Multiple patterning with organometallic photopatternable layers with intermediate freeze steps

Abstract

To provide multiple patterning approaches using radiation sensitive organometallic materials.SOLUTION: In particular, multiple patterning approaches can be used to provide distinct multiple patterns of organometallic material on a hardmask or other substrate through a sequential approach that leads to a final pattern. The multiple patterning approach may proceed via sequential lithography steps with multiple organometallic layers and may involve a hardbake freezing after development of each pattern. There is described use of an organometallic resist with dual tone properties to perform pattern cutting and multiple patterning of a single organometallic layer. There are also described corresponding structures.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to co-pending U.S. Provisional Patent Application No. 63 / 020,778, filed May 6, 2020, to Stowers et al., entitled "Multiple Patterning With Organometallic Photopatternable Layers With Intermediate Freeze Steps," which is incorporated herein by reference.

[0002] This application relates to a multi-patterning approach based on metal-organic photo-patternable materials that allows for the utilization of high etch contrast. The present invention further relates to structures achievable using multilayer patterning with metal-organic radiation-patternable resists. [Background technology]

[0003] To continue shrinking the size of lithographically fabricated devices, photolithography systems have been developed to utilize extremely short wavelength extreme ultraviolet light, which can enable the creation of very small features. Metalorganic coatings have been shown to be useful photoresist materials suitable for achieving high-resolution patterning and are very promising for commercial use not only for electron beam patterning but also for patterning using extreme ultraviolet light. To fully utilize metalorganic resists, practical improvements in processing in a commercial environment will enable the full potential of these materials to be utilized.

[0004] Multi-patterning methods are increasingly being used to fabricate integrated devices with high density and high resolution features. Generally, integrated circuit performance improves with reduced device size and increased device density, and therefore, it is desirable to reduce the size of the printed features that define individual devices and increase the associated feature density. However, as the desired patterned features become smaller and approach the resolution limits of a given exposure source, such as extreme ultraviolet (EUV), it becomes more difficult to resolve the features with sufficient precision and fidelity. Summary of the Invention [Means for solving the problem]

[0005] The invention described herein relates to multi-patterning approaches using metal-organic photopatternable materials and the structures achievable using these approaches.

[0006] In a first aspect, the present invention relates to a method of patterning a substrate, the method comprising: irradiating a layer of a photosensitive composition over a patterned understructure to form a latent image, the photosensitive composition comprising an organometallic composition having a radiation-sensitive ligand bonded to a metal, the patterned understructure comprising, in order, a substrate, an unpatterned hard mask layer on the substrate, and a patterned metal oxide-based material having a first pattern on the hard mask layer, the photosensitive composition being located on the hard mask layer together with the patterned metal oxide-based material, the pattern corresponding to the latent image being different from the first pattern, and the hard mask layer having a differential etch with respect to the irradiated photosensitive composition and the patterned metal oxide-based material; and developing the latent image to form a second pattern from the irradiated photosensitive composition to form a developed structure.

[0007] In a further aspect, the invention relates to a structure comprising: a substrate; an unpatterned hardmask coating on the substrate; a first pattern of a first tin oxide based material on the hardmask coating, wherein gaps in the first pattern do not cover the hardmask; and a second pattern of a second tin oxide based material on the hardmask coating comprising the first pattern, wherein the second pattern differs from the first pattern, provided that the second pattern does not overlap the first pattern, and wherein the linewidth roughness of the first pattern is less than ¼ of the inter-feature distance of the first pattern.

[0008] In an additional aspect, the invention relates to a method of forming a patterned structure using radiation-based lithography, comprising performing a positive tone development step on a latent image formed in a patterning composition, such as a metalorganic patterning composition, deposited on a patterned metal composition supported by the structure, wherein the positive tone development step removes the irradiated portions of the latent image in the metalorganic patterning composition and the exposed portions of the patterned metal composition to form a cut pattern in the patterned metal composition.

[0009] In another aspect, the invention relates to a method of forming a patterned structure, the method comprising: irradiating a structure including a layer of organometallic radiation-sensitive material and a substrate according to a first pattern to form a first latent image; further irradiating the structure including the first latent image according to a second pattern to form a second latent image superimposed on the first latent image, wherein the first latent image and the superimposed second latent image form a composite latent image; and developing the structure including the composite latent image to form a patterned structure. [Brief explanation of the drawings]

[0010] [Figure 1A] FIG. 1 is a diagram of a half pitch line-space pattern that can be formed via the metal oxide-freeze-metal oxide process disclosed herein. [Figure 1B]FIG. 2 is a diagram of a cross-hatched pattern that can be formed via the metal oxide-freeze-metal oxide process disclosed herein. [Figure 1C] FIG. 1 is a diagram of a hexagonal array pattern that can be formed via the metal oxide-freeze-metal oxide process disclosed herein. [Figure 1D] FIG. 1 is a diagram of a mixed pillar and line-space pattern that can be formed via the metal oxide-freeze-metal oxide process disclosed herein. [Figure 1E] FIG. 1 is a diagram of a line cut pattern that can be formed via the double patterning process disclosed herein. [Figure 2A] 1 is a flow chart of the litho-freeze-litho-freeze process. [Figure 2B] 1 is a flowchart of a lithography cutting process. [Figure 3] FIG. 10 is a side plan view of a flow for a "thermal freeze" double patterning process in which a bake makes a first patterning layer insoluble to a second layer. [Figure 4] FIG. 1 is a schematic perspective view of a radiation-patterned structure including a latent image. [Figure 5] FIG. 5 is a side plan view of the structure of FIG. [Figure 6] FIG. 5 is a schematic perspective view of the structure of FIG. 4 after the latent image has been developed and the unexposed photosensitive organometallic material has been removed to form a patterned structure. [Figure 7] FIG. 7 is a side view of the patterned structure of FIG. 6. [Figure 8] FIG. 7 is a schematic perspective view of the patterned structure of FIG. 6 upon which a second layer of photosensitive organometallic material has been deposited. [Figure 9] FIG. 9 is a side view of the structure of FIG. 8. [Figure 10] 9 is a schematic perspective view of the radiation-patterned structure of FIG. 8, including a latent image in the second photosensitive organometallic layer parallel to the first pattern. [Figure 11] FIG. 11 is a side plan view of the structure of FIG. 10. [Figure 12]FIG. 11 is a schematic perspective view of the structure of FIG. 10 after developing the latent image and removing the unirradiated photosensitive organometallic material from the second photosensitive organometallic layer to form double-patterned line features in the hard mask coated substrate. [Figure 13] FIG. 13 is a side view of the structure of FIG. 12. [Figure 14] FIG. 13 is a schematic perspective view of a patterned structure having a hard mask etched into a pattern according to the structure of FIG. 12. [Figure 15] FIG. 15 is a side view of the structure of FIG. 14. [Figure 16] 9 is a schematic perspective view of the radiation-patterned structure of FIG. 8 including a latent image in a second photosensitive organometallic layer perpendicular to the first pattern. [Figure 17] FIG. 17 is a side plan view of the structure of FIG. 16. [Figure 18] FIG. 17 is a schematic perspective view of the structure of FIG. 16 after the latent image has been developed to remove the unirradiated photosensitive organometallic material from the second photosensitive organometallic layer to form a double-patterned crosshatch structure in the hardmask-coated substrate. [Figure 19A] FIG. 19 is a side view of the structure of FIG. 18. [Figure 19B] FIG. 19 is a cross-sectional view of the structure of FIG. 18 along plane BB. [Figure 19C] FIG. 19 is a cross-sectional view of the structure of FIG. 18 along plane CC. [Figure 20] FIG. 19 is a schematic perspective view of a patterned structure having a hard mask etched into a pattern according to the structure of FIG. 18. [Figure 21] FIG. 21 is a side plan view of the structure of FIG. 20. [Figure 22A] FIG. 1 is a schematic representation of a patterned structure having an organometallic material that has been exposed to patterned radiation and developed. [Figure 22B] FIG. 22B is a side view of the structure of FIG. 22A. [Figure 22C] 22B is a schematic diagram of the structure of FIG. 22A after a layer of photosensitive organometallic material has been deposited and patterned with radiation to form a latent image. [Figure 22D] FIG. 22D is a side view of the structure of FIG. 22C. [Figure 22E] 22D is a schematic representation of the structure of FIG. 22C after development of the organometallic material irradiated according to the latent image of FIG. 22C. [Figure 22F] 22B is a schematic diagram of the line-cut structure of FIG. 22A shown after removal of the unirradiated photosensitive organometallic material from the organometallic layer of FIG. 22E. [Figure 23A] FIG. 1 is a schematic diagram of a radiation-patterned structure including a latent image. [Figure 23B] FIG. 1 is a schematic diagram of a radiation-patterned structure including a composite latent image. [Figure 23C] FIG. 23C is a schematic diagram of the structure of FIG. 23B after development of the composite latent image with a negative developer. [Figure 23D] FIG. 23D is a schematic diagram of a patterned structure having a hard mask etched into a pattern according to the structure of FIG. 23C. [Figure 24A] FIG. 1 is a schematic diagram of a radiation-patterned structure including a latent image. [Figure 24B] FIG. 1 is a schematic diagram of a radiation-patterned structure including a composite latent image. [Figure 24C] FIG. 24C is a schematic diagram of the structure of FIG. 24B after development of the composite latent image with a positive developer. [Figure 24D] FIG. 24D is a schematic diagram of a patterned structure having a hard mask etched into a pattern according to the structure of FIG. 24C. [Figure 25] 1 is a CD-SEM image of a cross-hatched tin oxide pattern produced by the double patterning process described in the Examples. DETAILED DESCRIPTION OF THE INVENTION

[0011] The properties of organometallic radiation-sensitive resist compositions are utilized for advantageous multi-patterning processes to form desired structures containing multiple patterns. In some embodiments, a hard mask layer between the resist composition and the substrate provides more effective pattern transfer, allowing for a variety of substrate compositions. In particular, high-etch-contrast organometallic radiation-sensitive resists have been developed that can be cured to form metal oxide-based compositions with increasing degrees of oxidation based on process conditions. These organometallic resists can be used to form high-resolution patterns. After a first pattern is formed, a freezing step can be performed, such as by heating the patterned structure to further dehydrate the resist and form a metal oxide or a more oxidized composition that is structurally closer to a metal oxide composition. In an alternative embodiment, a freezing step is not performed after the first patterning step to facilitate cutting of the first pattern in a second patterning step. In some embodiments, the frozen structure is desirably stable against deposition and patterning of another layer of organometallic resist composition. Following deposition of an additional layer of resist composition, the second layer is again patterned through radiation exposure and development. In additional embodiments, a single resist layer can be exposed through multiple masks, followed by a single development step to develop the latent images formed through the multiple masks. Organometallic resists can be effectively used to form high-resolution patterns and can be useful for EUV patterning. Suitable resists can be used for both negative and positive patterning to effectively enable more multiple patterning options using the same composition for predictable and reproducible multiple patterning, although adjustments to the resist composition can be made to optimize subsequent patterning steps. Post-treatment or intermittent treatments can be used to improve pattern quality.

