Isotropic thermal atomic layer etching of zirconium and hafnium oxides.

Abstract

The disclosed and claimed invention relates to (1) a method for performing thermal atomic layer etching (ALE) of films including ZrO2, HfO2, (Hf-Zr)O2 alloys or similar materials that does not require the use of plasma or corrosive halogenated chemicals, and (2) a metal-insulator-metal capacitor (MIMcap) with unique properties enabled by a unique dielectric processing method.

Description

[Technical field]

[0001] The disclosed and claimed invention relates to a method for performing thermal atomic layer etching (ALE) of films including ZrO2, HfO2, (Hf-Zr)O2 alloys or similar materials without the use of plasma or corrosive halogenated chemicals. The disclosed and claimed invention also includes a metal-insulator-metal capacitor (MIMcap) with unique properties enabled by a unique dielectric processing method that includes the steps of: (i) growing a film of ZrO2, HfO2 or (Hf-Zr)O2 alloys that is thicker than the final desired thickness; (ii) heat treating the film to achieve desired properties (e.g., high-κ, low leakage, and / or ferroelectricity); and (iii) performing isotropic ALE to remove a portion of the thickness of the film, where the resulting thinned film retains the desirable properties of the initially grown (i.e., thicker) film. [Background technology]

[0002] The shrinking of geometries in the semiconductor industry is the main factor behind the continuous improvement of device performance. This trend is expected to continue for at least several more generations of computer chips. In this regard, ultra-thin (<5 nm) layers of high-κ dielectrics are required for volatile and non-volatile memories including DRAM, NAND flash, and ferroelectric memories. In order for this trend to continue, several technological challenges need to be successfully solved.

[0003] Atomic layer deposition (ALD) is a technique that is finding increasing application in the semiconductor industry, and it is currently the deposition method that allows the best control over the amount of material deposited. In ALD, an atomic layer is deposited on all surfaces exposed to a gas-phase precursor, with the layer being at most as thick as one atomic layer. By successively exposing these surfaces to two different precursors, a layer of material of the desired thickness is deposited. The 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 the two reactive species. Coating of thin and narrow vias and other high aspect ratio features has been demonstrated many times by ALD in the literature.

[0004] Atomic Layer Etching (ALE or ALEt) can be seen as a layer-by-layer removal of material while ALD is a 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 that activates a layer of surface atoms and a second precursor that promotes the sublimation of this activated layer of atoms; occasionally a third precursor is used to regenerate the surface to conditions in which the first precursor becomes active.

[0005] For example, early copper etching methods were disclosed in which copper was chlorinated using a plasma to produce CuCl2. See, e.g., Tamirisa et al., Microelectron., 84, 1055 (2007); Wu et al., J. Electrochem. Soc., 157, H474 (2010) and Hess DW, Workshop on Atomic-Layer-Etch and Clean Technology, San Francisco, Ca (2014). The CuCl2 layer was then etched with a hydrogen plasma, which produced the volatile Cu3Cl3. This method could be performed at temperatures as low as 20°C. However, the usefulness of this method for etching copper in small features was limited due to the significant profile taper.

[0006] Other methods have involved etching tungsten. See, for example, Johnson NR and George SM, ACS Applied Materials & Interfaces, 9, 34435 (2017). In this method, a tungsten surface with a native oxide layer is etched by etching the tungsten surface with a native oxide layer, as shown in FIG. (A) a mixture of oxygen and ozone, which oxidizes an additional layer of tungsten to tungsten oxide (surface activation); (B) boron trichloride, which reacts with a portion of the tungsten oxide to produce non-volatile boron oxide and volatile tungsten oxychloride (sublimation of the tungsten-containing species; some tungsten oxide still exists beneath the boron oxide); and (C) hydrogen fluoride, which reacts with the boron oxide to produce volatile water vapor and volatile boron trifluoride (regenerating a fresh tungsten oxide surface); It was possible to etch tungsten by continuous exposure to (between 128°C and 207°C).

[0007] Another method is directed to etching cobalt. See, for example, Chen et al., J. Vac. Sci. Technol., A35, 05C305 (2017). In this method, cobalt etching at temperatures above 80° C. was achieved with an etch rate as high as 28 Å / cycle and was not self-limiting. This method converts the cobalt surface into (A) oxygen plasma, which oxidizes the cobalt layers to cobalt oxide (surface activation); and (B) formic acid, which reacts with the cobalt oxide surface species to produce volatile cobalt formate species (sublimation); Continuous exposure to

[0008] An alternative method was used to etch thin films of cobalt and copper using supercritical CO2 and 1,1,1,5,5,5-hexafluoro-2,4-pentanedione under high pressure at 100° C. and 250° C. See, for example, Rasadujjaman et al., Microelectron. Eng. 153, 5 (2016).

[0009] Other reported methods involved etching copper at temperatures above 275° C. with an etch rate of 0.09 nm / cycle. See, for example, Mohimi et al., ECS Journal of Solid State Science and Technology, 7, P491 (2018). This method converts the copper surface into (A) oxygen, which is a mild oxidizing agent that oxidizes the copper layer to copper oxide (surface activation); and (B) acetylacetone (e.g., 1,1,1,5,5,5-hexafluoro-2,4-pentanedione (HFAC)), which reacts with the copper oxide surface species to produce volatile copper acetylacetonate species (sublimation); The study involved continuous exposure to

[0010] Several cobalt etching methods have also been disclosed. See, for example, Zhao et al., Applied Surface Science, 455, 438 (2018) (Non-Patent Document 8) and Konh et al., Journal of Vacuum Science & Technology A, 37, 021004 (2019) (Non-Patent Document 9). In one of these methods, cobalt was etched by exposing a cobalt surface (having a native oxide) to 1,1,1,5,5,5-hexafluoro-2,4-pentanedione (HFAC) at temperatures above 377°C. The treated surface was then heated to sublimate the cobalt 1,1,1,5,5,5-hexafluoro-2,4-pentanedionate. In one variation, the cobalt surface was etched by exposing the cobalt surface to HFAC at temperatures above 377°C. (A) chlorine, which oxidizes the cobalt layer to cobalt chloride (surface activation); and (B) acetylacetone (e.g., 1,1,1,5,5,5-hexafluoro-2,4-pentanedione (HFAC)), which reacts with the cobalt chloride surface species to produce volatile cobalt chloro-acetylacetonate species (sublimation); The cobalt was etched at temperatures above 140° C. by continuous exposure to

[0011] Methods have been disclosed for thermal ALE of oxides including ZrO2, HfO2, Al2O3, and TiO2. See, for example, Y. Lee, C. Huffman, and S. M. George, Chem. Mater. 28 (2016) 7657-7665 (Non-Patent Document 10); PC Lemaire and GN Parsons, Chem. Mater., 29 (2017) 6653-6665 (Non-Patent Document 11); J. A. Murdzek and S. M. George, J. Vac. Sci. Technol. A38 (2020) 022608 (Non-Patent Document 12); H. Saare, PhD dissertation, North Carolina State U., 2021 (Non-Patent Document 13). These methods typically involve two repeated steps: fluorination of the oxide surface in a first step, and vaporization of the resulting surface fluoride in a second step. For the first step, the fluorinating agent may include hydrogen fluoride (HF), anhydrous hydrogen fluoride stabilized with pyridine (HF-pyridine), sulfur tetrafluoride (SF4), sulfur hexafluoride (SF6) remote plasma, tungsten hexafluoride (WF6), or xenon difluoride (XeF2), etc. For the second step, the vaporizing agent may include trimethylaluminum (TMA), dimethylaluminum chloride (DMAC), silicon tetrachloride (SiCl4), or titanium tetrachloride (TiCl4), etc.

[0012] Methods for thermal ALE of Al2O3, ZrO2, HfZrO4 and HfO2 were disclosed by Lee et al. (Y. Lee, C. Huffman, and S.M. George, Chem. Mater. 28, 7657-7665 (2016) (Non-Patent Document 14)) and Murdzek and George (J.A. Murdzek and S.M. George, J. Vac. Sci. Technol. A38, 022608 (2020) (Non-Patent Document 15)).

[0013] In

[14] , ALE tests were performed at process temperatures ranging from 150°C to 350°C. All of these metal oxides were effectively fluorinated using anhydrous HF delivered from an ampoule of HF pyridine. Al2O3 could be etched by repeated doses of anhydrous HF and either tin(ii) acetylacetonate Sn(acac)2, trimethylaluminum (TMA), dimethylaluminum chloride (DMAC) or silicon tetrachloride (SiCl4). ZrO2 could be etched by repeated doses of anhydrous HF and either Sn(acac)2, DMAC or SiCl4. HfO2 could be etched by repeated doses of anhydrous HF and either Sn(acac)2, TMA or DMAC.

[0014] In Non-Patent Document 15, ALE tests were performed at a process temperature of 250 °C. HF, SF4, and XeF2 were used as fluorination agents, and DMAC and TiCl4 were used as ligand exchange agents. In all tested chemistries, crystalline ZrO2, HfZrO4, and HfO2 were etched slower compared to amorphous ZrO2, HfZrO4, and HfO2, respectively. XeF2 was found to provide significantly more etching per cycle compared to HF or SF4.

[0015] Methods for thermal ALE of TiO2 and ZrO2 were disclosed by Lemaire and Parsons (PC Lemaire and GN Parsons, Chem. Mater., 29, 6653-6665 (2017) (Non-Patent Document 16)) and Saare (H. Saare, PhD dissertation, North Carolina State U., (2021) (Non-Patent Document 17)). In Patent Document 16, ALE tests were performed at process temperatures ranging from 120°C to 220°C. WF6 was used as the fluorinating agent, and BCl3 was used as the ligand exchange agent. This process resulted in ALE of TiO2, with B or W residues remaining on the surface. In Non-Patent Document 17, ALE tests were performed at process temperatures ranging from 160°C to 325°C. WF6 was used as the fluorinating agent, and BCl3, TiCl4 and SOCl2 were used as the ligand exchange agents. Each ALE process resulted in the ALE of TiO2 and ZrO2.

[0016] A few nanometer films of ZrO2 and HfO2 have different functional properties based on the thickness and crystal structure of the film. 0.5 Zr 0.5 The ferroelectric crystalline phase of O2 can only be stabilized once the film exceeds a certain minimum thickness (i.e., approximately 5-7 nm). If films thinner than 5-7 nm are desired (e.g., to maximize capacitance and / or reduce device size), it is necessary to first grow a relatively thick film and process it (i.e., to crystallize the film) and then remove some of the film material. Such material removal methods require sub-nanometer precision, and the removal may need to be isotropic (e.g., for conformal etching of high aspect features in 3D nanoarchitectures such as DRAM capacitors or 3D memory stacks). The best approach for this is isotropic atomic layer etching (ALE).

