Optimization for local chemical exposure

Abstract

A microfabrication method includes depositing a first layer of a first resist including a first chemical marker on a substrate, measuring a first fluorescence intensity of the first layer from the first fluorescent chemical marker, forming a first relief pattern from the first layer of the first resist, and measuring a second fluorescence intensity of the first layer from the first chemical marker after forming the first relief pattern. The method then includes depositing a solubility modifier on the first relief pattern, depositing a second resist on the first relief pattern, 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 of the second resist are dissolved to expose portions of the substrate, and measuring a third fluorescence intensity of the first layer from the first chemical marker.

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 a 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, covering the portions of the substrate that will not be etched when the substrate is subjected to one or more etching processes. Processing then continues with additional steps such as material deposition, etching, annealing, photolithography, and the various steps can be repeated until a transistor or integrated circuit is produced. Summary of the Invention [Means for solving the problem]

[0002] 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.

[0003] In one aspect, embodiments disclosed herein relate to a microfabrication method that includes depositing a first layer of a first resist on a substrate, the first resist including a first fluorescent chemical marker; measuring a first fluorescence intensity of the first layer from the first fluorescent chemical marker; forming a first relief pattern from the first layer of the first resist after measuring the first fluorescence intensity of the first layer; and measuring a second fluorescence intensity of the first layer from the first chemical marker after forming the first relief pattern. The method then includes depositing a solubility modifier on the first relief pattern; depositing a second resist on the first relief pattern; diffusing the solubility modifier a predetermined distance into the second resist to provide a solubility-modified region of the second resist, wherein the solubility-modified region of the second resist is adjacent to the first relief pattern; developing the second resist such that the solubility-modified region of the second resist is dissolved to provide an opening between the first relief pattern and the second resist, exposing a portion of the substrate therein; and measuring a third fluorescence intensity of the first layer from the first chemical marker after forming the first relief pattern from the first layer.

[0004] In another aspect, embodiments disclosed herein relate to a microfabrication method that includes depositing a first layer of a first resist on a substrate, the first resist including a first fluorescent chemical marker; measuring a first fluorescence intensity of the first layer from the first fluorescent chemical marker; forming a first relief pattern from the first layer of the first resist after measuring the first fluorescence intensity of the first layer; and measuring a second fluorescence intensity of the first layer from the first chemical marker after forming the first relief pattern. The method then includes depositing a solubility modifier on the first relief pattern, diffusing the solubility modifier a predetermined distance into the first resist to provide solubility-modified regions of the first resist, depositing a second resist on the first relief pattern, developing the first resist such that the solubility-modified regions of the first resist are dissolved to provide openings between the first relief pattern and the second resist exposing portions of the substrate, and measuring a third fluorescence intensity of the first layer from the first chemical marker after developing the first resist.

[0005] Other aspects and advantages of the claimed subject matter will become apparent from the following description and appended claims. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a block flow diagram of a method according to one or more embodiments of the present disclosure.

[0007] [Figure 2A] 1A-1D are schematic illustrations of a coated substrate at various points in a method according to one or more embodiments of the present disclosure. [Figure 2B] 1A-1D are schematic illustrations of a coated substrate at various points in a method according to one or more embodiments of the present disclosure. [Figure 2C] 1A-1D are schematic illustrations of a coated substrate at various points in a method according to one or more embodiments of the present disclosure. [Figure 2D]1A-1D are schematic illustrations of a coated substrate at various points in a method according to one or more embodiments of the present disclosure. [Figure 2E] 1A-1D are schematic illustrations of a coated substrate at various points in a method according to one or more embodiments of the present disclosure. [Figure 2F] 1A-1D are schematic illustrations of a coated substrate at various points in a method according to one or more embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0008] In the field of lithography, surface-driven chemical exposure is a novel method for creating small features and optimizing substrate patterning performance and capabilities. Surface-driven chemical exposure and diffusion of various chemicals for solubility modification allows access to dimensions in the single nanometer range, well below the resolution of conventional 193 nm lithography. Similar to optical lithography, various process control steps exist to control the final dimensional capabilities. Such a process ideally controls initial layer formation, concentration control, dimensional feedback, and final process feedback functions, allowing for flexible capabilities to control the final dimension beyond just the processed CD (Critical Dimension).

[0009] Accordingly, the present disclosure generally relates to methods and systems for process control. Such methods and systems may include novel target designs, novel feedback mechanisms, novel control points embedded within integrated flows to optimize novel integration strategies, and novel targets and chemistries designed to simplify measurement, particularly to optimize techniques such as fluorescence or imaging. The systems and methods described herein may be used with conventional semiconductor manufacturing tools and equipment.

[0010] The methods and systems described herein can be used for a variety of control and monitoring requirements. In one or more embodiments, process control is enabled for chemical spacers, including simple spacers and cross spacers, such as spacers that cross on various planes. In some embodiments, process control is enabled for selective and double patterning, including, for example, single patterning, double selectors, and line contact / stitching.

