other process materials. Particularly suitable developers include, for example, aromatic compounds (e.g., benzene, xylene, toluene), esters (e.g., propylene glycol monomethyl acetate, ethyl acetate, ethyl lactate, n-butyl acetate, butyrolactone), alcohols (e.g., 4-methyl-2-pentanol, 1-butanol, isopropanol, 1-propanol, methanol), ketones (e.g., methyl ethyl ketone, acetone, cyclohexanone, 2-heptanone, 2-octanone), and ethers (e.g., tetrahydrofuran, dioxane, anisole). Development can be carried out for approximately 5 seconds to approximately 30 minutes, in a further embodiment for approximately 8 seconds to approximately 15 minutes, and in a subsequent embodiment for approximately 10 seconds to approximately 10 minutes. As is well known to those skilled in the art, further ranges within the ranges expressed above are also conceivable and are included in the disclosure of the present invention.

[0081] For positive-tone image formation, the developer can generally be an aqueous acid or base. In some embodiments, a sharp image can be obtained using an aqueous base. To reduce contamination from the developer, it is desirable to use a developer that does not contain metal atoms. Therefore, quaternary ammonium hydroxide compositions, such as tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, or combinations thereof, are preferred as developers. In general, a quaternary ammonium hydroxide of particular interest can be represented by the formula R4NOH, where R = methyl group, ethyl group, propyl group, butyl group, or combinations thereof. The coating materials described herein can generally be developed using the same developers currently commonly used for polymer resists, particularly tetramethylammonium hydroxide (TMAH). TMAH is available commercially at 2.38 weight percent, and this concentration can be used for the processing described herein. Furthermore, mixed quaternary tetraalkylammonium hydroxides can also be used. The developer may generally contain tetraalkylammonium hydroxide or similar quaternary ammonium hydroxide in amounts of about 0.5 to about 30 weight percent, in further embodiments about 1 to about 25 weight percent, and in other embodiments about 1.25 to about 20 weight percent. As is well known to those skilled in the art, further ranges of developer concentrations within the ranges expressed above are also conceivable and are included in the disclosure of the present invention.

[0082] In addition to the main developer composition, the developer may include additional compositions to facilitate the development process. Suitable additives include, for example, soluble salts of cations selected from the group consisting of ammonium, d-block metal cations (such as hafnium, zirconium, and lanthanum), f-block metal cations (such as cerium and lutetium), p-block metal cations (such as aluminum and tin), alkali metals (such as lithium, sodium, and potassium), and combinations thereof, with anions selected from the group consisting of fluorides, chlorides, bromides, iodides, nitrates, sulfates, phosphates, silicates, borates, peroxides, butoxides, formates, oxalates, ethylenediaminetetraacetic acid (EDTA), tungstates, molybdates, and combinations thereof. Other possible useful additives include, for example, chelating agents in molecular form, such as polyamines, alcoholamines, amino acids, carboxylic acids, or combinations thereof. When 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. As is well known to those skilled in the art, further ranges of additive concentrations within the ranges specified above are also conceivable and are included in the disclosure of this invention. Additives can be selected to improve contrast, sensitivity, and line width roughness. Additives in the developer may also further prevent the formation and precipitation of metal oxide particles.

[0083] When using weaker developers, such as low-concentration aqueous developers, diluted organic developers, or compositions with slower coating development speeds, higher temperature development processes can be used to increase processing speed. With stronger developers, the speed can be reduced and / or the dynamics of development can be adjusted by lowering the temperature of the development process. Generally, the development temperature should be adjusted within a range appropriate to the volatility of the solvent. Furthermore, developers that dissolve the coating material near the developer-coating interface can be dispersed using ultrasound during development.

[0084] Developers can be applied to patterned coating materials using various rational approaches. For example, the developer can be sprayed onto the patterned coating material. Spin coating can also be used. In automated processing, the paddle method can be used, in which the developer is poured onto a certain form of coating material. If necessary, the development process can be completed using spin rinsing and / or drying. Suitable rinsing solutions include, for example, ultrapure water, methyl alcohol, ethyl alcohol, propyl alcohol, and combinations thereof for negative pattern formation, and ultrapure water for positive pattern formation. After the image has been developed, the coating material is arranged as a pattern on the substrate.

[0085] After the development process is complete, the coating material can be heat-treated to further condense, dehydrate, and densify the material, or to remove any remaining developer. This heat treatment may be particularly desirable in embodiments where the oxide coating material is incorporated into the final device, but it is also desirable to perform the heat treatment 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 pattern formation. In particular, baking of the patterned coating material can be performed under conditions where the patterned coating material exhibits a desired level of etch 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 even later embodiments about 200°C to about 400°C. Heating can be performed for at least about 1 minute, in other embodiments about 2 minutes to about 1 hour, and in further embodiments about 2.5 minutes to about 25 minutes. Heating is preferably performed in air, vacuum, or in an inert gas atmosphere, such as Ar or N2. As is well known to those skilled in the art, further ranges of temperatures and times for heat treatment within the ranges specified above are also conceivable and are included in the disclosure of this invention. Similarly, non-heat treatments, such as blanket UV exposure or exposure to an oxidizing plasma such as O2, may also be employed in the same process.

