WO2025129090A1 - Integrated process for metallization - Google Patents

Abstract

Integrated multi-step, seam-free, via metallization methods for precisely directed metal growth on copper in BEOL semiconductor manufacturing processes including a selective etch stop layer dry etch, selective inhibition of a metal-containing hardmask and selective molybdenum or tungsten deposition under vacuum are provided herein. Apparatuses for integrating the metallization operations in the same process chamber are also provided.

Description

INTEGRATED PROCESS FOR METALLIZATION

INCORPORATION BY REFERENCE

[0001] A PCT Request Form is filed concurrently with this specification as part of the present application. Each application that the present application claims benefit of or priority to as identified in the concurrently filed PCT Request Form is incorporated by reference herein in its entirety and for all purposes.

BACKGROUND

[0002] Semiconductor fabrication processes involve metallization during back-end-of-line (“BEOL”) processing for logic. Contacts may be formed by depositing conductive interconnect material in an opening on the surface of insulating material disposed between two spaced apart conductive layers. Interconnect materials may be made of aluminum or copper, although copper may provide a lower electrical resistivity than aluminum. However, copper suffers from diffusion resulting in the formation of undesirable intermetallic alloys, necessitating the use of barrier materials.

[0003] Copper interconnects may be made by a metal polishing process (dual damascene) rather than direct etching because of copper corrosion during the etch process. A challenge of dual damascene structure formation is to overlay the copper with a metal such as tungsten or molybdenum without either 1) the indiscriminate and unintended nucleation of metal onto other parts of the structure such as metal hardmask; or 2) corrosion of the copper and/or any protective copper overlay. As dimensions continue to shrink, especially beyond 7 nm mode, these issues become even more acute. Filling aggressive dual damascene openings and the liner occupying much of the interconnect space therefore compels a search for more effective means of metallization.

[0004] The background description provided herein is for the purposes of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

SUMMARY

[0005] Integrated seam-free via metallization methods for metal growth which can be specifically targeted for application to a conductive metal layer in BEOL semiconductor manufacturing processes are described. The in-situ multi-step process includes a selective etch stop layer dry etch, a selective inhibition of a metal-containing hardmask to prevent metal growth over the metal-containing hardmask, and a selective molybdenum or tungsten deposition performed under vacuum. Additionally, the conductive metal layer in the trench below the dual damascene contact structure may be capped to prevent corrosion. The methods allow the delivery of molybdenum or tungsten with pinpoint accuracy, and with avoidance of unwanted corrosion or contaminating byproducts. The methods may provide highly efficient metallization of a sub- 14 nm CD via in a dual damascene structure where a metal -containing hardmask is present on the field region of the structure. The selective dry etch may be a ligand exchange reaction. Apparatuses for integrating the metallization operations under vacuum and optionally within the same process chamber are also provided.

[0006] Accordingly, in a first aspect, the present disclosure encompasses an integrated method for selective molybdenum or tungsten deposition. In some embodiments, the method includes providing a semiconductor substrate having a via, via sidewalls composed of dielectric material, a conductive metal layer below the via, a metal overlayer on the conductive metal layer, a metal oxide or metal nitride etch stop layer on the metal overlayer, and field regions covered with a metal-containing hardmask in a processing chamber; performing a selective dry etch to remove the metal oxide or metal nitride etch stop layer without corroding the conductive metal layer, the via sidewalls, the metal-containing hardmask, or the metal overlayer; and exposing the metalcontaining hardmask to a remote plasma pre-cleaning operation and a reagent to form a protective coating over the metal-containing hardmask. The method may further include selectively depositing molybdenum or tungsten in the via over the conductive metal layer by exposure to a via metallization precursor and a hydrogen gas source; and where the protective coating prevents deposition of molybdenum or tungsten onto the metal-containing hardmask.

[0007] In some embodiments, performing a selective dry etch to remove the metal oxide or metal nitride etch stop layer includes volatilizing the metal oxide or metal nitride etch stop layer by a thermal atomic layer etch.

[0008] In some embodiments, the thermal atomic layer etch includes reacting the metal oxide or metal nitride etch stop layer with a halogen-containing reactant to form a halogenated etch stop layer and exposure of the halogenated etch stop layer to an organometal reactant to produce a volatile organohalide.

[0009] In some embodiments, the halogen-containing reactant is HF, MoFe, WFe, XeF2, F2, Ch, AlMe₂Cl, M0CI5, WC1₅, WC1₆, SiCl₄, TiCh, HC1, or BCh.

[0010] In some embodiments, the organometal reactant is Al(CHs)3, A1(CH3)2C1, Si(CH3)3Br, Si(CH3)3l, or Sn(acetylacetonate)2.

[0011] In some embodiments, the metal oxide or metal nitride etch stop layer is aluminum nitride or aluminum oxide.

[0012] In some embodiments, the remote plasma pre-cleaning operation includes at least one of nitridation, carbidization, silicidation, phosphorulation, fluorination, chlorination, bromination, iodination, reduction, or oxidation.

[0013] In some embodiments, the reagent includes a self-assembled monolayer precursor, an alkyl halide, an aromatic compound, a beta diketone, an alkylsilane, or a silicon-containing precursor.

[0014] In some embodiments, the reagent is a silicon-containing precursor; and the silicon- containing precursor is SiF4.

[0015] In some embodiments, the reagent is a self-assembled monolayer precursor; and the selfassembled monolayer precursor comprises a head group having a greater reactivity with a metalcontaining hardmask surface relative to a metal overlayer surface, a chain portion and a terminal group.

[0016] In some embodiments, the self-assembled monolayer precursor has a carbon-containing head group or a silicon-containing head group.

[0017] In some embodiments, the self-assembled monolayer precursor is a silicon-containing head group, and the self-assembled monolayer precursor is n-propyltrimethoxysilane, n- octyltrimethoxysilane, bis(dimethylamino)dimethylsilane, N- octyldimethyl(dimethylamino)silane, N-methyl-aza-2,2,4-trimethylsilacyclopentane, (3- aminopropyl)triethoxysilane, (3-aminopropyl)trimethoxysilane, N,N-dimethylaminopropyl-aza- 2-methyl-2-methoxy silacyclopentane, 2,24-trimethyl-l-thia-2-silacyclopentane, or trimethoxy(octadecyl)silane.

[0018] In some embodiments, the self-assembled monolayer precursor includes a carbon- containing head group, and the self-assembled monolayer precursor is a structure of the formula R¹-C(O)-R² or R^NCS, where R¹ comprises an organic moiety and where R² is hydrogen or an organic moiety.

[0019] In some embodiments, exposing the metal-containing hardmask to a remote plasma precleaning operation and a reagent includes simultaneous exposure of the metal-containing hardmask to the remote plasma pre-cleaning operation and the reagent, or sequential exposure of the metal-containing hardmask to the remote plasma pre-cleaning operation and the reagent.

[0020] In some embodiments, the metal -containing hardmask is tungsten, titanium, molybdenum, tantalum, or a combination thereof.

[0021] In some embodiments, the metal -containing hardmask is tungsten carbide, tungsten nitride, tungsten oxide, titanium nitride, molybdenum carbide, molybdenum nitride, tantalum nitride, or tantalum carbide.

[0022] In some embodiments, the method also includes a silicon oxide underlayer below the metal-containing hardmask.

[0023] In some embodiments, the method also includes removing the protective coating from the metal-containing hardmask.

[0024] In some embodiments, the method also includes capping the metal overlayer with a metal cap or metal-containing cap without capping the metal-containing hardmask.

[0025] In some embodiments, the metal cap is cobalt, ruthenium, molybdenum, or tungsten.

[0026] In some embodiments, the metal-containing cap is molybdenum, and where a selfassembled molecule layer is deposited over the metal overlayer before capping the metal overlayer with the metal-containing cap.

[0027] In some embodiments, the metal-containing cap is molybdenum nitride, molybdenum carbide, or molybdenum phosphide.

[0028] In some embodiments, capping the metal overlayer with a metal cap or metal-containing cap is performed before or after exposing the metal-containing hardmask to a remote plasma precleaning operation and a reagent.

[0029] In some embodiments, the conductive metal layer is copper, cobalt, ruthenium, molybdenum, tungsten, tantalum nitride, titanium nitride, molybdenum nitride, tungsten nitride, molybdenum carbide, tungsten carbide, molybdenum carbonitride, tungsten carbonitride, or a combination thereof.

[0030] In some embodiments, the metal overlayer is copper, cobalt, ruthenium, molybdenum, tungsten, tantalum nitride, titanium nitride, molybdenum nitride, tungsten nitride, molybdenum carbide, tungsten carbide, molybdenum carbonitride, tungsten carbonitride, or a combination thereof.

[0031] In some embodiments, the via metallization precursor is a molybdenum-containing precursor.

[0032] In some embodiments, the molybdenum-containing precursor is a molybdenum halide or a molybdenum oxyhalide.

[0033] In some embodiments, the molybdenum oxyhalide is MoqOnYm, where Y is a halogen; n is 1 or 2; q is 1, 2 or 4; and m is 1, 2 or 11.

[0034] In some embodiments, the molybdenum oxyhalide is MoOF4, MO4O11I, MOO2I, MoOBr4, MoChBrc, MOO2CI2, MoOCh, M02CI10 or combinations thereof.

[0035] In some embodiments, the molybdenum halide is M0CI5 or MoFe.

[0036] In some embodiments, the molybdenum-containing precursor is Mo(CO)e or C16H20M0. [0037] In a second aspect, the present disclosure encompasses an integrated method for selective molybdenum or tungsten deposition. In some embodiments, the method includes providing a semiconductor substrate comprising a via, via sidewalls composed of dielectric material, a conductive metal layer below the via, a metal overlayer on the conductive metal layer, a metal oxide or metal nitride etch stop layer on the metal overlayer, and field regions covered with a metal-containing hardmask in a processing chamber; exposing the metal-containing hardmask to a remote plasma pre-cleaning operation and a reagent to form a protective coating over the metalcontaining hardmask; and performing a selective dry etch to remove the metal oxide or metal nitride etch stop layer without corroding the conductive metal layer, the via sidewalls, the metalcontaining hardmask, or the metal overlayer. The method may further include selectively depositing molybdenum or tungsten in the via over the conductive metal layer by exposure to a via metallization precursor and a hydrogen gas source; and where the protective coating prevents deposition of molybdenum or tungsten onto the metal-containing hardmask.

[0001] In some embodiments, performing a selective dry etch to remove the metal oxide or metal nitride etch stop layer includes volatilizing the metal oxide or metal nitride etch stop layer by a thermal atomic layer etch.

[0002] In some embodiments, the thermal atomic layer etch includes reacting the metal oxide or metal nitride etch stop layer with a halogen-containing reactant to form a halogenated etch stop layer and exposure of the halogenated etch stop layer to an organometal reactant to produce a volatile organohalide.

[0003] In some embodiments, the halogen-containing reactant is HF, MoFe, WFe, XeF2, F2, Ch, AlMe₂Cl, M0CI5, WC1₅, WC1₆, SiCl₄, TiCh, HC1, or BCh.

[0004] In some embodiments, the organometal reactant is Al(CHs)3, A1(CH3)2C1, Si(CH3)3Br, Si(CH3)3l, or Sn(acetylacetonate)2.

[0005] In some embodiments, the metal oxide or metal nitride etch stop layer is aluminum nitride or aluminum oxide.

[0006] In some embodiments, the remote plasma pre-cleaning operation includes at least one of nitridation, carbidization, silicidation, phosphorulation, fluorination, chlorination, bromination, iodination, reduction, or oxidation.

[0007] In some embodiments, the reagent includes a self-assembled monolayer precursor, an alkyl halide, an aromatic compound, a beta diketone, an alkylsilane, or a silicon-containing precursor.

[0008] In some embodiments, the reagent is a silicon-containing precursor; and the silicon- containing precursor is SiF4. [0009] In some embodiments, the reagent is a self-assembled monolayer precursor; and the selfassembled monolayer precursor comprises a head group having a greater reactivity with a metalcontaining hardmask surface relative to a metal overlayer surface, a chain portion and a terminal group.

[0010] In some embodiments, the self-assembled monolayer precursor has a carbon-containing head group or a silicon-containing head group.

[0011] In some embodiments, the self-assembled monolayer precursor is a silicon-containing head group, and the self-assembled monolayer precursor is n-propyltrimethoxysilane, n- octyltrimethoxysilane, bis(dimethylamino)dimethylsilane, N- octyldimethyl(dimethylamino)silane, N-methyl-aza-2,2,4-trimethylsilacyclopentane, (3- aminopropyl)triethoxysilane, (3-aminopropyl)trimethoxysilane, N,N-dimethylaminopropyl-aza- 2-methyl-2-methoxy silacyclopentane, 2,24-trimethyl-l-thia-2-silacyclopentane, or trimethoxy(octadecyl)silane.

[0012] In some embodiments, the self-assembled monolayer precursor includes a carbon- containing head group, and the self-assembled monolayer precursor is a structure of the formula R¹-C(O)-R² or R^NCS, where R¹ comprises an organic moiety and where R² is hydrogen or an organic moiety.

[0013] In some embodiments, exposing the metal-containing hardmask to a remote plasma precleaning operation and a reagent includes simultaneous exposure of the metal-containing hardmask to the remote plasma pre-cleaning operation and the reagent, or sequential exposure of the metal-containing hardmask to the remote plasma pre-cleaning operation and the reagent.

[0014] In some embodiments, the metal -containing hardmask is tungsten, titanium, molybdenum, tantalum, or a combination thereof.

[0015] In some embodiments, the metal -containing hardmask is tungsten carbide, tungsten nitride, tungsten oxide, titanium nitride, molybdenum carbide, molybdenum nitride, tantalum nitride, or tantalum carbide.

[0016] In some embodiments, the method also includes a silicon oxide underlayer below the metal-containing hardmask.

[0017] In some embodiments, the method also includes removing the protective coating from the metal-containing hardmask.

[0018] In some embodiments, the method also includes capping the metal overlayer with a metal cap or metal-containing cap without capping the metal-containing hardmask.

[0019] In some embodiments, the metal cap is cobalt, ruthenium, molybdenum, or tungsten.

[0020] In some embodiments, the metal-containing cap is molybdenum, and where a self- assembled molecule layer is deposited over the metal overlayer before capping the metal overlayer with the metal-containing cap.

[0021] In some embodiments, the metal-containing cap is molybdenum nitride, molybdenum carbide, or molybdenum phosphide.

[0022] In some embodiments, capping the metal overlayer with a metal cap or metal-containing cap is performed before or after exposing the metal-containing hardmask to a remote plasma precleaning operation and a reagent.

[0023] In some embodiments, the conductive metal layer is copper, cobalt, ruthenium, molybdenum, tungsten, tantalum nitride, titanium nitride, molybdenum nitride, tungsten nitride, molybdenum carbide, tungsten carbide, molybdenum carbonitride, tungsten carbonitride, or a combination thereof.

[0024] In some embodiments, the metal overlayer is copper, cobalt, ruthenium, molybdenum, tungsten, tantalum nitride, titanium nitride, molybdenum nitride, tungsten nitride, molybdenum carbide, tungsten carbide, molybdenum carbonitride, tungsten carbonitride, or a combination thereof.

[0025] In some embodiments, the via metallization precursor is a molybdenum-containing precursor.

[0026] In some embodiments, the molybdenum-containing precursor is a molybdenum halide or a molybdenum oxyhalide.

[0027] In some embodiments, the molybdenum oxyhalide is MoqOnYm, where Y is a halogen; n is 1 or 2; q is 1, 2 or 4; and m is 1, 2 or 11.

[0028] In some embodiments, the molybdenum oxyhalide is MoOF4, MO4O11I, MOO2I, MoOBr4, MoChBrc, MOO2CI2, MoOCh, M02CI10 or combinations thereof.

[0029] In some embodiments, the molybdenum halide is M0CI5 or MoFe.

[0030] In some embodiments, the molybdenum-containing precursor is Mo(CO)e or C16H20M0. [0031] In a third aspect, the present disclosure encompasses an apparatus for selective molybdenum or tungsten deposition. In some embodiments, the apparatus includes a processing chamber; a substrate holder in the processing chamber; one or more gas inlets for flowing gases into the processing chamber; a vacuum source for removing gases from the processing chamber; a plasma generator for generating a plasma within the processing chamber; an etching module configured to perform a selective dry etch; an inhibition module comprising a remote plasma source and configured to form a protective coating; a metal deposition module configured to deposit molybdenum or tungsten; and one or more controllers comprising machine-readable instructions for operating the one or more gas inlets, vacuum source, and plasma generator to deposit molybdenum or tungsten onto a semiconductor substrate, the machine-readable instructions of the one or more controllers comprising instructions for: causing performance of a selective dry etch to remove a metal oxide or metal nitride etch stop layer without corroding a conductive metal layer or a metal overlayer; causing exposure of a metal -containing hardmask to a remote plasma pre-cleaning operation and a reagent to form a protective coating over the metalcontaining hardmask; and causing selective deposition of molybdenum or tungsten in a via over the conductive metal layer by exposure to a via metallization precursor; and where the protective coating prevents deposition of molybdenum or tungsten onto the metal -containing hardmask; and where the apparatus is configured to transfer a substrate between each of the etching module, the inhibition module, and the metal deposition module under vacuum.

[0032] In some embodiments, the etching module, the inhibition module, and the metal deposition module are integrated into the same process chamber.

[0033] In some embodiments, the apparatus also includes a capping module configured to cap the metal overlayer with a metal cap or metal-containing cap.

[0034] In some embodiments, the etching module, the inhibition module, the capping module, and the metal deposition module are integrated into the same process chamber.

[0035] These and other aspects are described further below with reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] FIG. 1A is a cross-sectional view of an interconnect structure to be metallized in accordance with certain disclosed embodiments.

[0037] FIG. IB is a cross-sectional view of an interconnect structure metallized by an integrated metallization method in accordance with certain disclosed embodiments.

[0038] FIG. 2 is a process flow diagram depicting an integrated metallization method in accordance with certain disclosed embodiments.

[0039] FIG. 3A provides examples of general structures for molybdenum precursors in accordance with certain disclosed embodiments.

[0040] FIG. 3B provides examples of low valent molybdenum precursors of the formula Mo(L)e in accordance with certain disclosed embodiments.

