Self-aligning build-up processing

Abstract

A micro-fabrication method includes providing a substrate having a pre-existing pattern, the pre-existing pattern including features formed in a base layer such that an upper surface of the substrate has uncovered features and the base layer is uncovered; depositing a selective binder onto the substrate, the selective binder including a solubility modifier; depositing a first resist onto the substrate, activating the solubility modifier such that a portion of the first resist is insoluble in a first developer; developing the first resist using the first developer to form a relief pattern including openings, the openings exposing the features of the pre-existing layer; and performing a selective growth process to grow a selective deposition material over the features and within the openings of the relief pattern to provide self-aligned selective deposition features.

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. After the first etch, processing can then continue with additional steps such as material deposition, etching, annealing, photolithography, and the various steps are repeated until a transistor or integrated circuit is fabricated.

[0002] There are multiple steps in semiconductor processing where critical features must be precisely aligned to underlying layers. Traditionally, the various processes can be aligned by aligning various mask layers, correcting their positioning, and then etching each layer in place. Summary of the Invention [Means for solving the problem]

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

[0004] In one aspect, embodiments disclosed herein relate to a microfabrication method that includes providing a substrate having a pre-existing pattern, the pre-existing pattern including features formed in a base layer such that an upper surface of the substrate has uncovered features and the base layer is uncovered; depositing a selective binder on the substrate, the selective binder including a solubility modifier; depositing a first resist on the substrate and activating the solubility modifier such that portions of the first resist are insoluble in a first developer; developing the first resist using the first developer to form a relief pattern including openings, the openings exposing the features of the pre-existing layer; and performing a selective growth process to grow a selective deposition material over the features and within the openings of the relief pattern to provide self-aligned selectively deposited features.

[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. DETAILED DESCRIPTION OF THE INVENTION

[0008] In device and node microfabrication, it is desirable for some features to be perfectly aligned using selective processing. A typical example is vias on metal. That is, vias are desired to be precisely positioned without extending through oxide. Vias are electrical connections between metal layers in a device. In selective deposition processes, it is desirable to grow preselected materials in a defined location, in a defined direction, and without defects. However, current directional growth techniques, such as selective atomic layer deposition, suffer from significant deficiencies. Furthermore, such techniques are often inadequate for more complex cases, such as selected growth areas extending to the sidewalls of spacers. Current self-aligned growth techniques generally tend to grow in all directions. Growing specific features is difficult with materials grown in all possible ways. Often, only very thin features can be grown as desired. Furthermore, self-aligned growth often has a high defect rate. Even small amounts of unintended deposition can cause problems in devices.

[0009] The present disclosure generally relates to a method for selective growth on a semiconductor 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 methods disclosed herein provide core self-aligned features that can be used to create fully or partially self-aligned features. In one or more embodiments, the methods combine selective feature placement and selective growth. The methods enable filling of various features and openings and may facilitate shallow trench isolation deposition.

[0010] The methods disclosed herein provide a self-aligned deposition method that inherently preserves areas not receiving deposition. Such methods may result in lower selectivity requirements for selective deposition. In one or more embodiments, partially aligned features or features without distinct openings may still be contactable, for example, as metal contacts. Furthermore, the methods may be used to coat and fill features with low spatial density, resulting in simpler integration throughout the majority of microfabrication processes.

[0011] The method of one or more embodiments relies on both chemical processes and diffusion characteristics to provide the unique ability to apply control functions to the input chemical reactions themselves and the process of measuring such chemical reactions.

[0012] As will be appreciated by those skilled in the art, the methods disclosed herein can be used to provide a variety of self-aligned features, such as self-aligned universal, selected self-aligned, and self-aligned features. As such, the specific embodiments described herein are not intended to limit the scope of the present disclosure. In one or more specific embodiments, a method for universal self-aligned vias is provided.

[0013] A universal self-alignment method 100 according to the present disclosure is shown in and will be discussed with reference to FIG. 1. Initially, in block 102, a pre-existing pattern including features in a base layer is provided on a substrate. In block 104, the substrate, or a portion thereof, is coated with a selective binder. The selective binder may include a solubility modifier. Then, in block 106, the substrate is coated with a first resist. In block 108, the solubility modifier may be activated to provide regions of the first resist that are soluble in a first developer. Then, in block 110, the first resist is developed to provide gaps in the first resist and expose features of the pre-existing pattern on the substrate. Finally, in block 112, selective growth on the features is performed. In some embodiments, after selective growth, the substrate is etched to remove any residual coating, such as the selective binder and the first resist.

