Catalyst enhanced molybdenum deposition and gap fill

Abstract

This paper describes a method for depositing metal films. A metal film is formed on a substrate characterized by a metal substrate and dielectric sidewalls. The formation of the metal film involves exposing the substrate to a metal precursor and a haloalkane catalyst while maintaining the substrate at the deposition temperature. The metal precursor has a decomposition temperature higher than the deposition temperature. The haloalkane includes carbon and halogens, and the halogens include bromine or iodine.

Description

Technical Field

[0001] The embodiments of this disclosure generally relate to methods for depositing metal films. Some embodiments of this disclosure are directed to methods for depositing metal films. Some embodiments of this disclosure relate to selective deposition of metal films. Some embodiments of this disclosure control the deposition location and / or rate by using plasma and / or thermal exposure conditions. Prior Technology

[0002] Driven by the demand for mobile and high-performance systems from emerging industries such as autonomous vehicles, virtual reality, and future mobile devices, the semiconductor industry is constantly striving to achieve continuous device miniaturization. To achieve this feat, new high-performance materials are needed to circumvent the inherent engineering, chemical, and physical challenges encountered when rapidly reducing features in microelectronic components.

[0003] In its current state, this technology involves filling the structure using CVD or electrochemical plating (ECP) processes. In CVD processes, where deposition occurs across the entire structure, pores are often formed due to roughness as the film fuses, leaving seams in the gaps. ECP processes are limited by size and the availability of processes for the desired materials.

[0004] Furthermore, with the evolution of semiconductor device design, the manufacturing of precision materials in the semiconductor industry has entered the era of atomic-level scale. At the atomic level, only a few dozen atoms are at stake, leaving virtually no room for error. This unprecedented challenge necessitates new material handling technologies with atomic-level precision. However, increasing the complexity of the process flows required in atomic-level device manufacturing significantly reduces throughput and increases manufacturing costs.

[0005] This paper proposes using the high current density of molybdenum (Mo) thin films for semiconductor and microelectronic device applications, such as embedded word lines in DRAM applications. Current main methods involve TiN full filling or W / TiN deposition. However, both methods face the challenge of high resistivity in next-generation, smaller structures. New low-resistivity filling materials are needed. Ru or Mo are the two main candidates. However, Ru is unstable at high temperatures and tends to pull up after thermal curing, leaving large bottom voids. This pull-up problem is primarily material-dependent and therefore not easily resolved. For Mo, the current common process uses molybdenum oxychloride (MoOCl₄) precursors and H₂ as a reducing agent. However, this process typically requires high temperatures (above 550°C), which exhibits rough surfaces and chamber instability. Furthermore, chlorine raises concerns about interfaces between microelectronic devices. Therefore, this technology requires new precursors and deposition methods to form reasonable molybdenum interstitial filling that is void-free after annealing. Summary of the Invention

[0006] One or more embodiments of this disclosure relate to a metal deposition method. A substrate having at least one feature including a bottom and sidewalls is exposed to alternating pulses of a zero-valent metal aromatic precursor and a haloalkane catalyst. The substrate is maintained at a deposition temperature to form a metal film on the bottom of the feature. The bottom of the feature comprises a metal and the sidewalls of the feature comprise a dielectric. The metal precursor has a decomposition temperature higher than the deposition temperature. The haloalkane comprises carbon and a halogen, and the halogen comprises bromine or iodine.

[0007] Additional embodiments of this disclosure relate to a method for forming a seamless gap fill. A second metal film is deposited in a feature on a substrate to partially fill the feature by means of the second metal film. The feature includes a bottom and at least one sidewall. The bottom includes a first metal, and the at least one sidewall includes a dielectric. A second metal film is selectively formed on the bottom relative to the at least one sidewall and has a top surface lower than the top surface of the dielectric. A liner is deposited on the sidewall above the second metal film of the feature. The feature is filled by the second metal film to cover the liner and the top surface of the dielectric. At least some of the second metal film and the liner are removed from the top surface of the dielectric and at least some of the dielectric to form a seamless gap fill. Simple Explanation of the Diagram

[0008] Therefore, the above-described features of this disclosure can be understood in detail by referring to the embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that the accompanying drawings illustrate only typical embodiments of this disclosure and should not be considered as limiting the scope of this disclosure, as other equally effective embodiments are permissible.

[0009] Figure 1 illustrates an exemplary manufacturing process for forming a metal layer using a dual-pulse cyclic deposition technique according to one or more embodiments of this disclosure.

[0010] Figure 2 illustrates an exemplary manufacturing process sequence for forming a molybdenum layer according to one or more embodiments of this disclosure.

[0011] Figure 3 illustrates a cross-sectional view of an exemplary substrate according to one or more embodiments of the present disclosure.

[0012] Figure 4 illustrates an exemplary method for filling seamless gaps according to one or more embodiments of this disclosure.

[0013] In additional figures, similar parts and / or features may have the same element symbol. Furthermore, various parts of the same type can be distinguished by following the element symbol with a dash and a second symbol, which distinguishes similar parts. If only the first element symbol is used in the specification, the description applies to any of the similar parts having the same first element symbol, regardless of the second element symbol. Implementation

[0014] Before describing several exemplary embodiments of this disclosure, it should be understood that this disclosure is not limited to the details of the construction or process routines set forth in the following description. This disclosure can have other embodiments and can be practiced or implemented in various ways.

[0015] As used herein, "substrate," "substrate surface," or the like refers to any substrate or material surface formed on a substrate on which a process is performed. For example, depending on the application, substrate surfaces on which processes can be performed include, but are not limited to, materials such as silicon, silicon oxide, stressed silicon, silicon on insulator (SOI), carbon-doped silicon oxide, silicon nitride, 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 to grind, etch, reduce, oxidize, hydroxylate (or otherwise generate or graft target chemical portions to impart chemical functionality), anneal, and / or bake substrate surfaces. In addition to processing directly on the substrate surface itself, in this disclosure, any of the disclosed film processing steps 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 this underlayer, as indicated by the context. Therefore, for example, in the case where a film / layer or part of a film / layer has been deposited onto the substrate surface, the exposed surface of the most recently deposited film / layer becomes the substrate surface. What constitutes a given substrate surface will depend on the material to be deposited and the specific chemicals used.

[0016] 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 the appended claims, the terms "reactive compound," "reactive gas," "reactive substance," "precursor," "process gas," and similar terms are used interchangeably to mean a substance having the ability to react with the substrate surface or materials on the substrate surface in a surface reaction (e.g., chemisorption, oxidation, reduction). The substrate or portions thereof are individually exposed to two or more reactive compounds in a reaction region introduced into a processing chamber. In time-domain ALD processes, 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 and then be degassed from the processing chamber. These reactive compounds are considered to be sequentially exposed to the substrate. During spatial ALD processes, different portions of the substrate surface or materials on the substrate surface are simultaneously exposed to two or more reactive compounds such that no given point on the substrate is substantially exposed to more than one reactive compound at the same time. As used in this specification and the appended claims, those skilled in the art will understand that the term "generally" as used in this context means that a small portion of the substrate may be simultaneously exposed to multiple reactive gases due to diffusion, and that such simultaneous exposure is unintended.