[0017] As described above, isotropic ALE requires repeated cycles of dosing a reactant into a chamber and then purging the chamber to remove excess reactants and reaction products. In some implementations, there are two successive dose-purge subcycles, each using a different reactant or combination of reactants. In some implementations, there are three or more successive dose-purge subcycles, each using a different reactant or combination of reactants. [Prior art documents] [Non-patent literature]

[0018] [Non-Patent Document 1] Tamirisa et al.,Microelectron.,84,1055(2007) [Non-Patent Document 2] Wu et al.,J.Electrochem.Soc.,157,H474(2010) [Non-Patent Document 3] Hess DW,Workshop on Atomic-Layer-Etch and Clean Technology,San Francisco,Ca(2014) [Non-Patent Document 4] Johnson NRand George SM,ACS Applied Materials & Interfaces,9,34435(2017) [Non-Patent Document 5] Chen et al.,J.Vac.Sci.Technol.,A 35,05C305(2017) [Non-Patent Document 6] Rasadujjaman et al.,Microelectron.Eng.153,5(2016) [Non-Patent Document 7] Mohimi et al.,ECS Journal of Solid State Science and Technology,7,P491(2018) [Non-Patent Document 8] Zhao et al.,Applied Surface Science,455,438(2018)

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[0019] All of the methods described above allow for etching of metals using either oxygen plasma or halogen-containing reactants. However, plasma can be destructive to the substrate, and many halogens can lead to contamination. Therefore, new etching reagents, such as those used in the disclosed and claimed invention (tungsten hexafluoride, WF6), do not require plasma and do not contain corrosive halogens. Therefore, a method that does not require plasma or induced ions is highly desirable.

[0020] Although HF is widely used in ALE processing, its highly corrosive and toxic nature makes it difficult to handle safely. In addition, since HF is a very polar molecule, it tends to adhere to the inner walls of the reactor chamber during processing, which requires long purging times to ensure its removal. See, for example, Xie et al., J.Vac.Sci.Technol.A,022605(2020). Therefore, an ALE method that does not rely on HF would be highly advantageous for implementation. [Means for solving the problem]

[0021] In one aspect, the disclosed and claimed invention comprises a method for producing a ferroelectric material comprising the steps of: xZr 1-x The present invention relates to a method for isotropic thermal ALE of metal oxides including ZrO2 and other HfO2 based materials, TiO2, Al2O3 and combinations thereof, including 02 (x is a value between 0 and 1, including but not limited to 0.5), and engineered impurities or dopants, comprising, or consisting essentially of, (i) a first surface modification step comprising exposing a surface of a metal oxide substrate to one or more fluorinating agents to produce a fluorinated surface, (ii) a first purging step, (iii) a ligand exchange step comprising exposing the fluorinated surface to one or more chlorine ligand providing agents to produce volatile chlorinated species, (iv) a second purging step, (v) a second surface modification step comprising exposing the surface of the metal oxide substrate to one or more oxidizing agents to oxidize metal by-products, and (vi) a third purging step. The steps in the process can be repeated as many times as necessary to remove the desired thickness of metal oxide. An optional post-treatment step (vii) may be added to remove impurities remaining on the surface after multiple cycles.

[0022] In another aspect, the disclosed and claimed invention relates to metal-insulator-metal capacitor ("MIMcap") devices fabricated using the disclosed and claimed ALE methods. In yet another aspect, the MIMcap devices ideally exhibit a higher dielectric constant (k) and lower leakage current compared to an otherwise equivalent MIMcap fabricated without the disclosed and claimed ALE methods.

[0023] 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, which are further described below.

[0024] The order in which the different steps described herein are presented is for the sake of clarity. In general, the steps disclosed herein may be performed in any suitable order. Additionally, although different features, techniques, configurations, etc. described herein may each be described in different parts of this specification, it is intended that each of these concepts can be practiced independently of one another or in combination with one another, where appropriate. Thus, the invention as disclosed and claimed can be embodied and viewed in many different ways.

[0025] The accompanying drawings provide a further understanding of the disclosed invention, and are incorporated in and constitute a part of this specification, illustrating embodiments of the disclosed invention and, together with the detailed description of the invention, serve to explain the principles of the disclosed invention. [Brief description of the drawings]

[0026] [Figure 1] FIG. 1 shows an exemplary cycle of the disclosed and claimed ALE method utilizing ZrO2, WF6, DMAC and an oxidant.

[0027] definition Unless otherwise stated, the following terms used in the specification and claims have the following meanings in this application.

[0028] For purposes of the disclosed and claimed invention, the numbering convention for the Periodic Table Groups follows the IUPAC Periodic Table of the Elements.

[0029] 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."

[0030] The terms "substituent," "residue," "group," and "moiety" may be used interchangeably.

[0031] 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 deposition method such as, for example, ALD or CVD. The metal-containing complex can be deposited, adsorbed, decomposed, delivered and / or distributed onto a substrate or a surface thereof such that a metal-containing film is formed.

[0032] As used herein, the term "metal-containing film" includes elemental metal films, as defined in more detail below, as well as films that contain one or more elements in addition to the 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 consist essentially 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 otherwise indicated by context, the term "metal film" is to be construed to mean an elemental metal film.

[0033] As used herein, the term "vapor deposition method" is used to refer 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 photoassisted CVD. CVD can also take the form of a pulse 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 processes, see, for example, George SM, et al. J. Phys. Chem., 100, 13121-13131 (1996). In other embodiments, ALD can take the form of conventional (i.e., pulsed injection) ALD, liquid injection ALD, photoassisted ALD, plasma-assisted ALD, or plasma-enhanced ALD. The term "vapor deposition process" further includes various vapor deposition techniques described in Chemical Vapour Deposition: Precursors, Processes, and Applications; Jones, AC; Hitchman, ML, Eds., The Royal Society of Chemistry: Cambridge, Chapter 1, pp. 1-36 (2009) (Non-Patent Document 20).

[0034] As used herein, the term "feature" refers to an opening in a substrate that may be defined by one or more sidewalls, a bottom surface, and a top corner. In various aspects, the feature may be a via, a trench, a contact, a dual damascene, etc.

[0035] 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.

[0036] The disclosed and claimed precursors are preferably substantially free of water. As used herein, the term "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.

[0037] The disclosed and claimed precursors include 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 unintentional presence of metal ions or metals such as (Cr), titanium (Ti), vanadium (V), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu) or zinc (Zn). These metal ions or metals are potentially present from the raw materials / reactors used to synthesize the precursor. As used herein, the term "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 it comes to the unintentional presence of Li, Na, K, Mg, Ca, Al, Fe, Ni, Cr, Ti, V, Mn, Co, Ni, Cu or Zn.

[0038] Unless otherwise indicated, "alkyl" refers to a C1-C6 alkyl group that can be linear or branched (e.g., methyl, ethyl, propyl, isopropyl, tert-butyl, and the like), or cyclic (e.g., cyclohexyl, cyclopropyl, cyclopentyl, and the like). 20The term "alkyl" refers to a hydrocarbon group, the alkyl portion of which may be substituted or unsubstituted as described below. 20 It refers to such moieties having carbon. For structural reasons, linear alkyl is understood to start from C1, while branched alkyl and cyclic alkyl are understood to start from C3. Furthermore, moieties derived from alkyl as described below, such as alkyloxy and perfluoroalkyl, are understood to have the same carbon number range unless otherwise stated. If a different alkyl group length is specified above, the above definition of alkyl is still valid in that it includes all types of alkyl moieties above, and the above structural considerations regarding the minimum carbon number of a given type of alkyl group still apply.

[0039] 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.

[0040] Alkyl halides are fully or partially halogenated C1-C 20 Refers to alkyl.

[0041] Perfluoroalkyl refers to a linear, cyclic or branched saturated alkyl group as defined above in which all hydrogens have been replaced by fluorines (eg, trifluoromethyl, perfluoroethyl, perfluoropropyl, perfluorobutyl, perfluoroisopropyl, perfluorocyclohexyl, and the like).

[0042] The disclosed and claimed precursors are preferably substantially free of organic impurities originating 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, aromatics, etc. As used herein, the term "free" of organic impurities means less than 1000 ppm as measured by GC, preferably less than 500 ppm (by weight) as measured by GC, and most preferably less than 100 ppm (by weight) as measured by GC or other analytical characterization. Importantly, the precursors preferably have a purity of 98% by weight or more, more preferably 99% by weight or more, as measured by GC, when used as precursors for depositing ruthenium-containing films.

[0043] 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 of references 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 incorporated herein conflict with those herein, the definitions herein shall control. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] It should be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not intended to be limiting with respect to the invention as set forth in the claims. The objectives, features, advantages and concepts of the disclosed invention will be apparent to those skilled in the art from the description set forth herein, and further, the disclosed invention can be easily implemented by those skilled in the art based on the description set forth herein. Any description of a "preferred embodiment" and / or examples showing a preferred mode for carrying out the disclosed invention is included for illustrative purposes and is not intended to limit the scope of the claims.

[0045] 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.

[0046] As previously described, the disclosed and claimed invention is based on the use of ZrO2, HfO2, Hf x Zr 1-x The present invention relates to a method for isotropic thermal ALE of metal oxides including ZrO2 and other HfO2 based materials, TiO2, Al2O3 and combinations thereof, with x being a value between 0 and 1, and with engineered impurities or dopants, the method comprising: (i) a first surface modification step comprising exposing a surface of a metal oxide substrate to one or more fluorinating agents to produce a fluorinated surface; (ii) a first purge step; (iii) a ligand exchange step comprising exposing the fluorinated surface to one or more chlorine ligand donors to generate volatile chlorinated species; (iv) a second purge step; (v) a second surface modification step comprising exposing the surface of the metal oxide substrate to one or more oxidizing agents to oxidize metal by-products; and (vi) a third purge step; Comprising, consisting essentially of, or consisting of.

[0047] In yet another aspect of this embodiment, the method consists essentially of steps (i), (ii), (iii), (iv), (v) and (vi). In yet another aspect of this embodiment, the method consists of steps (i), (ii), (iii), (iv), (v) and (vi). The steps in the process can be repeated as necessary to remove the desired thickness of metal oxide. In yet another aspect, any of the above embodiments can further include a post-treatment step (vii) to remove impurities remaining on the surface after multiple cycles. In this case, the method comprises, consists essentially of or consists of steps (i), (ii), (iii), (iv), (v), (vi) and (vii).