[0011] In one or more embodiments, the method involves measuring the projected area, volume, or shape of each feature, and then using such measurements to appropriately control thickness, thermal or optical activation, and environment (which can control top overhang) in a feedback system. By controlling these dimensions, the final shape of the resulting features can be controlled.

[0012] The method and system of one or more embodiments provides the unique ability to apply control functions to the input chemical reactions themselves and the process of measuring such chemical reactions, relying on both chemical process and diffusion characteristics.

[0013] For example, the anti-spacer process flow is a track-based process that creates narrow trenches by acid diffusion from the structures of a first relief pattern into a second material that fills the openings defined by the first relief pattern. Acid diffusion is precisely controlled by exposure dose, time, temperature, and material composition. Thus, sub-resolution trenches down to single-digit nanometer dimensions can be created.

[0014] As with conventional micro-fabrication processes, metrology is useful in this micro-fabrication method to identify any processing steps that require correction. For example, in the anti-spacer method, various measurement options and various controls exist, as briefly described above. As with conventional double patterning control schemes, in this method, the post-resist diameter can be measured using any metrology technique conventionally used in the art, such as scatterometry, electron microscopy, and scanning probe microscopy (SPM).

[0015] The microfabrication method may include feedback for anti-spacer (e.g., gaps between features in one or more relief patterns) formation, because such feedback may alter development / activation or diffusion amount / composition depending on the material, equipment, and other random effects. Therefore, it is beneficial to have a control method to ensure that the features formed have the desired size and shape. For typical spacer formation, metrology is different. Sidewall spacers are typically formed by vapor-based conformal deposition on inorganic materials, followed by a directional etch (spacer-open etch) to remove material from the top of the mandrel and floor material. Metrology is then performed to measure the CD of the created sidewall spacers. However, anti-spacers primarily created in a track tool or coater developer require a different metrology solution. The methods disclosed herein provide the ability to monitor the process flow of track-based processes at any point during such processes.

[0016] As described above, anti-spacer technology is a track-based process. A typical microfabrication process using anti-spacer technology first involves forming a first relief pattern on a substrate. The first relief pattern may include a first resist. The first relief pattern may be formed by first depositing the first resist on the substrate, then exposing the first resist to a pattern of actinic radiation, and finally developing the first resist to leave specific features on the substrate. Such features constitute the first relief pattern.

[0017] A solubility modifier, such as an acid, can then be coated onto the first relief pattern. The solubility modifier can be absorbed into the first relief pattern. A second resist can then be deposited onto the first relief pattern. The second resist can fill any gaps in the first relief pattern. The solubility modifier absorbed into the first relief pattern can then diffuse into the second resist, such that the portions of the second resist exposed to the solubility modifier can have a different solubility than the portions of the second resist not exposed to the solubility modifier. The exposed portions of the second resist can become soluble in a specific developer subsequently used to develop the second resist. In this way, the exposed portions of the second resist can be dissolved, exposing portions of the substrate. Finally, the exposed portions of the substrate can be etched.

[0018] Alternatively, when a solubility modifier is absorbed into a first resist, it may induce a solubility modification in the areas of the first resist where it is absorbed. Such a solubility modification may provide solubility-modified areas of the first resist that are soluble in a particular developer. Thus, deposition of a second resist and development with the particular developer may result in dissolution of the solubility-modified areas of the first resist and exposure of the substrate.

[0019] Desired output variables for the anti-spacer method include the width of the first resist feature, the width of the anti-spacer, and the width of the undeveloped portion of the second resist. Secondarily, the 2D / 3D shape is also important for the final etch dimensions.

[0020] In one or more embodiment methods, individual layers include metrology-specific chemical features in their composition to provide control over the material. In one or more embodiments, the method includes adding metrology-specific chemicals to one or more materials, such as the first resist, the second resist, among others. For example, the resist on the substrate can have a specific chemical marker (activated or not). An exemplary chemical marker can be a fluorescent chemical marker, such as a specific dye. By measuring the change in the fluorescence spectrum of the dye, the total volume of the resist can be measured.

[0021] A process control method according to an embodiment of the present disclosure is shown in and will be discussed with reference to FIG. 1. Initially, the method 100 includes, in block 102, providing a first layer of a first resist on a substrate. As used herein, the terms "semiconductor substrate" and "substrate" are used interchangeably and may refer to any semiconductor material, including, but not limited to, a semiconductor wafer, a semiconductor material layer, and combinations thereof. The first resist may include a first fluorescent chemical marker. In block 104, a fluorescence intensity of the first resist from the first fluorescent chemical marker is measured. Then, in block 106, the first layer of the first resist is photolithographically developed to form a first relief pattern, and a second fluorescence intensity is measured in block 108.

