Atomic layer etching of metals using coreactants as halogenating agents.

Abstract

The disclosed and claimed invention relates to thermal atomic layer etching (ALE) processing of metals and their alloys (e.g., cobalt and cobalt alloys) using thionyl chloride (SOCl2) or a combination of thionyl chloride and pyridine.

Description

[Technical Field]

[0001] The disclosed and claimed invention relates to thermal ALE processing of metals and their alloys (e.g., cobalt and cobalt alloys) using thionyl chloride (SOCl2) or a combination of thionyl chloride and pyridine. [Background technology]

[0002] Feature shrinkage in the semiconductor industry is a major factor behind the continuous improvement in device performance. This trend is expected to continue for at least several more generations of computer chips. Continuing this trend requires the successful resolution of several technological challenges.

[0003] Atomic layer deposition (ALD) is a technique finding increasing application in the semiconductor industry and is currently the deposition method that offers the best control over the amount of material deposited. In ALD, atomic layers are deposited on all surfaces exposed to a vapor-phase precursor, with the layer being at most one atomic layer thick. By sequentially exposing these surfaces to two different precursors, a layer of material of the desired thickness is deposited. A prototypical example of such a method is the deposition of aluminum oxide (Al2O3) from trimethylaluminum (TMA, Al(CH3)3) and water (H2O), where methane (CH4) is desorbed from these two reactive species. Coating of thin and narrow vias and other high-aspect-ratio features has been demonstrated many times in the literature by ALD.

[0004] Atomic layer etching (ALE or ALEt) can be viewed as layer-by-layer removal of material, whereas ALD is layer-by-layer addition of material. In ALE, an atomic layer is removed from any surface exposed to a vapor-phase precursor, ideally at most one atomic layer thick. ALE is performed by sequentially exposing a surface to at least two different precursors: a first precursor activates a layer of surface atoms, and a second precursor promotes the sublimation of this activated layer of atoms; sometimes a third precursor and other additional process steps are used to regenerate the surface to conditions where the first precursor becomes active.

[0005] Careful removal of material is critical for fabricating transistor and memory devices with sub-10 nm geometries. In this regard, ALE enables precise material removal by using sequential and self-limiting half-reaction steps. The key half-reactions during ALE include an "activation" step, often using halogenated reagents to modify the surface to be etched, and a subsequent "removal" step, which vaporizes the modified surface layer. Plasma-based ALE uses plasma activation to promote anisotropic etching of different materials, including Si, Si3N4, SiO2, and Al2O3. See, for example, Carver et al., ECS J. Solid State Sci. Technol., 4, N5005 (2015) (Non-Patent Document 1); Kanarik et al., J. Phys. Chem. Lett., 9, 4814 (2018) (Non-Patent Document 2); and Kanarik et al., J. Vac. Sci. Technol. A Vacuum, Surfaces, Film., 33, 020802 (2015) (Non-Patent Document 3). For example, Si ALE can be prepared by the reaction of SiCl xThe process proceeds via Cl2 plasma exposure to form a surface passivation layer, which is then removed by Ar+ bombardment. See Kanarik et al., J. Vac. Sci. Technol. A Vacuum, Surfaces, Film., 33, 020802 (2015). However, even with careful control of bias power during ion bombardment, repeated exposure to powerful chemical species can alter the surface composition of or damage the device structure. See Gu et al., IEEE Electron Device Lett., 15, 48 (1994). In thermal-based ALE, a thermally activated reaction enables isotropic etching of a variety of materials, including Al2O3, HfO2, ZrO2, TiO2, TiN, SiO2, and Si3N4. See, for example, Abdulagatov et al., JVSTA, 38, 1 (2020) (Non-Patent Document 5); Lee et al., ECS J.Solid State Sci.Technol., 4, N5013 (2015) (Non-Patent Document 6); Lemaire et al., Chem.Mater., 29, 6653 (2017) (Non-Patent Document 7); Abdulagatov et al., Chem.Mater. 30, acs.chemmater.8b02745 (2018) (Non-Patent Document 8); Lee et al., J.Vac.Sci.Technol.A, 36, 061504 (2018) (Non-Patent Document 9); and Lee et al., Chem.Mater., 29, 8202 (2017) (Non-Patent Document 10). Thermal ALE methods for compound materials such as metal oxides generally involve surface fluorination with HF followed by removal of the surface fluoride layer via a ligand exchange reaction with Sn(acac)2, TMA, DMAC, or BCl3.See, for example, Lemaire et al., Chem. Mater., 29, 6653 (2017) (Non-Patent Document 7); Lee et al., J. Vac. Sci. Technol. A, 36, 061504 (2018) (Non-Patent Document 9); Lee et al., Chem. Mater., 27, 3648 (2015) (Non-Patent Document 11); George et al., ACS Nano, 10, 4889 (2016) (Non-Patent Document 12); and Lee et al., Chem. Mater., 28, 7657 (2016) (Non-Patent Document 13).

[0006] Although Cl2 and HF are widely used in ALE processes, their gaseous state and / or highly corrosive and toxic properties make them difficult to handle safely. Additionally, because HF is a highly polar molecule, it tends to adhere to the inner walls of the reactor chamber during processing, requiring long purging times to ensure its removal. See, for example, Xie et al., J. Vac. Sci. Technol. A, 022605 (2020) (Non-Patent Document 14). Therefore, an ALE method that does not rely on HF would be highly advantageous for implementation.

[0007] Cobalt (Co) and its alloys are considered promising materials for use in magnetic random access memory (MRAM) devices and in the middle-of-line (MOL) and back-end-of-line (BEOL) processing of semiconductor logic and memory devices. However, to the best of the inventors' knowledge, there are currently only limited papers describing the thermal ALE of Co. Konh et al. and Wang et al. reported that CoCl was chlorinated using Cl2(g) to produce CoCl. x (s) was then evaporated with hexafluoroacetylacetone (Hhfac) to give Co(Hfac) as the volatile product. x Cl yreported a thermal ALE mechanism involving the formation of a gold complex. See Konh et al., J. Vac. Sci. Technol. A 021004 (2019) (Non-Patent Document 15); Wang et al., JVSTA 38 (2020) 022611 (Non-Patent Document 16). Lin et al. demonstrated the dissolution of gold in a liquid mixture consisting of SOCl2 and pyridine in a 3:1 volume ratio, which is also effective in dissolving silver, gold, palladium, copper, nickel, and iron. Specifically, Lin et al. found that the dissolution of gold was due to pyridine activating SOCl2 and promoting the conversion of gold to gold chloride, whereas SOCl2 or pyridine alone did not result in any dissolution. See Lin et al., Angew. Chemie Int. Ed., No. 49, 7929-7932. https: / / doi.org / 10.1002 / anie.201001244(2010) (Non-Patent Document 17).

[0008] In the disclosed and claimed invention, either thionyl chloride or a combination of thionyl chloride (SOCl) and pyridine is used as the surface chlorination reagent for thermal ALE of metals. For example, in some embodiments, cobalt was successfully etched using thionyl chloride (SOCl) and pyridine as the chlorinating agent and hexafluoroacetylacetone (Hhfac) as the vaporizing agent. In contrast, other known surface chlorinating agents, such as BCl, TiCl, AlCl, or Al(CH)Cl (DMAC), have not shown comparable success. [Prior art documents] [Non-patent literature]

[0009] [Non-Patent Document 1] Carver et al.,ECS J.Solid State Sci.Technol.,4,N5005 (2015) [Non-patent document 2] Kanarik et al.,J.Phys.Chem.Lett.,9,4814(2018) [Non-patent document 3] Kanarik et al.,J.Vac.Sci.Technol.A Vacuum,Surfaces,Film.,33,020802(2015)

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Summary of the Invention

[0010] In one embodiment, the disclosed and claimed invention relates to a method for thermal ALE processing of metals and their alloys (collectively "metals"). The method generally includes: (i) forming a chlorinated metal-containing layer on a metal surface by exposing the surface to a chlorinating agent; (ii) conducting a first purge to remove excess chlorinating agent and / or reaction products; (iii) forming volatile etch products on the metal surface by exposing the chlorinated metal-containing layer to at least one vaporizing agent; and (iv) conducting a second purge to remove the resulting volatile etch products. In yet another aspect of this embodiment, the method includes, as step (iA), forming the chlorinating agent used in step (i). In yet another aspect, the method consists essentially of steps (i), (ii), (iii), and (iv). In yet another aspect, the method consists of steps (i), (ii), (iii), and (iv). In yet another aspect, the method consists essentially of steps (iA), (i), (ii), (iii), and (iv). In yet another aspect, the method consists of steps (iA), (i), (ii), (iii), and (iv).

[0011] In one aspect of this embodiment, the disclosed and claimed invention relates to the thermal ALE processing of metals and their alloys (collectively "metals"). Suitable metals include, but are not limited to, cobalt, nickel, copper, molybdenum, ruthenium, tungsten, and alloys containing these.

[0012] In another aspect of this embodiment, in step (i), the chlorinated metal-containing layer is a compound of the formula CoCl x (s), where x is a value from about 1 to about 2.

[0013] In another aspect of this embodiment, in step (iii), the at least one vaporizing agent comprises formic acid, acetylacetone (Hacac), and / or hexafluoroacetylacetone (Hhfac).