[0048] Number of cycles As described above, the disclosed and claimed ALE method may repeat the steps as necessary to remove the desired thickness of metal oxide. In the above embodiment, as well as other embodiments described herein, the recited steps define one cycle of the method. As one skilled in the art will appreciate (and as described above), the disclosed and claimed method includes a purge step (ii) when going from step (i) to step (iii), a purge step (iv) when going from step (iii) to step (v), and an additional purge step (vi) before starting a new cycle (i.e., when going from step (v) to step (i)). However, a purge step need not occur between iterations of a single step (e.g., between multiple iterations of step (i), between multiple iterations of step (iii), or between multiple iterations of step (v)). Thus, a single cycle may be understood to begin when the first iteration of step (i) is performed and end when the last purge step (vi) is performed before another iteration of step (i), regardless of the number of purge steps performed during the method. It will be appreciated that the cycle can be repeated until the desired thickness of the film is obtained.

[0049] In one embodiment, the number of cycles is from about 100 to about 1000. In one embodiment, the number of cycles is from about 20 to about 250. In one embodiment, the number of cycles is from about 10 to about 150. In one embodiment, the number of cycles is from about 5 to about 100. In one embodiment, the number of cycles is from about 5 to about 75. In one embodiment, the number of cycles is from about 5 to about 50. In one embodiment, the number of cycles is from about 5 to about 30. In one embodiment, the number of cycles is from about 5 to about 20. In one embodiment, the number of cycles is from about 15 to about 400. In one embodiment, the number of cycles is from about 20 to about 300. In one embodiment, the number of cycles is from about 25 to about 250. In one embodiment, the number of cycles is from about 35 to about 200. In one embodiment, the number of cycles is from about 45 to about 170. In one embodiment, the number of cycles is from about 50 to about 150. In one embodiment, the number of cycles is from about 75 to about 125. In one embodiment, the number of cycles is from about 25 to about 100. In one embodiment, the number of cycles is from about 50 to about 100. In one embodiment, the number of cycles is from about 75 to about 100.

[0050] In one embodiment, the number of cycles is about 5. In one embodiment, the number of cycles is about 10. In one embodiment, the number of cycles is about 15. In one embodiment, the number of cycles is about 20. In one embodiment, the number of cycles is about 25. In one embodiment, the number of cycles is about 30. In one embodiment, the number of cycles is about 35. In one embodiment, the number of cycles is about 40. In one embodiment, the number of cycles is about 45. In one embodiment, the number of cycles is about 50. In one embodiment, the number of cycles is about 75. 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 225. In one embodiment, the number of cycles is about 250. In one embodiment, the number of cycles is about 275. In one embodiment, the number of cycles is about 300. In one embodiment, the number of cycles is about 325. 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.

[0051] Steps (i) through (vi) of the disclosed and claimed method are described in more detail below.

[0052] Step (i) First Surface Modification In the first surface modification step (i), one or more metal oxides (e.g., ZrO2, HfO2, Hf x Zr 1-xAt least one fluorinating agent is used to convert a surface comprising, consisting essentially of, or consisting of ZrO2 and HfO2 based materials, including ZrO2 (x is a value between 0 and 1, and other materials based on HfO2, including engineered impurities or dopants), to the corresponding fluorinated species, thereby producing a fluorinated metal surface. In this step, the one or more metal oxides are exposed to the fluorinating agent for a period of time before proceeding to step (ii).

[0053] As one of ordinary skill in the art will appreciate, the initial exposure of the metal oxide surface to a fluorinating agent (not shown in FIG. 1) will produce by-products on the surface (e.g., the use of WF as the fluorinating agent will result in W species (e.g., WO x , x between 2 and 3), which contaminate the surface and slow or stop the etching process over time. Therefore, the disclosed and claimed method includes step (v) in which such species are oxidized to species that can be easily vaporized upon exposure to a fluorinating agent when step (i) is repeated during the next cycle.

[0054] (a) Metal oxide The metal oxides include any acceptable and / or desired metal oxide. In one embodiment, the metal oxides include ZrO2, HfO2, Hf x Zr 1-x The metal oxide may include one or more of ZrO2 (where x is a value between 0 and 1), other materials based on HfO2 with engineered impurities or dopants, TiO2, Al2O3, and combinations thereof. In one aspect of this embodiment, the metal oxide includes ZrO2. In one aspect of this embodiment, the metal oxide includes HfO2. In one aspect of this embodiment, the metal oxide includes Hf x Zr 1-xIn one aspect of this specific embodiment, m is 0.02, where x is a value between 0 and 1. In one aspect of this specific embodiment, m is 0.1. In one aspect of this specific embodiment, m is 0.2. In one aspect of this specific embodiment, m is 0.3. In one aspect of this specific embodiment, m is 0.4. In one aspect of this specific embodiment, m is 0.5. In one aspect of this specific embodiment, m is 0.6. In one aspect of this specific embodiment, m is 0.7. In one aspect of this specific embodiment, m is 0.8. In one aspect of this specific embodiment, m is 0.9. In one aspect of this specific embodiment, m is 0.95. In one aspect of this embodiment, the metal oxide comprises ZrO2 and HfO2 based materials including engineered impurities. In one aspect of this embodiment, the metal oxide comprises TiO2. In one aspect of this embodiment, the metal oxide comprises Al2O3.

[0055] (b) Fluorinating agent The fluorinating agent may include one or more metal fluorides. In one aspect of this embodiment, the one or more metal fluorides are one or more of VF5, NbF5, TaF5, MoF6, WF6, ReF6, and ReF7. In one aspect of this embodiment, the one or more metal fluorides include VF5. In one aspect of this embodiment, the one or more metal fluorides include NbF5. In one aspect of this embodiment, the one or more metal fluorides include TaF5. In one aspect of this embodiment, the one or more metal fluorides include MoF6. In one aspect of this embodiment, the one or more metal fluorides include WF6. In one aspect of this embodiment, the one or more metal fluorides include ReF6. In one aspect of this embodiment, the one or more metal fluorides include ReF7.

[0056] The fluorinating agent may alternatively or additionally comprise one or more metalloid fluorides. In one aspect of this embodiment, the one or more metalloid fluorides are one or more of AsF5, SbF5, and TeF6. In one aspect of this embodiment, the one or more metal fluorides comprise AsF5. In one aspect of this embodiment, the one or more metal fluorides comprise SbF5. In one aspect of this embodiment, the one or more metal fluorides comprise TeF6.

[0057] The fluorinating agent may alternatively or additionally comprise one or more metal-free or metalloid-free fluorinating agents, such as one or more of anhydrous HF, HF-pyridine, XeF2, SF4, and combinations thereof. Thus, in one embodiment, the fluorinating agent comprises one or more non-metal or non-metalloid fluorides. Although these metal-free and metalloid-free fluorinating agents are considered to be part of the disclosed and claimed invention, these materials are highly corrosive and therefore generally not preferred for use in the disclosed and claimed methods. Thus, in another embodiment, the fluorinating agent is substantially free of non-metal or non-metalloid fluorides. In another embodiment, the fluorinating agent is free of non-metal or non-metalloid fluorides.

[0058] (c) Conditions time As described above, in step (i), the one or more metal oxides are exposed to the fluorinating agent for a period of time ("exposure time") before proceeding to step (ii). In one embodiment, the exposure time of the first surface modification in step (i) is from about 0.5 seconds to about 30 seconds. In one embodiment, the exposure time of the first surface modification in step (i) is from about 0.5 seconds to about 10 seconds. In one embodiment, the exposure time of the first surface modification in step (i) is from about 1 second to about 7 seconds. In one embodiment, the exposure time of the first surface modification in step (i) is from about 7 seconds to about 10 seconds. In one embodiment, the exposure time of the first surface modification in step (i) is from about 10 seconds to about 20 seconds. In one embodiment, the exposure time of the first surface modification in step (i) is from about 20 seconds to about 30 seconds. In one embodiment, the exposure time of the first surface modification in step (i) is about 0.25 seconds. In one embodiment, the exposure time of the first surface modification in step (i) is about 0.5 seconds. In one embodiment, the exposure time of the first surface modification in step (i) is about 1 second. In one embodiment, the exposure time of the first surface modification in step (i) is about 2 seconds. In one embodiment, the exposure time of the first surface modification in step (i) is about 3 seconds. In one embodiment, the exposure time of the first surface modification in step (i) is about 4 seconds. In one embodiment, the exposure time of the first surface modification in step (i) is about 5 seconds. In one embodiment, the exposure time of the first surface modification in step (i) is about 6 seconds. In one embodiment, the exposure time of the first surface modification in step (i) is about 7 seconds. In one embodiment, the exposure time of the first surface modification in step (i) is about 8 seconds. In one embodiment, the exposure time of the first surface modification in step (i) is about 9 seconds. In one embodiment, the exposure time of the first surface modification in step (i) is about 10 seconds. In one embodiment, the exposure time of the first surface modification in step (i) is about 12 seconds. In one embodiment, the exposure time of the first surface modification in step (i) is about 15 seconds. In one embodiment, the exposure time of the first surface modification in step (i) is about 17 seconds. In one embodiment, the exposure time of the first surface modification in step (i) is about 20 seconds. In one embodiment, the exposure time of the first surface modification in step (i) is about 25 seconds.In one embodiment, the exposure time for the first surface modification in step (i) is about 30 seconds.

[0059] Fluorinating agent flow rate In one embodiment, the fluorinating agent is flowed at about 5 sccm to about 500 sccm. In one embodiment, the fluorinating agent is flowed at about 0.5 sccm to about 100 sccm. In one embodiment, the fluorinating agent is flowed at about 1 sccm to about 200 sccm. In one embodiment, the fluorinating agent is flowed at about 1 sccm to about 100 sccm. In one embodiment, the fluorinating agent is flowed at about 1 sccm to about 50 sccm. In one embodiment, the fluorinating agent is flowed at about 5 sccm to about 25 sccm. In one embodiment, the fluorinating agent is flowed at about 10 sccm to about 20 sccm. In one embodiment, the fluorinating agent is flowed at about 15 sccm to about 25 sccm. In one embodiment, the fluorinating agent is flowed at about 5 sccm. In one embodiment, the fluorinating agent is flowed at about 10 sccm. In one embodiment, the fluorinating agent is flowed at about 15 sccm. In one embodiment, the fluorinating agent is flowed at about 20 sccm. In one embodiment, the fluorinating agent is flowed at about 25 sccm. In one embodiment, the fluorinating agent is flowed at about 30 sccm. In one embodiment, the fluorinating agent is flowed at about 35 sccm. In one embodiment, the fluorinating agent is flowed at about 40 sccm. In one embodiment, the fluorinating agent is flowed at about 45 sccm. In one embodiment, the fluorinating agent is flowed at about 50 sccm. In one embodiment, the fluorinating agent is flowed at about 60 sccm. In one embodiment, the fluorinating agent is flowed at about 70 sccm. In one embodiment, the fluorinating agent is flowed at about 80 sccm. In one embodiment, the fluorinating agent is flowed at about 90 sccm. In one embodiment, the fluorinating agent is flowed at about 100 sccm. In one embodiment, the fluorinating agent is flowed at about 125 sccm. In one embodiment, the fluorinating agent is flowed at about 150 sccm. In one embodiment, the fluorinating agent is flowed at about 200 sccm. In one embodiment, the fluorinating agent is flowed at about 250 sccm. In one embodiment, the fluorinating agent is flowed at about 300 sccm. In one embodiment, the fluorinating agent is flowed at about 350 sccm. In one embodiment, the fluorinating agent is flowed at about 400 sccm. In one embodiment, the fluorinating agent is flowed at about 450 sccm.In one embodiment, the fluorinating agent is flowed at about 500 sccm.

