Multi-line etching substrate generation

Abstract

A micro-fabrication method includes providing a first relief pattern on a target layer, the first relief pattern including a first resist having a first etch selectivity; coating the first relief pattern with a solubility modifier; depositing a second resist on the first relief pattern, the second resist having a second etch selectivity different from the first etch selectivity; diffusing the solubility modifier into the second resist to provide solubility-modified regions of the second resist; developing the second resist such that the solubility-modified regions are dissolved to provide gaps between the first relief pattern and the second resist where portions of the target layer are exposed; and filling the gaps between the first relief pattern and the second resist with a fill material.

Description

[Background technology]

[0001] Microfabrication of semiconductor devices involves various steps such as film deposition, patterning and pattern transfer. Materials and films are deposited on substrates by spin-coating, evaporation and other deposition processes. Patterning is typically performed by exposing a photosensitive film, known as photoresist, to a pattern of actinic radiation and then developing the photoresist to form a relief pattern. The relief pattern then acts as an etch mask that covers the portions of the substrate that are not to be etched when the substrate is subjected to one or more etching processes.

[0002] Multi-patterning is a term that describes the use of multiple lithography steps to create the final pattern. Multi-patterning in its various forms enables the fabrication of advanced semiconductor devices. Patterning typically involves two basic steps. The first step involves using lithography to create the pattern using mask-based exposure followed by development of soluble areas. 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 patterning the device.

[0003] To create advanced devices, several patterning steps may be used. For example, some areas may be patterned with some form of multi-patterning and then cut between certain regions using a cut mask. Some active areas may be "bridged" with patterns connecting various regions. Advanced pattern structures may be created using 5-6 exposures, which ideally do not interact. For example, the bridges should not destroy the separation of different regions. To achieve such advanced patterning, elaborate multi-step patterning processes have been developed. Typical multi-patterning schemes are complex, expensive, and difficult to switch between at each step of the patterning process. Simplification of these steps would be beneficial by providing better throughput, time, and ultimately shrink capabilities. Summary of the Invention [Means for solving the problem]

[0004] 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.

[0005] In one aspect, embodiments disclosed herein relate to a micro-fabrication method that includes providing a first relief pattern on a target layer, the first relief pattern comprising a first resist having a first etch selectivity; coating the first relief pattern with a solubility modifier; depositing a second resist on the first relief pattern such that the second resist is in contact with the first relief pattern, the second resist having a second etch selectivity different from the first etch selectivity; diffusing the solubility modifier a predetermined distance into the second resist to provide a solubility-modified region of the second resist, the solubility-modified region of the second resist adjacent the first relief pattern; developing the second resist such that the solubility-modified region is dissolved to provide a gap between the first relief pattern and the second resist where a portion of the target layer is exposed; and filling the gap between the first relief pattern and the second resist with a fill material.

[0006] In another aspect, embodiments disclosed herein relate to a micro-fabrication method that includes providing a first relief pattern on a target layer, the first relief pattern comprising a first resist having a first etch selectivity; coating the first relief pattern with a solubility modifier and diffusing the solubility modifier a predetermined distance into the first resist to provide a solubility-modified region of the first resist; depositing a second resist on the first relief pattern such that the second resist is in contact with the first relief pattern, the second resist having a second etch selectivity different from the first etch selectivity; developing the first resist such that the solubility-modified region is dissolved to provide a gap between the first relief pattern and the second resist where a portion of the target layer is exposed; and filling the gap between the first relief pattern and the second resist with a fill material.

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

[0008] [Figure 1] FIG. 2 is a schematic diagram of a multi-line layer in accordance with one or more embodiments of the present disclosure.

[0009] [Diagram 2] FIG. 2 is a schematic diagram of a patterned multi-line layer in accordance with one or more embodiments of the present disclosure.

[0010] [Diagram 3] FIG. 1 is a block flow diagram of a method according to one or more embodiments of the present disclosure.

[0011] [Figure 4A] 1A-1D are schematic diagrams of a coated substrate at various points in a method according to one or more embodiments of the present disclosure. [Figure 4B] 1A-1D are schematic diagrams of a coated substrate at various points in a method according to one or more embodiments of the present disclosure. [Figure 4C] 1A-1D are schematic diagrams of a coated substrate at various points in a method according to one or more embodiments of the present disclosure. [Figure 4D] 1A-1D are schematic diagrams of a coated substrate at various points in a method according to one or more embodiments of the present disclosure. [Figure 4E] 1A-1D are schematic diagrams of a coated substrate at various points in a method according to one or more embodiments of the present disclosure. [Figure 4F] 1A-1D are schematic diagrams of a coated substrate at various points in a method according to one or more embodiments of the present disclosure.

[0012] [Diagram 5] FIG. 1 is a block flow diagram of a method according to one or more embodiments of the present disclosure.

[0013] [Figure 6A] 1A-1D are schematic diagrams of a coated substrate at various points in a method according to one or more embodiments of the present disclosure. [Figure 6B] 1A-1D are schematic diagrams of a coated substrate at various points in a method according to one or more embodiments of the present disclosure. [Figure 6C] 1A-1D are schematic diagrams of a coated substrate at various points in a method according to one or more embodiments of the present disclosure. [Figure 6D] 1A-1D are schematic diagrams of a coated substrate at various points in a method according to one or more embodiments of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] In multi-patterning of a substrate, the initial patterning should generate a pattern that can be accurately placed in the target layer. The initial pattern can be formed using a variety of different layers. The various different layers should be sufficiently different so that each layer can be selectively formed in the final substrate or structure. The selective formation of each layer can be achieved using techniques such as multi-line layers or multi-color layers. A multi-line layer is a plane or layer of two or three different alternating materials. Each of these materials can be selected so that it can be etched without etching the other materials. Such techniques to achieve selective etching are usually not complete, but are sufficient. For example, one material may be completely etched while the other materials are only partially etched, thereby still providing masking of the underlying layers.

[0015] A preferred multi-line layer is the "ABC" layout. This layer has three different materials (A, B, and C) that are alternated, typically in the order ABCBA, with material B appearing in every other position while materials A and C have three lines in between before repeating. Figure 1 shows an exemplary multi-line layer with an ABC pattern.

[0016] In such a multi-line layer, material A or material C can be etched independently, which allows for the creation of more complex patterns for advanced devices. Furthermore, the multi-line layer can be masked to create openings. Such openings can be wider than required, but the etching using an etch mask can be further limited because the dissimilar materials in the multi-line layer have different etch resistances. For example, by using a relatively large pattern on C that is wider than desired, the directional etch of C will not create openings where A and B will appear. In this way, a buffer zone is essentially provided. Having an ABC pattern dramatically simplifies the lithography and etching requirements for making complex patterns.

