Methods, structures, and systems for lithographic patterning

Abstract

To provide methods, structures, and systems for lithographic patterning.SOLUTION: Methods, related structures, and related systems are provided for lithography, particularly extreme ultraviolet (EUV) lithography. Presently disclosed methods can comprise forming a carbon underlayer having a high sp3 carbon content. Presently disclosed methods can comprise forming a carbon underlayer by a deposition process that comprises continually generating a plasma and providing a precursor in a sequence of discrete pulses.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure is in the field of integrated circuit manufacturing, and more particularly in the field of lithography. [Background technology]

[0002] Compared with previous ultraviolet (UV) lithography methods, the resolution of EUV lithography is improved through a reduction in wavelength, which also increases photon energy and therefore significantly increases energy consumption. To reduce dose, either the photon flux or exposure time must be reduced, both of which reduce the total number of photons striking the lithography resist to a very low amount. Furthermore, high-energy EUV photons are more difficult to absorb by most materials, exacerbating the problem of low photon counts. With such a low number of photons absorbed by the resist, it is difficult to obtain good-quality lithography structures, especially when small feature sizes are pursued, due to the photon shot noise effect. Therefore, the key to realistically reducing dose is to increase the useful effect of the limited photons received.

[0003] EUV resists are continually being improved to increase the material absorption of each photon and increase the number of electrons generated per photon. Absorption is often improved by inserting EUV-absorbing materials into the lithographic structure that generate excited electrons, and the number of secondary electrons is increased by creating an electron cascade, generating many lower-energy electrons to initiate chemical changes in the resist. Current resists are optimized to maximize these effects and absorb most photons. However, there remains a need for further dose reduction.

[0004] Amorphous carbon layers are used in lithography, such as EUV lithography. They are applied using high-throughput methods with high deposition rates, such as spin coating, flowable deposition, and / or plasma-enhanced chemical vapor deposition. These methods result in hard masks that do not offer dose reduction benefits for EUV lithography. "Dose" refers to the photon energy required to fully develop the resist. "Dose reduction" refers to the reduction in dose required for a particular lithography solution compared to a reference. Summary of the Invention [Means for solving the problem]

[0005] Described herein is a system constructed and arranged to form an underlayer for lithographic patterning, the system comprising: a substrate support constructed and arranged to support a substrate; a substrate transfer robot constructed and arranged to position the substrate on the substrate support; a reaction chamber constructed and arranged so that the substrate support supports the substrate; a plasma gas conduit constructed and arranged to provide plasma gas from a plasma gas source comprising a plasma gas to the reaction chamber; a precursor conduit constructed and arranged to provide a precursor from a precursor source comprising a precursor to the reaction chamber; a plasma generator constructed and arranged to generate a plasma in the reaction chamber; and a process controller constructed and arranged to cause the system to perform a deposition process, the deposition process including providing plasma gas to the reaction chamber; sequentially generating a plasma in the reaction chamber by the plasma generator and the plasma gas; and providing precursors to the reaction chamber in a series of discrete precursor pulses while sequentially generating the plasma in the reaction chamber;

[0006] In some embodiments, the plasma generator comprises an inductively coupled plasma source.

[0007] In some embodiments, the plasma generator comprises a capacitive plasma source.

[0008] A method of forming an underlayer for lithographic patterning is further described, the method comprising: providing a substrate to a reaction chamber; performing a deposition process including providing a plasma gas to the reaction chamber; continuously generating a plasma in the reaction chamber with the plasma gas; and providing precursors to the reaction chamber in a series of individual precursor pulses while continuously generating the plasma in the reaction chamber; wherein the underlayer comprises amorphous carbon.

[0009] In some embodiments, the precursor comprises an organic compound.

[0010] In some embodiments, the organic compound comprises a hydrocarbon.

[0011] In some embodiments, the precursor comprises an aromatic compound.

[0012] In some embodiments, the aromatic compound is selected from the list consisting of benzene, alkylbenzene, toluene, ethylbenzene, xylene, durene, aniline, phenol, benzoic acid, biphenyl, mesitylene, styrene, toluidine, toluic acid, cresol, and naphthalene.

[0013] In some embodiments, the aromatic compound comprises 1,2,4-trimethylbenzene.

[0014] In some embodiments, the precursor comprises an alkane.

[0015] In some embodiments, the precursor comprises octane.

[0016] In some embodiments, the plasma gas comprises a noble gas.

[0017] In some embodiments, the plasma gas further comprises hydrogen.

[0018] In some embodiments, the underlayer consists essentially of amorphous carbon.

[0019] In some embodiments, the deposition process results in an initial underlayer having an initial sp3 carbon content, and following the deposition process, the substrate is subjected to a treatment step, which results in a treated underlayer having a treated sp3 carbon content, the treated sp3 carbon content being greater than the initial sp3 carbon content.

[0020] In some embodiments, the treatment process comprises a plasma treatment process comprising generating a treatment plasma and exposing the substrate to one or more active treatment species generated in the treatment plasma.

[0021] In some embodiments, the treatment plasma comprises one or more of an argon plasma and an oxygen plasma.

[0022] In some embodiments, the series of individual precursor pulses includes multiple micro precursor pulses.

[0023] Further described herein is a method of forming an underlayer for lithographic patterning, the method comprising: providing a substrate to a reaction chamber; and performing a deposition process including providing a plasma gas, sequentially generating a plasma with the plasma gas to generate activated species, sequentially exposing the substrate to the activated species, and providing precursors to the reaction chamber in a series of individual precursor pulses while sequentially generating the plasma; wherein the underlayer comprises amorphous carbon.

[0024] In some embodiments, the plasma gas is provided to a remote plasma unit, which is operably connected to the reaction chamber via an activated species duct to continuously provide activated species to the reaction chamber.

[0025] This Summary is provided to introduce a selection of concepts in a simplified form that are described in more detail below in the Detailed Description of Example Embodiments of this Disclosure. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 1 illustrates an embodiment of a system 100. [Figure 2] 2 illustrates an embodiment of the methods 200, 300. FIG. [Figure 3] 2 illustrates an embodiment of the methods 200, 300. FIG. [Figure 4] 4 illustrates an embodiment of a structure 400. FIG. [Figure 5] 1 illustrates an embodiment of a system 500, 600. FIG. [Figure 6] 1 illustrates an embodiment of a system 500, 600. FIG. [Figure 7] 1 illustrates an embodiment of a deposition process. [Figure 8] 8A and 8B illustrate embodiments of systems 800 and 900. [Figure 9] 8A and 8B illustrate embodiments of systems 800 and 900. DETAILED DESCRIPTION OF THE INVENTION

[0027] It will be appreciated that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of the illustrated embodiments of the present disclosure. DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0028] While certain specific embodiments and examples are disclosed below, it will be understood by those skilled in the art that the invention extends beyond the specifically disclosed embodiments and / or uses of the invention, and obvious modifications and equivalents thereof. It is therefore not intended that the scope of the disclosed invention should be limited by the specific disclosed embodiments described below.