[0012] Multi-patterning techniques can be used to improve pattern resolution and expand the practical patterning capabilities achievable with a particular patterning system. A first pattern can form various features, which may be in a regular pattern, such as a striped pattern. A second pattern can overlap, be located within, or be a combination of overlapping and within the first pattern. Alternatively, the second pattern can be used to cut the first pattern. Successive patterning steps generally allow for the formation of structures not easily formed in a single patterning step, achieving higher resolution or more complexly arranged features. A third or more patterning steps may be performed if desired. On a practical level, there is a limit to the number of successive patterning steps that will provide well-defined and properly developed features, but creative mask shaping can expand the number of useful patterns, so multi-patterning can generally involve two, three, four, five, six, seven or more patterning steps on a single layer of hard mask on a substrate.

[0013] Furthermore, compatible positive tone patterning can provide a cutting step as a multiple patterning step, where one or more cutting steps using positive tone patterning can be performed after a single negative tone patterning step or multiple consecutive negative tone patterning steps, or can be interleaved as a cutting step between one or more initial negative tone patterning steps and one or more subsequent negative tone patterning steps. Positive tone patterning as a cutting step can be performed using an organometallic patterning composition or an organic photoresist such as a chemically amplified resist, as described further below. The high development contrast of organometallic patterning compositions can be used to perform multiple patterning using two or more exposure steps using different masks, followed by a development step of the latent images formed from the multiple exposures. Such multiple patterning in the form of multiple exposures followed by development can be combined with additional negative tone patterning steps and positive tone cutting steps, as described herein.

[0014] The formation of integrated electronic devices and the like typically involves patterning materials to form individual elements or components within the structure. This patterning may involve covering selected portions of stacked layers that abut one another vertically and / or horizontally with different compositions to introduce desired functionality. Various materials may comprise semiconductors, which may have selected dopants, dielectrics, conductors, and / or other types of materials. To form a final component, such as an integrated circuit, typically many layers are formed and patterned to form a final structure with different materials at locations defined both by their location within the stack and by their location along the substrate.

[0015] To form high-resolution patterns, radiation-sensitive organic compositions can be used to introduce patterns, and portions of the composition can be treated to resist development / etching, allowing for selective material removal to introduce selected patterns; the composition can be referred to as a resist. Irradiation with a selected pattern or a negative of the pattern can be used to expose the resist to form a pattern or latent image with developer-resistant and developer-soluble regions. The radiation-sensitive organometallic compositions described herein can be used for the direct formation of desired inorganic material structures within devices and / or as radiation-patternable organometallic resists. In either case, significant processing improvements can be utilized, and the structure of the patterned metal oxide-based material can also be improved.

[0016] While several multi-patterning methods, such as spacer-aligned double patterning (SADP) and spacer-aligned quadruple patterning (SAQP), are known in the art, these approaches typically require multiple processing steps, which can increase manufacturing costs and lead to patterning defects. Therefore, a patterning approach that can improve patterning performance without significantly increasing processing complexity is desirable. An efficient multi-patterning approach that takes advantage of the high etch contrast afforded by new generation resist materials is described herein. Below, the more efficient patterning approaches available using next-generation patternable materials are contrasted with traditional multi-patterning approaches.

[0017] In particular, organometallic photoresists, such as metal oxide hydroxide compositions with radiation-sensitive ligands, enable methods for performing multiple patterning steps using a freeze process, such as a thermal freeze process, for appropriate embodiments. In a freeze process, a first photoresist layer is deposited, exposed, and developed to form a first pattern. The first pattern then undergoes a process to "freeze" the pattern; suitable freeze processes can be exposure to blanket UV light and / or a thermal bake step. After forming the first pattern, a second layer of photoresist can be deposited and also exposed and developed to result in a second pattern. By combining two or more photoresist freeze processes, selected patterns can be achieved that would otherwise require cumbersome processes such as spacer-aligned multiple patterning (SAMP) or other processes requiring one or more intermediate etching or deposition processes.

[0018] Metal oxide hydroxide compositions can exhibit either positive-tone patterning or negative-tone patterning behavior. In negative-tone patterning, exposure to radiation converts the irradiated coating material into a material that is more resistant to removal using a developer composition compared to the non-irradiated coating material. In positive-tone patterning, the exposure sufficiently changes the polarity of the exposed coating material, e.g., makes it more polar, so that the exposed coating material can be selectively removed with an aqueous or other highly polar solvent. Selective removal of at least a portion of the coating material leaves a pattern in which multiple regions are removed to expose the underlying substrate.

[0019] Negative-tone patterning is particularly desirable for lower layers in multiple patterning processes because the first patterned and developed layer is not significantly affected by further irradiation in subsequent patterning steps. If the pattern in the lower layer is a positive-tone resist, the resist may be further altered by subsequent irradiation steps. Therefore, if the positive-tone pattern in the lower layer is not protected by a hard mask or the like during development of the upper layer, the lower layer pattern may be damaged in the subsequent development step. Therefore, organometallic resists that can be used for negative-tone patterning with small feature sizes are particularly suitable for multiple patterning with fewer process steps. The ability to use a positive-tone development process using organometallic patterning compositions in subsequent patterning steps allows for cutting of previously formed patterns, providing additional process advantages for organometallic patterning compositions for multiple patterning processes.

[0020] Suitable photoresists can be based on metal oxide chemistries (metal oxo / hydroxo compositions) with radiation-sensitive ligands to control resist stability and processability. Generally, these resist compositions function as negative-tone photoresists when developed with organic solvents. Suitable resist compositions can have peroxo ligands to impart radiation sensitivity. Peroxo-based resist compounds are described in U.S. Pat. No. 8,415,000 B2 to Stowers et al., entitled "Patterned Inorganic Layers, Radiation-Based Patterning Compositions and Corresponding Methods," and U.S. Pat. No. 8,703,386 B2 to Bass et al., entitled "Metal Peroxo Compounds With Organic Co-ligand for Electron Beam, Deep UV, and Extreme UV Photoresist Applications," both of which are incorporated herein by reference. Although tin compositions are exemplified herein and the data presented herein focuses on tin-based resists, the processing approaches and developer compositions described herein can be expected to be effective for other metal-based resists, such as those described above and below.

[0021] Organometallic photoresists, such as organotin oxide hydroxides, have been shown to have excellent properties as photoresists for use in lithographic photopatterning. Suitable organometallic photoresists include the organotin materials described in U.S. Patent No. 9,310,684 B2 to Meyers et al., entitled "Organometallic Solution Based High Resolution Patterning Compositions," U.S. Patent No. 10,642,153 to Meyers et al., entitled "Organometallic Solution Based High Resolution Patterning Compositions and Corresponding Methods," and U.S. Patent No. 10,228,618 B2 to Meyers et al., entitled "Organotin Oxide Hydroxide Patterning Compositions, Precursors, and Patterning," all of which are incorporated herein by reference. Other organometallic patterning compositions based on various metals are described in U.S. Patent Application Publication No. 2002 / 0076495 to Maloney et al., entitled "Method of Making Electronic Material," and U.S. Patent Application Publication No. 9,372,402 B2 to Freedman et al., entitled "Molecular Organometallic Resists for EUV," both of which are incorporated herein by reference. Resists having metal oxide nanoparticles encapsulated in an organic shell-like coating are described in U.S. Patent Application Publication No. 2015 / 0234272 A1 to Sarma et al., entitled "Metal Oxide Nanoparticles and Photoresist Compositions," which is incorporated herein by reference. Applicant has developed highly advanced organotin patterning materials, some of which are exemplified compositions.

[0022] Suitable organotin materials have the formula R z SnO (2-(z / 2)-(x / 2)) (OH) x(where 0 < z ≦ 2 and 0 < (z + x) ≦ 4, and R is a hydrocarbyl group having 1 to 31 carbon atoms, or for N different compositions, R N and those blends containing different R groups that can be written as) may be based on the chemical properties of the radiation-sensitive patterning composition represented thereby. In the coating layer, the composition can be incorporated into a common oxo / hydroxone network. R forms a carbon-tin bond and R can contain heteroatoms other than carbon or hydrogen. In particular, branched alkyl ligands are such that the compound is R 1 R 2 R 3 CSnO (2-(z / 2)-(x / 2)) (OH) x (where R 1 and R 2 are each independently an alkyl group having 1 to 10 carbon atoms, and R 3 is hydrogen or an alkyl group having 1 to 10 carbon atoms) may be desirable for some patterning compositions. As will be described later, this representation of the alkyl ligand R generally applies equally to other embodiments using R 1 R 2 R 3 CSn(X)3, where X corresponds to a hydrolyzable ligand such as an alkoxide or amide moiety. In some embodiments, R 1 and R 2 can form a cyclic alkyl moiety and R 3 can also be bonded to other groups in the cyclic moiety. Suitable branched alkyl ligands are, for example, isopropyl (R 1 and R 2 are methyl and R 3 is hydrogen), tert-butyl (R 1 , R 2 and R<00​​​​​​​​​​​​is hydrogen), neopentyl (R 1 and R 2 is hydrogen and R 3 is -C(CH3)3), cyclohexyl, cyclopentyl, cyclobutyl, and cyclopropyl. 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 attached to the metal at a tertiary carbon) and 2-adamantyl (-CH(CH)2(CH2)4(CH)2(CH2) or tricyclo(3.3.1.13,7)decane attached to the metal at a secondary carbon). In other embodiments, the hydrocarbyl group may include an aryl or alkenyl group, such as benzyl or allyl, or an alkynyl group. In other embodiments, the hydrocarbyl ligand R may include any group consisting solely of C and H and containing 1 to 31 carbon atoms. In summary, some examples of suitable alkyl groups bonded to tin include, for example, linear or branched alkyl (i-Pr((CH3)2CH-), t-Bu((CH3)3C-), Me(CH3-), n-Bu(CH3CH2CH2CH2-)), cycloalkyl (cyclopropyl, cyclobutyl, cyclopentyl), olefin (alkenyl, aryl, allyl), or alkynyl groups, or combinations thereof. In further embodiments, suitable R groups can include hydrocarbyl groups substituted with heteroatom functional groups including cyano, thio, silyl, ether, keto, ester, or halogenated groups, or combinations thereof. As is conventional in the art, hydrocarbyl groups can be referred to as alkyl groups even though the groups can have unsaturated bonds, aryl groups, heteroatoms, etc., and thus, a mono-alkyl compound / composition refers to a compound / composition where z=1.