[0017] FIG. 2 shows an example where precise breaks (not necessarily required for material C) and precise crossovers in the final pattern are formed. Without the C region, the required perfection exceeds the resolution capabilities of conventional tools. Conventional multi-patterning therefore relies on protection, composite patterns and local patterns. This may be necessary for some materials, as gas-phase etching has low selectivity between dissimilar materials. In some designs, only two patterns are required, such as A / C and B. This means that A and C can be the same material or have essentially similar etching properties. The A / C scheme allows for some degree of cut (break A or C) and bridge (break B) patterns.

[0018] Although multi-line layers are useful in patterning, one of the drawbacks is the processing time and cost to create the ABC pattern. Traditionally, this pattern is created using inorganic or relatively hard materials. For example, a resist mask may be used to etch and create the lines or mandrels (material A). The resist may then be stripped from the substrate, after which a conformal deposition may be performed, typically using chemical vapor deposition (CVD) or atomic layer deposition (ALD). A spacer etch process may then be performed. The spacer etch process may directionally etch the conformal material from the horizontal surfaces, leaving behind the sidewall deposition (material B). A filler material may then be deposited to fill the openings between the sidewall spacers (material C). The overburden of the filler material may be removed by controlled etching or chemical mechanical polishing. Thus, the creation of such a multi-line layer includes scanners / steppers, coater developers (track tools), deposition chambers, etch chambers, and CMP tools. Thus, the cost and time of such patterning is relatively high.

[0019] The present disclosure generally relates to a method for multi-patterning a semiconductor substrate. In this specification, the terms "semiconductor substrate" and "substrate" are used interchangeably and may be any semiconductor material, including, but not limited to, a semiconductor wafer, a semiconductor material layer, and combinations thereof. In one or more embodiments, the method includes forming a multi-line layer from a resist material rather than a hard mask material used in conventional methods. Thus, the method of one or more embodiments may be applied to advanced lithography techniques, primarily using track tools. The resist-based multi-line layer disclosed herein may enable sub-resolution patterns to be obtained with reduced time and cost.

[0020] In one or more embodiments, the method includes converting a typical polymer pattern into a compatible ABC or AB etch pattern with etch-independent materials. The method includes using a negative spacer flow (anti-spacer flow), which may enable effective cut and bridge patterning. In certain embodiments, an anti-spacer flow having a pattern including two polymers with a space between them is formed and used to provide an ABC patterned multi-line layer. A method 300 according to such an embodiment is shown in and discussed with reference to FIG. 3.

[0021] In a negative spacer or anti-spacer flow, an initial pattern of resist is provided on a substrate, as shown in block 302 of FIG. 3. The initial pattern of resist may also be referred to herein as an initial relief pattern. In one or more embodiments, one or more intermediate layers may be disposed between the initial relief pattern and the underlying target layer. Suitable intermediate layers include hard mask layers and bottom antireflective coating layers (BARC), among others. The target layer may be any suitable layer, such as those used in the art to receive the pattern. The initial relief pattern may include a first resist having a first etch selectivity. Then, in block 304, a chemical exposure material or diffusing agent is deposited on the patterned resist. As used herein, the terms "diffusing agent" and "solubility modifying agent" may be used interchangeably to describe an agent that diffuses into the first resist or second resist and modifies their solubility. For diffusing agent deposition, a diffusing agent (e.g., an acid) may be coated on the first relief pattern. Next, in block 306, a second resist or solubility-modifiable polymer is deposited on the substrate to fill the openings defined by the first resist. The second resist may have a second etch selectivity that is different from the first etch selectivity of the first resist. That is, while there are some etchants (etch chemistry combinations) that etch both materials, there are other etchants that etch the first resist or the second resist without etching the other resist. The more etch-resistant resist may be selected based on the patterning goal or design and thus may be customized. In block 308, diffusion into the second resist or polymer is initiated. The diffusion may be heat activated. The solubility modifier may include a photosensitive compound that generates the solubility modifier upon exposure to actinic radiation. The amount of diffusion into the second resist may be precisely controlled on the nanometer scale by the time and temperature of the process. Such control may enable feature dimensions much smaller than conventional lithography resolution.For example, a 193 nm lithography tool can comfortably print features with widths of 193 nm or more. Using some optical tricks, lines can be printed down to about 80 nm. However, acid diffusion can be controlled to within a few nanometers.

[0022] After acid diffusion, the areas between the first and second resists become soluble and can be removed by developing chemicals. In block 310, the soluble areas (also referred to as the solubility-modified areas of the second resist) can be developed using a specific developing chemical to create spaces (negative spacers or anti-spacers) around the first resist. Then, by relying on the different etch selectivities or etch resistances of the first and second resists, the substrate can be selectively etched in a complex pattern in block 310 of method 300. The result of this type of patterning is a resist or two different resists with a narrow gap separating each resist. To create a highly selective pattern, the second resist can have a significantly different composition than the first resist. Finally, in block 312, the gaps are filled with a fill material to provide an ABC patterned multi-line layer.

[0023] Schematic diagrams of the coated substrate at various times during the above-mentioned method are shown in Figures 4A-4E. 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 second resist layer. The coated substrate may first be coated with a target layer. Figure 4A shows the target layer including a first relief pattern. Figure 4B shows the target layer including the first relief pattern coated with a solubility modifier. In Figure 4C, a second resist is laminated onto the substrate and the first relief pattern. Figure 4D shows the coated substrate after the solubility modifier has diffused into the second resist. Finally, Figure 4E shows the coated substrate after the second resist has been developed to form trenches between the second resist and the first relief pattern. Finally, Figure 4F shows the target layer in which the trenches between the second resist and the first relief pattern have been filled with a fill material to provide an ABC patterned multiline layer. The method of Figure 3 and the coated substrates shown in Figures 4A-4F are discussed in more detail below.

[0024] In block 302 of the method 300, a first relief pattern is provided. FIG. 4A shows an example of a first relief pattern 404 on a target layer 402. The target layer can be a substrate or any other suitable layer capable of receiving a pattern. As shown in FIG. 4A, the first relief pattern can include features separated by gaps. Portions of the target layer can be exposed due to the presence of the gaps in the first relief pattern. The features of the first relief pattern can be made from a first resist 403. The first resist can be a photoresist. Generally, a photoresist is a chemically amplified photosensitive composition that includes a polymer, a photoacid generator, and a solvent. For example, the polymer can be a polymer made from monomers including aromatic vinyl monomers such as styrene and p-hydroxystyrene, acrylates, methacrylates, norbornenes, and combinations thereof. Monomers that include 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 change 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 reason. Acid labile groups include, for example, tertiary alkyl ester groups, secondary or tertiary aryl ester groups, secondary or tertiary ester groups with 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 dissociable groups", "acid dissociable protecting groups", "acid labile protecting groups", "acid leaving groups" and "acid sensitive groups".