[0017] In one state of a time-domain ALD process, a first reactive 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 time delay. During each time delay, a purge gas (e.g., argon) is introduced into the processing chamber to purge the reaction region or otherwise remove any residual reactive compounds or reaction byproducts from the reaction region. Alternatively, the purge gas may flow continuously throughout the deposition process, such that only purge gas flows during the time delay between pulses of the reactive compounds. The reactive compounds are pulsed alternately until a 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 constitutes one cycle. The cycle can begin with compound A or compound B and continue in the corresponding order until a film of a predetermined thickness is achieved.

[0018] In one embodiment of the space ALD process, a first reactive gas and a second reactive gas (e.g., a metal precursor gas) 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 such that any given point on the substrate is exposed to both the first and second reactive gases.

[0019] As used in this specification and the appended claims, the terms "precursor," "reactant," "reactive gas," and similar terms may be used interchangeably to represent any gaseous substance that can react with the substrate surface.

[0020] Some embodiments of this disclosure provide methods for depositing high-purity metal films. The methods of various embodiments use atomic layer deposition (ALD) to provide pure or near-pure metal films. Although exemplary embodiments of this disclosure involve the deposition of molybdenum, it is believed that the principles of this disclosure enable the deposition of high-purity metal films regardless of the metal.

[0021] Some embodiments of this disclosure advantageously provide methods for depositing metal films with high purity. Therefore, these high-purity films exhibit properties similar to those of their associated bulk metallization materials. For example, some embodiments of this disclosure provide molybdenum films that are smoother and have lower resistance than molybdenum films deposited by conventional oxygen or hydrogen reaction processes. Some embodiments of this disclosure advantageously provide metal films that conformally fill gaps without seams.

[0022] Some embodiments of this disclosure advantageously provide the selective deposition of a high-purity metal film on a metallized surface above a dielectric surface. For example, selective deposition of a metal (e.g., molybdenum) on copper above a dielectric advantageously provides a copper capping layer without additional etching or photolithography steps. Additionally, selective deposition can also achieve bottom-up gap filling of features with metal contacts (e.g., trenches, vias) at the bottom and dielectric sidewalls.

[0023] Some embodiments of this disclosure advantageously provide the selective deposition of a high-purity metal film on a dielectric surface above a metallized surface. For example, selectively depositing metal on a dielectric material advantageously provides a metal layer on a barrier layer or other dielectric material in back-end applications.

[0024] Some embodiments of this disclosure provide stable metal-organic molybdenum (Mo) precursors having a halogen-containing catalyst for atomic layer deposition. Some embodiments provide a metal oxide chemical vapor deposition (MOCVD) process with good gap filling without voids after annealing.

[0025] Figure 1 depicts a general method for forming a metal film on a substrate according to one or more embodiments of this disclosure. Method 100 generally begins at 102, wherein a substrate to which a metal film is to be formed is provided and placed in a processing chamber. Providing a substrate for processing means placing the substrate in a position suitable for a deposition technique. For example, providing a substrate for processing in a chemical vapor deposition chamber means that the substrate is located on a suitable support and in a suitable processing chamber. As used herein, "substrate surface" means any substrate surface on which layers may be formed. A substrate surface may have one or more features formed thereon, one or more layers formed thereon, and combinations thereof. The substrate (or substrate surface) may be pretreated (e.g., by grinding, etching, reduction, oxidation, halogenation, hydroxylation, annealing, baking, or the like) before depositing the metal film.

[0026] 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 (e.g., liquid crystal displays, plasma displays, electroluminescent (EL) lamp displays), solar cell arrays, solar panels, light-emitting diode (LED) substrates, semiconductor wafers, or the like. In some embodiments, one or more additional layers may be disposed on the substrate so that a metal film can be formed at least partially thereon. For example, in some embodiments, layers comprising metals, nitrides, oxides, or similar or combinations thereof may be disposed on the substrate and a metal film may be formed on or on these layers.

[0027] At point 103, the substrate is exposed to a barrier compound, as appropriate. This process step is described in more detail below, and it may have selectivity for controlling the deposition process on the substrate, including metal and dielectric surfaces. In some embodiments, a barrier compound is not used to deposit a metal film on the substrate.

[0028] At position 104, a metal film is formed on the substrate. The metal film can be formed via a cyclic deposition process (e.g., atomic layer deposition (ALD) or the like). In some embodiments, forming a metal film via a cyclic deposition process may generally involve exposing the substrate individually to two or more process gases. In a time-domain ALD embodiment, each of the process gases is separated by a time delay / pause to allow components of the process gases to adhere to and / or react on the substrate surface. Alternatively, or in combination, in some embodiments, decontamination may be performed before and / or after the substrate is exposed to the process gases, wherein an inert gas is used to perform the decontamination. For example, a first process gas may be provided to the process chamber, followed by decontamination with an inert gas. Next, a second process gas may be provided to the process chamber, followed by decontamination with an inert gas. In some embodiments, an inert gas may be continuously supplied to the process chamber, and a first process gas may be introduced into the process chamber in doses or pulses, followed by a second process gas in doses or pulses. In these embodiments, a delay or pause may occur between the doses of the first and second process gases to allow continuous flow of the inert gas to purge the process chamber between process gas doses.

[0029] In a spatial ALD embodiment, exposure to each of the process gases occurs simultaneously for different portions of the substrate, such that one portion of the substrate is exposed to a first reactive gas while another portion is exposed to a second reactive gas (if only two reactive gases are used). The substrate moves relative to the gas delivery system such that each point on the substrate is sequentially exposed to the first and second reactive gases. In either a temporal ALD or spatial ALD embodiment, this sequence can be repeated until a predetermined layer thickness is formed on the substrate surface.

[0030] As used herein, "pulse" or "dose" is intended to represent the amount of source gas introduced into the process chamber intermittently or discontinuously. Depending on the duration of the pulse, the amount of a particular compound within each pulse may vary over time. A particular process gas may include a single compound or a mixture / combination of two or more compounds, such as the process gases described below.

[0031] The duration of each pulse / dose can be varied and adjusted to suit the volumetric capacity of the processing chamber and the capability of the vacuum system coupled to that chamber. Furthermore, the dosing time of the process gas can be varied based on the flow rate of the process gas, the temperature of the process gas, the type of control valve, the type of process chamber used, and the ability of the process gas components to adsorb onto the substrate surface. The dosing time can also be varied based on the type of layer being formed and the geometry of the components being formed. The dosing time should be long enough to provide sufficient compound volume to adsorb / chemisorb onto substantially the entire surface of the substrate and form a layer of process gas components thereon.

[0032] The process of forming a metal film at point 104 can be initiated by exposing the substrate to a first reactive gas. The first reactive gas includes a haloalkane and is exposed to the substrate for a first time period, as shown at point 106.

