Precursor for depositing molybdenum-containing film

Abstract

To provide a method and a precursor for depositing a molybdenum-containing film.SOLUTION: A molybdenum-containing film is deposited on a semiconductor substrate using the reaction of the molybdenum-containing precursor in an ALD and CVD process. In some embodiments, a molybdenum metal film having a low carbon and nitrogen contamination level is deposited using the precursor; in some embodiments, a film is deposited using fluorine-free precursors without using an etching stop layer in the presence of an exposure silicon-containing layer; in some embodiments, the precursor includes: at least one organic ligand including molybdenum, at least one halogen forming a bond with the molybdenum and an element selected from a group consisting of N, O and S and forming a bond with the molybdenum; and in another embodiment, the precursor has at least one sulfur-containing ligand and is preferably a molybdenum compound with no molybdenum-carbon bond.SELECTED DRAWING: Figure 4B

Description

[Technical field]

[0001] [Incorporated by reference] A PCT application is being filed contemporaneously herewith as a part of this application, and each application identified in that contemporaneously filed PCT application to which this application claims benefit or priority is hereby incorporated by reference in its entirety for all purposes.

[0002] The present invention relates to methods for manufacturing semiconductor devices. In particular, embodiments of the present invention relate to precursors used in the deposition of molybdenum-containing films in semiconductor processing. [Background technology]

[0003] In integrated circuit (IC) manufacturing, deposition and etching techniques are used to pattern materials, such as forming metal lines embedded in dielectric layers. Some patterning methods require conformal deposition of materials, where the deposited layer must follow the contours of convex and / or concave features on the substrate surface. Atomic layer deposition (ALD) is often the preferred method for forming conformal films on substrates, since ALD relies on the adsorption of one or more reactants (precursors) to the substrate surface, followed by chemical conversion of the adsorbed layer into the desired material. ALD utilizes sequential reactions that occur at the substrate surface, are separated in time, and are usually limited by the amount of adsorbed reactants, providing thin conformal layers with excellent step coverage.

[0004] Chemical vapor deposition (CVD) is another deposition method that is widely used in semiconductor processing. In CVD, the reaction occurs within the volume of the process chamber and is not limited by the amount of reactants adsorbed on the substrate. As a result, CVD deposited films are often less conformal than ALD deposited films. CVD is typically used in applications where step coverage is less critical.

[0005] ALD and CVD may use a plasma to facilitate the reaction of deposition precursors to form the desired film. Processes that utilize a plasma are known as plasma-enhanced ALD (PEALD) and plasma-enhanced CVD (PECVD). Processes that do not use a plasma are called thermal ALD and thermal CVD.

[0006] ALD and CVD are most commonly used for the deposition of silicon-containing films such as silicon oxide, silicon nitride, and silicon carbide, and these methods are also suitable for the deposition of some metals, particularly tungsten and cobalt.

[0007] The description of the background art provided herein is intended to provide a general background to the present disclosure, and the work of the inventors named herein, to the extent described in this Background section, together with aspects of the description that would not ordinarily be considered prior art at the time of filing, are not admitted, expressly or impliedly, as prior art to the present disclosure. Summary of the Invention

[0008] Metallic molybdenum, molybdenum nitride (MoN x ), molybdenum carbide (MoC x ), Molybdenum boride (MoB x ), molybdenum disilicide (MoSi x ), and combinations thereof (e.g., molybdenum carbonitride (MoC x N y ), molybdenum borocarbide (MoB x C y Methods are provided for depositing molybdenum-containing films, such as SiO 2 , SiO 3 , SiO 4 , and SiO 5 . Precursors for the deposition of molybdenum-containing films are also provided.

[0009] In one aspect, a precursor for deposition of a molybdenum-containing film comprises molybdenum, at least one halogen that forms a bond with the molybdenum, and at least one organic ligand that comprises an element selected from the group consisting of N, O, and S that forms a bond with the molybdenum, with the proviso that the compound is not a molybdenum complex that simultaneously contains both imide and guanidinate organic ligands. In some embodiments, the precursor compound is Mo(X). m (L) n wherein each X is independently a halogen selected from the group consisting of F, Cl, Br, and I; each L is an organic ligand comprising an element selected from the group consisting of N, O, and S, m is selected from 1 to 4, and n is selected from 1 to 3. In some embodiments, the organic ligand or ligands are independently selected from amidinates, amines, amidates, iminopyrrolidinates, diazadienes, β-iminoamides, α-iminoalkoxides, β-aminoalkoxides, β-diketiminates, β-ketoiminates, β-diketonates, thioethers, thiolates, dithiolates, dithiolenes, and pyrazolates, each of which may be substituted or unsubstituted.

[0010] In another aspect, a precursor for deposition of a molybdenum-containing film comprises molybdenum, at least one substituted or unsubstituted 1,4-diazabuta-1,3-diene (DAD) ligand bonded to the molybdenum, and at least one second ligand. The DAD ligand, in some embodiments, is neutral DAD, [ka]

[0011] Monoanionic DAD, [ka]

[0012] and dianionic DAD, [ka]

[0013] where 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 anionic ligands and neutral ligands, with the 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 a neutral ligand, each X is an anionic ligand, m is selected from 1 to 3, n is selected from 0 to 4, and p is selected from 0 to 4, and n and p are not simultaneously zero. In some embodiments, each neutral ligand L is independently selected from the group consisting of CO, amines, phosphines, nitriles, isonitriles, and thioethers, and each anionic ligand X is independently selected from the group consisting of halides, alkyls, allyls, cyclopentadienyls, alkoxides, amides, and imides.

[0014] In another aspect, a precursor for deposition of a molybdenum-containing coating is provided, the precursor comprising Mo2L n wherein each L is independently an amidinate or guanidinate ligand, n is selected from 2 to 5, and the precursor contains a plurality of molybdenum-molybdenum bonds. In some embodiments, the amidinate ligand is [ka]

[0015] where each R is independently selected from the group consisting of H, alkyl, fluoroalkyl, alkylsilyl, alkylamino, and alkoxy substituents. In some embodiments, the guanidinate ligand is [ka]

[0016] where each R is independently selected from the group consisting of H, alkyl, fluoroalkyl, alkylsilyl, alkylamino, and alkoxy substituents.

[0017] In another embodiment, a precursor for deposition of a molybdenum-containing film is a compound comprising molybdenum and at least one α-iminothiolene ligand 23 bonded to the molybdenum, where each R in the α-iminothiolene ligand 23 is independently selected from the group consisting of H, alkyl, fluoroalkyl, alkylsilyl, alkylamino, and alkoxy substituents.

[0018] In some embodiments, the molybdenum-containing precursors provided herein have a vaporization temperature of less than 200°C.

[0019] In another aspect, a method is provided for forming a molybdenum-containing layer (e.g., molybdenum metal, molybdenum nitride, molybdenum carbide, molybdenum boride, or molybdenum silicide) on a semiconductor substrate, the method comprising introducing any of the molybdenum-containing precursors disclosed herein into a process chamber containing 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 for deposition are as described above. In one embodiment, the molybdenum-containing precursor is Mo2L n wherein each L is independently selected from the group consisting of amidate, amidinate, and guanidinate ligands; n is selected from 2 to 5; and the molybdenum-containing precursor comprises a plurality of molybdenum-molybdenum bonds.

[0020] In some embodiments, a method is provided for selectively depositing a molybdenum-containing layer on a dielectric layer in the presence of an exposed metal layer on a semiconductor substrate, the method comprising: (a) providing a semiconductor substrate having an exposed metal layer and an exposed dielectric layer, the dielectric layer having an exposed Si-OH bond; (b) contacting the semiconductor substrate with a molybdenum-containing precursor, the precursor comprising a ligand having a deprotonated nitrogen that forms a bond with molybdenum; and (c) reacting the molybdenum-containing precursor to selectively form a molybdenum-containing layer on the dielectric layer.

[0021] In some embodiments, a method is provided for selectively depositing a molybdenum-containing layer on a metal layer in the presence of an exposed dielectric layer on a semiconductor substrate, the method comprising: (a) providing a semiconductor substrate having an exposed metal layer and an exposed dielectric layer; (b) contacting the semiconductor substrate with a molybdenum-containing precursor, the precursor comprising molybdenum and at least one of the radical anion ligands dithiolene 21 and α-iminothiolene 23 bound to molybdenum, where each R is independently selected from H, alkyl, fluoroalkyl, alkylamino, alkylsilyl, and alkoxy; and (c) reacting the molybdenum-containing precursor to selectively form a molybdenum-containing layer on the metal layer.

[0022] In some embodiments, a method of forming a molybdenum metal layer (e.g., a high purity molybdenum metal layer) on a semiconductor substrate is provided. In some embodiments, the method includes (a) introducing a molybdenum-containing precursor into a process chamber containing a semiconductor substrate, and (b) reacting the molybdenum-containing precursor to form molybdenum metal on the semiconductor substrate. The molybdenum-containing precursor can be any precursor described herein. In one aspect, the precursor is a compound comprising molybdenum, at least one halogen that forms a bond with the molybdenum, and at least one organic ligand comprising an element selected from the group consisting of N, O, and S that forms a bond with the molybdenum. In another aspect, the precursor is a compound comprising molybdenum and at least one sulfur-containing ligand that forms a molybdenum-sulfur bond with the molybdenum, the compound not comprising a molybdenum-carbon bond. In another aspect, the molybdenum precursor is a compound comprising a molybdenum-molybdenum multiple bond. The precursors can be reacted with at least one reactant selected from the group consisting of hydrogen (H2), ammonia (NH3), hydrazine, amines, borane (B2H6), silane (SiH4), disilane (Si2H6), water, alcohol, H2S, and thiols, optionally with plasma activation. In some embodiments, the precursors are first reacted with one reactant from the group, and then reacted with a different reactant from the group. For example, the precursors can be reacted with water, thiols, or H2S, and then treated with H2, where the H2 treatment can be performed with or without plasma. The reaction occurs only on the surface of the substrate in some embodiments. In other embodiments, the reaction can occur within the volume of the process chamber.

[0023] The method can be used to deposit molybdenum metal with a low carbon content, such as molybdenum metal having a carbon content of less than about 5 atomic %.

[0024] In another aspect, a system for processing a semiconductor substrate is provided, the system including: (a) a process chamber having a substrate holder and one or more inlets for introducing reactants into the process chamber; and (b) a system controller including program instructions for performing any of the methods provided herein. In some embodiments, the system controller includes program instructions for: (i) causing the introduction of a molybdenum-containing precursor described herein into the process chamber; and (ii) causing a reaction of the molybdenum-containing precursor to form a molybdenum-containing layer on the semiconductor substrate. In some embodiments, the system controller includes program instructions for: (i) causing the introduction of a molybdenum-containing precursor into the process chamber, where the molybdenum-containing precursor is Mo2L n wherein each L is independently selected from the group consisting of amidate, amidinate, and guanidinate ligands, n is 2-5, and the molybdenum-containing precursor comprises a plurality of molybdenum-molybdenum bonds; and (ii) program instructions for causing reaction of the molybdenum-containing precursor to form a molybdenum-containing layer on the semiconductor substrate. In some embodiments, the system controller includes program instructions for (i) causing introduction of a molybdenum-containing precursor into the process chamber, wherein the molybdenum-containing precursor comprises molybdenum and at least one organic ligand bonded to the molybdenum, the organic ligand comprising at least one of N, O, and S; and (ii) causing reaction of the molybdenum-containing precursor to form a molybdenum-containing layer on the semiconductor substrate. In some embodiments, the molybdenum-containing precursor comprises molybdenum and at least one sulfur-containing ligand bonded to the molybdenum.

[0025] In another aspect, a non-transitory computer readable medium is provided that includes program instructions for control of a deposition tool, the program instructions including code for causing any of the methods described herein.

[0026] The methods and apparatus described herein can be integrated with processes and apparatus for performing photolithographic patterning. In one aspect, a system is provided, the system including any of the apparatus and steppers described herein.