[0025] The acid labile groups which upon decomposition form carboxylic acids in the polymer are preferably tertiary ester groups of the formula -C(O)OC(R1)3 or acetal groups of the formula -C(O)OC(R2)2OR3, where each R1 is independently a linear C1-20 alkyl, a branched C3-20 alkyl, a monocyclic or polycyclic C3-20 cycloalkyl, a linear C2-20 alkenyl, a branched C3-20 alkenyl, a monocyclic or polycyclic C3-20 cycloalkenyl, a monocyclic or polycyclic C6-20 aryl, or a monocyclic or polycyclic C2-20 heteroaryl, and are preferably or linear C1-6 alkyl, branched C3-6 alkyl, or monocyclic or polycyclic C3-10 cycloalkyl, each of which is substituted or unsubstituted; each R1 optionally includes one or more groups selected from -O-, -C(O)-, -C(O)-O- or -S- as part of its structure; any two R1 groups together optionally form a ring; R2 is independently hydrogen, fluorine, linear C1-20 alkyl, branched C3-20 alkyl, monocyclic or polycyclic C3-20 cycloalkyl, linear C2-20 alkenyl, branched C3-20 a R2 is optionally a straight chain C1-6 alkyl, a branched C3-6 alkyl, or a monocyclic or polycyclic C3-10 cycloalkyl, each of which is substituted or unsubstituted; each R2 optionally includes as part of its structure one or more groups selected from -O-, -C(O)-, -C(O)-O- or -S-; the R2 groups together optionally form a ring; R3 is preferably a straight chain C1-6 alkyl, a branched C3-6 alkyl, or a monocyclic or polycyclic C3-10 cycloalkyl, each of which is substituted or unsubstituted; R3 is optionally -O-, -C(O) ...It contains one or more groups selected from -C(O)-O- or -S-, and one R2 together with R3 optionally forms a ring. Such monomers are typically aromatic vinyl, (meth)acrylate or norbornyl monomers. The total content of polymerized units containing acid-decomposable groups forming 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.

[0026] The polymer may further comprise a monomer comprising an acid labile group which, upon polymerization, decomposes to form an alcohol or fluoroalcohol group on the polymer. Suitable such groups include, for example, an acetal group of formula -COC(R2)2OR3-, or a carbonate group of 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 comprising an acid decomposable group which, upon decomposition, forms an alcohol or fluoroalcohol group on the polymer is typically 10-90 mol %, more typically 30-70 mol %, based on the total polymerized units of the polymer.

[0027] In another embodiment, the polymer may be a polymer that includes silicon-containing units that can be chemically bonded to the polymeric material. In a preferred embodiment, the silicon-containing units include silicon-oxygen bonds. Resists that include such polymers may be referred to herein as "silicon-based resists." Examples of silicon-containing resists are disclosed in U.S. Pat. Nos. 5,985,524, 6,444,408, 6,670,093, and 6,596,830, as well as Schaedeli et al., "Bilayer Resist Approach for 193 nm Lithography," Proc. SPIE, Vol. 2724, pp. 344-354, 1996, and Kessel et al., "Novel Silicon-Containing Resists for EUV and 193 nm Lithography," Proc. SPIE, Vol. 3678, pp. 214-220, 1999.

[0028] The first resist of one or more embodiments is an organometallic or metal-based resist based on metal oxide chemistry, including metal oxo / hydroxo compositions that utilize radiation-sensitive ligands to enable patterning by actinic radiation. One class of radiation-based resists uses peroxo ligands as radiation-sensitive stabilizing ligands. Peroxo-based metal oxo-hydroxo compounds are described, for example, in U.S. Pat. No. 9,176,377 to Stowers et al., entitled "Patterned Inorganic Layers, Radiation Based Patterning Compositions and Corresponding Methods," which is incorporated herein by reference. Related resist compounds are discussed in U.S. Pat. App. Pub. No. 2013 / 0224652 to Bass et al., entitled "Metal Peroxo Compounds With Organic Co-ligands for Electron Beam, Deep UV and Extreme UV Resist Applications," which is incorporated herein by reference. Effective types of resists have been developed using alkyl ligands as described in U.S. Pat. No. 9,310,684 to Meyers et al., entitled "Organometallic Solution Based High Resolution Patterning Compositions," U.S. Patent Application Publication No. 2016 / 0116839 to Meyers et al., entitled "Organometallic Solution Based High Resolution Patterning Compositions and Corresponding Methods," and U.S. Patent Application Serial No. 15 / 291,738, entitled "Organotin Oxide Hydroxide Patterning Compositions, Precursors, and Patterning," all of which are incorporated herein by reference.Tin compositions are exemplified in these documents, and although the data presented herein focuses on tin-based resists, the edge bead removal solution described herein is expected to be effective for other metal-based resists described below.

[0029] Regarding tin-based resists of particular interest, these resists are based on the chemical reaction of an organometallic composition represented by the formula RzSnO(2-(z / 2)-(x / 2))(OH)x [where 0 < z ≤ 2 and 0 < (z + x) ≤ 4, and R is a hydrocarbyl group having 1 to 31 carbon atoms]. However, at least a part of the oxo / hydroxo ligands is formed after deposition based on in-situ hydrolysis based on a composition represented by the formula RnSnX4-n [where n = 1 or 2, and X is a ligand having a hydrolyzable M-X bond]. In general, suitable hydrolyzable ligands (X in RSnX3) can include alkynides RC≡C, alkoxides RO-, azides N3-, carboxylates RCOO-, halides, and dialkylamides. Therefore, in some embodiments, all or part of the oxo-hydroxo composition can be replaced with an Sn-X composition or a mixture thereof. The R-Sn bond is generally radiation-sensitive and forms the basis for the aspect where the resist can be radiation-treated. However, a part of the RzSnO(2-(z / 2)-(x / 2))(OH)x composition can be replaced with MO((m / 2)-l / 2)(OH)x (where 0 < z ≤ 2, 0 < (z + w) ≤ 4, m is the formal valence of Mm+, 0 ≤ l ≤ m, y / z = (0.05 to 0.6), M = M' or Sn, M' is a non-tin metal in Groups 2 to 16 of the periodic table, and R is a hydrocarbyl group having 1 to 31 carbon atoms). Therefore, the resist treated during edge bead rinsing can include a selected blend of RzSnO(2-(z / 2)-(x / 2))(OH)x, R'nSnX4-n, and / or MO((m / 2)-l / 2)(OH)x, but generally a significant proportion of this composition contains alkyl-tin bonds. Other resist compositions include, for example, compositions having a metal carboxylate bond such as dibutyltin diacetate (ligands such as acetate, propanoate, butanoate, benzoate, etc.).