[0023] Precursor compositions can be employed to form organotin oxo / hydroxo coating compositions that are incorporated into a common oxo / hydroxo network. The precursor compositions can include one or more soluble organotin oxo / hydroxo compounds or corresponding compounds having hydrolyzable ligands that form oxo and / or hydroxo ligands upon hydrolysis. In the case of precursor compositions containing multiple compounds, the compounds can have different organic ligands with metal-carbon bonds and the same or different hydrolyzable ligands. Thus, precursor compositions that form radiation-sensitive coatings can include R N SnX 4-n (wherein n=1, 2, or 3, R is a hydrocarbyl group having 1 to 31 carbon atoms as described above, and X is a ligand having a hydrolyzable MX bond), and solutions of mixtures thereof. Suitable hydrolyzable ligands include, for example, alkynides (R 0 C≡C-), alkoxides (R 0 O-), carboxylate (R 0 COO-), a halide, a dialkylamide, or a combination thereof, wherein R 0 The group can be one of the same moieties described above for R. In particular, the organotin trialkoxide composition has the formula RSn(OR 0 )3. Also, organotin tridialkylamide compositions can be represented by the formula RSn(NR a R b )3(wherein, R a Groups and R b The group can be one of the same moieties described above for R. In some embodiments, the organotin precursor composition described above can comprise MX4 and / or MO ((m / 2)-l / 2) (OH) l (In the formula, 0 <z≦2、0<(z+w)≦4、m=M m+ where 0≦l≦m and M=M′ or Sn, where M′ is a non-tin metal of Groups 2-16 of the Periodic Table.

[0024] Generally, organotin photoresists exhibit both high resolution and high etch resistance, enabling the formation of small features and patterns. In situ hydrolysis can be used during or after the coating process to hydrolyze any hydrolyzable MX bonds to form oxo / hydroxo networks in the coating prior to patterning. The precursor compounds can also form clusters in solution with appropriate ligand rearrangements, where at least a portion of the hydrolyzable ligands may be substituted with oxo bridges or hydroxyl groups, e.g., three tin atoms, as described in U.S. Patent Application Publication No. 2019 / 0053001, entitled "Organotin Clusters, Solutions of Organotin Clusters, and Application to High Resolution Patterning," by Cardineau et al., and U.S. Patent Application Publication No. 2019 / 0308998, entitled "Tin Dodecamers and Radiation Patternable Coatings With Strong EUV Absorption," by Cardineau et al., both of which are incorporated herein by reference.

[0025] The compositions described above can be used to deposit and form layers of coating materials through various means known to those skilled in the art, as well as post-processing of the precursors onto selected structures. Typically, the structure comprises a substrate having a hard mask coating on its surface. The hard mask surface provides patterning uniformity while undergoing multiple patterning steps performed to reduce the size of the pattern features. The hard mask layer can comprise a material that has good etch contrast with the resist being patterned. In some embodiments, the hard mask is designed to be eventually removed, but in some embodiments, the patterned portions of the hard mask must be maintained for subsequent processing. The selection of the hard mask can be based on compatibility with, and possibly etch contrast with, the material below the hard mask in the substrate, which itself may be patterned with a different material.

[0026] Multi-patterning with the organometallic resists described herein offers significant flexibility in efficiently providing high-resolution patterning based on high development contrast and good radiation absorption. Various embodiments of multi-patterning can be effectively utilized to form a variety of final desired patterns. The use of tin-based organometallic patterning compositions, improved developers, and improved pattern quality after development can be utilized to reduce pattern imperfections.

[0027] Coating Properties and Coating Formation Deposition processes for forming radiation-patternable layers can be solution-based or vapor-based. Substrates generally present a surface onto which a coating material can be deposited, and substrates can include multiple layers. In some embodiments, the substrate surface may be treated to prepare the surface for the attachment of the coating material. Additionally, the surface can be cleaned and / or smoothed as appropriate. Suitable substrate surfaces can include any reasonable material. Some substrates of particular interest include, for example, silicon wafers, silica substrates, other inorganic materials, polymeric substrates such as organic polymers, composites thereof, and combinations thereof across the entire surface of the substrate and / or in layers. While wafers, such as relatively thin cylindrical structures, can be convenient, structures of any reasonable shape can be used. Polymer substrates, or substrates having a polymer layer on a non-polymeric structure, are desirable for certain applications based on their low cost and flexibility, and suitable polymers can be selected based on the relatively low processing temperatures that can be used to process the patternable materials described herein. Suitable polymers can include, for example, polycarbonates, polyimides, polyesters, polyalkenes, copolymers thereof, and mixtures thereof.

[0028] In some embodiments, a hard mask layer is formed on the substrate prior to deposition of the radiation-patternable coating. The hard mask layer may have an average thickness of about 1 nm to about 200 nm, in further embodiments about 2 nm to about 150 nm, in other embodiments about 2.5 nm to about 100 nm, and in additional embodiments about 3 nm to about 75 nm. Those skilled in the art will recognize that other ranges within the above explicit average thickness ranges are contemplated and are within the scope of the present disclosure. To achieve a desired pattern in a desired substrate (e.g., silicon), a desired hard mask material is typically selected for its etch properties relative to other layers. Generally, hard mask materials are selected and applied to a film stack based on their etch "color," where "color" refers to their etch sensitivity to a given etch chemistry.

[0029] Suitable materials for hard mask layers may include, for example, titanium nitride (TiN), silicon nitride (Si3N4), tantalum nitride (TaN), silicon oxide (SiO2, spin-on glass, silicon oxynitride), carbon-rich materials (e.g., spin-coated carbon (SOC), CVD carbon layers), etc., although various other materials may also be suitable. With regard to differential etching, for example, silicon oxide-type materials have measurable etch rates in F-containing plasmas, while carbon-rich materials do not. Similarly, carbon-rich materials can be readily etched by O-containing plasmas, while silicon oxide is resistant. TiN can be etched by Cl-containing plasmas, while SiO2 is resistant. Different final patterns may suggest different etch stacks; for example, a complex logic pattern with many line, space, and rectangular features may be patterned using a different film stack than a memory pattern consisting of an array of dots or holes. The holes may be approximately circular, rectangular, square, or any other reasonable shape. Based on the teachings herein, selection of appropriate hard mask materials, stack configurations, etch chemistries, and their relative etch differentials will be known by those skilled in the art and are within the scope of this disclosure.

[0030] Hard masks can be deposited using vapor deposition methods such as chemical vapor deposition (CVD), physical vapor deposition (PVD), or atomic layer deposition (ALD), or solution-based coating methods such as spin-on glass or spin-on carbon. Spin-on carbon (SoC) generally refers to a high-carbon composition that can be deposited as a liquid, typically containing, for example, a high-carbon polymer or molecules such as fullerenes, which are commercially available as spin-on carbon from Irresistible Materials, Ltd., UK. Spin-on glass materials are commercially available, for example, from Desert Silicon (Arizona, USA). Spin-on glass compositions include a polysilazane polymer in a suitable organic solvent, such as an ether or aromatic solvent, which can be cured in an oxygen atmosphere to form silicon oxide. Polysilazane compositions for spin-on glass are described in U.S. Pat. No. 7,270,886 to Lee et al., entitled "Spin-On Glass Composition and Method of Forming Silicon Oxide Layer Semiconductor Manufacturing Process Using the Same," which is incorporated herein by reference. Spin-on-glass formulations containing polyorganosiloxanes are described in U.S. Pat. No. 5,302,198 to Allman, entitled "Coating Solution for Forming Glassy Layers," which is incorporated herein by reference. Suitable silica-based sol-gel compositions are known in the art and can be used as spin-on-glass compositions. For example, sol-gel compositions for forming silica glass materials are described in U.S. Patent Application Publication No. 2002 / 0157418 to Ganguli et al., entitled "Process for Reducing or Eliminating Bubble Defects in Sol-Gel Silica Glass," which is incorporated herein by reference. Spin-on-glass compositions can be thermally cured in an oxygen-containing atmosphere to form quartz glass.Silica glass is commonly deposited in a variety of backgrounds using chemical vapor deposition (CVD) or other processes known in the art.

[0031] Additionally, suitable substrates may include a previously formed metalorganic photoresist pattern. Furthermore, substrates may also include pre-patterned structures, as described in U.S. Pat. No. 10,649,328 to Stowers et al., entitled "Pre-Patterned Lithography Templates, Processes Based on Radiation Patterning Using the Templates and Processes To Form the Templates," and U.S. Pat. No. 9,005,875 to Bristol et al., entitled "Pre-Patterned Hardmask for Ultrafast Lithographic Imaging," both of which are incorporated herein by reference. Generally, a substrate may comprise multiple layers of different or partially different compositions, where each layer may itself be patterned with components or portions of components that may be integrated with further components or portions of components, for example, based on further lithographic processing to pattern additional layers on and / or within the substrate.