[0060] In one embodiment, the fluorinating agent is provided alone.

[0061] In one embodiment, the fluorinating agent is delivered using a suitable carrier gas. In one embodiment, the carrier gas comprises argon. In one embodiment, the carrier gas comprises nitrogen.

[0062] pressure The first surface modification of step (i) can be carried out at any suitable chamber pressure. In one embodiment, the pressure is from about 0.5 torr to about 100 torr. The first surface modification of step (i) can be carried out at any suitable chamber pressure. In one embodiment, the pressure is from about 5 torr to about 100 torr. In one embodiment, the pressure is from about 0.5 torr to about 15 torr. In one embodiment, the pressure is from about 1 torr to about 12 torr. In one embodiment, the pressure is from about 1 torr to about 10 torr. In one embodiment, the pressure is from about 1 torr to about 5 torr. In one embodiment, the pressure is from about 1 torr to about 2 torr. In one embodiment, the pressure is from about 0.5 torr to about 5 torr. In one embodiment, the pressure is from about 0.2 torr to about 2 torr. In one embodiment, the pressure is about 0.2 torr. In one embodiment, the pressure is about 0.5 torr. In one embodiment, the pressure is about 1 torr. In one embodiment, the pressure is about 1.5 torr. In one embodiment, the pressure is about 2 torr. In one embodiment, the pressure is about 2.5 torr. In one embodiment, the pressure is about 5 torr. In one embodiment, the pressure is about 10 torr. In one embodiment, the pressure is about 15 torr. In one embodiment, the pressure is about 20 torr. In one embodiment, the pressure is about 25 torr. In one embodiment, the pressure is about 30 torr. In one embodiment, the pressure is about 40 torr. In one embodiment, the pressure is about 50 torr. In one embodiment, the pressure is about 60 torr. In one embodiment, the pressure is about 75 torr. In one embodiment, the pressure is about 100 torr.

[0063] (d) Exemplary Step (i) In one exemplary embodiment of the first surface modification of step (i), and as shown in Figure 1, the ZrO2 surface is exposed to tungsten hexafluoride (WF6), thereby converting solid ZrO2 to solid ZrF4 (i.e., ZrO2(s) + WF6(g) → ZrF4(s) + WO2F2(g)). In one aspect of the exemplary embodiment, and as previously described, this step may result in some W residue / by-products.

[0064] Step (ii) First Purge The first purge of step (ii) may use any suitable inert purge gas. In one embodiment, the purge gas comprises argon. In one embodiment, the purge gas comprises nitrogen.

[0065] time In one embodiment, the first purge time of step (ii) is from about 0.5 seconds to about 30 seconds. In one embodiment, the first purge time of step (ii) is from about 0.5 seconds to about 10 seconds. In one embodiment, the first purge time of step (ii) is from about 1 second to about 7 seconds. In one embodiment, the first purge time of step (ii) is from about 7 seconds to about 10 seconds. In one embodiment, the first purge time of step (ii) is from about 10 seconds to about 20 seconds. In one embodiment, the first purge time of step (ii) is from about 20 seconds to about 30 seconds. In one embodiment, the first purge time of step (ii) is from about 30 seconds to about 60 seconds. In one embodiment, the first purge time of step (ii) is about 0.25 seconds. In one embodiment, the first purge time of step (ii) is about 0.5 seconds. In one embodiment, the first purge time of step (ii) is about 1 second. In one embodiment, the first purge time of step (ii) is about 2 seconds. In one embodiment, the first purge time of step (ii) is about 3 seconds. In one embodiment, the first purge time of step (ii) is about 4 seconds. In one embodiment, the first purge time of step (ii) is about 5 seconds. In one embodiment, the first purge time of step (ii) is about 6 seconds. In one embodiment, the first purge time of step (ii) is about 7 seconds. In one embodiment, the first purge time of step (ii) is about 8 seconds. In one embodiment, the first purge time of step (ii) is about 9 seconds. In one embodiment, the first purge time of step (ii) is about 10 seconds. In one embodiment, the first purge time of step (ii) is about 12 seconds. In one embodiment, the first purge time exposure in step (ii) is about 15 seconds. In one embodiment, the first purge time exposure in step (ii) is about 17 seconds. In one embodiment, the first purge time exposure in step (ii) is about 20 seconds. In one embodiment, the first purge time exposure in step (ii) is about 25 seconds. In one embodiment, the first purge time exposure in step (ii) is about 30 seconds. In one embodiment, the first purge time exposure in step (ii) is about 35 seconds.In one embodiment, the first purge time in step (ii) is about 40 seconds. In one embodiment, the first purge time in step (ii) is about 50 seconds. In one embodiment, the first purge time in step (ii) is about 60 seconds.

[0066] flow rate In one embodiment, the first purge gas is flowed at about 100 sccm to about 5000 sccm. In one embodiment, the first purge gas is flowed at about 500 sccm to about 2500 sccm. In one embodiment, the first purge gas is flowed at about 1000 sccm to about 2000 sccm. In one embodiment, the first purge gas is flowed at about 100 sccm. In one embodiment, the first purge gas is flowed at about 200 sccm. In one embodiment, the first purge gas is flowed at about 300 sccm. In one embodiment, the first purge gas is flowed at about 400 sccm. In one embodiment, the first purge gas is flowed at about 500 sccm. In one embodiment, the first purge gas is flowed at about 1000 sccm. In one embodiment, the first purge gas is flowed at about 1500 sccm. In one embodiment, the first purge gas is flowed at about 2000 sccm. In one embodiment, the first purge gas is flowed at about 2500 sccm. In one embodiment, the first purge gas is flowed at about 3000 sccm. In one embodiment, the first purge gas is flowed at about 3500 sccm. In one embodiment, the first purge gas is flowed at about 4000 sccm. In one embodiment, the first purge gas is flowed at about 4500 sccm. In one embodiment, the first purge gas is flowed at about 5000 sccm.

[0067] pressure The first purge step of step (ii) can be performed at any suitable chamber pressure. In one embodiment, the pressure is from about 0.05 torr to about 5 torr. In one embodiment, the pressure is from about 1 torr to about 5 torr. In one embodiment, the pressure is from about 1 torr to about 2 torr. In one embodiment, the pressure is between about 0.5 torr and about 5 torr. In one embodiment, the pressure is from about 0.05 torr to about 2 torr. In one embodiment, the pressure is about 0.05 torr. In one embodiment, the pressure is about 0.1 torr. In one embodiment, the pressure is about 0.2 torr. In one embodiment, the pressure is about 0.5 torr. In one embodiment, the pressure is about 1 torr. In one embodiment, the pressure is about 1.5 torr. In one embodiment, the pressure is about 2 torr. In one embodiment, the pressure is about 2.5 torr. In one embodiment, the pressure is about 5 torr.

[0068] Step (iii) Ligand exchange In step (iii), ligand exchange, the fluorinated metal surface is exposed to one or more chlorine ligand donors for a period of time sufficient to displace (i.e., exchange) fluoride ions with chlorine and generate volatile chlorinated metal species.

[0069] (a) Ligand The chlorine ligand donor comprises one or more chlorine ligand donors capable of exchanging fluoride ions for chloride ions. In one aspect of this embodiment, the one or more chlorine ligand donors comprise one or more of dimethylaluminum chloride (DMAC, Al(CH3)2Cl), diethylaluminum chloride (DEAC, Al(C2H5)2Cl), titanium tetrachloride (TiCl4), boron trichloride (BCl3), and combinations thereof. In one aspect of this embodiment, the one or more chlorine ligand donors comprise DMAC. In one aspect of this embodiment, the one or more chlorine ligand donors comprise DEAC. In one aspect of this embodiment, the one or more chlorine ligand donors comprise TiCl4. In one aspect of this embodiment, the one or more chlorine ligand donors comprise BCl3. In one aspect of this embodiment, the one or more chlorine ligand donors comprise a combination of two or more of DMAC, DEAC, TiCl4, and BCl3. As one skilled in the art would appreciate, DMAC, DEAC, and TiCl4 are each considered to be non-corrosive chlorinating agents. In this regard, it is preferred that the chlorine ligand donor is a non-corrosive chlorinating agent, such as DMAC, DEAC, and / or TiCl4.

[0070] However, as one skilled in the art will appreciate, the chlorine ligand donor may alternatively or additionally comprise one or more more aggressive / more corrosive chlorinating agents, such as chlorine (Cl2), boron trichloride (BCl3), or thionyl chloride (SOCl2). While the use of more corrosive chlorine ligand donors is considered part of the disclosed and claimed invention, these materials are generally not preferred for use in the disclosed and claimed methods due to their corrosive nature. Thus, in another embodiment, the chlorinating agent is substantially free of corrosive chlorine ligand donors. In another embodiment, the chlorinating agent is substantially free of Cl2. In another embodiment, the chlorinating agent is substantially free of BCl3. In another embodiment, the chlorinating agent is substantially free of SOCl2. In another embodiment, the chlorinating agent is free of corrosive chlorine ligand donors. In another embodiment, the chlorinating agent is free of Cl2. In another embodiment, the chlorinating agent is free of BCl3. In another embodiment, the chlorinating agent is free of SOCl2. In another embodiment, the chlorinating agent is free of corrosive chlorine ligand donors. In another embodiment, the chlorinating agent is free of Cl2. In another embodiment, the chlorinating agent is free of BCl3. In another embodiment, the chlorinating agent is free of SOCl2.