[0030] While the metal oxo / hydroxo or carboxylate-based resists mentioned above are particularly desirable, in some embodiments, a number of other high performance resists may be suitable, particularly other metal-based resists that have high etch selectivity to the template, fill material, and buffer hardmasks. These can include resists such as metal oxide nanoparticle resists (e.g., Jiang, Jing; Chakrabarty, Souvik; Yu, Mufei; et al., "Metal Oxide Nanoparticle Resists for EUV Patterning", Journal Of Photopolymer Science And Technology 27(5), 663-666 2014, incorporated herein by reference), or other metal-containing resists (A Platinum-Fullerene Complex for Patterning Metal Containing Nanostructures, DX Yang, A. Frommhold, DS He, ZY Li, RE Palmer, MA Lebedeva, TW Chamberlain, ANKhlobystov, APG Robinson, Proc SPIE Advanced Lithography, 2014, incorporated herein by reference). Other metal-based resists are described in U.S. Patent Application Publication No. 2009 / 0155546 to Yamashita et al., entitled "Film-Forming Composition, Method for Pattern Formation, and Three-Dimensional Mold," and U.S. Patent No. 6,566,276 to Maloney et al., entitled "Method of Making Electronic Materials," both of which are incorporated herein by reference.

[0031] In an embodiment in which the first resist is a photoresist, the first resist comprises a photoacid generator. The photoacid generator is a compound capable of generating an acid when exposed to actinic rays or radiation. The photoacid generator can be selected from known compounds capable of generating an acid when exposed to actinic rays or radiation, such as photoinitiators for cationic photopolymerization, photoinitiators for radical photopolymerization, photobleaching agents for dyes, photochromic agents, microresists, etc., and mixtures thereof can be used. Examples of photoacid generators include diazonium salts, phosphonium salts, sulfonium salts, iodonium salts, imidosulfonates, oximesulfonates, diazodisulfones, disulfones, and o-nitrobenzylsulfonates.

[0032] Suitable photoacids include 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 are used as photoacid generators. They are also known to function as photocatalyst generators, for example, nitrobenzyl derivatives, such as 2-nitrobenzyl-p-toluenesulfonate, 2,6-dinitrobenzyl-p-toluenesulfonate and 2,4-dinitrobenzyl-p-toluenesulfonate; sulfonic acid 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, 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-polymerizing photoacid generators are further described in U.S. Patent No. 8,431,325 to Hashimoto et al. (column 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. Patents 4,189,323 and 8,431,325. PAGs that are onium salts typically contain anions with sulfonate or non-sulfonate groups, such as sulfonamidate, sulfonimidate, methide or borate groups.

[0033] The resist composition may optionally include 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, the first PAG includes a sulfonate group in the anion, and the second PAG includes an anion that does not include a sulfonate group, such as a sulfonamidate group, a sulfonimidate group, a methide group, or a borate group, as described above.

[0034] In one or more embodiments, a first resist may have a first etch selectivity, such that it may be etched somewhat more easily than another resist. Etching of resists is typically performed by anisotropic dry etching, such as reactive ion etching, where the etching chemistry depends on the particular materials that make up the layer. The etching process rate or etch rate of a material depends on the composition of the material and etchant, as well as various process conditions. For example, an organic composition may be etched quickly with oxygen plasma, but is resistant to etching using a fluorine-containing etchant. Silicon-containing compositions may increase their etch resistance to oxygen plasma as the silicon content increases. High silicon polymers are generally more resistant to oxygen plasma reactive ion etching, but can be etched using a fluorine-containing etchant. Metals similarly impart different etch selectivities to metal-containing resists.

[0035] In some embodiments, the first resist comprises an etch resistance enhancer. The inclusion of a suitable etch resistance enhancer can increase the resistance of the first resist to etching, as described above.

[0036] The first relief pattern may be formed by laminating a first resist onto the target layer and developing the first resist. The first resist may be developed according to procedures known in the art, such as exposure to actinic radiation followed by rinsing with a first resist developer. A mask may be used to block portions of the resist from actinic radiation to impart a shape or relief pattern to the developed resist. After actinic radiation is applied, the unexposed portions of the resist may have a different solubility than the exposed portions of the resist. Rinsing with a first resist developer then dissolves either the unexposed or exposed portions. If the unexposed portions of the resist remain after rinsing with a developer, the relief pattern provided is a positive tone developed resist. In contrast, if the exposed portions of the resist remain after rinsing with a developer, the relief pattern provided is a negative tone developed resist.

[0037] In one or more embodiments, the first resist is a negative resist. In such embodiments, the first relief pattern may include a polymer made from the monomers described above, where 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 a suitable developer to form the relief pattern. The negative resist may also be an organometallic or metallic resist.

[0038] In other embodiments, the first resist is a negative tone developed (NTD) resist. NTD resists may include polymers made from the monomers described above, where any monomer containing reactive functional groups is protected. Thus, NTD first resists may be organic soluble, but instead of developing the exposed areas with a first resist developer that is basic, the first relief pattern may be provided by rinsing the first resist with a first resist developer that includes an organic solvent. Suitable organic solvents that may be used as first resist developers include n-butyl acetate (NBA) and 2-heptanone. The tone of the resist (i.e., negative vs. NTD) may affect the subsequent chemical reactions applied to the first relief pattern.

[0039] As discussed 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 Å to about 3000 Å. The gaps separating the features can leave a portion of the substrate exposed.

[0040] In block 304 of method 300, the first relief pattern is coated with a solubility modifier. The coated substrate from block 304 is shown in FIG. 4B. The solubility modifier 405 is shown as a thin coating on the first relief pattern 404. The thickness of the solubility modifier coating is not particularly limited and may vary based on the desired line cut width. The solubility modifier may be a material that is absorbed into the first resist upon baking and may be referred to as an "absorbing material" in some examples herein. The process of absorbing or diffusing the solubility modifier into the first resist is described in detail below.

[0041] The composition of the solubility modifier may depend on the tone of the first resist and the second resist. In general, the solubility modifier may be any chemical that is activated by light or heat. For example, if the second resist comprises a chemically amplified resist, the solubility modifier may comprise an acid or a thermal acid generator (TAG). The acid, or in the case of a TAG, the generated acid, should be sufficient to break down the bonds of the acid-labile groups of the polymer in the surface region of the first resist pattern by heat, increasing 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% by weight based on the total solids content of the trimming composition.

[0042] Preferred acids include organic acids, including non-aromatic or aromatic acids, each of which can optionally have fluorine substitution. Suitable organic acids include, for example, carboxylic acids such as alkanoic acids, including formic acid, acetic acid, propionic acid, butyric acid, dichloroacetic acid, trichloroacetic acid, perfluoroacetic acid, perfluorooctanoic acid, oxalic acid, 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.

[0043] Exemplary fluorine-free aromatic acids include aromatic acids of the general formula (I):

[0044] [ka]

[0045] [In the 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, 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]

[0046] An exemplary aromatic acid may be of the following general formula (II):

[0047] [ka]

[0048] [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 each independently represent an integer of 0 to 4, c+d is 4 or less; and e and f each independently represent an integer of 0 to 3, and e+f is 3 or less]

[0049] Additional aromatic acids that may be included in the solubility modifier include those of the general formula (III) or (IV) below.