[0086] When using conventional organic resists, if the aspect ratio (height / width) of a structure becomes too large, the structure is prone to pattern collapse. Pattern collapse is due to the mechanical instability of high-aspect-ratio structures, for example, forces during the processing, such as surface tension, that distort the structural elements. With respect to potential strain forces, low-aspect-ratio structures are more stable. When using the patternable coating materials described herein, improved pattern formation is possible without requiring high-aspect-ratio patterned coating materials because they have high etch resistance and the ability to efficiently process structures using thinner layers of coating material. Therefore, extremely high-resolution features can be formed without using high-aspect-ratio features in the patterned coating material.

[0087] The resulting structures can have extremely low line width roughness along with sharp edges. In particular, in addition to the ability to reduce line width roughness, the high contrast further enables the formation of small features and spaces between features, and provides the ability to form extremely well-resolved two-dimensional patterns (e.g., sharp corners). Thus, in some embodiments, adjacent linear segments of nearby structures can have an average pitch (half pitch) of about 60 nm or less (30 nm or less at half pitch), in some embodiments about 50 nm or less (25 nm or less at half pitch), and in further embodiments about 34 nm or less (17 nm or less at half pitch). The pitch can be evaluated from the design and confirmed using scanning electron microscopy (SEM), for example, top-down imaging. As used herein, “pitch” refers to the spatial period or center-to-center distance of repeating structural elements, and “half pitch” is half the pitch, as commonly used in the art. Feature dimensions of the pattern can also be described in relation to the average width of the features, which is generally evaluated from corners, etc. Furthermore, "feature" can refer to the gap between and / or to material elements. The average width can be about 25 nm or less in some embodiments, about 20 nm or less in further embodiments, and about 15 nm or less in even later embodiments. The average linewidth roughness can be about 5 nm or less, about 4.5 nm or less in some embodiments, and about 2.5 nm to about 4 nm or less in further embodiments. This is done by analyzing top-down SEM images and deriving a 3σ deviation from the average linewidth. The average includes high-frequency roughness and low-frequency roughness, i.e., short-correlation distance and long-correlation distance, respectively. The linewidth roughness of organic resists is mainly characterized by the long-correlation distance, whereas the organometallic coating material of the present invention exhibits a remarkably short-correlation distance. In the pattern transfer process, the short-correlation roughness can be smoothed out during the etching process to obtain a pattern of higher fidelity.As is well known to those skilled in the art, further ranges of pitch, average width, and line width roughness within the ranges specified above are also conceivable and are included in the disclosure of the present invention. Based on these processes, patterning can generally be adapted through a repeating patterning process for forming appropriately layered structures, such as transistors or other elements, to form various devices, such as electronic integrated circuits.

[0088] Wafer throughput is a substantial limiting factor in the implementation of EUV lithography in mass-production semiconductor manufacturing, directly related to the dose required to pattern a given feature. However, although chemical strategies exist to reduce imaging dose, a negative correlation between the imaging dose required to print the target feature and the homogeneity of the feature size (e.g., LWR) is commonly observed in EUV photoresists with feature size and pitch less than 50 nm, thereby limiting the availability of the final device and wafer yield. However, the precursors, precursor solutions, and photoresist films described herein have been found to circumvent this limitation and suppress the EUV imaging dose over a substantial dose range without accompanying increases in LWR. As will be detailed in the following examples, R is hydrolyzed in situ during the coating and baking process. n Sn (4-n) By using a precursor solution containing a blend of and SnX4, a dose reduction of over 30% is observed, while the LWR is equivalent to or lower, compared to a photoresist film derived from a mixture of pre-hydrolyzed organotin oxide hydroxide compounds (prepared according to the description in the '839 application), when processed under the same conditions.

[0089] Based on the improved process described in the following examples, the improved properties of the coating material can be appropriately characterized. For example, a substrate containing an inorganic semiconductor layer and a radiosensitive coating material on its surface can be patterned with EUV light at a wavelength of 13.5 nm in a 16 nm line pattern at a pitch of 32 nm. To evaluate the coating material, the dose required to achieve the limiting dimension of 16 nm can be evaluated using the achievable linewidth roughness (LWR). In the improved coating, this is approximately 8 mJ / cm². 2 ~about 25mJ / cm 2 Depending on the dose, it is possible to achieve a limit dimension of 16 nm with a linewidth roughness of approximately 4 nm or less. Using SuMMIT analysis software (EUV Technology Corporation), the resist limit dimension (CD) and linewidth-roughness (LWR) were extracted from SEM images.

[0090] In further embodiments, improved pattern-forming performance can be expressed as a dose-to-gel value. Structures comprising a substrate and a radiosensitive coating containing alkyl metal oxide hydroxides exhibit a radiation dose of approximately 6.125 mJ / cm². 2 In further embodiments, the following is approximately 5.5 mJ / cm². 2 ~about 6mJ / cm 2 Dose versus gel value (D g ) can be present. The evaluation of dose versus gel value will be explained in the following examples.