[0014] Schematic illustrations of a coated substrate at various points during the above-described method are shown in Figures 2A-2E. 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 containing a pre-existing pattern. Figure 2B shows a substrate containing an overcoat comprising a selective binder. Figure 2C shows a substrate containing a selective binder overcoat overlaid with a first resist. Figure 2D shows the coated substrate after the first resist has been developed, thereby exposing the substrate features. Finally, Figure 2E shows a substrate containing the first resist and a selective growth layer over the substrate features. The method of Figure 1 and the coated substrates shown in Figures 2A-2E are discussed in more detail below.

[0015] In FIG. 1 , in block 102, a pre-existing pattern is provided on a substrate. FIG. 2A shows a substrate including a pre-existing pattern. In FIG. 2A , the pre-existing pattern includes features 202 formed in a base layer 201. The base layer can be any suitable substrate known in the art. In one or more embodiments, the features formed in the base layer are present in a large array. For example, on a square base layer, the features can be evenly spaced in a 4×4 array, a 5×5 array, a 6×6 array, etc. The shape and size of the array are not particularly limited and can be any shape and size suitable for use on a photolithography track.

[0016] The features may be made from any material commonly used in the art. In one or more embodiments, the features comprise metals, semi-metals, or other conductive structures. As used herein, the term metal includes alloys, stacks, and other combinations of metals. For example, metal interconnect lines may include barrier layers, stacks of various metals or alloys, and the like. Suitable metals and semi-metals from which the features may be composed include, but are not limited to, silicon, polysilicon, copper, cobalt, and tungsten. In one or more embodiments, the base layer is an interlayer dielectric. Suitable interlayer dielectrics may include oxides of silicon (e.g., silicon dioxide (SiO2)), doped oxides of silicon, fluorinated oxides of silicon, carbon-doped oxides of silicon, various low-k dielectric materials known in the art, and combinations thereof. The existing pattern may be a final feature or an intermediate feature in a patterning process. The substrate may be planarized so that the features of the existing pattern in the base layer are uncovered and accessible. In one or more embodiments, the substrate includes an etch stop layer or graphene coating over the metal lines.

[0017] Then, in block 104, a selective binding agent is coated onto the substrate or a portion thereof. Figure 2B shows a substrate including a pre-existing pattern coated with selective binding agent 203. The selective binding agent may be coated onto the substrate by any coating method known in the art. Suitable coating methods include, but are not limited to, vapor deposition, liquid deposition, vapor deposition, spin-on coating, and Langmuir-Blodgett monolayer coating.

[0018] The selective binding agent may preferentially adhere to one material of a pre-existing pattern. In one or more embodiments, the selective binding agent adheres to features of a pre-existing pattern of a substrate. In such embodiments, the selective binding agent may adhere to features of a pattern having a feature to first layer ratio of greater than 1:1. By way of example and not limitation, the selective binding agent may adhere to features of a pattern having a feature to first layer ratio ranging from about 2:1 to about 10:1 or greater.

[0019] In one or more embodiments, the selective binding agent is a chemical functional group that can be further functionalized. Exemplary selective binding agents include, but are not limited to, alcohols, silanols, amines, phosphines, phosphonic acids, and carboxylic acids. The specific selective binding agent coated on the existing pattern can depend on the specific chemistry used in other components of method 100. For example, various phosphonic acids and esters can selectively, or at least preferentially, react with bare or oxidized metal surfaces to form strongly bound metal phosphonates preferentially or even selectively on the surface of dielectric materials (e.g., oxides of silicon), which can then be used as selective binding agents for features rather than base layers. A specific example of a suitable phosphonic acid is octadecylphosphonic acid (ODPA). Such surface coatings generally tend to be stable in many organic solvents but can be removed using weakly acidic and weakly basic aqueous solutions. Phosphines (e.g., organophosphines) can also optionally be used. Other common acids, such as sulfonic acids, sulfinic acids, and carboxylic acids, can also optionally be used.