[0014] In another aspect of this embodiment, in step (iii), the at least one vaporizing agent comprises hexafluoroacetylacetone (Hhfac).

[0015] In another aspect of this embodiment, in step (iii), the volatile etch product is a compound of the formula CoCl x Hfac y (g) wherein x is 0 or 1 and y is 1 or 2.

[0016] In yet another aspect of this embodiment, the formation of volatile etch products in step (iii) produces additional by-products. In one aspect, the additional by-products include HCl(g). In one aspect, the additional by-products include Cl(g). In one aspect, the additional by-products include SCl(g). In one aspect, the additional by-products include SO(g).

[0017] In yet another aspect of this embodiment, step (i) is carried out at a temperature between about 140°C and about 325°C.

[0018] In yet another aspect of this embodiment, step (iii) is carried out at a temperature between about 140°C and about 325°C.

[0019] In yet another aspect of this embodiment, steps (i) and (iii) are each performed at about the same temperature. In yet another aspect of this embodiment, steps (i) and (iii) are each performed at the same temperature. In yet another aspect of this embodiment, steps (i) and (iii) are each performed at different temperatures.

[0020] This summary section is not intended to identify every aspect and / or radically novel aspect of the disclosed and claimed invention. Instead, this summary provides only a preliminary description of various aspects and corresponding points of novelty over conventional and known techniques. For additional details and / or possible perspectives of the disclosed and claimed invention and aspects, reference is made to the detailed description of the invention and corresponding drawings, further described below.

[0021] The order in which the different steps described herein are presented is for clarity. In general, the steps disclosed herein may be performed in any suitable order. Additionally, although different features, techniques, arrangements, etc. described herein may each be described in different parts of the specification, it is intended that each of these concepts can be practiced independently of each other or in combination with each other, where appropriate. Thus, the disclosed and claimed invention can be embodied and viewed in many different ways.

[0022] The accompanying drawings provide a further understanding of the disclosed invention, and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosed invention, and together with the description, serve to explain the principles of the disclosed invention. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 shows the change in the delta parameter (Δ) measured at 635 nm from an in situ spectroscopic ellipsometer for a Co sample exposed to 30 subdoses of SOCl, 20 subdoses of pyridine, and 20 subdoses of SOCl-Py at 250 °C. [Figure 2] Figure 2 shows the change in the delta parameter (Δ) measured at 635 nm from in situ spectroscopic ellipsometry of a Co sample exposed to 30 subdoses of BCl3, TiCl4, AlCl3, and Al(CH3)2Cl at 250 °C. [Figure 3]Figure 3 shows XPS scans of (a) the Co 2p and (b) the Ta 4f regions for Co in the pristine state and after 2, 4, 6, and 8 etching cycles at 250°C (each etching cycle follows a 6(0.4 s) / 6(0.2 s Hhfac) exposure sequence). The Ta 4f signal is from the thin layer of tantalum nitride (TaN) on which the Co is deposited.

[0024] definition Unless otherwise stated, the following terms and descriptions used in the specification and claims have the following meanings in this application:

[0025] For purposes of the disclosed and claimed invention, the numbering convention for the periodic table groups follows the IUPAC Periodic Table of the Elements.

[0026] As used herein, the term "and / or" as used in phrases such as "A and / or B" is intended to include "A and B," "A or B," or "A" and "B."

[0027] The terms "substituent," "residue," "group," and "moiety" may be used interchangeably.

[0028] As used herein, the terms "metal-containing complex" (or more simply, "complex") and "precursor" are used interchangeably and refer to a metal-containing molecule or compound that can be used to produce a metal-containing film by a vapor deposition method such as ALD or CVD. The metal-containing complex can be deposited, adsorbed, decomposed, delivered, and / or distributed onto a substrate or surface thereof such that a metal-containing film is formed.

[0029] As used herein, the term "metal-containing film" includes not only elemental metal films, as defined in more detail below, but also films that contain one or more elements in addition to metal, such as metal oxide films, metal nitride films, metal silicide films, metal carbide films, and similar films. As used herein, the terms "elemental metal film" and "pure metal film" are used interchangeably and refer to films that consist of or essentially consist of pure metal. For example, an elemental metal film may contain 100% pure metal, or an elemental metal film may contain at least about 70%, at least about 80%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, at least about 99%, at least about 99.9%, or at least about 99.99% pure metal, along with one or more impurities. Unless the context indicates otherwise, the term "metal film" shall be interpreted to mean an elemental metal film.

[0030] As used herein, the term "vapor deposition method" refers to any type of vapor deposition technique, including, but not limited to, CVD and ALD. In various embodiments, CVD can take the form of conventional (i.e., continuous flow) CVD, liquid injection CVD, or photo-assisted CVD. CVD can also take the form of a pulsed technique, i.e., pulsed CVD. ALD is used to form metal-containing films by evaporating and / or flowing at least one metal complex disclosed herein onto a substrate surface. For conventional ALD methods, see, for example, George S. M., et al., J. Phys. Chem., 1996, 100, 13121-13131. In other embodiments, ALD can take the form of conventional (i.e., pulsed injection) ALD, liquid injection ALD, photo-assisted ALD, plasma-assisted ALD, or plasma-enhanced ALD. The term "vapor deposition" also includes various vapor deposition techniques described in Chemical Vapor Deposition: Precursors, Processes, and Applications; Jones, AC; Hitchman, ML, Eds., The Royal Society of Chemistry: Cambridge, 2009; Chapter 1, pp. 1-36 (Non-Patent Document 19).

[0031] Throughout this specification, the term atomic layer etching or ALE refers to methods including, but not limited to, the following processes: (i) sequentially introducing reactants, including SOCl or a mixture of SOCl and pyridine, and Hhfac, into a reactor, such as a single-wafer ALE reactor, a semi-batch ALD reactor, or a batch furnace ALE reactor; and (ii) exposing a substrate to reactants, including SOCl or a mixture of SOCl and pyridine, and Hhfac, by moving or rotating the substrate through different sections of the reactor, where each section is separated by an inert gas curtain (i.e., a spatial ALD / ALE reactor or a roll-to-roll ALD / ALE reactor).

[0032] As used herein, the term "feature" refers to an opening in a substrate that may be defined by one or more sidewalls, a bottom, and a top corner. In various aspects, the feature may be a via, a trench, a contact, a dual damascene, etc.

[0033] The terms "about" or "approximately," when used in connection with a measurable variable, refer to the indicated value of the variable and all values ​​of the variable that are within experimental error of the indicated value (e.g., within a 95% confidence limit of the mean) or within a percentage of the indicated value (e.g., ±10%, ±5%), whichever is greater.

[0034] The disclosed and claimed precursors are preferably substantially free of water. As used herein, "substantially free," as it relates to water, means less than 5000 ppm (by weight) as measured by proton NMR or Karl Fischer titration, preferably less than 3000 ppm as measured by proton NMR or Karl Fischer titration, more preferably less than 1000 ppm as measured by proton NMR or Karl Fischer titration, and most preferably less than 100 ppm as measured by proton NMR or Karl Fischer titration.

[0035] The disclosed and claimed precursors are Li + (Li), Na + (Na), K + (K), Mg 2+ (Mg), Ca 2+ (Ca), Al 3+ (Al), Fe 2+ (Fe), Fe 3+ (Fe), Ni 2+ (Ni), Cr 3+ It is also preferred that the precursor is substantially free of metal ions or metals, such as Li, Na, K, Mg, Ca, Al, Fe, Ni, Cr, Ti, V, Mn, Co, Ni, Cu, or Zinc (Zn), potentially present from the raw materials / reactors used to synthesize the precursor. As used herein, "substantially free" means less than 5 ppm (by weight), preferably less than 3 ppm, more preferably less than 1 ppm, and most preferably less than 0.1 ppm, as measured by ICP-MS, when referring to Li, Na, K, Mg, Ca, Al, Fe, Ni, Cr, Ti, V, Mn, Co, Ni, Cu, or Zn.

[0036] Unless otherwise specified, "alkyl" refers to a C1-C6 alkyl group that can be linear, branched (e.g., methyl, ethyl, propyl, isopropyl, tert-butyl, and the like), or cyclic (e.g., cyclohexyl, cyclopropyl, cyclopentyl, and the like). 20 The term "alkyl" refers to a hydrocarbon group, the alkyl portion of which may be substituted or unsubstituted as described below. 20The term "alkyl" refers to such a moiety having carbon atoms. For structural reasons, linear alkyls start from C1, while branched alkyls start from C3. Furthermore, moieties derived from the alkyls described below, such as alkyloxy and perfluoroalkyl, are understood to have the same carbon number range unless otherwise specified. If a different alkyl group length is specified, the above definition of alkyl is still valid in that it encompasses all types of alkyl moieties, and the above structural considerations regarding the minimum carbon number of a given type of alkyl group still apply.

[0037] Halo or halide refers to a halogen, F, Cl, Br, or I, attached to an organic moiety by one bond. In some embodiments, the halogen is F. In other embodiments, the halogen is Cl.

[0038] Alkyl halides are fully or partially halogenated C1-C 20 refers to alkyl.

