Method for treating a substrate

Abstract

To provide methods and related systems for lithographically defining patterns on a substrate.SOLUTION: An exemplary method includes forming a structure. The method includes providing a substrate to a reaction chamber. The substrate comprises a semiconductor and a surface layer. The surface layer comprises amorphous carbon. The method further comprises forming a barrier layer on the surface layer, and depositing a metal-containing layer on the substrate. The metal- containing layer comprises oxygen and a metal.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates generally to surface treatments, and more particularly to surface treatments to form structures. Further, the present disclosure relates to structures including treated surfaces. [Background technology]

[0002] During the manufacture of electronic devices, fine patterns of features can be formed on the surface of a substrate by forming a pattern on the surface of the substrate and etching material from the surface of the substrate, for example, using a gas-phase etching process. As the density of devices on a substrate increases, it becomes increasingly desirable to form features with smaller dimensions. Therefore, there is a need for improved methods for forming features having small dimensions on a substrate.

[0003] Any discussion of problems and solutions presented in this section is included in this disclosure solely for the purpose of providing a context for the disclosure and should not be construed as an admission that any or all of the discussions were publicly known at the time the invention was made. Summary of the Invention [Means for solving the problem]

[0004] Various embodiments of the present disclosure relate to methods for treating surfaces. While the manner in which various embodiments of the present disclosure address the shortcomings of prior methods and structures is discussed in more detail below, various embodiments of the present disclosure can generally be used to improve various aspects of radiation-sensitive layers, such as desired etch selectivity, low linewidth roughness (LWR), pattern quality (low number of defects, high pattern fidelity), compatibility with integration, and / or stability during EUV lithography processing (e.g., during any post-exposure bake (PEB)).

[0005] According to an exemplary embodiment of the present disclosure, a method for forming a structure is described herein. The method includes (in that order) providing a substrate to a reaction chamber, forming a barrier layer on a surface layer, and depositing a metal-containing layer on the substrate. The substrate includes a semiconductor and a surface layer. The surface layer includes amorphous carbon. The metal-containing layer includes oxygen and a metal.

[0006] In some embodiments, forming the barrier layer on the surface layer comprises exposing the surface layer to a nitrogen-containing plasma, resulting in the formation of a plasma-modified surface layer.

[0007] In some embodiments, forming a barrier layer on the surface layer comprises depositing an intermediate layer on the plasma-modified surface layer.

[0008] In some embodiments, forming a barrier layer on the surface layer includes depositing an intermediate layer on the surface layer.

[0009] In some embodiments, forming the barrier layer on the surface layer further comprises exposing the intermediate layer to a nitrogen-containing plasma, thus forming a plasma-modified intermediate layer.

[0010] In some embodiments, depositing the intermediate layer comprises a cyclic process comprising multiple subsequent cycles, wherein one cycle comprises an intermediate layer precursor pulse and an intermediate layer reactant pulse, wherein the intermediate layer precursor pulse comprises providing the intermediate layer precursor to the reaction chamber, and wherein the intermediate layer reactant pulse comprises providing the intermediate layer reactant to the reaction chamber.

[0011] In some embodiments, the intermediate layer precursor is selected from the list consisting of a silicon precursor, a titanium precursor, and a tantalum precursor.

[0012] In some embodiments, the interlayer reactant is an oxygen reactant.

[0013] In some embodiments, the oxygen reactant comprises a gas species selected from O2, O3, H2O, H2O2, N2O, NO, CO2, CO, and NO2.

[0014] In some embodiments, neither the step of providing an interlayer precursor to the reaction chamber nor the step of providing an interlayer reactant to the reaction chamber includes generating a plasma within the reaction chamber.

[0015] In some embodiments, the intermediate layer has a thickness of 3 nm or less.

[0016] In some embodiments, the method further comprises depositing a photoresist layer over the metal-containing layer.

[0017] In some embodiments, the photoresist layer comprises an EUV photoresist.

[0018] In some embodiments, depositing a metal-containing layer on a substrate comprises a cyclic deposition process comprising multiple subsequent cycles, wherein one cycle comprises a metal-containing layer precursor pulse and a metal-containing layer reactant pulse.

[0019] In some embodiments, at least one of the metal-containing layer precursor pulse and the metal-containing layer reactant pulse is preceded by a purge.

[0020] In some embodiments, the metal-containing layer precursor pulse comprises providing a metal-containing precursor to the reaction chamber. The metal-containing precursor has the general formula M[R(C x H y )n]4, wherein M is selected from Ti, Ta, Hf, Zn, and Zr, R is selected from OCH and N, x is 1 to 2, y is 3 to 6, and n is 2 to 3.

[0021] In some embodiments, the metal-containing layer reactant pulse includes providing a metal-containing layer reactant to the reaction chamber. Suitably, the metal-containing layer reactant may in some embodiments be selected from HO, O, and HO.

[0022] In some embodiments, the metal-containing layer reactant pulse comprises generating a plasma in the reaction chamber, the plasma being selected from a hydrogen-containing plasma and an oxygen-containing plasma.

[0023] In some embodiments, forming a barrier layer on the surface layer comprises exposing the substrate to radicals.

[0024] In some embodiments, the metal-containing layer has a thickness of less than 5 nm.

[0025] Further described herein is a system comprising a reaction chamber, a gas injection system fluidly connected to the reaction chamber, a first gas supply for introducing a precursor and optionally a carrier gas into the reaction chamber, a second gas supply for introducing a mixture of one or more additional gases into the reaction chamber, an exhaust, and a controller configured to control gas flow into the gas injection system and to cause the system to perform a method as described herein.

[0026] These and other embodiments will be readily apparent to those skilled in the art from the following detailed description of specific embodiments which refer to the accompanying drawings, and the invention is not limited to any particular embodiment disclosed. [Brief explanation of the drawings]

[0027] A more complete understanding of the exemplary embodiments of the present disclosure can be obtained by reference to the detailed description and claims when considered in conjunction with the following illustrative figures.

[0028] [Figure 1] FIG. 1 illustrates some embodiments of structures formed by methods as described herein. [Figure 2] FIG. 2 illustrates one embodiment of a method (200) for forming a structure as described herein. [Figure 3] FIG. 3 illustrates one embodiment of a method (300) for depositing a barrier layer as described herein. [Figure 4] FIG. 4 illustrates one embodiment of a method (400) for depositing a barrier layer as described herein. [Figure 5] FIG. 5 illustrates one embodiment of a method (500) for depositing an intermediate layer as described herein. [Figure 6] FIG. 6 shows experimental results (particularly transmission electron micrographs) of a structure used employing a method according to one embodiment of the present disclosure. [Figure 7] FIG. 7 shows experimental results (particularly transmission electron micrographs) of a structure used employing a method according to one embodiment of the present disclosure. [Figure 8] FIG. 8 shows experimental results (particularly transmission electron micrographs) of a structure used employing a method according to one embodiment of the present disclosure. [Figure 9] FIG. 9 shows experimental results (particularly transmission electron micrographs) of a structure used employing a method according to one embodiment of the present disclosure. [Figure 10] FIG. 10 illustrates a structure (1000) according to an exemplary embodiment of the present disclosure. [Figure 11] FIG. 11 shows an exemplary process flow (1100) for depositing a metal-containing layer or portion thereof by plasma-enhanced chemical vapor deposition. [Figure 12] FIG. 12 shows an exemplary process flow (1200) that includes exposing a substrate to radicals.

[0029] 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 THE INVENTION

[0030] While certain specific embodiments and examples are disclosed below, it will be understood that the invention extends beyond the specifically disclosed embodiments and / or uses thereof, 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 set forth below.