[0027] The molybdenum-containing precursors described herein can be used in ALD and CVD for the deposition of molybdenum-containing films in a wide variety of applications. In some embodiments, the precursors are used to form conformal films. In other embodiments, the precursors are used to fill recessed features with molybdenum-containing materials (e.g., molybdenum metal). For example, the provided precursors and methods can be used to fill contact holes with high purity molybdenum metal. The provided precursors can be used to deposit high purity molybdenum with low contamination levels of other elements such as O, N, and S.

[0028] These and other aspects of the implementations of the subject matter described herein are set forth in the accompanying drawings and the description that follows. [Brief description of the drawings]

[0029] [Figure 1A] 1 is an example of a ligand that can be used in a molybdenum precursor according to one embodiment provided herein.

[0030] [Figure 1B] 1 is an example of a sulfur-containing ligand that can be used in the molybdenum precursor according to one embodiment provided herein.

[0031] [Diagram 2] 1 is a list of examples of molybdenum precursors according to one embodiment provided herein.

[0032] [Diagram 3] 1 shows chemical reactions that can be used to synthesize the molybdenum precursors provided herein.

[0033] [Figure 4A]FIG. 1 is a process flow diagram of a method of forming a molybdenum-containing coating according to one embodiment provided herein.

[0034] [Figure 4B] FIG. 1 is a process flow diagram of a method for forming a molybdenum metal film according to one embodiment provided herein.

[0035] [Diagram 5] 1 shows a reaction illustrating the selective deposition of a molybdenum-containing film onto a dielectric in the presence of a metal.

[0036] [Figure 6A] 1 is a cross-sectional view of a substrate during deposition of a molybdenum-containing film according to one embodiment provided herein. [Figure 6B] 1 is a cross-sectional view of a substrate during deposition of a molybdenum-containing film according to one embodiment provided herein. [Figure 6C] 1 is a cross-sectional view of a substrate during deposition of a molybdenum-containing film according to one embodiment provided herein.

[0037] [Figure 7] FIG. 1 is a schematic diagram of an apparatus suitable for depositing a molybdenum-containing coating according to one embodiment provided herein.

[0038] [Figure 8] FIG. 1 is a schematic diagram of a multi-station processing system according to one embodiment provided herein.

[0039] [Figure 9] FIG. 1 is a schematic diagram of a multi-station processing system according to one embodiment provided herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] Methods and precursors are provided for depositing molybdenum-containing films on semiconductor substrates. These methods and precursors can be used, for example, to deposit blanket molybdenum-containing films on planar substrates, to deposit conformal molybdenum-containing layers on substrates having one or more recessed or protruding features, and to fill recessed features with molybdenum-containing materials. In some embodiments, methods and precursors are provided for selectively depositing a molybdenum-containing layer on a dielectric layer in the presence of exposed metal, or for selectively depositing a molybdenum-containing layer on a metal in the presence of exposed dielectric.

[0041] The method includes the steps of: x ), molybdenum carbide (MoC x ), Molybdenum boride (MoB x ), molybdenum disilicide (MoSi x ), molybdenum borocarbide (MoB x C y ), and molybdenum carbonitride (MoC x N y The provided precursors can be used to deposit a variety of molybdenum-containing materials, including, but not limited to, molybdenum-containing compounds, such as, but not limited to, molybdenum-containing compounds having a molybdenum content of 100 to 1500 nm, and molybdenum-containing compounds having a molybdenum content of 100 to 150 nm, and molybdenum-containing compounds having a molybdenum content of 100 to 150 nm.

[0042] "Molybdenum metal" or "metallic molybdenum" as used herein refers to a material consisting essentially of molybdenum (Mo). Other elements (e.g., C, N, or O) may be present in molybdenum metal in small amounts (e.g., total content less than about 15 atomic %, or less than about 10% (hydrogen is not included in this calculation)). "High purity molybdenum metal" as used herein refers to molybdenum metal containing less than about 5% other elements, e.g., less than about 1% other elements (hydrogen is not included in this calculation).

[0043] Molybdenum nitride (MoN x ), molybdenum carbide (MoC x ), Molybdenum boride (MoB x), molybdenum disilicide (MoSi x ), molybdenum borocarbide (MoB x C y ), and molybdenum carbonitride (MoC x N y ) is a mixture of molybdenum and nitrogen (MoN x ), Molybdenum and Carbon (MoC x ), molybdenum and boron (MoB x ), molybdenum and silicon (MoSi x ), Molybdenum, Boron and Carbon (MoB x C y ), and Molybdenum, Carbon, and Nitrogen (MoC x N y ), where x and y indicate that the stoichiometry of these compounds may vary. Other elements may be present in these compounds in small amounts (e.g., less than about 10 atomic %) (hydrogen is not included in this calculation).

[0044] The term "semiconductor substrate" as used herein refers to a substrate at any stage of semiconductor device fabrication that includes semiconductor material anywhere within its structure. It is understood that the semiconductor material in a semiconductor substrate need not be exposed. A semiconductor wafer having multiple layers of other materials (e.g., dielectrics) covering the semiconductor material is an example of a semiconductor substrate. The following detailed description assumes that the disclosed embodiments are implemented on a semiconductor wafer, such as on a 200 mm, 300 mm, or 450 mm semiconductor wafer. However, the disclosed embodiments are not so limited. Workpieces may be of various shapes, sizes, and materials. In addition to semiconductor wafers, other workpieces that may utilize the disclosed embodiments include various articles such as printed circuit boards and the like.

[0045] The term "about" when used in reference to a numerical value includes a range of plus or minus 10% of the stated numerical value, unless otherwise specified.

[0046] The term "alkyl" as used herein refers to a saturated substituent containing only carbon and hydrogen atoms. Alkyl includes both linear, branched, and cyclic groups. Examples of linear alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, n-butyl, and the like. Examples of branched alkyl groups include, but are not limited to, isopropyl, isobutyl, sec-butyl, and t-butyl. Examples of cycloalkyl groups include, but are not limited to, cyclopropyl, cyclopentyl, cyclohexyl, and the like.

[0047] The term "fluoroalkyl" as used herein refers to an alkyl group containing one or more fluorine substituents. In some embodiments, the fluoroalkyl contains only fluorine substituents, such as CF3, C2F5, C3F7. The fluoroalkyl may be linear, branched, or cyclic.

[0048] The term "alkylsilyl" as used herein refers to a SiR group, where at least one R is alkyl and each R is independently selected from H and alkyl. Alkylsilyl includes monoalkylsilyl, bisalkylsilyl, and trisalkylsilyl. Examples of alkylsilyl include trimethylsilyl, dimethylsilyl, methylsilyl, triethylsilyl, diethylsilyl, and ethylsilyl.

[0049] The term "alkylamino," as used herein, refers to the group NR, where at least one R is alkyl and each R is independently selected from H and alkyl. Examples of alkylamino substituents include dimethylamino and diethylamino substituents.

[0050] The term "alkoxy" refers to the group OR, where R is alkyl. Examples of alkoxy groups include methoxy, ethoxy, and propoxy groups.

[0051] The term "independently selected," when referring to selection of R substituents in a molecule that contains multiple R groups, means that the selections of R substituents at different atoms of the molecule are independent, and also that the selection of R substituents at an atom that has multiple R substituents is independent.

[0052] Molybdenum metal films have not been widely used in semiconductor processing, at least in part because molybdenum has a high affinity for carbon, nitrogen, and oxygen, making it difficult to obtain molybdenum metal with low impurity contamination levels and therefore low resistivity. Many common molybdenum deposition precursors have low thermal stability, resulting in poor step coverage in high aspect ratio features. Existing organometallic molybdenum precursors with molybdenum-carbon bonds can result in high levels of carbon contamination in the deposited molybdenum, leading to high resistivity. For example, the use of molybdenum carbonyl compounds such as Mo(CO)6 can cause large amounts of carbon (e.g., at least 5 atomic %) to be incorporated into the growing molybdenum metal film, as molybdenum acts as a catalyst for CO dissociation. While molybdenum halides do not suffer from this problem, existing halide-based molybdenum-containing deposition precursors have a number of other undesirable properties. For example, when depositing molybdenum on a substrate containing an exposed fluorine-susceptible layer (e.g., a silicon-containing material such as a silicon oxide-based dielectric), molybdenum hexafluoride (MoF6) requires a fluorine barrier and etch stop layer. Molybdenum pentachloride (MoCl5) is another conventional precursor that has a number of drawbacks, including a high melting point that can induce etching of the growing molybdenum film. Modification of homoleptic halide precursors by exchanging the halide ligands with oxo ligands, such as the molybdenum oxychlorides MoOCl4 and MoO2Cl2, increases volatility, but these precursors are difficult to reduce to pure molybdenum metal due to the strong molybdenum-oxygen double bond. Furthermore, MoCl5, MoOCl4, and MoO2Cl2 are all high-melting corrosive solids that are undesirable for bulk manufacturing.

[0053] The molybdenum precursors and deposition methods provided herein can overcome one or more of these shortcomings. In some embodiments, high purity molybdenum metal films are deposited using the provided precursors and methods, where the deposited high purity molybdenum metal films consist essentially of molybdenum and have less than about 5 atomic % of other elements, such as less than about 3 atomic % of other elements, or less than about 1 atomic % of other elements (hydrogen is not included in this calculation). In some embodiments, molybdenum metal films are provided that have a resistivity of less than about 50 μΩ·cm, such as less than about 30 μΩ·cm, for a film thickness of 100 Å. In some embodiments, especially when fluorine-free precursors are used, molybdenum metal can be deposited directly on a substrate containing exposed fluorine-sensitive materials, without the need to protect the substrate with an etch stop layer. For example, molybdenum metal or other molybdenum-containing films can be deposited on exposed silicon oxide-based dielectrics, silicon-containing dielectrics such as silicon nitride and silicon carbide, or substrates containing amorphous or crystalline silicon or silicon germanium. Silicon oxide-based dielectrics, as used herein, refer to dielectrics that contain silicon-oxygen bonds and include thermally grown silicon oxides, silicates, TEOS (tetraethyl orthosilicate) deposited oxides, and the like.

[0054] The precursors provided herein are selected so that they can be easily reduced to molybdenum metal, and preferably do not contain molybdenum-oxygen double bonds. Furthermore, the precursors are easily vaporized and stable at the target temperature and pressure. For example, in some embodiments, the precursors are used in deposition reactions at temperatures below about 450° C., such as below about 400° C.

[0055] To maintain adequate volatility, in many embodiments described herein, precursors are selected that have a molecular weight of less than about 450 g / mole, such as less than about 400 g / mole.

[0056] Generally, molybdenum precursors can include molybdenum in a wide range of oxidation states from 0 to +6. In some embodiments, molybdenum compounds having molybdenum in the lower oxidation states of +3, +4, and +5 are preferred.

[0057] Halide-Containing Heteroleptic Molybdenum Compounds In one aspect, halide-containing heteroleptic molybdenum compounds (i.e., compounds with different types of ligands) are used as precursors for the deposition of molybdenum-containing films, such as the deposition of molybdenum metal, molybdenum nitride, or molybdenum carbide. In one embodiment, the precursor is a compound that includes molybdenum, at least one halide that forms a bond with the molybdenum, and at least one organic ligand that has any of the elements N, O, and S, any atom of which forms a bond with the molybdenum. Examples of suitable organic ligands that provide nitrogen or oxygen bonds include amidinates, amidates, iminopyrrolidinates, diazadienes, β-iminoamides, α-iminoalkoxides, β-aminoalkoxides, β-diketiminates, β-ketoiminates, β-diketonates, amines, and pyrazolates. Examples of suitable organic ligands that provide sulfur bonds include thioethers, thiolates, dithiolenes, dithiolates, and α-iminothiolenes. These ligands can be substituted or unsubstituted. In some embodiments, these ligands include one or more substituents independently selected from the group consisting of H, alkyl, fluoroalkyl, alkylsilyl, alkylamino, and alkoxy substituents. The organic ligands can be neutral or anionic (e.g., monoanionic or dianionic), and the molybdenum can be in various oxidation states, such as +1, +2, +3, +4, +5, and +6.