[0020] Another example of a reaction that is selective or at least preferential for metal materials over dielectric materials, organic polymeric materials, or other materials is various metal corrosion inhibitors, such as those used during chemical mechanical polishing to protect interconnect structures. Specific examples include benzotriazole, other triazole functional groups, other suitable heterocyclic groups (e.g., heterocyclic corrosion inhibitors), and other metal corrosion inhibitors known in the art. In addition to triazole groups, other functional groups can be used to provide the desired attraction or reactivity to metals. Various metal chelators are also potentially suitable. Various amines (e.g., organic amines) are also potentially suitable.

[0021] Yet another example of a selective or at least preferential reaction for metal materials over dielectric materials, organic polymeric materials, or other materials is various thiols. As another example, 1,2,4-triazole or similar aromatic heterocyclic compounds can be used to selectively react with metals over dielectrics and certain other materials. The selective binding agent can also contain functional groups capable of reacting with functional groups on a polymer to bind the polymer to a surface. Various other metal-poisoning compounds known in the art can also potentially be used. It should be understood that these are only a few illustrative examples, and that further examples will be apparent to those skilled in the art with the benefit of this disclosure. The selective binding agent can also include a polymer containing any of the aforementioned functional groups capable of selective binding, where the polymer has functional groups along the backbone or as terminal groups, forming a layer of polymer chains bound to the target material.

[0022] In one or more embodiments, the selective binder may include a solubility modifier. The composition of the solubility modifier may depend on the selective binder. As will be understood by those skilled in the art, any suitable solubility modifier may be included in the selective binder as long as the two materials do not react with each other. Generally, the solubility modifier may be any chemical substance that is activated by light or heat. For example, in some embodiments, the solubility modifier includes an acid or an acid generator. The acid, or in the case of TAG, the generated acid, should be sufficient to, upon heating, decompose the bonds of the acid-labile groups 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 20 wt % based on the total solids content of the trimming composition.

[0023] 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.

[0024] Exemplary fluorine-free aromatic acids include aromatic acids of the following general formula (I):

[0025] [ka]

[0026] 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.

[0027] An exemplary aromatic acid may be of the following general formula (II):

[0028] [ka]

[0029] [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]

[0030] Additional aromatic acids that may be included in the solubility modifier include those of the following general formula (III) or (IV):

[0031] [ka]

[0032] [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]

[0033] [ka]

[0034] [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]

[0035] Suitable aromatic acids may alternatively be of the following general formula (V):

[0036] [ka]

[0037] [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]

[0038] Further, exemplary aromatic acids can have the following general formula (VI):

[0039] [ka]

[0040] 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.

[0041] 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:

[0042] [ka]

[0043] [ka] [ka] [ka] [ka]

[0044] 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.

[0045] Preferably, the TAG is ionic in the reaction scheme for generating sulfonic acid as shown below.

[0046] [ka]

[0047] 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):

[0048] (BH) + (I)

[0049] 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.

[0050] 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.

[0051] Suitable exemplary nitrogen-containing cations (BH) + As for NH4 + , CF2HNH2 + , CF3CH2NH3+ , (CH3)3NH + , (C2H5)3NH + , (CH3)2(C2H5)NH + and the following:

[0052] [ka]

[0053] wherein Y is alkyl, preferably methyl or ethyl.

[0054] 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.

[0055] Alternatively, the solubility modifier may comprise a base or base generator. In such embodiments, suitable solubility modifiers include, but are not limited to, hydroxides, carboxylates, amines, imines, amides, and mixtures thereof. Specific examples of bases include ammonium carbonate, ammonium hydroxide, ammonium hydrogen phosphate, ammonium phosphate, tetramethylammonium carbonate, tetramethylammonium hydroxide, tetramethylammonium hydrogen phosphate, tetramethylammonium phosphate, tetraethylammonium carbonate, tetraethylammonium hydroxide, tetraethylammonium hydrogen phosphate, tetraethylammonium phosphate, and combinations thereof. Amines include aliphatic amines, cycloaliphatic amines, aromatic amines, and heterocyclic amines. Amines can be primary, secondary, or tertiary amines. Amines can be monoamines, diamines, or polyamines. Suitable amines can include C1-30 organic amines, imines, or amides, or can 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.