[0031] As used herein, the term "substrate" may refer to any underlying material(s) including one or more layers and / or any underlying material(s) onto which one or more layers may be deposited. The substrate may include a bulk material such as silicon (e.g., single crystal silicon), other Group IV materials such as germanium, or compound semiconductor materials such as GaAs, and may include one or more layers above or below the bulk material. For example, the substrate may include a patterning stack of several layers above the bulk material. The patterning stack may vary depending on the application. Furthermore, the substrate may additionally or alternatively include various features (such as depressions, lines, and the like) formed in or on at least a portion of the layers of the substrate.

[0032] In some embodiments, a "film" refers to a layer extending in a direction perpendicular to the thickness direction. In some embodiments, a "layer" refers to a material having a certain thickness formed on a surface, or a synonym for a film or non-film structure. A film or layer may be composed of a single individual film or layer or multiple films or layers having certain properties, and the boundaries between adjacent films or layers may or may not be clear, and may or may not be established based on physical, chemical, and / or other characteristics, the formation process or order, and / or the function or purpose of the adjacent film or layer. Furthermore, a layer or film may be continuous or discontinuous.

[0033] In this disclosure, "gas" may include materials that are gases, vaporized solids, and / or vaporized liquids at ambient temperature and pressure, and may consist of a single gas or a mixture of gases, depending on the circumstances. Gases other than process gases, i.e., gases introduced without passing through a gas distribution assembly (such as a showerhead, other gas distribution device, or the like), may be used, for example, to seal the reaction space and may include seal gases such as noble gases.

[0034] In some cases (such as in the context of materials deposition), the term "precursor" can refer to a compound that participates in a chemical reaction to produce another compound, particularly a compound that constitutes the membrane matrix or backbone of the membrane, while the term "reactant" can refer to a compound that, in some cases other than the precursor, activates the precursor, modifies the precursor, or catalyzes the reaction of the precursor; the reactant may contribute elements (such as O, N, C) to the membrane matrix and become part of the membrane matrix. In some cases, the terms "precursor" and "reactant" can be used interchangeably.

[0035] It will be understood that the term "metal-containing layer precursor" refers to a precursor used during the deposition of a metal-containing layer. Similarly, the term "metal-containing layer reactant" refers to a reactant used during the deposition of a metal-containing layer.

[0036] The term "cyclic deposition process" or "cyclical deposition process" may refer to the sequential introduction of precursors (and / or reactants) into a reaction chamber to deposit layers on a substrate, and includes processing techniques such as atomic layer deposition (ALD), cyclical chemical vapor deposition (cyclic CVD), and hybrid cyclic deposition processes that include ALD and cyclical CVD components.

[0037] The term "atomic layer deposition" may refer to a vapor deposition process in which deposition cycles (typically multiple successive deposition cycles) are performed in a process chamber. As used herein, the term "atomic layer deposition" is also meant to include processes indicated by related terms such as chemical vapor deposition atomic layer deposition, atomic layer epitaxy (ALE), molecular beam epitaxy (MBE), gas source MBE, or metalorganic MBE, as well as chemical beam epitaxy when performed using alternating pulses of precursor(s) / reactive gas(es), and purge (e.g., inert carrier) gas(es).

[0038] Generally, for an ALD process, during each cycle, a precursor is introduced into the reaction chamber and chemisorbed onto the deposition surface (e.g., a substrate surface, which may contain previously deposited material or other materials from a previous ALD cycle), forming a monolayer or submonolayer of material that does not readily react with additional precursors (i.e., a self-limiting reaction). In some cases, a reactant (e.g., another precursor or reactant gas) may then be introduced into the process chamber for use in converting the chemisorbed precursor to the desired material on the deposition surface. The reactant may be capable of further reaction with the precursor. Purging steps may be utilized during one or more cycles (e.g., during each step of each cycle) to remove any excess precursor from the process chamber and / or to remove any excess reactants and / or reaction by-products from the reaction chamber.

[0039] In this disclosure, two numbers for any variable can constitute a workable range for that variable, and any range stated may include or exclude endpoints. Additionally, in some embodiments, any value for a stated variable (whether or not it is stated with "about") may refer to an exact or approximate value, and may include equivalents, and may refer to an average, median, representative, or key value, etc. Furthermore, in this disclosure, the terms "comprise," "comprised of," and "having" can, in some embodiments, independently refer to "typically or broadly include," "comprise," "consist essentially of," or "consist." According to aspects of the present disclosure, any defined meaning of a term does not necessarily exclude the ordinary and customary meaning of that term.

[0040] Described herein are methods for forming structures that include (in that order): 1) providing a substrate including a surface layer in a reaction chamber, 2) forming a barrier layer on the surface layer, and 3) depositing a metal-containing layer on the substrate.

[0041] In some embodiments, the surface layer comprises silicon, oxygen, and carbon. In some embodiments, the surface layer comprises a carbon-containing material. In some embodiments, the surface layer comprises a material selected from amorphous carbon, silicon oxycarbide (SiOC), and silicon carbonitride (SICN). In some embodiments, the surface layer comprises amorphous carbon. In some embodiments, the surface layer has a carbon content of greater than 80 atomic %, or greater than 90 atomic %, or greater than 95 atomic %, or greater than 99 atomic %. In some embodiments, the surface layer consists essentially of carbon.

[0042] As used herein, SiOC, unless otherwise stated, is not intended to limit, restrict, or define the bonding or chemical state, e.g., the oxidation state, of any of Si, O, C, and / or any other elements in the film. Furthermore, in some embodiments, SiOC thin films may include one or more elements, such as H or N, in addition to Si, O, and / or C.

[0043] As used herein, SiCN, unless otherwise stated, is not intended to limit, restrict, or define the bonding or chemical state, e.g., the oxidation state, of any of Si, C, N, and / or any other elements in the film. Furthermore, in some embodiments, SiCN thin films may include one or more elements, such as H, in addition to Si, C, and N.

[0044] In some embodiments, the methods described herein include depositing a surface layer on a substrate. In some embodiments, the surface layer is deposited by a chemical vapor deposition process in which precursors and reactants are sequentially provided to a reaction chamber. In some embodiments, the surface layer is deposited by a cyclic deposition process, such as an ALD process. For example, depositing the surface layer can include pulsing a carbon precursor into the reaction chamber, allowing the carbon precursor to react with the surface of the substrate, and purging any unreacted precursor and / or by-products. In some embodiments, the surface layer has a thickness of up to 3 nm, e.g., at least 1 nm to a maximum of 2 nm.

[0045] In some embodiments, forming a barrier layer on the surface layer includes exposing the substrate to radicals. For example, radicals can be generated in a remote plasma, such as a remote hydrogen plasma, a remote nitrogen plasma, a remote oxygen plasma, or a remote noble gas plasma. Exemplary noble gases include He, Ne, Ar, Kr, and Xe. As a result, the method as described herein can include forming the barrier layer by exposing the substrate to one or more of hydrogen radicals, nitrogen radicals, oxygen radicals, and noble gas radicals (such as He radicals, Ne radicals, Ar radicals, Kr radicals, and Xe radicals). Such radical exposure can advantageously improve nucleation on amorphous carbon-containing surface layers, such as CH-terminated amorphous carbon layers, without damaging them.

[0046] In some embodiments, forming a barrier layer on the surface layer includes at least one of exposing the substrate to a nitrogen-containing plasma and depositing an intermediate layer on the substrate. Advantageously, forming a barrier layer on the surface layer results in suppression of intermixing between the metal-containing layer and the surface layer. Indeed, in prior art techniques, the metal-containing layer can be deposited by relatively reactive plasma processing techniques, such as plasma-enhanced atomic layer deposition (PEALD) processes or plasma-enhanced chemical vapor deposition (PECVD) processes employing O2 or H2 plasma. Such plasma-based deposition processes can interact with carbon-containing surface layers, such as amorphous carbon, to form volatile by-products, such as gases containing carbon and at least one of oxygen and hydrogen. Therefore, such plasma-based deposition processes can result in a reduction in the thickness of such surface layers and / or surface roughening. Additionally, thickness variations across the substrate surface can occur. Additionally or alternatively, a carbon concentration gradient can result in the metal-containing layer being deposited on the surface layer. In this method, the barrier layer advantageously protects the carbon-containing surface layer, thus reducing surface roughness and carbon incorporation in the metal-containing layer.