[0050] [ka]

[0051] [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 each independently represent an integer of 0 to 4, and g+h is 4 or less; i and j each independently represent an integer of 0 to 2, and i+j is 2 or less; k and 1 each independently represent an integer of 0 to 3, and k+l is 3 or less]

[0052] [ka]

[0053] [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 each independently represent an integer of 0 to 4, and g+h is 4 or less; i and j each independently represent an integer of 0 to 1, and i+j is 1 or less; and k and l each independently represent an integer of 0 to 4, and k+l is 4 or less]

[0054] A suitable aromatic acid may alternatively be of the following general formula (V):

[0055] [ka]

[0056] [In the 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, sulfonamide, ether, thioether, a 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, 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]

[0057] Further, exemplary aromatic acids can have the following general formula (VI):

[0058] [ka]

[0059] [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, a 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; q and r independently represent integers of 0 to 3, and q+r is 3 or less]

[0060] 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:

[0061] [ka]

change

[0062]

change

change

change

[0063] Suitable TAGs include those capable of generating non-polymerizable acids as described above. 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-benzoyl-benzenesulfonic acid, and their salts, and 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.

[0064] Preferably, the TAG is ionic in the reaction scheme for generating a sulfonic acid as shown below.

[0065] [ka]

[0066] 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):

[0067] (BH) + (I)

[0068] 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, for example, pyridine or substituted pyridines (e.g., 3-fluoropyridine), nitrogen-containing heteroaromatic bases such as pyrimidines and pyrazines, nitrogen-containing heterocyclic groups such as oxazole, oxazoline or thiazoline. The aforementioned nitrogen-containing bases B can be optionally substituted with one or more groups selected from alkyl, aryl, halogen atoms (preferably fluorine), cyano, nitro and alkoxy. Of these, base B is preferably a heteroaromatic base.

[0069] 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, the term "pKa" is used according to its 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. + C. is the negative logarithm (base 10) of the dissociation constant of . In certain embodiments, base B has a boiling point of less than about 170.degree. C., less than about 160.degree. C., 150.degree. C., 140.degree. C., 130.degree. C., 120.degree. C., 110.degree. C., 100.degree. C., or less than 90.degree.

[0070] Suitable exemplary nitrogen-containing cations (BH) + As for NH4 + , CF2HNH2 + , CF3CH2NH3 +, (CH3)3NH + , (C2H5)3NH + , (CH3)2(C2H5)NH + and the following:

[0071] [ka]

[0072] wherein Y is alkyl, preferably methyl or ethyl.

[0073] 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-butylphenyl tetramethylenesulfonium perfluoro-1-butanesulfonate, 4-t-butylphenyl tetramethylenesulfonium 2-trifluoromethylbenzenesulfonate, and 4-t-butylphenyl tetramethylenesulfonium 4,4,5,5,6,6-hexafluorodihydro-4H-1,3,2-dithiazine 1,1,3,3-tetraoxide; or a combination thereof. Acid from the solubility modifier diffuses from the first resist into the second resist, deprotecting the second resist polymer in the layer adjacent to the first resist, making it soluble in a basic developer such as tetramethylammonium hydroxide (TMAH).

[0074] Alternatively, the second resist may be treated similarly to the NTD resist if the solubility modifier comprises a base or base generator. In this case, the second resist is formulated to include an acid or acid generator. The base from the solubility modifier diffuses from the first resist into the second resist and quenches the acid in areas adjacent to the first resist, allowing those areas to be developed with an organic solvent such as NBA. 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. The amines may be primary amines, secondary amines, 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 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 hydroxylamine. Examples of hydroxyamines include hydroxyamines having one or more hydroxyalkyl groups (e.g., hydroxymethyl, hydroxyethyl, and hydroxybutyl) 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.

[0075] A suitable base generator may be a thermal base generator. The thermal base generator forms a base when heated 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.

[0076] In one or more embodiments, the solubility modifier comprises a solvent. As mentioned above, in some embodiments, the solubility modifier is absorbed into the first relief pattern. Thus, the solvent can be any suitable solvent that can facilitate absorption into the first relief pattern, as long as it does not dissolve the first photoresist. The solvent is typically selected from water, organic solvents, and mixtures thereof. In some embodiments, the solvent can comprise an organic-based solvent system that includes one or more organic solvents. The term "organic-based" means that the solvent system includes more than 50% organic solvent by weight based on the total solvent of the solubility modifier composition, and more typically includes more than 90%, more than 95%, more than 99%, or 100% organic solvent by weight based on the total solvent of the solubility modifier composition. The solvent component is typically present in an amount of 90-99% by weight based on the solubility modifier composition.

[0077] 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; aliphatic hydrocarbons such as hexane, 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 -alcohols such as linear, branched or cyclic C4-C9 monohydric alcohols such as heptanol, 1-octanol, 2-hexanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol, 3-octanol and 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-hexa 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 comprising one or more of these solvents.

[0078] The solvent included in the absorbing material may 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 may include a polar solvent, such as methyl isobutyl carbinol (MIBC). The solubility modifier may also include aliphatic hydrocarbons, esters and ethers, such as decane, isobutyl isobutyrate, isoamyl ether and combinations thereof, as co-solvents. In certain embodiments, the solvent includes MIBC and a co-solvent. In such embodiments, MIBC may be included in the solvent in an amount ranging from 60 to 99% based on the total solvent volume. Thus, the co-solvent may be included in an amount ranging from 1 to 40% based on the total solvent volume.

[0079] When the first resist is formed from an aromatic vinyl-based polymer, as is typical for KrF and EUV photoresists, and the resist is developed as a PTD resist, the solvent system preferably includes one or more non-polar organic solvents. The term "non-polar organic system" means that the solvent system includes more than 50% by weight of total non-polar organic solvents based on the total solvents of the solubility modifier composition, and more typically includes more than 70%, 85% or 100% by weight of total non-polar organic solvents based on the total solvents of the solubility modifier composition. The non-polar organic solvents are typically present in the solvent system in a total amount of 70-98% by weight, preferably 80-95% by weight, more preferably 85-98% by weight, based on the solvent system.

[0080] Suitable non-polar 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.

[0081] In some embodiments, the solvent system further comprises one or more alcohol solvents and / or ester solvents. In certain compositions, the alcohol solvents and / or ester solvents may provide improved solubility for the solid components of the composition. Suitable alcohol solvents include, for example, 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, Linear, branched or cyclic C4-9 monohydric alcohols such as 3,3,4,4,5,5-octafluoro-1-pentanol and 2,2,3,3,4,4,5,5,6,6-decafluoro-1-hexanol; and C5-9 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. The alcohol solvent is preferably a C4-9 monohydric alcohol, and 4-methyl-2-pentanol is preferred. 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% by weight, more typically 2 to 30% by weight, based on the solvent system.