[0056] 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.

[0057] Alternatively, in one or more embodiments, the solubility modifier comprises a crosslinker. Suitable crosslinkers that can be used as solubility modifiers include, but are not limited to, crosslinkers used to cure bisepoxides such as bisphenol A diglycidyl ether, 2,5-bis[(2-oxiranylmethoxy)-methyl]-furan, 2,5-bis[(2-oxiranylmethoxy)methyl]-benzene, melamine, glycurils such as tetramethoxymethylglycoluril and tetrabutoxymethylglycoluril, benzoguanamine-based materials such as benzoguanamine, hydroxymethylbenzoguanamine, methylated hydroxymethylbenzoguanamine, ethylated hydroxymethylbenzoguanamine, and urea-based materials.

[0058] In one or more embodiments, the selective binding agent comprises a solvent. The solvent is typically selected from water, organic solvents, and mixtures thereof. In some embodiments, the solvent can comprise an organic-based solvent system comprising one or more organic solvents. The term "organic-based" means that the solvent system comprises greater than 50% by weight of organic solvent based on the total solvent in the solubility modifier composition, and more typically greater than 90%, greater than 95%, greater than 99%, or 100% by weight of organic solvent based on the total solvent in the solubility modifier composition. The solvent component is typically present in an amount of 90-99% by weight based on the solubility modifier composition.

[0059] Suitable organic solvents for the selective binder composition include, for example, alkyl esters such as alkyl propionates, such as n-butyl propionate, n-pentyl propionate, n-hexyl propionate, and n-heptyl propionate, and alkyl butyrates, such as n-butyl butyrate, isobutyl butyrate, and isobutyl isobutyrate; ketones, such as 2,5-dimethyl-4-hexanone and 2,6-dimethyl-4-heptanone; n-heptane, n-nonane, n-octane, n-decane, 2-methylheptane, 3-methylheptane, and the like. aliphatic hydrocarbons such as butane, 3,3-dimethylhexane and 2,3,4-trimethylpentane, and 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-heptanol, 1-octanol, 2-hexanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol, 3-octanol and 4-octanol; alcohols such as linear, branched or cyclic C4-C9 monohydric alcohols such as butanol; 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, as well 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, C5-C9 fluorinated diols such as 8-octanediol; ethers such as isopentyl ether and propylene glycol monomethyl ether; alkyl esters having a total carbon number of 4 to 10, for example, propylene glycol monomethyl ether acetate; 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; and polyethers such as dipropylene glycol monomethyl ether and tripropylene glycol monomethyl ether; and mixtures comprising one or more of these solvents.

[0060] In some embodiments, after coating the substrate with the selective binding agent, the substrate is pretreated. The substrate can be pretreated to ensure binding of the selective binding agent to the surface of the features. The pretreatment can be a soft bake performed at a temperature in the range of 50-150°C for about 30-90 seconds.

[0061] After the selective binding material is bonded to the features, excess material may be removed. Thus, in one or more embodiments, after applying and optionally pre-treating the selective binding agent to the substrate, the substrate is rinsed to remove unused material.

[0062] Then, in block 106 of the method 100, a first resist is deposited on the substrate. FIG. 2C shows a substrate 201 coated with a selective binder 203 and a first resist 204. The resist is typically a chemically amplified photosensitive composition comprising a polymer, a photoacid generator, and a solvent. In one or more embodiments, the first resist comprises a polymer. The polymer can be any standard polymer typically used in resist materials, particularly a polymer having acid-labile groups. The polymer can be a polymer made from monomers including aromatic vinyl monomers such as styrene and p-hydroxystyrene, acrylates, methacrylates, norbornene, and combinations thereof. 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 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 purpose. Acid labile groups include, for example, tertiary alkyl ester groups, secondary or tertiary aryl ester groups, secondary or tertiary ester groups having a combination of alkyl and aryl groups, tertiary alkoxy groups, acetal groups, or ketal groups. Acid labile groups are also commonly referred to in the art as "acid-decomposable groups," "acid-labile groups," "acid-labile protecting groups," "acid-leaving groups," and "acid-sensitive groups."