[0033] The haloalkane can be any suitable reactant used to adsorb a halogen layer on a substrate for subsequent reactions. In some embodiments, the haloalkane comprises carbon and a halogen. In some embodiments, the halogen comprises bromine or iodine. In some embodiments, the halogen is insoluble in the metal film. As used in this regard, the halogen insoluble in the metal film comprises less than or equal to about 2%, less than or equal to about 1%, or less than or equal to about 0.5% of the metal film on an atomic basis. In some embodiments, the haloalkane has the general formula RX, wherein R is an alkyl, alkenyl, aryl, or other carbon-containing group. In some embodiments, R comprises one to two, one to four, or one to six carbon atoms. In some embodiments, the haloalkane comprises iodoethane (C₂H₅I) or diiodomethane (CH₂I₂), iodomethane (CH₃I), iodopropane (C₃H₇I), iodobutane (C₄H₹I), or substantially composed thereof. If used in this regard, the specified substance, in moles, is composed of more than 95%, 98%, 99% or 99.5% of a haloalkane, excluding any inert diluent gas.

[0034] The haloalkane is delivered as a haloalkane-containing gas to the processing chamber. The haloalkane-containing gas can be supplied in one or more pulses or continuously. The flow rate of the haloalkane-containing gas can be any suitable flow rate, including but not limited to flow rates in the range of about 1 sccm to about 5000 sccm, or in the range of about 2 sccm to about 4000 sccm, or in the range of about 3 sccm to about 3000 sccm, or in the range of about 5 sccm to about 2000 sccm. The haloalkane-containing gas can be supplied at any suitable pressure, including but not limited to pressures in the range of about 5 mTorr to about 25 mTorr, or in the range of about 100 mTorr to about 20 mTorr, or in the range of about 5 mTorr to about 20 mTorr, or in the range of about 100 mTorr to about 1000 mTorr, or in the range of about 200 mTorr to about 500 mTorr.

[0035] The period during which the substrate is exposed to a haloalkane-containing gas can be any suitable amount of time necessary to allow the haloalkane to form a sufficient adsorption layer on the substrate surface(s). For example, the process gas may flow into the process chamber for a period of approximately 0.1 seconds to approximately 90 seconds. In some time-domain ALD processes, the substrate surface is exposed to a haloalkane-containing gas for a period ranging from approximately 0.1 seconds to approximately 90 seconds, or from approximately 0.5 seconds to approximately 60 seconds, or from approximately 1 second to approximately 30 seconds, or from approximately 2 seconds to approximately 25 seconds, or from approximately 3 seconds to approximately 20 seconds, or from approximately 4 seconds to approximately 15 seconds, or from approximately 5 seconds to approximately 10 seconds.

[0036] In some embodiments, an inert gas and a haloalkane-containing gas may be simultaneously supplied to the process chamber. The inert gas may be mixed with the haloalkane-containing gas (e.g., as a dilution gas) or supplied separately, and may be pulsed or constant flow. In some embodiments, the inert gas is supplied to the process chamber at a constant flow rate ranging from about 1 sccm to about 10,000 sccm. The inert gas may be any inert gas, such as argon, helium, neon, or combinations thereof.

[0037] The substrate temperature during deposition can be controlled, for example, by setting the temperature of the substrate support or base. In some embodiments, the substrate is maintained at a temperature in the range of about 0°C to about 600°C, or in the range of about 25°C to about 500°C, or in the range of about 50°C to about 450°C, or in the range of about 100°C to about 400°C, or in the range of about 200°C to about 400°C, or in the range of about 250°C to about 350°C. In some embodiments, the substrate is maintained at a temperature below the decomposition temperature of the metal precursor. In some embodiments, the substrate is maintained at a temperature below the decomposition temperature of the haloalkane. In some embodiments, the substrate is maintained at a temperature between the decomposition temperature of the haloalkane and the decomposition temperature of the metal precursor.

[0038] In one or more embodiments, the substrate is maintained at a temperature less than or equal to about 400°C, or less than or equal to about 350°C, or less than about 300°C. In one or more embodiments, the substrate is maintained at a temperature greater than or equal to about 250°C, or greater than or equal to about 300°C, or greater than about 350°C. In some embodiments, the substrate is maintained at a temperature of about 280°C.

[0039] In addition to the foregoing, additional process parameters can be adjusted while the substrate is exposed to a haloalkane-containing gas. For example, in some embodiments, the process chamber can be maintained at a pressure of about 0.2 Torr to about 100 Torr, or in the range of about 0.3 Torr to about 90 Torr, or in the range of about 0.5 Torr to about 80 Torr, or in the range of about 1 Torr to about 50 Torr.

[0040] Next, at 108, an inert gas can be used to purge the process chamber (especially in time-domain ALD). (This may not be necessary in spatial ALD processes because of the presence of a gas curtain that separates the reactive gases.) The inert gas can be any inert gas, such as argon, helium, neon, or the like. In some embodiments, the inert gas may be the same as or different from the inert gas supplied to the process chamber during the exposure of the substrate to a haloalkane-containing gas at 706. In embodiments where the inert gas is the same, purge can be performed by: diverting the first process gas into the process chamber; allowing the inert gas to flow through the process chamber; and purging any excess first process gas components or reaction byproducts from the process chamber. In some embodiments, the inert gas may be supplied at the same flow rate as the first process gas described above, or in some embodiments, the flow rate may be increased or decreased. For example, in some embodiments, an inert gas can be supplied to the process chamber at a flow rate of about 0 sccm to about 10,000 sccm to purify the process chamber. In a space-based ALD, a purifying gas curtain is maintained between the reactive gas flows, and purifying the process chamber may not be necessary. In some embodiments of space-based ALD processes, an inert gas can be used to purify the process chamber or an area of ​​the process chamber.

[0041] An inert gas flow facilitates the removal of any excess first process gas components and / or excess reaction byproducts from the self-made process chamber, preventing undesirable gas-phase reactions of the first and second process gases.

[0042] Next, at point 110, the substrate is exposed to a second process gas for a second time period. The second process gas includes a metal precursor that reacts with a halogen adsorption layer on the substrate surface to deposit a metal film. The second reactive gas may also be referred to as a metal precursor gas.

[0043] The metal precursor can be any suitable precursor for reacting with the adsorbed halogen layer on the substrate. In some embodiments, the metal precursor includes a metal center and one or more ligands. In some embodiments, the metal center includes one or more metal atoms. In other words, in some embodiments, the metal precursor is one or more of a dimer, trimer, or tetramer.

[0044] Some embodiments of the metal precursor include a molybdenum (Mo) precursor. In some embodiments, the molybdenum precursor includes (aromatic)₂Mo. Examples of suitable precursors include, but are not limited to, Mo(EtBz)₂, ​​Mo(Et₃Bz)₂, ​​Mo(Me₂Bz)₂, ​​Mo(Me₃Bz)₂, ​​and Mo(toluene)₂. In some embodiments, an iodine-related catalyst (e.g., CH₂I₂, C₂H₅I, CH₃I) flows co-flowing with the molybdenum precursor, either pulsed into the molybdenum precursor (or vice versa) or exposed separately from the molybdenum precursor.

[0045] As temperature increases, the thermal decomposition of the Mo precursor begins at 150°C, but results in a high impurity content and high resistivity. With further temperature increases, the resistivity begins to decrease, and MoC formation begins at 450°C. To obtain a purer Mo film rather than MoC, in some embodiments, a halogen-containing catalyst is incorporated to improve deposition.