[0047] In some embodiments, forming a barrier layer on the surface layer includes exposing the surface layer to a nitrogen-containing plasma. As a result, a plasma-modified surface layer is formed. In other words, by exposing the substrate to a nitrogen-containing plasma, a portion of the surface layer can be converted into a barrier layer. While exposing the substrate to a nitrogen-containing plasma gas, a nitrogen-containing gas or gas mixture can be used as the plasma gas. Suitable nitrogen-containing gases or gas mixtures include at least one of N2, NH3, and NO.

[0048] In some embodiments, exposing the substrate to a nitrogen-containing plasma comprises exposing the substrate to a direct nitrogen-containing plasma.

[0049] In some embodiments, forming the barrier layer on the surface layer includes exposing the surface layer to nitrogen radicals. The nitrogen radicals may be generated by a remote plasma, such as an inductively coupled plasma. In other embodiments, the radicals may be generated by a hot wire source, for example.

[0050] In some embodiments, forming the barrier layer on the surface layer comprises exposing the surface layer to one or more nitrogen-containing agents (i.e., one or more nitrogen-containing molecules, radicals, or ions). Exemplary nitrogen-containing agents can have a chemical formula including N, and optionally one or more of C, O, and H. In some embodiments, forming the barrier layer on the surface layer comprises exposing the surface layer to a plasma generated in a reaction chamber. Suitably, the plasma gas used, including the nitrogen-containing agent, can have a chemical formula including N, and optionally one or more of C, O, and H.

[0051] In some embodiments, forming the barrier layer on the surface layer includes depositing an intermediate layer on the surface layer. Depositing the intermediate layer can, in some embodiments, include employing a cyclical process. The cyclical deposition process includes one or more subsequent cycles. A cycle includes a barrier precursor pulse and a barrier reactant pulse. The barrier precursor pulse includes providing a barrier precursor to the reaction chamber. The barrier reactant pulse includes providing a barrier reactant to the reaction chamber. In some embodiments, the barrier precursor pulse and the barrier reactant pulse are separated by a purge. In some embodiments, subsequent cycles are separated by a purge. During the purge, the reaction chamber is advantageously evacuated or filled with a process gas (e.g., a noble gas such as argon).

[0052] In some embodiments, forming the barrier layer on the surface layer comprises a thermal process, such as a thermal atomic layer deposition process or a thermal chemical vapor deposition process. In other words, and in some embodiments, forming the barrier layer on the surface layer does not employ a plasma.

[0053] The barrier precursor, in some embodiments, can be selected from the list consisting of a silicon precursor, a titanium precursor, and a tantalum precursor.

[0054] In some embodiments, depositing the intermediate layer can include employing a radical-enhanced cyclic process. Such a radical-enhanced cyclic deposition process can advantageously improve nucleation on amorphous carbon-containing surface layers, such as CH-terminated amorphous carbon layers, without damaging them. The radical-enhanced cyclic deposition process includes one or more subsequent cycles. One cycle includes a barrier precursor pulse and a barrier reactant pulse. The barrier precursor pulse includes providing a barrier precursor to the reaction chamber. The barrier reactant pulse includes providing a barrier reactant to the reaction chamber. At least one of the barrier precursor pulse and the barrier reactant pulse includes exposing the substrate to radicals. In some embodiments, the barrier precursor includes radicals. In some embodiments, the barrier reactant includes radicals. In some embodiments, the barrier precursor pulse and the barrier reactant pulse are separated by a purge. In some embodiments, subsequent cycles are separated by a purge. During the purge, the reaction chamber is advantageously evacuated or filled with a process gas (e.g., a noble gas such as argon).

[0055] The barrier precursor, in some embodiments, can be selected from the list consisting of a silicon precursor, a titanium precursor, and a tantalum precursor.

[0056] In some embodiments, the barrier precursor pulse comprises exposing the substrate to a barrier precursor without exposing the substrate to radicals, and the barrier reactant pulse comprises exposing the substrate to a barrier reactant containing radicals. Suitable radicals include hydrogen radicals, oxygen radicals, nitrogen radicals, and noble gas radicals such as He radicals, Ne radicals, Ar radicals, Kr radicals, and Xe radicals.

[0057] In some embodiments, the silicon precursor comprises an alkylaminosilane. Suitable alkylaminosilanes include bis(diethylamino)silane and diisopropylaminosilane.

[0058] In some embodiments, the silicon precursor comprises an alkoxysilane. Suitable alkoxysilanes include dimethyldimethoxysilane and (3-methoxypropyl)trimethoxysilane.

[0059] In some embodiments, the silicon precursor comprises an alkoxysiloxane. Suitable alkoxysiloxanes include 1,3-dimethoxytetramethyldisiloxane.

[0060] In some embodiments, the silicon precursor comprises alkyl- and alkoxy-substituted siloxanes, such as 1,3-dimethoxytetramethyldisiloxane.

[0061] In some embodiments, the silicon precursor comprises an alkyl-substituted cyclosiloxane, such as octamethylcyclotetrasiloxane.

[0062] In some embodiments, the silicon precursor comprises an alkoxysilyl-substituted alkane, such as 1,2-bis(triethoxysilyl)ethane.

[0063] In some embodiments, the silicon precursor comprises a silane containing an aminoalkyl group and an alkoxy group (such as 3-aminopropyltrimethoxysilane).

[0064] In some embodiments, the titanium precursor comprises at least one alkoxy ligand. Exemplary titanium precursors include titanium tetraisopropoxide.

[0065] In some embodiments, the titanium precursor comprises one or more alkylamine ligands. Suitable titanium precursors include tetrakis(dimethylamido)titanium(IV).

[0066] In some embodiments, the tantalum precursor comprises one or more alkylamine ligands. Suitable tantalum precursors include pentakis(dimethylamino)tantalum(V).

[0067] The barrier reactant can include or be an oxygen reactant in some embodiments. Exemplary oxygen reactants include oxygen-containing gases (e.g., O, O), oxygen radicals, oxygen ions, or gas mixtures (e.g., nitrogen and oxygen mixtures, nitrogen and ozone mixtures, noble gas and oxygen mixtures, noble gas and ozone mixtures, etc.). In some embodiments, the oxygen reactant comprises a gas species selected from O, O, HO, HO, CO, CO, NO, and NO.

[0068] In some embodiments, the barrier precursor can be selected from a silicon precursor and a metal precursor. In some embodiments, the barrier precursor can be selected from a silicon precursor, a tantalum precursor, a hafnium precursor, a tin precursor, a titanium precursor, an aluminum precursor, and a zinc precursor. Such barrier precursors can be used with oxygen reactants as described herein. Additionally or alternatively, such precursors can be used with reactants containing one or more of oxygen, nitrogen, and carbon. Thus, in some embodiments, the barrier layer comprises one or more oxynitrides, carbonitrides, or oxycarbonitrides selected from Si, Ta, Hf, Sn, Ti, Al, and Zn.

[0069] In some embodiments, forming a barrier layer includes using a barrier precursor selected from a silicon precursor, a titanium precursor, and a tantalum precursor. Therefore, a barrier layer including one or more of silicon, titanium, and tantalum can be formed. Advantageously, silicon, titanium, and tantalum can form volatile by-products when exposed to fluorine-containing chemicals or plasmas. Therefore, a barrier layer including one or more of silicon, titanium, and tantalum can be easily etched using common etching chemistries.

[0070] In some embodiments, the barrier precursor contains an alkoxide ligand. In some embodiments, the barrier precursor includes a C1-C4 alkoxide ligand. In some embodiments, the barrier precursor includes an isopropoxide ligand. In some embodiments, the barrier precursor is selected from silicon isopropoxide, titanium isopropoxide, and tantalum isopropoxide.