[0032] Examples of suitable deposition methods for organometallic resists include solution processing methods, such as spin coating or dip coating, or vapor deposition methods, such as atomic layer deposition (ALD), physical vapor deposition (PVD), or chemical vapor deposition (CVD) processes, which can be used to form organometallic coatings. If solution processing is desired, the organotin composition is desirably dissolved in a solvent to aid in the vapor deposition process. Generally, the desired organotin composition can be dissolved in an organic solvent, such as alcohols, aromatic and aliphatic hydrocarbons, esters, or combinations thereof. In particular, suitable 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), mixtures thereof, and the like. In general, the choice of organic solvent may be influenced by solubility parameters, volatility, flammability, toxicity, viscosity, and potential chemical interactions with other process materials. After the components of the solution are dissolved and intermixed, the nature of the species may, in some embodiments, change as a result of partial in situ hydrolysis, hydration, and / or condensation. When the composition of a solution is referred to herein, the reference is to the components as they are added to the solution, as solvolysis and ligand metathesis may occur in complex formulations or produce polynuclear metal species in solution that may not be fully characterized. In certain applications, it is desirable for the organic solvent to have a flash point of about 10° C. or greater, in further embodiments about 20° C. or greater, and in further embodiments about 25° C. or greater, and a vapor pressure at 20° C. of about 10 kPa or less, in some embodiments about 8 kPa or less, and in further embodiments about 6 kPa or less. One of ordinary skill in the art will recognize that other ranges of flash point and vapor pressure within the above explicit ranges are contemplated and are within the scope of the present disclosure.

[0033] In some embodiments, a vapor deposition process can involve reacting one or more metal-containing precursors with or with small-molecule gas-phase reagents, such as HO, HO, O, O, CO, CO, or CHOH, which serve as O and H sources for the production of oxides and hydroxide oxides. In a CVD process, two or more reactant gases are typically mixed in a chamber near the substrate surface. Therefore, reaction conditions can be designed to be sufficiently stable to suppress undesired gas-phase reactions and nucleation. ALD precursors, introduced individually and sequentially into the reaction chamber, typically react with chemisorbed co-precursors or decomposition products to saturate the substrate surface. N SnX (4-n) Desirable characteristics of a precursor include, for example, sufficient volatility for vapor transport within the system, thermal stability to prevent premature decomposition, and / or appropriate reactivity with co-precursors to generate the target product under given process conditions. The pressure and temperature within the reaction chamber can be selected to control the reaction process. Generally, precursors with relatively low vapor pressures can be introduced using vapor flow, aerosol, and / or direct liquid injection into the evaporation chamber. A flash evaporator can be used to introduce a controlled amount of precursor vapor into the reaction chamber, correspondingly controlling the reaction process within the chamber. Secondary reactants to drive hydrolysis / oxidation can be introduced into the chamber through a separate inlet. Commercially available CVD equipment can be adapted for this purpose, or specific equipment can be used. To facilitate deposition, the substrate may be heated or cooled depending on the precursor's properties. Inert gases such as N2 and Ar can be used in appropriate volumes as carrier gases, purge gases, or pressure-regulating gases in both sequential and continuous flow regimes.

[0034] If vapor deposition is desired, the organotin precursor can be selected for desired deposition susceptibility properties, such as volatility and reactivity, through the selection of radiation-sensitive ligands (alkyl groups), and hydrolysis-sensitive and / or oxidizable ligands. Examples of suitable compositions are similar to those described above for forming organotin solutions; for example, precursor compositions that form radiation-sensitive coatings can be prepared using RN SnX 4-n where n=1, 2, or 3, R is a hydrocarbyl group having 1 to 31 carbon atoms as described above, and X is an oxidizable ligand and / or a ligand having a hydrolyzable MX bond, and mixtures thereof. The vapor deposition process can be controlled to provide the desired coating thickness.

[0035] In solution-based deposition, the thickness of the coating may generally be a function of process parameters such as the concentration, viscosity, and spin speed of the precursor solution. In other coating processes, such as vapor deposition, the thickness may also generally be adjusted through the selection of deposition and coating parameters such as flow rate, cycle time, number of cycles, etc. In some embodiments, it may be desirable to use thin coatings to facilitate the formation of small, high-resolution features.

[0036] In some embodiments, the coating material can have an average dry thickness before development of about 1 micron or less, in further embodiments about 250 nanometers (nm) or less, in additional embodiments about 1 nanometer (nm) to about 100 nm, in further embodiments about 1 nm to about 50 nm, in other embodiments about 1 nm to about 40 nm, and in some embodiments about 1 nm to about 25 nm. The range of post-development coating thickness for the exposed regions generally falls within the same ranges presented above, recognizing that development may remove a relatively small amount of exposed material. Generally, in a multiple-patterning process, each coating layer of the radiation-patternable composition can fall within these dry thickness ranges. In a multiple-patterning process, subsequent patternable coatings can have the same or different average thicknesses relative to the previous patternable coating. One of ordinary skill in the art will recognize that other ranges of solution concentrations and thicknesses within the explicit ranges above are contemplated and are within the scope of the present disclosure. Thickness can be assessed based on the optical properties of the film using non-contact methods of X-ray reflectivity and / or ellipsometry. For radiation-patternable layers that follow on top of a previously patterned layer, the average thickness is evaluated relative to the existing patterned surface extending upward from the surface relative to the plane of the structure, recognizing that the subsequent layer may not be generally planar.

[0037] For multi-patterning using a positive resist to cut the initial pattern, the positive resist can effectively be an organometallic photoresist, such as the same or similar resist used for the initial negative patterning, or an organic positive resist can be used, such as a DNQ-novolac resin, which is a blend of diazonaphthoquinone (DNQ) and a novolac resin (phenol formaldehyde resin). Commercial formulations of these positive resists are available, for example, from Fujifilm Holdings America Corp.

[0038] After the deposition and formation of an organotin coating or other organometallic coating, an edge bead removal (EBR) rinse step can generally be used. EBR processing is typically performed after photoresist deposition and before any thermal treatment or bake, and involves rinsing the peripheral edge of the wafer or substrate with a solvent to remove the photoresist in selected areas. EBR and backside rinse involve applying an edge bead rinse solution to the edge as well as the backside of the wafer, as described in U.S. Pat. No. 10,627,719 to Waller et al., entitled "Methods of Reducing Metal Residue in Edge Bead Region from Metal-Containing Resists," which is incorporated herein by reference.

[0039] A soft bake or post-apply bake (PAB) is typically performed prior to radiation exposure to hydrolyze hydrolyzable bonds in the precursor composition and / or further drive off solvent and promote densification of the coating material. In some embodiments, the PAB can be performed at a temperature of from about 25°C to about 250°C, in additional embodiments from about 50°C to about 200°C, and in further embodiments from about 80°C to about 150°C. The post-exposure bake can generally be performed for at least about 0.1 minutes, in further embodiments from about 0.5 minutes to about 30 minutes, and in additional embodiments from about 0.75 minutes to about 10 minutes. A person of ordinary skill in the art will recognize that additional ranges of PAB temperatures and times within the above explicit ranges are contemplated and are within the present disclosure. In particularly interesting embodiments, the coated materials generally comprise polymeric metal oxo-hydroxo networks based on the bonding of oxo-hydroxo ligands to metals where the metals also bear some organic (hydrocarbyl) ligands, or molecular solids composed of polynuclear metal oxo-hydroxo species bearing organic (hydrocarbyl) ligands.

[0040] Patterning and development Generally, selected organometallic photoresist coatings can be patterned using radiation. Suitable radiation sources include extreme ultraviolet (EUV), ultraviolet (UV), or electron beam (EB) radiation. In semiconductor device fabrication, EUV radiation may be desirable due to its higher resolution compared to UV radiation and higher throughput compared to electron beam (EB)-based processes. The radiation can generally be directed at the substrate through a mask, or the radiation beam can be controlled and scanned across the substrate to form a latent image in the resist coating. This section describes the general principles of patterning organometallic coatings to form patterned metal oxide-based materials, and the next section describes specific processes for multi-patterning.

[0041] According to International Standard ISO 21348 (2007), which is incorporated herein by reference, ultraviolet radiation spans wavelengths between 100 nm and less than 400 nm. Krypton fluoride lasers can be used as a source of 248 nm ultraviolet light. The ultraviolet range can be further subdivided in several ways under accepted standards, such as extreme ultraviolet (EUV) from 10 nm to less than 121 nm and far ultraviolet (FUV) from 122 nm to less than 200 nm. The 193 nm line emitted by argon fluoride lasers can be used as a radiation source in the FUV range. EUV light is used for lithography at 13.5 nm and is generated from Xe or Sn plasma sources excited using high-energy lasers or discharge pulses. Commercial sources of EUV photons include scanners manufactured by ASML Holding NV in the Netherlands. Soft x-rays can be defined as wavelengths between 0.1 nm and less than 10 nm. Light is directed through the mask to create a latent image in the radiation-sensitive coating that includes exposed and unexposed areas.

[0042] The amount of electromagnetic radiation can be characterized by a fluence or a dose, which is obtained by integrating the radiative flux over the exposure time. In some embodiments, a suitable radiation fluence is about 1 mJ / cm. 2~about 200mJ / cm 2 and in a further embodiment about 2 mJ / cm 2 ~Approx. 150mJ / cm 2 and in a further embodiment about 3 mJ / cm 2 ~about 100mJ / cm 2 In one embodiment, the EUV radiation is about 150 mJ / cm 2 or approximately 2 mC / cm at 30 kV. 2 This can be accomplished with the following doses of electron beam: A person of ordinary skill in the art will recognize that additional ranges of radiation fluence within the explicit ranges above are contemplated and are within the present disclosure.