[0039] Perfluoroalkyl refers to a linear, cyclic, or branched saturated alkyl group as defined above in which all hydrogens have been replaced with fluorine (e.g., trifluoromethyl, perfluoroethyl, perfluoropropyl, perfluorobutyl, perfluoroisopropyl, perfluorocyclohexyl, and the like).

[0040] The disclosed and claimed precursors are preferably substantially free of organic impurities derived from raw materials used during synthesis or by-products generated during synthesis. Examples include, but are not limited to, alkanes, alkenes, alkynes, dienes, ethers, esters, acetates, amines, ketones, amides, aromatic compounds, and the like. As used herein, "free" of organic impurities means 1000 ppm or less by weight as measured by GC, preferably 500 ppm or less by weight as measured by GC, and most preferably 100 ppm or less by weight as measured by GC or other analytical characterization. Importantly, the precursors preferably have a purity of 98% by weight or greater, more preferably 99% by weight or greater, as measured by GC, when used as precursors for depositing ruthenium-containing films.

[0041] The section headings used herein are for organizational purposes only and should not be construed as limiting the subject matter described. All references or portions thereof cited herein, including but not limited to patents, patent applications, papers, books, and treatises, are incorporated herein in their entirety for all purposes. In the event that the definitions of terms in any of the references and similar materials cited herein conflict with those herein, the definitions herein shall control. DETAILED DESCRIPTION OF THE INVENTION

[0042] It should be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not intended to be limiting with respect to the invention as claimed. The objects, features, advantages, and concepts of the disclosed invention will be apparent to those skilled in the art from the description set forth herein, and the disclosed invention can be readily implemented by those skilled in the art based on the description set forth herein. Any descriptions of "preferred embodiments" and / or examples indicating preferred modes for carrying out the disclosed invention are included for illustrative purposes and are not intended to limit the scope of the claims.

[0043] It will also be apparent to those skilled in the art that various modifications may be made in the practice of the disclosed invention based on the aspects described herein without departing from the spirit and scope of the invention disclosed herein.

[0044] In one embodiment, the disclosed and claimed invention relates to a method for thermal ALE processing of metals and their alloys (collectively "metals"). The method generally includes: (i) forming a chlorinated metal-containing layer on a metal surface by exposing the surface to a chlorinating agent; (ii) conducting a first purge to remove excess chlorinating agent and / or reaction products; (iii) forming volatile etch products on the metal surface by exposing the chlorinated metal-containing layer to at least one vaporizing agent; and (iv) conducting a second purge to remove the resulting volatile etch products. In yet another aspect of this embodiment, the method includes, as step (iA), forming the chlorinating agent used in step (i). In yet another aspect, the method consists essentially of steps (i), (ii), (iii), and (iv). In yet another aspect, the method consists of steps (i), (ii), (iii), and (iv). In yet another aspect, the method consists essentially of steps (iA), (i), (ii), (iii), and (iv). In yet another aspect, the method consists of steps (iA), (i), (ii), (iii), and (iv).

[0045] Specific aspects of the disclosed and claimed invention are exemplified below.

[0046] metal As previously mentioned, the disclosed and claimed invention relates to the thermal ALE processing of metals and their alloys (collectively "metals"). Suitable metals include, but are not limited to, cobalt, nickel, copper, molybdenum, ruthenium, tungsten, and alloys containing these.

[0047] In one embodiment, the metal comprises cobalt (Co).

[0048] In one embodiment, the metal comprises nickel (Ni).

[0049] In one embodiment, the metal comprises copper (Cu).

[0050] In one embodiment, the metal comprises molybdenum (Mo).

[0051] In one embodiment, the metal comprises ruthenium (Ru).

[0052] In one embodiment, the metal comprises tungsten (W).

[0053] Chlorinating Agent As previously noted, the chlorinating agent of the disclosed and claimed invention is thionyl chloride (SOCl) or the reaction product of thionyl chloride and pyridine. Without being bound by theory, it is believed that pyridine activates thionyl chloride to form a reactive adduct with thionyl chloride, thereby more effectively chlorinating metals.

[0054] In one embodiment, the disclosed and claimed method includes, as step (iA), forming the chlorinating agent used in step (i). In step (iA), the chlorinating agent is formed by combining thionyl chloride (SOCl) with pyridine, which is then used in step (i). In one aspect of this embodiment, thionyl chloride (SOCl) and pyridine are combined to form the chlorinating agent prior to use in step (i). In another aspect of this embodiment, thionyl chloride (SOCl) and pyridine are combined in situ during step (i). In this aspect, the metal surface to be treated with the chlorinating agent in step (i) is sequentially exposed to one of thionyl chloride (SOCl) and pyridine, followed by the other of thionyl chloride (SOCl) and pyridine.

[0055] Chlorinated metal-containing layer As previously described, step (i) of the disclosed and claimed invention involves reacting a chlorinating agent with the surface of a metal to form a chlorinated metal-containing layer on the surface. As will be appreciated by those skilled in the art, the nature of the chlorinated metal will depend on the metal being treated. For example, in one embodiment, where the metal comprises cobalt, the chlorinated metal of the chlorinated metal-containing layer has the formula CoCl x (s), where x is a value from about 1 to about 2.

[0056] Vaporizer In another aspect of this embodiment, the at least one vaporizing agent in step (iii) comprises one or more of hexafluoroacetylacetone (Hhfac), acetylacetone (Hacac), and formic acid. In one aspect of this embodiment, the at least one vaporizing agent comprises hexafluoroacetylacetone (Hhfac). In one aspect of this embodiment, the at least one vaporizing agent comprises acetylacetone (Hacac). In one aspect of this embodiment, the at least one vaporizing agent comprises formic acid.

[0057] In another aspect of this embodiment, the volatile etch product of step (iii) is a compound of formula CoCl x Hfac y (g) where x is 0 or 1 and y is 1 or 2. In one aspect of this embodiment, the volatile etch product of step (iii) has the formula CoCl(hfac). In one aspect of this embodiment, the volatile etch product of step (iii) has the formula Co(hfac).

[0058] temperature As previously described, step (i) of the disclosed and claimed invention is performed at elevated temperatures. In one embodiment, step (i) is performed at a temperature between about 100°C and about 350°C. In one embodiment, step (i) is performed at a temperature between about 100°C and about 200°C. In one embodiment, step (i) is performed at a temperature between about 140°C and about 325°C. In one embodiment, step (i) is performed at a temperature between about 140°C and about 300°C. In one embodiment, step (i) is performed at a temperature between about 140°C and about 275°C. In one embodiment, step (i) is performed at a temperature between about 150°C and about 300°C. In one embodiment, step (i) is performed at a temperature between about 150°C and about 275°C. In one embodiment, step (i) is performed at a temperature between about 175°C and about 275°C. In one embodiment, step (i) is performed at a temperature between about 200°C and about 275°C. In one embodiment, step (i) is performed at a temperature between about 225°C and about 275°C. In one embodiment, step (i) is performed at a temperature between about 200°C and about 250°C. In one embodiment, step (i) is performed at a temperature of about 100°C. In one embodiment, step (i) is performed at a temperature of about 110°C. In one embodiment, step (i) is performed at a temperature of about 120°C. In one embodiment, step (i) is performed at a temperature of about 130°C. In one embodiment, step (i) is performed at a temperature of about 140°C. In one embodiment, step (i) is performed at a temperature of about 150°C. In one embodiment, step (i) is performed at a temperature of about 160°C. In one embodiment, step (i) is performed at a temperature of about 170°C. In one embodiment, step (i) is performed at a temperature of about 180°C. In one embodiment, step (i) is performed at a temperature of about 190°C. In one embodiment, step (i) is performed at a temperature of about 200°C. In one embodiment, step (i) is performed at a temperature of about 210°C. In one embodiment, step (i) is performed at a temperature of about 220°C. In one embodiment, step (i) is performed at a temperature of about 230°C. In one embodiment, step (i) is performed at a temperature of about 240°C. In one embodiment, step (i) is performed at a temperature of about 250°C. In one embodiment, step (i) is performed at a temperature of about 260°C.In one embodiment, step (i) is performed at a temperature of about 270°C. In one embodiment, step (i) is performed at a temperature of about 280°C. In one embodiment, step (i) is performed at a temperature of about 290°C. In one embodiment, step (i) is performed at a temperature of about 300°C. In one embodiment, step (i) is performed at a temperature of about 310°C. In one embodiment, step (i) is performed at a temperature of about 320°C. In one embodiment, step (i) is performed at a temperature of about 325°C. In one preferred embodiment, step (i) is performed at a temperature of about 350°C.

