In-resist process for high-density contact formation

Abstract

A microfabrication method comprises the steps of forming a first relief pattern on a target layer of a substrate, coating the first relief pattern with a first solubility converter, stacking a first polymer filler on the first relief pattern, and diffusing the first solubility converter into the first polymer filler to provide a solubility-converted region of the first polymer filler. Subsequently, the method comprises the steps of forming a second relief pattern on the first relief pattern, coating the second relief pattern with a second solubility converter, stacking a second polymer filler on the second relief pattern, and diffusing the second solubility converter into the second polymer filler to provide a solubility-converted region of the second polymer filler. Finally, the solubility-converted regions of the first polymer filler and the second polymer filler are developed so that the target layer is etched.

Description

Technology Field

[0001] The present invention relates to an in-resist process for forming high-density contacts. Background Technology

[0002] Multi-patterning is a term describing the use of more than one lithography step to create a final pattern. Various forms of multi-patterning have enabled the production of advanced semiconductor devices. Patterning generally involves two basic steps. The first step involves creating a pattern using mask-based light exposure via lithography and then developing the available regions. The second step involves transferring the pattern to the base material through directional or anisotropic etching. These two steps together can be referred to as device patterning.

[0003] High-density contact arrays define the characteristics of dynamic access random memory (DRAM) and static random-access memory (SRAM) technologies and are important for advanced logic. Conventional multi-patterning processes can form contact arrays by intersecting the planes of sidewall spacers. However, processing sidewall spacers is relatively costly and time-consuming due to the necessary vapor deposition and etching.

[0004] This summary is provided to introduce a selection of concepts further described in the detailed description below. This summary is not intended to identify the core or essential features of the claimed subject matter, nor is it intended to help limit the scope of the claimed subject matter.

[0005] In one embodiment, the embodiment disclosed herein relates to a microfabrication method comprising the steps of providing a substrate on which a target layer is formed, forming a first relief pattern on the substrate, coating the first relief pattern with a first solubility converting agent, and depositing a first polymer filler on the first relief pattern. Subsequently, the method comprises the step of diffusing the first solubility converting agent into the first polymer filler at a predetermined distance to provide a solubility-converted region of the first polymer filler, wherein the solubility-converted region of the first polymer filler is in contact with the first relief pattern and the solubility-converted region of the first polymer filler is soluble in the first developer. Subsequently, a second relief pattern is formed on the first relief pattern and coated with a second solubility converting agent. Subsequently, the method comprises the steps of: depositing a second polymer filler on a second relief pattern; diffusing a second solubility converting agent into the second polymer filler by a predetermined distance to provide a solubility converted region of the second polymer filler, wherein the solubility converted region of the second polymer filler is in contact with the second relief pattern and the solubility converted region of the second polymer filler is soluble in the second developer. Finally, the method comprises the steps of: developing the first polymer filler and the second polymer filler so that the solubility converted region of the first polymer filler and the solubility converted region of the second polymer filler dissolve to provide a gap between the first relief pattern, the first polymer filler, the second relief pattern, and the second polymer filler, wherein a portion of the target layer is exposed; and etching the target layer using the first relief pattern, the first polymer filler, the second relief pattern, and the second polymer filler as a combined etching mask.

[0006] In another aspect, the embodiment disclosed herein relates to a microfabrication method comprising the steps of providing a substrate having a target layer formed thereon, forming a first relief pattern on the substrate, coating the first relief pattern with a first solubility converting agent, stacking a first polymer filler on the first relief pattern, and diffusing the first solubility converting agent into the first polymer filler by a predetermined distance to provide a solubility-converted region of the first polymer filler, wherein the solubility-converted region of the first polymer filler is in contact with the first relief pattern. Subsequently, the method comprises the step of developing the first polymer filler so that the solubility-converted region of the first polymer filler dissolves to provide a gap between the first relief pattern and the first polymer filler, wherein a portion of the target layer is exposed, and the step of etching the target layer using the first relief pattern and the first polymer filler as a combined etching mask. The method further comprises the steps of forming a second relief pattern on a substrate, coating the second relief pattern with a second solubility converting agent, stacking a second polymer filler on the second relief pattern, and diffusing the second solubility converting agent into the second polymer filler by a predetermined distance to provide a solubility-converted region of the second polymer filler, wherein the solubility-converted region of the second polymer filler is in contact with the second relief pattern. Finally, the method comprises the step of developing the second polymer filler so that the solubility-converted region of the second polymer filler dissolves to provide a gap between the second relief pattern and the second polymer filler, wherein a portion of the target layer is exposed, and etching the target layer of the substrate using the second relief pattern and the second polymer filler as a combined etching mask.

[0007] Other aspects and advantages of the claimed subject matter will become apparent from the following description and the appended claims. Brief explanation of the drawing

[0008] FIG. 1 is a block flowchart of a method according to one or more embodiments of the present disclosure. FIGS. 2a to 2i are schematic examples of substrates coated at each point of a method according to one or more embodiments of the present disclosure. FIG. 3 is a block flowchart of a method according to one or more embodiments of the present disclosure. FIG. 4 is an exemplary schematic diagram of a pattern generated using a method according to one or more embodiments of the present disclosure. Specific details for implementing the invention

[0009] The present disclosure generally relates to a method for multi-patterning a semiconductor substrate. In one or more embodiments, the method comprises the step of forming a complex pattern, such as a high-density array of holes or openings, on a substrate. As used herein, the terms “semiconductor substrate” and “substrate” are used interchangeably and may be any semiconductor material, including but not limited to semiconductor wafers, semiconductor material layers, and combinations thereof. The method may comprise the step of directly cutting the complex pattern on the substrate.

[0010] The method disclosed herein eliminates the need for sidewall spacers by intersecting two planes of an anti-spacer pattern to define a contact array. Typically, the anti-spacer process is an in-track process (i.e., performed in a coater-developer tool) that generates spacers using chemical process diffusion with a single exposure. In the method according to the present disclosure, two or three anti-spacer processes may be used to generate a high-density contact array. This method can advantageously generate very small contacts at a much lower cost and guaranteed size.

[0011] A method (100) for applying two spacer prevention processes to pattern a substrate according to the present disclosure is illustrated in FIG. 1 and is discussed with reference thereto. First, the method (100) includes the step of providing a substrate in block (102) on which a target layer is formed. Subsequently, in block (104), a first relief pattern may be formed on the target layer. The first relief pattern may be formed using a photolithography process and may be manufactured with a first resist. In block (106), the first relief pattern is coated with a first solubility converter. In a specific embodiment, the first solubility converter is formulated together with the first resist. When a solubility modifier is formulated together with a first resist, the solubility modifier, which is a thermal acid generator, can be added to the first resist having an activation temperature higher than the temperature at which the resist is processed in the absence of a thermal acid generator, so that the solubility modifier is activated after the photolithography process to form a first relief pattern. The generated acid can diffuse out of the first resist and modify the solubility of the second resist. Subsequently, in block (108), a first polymer filler is laminated onto the substrate so that any exposed portion of the target layer is covered with the first polymer filler. The lamination of the first polymer filler may also be referred to as "planarizing" the substrate, as this step can provide a flat layer on top of the substrate. In block (110), the first solubility modifier then diffuses into the first polymer filler to provide a solubility-modified region of the first polymer filler that is soluble in the first developer.

[0012] In block (112) of the method (100), a second relief pattern may be formed on the first relief pattern and the first polymer filler. The second relief pattern may be formed using a photolithography process and may be manufactured with a second resist. In one or more embodiments, the second relief pattern is formed orthogonally to the first relief pattern. In block (114), the second relief pattern is coated with a second solubility converter. Subsequently, in block (116), the second polymer filler is laminated onto the second relief pattern to fill any gap in the second relief pattern that exposes the first relief pattern, the first polymer filler, or the target layer. In block (118), the second solubility converter diffuses into the second polymer filler to provide a solubility-converted region of the second polymer filler that is soluble in the second developer. In block (120), the first and second polymer fillers are developed. In block (122), after developing the upper plane, the target layer can be etched to form a pattern of a high-density contact array.

[0013] Schematic diagrams of substrates coated at various points during the method described above are illustrated in FIGS. 2a through 2i. In the same invention, "coated substrate" refers to a substrate coated with one or more layers, such as a first resist layer and a first polymer filler layer. FIG. 2a illustrates a substrate comprising a target layer and a first relief pattern. FIG. 2b illustrates a substrate comprising a first relief pattern coated with a first solubility converter. In FIG. 2c, the first polymer filler is laminated over the target layer and the first relief pattern. FIG. 2d illustrates a coated substrate having a solubility-converted region of the first polymer filler, provided that the solubility converter is diffused into the first polymer filler. Now, switching to a top view, FIG. 2e illustrates a second relief pattern laminated over the first polymer filler, and FIG. 2f illustrates a second relief pattern coated with a second solubility converter. In FIG. 2g, the second polymer filler is laminated over the second relief pattern. FIG. 2h illustrates a coated substrate providing a second polymer filler having a solubility-converted region after the second solubility-converting agent diffuses into the second polymer filler. Finally, FIG. 2i illustrates a coated substrate after the first and second polymer fillers are developed, thereby exposing a portion of the target layer so that it can be etched. The method of FIG. 1 and the coated substrates illustrated in FIG. 2a through 2i are discussed in more detail below.

[0014] In block (102) of the method (100), a target layer is provided on a substrate. The target layer may be any target or memory layer known in the art. In one or more specific embodiments, the target layer is a hard mask layer.