[0058] Examples of suitable N- and / or O-containing organic ligand structures 1-17 are shown in FIG. 1, and exemplary suitable S-containing organic ligand structures 18-26 are shown in FIG. 2. wherein each R is independently selected from H, alkyl, fluoroalkyl, alkylsilyl, alkylamino, and alkoxy. In some embodiments, each R is independently selected from H, alkyl, and fluoroalkyl. In some embodiments, each R is independently selected from H, methyl, ethyl, n-propyl, isopropyl, isobutyl, n-butyl, sec-butyl, t-butyl, pentyl, hexyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, cyclopropylethyl, cyclopropylpropyl, cyclobutylmethyl, and cyclobutylethyl. In some embodiments, each R is an independently selected alkyl. In some embodiments, ligands having branched alkyl substituents such as isopropyl and isobutyl are preferred because such ligands provide more volatile molybdenum precursors.

[0059] In some embodiments, at least one organic ligand in the precursor is an amine. Suitable amines include monodentate amines (e.g., monoalkylamines, dialkylamines), bidentate amines (e.g., unsubstituted or N-alkyl substituted ethylenediamines), and higher dentate amines (e.g., substituted or unsubstituted diethylenetriamines). An example of a monodentate amine is amine 1 shown in FIG. 1, where at least one R is alkyl or fluoroalkyl, and each R is independently selected from the group consisting of H, alkyl, and fluoroalkyl. In some embodiments, at least one R is alkyl, and each R is independently selected from H and alkyl. In some embodiments, at least one organic ligand is an amide, such as monoanionic amide 16, where at least one R is alkyl or fluoroalkyl, and each R is independently selected from H, alkyl, and fluoroalkyl. In some embodiments, at least one organic ligand is an imide, such as dianionic imide 17, where R is alkyl or fluoroalkyl. Generally, the imide-containing precursors can be used to deposit a variety of molybdenum-containing films (including molybdenum metal), but in some embodiments, the precursors are more preferred for depositing molybdenum nitrides and molybdenum carbonitrides because they form strong molybdenum-nitrogen bonds and act as a nitrogen source for the resulting films. In some embodiments, at least one organic ligand in the precursor is an amidinate. An example of an amidinate is amidinate 2 shown in FIG. 1, where each R is independently selected from H, alkyl, and fluoroalkyl. Amidinate 2 is a monoanionic ligand that can form two molybdenum-nitrogen bonds and function as a bidentate ligand.

[0060] In some embodiments, at least one organic ligand in the precursor is an amidate. An example of an amidate is amidate 3 shown in Figure 1, where each R is independently selected from H, alkyl, and fluoroalkyl. Amidate 3 is a monoanionic ligand that can form one molybdenum-nitrogen bond and one molybdenum-oxygen bond and function as a bidentate ligand.

[0061] In some embodiments, at least one organic ligand in the precursor is a diazaene. Examples of diazadiene are 1,4-diazabuta-1,3-diene (DAD) 5, 6, and 7, where each R is independently selected from H, alkyl, and fluoroalkyl. An interesting property of this ligand is that it can exist in a neutral form 5, a monoanionic radical form 6, and a dianionic form 7. Complexes of DAD 6 are particularly useful for the deposition of molybdenum metal and high purity molybdenum metal, since the monoanionic (radical) form 6 can be relatively easily removed during deposition due to its redox activity. DAD ligands 5, 6, and 7 function as bidentate ligands and can each form two molybdenum-nitrogen bonds. In some embodiments, the molybdenum precursor comprises DAD ligand 5, 6, or 7 as the organic ligand, where each R is independently selected from methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and t-butyl.

[0062] In some embodiments, the at least one organic precursor is an iminopyrrolidinate (e.g., iminopyrrolidinate 4, where each R is independently selected from H, alkyl, and fluoroalkyl), a β-iminoamide (e.g., β-iminoamide 8, where each R is independently selected from H, alkyl, and fluoroalkyl), an α-iminoalkoxide (e.g., α-iminoalkoxide 9, where each R is independently selected from H, alkyl, and fluoroalkyl), a β-diketiminate (e.g., β-diketiminate 10, where each R is independently selected from H, alkyl, and fluoroalkyl), a β-ketoiminate (e.g., β-keto iminate 11, where each R is independently selected from H, alkyl, and fluoroalkyl), β-diketonate 12 (e.g., β-diketonate 12, where each R is independently selected from H, alkyl, and fluoroalkyl), pyrazolate (e.g., pyrazolate 13, where each R is independently selected from H, alkyl, and fluoroalkyl), β-aminoalkoxide (e.g., β-aminoalkoxide 14, where each R is independently selected from H, alkyl, and fluoroalkyl), or guanidinate 15 (e.g., guanidinate 15, where each R is independently selected from H, alkyl, and fluoroalkyl). These are monoanionic ligands capable of binding to molybdenum in a bidentate manner.

[0063] In some embodiments, at least one organic precursor is a sulfur-containing ligand capable of forming a molybdenum-sulfur bond. In some embodiments, at least one organic ligand in the precursor is a thioether. The term "thioether" as used herein broadly includes both monodentate and polydentate (e.g., bidentate or tridentate) thioethers, as well as ligands containing both thioether and thiolate (or other) moieties. Examples of monodentate thioethers are dialkylsulfides R2S (where each R is an alkyl), such as dimethylsulfide, diethylsulfide, diisobutylsulfide, etc. Examples of polydentate thioether ligands that also have a thiolate moiety include (SCH2CH2SCH2CH2S) 2- An example of a monodentate thioether is thioether 18 shown in FIG. 2, where each R is independently selected from the group consisting of alkyl and fluoroalkyl. In some embodiments, each R is independently selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and t-butyl. In some embodiments, at least one organic ligand is a thiolate, such as a monoanionic thiolate 19, where R is an alkyl or fluoroalkyl. For example, R can be methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, or t-butyl. In some embodiments, the thiolate is a dithiolate, such as a dianionic α-dithiolate 24, where each R is independently selected from H, alkyl, and fluoroalkyl, or a dianionic β-dithiolate 25, where each R is independently selected from H, alkyl, and fluoroalkyl. Dithiolates can form two molybdenum-sulfur bonds with molybdenum.

[0064] In some embodiments, at least one organic ligand in the precursor is a dithiolene. Examples of dithiolene are structures 20, 21, and 22, where each R is independently selected from H, alkyl, and fluoroalkyl. This ligand (similar to DAD) can exist in neutral form 20, monoanionic radical form 21, and dianionic form 22. Complexes of dithiolene 21 are particularly useful for the deposition of molybdenum metal and high purity molybdenum metal, since the monoanionic radical form 21 can be relatively easily removed during deposition and reduction of the molybdenum precursor due to its redox activity. Dithiolene ligands 20, 21, and 22 function as bidentate ligands, each capable of forming two molybdenum-sulfur bonds. In some embodiments, the molybdenum precursor comprises dithiolene ligands 20, 21, and / or 22 as organic ligands, where each R is independently selected from methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, and t-butyl.

[0065] In some embodiments, at least one organic ligand in the precursor is an α-iminothiolene, such as structure 23, where each R is independently selected from H, alkyl, and fluoroalkyl. In some embodiments, each R substituent at the carbon atom is independently selected from H, alkyl, fluoroalkyl, alkylsilyl, alkylamino, and alkoxy substituents, while the R substituent at the nitrogen is independently selected from alkyl and fluoroalkyl. In some embodiments, the R substituent at the nitrogen is independently selected from methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, and t-butyl. This ligand (similar to DAD and dithiolene) has a monoanionic radical form as shown in structure 23, is redox active, and is easily removable during the reduction process.

[0066] In some embodiments, the molybdenum-containing precursor preferably does not contain a molybdenum-oxygen or molybdenum-nitrogen double bond. In some embodiments, the molybdenum compound does not simultaneously contain an imido ligand and a guanidinate ligand. In some embodiments, the molybdenum compound does not contain an imido ligand or a guanidinate ligand. In some embodiments, the molybdenum compound does not contain a CO, alkyl, or cyclopentadienyl ligand.

[0067] In some embodiments, the precursor has the formula Mo(X) m (L) n where m is 1-4, n is 1-3, each X is independently a halide selected from F, Cl, Br, and I, and each L is an organic ligand as described above, such as a ligand independently selected from amidinates, amidates, iminopyrrolidinates, diazadiene, β-iminoamides, α-iminoalkoxides, β-aminoalkoxides, β-diketiminates, β-ketoiminates, β-diketonates, amines, and pyrazolates, thioethers, thiolates, dithiolenes, dithiolates, and α-iminothiolenes. In some embodiments, in the named ligands, each R is independently selected from H, alkyl, and fluoroalkyl.

[0068] In some embodiments, L is a bidentate ligand. Examples of suitable precursors of formula Mo(L)Cl4 that utilize a bidentate ligand are shown in Figure 3. These are Mo(V) compounds including amidinate molybdenum complexes 27, DAD complexes 28, β-diketiminate complexes 29, pyrazolate complexes 30, amidate complexes 31, β-iminoamide complexes 32, β-ketoiminate complexes 33, β-aminoalkoxide complexes 34, iminopyrrolidinate complexes 35, α-iminoalkoxide complexes 36, and β-diketonate complexes 37.

[0069] Heteroleptic complexes having molybdenum-halide bonds and organic ligands as described herein can be synthesized using the reaction of a molybdenum halide starting material with a compound containing an organic ligand in neutral or anionic form. For example, a molybdenum(V) precursor can be prepared using MoCl5 as a starting material. A Mo(III) precursor can be prepared using MoX3(THF)3 as a starting material, where X is selected from chloride, bromide, and iodide, and THF is tetrahydrofuran. The starting material can be treated with a neutral or anionic form of the ligand (e.g., a salt such as a lithium or sodium salt) to form a heteroleptic complex as described herein. An example of a reaction that can be used to prepare such a complex is shown in Figure 4. Equation 1 illustrates the preparation of amidinato-tetrachloromolybdenum(V) using the reaction of molybdenum pentachloride with lithium amidinate. Equation 2 illustrates the preparation of bis-amidinato-trichloromolybdenum(V) using the reaction of molybdenum pentachloride with two equivalents of lithium amidinate. The stoichiometry of the molybdenum precursor (the number of halide and organic ligands in the resulting precursor) can be controlled by controlling the stoichiometric ratio of the starting materials.

[0070] The reaction may be carried out in a variety of aprotic solvents. For example, the reaction may be carried out in an ether solvent (such as tetrahydrofuran, 2-methyltetrahydrofuran, diethyl ether, methyl-tert-butyl ether, 1,2-dimethoxyethane, etc.), a hydrocarbon solvent (such as toluene, benzene, heptane, hexane, pentane, etc.), or a halocarbon solvent (such as chlorobenzene, dichlorobenzene, fluorobenzene, difluorobenzene, dichloromethane, chloroform, etc.). The reaction may be carried out at a wide range of temperatures, depending on the boiling point of the solvent and the solubility of the product. In some embodiments, the starting materials, reaction intermediates, and desired products are unstable to moisture and oxygen. Therefore, the reaction process should be carried out using anhydrous and air-free conditions using a protective inert gas such as nitrogen or argon.

[0071] The heteroleptic molybdenum compounds containing molybdenum-halide bonds and organic ligands described herein can advantageously provide high purity molybdenum metal in CVD and ALD depositions. Furthermore, the use of these compounds can be accompanied by reduced etching of substrate materials compared to conventional homoleptic molybdenum halides. These advantages are provided for illustrative purposes and are not intended to limit the use of these compounds to only molybdenum metal deposition or deposition on etch-sensitive substrates.