[0063] 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 C2-20 Alkenyl, branched C 3-20 Alkenyl, monocyclic or polycyclic C 3-20 Cycloalkenyl, monocyclic or polycyclic C 6-20 Aryl, or monocyclic or polycyclic C 2-20 Heteroaryl, preferably linear C 1-6 Alkyl, branched C 3-6 Alkyl, or monocyclic or polycyclic C 3-10 cycloalkyl, each of which is substituted or unsubstituted; and each R 1 optionally includes 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 C6-20 Aryl, or monocyclic or polycyclic C 2-20 Heteroaryl, preferably linear C 1-6 Alkyl, branched C 3-6 Alkyl, or monocyclic or polycyclic C 3-10 cycloalkyl, each of which is substituted or unsubstituted; R 3 optionally includes 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.

[0064] 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.

[0065] In some embodiments, the first resist has a composition similar to a positive tone developed (PTD) resist. In such embodiments, the first resist may comprise a polymer made from the monomers described above, in which one or more monomers containing reactive functional groups are protected. Thus, the PTD-like first resist may be organic soluble.

[0066] In other embodiments in which the solubility modifier is a crosslinker, the first resist is a negative resist. In such embodiments, the first resist may comprise a polymer made from the monomers described above, where any monomer containing a reactive functional group is unprotected. Suitable reactive functional groups include, but are not limited to, alcohols, carboxylic acids, amines, and epoxides. Exposure to a crosslinker causes crosslinking of the polymer, rendering it insoluble in a developer. The uncrosslinked areas can then be removed using an appropriate developer.

[0067] 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 one or more monomers containing reactive functional groups are protected. Thus, NTD first resists can be organic-soluble, but rather than developing the solubility-altered regions with a basic first resist developer, the solubility-altered regions remain, while the regions containing the protected functional groups are removed using a first resist developer containing an organic solvent. Suitable organic solvents that can be used as first resist developers include n-butyl acetate (NBA) and 2-heptanone. The tone of the resist (i.e., PTD vs. negative vs. NTD) can affect the final pattern placement.

[0068] In one or more embodiments, the first resist is deposited on the substrate to a thickness of about 300 Å to about 3000 Å.

[0069] At block 108 of method 100, the solubility modifier is activated. In embodiments where the solubility modifier is an acid, acid generator, base, or base generator, activating the solubility modifier includes diffusing the solubility modifier into the first resist to provide a solubility-altered region of the first resist. The solubility-altered region of the first resist can be determined by preferential adhesion of the selective binder. For example, a selective binder that preferentially adheres to features of a pre-existing pattern can provide a solubility-altered region of the first resist over the feature. In one or more embodiments, the solubility-altered region of the first resist extends vertically from the surface of the selective binder coated on the feature to the surface of the first resist. In one or more embodiments, the solubility-altered region extends in an oblique direction. When the solubility-altered region extends in an oblique direction, it may be desirable to prevent the features from bonding together. To achieve this, the thickness of the feature can be controlled to be sufficiently thin.

[0070] In one or more embodiments, diffusion of the solubility modifier into the first resist is achieved by baking. Baking can be performed on a hot plate or in an oven. The temperature and time of the bake can 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 baking can include a temperature ranging from about 50° C. to about 160° C. and a time ranging from about 30 seconds to about 90 seconds.

[0071] In embodiments where the solubility modifier is a cross-linking agent, activating the solubility modifier includes initiating polymerization of the cross-linking agent into the first resist. Activation of the cross-linking agent can provide cross-linked regions of the first resist. The cross-linked regions of the first resist can be determined by preferential adhesion of the selective binder. For example, if the selective binder preferentially adheres to features of a pre-existing pattern, such as in selective patterning self-alignment, the cross-linked regions of the first resist can overlie the features.

[0072] Then, in block 110 of method 100, the first resist is developed using a specific developer. The specific developer can be any developer commonly used in the art. The composition of the specific developer can depend on the tone and dissolution characteristics of the first resist. For example, if the first resist is a positive-tone developing resist, the specific developer can be a base such as tetramethylammonium hydroxide. On the other hand, if the first 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.