[0015] Next, in block (104), a first relief pattern is provided. FIG. 2a illustrates an example of a first relief pattern (204) on a target layer (202) of a substrate (201). As illustrated in FIG. 2a, the first relief pattern may include features separated by a gap. A portion of the substrate may be exposed due to the presence of the gap in the first relief pattern. The features of the first relief pattern may be made of a first resist (203). The first resist may be a photoresist. Generally, a photoresist is a chemically amplified photosensitive composition comprising a polymer, a photogenerative agent, and a solvent. In one or more embodiments, the first resist comprises a polymer. The polymer may be any standard polymer commonly used in resist materials, and in particular may be a polymer having acid-labile groups. For example, the polymer may be a polymer prepared from monomers comprising styrene, p-hydroxystyrene, acrylates, methacrylates, norbornene, and combinations thereof. Monomers containing reactive functional groups may be present in the polymer in a protected form. For example, the -OH group of p-hydroxystyrene may be protected by a tert-butyloxycarbonyl protecting group. Such protecting groups may alter the reactivity and solubility of the polymer contained in the first resist. As understood by those skilled in the art, various protecting groups may be used for this reason. Acid-unstable groups include, for example, the following: a tertiary alkyl ester group, a secondary or tertiary aryl ester group, a secondary or tertiary ester group having a combination of alkyl and aryl groups, a tertiary alkoxy group, an acetal group, or a ketal group.Acid-unstable groups are also commonly referred to in the industry as "acid-decomposable groups," "acid-cleavable groups," "acid-cleavable protecting groups," "acid-labile protecting groups," "acid-leaving groups," and "acid-sensitive groups."

[0016] The acid-unstable group that forms a carboxylic acid on the polymer upon decomposition is preferably of the general formula ―C(O)OC(R 1 )3's tertiary ester group or general formula ―C(O)OC(R 2 )2OR 3 It is the acetal group of, and in the above formula: R 1 Each independently

[0017] Linear C 1-20　 Alkyl, branched C 3-20　 Alkyl, monocyclic, or polycyclic C 3-20　 Cycloalkyl, linear C 2-20　 Alkenyl, branched C 3-20　 Alkenyl, monocyclic, or polycyclic C 3-20　 Cycloalkenyl, monocyclic or polycyclic C 6-20　 Aryl, or monocyclic or polycyclic C 2-20　 Heteroaryl, preferably linear C 1-6　 Alkyl, branched C 3-6　 Alkyl, or monocyclic or polycyclic C 3-10　 They are cycloalkyl, each of which may or may not be substituted, and each R 1 silver Optionally including one or more groups selected from ―O―, ―C(O)―, ―C(O)―O―, or ―S― as part of its structure, and any two R 1 The qi selectively forms a ring together; R 2 is independently hydrogen, fluorine, linear C 1-20　Alkyl, branched C 3-20　 Alkyl, monocyclic, or polycyclic C 3-20　 Cycloalkyl, linear C 2-20　 Alkenyl, branched C 3-20　 Alkenyl, monocyclic, or polycyclic C 3-20　 Cycloalkenyl, monocyclic or polycyclic C 6-20　 Aryl, or monocyclic or polycyclic C 2-20　 Heteroaryl, preferably hydrogen, linear C 1-6　 Alkyl, branched C 3-6　 Alkyl, or monocyclic or polycyclic C 3-10　 They are cycloalkyl, each of which may or may not be substituted, and each R 2 is optionally included as part of its structure one or more groups selected from ―O―, ―C(O)―, ―C(O)―O―, or ―S―, and R 2 The qi selectively forms a ring together; R 3 is linear C 1-20　 Alkyl, branched C 3-20　 Alkyl, monocyclic, or polycyclic C 3-20　 Cycloalkyl, linear C 2-20 Alkenyl, branched C 3-20 Alkenyl, monocyclic, or polycyclic C 3-20 Cycloalkenyl, monocyclic or polycyclic C 6-20　 Aryl, or monocyclic or polycyclic C 2-20　 Heteroaryl, preferably linear C 1-6　 Alkyl, branched C 3-6　 Alkyl, or monocyclic or polycyclic C 3-10　 cycloalkyl, each of which is substituted or unsubstituted, R 3 silver Optionally comprising one or more groups selected from ―O―, ―C(O)―, ―C(O)―O―, or ―S― as part of its structure, and one R 2 is R 3It optionally forms a ring together with. These monomers are typically vinyl aromatic, (meth)acrylate, or norbornyl monomers. The total content of polymerized units containing acid-degradable groups that form carboxylic acid groups on the polymer is typically 10 to 100 mol%, more typically 10 to 90 mol%, or 30 to 70 mol% based on the total polymerized units of the polymer.

[0018] The polymer may further comprise polymerized monomers containing acid-unstable groups, which decompose to form alcohol or fluoroalcohol groups on the polymer. Suitable such groups are, for example, of the general formula ―COC(R 2 )2OR 3 It contains an acetal group of — or a carbonate ester group of the general formula —OC(O)O—, wherein R is as defined above. Such monomers are typically vinyl aromatic, (meth)acrylate, or norbornyl monomers. When present in the polymer, the total content of polymerized units containing acid-degradable groups (which decompose to form alcohol or fluoroalcohol groups on the polymer) is typically 10 to 90 mol%, more typically 30 to 70 mol%, based on the total polymerized units of the polymer.

[0019] In an embodiment where the first resist is a photoresist, the first resist comprises a photogenerator. The photogenerator is a compound capable of generating acid upon chemical radiation or radiation irradiation. The photogenerator may be selected from known compounds capable of generating acid upon chemical radiation or radiation irradiation, and may include photoinitiators for cationic photopolymerization, photoinitiators for radical photopolymerization, photochromic agents for dyes, photochromic agents, microresists, etc., and mixtures thereof. Examples of photogenerators include diazonium salts, phosphonium salts, sulfonium salts, iodonium salts, imidosulfonates, oximesulfonates, diazodisulfones, disulfones, and o-nitrobenzyl sulfonates.

[0020] Suitable minerals include onium salts, e.g., triphenylsulfonium trifluoromethanesulfonate, (p-tert-butoxyphenyl)diphenylsulfonium trifluoromethanesulfonate, tris(p-tert-butoxyphenyl)sulfonium trifluoromethanesulfonate, triphenylsulfonium p-toluenesulfonate; di-t-butyphenyliodonium perfluorobutanesulfonate, and di-t-butyphenyliodonium camphosulfonate. Non-ionic sulfonates and sulfonyl compounds, e.g., nitrobenzyl derivatives, e.g., 2-nitrobenzyl-p-toluenesulfonate, 2,6-dinitrobenzyl-p-toluenesulfonate, and 2,4-dinitrobenzyl-p-toluenesulfonate; Sulfonic acid esters, e.g., 1,2,3-tris(methanesulfonyloxy)benzene, 1,2,3-tris(trifluoromethanesulfonyloxy)benzene, and 1,2,3-tris(p-toluenesulfonyloxy)benzene; diazomethane derivatives, e.g., bis(benzenesulfonyl)diazomethane, bis(p-toluenesulfonyl)diazomethane; glyoxime derivatives, e.g., bis-O-(p-toluenesulfonyl)-α-dimethylglyoxime, and bis-O-(n-butanesulfonyl)-α-dimethylglyoxime; sulfonic acid ester derivatives of N-hydroxyimide compounds, e.g., N-hydroxysuccinimide methanesulfonic acid ester, N-hydroxysuccinimide trifluoromethanesulfonic acid ester; and halogen-containing triazine compounds, e.g., 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine and 2-(4-methoxynaphthyl)-4,6-bis(trichloromethyl)-1,3,5-triazine, are also well known to function as photogenerators. Suitable non-polymerized photogenerators are further described in column 37, lines 11 to 47 and columns 41 to 91 of U.S. Patent No. 8,431,325 by Hashimoto et al.Other suitable sulfonate PAGs include sulfonated esters and sulfonyloxy ketones, nitrobenzyl esters, s-triazine derivatives, benzoin tosylates, t-butylphenyl α-(p-toluenesulfonyloxy)-acetate, and t-butyl α-(p-toluenesulfonyloxy)-acetate; as described in U.S. Patents No. 4,189,323 and No. 8,431,325. Onium salt PAGs typically comprise an anion having a sulfonate group or a non-sulfonate type group, such as a sulfonamidate group, a sulfonimidate group, a methide group, or a borate group.

[0021] The resist composition may optionally include a plurality of PAGs. The plurality of PAGs may be polymeric or non-polymeric, or may include both polymeric and non-polymeric PAGs. Preferably, each of the plurality of PAGs is non-polymeric. Preferably, when a plurality of PAGs are used, the first PAG comprises a sulfonate group on the anionic phase, and the second PAG comprises an anion without a sulfonate group, and such anion contains, for example, a sulfonamidate group, a sulfonimidate group, a methid group, or a borate group as described above.

[0022] A first relief pattern can be formed by depositing a first resist on a substrate and then developing the first resist. The first resist can be developed according to a procedure known in the art, for example, by exposing it to chemical radiation and then rinsing it with a first resist developer. To impart a shape or relief pattern to the developed resist, a mask may be used to block a portion of the resist from chemical radiation. After chemical radiation is applied, the unexposed portion of the resist may have a different solubility than the exposed portion of the resist. Subsequently, when rinsed with a first resist developer, either the unexposed portion or the exposed portion dissolves. The relief pattern provided when the unexposed portion of the resist remains after rinsing with the developer is a positive tone developed resist. In contrast, the relief pattern provided when the exposed portion of the resist remains after rinsing with the developer is a negative tone developed resist.

[0023] In one or more embodiments, the first resist is a positive tone developed (PTD) resist. In these embodiments, the first relief pattern may comprise a polymer prepared from the monomers described above, wherein any monomers containing reactive functional groups are protected. As such, since the PTD first resist may be organically soluble, the relief pattern may be provided by rinsing with a basic first resist developer. Suitable basic first resist developers include quaternary ammonium hydroxides, such as tetramethylammonium hydroxide (TMAH).

[0024] Alternatively, in one or more embodiments, the first resist is a negative resist. In such embodiments, the first relief pattern may comprise a polymer prepared from the monomers described above, wherein any monomers containing reactive functional groups are not protected. When exposed to chemical radiation, the polymer cross-links in the exposed areas, causing the developer to render the polymer insoluble. Subsequently, the unexposed and uncrosslinked areas can be removed using a suitable developer to form the relief pattern.