[0046] In some embodiments, the typical process is an ALD process, in which Mo precursors and catalysts are introduced into the chamber as two alternating precursors, and purification occurs between the two alternating precursors. The iodine catalyst on the Mo metallized surface can break L-Mo bonds during the catalytic surface reaction to generate Mo-I bonds and ultimately form Mo-Mo. However, the thermal energy required to break the Mo-I bonds is high. Therefore, a high deposition temperature (e.g., 425°C to 475°C) is required.

[0047] In some embodiments, deposition occurs at a lower temperature (e.g., 250°C to 400°C), where the thermal energy is insufficient to break the Mo-I bonds. In such embodiments, the deposited film contains carbon, a large amount of iodine, and oxygen as impurities. In some embodiments, the film impurities are reduced by H₂ or H₂ radical annealing. The metal of the metal precursor corresponds to the metal of the deposited metal film. In some embodiments, the metal is selected from molybdenum, ruthenium, cobalt, copper, platinum, nickel, or tungsten. In some embodiments, the metal of the metal precursor has an oxidation state of 0. In other words, in some embodiments, the metal precursor comprises a zero-valent metal complex.

[0048] In some embodiments, the metal precursor is a metal aromatic hydrocarbon precursor. In some embodiments, the metal precursor is a molybdenum aromatic hydrocarbon compound. Suitable examples of molybdenum aromatic hydrocarbon compounds include, but are not limited to, Mo(EtBz)₂, ​​Mo(Et3Bz)₂, ​​Mo(Me₂Bz)₂, ​​Mo(Me₃Bz)₂, ​​and Mo(toluene)₂. In some embodiments, the aromatic ligand includes one or more of o-xylene, m-xylene, or p-xylene.

[0049] While the substrate is exposed to the metal precursor gas, additional process parameters can be adjusted. For example, in some embodiments, the process chamber can be maintained at a pressure of about 0.2 Torr to about 100 Torr, or in the range of about 0.3 Torr to about 90 Torr, or in the range of about 0.5 Torr to about 80 Torr, or in the range of about 1 Torr to about 50 Torr.

[0050] The metal precursor is delivered as a metal precursor gas to the processing chamber. The metal precursor gas can be supplied in one or more pulses or continuously. The flow rate of the metal precursor gas can be any suitable flow rate, including but not limited to flow rates in the range of about 1 sccm to about 5000 sccm, or in the range of about 2 sccm to about 4000 sccm, or in the range of about 3 sccm to about 3000 sccm, or in the range of about 5 sccm to about 2000 sccm. The metal precursor gas can be supplied at any suitable pressure, including but not limited to pressures in the range of about 5 mTorr to about 25 mTorr, or in the range of about 100 mTorr to about 20 mTorr, or in the range of about 5 mTorr to about 20 mTorr, or in the range of about 100 mTorr to about 1000 mTorr, or in the range of about 200 mTorr to about 500 mTorr.

[0051] The period during which the substrate is exposed to the metal precursor gas can be any suitable amount of time necessary to allow the metal precursor to react with the adsorbed halogen on the substrate surface. For example, the process gas may flow into the process chamber for a period of approximately 0.1 seconds to approximately 90 seconds. In some time-domain ALD processes, the substrate surface is exposed to the metal precursor gas for a period ranging from approximately 0.1 seconds to approximately 90 seconds, or from approximately 0.5 seconds to approximately 60 seconds, or from approximately 1 second to approximately 30 seconds, or from approximately 2 seconds to approximately 25 seconds, or from approximately 3 seconds to approximately 20 seconds, or from approximately 4 seconds to approximately 15 seconds, or from approximately 5 seconds to approximately 10 seconds.

[0052] In some embodiments, an inert gas and a metal precursor gas may be simultaneously supplied to the process chamber. The inert gas may be mixed with the metal precursor gas (e.g., as a dilution gas) or supplied alone, and may be pulsed or constant flow. In some embodiments, the inert gas is supplied to the processing chamber at a constant flow rate ranging from about 1 sccm to about 10,000 sccm. The inert gas may be any inert gas, such as argon, helium, neon, or combinations thereof.

[0053] Next, at 112, an inert gas can be used to purge the process chamber. The inert gas can be any inert gas, such as argon, helium, neon, or the like. In some embodiments, the inert gas may be the same as or different from the inert gas supplied to the process chamber during a previous process cycle. In embodiments where the inert gas is the same, purge can be performed by: diverting a second process gas into the process chamber; allowing the inert gas to flow through the process chamber; and removing any excess second process gas components or reaction byproducts from the process chamber. In some embodiments, the inert gas can be supplied at the same flow rate used in conjunction with the second process gas, or in some embodiments, the flow rate can be increased or decreased. For example, in some embodiments, the inert gas can be supplied to the process chamber at a flow rate greater than 0 sccm to about 10,000 sccm to purge the process chamber.

[0054] Although the general embodiment of the processing method shown in Figure 1 includes only two pulses of reactive gas, it should be understood that this is merely illustrative and additional pulses of reactive gas may be used. In some embodiments, the method is performed without using oxygen-containing reactive gas. The subprocess 104 includes a cycle. The cycle can be performed in any order, as long as the reactive gas is separated by purification of the processing chamber. In some embodiments, the metal film is deposited at a rate greater than or equal to about 0.2 Å / cycle, greater than or equal to about 0.3 Å / cycle, greater than or equal to about 0.4 Å / cycle, greater than or equal to about 0.5 Å / cycle, greater than or equal to about 0.6 Å / cycle, greater than or equal to about 0.7 Å / cycle, greater than or equal to about 0.8 Å / cycle, greater than or equal to about 0.9 Å / cycle, greater than or equal to about 1.0 Å / cycle, or greater than or equal to about 1.2 Å / cycle.

[0055] In some embodiments, the deposition process is performed as a thermal process without the use of plasma reactants. In other words, in some embodiments, the method is performed without plasma. In some embodiments, the deposition process is plasma-enhanced or incorporates the use of free radicals and / or ions generated in the distal plasma.

[0056] Next, at 114, it is determined whether the predetermined thickness of the metal film has been achieved. If the predetermined thickness has not been achieved, method 100 returns to 104 to continue forming the metal film until the predetermined thickness is reached. Once the predetermined thickness has been reached, method 100 may end or proceed to 116 for optional further processing (e.g., bulk deposition of another metal film). In some embodiments, the metal film may be deposited to form a total layer thickness of about 10 Å to about 10,000 Å, or in some embodiments, about 10 Å to about 1,000 Å, or in some embodiments, about 50 Å to about 5,000 Å.

[0057] In some embodiments, the metal layer comprises more than or equal to about 85 atomic percent of molybdenum, or more than or equal to about 90 atomic percent of molybdenum, or more than or equal to about 95 atomic percent of molybdenum, or more than or equal to about 98 atomic percent of molybdenum.

[0058] In some embodiments, the metal layer comprises less than or equal to about 5 atomic percent oxygen, or less than or equal to about 4 atomic percent oxygen, or less than or equal to about 3 atomic percent oxygen, or less than or equal to about 2 atomic percent oxygen, or less than or equal to about 1 atomic percent oxygen, or less than or equal to about 0.5 atomic percent oxygen, or less than or equal to about 0.25 atomic percent oxygen.

[0059] In some embodiments, the metal layer includes iodine in the range of about 0.02 atomic% to about 5 atomic% or less than or equal to about 1 atomic% of iodine.

