In-resist process for high density contact formation.

Abstract

The microfabrication method includes forming a first relief pattern on a target layer of a substrate, coating the first relief pattern with a first solubility modifier, depositing a first polymer fill onto the first relief pattern, and diffusing the first solubility modifier into the first polymer fill to provide a region of altered solubility in the first polymer fill. The method then includes forming a second relief pattern on the first relief pattern, coating the second relief pattern with a second solubility modifier, depositing the second polymer fill onto the second relief pattern, and diffusing the second solubility modifier into the first polymer fill to provide a region of altered solubility in the second polymer fill. Finally, the solubility-altered regions of the first polymer fill and the second polymer fill are developed, and the target layer is etched.

Description

[Background technology]

[0001] Multi-patterning is a term that describes the use of two or more lithographic processes to create the final pattern. Multi-pattering in different forms enables the fabrication of high-performance semiconductor devices. Patterning typically involves two basic steps. The first step involves the use of lithography using mask-based exposure to light followed by development of soluble regions to create the pattern. The second step involves transferring the pattern into the underlying material by directional or anisotropic etching. These two steps together can be referred to as device patterning.

[0002] High-density contact arrays are a defining feature of dynamic access random memory (DRAM) and static random-access memory (SRAM) technologies and are critical for high-performance logic. Conventional multi-patterning processes can form contact arrays across the plane of sidewall spacers. However, sidewall spacer processing is relatively expensive and time-consuming due to the vapor deposition and etching required. Summary of the Invention [Means for solving the problem]

[0003] This Summary is provided to introduce a selection of concepts that are further described below in the Detailed Description. This Summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

[0004] In one aspect, embodiments disclosed herein relate to a method of microfabrication, the method including 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 modifier, and depositing a first polymer fill onto the first relief pattern. The method then includes diffusing the first solubility modifier a predetermined distance into the first polymer fill to provide a solubility-altered region of the first polymer fill, the solubility-altered region of the first polymer fill adjacent to the first relief pattern, and the solubility-altered region of the first polymer fill being soluble in a first developer. A second relief pattern is then formed on the first relief pattern and coated with a second solubility modifier. The method then includes depositing a second polymer fill over the second relief pattern and diffusing the second solubility modification a predetermined distance into the second polymer fill to provide a solubility-altered region of the second polymer fill, the solubility-altered region of the second polymer fill adjacent the second relief pattern, the solubility-altered region of the second polymer fill being soluble in a second developer. Finally, the method includes developing the first polymer fill and the second polymer fill to dissolve the solubility-altered region of the first polymer fill and the solubility-altered region of the second polymer fill, providing gaps between the first relief pattern, the first polymer fill, the second relief pattern, and the second polymer fill, exposing portions of the target layer; and etching the target layer using the first relief pattern, the first polymer fill, the second relief pattern, and the second polymer fill as a combined etch mask.

[0005] In another aspect, embodiments disclosed herein relate to a method of microfabrication, the method including 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 modifier, depositing a first polymer fill over the first relief pattern, diffusing the first solubility modifier a predetermined distance into the first polymer fill to provide a solubility-altered region of the first polymer fill adjacent to the first relief pattern, developing the first polymer fill to dissolve the solubility-altered region of the first polymer fill and provide a gap between the first relief pattern and the first polymer fill exposing a portion of the target layer, and etching the target layer using the first relief pattern and the first polymer fill as a combined etch mask. The method then includes forming a second relief pattern on the substrate, coating the second relief pattern with a second solubility modifier, depositing a second polymer fill over the second relief pattern, and diffusing the second solubility modifier a predetermined distance into the second polymer fill to provide a solubility-altered region of the second polymer fill, the solubility-altered region of the second polymer fill adjacent the second relief pattern. Finally, the method includes developing the second polymer fill to dissolve the solubility-altered region of the second polymer fill to provide a gap between the second relief pattern and the second polymer fill exposing a portion of the target layer, and etching the target layer using the second relief pattern and the second polymer fill as a combined etch mask.

[0006] Other aspects and advantages of the claimed subject matter will become apparent from the following description and appended claims. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a block flow diagram of a method in accordance with one or more embodiments of the present disclosure.

[0008] [Figure 2A] 1A-1D are schematic diagrams of a coated substrate at various points in a method in accordance with one or more embodiments of the present disclosure. [Figure 2B] 1A-1D are schematic diagrams of a coated substrate at various points in a method in accordance with one or more embodiments of the present disclosure. [Figure 2C] 1A-1D are schematic diagrams of a coated substrate at various points in a method in accordance with one or more embodiments of the present disclosure. [Figure 2D] 1A-1D are schematic diagrams of a coated substrate at various points in a method in accordance with one or more embodiments of the present disclosure. [Figure 2E] 1A-1D are schematic diagrams of a coated substrate at various points in a method in accordance with one or more embodiments of the present disclosure. [Figure 2F] 1A-1D are schematic diagrams of a coated substrate at various points in a method in accordance with one or more embodiments of the present disclosure. [Figure 2G] 1A-1D are schematic diagrams of a coated substrate at various points in a method in accordance with one or more embodiments of the present disclosure. [Figure 2H] 1A-1D are schematic diagrams of a coated substrate at various points in a method in accordance with one or more embodiments of the present disclosure. [Figure 2I] 1A-1D are schematic diagrams of a coated substrate at various points in a method in accordance with one or more embodiments of the present disclosure.

[0009] [Figure 3] FIG. 1 is a block flow diagram of a method in accordance with one or more embodiments of the present disclosure.

[0010] [Figure 4] 1A-1C are exemplary schematic diagrams of patterns produced using methods in accordance with one or more embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present disclosure generally relates to a method for multi-patterning a semiconductor substrate. In one or more embodiments, the method includes forming a complex pattern, such as a dense 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, a semiconductor wafer, a layer of semiconductor material, and combinations thereof. The method may include cutting the complex pattern directly onto the substrate.

[0012] The methods disclosed herein eliminate the need for sidewall spacers by intersecting two sides of the 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 creates spacers through the use of a chemical process diffusion using a single exposure. In the methods disclosed herein, two to three anti-spacer processes are used, and high-density contact arrays can be created. Such methods can advantageously create very small contacts at very low cost and with consistent sizes.

[0013] In this disclosure, a method 100 in which two anti-spacer processes are applied to a pattern on a substrate is shown in FIG. 1 and will be discussed with reference to this. Initially, the method 100 includes providing a substrate having a target layer formed thereon in block 102. Then, in block 104, a first relief pattern can be formed on the target layer. The first relief pattern can be formed using a photolithography process and can be made from a first resist. In block 106, the first relief pattern is coated with a first solubility modifier. In certain embodiments, the first solubility modifier is incorporated into the first resist. When the solubility modifier is incorporated into the first resist, a solubility modifier that is a thermal acid generator can be added to the first resist, the solubility modifier having a higher activation temperature than the temperature at which the resist would be processed in the absence of the thermal acid generator. As a result, the solubility modifier can be activated after the photolithography process that forms the first relief pattern. The resulting acid can diffuse from the first resist and change the solubility of the second resist. Then, in block 108, the first polymer fill is deposited onto the substrate, so that all exposed portions of the target layer are covered with the first polymer fill. Deposition of the first polymer fill can also be referred to as "planarizing" the substrate, as this process can provide a flat layer on the surface of the substrate. In block 110, a first solubility-modifying agent is then diffused into the first polymer fill, providing solubility-altered regions of the first polymer fill that are soluble in the first developer.

[0014] In block 112 of method 100, a second relief pattern may be formed on the first relief pattern and the first polymer fill. The second relief pattern may be formed using a photolithography process and may be made from a second resist. In one or more embodiments, the second relief pattern is formed perpendicular to the first relief pattern. In block 114, the second relief pattern is coated with a second solubility modifier. Then, in block 116, a second polymer fill is layered on the second relief pattern to fill any gaps in the first relief pattern, the first polymer fill, or the second relief pattern that expose the target layer. In block 118, the second solubility modifier is diffused into the second polymer fill, providing solubility-altered regions of the second polymer fill that are soluble in a second developer. In block 120, the first polymer fill and the second polymer fill are developed. In block 122, after developing the top surface, the target layer may be etched to form a pattern for a high density contact array.