[0029] As used herein, the term "substrate" may refer to any underlying material, including any underlying material that may be modified or upon which a device, circuit, or film may be formed. A "substrate" may be continuous or discontinuous, rigid or flexible, solid or porous, and combinations thereof. The substrate may be in any form, such as a powder, plate, or workpiece. A substrate in the form of a plate may include wafers of various shapes and sizes. The substrate may be made from semiconductor materials, including, for example, silicon, silicon germanium, silicon oxide, gallium arsenide, gallium nitride, and silicon carbide. In some embodiments, the substrate may have OH termination. The OH termination may occur naturally, for example, through atmospheric oxidation, or the OH termination may be intentionally provided, for example, by subjecting the substrate to plasma treatment.

[0030] For example, the substrate in powder form may have applications in pharmaceutical manufacturing. The porous substrate may comprise a polymer. Examples of workpieces may include medical devices (e.g., stents and syringes), jewelry, tooling devices, components for battery manufacturing (e.g., anodes, cathodes, or separators), or components for photovoltaic cells, etc.

[0031] The continuous substrate may extend beyond the boundaries of the process chamber in which the deposition process occurs. In some processes, the continuous substrate may move through the process chamber, allowing the process to continue until the end of the substrate is reached. The continuous substrate may be supplied from a continuous substrate supply system to enable the production and output of the continuous substrate in any suitable form.

[0032] Non-limiting examples of continuous substrates may include sheets, nonwoven films, rolls, foils, webs, flexible materials, bundles of continuous filaments or fibers (e.g., ceramic or polymeric fibers). Continuous substrates may also include carriers or sheets onto which discontinuous substrates are placed.

[0033] The examples presented herein are not meant to be actual representations of any particular materials, structures, or devices, but are merely idealized representations used to describe embodiments of the present disclosure.

[0034] The specific implementations shown and described are illustrative of the disclosed method and its best mode and are not intended to otherwise limit the scope of aspects and implementations in any way. Indeed, for the sake of brevity, conventional manufacturing, association, preparation, and other functional aspects of the system may not be described in detail. Moreover, connecting lines shown in the various figures are intended to represent example functional relationships and / or physical couplings between the various elements. Many alternative or additional functional relationships or physical connections may be present in an actual system and / or may not be present in some embodiments.

[0035] Of course, tBu represents tert-butyl and Me represents methyl.

[0036] It should be understood that the configurations and / or approaches described herein are exemplary in nature, and that these specific embodiments or examples are not to be construed in a limiting sense, as numerous variations are possible. The specific routines or methods described herein may represent one or more of any number of processing strategies. As such, various illustrated operations may be performed in the order illustrated, in other orders, or omitted in some cases.

[0037] The subject matter of the present disclosure includes all novel and non-obvious combinations and subcombinations of the various processes, systems, and configurations, and other features, functions, operations and / or properties disclosed herein, as well as any and all equivalents thereof.

[0038] Referring to FIG. 1 described herein, one embodiment of a system 100 is shown. The system 100 can be constructed and arranged to form an underlayer for lithographic patterning. The underlayer can include amorphous carbon. The system 100 includes a reaction chamber 110. The reaction chamber 110 includes a substrate support 120. The substrate support 120 is constructed and arranged to support a substrate 130. The system 100 further includes a substrate transfer robot 140. The substrate transfer robot 140 is constructed and arranged to position the substrate 130 on the substrate support 120. The system 100 further includes a plasma gas conduit 150. The plasma gas conduit 150 is constructed and arranged to provide plasma gas 152 from a plasma gas source 151 containing plasma gas 152 to the reaction chamber 110. The plasma gas conduit 150 can be configured with a plasma gas conduit valve 153 constructed and arranged to close and open the plasma gas conduit 150. The system 100 further includes a precursor conduit 160. The precursor conduit 160 is constructed and arranged to provide the precursor 162 from a precursor source 161 containing the precursor 162 to the reaction chamber 110. The precursor conduit 160 may be arranged with a precursor conduit valve 163 constructed and arranged to close and open the precursor conduit 160. The system 100 further includes a plasma generator 170. The plasma generator 170 is constructed and arranged to generate a plasma within the reaction chamber 110. The system 100 further includes a process controller 180. The process controller 180 is constructed and arranged to cause the system to perform a deposition process.

[0039] An embodiment of such a deposition process 200 will be described with reference to Figure 2. The deposition process 200 includes providing 210 a plasma gas to the reaction chamber 110. Preferably, the plasma gas can be provided continuously to the reaction chamber 110. The deposition process 200 further includes continuously generating 220 a plasma in the reaction chamber 110 by a plasma generator 170 and plasma gas 152. The deposition process 200 further includes providing 230 precursors to the reaction chamber in a series of individual precursor pulses while continuously generating the plasma in the reaction chamber.

[0040] Further described herein are embodiments of methods for forming an underlayer for lithographic patterning. The method includes providing a substrate to a reaction chamber. The method further includes providing a plasma gas. The method further includes continuously generating a plasma with the plasma gas to generate activated species. The method further includes continuously exposing the substrate to the activated species. The method further includes continuously generating the plasma while providing precursors to the reaction chamber in a series of individual precursor pulses. In some embodiments, the underlayer includes amorphous carbon. For example, such methods can be performed in or by a system as described herein.

[0041] Advantageously, methods according to embodiments of the present disclosure can provide dose reduction for EUV lithography. In addition, methods according to embodiments of the present disclosure can provide carbon underlayers having more sp3 carbon than sp2 carbon. In some embodiments, methods according to embodiments of the present disclosure can advantageously provide growth rates of less than 1 nm / sec.

[0042] In some embodiments, the plasma gas is provided to a remote plasma unit that is operably connected to the reaction chamber via an activated species duct to continuously provide activated species to the reaction chamber.

[0043] In some embodiments, the precursor pulse from the series of individual precursor pulses comprises multiple micro precursor pulses, in other words, the precursor pulse can comprise a series of micro precursor pulses in which precursor is provided, separated by a moment during which the flow of precursor stops.

[0044] Advantageously, systems and methods according to embodiments of the present disclosure can provide dose reduction, i.e., they enable the formation of photolithographic patterns with fewer photons compared to a baseline. For example, during EUV exposure, metal centers may absorb EUV radiation. Therefore, photoelectrons may be generated. Cascading photoelectrons may generate primary and secondary electrons. The secondary electrons may break radiation-sensitive ligands away from the metal centers. An underlayer formed according to embodiments of the present disclosure may increase secondary electron flow into the resist. When the exposed resist is exposed to air, the broken ligands may react with at least one of HO and O in the air to form hydroxyl groups. Then, when the exposed resist is subjected to a thermal treatment, for example, using a post-bake, the hydroxyl groups may condense to form metal oxides. The unexposed resist may then be removed using a developer to form the pattern.