[0072] In some embodiments, when deposition is performed on fluorine sensitive materials (e.g., silicon-containing materials), the precursors are selected to be fluorine-free, for example, to include any of Cl, Br, and I as halides in the complex. Additionally, in these embodiments, the use of compounds with fluoroalkyl substituents may be avoided.

[0073] Sulfur-containing molybdenum compounds In one aspect, the sulfur-containing molybdenum compound is used as a precursor for the deposition of a molybdenum-containing film, for example, for the deposition of molybdenum metal, molybdenum sulfide, molybdenum nitride, or molybdenum carbide. In some embodiments, the molybdenum compound comprises molybdenum and at least one sulfur-containing ligand that provides a molybdenum-sulfur bond. Because sulfur impurities are easier to remove compared to oxygen, carbon, and nitrogen impurities, molybdenum precursors based on sulfur-containing ligands can be used to deposit molybdenum-containing films that are substantially free of impurities. In some embodiments, the molybdenum compound does not comprise a molybdenum-carbon bond and / or does not comprise a molybdenum-oxygen double bond. In some embodiments, the molybdenum compound does not comprise a molybdenum-nitrogen double bond. In some embodiments, in the provided molybdenum precursor, molybdenum forms bonds only with sulfur atoms.

[0074] Examples of suitable sulfur-containing ligands that provide sulfur bonds include thioethers, thiolates, dithiolenes, dithiolates, thiocarbamates, and α-iminothiolenes. The ligands can include one or more substituents independently selected from the group consisting of H, alkyl, fluoroalkyl, alkylsilyl, alkylamino, and alkoxy substituents. The ligands can be neutral or anionic (e.g., monoanionic or dianionic), and the molybdenum can be in various oxidation states, such as 0, +1, +2, +3, +4, +5, and +6.

[0075] In some embodiments, the sulfur-containing ligand is Ligand 18-25 shown in FIG. 2, where the R substituents are as described above. Examples of suitable molybdenum precursors include molybdenum thiolates, Mo(SR)4, where R is alkyl (e.g., methyl, ethylpropyl, butyl). In one specific example, the precursor is tetrakis(tert-butylthiolato)molybdenum(IV):Mo(SR)4, where R is t-butyl. Another example of a suitable molybdenum precursor is a molybdenum thiocarbamate, such as tetrakis(diethyldithiocarbamate)molybdenum(IV): [ka]

[0076] where each R is independently selected from alkyl (e.g., ethyl, methyl, propyl, butyl), and fluoroalkyl (e.g., CF3). In one specific example, the precursor is tetrakis(diethyldithiocarbamato)molybdenum(IV).

[0077] In some embodiments, dithiolene complexes of molybdenum are provided, where the dithiolene is in neutral form 20, anion radical form 21, and dianionic form 22, where each R is independently H, alkyl, or fluoroalkyl. The dithiolene complexes are redox active and can support molybdenum in various oxidation states. The redox reactions of dithiolene ligands 20, 21, and 22 are shown in Equation 3. [ka]

[0078] In one embodiment, the precursor is Mo(21)3, where each R in 21 is independently selected from H, alkyl, and fluoroalkyl. For example, R can be methyl, ethyl, CF3, etc. This is a homoleptic Mo(III) compound that contains only molybdenum-sulfur bonds.

[0079] In some embodiments, the ligand may provide a nitrogen bond in addition to the sulfur bond. One example of such a ligand is α-iminothiolene 23, a redox active radical anion ligand that may behave similarly to thiolene. In some embodiments, the precursor is the Mo(III) compound Mo(23)3, where each R in compound 23 is independently selected from H, alkyl, and fluoroalkyl.

[0080] In some embodiments, the precursor is MoL n The compound is represented by the formula: where n is 2-6, and L is a sulfur-containing ligand, such as any of the sulfur-containing ligands described herein. In some embodiments, each L is the same sulfur-containing ligand. In other embodiments, the precursor may include different sulfur-containing ligands L. Examples of precursors include Mo(19)2, Mo(19)3, Mo(19)4, Mo(19)5, Mo(19)6, Mo(19)2(18)2, Mo(19)3(18), Mo(19)4(18)2, Mo(21)3, Mo(20)(21)2, Mo(22) 3、Examples of sulfur-containing molybdenum compounds described herein include Mo(21)(22)2, Mo(20)(22)2, Mo(23)3, Mo(24)3, and Mo(25)3. The sulfur-containing molybdenum compounds described herein can be synthesized using the reaction of a molybdenum halide starting material with a compound containing an organic sulfur-containing ligand in neutral or anionic form. For example, a molybdenum(V) precursor can be prepared using MoCl5 as a starting material. Mo(III) or Mo(IV) precursors can be prepared using the corresponding halide or MoX3(L)3 or MoX4(L)2 as starting materials, where X is selected from chloride, bromide, and iodide, and L is a neutral Lewis base such as tetrahydrofuran or diethyl ether. The starting material can be treated with the desired sulfur-containing ligand in neutral or anionic form (e.g., a salt such as a lithium or sodium salt) to form the sulfur-containing complexes described herein.

[0081] In one example, Mo(IV) thiolate complexes are prepared by reacting molybdenum tetrachloride with lithium thiolate. For example, MoCl4 can be reacted with t-BuSLi in 1,2-dimethoxythane solvent to form the Mo(t-BuS)4 compound.

[0082] The α-iminothiolene ligands can be formed from the corresponding α-imino ketones by thionation with a suitable reagent, such as Lawesson's reagent. The radical anionic forms of the α-iminothiolenes can then be prepared by treatment with an alkali metal, such as lithium. The resulting ligands and ligand salts can be reacted with molybdenum halides to form the α-iminothiolene-containing molybdenum compounds.

[0083] Molybdenum complexes can also be prepared using zero-valent starting materials, such as molybdenum hexacarbonyl. The starting materials can be treated with neutral ligands, such as thioethers (dialkylsulfides), to induce redox-neutral ligand exchange. The zero-valent starting materials can also be treated with ligand precursors, such as bis(diethylthiocarbamoyl)disulfide or bis(trifluoromethyl)-1,2-dithiete, to induce oxidative addition to form the sulfur-containing complexes described herein.

[0084] The reaction may be carried out in a variety of aprotic solvents. For example, the reaction may be carried out in an ether solvent (such as tetrahydrofuran, 2-methyltetrahydrofuran, diethyl ether, methyl-tert-butyl ether, 1,2-dimethoxyethane, etc.), a hydrocarbon solvent (such as toluene, benzene, heptane, hexane, pentane, etc.), or a halocarbon solvent (such as chlorobenzene, dichlorobenzene, fluorobenzene, difluorobenzene, dichloromethane, chloroform, etc.). The reaction may be carried out at a wide range of temperatures, depending on the boiling point of the solvent and the solubility of the product. In some embodiments, the starting materials, reaction intermediates, and desired products are unstable to moisture and oxygen. Therefore, the reaction process should be carried out using anhydrous and air-free conditions using a protective inert gas such as nitrogen or argon.

[0085] 1,4-Diazabutadiene (DAD)-containing precursors In another aspect, DAD-containing molybdenum precursors are provided. DAD can be bound to molybdenum in its neutral form 5, radical-anionic form 6, and dianionic form 7. In some embodiments, homoleptic DAD complexes of formula Mo(DAD)m are provided, where m is 1-3 and each DAD is independently selected from neutral DAD5, radical-anionic DAD6, and dianionic DAD7. The oxidation state of molybdenum in these complexes can range from 0 to +6. Non-limiting examples of suitable homoleptic DAD complexes include tris-DAD Mo(III) precursor Mo(6)3, bis-DAD Mo(IV) precursor(7)2, bis-DAD Mo(III) precursor Mo(6)(7), and bis-DAD Mo(II) precursor Mo(6)2.

[0086] In some embodiments, homoleptic DAD complexes (i.e., compounds with identical ligands) are prepared using the reaction between a molybdenum halide in the required electronic configuration and a source of the DAD ligand. For example, the tris-DAD Mo(III) precursor Mo(6)3 can be synthesized by reacting MoCl3 with three equivalents of the radical anion derived from the DAD ligand, and can be prepared from the neutral form of the DAD ligand by treatment with an alkali metal (e.g., lithium) in a solvent (e.g., THF) as shown in Equation 4.

[0087] [ka]

[0088] In some embodiments, heteroleptic DAD-containing molybdenum compounds are provided. In some implementations, the precursor comprises molybdenum, at least one DAD ligand bound to the molybdenum, and at least one second ligand, where the DAD can be a neutral DAD6, a radical anionic DAD7, or a dianionic DAD8, and the second ligand is independently selected from an anionic ligand and a neutral ligand. In some embodiments, the precursor does not contain a CO ligand as the only second ligand. In some embodiments, the precursor comprises Mo(DAD) m (L) n (X) p where L is a neutral Lewis base ligand and each L is independently selected from CO, amine, phosphine, thioether, nitrile, and isonitrile, and X is an anionic ligand and each X is independently selected from halide, alkyl, allyl, and cyclopentadienyl, m is 1-3, n is 0-4, and p is 0-4. Nitriles are RCN compounds where R is an alkyl. Isonitriles are RNC compounds where R is an alkyl. Other suitable anionic ligands include alkoxides, amides, imides, and any other anionic ligand containing a donor atom selected from C, N, O, B, S, Si, Al, and P.

[0089] Heteroleptic DAD-containing precursors include, but are not limited to, Mo(7)2(RCN)Cl, Mo(7)2(RNC)Cl, Mo(8)(CO), Mo(6)(13)Cl, Mo(6)(18)Cl, Mo(6)2Cl, Mo(6)2(14), Mo(6)2(19), Mo(6)2(24).

[0090] Heteroleptic DAD-containing precursors can be prepared by sequential salt metathesis reactions in one pot or using multiple steps. Molybdenum halide starting materials, such as Mo(V), Mo(IV), or Mo(III) halides, can be treated with the anionic form of the DAD ligand or other anionic ligands. The neutral Lewis base ligands can be exchanged using thermal treatment or photoexcitation.

[0091] Heteroleptic DAD-containing precursors can also be prepared using zero-valent molybdenum starting materials, such as molybdenum hexacarbonyl, which can undergo oxidative addition with redox-active ligands, such as DAD ligands.

[0092] In some embodiments, precursors containing radical anionic DAD ligands 8 are particularly preferred for the deposition of molybdenum metal and high purity molybdenum metal. In the radical anionic form 7, the DAD ligands are believed to function as electron sources that electronically couple to vacant molybdenum d orbitals and reduce the molybdenum ion to the zero-valent metallic state. After electron transfer from the ligand to the metal, the volatile neutral DAD ligands 6 can be purged away from the molybdenum metal growth surface. Because the DAD ligands can be removed intact from the growth surface, the incorporation of impurity elements such as C and N is reduced when using DAD precursors compared to other metal organic precursors. Thus, molybdenum precursors containing radical anionic DAD ligands can be used to deposit high purity molybdenum metal at low temperatures.

[0093] Dimolybdenum Precursor In another embodiment, precursors for the deposition of molybdenum-containing coatings are dimolybdenum compounds that contain a molybdenum-molybdenum bond (e.g., a double bond or multiple molybdenum-molybdenum bonds, such as any multiple bond of bond order from 2 to 5). Such precursors are particularly useful for the deposition of molybdenum metal and high purity molybdenum metal because such compounds are easier to reduce to metallic molybdenum than many mononuclear molybdenum compounds.