[0082] The solvent system may also include one or more additional solvents selected from 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. Such additional solvents, if used, are typically present in a total amount of 1 to 20% by weight based on the solvent system.

[0083] 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 70-98% by weight based on the solvent system, and one or more alcohol solvents and / or ester solvents in a total amount of 2-30% by weight based on the solvent system. The solvent system is typically present in the overcoat composition in an amount of 90-99% by weight, preferably 95-99% by weight, based on the overcoat composition.

[0084] In one or more embodiments, the first resist is an NTD resist and the solvent is a non-polar organic solvent. Suitable non-polar organic solvents include, but are not limited to, n-butyl acetate, 2-heptanone, propylene glycol methyl ether, propylene glycol methyl ether acetate, and combinations thereof.

[0085] In some embodiments, the solubility modifier is coated on the first relief pattern. To properly coat the first relief pattern, the solubility modifier may include a matrix polymer. The matrix polymer allows the composition to be coated on the resist pattern in the form of a layer with a desired thickness. This helps to ensure that there is a sufficient content of the solubility modifier to interact with the first resist surface. Any matrix polymer commonly used in the art may be included in the solubility modifier material. The matrix polymer should have good solubility in a solvent that does not dissolve the first resist. The matrix polymer may be formed from one or more monomers selected from (meth)acrylate monomers such as isopropyl (meth)acrylate and n-butyl (meth)acrylate, (meth)acrylic acid, styrene, hydroxystyrene, aromatic vinyl monomers such as vinyl naphthalene and acenaphthylene, vinyl alcohol, vinyl chloride, vinyl pyrrolidone, vinyl pyridine, vinyl amine, vinyl acetal, maleic anhydride, maleimide, norbornene, and combinations thereof, and the like, having ethylenically unsaturated polymerizable double bonds. In some embodiments, the polymer comprises one or more functional groups selected from hydroxy, carboxyl, acid groups such as sulfonic acid and sulfonamide, silanol, 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 different repeat units, such as two, three, four or more different repeat units. In one aspect, the repeat units of the polymer are formed entirely from (meth)acrylate monomers, or entirely from aromatic (vinyl) monomers, or entirely from (meth)acrylate monomers and aromatic (vinyl) monomers. When the polymer comprises more than one type of repeat unit, it typically takes the form of a random copolymer.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.

[0086] The solubility modifier composition typically includes a single polymer, but may optionally include one or more additional polymers. The content of polymer in the composition depends, for example, on the target thickness of the layer, with higher polymer contents being used when thicker layers are desired. The polymer is typically present in the pattern solubility modifier composition in an amount of 80-99.9 wt%, more typically 90-99 wt%, or 95-99 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 3000-50,000, more preferably 3000-25,000, as measured by GPC against polystyrene standards. Typically, the polymer has a polydispersity index (PDI=Mw / Mn) of 3 or less, preferably 2 or less, as measured by GPC against polystyrene standards.

[0087] Suitable polymers for use in the solubility modifier composition are commercially available and / or can be easily made 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 thereto, and carrying out thermal polymerization to form the polymer. Examples of suitable organic solvents that can be used for polymerizing 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.

[0088] The solubility modifier including the matrix polymer can be coated onto the first relief pattern according to methods known in the art. Typically, the solubility modifier including the matrix polymer can be coated onto the first relief pattern by spin coating. The solids content of the solubility modifier can be adjusted to provide a desired thickness of film of the solubility modifier on the first 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 time it can be spun. Typical thicknesses of the composition are from about 200 Å to about 1500 Å.

[0089] In one or more embodiments, the 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% to about 10% by weight of solids and about 90% to about 99% by weight of solvent, based on the total weight of the solubility modifier, the solids including the active agent and the matrix polymer. Within the solids content, the active agent may be included in an amount ranging from about 1% to about 5% by weight.

[0090] The solubility modifier may include 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, especially when thin gaps between features of the first resist need to be filled. Any suitable surfactant known in the art may be included in the solubility modifier.

[0091] As described above, in one or more embodiments, the solubility modifier is diffused into the first relief pattern and included in the first resist as an absorbing material. Diffusion of the solubility modifier into the first relief pattern may be accomplished by performing a thermal pretreatment, such as a bake. The bake may be a soft bake. The temperature and time of the soft bake may depend on the identity of the first resist and the desired amount of diffusion of the solubility modifier into the first resist. Typically, the soft bake may be performed at a temperature ranging from about 50° C. to about 150° C. for about 30 seconds to about 90 seconds.

[0092] After diffusion into the first resist, the coating layer may remain on the first resist without any effective solubility modifying material. In one or more embodiments, the coating layer may be removed by rinsing. Rinsing may be accomplished by rinsing the coated substrate with a solvent that dissolves the coating layer but not the first resist. Rinsing may be performed using any suitable method, such as immersing the substrate in a bath filled with the solvent for a certain period of time (dipping method), lifting the solvent on the substrate surface by the action of surface tension and leaving it to stand for a certain period of time to dissolve the coating layer (puddling method), spraying the solvent on the substrate surface (spraying method), or continuously spraying the solvent onto the substrate rotating at a constant speed while scanning the solvent spray nozzle at a constant speed (dynamic dispensing method).

[0093] In block 306 of method 300, a second resist or solubility modifiable polymer is deposited on the substrate. A coated substrate laminated with a first relief pattern 404, a solubility modifier 405, and a second resist 406 is shown in FIG. 4C. The second resist may be deposited on the substrate such that it fills the gaps of the first relief pattern and is in contact with the first relief pattern or the solubility modifier. In one or more embodiments, the second resist completely covers the substrate, the first relief pattern, and the solubility modifier. The second resist may be deposited on the substrate according to any suitable method known in the art, such as, for example, spin-on deposition or vapor phase processing.

[0094] Suitable second resist compositions include those listed above for the first resist composition. In one or more embodiments, the second resist comprises a polymer as described above. The second resist can be different from the first resist. For example, if the first resist is an organic-based resist, the second resist can be metal-based or silicon-based. Similarly, if the first resist is a metal-based resist, the second resist can be silicon-based. In one or more embodiments, the second resist can have a second etch selectivity, and thus can be somewhat more easily etched than the first resist. In some embodiments, the second resist does not include an etch resistance enhancer.