[0071] (b) Conditions time In one embodiment, the ligand exchange time in step (iii) is from about 0.5 seconds to about 30 seconds. In one embodiment, the ligand exchange time in step (iii) is from about 0.5 seconds to about 10 seconds. In one embodiment, the ligand exchange time in step (iii) is from about 1 second to about 7 seconds. In one embodiment, the ligand exchange time in step (iii) is from about 7 seconds to about 10 seconds. In one embodiment, the ligand exchange time in step (iii) is from about 10 seconds to about 20 seconds. In one embodiment, the ligand exchange time in step (iii) is from about 20 seconds to about 30 seconds. In one embodiment, the ligand exchange time in step (iii) is about 0.25 seconds. In one embodiment, the ligand exchange time in step (iii) is about 0.5 seconds. In one embodiment, the ligand exchange time in step (iii) is about 1 second. In one embodiment, the ligand exchange time in step (iii) is about 2 seconds. In one embodiment, the ligand exchange time in step (iii) is about 3 seconds. In one embodiment, the ligand exchange time in step (iii) is about 4 seconds. In one embodiment, the ligand exchange time in step (iii) is about 5 seconds. In one embodiment, the ligand exchange time in step (iii) is about 6 seconds. In one embodiment, the ligand exchange time in step (iii) is about 7 seconds. In one embodiment, the ligand exchange time in step (iii) is about 8 seconds. In one embodiment, the ligand exchange time in step (iii) is about 9 seconds. In one embodiment, the ligand exchange time in step (iii) is about 10 seconds. In one embodiment, the ligand exchange time in step (iii) is about 12 seconds. In one embodiment, the ligand exchange time in step (iii) is about 15 seconds. In one embodiment, the ligand exchange time in step (iii) is about 17 seconds. In one embodiment, the ligand exchange time in step (iii) is about 20 seconds. In one embodiment, the ligand exchange time in step (iii) is about 25 seconds. In one embodiment, the ligand exchange time in step (iii) is about 30 seconds.

[0072] Ligand exchanger flow rate In one embodiment, the ligand exchange agent is flowed at about 1 sccm to about 500 sccm. In one embodiment, the ligand exchange agent is flowed at about 5 sccm to about 500 sccm. In one embodiment, the ligand exchange agent is flowed at about 0.5 sccm to about 100 sccm. In one embodiment, the ligand exchange agent is flowed at about 1 sccm to about 50 sccm. In one embodiment, the ligand exchange agent is flowed at about 5 sccm to about 25 sccm. In one embodiment, the ligand exchange agent is flowed at about 10 sccm to about 20 sccm. In one embodiment, the ligand exchange agent is flowed at about 15 sccm to about 25 sccm. In one embodiment, the ligand exchange agent is flowed at about 5 sccm. In one embodiment, the ligand exchange agent is flowed at about 10 sccm. In one embodiment, the ligand exchange agent is flowed at about 15 sccm. In one embodiment, the ligand exchange agent is flowed at about 20 sccm. In one embodiment, the ligand exchange agent is flowed at about 25 sccm. In one embodiment, the ligand exchange agent is flowed at about 30 sccm. In one embodiment, the ligand exchange agent is flowed at about 35 sccm. In one embodiment, the ligand exchange agent is flowed at about 40 sccm. In one embodiment, the ligand exchange agent is flowed at about 45 sccm. In one embodiment, the ligand exchange agent is flowed at about 50 sccm. In one embodiment, the ligand exchange agent is flowed at about 60 sccm. In one embodiment, the ligand exchange agent is flowed at about 70 sccm. In one embodiment, the ligand exchange agent is flowed at about 80 sccm. In one embodiment, the ligand exchange agent is flowed at about 90 sccm. In one embodiment, the ligand exchange agent is flowed at about 100 sccm. In one embodiment, the ligand exchange agent is flowed at about 125 sccm. In one embodiment, the ligand exchange agent is flowed at about 150 sccm. In one embodiment, the ligand exchange agent is flowed at about 200 sccm. In one embodiment, the ligand exchange agent is flowed at about 250 sccm. In one embodiment, the ligand exchange agent is flowed at about 300 sccm. In one embodiment, the ligand exchange agent is flowed at about 350 sccm. In one embodiment, the ligand exchange agent is flowed at about 400 sccm. In one embodiment, the ligand exchange agent is flowed at about 450 sccm.In one embodiment, the ligand exchange agent is flowed at about 500 sccm.

[0073] In one embodiment, the ligand exchange agent is provided alone.

[0074] In one embodiment, the ligand exchange agent is delivered using a suitable carrier gas. In one embodiment, the carrier gas comprises argon. In one embodiment, the carrier gas comprises nitrogen.

[0075] pressure The ligand exchange in step (iii) can be carried out at any suitable chamber pressure. In one embodiment, the pressure is from about 0.5 torr to about 100 torr. The ligand exchange in step (iii) can be carried out at any suitable chamber pressure. In one embodiment, the pressure is from about 5 torr to about 100 torr. In one embodiment, the pressure is from about 0.5 torr to about 15 torr. In one embodiment, the pressure is from about 1 torr to about 12 torr. In one embodiment, the pressure is from about 1 torr to about 10 torr. In one embodiment, the pressure is from about 1 torr to about 5 torr. In one embodiment, the pressure is from about 1 torr to about 2 torr. In one embodiment, the pressure is from about 0.5 torr to about 5 torr. In one embodiment, the pressure is from about 0.2 torr to about 2 torr. In one embodiment, the pressure is about 0.2 torr. In one embodiment, the pressure is about 0.5 torr. In one embodiment, the pressure is about 1 torr. In one embodiment, the pressure is about 1.5 torr. In one embodiment, the pressure is about 2 torr. In one embodiment, the pressure is about 2.5 torr. In one embodiment, the pressure is about 5 torr. In one embodiment, the pressure is about 10 torr. In one embodiment, the pressure is about 15 torr. In one embodiment, the pressure is about 20 torr. In one embodiment, the pressure is about 25 torr. In one embodiment, the pressure is about 30 torr. In one embodiment, the pressure is about 40 torr. In one embodiment, the pressure is about 50 torr. In one embodiment, the pressure is about 60 torr. In one embodiment, the pressure is about 75 torr. In one embodiment, the pressure is about 100 torr.

[0076] (d) Exemplary Step (iii) In one exemplary embodiment of the ligand exchange of step (iii), and as shown in FIG. 1, a layer of ZrF on the surface of ZrO (as described above) undergoes ligand exchange with dimethylaluminum chloride (DMAC, Al(CH3)2Cl) to produce volatile ZrCl4 and dimethylaluminum fluoride (DMAF, Al(CH3)2F) (i.e., ZrF4(s)+4Al(CH3)2Cl(g)→ZrCl4(g)+4Al(CH3)2F(g)).

[0077] Step (iv) Second Purge Any suitable inert purge gas can be used in the second purge of step (iv). In one embodiment, the purge gas comprises argon. In one embodiment, the purge gas comprises nitrogen.

[0078] time In one embodiment, the second purge time of step (iv) is from about 0.5 seconds to about 30 seconds. In one embodiment, the second purge time of step (iv) is from about 0.5 seconds to about 10 seconds. In one embodiment, the second purge time of step (iv) is from about 1 second to about 7 seconds. In one embodiment, the second purge time of step (iv) is from about 7 seconds to about 10 seconds. In one embodiment, the second purge time of step (iv) is from about 10 seconds to about 20 seconds. In one embodiment, the second purge time of step (iv) is from about 20 seconds to about 30 seconds. In one embodiment, the second purge time of step (iv) is from about 30 seconds to about 60 seconds. In one embodiment, the second purge time of step (iv) is about 0.25 seconds. In one embodiment, the second purge time of step (iv) is about 0.5 seconds. In one embodiment, the second purge time of step (iv) is about 1 second. In one embodiment, the second purge time of step (iv) is about 2 seconds. In one embodiment, the second purge time of step (iv) is about 3 seconds. In one embodiment, the second purge time of step (iv) is about 4 seconds. In one embodiment, the second purge time of step (iv) is about 5 seconds. In one embodiment, the second purge time of step (iv) is about 6 seconds. In one embodiment, the second purge time of step (iv) is about 7 seconds. In one embodiment, the second purge time of step (iv) is about 8 seconds. In one embodiment, the second purge time of step (iv) is about 9 seconds. In one embodiment, the second purge time of step (iv) is about 10 seconds. In one embodiment, the second purge time of step (iv) is about 12 seconds. In one embodiment, the second purge time of step (iv) is about 15 seconds. In one embodiment, the second purge time of step (iv) is about 17 seconds. In one embodiment, the second purge time of step (iv) is about 20 seconds. In one embodiment, the second purge time of step (iv) is about 25 seconds. In one embodiment, the second purge time of step (iv) is about 30 seconds. In one embodiment, the second purge time of step (iv) is about 35 seconds.In one embodiment, the second purge time of step (iv) is about 40 seconds. In one embodiment, the second purge time of step (iv) is about 50 seconds. In one embodiment, the second purge time of step (iv) is about 60 seconds.

[0079] flow rate In one embodiment, the second purge gas is flowed at about 100 sccm to about 5000 sccm. In one embodiment, the second purge gas is flowed at about 500 sccm to about 2500 sccm. In one embodiment, the second purge gas is flowed at about 1000 sccm to about 2000 sccm. In one embodiment, the second purge gas is flowed at about 100 sccm. In one embodiment, the second purge gas is flowed at about 200 sccm. In one embodiment, the second purge gas is flowed at about 300 sccm. In one embodiment, the second purge gas is flowed at about 400 sccm. In one embodiment, the second purge gas is flowed at about 500 sccm. In one embodiment, the second purge gas is flowed at about 1000 sccm. In one embodiment, the second purge gas is flowed at about 1500 sccm. In one embodiment, the second purge gas is flowed at about 2000 sccm. In one embodiment, the second purge gas is flowed at about 2500 sccm. In one embodiment, the second purge gas is flowed at about 3000 sccm. In one embodiment, the second purge gas is flowed at about 3500 sccm. In one embodiment, the second purge gas is flowed at about 4000 sccm. In one embodiment, the second purge gas is flowed at about 4500 sccm. In one embodiment, the second purge gas is flowed at about 5000 sccm.

[0080] pressure The second purge step of step (iv) can be performed at any suitable chamber pressure. In one embodiment, the pressure is from about 0.05 torr to about 5 torr. In one embodiment, the pressure is from about 1 torr to about 5 torr. In one embodiment, the pressure is between about 1 torr and about 2 torr. In one embodiment, the pressure is between about 0.5 torr to about 5 torr. In one embodiment, the pressure is between about 0.05 torr and about 2 torr. In one embodiment, the pressure is about 0.05 torr. In one embodiment, the pressure is about 0.1 torr. In one embodiment, the pressure is about 0.2 torr. In one embodiment, the pressure is about 0.5 torr. In one embodiment, the pressure is about 1 torr. In one embodiment, the pressure is about 1.5 torr. In one embodiment, the pressure is about 2 torr. In one embodiment, the pressure is about 2.5 torr. In one embodiment, the pressure is about 5 torr.