[0071] In some embodiments, the barrier precursor has the general formula M[R(C x H y ) n ]4, wherein M is selected from Ti, Ta, Hf, Zn, and Zr, R is selected from OCH and N, wherein x is 1-2, wherein y is 3-6, and wherein n is 2-3.

[0072] In some embodiments, neither the step of providing a barrier precursor to the reaction chamber nor the step of providing a barrier reactant to the reaction chamber includes generating a plasma within the reaction chamber. In other words, and in some embodiments, the step of depositing the intermediate layer employs a thermal process. This can advantageously improve the properties of the intermediate layer, for example, by reducing or completely avoiding intermixing between the surface layer and the intermediate layer.

[0073] In some embodiments, at least one of providing a barrier precursor to the reaction chamber and providing a barrier reactant to the reaction chamber includes providing radicals to the reaction chamber. The radicals may be generated by a remote plasma, such as an inductively coupled plasma. In other embodiments, the radicals may be generated by a hot wire source, for example.

[0074] In some embodiments, at least one of providing a barrier precursor to the reaction chamber and providing a barrier reactant to the reaction chamber comprises generating a plasma in the reaction chamber.

[0075] In some embodiments, the barrier precursor and the barrier reactant are provided to the reaction chamber simultaneously. In some embodiments, a plasma is generated in the reaction chamber while the barrier precursor and the barrier reactant are provided to the reaction chamber simultaneously. In some embodiments, no plasma is generated in the reaction chamber while the barrier precursor and the barrier reactant are provided to the reaction chamber simultaneously.

[0076] If a plasma is generated in the reaction chamber during deposition of the barrier layer, "soft" plasma conditions are advantageously used to minimize thickness reduction of the carbon-containing surface layer and to minimize surface roughening. In particular, in some embodiments, low plasma powers, such as plasma powers of at least 30 W and up to 100 W, can be advantageously used. Of course, these powers apply when the substrate is a 300 mm semiconductor wafer. Those skilled in the art can easily adapt these powers to other substrate sizes, if desired. Additionally or alternatively, in some embodiments, the plasma gas can include a noble gas, such as He, Ne, Ar, Kr, or Xe. In some embodiments, the plasma gas includes Ar. In some embodiments, the plasma gas consists essentially of a noble gas. In some embodiments, the plasma gas consists essentially of Ar. Additionally or alternatively, relatively short plasma exposure times can be used, such as plasma exposure times of at least 0.01 seconds and up to 1.0 seconds, or at least 0.01 seconds and up to 0.1 seconds, or at least 0.1 seconds and up to 1.0 seconds. When a cyclic deposition process is used, the times noted above may, in some embodiments, advantageously refer to the total plasma time during deposition of the barrier layer. Additionally or alternatively, and in some embodiments, relatively high pressures (such as pressures of at least 100 Torr and up to 760 Torr) may be used during deposition of the barrier layer.

[0077] In some embodiments, the plasma generated in the reaction chamber during deposition of the barrier layer can be an RF plasma. In some embodiments, the RF plasma can be generated by a power waveform having a fundamental frequency of at least 20 MHz and up to 200 MHz, which can advantageously reduce surface roughness.

[0078] In some embodiments, a microwave plasma is generated in the reaction chamber during deposition of the barrier layer, which can advantageously reduce surface roughness.

[0079] In some embodiments, vacuum ultraviolet light is used to generate a plasma in the reaction chamber during deposition of the barrier layer. Advantageously, such vacuum ultraviolet light-generated plasma can be maintained for a relatively short duration, such as at least 0.01 μs to a maximum of 100 μs, or at least 0.1 μs to a maximum of 10 μs, or at least 0.2 μs to a maximum of 5 μs, or at least 0.5 μs to a maximum of 2 μs. When a cyclic deposition process is used, the aforementioned time period can, in some embodiments, advantageously refer to the time the vacuum ultraviolet light is on during deposition of the barrier layer.

[0080] In some embodiments, forming the barrier layer on the surface layer further comprises depositing an intermediate layer on the surface layer and then exposing the intermediate layer to a nitrogen-containing plasma, thus forming a plasma-modified intermediate layer.

[0081] In some embodiments, forming the barrier layer on the surface layer comprises exposing the surface layer to a nitrogen-containing plasma to form a plasma-modified surface layer, and then depositing the intermediate layer on the plasma-modified surface layer.

[0082] In some embodiments, forming the barrier layer on the surface layer comprises exposing the surface layer to a nitrogen-containing plasma to form a plasma-modified surface layer, then depositing an intermediate layer on the plasma-modified surface layer, and then exposing the intermediate layer to the nitrogen-containing plasma, thus forming the plasma-modified intermediate layer.

[0083] In some embodiments, the metal-containing layer is a layer positioned between a carbon-containing layer, such as an amorphous carbon layer, and a photoresist layer in a patterning stack. A suitable metal-containing layer provides etch contrast for the carbon-containing layer and adequate adhesion to the photoresist layer. Alternatively, the metal-containing layer may be referred to as an etch contrast layer, a separation layer, a patterning aid layer, or simply a layer. In some embodiments, the photoresist layer comprises a metal and oxygen. In some embodiments, the metal-containing layer comprises one or more of a metal oxide, a metal nitride, and a metal oxynitride. The use of a barrier layer and a metal-containing layer between the surface layer and the photoresist can advantageously result in improved patterning quality by reducing or eliminating the occurrence of stochastic effects, such as microbridges and microbreaks. Naturally, the reaction conditions under which the barrier layer is deposited differ from the reaction conditions under which the metal-containing layer is deposited.

[0084] In some embodiments, the metal-containing layer can have a thickness of 5 nm or less, or 3 nm or less, hi some embodiments, the metal-containing layer has a thickness of at least 0.3 nm to a maximum of 3.0 nm, or at least 0.3 nm to a maximum of 0.5 nm, or at least 0.5 nm to a maximum of 1.0 nm, or at least 1.0 nm to a maximum of 1.5 nm, or at least 1.5 nm to a maximum of 2.0 nm, or at least 2.0 nm to a maximum of 2.5 nm, or at least 2.5 nm to a maximum of 3.0 nm.

[0085] In some embodiments, depositing a metal-containing layer comprises a cyclic deposition process including a plurality of subsequent cycles, wherein one cycle in the cyclic deposition process comprises a metal-containing layer precursor pulse and a metal-containing layer reactant pulse. In some embodiments, the metal-containing layer precursor pulse and the metal-containing layer reactant pulse are separated by an intra-cycle purge. In some embodiments, subsequent cycles are separated by an intra-cycle purge. Thus, in some embodiments, at least one of the metal-containing layer precursor pulse and the metal-containing layer reactant pulse is preceded by a purge.

[0086] In some embodiments, forming the metal-containing layer comprises a plasma-enhanced atomic layer deposition (PEALD) process including one or more cycles, wherein one cycle includes exposing the substrate to a metal-containing layer precursor, purging excess precursor from the reaction chamber, exposing the substrate to a noble gas plasma containing reactive species, and purging excess reactive species from the reaction chamber.

[0087] In some embodiments, the metal-containing layer precursor pulse comprises providing a metal-containing precursor to the reaction chamber, the metal-containing precursor having the general formula M[R(C x H y ) n ]4, wherein M is selected from Ti, Ta, Hf, Zn, and Zr, and wherein R is selected from OCH and N, and wherein x is 1-2, y is 3-6, and n is 2-3.

[0088] In some embodiments, the metal-containing layer reactant pulse includes providing a metal-containing layer reactant to the reaction chamber. Preferably, the metal-containing layer reactant may be selected from H2O, O3, and H2O2. Additionally or alternatively, the metal-containing layer reactant pulse may include generating a plasma in the reaction chamber. In some embodiments, the plasma may be selected from a hydrogen-containing plasma and an oxygen-containing plasma. Suitable hydrogen-containing plasmas include plasmas employing a plasma gas including at least one of H2O, H2O2, and H2. Suitable oxygen-containing plasmas include plasmas employing a plasma gas including at least one of O2, O3, H2O, and H2O2. It should be understood that some plasmas, such as plasmas employing a plasma gas including at least one of H2O and H2O2, can be classified as both oxygen-containing plasmas and hydrogen-containing plasmas.