[0041] FIG. 4 provides examples of low valent dimolybdenum precursors in accordance with certain disclosed embodiments.

[0042] FIG. 5 is a process flow diagram depicting another integrated metallization method in accordance with certain disclosed embodiments.

[0043] FIG. 6 is a schematic presentation of an apparatus that is suitable for depositing metalcontaining films in accordance with certain disclosed embodiments. [0044] FIG. 7 shows a schematic view of a multi-station processing system in accordance with certain disclosed embodiments.

[0045] FIG. 8 is a schematic diagram of an example process tool for performing certain disclosed embodiments.

[0046] FIG. 9 is a schematic diagram of an example process tool for performing certain disclosed embodiments.

DETAILED DESCRIPTION

[0047] In the following description, numerous specific details are set forth to provide a thorough understanding of the presented embodiments. The disclosed embodiments may be practiced without some or all of these specific details. In other instances, well-known process operations have not been described in detail to not unnecessarily obscure the disclosed embodiments. While the disclosed embodiments will be described in conjunction with the specific embodiments, it will be understood that it is not intended to limit the disclosed embodiments.

Definitions

[0048] By “aliphatic” is meant a hydrocarbon moiety having at least one carbon atom to 50 carbon atoms (C1-50), such as one to 25 carbon atoms (C1-25), or one to ten carbon atoms (Ci- 10), and which includes saturated groups such as alkanes (or alkyl) and unsaturated groups such as alkenes (or alkenyl), alkynes (or alkynyl), and also includes cyclic versions thereof, and further including straight- and branched-chain arrangements, and all stereo and position isomers as well. Such a hydrocarbon can be unsubstituted or substituted with one or more groups, such as halogens or groups described herein for an alkyl group.

[0049] By “alkenyl” is meant an optionally substituted C2-24 alkyl group having one or more double bonds. The alkenyl group can be cyclic (e.g., C3-24 cycloalkenyl) or acyclic. The alkenyl group can also be substituted or unsubstituted. For example, the alkenyl group can be substituted with one or more substitution groups, as described herein for alkyl. Non-limiting unsubstituted alkenyl groups include C2-8 alkenyl, C2-6 alkenyl, C2-5 alkenyl, C2-4 alkenyl, or C2-3 alkenyl. Exemplary, non-limiting alkenyl groups include vinyl or ethenyl (-CH=CH2), 1 -propenyl (-CH=CHCH₃), allyl or 2-propenyl (-CH₂-CH=CH₂), 1-butenyl (-CH=CHCH₂CH₃), 2-butenyl (-CH₂CH=CHCH₃), 3-butenyl (e g. -CH₂CH₂CH=CH2), 2-butenylidene (e.g, =CH-CH=CHCH₃), and the like.

[0050] By “alkenylene” is meant a multivalent (e.g., bivalent) form of an alkenyl group, which is an optionally substituted C2-24 alkyl group having one or more double bonds. The alkenylene group can be cyclic (e.g, C3-24 cycloalkenyl) or acyclic. The alkenylene group can be substituted or unsubstituted. For example, the alkenylene group can be substituted with one or more substitution groups, as described herein for alkyl. Exemplary, non-limiting alkenylene groups include -CH=CH- or -CH=CHCH₂-.

[0051] By “alkoxy” is meant -OR, where R is an optionally substituted alkyl group, as described herein. Exemplary alkoxy groups include methoxy, ethoxy, butoxy, trihaloalkoxy, such as trifluoromethoxy, etc. The alkoxy group can be substituted or unsubstituted. For example, the alkoxy group can be substituted with one or more substitution groups, as described herein for alkyl. Exemplary unsubstituted alkoxy groups include C1-3, C1-6, C1-12, Ci-16, Ci-is, C1-20, or C1-24 alkoxy groups.

[0052] By “alkyl” and the prefix “alk” is meant a branched or unbranched saturated hydrocarbon group of 1 to 24 carbon atoms, such as methyl (Me), ethyl (Et), n-propyl (n-Pr or nPr), isopropyl (i-Pr or iPr), cyclopropyl, n-butyl (n-Bu or nBu), isobutyl (i-Bu or iBu), s-butyl (s-Bu or sBu), t- butyl (t-Bu or tBu), cyclobutyl, n-pentyl, isopentyl, s-pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, eicosyl, tetracosyl, and the like. The alkyl group can be cyclic (e.g., C3-24 cycloalkyl) or acyclic. The alkyl group can be branched or unbranched. The alkyl group can also be substituted or unsubstituted. For example, the alkyl group can include haloalkyl, in which the alkyl group is substituted by one or more halo groups, as described herein. In another example, the alkyl group can be substituted with one, two, three or, in the case of alkyl groups of two carbons or more, four substituents independently selected from the group consisting of: (1) C1-6 alkoxy (e.g., -O-Ak, wherein Ak is optionally substituted C1-6 alkyl); (2) amino (e.g., -NR^N1R^N2, where each of R^N1 and R^N2 is, independently, H or optionally substituted alkyl, or R^N1 and R^N2, taken together with the nitrogen atom to which each are attached, form a heterocyclyl group); (3) aryl; (4) arylalkoxy (e.g., -O-Lk-Ar, wherein Lk is a bivalent form of optionally substituted alkyl and Ar is optionally substituted aryl); (5) aryloyl (e.g., -C(O)-Ar, wherein Ar is optionally substituted aryl); (6) cyano (e.g., -CN); (7) carboxyaldehyde (e.g., -C(O)H); (8) carboxyl (e.g., -CO2H); (9) C3-8 cycloalkyl (e.g., a monovalent saturated or unsaturated non-aromatic cyclic C3-8 hydrocarbon group); (10) halo (e.g., F, Cl, Br, or I); (11) heterocyclyl (e.g., a 3-, 4-, 5-, 6- or 7-membered ring, unless otherwise specified, containing one, two, three, or four non-carbon heteroatoms, such as nitrogen, oxygen, phosphorous, sulfur, or halo); (12) heterocyclyloxy (e.g., -O-Het, wherein Het is heterocyclyl, as described herein); (13) heterocyclyloyl (e.g., -C(O)-Het, wherein Het is heterocyclyl, as described herein); (14) hydroxyl (e.g., -OH); (15) N-protected amino; (16) nitro (e.g., -NO2); (17) oxo (e.g., =0); (18) -CO2R^A, where R^A is selected from the group consisting of (a) C1-6 alkyl, (b) C4-18 aryl, and (c) (C4-18 aryl) C1-6 alkyl (e.g., -Lk-Ar, wherein Lk is a bivalent form of optionally substituted alkyl group and Ar is optionally substituted aryl); (19) -C(O)NR^BR^c, where each of R^B and R^c is, independently, selected from the group consisting of (a) hydrogen, (b) Ci-6 alkyl, (c) C4-18 aryl, and (d) (C4-18 aryl) C1-6 alkyl (e.g., -Lk-Ar, wherein Lk is a bivalent form of optionally substituted alkyl group and Ar is optionally substituted aryl); and (20) -NR^GR^H, where each of R^G and R^H is, independently, selected from the group consisting of (a) hydrogen, (b) an N-protecting group, (c) C1-6 alkyl, (d) C2-6 alkenyl (e.g., optionally substituted alkyl having one or more double bonds), (e) C2-6 alkynyl (e.g., optionally substituted alkyl having one or more triple bonds), (f) C4-18 aryl, (g) (C4-18 aryl) C1-6 alkyl (e.g., Lk-Ar, wherein Lk is a bivalent form of optionally substituted alkyl group and Ar is optionally substituted aryl), (h) C3-8 cycloalkyl, and (i) (C3-8 cycloalkyl) C1-6 alkyl (e.g., -Lk-Cy, wherein Lk is a bivalent form of optionally substituted alkyl group and Cy is optionally substituted cycloalkyl, as described herein), wherein in one embodiment no two groups are bound to the nitrogen atom through a carbonyl group. The alkyl group can be a primary, secondary, or tertiary alkyl group substituted with one or more substituents (e.g., one or more halo or alkoxy). In some embodiments, the unsubstituted alkyl group is a C1-2, C1-3, C1-6, C1-12, Ci-16, Ci-18, C1-20, C1-24, C2- 3, C2-6, C2-12, C2-16, C2-18, C2-20, or C2-24 alkyl group.

[0053] By “alkylene” is meant a multivalent (e.g., bivalent) form of an alkyl group, as described herein. Exemplary alkylene groups include methylene, ethylene, propylene, butylene, etc. In some embodiments, the alkylene group is a C1-3, C1-6, C1-12, Ci-16, Ci-18, C1-20, C1-24, C2-3, C2-6, C2- 12, C2-16, C2-18, C2-20, or C2-24 alkylene group. The alkylene group can be branched or unbranched. The alkylene group can also be substituted or unsubstituted. For example, the alkylene group can be substituted with one or more substitution groups, as described herein for alkyl.

[0054] By “alkylcarbonyl” is meant an alkyl group as previously defined appended to the parent molecular moiety through a carbonyl group. Exemplary, non-limiting alkylcarbonyl groups include methylcarbonyl, ethyl carbonyl, and isopropylcarbonyl among others.

[0055] The term “alkylsilyl”, as used herein, refers to SiRa group, wherein at least one R is an alkyl, and each R is independently selected from H and an alkyl. Alkylsilyls include mono, bis, and tris alkylsilyls. Examples of alkylsilyls include trimethylsilyl, dimethylsilyl, methylsilyl, triethylsilyl, diethylsilyl, and ethylsilyl.

[0056] By “alkynyl” is meant an optionally substituted C2-24 alkyl group having one or more triple bonds. The alkynyl group can be cyclic or acyclic and is exemplified by ethynyl, 1-propynyl, and the like. The alkynyl group can also be substituted or unsubstituted. For example, the alkynyl group can be substituted with one or more substitution groups, as described herein for alkyl. Nonlimiting unsubstituted alkynyl groups include C2-8 alkynyl, C2-6 alkynyl, C2-5 alkynyl, C2-4 alkynyl, or C2-3 alkynyl. Exemplary, non-limiting alkynyl groups include ethynyl (-C=CH), 1-propynyl (- OCCH3), 2-propynyl or propargyl (-CH2OCH), 1-butynyl (-OCCH2CH3), 2-butynyl (-CH₂C=CCH₃), 3-butynyl (-CH2CH2OCH), and the like.

[0057] By “alkynylene” is meant a multivalent (e.g., bivalent) form of an alkynyl group, which is an optionally substituted C2-24 alkyl group having one or more triple bonds. The alkynylene group can be cyclic or acyclic. The alkynylene group can be substituted or unsubstituted. For example, the alkynylene group can be substituted with one or more substitution groups, as described herein for alkyl. Exemplary, non-limiting alkynylene groups include -C=C- or -OCCH2-.

[0058] By “amido” is meant -N(R^N1)C(O)-, where R^N1 is H, optionally substituted alkyl, or optionally substituted aryl.

[0059] By “amino” is meant -NR^N1R^N2, where each of R^N1 and R^N2 is, independently, H, optionally substituted alkyl, or optionally substituted aryl, or R^N1 and R^N2, taken together with the nitrogen atom to which each are attached, form a heterocyclyl group, as defined herein.

[0060] By “aminoalkyl” is meant an alkyl group, as defined herein, substituted by an amino group, as defined herein.

[0061] By “aminoaryl” is meant an aryl group, as defined herein, substituted by an amino group, as defined herein.

[0062] By “aryl” is meant a group that contains any carbon-based aromatic group including, but not limited to, phenyl, benzyl, anthracenyl, anthryl, benzocyclobutenyl, benzocyclooctenyl, biphenylyl, chrysenyl, dihydroindenyl, fluoranthenyl, indacenyl, indenyl, naphthyl, phenanthryl, phenoxybenzyl, picenyl, pyrenyl, terphenyl, and the like, including fused benzo-C4-8 cycloalkyl radicals (e.g., as defined herein) such as, for instance, indanyl, tetrahydronaphthyl, fluorenyl, and the like. The term aryl also includes heteroaryl, which is defined as a group that contains an aromatic group that has at least one heteroatom incorporated within the ring of the aromatic group. Examples of heteroatoms include, but are not limited to, nitrogen, oxygen, sulfur, and phosphorus. Likewise, the term non-heteroaryl, which is also included in the term aryl, defines a group that contains an aromatic group that does not contain a heteroatom. The aryl group can be substituted or unsubstituted. The aryl group can be substituted with one, two, three, four, or five substituents, such as any described herein for alkyl.

[0063] By “ azido” is meant -N3.

[0064] By “branched alkenyl” is meant an isomer of a straight chain alkenyl compound; one having alkyl groups bonded to the main carbon chain.

[0065] By “ cyano” is meant -CN.

[0066] By “carbonyl” is meant a -C(O)- group, which can also be represented as >C=O.

[0067] By “cycloalkyl” is meant a monovalent saturated or unsaturated non-aromatic or aromatic cyclic hydrocarbon group of from three to eight carbons, unless otherwise specified, and is exemplified by cyclopropyl, cyclobutyl, cyclopentyl, cyclopentadienyl, cyclohexyl, cycloheptyl, bicyclo[2.2.1.]heptyl, and the like. The cycloalkyl group can also be substituted or unsubstituted. For example, the cycloalkyl group can be substituted with one or more groups including those described herein for alkyl.

[0068] By “deposition” or “vapor deposition” is meant a process in which a metal layer is formed on one or more surfaces of a substrate from vaporized precursor composition(s) including one or more metal containing compounds. The metal -containing compounds are vaporized and directed to and/or contacted with one or more surfaces of a substrate (i.e., semiconductor substrate or semiconductor assembly) placed in a deposition chamber. Typically, the substrate is heated. These metal containing compounds form a non-volatile, thin, uniform metal-containing layer on the surface(s) of the substrate. One operation of the method is one cycle, and the process can be repeated for as many cycles necessary to obtain the desired metal thickness.

[0069] By “dicarbonyl” is meant any moiety or compound including two carbonyl groups, as defined herein. Non-limiting dicarbonyl moi eties include 1,2-dicarbonyl (e.g., R^cl-C(O)- C(O)R^C2, in which each of R^C1 and R^C2 is, independently, optionally substituted alkyl, halo, optionally substituted alkoxy, hydroxyl, or a leaving group); 1,3-dicarbonyl (e.g., R^cl-C(O)- C(R^laR^2a)-C(O)R^C2, in which each of R^C1 and R^C2 is, independently, optionally substituted alkyl, halo, optionally substituted alkoxy, hydroxyl, or a leaving group and in which each of R^la and R^2a is, independently, H or an optional substituent provided for alkyl, as defined herein); and 1,4- dicarbonyl (e.g., R^cl-C(O)-C(R^laR^2a)-C(R^3aR^4a)-C(O)R^C2, in which each of R^C1 and R^C2 is, independently, optionally substituted alkyl, halo, optionally substituted alkoxy, hydroxyl, or a leaving group and in which each of R^la, R^2a, R^3a, and R^4a is, independently, H or an optional substituent provided for alkyl, as defined herein).

[0070] The term “fluoroalkyl”, as used herein, refers alkyl groups containing one or more fluorine substituents. In some implementations fluoroalkyls contain exclusively fluorine substituents, such as in CF3, C2F5, C3F7. Fluoroalkyls may be linear, branched and cyclic.

[0071] By “halo” is meant F, Cl, Br, or I.

[0072] By “halo containing substituent” is meant a group that contains a halo, such as a haloaliphatic or haloalkyl group.

[0073] By “haloaliphatic” is meant an aliphatic group, as defined herein, substituted with one or more halo.

[0074] By “haloalkenyl” is meant an alkenyl group, as defined herein, substituted with one or more halo. [0075] By “haloalkynyl” is meant an alkynyl group, as defined herein, substituted with one or more halo.

[0076] By “haloalkyl” is meant an alkyl group, as defined herein, substituted with one or more halogen. Non-limiting unsubstituted haloalkyl groups include C1-2 haloalkyl, C1-3 haloalkyl, Ci-4 haloalkyl, C1-5 haloalkyl, C1-6 haloalkyl, C2-3 haloalkyl, C2-4 haloalkyl, C2-5 haloalkyl, C2-6 haloalkyl, or C3-6 haloalkyl. Other non-limiting haloalkyl groups include -CXyHs-y, wherein y is 1, 2, or 3, and wherein each X is, independently, halo (F, Cl, Br, or I); -CXzFk-zCXvFh-v, wherein z is 0, 1, or 2, wherein y is 0, 1, 2, or 3, and wherein each X is, independently, halo (F, Cl, Br, or I), in which at least one of z or y is not 0; -CFkCXvFh-v, wherein y is 1, 2, or 3, and wherein each X is, independently, halo (F, Cl, Br, or I); -CXziH2-ziCX_Z2H2-z2CX_yH3-y, wherein each of zl and z2 is, independently, 0, 1, or 2, wherein y is 0, 1, 2, or 3, and wherein each X is, independently, halo (F, Cl, Br, or I), in which at least one of zl, z2, or y is not 0; and -CXzHi-z[CX_yiH3-yi][CX_y2H3- _y2], wherein z is 0 or 1, wherein each of yl and y2 is, independently, 0, 1, 2, or 3, and wherein each X is, independently, halo (F, Cl, Br, or I), in which at least one of z, yl, or y2 is not 0.

[0077] By “haloalkylene” is meant an alkylene group, as defined herein, substituted with one or more halo.