[0095] The polymer included in the second resist may have a weight average molecular weight (Mw) in the range of about 2,000 g / mol to about 20,000 g / mol. For example, in one or more embodiments, the second resist may include a polymer having a Mw in the range of a lower limit of about 2,000 g / mol, about 2,500 g / mol, about 3,000 g / mol, about 3,500 g / mol, about 4,000 g / mol, and about 5,000 g / mol to an upper limit of about 5,000 g / mol, about 7,500 g / mol, about 10,000 g / mol, about 12,500 g / mol, about 15,000 g / mol, about 17,500 g / mol, and about 20,000 g / mol (any lower limit may be paired with any mathematically compatible upper limit). Polymers having such Mw may exhibit desirable dissolution properties, particularly dissolution rate.

[0096] In one or more embodiments, the second resist includes a base. In such embodiments, the base may be included in the second resist in an amount ranging from 0.01% to 1.0% by weight based on the total weight of the second resist. Suitable bases include those listed above with respect to the base solubility modifier.

[0097] In one or more embodiments, the second resist comprises a photoacid selected from those listed above for the first resist composition.

[0098] In embodiments where the solubility modifier comprises a base or base generator and the first resist may be processed similarly to an NTD resist, the second resist comprises an acid and / or acid generator, which may be as described above for the acid or acid generator included in the solubility modifier.

[0099] At block 308 of the method 300, the solubility modifier is diffused into the second resist. In one or more embodiments, the diffusion of the solubility modifier into the second resist is accomplished by performing a bake. The bake may be performed on a hot plate or in an oven. The temperature and time of the bake may depend on the identity of the second resist and the desired amount of diffusion of the solubility modifier into the second resist. Suitable conditions for the bake may include a temperature ranging from 50° C. to 160° C. and a time ranging from about 30 seconds to about 90 seconds.

[0100] In one or more embodiments, after baking, the solubility modified region is present around the edge of the second resist. The amount of diffusion of the solubility modifier may correspond to the thickness of the solubility modified region. In some embodiments, the solubility modified region extends into the second resist to have a thickness of about 5 nm to about 60 nm. For example, the thickness of the solubility modified 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 (any lower limit may be paired with any mathematically compatible upper limit). In one or more embodiments, the thickness of the solubility modified region may correspond to a desired line width to be cut into the substrate.

[0101] A coated substrate including a solubility-modified region is shown in FIG. 4D. As shown in FIG. 4D, the coated substrate includes a target layer 402. The substrate is as previously described. A first relief pattern 404, comprised of a first resist 203, overlies the target layer 402. The first relief pattern 404 is coated with a solubility modifier. A second resist 406 is coated over the first relief pattern and the substrate. In one or more embodiments, the second resist 406 completely covers the substrate 402 and the first relief pattern 404. A solubility-modified region 408 of the second resist is shown adjacent to the first relief pattern.

[0102] The solubility-modified regions may have a different solubility than regions of the second resist that were not exposed to the solubility-modifying agent. Thus, the solubility-modified and unexposed regions of the second resist may be soluble in different resist developers.

[0103] In block 310 of the method 300, the deposited second resist layer may be developed using a specific developer such that the unexposed areas of the second resist remain. In one or more embodiments, the solubility-modified areas of the second resist are developed by first exposing them to actinic radiation and then exposing them to a specific developer. In other embodiments, the solubility-modified areas of the second resist are only exposed to a specific developer. The specific developer may depend on the tone of the second resist. For example, if the solubility modifier is an acid or an acid generator, the specific developer may be a base, such as tetramethylammonium hydroxide. On the other hand, if the solubility modifier includes a base or a base generator, the specific developer may be an organic solvent, such as n-butyl acetate or 2-heptanone.

[0104] The thickness of the solubility-modified region may correspond to the desired line width of the pattern to be cut into the substrate. FIG. 4E shows a coated substrate developed according to an embodiment of the present disclosure. In one or more embodiments, the second resist 406 is developed to dissolve the solubility-modified region between the first relief pattern and the second resist. Thus, dissolution of the solubility-modified region may form a trench 410 between the first relief pattern 404 and the second resist 406, where the target layer 402 is exposed. In some embodiments, an etch may be performed at this stage to transfer the pattern of the trench 410 into the target layer 402.

[0105] At block 312, the method 300 includes filling the gaps formed between the second resist and the first relief pattern with a fill material. Suitable fill materials include, but are not limited to, polysilicon, metals such as copper (Cu), nickel (Ni), cobalt (Co), iron (Fe), manganese (Mn), chromium (Cr), titanium (Ti), tantalum (Ta), ruthenium (Ru), palladium (Pd), tungsten (W) and various alloys, stacks or other combinations thereof, oxides of silicon (e.g., silicon dioxide (SiO2)), doped oxides of silicon, fluorinated oxides of silicon, carbon doped oxides of silicon, nitrides of silicon (e.g., SiO2), silicon nitrides (e.g., SiO2), silicon oxides ... For example, the fill material may be silicon nitride (SiN), carbide of silicon (e.g., silicon carbide (SiC)), carbonitride of silicon (e.g., SiCN), oxide of aluminum (e.g., aluminum oxide (Al2O3)), oxide of titanium (e.g., titanium oxide (TiO2)), oxide of zirconium (e.g., zirconium oxide (ZrO2)), oxide of hafnium (e.g., hafnium oxide (HfO2)), silicon antireflective coating, spin-on metal hard mask, various low-k dielectric materials known in the art, and combinations thereof. The fill material may be applied using a liquid phase technique such as spin coating, or a gas phase technique such as chemical vapor deposition, atomic layer deposition, molecular layer deposition, etc. In one or more embodiments, the fill material may have a third etch selectivity, such that it may be somewhat more easily etched than the first and second resists.

[0106] Any overburden may then be removed using chemical mechanical planarization to provide an ABC patterned multiline layer. Figure 4F shows an exemplary ABC patterned multiline layer. In Figure 4F, a target layer 402 is coated with a first resist 403, a second resist 406, and a fill material 412, such that the fill material is present at every other location and the first resist and second resist alternately occupy the spaces between the fill materials.

[0107] Method 300 represents one possible embodiment and is not intended to limit the scope of the invention. As will be appreciated by those skilled in the art, the invention may encompass a variety of alternative methods, such as, for example, a method in which the solubility modifier is diffused into the first resist rather than the second resist. In such alternative embodiments, the components and techniques used in the method may be as described above with reference to method 300.

[0108] As described above, in one or more embodiments, the solubility modifier is diffused into the first resist. In such an embodiment, the method may include first forming a first relief pattern of the first resist and then coating the first resist with a solubility modifier. At this point, the solubility modifier may be diffused a predetermined distance into the first resist to provide a region of modified solubility in the first resist. Although the diffusion of the solubility modifier may occur into different components at different times in such a method, the diffusion of the solubility modifier may be performed as described above in method 300. After the solubility modifier is diffused into the first resist, a second resist may be deposited on the substrate. The method may then continue according to method 300.