[0045] It should be noted that the subject matter of this disclosure is not bound to any particular theory or mode of operation, and that dose reduction can occur through a variety of mechanisms. For example, for extreme ultraviolet (EUV) lithography, dose reduction can occur through effects during exposure, or during post-bake, or during resist development, or through a combination of various effects.

[0046] In some embodiments, the plasma generator 170 comprises an inductively coupled plasma source. In such embodiments, the plasma may comprise an inductively coupled plasma (ICP).

[0047] In some embodiments, the plasma generator 170 comprises a capacitive plasma source. In such embodiments, the plasma may comprise a capacitively coupled plasma (CCP).

[0048] 3, an embodiment of a method 300 is described that includes providing 310 a substrate to a reaction chamber. The method further includes performing a deposition process 320. The deposition process 320 includes providing 321 a plasma gas to the reaction chamber. The deposition process 320 further includes generating 322 a plasma in the reaction chamber with the plasma gas. The deposition process 320 further includes providing 323 a precursor to the reaction chamber in a series of individual precursor pulses while continuously generating the plasma in the reaction chamber. Of course, the underlayer includes amorphous carbon.

[0049] In some embodiments, the underlayer may be treated 330 after it is formed. Indeed, the underlayer may be subjected to a treatment step, such as an anneal, e.g., a forming gas anneal, at a temperature of at least 75°C and up to 700°C, or at least 300°C and up to 600°C, or at least 200°C and up to 500°C. The treatment step may advantageously increase the sp3 content of the underlayer. Thus, in some embodiments, the deposition process results in an initial underlayer having an initial sp3 carbon content. Following the deposition process, the substrate is subjected to a treatment step. The treatment step results in a treated underlayer. The treated underlayer has a treated sp3 carbon content. The treated sp3 carbon content is greater than the initial sp3 carbon content.

[0050] In some embodiments, the annealing occurs immediately after deposition without any intervening steps. In some embodiments, the annealing occurs after one or more intervening steps have been performed. The series of intervening steps can include exposing the substrate to EUV light through a mask and subjecting the substrate to a post-bake.

[0051] In some embodiments, the treatment can include exposing the substrate to a treatment precursor. In some embodiments, the treatment can include exposing the substrate to a plasma employing a plasma gas, i.e., a treatment plasma gas including the treatment precursor. In some embodiments, exposing the substrate to the plasma and at least one of the treatment precursors can occur at the same temperature as the temperature at which the underlayer is deposited. Alternatively, exposing the substrate to the plasma and at least one of the treatment precursors can occur at different temperatures. For example, exposing the substrate to the plasma and at least one of the treatment precursors can occur at a temperature of at least 75°C and at most 700°C, or at least 300°C and at most 600°C, or at least 200°C and at most 500°C.

[0052] In some embodiments, the deposition process results in an initial underlayer having an initial sp3 carbon content, and the deposition process can be followed by subjecting the substrate to a treatment step. The treatment step can result in a treated underlayer having a treated sp3 carbon content. The treated sp3 carbon content can be greater than the initial sp3 carbon content.

[0053] In some embodiments, the treating step comprises a plasma treating step that includes generating a treating plasma, and the treating step can include exposing the substrate to one or more active treating species generated in the treating plasma.

[0054] In some embodiments, the treatment plasma comprises one or more of an argon plasma and an oxygen plasma.

[0055] In some embodiments, the treatment step can be performed in situ. In some embodiments, the treatment step can be performed in the same reaction chamber as the deposition process. In some embodiments, the treatment step can be performed in a different reaction chamber, a treatment reaction chamber, included in a cluster system that also includes a deposition reaction chamber in which the deposition process is performed. Thus, the deposition process and the treatment step can be performed sequentially without any intervening vacuum break. For example, the substrate is not exposed to pressures greater than 100 Torr, or 10 Torr, or 1 Torr during transfer between the deposition reaction chamber and the treatment reaction chamber.

[0056] Advantageously, processing steps such as those disclosed herein can be employed to tailor the adhesion of the resist to the underlying layer, thereby allowing for easy removal of the resist without causing pattern collapse.

[0057] In some embodiments, the treatment step includes a plasma treatment step that includes generating a treatment plasma employing a treatment plasma gas. The plasma treatment step can include exposing the substrate to one or more active treatment species. Advantageously, the treatment can improve, i.e., reduce critical dimensions, i.e., allow smaller features to be printed without defects, i.e., pattern collapse. In some embodiments, the treatment plasma gas includes a noble gas and, optionally, hydrogen. Additionally or alternatively, the noble gas can include one or more of an oxygen reactant, a nitrogen reactant, a boron reactant, and a carbon reactant. Suitable oxygen reactants can be selected from O2, O3, HO, HO, NO2, NO2, and NO3. Suitable nitrogen reactants can be selected from N2, NH3, and NH2. Suitable carbon reactants can include hydrocarbons, such as alkanes, such as CH4, formic acid, and isopropanol. Suitable boron reactants can include boron hydrides such as B2H6 and B3H6N3, and suitable sulfur reactants can include hydrogen sulfide (HS), carbon disulfide (CS2), and sulfur (S). Suitable phosphorus reactants can include phosphine (PH3) and white phosphorus. In some embodiments, the treatment plasma gas includes a noble gas and a SiOC precursor. In some embodiments, the precursor includes Si and C. In some embodiments, the precursor includes a Si-C bond. In some embodiments, the precursor includes an alkyl, alkenyl, alkynyl, or aryl group bonded to silicon. In some embodiments, the precursor includes an alkylamino group bonded to Si. In some embodiments, the alkylamino is selected from -NMe2, -NEt2, -NEtMe, -NHtBu, -N(iPr)2, -N(sBu)2, -N(SiMe3)2, and -N(SiEt3)2. In some embodiments, the precursor includes an alkoxy group bonded to Si. In some embodiments, the alkoxy group is selected from -OMe, -OEt, -OiPr, -OtBu, -OsBu, -OtPn, -OSiMe3, or -OSiEt3.In some embodiments, the SiOC precursor is selected from the list consisting of dimethyldimethoxysilane, tetramethyldimethoxydisiloxane, (3-methoxypropyl)trimethoxysilane, bis(diethylamino)silane, hexamethyldisilazane, and dimethyltrimethylsilylamine. In some embodiments, the SiOC precursor is selected from the list consisting of: SiH(NMe2)3, Si(NMe2)4, Si(NEtMe)4, SiCl(NMe2)3, SiH2(NEt2)2, SiH2(NHtBu)2, SiH3(N(iPr)2), SiH3(N(sBu)2), Si2(NHEt)6, Si(OEt)4, SiMe3(NMe2), SiMe2(NMe2), SiH2(NEtMe)2.