[0025] In another embodiment, the first resist is a negative tone developed (NTD) resist. Similar to the PTD resist, the NTD resist may comprise a polymer prepared from the monomers described above, wherein any monomer containing a reactive functional group is protected. Thus, the NTD first resist may be organically soluble, but instead of developing the exposed area with a first resist developer that is basic, the first resist may be rinsed with a first resist developer that contains an organic solvent to provide a first relief pattern. Suitable organic solvents that may be used as the first resist developer include n-butyl acetate (NBA) and 2-heptanone. The tone of the resist (i.e., PTD versus negative versus NTD) may influence the subsequent chemistry applied to the first relief pattern. In one or more embodiments, the NTD resist is advantageous over the PTD resist. The resist may be selected to be soluble in a solvent that does not dissolve the base pattern.

[0026] In another embodiment, the first resist optionally contains other additives, wherein the other additives include at least one of a resin having at least a fluorine atom or a silicon atom, a basic compound, a surfactant, an onium carboxylate, a dye, a plasticizer, a photosensitizer, a light absorber, an alkali-soluble resin, a dissolution inhibitor, and a compound for promoting dissolution in a developer.

[0027] As described above, the first relief pattern may include features separated by a gap. In one or more embodiments, the features of the first relief pattern may have a thickness of about 300 to about 3000 Å. The gap separating the features may leave a portion of the exposed substrate.

[0028] In some embodiments, the first relief pattern is stabilized before coating with a solubility converter. Various resist stabilization techniques, also known as freezing processes such as ion implantation, UV curing, thermal hardening, thermal curing, and chemical curing, have been proposed. Techniques are described, for example, in U.S. Patent Publication US2008 / 0063985A1, U.S. Patent Publication US2008 / 0199814A1, and U.S. Patent Publication US2010 / 0330503A1.

[0029] In block (106) of the method (100), the first relief pattern is coated with a first solubility converter. A substrate coated according to block (106) is illustrated in FIG. 2B. The first solubility converter (205) is illustrated as a thin coating on the first relief pattern (204). The thickness of the first solubility converter coating is not particularly limited and can be changed based on the desired high-density contact array pattern. The first solubility converter can be absorbed into the first resist. The process of absorbing the solubility converter into the first resist is described in detail below. Alternatively, the first solubility converter is incorporated into the first resist of the first relief pattern. In this embodiment, no coating is required, and the first solubility converter can be uniformly dispersed throughout the first resist.

[0030] As mentioned above, in one or more embodiments, the first solubility converting agent is absorbed into the first relief pattern. The absorption of the first solubility converting agent into the first relief pattern can be achieved by performing a thermal pretreatment such as baking. The baking may be soft baking. The temperature and time of soft baking may vary depending on the characteristics of the first resist and the desired amount of diffusion of the solubility converting agent into the first resist. Typically, soft baking may be performed for about 30 to 90 seconds at a temperature range of about 50°C to about 150°C.

[0031] Alternatively, in one or more embodiments, the first solubility modifier is formulated within the first resist. In such embodiments, the solubility modifier may be included in the first resist in an inert form so as not to alter the solubility of the first resist. Subsequently, the first solubility modifier may be activated later in the method (100) to activate and induce a desired solubility change in the desired material.

[0032] The composition of the first solubility modifier may vary depending on the tone of the first resist. Generally, the first solubility modifier may be any chemical that is activated by light or heat. For example, if the first resist is a PTD resist, the first solubility modifier may include an acid or a thermal acid generator (TAG). In the case of a TAG, the acid or generated acid must be sufficiently hot to cleave the bonds of the acid-degradable groups of the polymer in the surface area of ​​the first resist pattern to increase the solubility of the first resist polymer in the specific developer to be applied. The acid or TAG is typically present in the composition in an amount of about 0.01 to 20 weight percent based on the total solids of the trimming composition.

[0033] Preferred acids are organic acids including non-aromatic and aromatic acids, each of which may optionally have fluorine substitution. Suitable organic acids are carboxylic acids such as alkanes, for example, formic acid, acetic acid, propionic acid, butyric acid, dichloroacetic acid, trichloroacetic acid, perfluoroacetic acid, perfluorooctanoic acid, oxalic acid, malonic acid, and succinic acid; hydroxyalkanes such as citric acid; aromatic carboxylic acids such as benzoic acid, fluorobenzoic acid, hydroxybenzoic acid, and naphthoic acid; organic phosphoric acids such as dimethyl phosphate and dimethylphosphinic acid; and includes sulfonic acids such as optionally fluorinated alkylsulfonic acids, including methanesulfonic acid, trifluoromethanesulfonic acid, ethanesulfonic acid, 1-butanesulfonic acid, 1-perfluorobutanesulfonic acid, 1,1,2,2-tetrafluorobutane-1-sulfonic acid, 1,1,2,2-tetrafluoro-4-hydroxybutane-1-sulfonic acid, 1-pentanesulfonic acid, 1-hexanesulfonic acid, and 1-heptanesulfonic acid.

[0034] Exemplary fluorine-free aromatic acids include aromatic acids of the following general formula (I):

[0035]

[0036] In the above formula: R1 independently represents a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C5-C20 aryl group, or a combination thereof, and optionally contains one or more groups selected from carbonyl, carbonyloxy, sulfonamido, ether, thioether, a substituted or unsubstituted alkylene group, or a combination thereof; Z1 independently represents a group selected from carboxyl, hydroxy, nitro, cyano, C1 to C5 alkoxy, formyl, and sulfonic acid; a and b are independently integers from 0 to 5; and a+b is 5 or less.

[0037] An exemplary aromatic acid may be general formula (II):

[0038]

[0039] In the above formula: R2 and R3 each independently represent a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C5-C16 aryl group, or a combination thereof, and optionally contain one or more groups selected from carbonyl, carbonyloxy, sulfonamido, ether, thioether, a substituted or unsubstituted alkylene group, or a combination thereof; Z2 and Z3 each independently represent a group selected from carboxyl, hydroxy, nitro, cyano, C1 to C5 alkoxy, formyl, and sulfonic acid; c and d are independently integers from 0 to 4; c+d is 4 or less; e and f are independently integers from 0 to 3; and e+f is 3 or less.

[0040] Additional aromatic acids that may be included in the solubility modifier include those of general formula (III) or (IV):

[0041]

[0042] In the above formula: R4, R5 and R6 each independently represent a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C5-C12 aryl group, or a combination thereof, and optionally contain one or more groups selected from carbonyl, carbonyloxy, sulfonamido, ether, thioether, a substituted or unsubstituted alkylene group, or a combination thereof; Z4, Z5 and Z6 each independently represent a group selected from carboxyl, hydroxy, nitro, cyano, C1-C5 alkoxy, formyl, and sulfonic acid; g and h are independently integers from 0 to 4; g+h is 4 or less; i and j are independently integers from 0 to 2; i+j is 2 or less; k and 1 are independently integers from 0 to 3; and k+l is 3 or less;

[0043]

[0044] In the above formula: R4, R5 and R6 each independently represent a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C5-C12 aryl group or a combination thereof, and optionally contain one or more groups selected from carbonyl, carbonyloxy, sulfonamido, ether, thioether, a substituted or unsubstituted alkylene group, or a combination thereof; Z4, Z5 and Z6 each independently represent a group selected from carboxyl, hydroxy, nitro, cyano, C1 to C5 alkoxy, formyl, and sulfonic acid; g and h are independently integers from 0 to 4; g+h is 4 or less; i and j are independently integers from 0 to 1; i+j is 1 or less; k and l are independently integers from 0 to 4; and k+l is 4 or less.

[0045] A suitable aromatic acid can alternatively be general formula (V):

[0046]

[0047] In the above formula: R7 and R8 each independently represent a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C5-C14 aryl group, or a combination thereof, and optionally contain one or more groups selected from carboxyl, carbonyl, carbonyloxy, sulfonamido, ether, thioether, a substituted or unsubstituted alkylene group, or a combination thereof; Z7 and Z8 each independently represent a group selected from hydroxyl, nitro, cyano, C1 to C5 alkoxy, formyl, and sulfonic acid; m and n are independently integers from 0 to 5; m+n is 5 or less; o and p are independently integers from 0 to 4; and o+p is 4 or less.

[0048] Additionally, exemplary aromatic acids may have the general formula (VI):

[0049]

[0050] In the above formula: X is O or S; R9 independently represents a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C5-C20 aryl group or a combination thereof, and optionally contains one or more groups selected from carbonyl, carbonyloxy, sulfonamido, ether, thioether, a substituted or unsubstituted alkylene group, or a combination thereof; Z9 independently represents a group selected from carboxyl, hydroxy, nitro, cyano, C1 to C5 alkoxy, formyl, and sulfonic acid; q and r are independently integers from 0 to 3; and q+r is 3 or less.