[0081] Step (v) Second Surface Modification The second surface modification of step (v) involves exposing the etched metal oxide surface to one or more oxidizing agents for a period of time sufficient to oxidize metal by-products present on the etched metal surface to species that are readily volatilizable upon exposure to the fluorinating agent when step (i) is repeated during the next cycle. As noted above, for example, when WF6 is used as the fluorinating agent, this results in W species (e.g., WO x , x is between about 2 and about 3), which contaminates the surface and, over time, slows or stops the etching process. The oxidation step converts these by-products to WO3, which can be easily reacted and removed upon exposure to a fluorinating agent when step (i) is repeated during the next cycle.

[0082] In one aspect, the one or more oxidizing agents include one or more of oxygen (O2), ozone (O3), nitric oxide (NO), water (H2O) vapor, hydrogen peroxide (H2O2), oxygen plasma (O*), and combinations thereof. In one aspect of this aspect, the one or more oxidizing agents include oxygen. In one aspect of this aspect, the one or more oxidizing agents include ozone. In one aspect of this aspect, the one or more oxidizing agents include nitric oxide. In one aspect of this aspect, the one or more oxidizing agents include water vapor. In one aspect of this aspect, the one or more oxidizing agents include hydrogen peroxide. In one aspect of this aspect, the one or more oxidizing agents include oxygen and ozone. In one aspect of this aspect, the one or more oxidizing agents include oxygen plasma. In one aspect of this aspect, the one or more oxidizing agents include oxygen plasma. In one aspect, the one or more oxidizing agents are steam.

[0083] In one embodiment, exposing the etched metal oxide surface to one or more oxidizing agents comprises sequential exposure to a first oxidizing agent followed by exposure to a second oxidizing agent different from the first oxidizing agent, In one aspect of this embodiment, the first oxidizing agent is one of oxygen and ozone, and the second oxidizing agent is the other of oxygen and ozone.

[0084] (b) Conditions time In one embodiment, the oxidant flow time in step (v) is from about 0.5 seconds to about 30 seconds. In one embodiment, the oxidant flow time in step (v) is from about 0.5 seconds to about 10 seconds. In one embodiment, the oxidant flow time in step (v) is from about 1 second to about 7 seconds. In one embodiment, the oxidant flow time in step (v) is from about 7 seconds to about 10 seconds. In one embodiment, the oxidant flow time in step (v) is from about 10 seconds to about 20 seconds. In one embodiment, the oxidant flow time in step (v) is from about 20 seconds to about 30 seconds. In one embodiment, the oxidant flow time in step (v) is from about 30 seconds to about 60 seconds. In one embodiment, the oxidant flow time in step (v) is from about 1 second to about 60 seconds. In one embodiment, the oxidant flow time in step (v) is about 0.25 seconds. In one embodiment, the oxidant flow time in step (v) is about 0.5 seconds. In one embodiment, the oxidant flow time in step (v) is about 1 second. In one embodiment, the oxidant flow time in step (v) is about 2 seconds. In one embodiment, the oxidant flow time in step (v) is about 3 seconds. In one embodiment, the oxidant flow time in step (v) is about 4 seconds. In one embodiment, the oxidant flow time in step (v) is about 5 seconds. In one embodiment, the oxidant flow time in step (v) is about 6 seconds. In one embodiment, the oxidant flow time in step (v) is about 7 seconds. In one embodiment, the oxidant flow time in step (v) is about 8 seconds. In one embodiment, the oxidant flow time in step (v) is about 9 seconds. In one embodiment, the oxidant flow time in step (v) is about 10 seconds. In one embodiment, the oxidant flow time in step (v) is about 12 seconds. In one embodiment, the oxidant flow time exposure in step (v) is about 15 seconds. In one embodiment, the oxidant flow time in step (v) is about 17 seconds. In one embodiment, the oxidant flow time in step (v) is about 20 seconds. In one embodiment, the oxidant flow time in step (v) is about 25 seconds. In one embodiment, the oxidant flow time in step (v) is about 30 seconds. In one embodiment, the oxidant flow time in step (v) is about 35 seconds.In one embodiment, the oxidant flow time in step (v) is about 40 seconds. In one embodiment, the oxidant flow time in step (v) is about 50 seconds. In one embodiment, the oxidant flow time in step (v) is about 60 seconds.

[0085] flow rate In one embodiment, the oxidizer is flowed at about 50 sccm to about 3000 sccm. In one embodiment, the oxidizer is flowed at about 10 sccm to about 1000 sccm. In one embodiment, the oxidizer is flowed at about 500 sccm to about 1000 sccm. In one embodiment, the oxidizer is flowed at about 1000 sccm to about 2000 sccm. In one embodiment, the oxidizer is flowed at about 50 sccm. In one embodiment, the oxidizer is flowed at about 75 sccm. In one embodiment, the oxidizer is flowed at about 100 sccm. In one embodiment, the oxidizer is flowed at about 200 sccm. In one embodiment, the oxidizer is flowed at about 300 sccm. In one embodiment, the oxidizer is flowed at about 400 sccm. In one embodiment, the oxidizer is flowed at about 500 sccm. In one embodiment, the oxidizer is flowed at about 1000 sccm. In one embodiment, the oxidizer is flowed at about 1500 sccm. In one embodiment, the oxidizer is flowed at about 2000 sccm. In one embodiment, the oxidizer is flowed at about 2500 sccm. In one embodiment, the oxidizer is flowed at about 3000 sccm.

[0086] In one embodiment, the oxidizing agent is provided alone.

[0087] In one embodiment, the oxidant is delivered using a suitable carrier gas. In one embodiment, the carrier gas comprises argon. In one embodiment, the carrier gas comprises nitrogen.

[0088] pressure The oxidation step of step (v) can be performed at any suitable chamber pressure. In one embodiment, the pressure is from about 0.5 torr to about 100 torr. The oxidation step of step (v) can be performed at any suitable chamber pressure. In one embodiment, the pressure is from about 5 torr to about 100 torr. In one embodiment, the pressure is from about 0.5 torr to about 15 torr. In one embodiment, the pressure is from about 1 torr to about 12 torr. In one embodiment, the pressure is from about 1 torr to about 10 torr. In one embodiment, the pressure is from about 1 torr to about 5 torr. In one embodiment, the pressure is from about 1 torr to about 2 torr. In one embodiment, the pressure is from about 0.5 torr to about 5 torr. In one embodiment, the pressure is from about 0.2 torr to about 2 torr. In one embodiment, the pressure is about 0.2 torr. In one embodiment, the pressure is about 0.5 torr. In one embodiment, the pressure is about 1 torr. In one embodiment, the pressure is about 1.5 torr. In one embodiment, the pressure is about 2 torr. In one embodiment, the pressure is about 2.5 torr. In one embodiment, the pressure is about 5 torr. In one embodiment, the pressure is about 10 torr. In one embodiment, the pressure is about 15 torr. In one embodiment, the pressure is about 20 torr. In one embodiment, the pressure is about 25 torr. In one embodiment, the pressure is about 30 torr. In one embodiment, the pressure is about 40 torr. In one embodiment, the pressure is about 50 torr. In one embodiment, the pressure is about 60 torr. In one embodiment, the pressure is about 75 torr. In one embodiment, the pressure is about 100 torr.

[0089] (d) Exemplary Step (v) In one exemplary embodiment of the second surface modification of step (v) and as shown in FIG. 1, the etched metal oxide surface is exposed to an oxidizing agent, thereby converting surface W species, which may be partially oxidized, fluorinated, chlorinated or methylated, to a more oxidized form of W, e.g., WO, where the oxidizing agent can be O, O, oxygen plasma, nitric oxide, HO, or HO (i.e., WOx F y Cl z (CH3) n (s)+[O2, O3, O*, NO, H2O, H2O2]→WO3(s)) 。

[0090] Step (vi) Third purge Any suitable inert purge gas can be used in the third purge of step (vi). In one embodiment, the purge gas comprises argon. In one embodiment, the purge gas comprises nitrogen.

[0091] time In one embodiment, the third purge time of step (vi) is from about 0.5 seconds to about 30 seconds. In one embodiment, the third purge time of step (vi) is from about 0.5 seconds to about 10 seconds. In one embodiment, the third purge time of step (vi) is from about 1 second to about 7 seconds. In one embodiment, the third purge time of step (vi) is from about 7 seconds to about 10 seconds. In one embodiment, the third purge time of step (vi) is from about 10 seconds to about 20 seconds. In one embodiment, the third purge time of step (vi) is from about 20 seconds to about 30 seconds. In one embodiment, the third purge time of step (vi) is from about 30 seconds to about 60 seconds. In one embodiment, the third purge time of step (vi) is from about 60 seconds to about 120 seconds. In one embodiment, the third purge time of step (vi) is about 0.25 seconds. In one embodiment, the third purge time of step (vi) is about 0.5 seconds. In one embodiment, the third purge time of step (vi) is about 1 second. In one embodiment, the third purge time of step (vi) is about 2 seconds. In one embodiment, the third purge time of step (vi) is about 3 seconds. In one embodiment, the third purge time of step (vi) is about 4 seconds. In one embodiment, the third purge time of step (vi) is about 5 seconds. In one embodiment, the third purge time of step (vi) is about 6 seconds. In one embodiment, the third purge time of step (vi) is about 7 seconds. In one embodiment, the third purge time of step (vi) is about 8 seconds. In one embodiment, the third purge time of step (vi) is about 9 seconds. In one embodiment, the third purge time of step (vi) is about 10 seconds. In one embodiment, the third purge time of step (vi) is about 12 seconds. In one embodiment, the third purge time exposure of step (vi) is about 15 seconds. In one embodiment, the third purge time of step (vi) is about 17 seconds. In one embodiment, the third purge time of step (vi) is about 20 seconds. In one embodiment, the third purge time of step (vi) is about 25 seconds. In one embodiment, the third purge time of step (vi) is about 30 seconds.In one embodiment, the third purge time of step (vi) is about 35 seconds. In one embodiment, the third purge time of step (vi) is about 40 seconds. In one embodiment, the third purge time of step (vi) is about 50 seconds. In one embodiment, the third purge time of step (vi) is about 60 seconds. In one embodiment, the third purge time of step (vi) is about 75 seconds. In one embodiment, the third purge time of step (vi) is about 90 seconds. In one embodiment, the third purge time of step (vi) is about 120 seconds.