[0089] In some embodiments, the metal-containing layer reactant includes at least one of oxygen and nitrogen. In some embodiments, the metal-containing layer reactant includes both nitrogen and oxygen. Exemplary metal-containing layer reactants include oxygen (O), water (H0), ozone (O), hydrogen peroxide (H0), NH, diazene (NH), and the like.

[0090] In some embodiments, the metal-containing layer is deposited by a thermal ALD or thermal CVD process. In some embodiments, the metal-containing layer reactant is selected from H2O, O3, and H2O2.

[0091] In some embodiments, the metal-containing layer is deposited by a plasma-enhanced ALD method or a plasma-pulsed CVD method. Therefore, in some embodiments, depositing the metal-containing layer can include exposing the substrate to a plasma pulse. Preferably, the plasma pulse can include generating a plasma in the reaction chamber. The plasma can be selected from a plasma employing a plasma gas containing H, a plasma gas containing H and He, a plasma gas containing H and Ar, a plasma gas containing Ar, and a plasma gas containing O. Therefore, a thin metal-containing layer with excellent uniformity can be formed.

[0092] In some embodiments, the metal-containing layer includes carbon. For example, the metal-containing layer can include at least 5 atomic % and up to 30 atomic % carbon. In some cases, the concentration of carbon within the metal-containing layer can vary with height of the metal-containing layer; for example, the concentration of carbon near the top surface of the metal-containing layer (e.g., in the top 1-2 nm) can be greater than the concentration of carbon below or in the bulk of the metal-containing layer. In such embodiments, the concentration of carbon at the top surface of the metal-containing layer can be greater by at least 10 atomic % and up to 50 atomic %.

[0093] In some embodiments, a carbon precursor is provided to the reaction chamber during the process of forming the metal-containing layer. The carbon precursor can include any suitable organic compound, such as a compound containing carbon and oxygen. In some cases, the carbon precursor can also include nitrogen. The carbon precursor can be selected to react with, for example, the -OH terminated surface of a metal oxide and / or the -NH2 terminated surface of a metal nitride. In some embodiments, the carbon precursor includes one or more of an organic carboxylic acid anhydride, toluene, diethylene glycol, triethylene glycol, acetaldehyde, and an organosilicon compound (such as silanes and siloxanes). Examples of suitable carbon precursors include one or more of an organic compound, such as an acid anhydride (e.g., acetic anhydride), toluene, diethylene glycol, triethylene glycol, acetaldehyde, and an organosilicon compound (such as silanes and siloxanes). Exemplary organosilicon compounds include (n,n-dimethylamino)trimethylsilane, trimethoxy(octadecyl)silane, hexamethyldisilazane, trimethoxy(3,3,3-trifluoropropyl)silane, trimethoxyphenylsilane, trichloro(3,3,3-trifluoropropyl)silane, and hexamethyldisilazane. In some embodiments, the carbon precursor comprises an organosilicon compound selected from the group consisting of (n,n-dimethylamino)trimethylsilane, trimethoxy(octadecyl)silane, trimethoxyphenylsilane, trichloro(3,3,3-trifluoropropyl)silane, and hexamethyldisilazane.

[0094] In some embodiments, the metal-containing precursor is titanium(IV) isopropoxide.

[0095] In some embodiments, the metal-containing layer comprises Hf, and the metal-containing layer is deposited using a precursor selected from tetrakis(ethylmethylamido)hafnium, dimethylbis(cyclopentadienyl)hafnium, and hafnium(IV) tert-butoxide.

[0096] In some embodiments, the metal-containing layer comprises Ta, and the metal-containing layer is deposited using a precursor selected from pentakis(dimethylamino)tantalum, tantalum(V) ethoxide, tris(diethylamido)(tert-butylimido)tantalum, tris(ethylmethylamido)(tert-butylimido)tantalum, tantalum tetraethoxydimethylaminoethoxide, and tert-butylimidotris(diethylamido)tantalum.

[0097] In some embodiments, the metal-containing layer is formed at a temperature of at least 70°C and up to 300°C, or at a temperature of at least 70°C and up to 120°C, or at a temperature of at least 120°C and up to 170°C, or at least 170°C and up to 220°C, or at least 220°C and up to 300°C.

[0098] In some embodiments, forming the metal-containing layer includes forming a lower metal-containing layer portion and an upper metal-containing layer portion.

[0099] In some embodiments, the lower metal-containing layer portion is formed using a metal halide precursor.

[0100] In some embodiments, the lower metal-containing layer portion has the general formula M[R(C x H y ) n ]4, wherein M is selected from Ti, Ta, Hf, Zn, and Zr; wherein R is selected from OCH and N; wherein x is 1-2; wherein y is 3-6; and wherein n is 2-3.

[0101] In some embodiments, the upper metal-containing layer portion has the general formula M[R(C x H y ) n ]4, wherein M is selected from Ti, Ta, Hf, Zn, and Zr; wherein R is selected from OCH and N; wherein x is 1-2; wherein y is 3-6; and wherein n is 2-3.

[0102] In some embodiments, the upper metal-containing layer portion is formed using a plasma-enhanced atomic layer deposition process or a plasma-enhanced chemical vapor deposition process in which a noble gas is used as the plasma gas. In some embodiments, the noble gas comprises Ar.

[0103] In some embodiments, the upper metal-containing layer portion comprises silicon, oxide, and carbon, the upper metal-containing layer portion having a thickness of at least 0.1 nm to at most 2.0 nm, and the upper metal-containing layer portion is formed using a cyclic deposition process including multiple cycles, each cycle including a precursor pulse and a reactant pulse. In some embodiments, the precursor pulse includes providing an organosilicon precursor to the reaction chamber, and the reactant pulse includes providing an oxygen-containing reactant selected from O2, HO, O2, and HO2 to the reaction chamber. Optionally, the precursor pulse and the reactant pulse are separated by a purge. Optionally, subsequent cycles are separated by a purge.

[0104] In some embodiments, forming the metal-containing layer comprises a plasma-enhanced atomic layer deposition (PEALD) process including one or more cycles including providing a substrate to a reaction chamber, exposing the substrate to one or more precursors, purging excess precursors from the reaction chamber, exposing the substrate to a noble gas plasma (a noble gas plasma containing reactive species), and purging excess reactive species from the reaction chamber.

[0105] In some embodiments, the lower metal-containing layer portion has a layered structure comprising alternating silicon-containing and metal-containing lamellae. Such a structure can be obtained, for example, by employing a cyclic deposition process comprising a plurality of supercycles. A supercycle comprises one or more subsequent silicon subcycles and one or more subsequent metal subcycles. A silicon subcycle comprises providing a precursor pulse in which a silicon precursor is provided to the reaction chamber and a reactant pulse in which a suitable reactant is provided to the reaction chamber. A metal subcycle comprises providing a precursor pulse in which a metal precursor is provided to the reaction chamber and a reactant pulse in which a suitable reactant is provided to the reaction chamber. Optionally, one or more of the reactant pulses comprises generating a plasma in the reaction chamber. In some embodiments, the silicon precursor is selected from aminosilanes, alkylsilanes, alkoxysilanes, and silicon halides. In some embodiments, the metal precursor is a compound represented by the general formula M[R(C x H y ) n ]4, wherein M is selected from Ti, Ta, Hf, Zn, and Zr, wherein R is selected from OCH and N, wherein x is 1-2, wherein y is 3-6, and wherein n is 2-3.

[0106] In some embodiments, the method further includes depositing a photoresist layer on the metal-containing layer. Methods for such deposition of a photoresist layer are known in the art. For example, the photoresist can be deposited using spin-on coating or using a vapor deposition process. The photoresist layer can be or include a positive or negative tone extreme ultraviolet (EUV) lithography photoresist.