[0015] Schematic illustrations of a coated substrate at various points during the method are shown in Figures 2A-2I. As used herein, "coated substrate" refers to a substrate that has been coated with one or more layers, such as a first resist layer and a first polymer fill layer. Figure 2A shows a substrate including a target layer and a first relief pattern. Figure 2B shows a substrate including a first relief pattern coated with a first solubility modifier. In Figure 2C, a first polymer fill is layered over the target layer and the first relief pattern. Figure 2D shows a coated substrate in which the first polymer fill has regions of altered solubility provided by diffusing a solubility modifier into the first polymer fill. Switching now to a top view, Figure 2E shows a second relief pattern layered over the first polymer fill, and Figure 2F shows a second relief pattern coated with a second solubility modifier. In Figure 2G, a second polymer fill is layered over the second relief pattern. Figure 2H shows the coated substrate after the second solubility modifier has been diffused into the second polymer fill, providing a second polymer fill including a solubility-altered region. Finally, Figure 2I shows the coated substrate after the solubility-altered regions of the first polymer fill and the solubility-altered regions of the second polymer fill have been developed, thereby exposing portions of the target layer and making them available for etching. The method of Figure 1 and the coated substrates shown in Figures 2A-2I are discussed in more detail below.

[0016] In block 102 of method 100, a target layer is provided on a substrate. The target layer can be any target or storage layer known in the art. In one or more specific embodiments, the target layer is a hard mask layer.

[0017] Next, in block 104, a first relief pattern is provided. FIG. 2A shows an example of a first relief pattern 204 on a target layer 202 of a substrate 201. As shown in FIG. 2A, the first relief pattern can include features separated by gaps. Portions of the substrate can be exposed due to the presence of the gaps in the first relief pattern. The features of the first relief pattern can be created from a first resist 203. The first resist can be a photoresist. Generally, photoresists are chemically amplified photosensitive compositions containing a polymer, a photoacid generator, and a solvent. In one or more embodiments, the first resist includes a polymer. The polymer can be any standard polymer typically used in resist materials, particularly a polymer with acid-labile groups. For example, the polymer can be a polymer made from monomers including styrene and p-hydroxystyrene, acrylates, methacrylates, norbornenes, and combinations thereof. Monomers containing reactive functional groups can be present in the polymer in a protected form. For example, the -OH group of p-hydroxystyrene can be protected with a tert-butyloxycarbonyl protecting group. Such a protecting group can modify the reactivity and solubility of the polymer contained in the first resist. As will be understood by those skilled in the art, various protecting groups can be used for this purpose. Acid labile groups include, for example, tertiary alkyl ester groups, secondary or tertiary aryl ester groups, secondary or tertiary ester groups having a combination of alkyl and aryl groups, tertiary alkoxy groups, acetal groups, or ketal groups. Acid labile groups are also commonly referred to in the art as "acid-decomposable groups," "acid-labile groups," "acid-labile protecting groups," "acid-leaving groups," and "acid-sensitive groups."

[0018] The acid labile groups that upon degradation form carboxylic acids on the polymer preferably have the formula —C(O)OC(R 1 )3, or a tertiary ester group of the formula —C(O)OC(R 2 )2OR 3 where R 1 are each independently a linear C 1-20 Alkyl, branched C3-20 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; and each R 1 optionally includes as part of its structure one or more groups selected from -O-, -C(O)-, -C(O)-O- or -S-, and any two R 1 The groups together optionally form a ring, R 2 are independently hydrogen, fluorine, straight-chain 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 cycloalkyl, each of which is substituted or unsubstituted; and each R 2 optionally includes as part of its structure one or more groups selected from -O-, -C(O)-, -C(O)-O- or -S-, and R 2 The groups together optionally form a ring, R 3 is a linear C 1-20 Alkyl, branched C 3-20 Alkyl, monocyclic or polycyclic C 3-20 Cycloalkyl, linear C 2-20 Alkenyl, branched C 3-20Alkenyl, 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 optionally includes as part of its structure one or more groups selected from -O-, -C(O)-, -C(O)-O- or -S-, and one R 2 is R 3 and optionally form a ring. Such a monomer is typically an aromatic vinyl, (meth)acrylate, or norbornyl monomer. The total content of polymerized units containing acid-decomposable groups that form carboxylic acid groups in 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.

[0019] The polymer may further comprise a monomer that, upon polymerization, contains an acid labile group, the decomposition of which forms an alcohol or fluoroalcohol group on the polymer. Suitable such groups include, for example, those of the formula -COC(R 2 )2OR 3 or a carbonate group of the formula -OC(O)O-, where R is as defined above. Such monomers are typically aromatic vinyl, (meth)acrylate, or norbornyl monomers. When present in the polymer, the total content of polymerized units containing acid-decomposable groups that form alcohol groups or fluoroalcohol groups in the polymer upon decomposition is typically 10 to 90 mol %, more typically 30 to 70 mol %, based on the total polymerized units of the polymer.

[0020] In embodiments where the first resist is a photoresist, the first resist includes a photoacid generator. The photoacid generator is a compound capable of generating an acid upon irradiation with actinic rays or actinic radiation. The photoacid generator can be selected from known compounds capable of generating an acid upon irradiation with actinic rays or radiation, such as those used as photopolymerization initiators for cationic photopolymerization, photopolymerization initiators for radical photopolymerization, photobleachers for dyes, photochromic agents, microresists, etc., and mixtures thereof can also be used. Examples of photoacid generators include diazonium salts, phosphonium salts, sulfonium salts, iodonium salts, imidosulfonates, oximesulfonates, diazodisulfones, disulfones, and o-nitrobenzylsulfonates.

[0021] Suitable photoacids include, for example, onium salts such as triphenylsulfonium trifluoromethanesulfonate, (p-tert-butoxyphenyl)diphenylsulfonium trifluoromethanesulfonate, tris(p-tert-butoxyphenyl)sulfonium trifluoromethanesulfonate, triphenylsulfonium p-toluenesulfonate, di-t-butylphenyliodonium perfluorobutanesulfonate, and di-t-butylphenyliodonium camphorsulfonate. Nonionic sulfonate and sulfonyl compounds can be used as photoacid generators. They are also known to function as a generator, and examples thereof include nitrobenzyl derivatives such as 2-nitrobenzyl-p-toluenesulfonate, 2,6-dinitrobenzyl-p-toluenesulfonate, and 2,4-dinitrobenzyl-p-toluenesulfonate; sulfonate esters such as 1,2,3-tris(methanesulfonyloxy)benzene, 1,2,3-tris(trifluoromethanesulfonyloxy)benzene, and 1,2,3-tris(p-toluenesulfonyloxy)benzene; diazomethane derivatives such as bis(benzenesulfonyl)diazomethane and bis(p-toluenesulfonyl)diazomethane; , glyoxime derivatives such as bis-O-(p-toluenesulfonyl)-α-dimethylglyoxime and bis-O-(n-butanesulfonyl)-α-dimethylglyoxime; sulfonate derivatives of N-hydroxyimide compounds such as N-hydroxysuccinimide methanesulfonate and N-hydroxysuccinimide trifluoromethanesulfonate; and halogen-containing triazine compounds such as 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine and 2-(4-methoxynaphthyl)-4,6-bis(trichloromethyl)-1,3,5-triazine. Suitable non-polymerizable photoacid generators are further described in U.S. Pat. No. 8,431,325 by Hashimoto et al. (columns 37, lines 11-47 and columns 41-91).Other suitable sulfonate PAGs include sulfonated esters and sulfonyloxyketones, nitrobenzyl esters, s-triazine derivatives, benzoin tosylate, t-butylphenyl α-(p-toluenesulfonyloxy)-acetate, and t-butyl α-(p-toluenesulfonyloxy)-acetate, as described in U.S. Patent Nos. 4,189,323 and 8,431,325. PAGs that are onium salts typically contain an anion bearing a sulfonate or non-sulfonate group, such as a sulfonamidate group, a sulfonimidate group, a methide group, or a borate group.

