Molybdenum (iv) and molybdenum (iii) precursors for deposition of molybdenum films

Abstract

This invention describes molybdenum (IV) and molybdenum (III) coordination complexes. This invention also describes a method for depositing a molybdenum-containing film on a substrate. The substrate is exposed to a molybdenum precursor and reactants to form a molybdenum-containing film (e.g., elemental molybdenum, molybdenum oxide, molybdenum carbide, molybdenum silicide, molybdenum nitride). The exposure may be sequential or simultaneous.

Description

Technical Field

[0001] Embodiments of this disclosure relate to molybdenum precursors and methods for depositing molybdenum-containing thin films. More particularly, embodiments of this disclosure relate to molybdenum (IV) or molybdenum (III) complexes containing the pyrazolo, pyrazolato, guanidino, and iminato groups, and methods of using them. Background Technology

[0002] The semiconductor processing industry continues to demand higher production volumes while simultaneously increasing the uniformity of layers deposited on substrates with larger surface areas. These same factors, combined with new materials, also provide higher circuit integration density per unit area of ​​substrate. As circuit integration density increases, the need for greater uniformity in layer thickness and process control rises. As a result, various techniques have emerged to deposit layers on substrates cost-effectively while maintaining control over layer characteristics.

[0003] Chemical vapor deposition (CVD) is the most common deposition process used to deposit layers on substrates. CVD is a flux-dependent deposition technique that requires precise control of substrate temperature and the introduction of precursors into the processing chamber to produce the desired layer with uniform thickness. As substrate size increases, these requirements become increasingly critical, necessitating more sophisticated chamber designs and airflow techniques to maintain sufficient uniformity.

[0004] A variant of CVD exhibiting excellent stepped coverage is cyclic deposition or atomic layer deposition (ALD). Cyclic deposition is based on atomic layer epitaxy (ALE) and employs chemisorption techniques to deliver precursor molecules to the substrate surface in a continuous cycle. The cycle exposes the substrate surface to a first precursor, a purge gas, a second precursor, and another purge gas. The first and second precursors react to form product compounds as a film on the substrate surface. The cycle is repeated to form a layer to the desired thickness.

[0005] The increasing complexity of advanced microelectronic devices places stringent demands on current deposition techniques. Unfortunately, the number of available viable chemical precursors possessing the necessary properties of robust thermal stability, high reactivity, and suitable vapor pressures for film growth is limited. Furthermore, precursors that typically meet these requirements still exhibit poor long-term stability, leading to films containing elevated concentrations of contaminants such as oxygen, nitrogen, and / or halides, which are generally detrimental to the application of target films.

[0006] Molybdenum and molybdenum-based films possess attractive material and electrical properties. These films have been proposed and tested for applications in front-to-back-end components of semiconductors and microelectronic devices. Processing molybdenum precursors typically involves the use of halogen- and carbonyl-based substituents. These ligands provide sufficient stability at the cost of reduced reactivity and increased processing temperatures. Other molybdenum precursors include anionic nitrogen ligands, which can lead to the formation of nitride impurities. Therefore, this technology requires halogen- and carbonyl-free molybdenum precursors that react with the carbonyl group to form molybdenum metal and molybdenum-based films. Summary of the Invention

[0007] One or more embodiments of this disclosure relate to metal coordination complexes. In one or more embodiments, the metal coordination complex comprises molybdenum (IV) or molybdenum (III), and the metal coordination complex is substantially free of halogens and carbonyl groups.

[0008] One or more embodiments of this disclosure relate to a method for depositing a film. In one or more embodiments, a method for depositing a film protects: exposing a substrate to a molybdenum (IV) precursor or a molybdenum (III) precursor; and exposing the substrate to a reactant to form a molybdenum-containing film on the substrate.

[0009] Further embodiments of this disclosure relate to methods for depositing films. In one or more embodiments, a method for depositing a film includes forming a molybdenum-containing film in a process cycle, said process cycle including sequentially exposing a substrate to a molybdenum (IV) precursor or a molybdenum (III) precursor, a purge gas, reactants, and a purge gas. Attached Figure Description

[0010] Therefore, a more specific description of the present disclosure, which has been briefly summarized above, can be obtained by referring to the embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings only illustrate typical embodiments of the present disclosure and are therefore not intended to limit the scope of the present disclosure, as other equally effective embodiments are permissible.