[0107] Further described herein is a system. The system comprises a reaction chamber and a gas injection system fluidly connected to the reaction chamber. The system further comprises a first gas source for introducing a precursor and optionally a carrier gas into the reaction chamber. The system further comprises a second gas source for introducing a mixture of one or more additional gases into the reaction chamber. The system further comprises an exhaust and a controller. The controller is configured to control the flow of gas into the gas injection system. The controller is further configured to cause the system to perform a method as described herein.

[0108] FIG. 1 illustrates several embodiments of a structure (100) formed by a method as described herein. In particular, FIG. 1 includes three panels: panel a), panel b), and panel c). Panel a) illustrates a structure (100) comprising a surface layer (120) on a substrate (110). A barrier layer (130) is formed on the surface layer (120). In some embodiments, the barrier layer (130) comprises a plasma-modified surface layer. Additionally or alternatively, the barrier layer (130) can comprise an intermediate layer (132). A metal-containing layer (140) overlies the barrier layer (130). Panel b) of FIG. 1 illustrates another structure (100). This is similar to the structure (100) shown in panel a), except that in panel b), the barrier layer (130) includes a plasma-modified surface layer (131) and an intermediate layer (132) on top of the plasma-modified surface layer (131). Panel c) of Figure 1 shows another structure (100), which is similar to the structure (100) shown in panel a), except that in panel c), the barrier layer (130) includes an intermediate layer (132) and a plasma-modified intermediate layer (133) on top of the intermediate layer (132).

[0109] FIG. 2 illustrates one embodiment of a method (200) for forming a structure as described herein. The method (200) includes providing a substrate to a reaction chamber (210). The substrate can include one or more layers (which can include one or more material layers) to be etched. By way of example, the substrate can include a deposited oxide, a native oxide, or a bulk semiconductor to be etched. Optionally, the substrate can include several layers underlying the material layer(s) to be etched. The substrate further includes a surface layer comprising amorphous carbon. The method further includes forming a barrier layer (220) on the surface layer. The method then includes depositing a metal-containing layer on the substrate (230). It should be understood that the metal-containing layer includes oxygen and a metal. Optionally, the method further includes depositing a photoresist on the metal-containing layer (240). According to an exemplary embodiment of the method (200), the metal-containing layer can be formed using a cyclic deposition process, such as an ALD process. The cyclic deposition process can include the use of activated species (e.g., species formed from one or more of the precursor(s), reactant(s), and / or inert gas(es)) formed using one or more of a direct current plasma and a remote plasma. Alternatively, the metal-containing layer can be deposited by a thermal cyclic deposition process. The use of a cyclic deposition process can be desirable because it allows for the formation of a metal-containing layer of a desired thickness (e.g., less than 10 nm or about 5 nm or less, with improved thickness uniformity) both within a substrate and from substrate to substrate. The use of a plasma-enhanced process can be desirable because it allows for the deposition of metal-containing layer materials at relatively low temperatures. According to embodiments of the present disclosure, the temperature within the reaction chamber can be at least 100°C and up to 500°C during at least one of the steps of forming the barrier layer (220) and depositing the underlayer (230).In some embodiments, the pressure in the reaction chamber during at least one of forming the barrier layer (220) and depositing the metal-containing layer (230) can be at least 1 Torr and up to 100 Torr, or at least 3 Torr and up to 50 Torr, or at least 5 Torr and up to 20 Torr.

[0110] 3 illustrates one embodiment of a method (300) for depositing a barrier layer as described herein. This embodiment includes a step (310) of subjecting a substrate to a nitrogen-containing plasma. Thus, a barrier layer can be formed. Optionally, the method (300) further includes a step (330) of depositing an intermediate layer. Optionally, the step (310) of subjecting the substrate to the nitrogen-containing plasma and the step (330) of depositing the intermediate layer are separated by a purge (320). Optionally, the step (330) of depositing the intermediate layer is followed by another purge (340).

[0111] 4 illustrates one embodiment of a method (400) for depositing a barrier layer as described herein. This embodiment includes a step (410) of depositing an intermediate layer on a substrate. Thus, a barrier layer can be formed. Optionally, the method (400) further includes a step (430) of subjecting the substrate to a nitrogen-containing plasma. Optionally, the step (410) of depositing the intermediate layer and the step (430) of subjecting the substrate to the nitrogen-containing plasma are separated by a purge (420). As a result, a plasma-modified intermediate layer is formed. Optionally, the step (430) of subjecting the substrate to the nitrogen-containing plasma is followed by another purge (440).

[0112] FIG. 5 illustrates one embodiment of a method (500) for depositing an intermediate layer as described herein. This embodiment includes providing a precursor to the reaction chamber during a precursor pulse (510) and providing a reactant to the reaction chamber during a reactant pulse (530). The precursor pulse (510) and the reactant pulse (530) together form a cycle. This cycle can be repeated one or more times (550). Optionally, the precursor pulse (510) and the reactant pulse (530) are separated by an intra-cycle purge (520). Optionally, subsequent cycles are separated by an inter-cycle purge (540). Thus, an intermediate layer can be formed on a substrate located in the reaction chamber. With each cycle, the thickness of the intermediate layer increases. When the intermediate layer reaches a predetermined thickness, the method (500) ends. Optionally, the intermediate layer can then be subjected to a plasma treatment. Additionally or alternatively, a metal-containing layer can be deposited on the intermediate layer.

[0113] FIG. 6 shows experimental results (particularly transmission electron micrographs) of structures used employing a method according to one embodiment of the present disclosure. In particular, micrographs a and b, labeled "pristine," show a silicon substrate (610) with an amorphous carbon layer (620) deposited thereon. The middle micrographs c and d, labeled "as deposited," show the same substrate with a metal-containing layer (630) deposited on the amorphous carbon layer (620). In micrograph d, a barrier layer (not visible) is positioned between the amorphous carbon layer (620) and the metal-containing layer (630). In micrograph c, the metal-containing layer (630) is deposited directly on the amorphous carbon layer (620), and no barrier layer is present. Micrograph e shows the structure of micrograph c after exposure to oxygen plasma. The resulting structure is rough. Micrograph f shows the structure of micrograph d after exposure to oxygen plasma. The resulting structure is smooth and less damaged than the structure shown in micrograph e. Therefore, the barrier layer advantageously provides a metal-containing layer with better resistance to oxygen plasma. In this example, the barrier layer was specifically formed by first depositing an intermediate layer on an amorphous carbon layer. The intermediate layer was specifically deposited using multiple cycles of precursor pulse-purge-plasma exposure-purge sequence. Depending on the desired layer thickness, any number of cycles can be used, for example, at least 1 cycle to up to 1000 cycles, or at least 2 cycles to up to 500 cycles, or at least 5 cycles to up to 200 cycles, or at least 10 cycles to up to 100 cycles, or at least 20 cycles to up to 50 cycles. In one embodiment according to this example, 150 cycles were used. During the precursor pulse, a metal precursor was provided to the reaction chamber. In one embodiment according to this example, a titanium precursor was used. Suitable titanium precursors include titanium alkoxides, such as C1-C4 titanium alkoxides. More specifically, in one embodiment according to this example, titanium(IV) isopropoxide was used. The precursor pulse lasted 0.7 seconds, and the post-precursor purge lasted 0.4 seconds. During the plasma exposure step, a noble gas plasma can be used, and in one embodiment according to this example, an argon plasma was used.Preferably at least 10 mW / cm. 2 ~Maximum 50mW / cm 2 In one embodiment according to this example, a plasma power density of 18 mW / cm can be used. 2 A plasma power density of 100 Pa to 10,000 Pa was used. In some embodiments, the reaction chamber is maintained at a pressure of at least 100 Pa to 10,000 Pa, or at least 200 Pa to 5000 Pa, or at least 500 Pa to 2000 Pa. In one embodiment according to this example, the reaction chamber was maintained at a pressure of 900 Pa.