[0022] The resist composition may optionally contain multiple PAGs. The multiple PAGs may be polymeric, non-polymeric, or may include both polymeric and non-polymeric PAGs. Preferably, each of the multiple PAGs is non-polymeric. Preferably, when multiple PAGs are used, a first PAG contains a sulfonate group in the anion, and a second PAG contains an anion that does not contain a sulfonate group, such as a sulfonamidate group, sulfonimidate group, methide group, or borate group as described above.

[0023] The first relief pattern can be formed by laminating a first resist onto a substrate and then developing the first resist. The first resist is developed according to procedures known in the art, such as by exposure to actinic radiation followed by rinsing with a first resist developer. To impart a shape or relief pattern to the developed resist, a mask can be used to block portions of the resist from actinic radiation. After exposure to actinic radiation, the unexposed portions of the resist can have a different solubility than the exposed portions of the resist. Subsequent rinsing with a first resist developer dissolves either the unexposed or exposed portions. When the unexposed portions of the resist remain after rinsing with a developer, the provided relief pattern is a positive-tone developed resist. In contrast, when the exposed portions of the resist remain after rinsing with a developer, the provided relief pattern is a negative-tone developed resist.

[0024] In one or more embodiments, the first resist is a positive tone developed (PTD) resist. In such embodiments, the first relief pattern can include a polymer made from the above-described monomers, with any monomers containing reactive functional groups being protected. As such, the first PTD resist can be organic-soluble, whereby a relief pattern can be provided by rinsing with a basic first resist developer. Suitable basic first resist developers include quaternary ammonium hydroxides, such as tetramethylammonium hydroxide (TMAH).

[0025] Alternatively, in one or more embodiments, the first resist is a negative resist. In such embodiments, the first relief pattern can include a polymer made from the above-mentioned monomers, and any monomers containing reactive functional groups are not protected. Exposure to actinic radiation causes crosslinking of the polymer in the exposed areas, making the polymer insoluble in the developer. The unexposed, and therefore uncrosslinked, areas can then be removed using an appropriate developer to form the relief pattern.

[0026] In other embodiments, the first resist is a negative tone developed (NTD) resist. Similar to PTD resists, NTD resists can include polymers made from the above-described monomers, with any monomers containing reactive functional groups being protected. Thus, the first NTD resist can be organic-soluble, but instead of developing the exposed areas with a basic first resist developer, the first relief pattern can be provided by rinsing the first resist with a first resist developer containing an organic solvent. Suitable organic solvents that can be used as first resist developers include n-butyl acetate (NBA) and 2-heptanone. The tone of the resist (i.e., PTD vs. negative vs. NTD) can affect the subsequent chemistry applied to the first relief pattern. In one or more embodiments, NTD resists are advantageous compared to PTD resists. The resist can be selected to be soluble in a solvent that does not dissolve the underlying pattern.

[0027] In another embodiment, the first resist optionally contains other additives, and the other additives include at least one of a resin having at least either 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 accelerating dissolution in a developer.

[0028] As described above, the first relief pattern can include features separated by gaps. In one or more embodiments, the features of the first relief pattern can have a thickness of about 300 to about 3000 Å. The gaps separating the features can leave portions of the substrate exposed.

[0029] In some embodiments, the first relief pattern is stabilized prior to coating with the solubility modifier. Various resist stabilization techniques, also known as freeze processes, have been proposed, including ion implantation, UV curing, heat curing, thermal curing, and chemical curing. Techniques are described, for example, in U.S. Patent Application Publication Nos. 2008 / 0063985, 2008 / 0199814, and 2010 / 0330503.

[0030] In block 106 of method 100, the first relief pattern is coated with a first solubility modifier. The coated substrate from block 106 is shown in FIG. 2B. The first solubility modifier 205 is shown as a thin coating on the first relief pattern 204. The thickness of the first solubility modifier coating is not particularly limited and can be varied based on the desired high-density contact array pattern. The first solubility modifier can be absorbed into the first resist. The process of absorbing the solubility modifier into the first resist is further described below. Alternatively, the first solubility modifier can be incorporated into the first resist of the first relief pattern. In such an embodiment, no coating is required and the first solubility modifier can be uniformly dispersed throughout the first resist.

[0031] As described above, in one or more embodiments, the first solubility modifier is absorbed into the first relief pattern. Absorption of the first solubility modifier into the first relief pattern can be achieved by a thermal pretreatment, such as a bake. The bake can be a soft bake. The temperature and time of the soft bake can depend on the properties of the first resist and the desired amount of diffusion of the solubility modifier into the first resist. Typically, the soft bake can be performed at a temperature ranging from about 50° C. to about 150° C. for about 30 to 90 seconds.

[0032] 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 inactive form, so as not to alter the solubility of the first resist. The first solubility modifier can then be activated later in the method 100 to activate and induce the desired solubility change in the desired material.

[0033] The composition of the first solubility modifier can depend on the tone of the first resist. Generally, the first solubility modifier can be any chemical that is activated using light or heat. For example, when the first resist is a PTD resist, the first solubility modifier can include an acid or a thermal acid generator (TAG). The acid, or in the case of a TAG, the generated acid, must be sufficient to cause, by heat, the decomposition of the acid-labile bonds of the polymer in the surface region of the first resist pattern to increase the solubility of the first resist polymer in the particular developer being applied. The acid or TAG is typically present in the composition in an amount of about 0.01 to 20 wt. % based on the total solids content of the trimming composition.

[0034] Preferred acids are organic acids, including non-aromatic or aromatic acids, each of which may optionally have fluorine substitution. Suitable organic acids include, for example, carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, dichloroacetic acid, trichloroacetic acid, perfluoroacetic acid, perfluorooctanoic acid, oxalic acid, alkanoic acids including malonic acid and succinic acid, hydroxyalkanoic acids such as citric acid, aromatic carboxylic acids such as benzoic acid, fluorobenzoic acid, hydroxybenzoic acid and naphthoic acid, organic phosphoric acids such as dimethylphosphoric acid and dimethylphosphinic acid, and 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.

[0035] Exemplary fluorine-free aromatic acids include aromatic acids of the following general formula (I):

[0036] [ka]

[0037] [wherein 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, sulfonamide, ether, thioether, substituted or unsubstituted alkylene group, or a combination thereof; Z1 independently represents a group selected from carboxyl, hydroxy, nitro, cyano, C1-C5 alkoxy, formyl, and sulfonic acid; a and b independently represent integers of 0 to 5, and a+b is 5 or less.]