[0059] As previously described, step (iii) of the disclosed and claimed invention is performed at elevated temperatures. In one embodiment, step (iii) is performed at a temperature between about 100°C and about 350°C. In one embodiment, step (iii) is performed at a temperature between about 100°C and about 200°C. In one embodiment, step (iii) is performed at a temperature between about 140°C and about 350°C. In one embodiment, step (iii) is performed at a temperature between about 140°C and about 325°C. In one embodiment, step (iii) is performed at a temperature between about 140°C and about 300°C. In one embodiment, step (iii) is performed at a temperature between about 140°C and about 275°C. In one embodiment, step (iii) is performed at a temperature between about 150°C and about 300°C. In one embodiment, step (iii) is performed at a temperature between about 150°C and about 275°C. In one embodiment, step (iii) is performed at a temperature between about 175°C and about 275°C. In one embodiment, step (iii) is carried out at a temperature between about 200°C and about 275°C. In one embodiment, step (iii) is carried out at a temperature between about 225°C and about 275°C. In one embodiment, step (iii) is carried out at a temperature between about 200°C and about 250°C. In one embodiment, step (iii) is carried out at a temperature of about 100°C. In one embodiment, step (iii) is carried out at a temperature of about 110°C. In one embodiment, step (iii) is carried out at a temperature of about 120°C. In one embodiment, step (iii) is carried out at a temperature of about 130°C. In one embodiment, step (iii) is carried out at a temperature of about 140°C. In one embodiment, step (iii) is carried out at a temperature of about 150°C. In one embodiment, step (iii) is carried out at a temperature of about 160°C. In one embodiment, step (iii) is carried out at a temperature of about 170°C. In one embodiment, step (iii) is carried out at a temperature of about 180°C. In one embodiment, step (iii) is carried out at a temperature of about 190°C. In one embodiment, step (iii) is performed at a temperature of about 200° C. In one embodiment, step (iii) is performed at a temperature of about 210° C. In one embodiment, step (iii) is performed at a temperature of about 220° C. In one embodiment, step (iii) is performed at a temperature of about 230° C.In one embodiment, step (iii) is performed at a temperature of about 240°C. In one embodiment, step (iii) is performed at a temperature of about 250°C. In one embodiment, step (iii) is performed at a temperature of about 260°C. In one embodiment, step (iii) is performed at a temperature of about 270°C. In one embodiment, step (iii) is performed at a temperature of about 280°C. In one embodiment, step (iii) is performed at a temperature of about 290°C. In one embodiment, step (iii) is performed at a temperature of about 300°C. In one embodiment, step (iii) is performed at a temperature of about 310°C. In one embodiment, step (iii) is performed at a temperature of about 320°C. In one embodiment, step (iii) is performed at a temperature of about 325°C. In one preferred embodiment, step (iii) is performed at a temperature of about 350°C.

[0060] In one embodiment, steps (i) and (iii) are each performed at about the same temperature. In yet another aspect of this embodiment, steps (i) and (iii) are each performed at the same temperature. In another embodiment, steps (i) and (iii) are each performed at different temperatures.

[0061] cycle As will be appreciated by those skilled in the art, steps (i) and (iii) of the disclosed and claimed invention may be performed iteratively to achieve a desired degree of etching. A single cycle of the disclosed and claimed method comprises: (Step (i)) n +(Step (iii)) m Including, where n and m are independently 1 to 20 and represent the number of times (i.e., the number of repetitions) that step (i) and step (iii) are performed within a single cycle. As will be understood by those skilled in the art, the disclosed and claimed methods include a purge step (ii) when proceeding from step (i) to step (iii), as well as an additional purge step (iv) before beginning a new cycle (i.e., when proceeding from step (iii) to step (i)). However, a purge step need not occur between repetitions of a single step (e.g., between multiple repetitions of step (i) or between multiple repetitions of step (iii)). Thus, a single cycle can be understood to begin with the first repetition of step (i) and end with a final purge step (iv) before another repetition of step (i) is performed, regardless of the number of purge steps performed during the process.

[0062] In one embodiment, n and m are the same.

[0063] In one embodiment, n and m are different.

[0064] In one embodiment, n is the same as m. In one embodiment, n is different from m.

[0065] In one embodiment, n is 1. In one embodiment, n is 2. In one embodiment, n is 3. In one embodiment, n is 4. In one embodiment, n is 5. In one embodiment, n is 6. In one embodiment, n is 7. In one embodiment, n is 8. In one embodiment, n is 9. In one embodiment, n is 10. In one embodiment, n is 11. In one embodiment, n is 12. In one embodiment, n is 13. In one embodiment, n is 14. In one embodiment, n is 15. In one embodiment, n is 16. In one embodiment, n is 17. In one embodiment, n is 18. In one embodiment, n is 19. In one embodiment, n is 20.

[0066] In one embodiment, m is 1. In one embodiment, m is 2. In one embodiment, m is 3. In one embodiment, m is 4. In one embodiment, m is 5. In one embodiment, m is 6. In one embodiment, m is 7. In one embodiment, m is 8. In one embodiment, m is 9. In one embodiment, m is 10. In one embodiment, m is 11. In one embodiment, m is 12. In one embodiment, m is 13. In one embodiment, m is 14. In one embodiment, m is 15. In one embodiment, m is 16. In one embodiment, m is 17. In one embodiment, m is 18. In one embodiment, m is 19. In one embodiment, m is 20.

[0067] In one embodiment, n is 1 and m is 1. In one embodiment, n is 2 and m is 2. In one embodiment, n is 3 and m is 3. In one embodiment, n is 4 and m is 4. In one embodiment, n is 5 and m is 5. In one embodiment, n is 6 and m is 6. In one embodiment, n is 7 and m is 7. In one embodiment, n is 8 and m is 8. In one embodiment, n is 9 and m is 9. In one embodiment, n is 10 and m is 10. In one embodiment, n is 11 and m is 11. In one embodiment, n is 12 and m is 12. In one embodiment, n is 13 and m is 13. In one embodiment, n is 14 and m is 14. In one embodiment, n is 15 and m is 15. In one embodiment, n is 16 and m is 16. In one embodiment, n is 17 and m is 17. In one embodiment, n is 18 and m is 18. In one embodiment, n is 19 and m is 19. In one embodiment, n is 20 and m is 20.

[0068] In one embodiment, each repetition of step (i) alternates with a repetition of step (iii) within each cycle (i.e., step (iii) alternates between each repetition of step (i)). In another embodiment, all repetitions of step (i) begin and complete before any repetition of step (iii) begins and completes within each cycle.

[0069] Number of cycles The disclosed and claimed methods can include any number of cycles desired. In one embodiment, the number of cycles is from about 10 to about 5,000. In one embodiment, the number of cycles is from about 10 to about 1,000. In one embodiment, the number of cycles is from about 50 to about 2,500. In one embodiment, the number of cycles is from about 50 to about 1,500. In one embodiment, the number of cycles is from about 50 to about 1,000. In one embodiment, the number of cycles is from about 50 to about 750. In one embodiment, the number of cycles is from about 50 to about 500. In one embodiment, the number of cycles is from about 50 to about 300. In one embodiment, the number of cycles is from about 50 to about 200. In one embodiment, the number of cycles is from about 10 to about 50. In one embodiment, the number of cycles is from about 150 to about 4,000. In one embodiment, the number of cycles is from about 200 to about 3,000. In one embodiment, the number of cycles is from about 250 to about 2500. In one embodiment, the number of cycles is from about 350 to about 2000. In one embodiment, the number of cycles is from about 450 to about 1700. In one embodiment, the number of cycles is from about 500 to about 1500. In one embodiment, the number of cycles is from about 750 to about 1250. In one embodiment, the number of cycles is from about 250 to about 1000. In one embodiment, the number of cycles is from about 500 to about 1000. In one embodiment, the number of cycles is from about 750 to about 1000.

[0070] In one embodiment, the number of cycles is about 10. In one embodiment, the number of cycles is about 20. In one embodiment, the number of cycles is about 30. In one embodiment, the number of cycles is about 40. In one embodiment, the number of cycles is about 50. In one embodiment, the number of cycles is about 100. In one embodiment, the number of cycles is about 125. In one embodiment, the number of cycles is about 150. In one embodiment, the number of cycles is about 175. In one embodiment, the number of cycles is about 200. In one embodiment, the number of cycles is about 250. In one embodiment, the number of cycles is about 300. In one embodiment, the number of cycles is about 350. In one embodiment, the number of cycles is about 400. In one embodiment, the number of cycles is about 450. In one embodiment, the number of cycles is about 500. In one embodiment, the number of cycles is about 750. In one embodiment, the number of cycles is about 1000. In one embodiment, the number of cycles is about 1250. In one embodiment, the number of cycles is about 1500. In one embodiment, the number of cycles is about 1750. In one embodiment, the number of cycles is about 2000. In one embodiment, the number of cycles is about 2250. In one embodiment, the number of cycles is about 2500. In one embodiment, the number of cycles is about 2750. In one embodiment, the number of cycles is about 3000. In one embodiment, the number of cycles is about 3250. In one embodiment, the number of cycles is about 3500. In one embodiment, the number of cycles is about 4000. In one embodiment, the number of cycles is about 4500. In one embodiment, the number of cycles is about 5000.