[0091] References (incorporated herein by reference): 1)Maeng,WJ;Pak,SJ;Kim,HJVac.Sci.Tech B.2006,24,2276. 2) Rodriguez-Reyes, JCF; Teplyakov, AVJAppl.Phys.2008,104,084907. 3)Leskelae, M.; Ritala, M. Thin Solid Films 2002,409,138. 4) Leskelae, M.; Ritala, MJPhys.IV 1999, 9, Pr8-852. 5) Atagi, LM; Hoffman, DM; Liu, JR; Zheng, Z.; Chu, WK; Rubiano, RR; Springer, RW; Smith, DCChem. Mater. 1994, 6, 360. [Examples]

[0092] Example 1 - Preparation of precursor for in-situ hydrolysis This example aims to form an organotinamide compound suitable for in-situ hydrolysis to form an organotin oxide hydroxide coating.

[0093] The precursor tert-butyltris(diethylamide)tin, (tBuSn(NEt2)3, hereafter P-1) was synthesized according to the method described in Haenssgen, D.; Puff, H.; Beckerman, N., J. Organomet. Chem., 1985, 293, 191 (which is incorporated herein by reference). Tetrakis(diethylamide)tin and tBuLi reagents were purchased from Sigma-Aldrich and used without further purification. The reagents were reacted stoichiometrically in anhydrous hexane (Sigma-Aldrich) at -78°C. The precipitated lithium amide salt was removed by filtration, the reaction product was washed with hexane, and the solvent was stripped under vacuum. The crude reaction product was distilled under vacuum (approximately 0.3 torr, 95°C).

[0094] A solution was prepared by weighing 1.177 g (3.0 mmol) of P-1 into a 30 mL amber glass vial in a glove box filled with Ar, and then adding 15 mL of anhydrous 4-methyl-2-pentanol (dried on a 3A molecular sieve for 24 hours). The vial was capped and stirred. One part of this stock solution was diluted in 2.85 parts (vol) of anhydrous 4-methyl-2-pentanol and then coated.

[0095] Under an inert atmosphere, the precursor isopropyltris(dimethylamide)tin (iPrSn(NMe2)3, hereafter P-2) was synthesized and then dissolved in toluene to form a resist precursor solution. Under argon pressure, LiNMe2 (81.75 g, 1.6 mol, Sigma-Aldrich) and anhydrous hexane (700 mL, Sigma-Aldrich) were charged into a 1-L Schlenk-type round-bottom flask to form a slurry. A large stirring bar was added and the container was sealed. Under positive argon pressure, iPrSnCl3 (134.3 g, 0.5 mol, Gelest) was charged into a dropping funnel using a syringe and then attached to the reaction flask. The reaction flask was cooled to -78°C, and then iPrSnCl3 was added dropwise over 2 hours. The reaction solution was warmed to room temperature overnight while stirring. A solid by-product was generated in the reaction. After settling, the solid was filtered through an in-line cannula filter under positive argon pressure. Next, the solvent was removed under vacuum, and the residue was distilled under reduced pressure (50-52°C, 1.4 mmHg) to obtain a yellow liquid (110 g, yield 75%). 1 H and 119 The Sn NMR spectrum (in C6D6 solvent) was measured using a Bruker DPX-400 (400 MHz, BBO probe) spectrometer. 1 The H resonance (s, 2.82 ppm, -N(CH3)2; s, 1.26 ppm, -CH3; m, 1.60 ppm, -CH) is consistent with the spectrum predicted for iPrSn(NMe2)3 at -65.4 ppm. 119 The first-order resonance of Sn matches the main reaction product which has a solitary tin environment, and the chemical shift corresponds to the reported monoalkyltris(dialkylamide)tin compound.

[0096] A solution was prepared by weighing 0.662 g (2.25 mmol) of P-2 into a 30 mL amber glass vial in a glove box filled with Ar. Then, 15 mL by volume of anhydrous toluene (dried on a 3A molecular sieve for 24 hours) was added to prepare the stock solution (SOL-2). The vial was then capped and stirred. One part of this stock solution was diluted in three parts (by volume) of anhydrous toluene before being used for coating.

[0097] Example 2 - Patterning of photoresist coatings that undergo hydrolysis in situ This example demonstrates successful in-situ hydrolysis of a coating formed from the composition of Example 1, followed by EUV pattern formation.

[0098] A thin film was deposited on a silicon wafer (100 mm in diameter) that had its original oxide surface. The Si wafer was treated with hexamethyldisilazane (HMDS) vapor, and then an amide precursor was deposited. The P-1 solution in 4-methyl-2-pentanol was spin-coated onto the substrate in air at 1500 rpm, and then baked on a hot plate in air at 100°C for 2 minutes to evaporate any remaining solvent and volatile hydrolysis reaction products. The film thickness after coating and baking was measured by ellipsometry and was approximately 31 nm.

[0099] The coated substrate was exposed to extreme ultraviolet light (Lawrence Berkeley National Laboratory Micro Exposure Tool). A pattern of 17 nm lines with a 34 nm pitch was projected onto the wafer using 13.5 nm wavelength radiation, dipole illumination, and a numerical aperture of 0.3. The patterned resist and substrate were then subjected to post-exposure baking (PEB) on a hot plate in air at 170°C for 2 minutes. The exposed film was then immersed in 2-heptanone for 15 seconds, followed by washing with the same developer for another 15 seconds to form a negative image, i.e., to remove unexposed areas of the coating. After development, a final hot plate baking was performed in air at 150°C for 5 minutes. Figure 7 shows a 34 nm pitch EUV dose of 56 mJ / cm² prepared from P-1 cast from 4-methyl-2-pentanol. 2 The image shows an SEM image of a 16.7 nm resist line with a calculated LWR of 2.6 nm.