[0011] Figure 1 A process flow diagram illustrating one or more embodiments of the method according to this disclosure is shown. Detailed Implementation

[0012] Before describing several exemplary embodiments of the present invention, it should be understood that the invention is not limited to the details of the construction or process steps set forth in the following description. The invention can have other embodiments and can be practiced or implemented in various ways.

[0013] Embodiments of this disclosure provide precursors and processes for depositing molybdenum-containing films. These metal coordination complexes of one or more embodiments are substantially free of halogens and carbonyl groups. Pyrazole / pyrazolo- or guanidino / imino ligands form thermally stable 18-electron complexes with molybdenum (IV) or molybdenum (III) atoms. Hydrogen bonds between the ligands provide additional stability under ALD and CVD conditions. The processes of various embodiments utilize vapor deposition techniques, such as atomic layer deposition (ALD) or chemical vapor deposition (CVD), to provide molybdenum films. The molybdenum precursors of one or more embodiments are volatile and thermally stable, thus suitable for vapor deposition.

[0014] As used herein, the term "substantially free" means that the molybdenum-containing membrane contains less than about 5% on an atomic basis, including less than about 4%, less than about 3%, less than about 2%, less than about 1%, and less than about 0.5% of halogens. In some embodiments, the molybdenum-containing membrane is substantially free of carbonyl groups and contains less than about 5% on an atomic basis, including less than about 4%, less than about 3%, less than about 2%, less than about 1%, and less than about 0.5% of carbonyl groups.

[0015] As used herein, “substrate” refers to any substrate on which a film treatment is performed during manufacturing, or a material surface formed on a substrate. For example, depending on the application, substrate surfaces on which treatment can be performed include materials such as silicon, silicon oxide, strained silicon, silicon on insulator (SOI), carbon-doped silicon oxide, amorphous silicon, doped silicon, germanium, gallium arsenide, glass, sapphire, and any other materials such as metals, metal nitrides, metal alloys, and other conductive materials. Substrates include, but are not limited to, semiconductor wafers. Substrates may be exposed to pretreatment processes such as polishing, etching, reduction, oxidation, hydroxylation, annealing, and / or baking of the substrate surface. In addition to film treatments performed directly on the surface of the substrate itself, any film treatment steps disclosed in this invention may also be performed on an underlayer formed on the substrate as disclosed in more detail below, and the term “substrate surface” is intended to include the underlayer as indicated in the context. Thus, for example, when a film / layer or a portion of a film / layer has already been deposited onto the substrate surface, the exposed surface of the newly deposited film / layer becomes the substrate surface.

[0016] According to one or more embodiments, the method uses an atomic layer deposition (ALD) process. In these embodiments, the substrate surface is exposed to the precursor (or reactant gas) sequentially or substantially sequentially. As used herein, “substantially sequentially” means that the majority of the duration of precursor exposure does not overlap with the exposure of the co-reagent, although some overlap may exist.

[0017] As used in this specification and the appended claims, the terms “precursor,” “reactant,” “reactive gas,” and similar terms are used interchangeably to refer to any gaseous species that can react with the surface of the substrate.

[0018] As used herein, “atomic layer deposition” or “cyclic deposition” refers to the sequential exposure of two or more reactive compounds to deposit a material layer on a substrate surface. As used in this specification and additional claims, the terms “reactive compound,” “reactive gas,” “reactive species,” “precursor,” “processing gas,” and similar terms are used interchangeably to refer to a substance having a species capable of reacting with the substrate surface or material on the substrate surface in a surface reaction (e.g., chemisorption, oxidation, reduction). The substrate or a portion of the substrate is sequentially exposed to two or more reactive compounds in a reaction region introduced into a processing chamber. In a time-domain ALD process, exposure to each reactive compound is separated by a time delay to allow each compound to adhere to and / or react on the substrate surface. In a spatial ALD process, different portions of the substrate surface or material on the substrate surface are simultaneously exposed to two or more reactive compounds so that any given point on the substrate is not substantially exposed to more than one reactive compound at the same time. As used in this specification and additional claims, and as understood by those skilled in the art, the term “substantially” in this context means the possibility that a small portion of the substrate may be simultaneously exposed to multiple reactive gases due to diffusion, and that simultaneous exposure is undesirable.