[0058] For example, the treatment plasma gas can include O. For example, the treatment plasma gas can include HO, e.g., a plasma gas consisting essentially of Ar and HO. In some embodiments, the treatment plasma gas includes O and Ar. In some embodiments, the treatment plasma gas consists essentially of O and Ar.

[0059] In some embodiments, the treatment includes converting some or all of the sp2 carbon in the underlayer according to embodiments of the present disclosure to sp3 carbon. Such conversion can be achieved by introducing one or more treatment precursors into the deposition process or as a post-deposition exposure step. For example, during deposition, the treatment precursor can be provided together with the precursor, in alternating pulses, or continuously. In some embodiments, the deposition and treatment steps are performed cyclically.

[0060] In some embodiments, the treatment precursor comprises an alkylating agent, such as a strong alkylating agent.

[0061] In some embodiments, alkylating agents can include diiodo-substituted hydrocarbons, such as diiodoalkanes, such as diiodomethane, and 1,2-diiodoethane.

[0062] In some embodiments, the alkylating agent comprises a sulfonate such as methyl fluorosulfonate, methyl methanesulfonate, and methyl trifluoromethanesulfonate.

[0063] In some embodiments, the alkylating agent comprises a sulfate, such as an alkyl sulfate, such as dimethyl sulfate.

[0064] In some embodiments, the alkylating agent comprises a dihydrocarbyl carbonate, such as a dialkyl carbonate, such as dimethyl carbonate.

[0065] In some embodiments, the treatment precursor comprises a chemical capable of performing a transfer hydrogenation reaction.

[0066] For example, in some embodiments, the treatment precursor can include an organic acid, such as formic acid.

[0067] In some embodiments, the treatment precursor comprises an alcohol, such as an alkyl alcohol, such as isopropanol.

[0068] In some embodiments, the treatment precursor comprises a cyclic hydrocarbon.

[0069] In some embodiments, the treatment precursor comprises a cyclic diene, such as a substituted or unsubstituted hexadiene, such as a compound selected from the list consisting of 1,3-cyclohexadiene, 1,4-cyclohexadiene, and 1-methyl-1,4-cyclohexadiene.

[0070] In some embodiments, the treatment precursor comprises one or more aromatic rings. For example, the treatment precursor can comprise one or more of 9,10-dihydroanthracene or hydroquinone.

[0071] In some embodiments, the treatment precursor can include one or more of hydrazine and hydrazine derivatives. For example, the treatment precursor can be selected from the list consisting of hydrazine, dimethylhydrazine, and tert-butylhydrazine.

[0072] In some embodiments, the treatment precursor can include a dihydrocarbylhydroxylamine, such as a dialkylhydroxylamine, such as diethylhydroxylamine.

[0073] In some embodiments, the treatment precursor comprises a diimide.

[0074] In some embodiments, the treatment includes annealing the substrate. In some embodiments, the substrate is thermally annealed for a period of about 1 minute to about 15 minutes. In some embodiments, the substrate is thermally annealed at a temperature of about 200°C to about 500°C. In some embodiments, the thermal annealing step includes two or more steps in which the substrate is thermally annealed at a first temperature for a first period of time, and then at a second temperature for a second period of time.

[0075] In some embodiments, the treatment includes exposing the underlayer to reactive species generated from a plasma, specifically a treatment plasma. For example, reactive species generated from a plasma containing hydrogen and argon can be used. The underlayer may be exposed to the plasma for about 0.1 seconds to about 1 minute, such as about 1 second to about 30 seconds, or about 5 seconds to about 30 seconds, or about 1 second to about 15 seconds, or about 3 seconds to about 20 seconds, e.g., about 5 seconds, about 10 seconds, about 20 seconds, or about 30 seconds. Plasma powers of at least about 20 W, or at least about 50 W, about 20 W to about 100 W, such as 30 W, 50 W, or 70 W, may be used. Suitable plasma powers and durations of plasma exposure may be determined experimentally.

[0076] In some embodiments, the treating step comprises exposing the underlayer to electromagnetic radiation, such as one or more of microwaves, infrared radiation, visible light, ultraviolet light, or extreme ultraviolet light, and x-rays.

[0077] In some embodiments, forming the underlayer includes performing multiple supercycles, where one from the multiple supercycles includes a deposition process and a treatment step. The deposition process and the treatment step can be performed in the same reaction chamber or in different reaction chambers included in the same vacuum system. The deposition process can include a deposition process as described anywhere herein. The treatment step can include a treatment as described anywhere herein. Advantageously, performing such a supercycle can result in an underlayer having a particularly high sp3 carbon content.

[0078] In some embodiments, the precursor comprises an organic compound. In some embodiments, the organic compound comprises a hydrocarbon. In some embodiments, the precursor comprises an aromatic compound. In some embodiments, the aromatic compound is selected from the list consisting of benzene, alkylbenzene, toluene, ethylbenzene, xylene, durene, aniline, phenol, benzoic acid, biphenyl, mesitylene, styrene, toluidine, toluic acid, cresol, and naphthalene. In some embodiments, the aromatic compound comprises 1,2,4-trimethylbenzene. In some embodiments, the precursor comprises an alkane. In some embodiments, the precursor comprises octane. In some embodiments, the precursor comprises an aromatic compound.

[0079] In some embodiments, the precursor comprises a cyclic compound selected from the list consisting of substituted or unsubstituted cyclic dienes. Examples of unsubstituted cyclic dienes include 1,3-cyclooctadiene and 1,3-cyclohexadiene. Examples of substituted cyclic dienes include alkyl-substituted cyclic dienes such as methylcyclohexadiene, terpinene, and phellandrene. Other examples of substituted cyclic dienes include alkyl-substituted and alkenyl-substituted cyclic dienes such as limonene.

[0080] In some embodiments, the precursor comprises a polycyclic hydrocarbon, such as dicyclopentadiene.

[0081] In some embodiments, the precursors include branched alkenes such as myrcene, 2-methyl-2-butene, 2,3-dimethyl-2-butene, and 2,3-dimethyl-1,3-butadiene.

[0082] In some embodiments, the precursor is selected from the list consisting of benzene, alkylbenzene, toluene, ethylbenzene, xylene, durene, aniline, phenol, benzoic acid, biphenyl, mesitylene, styrene, toluidine, toluic acid, cresol, and naphthalene. In some embodiments, the precursor is selected from the list consisting of o-xylene, m-xylene, and p-xylene. The same applies to toluic acid and cresol.

[0083] In some embodiments, the precursor comprises an alkylbenzene. In some embodiments, the alkylbenzene comprises trimethylbenzene. In some embodiments, the alkylbenzene comprises 1,2,4-trimethylbenzene.

[0084] In some embodiments, the precursor comprises a hydrocarbon. In some embodiments, the precursor comprises an alkane. In some embodiments, the precursor comprises a straight-chain alkane. In some embodiments, the precursor comprises a branched alkane. In some embodiments, the precursor comprises one or more of methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane, and decane.