[0022] In block 110, the first relief pattern is coated with a solubility modifier. The solubility modifier can be a solubilizer or a hardener, depending on the polarity of the first resist. Then, in block 112, a second resist is layered over the first relief pattern, so that the substrate and exposed portions of the first resist are completely covered with the second resist. In block 114, the solubility modifier is then diffused into the second resist, and in block 116, the second resist is developed. The diffusion of the solubility modifier can form solubility-modified regions of the second resist, which can be selectively developed to form trenches exposing the substrate. After developing the second resist, in block 118, the fluorescence intensity of the first fluorescent chemical marker is measured to determine the critical dimension of the first resist.

[0023] Schematic illustrations of a coated substrate at various points during the above-described method are shown in Figures 2A, 2B, 2C, 2D, 2E, and 2F. 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. Figure 2A shows a substrate that has been photolithographically developed to provide a first relief pattern. Figure 2B shows a substrate that has been coated with a solubility modifier and includes a first relief pattern. Figure 2C shows the first relief pattern with the solubility modifier absorbed. Figure 2D shows a second resist being deposited on the substrate and the first relief pattern. Figure 2E shows the coated substrate after the solubility modifier has diffused into the second resist. Finally, Figure 2F shows the coated substrate after the second resist has been developed, resulting in the formation of an anti-spacer pattern. The method of Figure 1 and the coated substrates shown in Figures 2A-2F are discussed in more detail below.

[0024] In block 102 of the method 100, a first layer of a first resist is provided. FIG. 2A shows an example of a first layer 204 on a substrate 202. The first layer can be made of a first resist 203. The first resist can be a photoresist. Generally, a photoresist is a chemically amplified photosensitive composition including 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, but can particularly be a polymer having acid-labile groups. For example, the polymer can be a polymer made from monomers including styrene, p-hydroxystyrene, acrylates, methacrylates, norbornene, 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 included in the first resist. As will be appreciated by those skilled in the art, various protecting groups can be used for this purpose. Examples of acid labile groups include tertiary alkyl ester groups, secondary or tertiary aryl ester groups, secondary or tertiary ester groups having a combination of an alkyl group and an aryl group, 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 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 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 3-20Cycloalkenyl, 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 one or more groups selected from -O-, -C(O)-, -C(O)-O-, or -S- as part of its structure, and any two R 1 The 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 3-20 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 C1-6 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 one or more groups selected from -O-, -C(O)-, -C(O)-O- or -S- as part of its structure, and one R 2 is R 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.

[0026] The polymer may further comprise a monomer containing an acid labile group that, upon polymerization, decomposes to form an alcohol or fluoroalcohol group on the polymer. Suitable such groups include, for example, groups 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 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.

[0027] In an embodiment in which the first resist is a photoresist, the first resist contains a photoacid generator. The photoacid generator is a compound capable of generating an acid upon exposure to actinic rays or radiation. The photoacid generator can be selected from known compounds capable of generating an acid upon exposure to actinic rays or radiation, such as those used as photoinitiators for cationic photopolymerization, photoinitiators for radical photopolymerization, photobleaching agents 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.

[0028] 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 also known as photoacid generators. They are also known to function as catalytic 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; Examples of suitable non-polymeric photoacid generators include oxime 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-polymeric 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. 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.

[0029] 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.

[0030] In one or more embodiments, the first resist includes a first fluorescent chemical marker. The fluorescent chemical marker can be any suitable fluorescent chemical that can be included in a resist composition. Suitable fluorescent chemicals can fluoresce at wavelengths ranging from about 200 nm to about 5000 nm. For example, suitable fluorescent chemicals can have a fluorescent wavelength ranging from a lower limit of one of about 200 nm, about 220 nm, about 250 nm, about 280 nm, about 300 nm, about 350 nm, and about 400 nm to an upper limit of one of about 500 nm, about 1000 nm, about 2000 nm, about 3000 nm, about 4000 nm, and about 5000 nm (any lower limit can be paired with any mathematically compatible upper limit).

[0031] In one or more embodiments, the fluorescent chemical marker is about 10 -7 mol / liter ~ approx. 10 -2The fluorescent chemical marker may be included in the first resist in an amount ranging from about 10 mol / liter. -7 mol / liter ~ approx. 10 -6 The fluorescent chemical marker is added in a concentration of mol / liter, so that a relatively small amount of the fluorescent chemical marker is sufficient for measurement and the fluorescent chemical marker does not affect the functional performance of the first resist.

[0032] In one or more embodiments, the fluorescent chemical marker may be a fluorescent dye. Suitable fluorescent dyes include pyrene, BODIPY dyes, cyanine 3 dyes, cyanine 5 dyes, cyanine 5.5 dyes, cyanine 7 dyes, fluorescein dyes, rhodamine dyes, coumarin dyes, 800CW dyes, BP Fluor 680, BP Fluor 647, BP Fluor 594, BP Fluor 568, BP Fluor 546, BP Fluor 555, BP Fluor 350, BP Fluor 488, BP Fluor 430, BP Fluor 532, 4-(9H-carbazol-9-yl)benzoate, and 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)4H-pyran. In other embodiments, fluorescent chemical markers such as those listed above may be included as functional groups on the polymer of the first resist.