[0114] FIG. 7 shows experimental results (particularly transmission electron micrographs) of a structure used employing a method according to one embodiment of the present disclosure. The structure of FIG. 7 is similar to the structure shown in FIG. 6. In particular, micrographs a and b, labeled "pristine," show a silicon substrate (710) with an amorphous carbon layer (720) deposited thereon. The amorphous carbon layer (720) in FIG. 7 is more porous than the amorphous carbon layer (620) in FIG. 6. The middle micrographs c and d, labeled "as deposited," show the same substrate with a metal-containing layer (730) deposited on the amorphous carbon layer (720). In micrograph d, a barrier layer (not visible) is positioned between the amorphous carbon layer (720) and the metal-containing layer (730). In micrograph c, the metal-containing layer (730) is deposited directly on the amorphous carbon layer (720), and no barrier layer is present. The barrier layer and metal-containing layer (730) in Figure 7 were deposited using the same method as the barrier layer and metal-containing layer (630) in Figure 6. Micrograph e shows the structure in micrograph c after exposure to oxygen plasma. Micrograph f shows the structure in micrograph d after exposure to oxygen plasma. Figure 7 shows that even porous amorphous carbon layers can be efficiently protected during exposure to oxygen plasma by a barrier layer as disclosed herein.

[0115] FIG. 8 shows experimental results (particularly transmission electron micrographs) of structures used employing a method according to one embodiment of the present disclosure. In particular, micrographs a and b, labeled "pristine," show a silicon substrate (810) with an amorphous carbon layer (820) deposited thereon. The middle micrographs c and d, labeled "as deposited," show the same substrate with a metal-containing layer (830) deposited on the amorphous carbon layer (820). In micrograph d, a barrier layer (not visible) is positioned between the amorphous carbon layer (820) and the metal-containing layer (830). In micrograph c, the metal-containing layer (830) is deposited directly on the amorphous carbon layer (820), and no barrier layer is present. Micrograph e shows the structure in micrograph c after exposure to oxygen plasma. The resulting structure is rough. Micrograph f shows the structure in micrograph d after exposure to oxygen plasma. The resulting structure is smooth and less damaged than the structure shown in micrograph e. Therefore, the barrier layer advantageously results in a metal-containing layer that is more resistant to oxygen plasma. In this example, the barrier layer was specifically formed by exposing the amorphous carbon layer to a capacitive, direct current, and sustained (i.e., non-pulsed) nitrogen plasma, in which N2 was used as the plasma gas. In some embodiments, the amorphous carbon layer can be exposed to the nitrogen plasma for at least 1 second and up to 10 seconds. In one embodiment according to this example, the amorphous carbon layer was exposed to the nitrogen plasma for 3 seconds. Preferably, the reaction chamber in which the amorphous carbon layer is exposed to the nitrogen plasma can be purged after the plasma exposure, for example, for a duration of at least 0.01 seconds and up to 1 second. In one embodiment according to this example, the reaction chamber is purged for a duration of 0.1 seconds. The nitrogen plasma has an intensity of at least 50 mW / cm. 2 ~Max 200mW / cm 2 In one embodiment according to this example, the plasma power density is 106 mW / cm. 2A plasma power density of 100 Pa to 10,000 Pa was used. In some embodiments, the reaction chamber is maintained at a pressure of at least 100 Pa to 10,000 Pa, or at least 200 Pa to 5000 Pa, or at least 300 Pa to 2000 Pa. In one embodiment according to this example, the reaction chamber was maintained at a pressure of 400 Pa.

[0116] FIG. 9 shows experimental results (particularly transmission electron micrographs) of a structure used employing a method according to one embodiment of the present disclosure. In particular, micrographs a and b, labeled "pristine," show a silicon substrate (910) with an amorphous carbon layer (920) deposited thereon. The amorphous carbon layer (920) in FIG. 9 is more porous than the amorphous carbon layer (820) in FIG. 8. The middle micrographs c and d, labeled "as-deposited," show the same substrate with a metal-containing layer (930) deposited on the amorphous carbon layer (920). In micrograph d, a barrier layer (not visible) is positioned between the amorphous carbon layer (920) and the metal-containing layer (930). In micrograph c, the metal-containing layer (930) is deposited directly on the amorphous carbon layer (920), and no barrier layer is present. The barrier layer and metal-containing layer (930) in Figure 9 were deposited using the same method as the barrier layer and metal-containing layer (830) in Figure 8. Micrograph e shows the structure in micrograph c after exposure to oxygen plasma. Micrograph f shows the structure in micrograph d after exposure to oxygen plasma. Figure 9 shows that even porous amorphous carbon layers can be effectively protected during exposure to oxygen plasma by a barrier layer as disclosed herein, although, as shown in Figure 8, the protection is clearly not as effective as when a less porous amorphous carbon layer is used.

[0117] 10 illustrates a structure (1000) according to an exemplary embodiment of the present disclosure. The structure (1000) can be formed using the methods as disclosed herein. The structure (1000) includes a substrate (1010), a patternable layer (1020), a surface layer (1030), a barrier layer (1040), a metal-containing layer (1050), and a photoresist layer (1060).

[0118] The substrate (1010) can include a substrate as described herein. By way of example, the substrate (1010) can include a bulk material such as silicon (e.g., single crystal silicon), a semiconductor substrate such as other Group IV semiconductor materials, Group III-V semiconductor materials, and / or Group II-VI semiconductor materials, and can include one or more layers (e.g., patterned stacks) overlying the bulk material. Additionally, as described above, the substrate (1010) can include various topologies (such as depressions, lines, and the like) formed within or on at least a portion of the layers of the substrate.

[0119] The patternable layer (1020) can be patterned and etched using the surface layer (1030), barrier layer (1040), metal-containing layer (1050), and photoresist layer (1060) as described herein. Exemplary materials suitable for the patternable layer (1020) include, for example, an oxide or nitride (e.g., an oxide or nitride of silicon), another Group IV element, or a transition metal.

[0120] Suitable surface layers (1030), barrier layers (1040), metal-containing layers (1050), and photoresist layers (1060) are described in detail elsewhere herein.

[0121] In some embodiments, the metal-containing layer (1050) can include one or more of a metal oxide, a metal nitride, and a metal oxynitride. In some embodiments, the metal-containing layer (1050) can include added carbon. For example, the metal-containing layer (1050) can have a uniform carbon concentration or a carbon concentration gradient. The metal-containing layer (1050) has a thickness that depends on the composition of the patternable layer (1020), the thickness of the patternable layer (1050), the particular photoresist used in the photoresist layer (1060), and the like. Suitable metal-containing layer thicknesses include thicknesses of less than 5 nm, less than 3 nm, or less than 2 nm. Optionally, the surface of the metal-containing layer (1050) can be treated, for example, by exposing the substrate to a plasma after deposition of the metal-containing layer (1050). Therefore, a suitable surface termination can be achieved, which can promote adhesion with the photoresist layer (1060) in some embodiments.

[0122] FIG. 11 illustrates an exemplary process flow (1100) for depositing a metal-containing layer or portion thereof by plasma-enhanced chemical vapor deposition. In the process (1100), a substrate in a reaction chamber is exposed to one or more precursors (1110). Excess precursors may then be purged from the reaction chamber (1120). The substrate may then be subjected to a plasma (1130). For example, a noble gas plasma, such as He, Ne, Ar, or Kr, may be used to produce an upper metal-containing layer portion with good adhesion properties. After the plasma step, excess reactive species, such as ions and radicals, are suitably purged from the reaction chamber (1140). The aforementioned steps form one cycle. These cycles may be repeated any number of times (1150) to deposit a metal-containing layer or portion thereof having a desired thickness.