[0038] An exemplary aromatic acid may be of the following general formula (II):

[0039] [ka]

[0040] [wherein 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, sulfonamide, ether, thioether, substituted or unsubstituted alkylene group, or a combination thereof; Z2 and Z3 each independently represent a group selected from carboxyl, hydroxy, nitro, cyano, C1-C5 alkoxy, formyl, and sulfonic acid; c and d independently represent integers of 0 to 4, and c+d is 4 or less; and e and f independently represent integers of 0 to 3, and e+f is 3 or less]

[0041] Additional aromatic acids that may be included in the solubility modifier include those of the general formula (III) or (IV) below:

[0042] [ka]

[0043] [wherein 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, sulfonamide, ether, thioether, 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 independently represent integers of 0 to 4, and g+h is 4 or less; i and j independently represent integers of 0 to 2, and i+j is 2 or less; k and 1 independently represent integers of 0 to 3, and k+l is 3 or less]

[0044] [ka]

[0045] [wherein 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, sulfonamide, ether, thioether, substituted or unsubstituted alkylene group, or a combination thereof; Z4, Z5, and Z6 independently represent a group selected from carboxyl, hydroxy, nitro, cyano, C1-C5 alkoxy, formyl, and sulfonic acid; g and h independently represent integers of 0 to 4, and g+h is 4 or less; i and j independently represent integers of 0 to 1, and i+j is 1 or less; and k and l independently represent integers of 0 to 4, and k+l is 4 or less]

[0046] Suitable aromatic acids may alternatively be of the following general formula (V):

[0047] [ka]

[0048] [wherein 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, sulfonamide, ether, thioether, substituted or unsubstituted alkylene group, or a combination thereof; Z7 and Z8 each independently represent a group selected from hydroxy, nitro, cyano, C1-C5 alkoxy, formyl, and sulfonic acid; m and n each independently represent an integer of 0 to 5, and m+n is 5 or less; and o and p each independently represent an integer of 0 to 4, and o+p is 4 or less]

[0049] Further, exemplary aromatic acids can have the following general formula (VI):

[0050] [ka]

[0051] wherein 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, sulfonamide, ether, thioether, substituted or unsubstituted alkylene group, or a combination thereof; Z9 independently represents a group selected from carboxyl, hydroxy, nitro, cyano, C1-C5 alkoxy, formyl, and sulfonic acid; and q and r independently represent integers of 0 to 3, and q+r is 3 or less.

[0052] In one or more embodiments, the acid is a free acid with fluorine substitution. Suitable free acids with fluorine substitution can be aromatic or non-aromatic. For example, free acids with fluorine substitution that can be used as solubility modifiers include, but are not limited to:

[0053] [ka] [ka]

[0054] [ka] [ka] [ka] [ka]

[0055] Suitable TAGs include those capable of generating non-polymerizable acids as described above. The TAGs can be non-ionic or ionic. Suitable non-ionic thermal acid generators include, for example, cyclohexyl trifluoromethylsulfonate, methyl trifluoromethylsulfonate, cyclohexyl p-toluenesulfonate, methyl p-toluenesulfonate, cyclohexyl 2,4,6-triisopropylbenzenesulfonate, nitrobenzyl esters, 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, Examples of suitable ionic thermal acid generators include phthalic acid, phosphoric acid, camphorsulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, triisopropylnaphthalenesulfonic acid, 5-nitro-o-toluenesulfonic acid, 5-sulfosalicylic acid, 2,5-dimethylbenzenesulfonic acid, 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, as well as combinations thereof. Suitable ionic thermal acid generators include, for example, dodecylbenzenesulfonic acid triethylamine salt, dodecylbenzenedisulfonic acid triethylamine salt, p-toluenesulfonic acid ammonium salt, p-toluenesulfonic acid pyridinium salt, sulfonates such as carbocyclic aryl and heteroaryl sulfonates, aliphatic sulfonates, and benzenesulfonates. Compounds that generate sulfonic acid upon activation are generally suitable. Preferred thermal acid generators include ammonium p-toluenesulfonate and heteroarylsulfonates.

[0056] Preferably, the TAG is ionic in the reaction scheme for generating sulfonic acid as shown below.

[0057] [ka]

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

[0059] (BH) + (I)

[0060] This is the monoprotonated form of the nitrogen-containing base B. Suitable nitrogen-containing bases B include, for example, ammonia, difluoromethylammonia, optionally substituted amines such as C1-20 alkylamines and C3-30 arylamines, nitrogen-containing heteroaromatic bases such as pyridine or substituted pyridines (e.g., 3-fluoropyridine), pyrimidines and pyrazines, and nitrogen-containing heterocyclic groups such as oxazole, oxazoline, or thiazoline. The aforementioned nitrogen-containing base B can 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] The base B typically has a pKa of 0-5.0, 0-4.0, 0-3.0, or 1.0-3.0. As used herein, terms such as "pKa" are used in accordance with their art-recognized meaning. That is, pKa is the pH of the conjugate acid (BH) of the basic moiety (B) in aqueous solution at about room temperature. + is the negative logarithm (to the base 10) of the dissociation constant of . In certain embodiments, base B has a boiling point of less than about 170°C, less than about 160°C, less than 150°C, less than 140°C, less than 130°C, less than 120°C, less than 110°C, less than 100°C, or less than 90°C.

[0062] Suitable exemplary nitrogen-containing cations (BH) + As for NH4 + , CF2HNH2 +, CF3CH2NH3 + , (CH3)3NH + , (C2H5)3NH + , (CH3)2(C2H5)NH + and the following:

[0063] [ka]

[0064] wherein Y is alkyl, preferably methyl or ethyl.

[0065] In certain embodiments, the solubility modifier can be an acid such as trifluoromethanesulfonic acid, perfluoro-1-butanesulfonic acid, p-toluenesulfonic acid, 4-dodecylbenzenesulfonic acid, 2,4-dinitrobenzenesulfonic acid, and 2-trifluoromethylbenzenesulfonic acid; an acid generator such as 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, when the first resist is an NTD resist, the first solubility modifier may include a base or base generator. In such embodiments, suitable solubility modifiers 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, alicyclic amines, aromatic amines, and heterocyclic amines. Amines can be primary, secondary, or tertiary amines. Amines can be monoamines, diamines, or polyamines. Suitable amines can include C1-30 organic amines, imines, or amides, or C1-30 quaternary ammonium salts of strong bases (e.g., hydroxides or alkoxides) or weak bases (e.g., carboxylates). Exemplary bases include amines such as tripropylamine, dodecylamine, tris(2-hydroxypropyl)amine, tetrakis(2-hydroxypropyl)ethylenediamine, arylamines such as diphenylamine, triphenylamine, aminophenol, and 2-(4-aminophenyl)-2-(4-hydroxyphenyl)propane, Troeger's base, hindered amines such as diazabicycloundecene (DBU) or diazabicyclononene (DBN), amides such as tert-butyl 1,3-dihydroxy-2-(hydroxymethyl)propan-2-ylcarbamate and tert-butyl 4-hydroxypiperidine-1-carboxylate, or ionic quenchers including quaternary alkylammonium salts such as 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 (e.g., hydroxymethyl, hydroxyethyl, and hydroxybutyl), each having 1 to about 8 carbon atoms, preferably 1 to about 5 carbon atoms. Specific examples of hydroxyamines include monoethanolamine, diethanolamine, triethanolamine, 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] A suitable base generator may be a thermal base generator, which forms a base upon heating above a first temperature, typically above about 140° C. The thermal base generator may include functional groups such as amides, sulfonamides, imides, imines, O-acyloximes, benzoyloxycarbonyl derivatives, quaternary ammonium salts, nifedipine, carbamates, and combinations thereof. Exemplary thermal base generators include o-{(β-(dimethylamino)ethyl)aminocarbonyl}benzoic acid, o-{(γ-(dimethylamino)propyl)aminocarbonyl}benzoic acid, 2,5-bis{(β-(dimethylamino)ethyl)aminocarbonyl}terephthalic acid, 2,5-bis{(γ-(dimethylamino)propyl)aminocarbonyl}terephthalic acid, 2,4-bis{(β-(dimethylamino)ethyl)aminocarbonyl}isophthalic acid, 2,4-bis{(γ-(dimethylamino)propyl)aminocarbonyl}isophthalic acid, and combinations thereof.

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

[0069] Suitable organic solvents for the solubility modifier composition include, 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; n-heptane aliphatic hydrocarbons such as n-nonane, n-octane, n-decane, 2-methylheptane, 3-methylheptane, 3,3-dimethylhexane, and 2,3,4-trimethylpentane, as well as fluorinated aliphatic hydrocarbons such as perfluoroheptane; 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 3-methyl-1-butanol, 1-pentanol, 2-pentanol, 4-methyl-2-pentanol, 1-hexanol, 1-hexane, linear, branched or cyclic C4-C9 monohydric alcohols such as 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 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 mixtures containing one or more of these solvents.