[0033] At block 104 of method 100, an initial fluorescence intensity of the first layer of the first resist is measured. The fluorescence may be measured according to methods known in the art, such as optical emission spectroscopy or laser-induced fluorescence spectroscopy, among others.

[0034] In some embodiments, the average fluorescence intensity is measured. The average fluorescence can be measured by taking fluorescence measurements over a large area, such as the entire substrate area. In other embodiments, the fluorescence intensity of a small target area is measured. The small target area can have a size ranging from about 5 μm x about 5 μm to about 50 μm x about 50 μm.

[0035] Then, in block 106, the first resist is developed to provide a first relief pattern. As shown in FIG. 2A, the first relief pattern may include features separated by gaps. Portions of the substrate may be exposed due to the presence of the gaps in the first relief pattern. The features of the first relief pattern may be made from the first resist 203 and, as such, may include a first fluorescent chemical marker.

[0036] The first relief pattern can be formed by laminating a first resist onto a substrate and developing the first resist. The first resist can 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 can 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 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. 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 some 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 monomers described above, where any monomers containing reactive functional groups are protected. Thus, the PTD first 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).

[0038] In other embodiments, the first resist is a negative resist. In such embodiments, the first relief pattern can include a polymer made from the monomers described above, where any monomers containing reactive functional groups are unprotected. Exposure to actinic radiation causes crosslinking of the polymer in the exposed areas, rendering the polymer insoluble in a developer. The unexposed and therefore uncrosslinked areas can then be removed using an appropriate developer to form the relief pattern.

[0039] 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 monomers described above, in which any monomers containing reactive functional groups are protected. Thus, NTD first resists 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 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 chemical reaction applied to the first relief pattern.

[0040] In one or more embodiments, the first resist optionally includes other additives, including 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 plasticizer, a photosensitizer, a light absorber, an alkali-soluble resin, a dissolution inhibitor, and a compound for accelerating dissolution in a developer.

[0041] 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 Å to about 3000 Å. The gaps separating the features can leave a portion of the substrate exposed.

[0042] In some embodiments, the first relief pattern is stabilized before coating with the solubility modifier. Various resist stabilization techniques, also known as freeze-in 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.

[0043] A second fluorescence of the first resist may be measured at block 108 of the method 100. The fluorescence may be measured according to methods known in the art, as described above.

[0044] In block 110 of method 100, the first relief pattern is coated with a solubility modifier. The coated substrate according to block 108 is shown in FIG. 2B. Solubility modifier 205 is shown as coating on the first relief pattern 204 and the substrate. The thickness of the solubility modifier coating is not particularly limited and can be varied based on the desired anti-spacer 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 the solubility modifier into the first resist is described in detail below.

[0045] The composition of the solubility modifier may depend on the tone of the first resist. Generally, the solubility modifier may be any chemical that is activated by light or heat. For example, if the first resist is a PTD resist, the solubility modifier may include an acid or a thermal acid generator (TAG). The acid, or in the case of a TAG, the generated acid, should be sufficient to heat-decompose the acid-labile group bonds of the polymer in the surface region of the first resist pattern, thereby increasing the solubility of the first resist polymer in the specific developer being applied. The acid or TAG is typically present in the composition in an amount of about 0.01 to about 20 wt % based on the total solids content of the trimming composition.

[0046] Preferred acids include organic acids, including non-aromatic and aromatic acids, each of which can 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, malonic acid, and alkanoic acids including 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.

[0047] Exemplary fluorine-free aromatic acids include aromatic acids of the following general formula (I):

[0048] [ka]

[0049] 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; and a and b independently represent integers of 0 to 5, and a+b is 5 or less.

[0050] An exemplary aromatic acid may be of the following general formula (II):

[0051] [ka]

[0052] [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]

[0053] Additional aromatic acids that may be included in the solubility modifier include those of the following general formula (III) or (IV):

[0054] [ka]

[0055] [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; and k and 1 each independently represent an integer of 0 to 3, and k+l is 3 or less]

[0056] [ka]

[0057] [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]

[0058] Suitable aromatic acids may alternatively be of the following general formula (V):

[0059] [ka]

[0060] [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]

[0061] Further, exemplary aromatic acids can have the following general formula (VI):

[0062] [ka]

[0063] 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.

[0064] In one or more embodiments, the acid is a fluorine-substituted free acid. Suitable fluorine-substituted free acids can be aromatic or non-aromatic. For example, fluorine-substituted free acids that can be used as solubility modifiers include, but are not limited to:

[0065] [ka]

change

[0066]

change

change

change

[0067] 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.