[0085] In some embodiments, the precursor comprises an aliphatic hydrocarbon.

[0086] In some embodiments, the precursor comprises bicyclo[2.2.2]octane. In some embodiments, the bicyclo[2.2.2]octane comprises one or more reactive substituents, for example, at the 1- or 1,4-positions. Suitable reactive substituents can be selected from the list consisting of -F, -Cl, -Br, -I, -OH, -CHOH, -NH, -CHNH, -PH, -CHPH, -CHSH, -SH, -CHO, -COOH, and -COCl.

[0087] In some embodiments, employing such precursors can increase the sp3 carbon content in the underlayer.

[0088] In some embodiments, the precursor comprises cubane. In some embodiments, the cubane comprises one or more reactive substituents, for example, at the 1- or 1,4-positions. Suitable reactive substituents can be selected from the list consisting of -F, -Cl, -Br, -I, -OH, -CHOH, -NH, -CHNH, -PH, -CHPH, -CHSH, -SH, -CHO, -COOH, and -COCl. In some embodiments, employing such a precursor can increase the sp3 carbon content in the underlayer.

[0089] In some embodiments, the precursor comprises neopentane. In some embodiments, the neopentane comprises one or more reactive substituents on a terminal carbon atom. Suitable reactive substituents can be selected from the list consisting of -F, -Cl, -Br, -I, -OH, -CHOH, -NH, -CHNH, -PH, -CHPH, -CHSH, -SH, -CHO, -COOH, and -COCl. In some embodiments, employing such a precursor can increase the sp3 carbon content in the underlayer.

[0090] In some embodiments, the precursor comprises a single arene ring. In some embodiments, the single arene ring comprises one or more reactive substituents. In some embodiments, the one or more reactive substituents can be selected from the list consisting of -F, -Cl, -Br, -I, -CHF, -CHCl, -CHBr-, -CHI, -OH, -CHOH, -NH, -CHNH, -PH, -CHPH, -CHSH, -SH, -CHO, -COOH, and -COCl. In some embodiments, such precursors can increase the sp2 carbon content in the underlayer.

[0091] In some embodiments, the precursor contains two or more fused arene rings, i.e., each ring contains one or more carbon atoms that are also contained in another arene ring. In some embodiments, such precursors contain one or more reactive substituents. In some embodiments, the one or more reactive substituents can be selected from the list consisting of -F, -Cl, -Br, -I, -CHF, -CHCl, -CHBr-, -CHI, -OH, -CHOH, -NH, -CHNH, -PH, -CHPH, -CHSH, -SH, -CHO, -COOH, and -COCl. In some embodiments, such precursors can increase the sp2 carbon content in the underlayer.

[0092] In some embodiments, the precursor comprises a fullerene. In some embodiments, such precursor comprises one or more reactive substituents. In some embodiments, the one or more reactive substituents can be selected from the list consisting of -F, -Cl, -Br, -I, -CHF, -CHCl, -CHBr-, -CHI, -OH, -CHOH, -NH, -CHNH, -PH, -CHPH, -CHSH, -SH, -CHO, -COOH, and -COCl. In some embodiments, such precursor can increase the sp2 carbon content in the underlayer.

[0093] In some embodiments, the precursor comprises a diene. The diene can include two carbon-carbon double bonds. In some embodiments, such precursors include one or more reactive substituents. In some embodiments, the one or more reactive substituents can be selected from the list consisting of -F, -Cl, -Br, -I, -CHF, -CHCl, -CHBr-, -CHI, -OH, -CHOH, -NH, -CHNH, -PH, -CHPH, -CHSH, -SH, -CHO, -COOH, and -COCl. In some embodiments, such precursors can increase the sp2 carbon content in the underlayer.

[0094] In some embodiments, the precursor comprises an allene. In some embodiments, such precursors comprise one or more reactive substituents. In some embodiments, the one or more reactive substituents can be selected from the list consisting of -F, -Cl, -Br, -I, -CHF, -CHCl, -CHBr-, -CHI, -OH, -CHOH, -NH, -CHNH, -PH, -CHPH, -CHSH, -SH, -CHO, -COOH, and -COCl. In some embodiments, such precursors can increase the sp2 carbon content in the underlayer.

[0095] In some embodiments, the precursor comprises an alkyne. In some embodiments, such precursor comprises one or more reactive substituents. In some embodiments, the one or more reactive substituents can be selected from the list including -F, -Cl, -Br, -I, -CHF, -CHCl, -CHBr-, -CHI, -OH, -CHOH, -NH, -CHNH, -PH, -CHPH, -CHSH, -SH, -CHO, -COOH, and -COCl. In some embodiments, such precursor can increase the sp2 carbon content in the underlayer.

[0096] [ka]

[0097] In some embodiments, the precursor comprises a compound having the general formula (Formula 1) above, where R1, R2, and R3 are independently selected from H and hydrocarbyl. In some embodiments, R3 is H, and R1 and R2 are independently selected from H and hydrocarbyl. In some embodiments, hydrocarbyl is selected from alkyl, alkenyl, alkynyl, and aryl. In some embodiments, R3 is H, R1 is aryl, and R2 is alkyl. In some embodiments, R2 and R3 are equal. In some embodiments, R1 is aryl, and R2 and R3 are methyl. In some embodiments, the precursor comprises 2-hydroxy-2-methylpropiophenone.

[0098] In some embodiments, the precursor is selected from alkyl benzenes, such as 1,2,4-trimethylbenzene, and organic acid anhydrides, such as 2-hydroxy-2-methylpropiophenone.

[0099] In some embodiments, deposition processes according to embodiments of the present disclosure can further include providing a dopant precursor. In some embodiments, the dopant precursor can be provided to the reaction chamber. Alternatively, the dopant precursor can be provided to a remote plasma source or both. In some embodiments, the dopant precursor is provided to the reaction chamber continuously. In some embodiments, the dopant precursor is provided to the reaction chamber in multiple individual dopant precursor pulses. The dopant precursor includes a dopant. Thus, a dopant-containing underlayer can be formed. For example, the underlayer can include 0.1 to 1.0 atomic percent of the dopant, or 1.0 to 5.0 atomic percent of the dopant, or 5.0 to 20.0 atomic percent of the dopant.

[0100] In some embodiments, the dopant is selected from the list consisting of F, Ge, Cs, Bi, Sn, Hf, In, Sb, Te, Br, and I.

[0101] In some embodiments, the plasma gas comprises a noble gas such as He, Ne, Ar, Kr, and Xe, hi some embodiments, the noble gas comprises argon.

[0102] In some embodiments, the plasma gas further comprises hydrogen. In some embodiments, the plasma gas comprises a noble gas and hydrogen. For example, the plasma gas can comprise argon and hydrogen.