[0019] In one aspect of the time-domain ALD process, a first reactant gas (i.e., a first precursor or compound A) is pulsed into the reaction region, followed by a first time delay. Next, a second precursor or compound B is pulsed into the reaction region, followed by a second delay. During each time delay, a purge gas, such as argon, is introduced into the processing chamber to purge the reaction region or otherwise remove any remaining reactant compounds or byproducts from the reaction region. Alternatively, the purge gas may flow continuously throughout the deposition process, so that the purge gas flows only during the time delay between pulses of the reactant compounds. Alternatively, the reactant compounds may be pulsed until the desired film or film thickness is formed on the substrate surface. In either case, the ALD process of pulsed compound A, purge gas, compound B, and purge gas is a cycle. The cycle can begin with either compound A or compound B and continue in the corresponding sequence until a film with the desired thickness is achieved.

[0020] In one aspect of the space ALD process, a first reactant gas and a second reactant gas (e.g., hydrogen radicals) are simultaneously delivered to the reaction region but separated by an inert gas curtain and / or a vacuum curtain. The substrate is moved relative to the gas delivery device so that a given point on the substrate is exposed to the first and second reactant gases.

[0021] Without theoretical constraints, the presence of halogens, carbonyl groups, and in some cases oxygen in the molybdenum (Mo) precursor structure is considered potentially challenging, as halogen and oxygen contamination can affect device performance and thus require additional removal procedures. Carbonyl (CO) groups bind strongly to metals, requiring higher thermal budgets or the use of additional reagents for their removal. Carbonyl (CO) groups can also redeposit and damage other metal surfaces.

[0022] Molybdenum (Mo) can be grown by atomic layer deposition or chemical vapor deposition and is used in many applications. One or more embodiments of this disclosure advantageously provide a process for atomic layer deposition or chemical vapor deposition to form a molybdenum-containing film. As used in this specification and the additional claims, the term "molybdenum-containing film" refers to a film containing molybdenum atoms and having a molybdenum content greater than or equal to about 1 atomic % molybdenum, greater than or equal to about 2 atomic % molybdenum, greater than or equal to about 3 atomic % molybdenum, greater than or equal to about 4 atomic % molybdenum, greater than or equal to about 5 atomic % molybdenum, greater than or equal to about 10 atomic % molybdenum, greater than or equal to about 15 atomic % molybdenum, greater than or equal to about 20 atomic % molybdenum, greater than or equal to about 25 atomic % molybdenum, greater than or equal to about 30 atomic % molybdenum, greater than or equal to about 35 atomic % molybdenum, greater than or equal to about 40 atomic % molybdenum, greater than or equal to about 45 atomic % molybdenum, greater than or equal to about 50 atomic % molybdenum, or greater than or equal to about 60 atomic % molybdenum. In some embodiments, the molybdenum-containing film comprises one or more of molybdenum metal (elemental molybdenum), molybdenum oxide (MoO2, MoO3), molybdenum carbide (MoC, Mo2C), molybdenum silicide (MoSi2), or molybdenum nitride (Mo2N). Those skilled in the art will recognize that the use of materials such as MoSi... x A molecular formula does not imply a specific stoichiometric relationship between elements, but only signifies the similarity of the main components of the membrane. For example, MoSi... x This refers to a membrane whose main components include molybdenum and silicon atoms. In some embodiments, the main components of the membrane (i.e., the sum of the atomic percentages of specified atoms) are greater than or equal to about 95%, 98%, 99%, or 99.5% of the membrane on an atomic basis.

[0023] See Figure 1 One or more embodiments of this disclosure relate to a method for depositing a film. Figure 1The method shown represents an atomic layer deposition (ALD) process, in which a substrate or substrate surface is sequentially exposed to reactive gases in a manner that prevents or minimizes the gas-phase reaction of the reactive gases. In some embodiments, the method includes a chemical vapor deposition (CVD) process, in which reactive gases are mixed in a processing chamber to allow for the gas-phase reaction of the reactive gases and the deposition of a thin film.

[0024] In some embodiments, method 100 includes a pretreatment operation 105. The pretreatment can be any suitable pretreatment known to those skilled in the art. Suitable pretreatments include, but are not limited to, preheating, cleaning, soaking, removal of native oxides, or deposition of a binder layer (e.g., titanium nitride (TIN)). In one or more embodiments, a binder layer (such as titanium nitride) is deposited at operation 105.