[0078] By “heterocyclyl” is meant a 3-, 4-, 5-, 6- or 7-membered ring, unless otherwise specified, containing one, two, three, or four non-carbon heteroatoms (e.g., independently selected from the group consisting of nitrogen, oxygen, phosphorous, sulfur, selenium, or halo). The 3- membered ring has zero to one double bonds, the 4- and 5-membered ring has zero to two double bonds, and the 6- and 7-membered rings have zero to three double bonds. The term “heterocyclyl” also includes bicyclic, tricyclic and tetracyclic groups in which any of the above heterocyclic rings is fused to one, two, or three rings independently selected from the group consisting of an aryl ring, a cyclohexane ring, a cyclohexene ring, a cyclopentane ring, a cyclopentene ring, and another monocyclic heterocyclic ring, such as indolyl, quinolyl, isoquinolyl, tetrahydroquinolyl, benzofuryl, benzothienyl and the like. Heterocyclics include acridinyl, adenyl, alloxazinyl, azaadamantanyl, azabenzimidazolyl, azabicyclononyl, azacycloheptyl, azacyclooctyl, azacyclononyl, azahypoxanthinyl, azaindazolyl, azaindolyl, azecinyl, azepanyl, azepinyl, azetidinyl, azetyl, aziridinyl, azirinyl, azocanyl, azocinyl, azonanyl, benzimidazolyl, benzisothiazolyl, benzisoxazolyl, benzodiazepinyl, benzodiazocinyl, benzodihydrofuryl, benzodioxepinyl, benzodioxinyl, benzodi oxanyl, benzodioxocinyl, benzodi oxolyl benzodithiepinyl, benzodithiinyl, benzodioxocinyl, benzofuranyl, b enzophenaziny 1 benzopyranonyl, benzopyranyl, benzopyrenyl, benzopyronyl, benzoquinolinyl benzoquinolizinyl, benzothiadiazepinyl, benzothiadiazolyl, benzothiazepinyl, benzothiazocinyl, benzothiazolyl, benzothienyl, benzothiophenyl, benzothiazinonyl, benzothiazinyl, benzothiopyranyl, benzothiopyronyl, benzotriazepinyl, benzotriazinonyl, benzotriazinyl, benzotriazolyl, benzoxathiinyl, benzotrioxepinyl, benzoxadiazepinyl, benzoxathiazepinyl, benzoxathiepinyl, benzoxathiocinyl, benzoxazepinyl, benzoxazinyl, benzoxazocinyl, benzoxazolinonyl, benzoxazolinyl, benzoxazolyl, benzylsultamyl, benzylsultimyl, bipyrazinyl, bipyridinyl, carbazolyl (e.g., 4H-carbazolyl), carbolinyl (e.g., P-carbolinyl), chromanonyl, chromanyl, chromenyl, cinnolinyl, coumarinyl, cytdinyl, cytosinyl, decahydroisoquinolinyl, decahydroquinolinyl, diazabicyclooctyl, diazetyl, diaziridinethionyl, diaziridinonyl, diaziridinyl, diazirinyl, dibenzisoquinolinyl, dibenzoacridinyl, dibenzocarbazolyl, dibenzofuranyl, dibenzophenazinyl, dibenzopyranonyl, dibenzopyronyl (xanthonyl), dibenzoquinoxalinyl, dibenzothiazepinyl, dibenzothiepinyl, dibenzothiophenyl, dibenzoxepinyl, dihydroazepinyl, dihydroazetyl, dihydrofuranyl, dihydrofuryl, dihydroisoquinolinyl, dihydropyranyl, dihydropyridinyl, dihydroypyridyl, dihydroquinolinyl, dihydrothienyl, dihydroindolyl, dioxanyl, dioxazinyl, dioxindolyl, dioxiranyl, dioxenyl, dioxinyl, di oxobenzofuranyl, dioxolyl, dioxotetrahydrofuranyl, dioxothiomorpholinyl, dithianyl, dithiazolyl, dithienyl, dithiinyl, furanyl, furazanyl, furoyl, furyl, guaninyl, homopiperazinyl, homopiperidinyl, hypoxanthinyl, hydantoinyl, imidazolidinyl, imidazolinyl, imidazolyl, indazolyl (e.g., IH-indazolyl), indolenyl, indolinyl, indolizinyl, indolyl (e.g., IH-indolyl or 3H-indolyl), isatinyl, isatyl, isobenzofuranyl, isochromanyl, isochromenyl, isoindazoyl, isoindolinyl, isoindolyl, isopyrazolonyl, isopyrazolyl, isoxazolidiniyl, isoxazolyl, isoquinolinyl, isoquinolinyl, isothiazolidinyl, isothiazolyl, morpholinyl, naphthindazolyl, naphthindolyl, naphthiridinyl, naphthopyranyl, naphthothiazolyl, naphthothioxolyl, naphthotri azolyl, naphthoxindolyl, naphthyridinyl, octahydroisoquinolinyl, oxabicycloheptyl, oxauracil, oxadiazolyl, oxazinyl, oxaziridinyl, oxazolidinyl, oxazolidonyl, oxazolinyl, oxazolonyl, oxazolyl, oxepanyl, oxetanonyl, oxetanyl, oxetyl, oxtenayl, oxindolyl, oxiranyl, oxobenzoisothiazolyl, oxochromenyl, oxoisoquinolinyl, oxoquinolinyl, oxothiolanyl, phenanthridinyl, phenanthrolinyl, phenazinyl, phenothiazinyl, phenothienyl (benzothiofuranyl), phenoxathiinyl, phenoxazinyl, phthalazinyl, phthalazonyl, phthalidyl, phthalimidinyl, piperazinyl, piperidinyl, piperidonyl (e.g., 4-piperidonyl), pteridinyl, purinyl, pyranyl, pyrazinyl, pyrazolidinyl, pyrazolinyl, pyrazolopyrimidinyl, pyrazolyl, pyridazinyl, pyridinyl, pyridopyrazinyl, pyridopyrimidinyl, pyridyl, pyrimidinyl, pyrimidyl, pyronyl, pyrrolidinyl, pyrrolidonyl (e.g., 2-pyrrolidonyl), pyrrolinyl, pyrrolizidinyl, pyrrolyl (e.g., 2H-pyrrolyl), pyrylium, quinazolinyl, quinolinyl, quinolizinyl (e.g., 4H-quinolizinyl), quinoxalinyl, quinuclidinyl, selenazinyl, selenazolyl, selenophenyl, succinimidyl, sulfolanyl, tetrahydrofuranyl, tetrahydrofuryl, tetrahydroisoquinolinyl, tetrahydroisoquinolyl, tetrahydropyridinyl, tetrahydropyridyl (piperidyl), tetrahydropyranyl, tetrahydropyronyl, tetrahydroquinolinyl, tetrahydroquinolyl, tetrahydrothienyl, tetrahydrothiophenyl, tetrazinyl, tetrazolyl, thiadiazinyl (e.g., 6H-l,2,5-thiadiazinyl or 2H,6H-l,5,2-dithiazinyl), thiadiazolyl, thianthrenyl, thianyl, thianaphthenyl, thiazepinyl, thiazinyl, thiazolidinedionyl, thiazolidinyl, thiazolyl, thienyl, thiepanyl, thiepinyl, thietanyl, thietyl, thiiranyl, thiocanyl, thiochromanonyl, thiochromanyl, thiochromenyl, thiodiazinyl, thiodiazolyl, thioindoxyl, thiomorpholinyl, thiophenyl, thiopyranyl, thiopyronyl, thiotri azolyl, thiourazolyl, thioxanyl, thioxolyl, thymidinyl, thyminyl, triazinyl, triazolyl, trithianyl, urazinyl, urazolyl, uretidinyl, uretinyl, uricyl, uridinyl, xanthenyl, xanthinyl, xanthionyl, and the like, as well as modified forms thereof (e.g., including one or more oxo and/or amino) and salts thereof. The heterocyclyl group can be substituted or unsubstituted. For example, the heterocyclyl group can be substituted with one or more substitution groups, as described herein for aryl.

[0079] By “hydroxyl” is meant -OH.

[0080] By “imino” is meant -NR-, in which R can be H or optionally substituted alkyl.

[0081] By “isocyanato” is meant -NCO.

[0082] By “isocyano” is meant -N ® = C ® -, and includes nitriles of the formula RN=C-, wherein R is an aliphatic, aryl or heteroaryl group.

[0083] By “isothiocyanate” is meant -N=C=S.

[0084] By “low valent” is meant the lower oxidation states when a metal has multiple oxidation states.

[0085] By “oxo” is meant an =0 group.

[0086] By “oxy” is meant -O-.

[0087] By “silyl” is meant a -SiR^JR²R³ or -SiR'R²- group. In some embodiments, each of R¹, R², and R³ is, independently, H, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aromatic, optionally substituted heteroaromatic, or optionally substituted amino. In particular embodiments, each of R¹, R², and R³ is, independently, H, optionally substituted alkyl, optionally substituted alkoxy, optionally substituted aryl, optionally substituted aryloxy, optionally substituted alkyl-aryl, optionally substituted aryl-alkyl, or optionally substituted amino. In other embodiments, the silyl group is -Si(R)_a(OR)b(NR2)c, in which each R is, independently, H, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aromatic, or optionally substituted heteroaromatic; each of a, b, and c > 0; and a + b + c = 3. In particular embodiments, each R is, independently, H, optionally substituted alkyl, optionally substituted aryl, optionally substituted alkyl-aryl, or optionally substituted aryl-alkyl. [0088] By “silyloxy” is meant -OR, where R is an optionally substituted silyl group, as described herein. In some embodiments, the silyloxy group is -O-SiR^JR²R³, in which each of R¹, R², and R³ is, independently, H, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aromatic, optionally substituted heteroaromatic, or optionally substituted amino. In particular embodiments, each of R¹, R², and R³ is, independently, H, optionally substituted alkyl, optionally substituted alkoxy, optionally substituted aryl, optionally substituted aryloxy, optionally substituted alkyl-aryl, optionally substituted aryl-alkyl, or optionally substituted amino. In other embodiments, the silyloxy group is -O-Si(R)_a(OR)b(NR2)c, in which each R is, independently, H, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aromatic, or optionally substituted heteroaromatic; each of a, b, and c > 0; and a + b + c = 3. In particular embodiments, each R is, independently, H, optionally substituted alkyl, optionally substituted aryl, optionally substituted alkyl-aryl, or optionally substituted arylalkyl.

[0089] Use of the above terms is meant to encompass substituted and unsubstituted moieties. Substitution may be by one or more groups such as alcohols, ethers, esters, amides, sulfones, sulfides, hydroxyl, nitro, cyano, carboxy, amines, heteroatoms, lower alkyl, lower alkoxy, lower alkoxycarbonyl, alkoxyalkoxy, acyloxy, halogens, trifluoromethoxy, trifluoromethyl, alkyl, aralkyl, alkenyl, alkynyl, aryl, cyano, carboxy, carboalkoxy, carboxyalkyl, cycloalkyl, cycloalkylalkyl, heterocyclyl, alkylheterocyclyl, heterocyclylalkyl, oxo, arylsulfonyl and aralkyaminocarbonyl, or any of the substituents of the preceding paragraphs or any of those substituents either directly attached or by suitable linkers. The linkers are typically short chains of 1-3 atoms containing any combination of -C-, -C(O)-, -NH-, -S-, -S(O)-, -O-, -C(O)- or -S(O)O- . Rings may be substituted multiple times.

[0090] The term “lower” modifying “alkyl”, “alkenyl”, “alkynyl”, “alkoxy” or “alkoxycarbonyl” refers to a Ci-Ceunit for a particular functionality. For example, “lower alkyl” means Ci-Ce alkyl.

[0091] By “ substituted” is meant having one or more substituent moieties whose presence does not interfere with the desired function or reactivity. Examples of substituents alkyl, alkenyl, alkynyl, cycloalkyl (non-aromatic ring), Si(alkyl)s, Si(alkoxy)3, alkoxy, amino, alkylamino, alkenylamino, amide, amidine, guanidine, hydroxyl, thioether, alkylcarbonyl, alkylcaronyloxy, alkoxycarbonyloxy, carbonate, alkoxycarbonyl, aminocarbonyl, alkylthiocarbonyl, phosphate, phosphate ester, phosphonato, cyano, halo, acylamino, imino, sulfhydryl, alkylthio, thiocarboxylate, dithiocarb oxy late, sulfate, sulfato, sulfonate, sulfamoyl, sulfonamide, nitro, nitrile, azido, heterocyclyl, ether, ester, silicon-containing moieties, thioester or a combination thereof. The substituents may themselves be substituted. For instance, an amino substituent may itself be mono or independently disubstituted by further substituents defined above, such as alkyl, alkenyl, alkynyl, and cycloalkyl (non-aromatic ring).

[0092] By “thiocyanato” is meant -SCN.

[0093] By “thioether” is meant to include to include both unidentate and multidentate (e.g. bidentate ot tridentate) thioethers, as well as ligands that contain both thioether and thiolate (or other) moieties.

[0094] Use of the above terms is meant to encompass substituted and unsubstituted moieties. Substitution may be by one or more groups such as alcohols, ethers, esters, amides, sulfones, sulfides, hydroxyl, nitro, cyano, carboxy, amines, heteroatoms, lower alkyl, lower alkoxy, lower alkoxycarbonyl, alkoxyalkoxy, acyloxy, halogens, trifluoromethoxy, trifluoromethyl, alkyl, aralkyl, alkenyl, alkynyl, aryl, cyano, carboxy, carboalkoxy, carboxyalkyl, cycloalkyl, cycloalkylalkyl, heterocyclyl, alkylheterocyclyl, heterocyclylalkyl, oxo, arylsulfonyl and aralkyaminocarbonyl, or any of the substituents of the preceding paragraphs or any of those substituents either directly attached or by suitable linkers. The linkers are typically short chains of one to three atoms containing any combination of -C-, -C(O)-, -NH-, -S-, -S(O)-, -O-, -C(O)- or -S(O)O-. Rings may be substituted multiple times.

[0095] By “unsubstituted” is meant any open valence of an atom being occupied by hydrogen. Also, if an occupant of an open valence position on an atom is not specified, then it is hydrogen.

[0096] By “unsaturated” is meant a moiety that contains double or triple carbon-carbon bonds. [0097] By “unsaturated substituent” is meant a double or triple bond containing aliphatic chain, cyclic, aryl or heteroaryl group.

[0098] The term “independently selected”, when referring to R substituent selection in a molecule containing multiple R groups, means that the selection of R substituents at different atoms of a molecule is independent and that the selection of R substituents at one atom having multiple R substituents is also independent.

[0099] The term “atomic layer deposition” (ALD) generally represents a process in which a film is formed on a substrate in one or more individual layers by sequentially adsorbing a precursor to a substrate and then chemically transforming the adsorbed precursor to form a film layer. Examples of ALD processes comprise plasma-enhanced ALD (PEALD) and thermal ALD (TALD). PEALD and TALD respectively utilize a plasma of a reactive gas and heat to facilitate a chemical conversion of a precursor adsorbed to a substrate to a film on the substrate. The terms “growth”, “deposition”, and variants thereof also can be used to refer to film formation.

[0100] The terms “atomic layer deposition cycle” and “ALD cycle” generally represent a single cycle of adsorbing a chemical precursor on a substrate surface and then chemically transforming the adsorbed chemical precursor to form a film layer on the substrate.

[0101] The term “dielectric film” generally represents a layer of an insulating material that can be polarized by an applied electric field. Example dielectric films comprise silicon oxide (SiCh), silicon nitride (SisN4), silicon oxynitride (Si3N4(i-x)Oex), silicon carbide (SiC), silicon oxycarbide (SiCh(i-x)Cx), aluminum nitride (AIN), aluminum oxide (AI2O3), tin oxides (e.g. SnO, SnCh), gallium nitride (GaN), boron nitride (BN) and gallium arsenide (GaAs) films.

[0102] The term “doping” and variants thereof generally represent the introduction of an impurity into a material for the purpose of modifying one or more physical properties of the material. The term “dopant” generally represents a chemical species introduced into another material as an impurity in a doping process.

[0103] The term “flow control hardware” generally represents components configured to place one or more chemical sources in fluid connection with a processing chamber. Flow control hardware can comprise one or more mass flow controllers and/or valves, for example. Example chemical sources include dielectric film precursor sources, halogen-containing precursor sources, reactant gas sources, and inert gas sources.

[0104] The term “forming a gas mixture” generally represents either of or both of mixing a plurality of gases before introducing the plurality of gases into the processing chamber, or mixing a plurality of gases in the processing chamber.

[0105] The term “inert gas” generally represents a gas phase material that does not react with other chemicals in a processing chamber during substrate processing. Example inert gases include helium (He), neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe), as well as nitrogen (N2) in some processes.

[0106] “Molybdenum metal” or “metallic molybdenum” as used herein, refers to material that consists essentially of molybdenum (Mo). Other elements (e.g., C, N, or O) can be present in molybdenum metal in small quantities (e.g., with a total content of less than about 15 atomic %, or less than about 10%, where hydrogen is not included in the calculation). “High purity molybdenum metal” as used herein refers to molybdenum metal that includes less than about 5% of other elements, such as less than about 1% of other elements, where hydrogen is not included in the calculation.

[0107] Molybdenum nitride (MoNx), molybdenum carbide (MoCx), molybdenum boride (MoBx), molybdenum silicide (MoSix), molybdenum boride carbide (MoB_xC_y), and molybdenum carbonitride (MoCxNy), refer to materials that consist essentially of molybdenum and nitrogen (MoNx), molybdenum and carbon (MoCx), molybdenum and boron (MoB_x), molybdenum and silicon (MoSix), molybdenum, boron and carbon (MoB_xC_y), and molybdenum, carbon and nitrogen (MoCxNy), where x and y indicate that the stoichiometry of these compounds may vary. Other elements may be present in these compounds in small quantities, e.g., in an amount of less than about 10% atomic, where hydrogen is excluded from the calculation.

[0108] The term “plasma” generally represents a gas comprising cations, free radicals and free electrons. The term “in-situ plasma” generally represents a plasma formed at a processing station in a processing chamber. The term “remote plasma” generally represents a plasma formed at a location away from a processing station in a processing chamber.

[0109] The term “plasma generator” generally represents a combination of components that can be used to form a plasma. Example components include a radiofrequency power source, an impedance matching network, and one or more electrodes.

[0110] The term “precursor” generally represents a chemical species that adsorbs to a substrate surface in an ALD process. The precursor is reacted with a reactant to convert the adsorbed precursor to a film layer.

[OHl] The term “processing chamber” or “process chamber” generally represents an enclosure in which chemical and/or physical processes are performed on substrates. The pressure, substrate temperature and atmospheric composition within a processing chamber can be controllable to perform the chemical and/or physical processes.

[0112] The term “processing tool” may generally represent a machine comprising a processing chamber and other hardware configured to enable processing to be carried out in the processing chamber.

[0113] The term “processing station” generally represents a location in a processing chamber at which a substrate is positioned during processing.

[0114] The term “reactant” generally represents a chemical species that reacts with a precursor adsorbed to a substrate surface to form a film layer in an ALD process. A reaction between a reactant and a precursor can be facilitated by thermal energy and/or a plasma in various processes.