[0092] flow rate In one embodiment, the third purge gas is flowed at about 100 sccm to about 5000 sccm. In one embodiment, the third purge gas is flowed at about 500 sccm to about 2500 sccm. In one embodiment, the third purge gas is flowed at about 1000 sccm to about 2000 sccm. In one embodiment, the third purge gas is flowed at about 100 sccm. In one embodiment, the third purge gas is flowed at about 200 sccm. In one embodiment, the third purge gas is flowed at about 300 sccm. In one embodiment, the third purge gas is flowed at about 400 sccm. In one embodiment, the third purge gas is flowed at about 500 sccm. In one embodiment, the third purge gas is flowed at about 1000 sccm. In one embodiment, the third purge gas is flowed at about 1500 sccm. In one embodiment, the third purge gas is flowed at about 2000 sccm. In one embodiment, the third purge gas is flowed at about 2500 sccm. In one embodiment, the third purge gas is flowed at about 3000 sccm. In one embodiment, the third purge gas is flowed at about 3500 sccm. In one embodiment, the third purge gas is flowed at about 4000 sccm. In one embodiment, the third purge gas is flowed at about 4500 sccm. In one embodiment, the third purge gas is flowed at about 5000 sccm.

[0093] pressure The third purge step of step (vi) can be performed at any suitable chamber pressure. In one embodiment, the pressure is from about 0.05 torr to about 5 torr. In one embodiment, the pressure is from about 1 torr to about 5 torr. In one embodiment, the pressure is from about 1 torr to about 2 torr. In one embodiment, the pressure is from about 0.5 torr to about 5 torr. In one embodiment, the pressure is from about 0.05 torr to about 2 torr. In one embodiment, the pressure is about 0.05 torr. In one embodiment, the pressure is about 0.1 torr. In one embodiment, the pressure is about 0.2 torr. In one embodiment, the pressure is about 0.5 torr. In one embodiment, the pressure is about 1 torr. In one embodiment, the pressure is about 1.5 torr. In one embodiment, the pressure is about 2 torr. In one embodiment, the pressure is about 2.5 torr. In one embodiment, the pressure is about 5 torr.

[0094] Post-ALE Processing As previously described, the disclosed and claimed methods may further include a post-treatment as an optional step (vii) to remove impurities remaining on the metal oxide surface after multiple cycles. In one aspect of this embodiment, the optional post-treatment as step (vii) includes treating the metal oxide surface with one or more oxidizing agents for a desired period of time (e.g., about 10 seconds to about 500 seconds). In one aspect of this embodiment, the optional post-treatment as step (vii) includes treating the metal oxide surface with one or more of oxygen (O2) and ozone (O3) for a desired period of time (e.g., about 10 seconds to about 500 seconds). In one aspect of this embodiment, the optional post-treatment as step (vii) includes treating the metal oxide surface with oxygen (O2). In one aspect of this embodiment, the optional post-treatment as step (vii) includes treating the metal oxide surface with ozone (O3). Examples of optional post-treatment as step (vii) are described below in the Examples.

[0095] Chamber (reactor) temperature External Heater In one embodiment, the chamber external heater is set at about 100° C. to about 200° C. In one embodiment, the chamber external heater is set at about 100° C. In one embodiment, the chamber external heater is set at about 120° C. In one embodiment, the chamber external heater is set at about 140° C. In one embodiment, the chamber external heater is set at about 160° C. In one embodiment, the chamber external heater is set at about 180° C. In one embodiment, the chamber external heater is set at about 200° C.

[0096] Lid heater (i.e., process chamber gas delivery zone) In one embodiment, the chamber lid heater is set at about 100° C. to about 200° C. In one embodiment, the chamber lid heater is set at about 100° C. In one embodiment, the chamber lid heater is set at about 130° C. In one embodiment, the chamber lid heater is set at about 150° C. In one embodiment, the chamber lid heater is set at about 200° C.

[0097] Internal heater (i.e. process chamber or sample pedestal) In one embodiment, the internal chamber heater is set at about 100° C. to about 400° C. In one embodiment, the internal chamber heater is set at about 100° C. In one embodiment, the internal chamber heater is set at about 150° C. In one embodiment, the internal chamber heater is set at about 200° C. In one embodiment, the internal chamber heater is set at about 250° C. In one embodiment, the internal chamber heater is set at about 300° C. In one embodiment, the internal chamber heater is set at about 350° C. In one embodiment, the internal chamber heater is set at about 400° C.

[0098] Film properties The disclosed and claimed invention further includes films formed by the methods described herein.

[0099] Film Aspect Ratio In one embodiment, a film etched by the methods described herein has trenches, vias, or other topographical features with an aspect ratio of about 0 to about 60. In yet another aspect of this embodiment, the aspect ratio is about 1 to about 10. In yet another aspect of this embodiment, the aspect ratio is about 10 to 100. In yet another aspect of this embodiment, the aspect ratio is about 0. In yet another aspect of this embodiment, the aspect ratio is about 1. In yet another aspect of this embodiment, the aspect ratio is about 2. In yet another aspect of this embodiment, the aspect ratio is about 5. In yet another aspect of this embodiment, the aspect ratio is about 10. In yet another aspect of this embodiment, the aspect ratio is about 20. In yet another aspect of this embodiment, the aspect ratio is about 30. In yet another aspect of this embodiment, the aspect ratio is about 40. In yet another aspect of this embodiment, the aspect ratio is about 50. In yet another aspect of this embodiment, the aspect ratio is about 60. In yet another aspect of this embodiment, the aspect ratio is about 80. In yet another aspect of this embodiment, the aspect ratio is about 100.

[0100] Dielectric constant In another embodiment, a film etched by the methods described herein has a dielectric constant between 5 and 10. In another embodiment, a film etched by the methods described herein has a dielectric constant between 10 and 30. In another embodiment, a film etched by the methods described herein has a dielectric constant between 30 and 50. In another embodiment, a film etched by the methods described herein has a dielectric constant between 50 and 80. In another embodiment, a film etched by the methods described herein has a dielectric constant of about 1.5. In another embodiment, a film etched by the methods described herein has a dielectric constant of about 2. In another embodiment, a film etched by the methods described herein has a dielectric constant of about 3. In another embodiment, a film etched by the methods described herein has a dielectric constant of about 4. In another embodiment, a film etched by the methods described herein has a dielectric constant of about 5. In another embodiment, a film etched by the methods described herein has a dielectric constant of about 6. In another embodiment, a film etched by the methods described herein has a dielectric constant of about 7. In another embodiment, a film etched by the methods described herein has a dielectric constant of about 8. In another embodiment, a film etched by the methods described herein has a dielectric constant of about 9. In another embodiment, a film etched by the methods described herein has a dielectric constant of about 10. In another embodiment, a film etched by the methods described herein has a dielectric constant of about 12. In another embodiment, a film etched by the methods described herein has a dielectric constant of about 14. In another embodiment, a film etched by the methods described herein has a dielectric constant of about 16. In another embodiment, a film etched by the methods described herein has a dielectric constant of about 18. In another embodiment, a film etched by the methods described herein has a dielectric constant of about 20. In another embodiment, a film etched by the methods described herein has a dielectric constant of about 25. In another embodiment, a film etched by the methods described herein has a dielectric constant of about 30.In another embodiment, a film etched by the methods described herein has a dielectric constant of about 35. In another embodiment, a film etched by the methods described herein has a dielectric constant of about 40. In another embodiment, a film etched by the methods described herein has a dielectric constant of about 45. In another embodiment, a film etched by the methods described herein has a dielectric constant of about 50. In another embodiment, a film etched by the methods described herein has a dielectric constant of about 55. In another embodiment, a film etched by the methods described herein has a dielectric constant of about 60. In another embodiment, a film etched by the methods described herein has a dielectric constant of about 65. In another embodiment, a film etched by the methods described herein has a dielectric constant of about 70. In another embodiment, a film etched by the methods described herein has a dielectric constant of about 75. In another embodiment, a film etched by the methods described herein has a dielectric constant of about 80.

[0101] Crystal structure In one embodiment, the film etched by the methods described herein is crystalline and has a desired crystal structure, such as a cubic structure, a tetragonal structure, an orthorhombic structure, or a non-centrosymmetric crystal structure, that comprises the majority of the film. In one embodiment, the cubic structure comprises the majority of the film composed of ZrO2, HfO2, a combination of HfO2 and ZrO2, or any of these materials including engineered impurities (i.e., dopants). In one embodiment, the tetragonal structure comprises the majority of the film composed of ZrO2, HfO2, a combination of HfO2 and ZrO2, or any of these materials including engineered impurities (i.e., dopants). In one embodiment, the orthorhombic structure comprises the majority of the film composed of ZrO2, HfO2, a combination of HfO2 and ZrO2, or any of these materials including engineered impurities (i.e., dopants). In one embodiment, the non-centrosymmetric crystal structure comprises the majority of a film composed of ZrO2, HfO2, a combination of HfO2 and ZrO2, or any of these materials including engineered impurities (i.e., dopants). In one embodiment, the desired crystal structure comprises from about 50% to about 90% of the film. In one embodiment, the desired crystal structure comprises from about 90% to about 95% of the film. In one embodiment, the desired crystal structure comprises from about 95% to about 100% of the film.

[0102] MIMcap device In another aspect, the disclosed and claimed invention relates to a metal-insulator-metal capacitor ("MIMcap") device comprising, consisting essentially of, or consisting of a first electrode, a dielectric layer formed using the disclosed and claimed ALE method, and a second electrode. In yet another aspect, the MIMcap device ideally exhibits a higher dielectric constant (k) and lower leakage current than an otherwise equivalent MIMcap fabricated without the disclosed and claimed ALE method, where the dielectric constant (k) can also be expressed as the equivalent equivalent oxide thickness (EOT) of the silicon oxide dielectric layer that results in an equivalent capacitance.

[0103] In yet another aspect, the first electrode and the second electrode are independently selected from TiN, W, Ni, Ru, Pt, and Al.

[0104] In yet another aspect, the first electrode and the second electrode are TiN. In yet another aspect, the thickness of the starting dielectric layer before ALE is between about 5 nm and about 10 nm. In yet another aspect, the thickness of the etched dielectric layer is between about 1 nm and about 6 nm. Another aspect is the use of the disclosed and claimed metal-containing films or metal-containing films prepared by the disclosed and claimed methods as a dielectric layer in a metal-insulator-metal capacitor. EXAMPLES

[0105] 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.

[0106] 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 the following examples, is intended to cover modifications and variations of the disclosed invention that come within the scope of any claims and their equivalents.

[0107] Materials and Methods: In the following examples, the ALE process was carried out in an ALD system equipped with a heated showerhead lid. The ALD system can accommodate wafer sizes up to 12 inches in diameter. The ALD system has a heated pedestal on which the wafer is mounted. For each experiment, a 44 mm x 44 mm test substrate was placed on a 300 mm silicon carrier wafer.

[0108] Dimethylaluminum chloride (DMAC) was obtained from EMD Electronics. The standard temperature of the DMAC source for all conditions was 35° C. DMAC was administered in vapor draw mode for all tests.