[0043] Following exposure to radiation and formation of the latent image, a subsequent post-exposure bake (PEB) is typically performed. The timing of the PEB in the context of multi-patterning is discussed below. In some embodiments, the PEB can be performed in an ambient environment, and in additional embodiments, the PEB can be performed in the presence of a reactive gas such as HO, CO, CO, SO, or H, as described in U.S. Patent Application Serial No. 17 / 188,679 to Telecky et al., entitled "Process Environment For Inorganic Resist Patterning" (hereinafter the '679 application), which is incorporated herein by reference. In some embodiments, the PEB can be performed at a temperature of from about 45° C. to about 250° C., in additional embodiments from about 50° C. to about 190° C., and in further embodiments from about 60° C. to about 175° C. The post-exposure bake can generally be performed for at least about 0.1 minute, in further embodiments from about 0.5 minutes to about 30 minutes, and in additional embodiments from about 0.75 minutes to about 10 minutes. A person of ordinary skill in the art will recognize that additional ranges of PEB temperatures and times within the explicit ranges above are contemplated and are within the present disclosure. The PEB can be designed to further densify and / or strengthen the exposed areas without decomposing the unexposed areas into metal oxide.

[0044] After PEB, image development involves contacting the patterned coating material containing the latent image with a developer composition to remove either the non-irradiated coating material to form a negative image, or the irradiated coating to form a positive image; other organometallic patterning materials may or may not be suitable for both types of patterning. Using the organotin resist materials described herein, effective negative or positive patterning at the desired resolution can be achieved using an appropriate developer solution, generally based on the same coating formed from the same precursor composition; however, coating optimization may suggest some adjustment of the composition. In particular, the irradiated regions are at least partially condensed to enhance the metal oxide character, such that the irradiated material is resistant to dissolution by organic solvents, while the non-irradiated composition remains soluble in organic solvents. Reference to a condensed coating material refers to at least partial condensation in the sense of enhancing the oxide character of the material relative to the initial material. On the other hand, the non-irradiated material is not soluble in weak aqueous base or acid due to the hydrophobic nature of the material, so aqueous base can be used to remove the irradiated material while preserving the non-irradiated material for positive patterning.

[0045] For positive-tone imaging, suitable developers can generally be aqueous acids or bases. In some embodiments, aqueous bases can be used to obtain sharper images. To reduce developer contamination, it may be desirable to use developers that do not contain metal atoms. Therefore, quaternary ammonium hydroxide compositions, such as tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, or combinations thereof, are desirable positive-tone developers. Quaternary ammonium hydroxides of particular interest generally can be represented by the formula R4NOH, where R = methyl, ethyl, propyl, butyl, or combinations thereof. The coating materials described herein can generally be developed using the same developers currently commonly used for polymer resists, specifically tetramethylammonium hydroxide (TMAH). Commercially available TMAH is available at 2.38 wt %. Additionally, mixed quaternary tetraalkylammonium hydroxides can be used. Generally, the developer may contain from about 0.5 to about 30% by weight, and in further embodiments from about 1 to about 25% by weight, and in other embodiments from about 1.25 to about 20% by weight of a tetraalkylammonium hydroxide or similar quaternary ammonium hydroxide. A person of ordinary skill in the art will recognize that additional ranges of developer concentrations within the explicit ranges above are contemplated and are within the present disclosure.

[0046] For negative-tone imaging, the developer can be an organic solvent, such as the solvent used to form the precursor solution. Generally, the choice of developer can be influenced by the solubility parameters of both irradiated and non-irradiated coating materials, as well as the developer's volatility, flammability, toxicity, viscosity, and potential chemical interactions with other process materials. In particular, suitable developers include, for example, aromatic compounds (e.g., benzene, xylene, toluene), esters (e.g., propylene glycol monomethyl ester acetate (PGMEA), 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), ethers (e.g., tetrahydrofuran, dioxane, anisole), and the like. Improved developer compositions are described in U.S. Patent Application Publication No. 2020 / 0326627, entitled "Organometallic Photoresist Developer Compositions and Processing Methods," by Jiang et al., which is incorporated herein by reference. The improved developer solutions generally include a base organic solvent composition and an additive composition having higher polarity and / or hydrogen bonding properties than the base solvent composition. In one example, the improved developer composition may include PGMEA and acetic acid. Development may occur for about 5 seconds to about 30 minutes, in further embodiments from about 8 seconds to about 15 minutes, and in additional embodiments from about 10 seconds to about 10 minutes. A person of ordinary skill in the art will recognize that additional ranges within the explicit ranges above are contemplated and are within the scope of the present disclosure.

[0047] After development, it may be desirable to subject the newly formed resist pattern to a freeze step, such as a hard bake, to remove residual developer and improve the fidelity of the patterned lines. Such a post-development bake step can be used as a freeze step in the context of multi-patterning, as further described below. Generally, the hard bake conditions can be similar to those of the PEB step. In some embodiments, the hard bake can be performed in an ambient environment, and in additional embodiments, the PEB can be performed in the presence of a reactive gas such as HO, CO, CO, SO, H, or the like, as described in the above-cited '679 patent application. In some embodiments, the hard bake can be performed at a temperature of at least about 45°C, in some embodiments from about 45°C to about 400°C, in additional embodiments from about 50°C to about 300°C, and in further embodiments from about 60°C to about 250°C. The hard bake can generally be performed for at least about 0.1 minute, in further embodiments from about 0.5 minutes to about 30 minutes, and in additional embodiments from about 0.75 minutes to about 10 minutes. A person of ordinary skill in the art will recognize that additional ranges of PEB temperatures and times within the explicit ranges above are contemplated and are within the present disclosure. In some multiple-patterning process embodiments, it may be desirable to limit, avoid, or delay the post-development bake step to allow for further development of the initial pattern during subsequent patterning steps.

[0048] Multi-Patterning After forming an initial pattern of organometallic material on a surface, another layer of organometallic photoresist can be deposited on top of that pattern. Due to the processing advantages of organometallic patterning compositions, intervening processing steps are generally not used to separate the subsequent patterned resist from the previously patterned underlying layer. Due to chemical changes that occur during the exposure and / or PEB steps, the existing pattern of organometallic photoresist is insoluble in the coating composition. This property of the photoresist enables patterning approaches that would require more complex processing with traditional polymeric resists using methods known to those skilled in the art.

[0049] For example, double patterning using conventional resist requires transferring the resist pattern to another medium, for example, by using a litho-etch-litho-etch (LELE) process or a spacer-aligned patterning approach. In a typical LELE process, a first photoresist pattern is transferred to a hard mask layer, typically initially unpatterned, followed by a second lithography process to form a second photoresist pattern, and then a second etch to transfer the second pattern to the hard mask. By combining two smaller-pitch patterns, the final hard mask pattern can have a smaller pitch than the original photoresist pattern. In a typical spacer-aligned process, such as a spacer-aligned double patterning (SADP) process, a spacer material with a higher etch resistance than the photoresist material is conformally deposited on the initial photoresist pattern. Then, a series of etches are performed across the substrate, first removing portions of the spacer material so that only the sidewalls remain, and then stripping the remaining photoresist pattern to form a spacer material pattern with a smaller pitch than the initial resist pattern. Such processes require multiple processing steps to be performed, each adding cost, complexity, and the potential for defects.

[0050] The concept of multiple patterning herein generally involves sequential patterning steps with a selected relationship between subsequent patterns and a first pattern. These relationships are shown schematically in FIGS. 1A-1E. In FIG. 1A, a second pattern is developed to form features between the features of the first pattern, effectively reducing the feature spacing. As shown in this figure, the patterns are regularly spaced stripes. Referring to FIG. 1B, a second pattern overlaying a first pattern intersects with, and in this particular embodiment is orthogonal to, the first pattern. Each pattern depicted in FIG. 1B is again a series of regularly spaced stripes. Referring to FIG. 1C, a second pattern overlaying a first pattern has features diagonal to the first pattern, with both patterns having regularly spaced stripes. With respect to the multiple patterning structures of FIGS. 1A-1C, the stripes may be irregularly spaced or different shapes may be used for the stripes, within the feature size and spacing constraints of the patterning process. Referring to FIG. 1D, the second pattern has different characteristics from the first pattern, again some of which lie between features of the first pattern and some of which overlap features of the first pattern.

[0051] Figure 1E shows the cutting of the first pattern using a second patterning step. The cutting of the first pattern is guided by the second pattern. The cutting process can be effectively performed using reversed patterning at each step. After the cutting step, the second resist coating layer is completely stripped before further processing.

[0052] While the discussion herein focuses primarily on two patterning steps, a third or more patterning steps may be performed sequentially. These three or more patterning steps may be a simple generalization of the multiple patterning formats of FIGS. 1A-1E. The cutting step of FIG. 1E may be interposed between other multiple patterning steps or may be the final step in cutting one or more previous patterns to form the cut pattern. Dividing an entire target pattern into sequential patterns using multiple masks can be a complex procedure, and systematic approaches for dividing such masks are described, for example, in U.S. Pat. No. 9,679,095 to Li et al., entitled "Layout Decomposition for Multiple Patterning Lithography," and U.S. Patent Application Publication No. 2015 / 0040083 to Cheng et al., entitled "System and Method for Decomposition of a Single Photoresist Mask Pattern Into 3 Photoresist Mask Patterns," both of which are incorporated herein by reference.

[0053] The desirable processing approach described herein provides effective multi-patterning without intervening pattern transfer, based on high etch contrast and optimized pattern development. Therefore, multi-patterning can be performed using fewer steps than can be used for multi-patterning using organic resists. Generally, one or more underlying patterns are based on negative-tone patterning. The irradiated resist is maintained, while the unirradiated resist is removed by a developer. Subsequent layers or resists can then be deposited without the resist solvent damaging the initial pattern. After pattern development, a post-patterning freeze step, i.e., bake step, can optionally be performed to stabilize the pattern; such a freeze step will generally be desirable to improve overall patterning quality after multi-patterning steps. The cutting step can be performed using a positive-tone patterning step, such that the developer removes both the irradiated resist composition as well as the exposed portions of the previous pattern. Positive-tone patterning for cutting can be performed using an organic resist, which can be an organometallic patterning composition or a chemically amplified resist (CAR). The high pattern contrast makes this an affordable operation without pattern transfer.