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

[0071] When the first resist is formed from an aromatic vinyl-based polymer, as is typical for KrF and EUV photoresists, and the resist is to be developed as a PTD resist, the solvent system preferably includes one or more nonpolar organic solvents. The term "nonpolar organic system" means that the solvent system includes more than 50 wt. % total nonpolar organic solvents based on the total solvents in the solubility modifier composition, and more typically, more than 70 wt. %, more than 85 wt. %, or 100 wt. % total nonpolar organic solvents based on the total solvents in the solubility modifier composition. The nonpolar organic solvents are typically present in the solvent system in a total 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, with those having a total carbon number of 6 to 16 being particularly preferred. Suitable alkyl monoethers include, for example, 1,4-cineole, 1,8-cineole, 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, ethyl benzyl ether, diphenyl ether, dibenzyl ether, and phenetole, 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 such as 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, which for certain compositions may provide enhanced solubility for the solid components of the composition. Suitable alcohol solvents include, for example, linear, branched or cyclic C alcohols such as 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. 4-9Monohydric alcohols and C 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 5-9 The alcohol solvent is preferably C 4-9 The monohydric alcohol is preferably 4-methyl-2-pentanol. Suitable ester solvents include, for example, alkyl esters having a total carbon number of 4 to 10, 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. When used in the solvent system, one or more alcohol solvents and / or ester solvents are typically present in a total amount of 2 to 50 wt. %, more typically 2 to 30 wt. %, based on the solvent system.

[0074] The solvent system can also include one or more additional solvents selected from, for example, one or more of ketones such as 2,5-dimethyl-4-hexanone and 2,6-dimethyl-4-heptanone, and polyethers such as dipropylene glycol monomethyl ether and tripropylene glycol monomethyl ether. If used, such additional solvents are typically present in a total amount of 1 to 20% by weight based on the solvent system.

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

[0076] As described above, in one or more embodiments, the first solubility modifier is coated onto the first relief pattern. To properly coat the first relief pattern, the first solubility modifier can include a matrix polymer. Any matrix polymer commonly used in the art can be included in the first solubility modifier. The matrix polymer must have good solubility in a solvent that does not dissolve the first resist. The matrix polymer can be formed from one or more monomers selected from monomers having an ethylenically unsaturated polymerizable double bond, such as (meth)acrylate monomers such as isopropyl (meth)acrylate and n-butyl (meth)acrylate; (meth)acrylic acid; aromatic vinyl monomers such as styrene, hydroxystyrene, vinyl naphthalene, and acenaphthylene; vinyl alcohol; vinyl chloride; vinyl pyrrolidone; vinyl pyridine; vinyl amine; vinyl acetal; maleic anhydride; maleimide; norbornene; and combinations thereof.

[0077] In some embodiments, the polymer contains one or more functional groups selected from acid groups such as hydroxy, carboxyl, sulfonic acid, and sulfonamide groups, silanols, fluoroalcohols such as hexafluoroisopropyl alcohol [—C(CF3)2OH], anhydrides, lactones, esters, ethers, allylamines, pyrrolidones, and combinations thereof. The polymer can be a homopolymer or a copolymer having multiple distinct repeating units, such as two, three, four, or more repeating units. In one aspect, the repeating units of the polymer are formed entirely from (meth)acrylate monomers, formed entirely from aromatic (vinyl) monomers, or formed entirely from (meth)acrylate monomers and aromatic (vinyl) monomers. When 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 can be t-butyl acrylate (TBA) / p-hydroxystyrene (PHS) copolymer, butyl acrylate (BA) / PHS copolymer, TBA / methacrylic acid (MAA) copolymer, BA / MAA copolymer, PHS / methacrylate (MA) copolymer, and combinations thereof.

[0079] The solubility modifier composition typically contains a single polymer, but can optionally contain one or more additional polymers. The amount of polymer in the composition depends, for example, on the target thickness of the layer; when a thicker layer is desired, a higher polymer content is used. The polymer is typically present in the pattern solubility modifier composition in an amount of 80 to 99.9 wt. %, more typically 90 to 99 wt. %, or 95 to 99 wt. %, based on the total solids content of the solubility modifier composition. The weight average molecular weight (Mw) of the polymer is typically less than 400,000, preferably 3000 to 50,000, more preferably 3000 to 25,000, as measured by GPC relative to polystyrene standards. Typically, the polymer has a polydispersity index (PDI=Mw / Mn) of 3 or less, preferably 2 or less, as measured by GPC relative to polystyrene standards.

[0080] Suitable polymers for use in the solubility modifier composition are commercially available and / or can be easily prepared by those skilled in the art. For example, the polymer can be synthesized by dissolving selected monomers corresponding to the units of the polymer in an organic solvent, adding a radical polymerization initiator, and conducting thermal polymerization to form the polymer. Examples of suitable organic solvents that can be used to polymerize 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'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, and lauroyl peroxide.

[0081] The solubility modifier containing the matrix polymer can be coated onto the first relief pattern according to methods known in the art. Typically, the solubility modifier containing the matrix polymer can be coated onto the first relief pattern by spin coating. The solids content of the first solubility modifier can be adjusted to provide a film of the desired thickness of the first solubility modifier on the first relief pattern. For example, the solids content of the first solubility modifier solution can be adjusted to provide a desired film thickness based on the particular coating equipment utilized, the viscosity of the solution, the speed of the coating tool, and the spin time. 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 agent (i.e., an acid, an acid generator, a base, or a base generator), a solvent, and a matrix polymer, as described above. A typical formulation of such a solubility modifier may comprise about 1-10 wt. % solids and 90-99.9 wt. % solvent, based on the total weight of the solubility modifier, with the solids comprising the active agent and the matrix polymer. Within the solids content, the active agent may be present in an amount ranging from about 1 to about 5 wt. %.

[0083] The first solubility modifier may contain additives with various purposes, depending on the particular chemistry used. In some embodiments, surfactants may be included in the solubility modifier. Surfactants may be included in the solubility modifier to aid in coating quality, particularly when thin gaps between features of the first resist need to be filled. Suitable surfactants known in the art may be included in the solubility modifier.

[0084] After absorption into the first relief pattern, the coating layer, which does not contain any effective solubility modifier, 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 the coated substrate with a solvent that dissolves the coating layer but not the first resist. Rinsing may be performed using a suitable method, for example, by immersing the substrate in a bath filled with solvent for a certain period of time (immersion method), by allowing the solvent to rise to the substrate surface by the action of surface tension and allowing it to stand for a certain period of time, thereby dissolving the coating layer (puddle method), by spraying the solvent onto the substrate surface (spray method), or by continuously spraying the solvent onto a substrate rotating at a constant speed while scanning a solvent-jet nozzle at a constant speed (dynamic dispense method).

[0085] At block 108 of method 100, a first polymer fill is deposited on the substrate. The laminated coated substrate with a first relief pattern 204, a first solubility modifier 205, and a first polymer fill 206 are shown in FIG. 2C. The first polymer fill may be deposited on the substrate, filling gaps in the first relief pattern and being in contact with the first relief pattern or the first solubility modifier. When the first polymer fill is deposited in this manner, a planar layer is present on the substrate and the target layer, as shown in FIG. 2C. In some embodiments, the first polymer fill completely covers the target layer, the first relief pattern, and the first solubility modifier. The first polymer fill may be deposited on the substrate according to any suitable method known in the art, such as spin-on deposition or vapor-phase processing.