[0051] In one or more embodiments, the acid is a free acid having fluorine substitution. Suitable free acids having fluorine substitution may be aromatic or non-aromatic. For example, free acids having fluorine substitution that can be used as solubility modifiers include, without limitation, the following:

[0052]

[0053]

[0054]

[0055] Suitable TAGs include those capable of producing the non-polymeric acid described above. The TAG may be non-ionic or ionic. Suitable nonionic thermal acid generating agents are, for example, cyclohexyl trifluoromethyl sulfonate, methyl trifluoromethyl sulfonate, cyclohexyl p-toluenesulfonate, methyl p-toluenesulfonate, cyclohexyl 2,4,6-triisopropylbenzenesulfonate, nitrobenzyl ester, benzoin tosylate, 2-nitrobenzyl tosylate, tris(2,3-dibromopropyl)-1,3,5-triazine-2,4,6-trione, alkyl esters of organic sulfonic acids, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, oxalic acid, phthalic acid, phosphoric acid, camphosulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, triisopropylnaphthalenesulfonic acid, 5-nitro-o-toluenesulfonic acid, 5-sulfosalicylic acid, 2,5-dimethylbenzene It includes sulfonic acids, 2-nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 3-bromobenzenesulfonic acid, 2-fluorocaprylnaphthalenesulfonic acid, dodecylbenzenesulfonic acid, 1-naphthol-5-sulfonic acid, 2-methoxy-4-hydroxy-5-benzoylbenzenesulfonic acid, and salts thereof, and combinations thereof. Suitable ionic thermal acid generating agents include, for example, dodecylbenzenesulfonic acid triethylamine salt, dodecylbenzenedisulfonic acid triethylamine salt, p-toluenesulfonic acid-ammonium salt, p-toluenesulfonic acid-pyridinium salt, sulfonate salts, for example, carbocyclic aryl and heteroaryl sulfonate salts, aliphatic sulfonate salts, and benzenesulfonate salts. Compounds that produce sulfonic acid upon activation are generally suitable. Preferred thermal acid generators include ammonium p-toluenesulfonate salts and heteroaryl sulfonate salts.

[0056] Preferably, the TAG is ionic, having a reaction scheme for the production of sulfonic acid as described below:

[0057]

[0058] In the above formula, RSO3 - is a TAG anion and X +is a TAG cation, preferably an organic cation. The cation may be a nitrogen-containing cation of general formula (I):

[0059]

[0060] This is a monoprotic form of a nitrogen-containing base B. Suitable nitrogen-containing base B comprises, for example: optionally substituted amines, e.g., ammonia, difluoromethylammonium, C1-20 alkyl amines, and C3-30 aryl amines, e.g., nitrogen-containing heteroaromatic bases; bases, e.g., pyridine or substituted pyridine (e.g., 3-fluoropyridine), pyrimidine, and pyrazine; nitrogen-containing heterocyclic groups, e.g., oxazole, oxazolin, or thiazolin. The aforementioned nitrogen-containing base B may be optionally substituted with one or more groups selected from, for example, alkyl, aryl, halogen atoms (preferably fluorine), cyano, nitro, and alkoxy. Among these, base B is preferably a heteroaromatic base.

[0061] Base B typically has a pKa of 0 to 5.0, or 0 to 4.0, or 0 to 3.0, or 1.0 to 3.0. As used herein, the term “pKa” is used according to the meaning recognized in the art, namely, pKa is approximately the conjugate acid (BH) of the basic moiety (B) in aqueous solution at room temperature. + It is the negative logarithm of the dissociation constant (for base 10). In certain embodiments, base B has a boiling point of less than about 170°C, or less than about 160°C, 150°C, 140°C, 130°C, 120°C, 110°C, 100°C, or 90°C.

[0062] Exemplary suitable nitrogen-containing cation (BH) + is NH4 + , CF2HNH2 + , CF3CH2NH3 + , (CH3)3NH + , (C2H5)3NH +, (CH3)2(C2H5)NH + Includes and

[0063]

[0064] In the above formula, Y is alkyl, preferably methyl or ethyl.

[0065] In certain embodiments, the solubility converting agent may be an acid, e.g., trifluoromethanesulfonic acid, perfluoro-1-butanesulfonic acid, p-toluenesulfonic acid, 4-dodecylbenzenesulfonic acid, 2,4-dinitrobenzenesulfonic acid, and 2-trifluoromethylbenzenesulfonic acid; an acid generating agent, e.g., triphenylsulfonium antimonate, pyridinium perfluorobutanesulfonate, 3-fluoropyridinium perfluorobutanesulfonate, 4-t-butylphenyltetramethylenesulfonium perfluoro-1-butanesulfonate, 4-t-butylphenyltetramethylenesulfonium 2-trifluoromethylbenzenesulfonate, and 4-t-butylphenyltetramethylenesulfonium 4,4,5,5,6,6-hexafluorodihydro-4H-1,3,2-dithiazine 1,1,3,3-tetraoxide; or a combination thereof.

[0066] Alternatively, if the first resist is an NTD resist, the first solubility converting agent may include a base or a base generating agent. In this embodiment, suitable solubility converting agents include, but are not limited to, hydroxides, carboxylates, amines, imines, amides, and mixtures thereof. Specific examples of bases include ammonium carbonate, ammonium hydroxide, ammonium hydrogen phosphate, ammonium phosphate, tetramethylammonium carbonate, tetramethylammonium hydroxide, tetramethylammonium hydrogen phosphate, tetramethylammonium phosphate, tetraethylammonium carbonate, tetraethylammonium hydroxide, tetraethylammonium hydrogen phosphate, tetraethylammonium phosphate, and combinations thereof. Amines include aliphatic amines, cycloaliphatic amines, aromatic amines, and heterocyclic amines. Amines may be primary, secondary, or tertiary amines. The amine may be a monoamine, diamine, or polyamine. Suitable amines may include C1-30 organic amines, imines, or amides, or may be C1-30 quaternary ammonium salts of strong bases (e.g., hydroxides or alkoxides) or weak bases (e.g., carboxylates). Exemplary bases are amines, e.g., tripropylamine, dodecylamine, tris(2-hydroxypropyl)amine, tetrakis(2-hydroxypropyl)ethylenediamine; It comprises an aryl amine, e.g., diphenylamine, triphenylamine, aminophenol, and 2-(4-aminophenyl)-2-(4-hydroxyphenyl)propane, Troger base, a hindering amine, e.g., diazabicycloundecene (DBU) or diazabicyclononene (DBN), an amide-like tert-butyl 1,3-dihydroxy-2-(hydroxymethyl)propane-2-ylcarbamate and tert-butyl 4-hydroxypiperidin-1-carboxylate; or an ionic quenching agent comprising a quaternary alkyl ammonium salt, e.g., tetrabutylammonium hydroxide (TBAH) or tetrabutylammonium lactate. In another embodiment, the amine is a hydroxyamine.Examples of hydroxyamines include hydroxyamines having one or more hydroxyalkyl groups, such as hydroxymethyl, hydroxyethyl, and hydroxybutyl groups, each having 1 to about 8 carbon atoms, preferably 1 to about 5 carbon atoms. Specific examples of hydroxyamines include mono-, di-, and tri-ethanolamines, 3-amino-1-propanol, 2-amino-2-methyl-1-propanol, 2-amino-2-ethyl-1,3-propanediol, tris(hydroxymethyl)aminomethane, N-methylethanolamine, 2-diethylamino-2-methyl-1-propanol, and triethanolamine.

[0067] Suitable base generators may be thermal base generators. Thermal base generators form a base when heated above a first temperature, typically about 140°C or higher. Thermal base generators may include functional groups such as amides, sulfonamides, imides, imines, O-acyl oximes, benzoyloxycarbonyl derivatives, quaternary ammonium salts, nifedipine, carbamates, and combinations thereof. Exemplary thermobase generators include o-{(.beta.-(dimethylamino)ethyl)aminocarbonyl}benzoic acid, o-{(.gamma.-(dimethylamino)propyl)aminocarbonyl}benzoic acid, 2,5-bis{(.beta.-(dimethylamino)ethyl)aminocarbonyl}terephthalic acid, 2,5-bis{(.gamma.-(dimethylamino)propyl)aminocarbonyl}terephthalic acid, 2,4-bis{(.beta.-(dimethylamino)ethyl)aminocarbonyl}isophthalic acid, 2,4-bis{(.gamma.-(dimethylamino)propyl)aminocarbonyl}isophthalic acid, and combinations thereof.

[0068] In one or more embodiments, the first solubility converting agent comprises a solvent. The solvent may be any suitable solvent as long as it does not dissolve the first resist. The solvent is typically selected from water, organic solvents, and mixtures thereof. In some embodiments, the solvent may comprise an organic solvent system comprising one or more organic solvents. The term “organic” means that the solvent system comprises more than 50 wt% of an organic solvent based on the total solvent of the solubility converting agent composition, more typically more than 90 wt%, more than 95 wt%, more than 99 wt%, or 100 wt% of an organic solvent based on the total solvent of the solubility converting agent composition. The solvent component is typically present in an amount of 90 to 99 wt% based on the solubility converting agent composition.

[0069] Suitable organic solvents for solubility-converting agent compositions are, for example, alkyl esters such as alkyl propionates such as n-butyl propionate, n-pentyl propionate, n-hexyl propionate, and n-heptyl propionate, and alkyl butyrates such as n-butyl butyrate, isobutyl butyrate, and isobutyl isobutyrate; ketones such as 2,5-dimethyl-4-hexanone and 2,6-dimethyl-4-heptanone; aliphatic hydrocarbons such as n-heptane, n-nonane, n-octane, n-decane, 2-methylheptane, 3-methylheptane, 3,3-dimethylhexane, and 2,3,4-trimethylpentane, and fluorinated aliphatic hydrocarbons such as perfluoroheptane; alcohols such as straight-chain, branched, or cyclic C4-C 9　Monohydrogen alcohols, e.g., 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 3-methyl-1-butanol, 1-pentanol, 2-pentanol, 4-methyl-2-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 2-hexanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol, 3-octanol, and 4-octanol; It comprises 2,2,3,3,4,4-hexafluoro-1-butanol, 2,2,3,3,4,4,5,5-octafluoro-1-pentanol and 2,2,3,3,4,4,5,5,5,6,6-decafluoro-1-hexanol, and C5-C9 fluorinated diols such as 2,2,3,3,4,4-hexafluoro-1,5-pentanediol, 2,2,3,3,4,4,5,5-octafluoro-1,6-hexanediol and 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoro-1,8-octanediol; ethers such as isopentyl ether and dipropylene glycol monomethyl ether; and a mixture containing one or more of these solvents.