[0060] In some embodiments, the metal layer comprises less than or equal to about 20 atomic percent of carbon, or less than or equal to about 15 atomic percent of carbon, or less than or equal to about 10 atomic percent of carbon, or less than or equal to about 5 atomic percent of carbon.

[0061] In some embodiments, the metal layer comprises more than or equal to about 90 atomic percent molybdenum, less than or equal to about 3 atomic percent oxygen, less than or equal to about 1 atomic percent iodine and less than or equal to about 10 atomic percent carbon.

[0062] In some embodiments, the metal layer has a resistivity of less than or equal to about 40 μohm-cm, or less than or equal to about 35 μohm-cm, or less than or equal to about 30 μohm-cm, or less than or equal to about 25 μohm-cm, or less than or equal to about 20 μohm-cm. In some embodiments, the metal layer comprises molybdenum and has a resistivity of less than or equal to about 40 μohm-cm, or less than or equal to about 35 μohm-cm, or less than or equal to about 30 μohm-cm, or less than or equal to about 25 μohm-cm, or less than or equal to about 20 μohm-cm.

[0063] In some embodiments, the metal film is further treated by annealing. Without being theoretically limited, it is believed that annealing the film at high temperatures in an Ar or H₂ atmosphere reduces carbon and halogen impurities in the metal film. In some embodiments, annealing the metal film in an atmosphere including argon or hydrogen (H₂) reduces the atomic concentration of carbon and / or halogen impurities.

[0064] Metal films deposited by some embodiments are smoother than those deposited by known oxygen-based deposition processes. In some embodiments, the metal film has a surface roughness that is less than or equal to about 10%, less than or equal to about 8%, less than or equal to about 5%, or less than or equal to about 2% of the thickness of the metal film.

[0065] Some embodiments of this disclosure selectively deposit a first metal film on a second metal surface over a first dielectric surface. These methods are similar to method 100 as described above, except that the provided substrate includes a first dielectric surface and a second metal surface. The first metal (of the metal film) and the second metal (of the substrate surface) may be the same metal or different metals. In some embodiments, the first metal is molybdenum, ruthenium, cobalt, copper, platinum, nickel, or tungsten, while the second metal is tungsten, cobalt, or copper.

[0066] The first dielectric surface can be formed of any suitable dielectric material. In some embodiments, the dielectric material comprises nitrogen or oxygen atoms. Without being theoretically limited, these materials are believed to react with haloalkane and prevent halogen adsorption onto the substrate surface in order to catalyze the reaction with the metal precursor. Thus, a very small metal film (if present) is formed on the dielectric surface.

[0067] In some embodiments, the deposition temperature is below the decomposition temperature of the haloalkane. Again, without being theoretically limited, it is believed that if the haloalkane decomposes, the halogen will be available to react with metal precursors on all surfaces (regardless of composition), resulting in the deposition of a metal film on all substrate surfaces, including dielectric surfaces. In some embodiments, the deposition temperature is at or above the decomposition temperature of the haloalkane.

[0068] Some embodiments of this disclosure selectively deposit a first metal film on a first dielectric surface over a second metal surface. These methods are similar to method 100 as described above, except that the provided substrate includes a first dielectric surface and a second metal surface and the substrate is exposed to a barrier compound at 103.

[0069] At position 103, a substrate comprising at least a second metal surface and a first dielectric surface is exposed to a barrier compound. The barrier compound may be any suitable compound for blocking deposition on the second metal surface. In some embodiments, the barrier compound comprises at least one triple bond between two carbon atoms. In other words, in some embodiments, the barrier compound comprises an alkyne. In some embodiments, the barrier compound has the general formula R'≡R"". In some embodiments, R' and R" are equivalent. In some embodiments, R' and / or R" are alkyl or other carbon-containing groups. In some embodiments, the barrier compound comprises 4 to 12 carbon atoms. In some embodiments, R' and / or R" are linear chains. In some embodiments, R' and / or R" are branched chains. In some embodiments, the barrier compound comprises 3-hexyne.

[0070] The first metal (of the metal film) and the second metal (of the substrate surface) may be the same metal or different metals. In some embodiments, the first metal is molybdenum, ruthenium, cobalt, copper, platinum, nickel or tungsten, and the second metal is tungsten, cobalt or copper.

[0071] The first dielectric surface may be formed of any suitable dielectric material. In some embodiments, the dielectric material includes nitrogen or oxygen atoms.

[0072] As previously described, in some embodiments, the deposition temperature is the decomposition temperature of the haloalkane or higher. In some embodiments, the deposition temperature is greater than or equal to about 250°C, greater than or equal to about 260°C, greater than or equal to about 270°C, greater than or equal to about 280°C, greater than or equal to about 290°C, or greater than or equal to about 300°C. In some embodiments, the deposition temperature is in the range of about 250°C to about 450°C, or in the range of about 300°C to about 400°C. In some embodiments, the deposition temperature is about 350°C.

[0073] As previously stated, without being constrained by theory, these materials are believed to react with haloalkanes and prevent halogen adsorption onto the substrate surface in order to catalyze the reaction with metal precursors. Therefore, very little metal film (if present) is formed on the dielectric surface.

[0074] However, when the deposition temperature is higher than the decomposition temperature of the haloalkane, halogen atoms are deposited across the entire substrate surface, thereby allowing deposition on the dielectric surface. In some embodiments, the metal surface is blocked by a barrier compound to allow very little (if any) metal film to form on the metal surface. Therefore, the deposition of the metal film is selective to the dielectric surface compared to the metal surface.

[0075] Generally, the deposition of high-purity metal films according to some embodiments can be understood as follows: A substrate maintained at the deposition temperature is exposed to a haloalkane (RX) to absorb R and X on the substrate, wherein R is a carbon-containing group and X is a halogen. R is desorbed in the form of RR or R-, leaving X adsorbed on the substrate. The substrate is exposed to a metal precursor ML, wherein M is a metal and L is a ligand. ML reacts with the adsorbed X to form MX on the substrate surface, releasing L. MX reacts with other MX portions on the substrate to form MM. This reaction can produce XX or X-. XX can be desorbed or purified. X- can remain on the surface for further reaction with ML.

[0076] Some embodiments of this disclosure advantageously provide a method for depositing conformal metal films on a substrate including a high aspect ratio structure. As used in this regard, the term "conformal" means that the thickness of the metal film is uniform across the substrate surface. As used in this specification and the appended claims, the term "substantially conformal" means that the thickness of the metal film does not vary by more than about 10%, 5%, 2%, 1%, or 0.5% relative to the average thickness of the film. In other words, a substantially conformal film has a conformality greater than about 90%, 95%, 98%, 99%, or 99.5%.

[0077] One or more embodiments of this disclosure are directed to memory devices including a molybdenum conductive layer. In some embodiments, the molybdenum conductive layer includes more than or equal to about 90 at.% molybdenum, less than or equal to about 3 at.% oxygen, less than or equal to about 1 at.% iodine, and less than or equal to about 10 at.% carbon, and a resistivity of less than or equal to about 40 μohm-cm.

[0078] In some embodiments, a molybdenum conductive layer is formed on a barrier layer. In some embodiments, the barrier layer has a thickness of less than or equal to about 10 Å, 20 Å, 30 Å, 40 Å, or 50 Å. In some embodiments, the molybdenum conductive layer is formed on a substrate without an intervening barrier layer.