[0071] time In one embodiment of the disclosed and claimed invention, each repetition of step (i) can take from about 0.1 seconds to about 60 seconds. In one embodiment of the disclosed and claimed invention, each repetition of step (i) can take from about 20 seconds to about 60 seconds. In one embodiment of the disclosed and claimed invention, each repetition of step (i) can take from about 5 seconds to about 20 seconds. In one embodiment of the disclosed and claimed invention, each repetition of step (i) can take from about 1 second to about 5 seconds. In one embodiment, each repetition of step (i) can take from about 0.2 seconds to about 0.9 seconds. In one embodiment, each repetition of step (i) can take from about 0.3 seconds to about 0.8 seconds. In one embodiment, each repetition of step (i) can take from about 0.4 seconds to about 0.7 seconds. In one embodiment, each repetition of step (i) takes about 0.1 seconds. In one embodiment, each repetition of step (i) takes about 0.2 seconds. In one embodiment, each repetition of step (i) takes about 0.3 seconds. In one embodiment, each repetition of step (i) takes about 0.4 seconds. In one embodiment, each repetition of step (i) takes about 0.5 seconds. In one embodiment, each repetition of step (i) takes about 0.6 seconds. In one embodiment, each repetition of step (i) takes about 0.7 seconds. In one embodiment, each repetition of step (i) takes about 0.8 seconds. In one embodiment, each repetition of step (i) takes about 0.9 seconds. In one embodiment, each repetition of step (i) takes about 1 second. In one embodiment, each repetition of step (i) takes about 2 seconds. In one embodiment, each repetition of step (i) takes about 3 seconds. In one embodiment, each repetition of step (i) takes about 4 seconds. In one embodiment, each repetition of step (i) takes about 5 seconds. In one embodiment, each repetition of step (i) takes about 7 seconds. In one embodiment, each repetition of step (i) takes about 10 seconds. In one embodiment, each repetition of step (i) takes about 15 seconds. In one embodiment, each repetition of step (i) takes about 20 seconds. In one embodiment, each repetition of step (i) takes about 30 seconds. In one embodiment, each repetition of step (i) takes about 40 seconds. In one embodiment, each repetition of step (i) takes about 50 seconds. In one embodiment, each repetition of step (i) takes about 60 seconds.

[0072] In one embodiment of the disclosed and claimed invention, each repetition of step (iii) may take from about 0.1 seconds to about 60 seconds. In one embodiment of the disclosed and claimed invention, each repetition of step (iii) may take from about 20 seconds to about 60 seconds. In one embodiment of the disclosed and claimed invention, each repetition of step (iii) may take from about 5 seconds to about 20 seconds. In one embodiment of the disclosed and claimed invention, each repetition of step (iii) may take from about 1 second to about 5 seconds. In one embodiment, each repetition of step (iii) may take from about 0.2 seconds to about 0.9 seconds. In one embodiment, each repetition of step (iii) may take from about 0.3 seconds to about 0.8 seconds. In one embodiment, each repetition of step (iii) may take from about 0.4 seconds to about 0.7 seconds. In one embodiment, each repetition of step (iii) takes about 0.1 seconds. In one embodiment, each repetition of step (iii) takes about 0.2 seconds. In one embodiment, each repetition of step (iii) takes about 0.3 seconds. In one embodiment, each repetition of step (iii) takes about 0.4 seconds. In one embodiment, each repetition of step (iii) takes about 0.5 seconds. In one embodiment, each repetition of step (iii) takes about 0.6 seconds. In one embodiment, each repetition of step (iii) takes about 0.7 seconds. In one embodiment, each repetition of step (iii) takes about 0.8 seconds. In one embodiment, each repetition of step (iii) takes about 0.9 seconds. In one embodiment, each repetition of step (iii) takes about 1 second. In one embodiment, each repetition of step (iii) takes about 2 seconds. In one embodiment, each repetition of step (iii) takes about 3 seconds. In one embodiment, each repetition of step (iii) takes about 4 seconds. In one embodiment, each repetition of step (iii) takes about 5 seconds. In one embodiment, each repetition of step (iii) takes about 7 seconds. In one embodiment, each repetition of step (iii) takes about 10 seconds. In one embodiment, each repetition of step (iii) takes about 15 seconds. In one embodiment, each repetition of step (iii) takes about 20 seconds. In one embodiment, each repetition of step (iii) takes about 30 seconds. In one embodiment, each repetition of step (iii) takes about 40 seconds. In one embodiment, each repetition of step (iii) takes about 50 seconds.In one embodiment, each repetition of step (iii) takes about 60 seconds.

[0073] In one embodiment, each repetition of step (i) within a cycle takes approximately the same amount of time. In one embodiment, one or more repetitions of step (i) within a cycle take a different amount of time than other repetitions of step (i) within the same cycle.

[0074] In one embodiment, each repetition of step (iii) within a cycle takes approximately the same amount of time, hi one embodiment, one or more repetitions of step (iii) within a cycle take a different amount of time than other repetitions of step (iii) within the same cycle.

[0075] In one embodiment, each cycle of step (i) takes approximately the same amount of time as each repetition of step (iii) within the same cycle, hi one embodiment, each repetition of step (i) within the same cycle takes a different amount of time than each sample of step (iii) within the same cycle.

[0076] Exemplary Description of Cycles In one embodiment, for example, one cycle comprises six 0.4 second step (i) administrations of SOCl and pyridine, followed by six 0.2 second step (iii) of Hhfac. This cycle can be represented as "6(0.4s SOCl-Py) / 6(0.2s Hhfac)."

[0077] In one embodiment, for example, one cycle includes a step (i) pulse of a certain amount of SOCl2 vapor, a step (iA) pulse of a certain amount of pyridine vapor, and a step (iii) pulse of a certain amount of Hhfac vapor.

[0078] metal As previously described, the disclosed and claimed methods provide selective thermal etching on certain metal substrates. In one aspect, the disclosed and claimed methods etch substrates comprising one or more of cobalt, nickel, copper, molybdenum, ruthenium, and tungsten. In one aspect, the disclosed and claimed methods etch substrates comprising cobalt. In one aspect, the disclosed and claimed methods etch substrates comprising nickel. In one aspect, the disclosed and claimed methods etch substrates comprising copper. In one aspect, the disclosed and claimed methods etch substrates comprising molybdenum. In one aspect, the disclosed and claimed methods etch substrates comprising ruthenium. In one aspect, the disclosed and claimed methods etch substrates comprising tungsten.

[0079] Chamber (reactor) pressure SOCl2 pressure In one embodiment, SOCl2 is supplied into the chamber through one inlet, and an inert gas is simultaneously supplied into the chamber through the same inlet. In one embodiment, SOCl2 is supplied into the chamber through one inlet, and an inert gas is simultaneously supplied into the chamber through another inlet. In one embodiment, SOCl2 is supplied by flowing an inert gas through the halogenating agent to form a mixed vapor. In one embodiment, SOCl2 is supplied alone. In one embodiment, the total pressure in the chamber during SOCl2 supply is from about 0.1 Torr to about 1.0 Torr. In one embodiment, the total pressure in the chamber during SOCl2 supply is from about 0.5 Torr to about 5.0 Torr. In one embodiment, the total pressure in the chamber during SOCl2 supply is from about 0.5 Torr to about 2.0 Torr. In one embodiment, the total pressure in the chamber during SOCl2 supply is from about 0.5 Torr to about 1.0 Torr. In one embodiment, the total pressure in the chamber during the supply of SOCl2 is from about 0.5 Torr to about 0.75 Torr. In one embodiment, the total pressure in the chamber during the supply of SOCl2 is from about 1.0 Torr to about 5.0 Torr. In one embodiment, the total pressure in the chamber during the supply of SOCl2 is from about 1.0 Torr to about 10.0 Torr. In one embodiment, the total pressure in the chamber during the supply of SOCl2 is from about 2.0 Torr to about 10.0 Torr. In one embodiment, the total pressure in the chamber during the supply of SOCl2 is from about 10.0 Torr to about 25.0 Torr. In one embodiment, the total pressure in the chamber during the supply of SOCl2 is from about 10.0 Torr to about 50.0 Torr. In one embodiment, the total pressure in the chamber during the supply of SOCl2 is from about 25.0 Torr to about 50.0 Torr. In one embodiment, the total pressure in the chamber during the supply of SOCl2 is from about 50.0 Torr to about 75.0 Torr. In one embodiment, the total pressure in the chamber during the supply of SOCl2 is from about 75.0 Torr to about 100.0 Torr. In one embodiment, the total pressure in the chamber during the supply of SOCl2 is from about 1.0 Torr to about 100.0 Torr. In one embodiment, the total pressure in the chamber during the supply of SOCl2 is from about 10.0 Torr to about 100.0 Torr.

[0080] Supply method In one embodiment, SOCl2 is provided by vapor draw. In one embodiment, SOCl2 is provided by passing an inert gas through a container of SOCl2.

[0081] Steps (ii) and (iv) Purging Purge Gas Any suitable inert purge gas may be used when performing step (ii) and / or step (iv). In one embodiment, the purge gas comprises argon. In one embodiment, the purge gas comprises nitrogen.

[0082] In one embodiment, the purge gas in step (ii) and step (iv) is the same. In one embodiment, the purge gas in step (ii) and step (iv) is different.