[0073] In one or more embodiments, the solubility-altered or crosslinked regions are insoluble in the first developer. Thus, after developing the first resist, the solubility-altered or crosslinked regions of the first resist may remain on the substrate. Alternatively, in one or more embodiments, the solubility-altered regions are soluble in the first developer. In such embodiments, after developing the first resist, the solubility-altered regions of the first resist are removed from the substrate. Such a pattern may be referred to as an anti-selective pattern, since resist features remain on the base layer that was not coated with the selective binder.

[0074] In one or more embodiments, the solubility-altered areas of the first resist are soluble in a first developer. In such embodiments, development of the first resist results in a pattern in the first resist that includes gaps that expose features of the existing pattern. In this manner, the selective binder is exposed and accessible for further coating. Figure 2D shows the coated substrate, with gaps 205 in the first resist 204 exposing features 202 of the existing pattern. In one or more embodiments, rinsing strips the remaining selective binder prior to metallization.

[0075] Finally, at block 112 of method 100, selective growth on the features of the existing pattern is performed. Any suitable selective growth technique known in the art may be used to provide the second set of features directly on the features of the existing pattern. Figure 2E shows a substrate including features 202, a first resist 204 offset from the features, and selectively grown material 206 over the features.

[0076] In one or more embodiments, the second set of features includes a selective growth material. Many different types of selective growth deposition materials known in the art are suitable for various embodiments disclosed herein. In some embodiments, selective metal-to-metal reactive deposition can be achieved in solution using techniques such as electroless metal deposition and / or electrochemical atomic layer deposition. Examples of metals suitable for such metal-to-metal reactive deposition include, but are not limited to, copper (Cu), nickel (Ni), cobalt (Co), iron (Fe), manganese (Mn), chromium (Cr), titanium (Ti), tantalum (Ta), ruthenium (Ru), palladium (Pd), and various alloys, stacks, or combinations thereof. Other metals that can be deposited by selective reaction using electroless metal deposition and / or electrochemical atomic layer deposition should also generally be suitable.

[0077] In some embodiments, selective metal-to-metal reactive deposition can be carried out using homoleptic metal diazabutadiene complexes [M{N(R)C(H)C(H)N(R')}2]. In this formula, M can represent a metal atom selected from nickel (Ni), cobalt (Co), iron (Fe), manganese (Mn), or chromium (Cr). The organic functional groups R and R' can represent any of a variety of substituted or unsubstituted alkyl or aryl functional groups. Examples of R and R' include, but are not limited to, substituted or unsubstituted 2-8 carbon alkyl groups, phenyl groups, and the like. Combinations of different complexes (e.g., those with different metal atoms) can also optionally be used. Metals (e.g., pure metals or alloys or stacks of multiple metals) can be deposited onto starting metals and / or onto metals deposited from these complexes using chemical vapor deposition (CVD) with or without co-reactants (e.g., hydrogen (H2), ammonia (NH3), hydrazine, etc.). Atomic layer deposition (ALD) can alternatively be used, as such deposition is generally selective compared to dielectric, semiconductor, and organic polymer materials.

[0078] In some embodiments, an applied voltage and / or the photoelectric effect may be used to promote metal deposition and / or increase the selectivity of metal deposition on a metal compared to another material (e.g., a dielectric). In some embodiments, a voltage bias may be applied between a wafer or other substrate and conductive hardware of a metal deposition apparatus, such as between a wafer chuck and a coil above a wafer on the wafer chuck. This voltage bias may be either direct current (DC) or alternating current (AC) (e.g., high-frequency AC). The applied voltage bias may tend to generate and reduce the energy required to eject or otherwise provide relatively more electrons (e.g., secondary electrons) from a metal (e.g., an interconnect line or a metal material formed on an interconnect line) than from another material (e.g., a dielectric), for example, due in part to the photoelectric effect. In some embodiments, a forward voltage bias may be applied to promote the acceleration of electrons away from the metal. When a DC voltage bias is used, electron ejection may be delayed after some electrons have been ejected from the metal and begin to have a net positive charge unless a conductive path to the metal exists. However, application of an AC voltage bias can generally help avoid this by backing up the metal with electrons between cycles. The electrons can be used to promote metal deposition and / or increase the selectivity of metal deposition on the metal relative to another material (e.g., a dielectric). The electrons can help provide energy to drive or promote selective metal deposition reactions, such as ALD or CVD deposition of metals, or other metal deposition processes that can be promoted by such generated electrons. In some embodiments, an ultraviolet light source can be used in conjunction with the voltage bias to help further generate photoelectrons near the metal. This can further help promote metal deposition and metal deposition selectivity.