[0115] The term “semiconductor substrate” or “substrate” as used herein refers to a substrate at any stage of semiconductor device fabrication containing a semiconductor material anywhere within its structure. It is understood that the semiconductor material in the semiconductor substrate does not need to be exposed. Semiconductor wafers having a plurality of layers of other materials (e.g., dielectrics) covering the semiconductor material, are examples of semiconductor substrates. The following detailed description assumes the disclosed implementations are implemented on a semiconductor wafer, such as on a 200 mm, 300 mm, or 450 mm semiconductor wafer. However, the disclosed implementations are not so limited. The work piece may be of various shapes, sizes, and materials. In addition to semiconductor wafers, other work pieces that may take advantage of the disclosed implementations include various articles such as printed circuit boards and the like.

[0116] The term “through-substrate via” generally represents an electrically conductive pathway in an integrated circuit that extends through a semiconductor substrate.

[0117] As used herein, the terms “top,” “bottom,” “upper,” “lower,” “above,” and “below” are used to provide a relative relationship between structures. The use of these terms does not indicate or require that a particular structure must be located at a particular location in the apparatus.

[0118] As used herein, the phrase “at least one of A, B, and C” should be construed to mean a logical (A or B or C), using a non-exclusive logical “or”, and should not be construed to mean “at least one of A, at least one of B and at least one of C”.

[0119] As used herein, the term “about” is understood to account for minor increases and/or decreases beyond a recited value, which changes do not significantly impact the desired function of the parameter beyond the recited value(s). In some cases, “about” encompasses +/-10% of any recited value. As used herein, this term modifies any recited value, range of values, or endpoints of one or more ranges.

Introduction & Context

[0120] Integrated circuits contain a plurality of patterned metal lines separated by inter-wiring spaces. Typically, the metal patterns of vertically-spaced metallization layers are electrically interconnected by vias. Metal lines formed in trench-like openings may extend substantially parallel to the semiconductor substrate. Semiconductor substrates of this type may have eight or more metallization layers to satisfy device geometry and micro-miniaturization requirements.

[0121] A common process for forming metal lines or plugs is known as “damascene”. Generally, this process involves forming an opening in the dielectric interlayer (metal conductive layer), which separates the vertically-spaced metallization layers. The opening is formed using conventional lithographic and etching techniques. After an opening is formed, the opening is filled with copper or copper alloys to form a copper line and/or via. Excess metal material on the surface of the dielectric interlayer is then removed by chemical mechanical planarization.

[0122] Provided herein are methods and apparatuses for performing integrated multi-step process including a selective etch stop layer dry etch, selective inhibition and selective molybdenum or tungsten deposition provides highly efficient metallization of a sub- 14 nm CD via in a structure.

[0123] FIG. 1A is a cross-sectional view of an interconnect structure 100 before metallization in accordance with certain disclosed embodiments. Structure 100 is made of a low K dielectric material 102. Suitable materials 102 have a dielectric constant lower than about 3.5; and may be oxides or organic materials such as SiCN (silicon carbon nitride) and SiCO (silicon carbonyl) and may further contain nitrogen, hydrogen, oxygen and combinations thereof.

[0124] The field regions of material 102 are covered optionally by a silicon oxide underlayer 104. In certain embodiments, underlayer 104 is tetraethyl orthosilicate (TEOS). If underlayer 104 is present, one or more metal hardmask layers 106 is overlaid on underlayer 104. If underlayer 104 is absent, one or more metal-containing hardmask layers 106 directly cover the field regions of material 102. The metal-containing hardmask layer 106 may include a metal such as tungsten, titanium, molybdenum, tantalum, or a combination thereof. In some embodiments the metal hardmask layer 106 is tungsten carbide, tungsten nitride, tungsten oxide, titanium nitride, molybdenum carbide, molybdenum nitride, tantalum nitride, or tantalum carbide.

[0125] An opening or trench 108 is an open area between the metal -containing hardmask layers 106. At the bottom of the opening 108 is via 110 available for metallization. The sidewalls of via 110 are composed of low K dielectric material 102.

[0126] Below via 110 lies a conductive metal layer 112. The conductive metal layer 112 may be copper, cobalt, ruthenium, molybdenum, tungsten, tantalum nitride, titanium nitride, molybdenum nitride, tungsten nitride, molybdenum carbide, tungsten carbide, molybdenum carbonitride, tungsten carbonitride, or a combination thereof.

[0127] Metal overlayer 114 overlies conductive metal layer 112. Metal layer 114 may be copper, cobalt, ruthenium, molybdenum, tungsten, tantalum nitride, titanium nitride, molybdenum nitride, tungsten nitride, molybdenum carbide, tungsten carbide, molybdenum carbonitride, tungsten carbonitride, or a combination thereof. In certain embodiments, the metal overlayer 114 is cobalt. In other embodiments, the metal overlayer is optional.

[0128] To accurately control the formation of the damascene opening, etch stop layers are commonly used. For this reason, etch stop layer 116 covers metal overlayer 114. Etch stop layer 116 may be a metal oxide or a metal nitride, such as aluminum oxynitride, aluminum nitride or aluminum oxide.

[0129] Optionally, an oxygen-doped silicon carbide layer 118 may overlie etch stop layer 116.

[0130] FIG. IB is a cross-sectional view of an interconnect structure 150 as metallized by the disclosed integrated metallization method. FIG. IB provides an overview of the integrated methods which include selective dry etch to remove the etch stop layer, selective inhibition to protect the metal-containing hardmask and optional capping of the overlayer to effect selective metal deposition; described herein in greater detail in FIGS. 2 and 5. It is desirable to fill the area 152 of the via above the conductive metal layer by depositing a metal such as molybdenum or tungsten subsequent to etch stop removal. However, certain challenges are associated with such a metal deposition, such as unwanted metal deposition on the metal-containing hardmask, and corrosion of the metal overlayer during etch stop removal and/or metal deposition.

[0131] In order to inhibit the metal from being deposited on the metal-containing hardmask, a protective coating 154 may be applied over the metal-containing hardmask. A selective dry etch to remove the etch stop layer may be performed before or after application of protective coating 154. Moreover, the metal layer may optionally be capped with a metal or metal-containing cap 156 either before or after protective coating 154 is applied, in order to protect the underlying metal overlayer and/or the conductive metal layer beneath it from corrosion due to either etching, deposition, or both etching and deposition. The metal or metal-containing cap 156 may also be advantageously directly applied to the conductive metal layer if a metal overlayer is absent.

[0132] FIG. 2 is a process flow diagram depicting an integrated metallization method in accordance with certain disclosed embodiments. The integrated method 200 involves a selective dry etch operation 204, a metal-containing hardmask operation 206, an optional capping of the metal overlayer, and a selective deposition operation 210 for depositing molybdenum or tungsten. Each aspect will be discussed in greater detail in the following paragraphs.

[0133] In operation 202, a semiconductor substrate having the structure as described for FIG. 1A above is provided to a processing chamber. Returning to FIG. 2, in some embodiments, the semiconductor substrate includes a via, via sidewalls composed of dielectric material, a conductive metal layer below the via, a metal overlayer on the conductive metal layer, a metal oxide or metal nitride etch stop layer on the metal overlayer, and field regions covered with a metal-containing hardmask

[0134] In operation 204, a selective dry etch is performed to remove the etch stop layer without corroding the conductive metal layer, the via sidewalls, the metal-containing hardmask, or the metal overlayer. Conventional wet chemistry for etching is potentially disadvantageous as it may cause rupture of the metal overlayer which then can lead to diffusion of the underlying metal of the conductive metal layer (such as copper) into the area where metallization is desired. Etch stop layer opening by wet chemistry also may lead to problematic oxidation of metals which must then be removed by an additional operation. [0135] In certain embodiments, the selective dry etch is a thermal atomic layer etch performed under vacuum which volatilizes the metal oxide or metal nitride etch stop layer. The thermal atomic layer etch is based on gas-phase halogenation and ligand exchange in which halogenation converts a metal containing compound (etch stop layer) to a halogenated metal compound (etch stop layer). The halogenated metal compound then undergoes a ligand exchange reaction with a metal precursor, in a redistribution reaction which produces volatile organohalide species which can leave the surface, resulting in etching. In some embodiments, the thermal atomic layer etch is performed at a temperature range of from about 200 °C to about 350 °C; and at a pressure of from about 0.1 to about 50 Torr.

[0136] In some embodiments, the thermal atomic layer etch includes reacting the metal oxide or metal nitride etch stop layer with a halogen-containing reactant to form a halogenated etch stop layer and exposure of the halogenated etch stop layer to an organometal reactant to produce a volatile organohalide.

[0137] Suitable halogen-containing reactants include, but are not limited to, HF, MoFe, WFe, XeF₂, F₂, Cl₂, AlMe₂Cl, MoCh, WCh, WC1₆, SiCl₄, TiCl₄, HC1, or BC1₃. Suitable organometal reactants include, but are not limited to, Al(CHs)3, A1(CH3)₂C1, Si(CH3)3Br, Si(CH3)3l, or Sn(acety 1 acetonate)₂.

[0138] In operation 206, growth of molybdenum or tungsten on the metal-containing hardmask during deposition step 210 is inhibited by forming a protective coating over the metal -containing hardmask. The protective coating may be formed by exposing the metal-containing hardmask to a remote plasma pre-cleaning operation and a reagent in a single chamber. The remote plasma pre-cleaning operation may be at least one of nitridation, carbidization, silicidation, phosphorulation, fluorination, chlorination, bromination, iodination, reduction, or oxidation. Suitable reagents include, but are not limited to, small molecule inhibitors such as a self-assembled monolayer precursor, an alkyl halide, an aromatic compound, a beta diketone, an alkylsilane, or a silicon-containing precursor such as SiF₄. The exposure of the metal-containing hardmask to a remote plasma pre-cleaning operation and a reagent may be either by simultaneous exposure of the metal-containing hardmask to the remote plasma pre-cleaning operation and the reagent, or by sequential exposure of the metal -containing hardmask to the remote plasma pre-cleaning operation and the reagent.

[0139] The reagent may be a self-assembled monolayer precursor that has 1) a head group having a greater reactivity with a metal -containing hardmask surface relative to a metal overlayer surface (such as a carbon- or silicon- containing head group), 2) a chain portion and 3) a terminal group. Examples of self-assembled monolayer precursors with silicon-containing head groups include, but are not limited to, n-propyltrimethoxysilane, n-octyltrimethoxysilane, bis(dimethylamino)dimethylsilane, N-octyldimethyl(dimethylamino)silane, N-methyl-aza-2,2,4- trimethylsilacyclopentane, (3 -aminopropyl)tri ethoxy silane, (3-aminopropyl)trimethoxysilane, N,N-dimethylaminopropyl-aza-2-methyl-2-methoxy silacyclopentane, 2,24-trimethyl- 1 -thia-2- silacyclopentane, or trimethoxy(octadecyl)silane.

[0140] Examples of self-assembled monolayer precursors with carbon-containing head groups include, but are not limited to, structures of the formula R^J-C(O)-R² or R^NCS, where R¹ is an organic moiety and where R² is hydrogen or an organic moiety.

[0141] Suitable self-assembled monolayer precursors are further described in U.S. Patent Pub. No. 2022/0362803 published Nov. 17, 2022 and entitled “Selective Attachment to Enhance SiCUSiNx Etch Selectivity”; suitable alkyl halides are further described in PCT Publication No. WO 2023/114640 published June 22, 2023 and entitled “Deposition of Metals in Recessed Features with the Use of Halogen-Containing Deposition”; and suitable aromatic compounds, beta diketones and alkylsilanes are further described in PCT Publication No. WO 2021/046061, published March 11, 2021 and entitled “Small Molecule Films for Sacrificial Bracing, Surface Protection and Queue-Time Management”; the contents of which are all hereby incorporated by reference.

[0142] In certain embodiments, the inhibition operation 206 requires an additional anneal step. In certain embodiments the inhibition operation 206 is performed cyclically, by alternating dosage of inhibitor with an anneal step.

[0143] In operation 208, the metal overlayer is optionally also protected by forming a metal or metal-containing cap over it. The cap prevents corrosion of conductive metal layer (such as copper) and/or the metal overlayer (such as cobalt) over the conductive metal layer during the molybdenum or tungsten deposition operation 210. The cap is a material which is compatible with copper and/or molybdenum. The materials and conditions for application of the cap are selected in order to avoid deposition of the cap on any dielectric material or the metal-containing hardmask. [0144] When the cap made is of cobalt or ruthenium, deposition can be done without the assistance of an inhibitor. However, when the metal-containing cap includes molybdenum (such as a molybdenum cap, or, a self-assembled molecule layer as described above may be deposited over the metal overlayer before capping the metal overlayer with the metal-containing cap.

[0145] Moreover, for a dual damascene interconnect structure which does not have a metal overlayer on the conductive metal layer, the metal or metal-containing cap may be applied directly to the conductive metal layer to protect it.

[0146] This optional operation may be performed either subsequent to the inhibition operation 206 as shown in the flow diagram, or prior to inhibition operation 206 (not shown). Suitable metal caps include cobalt, ruthenium, molybdenum, or tungsten.

[0147] In some embodiments, when the metal-containing cap includes molybdenum, such as molybdenum nitride, molybdenum carbide, or molybdenum phosphide; a self-assembled molecule layer as described above may be deposited over the metal overlayer before capping the metal overlayer with the metal-containing cap.

[0148] In some embodiments, operation 208 is performed at a temperature range of from about 0 °C to about 350 °C; and at a pressure of from about 0.1 to about 90 Torr.

[0149] In some embodiments an optional post-anneal step under H2, N2, NH3, PH3, Sikh, CO2, CO, CH4, or a combination thereof is performed after operation 208.

[0150] In operation 210, a selective deposition of molybdenum or tungsten is performed. This operation is selective both by virtue of the inhibition operation 206, the selective dry etch 204, and the optional capping of the metal overlayer; as well as by virtue of the choice of metal precursors and deposition process conditions. Suitable precursors are described in detail below.

Molybdenum Precursors

[0151] Generally, molybdenum precursors may have from two (M0L2) to six (MoLe) ligands and can include molybdenum in a wide range of oxidation states ranging from 0 to +6. Molybdenum precursors may also be dimolybdenum compounds having 1) two molybdenum atoms singly or multiply bonded to one another; or 2) two molybdenum atoms connected by a linking group such as a bidentate ligand.

[0152] Suitable molybdenum containing precursors include molybdenum halides and oxyhalides, such as fluorides, chlorides, bromides, oxyfluorides, oxychlorides, and oxybromides where molybdenum may be in any of the oxidation states from +2 to +6.

[0153] Molybdenum chloride precursors are given by the formula MoClx, where x is 2, 3, 4, 5, or 6, and include molybdenum dichloride (M0CI2), molybdenum trichloride (M0CI3), molybdenum tetrachloride (M0CI4), molybdenum pentachloride (M0CI5), and molybdenum hexachloride (MoCk). In some embodiments, M0CI5 or MoCk are used. While the description chiefly refers to MoCk precursors, in other embodiments, other molybdenum halide precursors may be used. Molybdenum halide precursors are given by the formula MoX_z, where X is a halogen (fluorine (F), chlorine (Cl), bromine (Br), or iodine (I)) and z is 2, 3, 4, 5, or 6. Examples of MoXz precursors include molybdenum fluoride (MoFe). In some embodiments, a non-fluorine- containing MoXz precursor is used to prevent fluorine etch or incorporation. In some embodiments, a non-bromine-containing and/or a non-iodine-containing MoXz precursor is used to prevent etch or bromine or iodine incorporation.

[0154] Molybdenum oxyhalide precursors are given by the formula MoOyXz, where X is a halogen (fluorine (F), chlorine (Cl), bromine (Br), or iodine (I)) and y and z are numbers greater than 0 such that MoOyXz forms a stable compound. Examples of molybdenum oxyhalides include molybdenum dichloride dioxide (MOO2CI2), molybdenum tetrachloride oxide (MoOCh), molybdenum tetrafluoride oxide (MoOF4), molybdenum dibromide dioxide (MoCLBrc), and the molybdenum iodides MOO2I, and MO4O11I.

[0155] In some embodiments discussed herein, the precursors having molecular weights of less than about 450 g/mol, such as less than about 400 g/mol.

[0156] In some embodiments the molybdenum-containing precursor has a formula MoXnYm, wherein X is a chalcogen (e.g., oxygen or sulfur), Y is a halogen (e.g., fluorine, chlorine, bromine, or iodine), n is 0, 1, or 2 and m is 2, 3, 4, 5, or 6. Examples of halogen-containing molybdenum- containing precursors include without limitation M0CI5, M02CI10, MOO2CI2, and MoOCh. Another example of a halogen-containing molybdenum-containing precursor is MoFe.

Low-Valent Molybdenum Complexes

[0157] Low valent molybdenum complexes or compounds are those having molybdenum in low oxidation states 0, +1, +2 or +3. In certain embodiments, the low valent molybdenum complexes may be efficacious precursors as it is easier to reduce Mo(I) to Mo (0) or Mo(II)/(III) to Mo(0) than it is to reduce the more commonly utilized Mo(IV)/(V) halide precursors.

[0158] Low valent molybdenum precursors may offer a less circuitous surface redox process to obtain fully reduced molybdenum metal films with minimal impurities. Without wishing to be bound by a particular theory, this is likely the result of the ease of reduction of low valent molybdenum precursors.

Molybdenum Zero Complexes

[0159] Mo (0) precursors are advantageous because do not require any reduction steps, and are energetically facile, as their use provides a lower energy barrier to Mo film formation upon exposure to a reducing agent. They are especially amenable in multi-step ALD processes where surface-ligand exchange and conversion (reduction) occurs. Molybdenum hexacarbonyl (Mo(CO)e) is an example of a molybdenum complex existing in the oxidation state of zero.

[0160] A general structure for low valent molybdenum precursors having one molybdenum is MoL_n (Formula I), and general structures for low valent molybdenum precursors with two molybdenum atoms are M02L11 (Formula II) or L_nMo(L’)mMoL_n (Formula III). For any of Formulas I-III, each L is independently a monodentate ligand, ambidentate ligand, bidentate ligand or tridentate ligand and n is an integer of 2 to 6. For Formula III, L’ is a linking moiety such as a bidentate ligand; and m is an integer of 1 to 3.