[0100] Using the same coating and baking conditions as above, a second film was cast from a solution of P-2 in toluene. A linear array of 50 circular pads, approximately 500 μm in diameter, was projected onto the wafer using EUV light. The exposure time of the pads was varied in stages, so that the EUV dose delivered to each pad ranged from 1.38 to 37.99 mJ·cm. -2 The thickness was then adjusted to progress exponentially in 7% increments. After the PEB, development, and final baking processes described above, the remaining thickness of the exposed pads was measured using a JAWoollam M-2000 Spectroscopic Ellipsometer. The thickness of each pad is plotted as a function of the delivered EUV dose in Figure 8. The resulting curve clearly represents the negative contrast produced by the exposure, with the remaining film thickness starting at approximately 0 and progressing to approximately 15.8 mJ·cm. -2 The maximum value in the delivery dose (dose versus gel value, D g It has reached ).

[0101] Example 3 - Evaluation of coatings hydrolyzed in situ In this embodiment, in the case of a precursor having a hydrolyzable bond to Sn, the in-situ hydrolysis approach provides evidence of substantially complete hydrolysis.

[0102] For comparative purposes, isopropyltin oxide hydroxide was prepared to form a radiosensitive coating. A solid hydrolysate of isopropyltin trichloride (iPrSnCl3, Gelest) was prepared. To this hydrolysate, 6.5 g (24 mmol) of isopropyltin trichloride was rapidly added to 150 mL of 0.5-M NaOH (aqueous solution) with vigorous stirring, and a precipitate immediately formed. The resulting mixture was stirred at room temperature for 1 hour and then filtered by suction through No. 1 filter paper (Whatman). The remaining solid was washed three times with 25 mL each of DI H2O and then dried under vacuum (approximately 5 torr) at room temperature for 12 hours. Elemental analysis of the dried powder (18.04% C, 3.76% H, 1.38% Cl; Microanalysis, Inc.; Wilmington, DE) showed that the chloride ions were substantially removed by the hydrolysis of isopropyltin trichloride, and the hydrolysate was almost identical to the empirical formula. i PrSnO (3 / 2-(x / 2)) (OH) x (Here, we show that x ≈ 1) (hereafter P-3). (Calculated values ​​for C3H8O2Sn: 18.50% C, 4.14% H, 0.00% Cl).

[0103] The dried powder is dissolved in 2-butanone to obtain a solid hydrolysate iPrSnO2 with a total Sn concentration of approximately 0.25 M. (3 / 2-(x / 2)) (OH) xSolutions were prepared. As previously described, a solution of P-2 in anhydrous 4-methyl-2-pentanol was prepared by adding 1.47 g (5.0 mmol) of P-2 to 10 mL of 4-methyl-2-pentanol. For each solution, a thin film was cast onto a 25 mm × 25 mm Si wafer by spin coating. The P-2 solution was coated at 2000 rpm, while the P-3 solution was coated at 1250 rpm. Following coating, each film was baked at 150 °C in air for 2 minutes. Although alcohol may react with P-2 to form an alkoxide ligand, in either case, even if an alkoxide ligand is formed, it is thought that it will be hydrolyzed to form an oxide-hydroxyl composition.

[0104] The Fourier transform infrared (FTIR) transmission spectra of these two films were measured using a Nicolet 6700 spectrometer with a clean substrate as the background. The representative spectra of the two films (Figure 8) were qualitatively very similar, suggesting that in both cases, substantially hydrolysis occurred, removing the amide / alkoxo ligand from the P-2 solution and depositing oxide hydroxides. In particular, at 2800–3000 cm⁻¹ -1 and 1100~1500cm -1 The fact that the regions are almost the same indicates that CH between the two membranes x This indicates that the compositions are similar and that virtually no CN chemical species exist.

[0105] Example 4 - Preparation of hydrolyzable precursors having tetrakis-dialkylamide or -tert-butoxosin compounds This example describes the formation of a mixed hydrolyzable precursor compound to enable the adjustment of the stoichiometry of radiosensitive ligands to metals in a radiosensitive coating.

[0106] Tert-butyltris(diethylamide)tin was synthesized according to the description in Example 1. Tetrakis(dimethylamide)tin (Sn(NMe2)4, FW=295.01) was purchased from Sigma-Aldrich and used without further purification.