[0109] Additionally, although the method 300 ends with the ABC multiline pattern including the first resist, the second resist, and the fill material, alternative methods may continue by selectively removing certain materials and replacing them with replacement materials. As will be appreciated by those skilled in the art, any of the first resist, the second resist, and the fill material may be removed by a target developer, rinse, or other method and replaced with a suitable replacement material. The suitable replacement material may be a different resist or fill material having a fourth etch selectivity that is either higher or lower than the etch selectivity of the first and second resists and the fill material.

[0110] In one or more embodiments, processing may continue using AB patterned multi-layer lines, hi some embodiments, additional processing may include repeating various steps of method 300 to provide ABC patterned multi-layer lines.

[0111] Another method 500 of providing an ABC patterned multiline layer according to the present disclosure is shown in Figure 5. Schematic diagrams of a coated substrate at various points in method 500 are shown in Figures 6A-6D. In method 500, at block 502, an AB patterned multiline layer is provided on a target layer according to method 300, again with reference to Figure 3. As will be appreciated by those skilled in the art, the components and methods used in method 300 may be applied to method 500 as described with reference to method 300. In Figure 6A, a coated substrate is shown having an intermediate target layer underlying the AB patterned multiline layer.

[0112] In block 504, the first resist may be removed. The first resist may be removed according to techniques known in the art. In one or more embodiments, the first resist is removed by performing a rinse, wet chemical etching, or dry etching process. As shown in FIG. 6B, removal of the first resist may provide a pattern defined by the second resist and the fill material, including trenches between the fill material, where the target layer is exposed. Then, in block 506 of the method 500, as shown in FIG. 6C, the pattern defined by the second resist and the fill material is transferred to the underlying target layer such that trenches are formed in the underlying target layer. Finally, in block 508, the trenches in the underlying target layer are filled with a second fill material to provide an ABC patterned multiline layer. An exemplary ABC patterned multiline layer is shown in FIG. 6D.

[0113] As will be appreciated by one of ordinary skill in the art, although method 500 includes removing the first resist to provide a relief pattern defined by the second resist and the fill material, alternative embodiments may include removing the second resist to provide a relief pattern defined by the first resist and the fill material, in such embodiments, after removal of the second resist, the method may proceed as described above in method 500.

[0114] In one or more embodiments, after filling with the fill material, the first resist and the second resist are removed and replaced with a replacement material. The replacement material can be a material selected from the fill materials described herein. Any overburden of the replacement material can be etched or planarized to the top of the fill material to complete the multi-line layer for continued patterning.

[0115] The methods and systems of one or more embodiments rely on both chemical processes and diffusion characteristics to provide a unique ability to apply control functions to the input chemical reactions themselves, and the processes for measuring such chemical reactions.

[0116] Although 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 substantially departing from 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. providing a first relief pattern on a target layer, the first relief pattern comprising a first resist having a first etch selectivity; coating the first relief pattern with a solubility modifier; depositing a second resist on the first relief pattern such that the second resist is in contact with the first relief pattern, the second resist having a second etch selectivity different from the first etch selectivity; diffusing the solubility modifier a predetermined distance into the second resist to provide a solubility modified region of the second resist, the solubility modified region of the second resist adjacent the first relief pattern; developing the second resist such that the solubility-altered regions are dissolved to provide gaps between the first relief pattern and the second resist where portions of the target layer are exposed; filling the gap between the first relief pattern and the second resist with a fill material; A microfabrication method comprising:

2. providing a first relief pattern on a target layer, the first relief pattern comprising a first resist having a first etch selectivity; coating the first relief pattern with a solubility modifier; diffusing the solubility modifying agent a predetermined distance into the first resist to provide a solubility modified region of the first resist; depositing a second resist on the first relief pattern such that the second resist is in contact with the first relief pattern, the second resist having a second etch selectivity different from the first etch selectivity; developing the first resist such that the solubility-altered regions are dissolved to provide gaps between the first relief pattern and the second resist where portions of the target layer are exposed; filling the gap between the first relief pattern and the second resist with a fill material; A microfabrication method comprising:

3. The method of claim 1 or 2, wherein the target layer is an intermediate layer on a substrate.

4. transferring a pattern defined by the first relief pattern and the second resist into the target layer prior to filling the gap between the first relief pattern and the second resist; filling the gap in the target layer with the filler material; The method of claim 3 further comprising:

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

6. The method of claim 1 or 2, wherein the second resist fills the gaps in the first relief pattern.

7. The method of claim 1 or 2, wherein the fill material is selected from the group consisting of polysilicon, silicon dioxide and tungsten.

8. removing the first relief pattern; and transferring a pattern defined by the second resist and the fill material into the target layer; filling the target bed with a second fill material; The method of claim 1 or 2, further comprising:

9. The method of claim 8 further comprising removing material above the target layer.

10. removing the second resist; and transferring a pattern defined by the first resist and the fill material into the target layer; filling the target bed with a second fill material; The method of claim 1 or 2, further comprising:

11. The method of claim 1 or 2, wherein the first resist comprises an organometallic containing metal oxide nanoparticles.

12. The method of claim 11 , wherein the second resist comprises a silicon-based resist.

13. The method of claim 1 or 2, wherein the first resist comprises a polymer including monomer units selected from the group consisting of acrylates, methacrylates, p-hydroxystyrene, styrene, norbornene, and combinations thereof.

14. The method of claim 13 , wherein the second resist comprises an organometallic containing metal oxide nanoparticles.

15. The method of claim 13 , wherein the second resist comprises a silicon-based resist.

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

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

18. 17. The method of claim 16, wherein the acid generator is selected from the group consisting of triphenylsulfonium antimonate pyridinium perfluorobutanesulfonate, 3-fluoropyridinium perfluorobutanesulfonate, 4-t-butylphenyl tetramethylenesulfonium perfluoro-1-butanesulfonate, 4-t-butylphenyl tetramethylenesulfonium 2-trifluoromethylbenzenesulfonate, 4-t-butylphenyl tetramethylenesulfonium 4,4,5,5,6,6-hexafluorodihydro-4H-1,3,2-dithiazine 1,1,3,3-tetraoxide, and combinations thereof.

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

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

21. 20. The method of 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.

22. 3. The method of claim 1 or 2, wherein the solubility modifier comprises a matrix polymer comprising monomers having ethylenically unsaturated polymerizable double bonds, including (meth)acrylate monomers; (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.

23. 3. The method of claim 1 or 2, wherein the solubility modifier comprises a matrix polymer comprising monomers containing one or more functional groups selected from hydroxy, carboxyl, sulfonic acid, sulfonamide, silanol, fluoroalcohol, anhydride, lactone, ester, ether, allylamine, pyrrolidone, and combinations thereof.

24. 3. The method of claim 1 or 2, further comprising diffusing the solubility modifier into the first relief pattern immediately after coating the first relief pattern with the solubility modifier.

25. 25. The method of claim 24, wherein diffusing the solubility modifier into the first relief pattern is accomplished by performing a bake.

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