[0094] In some embodiments, a precursor for deposition of a molybdenum-containing film is provided, the precursor comprising Mo2L n wherein each L is independently selected from amidate, amidinate, and guanidinate ligands, n is 2-5, and the precursor comprises a plurality of molybdenum-molybdenum bonds. In some embodiments, each L is independently selected from amidinate ligand 2, amidate ligand 3, and guanidinate ligand 15, and wherein each R in the amidinate, amidate, and guanidinate is independently selected from H, alkyl, fluoroalkyl, alkylsilyl, alkylamino, and alkoxy substituents. In some embodiments, each R is independently selected from H, alkyl, and fluoroalkyl. In some embodiments, each L is an amidinate, and the precursor has the formula Mo2(L)3 or Mo2(L)4. In some embodiments, each L is an amidinate, and the precursor has the formula Mo2(L)3 or Mo2(L)4. In some embodiments, each L is a guanidinate and the precursor has the formula Mo2(L)3 or Mo2(L)4. In these complexes, molybdenum has the low oxidation states 2+ (Mo2(L)3) and 3+ (Mo2(L)4), making these complexes particularly suitable for facile reduction to molybdenum metal. One exemplary structure of an amidate paddlewheel type di-Mo(II) precursor with quadruple molybdenum-molybdenum bonds is shown in Structure 38: [ka]

[0095] In some embodiments, each of R and R' is independently selected from alkyl (e.g., methyl, ethyl, isopropyl, and t-butyl). In some embodiments, 1, 2, 3, or 4 of the 38 amidate ligands may be replaced with an amidinate ligand or a guanidinate ligand.

[0096] The dimolybdenum 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 is provided that contains any of the precursors described herein in solid or liquid form. In another aspect, a solution of any of these precursors is provided, the solvent of which may include, for example, a high boiling point hydrocarbon solvent such as a higher alkane. In some embodiments, the container that holds 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 exposure of the precursor to air and possible decomposition due to exposure to 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, the inlet adapted to connect to a source of carrier gas that can flow over or through the precursor, thereby assisting in the vaporization of the precursor. The outlet is adapted to remove the carrier gas and precursor vapor from the container and is configured to connect to a conduit that can be used to deliver the precursor vapor to a process chamber. The inlet and outlet each have a closed position and an open position, and may include, for example, a manual valve that can be used to switch from the closed position to the open position and back. When the container is stored or transported, the inlet and outlet are closed. When the container is installed in a deposition apparatus for use, the inlet and outlet valves may be opened, and carrier gas may flow in through the inlet and out through the outlet to carry the precursor vapor. In some embodiments, the container has a flow-over design, with the inlet and outlet positioned above the precursor surface. For example, in a cylindrical container, the inlet and outlet may be positioned at approximately the same vertical height (e.g., the vertical distance between the inlet and outlet may be less than about 20% of the height of the cylinder). In other embodiments, the container has a bubbler design, with the inlet positioned below the precursor surface and the outlet positioned above the inlet (e.g., above the precursor surface). For example, in a cylindrical vessel, the inlet and outlet may be positioned vertically spaced apart from one another (e.g., the vertical distance between the inlet and outlet may be greater than about 30% of the cylinder height, e.g., greater than about 50%, or greater than about 80%).

[0097] Deposition of Molybdenum-Containing Materials Molybdenum-containing materials can be deposited by various deposition techniques, such as CVD (including thermal CVD and PECVD) and ALD (including thermal ALD and PEALD) using the precursors described herein. An exemplary method is illustrated by the process flow diagram shown in FIG. 4A. The process begins in 401 by introducing a molybdenum precursor described herein into a process chamber containing a semiconductor substrate. The precursor may be introduced in vaporized form in a flow of an inert gas, such as argon, helium, or nitrogen (N2). In operation 403 (which may occur before, after, or during the introduction of the molybdenum-containing precursor 401), a second reactant is introduced into the process chamber containing the substrate. In some embodiments, the introduction of the molybdenum precursor and the introduction of the second reactant are sequential. The chemical nature of the second reactant depends on the chemical nature of the target molybdenum-containing film. For example, in the case of deposition of molybdenum metal, the second reactant is typically a reducing reactant (including a reactant that forms a reducing environment when activated in a plasma). Examples of reactants suitable for forming molybdenum metal include hydrogen (H2), ammonia (NH3), hydrazine (N2H4), amines, diborane (B2H6), silane (SiH4), disilane (Si2H6), alcohols, hydrogen sulfide (H2S), or thiols. In some embodiments, H2 is the preferred reducing reactant for depositing molybdenum metal. In some embodiments, the molybdenum-containing precursor reacts sequentially with several reactants. For example, in some embodiments, molybdenum metal is deposited by adsorbing a layer of a molybdenum-containing precursor on a substrate, reacting it with a second reactant, and then reacting it with a third reactant. In one embodiment, the molybdenum-containing precursor (first reactant) is first reacted with at least one of water, H2S, and a thiol (second reactant). The substrate containing the reacted precursor is then treated with hydrogen (H2) (third reactant). In some embodiments, after each of the reactants is introduced, the process chamber is purged and / or evacuated.In some embodiments, the first reactant (e.g., water, HS, or a thiol) is selected to facilitate removal of ligands from the molybdenum precursor, while the third reactant (e.g., H) is selected to remove remnants of the ligands (e.g., C, N, S, O-containing impurities) from the surface of the substrate and / or reduce molybdenum to the zero oxidation state to form high purity molybdenum metal.

[0098] When a molybdenum-containing film other than molybdenum metal is deposited, the second reactant can be selected so that it serves as a source of the necessary elements of the molybdenum-containing film, although in some embodiments, these elements may be provided only by the ligand. The process conditions (e.g., temperature, pressure, reactant flow rates, and optionally plasma power) can be adjusted to favor a particular film chemistry. For example, borane and silane reactants can be used to deposit molybdenum boride or molybdenum silicide-containing materials, whereas in some embodiments, these reactants may be used alone or in combination with other reactants (e.g., H2) under different conditions to produce molybdenum metal. For the deposition of molybdenum nitride, a nitrogen-containing second reactant may be selected in some embodiments, and the process conditions can be adjusted to allow the inclusion of nitrogen in the film. For example, NH3, N2H4, N2, alkylamines, and alkylhydrazines may be used as second reactants for the deposition of molybdenum nitride. For the deposition of molybdenum carbide, a carbon-containing second reactant may be used and the process conditions may be adjusted to allow for the inclusion of carbon in the film. For example, a hydrocarbon may be introduced as the second reactant to form molybdenum carbide. Molybdenum carbonitride films may be formed by introducing a nitrogen-containing reactant and / or a carbon-containing reactant. In some embodiments, the nitrogen-containing and carbon-containing ligands of the molybdenum precursor may function as a source of nitrogen and / or carbon. Molybdenum oxide films may be formed by introducing an oxygen-containing second reactant, such as O2, O3, N2O, CO2, etc. The second reactant may be introduced into the process chamber in a mixture with an inert carrier gas, such as N2, argon, or helium. Molybdenum sulfide films may be deposited using a sulfur-containing reactant or by adjusting the process conditions to allow the inclusion of sulfur from the sulfur-containing molybdenum precursor in the film. Sulfur-containing reactants include H2S, dialkyl sulfides, dialkyl disulfides, and thiols, such as methanethiol, tert-butylthiol.

[0099] In some embodiments, the precursor and the second reactant are mixed in the body of the process chamber. In other embodiments, after the molybdenum precursor is introduced and adsorbed on the surface of the substrate, the process chamber is purged and / or evacuated with an inert gas to remove unadsorbed precursor from the process chamber. In some embodiments, the layer of precursor on the substrate is an adsorption-limited layer. In other embodiments, a thicker layer of molybdenum precursor may form on the surface of the substrate before purging and / or evacuating the process chamber. It should be noted that when the precursor and the second reactant are introduced sequentially, the order of introduction of the precursor and the second reactant may be reversed. In some embodiments, the second reactant is introduced first and adsorbed on the surface of the substrate. The process chamber is then purged and / or evacuated to remove the second reactant from the process chamber.

[0100] Referring to operation 405, the molybdenum precursor reacts with a second reactant to form a layer of molybdenum-containing material on the substrate, the reaction occurring on the surface of the substrate and / or in the body of the process chamber, and optionally plasma-assisted. For example, in a CVD process, the precursor may react with the second reactant in the process chamber. The reaction may be carried out thermally or with plasma activation. In an ALD process, the reaction occurs only at the surface and is limited by the amount of material adsorbed on the surface (by the amount of molybdenum precursor and / or by the amount of adsorbed second reactant). In surface-limited reactions (e.g., ALD), plasma activation is also possible. For example, a layer of adsorbed molybdenum precursor may react with a plasma generated in a gas containing a hydrogen-containing second reactant (e.g., H2, NH3, CO, alcohol, etc.) to form a molybdenum metal layer. Generally, the plasma may be generated directly in the process chamber containing the substrate (direct plasma) or may be generated remotely in another compartment and the resulting plasma activated species provided to the process chamber (remote plasma). The temperature during the reaction process may be, for example, about 20-600° C. Low temperature deposition at about 450° C. or less, such as about 400° C. or less, for example about 100-400° C., is performed in some embodiments and is particularly advantageous for the deposition of molybdenum metal. The pressure in the process chamber may be about 0.1-100 Torr, for example about 0.5-5 Torr for PEALD processes and 1-60 Torr for thermal ALD processes.

[0101] After the reaction is complete, the formed molybdenum-containing layer can optionally be annealed, as shown in operation 407. The annealing can be performed by increasing the temperature. For example, if the reaction is performed at a relatively low temperature, e.g., less than about 450°C, less than about 400°C, etc., the temperature can be increased by 50-200°C during the annealing. In some embodiments, the annealing is performed at a temperature of about 300-500°C.

[0102] An example of a surface-based deposition process for forming a molybdenum metal film is described in the process flow diagram shown in FIG. 4B. In operation 411, a layer of a molybdenum precursor and / or a layer of a reducible reactant are formed on the surface of the substrate. In some embodiments, the layer is an adsorption-limited layer. Next, in operation 413, the process chamber is purged and / or evacuated. This step ensures that the molybdenum precursor and / or the reducible reactant are only on the surface of the substrate and not within the process chamber. Next, in 415, the molybdenum precursor is reacted with the reducible reactant on the surface of the substrate, optionally using plasma activation. For example, if only the molybdenum precursor is adsorbed on the substrate surface in 411, a reducing reagent is introduced into the process chamber to react with the molybdenum precursor on the surface. If both the molybdenum precursor layer and the reducible reactant layer are formed on the substrate surface in 411, the reaction can be activated in 413 (e.g., using plasma treatment of the surface or an increase in temperature). The process chamber is then purged and / or evacuated at 417, and operations 411-417 are repeated at 419 to form more molybdenum metal. In some embodiments, each cycle of operations 411-417 deposits an average of about 0.1-5.0 Å of molybdenum metal. In some embodiments, 2-100 cycles are performed. For example, 2-20 cycles can be performed. Molybdenum layers having thicknesses of about 5-5,000 Å, for example 5-500 Å, can be formed with a high level of control over the layer thickness. This method can be used to form conformal layers of molybdenum metal with excellent step coverage.

[0103] Molybdenum-containing films can be deposited on a variety of surfaces, such as metals (e.g., copper, nickel, cobalt, tungsten, etc.), dielectrics (e.g., silicon oxide-based dielectrics, silicon nitride, silicon carbide, metal oxides, metal nitrides, etc.), and amorphous and crystalline silicon. In some embodiments, the molybdenum-containing film (e.g., molybdenum metal) is deposited on a substrate containing an exposed dielectric layer and an exposed metal layer.

[0104] In some embodiments, the molybdenum-containing coating is selectively deposited on a dielectric in the presence of exposed metal, and in other embodiments, on a metal in the presence of exposed dielectric. As used herein, "selective deposition" refers to deposition on a target surface at a rate higher than deposition on non-target surfaces. In some embodiments, the selectivity (ratio of deposition rate on a target surface to deposition rate on non-target surfaces) is greater than 2, such as greater than 5. In some embodiments, the molybdenum-containing coating is deposited on a dielectric (e.g., a silicon oxide-based dielectric) without substantial deposition on exposed metal surfaces.