[0107] Tin(IV)tert-butoxide, (Sn(O t Bu)4, FW=411.16, hereafter P-5) was prepared according to the method of Hampden-Smith et al., Canadian Journal of Chemistry, 1991, 69, 121 (which is incorporated herein by reference). Stannous chloride (152 g / 0.8 mol) and pentane (1 L) were added to a 3 L oven-dried round-bottom flask equipped with a magnetic stirrer and purged with nitrogen. Diethylamine (402 mL / 3.9 mol) and pentane (600 mL) were charged into a 1 L dropping funnel equipped with a nitrogen pressure inlet, then attached to the flask, and the flask was immersed in an ice bath. The amine solution was then added dropwise to maintain a gentle reflux. After the addition of the amine was complete, 2-methyl-2-propanol (290 g / 3.9 mol) in pentane (50 mL) was added to the dropping funnel and then added dropwise to the flask. After stirring for 18 hours, the slurry was transferred to a frit glass filter flask from which air had been removed, and the precipitated salt was removed. The solvent was removed under reduced pressure, and the target compound was distilled (boiling point = 60-62°C @ 1 torr). 1 1H NMR (C6D6): 1.45 ppm (s); 119 Sn NMR (C6D6): -371.4 ppm (s).

[0108] P-1 t Stock solution of BuSn(NEt2)3) (hereafter S-1), stock solution of P-4 (Sn(NMe2)4) (hereafter S-2), and P-5 (Sn(O tStock solutions of Bu)4) (hereafter S-3) were prepared by transferring the corresponding compounds via a cannula into separate flasks containing dehydrated 4-methyl-2-pentanol (dried on a 4A molecular sieve for 24 hours). Then, additional dehydrated 4-methyl-2-pentanol was added to dilute the solution to a final concentration of 0.25 M (Sn).

[0109] Further stock solution S-4 was prepared by immersing P-1 in an isopropanol / dry ice bath and then introducing 41 g of P-1 via cannula into a round-bottom flask containing 250 mL of methanol while stirring on a magnetic stirrer plate. t After transferring the aliquots of BuSn(NEt2)3, the flask containing the mixture was removed from the ice bath and allowed to stand at room temperature. Next, a rotary evaporator was attached, and the flask containing the mixture was heated to 50°C in a water bath. The solvent was stripped under reduced pressure (10 mtorr) to substantially complete evaporation of the solvent, yielding a viscous yellow oily substance. Finally, this yellow oily substance was dissolved in 1.0 L of 4-methyl-2-pentanol. The resulting solution was measured to have a molar concentration of 0.097 M [Sn] based on the remaining mass of the solution. The solvent was then evaporated, and the remaining solids were thermally decomposed to obtain SnO2.

[0110] Precursor coating solutions CS-a, CS-b, and CS-c were prepared by mixing stock solution S-1 with S-2 in volume ratios of 0.5:1 and 9:1, respectively, to obtain total Sn concentrations of 0(a), 10(b), and 20(c) mol% from Sn(NMe2)4 in the mixture. These solutions were then further diluted with 4-methyl-2-pentanol to 0.070 M (total Sn) before spin coating. For example, to prepare 200 mL of CS-b, 5.6 mL of the stock solution prepared from Sn(NMe2)4(S-2) was used. tThe precursor coating solution was added to 50.4 mL of a solution prepared from BuSn(NEt2)3(S-1), mixed vigorously, and then diluted with dehydrated 4-methyl-2-pentanol to a total volume of 200 mL. The precursor coating solution, concentration, and composition are summarized in Table 2.

[0111] The precursor coating solutions CS-e~h are stock solution S-4, stock solutions S-2 and S-3, and Sn(NMe2)4 (CS-e, CS-f, respectively) and Sn(O t Bu)4 (CS-g, CS-h) were mixed in appropriate volume ratios to obtain total Sn concentrations of 10 and 20 mol%, respectively, and then diluted with dehydrated 4-methyl-2-pentanol to obtain a total Sn concentration of 0.044 M. The precursor coating solution CS-d was prepared by directly diluting the stock solution S-4 with dehydrated 4-methyl-2-pentanol to a final concentration of 0.042 M Sn. For example, 200 mL of precursor coating solution CS-e was prepared by mixing 72.6 mL of S-4 with 7.04 mL of S-3 and diluting with dehydrated 4-methyl-2-pentanol to a total volume of 200 mL.

[0112] [Table 2]

[0113] The precursor coating solution CS-i was prepared by mixing a methanol solution containing a hydrolysate of t-butyltin oxide hydroxide, which had been previously hydrolyzed, with a 4-methyl-2-pentanol solution of a hydrolysate of i-propyltin oxide hydroxide, which had been previously hydrolyzed, and then diluting the resulting mixture to 0.03 M [Sn] using the pure solvent described in application 839. The solution thus obtained was, i PrSnO (3 / 2-(x / 2)) (OH) x Hydrolyzed product and t BuSnO (3 / 2-(x / 2)) (OH) xIt is characterized by being a blend with the hydrolysate of, where t-BuSnO (3 / 2-(x / 2)) (OH) x The proportion is 40% based on the total moles of Sn.

[0114] Example 5 - Pattern formation using a technical coating having a selected degree of radiosensitive ligand This example provides results obtained by patterning a coating produced using the coating solution prepared as described in Example 4, demonstrating that improved pattern formation was achieved at a lower radiation dose.