[0025] At deposition 110, a process is performed to deposit a molybdenum-containing film on a substrate (or substrate surface). The deposition process may include one or more operations that form a film on the substrate. In operation 112, the substrate (or substrate surface) is exposed to a molybdenum precursor to deposit a film on the substrate (or substrate surface). The molybdenum precursor may be any suitable molybdenum-containing compound that can react with the substrate surface (i.e., adsorb or chemisorb onto the substrate surface) to leave molybdenum-containing species on the substrate surface.

[0026] Currently, molybdenum precursors used for metal film ALD employ halogen- and carbonyl-based substituents, which provide sufficient stability at the expense of reduced reactivity and increased process temperature. Other molybdenum precursors include anionic nitrogen ligands, which can lead to the formation of nitride impurities. Therefore, one or more embodiments use pyrazole / pyrazolone or guanidinyl / imino ligands to form thermally stable 18-electron complexes. Hydrogen bonds between the ligands provide additional stability. This combination provides molybdenum precursors with improved thermal stability while maintaining high volatility.

[0027] In one or more embodiments, the molybdenum precursor, particularly the molybdenum (IV) precursor or the molybdenum (III) precursor, has the structure of formula (I):

[0028] L is independently selected from the group consisting of pyrazole, pyrazolo, guanidine, and imino.

[0029] Without being constrained by theory, it is assumed that the ligands of pyrazoles and guanidines contain only nitrogen and carbon atoms, which allows for easier reduction of the molybdenum center compared to oxygen-containing molybdenum precursors. Furthermore, using different alkyl groups (R = iPr,tBu,-CH2tBu) can increase the volatility of the target species.

[0030] Unless otherwise stated, the terms “lower alkyl,” “alkyl,” or “alkane” as used herein, alone or as part of another group, include straight-chain and branched hydrocarbons containing 1 to 20 carbon atoms or 1 to 10 carbon atoms in the positive chain, such as methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, isobutyl, pentyl, hexyl, isohexyl, heptyl, 4,4-dimethylpentyl, octyl, 2,2,4-trimethylpentyl, nonyl, decyl, undecyl, dodecyl, and their various branched isomers. These groups may optionally include up to 1 to 4 substituents. Alkyl groups may be substituted or unsubstituted.

[0031] In a particular implementation, L is independently selected. The group consists of unsubstituted or substituted C1-C. 10 Alkyl group. In one or more embodiments, R may be independently selected from iPr-, tBu-, and Substituents.

[0032] In one or more embodiments, the metal coordination complex comprises the structure of formula (I). The structure of formula (I) may be selected from the group consisting of:

[0033]

[0034] As used herein, “substrate surface” means any substrate surface on which a layer may be formed. A substrate surface may have one or more feature structures formed therein, one or more layers formed thereon, and combinations thereof. The substrate (or substrate surface) may be pretreated prior to the deposition of a molybdenum-containing layer, for example by polishing, etching, reduction, oxidation, halogenation, hydroxylation, annealing, baking, or similar processes.

[0035] The substrate can be any substrate on which materials can be deposited, such as silicon substrates, III-V compound substrates, silicon-germanium (SiGe) substrates, epitaxial substrates, silicon-on-insulator (SOI) substrates, display substrates (such as liquid crystal displays (LCDs), plasma displays, electroluminescence (EL) lamp displays), solar cell arrays, solar panels, light-emitting diode (LED) substrates, semiconductor wafers, and similar substrates. In some embodiments, one or more additional layers may be disposed on the substrate such that a molybdenum-containing layer can be at least partially formed on the substrate. For example, in some embodiments, layers comprising metals, nitrides, oxides, or similar substances or combinations thereof may be disposed on the substrate, and may have a molybdenum-containing layer formed on said one or more layers.

[0036] At operation 114, the processing chamber is optionally purged to remove unreacted molybdenum precursors, reaction products, and byproducts. When used in this manner, the term "processing chamber" also includes the portion of the processing chamber near the substrate surface, but not the entire interior space of the processing chamber. For example, in a spatially separated sector of the processing chamber, the portion of the processing chamber adjacent to the substrate surface is purged of the molybdenum precursors using any suitable technique, including but not limited to moving the substrate through a gas curtain to a portion or sector of the processing chamber that does not contain or substantially does not contain molybdenum precursors. In one or more embodiments, purifying the processing chamber includes applying a vacuum. In one or more embodiments, the purge processing chamber includes a purge gas flowing over the substrate. In some embodiments, the portion of the processing chamber refers to a micro-volume or small-volume processing station within the processing chamber. The term "adjacent" when referring to the substrate surface means that the physical space next to the substrate surface provides sufficient space for surface reactions (e.g., precursor adsorption) to occur. In one or more embodiments, the purge gas is one or more selected from nitrogen (N2), helium (He), and argon (Ar).