[0054] Thus, for multiple patterning as depicted in Figures 1A-1D, the litho-freeze-litho-freeze (LFLF) process (where the freeze step is optional and / or adjustable) allows for a simpler processing scheme to achieve more complex, denser, or improved patterns compared to single patterning approaches, and a simpler processing scheme compared to other multiple patterning approaches available with conventional resists. In particularly interesting embodiments, the current process utilizes a hard mask on the substrate, which allows for greater flexibility without being constrained by substrate composition. During processing of complex structures, many layers of material can be deposited and patterned, allowing for variations in the composition of the top surface of the substrate at the start of the patterning process.

[0055] FIG. 2A shows a flowchart of the LFLF process. Referring to FIG. 2A, to begin the process, a substrate is obtained 10 and a hard mask layer is placed on the substrate 12. Two lithography processes are shown as parallel vertical arrays of steps. During the first lithography process, an organometallic photoresist is deposited on the substrate 14 using the methods described above. The resist then undergoes patterned radiation exposure 16 and development 18 to form an image or pattern from the latent image. To further stabilize the pattern, the structure can optionally be subjected to freezing 20, allowing for subsequent lithography steps while reducing damage to the original developed pattern. Freezing can be performed using the post-development bake step described above and / or an additional unpatterned UV exposure step. Post-development UV exposure can be used to break down remaining carbon-metal bonds and further stabilize the material against further processing. A blanket UV exposure step can be performed in the same tool without a mask. Subsequent lithography processes can then be performed without removing the developed pattern formed in the first lithography process.

[0056] The second lithography process similarly involves depositing 22 an organometallic photoresist over the frozen, developed pattern of the first lithography process, irradiating 24 the organometallic resist to form a second latent image, developing 26 the second latent image, and optionally performing a second hard bake freeze 28 to stabilize the second developed pattern. Further litho-freeze processes, such as those shown in the parallel set of steps in FIG. 2A, may be performed until the desired pattern of organometallic photoresist is obtained. Once patterning is complete, further processing 30 on the device can be performed. Simplifying the process to perform more than one lithography step can make device fabrication more efficient.

[0057] The cutting step is similar to the lithography step of FIG. 2, except that after the cutting step, unexposed resist is removed prior to an optional hard bake and further processing, either additional lithography steps or the next step in device formation. The cutting step is shown in FIG. 2B. After the previous patterning 32 is completed, an organometallic photoresist is deposited 34. The resist layer is then exposed to patterned radiation 36 to form a latent image. This latent image is developed into a positive resist 38. In the cutting process, development 38 can be effective to remove not only the irradiated resist, but also exposed areas of the underlying patterned resist formed from the irradiated resist by the previous lithography patterning step. Thus, process step 38 includes simultaneous development and cutting. Following development / cut 38, the unexposed resist is stripped 40. After stripping 40, an optional post-patterning bake 42 can be performed to stabilize the pattern. Additional processing can then be performed 30.

[0058] A double patterning process using "thermal freeze" is outlined in FIG. 3. The initial structure 50 includes a substrate 52 with a hard mask coating 54. The substrate 52 has an upper section 56 that can be subjected to processing and may or may not have its own distinct composition and / or patterning. In a first stage of processing 58, a first pattern 60 is formed on the hard mask 54. This patterning stage includes several steps as outlined in FIG. 2 in conjunction with the first column of steps for forming the first pattern. A second patterning stage 62 is then performed to form a second pattern 64 on the hard mask 54. FIG. 3 depicts a second pattern within the first pattern to form a higher-resolution overall pattern; the second pattern can be any of the types depicted in FIGS. 1A-1E. Additional patterning steps can be performed, and in the context of the overall process, the second pattern 64 can be considered the final pattern.

[0059] Once the second, or final, pattern 64 is formed, the pattern can be further processed 66 by transferring the entire pattern into hard mask 54 and stripping the remaining resist to form patterned hard mask 68. The hard mask pattern is then transferred to the upper section 56 of substrate 52. Pattern transfer to upper section 56 can include etching 70 to form etched substrate 72, or deposition 74 to form patterned hard mask 68 having a deposit 76, followed by a hard mask etch 78 to form patterned substrate 80.

[0060] It should be noted that this process can be readily extended to multiple coating and patterning steps, and such extensions are contemplated and within the scope of the present disclosure. With respect to multiple patterning, an important difference between the inorganic coating materials described herein and conventional organic resists is that the organic resists remain soluble in conventional resist casting solvents even after thermal baking. The resist materials described herein are not soluble in organic solvents and can be condensed upon thermal baking to allow subsequent coating layers to be applied.

[0061] Some examples of useful applications of the present invention include combining two different patterns that require different illumination conditions, such as combining a pillar pattern with a line-space pattern. Another advantage of the present invention is that it can provide the advantage of stitching desired patterns, allowing one portion of a desired pattern to be printed, followed by another portion of the pattern, to print a complete pattern that would otherwise be difficult to achieve in a single lithography step. Multiple exposure media can also be used for the present invention, using multiple exposure steps independently selected from exposure sources such as EUV, ArF, KrF, and e-beam, to combine each pattern into a new pattern that would otherwise be difficult or impossible to achieve using only one exposure source.

[0062] In some embodiments, adjacent linear segments of adjacent structures can have an average pitch (half pitch) of about 60 nm or less (30 nm half pitch), in some embodiments, about 50 nm or less (25 nm half pitch), and in further embodiments, about 34 nm or less (17 nm half pitch). Pitch can be assessed by design or confirmed with a scanning electron microscope (SEM), such as by top-down imaging. As used herein, pitch refers to the spatial period, or center-to-center distance, of repeating structural elements, and as commonly used in the art, half pitch is half the pitch. Dimensions of features of a pattern may also be described in terms of the average width of the feature, and are generally assessed away from corners, etc. Additionally, features can refer to gaps between and / or material elements. In some embodiments, the average width can be about 25 nm or less, in further embodiments, about 20 nm or less, and in additional embodiments, about 15 nm or less. A person of ordinary skill in the art will recognize that additional ranges of pitch and average width within the above explicit ranges are contemplated and are within the scope of the present disclosure.

[0063] In some embodiments, the average linewidth roughness can be about 5.5 nm or less, in some embodiments, about 5 nm or less, and in further embodiments, about 4.5 nm or less. As shown in the examples, linewidth roughness can be evaluated as a function of a critical dimension. Linewidth roughness is evaluated by analyzing top-down SEM images to derive the 3σ deviation from the average linewidth. The average value includes both high-frequency and low-frequency roughness, i.e., short correlation lengths and long correlation lengths, respectively. While the linewidth roughness of organic resists can be characterized primarily by long correlation lengths, the present organometallic coating materials exhibit significantly shorter correlation lengths. In pattern transfer processes, short correlation roughness can be smoothed during the etching process, resulting in higher pattern fidelity. One of ordinary skill in the art will recognize that additional ranges of linewidth roughness within the explicit ranges above are contemplated and are within the scope of the present disclosure. Rinsing can be performed to further remove some patterning defects and improve pattern fidelity, as described in U.S. Patent Application Publication No. 2020 / 0124970 to Kocsis et al., entitled "Patterned Organometallic Photoresists and Methods of Patterning," which is incorporated herein by reference.

[0064] After the desired pattern is formed using the methods herein, the resulting structure can be further processed as desired to achieve a functional integrated circuit.

[0065] Specific Multi-Patterning Embodiments In general, metalorganic patterning resists provide a useful platform for effective multi-patterning with reduced process steps and good ability to utilize EUV processing. This section describes three multi-patterning scenarios in more detail with appropriate figures, and more specifically describes representative embodiments of these multi-patterning scenarios. First, a litho-freeze-litho-freeze process is described, in which successive negative-tone patterning is performed, typically with a thermal freeze step between two patterning steps. While the freeze step is optional, it is generally desirable. Second, a litho(negative)-litho(positive / cut)-partial release-freeze process is described, in which a portion of the first pattern is cut simultaneously with positive-tone development. Freezing can optionally be performed after the first litho step. The partial release step removes the remaining resist from the positive-tone patterning after the cut step is complete, leaving the uncut remainder of the first pattern formed by the negative-tone processing. In the third process step group, a pattern-pattern-lithography process is performed in which the radiation-sensitive coating is exposed to two different mask patterns to form a composite latent image, followed by a development step, which then develops to form a composite pattern. These processes can also be combined as appropriate, as further described after the description of the figures.

[0066] 4-15 relate to a litho-freeze-litho-freeze process in which features from a second lithography process are positioned within the pattern of the first lithography process. After exposure to radiation, the first photosensitive organometallic material is patterned, including irradiated and non-irradiated regions. Referring to FIGS. 4 and 5, a patterned structure 100 is shown, comprising a substrate 102, a hard mask layer 103, and a patterned organometallic material 104. The patterned organometallic material 104 comprises condensed regions 110, 112, 116 of the irradiated coating material and non-condensed regions 118, 120 of the non-irradiated coating material. The pattern formed by the condensed regions 110, 112, 116 and the non-condensed regions 118, 120 represents a latent image in the organometallic material, the development of which is described in the following sections. Suitable materials for each of these layers have been described in detail above, and the above discussion may be considered to be reproduced here in its entirety.

[0067] 6 and 7, the latent image of the structure shown in FIGS. 4 and 5 is developed through contact with a developer to form patterned structure 130. Developer compositions for negative tone development are described in detail above, and that discussion can be considered part of this discussion. After development of the image, hard mask layer 103 is exposed along its top surface through openings 132 and 134. Openings 132 and 134 are located at the locations of non-condensed regions 118 and 120, respectively.

[0068] After post-development hard-bake heating of the patterned structure 130, the pattern of metalorganic material is chemically “frozen” and therefore more insoluble and stable in subsequent negative lithography processes. Referring to Figures 8 and 9, a patterned structure 160 is shown, comprising a substrate 102, a hard mask layer 103, “frozen” metalorganic materials 162, 164, and 166, and a second metalorganic material 170 deposited using the solution deposition and / or vapor deposition approaches described above. The pattern formed by the “frozen” regions 162, 164, and 166 is preserved under the second metalorganic material 170, regardless of the deposition approach, because the frozen regions are not soluble in the solvent used to deposit the metalorganic material. While a post-development bake to freeze the pattern is generally not required, it is an efficient process to improve the pattern structure and further stabilize the structure.