[0070] The solvent included in the absorbed material may vary depending on the composition and the tone of the first resist. As is typical for ArF resists, when the first resist is formed from a (meth)acrylate polymer and the resist is developed as a PTD resist, the solvent system preferably comprises one or more polar organic solvents. For example, a solubility modifier intended to be absorbed into the PTD first photoresist may comprise a polar solvent such as methyl isobutyl carbinol (MIBC). The solubility modifier may also comprise aliphatic hydrocarbons, esters, and ethers as cosolvants, such as decane, isobutyl isobutyrate, isoamyl ether, and combinations thereof. In certain embodiments, the solvent comprises MIBC and a cosolvent. In such embodiments, MIBC may be included in the solvent in an amount ranging from 60 to 99% based on the total volume of the solvent. Thus, the cosolvent may be included in an amount ranging from 1 to 40% based on the total volume of the solvent.

[0071] As is typical for KrF and EUV photoresists, where the first resist is formed from a vinyl aromatic polymer and the resist is developed as a PTD resist, the solvent system preferably comprises one or more nonpolar organic solvents. The term "nonpolar organic" means that the solvent system comprises a combined nonpolar organic solvent of more than 50 wt% based on the total solvent of the solubility converting agent composition, more typically a combined nonpolar organic solvent of more than 70 wt%, more than 85 wt%, or 100 wt% based on the total solvent of the solubility converting agent composition. The nonpolar organic solvent is typically present in the solvent system in a combined amount of 70 to 98 wt%, preferably 80 to 95 wt%, and more preferably 85 to 98 wt% based on the solvent system.

[0072] Suitable nonpolar solvents include, for example, ethers, hydrocarbons, and combinations thereof, with ethers being preferred. Suitable ether solvents include, for example, alkyl monoethers and aromatic monoethers, and those having a total number of carbon atoms of 6 to 16 are particularly preferred. Suitable alkyl monoethers include, for example, 1,4-cineol, 1,8-cineol, pinene oxide, di-n-propyl ether, diisopropyl ether, di-n-butyl ether, di-n-pentyl ether, diisoamyl ether, dihexyl ether, diheptyl ether, and dioctyl ether, with diisoamyl ether being preferred. Suitable aromatic monoethers include, for example, anisole, ethylbenzyl ether, diphenyl ether, dibenzyl ether, and phenethol, with anisole being preferred. Suitable aliphatic hydrocarbons include, for example, n-heptane, 2-methylheptane, 3-methylheptane, 3,3-dimethylhexane, 2,3,4-trimethylpentane, n-octane, n-nonane, n-decane, and fluorinated compounds, for example, perfluoroheptane. Suitable aromatic hydrocarbons include, for example, benzene, toluene, and xylene.

[0073] In some embodiments, the solvent system further comprises one or more alcohol and / or ester solvents. For certain compositions, the alcohol and / or ester solvents may provide enhanced solubility for the solid components of the composition. Suitable alcohol solvents are, for example: straight-chain, branched, or cyclic C 4-9　 Monohydrogen alcohols, e.g., 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 3-methyl-1-butanol, 1-pentanol, 2-pentanol, 4-methyl-2-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 2-hexanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol, 3-octanol, 4-octanol, 2,2,3,3,4,4-hexafluoro-1-butanol, 2,2,3,3,4,4,5,5-octafluoro-1-pentanol, and 2,2,3,3,4,4,5,5,6,6-decafluoro-1-hexanol; and C 5-9 Fluorinated diols include, for example, 2,2,3,3,4,4-hexafluoro-1,5-pentanediol, 2,2,3,3,4,4,5,5-octafluoro-1,6-hexanediol, and 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoro-1,8-octanediol. The alcohol solvent is preferably C 4-9　 It is a monohydrogen alcohol, and 4-methyl-2-pentanol is preferred. Suitable ester solvents include, for example, alkyl esters having a total number of 4 to 10 carbon atoms, for example, alkyl propionates, for example, n-butyl propionate, n-pentyl propionate, n-hexyl propionate, and n-heptyl propionate, and alkyl butyrates, for example, n-butyl butyrate, isobutyl butyrate, and isobutyl isobutyrate. When used in a solvent system, one or more alcohol and / or ester solvents are present in a combined amount of typically 2 to 50 weight%, more typically 2 to 30 weight%, based on the solvent system.

[0074] The solvent system may also comprise one or more additional solvents selected from, for example, ketones, e.g., 2,5-dimethyl-4-hexanone and 2,6-dimethyl-4-heptanone; and polyethers, e.g., dipropylene glycol monomethyl ether and tripropylene glycol monomethyl ether. When used, these additional solvents are typically present in a combined amount of 1 to 20 weight percent based on the solvent system.

[0075] When the first resist is formed from a vinyl aromatic polymer, a particularly preferred organic solvent system comprises a combined amount of one or more monoether solvents in an amount of 70 to 98 weight percent based on the solvent system, and a combined amount of one or more alcohol and / or ester solvents in an amount of 2 to 30 weight percent based on the solvent system. The solvent system is present in the overcoat composition in an amount of typically 90 to 99 weight percent, preferably 95 to 99 weight percent, based on the overcoat composition.

[0076] As described above, in one or more embodiments, the first solubility-converting agent is coated over the first relief pattern. To adequately coat the first relief pattern, the first solubility-converting agent may comprise a matrix polymer. Any matrix polymer commonly used in the art may be included in the first solubility-converting material. The matrix polymer must have excellent solubility in a solvent that does not dissolve the first resist. The matrix polymer is one or more monomers selected from those having ethyleneally unsaturated polymerizable double bonds, for example: (meth)acrylate monomers, e.g., isopropyl(meth)acrylate and n-butyl(meth)acrylate; (meth)acrylic acid; vinyl aromatic monomers, e.g., styrene, hydroxystyrene, vinyl naphthalene and acenaphtylene; vinyl alcohol; vinyl chloride; vinyl pyrrolidone; vinyl pyridine; vinyl amine; vinyl acetal; maleic anhydride; maleimide, norbornene; It can be formed from one or more selected from those including combinations thereof.

[0077] In some embodiments, the polymer contains one or more functional groups selected from, for example, hydroxyl, acid groups, for example, carboxyl, sulfonic acid and sulfonamide, silanol, fluoroalcohols, for example, hexafluoroisopropyl alcohol [―C(CF3)2OH], anhydrides, lactones, esters, ethers, allylamines, pyrrolidone, and combinations thereof. The polymer may be a homopolymer or copolymer having a number of distinct repeating units, for example, two, three, four, or more distinct repeating units. In one embodiment, the repeating units of the polymer are all formed from (meth)acrylate monomers, all formed from (vinyl)aromatic monomers, or all formed from (meth)acrylate monomers and (vinyl)aromatic monomers. If the polymer contains more than one type of repeating unit, it typically takes the form of a random copolymer.

[0078] In certain embodiments, the matrix polymer may be a t-butyl acrylate (TBA) / p-hydroxystyrene (PHS) copolymer, a butyl acrylate (BA) / PHS copolymer, a TBA / methacrylic acid (MAA) copolymer, a BA / MAA copolymer, a PHS / methacrylate (MA) copolymer, and combinations thereof.

[0079] The solubility converting agent composition typically comprises a homopolymer but may optionally comprise one or more additional polymers. The content of the polymer in the composition will vary, for example, depending on the target thickness of the layer, and a higher polymer content is used when a thicker layer is desired. The polymer is present in the patterned solubility converting agent composition in an amount of typically 80 to 99.9 wt%, more typically 90 to 99 wt%, or 95 to 99 wt% based on the total solids of the solubility converting agent composition. The weight-average molecular weight (Mw) of the polymer is typically less than 400,000, preferably 3,000 to 50,000, more preferably 3,000 to 25,000, as measured by the GPC to polystyrene standard. Typically, the polymer has a polydispersity index (PDI=Mw / Mn) of 3 or less, preferably 2 or less, as measured by the GPC to polystyrene standard.

[0080] Polymers suitable for use in solubility-converting agent compositions are commercially available and / or can be readily manufactured by those skilled in the art. For example, the polymer may be synthesized by the steps of dissolving a selected monomer corresponding to a polymer unit in an organic solvent, adding a radical polymerization initiator thereto, and performing thermal polymerization to form a polymer. Examples of suitable organic solvents that can be used for the polymerization of the polymer include, for example, toluene, benzene, tetrahydrofuran, diethyl ether, dioxane, ethyl lactate, and methyl isobutyl carbinol. Suitable polymerization initiators include, for example, 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, and lauroyl peroxide.

[0081] A solubility-converting agent comprising a matrix polymer may be coated onto a first relief pattern according to methods known in the art. Typically, the solubility-converting agent comprising a matrix polymer may be coated onto the first relief pattern by spin coating. The solid content of the first solubility-converting agent may be adjusted to provide a film of the first solubility-converting agent of a desired thickness onto the first relief pattern. For example, the solid content of the first solubility-converting agent solution may be adjusted to provide a desired film thickness based on the specific coating equipment used, the viscosity of the solution, the speed of the coating tool, and the time allowed for spinning. Typical thicknesses of the composition are about 200 Å to about 1500 Å.

[0082] In one or more embodiments, the first solubility modifier comprises an active substance (i.e., acid, acid-generating agent, base, or base-generating agent), a solvent, and a matrix polymer as previously described. A typical formulation of such a solubility modifier may comprise about 1 to about 10 weight percent of solid and about 90 to about 99 weight percent of solvent based on the total weight of the solubility modifier, wherein the solid comprises the active substance and the matrix polymer. Of the solid content, the active substance may be included in an amount of about 1 to about 5 weight percent.

[0083] The first solubility converter may include additives having various purposes depending on the specific chemicals used. In some embodiments, a surfactant may be included in the solubility converter. In particular, a surfactant may be included in the solubility converter to help with coating quality when thin gaps between the first resist features need to be filled. Any suitable surfactant known in the art may be included in the solubility converter.