[0037] At operation 116, the substrate (or substrate surface) is exposed to reactants to form one or more molybdenum films on the substrate. The reactants may react with molybdenum-containing species on the substrate surface to form a molybdenum-containing film. In some embodiments, the reactants comprise a reducing agent. In one or more embodiments, the reducing agent may comprise any reducing agent known to those skilled in the art. In other embodiments, the reactants comprise an oxidizing agent. In one or more embodiments, the oxidizing agent may comprise any oxidizing agent known to those skilled in the art. In a further embodiment, the reactants comprise one or more of an oxidizing agent and a reducing agent.

[0038] In specific embodiments, the reactants are selected from one or more of 1,1-dimethylhydrazine (DMH), alkylamines, hydrazine, alkylhydrazines, hydrogen (H2), ammonia (NH3), alcohols, water (H2O), oxygen (O2), ozone (O3), nitrous oxide (N2O), nitrogen dioxide (NO2), peroxides, and plasmas thereof. In some embodiments, the alkylamine is selected from one or more of tert-butylamine (tBuNH2), isopropylamine (iPrNH2), ethylamine (CH3CH2NH2), and diethylamine ((CH3CH2)2NH) or butylamine (BuNH2). In some embodiments, the reactants comprise one or more compounds of the formula R'NH2, R'2NH, R'3N, R'2SiNH2, (R'3Si)2NH, (R'3Si)3N; wherein each R' is independently H or an alkyl group having 1 to 12 carbon atoms. In some embodiments, the alkylamine is generally composed of one or more of tert-butylamine (tBuNH2), isopropylamine (iPrNH2), ethylamine (CH3CH2NH2), diethylamine ((CH3CH2)2NH), and butylamine (BuNH2).

[0039] At operation 118, the processing chamber is cleaned as appropriate after exposure to the reactants. The cleaning of the processing chamber in operation 118 can be the same process as the cleaning in operation 114 or a different process. The processing chamber, a portion of the processing chamber, the area near the substrate surface, etc., are cleaned to remove unreacted reactants, reaction products, and byproducts from the area near the substrate surface.

[0040] At decision 120, the thickness of the deposited film or the number of cycles of the molybdenum precursor and reactants are considered. If the deposited film has reached a predetermined thickness or a predetermined number of process cycles have been performed, method 100 moves to optional post-processing operation 130. If the thickness of the deposited film or the number of process cycles has not reached a predetermined threshold, method 100 returns to operation 110 to re-expose the substrate surface to the molybdenum precursor in operation 112 and continues.

[0041] Optional post-processing operation 130 may be, for example, a process that alters the properties of the film (e.g., annealing) or a further film deposition process (e.g., additional ALD or CVD process) to grow an additional film. In some embodiments, optional post-processing operation 130 may be a process that alters the properties of the deposited film. In some embodiments, optional post-processing operation 130 includes annealing the deposited film. In some embodiments, annealing is performed at temperatures in the range of about 300°C, 400°C, 500°C, 600°C, 700°C, 800°C, 900°C, or 1000°C. The annealing environment in some embodiments includes one or more of an inert gas (e.g., molecular nitrogen (N2), argon (Ar)) or a reducing gas (e.g., molecular hydrogen (H2) or ammonia (NH3)) or an oxidizing agent, such as, but not limited to, oxygen (O2), ozone (O3), or peroxides. Annealing may be performed for any suitable length of time. In some embodiments, the membrane is annealed for a predetermined time ranging from about 15 seconds to about 90 minutes, or from about 1 minute to about 60 minutes. In some embodiments, annealing the deposited membrane increases the membrane density, reduces the resistivity, and / or increases the membrane purity.

[0042] Method 100 can be performed at any suitable temperature, depending on the thermal budget of, for example, the molybdenum precursor, reactants, or device. In one or more embodiments, high-temperature processing may be undesirable for temperature-sensitive substrates such as logic devices. In some embodiments, exposure to the molybdenum precursor (operation 112) and reactants (operation 116) occurs at the same temperature. In some embodiments, the substrate is maintained at a temperature ranging from about 20°C to about 400°C, or from about 50°C to about 650°C.