[0069] After exposure to radiation, the second photosensitive organometallic material is patterned, including irradiated and unirradiated regions. Referring to Figures 10 and 11, a patterned structure 190 is shown, comprising substrate 102, hard mask layer 103, the "frozen" previous pattern of organometallic materials 162, 164, and 166, and patterned organometallic material 180. The patterned organometallic material 180 comprises regions 198 and 200 of irradiated coating material and non-condensed regions 192, 194, and 196 of unirradiated coating material. The pattern formed by the condensed regions 198 and 200 is parallel to and offset from the pattern formed by the "frozen" organometallic materials 162, 164, and 166. The pattern formed by the condensed regions 198 and 200 and non-irradiated regions 192, 194, and 196 represents a latent image in the second organometallic material. This pattern is referred to as the second latent image.

[0070] 12 and 13, a second latent image of the structure shown in Figures 10 and 11 is developed through contact with a negative-tone developer to form double-patterned line structure 220. After development of the second latent image, organometallic materials 232 and 234 are located at the locations of condensed regions 198 and 200, respectively. "Frozen" organometallic materials 162, 164, and 166 are located at the locations of condensed regions 110, 112, and 116, respectively. Hard mask layer 103 is exposed along its top surface through openings 222, 224, 226, and 228.

[0071] 14 and 15, the etched hard mask 274 exposes the substrate 102 along its top surface through openings 264, 266, 268, and 270. The patterned substrate 250 consists of hard mask regions 252, 254, 256, 258, and 262. The hard mask regions 252, 254, 256, 258, and 262 correspond to the locations of the organometallic materials 232 and 234 and the "frozen" organometallic materials 162, 164, and 166 shown in FIGS. 9 and 10, respectively. Further processing of the patterned substrate 250 may include etching the substrate 102 through the openings 264, 266, 268, and 270, as depicted in FIG. 3, for example. Alternatively, or additionally, deposits can be applied to the substrate through the openings 264, 266, 268, and 270, which can be performed whether or not the substrate is first etched.

[0072] 16-21 relate to a litho-freeze-litho-freeze process in which features from a second lithography step lie perpendicularly on top of the pattern from a first lithography step. FIG. 16 illustrates the exposure of patterned structure 160 (FIGS. 8 and 9) to radiation to pattern a second photosensitive organometallic material having irradiated and non-irradiated regions. The resulting patterned structure 280 is shown, comprising substrate 102, hard mask layer 103, "frozen" organometallic materials 162, 164, and 166, and patterned organometallic material 282. Patterned organometallic material 282 comprises condensed regions 290, 292, and 294 of irradiated coating material and regions 284, 286, and 288 of non-irradiated coating material. The pattern formed by condensed regions 290, 292, and 294 is perpendicular to the pattern formed by "frozen" organometallic materials 162, 164, and 166. The pattern formed by condensed regions 290, 292, 294 and unexposed regions 284, 286, 288 represents a latent image in the second organometallic material. This pattern is referred to as the second latent image. Referring to Figures 18 and 19A-19C, the second latent image of the structure shown in Figures 16 and 17 is developed through contact with a negative-tone developer to form a crosshatched patterned structure 310. After development of the second latent image, organometallic materials 312, 314, and 316 are located at the positions of condensed regions 290, 292, and 294, respectively. Portions of organometallic materials 312, 314, and 316 are adjacent to, but do not cut through, the "frozen" organometallic materials 162, 164, and 166. The "frozen" organometallic materials 162, 164, and 166 are located at the positions of condensed regions 110, 112, and 116, respectively. The hard mask layer 103 is exposed along its top surface through openings 324, 326, 328, 330, 332, and 334.

[0073] After hard-baking the crosshatch-patterned structure 310, the metalorganic material pattern is chemically "frozen" and therefore more insoluble and stable for subsequent processing. Referring to Figures 20 and 21, a patterned substrate 340 is comprised of a patterned hard mask 342 having a pattern corresponding to the locations of the metalorganic materials 312, 314, and 316 and "frozen" metalorganic materials 162, 164, and 166 shown in Figures 18 and 19A-19C. The patterned hard mask 342 exposes the substrate 102 along its top surface through openings 344, 346, 348, 350, 352, and 354. Further processing of the patterned substrate 340 may include etching the substrate 102 through the openings 344, 346, 348, 350, 352, and 354, as depicted in Figure 3, for example. Alternatively, or additionally, the deposits can be delivered to the substrate through the openings 344, 346, 348, 350, 352, 354, and this can be done with or without first etching the substrate.

[0074] 22A-22F relate to a litho-lithography process in which features from a second lithography step cut features from a first lithography step by using a negative-tone patterning step followed by positive-tone patterning. FIGS. 22A and 22B show a patterned structure including a metalorganic material 360 patterned in a hard mask layer 362. Typically, the hard mask layer 362 resides on a substrate 102. The metalorganic material 360 is a first photosensitive metalorganic material that has been irradiated and at least partially condensed, but may not have been subjected to a hard bake freeze. While a hard bake freeze step can stabilize the structure of FIG. 22A, the hard bake freeze can delay subsequent development to cut the structure. The metalorganic material 360 is developed through contact with a negative developer to form a pattern. In Figures 22C and 22D, a second photosensitive organometallic material 364 is deposited on the patterned structure of Figures 22A and 22B using the solution deposition and / or vapor deposition approaches described above and patterned using radiation to form a latent image with irradiated regions 366. In some embodiments, the first and second photosensitive organometallic materials may be the same material. Referring to Figure 22E, the irradiated regions 366 are developed using a positive tone developer to form open regions 370. The positive tone developer also removes the exposed organometallic material 360 in the same development step. With both the irradiated second photosensitive organometallic material and the exposed organometallic material 360 removed, the open regions 370 expose the hard mask layer 362. Referring to Figure 22F, the unexposed second organometallic material 364 is stripped, revealing the patterned resist 376 on the hard mask layer 362. Cuts 374 through patterned resist 376 correspond to open areas 370. Further processing of the patterned structure of Figure 22D typically involves etching through hard mask layer 362 to expose portions of the substrate underlying hard mask layer 362. The remaining patterned organometallic material can then be stripped.

[0075] Figures 23A-23D relate to a litho-litho-etch process in which latent features from a second irradiation step are added to the latent features from a first lithography step and then developed in a single step to form a pattern of organometallic material. Figure 23A shows a patterned structure with condensed regions 380 of irradiated organometallic material and regions 382 of unirradiated organometallic material. The pattern formed by condensed regions 380 and unirradiated regions 382 represents a latent image in the organometallic material. This pattern is referred to as the first latent image. Figure 23B shows the patterned structure of Figure 23A after being irradiated to form condensed regions 384 of irradiated organometallic material. The pattern formed by condensed regions 380, 384, and unirradiated regions 385 represents a latent image in the organometallic material. This pattern is referred to as the composite latent image. Referring to FIG. 23C, the composite latent image of the structure shown in FIG. 23B is developed through contact with a negative developer to remove the unexposed organometallic material from the unexposed areas 385, forming the patterned structure of FIG. 23C. The patterned structure of FIG. 23C includes a patterned organometallic material 388 on a hard mask layer 386. Referring to FIG. 23D, after etching the hard mask layer 386 according to the patterned structure of FIG. 23C, the etched hard mask 394 exposes the substrate 390 along its top surface. The etched hard mask 394 corresponds to the location of the patterned organometallic material 388. Typically, the patterned organometallic material 388 is stripped prior to further processing. Further processing of the patterned structure of FIG. 23D may include etching the substrate 390, for example, as depicted in FIG. 3. Alternatively, or additionally, the deposit can be applied to the substrate 390 through openings formed by the etched hard mask 394, and this can be done with or without first etching the substrate.

[0076] Figures 24A-24D illustrate a litho-litho-etch process similar to the previous process, but using a positive developer instead of a negative developer. Figure 24A shows a patterned structure with condensed regions 394 of irradiated organometallic material and regions 396 of unirradiated organometallic material. The pattern formed by irradiated regions 394 and unirradiated regions 396 represents a latent image in the organometallic material. This pattern is referred to as the first latent image. Figure 24B shows the patterned structure of Figure 24A after being irradiated to form irradiated regions 398 of irradiated organometallic material. The pattern formed by irradiated regions 394, irradiated regions 398, and unirradiated regions 397 represents a latent image in the organometallic material. This pattern is referred to as the composite latent image. Referring to FIG. 24C, the composite latent image of the structure shown in FIG. 24B is developed through contact with a developer for a positive image, removing the irradiated organometallic material from irradiated areas 394 and 398, forming the patterned structure of FIG. 24C. The patterned structure of FIG. 24C includes a patterned organometallic material 400 on a hard mask layer 402. Referring to FIG. 24D, after etching the hard mask layer 402 according to the patterned structure of FIG. 24C, the etched hard mask 404 exposes the substrate 406 along its top surface. The etched hard mask 404 corresponds to the location of the patterned organometallic material 400. Typically, the patterned organometallic material 388 is stripped before further processing. Further processing of the patterned structure of FIG. 24D may include etching the substrate 406, for example, as depicted in FIG. 3. Alternatively, or additionally, the deposit can be delivered to the substrate 406 through openings formed by the etched hard mask 404, and this can be done with or without first etching the substrate.

[0077] The various multi-patterning processes depicted in Figures 1-24D can be combined in any suitable manner, generally as described above. The following example describes a method for performing LFLF on organo-tin resist using EUV lithography.

[0078] The multi-patterning processes described herein can produce rectangular holes having an average size of about 50 nm or less, in further embodiments 40 nm or less, in other embodiments 30 nm or less, and in additional embodiments 20 nm to 30 nm. Size refers to the diameter or diagonal length for rectangular holes, and one of ordinary skill in the art can assess appropriate sizes for other shapes based on this information. One of ordinary skill in the art will recognize that other ranges of hole sizes within the explicit ranges are contemplated and are within the scope of the present disclosure. [Example]

[0079] Example: Double patterning contact holes This example demonstrates a method of double patterning using organotin photoresist in which a first layer of photosensitive organotin material is patterned on a substrate, and then a subsequent layer of photosensitive organotin material is deposited on top of the first patterned layer and patterned perpendicular to the first pattern, resulting in a crosshatch type pattern.