[0103] In some embodiments, the plasma gas includes Ar. In some embodiments, the plasma gas includes He. In some embodiments, the plasma gas includes Ar and H2. In some embodiments, the plasma gas includes Ar and N2. In some embodiments, the plasma gas includes Ar, H2, and N2. In some embodiments, the plasma gas includes He and H2. In some embodiments, the plasma gas includes He, H2, and N2. In some embodiments, the plasma gas includes Ar, H2, and formic acid. In some embodiments, the plasma gas includes Ar, N2, and formic acid.

[0104] In some embodiments, the plasma can be a remote plasma or an indirect plasma, and the substrate can be exposed to plasma-generated species consisting essentially of radicals. Any plasma gas as disclosed herein can be employed in a remote or indirect plasma configuration. In some embodiments, the plasma gas comprises a mixture of argon and H2. When a remote or indirect plasma is employed, the substrate can be separated from the plasma by a mesh, perforated plate, or the like.

[0105] In some embodiments, the plasma gas further comprises one or more reactive gases such as O2, O3, H2O, NH3, H2, CO2, N2O, H2S, formic acid, and acetone.

[0106] In some embodiments, the precursor pulse can include multiple subsequent micropulses that involve alternating exposure of the substrate to reactive species from the precursor and to reactive species from a plasma gas that does not include the precursor.

[0107] For example, when using capacitively coupled DC plasma, micropulsing can be used to control the number of ions reaching the substrate surface, thereby controlling dangling bonds in the carbon film. This, in turn, can affect the etch rate of the carbon film and its adhesion to the resist deposited thereon. The resist can be a spin-on resist or a dry resist. A spin-on resist can be applied to the substrate via spin coating. A dry resist can be applied to the substrate via a vapor deposition technique such as molecular layer deposition. Additionally or alternatively, micropulsing can be used to control one or more of the growth rate and composition of the carbon film.

[0108] In some embodiments, the underlayer consists essentially of amorphous carbon.

[0109] Underlayers according to embodiments of the present disclosure can include carbon in various phases, crystalline structures, and / or morphologies, including one or more of cubic / diamond (sp3) carbon, hexagonal / lonsdaleite (sp3) carbon, graphitic (sp2) carbon, aC:H, nanocrystalline graphitic carbon (sp2), fullerene (sp2) carbon, and amorphous (sp3+sp2) carbon.

[0110] In some embodiments, the underlayer formed in accordance with embodiments of the present disclosure may have a viscosity of 1 mJ / m 2 ~5mJ / m 2 or 1 mJ / m 2 ~3mJ / m 2 and a polar surface energy of 35 mJ / m 2 ~40mJ / m 2 This is about 17 mJ / m 2 and a polar surface energy of approximately 38 mJ / m 2 This should be compared to previous amorphous carbon hard masks which may have a dispersive surface energy of 0.1.

[0111] In some embodiments, at least 50 atomic percent of the carbon in the underlayer is sp3 carbon, hi some embodiments, at least 60, 70, 80, 90, 95, or 99 atomic percent of the carbon in the underlayer is sp3 carbon.

[0112] In some embodiments, the underlayer comprises one or more of amorphous carbon, microcrystalline carbon, polycrystalline carbon, a carbon-containing polymer, a carbon-containing oligomer, and a carbon-containing cross-linked resin.

[0113] Advantageously, underlayers formed using method embodiments according to the present disclosure exhibit good etch contrast with organometallic resists. Advantageously, underlayers formed using method embodiments according to the present disclosure exhibit dose reduction. Advantageously, underlayers formed using method embodiments according to the present disclosure exhibit low line roughness.

[0114] In some embodiments, and as described herein, the underlayer comprises hydrogen, e.g., at least 1 atomic percent hydrogen up to 10 atomic percent hydrogen, or at least 10 atomic percent hydrogen up to 20 atomic percent hydrogen, or at least 20 atomic percent hydrogen up to 30 atomic percent hydrogen, or at least 30 atomic percent hydrogen up to 40 atomic percent hydrogen, or at least 40 atomic percent hydrogen up to 50 atomic percent hydrogen, or at least 50 atomic percent hydrogen up to 60 atomic percent hydrogen.

[0115] Advantageously, underlayers as described herein can have a high sp3 carbon content and a relatively high hydrogen content.

[0116] In some embodiments, the underlayer consists essentially of amorphous carbon, which may include non-crystalline carbon and hydrogen.

[0117] In some embodiments, the underlayer comprises at least 50 atomic percent carbon. In some embodiments, the underlayer comprises at least 60 atomic percent carbon. In some embodiments, the underlayer comprises at least 70 atomic percent carbon. In some embodiments, the underlayer comprises at least 80 atomic percent carbon. In some embodiments, the underlayer comprises at least 90 atomic percent carbon. In some embodiments, the underlayer comprises at least 95 atomic percent carbon. In some embodiments, the underlayer comprises at least 99 atomic percent carbon. In some embodiments, the underlayer consists essentially of carbon and hydrogen.

[0118] In some embodiments, the underlayer comprises at least 20 atomic percent to at most 60 atomic percent hydrogen and at least 40 atomic percent to at most 80 atomic percent carbon, hi some embodiments, the underlayer comprises at least 30 atomic percent to at most 50 atomic percent hydrogen and at least 50 atomic percent to at most 70 atomic percent carbon.

[0119] In some embodiments, the underlayer includes one or more elements that have a high capture cross section for extreme ultraviolet (EUV) radiation.

[0120] In some embodiments, the underlayer comprises tin (Sn), hi some embodiments, the underlayer comprises an element selected from the list consisting of F, Ge, Hf, In, Sb, Sn, I, Te, Cs, and Bi.

[0121] In some embodiments, the underlayer has a thickness of at least 1 nm to at most 30 nm, or at least 1 nm to at most 2 nm, or at least 2 nm to at most 5 nm, or at least 5 nm to at most 10 nm, or at least 10 nm to at most 20 nm, or at least 20 nm to at most 30 nm.

[0122] Further described herein is a structure comprising a substrate, an underlayer overlying the substrate, and a photosensitive layer overlying the underlayer, wherein the underlayer is formed by a method as described herein.

[0123] An exemplary structure 400 for EUV lithography is described with reference to FIG. 4. The structure 400 includes a substrate 410. The substrate 410 is covered with an ashable hard mask 420. The ashable hard mask 420 is deposited by plasma-enhanced chemical vapor deposition and may include amorphous carbon with a relatively high concentration of sp2 hybridized carbon, e.g., greater than 70 atomic percent sp2 hybridized carbon. An underlayer 430 according to an embodiment of the present disclosure is disposed over the ashable hard mask 420. An EUV resist 440, e.g., an organometallic resist, is disposed over the underlayer 430.

[0124] Further described herein is a system comprising a reaction chamber, a substrate support, and a controller constructed and arranged to cause the system to carry out a method as described herein.