[0079] The above disclosure relates to the deposition of metal films by sequential pulses of reactants. The following disclosure relates to the deposition of metal films by simultaneous or constant-current processes. In some embodiments, the sequential pulse method is an ALD method. In some embodiments, the simultaneous or constant-current method is a CVD method. Although the process steps differ, many of the reactants and process parameters are similar.

[0080] Figure 2 depicts a general method 200 for forming a metal film on a substrate according to one or more embodiments of this disclosure. Figure 3 depicts an exemplary substrate for processing according to one or more embodiments of this disclosure. Method 200 generally begins at 210, where a substrate 300 on which a metal film is to be formed is provided and placed into a processing chamber.

[0081] Referring to Figure 3, an exemplary substrate 300 is shown. In some embodiments, the substrate 300 has a substrate surface 305 having at least one feature 310. Feature 310 has sidewalls 312, 314 and a bottom 316. In some embodiments, a dielectric material 320 forms the sidewalls 312, 314, and a metallization material 330 forms the bottom 316. Those skilled in the art will recognize that the illustrated embodiment involves two sidewalls (as in a trench-like structure), but this disclosure is not limited to trenches. In some embodiments, the feature includes a circular mesoscopic window, which, technically, has a single circular sidewall that appears as two sidewalls in a cross-sectional view, as shown.

[0082] In some embodiments, substrate 300 may undergo one or more optional pretreatment steps. At 215, the substrate may, if applicable, have one or more layers formed on the substrate surface.

[0083] In some embodiments, a metal nitride liner is deposited in feature 310. In some embodiments, the metal nitride liner comprises titanium nitride. In some embodiments, the metal nitride liner has a thickness ranging from about 15 Å to about 40 Å. In some embodiments, the metal nitride liner has a thickness of about 20 Å or about 30 Å. In some embodiments, there is no liner formed in the feature prior to the formation of the metal film. In some embodiments, there is no liner between the metal film and the bottom of the feature.

[0084] In some embodiments, a seed layer is deposited on the surface of a substrate. In some embodiments, the seed layer is a conformal layer. In some embodiments, the seed layer is continuous. In some embodiments, the thickness of the seed layer is in the range of about 1 nm to about 5 nm, or in the range of about 1 nm to about 4 nm. In some embodiments, the seed layer comprises a molybdenum layer deposited by a known atomic layer deposition method. In some embodiments, the seed layer is deposited by an ALD cycle, the ALD cycle including molybdenum precursor exposure and haloalkane exposure along with interventional decontamination. In some embodiments, the seed layer is deposited by an ALD cycle, the ALD cycle including molybdenum precursor exposure and ammonia plasma exposure along with interventional decontamination.

[0085] In some embodiments, the bottom 316 comprises metal, and optional pretreatment includes a cleaning process. In some embodiments, the metal bottom 316 of the feature is cleaned to remove oxides from the metal before a metal film is formed in the feature.

[0086] At 220°, the substrate is exposed to a barrier compound, as appropriate. This process step is described in more detail below, and it may have selectivity for controlling the deposition process on substrates including metal and dielectric surfaces.

[0087] At 230, a metal film is formed on the substrate. The metal film of some embodiments is formed by exposing the substrate to a metal precursor and a haloalkane catalyst while maintaining the substrate at the deposition temperature. In some embodiments, the haloalkane catalyst and the metal precursor are exposed to the substrate simultaneously. In some embodiments, the metal precursor and the haloalkane catalyst are exposed to the substrate separately and sequentially. In embodiments with separate exposure, each "cycle" is a single exposure to the haloalkane catalyst and the metal precursor, in any order. The process of forming the metal film at 230 can be initiated by immersing the substrate in a catalyst gas. The catalyst gas comprises a haloalkane and is exposed to the substrate for a first time period, as shown at 240. In some embodiments, the catalyst gas comprises a haloalkane catalyst that forms a catalyst layer on a characteristic metal substrate.

[0088] Alkyl halides can be any suitable reactant used to adsorb a layer on a substrate for subsequent reactions. In other words, immersing the substrate in an alkane halide creates an activated substrate surface. Alkyl halides have been described above and elsewhere in this document.

[0089] The haloalkane can be supplied to the processing chamber in one or more pulses or continuously. In some embodiments, the haloalkane has an inert carrier gas, referred to as a haloalkane-containing gas. The flow rate and pressure of the haloalkane or haloalkane-containing gas can be any suitable value. The exemplary flow rates and pressures disclosed elsewhere herein for haloalkane-containing gases also apply in this embodiment.

[0090] The immersion period of the substrate in the haloalkane can be any suitable amount of time necessary to allow the haloalkane to form a sufficient adsorption layer on the substrate surface(s). For example, the immersion period of the haloalkane in the substrate can be greater than about 3 seconds or greater than about 5 seconds. In some embodiments, the immersion period is in the range of about 3 seconds to about 60 seconds.

[0091] In some embodiments, an inert gas and a haloalkane-containing gas may be simultaneously supplied to the process chamber. The inert gas may be mixed with the haloalkane (e.g., as a dilution gas) or supplied alone, and may be pulsed or constant current. The inert gas may be any inert gas, such as argon, helium, neon, or combinations thereof.

[0092] Next, at 250°, the substrate is exposed to a second process gas for a second time period. The second process gas includes a metal precursor that reacts with an adsorbed layer of haloalkane or halogen on the substrate surface to deposit a metal film. The second reactive gas may also be referred to as a metal precursor gas.

[0093] The metal precursor can be any suitable precursor for reacting with the adsorbed haloalkane or halogen layer on the substrate. Suitable metal precursors are described elsewhere in this document.

[0094] The metal precursor is delivered as a metal precursor gas to the processing chamber. The metal precursor gas can be supplied in one or more pulses or continuously. The flow rate and pressure of the metal precursor gas can be any suitable flow rate and pressure. Illustrative values ​​for flow rate and pressure are discussed elsewhere in this document.

[0095] The exposure period of the substrate to the metal precursor gas can be any suitable amount of time necessary to allow the metal precursor to react with the adsorbed halogen on the substrate surface. For example, the process gas may flow into the process chamber for a period of about 60 seconds or more. In some embodiments, the exposure period to the metal precursor is about 100 seconds, about 200 seconds, about 300 seconds, about 400 seconds, or about 500 seconds.

[0096] Next, at 260, it is determined whether the metal film has achieved a predetermined thickness. If the predetermined thickness has not been achieved, method 200 returns to 250 to continue exposing the substrate to the metal precursor until the predetermined thickness is reached. Once the predetermined thickness has been reached, method 200 may end or proceed to 270 for optional further processing. In some embodiments, the metal film may be deposited to form a total layer thickness of about 10 Å to about 10,000 Å, or in some embodiments, about 20 Å to about 1,000 Å, or in some embodiments, about 50 Å to about 200 Å.

[0097] Some embodiments of this disclosure selectively deposit a metal film on a metal surface above a first dielectric surface. These methods are similar to method 200 as described above. The provided substrate includes a dielectric surface and a metal surface. In some embodiments, the substrate as shown in Figure 3 is processed to selectively form a bottom-up gap fill on the metal surface at the bottom 316 of feature 310.