[0115] A tert-butyltin oxide hydroxide photoresist film, t From the precursor coating solution prepared from BuSn(NEt2)3 in Example 4, and from Sn(NMe2)4 or Sn(O t Thin films for the EUV curve were deposited from several coating solutions from Bu)4 and then exposed using EUV irradiation. The thin films for the EUV curve were deposited on a silicon wafer (100 mm in diameter) with an original oxide surface. The Si wafer was treated with hexamethyldisilazane (HMDS) vapor before deposition. t Precursor coating solutions CS-a, CS-b, and CS-c (0.070 M Sn), prepared from BuSn(NEt2)3 and 0, 10, and 20 mol% Sn(NMe2)4 according to the specifications in Table 1, were spin-coated onto a Si substrate in air at 1500 rpm, and then baked on a hot plate in air at 100°C for 2 minutes to remove residual solvent and volatile hydrolysis reaction products. The film thickness after coating and baking was measured by ellipsometry and was approximately 25–28 nm.

[0116] A linear array of 50 circular pads, each approximately 500 µm in diameter, was exposed to EUV light on each wafer using the Lawrence Berkeley National Laboratory Micro Exposure Tool. The exposure time for each pad was varied in stages, resulting in EUV doses delivered to each pad ranging from 1.38 to 37.99 mJ·cm². -2 The levels were adjusted exponentially to 7%. After exposure, the wafers were subjected to post-exposure baking (PEB) on a hot plate in air at 170°C for 2 minutes. The exposed 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 the unexposed parts of the coating. After development, a final hot plate baking was performed in air at 150°C for 5 minutes. The remaining thickness of the exposed pads was measured using a JAWoolam M-2000 spectroscopic ellipsometer. The measured thicknesses were normalized against the maximum measured resist thickness and plotted against the logarithm of the exposure dose at a series of post-exposure baking temperatures to create characteristic curves for each resist. See Figure 10. The maximum slope of the logarithmic dose curve against the normalized thickness is defined as the photoresist contrast (γ), and the dose value at which the tangent line drawn through this point is equal to 1 is the photoresist dose versus gel value (D g ) is defined as follows. In this way, the common parameters used to characterize photoresists can be approximated according to Mack, C., Fundamental Principles of Optical Lithography, John Wiley & Sons (Chichester, UK), pp. 271-272, 2007.

[0117] The curve obtained in this way clearly shows the negative contrast generated by exposure, because the thickness of the residual pad in each resist film starts at almost zero, D g This is because it reaches its maximum value near 0(D). The mole fraction of Sn in the precursor coating solution corresponding to Sn(NMe2)4 is 0(Dg = 13.8 mJ·cm -2 ) to 10% (D g = 10.6 mJ·cm -2 ) and finally 20% (D g = 5.8 mJ·cm -2 As the dose increases, it is observed that the dose required to initiate a change in development speed decreases significantly.

[0118] High-resolution line-space patterns were also printed using an EUV scanner and tert-butyltin oxide hydroxide photoresist films cast from precursor coating solutions CS-d, CS-e, and CS-f. Silicon wafers (300 mm in diameter) with the original oxide surface were used as substrates without any additional surface treatment. As previously mentioned, t BuSn(NEt2)3 and 0, 10, or 20 mol% Sn(NMe2)4 or Sn(O t Precursor coating solutions CS-d~h and CS-i, prepared from Bu)4, were spin-coated onto a Si substrate in air at 1000 rpm or 1500 rpm (CS-d only), and then baked on a hot plate in air at 100°C for 2 minutes.

[0119] The coated substrate was exposed to extreme ultraviolet light using an NXE:3300B EUV scanner (dipole 60x illumination, numerical aperture 0.33). A pattern of 16 nm lines at a 32 nm pitch was projected onto the coated wafer, followed by post-coating baking (PAB) at 100°C for 2 minutes. The exposed resist film and substrate were then subjected to PEB at 170°C for 2 minutes in air on a hot plate. The exposed film was then developed in 2-heptanone for 15 seconds, followed by washing with the same developer for another 15 seconds to form a negative image, i.e., to remove unexposed areas of the coating. After development, a final hot plate baking was performed at 150°C for 5 minutes in air. Figure 11 shows an SEM image of the resist lines developed from the tert-butyltin oxide hydroxide photoresist film obtained in this manner. t BuSn(NEt2)3(CS-d), and 10 or 20 mol% Sn(NMe2)4 (CS-e and CS-f, respectively), or Sn(O t The imaging dose, critical dimensions, and linewidth roughness are shown for each film cast from precursor coating solutions prepared from Bu)4 (CS-g, CS-h). Again, a decrease in imaging dose is observed as the proportion of SnX4 added to the precursor coating solution increases. The imaging dose required to achieve a critical dimension of 16 nm is plotted against the calculated LWR for each film cast from precursor coating solutions d-i in Figure 12. Importantly, films cast from CS-e and -f show a decrease of over 30% in the required imaging dose compared to CS-i, without an increase in linewidth-roughness (LWR). This represents a substantial improvement over pre-hydrolyzed alkyl ligand formulations and indicates a significant bypass (beyond its dose range) of the generally observed inverse correlation between patterning dose and LWR.

[0120] Example 6 - The patterning performance of coatings prepared with a mixture of tert-butyl and methyl radiosensitive ligands will be evaluated.