Monodentate Ligands

[0161] Suitable ligands for the low valent molybdenum complexes include monodentate ligands, also referred to as unidentate ligands. A monodentate ligand is one which binds or coordinates to a metal center via one coordination site of the metal only, or via one site of the ligand only. They may include a wide variety of substituents such as hydrogen, halo, hydroxy, alkyl silyl, silylalkyl, alkenyl, alkynyl, allyl, alkoxy, alkenoxy, alkynoxy, thioalkoxy, aliphatic acyl, -CF3, nitro, amino, imino, -N(CI-C3 alkyl)C(O)(Ci-C3 alkyl), -C1-C3 alkylamino, alkenylamino, alkynylamino, di(Ci- C3 alkyl)amino, -C(O)O-(Ci-C₃ alkyl), -C(O)NH-(CI-C₃ alkyl), -CH=NOH, -P(Ci-C₃ alkyl)₃, - PO3H2, -OPO3H2, -C(O)N(CI-C3 alkyl)2, haloalkyl, alkoxycarbonyl, alkoxyalkoxy, carboxaldehyde, carboxamide, cycloalkyl, cycloalkenyl, cycloalkynyl, aryl, aroyl, aryloxy, arylamino, biaryl, thioaryl, heterocyclyl, alkylheterocyclyl, heterocyclylalkyl, heterocycloyl, alkylaryl, alkylcarbonyl, CO, =0, =S, =N, =CR, =CR2, -NO, aralkenyl, aralkyl, sulfonyl, sulfonamido, sulfonimido, carbamate, aryloxyalkyl, carboxyl, carboxy, -C(O)NH(benzyl), amido, azido, isocyanato, thiocyanato, isothiocyanato, cyano, isocyano or cyclyl groups where each R is independently an aliphatic such as haloalkyl or aryl such as a haloaryl group.

[0162] In some embodiments, the low valent molybdenum precursors include at least one OR, P(R)₃, CNR, allyl or aryl group, where each R is independently an aliphatic, aryl, haloalkyl or haloaryl group.

[0163] In some embodiments, the monodentate ligand can include an oxygen atom. In particular embodiments, one or more ligands can be optionally substituted alkoxy. Non-limiting ligands include, e.g., methoxy, ethoxy, isopropoxy (i-PrO) and t-butoxy (t-BuO). Non-limiting molybdenum-containing precursors include, e.g., Mo(CH2F)(t-BuO)3, Mo(CF3)(t-BuO)3, Mo(CH₂I)(t-BuO)₃, Mo(CI₃)(t-BuO)₃, Mo(CH₂CH₂F)(t-BuO)3, Mo(CH₂CH₂I)(t-BuO)3, Mo(CH₂F)₂(t-BuO)2, Mo(CF₃)₂(t-BuO)2, Mo(CH₂I)₂(t-BuO)2, Mo(CI₃)₂(t-BuO)2, Mo(CH₂CH₂F)2(t-BuO)2, Mo(CH₂CH₂I)2(t-BuO)2, Mo(t-BuO)₂, Mo(CH₃)(t-BuO)₃, Mo(CH₂CH₃)(t-BuO)3, Mo(CH=CH₂)(t-BuO)₃, Mo(CH=CHCH₃)(t-BuO)₃, Mo(CH₂-CH=CH₂)(t- BUO)₃, Mo(C=CH)(t-BuO)₃, Mo(C=CCH₃)(t-BuO)₃, Mo(CH₂C=CH)(t-BuO)₃, or Mo(acac)₂.

[0164] In certain embodiments, the oxygen-containing monodentate ligand may be -OC(CH3)(CF₃)2, -OC(CH₃)2(CF₃), -OC(CH₃)3, -OSilC (such as -OSiPh₃), C=O (carbonyl ligand) or -OAr (where Ar groups include but are not limited to phenyl, mesitylenyl, 2,6-iPr2CeH3, hexa-z o-propyl-ter-phenyl, and 2,3,5,6-Ph4CeH). In certain embodiments, the oxygen-containing ligand is an ether, epoxide, or ketone. In some cases, the oxygen-containing ligand may be a silyl oxy group.

[0165] In certain embodiments, the ligand is a phosphorous-containing ligand. Suitable complexes may be of the formula R3P where R is a halo, aliphatic or aryl group. Examples include secondary or tertiary organophosphines such as P(t-Bu)s, PMes, PPhs, P(OMe)3, P(OEt)3, PCI3 or PF3. In some embodiments, the phosphorus containing ligand is phosphanetriyltris(benzene sulfonic acid). Other phosphorus containing ligands include -CH2P(CH3)3, -P(O)OH, - P(O)(OCH₃)₂, -P(O)(OCH₂CH₃)2, and -CH(Si(CH3)3)(P(CH₃)3).

[0166] In some embodiments, the ligand is an isocyano functional group, including isonitriles of the formula -C=NR, such as isocyanoalkyl, isocyanohaloalkyl, isocyanoaryl, isocyanohaloaryl. In some embodiments, R is an aliphatic group such as a haloalkyl, or an aryl group such as haloaryl. In certain embodiments, R may be -CH2CF3, -C(F)=CF2, -C(F)=C(F)CF3, - CF2C(F)=CF2, -CH(CF₃)₂, -CH(CH3)(CF3), or -C(CH3)2(CF3). In certain embodiments, R is a perfluoroalkyl substituent of one to ten carbon atoms such as perfluorinated methyl, ethyl, i- propyl, n-propyl, t-butyl, sec-butyl, n-butyl, cyclopentyl, n-pentyl, cyclohexyl or n-hexyl group.

[0167] In some embodiments, the monodentate ligand is one with sp² hybridized character such as an allyl, allenyl, ethenyl, indenyl or cyclopentadienyl group. Two of the same such substituents or two different such substituents may be utilized to form precursors with a sandwich structure. In some embodiments, one such substituent is utilized to form a half-sandwich complex. In certain embodiments, the ligand may be mesitylenyl, tolyl, xylyl, benzyl, anilinyl, N,N-dimethylanilinyl, tetrahydrofuranyl, piperidinyl, pyrrolyl, pyrrolidinyl, pyridinyl, piperidinyl, imidazolyl, or pyrimidinyl.

[0168] In some embodiments, the ligand is an atom which is connected directly to molybdenum via a multiple bond such as a double or triple bond. Examples include =0, =NR, =S, =N, =CR2 or =CR, where each R is independently an aliphatic, aryl, haloalkyl or haloaryl group.

[0169] In some embodiments, the molybdenum-containing precursor has at least one optionally substituted haloalkyl group. Non-limiting haloaliphatic group ligands include -CXyEE-y, wherein y is 1, 2, or 3, and wherein each X is, independently, halo (F, Cl, Br, or I); -CXzEk-zCXyEE-y, wherein z is 0, 1, or 2, wherein y is 0, 1, 2, or 3, and wherein each X is, independently, halo (F, Cl, Br, or I), in which at least one of z or y is not 0; or -CEECXyEE-y, wherein y is 1, 2, or 3, and wherein each X is, independently, halo (F, Cl, Br, or I). Yet other non-limiting haloalkyl groups include fluoromethyl (-CH2F), difluoromethyl (-CHF2), trifluoromethyl (-CF3), chloromethyl (- CH2CI), dichloromethyl (-CHCI2), trichloromethyl (-CCI3), bromomethyl (-CEEBr), dibromomethyl (-CHBrc), tribromomethyl (-CBn), iodomethyl (-CH2I), diiodomethyl (-CHI2), triiodomethyl (-CI3), bromofluoromethyl (-CHFBr), chlorofluoromethyl (-CHFC1), fluoroiodomethyl (-CHFI), 2-fluoroethyl (-CH2CH2F), 2-chloroethyl (-CH2CH2CI), 2-bromoethyl (-CEBCEBBr), 2-iodoethyl (-CH2CH2I), 2,2-difluoroethyl (-CH2CHF2), 2,2-dichloroethyl (- CH2CHCI2), 2,2-dibromoethyl (-CEBCHBrc), 2,2-diiodoethyl (-CH2CHI2), 2,2-fluoroiodoethyl (- CH2CHFI), and the like. In particular embodiments, the C1-2 haloalkyl includes P-halo-substituted ethyl. Yet other haloaliphatic groups include Ci-4 haloalkyl, C2-4 haloalkenyl, and C2-4 haloalkynyl.

[0170] In other embodiments, the ligand is an optionally substituted alkyl group, optionally substituted alkenyl, or optionally substituted alkynyl. Non-limiting groups include -CnH2n+i, in which n is 1 or 2; -CnFbn-i, in which n is 2, 3, or 4; or -CnH2n-3, in which n is 2, 3, or 4. Yet other non-limiting groups include methyl (-CH3), ethyl (-CH2CH3), vinyl or ethenyl (-CH=CH2), 1- propenyl (-CH=CHCH ), allyl or 2-propenyl (-CH2-CH=CH2), 1-butenyl (-CH=CHCH2CH3), 2- butenyl (-CH2CH=CHCH3), 3-butenyl (e.g. -CH2CH2CH=CH2), ethynyl (-C=CH), 1-propynyl (- OCCH3), 2-propynyl or propargyl (-CH2C=CH), 1-butynyl (-OCCH2CH3), 2-butynyl (-CH2C=CCH3), 3-butynyl (-CH2CH2C=CH), 2-methyl-l -propenyl (CH=C(CH3)2, isopropenyl (C(CH₃)=CH₂, 1 -methylallyl (CH(CH₃)CH=CH₂ and the like.

[0171] In some embodiments, the monodentate ligand may be -CH₂P(CH₃)3, -CH(Si(CH₃)3)(P(CH₃)3), -C(O)C₃F₇, or -CHCHSO2C6H5.

[0172] In some embodiments, the monodentate ligand includes a sulfur atom. In particular embodiments, one or more monodentate ligands can be -SO2CF3, -SO2C3N2H3, -CHCHSO2C6H5, -SO2OCH3, or -SO2C6H4CH3.

[0173] In some embodiments, the monodentate ligand includes a nitrogen atom. In particular embodiments, one or more monodentate ligands can be optionally substituted amino or optionally substituted bis(trialkylsilyl)amino. Non-limiting ligands can include, e.g., -NMe2, -NEt2, -NMeEt, -N(t-Bu)-[CHCH₃]₂-N(t-Bu)- (tbba), -N(SiMe₃)₂, and -N(SiEt₃)₂.

[0174] In some embodiments, the optionally substituted amino is -NR¹ R², in which each R¹ and R² is, independently, H or alkyl; or in which R¹ and R², taken together with the nitrogen atom to which each are attached, form a heterocyclyl group, as defined herein. In other embodiments, the optionally substituted bis(trialkylsilyl)amino is -N(SiR¹R²R³)2, in which each R¹, R², and R³ is, independently, alkyl. In yet other embodiments, the optionally substituted trialkylsilyl is -SiR^JR²R³, in which each R¹, R², and R³ is, independently, alkyl.

[0175] In other embodiments, the low valent molybdenum precursor includes a first ligand that is -NR'R² and a second ligand that is -NR'R², in which each R¹ and R² is, independently, H or alkyl. In yet other embodiments, the formula includes a first ligand that is -OR¹ and a second ligand that is -OR¹, in which each R¹ is, independently, H or alkyl.

[0176] In some embodiments, the monodentate ligand is optionally substituted alkyl. Nonlimiting alkyl groups include, e.g., CnH2n+i, where n is 1, 2, 3, or greater, such as methyl, ethyl, n- propyl, isopropyl, n-butyl, isobutyl, s-butyl, or t-butyl. In various embodiments, the ligand has at least one beta-hydrogen or beta-halogen.

[0177] In some embodiments, at least one monodentate ligand is optionally substituted haloalkyl. Non-limiting haloalkyl groups include, e.g., CnFbn+i-zXz, wherein n is 1, 2, 3, or greater; wherein z is 1 to 2n+l (e.g., 1 to 3, 1 to 5, or 1 to 7); and wherein each X is, independently, halo (F, Cl, Br, or I).

[0178] In some embodiments, at least one monodentate ligand is optionally substituted alkenyl or optionally substituted alkynyl. Non-limiting alkenyl groups include, e.g., CnFbn-i, where n is 2, 3, 4, or greater, such as ethenyl, 1 -propenyl, 2-propenyl, 1-butenyl, 2-butenyl, or 3-butenyl. Non-limiting alkynyl groups include, e.g., CnH2n-3, where n is 2, 3, 4, or greater, such as ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, or 3-butynyl.

[0179] Alkynyl groups are also suitable monodentate ligands in certain embodiments. In some embodiments, the carbon-carbon triple bond is not bound directly to the molybdenum, for example in a formula R¹CCCH2MoL3 where R¹ is a C1-C2 linear or branched alkane such as methyl or ethyl; and L is an amino (dimethylamino, diethylamino, ethylmethylamino, methylpropylamino, aminiocyclopentane, aminocyclohexane) or alkoxy group (methoxy, ethoxy, n-propoxy, isopropoxy, t-butoxy, sec-butoxy, or n-butoxy).

[0180] Alkyne compounds which have a carbon-carbon triple bond directly bonded to the molybdenum atom will hydrolyze in the presence of water similar to, although much slower than, amino and alkoxy groups. Therefore, compounds such as (R¹C=C)3MoR² and (R¹C=C)4Mo where R¹ is a simple alkane such as methyl or ethyl, and R² is a C1-C2 hydrocarbon are precursors having monodentate ligands in accordance with certain embodiments. In compound (R¹C=C)3MoR² the molybdenum center has three alkynes with the carbon-carbon triple bond bonded to the molybdenum center. Tetra-alkynes such as those shown for (R¹C=C)4Mo.

[0181] In some embodiments, the monodentate ligand is halo. In particular, the metalcontaining precursor can be a metal halide or organometal halide. Non-limiting metal halides and organometal halides include FCH2M0X3, CF3M0X3, ICH2M0X3, CI3M0X3, CH2FCH2M0X3, CH2ICH2M0X3, M0X2, or M0X4, in which each X is, independently, halo. In other embodiments, the metal-containing precursor is RM0X3, in which R is Ci-4 haloalkyl, C2-4 haloalkenyl, or C2-4 haloalkynyl; and in which each X is, independently, halo. In yet other embodiments, the metal- containing precursor is RM0X3, in which R is C1-2 alkyl, C2-4 alkenyl, or C2-4 alkynyl; and in which each X is, independently, halo.

[0182] In other embodiments, the monodentate ligand is Ci- C3 aliphatic (wherein the C1-C3 aliphatic may be optionally substituted with a ketone, an alkoxy group, an epoxy group) or a - C(O)Ci-C3 alkyl group. Ethers, ketones or epoxide-containing ligands on the low valent molybdenum-containing precursors may be advantageous to assist in crosslinking.

[0183] In some embodiments, the monodentate ligand can include a silicon atom. In some embodiments, the monodentate ligand may be -Si(CH3)3, -Si(C2Hs)3, -CH2Si(CH3)3, - CH(Si(CH3)3)2 or -C(Si(CH3)3)3. In particular embodiments, one or more ligands can be optionally substituted trialkylsilyl or optionally substituted bis(trialkylsilyl)amino. Non-limiting ligands can include, e.g., -SiMes, -SiEt3, -N(SiMe3)2, and -N(SiEt3)2.

[0184] For any formula herein, each monodentate ligand may independently be hydrogen, halo, azido, cyano, alkylcarbonyl, isothiocyanato, thiocyanato, optionally substituted alkyl, optionally substituted aryl, optionally substituted amino, optionally substituted bis(trialkylsilyl)amino, optionally substituted trialkylsilyl, or optionally substituted alkoxy (e.g., -OR¹, in which R¹ can be alkyl).

[0185] The present disclosure also encompasses hydrogen as a monodentate ligand. An example of a complex having a hydrogen monodentate ligand is a molybdenum hydride precursor such as Mo(Cp)₂H₂, where Cp is cyclopentadienyl.

[0186] The monodentate ligand may be an ambidentate ligand, which has two potential donor atoms, but only attaches to a metal via one of the two. In certain embodiments, the ambidentate ligand is NCh', which may bond to a metal through either the nitrogen atom or the oxygen atom.

Bidentate Ligands

[0187] Suitable ligands for the low valent molybdenum complexes include bidentate ligands. A bidentate ligand (also referred to as a chelating ligand) is one which binds or coordinates to a metal center via two coordination sites of the metal, or via two sites of the ligand. Bidentate ligands are Lewis bases that donate two pairs of electrons to a metal atom. The bidentate ligands may be neutral or anionic. Furthermore, the bidentate ligands may have the same two coordination atoms, or may be unsymmetrical bidentate ligands, where the two coordination atoms are not the same. In some embodiments, the bidentate ligands may be ethylenediamine (en), bipyridyl (bpy), 1,2- bis(dimethylphosphino)ethane (dmpe), phenanthroline (phen), l,2-bis(diphenylphosphino)ethane (dppe), acetate (OAc), oxalate (ox), or acetyl acetonate (acac). Precursors with bidentate ligands include, but are not limited to, molybdenum di acetyl acetonate dioxide (MoO2(acac)2). [0188] Example structures containing the bidentate ligand include, but are not limited to

[0189] The bidentate ligand may be a linking moiety L’ of the structure -(E)_e- where each E independently includes NR, C(R)n, Si(R)n, S, O or P(R)_n; each R independently includes hydrogen, aryl, amino or aliphatic; n is 0, 1 or 2 and e is 1, 2, 3, 4 or 5.

[0190] Suitable low valent molybdenum precursors may contain one, two or three bidentate ligands each of which may be the same or different.

[0191] The bidentate ligand may be an amidinate, an amidate, an iminopyrrolidinate, a di azabutadiene, a beta-imino amide, an alpha-imino alkoxide, a beta-diketiminate, a beta- ketoiminate, a beta-diketonate, a pyrazolate, a beta-amino alkoxide, a guanidinidate, a dithiolene, an alpha-iminothiolene, an alpha-dithiolate, or a beta-dithiolate. Other examples of suitable materials include the bidentate ligands described in US 2022/0170155 and WO 2021/035236, which are incorporated herein by reference in their entireties.