[0086] In one or more embodiments, the first polymer fill comprises a resist. In such embodiments, the resist can be a PTD resist, a negative resist, or an NTD resist, as described above. The resist included in the first polymer fill can comprise a polymer. Suitable polymers can be as described above with respect to the polymers defined as the first resist polymer and / or the matrix polymer. In certain embodiments, suitable polymers can be made from monomers including p-hydroxystyrene, styrene, t-butyl acrylate, and combinations thereof. In certain embodiments, the polymer can be made from all three of p-hydroxystyrene, styrene, and t-butyl acrylate. Such polymers can 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, the polymerization reaction to produce the polymer contained in the first polymer charge may include p-hydroxystyrene in an amount ranging from a lower limit of one of about 50%, about 55%, about 60%, and about 65%, to an upper limit of one of about 65%, about 70%, about 75%, and about 80%, where any lower limit may be paired with any mathematically compatible upper limit, and styrene and t-butyl acrylate in an amount ranging from a lower limit of one of about 10%, about 12%, about 14%, about 16%, about 18%, and about 20%, to an upper limit of about 20%, about 22%, about 24%, about 26%, about 28%, and about 30%, where any lower limit may be paired with any mathematically compatible upper limit.

[0087] The polymer contained in the first polymer charge can have a weight average molecular weight (Mw) in the range of 1 to 100 kg / mol. For example, in one or more embodiments, the first polymer charge can include polymers having Mw ranging from lower limits of 1 kg / mol, 2 kg / mol, 5 kg / mol, 10 kg / mol, 15 kg / mol, 20 kg / mol, and 25 kg / mol to upper limits of 25 kg / mol, 50 kg / mol, 75 kg / mol, 80 kg / mol, 90 kg / mol, and 100 kg / mol, where any lower limit can be paired with any mathematically compatible upper limit. Polymers having such Mw can exhibit desirable dissolution properties, particularly dissolution rate.

[0088] In one or more embodiments, the first polymer fill comprises a solvent. The solvent is as described above with respect to the solvent contained in the first solubility modifier. In certain embodiments, the solvent in the first polymer fill is the same as the solvent in the first solubility modifier.

[0089] The first polymer fill may contain additives with various purposes, depending on the particular chemistry used. In some embodiments, a quencher is included in the first polymer fill. The quencher may be included in the first polymer fill to help control the diffusion of the active agent in the solubility modifier. Suitable quenchers include any of the bases previously listed for the solubility modifier.

[0090] At block 110 of method 100, the first solubility modifier is diffused into the first polymer fill. The first solubility modifier may be diffused according to any suitable diffusion method known in the art, although the specific method and conditions used may vary depending on the characteristics of the first solubility modifier, such as activation temperature, diffusivity, etc., among others. In one or more embodiments, the diffusion of the first solubility modifier into the first polymer fill is achieved by baking. The bake may be performed on a hot plate or in an oven. The bake temperature and time may depend on the characteristics of the first polymer fill and the desired amount of diffusion of the first solubility modifier into the first polymer fill. Suitable conditions for baking may include a temperature ranging from 50°C to 160°C and a time ranging from about 30 to 90 seconds. In one or more embodiments, after baking, a solubility-altered region may be present around the edge of the first polymer fill. The amount of diffusion of the first solubility modifier may correspond to the thickness of the solubility-altered region. In some embodiments, the altered solubility region extends into the first polymer filler and has a thickness of about 5 nm to about 60 nm. For example, the thickness of the altered solubility region can range from a lower limit of about 5 nm, about 10 nm, about 15 nm, about 20 nm, and about 25 nm to an upper limit of about 40 nm, about 45 nm, about 50 nm, about 55 nm, and about 60 nm, where any lower limit can be paired with any mathematically compatible upper limit. In one or more embodiments, the thickness of the altered solubility region can correspond to the desired pattern of the high-density contact array to be cut into the target layer.

[0091] A coated substrate including a solubility-altered region of the first polymer fill is shown in FIG. 2D. As shown in FIG. 2D, the coated substrate includes a substrate 201 and a target layer 202. The substrate is as previously described. A first relief pattern 204 composed of a first resist 203 is on the surface of the substrate 202. The first relief pattern 204 is coated with a first solubility modifier. A first polymer fill 206 is coated on the substrate, covering the target layer 201 and forming a planar layer with the first relief pattern 204. In an alternative embodiment, the first polymer fill completely covers the target layer and the first relief pattern. A solubility-altered region 208 of the first polymer fill is shown adjacent to the first relief pattern.

[0092] The solubility-altered regions may have a different solubility than regions of the first polymer fill that were not exposed to the first solubility-modifying agent. Thus, the solubility-altered and unexposed regions of the first polymer fill may be soluble in different resist developers.

[0093] In block 112 of method 100, a second relief pattern 210 may be formed on the first relief pattern and the first polymer film. Herein, the planar layer formed by the first polymer film and the first relief pattern may be referred to as the "lower surface." An external view of the coated substrate including the lower surface and the second relief pattern is shown in FIG. 2E. As shown in FIG. 2E, the second relief pattern may be formed perpendicular to the first relief pattern. In one or more embodiments, the second relief pattern may have features similar to the first relief pattern, separated by gaps, and the features of the second relief pattern may be formed but intersect with the features of the first relief pattern. For example, if the first relief pattern is made of horizontal lines, the second relief pattern may be made of vertical lines such that the lines intersect. In one or more embodiments, the features of the first relief pattern and the second relief pattern may intersect at 90 degrees. In other embodiments, the features may intersect at 60 degrees. As will be appreciated by those skilled in the art, various angles of intersection 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 photolithographically formed and made from a second resist. The second resist can include a polymer. Suitable polymers that can be included in the second resist are as previously described with respect to the first resist. The second resist can be a PTD resist or an NTD resist, as described with respect to the first resist. In one or more embodiments, the second resist is similar to the first resist. To form the second relief pattern without affecting the first relief pattern, a "freeze" can be applied to the first relief pattern. A freeze is a surface treatment that protects the first relief pattern and prevents it from diffusing into the second resist by maintaining the integrity of the feature boundaries.

[0095] In block 114, the second relief pattern is coated with a second solubility modifier. FIG. 2F shows a coated substrate including a lower surface and a second relief pattern coated with a second solubility modifier 212. The second solubility modifier can be similar to the first solubility modifier, insofar as components of the first solubility modifier can also be included in the second solubility modifier. In one or more embodiments, the second solubility modifier includes an acid or acid generator and a matrix polymer, as described above. Furthermore, like the first solubility modifier, the second solubility modifier can be absorbed into the second relief pattern. Alternatively, the second solubility modifier can be formulated into a second resist, as described above with respect to the first solubility modifier.

[0096] The second solubility modifier can be coated onto the second relief pattern by spin coating. The solids content of the second solubility modifier is determined by the amount of matrix polymer included, but can be adjusted to provide a film of the desired thickness of the second solubility modifier on the second relief pattern. For example, the solids content of the solubility modifier solution can be adjusted to provide a desired film thickness based on the particular coating equipment utilized, the viscosity of the solution, the speed of the coating tool, and the spin time. Typical thicknesses of the composition are about 200 Å to about 1500 Å.

[0097] As described above, in one or more embodiments, the second solubility modifier is absorbed into the second relief pattern. Absorption of the solubility modifier into the first relief pattern can be achieved by a thermal pretreatment, such as a bake. The bake can be a soft bake. The temperature and time of the soft bake can depend on the properties of the first resist and the desired amount of diffusion of the solubility modifier into the first resist. Typically, the soft bake can be performed at a temperature ranging from about 50°C to about 150°C for about 30 to 90 seconds.

[0098] After absorption into the first relief pattern, the coating layer, which does not contain any effective solubility modifier, 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 the coated substrate with a solvent that dissolves the coating layer but not the first resist. Rinsing may be performed using a suitable method, such as by immersing the substrate in a bath filled with solvent for a certain period of time (immersion method), by allowing the solvent to rise to the substrate surface under the action of surface tension and then allowing it to stand for a certain period of time, thereby dissolving the coating layer (puddle method), by spraying the solvent onto the substrate surface (spray method), or by continuously spraying the solvent onto a substrate rotating at a constant speed while scanning a solvent-jet nozzle at a constant speed (dynamic dispense method).