[0068] Preferably, the TAG is ionic in the reaction scheme for generating sulfonic acid as shown below.

[0069] [ka]

[0070] 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):

[0071] (BH) + (I)

[0072] 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, 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 alkyl, aryl, halogen atoms (preferably fluorine), cyano, nitro, and alkoxy. Among these, base B is preferably a heteroaromatic base.

[0073] 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 value of the conjugate acid (BH) of the basic moiety (B) in aqueous solution at about room temperature. + In certain embodiments, base B has a boiling point of less than about 170°C, less than about 160°C, 150°C, 140°C, 130°C, 120°C, 110°C, 100°C, or less than 90°C.

[0074] Suitable exemplary nitrogen-containing cations (BH) + As for NH4 + , CF2HNH2 + , CF3CH2NH3+ , (CH3)3NH + , (C2H5)3NH + , (CH3)2(C2H5)NH + and the following:

[0075] [ka]

[0076] wherein Y is alkyl, preferably methyl or ethyl.

[0077] 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.

[0078] Alternatively, when the first resist is an NTD resist, the solubility modifier may include a base or a 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. The amines may be primary, secondary, or tertiary amines. The amines may be monoamines, diamines, or polyamines. 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, and tetrakis(2-hydroxypropyl)ethylenediamine; arylamines such as diphenylamine, triphenylamine, aminophenol, and 2-(4-aminophenyl)-2-(4-hydroxyphenyl)propane; Tröger'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 hydroxyamine.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.

[0079] 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.

[0080] In one or more embodiments, the solubility modifier comprises a solvent. As noted 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 solvent system containing one or more organic solvents. The term "organic" means that the solvent system contains 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.

[0081] 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-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-hexanol; alcohols, 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.

[0082] The solvent included 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 for absorption into a 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 included in the solvent in an amount ranging from 60 to 99% based on the total solvent volume. Thus, the cosolvent can be included in an amount ranging from 1 to 40% based on the total solvent volume.

[0083] 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 non-polar organic solvents. The term "non-polar organic system" means that the solvent system includes more than 50 wt. % total non-polar 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 non-polar organic solvents based on the total solvents in the solubility modifier composition. The non-polar 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.

[0084] 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.

[0085] In some embodiments, the solvent system further comprises one or more alcohol and / or ester solvents, which in 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 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.

[0086] The solvent system can 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, when used, are typically present in a total amount of 1 to 20% by weight based on the solvent system.

[0087] 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 wt % based on the solvent system, and one or more alcohol solvents and / or ester solvents in a total amount of 2 to 30 wt % based on the solvent system. The solvent system is typically present in the overcoat composition in an amount of 90 to 99 wt %, preferably 95 to 99 wt %, based on the overcoat composition.

[0088] In one or more embodiments, when the first resist is an NTD resist, suitable 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.

[0089] In some embodiments, the solubility modifier is coated onto the first relief pattern. To properly coat the first relief pattern, the solubility modifier may include a matrix polymer. Any matrix polymer commonly used in the art may be included in the solubility modifier. 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, 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, and the like, having an ethylenically unsaturated polymerizable double bond. 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 is typically in 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.

[0090] 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, and 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.

[0091] 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 thereto, and conducting thermal polymerization to form the polymer. Examples of suitable organic solvents that can be used for polymer polymerization 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.

[0092] 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 solubility modifier can be adjusted to provide a film of the desired thickness 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 allowed for spinning. Typical thicknesses of the composition are from about 200 Å to about 1500 Å.

[0093] 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 99% by weight of solvent, based on the total weight of the solubility modifier, 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% by weight.

[0094] The solubility modifier may include additives with various purposes depending on the particular chemistry used. In some embodiments, a surfactant may be included in the solubility modifier. The surfactant 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.

[0095] As described above, in one or more embodiments, the solubility modifier is imbibed into the first relief pattern. The imbibition 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 identity 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 seconds to about 90 seconds.

[0096] After absorption into the first resist, a coating layer that does not contain any effective solubility-modifying material may remain on the first resist. FIG. 2C shows a substrate including a first relief pattern with the solubility-modifying agent 205 absorbed therein, with the coating layer removed. 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 any suitable method, such as immersing the substrate in a bath filled with solvent for a certain period of time (dipping method), lifting the solvent onto the substrate surface by surface tension and leaving it to stand for a certain period of time to dissolve the coating layer (puddling method), spraying the solvent onto the substrate surface (atomization method), or continuously spraying the solvent onto a substrate that is rotating at a constant speed while scanning a solvent-spraying nozzle at a constant speed (dynamic dispensing method).

[0097] At block 112 of method 100, a second resist is deposited on the substrate. A coated substrate stacked with a first relief pattern 204, a solubility modifier 205, and a second resist 206 is shown in FIG. 2D. The second resist may be deposited on the substrate such that it fills gaps in 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.