Tridentate Ligands

[0192] A tridentate ligand is one with three atoms that can function as acceptors in a coordination complex. In certain embodiments, the tridentate ligand three nitrogen, three sulfur, three phosphorus or three oxygen atoms available for chelation. Tridentate ligands include cis,cis- 1,3,5-triaminocyclohexane, 1,4,7-triazacyclononane, 1,4, 7, -trimethyl- 1, 4, 7-triazacy cl ononane, 1,4,7-trithiacyclononane, bis(diphenylphosphinoethyl)phenylphosphine, N,N,N’,N”N”- pentamethyldiethylenetriamine, tris(4S-isopropyl-2-oxazolinyl)phenylborate, tris(4,4-dimethyl- 2-oxazolinyl)phenyl borate, trispyrazolylborate, 1,4,7-trioxonane, diethylenetriamine, or an iminodiacetate anion. Suitable low valent molybdenum precursors may contain one, two or more tridentate ligands which may be the same or different.

[0193] The low valent molybdenum precursors may have two to six ligands. Each occurrence of L may independently be a monodentate, ambidentate, bidentate or tridentate ligand as described above. Low valent molybdenum precursors having two ligands may be of the formula M0L2. Precursors with two ligands include, but are not limited to, bis(ethylbenzene)molybdenum (C16H20M0).

[0194] FIG. 3A illustrates example structures for molybdenum precursors having three ligands (Formula XIV), four ligands (Formula V and Formula VI) or five ligands (Formula IX and Formula X) in certain embodiments. For Formulas XIV, VI, IX and X, R⁴, R⁶, R⁷ and R¹⁵ are each independently -CH₃, -C2H5, -C3H7, -C4H9, -C5H11, -CF3, -C4F9, -C5F11, -CH2CF3, -CH(CF₃)₂, - CH(CH₃)(CF₃), -C(CH₃)2(CF₃), -C(CF₃)₃, -Si(CH₃)₃, -Si(C₂H₅)3 or -CH₂Si(CH₃)3, -

CH(Si(CH₃)3)₂, -C(Si(CH₃)3)3, -P(CH₃)3, -CH₂P(CH₃)3, -P(O)OH,

-P(O)(OCH₃)₂, -P(O)(OCH₂CH₃)2, -CH(Si(CH₃)3)(P(CH₃)3), -SO2CF3, -SO2C3N2H3,

-C(O)C₃F₇, -CHCHSO2C6H5, -SO2OCH3, or -SO2C6H4CH3. For Formula IX, G may be =0, =NR, =S or =CR₂, where each R is independently an aliphatic, aryl, haloalkyl or haloaryl group. Suitable precursors having four ligands include, but are not limited to, Mo(NtBu)2(OBu)2 and (iPrCp)2MoH2. Suitable precursors having five ligands include, but are not limited to, MoO(OiPr)₄.

[0195] For Formula X, each R⁸ is independently any of the monodentate, ambidentate or bidentate ligands described above. For Formula V, R¹ may be aliphatic, R² may be any of the monodentate, ambidentate, bidentate or tridentate ligands described above, and n may be 1, 2, 3, 4 or 5.

[0196] Low valent molybdenum precursors may also have six ligands. Precursors with six ligands include, but are not limited to, molybdenum hexafluoride (MoFe) and molybdenum hexacarbonyl (Mo(CO)e). In some embodiments, such precursors may have the general formula Mo(X)_P(R¹⁰)q (XII) where each X independently includes chloro, fluoro, bromo or iodo; each R¹⁰ independently includes allyl, allenyl, ethenyl, mesitylenyl, tolyl, xylyl, benzyl, cyclopentadienyl, indenyl, anilinyl, N,N-dimethylanilinyl, tetrahydrofuranyl, piperidinyl, pyrrolyl, pyrrolidinyl, pyridinyl, piperidinyl, imidazolyl, pyrimidinyl, -NO, -CO, -P(CH3)3, -P(CH2CH3)3 or -CNR¹¹, where R¹¹ includes aliphatic, aryl or heterocyclyl; p is 1 to 4; q is 2 to 5; and p + q = 6.

[0197] Low valent molybdenum precursors having six ligands may also be of the formula the Formula (XIII): Mo(R¹²)r(R¹³)s (XIII) where each R¹² independently includes allyl, allenyl, ethenyl, mesitylenyl, tolyl, xylyl, benzyl, cyclopentadienyl, indenyl, anilinyl, N,N- dimethylanilinyl, tetrahydrofuranyl, piperidinyl, pyrrolyl, pyrrolidinyl, pyridinyl, piperidinyl, imidazolyl, pyrimidinyl, -NO, -CO, -P(CH3)3, -P(CH2CH3)3 or -CNR¹⁴, where R¹⁴ includes aliphatic, aryl or heterocyclyl; each R¹³ independently includes trimethylphosphine, triethylphosphine, tri-i-propyl phosphine, triphenylphosphine, tris(trimethylsilyl)phosphine, tris(2-carboxyethyl)phosphine, tris(dimethylamino)phosphine, tris(o-tolyl)phosphine, tris(4- methoxyphenyl)phosphine or tris(2-furyl)phosphine; r is 1 to 6; s is 0 to 5; and r + s = 6.

[0198] FIG. 3B illustrates example structures for low valent molybdenum precursors having six ligands. Structures 1-9 have one or more CNR ligands which may be isocyanoalkyl, isocyanohaloalkyl, isocyanoaryl, or isocyanohaloaryl groups. In some embodiments, R is an aliphatic group such as a haloalkyl, or an aryl group such as haloaryl. In certain embodiments, R may be -CH2CF3, -CH(CF3)2, -CH(CH3)(CF3), or -C(CH3)2(CF3). In certain embodiments, R is a perfluoroalkyl substituent of one to ten carbon atoms such as perfluorinated methyl, ethyl, i- propyl, n-propyl, t-butyl, sec-butyl, n-butyl, cyclopentyl, n-pentyl, cyclohexyl or n-hexyl group. Structures 10-18 have one or more PMei ligands.

[0199] Molybdenum complexes can be prepared using a zero valent starting material such as molybdenum hexacarbonyl. Other synthetic routes include reaction of MoC13(THF)3 with the appropriate ligand followed by reduction and reaction of M0X5 (X = Cl, Br, I) with the appropriate ligand followed by reduction.

[0200] The starting material can be treated with a neutral ligand, such as a thioether (dialkylsulfide), to induce redox neutral ligand exchange. The zero valent starting material can also be treated with a ligand precursor, such as bis(diethylthiocarbamoyl)disulfide or bis(trifluoromethyl)-l,2-dithiete, to induce oxidative addition and form the sulfur-containing complexes described herein.

[0201] The reactions may be conducted in a variety of non-protic solvents. For example the reaction may be conducted in an ether solvent, such as tetrahydrofuran, 2-methyltetrahydrofuran, diethyl ether, methyl-tert-butyl ether, 1,2-dimethoxy ethane, in a hydrocarbon solvent such as toluene, benzene, heptane, hexane, pentane, or in a halocarbon solvent such as chlorobenzene, di chlorobenzene, fluorobenzene, difluorobenzene, dichloromethane, chloroform, etc. The reactions can be conducted in a wide temperature range depending on the boiling point of the solvent and on solubility of the products. In some embodiments, the starting materials, reaction intermediates, and the desired products are unstable toward moisture and oxygen. Accordingly, the reaction process should be conducted using anhydrous and air-free conditions using a protective inert gas, such as nitrogen or argon.

Dimolybdenum Complexes

[0202] In another aspect, precursors for deposition of molybdenum-containing films are dimolybdenum compounds containing a direct molybdenum-molybdenum bond (e.g., a multiple molybdenum-molybdenum bond, such as a double bond, or any multiple bond with a bond order of 2-5). The directly bonded dimolybdenum precursors may be of the structure M02L11 (II), where each occurrence of L is independently a monodentate, ambidentate, bidentate or tridentate ligand as described above, and n is 2 to 6. One example precursor is Mo2(O-isopropyl)e. Other example precursors are shown in FIG. 4. In some embodiments, the dimolybdenum precursor has molybdenum atoms directly connected by a double bond (such as structure 19). In some embodiments, the dimolybdenum precursor has molybdenum atoms directly connected by a triple bond (such as structures 20-23). For structures 20 and 21, R may be an aliphatic group such as an alkyl group, a haloalkyl group or a silyl group. For structure 23, L may be any ligand described above, or may be any one of CO, CNR or PMes (where R is aliphatic, aryl or heterocyclyl) and X is halo. Such precursors are particularly useful for deposition of molybdenum metal and high purity molybdenum metal because it may be easier to reduce such compounds to metallic molybdenum than some monoatomic molybdenum compounds.

[0203] Di-molybdenum precursors described herein can be synthesized using dimolybdenum tetraacetate as a starting material by treatment with a ligand salt such as lithium amidate. In one aspect, a container housing any of the precursors described herein in a solid or liquid form is provided. In another aspect a solution of any of these precursors is provided, where the solvent may include, for example, a high boiling point hydrocarbon solvent, such as a higher alkane. In some embodiments a container holding the molybdenum precursor (in solid or liquid form or in solution) is filled with an inert gas, such as nitrogen (N2), or argon (Ar), to prevent contact of the precursor with air, and possible decomposition due to contact with moisture and/or air. In some embodiments the container is adapted for vaporization of the precursor inside the container. For example, the container may include an inlet and an outlet, where the inlet is adapted to be connected with a source of a carrier gas that can be flowed over or through the precursor thereby assisting in precursor vaporization. The outlet is adapted for removing the carrier gas and the precursor vapor from the container and is configured to be connected to a conduit that can be used to deliver the precursor vapor to the processing chamber. The inlet and the outlet each has a closed position and an open position, and, for example, can include manual valves that can be used to switch from closed to open positions and back. When the container is stored or transported the inlet and the outlet are closed. When the container is fitted to the deposition apparatus for use, the inlet and the outlet valves may be open, and a carrier gas may be flown into the inlet, and out from the outlet carrying the precursor vapor.

[0204] In some embodiments the container has a flow-over design, in which the inlet and the outlet are positioned above the surface of the precursor. For example, in a cylindrical container the inlet and the outlet may be positioned at a similar vertical elevation (e.g., the vertical distance between the inlet and the outlet may be less than about 20% of the cylinder height). In other embodiments the container has a bubbler design, in which the inlet is positioned below the surface of the precursor and the outlet is positioned above the inlet (e.g., above the surface of the precursor). For example, in a cylindrical container the inlet and the outlet may be positioned far from each other in a vertical direction (e.g., the vertical distance between the inlet and the outlet may be more than about 30%, such as more than about 50%, or more than about 80% of the cylinder height.

[0205] A low valent dimolybdenum complex may also contain two molybdenum atoms connected indirectly to each other by a linking moiety. Such precursors may be of the formula LnMo(L’)_mMoLn (III) where each L is independently a monodentate ligand, ambidentate ligand, bidentate ligand or tridentate ligand as described above; L’ is a linking moiety; n is 2 to 6; and m is 1 to 3. The linking moiety L’ may be of the structure -(E)_e- where each E independently includes C(R)_n, NR, Si(R)_n, S, O or P(R)_n; each R independently includes hydrogen, aryl, amino or aliphatic; n is 0, 1 or 2 and e is 1, 2, 3, 4 or 5.

[0206] In some embodiments, the low valent dimolybdenum complex may contain two molybdenum atoms both directly bonded to each other and also connected indirectly to each by a linking moiety as described above. Returning to FIG. 4, example structures 24 and 25 having both types of connections are shown. For structures 24 and 25, L may be any ligand described above, or preferably CO, CNR or PMes (where R is aliphatic, aryl or heterocyclyl) and X is halo. [0207] The molybdenum-containing films, and, particularly, high purity molybdenum metal, provided herein can be used in interconnect metallization (e.g., for filling recessed features to form contacts), in logic gate applications in FinFETs, as adhesion layers or diffusion barriers, and in 3D NAND fabrication. Examples of applications include logic and memory contact fill, DRAM buried wordline fill, vertically integrated memory gate, and wordline fill, and 3-D integration using through-silicon vias (TSV). The resistivity of molybdenum scales better than that of tungsten, and in some embodiments, molybdenum is particularly advantageous metal for filling narrow recessed features, e.g., features with widths of less than about 20 nm.

[0208] In one application, molybdenum metal is used for manufacturing barrierless contacts. In this application, molybdenum metal is deposited directly into the recessed features (contact holes) having widths of about 5 - 100 nm, e.g., about 5 - 20 nm, where the recessed features are formed in the dielectric layer, and include exposed dielectric, such as silicon oxide, silicon nitride, or a low-k material such as silicon oxycarbide at the sidewalls and exposed silicon or silicon germanium at the bottom. In alternative embodiments, the contact hole prior to deposition may be lined with a barrier layer, such as WN, MoN, MoC, or TiN onto which the molybdenum metal is deposited. Additional Molybdenum Precursors

[0209] In one aspect, a precursor for deposition of molybdenum-containing films includes molybdenum, at least one halogen that forms a bond with molybdenum, and at least one organic ligand that includes an element selected from the group consisting of N, O, and S, that forms a bond with molybdenum, with a proviso that the compound is not a molybdenum complex concurrently containing both an imide and a guanidinate organic ligands.

[0210] Such precursors are further described in PCT Publication No. WO 2020/185618, published March 6, 2020 and entitled “Precursors for Deposition of Molybdenum-Containing Films”; the contents of which are hereby incorporated by reference.

[0211] In some embodiments the precursor compound is Mo(X)_m(L)_n, wherein each X is a halogen independently selected from the group consisting of F, Cl, Br, and I; each L is an organic ligand that includes an element selected from the group consisting of N, O, and S, and wherein m is selected from 1-4, and n is selected from 1-3. In some embodiments the organic ligand or ligands are independently selected from amidinates, amines, amidates, iminopyrrolidinates, diazadienes, beta-imino amides, alpha-imino alkoxides, beta-amino alkoxides, beta-diketiminates, beta-ketoiminates, beta-diketonates, thioethers, thiolates, dithiolates, dithiolenes, and pyrazolates, where each may be substituted or unsubstituted.

[0212] In another aspect a precursor for deposition of molybdenum-containing films includes: molybdenum, at least one substituted or unsubstituted l,4-diazabuta-l,3-diene (DAD) ligand bound to molybdenum, and at least one second ligand. The DAD ligand in some embodiments is selected from the group consisting of: neutral DAD,

R-l - |_R

Neutral monoanionic DAD,

R_| ^ |_R

Monoanionic

(Radical anion) and dianionic DAD,

Dianionic wherein each R is independently selected from the group consisting of H, alkyl, fluoroalkyl, alkylsilyl, alkylamino, and alkoxy substituents. The second ligand is selected from the group consisting of an anionic ligand and a neutral ligand, with a proviso that the compound does not include CO as the only second ligand. In some embodiments the precursor compound is Mo(DAD)m(L)n(X)_P, wherein each L is the neutral ligand, each X is an anionic ligand, m is selected from 1-3, n is selected from 0-4, and p is selected from 0-4, wherein n and p are not simultaneously zero. In some embodiments each neutral ligand L is independently selected from the group consisting of CO, an amine, a phosphine, a nitrile, an isonitrile, and a thioether, and each anionic ligand X is independently selected from the group consisting of a halide, an alkyl, an allyl, a cyclopentadienyl, an alkoxide, an amide, and an imide.

[0213] In another aspect, a precursor for deposition of molybdenum-containing films is provided, wherein the precursor is M02L11, wherein each L is independently an amidinate or a guanidinate ligand, n is selected from 2-5, and wherein the precursor comprises a multiple molybdenum-molybdenum bond. In some embodiments the amidinate ligand is:

Amidinate wherein each R is independently selected from the group consisting of of H, alkyl, fluoroalkyl, alkylsilyl, alkylamino, and alkoxy substituents. In some embodiments, the guanidinidate ligand is:

Guanidinate wherein each R is independently selected from the group consisting of H, alkyl, fluoroalkyl, alkylsilyl, alkylamino, and alkoxy substituents.

[0214] In another aspect, a precursor for deposition of molybdenum-containing films is a compound that includes molybdenum and at least one alpha-iminothiolene ligand 23 bound to molybdenum, wherein each R in the alpha-iminothiolene ligand 23 is independently selected from the group consisting of of H, alkyl, fluoroalkyl, alkylsilyl, alkylamino, and alkoxy substituents.

[0215] In some embodiments molybdenum-containing precursors provided herein have a vaporization temperature of 200 °C or less.

[0216] In another aspect, a method of forming a molybdenum-containing layer (e.g., molybdenum metal, molybdenum nitride, molybdenum carbide, molybdenum boride or molybdenum silicide) on a semiconductor substrate is provided, wherein the method includes introducing any of the molybdenum-containing precursors disclosed herein into a process chamber housing the semiconductor substrate; and reacting the molybdenum-containing precursor to form a molybdenum-containing layer on the semiconductor substrate. In some embodiments, the precursors used in deposition are as described above. In one embodiment, the molybdenum- containing precursor is M02L11, wherein each L is independently selected from the group consisting of an amidate, an amidinate and a guanidinate ligands, wherein n is selected from 2-5, and wherein the molybdenum-containing precursor comprises a multiple molybdenum-molybdenum bond.

Tungsten Precursors

[0217] Tungsten can be deposited using a variety of volatile precursors. In some embodiments halogen-containing tungsten precursors, such as WHak, where Hal is a halogen (e.g., F, Cl, Br, and/or I) and x is from 2 to 6, are used. In some embodiments a tungsten chloride or tungsten oxychloride is used. Tungsten chloride includes tungsten pentachloride (WCI5), tungsten hexachloride (WCk), tungsten tetrachloride (WCh), tungsten dichloride (WCh), and mixtures thereof. Tungsten oxychlorides include WOxCly where x and y are numbers greater than 0. In other examples tungsten fluoride, such as tungsten hexafluoride may be used.