[0083] time In one embodiment, the step (ii) and / or step (iv) purge time is from about 0.5 seconds to about 10 seconds. In one embodiment, the step (ii) and / or step (iv) purge time exposure is from about 1 second to about 7 seconds. In one embodiment, the step (ii) and / or step (iv) purge time exposure is from about 7 seconds to about 10 seconds. In one embodiment, the step (ii) and / or step (iv) purge time exposure is from about 10 seconds to about 20 seconds. In one embodiment, the step (ii) and / or step (iv) purge time exposure is from about 20 seconds to about 30 seconds. In one embodiment, the step (ii) and / or step (iv) purge time exposure is from about 30 seconds to about 60 seconds. In one embodiment, the step (ii) and / or step (iv) purge time exposure is about 0.25 seconds. In one embodiment, the step (ii) and / or step (iv) purge time exposure is about 0.5 seconds. In one embodiment, the step (ii) and / or step (iv) purge time exposure is about 1 second. In one embodiment, the step (ii) and / or step (iv) purge time exposure is about 2 seconds. In one embodiment, the step (ii) and / or step (iv) purge time exposure is about 3 seconds. In one embodiment, the step (ii) and / or step (iv) purge time exposure is about 4 seconds. In one embodiment, the step (ii) and / or step (iv) purge time exposure is about 5 seconds. In one embodiment, the step (ii) and / or step (iv) purge time exposure is about 6 seconds. In one embodiment, the step (ii) and / or step (iv) purge time exposure is about 7 seconds. In one embodiment, the step (ii) and / or step (iv) purge time exposure is about 8 seconds. In one embodiment, the step (ii) and / or step (iv) purge time exposure is about 9 seconds. In one embodiment, the step (ii) and / or step (iv) purge time exposure is about 10 seconds. In one embodiment, the step (ii) and / or step (iv) purge time exposure is about 12 seconds.In one embodiment, the step (ii) and / or step (iv) purge time exposure is about 15 seconds. In one embodiment, the step (ii) and / or step (iv) purge time exposure is about 17 seconds. In one embodiment, the step (ii) and / or step (iv) purge time exposure is about 20 seconds. In one embodiment, the step (ii) and / or step (iv) purge time exposure is about 25 seconds. In one embodiment, the step (ii) and / or step (iv) purge time exposure is about 30 seconds. In one embodiment, the step (ii) and / or step (iv) purge time exposure is about 40 seconds. In one embodiment, the step (ii) and / or step (iv) purge time exposure is about 50 seconds. In one embodiment, the step (ii) and / or step (iv) purge time exposure is about 60 seconds.

[0084] In one embodiment, the purge gas in step (ii) and step (iv) is flowed for the same time period. In another embodiment, the purge gas in step (ii) and step (iv) is flowed for different time periods.

[0085] flow rate When performing step (ii) and / or step (iv), the purge gas is flowed at between about 1 sccm and about 2000 sccm. In one embodiment, the step (ii) and / or step (iv) purge gas is flowed at between about 3 sccm and about 8 sccm. In one embodiment, the step (ii) and / or step (iv) purge gas is flowed at between about 50 sccm and about 500 sccm. In one embodiment, the step (ii) and / or step (iv) purge gas is flowed at between about 500 sccm and about 2000 sccm. In one embodiment, the step (ii) and / or step (iv) purge gas is flowed at about 1 sccm. In one embodiment, the step (ii) and / or step (iv) purge gas is flowed at about 2 sccm. In one embodiment, the step (ii) and / or step (iv) purge gas is flowed at about 3 sccm. In one embodiment, the step (ii) and / or step (iv) purge gas is flowed at about 4 sccm. In one embodiment, the step (ii) and / or step (iv) purge gas is flowed at about 5 sccm. In one embodiment, the step (ii) and / or step (iv) purge gas is flowed at about 6 sccm. In one embodiment, the step (ii) and / or step (iv) purge gas is flowed at about 7 sccm. In one embodiment, the step (ii) and / or step (iv) purge gas is flowed at about 8 sccm. In one embodiment, the step (ii) and / or step (iv) purge gas is flowed at about 9 sccm. In one embodiment, the step (ii) and / or step (iv) purge gas is flowed at about 10 sccm. In one embodiment, the step (ii) and / or step (iv) purge gas is flowed at about 9 sccm. In one embodiment, the step (ii) and / or step (iv) purge gas is flowed at about 10 sccm, in one embodiment, the step (ii) and / or step (iv) purge gas is flowed at about 50 sccm, and in one embodiment, the step (ii) and / or step (iv) purge gas is flowed at about 100 sccm.In one embodiment, the step (ii) and / or step (iv) purge gas is flowed at about 200 sccm. In one embodiment, the step (ii) and / or step (iv) purge gas is flowed at about 300 sccm. In one embodiment, the step (ii) and / or step (iv) purge gas is flowed at about 500 sccm. In one embodiment, the step (ii) and / or step (iv) purge gas is flowed at about 750 sccm. In one embodiment, the step (ii) and / or step (iv) purge gas is flowed at about 1000 sccm. In one embodiment, the step (ii) and / or step (iv) purge gas is flowed at about 1250 sccm. In one embodiment, the step (ii) and / or step (iv) purge gas is flowed at about 1500 sccm. In one embodiment, the step (ii) and / or step (iv) purge gas is flowed at about 1750 sccm. In one embodiment, the step (ii) and / or step (iv) purge gas is flowed at about 2000 sccm.

[0086] In one embodiment, the purge gas in step (ii) and step (iv) is passed at the same flow rate. In another embodiment, the purge gas in step (ii) and step (iv) is passed at different flow rates.

[0087] film The disclosed and claimed invention further includes films formed by the methods described herein.

[0088] In one embodiment, a film etched by the method described herein has trenches, vias, or other topographical features with an aspect ratio of from about 0 to about 60. In yet another aspect of this embodiment, the aspect ratio is from about 0 to about 0.5. In yet another aspect of this embodiment, the aspect ratio is from about 0.5 to about 1. In yet another aspect of this embodiment, the aspect ratio is from about 1 to about 50. In yet another aspect of this embodiment, the aspect ratio is from about 1 to about 40. In yet another aspect of this embodiment, the aspect ratio is from about 1 to about 30. In yet another aspect of this embodiment, the aspect ratio is from about 1 to about 20. In yet another aspect of this embodiment, the aspect ratio is from about 1 to about 10. In yet another aspect of this embodiment, the aspect ratio is about 0.1. In yet another aspect of this embodiment, the aspect ratio is about 0.2. In yet another aspect of this embodiment, the aspect ratio is about 0.3. In yet another aspect of this embodiment, the aspect ratio is about 0.4. In yet another aspect of this embodiment, the aspect ratio is about 0.5. In yet another aspect of this embodiment, the aspect ratio is about 0.6. In yet another aspect of this embodiment, the aspect ratio is about 0.8. In yet another aspect of this embodiment, the aspect ratio is about 1. In yet another aspect of this embodiment, the aspect ratio is greater than about 1. In yet another aspect of this embodiment, the aspect ratio is greater than about 2. In yet another aspect of this embodiment, the aspect ratio is greater than about 5. In yet another aspect of this embodiment, the aspect ratio is greater than about 10. In yet another aspect of this embodiment, the aspect ratio is greater than about 15. In yet another aspect of this embodiment, the aspect ratio is greater than about 20. In yet another aspect of this embodiment, the aspect ratio is greater than about 30. In yet another aspect of this embodiment, the aspect ratio is greater than about 40. In yet another aspect of this embodiment, the aspect ratio is greater than about 50. In yet another aspect of the above embodiment and those aspects, the metal comprises cobalt, nickel, copper, molybdenum, ruthenium, and tungsten. In yet another aspect of the above embodiment and those aspects, the metal comprises cobalt.In yet another aspect of the above embodiment and aspects thereof, the metal comprises nickel. In yet another aspect of the above embodiment and aspects thereof, the metal comprises copper. In yet another aspect of the above embodiment and aspects thereof, the metal comprises molybdenum. In yet another aspect of the above embodiment and aspects thereof, the metal comprises ruthenium. In yet another aspect of the above embodiment and aspects thereof, the metal comprises tungsten.

[0089] In another embodiment, a film etched by the methods described herein has a resistivity between about 1 μΩ.cm and about 250 μΩ.cm. In yet another aspect of this embodiment, the film has a resistivity between about 1 μΩ.cm and about 5 μΩ.cm. In yet another aspect of this embodiment, the film has a resistivity between about 3 μΩ.cm and about 4 μΩ.cm. In yet another aspect of this embodiment, the film has a resistivity between about 5 μΩ.cm and about 10 μΩ.cm. In yet another aspect of this embodiment, the film has a resistivity between about 10 μΩ.cm and about 50 μΩ.cm. In yet another aspect of this embodiment, the film has a resistivity between about 50 μΩ.cm and about 100 μΩ.cm. In yet another aspect of this embodiment, the film has a resistivity between about 100 μΩ.cm and about 250 μΩ.cm. In yet another aspect of this embodiment, the film has a resistivity of about 1 μΩ.cm. In yet another aspect of this embodiment, the film has a resistivity of about 2 μΩ.cm. In yet another aspect of this embodiment, the film has a resistivity of about 3 μΩ.cm. In yet another aspect of this embodiment, the film has a resistivity of about 4 μΩ.cm. In yet another aspect of this embodiment, the film has a resistivity of about 5 μΩ.cm. In yet another aspect of this embodiment, the film has a resistivity of about 7.5 μΩ.cm. In yet another aspect of this embodiment, the film has a resistivity of about 10 μΩ.cm. In yet another aspect of this embodiment, the film has a resistivity of about 15 μΩ.cm. In yet another aspect of this embodiment, the film has a resistivity of about 20 μΩ.cm. In yet another aspect of this embodiment, the film has a resistivity of about 30 μΩ.cm. In yet another aspect of this embodiment, the film has a resistivity of about 40 μΩ.cm. In yet another aspect of this embodiment, the film has a resistivity of about 50 μΩ.cm. In yet another aspect of this embodiment, the film has a resistivity of about 60 μΩ.cm. In yet another aspect of this embodiment, the film has a resistivity of about 80 μΩ.cm. In yet another aspect of this embodiment, the film has a resistivity of about 100 μΩ.cm. In yet another aspect of this embodiment, the film has a resistivity of about 150 μΩ.cm. In yet another aspect of this embodiment, the film has a resistivity of about 200 μΩ.cm.In yet another aspect of this embodiment, the film has a resistivity of about 250 μΩ·cm. [Example]

[0090] More specific embodiments of the present disclosure and experimental results supporting such embodiments are described below. These examples are provided below to more fully explain the disclosed invention, and should not be construed as limiting the disclosed invention in any way.