[0043] In some embodiments, exposure to the molybdenum precursor (operation 112) occurs at a different temperature than exposure to the reactants (operation 116). In some embodiments, for exposure to the molybdenum precursor, the substrate is maintained at a first temperature in the range of about 20°C to about 400°C, or about 50°C to about 650°C; and for exposure to the reactants, the substrate is maintained at a second temperature in the range of about 20°C to about 400°C, or about 50°C to about 650°C.

[0044] exist Figure 1In the illustrated embodiment, at deposition operation 110, the substrate (or substrate surface) is sequentially exposed to the molybdenum precursor and reactants. In another embodiment, not shown, the substrate (or substrate surface) is simultaneously exposed to the molybdenum precursor and reactants during the CVD reaction. During the CVD reaction, the substrate (or substrate surface) may be exposed to a gaseous mixture of the molybdenum precursor and reactants to deposit a molybdenum-containing film of a predetermined thickness. In the CVD reaction, the molybdenum-containing film may be deposited in a single exposure to the mixed reactive gases, or through multiple exposures to the mixed reactive gases with purge between exposures.

[0045] In some embodiments, the formed molybdenum-containing film comprises elemental molybdenum. In other words, in some embodiments, the molybdenum-containing film comprises a metallic film containing molybdenum. In some embodiments, the metallic film is substantially composed of molybdenum. As used in this manner, the term "substantially composed of molybdenum" means that the molybdenum-containing film contains more than or equal to about 80%, 85%, 90%, 95%, 98%, 99%, or 99.5% molybdenum on an atomic basis. The measurement of the composition of the molybdenum-containing film refers to the bulk portion of the film, excluding the interfacial regions where elemental diffusion from adjacent films may occur.

[0046] In other embodiments, the molybdenum-containing film comprises molybdenum oxide (MoO₂) with an oxygen content of greater than or equal to about 5%, 7.5%, 10%, 12.5%, or 15% on an atomic basis. x In some embodiments, the molybdenum-containing membrane contains an oxygen content ranging from about 2% to about 30% on an atomic basis, or from about 3% to about 25%, or from about 4% to about 20%.

[0047] In other embodiments, the molybdenum-containing film comprises molybdenum carbide (MoC₂) with a carbon content of greater than or equal to about 5%, 7.5%, 10%, 12.5%, or 15% on an atomic basis. x In some embodiments, the molybdenum-containing membrane contains carbon in the range of about 2% to about 30% on an atomic basis, or in the range of about 3% to about 25%, or in the range of about 4% to about 20%.

[0048] Deposition operation 110 can be repeated to form one or more of a molybdenum oxide film, a molybdenum carbide film, a molybdenum silicide film, and a molybdenum nitride film having a predetermined thickness. In some embodiments, deposition operation 110 is repeated to provide a thickness in the range of about 0.3 nm to about 100 nm, or about to approximately One or more of the following: molybdenum oxide film, molybdenum carbide film, molybdenum silicide film, and molybdenum nitride film.

[0049] One or more embodiments of this disclosure relate to a method for depositing a molybdenum-containing film having a high aspect ratio feature structure. A high aspect ratio feature structure is a trench, via, or pillar having a height-to-width ratio greater than or equal to about 10, 20, or 50 or greater. In some embodiments, the molybdenum-containing film is conformally deposited on the high aspect ratio feature structure. When used in this manner, the conformal film has a thickness in the range of about 80 to 120% of the thickness at the bottom of the feature structure near the top.

[0050] Some embodiments of this disclosure pertain to a bottom-up gap-filling method for a feature structure. Bottom-up gap-filling processes fill the feature structure from the bottom, while conformal processes fill the feature structure from both the bottom and sides. In some embodiments, the feature has a first material (e.g., a nitride) at the bottom and a second material (e.g., an oxide) on the sidewalls. A molybdenum-containing film is selectively deposited on the first material relative to the second material so that the molybdenum film fills the feature structure in a bottom-up manner.

[0051] According to one or more embodiments, the substrate undergoes processing before and / or after the formation of the layer. This processing can be performed in the same chamber or in one or more separate processing chambers. In some embodiments, the substrate is moved from a first chamber to a separate second chamber for further processing. The substrate can be moved directly from the first chamber to the separate processing chamber, or the substrate can be moved from the first chamber to one or more transfer chambers and then to the separate processing chamber. Thus, the processing apparatus may include multiple chambers communicating with transfer stations. Such an apparatus may be referred to as a "clustering tool" or a "clustering system," etc.