[0099] Then, at block 116 of method 100, a second polymer film is deposited over the second relief pattern. An example of a substrate coated at this point in the method is shown in FIG. 2G. As shown in FIG. 2G, a second polymer fill 214 may contact the second relief pattern or the second solubility modifier and may fill any gaps in the second relief pattern that expose the lower surface. Similar to the deposition of the first polymer film, the deposition of the second polymer film may provide a planar layer on the surface of the lower surface. As previously mentioned, such a layer may be referred to as the upper surface.

[0100] In one or more embodiments, the second polymer fill comprises a resist including a polymer and a solvent, and one or more additives as described above with respect to the first polymer fill. In some embodiments, the second polymer fill is the same as the first polymer fill.

[0101] At block 118 of the method 100, the second solubility modifier is diffused into the second polymer fill. In one or more embodiments, the diffusion of the second solubility modifier into the second polymer fill is achieved by performing a bake. The bake may be a soft bake. As described above with respect to the first polymer fill, the temperature and time of the soft bake may depend on the properties of the first polymer fill and the desired amount of diffusion of the second solubility modifier into the second polymer fill.

[0102] After soft baking, the altered solubility region may be present around the edge of the second polymer fill. FIG. 2H shows the coated substrate after the second solubility modifier has diffused into the second polymer fill, providing a second polymer fill including an altered solubility region 216. The amount of diffused second solubility modifier may correspond to the thickness of the altered solubility region. In some embodiments, the altered solubility region extends into the second polymer fill and has a thickness of about 5 nm to about 60 nm. For example, the thickness of the altered solubility region may range from a lower limit of one of 5 nm, 10 nm, 15 nm, 20 nm, and 25 nm to an upper limit of one of 40 nm, 45 nm, 50 nm, 55 nm, and 60 nm, where any lower limit may be paired with any mathematically compatible upper limit. In one or more embodiments, the thickness of the altered solubility region may correspond to the desired pattern of the high-density contact array to be cut into the target layer.

[0103] The solubility-altered regions may have a different solubility than the regions of the second polymer fill that were not exposed to the solubility-modifying agent. Thus, the solubility-altered and unexposed regions of the second polymer fill may be soluble in different resist developers.

[0104] In block 120 of method 100, the first polymer fill and the second polymer fill can be developed using a specific developer to remove the areas of the second polymer fill and the first polymer fill where the solubility has changed. Depending on the resist of each of the first polymer fill and the second polymer fill, the development can include further exposure to actinic radiation, thermal treatment, and development with the specific developer. In one or more embodiments, the first fill and the second fill are developed by first exposing them to actinic radiation and then exposing them to the specific developer. In other embodiments, the first polymer fill and the second polymer fill are only exposed to the specific developer. The specific developer can depend on the tone of the resist present in the first polymer fill and the second polymer fill. In certain embodiments, the first polymer fill and the second polymer fill have the same solubility characteristics, which allows them to be developed with the same specific developer. For example, if the first polymer fill and the second polymer fill comprise a positive-tone development resist, the specific developer can be a base, such as tetramethylammonium hydroxide. On the other hand, if the first polymer fill and the second polymer fill are negative tone development resists, the specific developer may be a non-polar organic solvent such as n-butyl acetate or 2-heptanone.

[0105] As previously described, the thickness of the altered solubility regions can correspond to the desired pattern of the 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 polymer fill 206 and the second polymer fill 214 are each developed to dissolve the altered solubility regions formed on the boundaries of the first and second relief patterns. The result is a crisscross pattern of very narrow trenches that, when combined, define sub-resolution contact openings 220 that expose the target layer 202. Therefore, referring back to FIG. 1 , block 122 of method 100 includes etching the exposed portions of the target layer using the first relief pattern, the first polymer fill, the second relief pattern, and the second polymer fill as a combined etch mask. Such a method can provide a high-density contact array on the target layer. The etching process can be an isotropic or an anisotropic etching process using any suitable dry etchant, such as CF, O, HBr, or F. In one embodiment, the etchant can be a dry etchant such as CF, O, HBr, and F.

[0106] 1 , it will be understood that in a variation of method 100, further developing and etching can occur after diffusing the first solubility modifier, such that developing and etching occur after each of the first and second solubility modifiers. Thus, in one or more embodiments, a first pattern of lines can be etched into a target layer on a substrate, followed by etching a second, perpendicular pattern of lines into the substrate. For example, a method 300 according to such an embodiment of the present disclosure is shown in and discussed with respect to FIG. 3 .

[0107] In FIG. 3 , in block 302, a target layer is provided on a substrate. In one or more embodiments, the target layer is a hard mask layer. A first relief pattern can then be formed on the target layer in block 304. The first relief pattern can include features separated by gaps, resulting in portions of the target layer being exposed. The first relief pattern can include a first resist, as described above. The method 300 then includes coating the first relief pattern with a first solubility modifier in block 306 and depositing a first polymer fill on the substrate to provide a planar layer in block 308. The first solubility modifier and the first polymer fill are as described above. In block 310, the first solubility modifier is diffused into the first polymer fill to provide regions of altered solubility in the first polymer fill. The diffusion of the first solubility modifier can be performed by a soft bake, as described above. The solubility-altered regions may have a different solubility than the portion of the first polymer fill that was not exposed to the solubility-modifying agent. Then, in block 312, the coated substrate may be developed, dissolving the solubility-altered regions of the first polymer fill and forming narrow trenches that expose the target layer. In some embodiments, developing includes one or more of exposure to actinic radiation, thermal treatment, and development with the specific developers described above. After developing the substrate and dissolving the solubility-altered regions of the first polymer fill, the target layer may be etched using the first polymer fill and the first relief pattern as a combined etch mask to provide a first pattern of lines (block 314).

[0108] Thereafter, in block 316 of method 300, a second relief pattern including a second resist is provided on the target layer. The second resist is as described above. The second relief pattern can include features separated by gaps, where the features are formed perpendicular to the first pattern of lines. In block 318, the second relief pattern is coated with a second solubility modifier, as described above. Then, in block 320, a second polymer fill is deposited onto the substrate, filling any gaps in the second relief pattern where the target layer is exposed. The second polymer fill is as described above. In block 322 of method 300, the second solubility modifier is diffused into the second polymer fill to provide a solubility-altered region, as described above. The solubility-altered region can have a different solubility than a portion of the second polymer fill that was not exposed to the solubility modifier. Then, in block 324, the substrate is developed, dissolving the altered solubility areas of the second polymer fill and forming narrow trenches that expose the target layer. The trenches from the second layer of resist (i.e., the second polymer fill and the second relief pattern) may intersect with the trenches from the first layer of resist (i.e., the first polymer fill and the first relief pattern). As noted above, various angles of intersection relative to the first trench lines can be used (90° and 60°, among others). Finally, in block 326, the pattern defined by the second polymer film and the second polymer fill is selectively etched into the target layer. Such an etching method avoids etching thin areas and ensures that etching continues until it stops at the hard mask etch stop layer.

[0109] Alternatively, the final etching step can be specific to the existing thinned region, albeit at a reduced throughput. The methods disclosed herein can include any shape depending on the overlap area. For example, a sufficiently dense array of contacts can be provided by overlapping two or three different arrays, resulting in the densest final array. Figure 4 shows possible shapes 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 invention. As will be appreciated by those skilled in the art, the invention may encompass various alternative methods, such as, for example, a method in which a first solubility modifier is dispersed in a first resist rather than a first polymer fill, and a second solubility modifier is dispersed in a second resist rather than a second polymer fill. In such alternative embodiments, the components and techniques used in the method may be as described above with respect to method 100.