[0084] After absorption into the first relief pattern, a coating layer not containing any active solubility-converting material may remain on the first resist. In one or more embodiments, the coating layer may be removed by rinsing. Rinsing may be achieved by rinsing a substrate coated with a solvent that dissolves the coating layer but does not dissolve the first resist. Rinsing may be performed using any suitable method, for example, by immersing the substrate in a bath filled with solvent for a certain period of time (immersion method), by raising the solvent on the surface of the substrate by the effect of surface tension and dissolving the coating layer by leaving it standing for a certain period of time (puddle method), by spraying the solvent onto the surface of the substrate (spraying method), or by continuously spraying the solvent onto a substrate rotating at a constant speed while injecting a solvent spray nozzle at a constant speed (dynamic dispensing method).

[0085] In block (108) of method (100), a first polymer filler is deposited on a substrate. A coated substrate laminated with a first relief pattern (204), a first solubility converter (205), and a first polymer filler (206) is illustrated in FIG. 2c. The first polymer filler may be deposited on the substrate to fill the gaps of the first relief pattern, and the first polymer filler may come into contact with the first relief pattern or the first solubility converter. When depositing the first polymer filler in this manner, a planar layer must exist on the substrate and the target layer as illustrated in FIG. 2c. In some embodiments, the first polymer filler completely covers the target layer, the first relief pattern, and the first solubility converter. The first polymer filler may be deposited on the substrate according to any suitable method known in the art, such as spin-on deposition or vapor phase processing, for example.

[0086] In one or more embodiments, the first polymer filler comprises a resist. In these embodiments, the resist may be a PTD, negative, or NTD resist as described above. The resist included in the first polymer filler may comprise a polymer. A suitable polymer may be as previously described for a polymer defined as a first resist polymer and / or matrix polymer. In certain embodiments, a suitable polymer may be prepared from monomers comprising p-hydroxystyrene, styrene, t-butyl acrylate, and combinations thereof. In certain embodiments, the polymer is prepared from all three of p-hydroxystyrene, styrene, and t-butyl acrylate. Such a polymer may be prepared from a polymerization reaction comprising about 50% to about 80% p-hydroxystyrene, about 10% to about 30% styrene, and about 10% to about 30% t-butyl acrylate. For example, a polymerization reaction to produce a polymer included in a first polymer filler may include an amount of p-hydroxystyrene in a range of one lower limit of about 50%, about 55%, about 60%, and about 65% to one upper limit of about 65%, about 70%, about 75%, and about 80% (wherein any lower limit may be paired with any mathematically compatible upper limit) and individual amounts of styrene and t-butyl acrylate in a range of one lower limit of about 10%, about 12%, about 14%, about 16%, about 18%, and about 20% to one upper limit of about 20%, about 22%, about 24%, about 26%, about 28%, and about 30% (wherein any lower limit may be paired with any mathematically compatible upper limit).

[0087] The polymer included in the first polymer filler may have a weight average molecular weight (Mw) in the range of about 1 to about 100 kg / mol. For example, in one or more embodiments, the first polymer filler may comprise a polymer having an Mw in the range of one lower limit of 1, 2, 5, 10, 15, 20, and 25 kg / mol to one upper limit of 25, 50, 75, 80, 90, and 100 kg / mol, wherein any lower limit may be paired with any mathematically compatible upper limit. A polymer having such an Mw may exhibit desired solubility characteristics, particularly such as a dissolution rate.

[0088] In one or more embodiments, the first polymer filler comprises a solvent. The solvent may be the same as previously described in relation to the solvent included in the first solubility converter. In certain embodiments, the solvent of the first polymer filler is the same as the solvent of the first solubility converter.

[0089] The first polymer filler may include additives having various purposes depending on the specific chemicals used. In some embodiments, a matting agent is included in the first polymer filler. A matting agent may be included in the first polymer filler to help control the diffusion of the active substance in the solubility-converting agent. A suitable matting agent includes any one of the bases previously listed in relation to the solubility-converting material.

[0090] In block (110) of method (100), the first solubility-converting agent diffuses into the first polymer filler. The first solubility-converting agent may diffuse according to a suitable diffusion method known in the art. However, the specific method and conditions used may vary depending on the characteristics of the first solubility-converting agent, such as activation temperature, diffusivity, etc. In one or more embodiments, diffusion of the first solubility-converting agent into the first polymer filler is achieved by performing baking. Baking may be performed using a hot plate or an oven. The baking temperature and time may vary depending on the characteristics of the first polymer filler and the desired amount of diffusion of the first solubility-converting agent into the first polymer filler. Suitable conditions for baking may include a temperature in the range of 50 to 160°C and a time in the range of about 30 to 90 seconds. In one or more embodiments, a solubility-converted region may exist around the edge of the first polymer filler after baking. The amount of diffusion of the first solubility-converting agent may correspond to the thickness of the solubility-converted region. In some embodiments, the solubility-converted region extends into the first polymer filler to have a thickness of about 5 to about 60 nm. For example, the thickness of the solubility-converted region may be in the range of one lower limit of about 5 nm, about 10 nm, about 15 nm, about 20 nm, and about 25 nm to one upper limit of about 40 nm, about 45 nm, about 50 nm, about 55 nm, and about 60 nm, wherein any lower limit may be paired with any mathematically compatible upper limit. In one or more embodiments, the thickness of the solubility-converted region may correspond to a desired pattern of the high-density contact array to be cut into a target layer.

[0091] A coated substrate including a solubility-converted region of a first polymer filler is illustrated in FIG. 2d. As illustrated in FIG. 2d, the coated substrate comprises a substrate (201) and a target layer (202). The substrate has been previously described. A first relief pattern (204) composed of a first resist (203) is on top of the substrate (202). The first relief pattern (204) is coated with a first solubility-converting agent. A first polymer filler (206) is coated on the substrate to cover the target layer (201) and form a planar layer having the first relief pattern (204). In an alternative embodiment, the first polymer filler completely covers the target layer and the first relief pattern. A solubility-converted region (208) of the first polymer filler is illustrated in contact with the first relief pattern.

[0092] The solubility-converted region may have a different solubility from the region of the first polymer filler that was not exposed to the first solubility-converting agent. As such, the solubility-converted region and the unexposed region of the first polymer filler may be soluble in different resist developers.

[0093] In block (112) of the method (100), a second relief pattern (210) may be formed on the first relief pattern and the first polymer film. In the invention, the planar layer formed by the first polymer film and the first relief pattern may be referred to as the "bottom plane." A bird's-eye view of a coated substrate including the bottom plane and the second relief pattern is shown in FIG. 2e. As shown in FIG. 2e, the second relief pattern may be formed to be orthogonal to the first relief pattern. In one or more embodiments, the second relief pattern may have features separated by gaps similar to the first relief pattern, and the features of the second relief pattern may be formed to intersect the features of the first relief pattern. For example, if the first relief pattern consists of horizontal lines, the second relief pattern may be formed so that the lines intersect as vertical lines. In one or more embodiments, the features of the first and second relief patterns may intersect at a 90° angle. In another embodiment, the features may intersect at a 60° angle. As understood by those skilled in the art, various intersecting angles may be used depending on the desired high-density contact array pattern.

[0094] In one or more embodiments, the features of the second relief pattern are formed by photolithography and manufactured with a second resist (211). The second resist may include a polymer. Suitable polymers that may be included in the second resist are as previously described in relation to the first resist. The second resist may be a PTD or NTD resist as described with reference to the first resist. In one or more embodiments, the second resist is identical to the first resist. To form the second relief pattern without affecting the first relief pattern, a "freeze" may be applied to the first relief pattern. The freeze is a surface treatment that protects the first relief pattern and maintains the integrity of the feature boundaries to prevent dissolution into the second resist.

[0095] In block (114), the second relief pattern is coated with a second solubility converter. FIG. 2f illustrates a coated substrate comprising a lower plane and a second relief pattern coated with the second solubility converter (212). The second solubility converter may be similar to the first solubility converter to the extent that components of the first solubility converter may also be included in the second solubility converter. In one or more embodiments, the second solubility converter comprises an acid or acid-generating agent and a matrix polymer as previously described. Additionally, similar to the first solubility converter, the second solubility converter may be absorbed into the second relief pattern. Alternatively, the second solubility converter may be formulated within the second resist as previously described in relation to the first solubility converter.

[0096] The second solubility converter can be coated onto the second relief pattern by spin coating. The solid content of the second solvent, as measured by the amount of the included matrix polymer, can be adjusted to provide a film of the second solubility converter of a desired thickness onto the second relief pattern. For example, the solid content of the solubility converter solution can be adjusted to provide a desired film thickness based on the specific coating equipment used, the viscosity of the solution, the speed of the coating tool, and the time allowed for spinning. Typical thicknesses of the composition are about 200 Å to about 1500 Å.

[0097] As mentioned above, in one or more embodiments, the second solubility converter is absorbed into the second relief pattern. The absorption of the solubility converter into the first relief pattern can be achieved by performing a thermal pretreatment such as baking. The baking may be soft baking. The temperature and time of soft baking may vary depending on the characteristics of the first resist and the desired amount of diffusion of the solubility converter into the first resist. Typically, soft baking may be performed for about 30 to 90 seconds at a temperature range of about 50°C to 150°C.

[0098] After absorption into the first relief pattern, a coating layer not containing any active solubility-converting material may remain on the second resist. In one or more embodiments, the coating layer may be removed by rinsing. Rinsing may be achieved by rinsing a substrate coated with a solvent that dissolves the coating layer but does not dissolve the first resist. Rinsing may be performed using any suitable method, for example, by immersing the substrate in a bath filled with solvent for a certain period of time (immersion method), by raising the solvent on the surface of the substrate by the effect of surface tension and dissolving the coating layer by leaving it standing for a certain period of time (puddle method), by spraying the solvent onto the surface of the substrate (spraying method), or by continuously spraying the solvent onto a substrate rotating at a constant speed while injecting a solvent spray nozzle at a constant speed (dynamic dispensing method).