[0105] Selectivity of deposition onto dielectrics in the presence of metals can be achieved by using molybdenum precursors containing ligands that are effective proton acceptors. For example, ligands containing basic deprotonated nitrogen atoms can be protonated with Si-OH groups on the substrate surface, resulting in preferential deposition onto silicon oxide-based dielectrics. Examples of these ligands include amidinates, amidates, iminopyrrolidinates, β-iminoamides, α-iminoalkoxides, β-aminoalkoxides, β-diketiminates, β-ketoiminates, β-diketonates, and pyrazolates. The reaction of a molybdenum amidinate precursor with a dielectric surface containing a Si-OH moiety is shown in Figure 5.

[0106] Selectivity of deposition on metals in the presence of dielectrics can be achieved by the use of redox non-innocent ligands that can function as electron acceptors. Such ligands include radical anion DAD ligand 6, radical anion dithiolene 21, and α-iminothiolene 23. In some embodiments, molybdenum-containing films are selectively deposited on metal surfaces in the presence of exposed dielectrics by reacting a molybdenum-containing precursor containing a compound of molybdenum with dithiolene 21 radical anion ligand and / or α-iminothiolene 23 radical anion ligand to form a molybdenum-containing layer. The R groups in 21 and 23 can be any of the groups described above. In some embodiments, each R is independently selected from H, alkyl, and fluoroalkyl. Molybdenum-containing films can be deposited for a variety of applications in semiconductor processing. In some embodiments, a molybdenum-containing film (e.g., molybdenum metal) is deposited as a conformal layer about 0.1-10 nm thick on a substrate having one or more concave or convex features. In some embodiments, the concave features are filled with a molybdenum-containing material (e.g., molybdenum metal). A cross-sectional schematic of one exemplary substrate is shown in FIG. 6A. The figure shows a substrate 601 having a concave feature 603. Generally, the substrate 601 may include a variety of materials, such as dielectrics, metals, metal nitrides, etc. A conformal layer of molybdenum-containing material 605 is deposited on the substrate 601 using methods and precursors described herein (e.g., using ALD). The resulting structure is shown in FIG. 6B. In some applications, the process continues and the concave features 603 are filled with a molybdenum-containing material 605 (e.g., molybdenum metal), as shown in FIG. 6C. In some embodiments, a molybdenum-containing film is deposited in a recessed feature using a series of ALD cycles to deposit a conformal film multiple times, as shown in Figures 6A-6C. In other embodiments, the recessed feature may be filled using bottom-up film growth.

[0107] The molybdenum-containing films provided herein, and in particular the high purity molybdenum metal, can be used in interconnect metallization (e.g., to fill recessed features to form contacts), logic gate applications in FinFETs, and as an adhesion layer or diffusion barrier, and in 3D NAND manufacturing. Examples of applications include logic and memory contact filling, DRAM embedded wordline filling, vertically integrated memory gates and wordline filling, and 3D integration with through silicon vias (TSVs). The resistivity of molybdenum scales better than that of tungsten, and in some embodiments, molybdenum is a particularly advantageous metal for filling narrow recessed features, e.g., features less than about 20 nm wide. In one exemplary application, molybdenum metal is used to manufacture barrierless contacts. In this application, molybdenum metal is deposited directly into a recessed feature (contact hole) having a width of about 5-100 nm, e.g., about 5-20 nm, formed in a dielectric layer and including exposed dielectric (e.g., silicon oxide, silicon nitride) or low-k material (e.g., silicon oxycarbide) on the sidewalls and exposed silicon or silicon germanium at the bottom. In an alternative embodiment, 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.

[0108] Device The deposition methods described herein can be carried out in a variety of apparatus. A suitable apparatus includes a process chamber having one or more inlets for introducing reactants, a substrate holder disposed within the process chamber and configured to hold the substrate in place during deposition, and optionally a plasma generating mechanism configured to generate a plasma with the process gas. The apparatus may include a controller having program instructions for initiating any of the method steps described herein. The deposition methods described herein may be carried out in corresponding ALD and CVD apparatus available from Lam Research, Inc., Fremont, Calif., such as Altus®, Vector®, and Striker® tools.

[0109] For example, in some embodiments, the apparatus includes a controller having program instructions including the following instructions: instructions for causing introduction of a molybdenum-containing precursor into the process chamber, where the precursor is any of the precursors described herein; and instructions for causing a reaction between the molybdenum precursor and a second reactant to form a layer of molybdenum-containing material on the substrate. The controller may include program instructions for causing any of the methods described herein.

[0110] An example of a deposition apparatus suitable for depositing molybdenum-containing films using the provided methods is shown in FIG. 7. FIG. 7 illustrates generally one embodiment of a process station 700 that may be used to deposit materials using atomic layer deposition (ALD) and / or chemical vapor deposition (CVD), where either ALD or CVD may be plasma-assisted. For simplicity, the process station 700 is illustrated as a stand-alone process station having a process chamber body 702 for maintaining a low pressure environment. However, it will be appreciated that multiple process stations 700 may be included in a common process tool environment. Additionally, it will be appreciated that in some embodiments, one or more hardware parameters of the process station 700 (including those described in more detail below) may be programmatically adjusted by one or more computer controllers.

[0111] The process station 700 is in fluid communication with a reactant delivery system 701 for supplying process gases to a distribution showerhead 706. The reactant delivery system 701 includes a mixing vessel 704 for blending and / or conditioning the process gases delivered to the showerhead 706. One or more mixing vessel inlet valves 720 may control the introduction of process gases to the mixing vessel 704. Similarly, a showerhead inlet valve 705 may control the introduction of process gases to the showerhead 706.

[0112] Some molybdenum-containing precursors may be stored in solid or liquid form before being vaporized and delivered to the process station. For example, the embodiment of FIG. 7 includes a vaporization point 703 for vaporizing solid reactants delivered to a mixing vessel 704. In some embodiments, the vaporization point 703 may be a heated vaporizer. In some embodiments, a flow of inert gas is passed through the heated solid molybdenum precursor or bubbled through the heated liquid molybdenum precursor to carry the precursor vapor to the process chamber at sub-atmospheric pressure. Precursor vapors generated from such vaporizers may condense in downstream supply piping. Small particles may form when incompatible gases are exposed to the condensed reactants. These small particles may clog piping, interfere with the operation of valves, contaminate the substrate, etc. Some approaches to address these issues involve sweeping and / or evacuating the supply piping to remove residual reactants. However, sweeping the supply piping may increase the cycle time of the process station and reduce the throughput of the process station. Thus, in some embodiments, the supply piping downstream of vaporization point 703 may be heat traced. In some examples, mixing vessel 704 may also be heat traced. In one non-limiting example, the piping downstream of vaporization point 703 has a ramped temperature profile ranging from about 100° C. to about 200° C. at mixing vessel 704.

[0113] The showerhead 706 distributes process gases toward the substrate 712. In the embodiment depicted in FIG. 7, the substrate 712 is shown positioned below the showerhead 706 and resting on a pedestal 708. It will be appreciated that the showerhead 706 may have any suitable shape and may have any suitable number and arrangement of ports for distributing process gases to the substrate 712. Although not explicitly shown, in some embodiments, the showerhead 706 is a dual plenum showerhead having at least two conduits, a first type of conduit dedicated to the delivery of a molybdenum-containing precursor vapor and a second type of conduit dedicated to the delivery of a second (or other) reactant. In these embodiments, the molybdenum-containing precursor and reactants are not mixed in the conduits prior to entering the process chamber and do not share conduits when delivered to the chamber sequentially.

[0114] In some embodiments, a microvolume 707 is located under the showerhead 706. By performing ALD and / or CVD processes in a microvolume rather than in the entire volume of the process station, it is possible to reduce reactant exposure and sweep times, reduce the time to change process conditions (e.g., pressure, temperature, etc.), limit exposure of the process station robot to process gases, etc. Exemplary microvolume sizes include, but are not limited to, volumes between 0.1 liters and 2 liters. This microvolume also impacts productivity throughput. While the deposition rate per cycle is reduced, the cycle time is simultaneously reduced. In certain cases, the latter effect is large enough to improve the overall throughput of the module for a given target thickness of the coating.

[0115] In some embodiments, the pedestal 708 may be raised or lowered to expose the substrate 712 to the microvolume 707 and / or to change the volume of the microvolume 707. For example, during a substrate transfer phase, the pedestal 708 may be lowered to allow the substrate 712 to be placed on the pedestal 708. During a deposition process phase, the pedestal 708 may be raised to position the substrate 712 within the microvolume 707. In some embodiments, the microvolume 707 may completely surround the substrate 712 and a portion of the pedestal 708, creating a region of high flow impedance during the deposition process.

[0116] Optionally, the pedestal 708 may be lowered and / or raised during portions of the deposition process to adjust the process pressure, reactant concentration, etc., within the micro-volume 707. In one scenario in which the process chamber body 702 maintains a base pressure during the deposition process, the pedestal 708 may be lowered to evacuate the micro-volume 707. Example ratios of the micro-volume to the process chamber volume include, but are not limited to, volume ratios of 1:700 to 1:10. It will be appreciated that in some embodiments, the height of the pedestal may be programmatically adjusted by a suitable computer controller.

[0117] Although a height adjustable pedestal is mentioned as an example of the deformation of the micro-volume described herein, it will be appreciated that in some embodiments, the position of the showerhead 706 may be adjusted relative to the pedestal 708 to change the volume of the micro-volume 707. Further, it will be appreciated that the vertical position of the pedestal 708 and / or the showerhead 706 may be altered by any suitable mechanism within the scope of the present disclosure. In some embodiments, the pedestal 708 may include a rotation axis for rotating the orientation of the substrate 712. It will be appreciated that in some embodiments, one or more of these exemplary adjustments may be implemented programmatically by one or more suitable computer controllers.

[0118] Returning to the embodiment shown in FIG. 7, the showerhead 706 and pedestal 708 are in electrical communication with an RF power source 714 and a matching network 716 for powering the plasma. In other embodiments, an apparatus without a plasma generator is used to deposit molybdenum-containing films using the methods provided. In some embodiments, the plasma energy may be controlled by controlling one or more of the process station pressure, gas concentration, radio frequency (RF) source power, RF source frequency, and plasma power pulse timing. For example, the RF power source 714 and the matching network 716 may be operated at any suitable power to form a plasma having a desired composition of radical species. Similarly, the RF power source 714 may provide RF power of any suitable frequency. In some embodiments, the RF power source 714 may be configured to independently control the high frequency RF power source and the low frequency RF power source. Exemplary low frequency RF frequencies include, but are not limited to, frequencies between 50 kHz and 700 kHz. Exemplary high frequency RF frequencies 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 adjusted, either discretely or continuously, to provide plasma energy for surface reactions. In one non-limiting example, the plasma power may be pulsed intermittently to reduce ion collisions with the substrate surface compared to a continuously powered plasma.

[0119] In some embodiments, the plasma may be monitored in situ by one or more plasma monitors. In one scenario, the plasma power may be monitored by one or more voltage, current sensors (e.g., VI probes). In another scenario, the 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, OES sensors may be used in a feedback loop to provide programmatic control of the 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 include, but are not limited to, infrared (IR) monitors, acoustic monitors, and pressure transducers.

[0120] In some embodiments, the plasma may be controlled via input / output control (IOC) sequence instructions. In one example, instructions for setting plasma conditions for a plasma process stage may be included in a corresponding plasma activation recipe stage of a deposition process recipe. In some cases, the process recipe stages may be arranged in a sequence, such that all instructions for a deposition process stage are executed simultaneously with that process stage. In some embodiments, instructions for setting one or more plasma parameters may be included in a recipe stage preceding the plasma process stage. For example, a first recipe stage may include instructions for setting flow rates of inert and / or reactant gases, instructions for setting a plasma generator to a power set point, and a time delay instruction for the first recipe stage. A subsequent second recipe stage may include instructions for enabling the plasma generator and a time delay instruction for the second recipe stage. A third recipe stage may include instructions for disabling the plasma generator and a time delay instruction for the third recipe stage. It will be appreciated that these recipe stages may be further subdivided and / or repeated in any suitable manner within the scope of the present disclosure.