[0079] In some embodiments, selective dielectric-to-dielectric reactive deposition can be achieved by liquid-phase techniques such as sol-gel processes. Selective dielectric-to-dielectric reactive deposition can also be achieved by CVD, ALD, MLD, or other gas-phase techniques. Examples of materials suitable for such dielectric-to-dielectric reactive deposition include, but are not limited to, oxides of silicon (e.g., silicon dioxide (SiO)), carbon-doped oxides of silicon, nitrides of silicon (e.g., silicon nitride (SiN)), carbides of silicon (e.g., silicon carbide (SiC)), carbonitrides of silicon (e.g., SiCN), oxides of aluminum (e.g., aluminum oxide (AlO)), oxides of titanium (e.g., titanium oxide (TiO)), oxides of zirconium (e.g., zirconium oxide (ZrO)), oxides of hafnium (e.g., hafnium oxide (HfO)), and combinations thereof, to name just a few illustrative examples. Other dielectric and low-k dielectric materials known in the art are also potentially suitable. Carbosiloxane materials may also optionally be used. Various examples of reactions are known in the art that deposit such materials selectively, or at least preferentially, compared to metals using techniques such as sol-gel, ALD, CVD, and MLD.

[0080] In some embodiments, one or more of carbon nanotubes, graphene, and graphite can be grown or formed on a metal surface material. The metal surface material can represent a catalytic metal surface material that is catalytic to the growth of carbon nanotubes, graphene, or graphite. The catalytic metal surface material can be heated and exposed to a suitable hydrocarbon and any other co-reactants using techniques known in the art. One example of a suitable catalytic surface and set of reactants is a cobalt surface exposed to carbon monoxide and hydrogen. The voltage bias approach described above can also potentially be used to help promote such reactions.

[0081] In some embodiments, a passivating material or layer may optionally be applied or formed on one of various surface materials to help increase the selectivity or preference of a reaction relative to another surface material. The use of such a passivating material generally serves to increase the number of possible selective / preferential reactions available for forming a layer. Nevertheless, reactions that are not necessarily selective / preferential for one of the surface materials over the others may be selective for one of the surface materials compared to the passivating material. As an example, a passivating material may be applied to a first surface material rather than a second surface material to increase the selectivity / preference of a given deposition reaction for the second surface material compared to the passivating material. Most passivating materials that are operable to selectively form on one of the materials and to increase the selectivity / preference of the reaction should generally be suitable. Such passivating agents may be applied in the vapor or liquid phase. Such passivating agents may be applied one or more times during the selective deposition process. After a layer is formed through the selective / preferential reaction, the passivating material may be removed. For example, the passivating material may be removed by thermal, photolytic, chemical, or electrochemical treatment. In some embodiments, a separate passivating material may optionally be applied to other surface materials, although this is not required. Again, the use of such a passivating material, although optional, may serve to increase the number of possible selective or at least preferential chemical reactions that may be used to form the various layers referred to herein.

[0082] In one or more embodiments, after selective growth is performed on the features of the existing pattern, the substrate may be etched to remove residual organic materials, including selective binders, solubility modifiers, and resist. A dielectric isolation material may then be deposited to fill the new features formed by the selective growth process. Examples of materials suitable for such dielectric deposition include, but are not limited to, oxides of silicon (e.g., silicon dioxide (SiO)), carbon-doped oxides of silicon, nitrides of silicon (e.g., silicon nitride (SiN)), carbides of silicon (e.g., silicon carbide (SiC)), silicon carbonitrides (e.g., SiCN), oxides of aluminum (e.g., aluminum oxide (AlO)), oxides of titanium (e.g., titanium oxide (TiO)), oxides of zirconium (e.g., zirconium oxide (ZrO)), oxides of hafnium (e.g., hafnium oxide (HfO)), and combinations thereof, to name just a few illustrative examples. A chemical-mechanical polishing process may then be used to planarize the surface. For example, if silicon dioxide is deposited and such deposition provides an overburden, the overburden can be removed by chemical mechanical polishing.