[0091] It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed invention and the specific examples provided herein without departing from the spirit or scope of the disclosed invention. Thus, the disclosed invention, including the description provided by way of example below, is intended to cover modifications and variations of the disclosed invention that come within the scope of any claims and their equivalents.

[0092] Materials and Methods: In Examples 1 to 5, the etching process was carried out in a warm-walled chamber system. This system included a process chamber equipped with an in-situ multi-wavelength ellipsometer, a load lock, and an ultra-high vacuum analysis chamber equipped with an Auger electron microscope (AES). Samples were introduced into the system on a 2-inch stainless steel puck, which could be transported between chambers using a linear transfer arm. During processing, the sample was heated to a constant temperature using two PID-controlled halogen lamps. Argon (99.999% purity, Arc3 gas) was used as the carrier and purge gas at a flow rate of 95 sccm, set by a mass flow controller. The process chamber was evacuated using a turbopump (Seiko Seiki STP-300C) and a backing pump (Alcatel 2021a) equipped with a throttle valve installed before the turbopump, which was used to control the operating pressure, which was set at 400 mTorr. Thionyl chloride (SOCl2) and pyridine were obtained from MilliporeSigma.

[0093] In Examples 6 through 10, the ALE process was performed in an ALD system equipped with a showerhead lid heated to 130 °C. This ALD system had the capacity to accommodate wafers up to 300 mm in diameter. The ALD system also had a heated pedestal on which the wafer was placed. For each experiment, a 44 mm × 44 mm test substrate was placed on a 300 mm silicon carrier wafer. The pedestal was heated to a temperature approximately 10–20 °C higher than the intended sample temperature to account for temperature gradients across the carrier wafer. Thionyl chloride (SOCl), pyridine, and hexafluoroacetylacetone (Hhfac) were obtained from MilliporeSigma. All chemicals were administered by pulsing vapors from a sample set at 30 °C. All chemicals were administered to the ALD system one at a time; multiple chemicals were not administered simultaneously. Between chemical doses, the chemicals were diluted in a 400-600 sccm argon purge flow, and the ALD chamber pressure was maintained at 2000 mTorr. After each chemical dose, the chamber was purged with approximately 2000 sccm argon for 60 seconds. Film thickness was measured using X-ray fluorescence analysis.

[0094] Example 1: SOCl2 (alone) vs. pyridine (alone) vs. SOCl2 + pyridine The surface changes of Co were compared between SOCl2 and pyridine co-dosing and SOCl2 or pyridine alone at 250 °C. The surface changes of Co upon reactant exposure were monitored by tracking the delta parameter measured at 635 nm from in situ spectroscopic ellipsometry. The Co surface tested had a 30 nm layer of sputtered Co on a 3 nm TaN adhesion layer on Si. Co substrates approximately 1.5 cm x 1.5 cm were used for the experiment without surface cleaning. A 0.4 second SOCl2 and pyridine co-dosing (SOCl2-Py) sub-dosing was used.

[0095] The initial delta parameter of the Co substrate varied between about 135 and about 142, likely due to the presence of impurities and a surface cobalt oxide layer. As shown in Figure 1, the delta parameter (Δ; measured at 635 nm) did not change after exposure to SOCl (30 subdoses) or pyridine (320 subdoses) alone, whereas co-dosing of SOCl and pyridine (20 subdoses) resulted in a significant decrease in the delta parameter from about 135 to about 120. These results indicate that no reaction occurred on the Co substrate when SOCl or pyridine was administered alone. On the other hand, the data demonstrate that co-dosing of SOCl and pyridine resulted in an unexpectedly large decrease in the delta parameter (i.e., demonstrating that the Co surface was reactive to the co-dosing of SOCl and pyridine, despite not being reactive to SOCl or pyridine individually).

[0096] Example 2: Other chlorinating agents As shown in Figure 2, other known chlorinating agents were analyzed under similar conditions (e.g., at 250°C) to determine whether they would surface chlorinate the Co surface. The agents tested included: BCl, TiCl, AlCl, and Al(CH)Cl. From Figure 2, it can be seen that there was no significant change in the delta parameter (Δ; measured at 635 nm) after 30 doses of each of BCl, TiCl, Al(CH)Cl, and AlCl. This data indicates that the Co surface was unreactive to BCl, TiCl, AlCl, and Al(CH)Cl.

[0097] Example 3: Cobalt chlorination with SOCl2 + pyridine In situ Auger electron microscopy (AES) was used to analyze the surface chemical changes after co-dosing with SOCl2 and pyridine at 250 °C. Elemental compositions were measured in atomic percent (at.%) from in situ AES for Co before and after SOCl2-Py exposure (Table 1). In Table 1, the as-received (untreated) Co surface showed approximately 36 at.% Co and 38 at.% oxygen (O) due to the presence of surface cobalt oxide, 21 at.% carbon (C) derived from adventitious carbon or impurities, and 5 at.% chlorine (Cl). After 10 sub-doses of SOCl2-Py, the at.% of Cl showed a significant increase from 5 at.% to 32 at.%. The increase in Cl content evidenced the chlorination of Co upon exposure to SOCl2-Py.

[0098] [Table 1] Example 4: Cobalt ALE using SOCl2 + pyridine and Hhfac Chemical analysis using ex situ X-ray photoelectron spectroscopy (XPS) was performed to determine the CO etching after various etching cycles at 250 °C. Each etching cycle consisted of six 0.4 s SOCl and pyridine co-doses (SOCl-Py) followed by six 0.2 s Hhfac subdoses (etching cycle exposure sequence: 6 (0.4 s SOCl-Py) / 6 (0.2 s Hhfac)). High-resolution scans of Co2p and Ta4f after two, four, six, and eight etching cycles at 250 °C are shown in Figure 3. All Co samples exhibited Co peaks centered at approximately 797 and 781 eV, which are attributed to CoOx (Figure 3a). Increasing the number of etching cycles reduced the Co peak intensity. Additionally, Ta peaks located at 26.5 and 28.2 eV appeared after six or more etching cycles (Figure 3b). The decrease in the Co signal accompanied by the appearance of the Ta signal demonstrated that the Co film was removed as a result of etching.

[0099] Example 5: Cobalt ALE using SOCl2 + pyridine and Hhfac Table 2 summarizes the measured effects and temperature dependence of Co etching using in situ AES. The elemental composition of the Co substrate was analyzed after six etching cycles at 140°C, 170°C, 250°C, and 275°C, respectively (etching cycle exposure sequence: 6 (0.4 s SOCl2-Py) / 6 (0.2 s Hhfac)). At 250°C and 275°C, the samples showed Co concentrations ranging from 2 to 0 at.% after six etching cycles, suggesting that the Co film was mostly removed, while the Ta concentration ranged from about 18 at.% to about 19 at.%. However, when the temperature was lowered to 140°C, the residual Co content increased to 24 at.%. This suggests that the lower the temperature, the less Co was removed, and therefore the etching process is temperature-dependent.

[0100] [Table 2] Example 6: Cobalt ALE using SOCl2, pyridine and / or Hhfac In each experiment in this example, the sample was a 44 mm x 44 mm silicon sample that was coated with approximately 166 to 182 Å of Co by physical vapor deposition (PVD). The initial resistivity of the Co was approximately 28 to 33 μohm-cm. In this example, the pedestal temperature was set to 270°C for an approximate sample temperature of 260°C.

[0101] Each Co sample was loaded onto a 300 mm silicon carrier wafer into an ALD system and subjected to 20 ALD cycles. Each cycle consisted of two or more sequential doses of the following chemicals: thionyl chloride, pyridine, and / or Hhfac. The ALD system was purged with argon after each dose. Additional experiments were performed using the same three-step process, except that only argon carrier gas was dosed into the ALD system, to evaluate the effect of process conditions (i.e., temperature) on the Co films. The results are summarized in Table 3 below. No etching was observed in the process that did not contain both SOCl2 and Hhfac. The SOCl2 / pyridine / Hhfac process resulted in the most significant etching, while the pyridine / SOCl2 / Hhfac process showed similar results to the SOCl2 / Hhfac process. There was no significant difference in resistivity between samples exposed to the etching chemistries and those treated in argon alone. However, all processes showed a significant decrease in resistivity compared to virgin Co.