[0098] In one or more embodiments, the second resist comprises a polymer. Suitable polymers can be as described above with respect to the polymers defined as the first resist polymer and / or 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 is 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 30% styrene, and about 10 to 30% t-butyl acrylate. For example, the polymerization reaction to produce the polymer included in the second resist may include p-hydroxystyrene in an amount ranging from a lower limit of about 50%, about 55%, about 60%, and about 65% to an upper limit of about 65%, about 70%, about 75%, and about 80% (any lower limit may be paired with any mathematically compatible upper limit), and styrene and t-butyl acrylate in individual amounts ranging from a lower limit 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% (any lower limit may be paired with any mathematically compatible upper limit).

[0099] The polymer included in the second resist can have a weight average molecular weight (Mw) ranging from about 1 kg / mol to about 100 kg / mol. For example, in one or more embodiments, the second resist can include a polymer having a Mw ranging from a lower limit of about 1 kg / mol, about 2 kg / mol, about 5 kg / mol, about 10 kg / mol, about 15 kg / mol, about 20 kg / mol, and about 25 kg / mol to an upper limit of about 25 kg / mol, about 50 kg / mol, about 75 kg / mol, about 80 kg / mol, about 90 kg / mol, and about 100 kg / mol (any lower limit can be paired with any mathematically compatible upper limit). Polymers with such Mw can exhibit desirable dissolution properties, particularly dissolution rate.

[0100] In one or more embodiments, the second resist includes a solvent. The solvent can be as described above for the solvent included in the solubility modifier. In certain embodiments, the solvent in the second resist is the same as the solvent in the solubility modifier.

[0101] The second resist may contain additives with various purposes, depending on the particular chemistry used. In some embodiments, a quencher is included in the second resist. The quencher may be included in the second resist to help control the diffusion of the active substance in the solubility-modifying material. Suitable quenchers include any of the bases listed above with reference to the solubility-modifying material.

[0102] The second resist can be a PTD resist or an NTD resist. Both PTD and NTD resists can include a polymer and a solvent as described above. In embodiments where the second resist is an NTD resist, it can also include an acid or acid generator. The acid or acid generator is as described above with reference to the solubility-modifying material.

[0103] At block 114 of method 100, 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 achieved by baking. 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 about 50° C. to about 160° C. and a time ranging from about 30 seconds to about 90 seconds. In one or more embodiments, after baking, a solubility-modified region may be 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 a thickness of about 5 to about 60 nm. For example, the thickness of the solubility-modified region may range from a lower limit of one of about 5 nm, about 10 nm, about 15 nm, about 20 nm, and about 25 nm to an upper limit of one of about 40 nm, about 45 nm, about 50 nm, about 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 the desired line width to be cut into the substrate.

[0104] As previously described, the thickness of the solubility-modified region can correspond to the desired width of the anti-spacer. A coated substrate including a solubility-modified region is shown in FIG. 2E. As shown in FIG. 2E, the coated substrate includes a substrate layer 202. The substrate is as previously described. A first relief pattern 204 composed of a first resist 203 and a first fluorescent chemical marker is located on the substrate 202. A second resist 206 is coated on the first relief pattern and the substrate. In one or more embodiments, the second resist 206 completely covers the substrate 202 and the first relief pattern 204. A solubility-modified region 208 of the second resist is shown adjacent to the first relief pattern.

[0105] 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.

[0106] In block 116 of method 100, the deposited layer of second resist can be developed using a specific developer to leave either the solubility-altered or unexposed areas of the second resist. In one or more embodiments, the solubility-altered 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-altered areas of the second resist are only exposed to the specific developer. The specific developer can depend on the tone of the second resist. For example, if the second resist is a positive-tone developing resist, the specific developer can be a base such as tetramethylammonium hydroxide. On the other hand, if the second resist is a negative-tone developing resist, the specific developer can be a non-polar organic solvent such as n-butyl acetate or 2-heptanone.

[0107] 2F shows the coated substrate developed according to embodiments of the present disclosure. In one or more embodiments, the second resist 206 is developed to dissolve the solubility-modified regions 208 between the first relief pattern and the second resist. Thus, dissolution of the solubility-modified regions can result in the formation of trenches 210 between the first relief pattern 204 and the second resist 206, exposing the substrate 202.

[0108] In method 100, referring again to FIG. 1, after developing the second resist, the final fluorescence intensity of the first resist is measured. As described above, the fluorescence intensity can be measured according to methods known in the art. The final fluorescence intensity can be compared to the initial fluorescence intensity to determine the critical dimensions of the first resist. In particular, the fluorescence intensity can be used to determine the total volume and surface absorbance of the first resist. For example, the original thickness, original fluorescence, and final fluorescence of the first resist can be used to calculate the volume change. Depending on the feature type (e.g., line or hole), the average size of the feature can also be calculated. The wavelengths that work or can be measured depend on the absorbance and fluorescence of the material.