[0099] Next, in block (116) of the method (100), a second polymer film is laminated onto a second relief pattern. An example of a coated substrate at this point in the method is shown in FIG. 2g. As shown in FIG. 2g, the second polymer filler (214) can come into contact with the second relief pattern or the second solubility converter and can fill any gap in the second relief pattern that exposes the lower plane. Similar to the deposition of the first polymer film, the deposition of the second polymer film can provide a flattened layer on top of the lower plane. As previously mentioned, this layer may be referred to as the upper plane.

[0100] In one or more embodiments, the second polymer filler comprises a resist comprising a polymer and a solvent, and one or more additives as described above in relation to the first polymer filler. In some embodiments, the second polymer filler is identical to the first polymer filler.

[0101] In block (118) of the method (100), the second solubility converter is diffused into the second polymer filler. In one or more embodiments, the diffusion of the second solubility converter into the second polymer filler is achieved by performing baking. The baking may be soft baking. As described above with respect to the first polymer filler, the temperature and time of soft baking may vary depending on the characteristics of the second polymer filler and the desired amount of diffusion of the second solubility converter into the second polymer filler.

[0102] After soft baking, a solubility-converted region may exist around the edge of the second polymer filler. FIG. 2h illustrates a coated substrate after the second solubility-converting agent has diffused into the second polymer filler to provide a second polymer filler having a solubility-converted region (216). The amount of diffusion of the second solubility-converting agent may correspond to the thickness of the solubility-converted region. In some embodiments, the solubility-converted region extends into the second polymer filler to have a thickness of about 5 to about 60 nm. For example, the thickness of the solubility-converted region may be in the range of one lower limit of 5, 10, 15, 20, and 25 nm to one upper limit of 40, 45, 50, 55, and 60 nm, where any lower limit may be paired with any upper limit that is mathematically compatible. In one or more embodiments, the thickness of the solubility-converted region may correspond to a desired pattern of high-density contact array to be cut into the target layer.

[0103] The solubility-converted region may have a different solubility from the region of the second polymer filler that is not exposed to the solubility-converting agent. As such, the solubility-converted region and the unexposed region of the second polymer filler may be soluble in different resist developers.

[0104] In block (120) of the method (100), the first polymer filler and the second polymer filler may be developed using a specific developer so that the solubility-converted regions of the second polymer filler and the first polymer filler are removed. Depending on the resist of each of the first and second polymer fillers, the development may include additional exposure to chemical radiation, heat treatment, and development by the specific developer. In one or more embodiments, the first and second fillers are first exposed to chemical radiation and then exposed to the specific developer to be developed. In other embodiments, the first and second polymer fillers are exposed only to the specific developer. The specific developer may vary depending on the tone of the resist present in the first and second polymer fillers. In certain embodiments, the first and second polymer fillers may have the same solubility characteristics and thus may be developed using the same specific developer. For example, if the first and second polymer fillers contain a positive tone developed resist, the specific developer may be a base such as tetramethylammonium hydroxide. On the other hand, if the first and second polymer fillers are negative tone developed resists, the specific developer may be a nonpolar organic solvent such as n-butyl acetate or 2-heptanone.

[0105] As previously described, the thickness of the solubility-converted region may correspond to a desired pattern of high-density contact array to be cut into the target layer. FIG. 2i illustrates a coated substrate developed according to an embodiment of the present disclosure. In one or more embodiments, the first and second polymer fillers (206 and 214) are developed to dissolve the solubility-converted region formed on the boundaries of the first and second relief patterns, respectively. The result is an intersecting pattern of very narrow trenches, which defines a sub-resolution contact opening (220) that exposes the target layer (202) when combined. Accordingly, referring again to FIG. 1, block (122) of the method (100) includes the step of etching the exposed portion of the target layer using the first relief pattern, the first polymer filler, the second relief pattern, and the second polymer filler as a combined etching mask (222). This method can provide a high-density contact array to the target layer. The etching process may be an isotropic or anisotropic etching process using any suitable dry etchant such as CF, O, HBr, or F. In one embodiment, the etchant may be a dry etchant such as CF, O, HBr, and F.

[0106] Referring to FIG. 1, it will be understood that in a variation of the method (100), additional development and etching may occur after diffusing the first solubility converter, such that development and etching occur respectively after diffusing the first and second solubility converters. Accordingly, in one or more embodiments, a first pattern line may be etched onto a target layer on a substrate, and then a second orthogonal pattern line may be etched into the substrate. For example, a method (300) according to such an embodiment of the present disclosure is illustrated and discussed with reference to FIG. 3.

[0107] In FIG. 3, a target layer is provided on a substrate in block (302). In one or more embodiments, the target layer is a hard mask layer. Then, in block (304), a first relief pattern may be laminated on the target layer. The first relief pattern may include features separated by a gap so that a portion of the target layer is exposed. The first relief pattern may include a first resist as described above. Then, the method (300) includes the step of coating the first relief pattern with a first solubility converter in block (306), and the step of laminating a first polymer filler on a substrate so that a planar layer is provided in block (308). The first solubility converter and the first polymer filler are as described above. In block (310), the first solubility converter diffuses into the first polymer filler to provide a solubility-converted region of the first polymer filler. The diffusion of the first solubility converter may be performed via soft baking as described above. The solubility-converted region may have a different solubility from the portion of the first polymer filler that is not exposed to the solubility-converting agent. Then, in block (312), the coated substrate may be developed so that the solubility-converted region of the first polymer filler is dissolved and a narrow trench is formed that exposes the target layer. In some embodiments, development includes one or more of exposure to chemical radiation, heat treatment, and development using a specific developer previously described. After developing the substrate and dissolving the solubility-converted region of the first polymer filler, the target layer may be etched using the first polymer filler and the first relief pattern as a combined etching mask to provide a first pattern line (block 314).

[0108] Next, in block (316) of the method (300), a second relief pattern comprising a second resist is provided on the target layer. The second resist is as described above. The second relief pattern may include features separated by gaps, wherein the features are formed orthogonally to the first pattern line. In block (318), the second relief pattern is coated with a second solubility converter as described above. Then, in block (320), a second polymer filler is deposited on the substrate to fill any gap of the second relief pattern where the target layer is exposed. The second polymer filler is as described above. In block (322) of the method (300), the second solubility converter diffuses into the second polymer filler to provide a solubility-converted region as described above. The solubility-converted region may have a different solubility than the portion of the second polymer filler not exposed to the solubility converter. Next, in block (324), the substrate is developed so that a narrow trench is formed in which the region of solubility conversion of the second polymer filler is dissolved and the target layer is exposed. The trench of the second resist layer (i.e., the second polymer filler and the second relief pattern) may intersect the trench of the first resist layer (i.e., the first polymer filler and the first relief pattern). As previously mentioned, various intersection angles (particularly 90° and 60°) may be used for the first trench line. Finally, in block (326), the pattern defined by the second polymer film and the second polymer filler is selectively etched into the target layer. This etching method can prevent etching of thin regions and ensure that etching continues until it stops at the hard mask etching stop layer.

[0109] Alternatively, the final etching step may be specified in the existing thin region, even if throughput is reduced. The method disclosed herein may include any shape depending on the overlapping region. For example, a fully dense contact array may be provided by overlapping two or three different arrays to provide a maximally dense final array. FIG. 4 illustrates a possible shape that can be produced according to the method of one or more embodiments.

[0110] Method (100) represents one possible embodiment and is not intended to limit the scope of the invention. As understood by those skilled in the art, the invention may include various alternative methods, for example, in which a first solubility modifier diffuses into a first resist rather than a first polymer filler, and a second solubility modifier diffuses into a second resist rather than a second polymer filler. In such alternative embodiments, the components and techniques used in the method may be as previously described with reference to Method (100).

[0111] As mentioned above, in one or more embodiments, the first solubility converting agent diffuses into the first resist, and the second solubility converting agent diffuses into the second resist. In such embodiments, the method may include the step of initially forming a first relief pattern of the first resist and then coating the first resist with the first solubility converting agent. At this time, the first solubility converting agent may diffuse into the first resist by a predetermined distance to provide a solubility-converted region of the first resist. The diffusion of the first solubility converting agent may occur with other components at different points of the method, but the diffusion of the solubility converting agent may be performed as described above in the method (100). After the first solubility converting agent diffuses into the first resist, the first polymer filler may be deposited on the substrate. Then, as described above, the second relief pattern may be laminated on the first relief pattern. Subsequently, the second solubility converting agent may be coated on the second relief pattern and then diffused into the second relief pattern. Diffusion of the second solubility converting agent may provide a solubility-converted region or a second resist. Then, a second polymer filler is deposited on the second relief pattern. Finally, the substrate is developed and etched as described with reference to method (100), wherein the solubility-converted regions of the first and second resists are soluble in a specific developer.

[0112] One or more embodiments of a method and system that rely on both chemical processes and diffusion characteristics provide a unique ability to add control functions to the input chemistry itself and a process for measuring such chemistry.

[0113] Embodiments of the present disclosure may provide at least one of the following advantages. A method according to one or more embodiments provides the ability to etch a high-density contact array pattern on a substrate without requiring conventional, expensive lithography steps. Accordingly, a method according to the present disclosure provides a more affordable high-density contact array, such as a memory device. Lithography control is maintained so that a patterned region around the contact array can be formed. Accordingly, track-based or in-resist, spacer-free technology for contact arrays is made possible by the method disclosed herein, thereby eliminating the need for atomic layer deposition (ALD) and etching technologies.

[0114] Although only a few exemplary embodiments have been described in detail above, those skilled in the art will readily understand that many modifications are possible from the exemplary embodiments without substantially departing from the invention. Accordingly, all such modifications are intended to be included within the scope of the disclosure as defined in the following claims.