[0102] [Table 3] Example 7: Cobalt ALE with SOCl2 and Hhfac For each experiment in this example, the sample was a 44 mm x 44 mm silicon sample that was coated with approximately 169 to 209 Å of Co by physical vapor deposition (PVD). The initial resistivity of the Co was approximately 28 to 33 μohm-cm. In this example, the pedestal temperature was set to 210°C, 240°C, or 270°C for approximate sample temperatures of 200°C, 230°C, or 260°C, respectively.

[0103] Each Co sample was loaded onto a 300 mm silicon carrier wafer into an ALD system and subjected to 20, 40, or 60 ALE cycles. Each cycle consisted of successive doses of thionyl chloride and Hhfac. The ALD system was purged with argon after each dose. The results are summarized in Table 4 below. Significant Co etching is observed at sample temperatures as low as 200 °C. The amount of Co etching increases with temperature and cycle number. A linear fit of Co thickness change vs. cycle number indicates that after a delay of approximately 32 cycles at 230 °C, the etching per cycle is approximately 1.2 Å / cycle, and after a delay of approximately 16 cycles at 260 °C, the etching is approximately 3.0 Å / cycle. Resistivity is lower than the pre-ALE value for samples that etched to approximately 13 Å. However, samples that etched more significantly show increasing resistivity with the amount of etching. The sample treated at 260° C. for 60 cycles shows the greatest etching (129±2 Å) with incomparably higher resistivity compared to the other samples in Table 4.

[0104] [Table 4] Example 8: Cobalt ALE using SOCl2, pyridine and Hhfac In each experiment in this example, the sample was a 44 mm x 44 mm silicon sample that was coated with approximately 169 to 207 Å of Co by physical vapor deposition (PVD). The initial resistivity of the Co was approximately 28 to 33 μohm-cm. In this example, the pedestal temperature was set to 210°C, 240°C, or 270°C for approximate sample temperatures of 200°C, 230°C, or 260°C, respectively.

[0105] Each Co sample was loaded onto a 300 mm silicon carrier wafer into an ALD system and subjected to 20, 40, or 60 ALE cycles. Each cycle consisted of sequential doses of thionyl chloride, followed by pyridine, and then Hhfac. The ALD system was purged with argon after each dose. The results are summarized in Table 5 below. Significant Co etching is observed at low sample temperatures of 230 °C. The Co etching amount generally increases with temperature and cycle number. The etching amount is identical for samples etched at 230 °C using 40 or 60 ALE cycles; this may be due to effects related to the native oxide on the Co surface or nonuniformity between each sample. A linear fit of Co thickness change vs. cycle number indicates an etching rate per cycle of approximately 1.2 Å / cycle after a delay of approximately 26 cycles at 230 °C and approximately 3.7 Å / cycle after a delay of approximately 15 cycles at 260 °C. For samples that etched to about 25 Å, the resistivity was lower than the pre-ALE value. However, samples that etched more significantly showed resistivity that increased with the amount of etching. Samples treated at 260°C for 40 or 60 cycles showed the greatest etching (97±2 Å or 163±2 Å, respectively), with resistivity incomparable to the other samples in Table 5.

[0106] [Table 5] Example 9: Molybdenum ALE with SOCl2 and Hhfac In each experiment in this example, the sample was a 44 mm × 44 mm silicon sample that was coated with approximately 200 Å of Mo by physical vapor deposition (PVD). The initial resistivity of Mo was approximately 21 to 22 μohm-cm. In this example, the pedestal temperature was set at 210 °C or 270 °C for approximate sample temperatures of 200 °C or 260 °C, respectively. Each Mo sample was loaded into an ALD system on a 300 mm silicon carrier wafer and subjected to 40 ALD cycles. Each cycle consisted of sequential doses of thionyl chloride and Hhfac. The ALD system was purged with argon after each dose.

[0107] There was no significant change in the Mo film or resistivity after ALE at 200°C.

[0108] After ALE at 260°C, approximately 9 Å of Mo was removed, with no significant change in Mo resistivity.

[0109] Example 10: Molybdenum ALE using SOCl2, pyridine and Hhfac For each experiment in this example, the sample was a 44 mm x 44 mm silicon sample that was coated with approximately 200 Å of Mo by physical vapor deposition (PVD). The initial resistivity of the Mo was approximately 21 to 22 μohm-cm. In this example, the pedestal temperature was set to 210°C or 270°C for approximate sample temperatures of 200°C or 260°C, respectively.

[0110] Each Mo sample was loaded onto a 300 mm silicon carrier wafer into an ALD system and subjected to 40 ALD cycles. Each cycle consisted of sequential doses of thionyl chloride, followed by pyridine, and then Hhfac. The ALD system was purged with argon after each dose.

[0111] There was no significant change in the Mo film or resistivity after ALE at 200°C.

[0112] After ALE at 260°C, approximately 11 Å of Mo was removed, with no significant change in Mo resistivity.

[0113] Summary of examples The use of a combination of thionyl chloride (SOCl2) and pyridine as a surface chlorination reagent for thermal ALE of Co was demonstrated in Examples 1–5. In-vacuum AES revealed that co-dosing with pyridine-SOCl2 resulted in approximately 30 at.% Cl on the Co surface. Specifically, the surface changes of Co at 250 °C were compared between the co-dosing of SOCl2 and pyridine and the single SOCl2, pyridine, and other known chlorinating agents. The surface changes of Co upon reactant exposure were monitored by tracking the delta parameter measured at 635 nm using in situ spectroscopic ellipsometry. Co-dosing of SOCl2 and pyridine showed a significant decrease in the delta value, whereas no such change was observed for the other materials tested.

[0114] Additionally, in situ AES analysis revealed surface changes due to co-dosing, whereas comparative dosing using SOCl2, pyridine, or other known chlorinating agents alone was unchanged. Co removal was confirmed by ex situ XPS, which showed a decrease in Co content with successive SOCl2-py / Hhfac exposures, accompanied by an increase in the Tg signal from the underlying TaN layer. Furthermore, the etching behavior, i.e., its temperature dependence, with SOCl2-py / Hhfac was demonstrated to be controllable.

[0115] Experiments using a 300 mm ALD reactor (Examples 6–10) demonstrate that Co can be controllably etched by cycling between SOCl and Hhfac or SOCl, pyridine, and Hhfac. When either SOCl or Hhfac is not included in the ALD cycle, no etching occurs. Etching per cycle between about 1 Å / cycle and about 4 Å / cycle was achieved at sample temperatures from about 200°C to about 260°C. This process removed up to about 25 Å of Co without significant changes in Co resistivity. Mo could also be etched at 260°C without significant changes in Mo resistivity. In many cases, the process using SOCl, pyridine, and Hhfac etched more than the process using SOCl and Hhfac under otherwise similar etching conditions.

[0116] While the disclosed and claimed invention has been described and illustrated with a certain degree of detail, it will be apparent that this disclosure is made by way of example only and that one skilled in the art may resort to numerous variations in the conditions and sequence of steps without departing from the spirit and scope of the disclosed and claimed invention.

Claims

1. 1. A thermal ALE method for selectively etching a metal substrate, carried out in a reactor, comprising the steps of: (i) forming a chlorinated metal-containing layer on a metal surface by exposing the surface to a chlorinating agent; (ii) conducting a first purge to remove excess chlorinating agent and / or reaction products; (iii) forming volatile etching products on the surface of the metal by exposing the chlorinated metal-containing layer to at least one vaporizing agent; and (iv) performing a second purge to remove volatile etching products; The method comprising:

2. The chlorinating agent is thionyl chloride (SOCl ２ 10. The method of claim 1, wherein the hydroxybenzoate is formed by mixing hydroxybenzoate with pyridine.

3. The chlorinating agent is thionyl chloride (SOCl ２ 10. The method of claim 1, comprising:

4. A method according to any one of claims 1 to 3, wherein the metal comprises one or more of cobalt, nickel, copper, molybdenum, ruthenium, tungsten and alloys containing these.

5. A method according to any one of claims 1 to 3, wherein the chlorinated metal comprises one or more of cobalt, nickel, copper, molybdenum, ruthenium, tungsten and alloys containing these.

6. 4. The method of any one of claims 1 to 3, wherein step (i) is carried out at a temperature between about 100°C and about 350°C, wherein the term "about" refers to the stated value of the variable, as well as all values ​​of the variable within ±10% of the stated value.

7. 4. The method of any one of claims 1 to 3, wherein step (iii) is carried out at a temperature between about 100°C and about 350°C, wherein the term "about" refers to the stated value of the variable, as well as all values ​​of the variable within ±10% of the stated value.

8. The method of any one of claims 1 to 3, wherein steps (i) and (iii) are carried out at the same temperature.

9. The method of any one of claims 1 to 3, wherein steps (i) and (iii) are carried out at different temperatures.

10. 4. A metal-containing film etched by the method of any one of claims 1 to 3, wherein the metal-containing film comprises one or more of cobalt, nickel, copper, molybdenum, ruthenium, tungsten, and alloys containing any of these.

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