Selective Molybdenum or Tungsten Deposition

[0218] Semiconductor fabrication processes may involve formation of metal-containing features having particular a particular structure. While metal features are often filled with copper metal, as devices shrink, alternative materials may be used, such as molybdenum. In some cases, molybdenum may be a suitable metal for filling trenches in back-end-of-line metallization for logic. In such structures, a dielectric substrate may be patterned to thereby form multiple layers within it before etching the dielectric to form a negative feature to then be subsequently filled with metal. Each layer may be used to serve a different purpose. A silicon oxide dielectric layer may be present with a first etch stop layer between it and a first low-k dielectric layer. The first low-k dielectric layer may be adjacent to a second etch stop layer, which may be between the first low- k dielectric layer and a second low-k dielectric layer. The second low-k dielectric layer may be adjacent to a third etch stop layer, which may be between the second low-k dielectric layer and second low-k dielectric layer. From bottom to top (or top to bottom), the layer formation may be as follows: silicon oxide layer, first etch stop layer, first low-k dielectric layer, second etch stop layer, second low-k dielectric layer, third etch stop layer, and third low-k dielectric layer.

[0219] The stack of dielectric layers may be etched to form a negative feature or a via in one or more of the dielectric layers. A negative feature may be defined as a removed portion of a material such that there is a hole or negative space where the portion of the material was removed. This may also be referred to as an “unfilled feature” or “recessed feature.” Non-limiting examples of negative features include trenches, vias, and contact holes. The etch stop layers may have been used to form particular structures for each feature. In some cases, the etch stop layers assist in forming self-align features. Each segment of the feature etched into each layer may have different properties, such as different pitch, different sidewall sloping angles, re-entrant features, and other features. In various embodiments, the feature etched in the silicon oxide layer is first filled with tungsten metal.

[0220] Subsequently, in some logic in BEOL applications, the next layer (the layer that included a first low-k dielectric material on sidewalls of the feature) is referred to as the MO layer. The next layer (the layer that included the second low-k dielectric material on sidewalls of the feature) is referred to as the VO layer. The third layer (the layer that included the third low-k dielectric material on sidewalls of the feature) is referred to as the Ml layer. In some existing logic BEOL applications, the feature is filled with copper for the MO, VO, and Ml layers and copper is formed over the tungsten layer. However, as devices shrink and variables change, other materials, such as molybdenum may be used.

[0221] Molybdenum may be deposited using a pulsed chemical vapor deposition process.

[0222] One aspect involves a method for processing substrates, the method including: providing a substrate having a negative feature in a low-k dielectric; depositing molybdenum into the negative feature to at least partially fill the negative feature with molybdenum over a tungsten layer; and depositing copper over the molybdenum to form a copper layer.

[0223] In various embodiments, the molybdenum is deposited by exposing the substrate to a first hydrogen gas and a molybdenum-containing precursor gas. In some embodiments, the exposures are performed in a process chamber housing the substrate and a purge gas is periodically pulsed during the depositing of the molybdenum to purge excess byproducts from the process chamber. [0224] In any of the above embodiments, the first hydrogen gas may be pulsed. In some embodiments the pulses are temporally sequential pulses. In some embodiments, the temporally sequential pulses of the first hydrogen gas and the purge gas are alternating pulses. In some embodiments, depositing the molybdenum includes pulsing the molybdenum-containing precursor. For example, in some embodiments the pulses of the first hydrogen gas, molybdenum- containing precursor, and purge gas are temporally sequential pulses.

[0225] In any of the above embodiments, the method may also include exposing the substrate to a continuous flow of a second hydrogen gas throughout a duration for depositing the molybdenum into the negative feature.

[0226] In various embodiments, the molybdenum is deposited on a second copper layer, whereby the second copper layer is between the tungsten layer and the molybdenum. For example, in some embodiments, the molybdenum acts as a VO layer, and the second copper layer acts as a MO layer.

[0227] In various embodiments, the molybdenum is deposited directly on tungsten for use as a molybdenum MO layer. For example, in some embodiments, the molybdenum is also deposited on the molybdenum MO layer to form a molybdenum VO layer. In some embodiments, a second copper layer is deposited over the molybdenum MO layer to form a copper VO layer.

[0228] In various of the above embodiments, a barrier layer may be formed between the first copper layer and the molybdenum. For example, in some embodiments, the barrier layer includes cobalt and tantalum oxide. In some embodiments, the cobalt is positioned between the first copper layer and the tantalum oxide.

[0229] Another aspect involves a method for processing substrates, the method including: providing a substrate having a feature thereon to be used to form a line in a semiconductor device; and depositing molybdenum into the feature to at least partially fill the feature with molybdenum by exposing the substrate to a continuous flow of a first hydrogen gas source and a molybdenum- containing precursor, whereby during the continuous flow of the first hydrogen gas source, the substrate is exposed to one or more deposition cycles of the following temporally sequential pulses: (1) pulse of a second hydrogen gas source, (2) pulse of a first purge gas, (3) pulse of a molybdenum-containing precursor source for delivering the molybdenum-containing precursor, and (4) pulse of a second purge gas.

[0230] In various embodiments, the hydrogen gas includes hydrogen, deuterium, hydrogen and argon, hydrogen and helium, hydrogen and oxygen, hydrogen and nitrogen, ammonia, singly deuterated ammonia, doubly deuterated ammonia, triply deuterated ammonia, hydrazine, an alcohol, an aldehyde or combinations thereof. [0231] Another aspect involves an apparatus for processing substrates, the apparatus including: one or more process chambers, each process chamber including a chuck; one or more gas inlets into the process chambers and associated flow-control hardware; and a controller having at least one processor and a memory, whereby the at least one processor and the memory are communicatively connected with one another, the at least one processor is at least operatively connected with the flow-control hardware, and the memory stores computer-executable instructions for controlling the at least one processor to at least control the flow-control hardware to: cause a feature of the substrate to be at least partially filled with molybdenum as a VO or MO layer, and cause deposition of copper over the molybdenum to form a copper Ml layer to completely fill the feature.

[0232] In various embodiments, the controller further includes instructions for causing deposition of molybdenum by causing exposure of the substrate to a first hydrogen gas and a molybdenum-containing precursor gas.

[0233] In various embodiments, the exposures are performed in a process chamber housing the substrate and the controller further includes instructions for causing periodic pulsing of a purge gas during the deposition of the molybdenum to purge excess byproducts from the process chamber.

[0234] In various embodiments, the controller further includes instructions for causing the first hydrogen gas to be pulsed in temporally sequential pulses. In some embodiments, the controller further includes instructions for causing alternating of the pulses of the first hydrogen gas and the purge gas. In some embodiments, the controller further includes instructions for causing pulsing of the molybdenum-containing precursor such that the substrate is exposed to the molybdenum- containing precursor when the substrate is not exposed to the purge gas. In some embodiments, the controller further includes pulsing of the first hydrogen gas such that the substrate is exposed to the first hydrogen gas when the substrate is neither exposed to the purge gas nor the molybdenum-containing precursor.

[0235] In various embodiments, the controller further includes exposing of the substrate to a continuous flow of a second hydrogen gas throughout a duration for depositing the molybdenum into the feature.

[0236] Returning to FIG. 2, subsequent to the selective deposition of operation 210, the protective coating over the metal-containing hardmask applied in operation 206 may optionally be removed.

[0237] FIG. 5 is a process flow diagram depicting another integrated metallization method 500 in accordance with certain disclosed embodiments. The method is similar to method 200 as described above. However, in this integrated method, once the semiconductor substrate has been provided in operation 502, the metal-containing hard mask is first inhibited by exposure to a remote plasma-based pre-cleaning operation and a reagent in operation 504. The conditions for operation 504 are similar to those as described for operation 206 with reference to FIG. 2 above. Subsequent to inhibition operation 504, selective dry etch operation 506 is performed. Dry etch operation 506 is similar to operation 204 as described above with reference to FIG. 2. Optional cap operation 508 and selective deposition operation 510 are similar to operations 208 and 210 respectively, as described above with reference to FIG. 2.

Apparatus

[0238] The deposition methods described herein can be carried out in a variety of apparatuses. A suitable apparatus includes a processing chamber having one or more inlets for introduction of reactants, a substrate holder in the process chamber configured to hold the substrate in place during deposition, and, optionally, a plasma generating mechanism configured for generating a plasma in a process gas. The apparatus may include a controller having program instructions for causing any of the method steps described herein. The deposition methods described herein may be carried out in corresponding atomic layer deposition (ALD) and chemical vapor deposition (CVD) apparatuses.

[0239] For example, in some embodiments the apparatus includes a controller having program instructions that include instructions for: causing an introduction of a molybdenum-containing precursor to the processing chamber, wherein the precursor is any of the precursors described herein; and causing a reaction between the molybdenum-containing precursor and hydrogencontaining gas to form a layer of molybdenum-containing material on a substrate. The controller may include program instructions for causing any of the methods described herein.

[0240] An example of a deposition apparatus suitable for depositing molybdenum-containing films using provided methods is shown in FIG. 6 which schematically illustrates an embodiment of a process station 600 that may be used to deposit material using atomic layer deposition (ALD) and/or chemical vapor deposition (CVD), either of which may be plasma enhanced. In various embodiments, process station 600 is used for pulsed chemical vapor deposition (pCVD). For simplicity, the process station 600 is depicted as a standalone process station having a process chamber body 602 for maintaining a low-pressure environment. However, it will be appreciated that a plurality of process stations 600 may be included in a common process tool environment. Further, it will be appreciated that, in some embodiments, one or more hardware parameters of process station 600, including those discussed in detail below, may be adjusted programmatically by one or more computer controllers. [0241] Process station 600 fluidly communicates with reactant delivery system 601 for delivering process gases to a distribution showerhead 606. Reactant delivery system 601 includes a mixing vessel 604 for blending and/or conditioning process gases for delivery to showerhead 606. One or more mixing vessel inlet valves 620 may control introduction of process gases to mixing vessel 604. Similarly, a showerhead inlet valve 605 may control introduction of process gasses to the showerhead 606.

[0242] Some molybdenum-containing precursors may be stored in solid or liquid form prior to vaporization and subsequent delivery to the process station. For example, the embodiment of FIG. 6 includes a vaporization point 603 for vaporizing solid reactant to be supplied to mixing vessel 604. In some embodiments, vaporization point 603 may be a heated vaporizer. In some embodiments a flow of an inert gas is passed over the heated solid molybdenum precursor, or bubbled through the heated liquid molybdenum precursor, under sub-atmospheric pressure, and carries the precursor vapor to the process chamber. The precursor vapor produced from such vaporizers may condense in downstream delivery piping. Exposure of incompatible gases to the condensed reactant may create small particles. These small particles may clog piping, impede valve operation, contaminate substrates, etc. Some approaches to addressing these issues involve sweeping and/or evacuating the delivery piping to remove residual reactant. However, sweeping the delivery piping may increase process station cycle time, degrading process station throughput. Thus, in some embodiments, delivery piping downstream of vaporization point 603 may be heat traced. In some examples, mixing vessel 604 may also be heat traced. In one non-limiting example, piping downstream of vaporization point 603 has an increasing temperature profile extending from approximately 100°C to approximately 200°C at mixing vessel 604.

[0243] Showerhead 606 distributes process gases toward substrate 612. In the embodiment shown in FIG. 6, substrate 612 is located beneath showerhead 606, and is shown resting on a pedestal 608. It will be appreciated that showerhead 606 may have any suitable shape and may have any suitable number and arrangement of ports for distributing processes gases to substrate 612. While not explicitly shown, in some embodiments the showerhead 606 is a dual plenum showerhead that includes at least two types of conduits, where the first type of conduit is dedicated to delivery of molybdenum-containing precursor vapor, and the second type of conduit is dedicated to delivery of the second (or other) reactant. In these embodiments the molybdenum- containing precursor and the reactant are not allowed to mix in the conduits prior to entry to the process chamber, and do not share the conduits if delivered to the chamber consecutively.

[0244] In some embodiments, a microvolume 607 is located beneath showerhead 606. Performing an ALD and/or CVD process in a microvolume rather than in the entire volume of a process station may reduce reactant exposure and sweep times, may reduce times for altering process conditions (e.g., pressure, temperature, etc.), may limit an exposure of process station robotics to process gases, etc. Example microvolume sizes include, but are not limited to, volumes between 0.1 liter and 2 liters. This microvolume also impacts productivity throughput. While deposition rate per cycle drops, the cycle time also simultaneously reduces. In certain cases, the effect of the latter is dramatic enough to improve overall throughput of the module for a given target thickness of film.

[0245] In some embodiments, pedestal 608 may be raised or lowered to expose substrate 612 to microvolume 607 and/or to vary a volume of microvolume 607. For example, in a substrate transfer phase, pedestal 608 may be lowered to allow substrate 612 to be loaded onto pedestal 608. During a deposition process phase, pedestal 608 may be raised to position substrate 612 within microvolume 607. In some embodiments, microvolume 607 may completely enclose substrate 612 as well as a portion of pedestal 608 to create a region of high flow impedance during a deposition process.

[0246] Optionally, pedestal 608 may be lowered and/or raised during portions the deposition process to modulate process pressure, reactant concentration, etc., within microvolume 607. In one scenario where process chamber body 602 remains at a base pressure during the deposition process, lowering pedestal 608 may allow microvolume 607 to be evacuated. Example ratios of microvolume to process chamber volume include, but are not limited to, volume ratios between 1 :700 and 1: 10. It will be appreciated that, in some embodiments, pedestal height may be adjusted programmatically by a suitable computer controller.

[0247] While the example microvolume variations described herein refer to a height-adjustable pedestal, it will be appreciated that, in some embodiments, a position of showerhead 606 may be adjusted relative to pedestal 608 to vary a volume of microvolume 607. Further, it will be appreciated that a vertical position of pedestal 608 and/or showerhead 606 may be varied by any suitable mechanism within the scope of the present disclosure. In some embodiments, pedestal 608 may include a rotational axis for rotating an orientation of substrate 612. It will be appreciated that, in some embodiments, one or more of these example adjustments may be performed programmatically by one or more suitable computer controllers.

[0248] Returning to the embodiment shown in FIG. 6, showerhead 606 and pedestal 608 electrically communicate with RF power supply 614 and matching network 616 for powering a plasma. In other embodiments apparatuses without a plasma generator are used for depositing molybdenum-containing films using provided methods. In some embodiments, the plasma energy may be controlled by controlling one or more of a process station pressure, a gas concentration, a radio frequency (RF) source power, an RF source frequency, and a plasma power pulse timing. For example, RF power supply 614 and matching network 616 may be operated at any suitable power to form a plasma having a desired composition of radical species. Likewise, RF power supply 614 may provide RF power of any suitable frequency. In some embodiments, RF power supply 614 may be configured to control high- and low-frequency RF power sources independently of one another. Example low-frequency RF frequencies may include, but are not limited to, frequencies between 50 kHz and 700 kHz. Example high-frequency RF frequencies may include, but are not limited to, frequencies between 1.8 MHz and 2.45 GHz. It will be appreciated that any suitable parameters may be modulated discretely or continuously to provide plasma energy for the surface reactions. In one non-limiting example, the plasma power may be intermittently pulsed to reduce ion bombardment with the substrate surface relative to continuously powered plasmas.

[0249] In some embodiments, the plasma may be monitored in-situ by one or more plasma monitors. In one scenario, plasma power may be monitored by one or more voltage, current sensors (e.g., VI probes). In another scenario, plasma density and/or process gas concentration may be measured by one or more optical emission spectroscopy sensors (OES). In some embodiments, one or more plasma parameters may be programmatically adjusted based on measurements from such in-situ plasma monitors. For example, an OES sensor may be used in a feedback loop for providing programmatic control of plasma power. It will be appreciated that, in some embodiments, other monitors may be used to monitor the plasma and other process characteristics. Such monitors may include, but are not limited to, infrared (IR) monitors, acoustic monitors, and pressure transducers.

[0250] In some embodiments, the plasma may be controlled via input/output control (IOC) sequencing instructions. In one example, the instructions for setting plasma conditions for a plasma process phase may be included in a corresponding plasma activation recipe phase of a deposition process recipe. In some cases, process recipe phases may be sequentially arranged, so that all instructions for a deposition process phase are executed concurrently with that process phase. In some embodiments, instructions for setting one or more plasma parameters may be included in a recipe phase preceding a plasma process phase such as for plasma preclean. For example, a first recipe phase may include instructions for setting a flow rate of an inert and/or a reactant gas, instructions for setting a plasma generator to a power set point, and time delay instructions for the first recipe phase. A second, subsequent recipe phase may include instructions for enabling the plasma generator and time delay instructions for the second recipe phase. A third recipe phase may include instructions for disabling the plasma generator and time delay instructions for the third recipe phase. It will be appreciated that these recipe phases may be further subdivided and/or iterated in any suitable way within the scope of the present disclosure.

[0251] In some embodiments, pedestal 608 may be temperature controlled via heater 610. Further, in some embodiments, pressure control for deposition process station 600 may be provided by butterfly valve 618. As shown in the embodiment of FIG. 6, butterfly valve 618 throttles a vacuum provided by a downstream vacuum pump (not shown). However, in some embodiments, pressure control of process station 600 may also be adjusted by varying a flow rate of one or more gases introduced to process station 600.

[0252] FIG. 7 shows a schematic view of an embodiment of a multi-station processing tool 700 with an inbound load lock 702 and an outbound load lock 704, either or both of which may include a remote plasma source. Such tool may be used for processing the substrates using the methods provided herein. A robot 706, at atmospheric pressure, is configured to move wafers from a cassette loaded through a pod 708 into inbound load lock 702 via an atmospheric port 710. A wafer is placed by the robot 706 on a pedestal 712 in the inbound load lock 702, the atmospheric port 710 is closed, and the load lock is pumped down. Where the inbound load lock 702 includes a remote plasma source, the wafer may be exposed to a remote plasma treatment in the load lock prior to being introduced into a processing chamber 714. Further, the wafer also may be heated in the inbound load lock 702 as well, for example, to remove moisture and adsorbed gases. Next, a chamber transport port 716 to processing chamber 714 is opened, and another robot (not shown) places the wafer into the reactor on a pedestal of a first station shown in the reactor for processing. While the embodiment depicted in FIG. 7 includes load locks, it will be appreciated that, in some embodiments, direct entry of a wafer into a process station may be provided.

[0253] The depicted processing chamber 714 includes four process stations, numbered from 1 to 4 in the embodiment shown in FIG. 7. Each station has a heated pedestal (shown at 718 for station 1), and gas line inlets. It will be appreciated that in some embodiments, each process station may have different or multiple purposes. While the depicted processing chamber 714 includes four stations, it will be understood that a processing chamber according to the present disclosure may have any suitable number of stations. For example, in some embodiments, a processing chamber may have five or more stations, while in other embodiments a processing chamber may have three or fewer stations.