Claims

Claim 1 A microfabrication method comprising: providing a substrate having a target layer formed thereon; forming a first relief pattern on the substrate, wherein the first relief pattern comprises a first resist; coating the first relief pattern with a first solubility converting agent; stacking a first polymer filler on the first relief pattern; diffusing the first solubility converting agent into the first polymer filler at a predetermined distance to provide a solubility-converted region of the first polymer filler, wherein the solubility-converted region of the first polymer filler is in contact with the first relief pattern and the solubility-converted region of the first polymer filler is soluble in a first developer; forming a second relief pattern on the first relief pattern, wherein the second relief pattern comprises a second resist; coating the second relief pattern with a second solubility converting agent; stacking a second polymer filler on the second relief pattern; diffusing the second solubility converting agent into the second polymer filler at a predetermined distance to provide a solubility-converted region of the second polymer filler A method comprising: a step of providing, wherein the solubility-converted region of the second polymer filler is in contact with the second relief pattern and the solubility-converted region of the second polymer filler is soluble in the second developer; a step of developing the first polymer filler and the second polymer filler so that the solubility-converted region of the first polymer filler and the solubility-converted region of the second polymer filler dissolve to provide a gap between the first relief pattern, the first polymer filler, the second relief pattern, and the second polymer filler, thereby exposing a portion of the target layer; and a step of etching the target layer using the first relief pattern, the first polymer filler, the second relief pattern, and the second polymer filler as a combined etching mask. Claim 2 A microfabrication method comprising: providing a substrate having a target layer formed thereon; forming a first relief pattern on the substrate, wherein the first relief pattern comprises a first resist; coating the first relief pattern with a first solubility converting agent; stacking a first polymer filler on the first relief pattern; diffusing the first solubility converting agent into the first polymer filler at a predetermined distance to provide a solubility-converted region of the first polymer filler, wherein the solubility-converted region of the first polymer filler is in contact with the first relief pattern; developing the first polymer filler so that the solubility-converted region of the first polymer filler dissolves to provide a gap between the first relief pattern and the first polymer filler, wherein a portion of the target layer is exposed; etching the target layer using the first relief pattern and the first polymer filler as a combined etching mask; forming a second relief pattern on the substrate, wherein the second relief pattern comprises a second resist; and using a second solubility converting agent A method comprising: a step of coating a second relief pattern; a step of depositing a second polymer filler on the second relief pattern; a step of diffusing a second solubility converting agent into the second polymer filler at a predetermined distance to provide a solubility-converted region of the second polymer filler, wherein the solubility-converted region of the second polymer filler is in contact with the second relief pattern; a step of developing the second polymer filler so that the solubility-converted region of the second polymer filler dissolves to provide a gap between the second relief pattern and the second polymer filler, wherein a portion of the target layer is exposed; and a step of etching a target layer of a substrate using the second relief pattern and the second polymer filler as a combined etching mask. Claim 3 A method according to claim 1 or 2, wherein the first relief pattern comprises features separated by gaps between features, and said features comprise a first resist. Claim 4 A method according to paragraph 3, wherein the first polymer filler fills the gap of the first relief pattern. Claim 5 A method according to claim 1 or 2, wherein the second relief pattern includes features separated by gaps between features, and said features include a second resist. Claim 6 In paragraph 5, a method in which the second polymer filler fills the gap of the second relief pattern. Claim 7 A method according to claim 1 or 2, wherein the step of etching a substrate includes the step of performing anisotropic etching. Claim 8 A method according to claim 1 or 2, wherein the step of providing a first relief pattern to a target layer comprises: forming a first pattern line on the target layer; depositing a first resist layer on the first pattern line; and exposing the first resist to a pattern of chemical radiation to develop the first resist so that the first relief pattern is formed on the first pattern line. Claim 9 A method according to claim 1 or 2, wherein the first solubility converting agent comprises an acid generating agent. Claim 10 In paragraph 9, a method in which the acid generator is fluorine-free. Claim 11 A method according to claim 9, wherein the acid generating agent is selected from the group consisting of triphenylsulfonium antimonate, pyridinium perfluorobutanesulfonate, 3-fluoropyridinium perfluorobutanesulfonate, 4-t-butylphenyltetramethylenesulfonium perfluoro-1-butanesulfonate, 4-t-butylphenyltetramethylenesulfonium 2-trifluoromethylbenzenesulfonate, 4-t-butylphenyltetramethylenesulfonium 4,4,5,5,6,6-hexafluorodihydro-4H-1,3,2-dithiazine 1,1,3,3-tetraoxide, and combinations thereof. Claim 12 A method according to claim 1 or 2, wherein the first solubility converting agent comprises an acid. Claim 13 In Paragraph 12, a method in which the acid is fluorine-free. Claim 14 A method according to claim 12, wherein the acid is selected from the group consisting of trifluoromethanesulfonic acid, perfluoro-1-butanesulfonic acid, p-toluenesulfonic acid, 4-dodecylbenzenesulfonic acid, 2,4-dinitrobenzenesulfonic acid, 2-trifluoromethylbenzenesulfonic acid, and combinations thereof. Claim 15 A method according to claim 1 or 2, wherein the first solubility converting agent comprises a matrix polymer comprising a monomer having an ethyleneally unsaturated polymerizable double bond, wherein the matrix polymer comprises a (meth)acrylate monomer; (meth)acrylic acid; vinyl aromatic monomers, e.g., styrene, hydroxystyrene, vinyl naphthalene and acenaphtylene; vinyl alcohol; vinyl chloride; vinyl pyrrolidone; vinyl pyridine; vinyl amine; vinyl acetal; maleic anhydride; maleimide; norbornene; and combinations thereof. Claim 16 A method according to claim 1 or 2, wherein the second solubility converting agent comprises an acid generating agent. Claim 17 In Paragraph 16, a method in which the acid-generating agent is fluorine-free. Claim 18 A method according to claim 16, wherein the acid-generating agent is selected from the group consisting of triphenylsulfonium antimonate, pyridinium perfluorobutanesulfonate, 3-fluoropyridinium perfluorobutanesulfonate, 4-t-butylphenyltetramethylenesulfonium perfluoro-1-butanesulfonate, 4-t-butylphenyltetramethylenesulfonium 2-trifluoromethylbenzenesulfonate, 4-t-butylphenyltetramethylenesulfonium 4,4,5,5,6,6-hexafluorodihydro-4H-1,3,2-dithiazine 1,1,3,3-tetraoxide, and combinations thereof. Claim 19 A method according to claim 1 or 2, wherein the second solubility converting agent comprises an acid. Claim 20 In paragraph 19, a method in which the acid is fluorine-free. Claim 21 A method according to claim 19, wherein the acid is selected from the group consisting of trifluoromethanesulfonic acid, perfluoro-1-butanesulfonic acid, p-toluenesulfonic acid, 4-dodecylbenzenesulfonic acid, 2,4-dinitrobenzenesulfonic acid, 2-trifluoromethylbenzenesulfonic acid, and combinations thereof. Claim 22 A method according to claim 1 or 2, wherein the second solubility converting agent comprises a matrix polymer comprising a monomer having an ethyleneally unsaturated polymerizable double bond, wherein the second solubility converting agent comprises a meth)acrylate monomer; (meth)acrylic acid; vinyl aromatic monomers such as styrene, hydroxystyrene, vinyl naphthalene and acenaphtylene; vinyl alcohol; vinyl chloride; vinyl pyrrolidone; vinyl pyridine; vinyl amine; vinyl acetal; maleic anhydride; maleimide; norbornene; and combinations thereof. Claim 23 A method according to claim 1 or 2, wherein the first resist is a positive tone developed resist and the first polymer filler comprises a polymer soluble in a polar solvent. Claim 24 A method according to claim 1 or 2, wherein the first resist is a negative tone developed resist and the first polymer filler comprises a polymer soluble in a non-polar organic solvent. Claim 25 A method according to claim 1 or 2, wherein the first solubility converting agent comprises a solvent. Claim 26 A method according to claim 25, wherein the solvent is selected from the group consisting of methyl isobutyl carbinol (MIBC), decane, isobutyl isobutyrate, isoamyl ether, and combinations thereof. Claim 27 In paragraph 25, the method wherein the first resist is insoluble in a solvent. Claim 28 A method according to claim 1 or 2, wherein the first resist comprises a polymer prepared from a monomer selected from the group consisting of styrene, p-hydroxystyrene, methacrylate, norbornene, and combinations thereof. Claim 29 A method according to claim 1 or 2, wherein the first polymer filler comprises a polymer prepared from a monomer selected from the group consisting of styrene, p-hydroxystyrene, methacrylate, norbornene, and combinations thereof. Claim 30 A method according to paragraph 23, wherein a specific developer is tetramethylammonium hydroxide. Claim 31 A method according to claim 24, wherein a specific developer is a nonpolar organic solvent selected from the group consisting of n-butyl acetate (NBA), 2-heptanone, and combinations thereof. Claim 32 A method according to claim 1 or 2, wherein the second resist is a positive tone developed resist and the second polymer filler comprises a polymer soluble in a polar solvent. Claim 33 A method according to claim 1 or 2, wherein the second resist is a negative tone developed resist and the second polymer filler comprises a polymer soluble in a non-polar organic solvent. Claim 34 A method according to claim 1 or 2, wherein the second solubility converting agent comprises a solvent. Claim 35 A method according to claim 34, wherein the solvent is selected from the group consisting of methyl isobutyl carbinol (MIBC), decane, isobutyl isobutyrate, isoamyl ether, and combinations thereof. Claim 36 A method according to claim 1 or 2, wherein the second resist comprises a polymer prepared from a monomer selected from the group consisting of styrene, p-hydroxystyrene, methacrylate, norbornene, and combinations thereof. Claim 37 A method according to claim 1 or 2, wherein the second polymer filler comprises a polymer prepared from a monomer selected from the group consisting of styrene, p-hydroxystyrene, methacrylate, norbornene, and combinations thereof. Claim 38 In paragraph 32, a method in which a specific developer is tetramethylammonium hydroxide. Claim 39 A method according to claim 33, wherein a specific developer is a nonpolar organic solvent selected from the group consisting of n-butyl acetate (NBA), 2-heptanone, and combinations thereof.

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