[0052] Typically, clustering tools are modular systems comprising multiple chambers that perform various functions, including substrate centering and orientation, degassing, annealing, deposition, and / or etching. According to one or more embodiments, a clustering tool includes at least a first chamber and a central transfer chamber. The central transfer chamber houses a robot capable of reciprocating between or among a processing chamber and a load-locking chamber. The transfer chamber is typically maintained under vacuum and provides an intermediate platform for reciprocating the substrate from one chamber to another and / or to a load-locking chamber located at the front end of the clustering tool. Two well-known clustering tools applicable to this disclosure are both available from Applied Materials, Inc., of Santa Clara, California. and However, the precise arrangement and combination of chambers can be modified for the purpose of performing specific steps of the processes described herein. Other processing chambers that can be used include, but are not limited to, cyclical layer deposition (CLD), atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), etching, pre-cleaning, thermal treatments (such as RTP), plasma nitriding, degassing, orientation, hydroxylation, and other substrate processes. By performing the process in chambers on clustered tools, surface contamination of the substrate by atmospheric impurities in the unoxidized state can be avoided before the deposition of subsequent films.

[0053] According to one or more embodiments, the substrate is continuously kept under vacuum or "load-locked" conditions and is not exposed to ambient air as it moves from one chamber to the next. The transfer chamber is therefore under vacuum and "evacuated" under vacuum pressure. An inert gas may be present in the processing chamber or the transfer chamber. In some embodiments, the inert gas is used as a purge gas to remove some or all of the reactants (e.g., reactants). According to one or more embodiments, the purge gas is injected at the outlet of the deposition chamber to prevent multiple reactants (e.g., one reactant) from moving from the deposition chamber to the transfer chamber and / or to another processing chamber. Thus, the flow of the inert gas forms a curtain at the chamber outlet.

[0054] Substrates can be processed in a single substrate deposition chamber, where a single substrate is loaded, processed, and unloaded before processing another substrate. Similar to a conveyor system, substrates can also be processed continuously, where multiple substrates are individually loaded into a first portion of the chamber, moved through the chamber, and unloaded from a second portion of the chamber. The shape of the chamber and the associated conveyor system can form a straight path or a curved path. Alternatively, the processing chamber can be a disc conveyor belt, where multiple substrates move around a central axis and are exposed to processes such as deposition, etching, annealing, and cleaning throughout the disc conveyor path.

[0055] During processing, the substrate may be heated or cooled. This heating or cooling can be achieved by any suitable means, including but not limited to changing the temperature of the substrate support and flowing heated or cooled gas to the substrate surface. In some embodiments, the substrate support includes a heater / cooler that can be controlled to conductively change the substrate temperature. In one or more embodiments, the gas used (reactive gas or inert gas) is heated or cooled to locally change the substrate temperature. In some embodiments, the heater / cooler is located within a chamber adjacent to the substrate surface to convectively change the substrate temperature.

[0056] The substrate can be stationary or rotating during processing. The substrate can be rotated continuously or in discontinuous steps (around the substrate axis). For example, the substrate can be rotated throughout the entire process, or it can be rotated only slightly between exposures to different reaction or purge gases. Rotating the substrate during processing (continuously or in stages) can help produce more uniform deposition or etching by minimizing the effects of, for example, localized changes in airflow geometry.

[0057] The present disclosure will now be described with reference to the following examples. Before describing several embodiments of the present disclosure, it should be understood that the present disclosure is not limited to the details of the structures or process steps set forth in the following description. The present disclosure can have other embodiments and can be practiced or implemented in various ways.

[0058] Example

[0059] Example 1: Preparation of mixed pyrazolopyrazomolybdenum(IV) complexes

[0060] The mixed pyrazolopyrazomolybdenum(IV) complex was prepared by treating MoCl4(THF)2 with 4 equivalents of the corresponding alkyl-substituted potassium pyrazolate and 2 equivalents of alkyl-substituted pyrazole. The reaction mixture was stirred overnight, and then all volatiles were removed under vacuum. The target compound was extracted with toluene, and the solvent was removed under vacuum to give the target pyrazolopyrazomolybdenum(IV) precursor in good to moderate yields.