[0125] The methods provided herein may be performed in any suitable system, including system 500 as shown in FIG. 5. Similarly, the structures provided herein may be fabricated in any suitable system, including a reactor as shown in FIG. 5. FIG. 5 is a schematic diagram of an embodiment of a plasma-enhanced atomic layer deposition (PEALD) system, along with programmed control for carrying out the sequences described below, that may be desirably used in some embodiments of the present disclosure. In this diagram, a pair of conductive plate electrodes (2, 4) are provided parallel and facing each other within the interior (11) (reaction zone) of a reaction chamber (3), and a plasma is excited between the electrodes by applying RF power (e.g., at 13.56 MHz and / or 27 MHz) from a power source (25) to one side and electrically grounding the other side (12). A temperature regulator may be provided for the lower stage (2), i.e., the lower electrode. A substrate (1) is placed thereon, and its temperature is maintained constant at a given temperature. The upper electrode (4) can also function as a shower plate, and reactant gases, and / or dilution gases, if present, as well as precursor gases, can be introduced into the reaction chamber (3) through gas lines (21) and (22), respectively, and through the upper electrode (4) (e.g., shower plate). Additionally, a circular duct (13) with an exhaust line (6) is provided within the reaction chamber (3), through which gas within the interior (11) of the reaction chamber (3) is exhausted. Additionally, a transfer chamber (5) is disposed below the reaction chamber (3), and is provided with a gas seal line (24) for introducing a seal gas into the interior (11) of the reaction chamber (3) through the interior (16) of the transfer chamber (5), and a separation plate (14) for separating the reaction zone from the transfer zone is provided. Note that a gate valve, through which a wafer may be transferred into or out of the transfer chamber (5), is omitted from this illustration. The transfer chamber is also provided with an exhaust line 6. In some embodiments, depositing the underlayer and curing the underlayer are performed in one and the same reaction chamber.In some embodiments, forming the underlayer and curing the underlayer occur in separate reaction chambers contained within one and the same system.

[0126] 6 illustrates another embodiment of a system 600 in accordance with an exemplary embodiment of the present disclosure. The system 600 can be configured to perform methods as described herein and / or form structures or device portions as described herein. In the illustrated example, the system 600 includes one or more reaction chambers 602, a first precursor gas source 604, a reactant gas source 606, an optional additional precursor source 608, an exhaust 610, and a controller 612. In some embodiments, the system further includes at least one of a second precursor gas source (not shown) and a second dopant precursor gas source (not shown). The reaction chamber 602 can include an atomic layer deposition (ALD) reaction chamber.

[0127] The first precursor gas source 604 can include a vessel and one or more precursors as described herein, alone or mixed with one or more carrier gases (e.g., noble gases). The reactant gas source 606 can include a container and one or more dopant precursors as described herein, alone or mixed with one or more carrier gases. The optional additional precursor source 608 can include one or more additional precursors or reactants as described herein.

[0128] Although shown with four gas sources 604-608, system 600 can include any suitable number of gas sources. Gas sources 604-608 can be connected to reaction chamber 602 via lines 614-618, which can each include flow controllers, valves, heaters, and the like. Exhaust 610 can include one or more vacuum pumps.

[0129] The controller 612 includes electronic circuitry and software for selectively operating the valves, manifolds, heaters, pumps, and other components included within the system 600. These circuits and components operate to introduce precursor, reactant, and purge gases from their respective sources 604-608. The controller 612 can control the timing of gas pulse sequences, the temperature of the substrate and / or reaction chamber, the pressure within the reaction chamber, and various other operations to provide proper operation of the system 600. The controller 612 can include control software that electrically or pneumatically controls valves to control the flow of precursor, reactant, and purge gases into and out of the reaction chamber 602. The controller 612 can include software or hardware components, such as modules, e.g., FPGAs or ASICs, that perform certain tasks. The modules can advantageously be configured to reside on addressable storage media of the control system and to execute one or more processes as described herein.

[0130] Other configurations of system 600 are possible, including different numbers and types of precursor sources and oxygen reactant sources, and optionally further including a purge gas source. Additionally, it will be appreciated that there are many arrangements of valves, conduits, precursor sources, and purge gas sources that may be used to achieve the goal of selectively feeding gases into reaction chamber 602. Furthermore, as a schematic representation of the system, many components have been omitted for simplicity of illustration, and such components may include, for example, various valves, manifolds, purifiers, heaters, vessels, vents, and / or bypasses.

[0131] During operation of the system 600, a substrate (not shown), such as a semiconductor wafer, is transferred, for example, from a substrate handling system to the reaction chamber 602. Once the substrate is transferred to the reaction chamber 602, one or more gases from gas sources 604-608, such as precursors, reactants, carrier gases, and / or purge gases, are introduced into the reaction chamber 602.

[0132] Referring to FIG. 7, one embodiment of a deposition process is described herein. The plasma gas includes one or more of N2 and noble gases, such as Ar and He. Optionally, the plasma gas further includes one or more reactive gases, such as H2, O2, O3, H2O, and NH3, CO2, N2O, H2S, formic acid, and acetone. The precursor includes 1,2,4-trimethylbenzene. The precursor can be pulsed intermittently. The time between the onset of subsequent pulses is referred to as the cycle time. The cycle time can be at least 0.1 seconds and up to 100 seconds, e.g., 0.5 seconds, 1 second, 5 seconds, 10 seconds, etc. The ratio of precursor pulse duration to cycle time is referred to as the precursor duty cycle. The precursor duty cycle can be, for example, at least 1% and up to 99%, e.g., 10%, 50%, or 90%. Capacitive DC plasma can be used with a plasma power of 50 W to 500 W operating at a frequency of 100 kHz to 100 MHz. The pressure in the reaction chamber can be 150 Pa to 2000 Pa. The plasma gas can include one or more of H2, Ar, He, and N2. Suitable substrate temperatures include temperatures of at least 50°C to a maximum of 200°C, such as temperatures of at least 75°C to a maximum of 150°C. Experimental results advantageously showed smaller critical dimensions and less lateral edge roughness when an underlayer according to an embodiment of the present disclosure was integrated into a structure according to FIG. 4 compared to a reference underlayer based on spin-on glass. Treating the underlayer with O2 plasma for 2 seconds improved adhesion to the organometallic resist, allowing patterns with smaller critical dimensions to be printed without defects, i.e., pattern collapse.

[0133] Referring to FIG. 8 , a schematic representation of an embodiment of a subsystem 800 as described herein is depicted. This can be used, for example, to form a substrate layer as described herein. Additionally or alternatively, it can be employed to etch one or more of a gap-fill fluid and a material layer. The configuration of FIG. 9 can be described as an indirect plasma system. The subsystem 800 includes a reaction chamber 810 separated from a plasma generation space 825 that generates a plasma 820 therein. Specifically, the reaction chamber 810 is separated from the plasma generation space 825 by a showerhead injector, and the plasma 820 is generated between the showerhead injector 830 and a plasma generation space ceiling 826.