[0121] in particular, t Prepared by hydrolyzing a precursor solution containing BuSnX3 and MeSnX3 compounds in situ. t BuSnO (3 / 2-(x / 2)) (OH) x and MeSnO (3 / 2-(x / 2)) (OH) x The preparation of the precursor solution, coating of the film, and lithography performance were investigated in relation to an organotin oxide hydroxide photoresist film containing a mixture of [components].

[0122] From MeSnCl3(Gelest), we can convert MeSn(O t Bu)3 (FW=353.1, hereafter P-6) was synthesized. MeSnCl3 in 0.8M pentane was charged into an oven-dried RBF equipped with a dropping funnel and a magnetic stirrer bar. While cooling in an ice bath, 4 molar equivalents of diethylamine (5.5M) in pentane were added dropwise from the dropping funnel. After the addition was complete, 4 molar equivalents of a mixture of tert-butyl alcohol in pentane (3.25:1 by volume) were added, and the solution was stirred at room temperature for 30 minutes. The reaction mixture was then filtered, and volatiles were removed under vacuum to obtain the reaction product as diesel fuel. The reaction product was then distilled at 55-60°C (approximately 0.1 torr).

[0123] A stock solution of P-6 was prepared by dissolving it in dehydrated 4-methyl-2-pentanol. t Prepare the solution of Bu)3 in 4-methyl-2-pentanol, in the same manner as in the case of solution S-4 described above. tA second stock solution prepared from BuSn(NEt2)3 was mixed with the first solution in various volume ratios and diluted with the same solvent to obtain a total Sn concentration of 0.05 M. Using this method, a series of precursor solutions with total alkyl-Sn concentrations ranging from 0 to 60 mol% were prepared, with MeSn(OtBu)3 added. These precursor solutions were coated onto a 100 mm Si substrate, baked at 100°C, and then exposed to EUV irradiation at varying doses to create the contrast array described above.

[0124] After exposure, the coated wafers were baked in air at 170°C, developed in 2-heptanone for 15 seconds, washed in a wash bottle containing the same solvent for 15 seconds, dried under N2, and baked in air at 150°C for 5 minutes. The remaining thickness of each exposed pad was measured and plotted as a function of dose (Figure 13). The measured resist values ​​obtained (see Example 5) are shown in Table 2. From Figure 13, it can be seen that the higher the mol% of MeSn(OtBu)3 in the precursor solution, the higher the D g It is observed that the size decreases, but the contrast is relatively low. g Even in the case of the value, it remains high. Importantly, the remaining thickness < <D g The fact that this value is always close to zero suggests that in unexposed areas, the resist is wiped away, leaving only a minimal residue (scum).

[0125] [Table 3]

[0126] Similarly, a pattern of 18 nm lines at a 36 nm pitch was exposed to 13.5 nm wavelength radiation, dipole illumination, and a numerical aperture of 0.3 using the Lawrence Berkeley National Laboratory Micro Exposure Tool on a similarly processed wafer. Linewidth (CD) was measured using SEM and plotted against image-forming dose (Figure 14). In this case as well, the MeSn(O) in the precursor solution was used. tIt is found that as the mole fraction of Bu)3 increases, the image-forming dose required to achieve a given linewidth decreases significantly. Representative SEM images from the same wafer are shown in Figure 15 for precursor solutions containing a) 20%, b) 40%, and c) 60% P-6.

[0127] The embodiments described above are for illustrative purposes only and do not limit this specification. Additional embodiments exist in the claims. In addition, while the present invention has been described in relation to specific embodiments, variations in form and detail can be made without departing from the spirit and scope of the invention, as will be readily apparent to those skilled in the art. Any incorporation of the references above is limited and does not incorporate any subject matter contrary to the express disclosure herein. To the extent that a particular structure, composition and / or process is described herein using components, elements, components or other partitions, unless otherwise specifically stated, the disclosure herein is understood to encompass embodiments that include specific embodiments, specific components, elements, components, other partitions, or combinations thereof, and embodiments that substantially consist of such specific components, components, other partitions, or combinations thereof, including additional features that do not alter the fundamental essence of the subject matter as suggested in the description.

Claims

1. A process of depositing a tin precursor composition having a radiosensitive Sn-C bond and a hydrolyzable ligand on a substrate surface for forming an organic tin oxide-containing film. Includes, When the aforementioned film is completely hydrolyzed, the following formula is obtained: R ｚ SnO （２－（ｚ／２）－（ｘ／２）） (OH) ｘ (In the formula, 0 < (z + x) < 4 and z > 0, and R is an alkyl, cycloalkyl, or substituted alkyl moiety having 1 to 31 carbon atoms.) The composition comprises a composition formed from the hydrolysis of the tin precursor composition, represented by the following: A method for forming a radiosensitive, pattern-forming organic tin oxide-containing film, wherein the tin precursor composition contains 0.005 M to 1.4 M of tin.

2. The method according to claim 1, wherein the film comprises a Sn-OH bond, a Sn-O-Sn bond, and the radiosensitive Sn-C bond.

3. The method according to claim 1 or 2, wherein the organic tin oxide film is cleavable by at least one of UV light, EUV light, and electron beam irradiation.

4. The method according to any one of claims 1 to 3, wherein the hydrolyzable ligand comprises a halide, alkoxide, alkylamide, alkynide, azide, dialkylamide, siloxo, silylamide, disilylamide, aryloxo, amidato, amidinato, imide, or a fluorinated analog thereof or a mixture thereof.