[0061] Example 2: Atomic layer deposition of molybdenum-containing thin films

[0062] General Procedure: A silicon substrate is placed in a processing chamber. A molybdenum precursor is introduced into the processing chamber in a nitrogen (N2) atmosphere over the silicon substrate, leaving a surface where the molybdenum precursor terminates. Unreacted precursors and byproducts are then removed from the chamber. Next, a co-reactant is introduced into the chamber, which reacts with the surface-bound molybdenum species. Again, excess co-reactant and byproducts are removed from the chamber. The resulting material on the substrate is a molybdenum-containing film.

[0063] For ease of description, spatial relative terms such as “beneath,” “below,” “lower,” “above,” “upper,” etc., may be used herein to describe the relationship between one element or feature and another, as shown in the figures. It should be understood that spatial relative terms are intended to include different orientations of the device in use or operation, other than those shown in the figures. For example, if the device in the figures were flipped, an element described as “beneath” or “below” would be oriented “above”. Thus, the exemplary term “beneath” can include both above and below orientations. The device may be oriented in other ways (rotated 90 degrees or otherwise), and the spatial relative descriptors used herein are interpreted accordingly.

[0064] In the context of describing the materials and methods discussed herein (particularly in the context of the above claims), the terms “a,” “an,” and “the,” and similar references, should be interpreted as covering both the singular and plural, unless otherwise stated herein or clearly contradicted by the context. Unless otherwise stated herein, the description of ranges of values ​​herein is intended only as a shorthand method of individually referring to each individual value falling within the said range, and each individual value is incorporated into the specification as if it were described separately herein. All methods described herein may be performed in any suitable order unless otherwise indicated herein or clearly contradicted by the context. The use of any and all instances or exemplary language provided herein (e.g., “such as”) is intended only to better elucidate the materials and methods and does not constitute a limitation on the scope unless otherwise required. No language in the specification should be construed as indicating that any unclaimed element is essential for the practice of the disclosed materials and methods.

[0065] Throughout this specification, references to "one embodiment," "some embodiments," "one or more embodiments," or "an embodiment" indicate that a particular feature, structure, material, or characteristic described in connection with that embodiment is included in at least one embodiment of this disclosure. Therefore, phrases such as "in one or more embodiments," "in some embodiments," "in one embodiment," or "in an embodiment" appearing throughout this specification do not necessarily refer to the same embodiment of this disclosure. In one or more embodiments, the particular feature, structure, material, or characteristic may be combined in any suitable manner.

[0066] Although the disclosure herein has been described with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the disclosure. It will be apparent to those skilled in the art that various modifications and variations can be made to the methods and apparatus of this disclosure without departing from the spirit and scope of the disclosure. Therefore, this disclosure is intended to include modifications and variations within the scope of the appended claims and their equivalents.

Claims

1. A metal coordination complex comprising molybdenum (IV), wherein the metal coordination complex has the structure of Formula (la): wherein R is C1-C 10 alkyl, wherein the metal coordination complex comprises less than 5% of halogen and carbonyl.

2. A method of depositing a film, the method comprising: exposing a substrate to a molybdenum (IV) precursor; and exposing the substrate to a reactant to form a molybdenum-containing film on the substrate, wherein the molybdenum (IV) precursor has the structure of Formula (la): wherein R is C1-C 10 alkyl.

3. The method of claim 2, wherein the reactant comprises one or more of an oxidizing agent and a reducing agent.

4. The method of claim 2, wherein the molybdenum film comprises one or more of a molybdenum metal film, a molybdenum oxide film, a molybdenum carbide film, a molybdenum silicide film, and a molybdenum nitride film.

5. The method of claim 2, wherein the substrate is sequentially exposed to the molybdenum (IV) precursor and the reactant.

6. The method of claim 2, wherein the substrate is simultaneously exposed to the molybdenum (IV) precursor and the reactant.

7. The method of claim 2, further comprising purging the molybdenum (IV) precursor from the substrate prior to exposing the substrate to the reactant.

8. The method of claim 7, wherein purging comprises one or more of applying a vacuum or flowing a purge gas over the substrate.

9. The method of claim 8, wherein the purge gas comprises one or more of nitrogen, helium, and argon.

10. The method of claim 2, further comprising repeating the method to provide a molybdenum-containing film having a thickness of 0.3 to 100 nm.

11. A method of depositing a film, the method comprising: forming a molybdenum-containing film in a process cycle, the process cycle comprising sequentially exposing a substrate to a molybdenum (IV) precursor, a purge gas, a reactant, and a purge gas, wherein the molybdenum (IV) precursor has the structure of Formula (la): wherein R is C1-C 10 alkyl.

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