[0134] In the configuration shown, the subsystem 800 includes three alternating current (AC) power sources: a high frequency power source 821 and two low frequency power sources 822, 823: a first low frequency power source 822 and a second low frequency power source 823. In the configuration shown, the high frequency power source 821 supplies radio frequency (RF) power to a plasma generation space ceiling 826, the first low frequency power source 822 supplies an AC signal to a showerhead injector 830, and the second low frequency power source 823 supplies an AC signal to a substrate support 840. The substrate 841 is provided on the substrate support 840. The radio frequency power can be provided at a frequency of, for example, 13.56 MHz or higher. The low frequency AC signals of the first low frequency power source 822 and the second low frequency power source 823 can be provided at a frequency of, for example, 2 MHz or lower.

[0135] Process gases, including precursors, plasma gases, or both, can be provided to the plasma generation space 825 through gas lines 860 that pass through the plasma generation space ceiling 826. Active species, such as ions and radicals, generated by the plasma generation space 825 from the process gases pass through holes 831 in the showerhead injector 830 into the reaction chamber 810. Additionally or alternatively, precursors can be provided directly to the reaction chamber 810.

[0136] 9 illustrates a schematic representation of another embodiment of a subsystem 900 as described herein, which can be used, for example, to form a foundation layer as described herein. The configuration of FIG. 9 can be described as a remote plasma system. The subsystem 900 includes a reaction chamber 910 operatively connected to a remote plasma source 925, in which a plasma 920 is generated. Any type of plasma source can be used as the remote plasma source 925, for example, an inductively coupled plasma, a capacitively coupled plasma, or a microwave plasma.

[0137] Specifically, activated species are provided from a remote plasma source 925 to the reaction chamber 910, via an activated species duct 960, to a conical distributor 950, through holes 931 in a shower plate injector 930, and into the reaction chamber 910. Therefore, activated species can be provided to the reaction chamber in a uniform manner.

[0138] In the configuration shown, the subsystem 900 includes three alternating current (AC) power sources: a high frequency power source 921 and two low frequency power sources 922, 923: a first low frequency power source 922 and a second low frequency power source 923. In the configuration shown, the high frequency power source 921 supplies radio frequency (RF) power to the plasma generation space ceiling, the first low frequency power source 922 supplies an AC signal to the showerhead / showerplate injector 930, and the second low frequency power source 923 supplies an AC signal to the substrate support 940. The substrate 941 is provided on the substrate support 940. The RF power can be provided at a frequency of, for example, 13.56 MHz or higher. The low frequency AC signals of the first low frequency power source 922 and the second low frequency power source 923 can be provided at a frequency of, for example, 2 MHz or lower.

[0139] In some embodiments (not shown), an additional RF power source can be electrically connected to the substrate support, and thus a direct plasma can be generated within the reaction chamber.

[0140] Process gases containing precursors, reactants, or both are provided to the remote plasma source 925 by an activated species duct 960. Activated species such as ions and radicals generated from the process gases by the remote plasma source 925 are guided into the reaction chamber 910.

Claims

1. 1. A system constructed and arranged to form an underlayer for lithographic patterning, comprising: a reaction chamber comprising a substrate support constructed and arranged to support a substrate; a substrate transfer robot constructed and arranged to position said substrate on said substrate support; said substrate support constructed and arranged to support said substrate; a plasma gas conduit constructed and arranged to provide a plasma gas from a plasma gas source containing said plasma gas to said reaction chamber; a precursor conduit constructed and arranged to provide a precursor from a precursor source containing said precursor to said reaction chamber; a plasma generator constructed and arranged to generate a plasma within said reaction chamber; a process controller constructed and arranged to cause said system to carry out a deposition process, said deposition process comprising: - providing the plasma gas into the reaction chamber; - continuously generating said plasma in said reaction chamber by said plasma generator and said plasma gas; - continuously generating the plasma in the reaction chamber while providing the precursor to the reaction chamber in a series of individual precursor pulses; The system wherein the underlayer comprises amorphous carbon.

2. The system of claim 1 , wherein the plasma generator comprises an inductively coupled plasma source.

3. The system of claim 1 , wherein the plasma generator comprises a capacitive plasma source.

4. 1. A method for forming an underlayer for lithographic patterning, comprising: - providing a substrate into a reaction chamber; performing a deposition process, - providing a plasma gas into the reaction chamber; - continuously generating a plasma in the reaction chamber by means of the plasma gas; - performing a deposition process comprising: - providing precursors to the reaction chamber in a series of individual precursor pulses while continuously generating the plasma in the reaction chamber; The method wherein the underlayer comprises amorphous carbon.

5. The method of claim 4 , wherein the precursor comprises an organic compound.

6. The method of claim 5 , wherein the organic compound comprises a hydrocarbon.

7. The method of claim 6 , wherein the precursor comprises an aromatic compound.

8. 8. The method of claim 7, wherein the aromatic compound is selected from the list consisting of benzene, alkylbenzenes, toluene, ethylbenzene, xylene, durene, aniline, phenol, benzoic acid, biphenyl, mesitylene, styrene, toluidine, toluic acid, cresol, and naphthalene.

9. The method of claim 7, wherein the aromatic compound comprises 1,2,4-trimethylbenzene.

10. The method of claim 6 , wherein the precursor comprises an alkane.

11. The method of claim 6 , wherein the precursor comprises octane.

12. The method of claim 4 , wherein the plasma gas comprises a noble gas.

13. The method of claim 12 , wherein the plasma gas further comprises hydrogen.

14. The method of claim 4 , wherein the underlayer comprises the amorphous carbon.

15. 5. The method of claim 4, wherein the deposition process results in an initial underlayer having an initial sp3 carbon content, and following the deposition process, the substrate is subjected to a treatment step, which results in a treated underlayer having a treated sp3 carbon content, the treated sp3 carbon content being greater than the initial sp3 carbon content.

16. 16. The method of claim 15, wherein the treating step comprises a plasma treating step comprising generating a treatment plasma and exposing the substrate to one or more active treatment species generated in the treatment plasma.

17. The method of claim 16 , wherein the treatment plasma comprises one or more of an argon plasma and an oxygen plasma.

18. The method of claim 4 , wherein the series of individual precursor pulses comprises a plurality of micro precursor pulses.

19. 1. A method for forming an underlayer for lithographic patterning, comprising: - providing a substrate into a reaction chamber; - carrying out a deposition process, - providing a plasma gas; - continuously generating plasma with the plasma gas to generate activated species; - continuously exposing said substrate to said active species; - performing a deposition process comprising: - providing precursors to the reaction chamber in a series of individual precursor pulses while continuously generating the plasma; The method wherein the underlayer comprises amorphous carbon.

20. 20. The method of claim 19, wherein the plasma gas is provided to a remote plasma unit, the remote plasma unit being operatively connected to the reaction chamber via an activated species duct to continuously provide the activated species to the reaction chamber.

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