[0121] In some embodiments, the pedestal 708 may be temperature controlled via a heater 710. Additionally, in some embodiments, pressure control of the deposition process station 700 may be provided by a butterfly valve 718. As shown in the embodiment of FIG. 7, the butterfly valve 718 throttles the vacuum provided by a downstream vacuum pump (not shown). However, in some embodiments, pressure control of the process station 700 may also be adjusted by varying the flow rate of one or more gases introduced to the process station 700.

[0122] FIG. 8 shows a schematic diagram of an embodiment of a multi-station process tool 800 including an inbound load lock 802 and an outbound load lock 804, either or both of which may include a remote plasma source. Such a tool may be used to process substrates using the methods provided herein. A robot 806 is configured to move a wafer from a cassette loaded through a pod 808 at atmospheric pressure to the inbound load lock 802 through an atmospheric pressure port 810. The wafer is placed by the robot 806 on a pedestal 812 of the inbound load lock 802, the atmospheric pressure port 810 is closed, and the load lock is pumped down. If the inbound load lock 802 includes a remote plasma source, the wafer may undergo a remote plasma treatment in the load lock before being introduced to the process chamber 814. Additionally, the wafer may also be heated in the inbound load lock 802, for example, to remove moisture and adsorbed gases. The chamber transfer port 816 to the process chamber 814 is then opened and another robot (not shown) moves the wafer into the reactor and places it on the pedestal of the first station shown in the reactor for processing. Note that although the embodiment shown in Figure 8 includes a load lock, it will be appreciated that in some embodiments the wafer may enter the process station directly.

[0123] The illustrated process chamber 814 includes four process stations, numbered 1 through 4 in the embodiment shown in FIG. 8. Each station has a heated pedestal (shown at 818 for station 1) and a gas line inlet. It will be appreciated that in some embodiments, each process station may have a different purpose or multiple purposes. Although the illustrated process chamber 814 includes four stations, it will be understood that a process chamber according to the present disclosure may have any suitable number of stations. For example, in some embodiments, a process chamber may have five or more stations, while in other embodiments, a process chamber may have three or fewer stations.

[0124] FIG. 8 also illustrates one embodiment of a wafer handling system 890 for transferring wafers within the process chamber 814. In some embodiments, the wafer handling system 890 may transfer wafers between various process stations and / or between process stations and load locks. It will be appreciated that any suitable wafer handling system may be used. Non-limiting examples include a wafer carousel and a wafer handling robot. FIG. 8 also illustrates one embodiment of a system controller 850 used to control the process conditions and hardware states of the process tool 800. The system controller 850 may include one or more memory devices 856, one or more mass storage devices 854, and one or more processors 852. The processor 852 may include a CPU or computer, analog and / or digital input / output connections, stepper motor controller boards, etc.

[0125] In some embodiments, system controller 850 controls all of the activity of process tool 800. System controller 850 executes system control software 858 stored in mass storage device 854, loaded into memory device 856, and executed by processor 852. System control software 858 may include instructions for controlling the timing, mixture of gases, chamber and / or station pressures, chamber and / or station temperatures, purge conditions and purge timing, wafer temperature, RF power levels, RF frequency, substrate, pedestal, chuck and / or susceptor positions, and other parameters of a particular process performed by process tool 800. System control software 858 may be configured in any suitable manner. For example, various process tool component subroutines or control objects may be written to control the operation of process tool components necessary to perform various process tool processes according to the disclosed methods. System control software 858 may be coded in any suitable computer readable programming language.

[0126] In some embodiments, system control software 858 may include input / output control (IOC) sequence instructions for controlling the various parameters described above. For example, each stage of an ALD process may include one or more instructions for execution by system controller 850. Instructions for setting process conditions for an ALD process stage may be included in the corresponding ALD recipe stage. In some embodiments, the ALD recipe stages may be arranged sequentially such that all instructions for an ALD process stage are executed simultaneously with that process stage.

[0127] In some embodiments, other computer software and / or programs stored on the mass storage device 854 and / or memory device 856 associated with the system controller 850 may be used. 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.

[0128] The substrate positioning program may include program code for process tool components used to load the substrate onto the pedestal 818 and control the spacing between the substrate and other parts of the process tool 800 .

[0129] The process gas control program may include code for controlling gas composition and flow rates to stabilize the pressure of the process station, and optionally code for flowing gas to one or more process stations prior to deposition. The process gas control program may include code for controlling the gas composition and flow rates within any of the disclosed ranges. The pressure control program may include code for controlling the pressure of the process station, for example, by adjusting a throttle valve in the exhaust system of the process station, gas flow to the process station, etc. The pressure control program may include code for maintaining the pressure of the process station within any of the disclosed pressure ranges.

[0130] The heater control program may include code for controlling current to a heating unit used to heat the substrate. Alternatively, the heater control program may control the supply of a thermally conductive gas (such as helium) to the substrate. The heater control program may include instructions for maintaining the temperature of the substrate within any of the disclosed ranges.

[0131] The plasma control program may include code for setting the RF power levels and frequencies supplied to the process electrodes of one or more process stations, for example using any of the RF power levels disclosed herein. The plasma control program may include code for controlling the duration of each plasma exposure.

[0132] In some embodiments, there may be a user interface associated with the system controller 850. The user interface may include a display screen, a graphical software display of equipment and / or process conditions, and user input devices such as a pointing device, keyboard, touch screen, microphone, etc.

[0133] In some embodiments, the parameters adjusted by the system controller 850 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 a user in the form of a recipe or may be entered using a user interface.

[0134] Signals for monitoring the process may be provided by analog and / or digital input connections of the system controller 850 from various process tool sensors. Signals for controlling the process may be output at analog and digital output connections of the process tool 800. Non-limiting examples of process tool sensors that may be monitored include mass flow controllers, pressure sensors (such as pressure gauges), thermocouples, etc. Appropriately programmed feedback and control algorithms may be used with data from these sensors to maintain process conditions.

[0135] Any suitable chamber may be used to practice the disclosed embodiments. Exemplary deposition equipment includes, but is not limited to, the Altus® line of equipment available from Lam Research, Fremont, Calif., or any of a variety of other commercially available processing systems. Two or more stations may perform the same function. Similarly, two or more stations may perform different functions. Each station may be designed / configured to perform a specific function / method as desired.

[0136] FIG. 9 is a block diagram illustrating a processing system suitable for performing a film deposition process, according to certain embodiments. The system 900 includes a transfer module 903. The transfer module 903 provides a clean pressurized environment to minimize the risk of contamination when substrates being processed are moved between various reactor modules. The transfer module 903 is fitted with two multi-station reactors 909 and 910, each capable of performing atomic layer deposition (ALD) and / or chemical vapor deposition (CVD) according to certain embodiments. The reactors 909 and 910 may include multiple stations 911, 913, 915, and 917 that may perform operations according to the disclosed embodiments, either continuously or non-continuously. The stations may include a heated pedestal or substrate support, one or more gas inlets or showerheads or distribution plates.

[0137] The transfer module 903 may be fitted with one or more single or multi-station modules 907 capable of performing plasma or chemical (non-plasma) pre-cleaning or any other process described in connection with the disclosed method. The modules 907 may be used for various treatments, as the case may be, to prepare the substrate for, for example, a deposition process. The modules 907 may also be designed / configured to perform various other processes, such as etching or polishing. The system 900 also includes one or more wafer source modules 901 that store unprocessed and processed wafers. An atmospheric robot (not shown) in the atmospheric transfer chamber 919 may initially retrieve the wafer from the source module 901 to the load lock 921. A wafer transfer device (typically a robot arm unit) in the transfer module 903 moves the wafer from the load lock 921 to the modules attached to the transfer module 903 and between the modules.

[0138] In various embodiments, a system controller 929 is used to control process conditions during deposition. The controller 929 typically includes one or more memory devices and one or more processors, which may include a CPU or computer, analog and / or digital input / output connections, stepper motor controller boards, etc.

[0139] The controller 929 may control all of the deposition apparatus activities. The system controller 929 implements system control software that includes sets of instructions for controlling the timing, mixture of gases, chamber pressure, chamber temperature, wafer temperature, radio frequency (RF) power levels, wafer chuck or pedestal position, and other parameters of a particular process. Other computer programs stored in memory devices associated with the controller 929 may be used in some embodiments.

[0140] Typically, there is a user interface associated with the controller 929. The user interface may include a display screen, a graphical software display of equipment and / or process conditions, and user input devices such as a pointing device, keyboard, touch screen, microphone, etc.

[0141] The system control logic may be configured in any suitable manner. In general, logic may be designed or configured in hardware and / or software. Instructions for controlling the drive circuitry may be hard-coded or provided as software. Instructions may be provided by "programming". Such programming is understood to include any form of logic, such as logic hard-coded in digital signal processors, application specific integrated circuits, and other devices that have specific algorithms implemented as hardware. Programming is also understood to include software or firmware instructions that may be executed on a general purpose processor. The system execution software may be coded in any suitable computer readable programming language.

[0142] The computer program code for controlling the germanium-containing reducing agent pulses, hydrogen flow, and tungsten-containing precursor pulses, as well as other processes in the process sequence, can be written in any conventional computer readable programming language (e.g., assembly language, C, C++, Pascal, Fortran, etc.). Compiled object code or script is executed by the processor to perform the tasks specified in the program. Also, as shown, the program code may be hard coded.

[0143] The controller parameters relate to process conditions such as, for example, process gas composition and flow rates, temperature, pressure, cooling gas pressure, substrate temperature, and chamber wall temperature. These parameters may be provided to a user in the form of a recipe and entered using a user interface. Signals for monitoring the process may be provided by analog and / or digital input connections of the system controller 929. Signals for controlling the process are output at analog and digital output connections of the deposition apparatus 900.

[0144] The system software may be designed or configured in many different ways. For example, various chamber component subroutines or control objects may be written to control the operation of chamber components necessary to carry out a deposition process (and possibly other processes) in accordance with disclosed embodiments. Examples of programs or sections of programs for this purpose include substrate positioning code, process gas control code, pressure control code, and heater control code.

[0145] In some implementations, the controller 929 is part of a system, such as may be part of the examples described above. Such systems may include semiconductor processing equipment, such as one or more process tools, one or more chambers, one or more platforms for processing, and / or specific processing components (wafer pedestals, gas flow systems, etc.). These systems may be integrated with electronics for controlling the operation of the systems before, during, and after processing of semiconductor wafers or substrates. The electronics may be referred to as a "controller" and may control various components or subcomponents of one or more systems. The controller 929 may be programmed to control any of the processes disclosed herein, such as supply of process gases, temperature settings (e.g., heating and / or cooling), pressure settings, vacuum settings, power settings, radio frequency (RF) generator settings in some systems, RF matching circuit settings, frequency settings, flow settings, fluid supply settings, position and operation settings, and wafer movement in and out of tools and other moving tools and / or load locks connected or coupled to a particular system, depending on the processing requirements and / or type of system.

[0146] Broadly, a controller may be defined as an electronic device having various integrated circuits, logic, memory, and / or software that receive instructions, issue instructions, control operations, enable cleaning operations, enable endpoint measurements, etc. Integrated circuits may include chips in the form of firmware that store program instructions, digital signal processors (DSPs), chips defined as application specific integrated circuits (ASICs), and / or one or more microprocessors, i.e., microcontrollers, that execute program instructions (e.g., software). Program instructions may be instructions communicated to the controller in the form of various individual settings (or program files) that define operational parameters for performing a particular process on or for a semiconductor wafer or for a system. The operational parameters may, in some embodiments, be part of a recipe defined by a process engineer to accomplish one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or one or more processing steps in the fabrication of a wafer die.