[0098] The metal of the metal film and the metal on the substrate surface can be the same metal or different metals. The dielectric surface can be formed of any suitable dielectric material. In some embodiments, the dielectric material comprises nitrogen or oxygen atoms. Without being theoretically limited, it is believed that these materials react with haloalkanes and prevent halogens from adsorbing onto the substrate surface in order to catalyze the reaction with the metal precursor. Therefore, very little metal film (if present) is formed on the dielectric surface.

[0099] In some embodiments, the deposition temperature is below the decomposition temperature of the haloalkane. Again, without being theoretically limited, it is believed that if the haloalkane decomposes, the halogen will be available to react with metal precursors on all surfaces (regardless of composition), resulting in the deposition of a metal film on all substrate surfaces, including dielectric surfaces. In some embodiments, the deposition temperature is at or above the decomposition temperature of the haloalkane.

[0100] Some embodiments of this disclosure advantageously provide a method for controlling the deposition of a metal film. In some embodiments, the deposition rate is controlled. In some embodiments, the deposition location is controlled.

[0101] The methods of various embodiments use atomic layer deposition (ALD) or chemical vapor deposition (CVD) to form metal films. The above disclosure describes an illustrative ALD process with respect to Figure 1 and an illustrative CVD process with respect to Figure 2.

[0102] As previously described, the general deposition process shown in Figures 1 and 2 is performed as a thermal process without the use of plasma reactants. The use and effects of plasma and other additional reactants are further discussed below.

[0103] Some embodiments of this disclosure advantageously provide a method for depositing a metal film within a substrate feature or other structure. Exemplary features or structures include, but are not limited to, trenches and mesoscopic windows.

[0104] Some embodiments of this disclosure advantageously provide deposition control methods for reducing film deposition on the exterior of a target feature and near feature openings. Without being theoretically limited, it is believed that reducing deposition in these areas allows for faster gap filling within the target feature and reduces clogging near feature openings and the formation of voids or seams within the feature.

[0105] Referring to Figures 1 and 2, without limiting the scope of the above disclosures, both the ALD and CVD processes described above utilize alkyl halides and metal precursors to deposit metal films. Without being theoretically limited, it is believed that alkyl halides act as catalysts in the deposition of metal films. Therefore, as specifically demonstrated in CVD processes, a single exposure of the substrate surface to alkyl halides can be used to deposit metal films with a thickness greater than 10 nm.

[0106] Figure 4 illustrates a process for seamless gap filling according to one or more embodiments of this disclosure. The illustrated substrate 400 has at least one feature 405 having a first metal 410 at a bottom 406 of the feature 405 and at least one dielectric sidewall 420. The first metal 410 has a first metal surface 411 exposed within the feature 405. The dielectric sidewall 420 has a top surface 421 outside the feature 405 and one or more sidewall surfaces 422 inside the feature 405.

[0107] In some embodiments, substrate 400 is exposed to an optional cleaning process. The cleaning process cleans the first metal surface 411 at the bottom 406 of feature 405. In some embodiments, the cleaning process removes oxides from the first metal surface 411. Some embodiments of the cleaning process include degassing the substrate with or without hydrogen, argon sputtering with or without hydrogen, steam cleaning, or APC cleaning.

[0108] In some embodiments, a catalyst-enhanced chemical vapor deposition (CECVD) process is used to deposit a metal film 430. The metal film 430 (e.g., a molybdenum film) is selectively deposited on the first metal 410 to cover the first metal surface 411. The metal film 430 is deposited to a thickness that partially fills the feature 405 such that the top surface of the metal film 431 is lower than the top surface 421 of the dielectric 420.

[0109] A barrier layer 440 may be formed on the top surface 431 of the metal film 430. The barrier layer 440 may be any suitable material known to those skilled in the art, which prevents the deposition of liner material on the top surface 431 of the metal film 430. In some embodiments, the barrier layer 440 comprises a self-assembled monolayer (SAM).

[0110] In some embodiments, a conformal liner 450 is formed on the dielectric sidewalls 422 and top surface 421 of the dielectric 420. In some embodiments, a substantially non-conformal liner 450 is formed on the top surface 431 of the metal film 430 or the optional barrier layer 440. As used in this manner, the term "substantially non-conformal" means that less than or equal to about 10%, 5%, 2%, or 1% of the surface area of ​​the metal film 430 or the optional barrier layer 440 has a liner material deposited thereon. This excludes the edges of the sidewalls where they intersect the top surface of the metal film or the optional barrier layer. In some embodiments, the conformal liner 430 has a thickness of less than or equal to about 30 Å, 25 Å, or 20 Å. In some embodiments, the conformal liner 430 has a thickness sufficient to form a continuous film. In some embodiments, the conformal liner 430 comprises titanium nitride (TiN) and / or tantalum nitride (TaN).

[0111] In some embodiments, the barrier layer 440 may be removed from the top surface 431 of the metal film 430, as appropriate. The barrier layer 440 may be removed by any suitable technique known to a person skilled in the art.

[0112] In some embodiments, an overload 433 is formed by filling feature 405 with metal film 430, which covers conformal liner 450 on dielectric sidewalls and top surface of dielectric material.

[0113] In some embodiments, the metal film 430 is annealed as appropriate to alter some properties of the film and form an annealed metal film 460. For example, in some embodiments, the metal film 430 is annealed to increase the film density. Annealing can be performed under any suitable conditions and by any suitable technique known to those skilled in the art.

[0114] In some embodiments, a portion of the annealed metal film 460 (or metal film 430, if unannealed) is removed using any suitable technique. In some embodiments, a portion of the annealed metal film 460 (or metal film 430) and at least some of the conformal liner 450 are removed to expose the top surface 421 of the dielectric 420. In some embodiments, a portion of the annealed metal film 460 (or metal film 430) and a portion of the dielectric 420, as well as at least some of the conformal liner 450, are removed. In some embodiments, the entire conformal liner 450 is removed. In some embodiments, this portion of the annealed metal film 460 (or metal film 430), the conformal liner 450, and the dielectric 420 is removed by chemical mechanical planarization.

[0115] In some embodiments, one or more of a barrier layer 440 or a conformal liner 450 are deposited prior to the formation of the metal film 430, such that the barrier layer 440 is formed directly on the first metal 410. In some embodiments, the barrier layer 440 is removed from the surface of the first metal 410 prior to the deposition of the metal film 430. In some such embodiments, the deposition of the metal film 430 is performed with an initial ALD process, followed by a CECVD process to grow the metal film.