[0109] In each experiment, the pedestal was heated to 30°C above the intended sample temperature to account for temperature gradients on the carrier wafer. A 100 sccm argon purge flow was run continuously throughout the process to protect the sensitive internal components of the chamber.

[0110] As these examples show, the ALE process can be easily controlled (i.e., tailored) to provide the amount of etching specific to a desired application.

[0111] Examples 1-3: Zirconium oxide ALE using DMAC, WF6 and O2 Test substrates were prepared by atomic layer deposition (ALD) of approximately 93-95 Å of zirconium oxide on a 300 mm silicon wafer coated with approximately 50 Å of titanium nitride. The second 300 mm wafer was then cleaved into test substrates, each 44 mm by 44 mm. Each test substrate was annealed at 500° C. for 10 minutes in Ar prior to etching.

[0112] ALE was performed over 24 to 50 cycles with the process chamber pedestal heater set at either 280°C, 330°C or 380°C (corresponding to expected sample temperatures of approximately 250°C, 300°C or 350°C), and the process chamber lid heater set at 130°C and the showerhead heater set at 140°C, with each cycle containing a single dose of DMAC (preheated to 35°C), a single dose of WF6 and a single dose of O2, as follows:

[0113] [Table 1] After completion of the process, a surface treatment step of about 100 sccm ozone (O3) with about 400 sccm oxygen (O2) was performed for 60 seconds in the same chamber at the same pedestal temperature as the etching sequence.

[0114] The process described in this example removed ZrO2 as listed in Table 1.

[0115] [Table 2] Example 4: Zirconium oxide ALE using DMAC, WF6 and (O2+O3) Test substrates were prepared by atomic layer deposition (ALD) of about 91-95 Å of zirconium oxide on a second 300 mm silicon wafer that had been coated with about 50 Å of titanium nitride. The second 300 mm wafer was then cleaved into test substrates each measuring 44 mm by 44 mm. Each test substrate was annealed in Ar at 500° C. for 10 minutes prior to etching.

[0116] Using a process chamber pedestal heater setting of 380° C. (corresponding to an expected sample temperature of approximately 350° C.) and the process chamber lid heater set at 130° C. and the showerhead heater set at 140° C., ALE was performed over 24 cycles, each cycle including a single dose of DMAC (preheated to 35° C.), a single dose of WF6, and a single dose of a mixture of O2 and O3, as follows:

[0117] [Table 3] After completion of the process, a surface treatment step of about 20 sccm ozone (O3) with about 480 sccm oxygen (O2) was performed for 300 seconds in the same chamber at the same pedestal temperature as the etching sequence.

[0118] The process described in Example 4 removed 22-28 Å of ZrO2.

[0119] Example 5: Hafnium oxide ALE using DMAC, WF6 and (O2+O3) Test substrates were prepared by atomic layer deposition (ALD) of approximately 67-69 Å of hafnium oxide on a second 300 mm silicon wafer, which was then diced into test substrates each measuring 44 mm×44 mm.

[0120] Using a process chamber pedestal heater setting of 400° C. (corresponding to an expected sample temperature of approximately 370° C.) and the process chamber lid heater set at 130° C. and the showerhead heater set at 140° C., ALE was performed over 60 cycles, each cycle including a single dose of DMAC (preheated to 35° C.), a single dose of WF6, and a single dose of a mixture of O2 and O3, as follows:

[0121] [Table 4] After completion of the process, a surface treatment step of about 20 sccm ozone (O3) with about 480 sccm oxygen (O2) was performed for 300 seconds in the same chamber at the same pedestal temperature as the etching sequence.

[0122] The process described in Example 5 removed 25-29 Å of HfO2.

[0123] Example 6: (Hf,Zr)O2ALE using DMAC, WF6 and (O2+O3) The test substrate was a Hf ion implantation site of approximately 74-76 Å on a second 300 mm silicon wafer. 0.5 Zr 0.5 The second 300 mm wafer was then cut into test substrates each measuring 44 mm by 44 mm.

[0124] Using a process chamber pedestal heater setting of 400° C. (corresponding to an expected sample temperature of approximately 370° C.) and the process chamber lid heater set at 130° C. and the showerhead heater set at 140° C., ALE was performed over 60 cycles, each cycle including a single dose of DMAC (preheated to 35° C.), a single dose of WF6, and a single dose of a mixture of O2 and O3, as follows:

[0125] [Table 5] After completion of the process, a surface treatment step of about 20 sccm ozone (O3) with about 480 sccm oxygen (O2) was performed for 300 seconds in the same chamber at the same pedestal temperature as the etching sequence.

[0126] The process described in Example 6 is a process for forming Hf 0.5 Zr 0.5 O2 was removed.

[0127] Examples 7-8: TiN / ZrO2 / TiN MIMcap using ZrO2ALE Test substrates were prepared by atomic layer deposition (ALD) of zirconium oxide on a second 300 mm silicon wafer coated with approximately 50 Å of titanium nitride. The second 300 mm wafer was then cut into test substrates, each 44 mm by 44 mm. Each test substrate was annealed at 500° C. for 10 minutes in Ar prior to etching.

[0128] Using a process chamber pedestal heater at 380° C. (corresponding to an expected sample temperature of approximately 350° C.) and a process chamber lid heater set at 130° C. and a showerhead heater set at 140° C., ALE was performed over multiple cycles, with each cycle including a single dose of DMAC (preheated to 35° C.), a single dose of WF6, and a single dose of a mixture of O2 and O3, as follows:

[0129] [Table 6] After completion of the process, a surface treatment step of about 20 sccm ozone (O3) with about 480 sccm oxygen (O2) was performed for 300 seconds in the same chamber at the same pedestal temperature as the etching sequence. To complete the MIMcap device, the titanium nitride top electrode was deposited in a series of physical vapor deposition steps. The top electrode diameter ranged from about 250 μm to about 350 μm.

[0130] ZrO2 film thickness measurements and electrical device test results are shown in Table 2. For electrical results, the median value from multiple devices tested is reported. EOT refers to the equivalent oxide thickness of silicon oxide that provides equivalent dielectric performance to the measured MIMcap. In Example 7, use of the etching method described herein results in a MIMcap with a relatively low leakage current and a relatively low EOT relative to a comparative sample with the same ZrO2 thickness. In Example 8, use of the etching method described herein results in a MIMcap with a relatively low EOT but a relatively high leakage current relative to a comparative sample with a similar ZrO2 thickness, although it is generally expected that the leakage current will be greater as the EOT decreases.

[0131] [Table 7] 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 those 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. A thermal ALE method for etching the surface of a metal oxide substrate, comprising the following steps: (i) A first surface modification step comprising exposing the surface of the metal oxide substrate to one or more fluorinating agents to produce a fluorinated surface; (ii) A first purge step; (iii) A ligand exchange step comprising exposing the fluorinated surface to one or more chlorine ligand suppliers to produce volatile chlorinated species; (iv) A second purge step; (v) A second surface modification step comprising exposing the surface of the metal oxide substrate to one or more oxidizing agents to oxidize metal by-products; and (vi) A third purge step; The method comprising performing the steps.

2. wherein the metal oxide is ZrO ２ , HfO ２ , Hf ｘ Zr １－ｘ O ２ (wherein x is a value between 0 and 1), TiO ２ , Al ２ O ３ and the method according to claim 1, comprising one or more of these combinations.

3. The method according to claim 1, wherein in step (i), the one or more fluorinating agents comprise one or more metal fluorides.

4. In step (i), the one or more fluorinating agents include one or more of VF ５ , NbF ５ , TaF ５ , MoF ６ , WF ６ , ReF6, ReF ７ , AsF5, SbF5, and TeF6, the method according to claim 1.

5. The method according to claim 1, wherein in step (i), the exposure time of the one or more fluorinating agents to the surface of the metal oxide is from about 0.5 seconds to about 30 seconds.

6. The method according to claim 1, wherein step (i) is performed at a pressure from about 0.5 torr to about 100 torr.

7. In step (iii), the one or more chlorine ligand suppliers include dimethylaluminum chloride (DMAC; Al(CH ３ ), ２ Cl), diethylaluminum chloride (DEAC; Al(C ２ H ５ ), ２ Cl), titanium tetrachloride (TiCl ４ ), boron trichloride (BCl ３ ), and the method according to claim 1, comprising one or more of these combinations.

8. The method according to claim 1, wherein in step (iii), the exposure time of the one or more chlorine ligand suppliers to the surface of the metal oxide is from about 0.5 seconds to about 30 seconds.

9. The method according to claim 1, wherein step (iii) is performed at a pressure from about 0.5 torr to about 100 torr.

10. In step (v), the one or more oxidizing agents are oxygen (O ２ ), ozone (O ３ ), nitrogen monoxide (NO), water (H ２ O) vapor, hydrogen peroxide (H ２ O ２ ), oxygen plasma (O*), and one or more of combinations thereof, the method according to claim 1.

11. The method according to claim 1, wherein in step (v), the exposure time of the one or more oxidizing agents is from about 1 second to about 60 seconds.

12. The method according to claim 1, wherein step (v) is performed at a pressure from about 0.5 torr to about 100 torr.

13. A metal-containing film etched by the method according to any one of claims 1 to 12, the metal-containing film comprising a topographic pattern having an aspect ratio from about 0 to about 60.

14. A metal-containing film etched by the method according to any one of claims 1 to 12, the metal-containing film comprising a topographic pattern having an aspect ratio from about 10 to about 100.

15. A metal-containing film etched by the method according to any one of claims 1 to 12, the metal-containing film having a dielectric constant between about 1.5 and about 80.

16. A metal-containing film etched by the method according to any one of claims 1 to 12, the metal-containing film having a cubic crystal structure for the most part.

17. A metal-containing film etched by the method according to any one of claims 1 to 12, the metal-containing film having a tetragonal crystal structure for the most part.

18. A metal-containing film etched by the method according to any one of claims 1 to 12, the metal-containing film having an orthorhombic crystal structure for the most part.

19. A metal-containing film etched by the method according to any one of claims 1 to 12, the metal-containing film having a non-centrosymmetric crystal structure for the most part.

20. A metal-insulator-metal capacitor device including a first electrode, a dielectric layer, and a second electrode, the dielectric layer being manufactured by the method according to any one of claims 1 to 12.

21. The metal-insulator-metal capacitor device according to claim 20, wherein the dielectric layer has a thickness between about 5 nm and about 10 nm before etching and a thickness between about 1 nm and about 6 nm after etching.

22. Use of a metal-containing film etched by the method according to any one of claims 1 to 12 as a dielectric layer in a metal-insulator-metal capacitor.

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