[0147] The controller, in some embodiments, may be part of, coupled to, or a combination of a computer that is integrated or coupled with the system or otherwise networked to the system. For example, the controller may be in the "cloud" or may be all or part of a fab host computer system. This allows for remote access of wafer processing. The computer may allow remote access to the system to monitor the current progress of a fabrication operation, review the history of past fabrication operations, review trends or performance criteria from multiple fabrication operations, modify parameters of a current process, set processing steps following a current process, or start a new process. In some examples, a remote computer (e.g., a server) may provide process recipes to the system over a network, which may include a local network or the Internet. The remote computer may include a user interface that allows for entry or programming of parameters and / or settings, which are then communicated from the remote computer to the system. In some examples, the controller receives instructions in the form of data, which specifies parameters for each processing step to be performed during one or more operations. It should be understood that the parameters may be specific to the type of process being performed and the type of tool that the controller is configured to interface with or control. Thus, as discussed above, the controller may be distributed, for example, by having one or more individual controllers that are networked together and cooperate toward a common purpose (such as the process and control described herein). An example of a distributed controller for such purposes would include one or more integrated circuits on the chamber that communicate with one or more integrated circuits that are remotely located (e.g., at the platform level or as part of a remote computer) and that are coupled to control the process in the chamber.

[0148] Without being limited thereto, exemplary systems include a plasma etch chamber or module, a deposition chamber or module, a spin rinse chamber or module, a metal plating chamber or module, a cleaning chamber or module, a bevel edge etch chamber or module, a physical vapor deposition (PVD) chamber or module, a chemical vapor deposition (CVD) chamber or module, an atomic layer deposition (ALD) chamber or module, an atomic layer etch (ALE) chamber or module, an ion implantation chamber or module, a tracking chamber or module, and any other semiconductor processing system that may be associated with or used in the fabrication and / or manufacturing of semiconductor wafers.

[0149] As described above, depending on the one or more process steps being performed by the tool, the controller may communicate with one or more other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, nearby tools, tools located throughout the factory, a main computer, another controller, or tools used for material transport to and from tool locations and / or load ports in a semiconductor manufacturing factory.

[0150] Further embodiments 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, solar panels, etc. Typically, although not necessarily, such apparatus and processes are utilized or performed together in a common manufacturing facility. Lithographic patterning of a film generally involves some or all of the following steps, each of which can be done using many available tools: (1) applying photoresist to a workpiece (i.e., substrate) using a spin-on or spray-on tool; (2) curing the photoresist using a hotplate or furnace or UV curing tool; (3) exposing the photoresist to visible or UV or X-ray light using a tool such as a wafer stepper; (4) developing the resist to selectively remove the resist, thereby patterning the resist, using a tool such as a wet bench; (5) transferring the resist pattern to the underlying film or workpiece by using a dry etching tool or a plasma-assisted etching tool; and (6) removing the resist using a tool such as an RF or microwave plasma resist stripper.

Claims

1. 1. A method for forming a molybdenum-containing layer on a semiconductor substrate, comprising: (a) introducing a molybdenum-containing precursor into a process chamber containing the semiconductor substrate, the molybdenum-containing precursor being Mo 2 L n wherein each L is independently selected from the group consisting of amidate, amidinate, and guanidinate ligands, n is 2 to 5, and the molybdenum-containing precursor comprises a plurality of molybdenum-molybdenum bonds; (b) reacting the molybdenum-containing precursor to form a molybdenum-containing layer on the semiconductor substrate; A method comprising:

2. 10. The method of claim 1, wherein the molybdenum-containing layer is molybdenum metal.

3. 2. The method of claim 1, wherein the molybdenum-containing precursor is Mo 2 L n wherein each L is independently an amidinate or guanidinate ligand, n is 2 to 5, and said amidinate ligand is: 【Chemistry 1】 wherein each R is independently selected from the group consisting of H, alkyl, fluoroalkyl, alkylsilyl, alkylamino, and alkoxy substituents, and said guanidinate ligand is: 【Chemistry 2】 wherein each R is independently selected from the group consisting of H, alkyl, fluoroalkyl, alkylsilyl, alkylamino, and alkoxy substituents.

4. 2. The method of claim 1, wherein the molybdenum-containing precursor is Mo 2 L 3 Or Mo 2 L 4 wherein L is an amidinate.

5. 2. The method of claim 1, wherein the molybdenum-containing precursor is Mo 2 L 3 Or Mo 2 L 4 wherein L is a guanidinate.

6. 10. The method of claim 1, wherein (b) comprises reacting the molybdenum-containing precursor with hydrogen (H 2 ) with

7. 10. The method of claim 1, wherein (b) comprises reacting the molybdenum-containing precursor with hydrogen (H 2 ), ammonia (NH 3 ), diborane (B 2 H 6 ), water, H 2 S, thiols, alcohols, amines, hydrazines, silanes (SiH 4 ) and disilane (Si 2 H 6 ) to form a layer of molybdenum metal.

8. 8. The method of claim 7, wherein the molybdenum metal is deposited by thermal ALD or PEALD.

9. 10. The method of claim 1, wherein the molybdenum-containing layer is conformally deposited on a substrate having recessed features.

10. 1. A method for forming a molybdenum-containing layer on a semiconductor substrate, comprising: (a) introducing a molybdenum-containing precursor into a process chamber containing the semiconductor substrate, the precursor comprising: Molybdenum, At least one halogen that forms a bond with molybdenum; at least one organic ligand comprising an element selected from the group consisting of N, O, and S that forms a bond with molybdenum; (b) reacting the molybdenum-containing precursor with at least one reactant to form molybdenum metal on the semiconductor substrate; A method comprising:

11. 11. The method of claim 10, wherein (b) comprises reacting the molybdenum-containing precursor with hydrogen (H 2 ), ammonia (NH 3 ), diborane (B 2 H 6 ), water, H 2 S, thiols, alcohols, amines, hydrazines, silanes (SiH 4 ) and disilane (Si 2 H 6 ) to form a layer of molybdenum metal.

12. 12. The method of claim 11, wherein (b) comprises: subjecting the molybdenum-containing precursor to a plasma treatment with hydrogen (H 2 ) with

13. The method of claim 10 , wherein the reaction in (b) is carried out only on the surface of the substrate.

14. 11. The method of claim 10, wherein the reaction in (b) is carried out on a surface of the semiconductor substrate, the method further comprising the steps of: adsorbing the molybdenum-containing precursor onto the substrate, removing unadsorbed molybdenum-containing precursor from the process chamber prior to the reaction, and removing the adsorbed molybdenum-containing precursor from a solution of water, alcohol, H2O, or the like. 2 and reacting the surface of the semiconductor substrate with a reactant selected from the group consisting of hydrogen (H 2 ) to form said layer of molybdenum metal.

15. 11. The method of claim 10, wherein the precursor is Mo(X). m (L) n where: each X is independently a halide selected from the group consisting of F, Cl, Br, and I; each L is independently an organic ligand selected from the group consisting of amidinates, amines, amidates, iminopyrrolidinates, diazadiene, β-iminoamides, α-iminoalkoxides, β-aminoalkoxides, β-diketiminates, β-ketoiminates, β-diketonates, thioethers, thiolates, dithiolates, dithiolenes, and pyrazolates; m is 1 to 4; and n is 1 to 3; method.

16. 1. A method for forming a molybdenum metal layer on a semiconductor substrate, comprising: (a) introducing a molybdenum-containing precursor into a process chamber containing the semiconductor substrate, the precursor comprising: Molybdenum, at least one sulfur-containing ligand that forms a molybdenum-sulfur bond with the molybdenum, said compound being free of molybdenum-carbon bonds; (b) reacting the molybdenum-containing precursor to form molybdenum metal on the semiconductor substrate; A method comprising:

17. 17. The method of claim 16, wherein in the precursor, molybdenum forms only molybdenum-sulfur bonds.

18. 17. The method of claim 16, wherein the at least one sulfur-containing ligand is selected from the group consisting of 18, 19, 20, 21, 22, 23, 24, 25, wherein each R is independently selected from the group consisting of H, alkyl, fluoroalkyl, alkylamino, alkylsilyl, and alkoxy.

19. 17. The method of claim 16, wherein (b) comprises reacting the molybdenum-containing precursor with hydrogen (H 2 ), ammonia (NH 3 ), diborane (B 2 H 6 ), water, H 2 S, thiols, alcohols, amines, silanes (SiH 4 ), disilane (Si 2 H 6 ), and hydrazine to form a layer of molybdenum metal.

20. 17. The method of claim 16, wherein the reaction in (b) is carried out on a surface of the semiconductor substrate, and the method further comprises the steps of adsorbing the molybdenum-containing precursor onto the substrate, removing unadsorbed molybdenum-containing precursor from the process chamber prior to the reaction, and removing the adsorbed molybdenum-containing precursor from a solution of water, alcohol, H 2 and reacting the surface of the semiconductor substrate with a reactant selected from the group consisting of hydrogen (H 2 ) to form said layer of molybdenum metal.

21. A precursor for deposition of a molybdenum-containing coating, said precursor comprising: Molybdenum, At least one halogen that forms a bond with molybdenum; At least one organic ligand comprising an element selected from the group consisting of N, O, and S that forms a bond with molybdenum; with the proviso that said compound is not a molybdenum complex containing both imide and guanidinate organic ligands simultaneously.

22. 22. The precursor of claim 21 , wherein the organic ligand is a bidentate ligand.

23. 22. The precursor of claim 21, wherein the precursor does not contain molybdenum-carbon bonds.

24. A precursor for deposition of a molybdenum-containing coating, said precursor comprising Mo 2 L n wherein each L is independently an amidinate or guanidinate ligand, n is 2 to 5, the precursor contains a plurality of molybdenum-molybdenum bonds, and the amidinate ligand is 【Chemistry 3】 wherein each R is independently selected from the group consisting of H, alkyl, fluoroalkyl, alkylsilyl, alkylamino, and alkoxy substituents, and said guanidinate ligand is: 【Chemistry 4】 wherein each R is independently selected from the group consisting of H, alkyl, fluoroalkyl, alkylsilyl, alkylamino, and alkoxy substituents.

25. 1. A system for processing a semiconductor substrate, comprising: (a) a process chamber having a substrate holder and one or more inlets for introducing reactants into the process chamber; and (b) a system controller, (i) program instructions for causing introduction of a molybdenum-containing precursor into the process chamber, the molybdenum-containing precursor being Mo 2 L n wherein each L is independently selected from the group consisting of amidate, amidinate, and guanidinate ligands, where n is 2 to 5, and the molybdenum-containing precursor comprises a plurality of molybdenum-molybdenum bonds; and (ii) program instructions for causing the reaction of the molybdenum-containing precursor to form a molybdenum-containing layer on the semiconductor substrate. System controller Including, the system.

26. 1. A system for processing a semiconductor substrate, comprising: (a) a process chamber having a substrate holder and one or more inlets for introducing reactants into the process chamber; and (b) a system controller, (i) program instructions for causing introduction of a molybdenum-containing precursor into the process chamber, the molybdenum-containing precursor comprising: Molybdenum, At least one halogen that forms a bond with molybdenum; at least one organic ligand comprising an element selected from the group consisting of N, O, and S that forms a bond with molybdenum; and (ii) program instructions for causing the reaction of the molybdenum-containing precursor to form a molybdenum-containing layer on the semiconductor substrate. System controller Including, the system.

27. 1. A system for processing a semiconductor substrate, comprising: (a) a process chamber having a substrate holder and one or more inlets for introducing reactants into the process chamber; and (b) a system controller, (i) program instructions for causing introduction of a molybdenum-containing precursor into the process chamber, the molybdenum-containing precursor comprising: Molybdenum, at least one sulfur-containing ligand that forms a molybdenum-sulfur bond with the molybdenum, said compound not including a molybdenum-carbon bond; and (ii) program instructions for causing the reaction of the molybdenum-containing precursor to form a molybdenum-containing layer on the semiconductor substrate. System controller Including, the system.

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