[0123] In some embodiments, the metal-containing layer, or a portion thereof, is deposited using a thermal atomic layer deposition process, as opposed to plasma-enhanced atomic layer deposition. In such embodiments, it may be particularly advantageous to subject the metal-containing layer to a plasma, such as a noble gas plasma, after the metal-containing layer is deposited. Such post-treatment may advantageously densify the metal-containing layer.

[0124] FIG. 12 illustrates an exemplary embodiment of a method (1200) as described herein. In particular, the method (1200) of FIG. 12 includes a step (1210) of exposing a substrate to radicals. Suitable radicals include those described herein. The method (1200) of FIG. 12 then includes a step (1220) of exposing the substrate to a precursor. Preferably, the steps of exposing the substrate to radicals and exposing the substrate to a precursor (1210, 1220) can be separated by a purge. Suitable precursors include those described herein. Optionally, the steps of exposing the substrate to radicals and exposing the substrate to a precursor (1210, 1220) can be repeated one or more times (1250). Preferably, the resulting cycles can be separated by a purge. Thus, a barrier layer can be formed on the substrate. Optionally, the method further includes forming an additional layer on the substrate (1230). Methods such as that of FIG. 12 may advantageously allow for the formation of additional layers (1230) with easier nucleation on certain substrates, such as substrates containing a CH-terminated amorphous carbon surface layer.

[0125] In some embodiments, the radicals are selected from oxygen radicals and nitrogen radicals. Preferably, oxygen radicals can be generated using O2 remote plasma. Preferably, nitrogen radicals can be generated using N2 or NH3 remote plasma. It should be understood that the terms O2 remote plasma and N2 remote plasma refer to remote plasmas employing plasma gases containing O2 or N2, respectively. The plasma gas can preferably contain other gases, such as noble gases. Suitable noble gases include He, Ne, Ar, Kr, and Xe.

[0126] In some embodiments, the precursor comprises a metal precursor and a silicon precursor. Suitable silicon precursors include alkylaminosilanes such as N-(diethylaminosilyl)-N-ethylethanamine. Suitable metal precursors include compounds containing alkylamine ligands such as tetrakis(dimethylamido)titanium. Other suitable metal precursors include compounds containing alkoxide ligands such as titanium isopropoxide.

[0127] In some embodiments, the above-described cyclic process including alternating radical and precursor exposure can be employed to form the entire barrier layer. Alternatively, one or more cycles including alternating radical and precursor exposure can be followed by the formation of additional layers using a different deposition process. Exemplary additional deposition processes include plasma-enhanced deposition processes, such as plasma-enhanced atomic layer deposition processes, that employ alternating direct current plasma and precursor exposure. In other words, the additional deposition can include one or more cycles including a direct current plasma pulse and a precursor pulse. The direct current plasma pulse includes exposing the substrate to a direct current plasma, such as a direct current oxygen plasma or a direct current nitrogen plasma. The precursor pulse includes exposing the substrate to a precursor, such as a silicon precursor or a metal precursor. A suitable oxygen plasma includes an O2 plasma. A suitable nitrogen plasma includes an N2 plasma.

[0128] In some embodiments, the above-described cyclic process including alternating radicals and precursors can be employed until a barrier layer having a thickness of less than 2 nm (e.g., at least 0.3 nm and up to 1.5 nm) is formed, and additional layers are formed using alternating DC plasma and precursor pulses. Thus, the underlying substrate can be suitably protected from ion bombardment from the DC plasma by the barrier layer formed using the radical-enhanced deposition process.

[0129] The exemplary embodiments of the present disclosure described above do not limit the scope of the present invention, as these embodiments are merely examples of embodiments of the present invention. Any equivalent embodiments are intended to be within the scope of the present invention. Indeed, various modifications of the present disclosure in addition to the embodiments shown and described herein may become apparent to those skilled in the art from the description, such as alternative useful combinations of the described elements. Such modifications and embodiments are also intended to be encompassed within the scope of the appended claims.

Claims

1. 1. A method of forming a structure comprising, in order: - providing a substrate in a reaction chamber, said substrate comprising a semiconductor and a surface layer, said surface layer comprising amorphous carbon; - forming a barrier layer on said surface layer; - depositing a metal-containing layer on the substrate, the metal-containing layer comprising oxygen and a metal; - depositing a photoresist layer on said metal-containing layer.

2. The method of claim 1 , wherein forming the barrier layer on the surface layer comprises exposing the surface layer to a nitrogen-containing plasma, thus forming a plasma-modified surface layer.

3. The method of claim 2 , wherein forming the barrier layer on the surface layer comprises depositing an intermediate layer on the plasma-modified surface layer.

4. The method of any one of claims 1 to 3, wherein forming the barrier layer on the surface layer comprises depositing an intermediate layer on the surface layer.

5. 5. The method of claim 4, wherein forming the barrier layer on the surface layer further comprises exposing the intermediate layer to a nitrogen-containing plasma, thus forming a plasma-modified intermediate layer.

6. 6. The method of any one of claims 3 to 5, wherein depositing the intermediate layer comprises a cyclical process comprising a plurality of subsequent cycles, one cycle comprising an intermediate layer precursor pulse and an intermediate layer reactant pulse, the intermediate layer precursor pulse comprising providing an intermediate layer precursor to the reaction chamber, and the intermediate layer reactant pulse comprising providing an intermediate layer reactant to the reaction chamber.

7. The method of claim 6 , wherein the intermediate layer precursor is selected from the list consisting of a silicon precursor, a titanium precursor, and a tantalum precursor.

8. 8. The method of claim 6 or claim 7, wherein the interlayer reactant is an oxygen reactant.

9. The oxygen reactant is O ２ , O ３ , H ２ O, H ２ O ２ , N ２ O, NO, CO ２ , CO, and NO ２ 9. The method of claim 8, comprising a gaseous species selected from:

10. 10. The method of any one of claims 6 to 9, wherein neither the step of providing an intermediate layer precursor to the reaction chamber nor the step of providing an intermediate layer reactant to the reaction chamber comprises generating a plasma in the reaction chamber.

11. The method according to any one of claims 4 to 10, wherein the intermediate layer has a thickness of 3 nm or less.

12. The method of claim 1 , wherein the photoresist layer comprises an EUV photoresist.

13. 13. The method of any one of claims 1 to 12, wherein depositing a metal-containing layer on the substrate comprises a cyclic deposition process comprising a plurality of subsequent cycles, one cycle comprising a metal-containing layer precursor pulse and a metal-containing layer reactant pulse.

14. The method of claim 13 , wherein at least one of the metal-containing layer precursor pulse and the metal-containing layer reactant pulse is preceded by a purge.

15. The metal-containing layer precursor pulse comprises providing a metal-containing precursor to the reaction chamber, the metal-containing precursor having the general formula M[R(C ｘ H ｙ ) ｎ ] ４ wherein M is selected from Ti, Ta, Hf, Zn, and Zr; R is selected from OCH and N; where x is 1 to 2; where y is 3 to 6; and where n is 2 to 3.

16. The metal-containing layer reactant pulse includes providing a metal-containing layer reactant to the reaction chamber, the metal-containing layer reactant comprising H ２ O, O ３ , and H ２ O ２ The method according to any one of claims 13 to 15, wherein the compound is selected from the group consisting of:

17. 16. The method of any one of claims 13 to 15, wherein the metal-containing layer reactant pulse comprises generating a plasma in the reaction chamber, the plasma being selected from a hydrogen-containing plasma and an oxygen-containing plasma.

18. The method of any one of claims 1 to 17, wherein forming the barrier layer on the surface layer comprises exposing the substrate to radicals.

19. 1. A system comprising: a reaction chamber, a gas injection system fluidly connected to the reaction chamber; a first gas source for introducing precursor and carrier gases into said reaction chamber; a second gas source for introducing a mixture of one or more additional gases into the reaction chamber; - an exhaust port; a controller, A system, wherein the controller is configured to control gas flow into the gas injection system and to cause the system to perform the method of any one of claims 1 to 18.

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