5. The method according to any one of claims 1 to 3, wherein the tin precursor composition comprises t-butyltris(dimethylamide)tin, i-propyltris(dimethylamide)tin, t-butyltris(diethylamide)tin, i-propyltin trichloride, or a combination thereof.

6. The method according to any one of claims 1 to 5, wherein the deposition step is carried out by a gas-based deposition process including chemical vapor deposition (CVD), physical vapor deposition (PVD), or atomic layer deposition (ALD).

7. The method according to any one of claims 1 to 5, wherein the deposition step is carried out by a spin coating method, a spray coating method, a dip coating method, a knife edge coating method, a printing method, or a combination thereof.

8. A step of forming a radiosensitive organotin oxide-containing film using the method according to any one of claims 1 to 7, and The process involves patterning the film with at least one of UV light, EUV light, and electron beam irradiation to form exposed and unexposed portions where the Sn-C bond cleavage occurs in the exposed areas. Patterning methods, including those mentioned above.

9. The method according to claim 8, wherein the exposed portion is at least partially condensed compared to the unexposed portion.

10. The method according to claim 8, wherein the unexposed portion is soluble in an organic solvent.

11. The method according to claim 8, wherein the exposed portion is insoluble in organic solvents.

12. The method according to claim 8, further comprising removing at least a portion of the exposed portion in the developing step.

13. The method according to claim 12, wherein in the developing step, the exposed portion is removed using an aqueous base.

14. The organotin composition is produced by hydrolysis of a precursor composition comprising two or more organotin compounds having different hydrocarbyl ligands and ligands independently having hydrolyzable bonds with Sn. The organotin composition is given by the following formula: a1 R 1 z1 SnO (2-z1 / 2-x1 / 2) (OH) x1 + a2 R 2 z2 SnO (2-z2 / 2-x2 / 2) (OH) x2 + a3 R 3 z3 SnO (2-z3 / 2-x3 / 2) (OH) x3 (where 0 < (z1, z2, z3) ≤ 2, 0 < (x1, x2, x3) < 3, a1 > 0, a2 > 0, a3 ≥ 0, and R 1, R 2, and R 3 are independently hydrocarbyl ligands having 1 to 31 carbon atoms.) Represented by, A radiosensitive film comprising an organotin composition having a blend of two or more different hydrocarbyl ligands, where R1, R2, and R3 are different hydrocarbyl ligands.

15. The film according to claim 14, wherein the hydrocarbyl ligand comprises a linear, branched, cyclic, aryl, alkenyl, benzyl, alkynyl, heteroatomic functional group, or a combination thereof.

16. The film according to claim 15, wherein the heteroatom functional group comprises a cyano, thio, silyl, ether, keto, ester, halogenated group, or a combination thereof.

17. The film according to claim 14, wherein the hydrocarbyl ligand comprises methyl, ethyl, propyl, butyl, isopropyl, tert-butyl, sec-butyl, tert-amyl, cyclohexyl, cyclopentyl, cyclobutyl, cyclopropyl, 1-adamantyl, 2-adamantyl, or a combination thereof.

18. The film according to claim 14, wherein the hydrocarbyl ligand comprises tert-butyl, isopropyl, and / or methyl.

19. The film according to any one of claims 14 to 18, wherein the precursor composition comprises an organotin compound represented by the formula R1 y1 SnX1 4-y1 and an organotin compound represented by the formula R2 y2 SnX2 4-y2 (wherein R1 and R2 are bonded to Sn by a metal-carbon bond, 1 < (y1, y2) ≤ 2, and X1 and X2 are ligands independently having hydrolyzable bonds with Sn).

20. The membrane according to claim 19, wherein the precursor composition comprises at least 5 mole percent of each organotin compound.

21. The membrane according to claim 19, wherein the precursor composition comprises at least 20 mole percent of each organotin compound.

22. The membrane according to claim 19, wherein the precursor composition comprises three organotin compounds having different hydrocarbyl ligands.

23. The film according to claim 19, wherein the precursor composition further comprises an organotin compound represented by the formula R3y3SnX34-y3 (wherein R3 is bonded to Sn by a metal-carbon bond, 1 < (y3) ≤ 2, and X1, X2 and X3 are ligands independently having hydrolyzable bonds with Sn).

24. The film according to claim 19, wherein X1 and X2 are the same.

25. The film according to any one of claims 14 to 18, wherein the film has an average thickness of 1 nm to 250 nm, as evaluated using X-ray reflection and / or ellipsometry, and has a thickness variation of ±50% or less from the average thickness.

26. The film is the film according to any one of claims 14 to 18, having an average thickness of 2 nm to 40 nm.

27. The film according to any one of claims 14 to 18, wherein the film has a resist and has a radiation-sensitive Sn-C bond.

28. The film according to any one of claims 14 to 18, wherein the film exhibits an increase in refractive index and radiation absorption upon heat treatment, and the radiation absorption is associated with the cleavage of the Sn-C bond.

29. The membrane according to claim 28, wherein the cleavage of the Sn-C bond is related to cluster formation.

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