[0116] In some embodiments, a combination of atomic layer deposition (ALD) and catalyst-enhanced chemical vapor deposition (CECVD) is used. The ALD portion of some embodiments follows a sequence of metal precursor (e.g., molybdenum precursor) immersion, decontamination, catalyst precursor (e.g., iodine precursor) immersion, and decontamination. According to some embodiments, individual exposures during the ALD portion have short durations. In some embodiments, the immersion portion lasts less than 10 seconds, 5 seconds, 4 seconds, 3 seconds, or 2 seconds. In some embodiments, the metal precursor immersion is longer than the catalyst precursor immersion. In some embodiments, the decontamination portion lasts less than 5 seconds, 4 seconds, 3 seconds, 2 seconds, or 1 second. Regardless of coupling with the ALD segment, the CECVD portion of the process typically has longer pulse times and different pulse sequences. The CECVD sequence of some embodiments includes catalyst precursor immersion, followed by metal precursor immersion, and then decontamination. In some CECVD embodiments, the immersion of the catalyst precursor has a duration ranging from 5 to 300 seconds, 10 to 240 seconds, 15 to 210 seconds, 20 to 180 seconds, 25 to 120 seconds, or 30 to 60 seconds. In some embodiments, the immersion of the metal precursor in some CECVD embodiments has a duration ranging from 20 to 1200 seconds, 30 to 800 seconds, 40 to 600 seconds, 50 to 450 seconds, or 60 to 300 seconds. In some embodiments, the catalyst immersion has a shorter duration than the metal immersion. In some embodiments, the purging has a duration ranging from 1 to 100 seconds, 2 to 80 seconds, 3 to 60 seconds, 4 to 30 seconds, or 5 to 10 seconds.

[0117] In some embodiments, the process includes an initial ALD-type process to establish the thickness of the second metal. Once the predetermined thickness of the second metal has been formed, a CECVD process is repeatedly performed to grow a film having the predetermined thickness. In some embodiments, the CECVD process is ineffective for second metal growth in the absence of an initial layer of metal deposited by a selective ALD process. In some embodiments, the ALD-type sequence deposits the second metal at a faster rate than the CECVD process. In some embodiments, after the metal film 430 has been formed to a predetermined thickness (e.g., to the top of a feature), the process sequence switches to the ALD-type sequence. As described herein, the metal film may then be further processed.

[0118] In some embodiments, a combination of CVD and ALD processes is used to grow a molybdenum film. In some embodiments, the substrate is exposed to a gaseous mixture of molybdenum precursors and reactants. After a certain amount of film has been deposited, either the precursor or reactant stream is stopped, and deposition shifts to the ALD mechanism, in which there is substantially no gas-phase reaction between the molybdenum precursors and reactants.

[0119] Some embodiments of this disclosure are directed to 3D NAND devices, wherein word lines are formed using one or more embodiments of this disclosure. In some embodiments, bare word lines are deposited using one or more embodiments of this disclosure, and then the word lines are exposed as part of a memory element to rapid thermal processing at temperatures greater than 850°C, 900°C, 950°C, or 1000°C. In some embodiments, the RTP process has a duration of up to about 2 minutes, 1 minute, or 30 seconds, wherein the molybdenum film is not substantially pulled up.

[0120] Throughout this specification, references to "one embodiment," "some embodiments," "one or more embodiments," or "an embodiment" mean 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 one embodiment" appearing throughout this specification do not necessarily represent the same embodiment of this disclosure. Furthermore, particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments.

[0121] 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 this disclosure. Those skilled in the art will readily recognize that various modifications and variations can be made to the methods and apparatus of this disclosure without departing from the spirit and scope of this disclosure. Therefore, this disclosure is intended to include modifications and variations within the scope of the appended claims and their equivalents.

[0122] 100: Method 102: Steps 103: Steps 104: Steps 106: Steps 108: Steps 110: Steps 112: Steps 114: Steps 116: Steps 200: General Method 210: Steps 215: Steps 220: Steps 230: Steps 240: Steps 250: Steps 260: Steps 270: Steps 300:Substrate 305:Substrate surface 310: Features 312: Sidewall 314: Sidewall 316: Bottom 320: Dielectric material 330: Metallized materials 400:Substrate 405: Features 406: Bottom 410: First Metal 411: First metal thin film 420: Dielectric sidewall 421: Top surface 422: Sidewall surface 430:Metal film 431: Top surface 433: Overload 440: Barrier layer 450: Conformal Lining 460: Annealed metal film

[0123] Domestic storage information (please note in order of storage institution, date, and number) none Overseas storage information (please note in the order of storage country, institution, date, and number) none

Claims

1. A method for forming a seamless gap filler, the method comprising: depositing a metal film in a feature on a substrate by means of a process using a zero-valent metal aromatic precursor and a haloalkane catalyst to partially fill the feature by means of the metal film, the feature including a bottom and at least one sidewall, the bottom including a first metal and the at least one sidewall including a dielectric, the metal film being selectively formed on the bottom relative to the at least one sidewall, and the top surface of the metal film being lower than the top surface of the dielectric; depositing a liner on the at least one sidewall of the feature above the metal film and on the top surface of the dielectric, the liner being substantially not deposited on the top surface of the metal film within the feature; The feature is filled with the metal film to cover the liner and the top surface of the dielectric; and at least some of the liner and dielectric are removed from the top surface of the metal film and the dielectric, leaving some of the liner within the feature to form the seamless gap filler, wherein the first metal includes one or more of cobalt, tungsten, ruthenium, or molybdenum, and the metal film includes one or more of tungsten, ruthenium, or molybdenum.

2. The method as described in claim 1, wherein the zero-valent metal aromatic precursor comprises one or more metal atoms bonded to a benzene ring optionally substituted with an alkyl group and an open-ring or closed-ring diene.

3. The method as described in claim 1, wherein the haloalkane catalyst is substantially composed of iodoethane or diiodomethane.

4. The method as described in claim 1, wherein the zero-valent metal aromatic precursor and the haloalkane catalyst are exposed together to the substrate.

5. The method as described in claim 1, wherein the zero-valent metal aromatic precursor and the haloalkane catalyst are individually and sequentially exposed to the substrate in a cycle.

6. The method as described in claim 1, wherein the metal film has a growth rate greater than or equal to about 0.8 Å / cycle.

7. A method for forming a seamless gap filler, the method comprising: cleaning a first metal at a bottom of a feature on a substrate to remove oxide from the first metal, the feature including the bottom and at least one sidewall, the at least one sidewall including a dielectric; depositing a metal film in the feature on the substrate by means of a process using a zero-valent metal aromatic precursor and a haloalkane catalyst to partially fill the feature by means of the metal film, the haloalkane catalyst being exposed to the substrate prior to the zero-valent metal aromatic precursor, such that a catalyst layer is formed on the first metal at the bottom and, if appropriate, on the dielectric, and the metal film is selectively formed on the bottom relative to the at least one sidewall and has a top surface of the metal film being lower than a top surface of the dielectric; exposing the substrate having the catalyst layer on the bottom of the feature to an anisotropic etching, if appropriate, to remove any catalyst from the dielectric; A barrier layer is formed on the top surface of the metal film to prevent deposition on the top surface of the metal film; a liner is deposited on at least one sidewall of the feature above the metal film and on the top surface of the dielectric, the liner being substantially not deposited on the top surface of the metal film within the feature; the barrier layer is removed from the top surface of the metal film; the feature is filled with the metal film to cover the liner and the top surface of the dielectric; the metal film is annealed after filling the feature with the metal film; and the liner and at least some of the dielectric, the metal film, the top surface of the dielectric, and the liner are removed, leaving some of the liner within the feature to form a seamless gap fill, wherein the first metal includes one or more of cobalt, tungsten, ruthenium, or molybdenum, and the metal film includes one or more of tungsten, ruthenium, or molybdenum.

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