[0254] FIG. 7 also depicts an embodiment of a wafer handling system 790 for transferring wafers within processing chamber 714. In some embodiments, wafer handling system 790 may transfer wafers between various process stations and/or between a process station and a load lock. It will be appreciated that any suitable wafer handling system may be employed. Non-limiting examples include wafer carousels and wafer handling robots. FIG. 7 also depicts an embodiment of a system controller 750 employed to control process conditions and hardware states of process tool 700. System controller 750 may include one or more memory devices 756, one or more mass storage devices 754, and one or more processors 752. Processor 752 may include a CPU or computer, analog and/or digital input/output connections, stepper motor controller boards, etc. [0255] In some embodiments, system controller 750 controls all of the activities of process tool 700. System controller 750 executes system control software 758 stored in mass storage device 754, loaded into memory device 756, and executed on processor 752. System control software 758 may include instructions for controlling the timing, mixture of gases, chamber and/or station pressure, chamber and/or station temperature, purge conditions and timing, wafer temperature, RF power levels, RF frequencies, substrate, pedestal, chuck and/or susceptor position, and other parameters of a particular process performed by process tool 700. System control software 758 may be configured in any suitable way. For example, various process tool component subroutines or control objects may be written to control operation of the process tool components necessary to carry out various process tool processes in accordance with the disclosed methods. System control software 758 may be coded in any suitable computer readable programming language.

[0256] In some embodiments, system control software 758 may include input/output control (IOC) sequencing instructions for controlling the various parameters described above. For example, each phase of an ALD process may include one or more instructions for execution by system controller 750. The instructions for setting process conditions for an ALD process phase may be included in a corresponding ALD recipe phase. In some embodiments, the ALD recipe phases may be sequentially arranged, so that all instructions for an ALD process phase are executed concurrently with that process phase.

[0257] Other computer software and/or programs stored on mass storage device 754 and/or memory device 756 associated with system controller 750 may be employed in some embodiments. Examples of programs or sections of programs for this purpose include a substrate positioning program, a process gas control program, a pressure control program, a heater control program, and a plasma control program.

[0258] A substrate positioning program may include program code for process tool components that are used to load the substrate onto pedestal 718 and to control the spacing between the substrate and other parts of process tool 700.

[0259] A process gas control program may include code for controlling gas composition and flow rates and optionally for flowing gas into one or more process stations prior to deposition in order to stabilize the pressure in the process station. The process gas control program may include code for controlling gas composition and flow rates within any of the disclosed ranges. A pressure control program may include code for controlling the pressure in the process station by regulating, for example, a throttle valve in the exhaust system of the process station, a gas flow into the process station, etc. The pressure control program may include code for maintaining the pressure in the process station within any of the disclosed pressure ranges.

[0260] A heater control program may include code for controlling the current to a heating unit that is used to heat the substrate. Alternatively, the heater control program may control delivery of a heat transfer gas (such as helium) to the substrate. The heater control program may include instructions to maintain the temperature of the substrate within any of the disclosed ranges.

[0261] A plasma control program may include code for setting RF power levels and frequencies applied to the process electrodes in one or more process stations, for example using any of the RF power levels disclosed herein. The plasma control program may also include code for controlling the duration of each plasma exposure.

[0262] In some embodiments, there may be a user interface associated with system controller 750. The user interface may include a display screen, graphical software displays of the apparatus and/or process conditions, and user input devices such as pointing devices, keyboards, touch screens, microphones, etc.

[0263] In some embodiments, parameters adjusted by system controller 750 may relate to process conditions. Non-limiting examples include process gas composition and flow rates, temperature, pressure, plasma conditions (such as RF power levels, frequency, and exposure time), etc. These parameters may be provided to the user in the form of a recipe, which may be entered utilizing the user interface.

[0264] Signals for monitoring the process may be provided by analog and/or digital input connections of system controller 750 from various process tool sensors. The signals for controlling the process may be output on the analog and digital output connections of process tool 700. Nonlimiting examples of process tool sensors that may be monitored include mass flow controllers, pressure sensors (such as manometers), thermocouples, etc. Appropriately programmed feedback and control algorithms may be used with data from these sensors to maintain process conditions.

[0265] Any suitable chamber may be used to implement the disclosed embodiments. Two or more of the stations may perform the same functions. Similarly, two or more stations may perform different functions. Each station can be designed/configured to perform a particular function/method as desired.

[0266] As described above, one or more process stations may be included in a multi-station processing tool. FIG. 8 depicts an example processing apparatus according to disclosed embodiments. Tool 800 includes a first processing chamber 802 and a second processing chamber 804. The first processing chamber 802 includes a plurality of processing stations, four stations 880A-D, that each may process a wafer. The first processing chamber 802 is configured to perform plasma treatment operations on the wafers. The second processing chamber 804 is configured to perform deposition on the wafer and may be considered a deposition chamber. The second processing chamber 804 also includes a plurality of processing stations, four stations 882A-D, that each may process a wafer. The first and second processing chambers 802 and 804 may be considered multi-station processing chambers.

[0267] Tool 800 also includes a wafer transfer unit configured to transport one or more wafers within the tool 800. Additional features of tool 800 will be discussed in greater detail below, and various features are discussed here with respect to some of the described techniques. In the depicted illustration, the wafer transfer unit includes a first robotic arm unit 808 in a first wafer transfer module 810 and a second robotic arm unit 812 in a second wafer transfer module 814 that may be considered an equipment front end module (EFEM) configured to received containers for wafers, such as a front opening unified module (FOUP) 816. The first robotic arm unit 808 is configured to transport a wafer between the first processing chamber 802 and the second processing chamber 804, and between the second the second robotic arm unit 812. The second robotic arm unit 812 is configured to transport the wafer between a FOUP and the first robotic arm unit 808. After a wafer has been treated in the first processing chamber 802, the wafer transfer unit is able to transfer the wafer from the first processing chamber 802, to the second processing chamber 804 where one or more layers of encapsulation material may be deposited on one or more wafers.

[0268] Similar to above, the first wafer transfer module 810 may a vacuum transfer module (VTM). Airlock 820, also known as a loadlock or transfer module, is shown and may be individually optimized to perform various fabrication processes. The tool 800 also includes a FOUP 816 that is configured to lower the pressure of the tool 800 to a vacuum or low pressure, e.g., between about 1 mTorr and about 10 Torr, and maintain the tool 800 at this pressure. This includes maintaining the first and second processing chambers 802 and 804, and the first wafer transfer module 810 at the vacuum or low pressure. The second wafer transfer module 814 may be at a different pressure, such as atmospheric. As the wafer is transferred throughout the tool 800, it is therefore maintained at the vacuum or low pressure. For example, as the wafer is transferred from the first processing chamber 802, into the first wafer transfer module 810, and to the second processing chamber 804, the wafer is maintained at the vacuum or low pressure and not exposed to atmospheric pressure. [0269] In a further example, a substrate is placed in one of the FOUPs 818 and the second robot arm unit 812, or front-end robot, transfers the substrate from the FOUP 818 to an aligner, which allows the substrate to be properly centered before it is etched, or deposited upon, or otherwise processed. After being aligned, the substrate is moved by the second robot arm unit 812 into the airlock 820. Because airlock modules have the ability to match the environment between an ATM and a VTM, the substrate is able to move between the two pressure environments without being damaged. From the airlock 820, the substrate is moved by the first robot arm unit 808 through the first wafer transfer module 810, or VTM 810, and into the first processing chamber 802. In order to achieve this substrate movement, the first robot arm unit 808 uses end effectors on each of its arms.

[0270] FIG. 8 also depicts an embodiment of a system controller 829 employed to control process conditions and hardware states of tool 800. System controller 829 may include one or more memory devices (not shown), one or more mass storage devices (not shown), and one or more processors (not shown). Processors may include a CPU or computer, analog, and/or digital input/output connections, stepper motor controller boards, etc. System controller 829 may have one or more features such as those described above with respect to system controller 750.

[0271] A process station may be included in a single-station chamber or single-chamber tool such as shown in FIG. 9. FIG. 9 depicts an example processing apparatus according to disclosed embodiments. Tool 900 includes a processing chamber 914 which includes a processing station 990 may process a wafer. The processing chamber 914 is configured to deposit molybdenum, perform preclean, perform degas, and/or perform soaking and the like.

[0272] Tool 900 also includes a wafer transfer unit configured to transport wafers within the tool 900. Additional features of tool 900 will be discussed in greater detail below, and various features are discussed here with respect to some of the described techniques. In the depicted illustration, the wafer transfer unit includes a first robotic arm unit 926 in a first wafer transfer module and a second robotic arm unit 906 in a second wafer transfer module that may be considered an equipment front end module (EFEM) configured to received containers for wafers, such as a front opening unified module (FOUP) 908. The first robotic arm unit 926 is configured to transport a wafer between the processing chamber 914 and the second robotic arm unit via module 904 which may hold multiple wafers such as shown in module 902 with substrate 912. The second robotic arm unit 906 is configured to transport the wafer between a FOUP and module 904, or from module 902 to FOUP. After a wafer has been prepared in the module 904, the wafer transfer unit is able to transfer the wafer to first processing chamber 914 for deposition and optional anneal in situ. [0273] Similar to above, the first wafer transfer module may a vacuum transfer module (VTM). Airlock or module 904, also known as a loadlock, is shown and may be individually optimized to perform various fabrication processes. The tool 900 also includes a FOUP 908 that is configured to lower the pressure of the tool 900 to a vacuum or low pressure, e.g., between about 10 Torr to about 150 Torr, and maintain the tool 900 at this pressure. This includes maintaining the processing chamber 914, and the first wafer transfer module at the vacuum or low pressure. The second wafer transfer module may be at a different pressure, such as atmospheric. As the wafer is transferred throughout the tool 900, it is therefore maintained at the vacuum or low pressure. [0274] In a further example, a substrate is placed in one of the FOUPs 908 and the second robot arm unit 906, or front-end robot, transfers the substrate from the FOUP 918 to an aligner, which allows the substrate to be properly centered before it is etched, or deposited upon, or otherwise processed. After being aligned, the substrate is moved by the second robot arm unit 906 into the airlock module 904. Because airlock modules have the ability to match the environment between an ATM and a VTM, the substrate is able to move between the two pressure environments without being damaged. From the airlock module 904, the substrate is moved by the first robot arm unit 926 through the first wafer transfer module, or VTM, and into the processing chamber 914. In order to achieve this substrate movement, the first robot arm unit 926 uses end effectors on each of its arms.

[0275] FIG. 9 also depicts an embodiment of a system controller 950 employed to control process conditions and hardware states of process tool 900. System controller 950 may include one or more memory devices 956, one or more mass storage devices 954, system control software 958, and one or more processors 952. Processor 952 may include a CPU or computer, analog and/or digital input/output connections, stepper motor controller boards, etc. In some embodiments, system controller 950 includes machine-readable instructions for performing operations such as those described above with respect to FIGS. 7 and 8.

Further Implementations

[0276] The apparatus and processes described herein may be used in conjunction with lithographic patterning tools or processes, for example, for the fabrication or manufacture of semiconductor devices, displays, LEDs, photovoltaic panels, and the like. Typically, though not necessarily, such apparatus and processes will be used or conducted together in a common fabrication facility. Lithographic patterning of a film typically comprises some or all of the following steps, each step enabled with a number of possible tools: (1) application of photoresist on a work piece, i.e., a substrate, using a spin-on or spray-on tool; (2) curing of photoresist using a hot plate or furnace or UV curing tool; (3) exposing the photoresist to visible or UV or x-ray light with a tool such as a wafer stepper; (4) developing the resist so as to selectively remove resist and thereby pattern it using a tool such as a wet bench; (5) transferring the resist pattern into an underlying film or work piece by using a dry or plasma-assisted etching tool; and (6) removing the resist using a tool such as an RF or microwave plasma resist stripper.

Conclusion

[0277] Although the foregoing embodiments have been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be practiced within the scope of the appended claims. It should be noted that there are many alternative ways of implementing the processes, systems, and apparatus of the present embodiments. Accordingly, the present embodiments are to be considered as illustrative and not restrictive, and the embodiments are not to be limited to the details given herein.

Claims

CLAIMS What is claimed is:

1. An integrated method comprising: providing a semiconductor substrate comprising a via, via sidewalls composed of dielectric material, a conductive metal layer below the via, a metal overlayer on the conductive metal layer, a metal oxide or metal nitride etch stop layer on the metal overlayer, and field regions covered with a metal-containing hardmask in a processing chamber; performing a selective dry etch to remove the metal oxide or metal nitride etch stop layer without corroding the conductive metal layer, the via sidewalls, the metal-containing hardmask, or the metal overlayer; and exposing the metal-containing hardmask to a remote plasma pre-cleaning operation and a reagent to form a protective coating over the metal-containing hardmask.

2. The method of claim 1, further comprising: selectively depositing molybdenum or tungsten in the via over the conductive metal layer by exposure to a via metallization precursor and a hydrogen gas source, wherein the protective coating prevents deposition of molybdenum or tungsten onto the metal-containing hardmask.

3. The method of claim 1, wherein performing a selective dry etch to remove the metal oxide or metal nitride etch stop layer comprises volatilizing the metal oxide or metal nitride etch stop layer by a thermal atomic layer etch.

4. The method of claim 3, wherein the thermal atomic layer etch comprises reacting the metal oxide or metal nitride etch stop layer with a halogen-containing reactant to form a halogenated etch stop layer and exposure of the halogenated etch stop layer to an organometal reactant to produce a volatile organohalide.

5. The method of claim 1, wherein the metal oxide or metal nitride etch stop layer comprises aluminum nitride or aluminum oxide.

6. The method of claim 1, wherein the remote plasma pre-cleaning operation comprises at least one of nitridation, carbidization, silicidation, phosphorulation, fluorination, chlorination, bromination, iodination, reduction, or oxidation.

7. The method of claim 1, wherein the reagent comprises a self-assembled monolayer precursor, an alkyl halide, an aromatic compound, a beta diketone, an alkylsilane, or a silicon-containing precursor.

8. The method of claim 1, wherein exposing the metal-containing hardmask to a remote plasma pre-cleaning operation and a reagent comprises simultaneous exposure of the metal-containing hardmask to the remote plasma pre-cleaning operation and the reagent, or sequential exposure of the metal-containing hardmask to the remote plasma pre-cleaning operation and the reagent.

9. The method of claim 1, wherein the metal-containing hardmask comprises tungsten, titanium, molybdenum, tantalum, or a combination thereof.

10. The method of claim 1, further comprising a silicon oxide underlayer below the metal-containing hardmask.

11. The method of claim 1, further comprising removing the protective coating from the metal-containing hardmask.

12. The method of claim 1, further comprising capping the metal overlayer with a metal cap or metal-containing cap without capping the metal-containing hardmask.

13. The method of claim 1, wherein the via metallization precursor comprises a molybdenum-containing precursor.

14. The method of claim 19, wherein the molybdenum-containing precursor comprises a molybdenum halide or a molybdenum oxyhalide.

15. An integrated method for selective molybdenum or tungsten deposition comprising: providing a semiconductor substrate comprising a via, via sidewalls composed of dielectric material, a conductive metal layer below the via, a metal overlayer on the conductive metal layer, a metal oxide or metal nitride etch stop layer on the metal overlayer, and field regions covered with a metal-containing hardmask in a processing chamber; exposing the metal-containing hardmask to a remote plasma pre-cleaning operation and a reagent to form a protective coating over the metal-containing hardmask; and performing a selective dry etch to remove the metal oxide or metal nitride etch stop layer without corroding the conductive metal layer, the via sidewalls, the metal-containing hardmask, or the metal overlayer.

16. The method of claim 15, further comprising selectively depositing molybdenum or tungsten in the via over the conductive metal layer by exposure to a via metallization precursor and a hydrogen gas source; and wherein the protective coating prevents deposition of molybdenum or tungsten onto the metal-containing hardmask.

17. An apparatus for selective molybdenum or tungsten deposition comprising: a processing chamber; a substrate holder in the processing chamber; one or more gas inlets for flowing gases into the processing chamber; a vacuum source for removing gases from the processing chamber; a plasma generator for generating a plasma within the processing chamber; an etching module configured to perform a selective dry etch; an inhibition module comprising a remote plasma source and configured to form a protective coating; a metal deposition module configured to deposit molybdenum or tungsten; and one or more controllers comprising machine-readable instructions for operating the one or more gas inlets, vacuum source, and plasma generator to deposit molybdenum or tungsten onto a semiconductor substrate, the machine-readable instructions of the one or more controllers comprising instructions for: causing performance of a selective dry etch to remove a metal oxide or metal nitride etch stop layer without corroding a conductive metal layer or a metal overlayer; causing exposure of a metal-containing hardmask to a remote plasma pre-cleaning operation and a reagent to form a protective coating over the metal-containing hardmask; and causing selective deposition of molybdenum or tungsten in a via over the conductive metal layer by exposure to a via metallization precursor; and wherein the protective coating prevents deposition of molybdenum or tungsten onto the metalcontaining hardmask; and wherein the apparatus is configured to transfer a substrate between each of the etching module, the inhibition module, and the metal deposition module under vacuum.

18. The apparatus of claim 17, wherein the etching module, the inhibition module, and the metal deposition module are integrated into the same process chamber.

19. The apparatus of claim 17, further comprising a capping module configured to cap the metal overlayer with a metal cap or metal -containing cap.

20. The apparatus of claim 19, wherein the etching module, the inhibition module, the capping module, and the metal deposition module are integrated into the same process chamber.

21. An integrated method comprising: providing a semiconductor substrate comprising a via, via sidewalls composed of dielectric material, a conductive metal layer below the via, a metal overlayer on the conductive metal layer, a metal oxide or metal nitride etch stop layer on the metal overlayer, and field regions covered with a metal-containing hardmask, and a protective coating over the metalcontaining hardmask in a processing chamber; performing a selective dry etch to remove the metal oxide or metal nitride etch stop layer without corroding the conductive metal layer, the via sidewalls, the metal-containing hardmask, or the metal overlayer; and selectively depositing molybdenum or tungsten in the via over the conductive metal layer by exposure to a via metallization precursor and a hydrogen gas source, wherein the protective coating prevents deposition of molybdenum or tungsten onto the metal-containing hardmask.