[0083] Thus, the method 100 can provide self-aligned vias or metal contacts with a growth direction that is approximately vertical due to the restriction applied by the peripheral first resist.

[0084] In an alternative embodiment, the feature is coated with a first selective binder containing a first solubility modifier, and the base layer is coated with a second selective binder containing a second solubility modifier. In some embodiments, the first solubility modifier comprises an acid or acid generator, and the second solubility modifier comprises a base or base generator. Resist is then deposited on the substrate, and the solubility modifiers are activated simultaneously. The first solubility modifier diffuses from above the feature, and the second solubility modifier diffuses from above the base layer. At the interface of the diffusion front, the solubility modifiers interact with each other to prevent modification of the resist solubility in lateral areas outside of the vertical surface perpendicular to the substrate and located at the interface between the feature and the exposed base layer. This helps to suppress solubility modification in areas of the resist above the feature, thereby limiting lateral growth of the opening and creating a nearly straight edge rather than a sloped profile.

[0085] In one or more embodiments, the method includes a photolithography process. Photolithography can be used to select specific features, portions of features, or other regions. For example, selective placement and growth can be achieved using a directional growth process, as in method 100 described above. A first resist can then be exposed to form a patterned array that exposes the desired areas and activates the solubility modifier in those areas. A thermal treatment then causes the solubility modifier to diffuse through the resist layer, promoting the solubility modification reaction. A solubility modifier (e.g., acid) makes the resist soluble and removes portions thereof. Selective growth on the metal / substrate can then be performed. The selective growth can be preceded by an etching process to remove residual coatings of selective binder and / or solubility modifier from the top of uncovered features.

[0086] 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. providing a substrate having a pre-existing pattern, the pre-existing pattern including features formed in a first layer such that a top surface of the substrate has uncovered features and the first layer is uncovered; depositing a selective binding agent onto the substrate, the selective binding agent chemically adhering more readily to a surface of the feature than to a surface of the first layer, the selective binding agent including a solubility modifier; depositing a first resist on the substrate; activating the solubility modifier so that a portion of the first resist becomes insoluble in a first developer; developing the first resist using the first developer to form a relief pattern including openings, the openings exposing the features of the first layer; performing a selective growth process to grow a selective deposition material over the features and within the openings of the relief pattern to provide self-aligned selective deposition features; A microfabrication method comprising:

2. The method of claim 1 , wherein the features formed in the first layer form a large array.

3. 3. The method of claim 1 or 2, wherein the selective binding agent comprises a phosphonic acid, a phosphonate ester, a phosphine, a sulfonic acid, a sulfinic acid, a carboxylic acid, a triazole, a thiol, or a combination thereof.

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

5. The method of claim 4 wherein the acid generator is fluorine-free.

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

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

8. 8. The method of claim 7, wherein the acid is fluorine-free.

9. 8. The method of claim 7, 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.

10. 3. The method of claim 1, further comprising pretreating the substrate before depositing the first resist on the substrate.

11. The method of claim 1 or 2, wherein the features comprise a metal or semi-metal selected from the group consisting of silicon, polysilicon, copper, cobalt, tungsten, and combinations thereof.

12. The method of claim 1 or 2, wherein the first layer comprises a dielectric material.

13. receiving a substrate having features formed in a first layer such that an upper surface of the substrate has the uncovered features and the uncovered first layer; depositing a first solubility modifier onto the substrate, the first solubility modifier being selected to adhere to uncovered surfaces of the feature without adhering to uncovered surfaces of the first layer; depositing a second solubility modifier onto the substrate, the second solubility modifier being selected to adhere to the uncovered surface of the first layer without adhering to the uncovered surface of the feature; depositing a first photoresist on the substrate; activating the first solubility-modifying agent sufficiently so that regions of the first photoresist over the features become soluble in a particular developer; activating the second solubility modifier such that the second solubility modifier increases the insolubility of the first photoresist on the first layer; developing the first photoresist to produce a relief pattern defining openings exposing the features; performing a selective growth process to grow a selective deposition material over the features and within the defined openings of the relief pattern to produce self-aligned selective deposition features; A microfabrication method comprising:

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