[0111] As described above, in one or more embodiments, a first solubility modifier is diffused into a first resist and a second solubility modifier is diffused into a second resist. In such embodiments, a method may include first forming a first relief pattern in the first resist and then coating the first resist with a first solubility modifier. At this point, the first solubility modifier may diffuse into the first resist a predetermined distance to provide a region of altered solubility in the first resist. Although the diffusion of the first solubility modifier may occur at different times in such a method and may diffuse into different components, the diffusion of the solubility modifier may be performed as described above in method 100. After the first solubility modifier is diffused into the first resist, a first polymer fill may be deposited on the substrate. A second relief pattern may then be laminated onto the first relief pattern as described above. A second solubility modifier may then be coated onto the second relief pattern and then diffused into the second relief pattern. Diffusion of the second solubility modifier can provide solubility-altered regions or a second resist. A second polymer fill is then deposited over the second relief pattern. Finally, the substrate can be developed and etched as described with respect to method 100, but in this case the solubility-altered regions of the first resist and second resist are soluble in a particular developer.

[0112] The methods and systems of one or more embodiments rely on both chemical process and diffusion characteristics to provide a unique ability to apply control functions to input chemical reactions themselves and a way to measure such reactions.

[0113] Embodiments of the present disclosure may provide at least one of the following advantages: The method in one or more embodiments provides the ability to etch high-density contact array patterns into a substrate without the need for traditional, expensive lithography steps. As such, the method in the present disclosure provides lower-cost, high-density contact arrays, such as memory devices. Lithography control is maintained, thereby enabling the formation of patterned regions around the periphery of the contact array. Therefore, the methods disclosed herein enable track-based or in-resist anti-spacer techniques for contact arrays, thereby eliminating the need for atomic layer deposition (ALD) and etching techniques.

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

Claims

1. 1. A method of microfabrication comprising: providing a substrate having a target layer formed thereon; forming a first relief pattern on a substrate, the first relief pattern comprising a first resist; coating the first relief pattern with a first solubility modifier; depositing a first polymer fill onto the first relief pattern; diffusing the first solubility modifier a predetermined distance into the first polymer fill to provide an altered solubility region of the first polymer fill, the altered solubility region of the first polymer fill adjacent the first relief pattern, the altered solubility region of the first polymer fill being soluble in a first developer; forming a second relief pattern on the first relief pattern, the second relief pattern comprising a second resist; and coating the second relief pattern with a second solubility modifier; depositing a second polymer fill onto the second relief pattern; diffusing the second solubility modification a predetermined distance into the second polymer fill to provide a solubility-altered region of the second polymer fill, the solubility-altered region of the second polymer fill adjacent the second relief pattern, the solubility-altered region of the second polymer fill being soluble in a second developer; developing the first polymer fill and the second polymer fill to dissolve the altered solubility areas of the first polymer fill and the altered solubility areas of the second polymer fill and to provide gaps between the first relief pattern, the first polymer fill, the second relief pattern, and the second polymer fill, exposing portions of the target layer; and etching the target layer using the first relief pattern, the first polymer fill, the second relief pattern, and the second polymer fill as a combined etch mask.

2. 2. The method of claim 1, wherein the first relief pattern comprises features separated by gaps between the features, the features comprising the first resist.

3. The method of claim 2 , wherein the first polymer fill fills the gaps in the first relief pattern.

4. 3. The method of claim 1, wherein the second relief pattern comprises features separated by gaps between the features, the features comprising the second resist.

5. The method of claim 4 , wherein the second polymer fill fills the gaps in the second relief pattern.

6. The method of claim 1 or 2, wherein etching the substrate comprises performing an anisotropic etch.

7. providing the first relief pattern on the target layer; forming a first pattern of lines on the target layer; depositing the first layer of resist over the first pattern of lines; 3. The method of claim 1, comprising exposing the first resist to a pattern of actinic radiation; and developing the first resist to form the first relief pattern on the first pattern of lines.

8. The method of claim 1 or 2, wherein the first solubility modifier comprises an acid generator.

9. The method of claim 8 , wherein the acid generator is fluorine-free.

10. 9. The method of claim 8, wherein the acid generator 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.

11. The method of claim 1 or 2, wherein the first solubility modifier comprises an acid.

12. The method of claim 11 , wherein the acid is fluorine-free.

13. 12. The method of claim 11, 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.

14. 3. The method of claim 1 or 2, wherein the first solubility modifier comprises a matrix polymer comprising one or more monomers selected from monomers having an ethylenically unsaturated polymerizable double bond, including (meth)acrylate monomers, (meth)acrylic acid, styrene, hydroxystyrene, vinyl naphthalene, acenaphthylene, vinyl alcohol, vinyl chloride, vinyl pyrrolidone, vinyl pyridine, vinyl amine, vinyl acetal, maleic anhydride, maleimide, norbornene, or combinations thereof.

15. The method of claim 1 or 2, wherein the second solubility modifier comprises an acid generator.

16. The method of claim 15 , wherein the acid generator is fluorine-free.

17. 16. The method of claim 15, wherein the acid generator 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.

18. The method of claim 1 or 2, wherein the second solubility modifier comprises an acid.

19. 20. The method of claim 18, wherein the acid is fluorine-free.

20. 19. The method of claim 18, 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.

21. 3. The method of claim 1 or 2, wherein the second solubility modifier comprises a matrix polymer comprising one or more monomers selected from monomers having an ethylenically unsaturated polymerizable double bond, including (meth)acrylate monomers, (meth)acrylic acid, styrene, hydroxystyrene, vinyl naphthalene and acenaphthylene, vinyl alcohol, vinyl chloride, vinyl pyrrolidone, vinyl pyridine, vinyl amine, vinyl acetal, maleic anhydride, maleimide, norbornene, and combinations thereof.

22. 3. The method of claim 1, wherein the first resist is a positive tone developing resist and the first polymer fill comprises a polymer that is soluble in a polar solvent.

23. 3. The method of claim 1, wherein the first resist is a negative tone development resist and the first polymer fill comprises a polymer that is soluble in a non-polar organic solvent.

24. The method of claim 1 or 2, wherein the first solubility modifier comprises a solvent.

25. 25. The method of claim 24, wherein the solvent is selected from the group consisting of methyl isobutyl carbinol (MIBC), decane, isobutyl isobutyrate, isoamyl ether, and combinations thereof.

26. 25. The method of claim 24, wherein the first resist is insoluble in the solvent.

27. The method of claim 1 or 2, wherein the first resist comprises a polymer made from monomers selected from the group consisting of styrene, p-hydroxystyrene, methacrylate, norbornene, and combinations thereof.

28. The method of claim 1 or 2, wherein the first polymer fill comprises a polymer made from a monomer selected from the group consisting of styrene, p-hydroxystyrene, methacrylate, norbornene, and combinations thereof.

29. 23. The method of claim 22, wherein the specific developer is tetramethylammonium hydroxide.

30. 24. The method of claim 23, wherein the specific developer is a non-polar organic solvent selected from the group consisting of n-butyl acetate (NBA), 2-heptanone, and combinations thereof.

31. 3. The method of claim 1, wherein the second resist is a positive tone developing resist and the second polymer fill comprises a polymer that is soluble in a polar solvent.

32. 3. The method of claim 1, wherein the second resist is a negative tone development resist and the second polymer fill comprises a polymer that is soluble in a non-polar organic solvent.

33. The method of claim 1 or 2, wherein the second solubility modifier comprises a solvent.

34. 34. The method of claim 33, wherein the solvent is selected from the group consisting of methyl isobutyl carbinol (MIBC), decane, isobutyl isobutyrate, isoamyl ether, and combinations thereof.

35. The method of claim 1 or 2, wherein the second resist comprises a polymer made from monomers selected from the group consisting of styrene, p-hydroxystyrene, methacrylate, norbornene, and combinations thereof.

36. The method of claim 1 or 2, wherein the second polymer fill comprises a polymer made from a monomer selected from the group consisting of styrene, p-hydroxystyrene, methacrylate, norbornene, and combinations thereof.

37. 32. The method of claim 31, wherein the specific developer is tetramethylammonium hydroxide.

38. 33. The method of claim 32, wherein the specific developer is a non-polar organic solvent selected from the group consisting of n-butyl acetate (NBA), 2-heptanone, and combinations thereof.

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