[0109] Method 100 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 one in which the solubility modifier is diffused into the first resist rather than the second resist. Furthermore, some methods may include adding fluorescent chemicals to materials other than the first resist so that they are present in some layer of the coated substrate stack to provide information and control over the process. In such alternative embodiments, the components and techniques used in the method may be as described above with reference to method 100.

[0110] In one or more embodiments, various fluorescent chemical markers may be used in different layers of the coated substrate depending on the critical dimension to be determined. For example, in some embodiments, a first resist layer includes a first fluorescent chemical marker and a second resist layer includes a second fluorescent chemical marker. Thus, different critical dimensions may be determined in situ for the various layers.

[0111] As described above, in one or more embodiments, a solubility modifier is diffused into a first 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 solubility modifier. At this point, the solubility modifier may diffuse a predetermined distance into the first resist to provide solubility-modified regions of the first resist. While 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 100. After the solubility modifier has diffused into the first resist, a second resist may be deposited on the substrate. The substrate may then be developed and etched as described with reference to method 100, except that the solubility-modified regions of the first resist are soluble in a particular developer.

[0112] In particular, any measurement can be sensitized according to the disclosed labeling techniques. Because the chemicals are removed in the development process, there is no effect on the device, but metrology is significantly improved. In the methods according to one or more embodiments, calibration curves for any controlled parameter, such as width or diameter, can be generated to achieve precise measurements. The methods herein can also have feed-forward calibration (to account for height variations).

[0113] For example, a series of different inputs for a range of otherwise identical areas can be created. This can be on a single substrate by exploiting site-to-site differences, or on a group of substrates. In optical applications, this can involve varying the dose. In thermal applications, this can involve varying the time and temperature. The changes can then be measured using a calibrated metrology system (SEM) on the resist and post-etch calibration. A lookup table can then be created, or a machine learning / artificial intelligence network can be created and used, or a calibration linearity can be created (e.g., 1 nm diameter per second of time). The generation of calibration curves for such purposes is conventional in the art, but is applied here for unconventional materials.

[0114] In one embodiment, the technique includes measuring weight change. The weight change may be measured only at the substrate level. The received substrate may be measured to determine the initial weight. Processing may then be performed, including coating with a solubility modifier, laminating with a second resist, diffusing the solubility modifier, and developing the second resist. After processing, the wafer may be measured again to determine the changed weight and / or weight difference.

[0115] In one or more embodiments, processing of the optical method involves measuring diameter / width variations by using calibration values ​​from the measurement system in question and calculating a correction curve for each target area. Optionally, smoothed calculations can be created, and any input from feedforward can be used. Feedforward will be understood to refer to incorporating measurements and correcting the process if the measurements deviate from predetermined values. Data measured and calculated according to the methods described herein can be used to correct hot plates, change average temperatures, or correct optical tools that use optical dose to correct for variations. In this manner, dye-based measurements described herein, such as method 100 of FIG. 1, can be used to optimize scanners and track tools.

[0116] In one or more embodiments, one or more layers of interest are deposited. The layer contains one or more dyes or chemical markers. Suitable layers can be polymer layers, organic layers, or resist layers. The layer can be measured before processing by weight and / or volume measurement by unit area. One or more processing processes can then be performed. The wafer and / or an area of ​​the wafer is then measured (post-processing). The spectra from the pre-processing and post-processing measurements can then be compared to find differences and calculate values. The change in volume can be converted to a change in diameter, given the known height and volume.

[0117] Based on the measurements, parameters for subsequent substrates can be adjusted based on the current data. This can be an adjustment to the inherent thermal activation or optical activation. In one or more embodiments, the temperature / time can be adjusted to increase the amount of diffusion into the second resist to increase the width of the removed area. For example, after calibration, if the known tradeoff is 1 sec / nm diffusion, and the measured amount of diffusion is off by 0.23 nm, the process diffusion time will change by 23 sec. In the case of an optical adjustment, for example, there will be an optically activated portion of the resist, but a dose to size calibration is performed. For example, if this is 1 mJ / cc per nanometer, a 0.23 nm change will require 1 mJ of dose to adjust and can be updated accordingly.

[0118] In one or more embodiments, a method includes measuring a single fluorescence intensity to measure a critical dimension, such as a volume, of a resist layer. The method includes depositing a first layer of a first photoresist containing a first chemical marker on a substrate, forming a first relief pattern from the first layer that defines an opening, and depositing a second photoresist on the substrate, the second photoresist filling the opening defined by the first relief pattern. The method then includes diffusing a solubility modifier a predetermined distance into the second photoresist to create a diffusion region, the solubility modifier being selected to render the second photoresist soluble in a particular developer, removing the diffusion region from the substrate to define the opening between the second photoresist and the first photoresist, and measuring the fluorescence intensity of the first layer from the first chemical marker after removing the diffusion region.