[0080] The substrate in this example consisted of a Si wafer coated with 10 nm of spin-on glass (SOG) as an underlayer, although the identity of the underlayer is not critical to the practice of this method. Other underlayers may be used as long as they provide adequate adhesion and sufficient lithographic performance. The organotin resist used in this example was YATU1011, manufactured by Inpria Corporation and having a composition described in U.S. Pat. No. 10,228,618 to Meyers et al., entitled "Organotin Oxide Hydroxide Patterning Composition, Precursors, and Patterning."

[0081] The first organotin layer was deposited by spin coating at 1394 rpm to form a film approximately 22 nm thick, followed by a post-apply bake (PAB) step at 100°C for 60 seconds. After the PAB step, the wafer was exposed to EUV radiation in an ASML NXE3300 scanner to form the first radiation patterning layer. After exposure, a post-exposure bake (PEB) was performed at 170°C for 60 seconds. The first patterning layer was then developed and subjected to a hard bake at 250°C for 60 seconds, producing a first pattern consisting of parallel 16.0 nm lines with a 32.0 nm pitch in the patterned substrate. This hard bake is used to "freeze" the pattern, i.e., to make it completely insoluble in subsequent lithography processes.

[0082] After fabricating the first patterned substrate, a second layer of organotin material can be deposited on the patterned substrate and subjected to PAB using the same process and conditions employed to form the first organotin layer. The wafer was then rotated 90° and exposed to EUV radiation in an ASML NXE3300 scanner. Because the wafer is rotated 90° relative to the first pattern, the second exposure produces an irradiation pattern perpendicular to the first. After exposure, the wafer was subjected to PEB at 170°C for 60 seconds, developed, and hard baked at 250°C for 60 seconds to form a double-patterned substrate. Figure 25 shows a CD-SEM image of the final product. A crosshatched pattern is observed, with the first patterning step forming lines in the x-direction and the second patterning step forming lines in the y-direction. This crosshatch pattern has 16.0 nm organotin material lines with a 32.0 nm pitch and a linewidth roughness of 1.8 nm, forming approximately 16.6 nm square holes. This structure is useful as a method for fabricating contact holes.

[0083] In both lithography processes, the developer composition contained PGME and acetic acid, as described in U.S. patent application Ser. No. 16 / 845,511 by Jiang et al., entitled "Organometallic Photoresist Developer Compositions." Other developers, such as 2-heptanone, and others, such as those described in U.S. Patent No. 9,310,684, entitled "Organometallic Solution Based High Resolution Patterning Compositions," and U.S. Patent No. 10,228,618, entitled "Organotin Oxide Hydroxide Patterning Composition, Precursors, And Patterning," by Meyers et al., may also be used.

[0084] The above embodiments are intended to be illustrative and not limiting. Additional embodiments are within the scope of the claims. Moreover, while the present invention has been described with reference to specific embodiments, those skilled in the art will recognize that changes in form and detail can be made without departing from the spirit and scope of the present invention. Any incorporation by reference of the above documents is limited such that no subject matter contrary to the explicit disclosure herein is incorporated. Unless otherwise specified, to the extent that a particular structure, composition, and / or process is described herein with components, elements, ingredients, or other classes, as suggested in the discussion, the disclosure herein should be understood to encompass specific embodiments, embodiments that include specific components, elements, ingredients, other classes, or combinations thereof, as well as embodiments that consist essentially of such specific components, ingredients, ingredients, other classes, or combinations thereof, which may include additional features that do not alter the fundamental nature of the subject matter. The use of the word "about" herein refers to the degree of error in measurement of the particular parameter, unless expressly stated otherwise, as would be understood by one of ordinary skill in the art based on the teachings herein.

Claims

1. 1. A method of patterning a substrate, comprising: irradiating a layer of a photosensitive composition over a patterned substructure to form a latent image, the photosensitive composition comprising an organometallic composition having a radiation-sensitive ligand bonded to a metal, the patterned substructure comprising, in order, a substrate, an unpatterned hard mask layer on the substrate, and a patterned metal oxide-based material having a first pattern on the hard mask layer, the photosensitive composition being located on the hard mask layer together with the patterned metal oxide-based material, the pattern corresponding to the latent image being different from the first pattern, and the hard mask layer having a differential etch with respect to the irradiated photosensitive composition and the patterned metal oxide-based material; developing the latent image to form a second pattern from the irradiated photosensitive composition to form a developed structure; A method comprising:

2. the patterned metal oxide-based material is formed by irradiating a first layer comprising a first photosensitive organometallic material on a surface of the hard mask according to a first selected pattern, the first photosensitive organometallic material comprising a radiation-sensitive ligand bonded to a metal; 10. The method of claim 1, wherein the irradiated first layer is contacted with a developer composition to remove non-irradiated portions of the irradiated first layer and form the patterned metal oxide-based material.

3. 3. The method of claim 2, further comprising heating the patterned metal oxide-based material to a temperature of at least 45° C. for about 0.5 minutes to about 30 minutes before forming the layer of photosensitive material.

4. The method of claim 2 or 3, wherein the first layer has a thickness of about 1 nm to about 100 nm.

5. The method of any one of claims 1 to 4, wherein the patterned metal oxide-based material is not soluble in organic solvents.

6. 6. The method of any one of claims 1 to 5, wherein the layer of photosensitive composition is formed by depositing a precursor composition, and the depositing comprises vapor deposition, spin coating, spray coating, or dip coating.

7. The method of any one of claims 1 to 6, wherein the layer of photosensitive composition has a thickness of from about 1 nm to about 50 nm.

8. The irradiation is about 1 mJ / cm ２ ~Approx. 200mJ / cm ２ or about 2 mC / cm at about 30 kV. ２ 8. The method of any one of claims 1 to 7, comprising an electron beam at a dose of:

9. The method of any one of claims 1 to 8, wherein the developing comprises an organic solvent.

10. 10. The method of claim 1, wherein the first pattern comprises a line-space pattern, a pillar pattern, or a combination thereof, and the projection of a pattern corresponding to the latent image overlaps with the first pattern, is located within the first pattern, or is a combination thereof.

11. heating and / or irradiating the developed structure to condense the irradiated photosensitive composition and form a composite pattern suitable for patterning the hard mask; Etching the hard mask based on the composite pattern or a portion thereof to form a patterned hard mask; removing the irradiated photosensitive composition and the patterned metal oxide-based composition to expose the patterned hard mask layer; The method of any one of claims 1 to 10, further comprising:

12. 12. The method of claim 11, wherein the heating is carried out at a temperature of at least 45°C for a period of about 30 minutes or less.

13. 13. The method of claim 11 or 12, further comprising etching the substrate and / or depositing a fill material onto the substrate based on the exposed patterned hard mask layer.

14. a substrate; an unpatterned hard mask coating on the substrate; a first pattern of a first tin oxide based material on the hard mask coating, wherein gaps in the first pattern do not cover the hard mask; a second pattern of a second tin oxide based material on the hard mask coating including the first pattern; and wherein the second pattern is different from the first pattern, provided that the second pattern does not overlap the first pattern, and the linewidth roughness of the first pattern is less than ¼ of the inter-feature distance of the first pattern.

15. 15. The structure of claim 14, wherein the first pattern and / or the second pattern comprises a line-space pattern, a pillar pattern, or a combination thereof, and the second pattern overlaps the first pattern, is located within the first pattern, or has a portion overlapping the first pattern and a portion within the first pattern.

16. the first pattern and the second pattern form a hybrid pattern including a crosshatch pattern of holes, the holes exposing the unpatterned hard mask coating, the holes having an average size of about 30 nm or less; or 15. The structure of claim 14, wherein the first pattern and the second pattern form a hybrid pattern including a line-space pattern, the line-space pattern having an average pitch of about 60 nm or less.

17. The structure of any one of claims 14 to 16, wherein the first tin oxide based material and the second tin oxide based material have the same composition.

18. The structure of any one of claims 14 to 17, wherein the first tin oxide based material and the second tin oxide based material comprise an organometallic oxide / hydroxide network.

19. The organometallic oxide / hydroxide network has the formula R ｚ SnO （２－（ｚ／２）－（ｘ／２）） (OH) ｘ 19. The structure of claim 18, represented by the formula: wherein 0<z≦2 and 0<(z+x)≦4, R comprises a hydrocarbyl group or blend thereof having 1 to 31 carbon atoms, and R forms a carbon-tin bond.

20. 1. A method of forming a patterned structure using radiation-based lithography, comprising: A method comprising carrying out a positive tone development process on a latent image formed in a patterning composition deposited on a patterned metal composition supported by a structure, wherein the positive tone development process removes the irradiated portion of the latent image in the patterning composition and the exposed portion of the patterned metal composition to form a cut pattern in the patterned metal composition.

21. The patterned composition is formed by irradiating a first layer comprising a first organometallic material on a surface of the structure according to a first selected pattern; 21. The method of claim 20, wherein the irradiated first layer is contacted with a developing composition to remove non-irradiated material.

22. 22. The method of claim 21, wherein the patterning composition and the first organometallic material are formed from the same precursor composition.

23. stripping the patterning composition; heating and / or irradiating the patterned structure to further condense the patterned metal composition; Etching the hard mask based on a cut pattern or a portion thereof to form a patterned structure; removing the patterned metal composition to expose the patterned structure; The method of any one of claims 20 to 22, further comprising:

24. 1. A method of forming a patterned structure, comprising: irradiating a structure including the layer of organometallic radiation-sensitive material and the substrate according to a first pattern to form a first latent image; further irradiating the structure containing the first latent image according to a second pattern to form the second latent image superimposed on the first latent image, wherein the first latent image and the superimposed second latent image form a composite latent image; developing the structure containing the composite latent image to form the patterned structure; A method comprising:

25. 25. The method of claim 24, wherein said developing comprises a negative tone developer.

26. 25. The method of claim 24, wherein said developing comprises a positive tone developer.

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