[0119] 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 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. depositing a first layer of a first resist on a substrate, the first resist including a first fluorescent chemical marker; measuring a first fluorescence intensity of the first layer from the first fluorescent chemical marker; forming a first relief pattern from the first layer of the first resist after measuring a first fluorescence intensity of the first layer; measuring a second fluorescence intensity of the first layer from a first chemical marker after forming the first relief pattern from the first layer of the first resist; depositing a solubility modifier onto the first relief pattern; depositing a second resist over the first relief pattern; diffusing the solubility-modifying agent into the second resist a predetermined distance in the range of 5 to 60 nm to provide a solubility-modified region of the second resist, the solubility-modified region of the second resist adjacent to the first relief pattern; developing the second resist such that the solubility-altered regions of the second resist are dissolved to provide openings between the first relief pattern and the second resist, exposing portions of the substrate; measuring a third fluorescence intensity of the first layer from the first chemical marker after developing the second resist; A microfabrication method comprising:

2. depositing a first layer of a first resist on a substrate, the first resist including a first fluorescent chemical marker; measuring a first fluorescence intensity of the first layer from the first fluorescent chemical marker; forming a first relief pattern from the first layer of the first resist after measuring the first fluorescence intensity of the first layer; measuring a second fluorescence intensity of the first layer from a first chemical marker after forming the first relief pattern from the first layer of the first resist; depositing a solubility modifier onto the first relief pattern; diffusing the solubility-modifying agent into the first resist a predetermined distance in the range of 5 to 60 nm to provide a solubility-modified region of the first resist; depositing a second resist over the first relief pattern; developing the first resist such that the solubility-altered regions of the first resist are dissolved to provide openings between the first relief pattern and the second resist, exposing portions of the substrate; measuring a third fluorescence intensity of the first layer from the first chemical marker after developing the first resist; A microfabrication method comprising:

3. adding a second fluorescent chemical marker to the second resist; measuring a fluorescence intensity of the second resist from the second fluorescent chemical marker before developing the second resist; measuring the fluorescence intensity of the second resist from the second fluorescent chemical marker after developing the second resist; The method of claim 1 or 2, further comprising:

4. 3. The method of claim 1, wherein absolute fluorescence intensity is measured for a given wavelength.

5. The method of claim 1 or 2, wherein the first chemical marker is a dye.

6. 6. The method of claim 5, wherein the dye is selected from the group consisting of a BODIPY dye, a cyanine 3 dye, a cyanine 5 dye, a cyanine 5.5 dye, a cyanine 7 dye, a fluorescein dye, a rhodamine dye, a coumarin dye, an 800CW dye, BP Fluor 680, BP Fluor 647, BP Fluor 594, BP Fluor 568, BP Fluor 546, BP Fluor 555, BP Fluor 350, BP Fluor 488, BP Fluor 430, BP Fluor 532, 4-(9H-carbazol-9-yl)benzoate, and 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)4H-pyran.

7. calculating a critical dimension of the solubility-altered region; identifying a critical dimension of said solubility-altered region that is outside a predetermined range of values; Alerting corresponding semiconductor manufacturing tools for process adjustments; The method of claim 1 or 2, further comprising:

8. calculating a volume measurement of the first resist; identifying a volume measurement of said solubility-altered region outside a range of predetermined values; adjusting a corresponding semiconductor manufacturing tool to provide subsequent volume measurements closer to the range of the predetermined value; The method of claim 1 or 2, further comprising:

9. calculating a volume measurement of the second resist; Identifying a volume measurement that is outside a predetermined range of values; adjusting a corresponding semiconductor manufacturing tool to provide subsequent volume measurements on subsequent wafers that are closer to or within the predetermined range of values; The method of claim 1 or 2, further comprising:

10. The method of claim 1 or 2, wherein forming the first relief pattern comprises forming a calibration design relief pattern for critical dimension calibration.

11. The method of claim 10 , wherein the critical dimension is a volume.

12. The method of claim 1 or 2, wherein the solubility-modifying agent comprises an acid generator.

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

14. 13. The method of claim 12, wherein the acid generator is selected from the group consisting of 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, triphenylsulfonium antiomate, and combinations thereof.

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

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

17. 16. The method of claim 15, 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.

18. 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.

19. 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.

20. 3. The method of claim 1 or 2, wherein the solubility modifier comprises a solvent selected from the group consisting of methyl isobutyl carbinol (MIBC), decane, isobutyl isobutyrate, isoamyl ether, and combinations thereof.

21. 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, acrylates, methacrylates, norbornene, and combinations thereof.

22. 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, acrylates, methacrylates, norbornene, and combinations thereof.

23. 3. The method of claim 1 or 2, wherein the diffusion of the solubility modifier is achieved by performing a bake.

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