Metal-containing film deposition and chamber cleaning

Abstract

A method for forming a metal-containing layer on a semiconductor substrate is provided, the method including: (a) co-flowing a metal-containing precursor and a reactant into a process chamber housing the semiconductor substrate, and (b) after (a), performing multiple cycles of flowing the reactant into the process chamber housing the semiconductor substrate, where the reactant does not react with the vapor phase metal-containing precursor. A method for cleaning a process chamber is also provided.

Description

[Background technology]

[0001] [Incorporated by reference] A PCT application is being filed contemporaneously herewith as a part of this application, and each application identified in that contemporaneously filed PCT application to which this application claims benefit or priority is hereby incorporated by reference in its entirety for all purposes. In integrated circuit (IC) fabrication, deposition and etching techniques are used to form patterns of materials, such as to form metal lines embedded in a dielectric layer. Some patterning methods require conformal deposition of materials, where the deposited layer must follow the contours of protruding and / or recessed features on the surface of the substrate. Atomic layer deposition (ALD) is often the preferred method for forming conformal films on substrates, because ALD relies on the adsorption of one or more reactants (precursors) to the surface of the substrate, followed by chemical conversion of the adsorbed layer into the desired material. Because ALD uses sequential reactions that occur on the surface of the substrate, are separated in time, and are typically limited by the amount of adsorbed reactants, the method can provide thin conformal layers with excellent step coverage.

[0002] Chemical vapor deposition (CVD) is another deposition method that is widely used in semiconductor processing. In CVD, the reaction occurs within the volume of the process chamber and is not limited by the amount of reactants adsorbed on the substrate. As a result, CVD-deposited films are often less conformal than ALD-deposited films. CVD is typically used in applications where step coverage is less critical.

[0003] ALD and CVD use plasma to drive the reaction of deposition precursors, resulting in the formation of the desired film. Methods that utilize plasma are known as plasma-enhanced ALD (PEALD) and plasma-enhanced CVD (PECVD). Methods that do not use plasma are called thermal ALD and thermal CVD.

[0004] Although ALD and CVD are most commonly used for the deposition of silicon-containing films such as silicon oxide, silicon nitride, and silicon carbide, these methods are also suitable for the deposition of some metals, most notably tungsten and cobalt.

[0005] Some semiconductor fabrication processes deposit a thin film on a substrate in a process chamber. The material of the thin film may also be deposited on the interior surfaces of the process chamber, thereby forming wall deposits. After the wall deposits reach a certain thickness or condition, typically after many wafers have been processed in the process chamber, the deposits may interfere with the deposition process. Therefore, it may be necessary to clean the wall deposits from the interior surfaces of the process chamber.

[0006] The background description provided herein is intended to provide a general overview of the contents of the present disclosure. Work by the currently named inventors within the scope of what is described in this Background section, as well as aspects of the description that may not otherwise be regarded as prior art at the time of filing, are not admitted, expressly or impliedly, as prior art against the present disclosure. Summary of the Invention

[0007] One aspect involves a method of forming a metal-containing layer on a semiconductor substrate, the method including: (a) co-flowing a metal-containing precursor and a reactant into a process chamber housing the semiconductor substrate; and (b) after (a), performing multiple cycles of flowing the reactant into the process chamber housing the semiconductor substrate, where the reactant does not react with the gas phase metal-containing precursor.

[0008] In some embodiments, (b) comprises reacting the surface-bound metal-containing precursor with a reactant in the absence of a plasma to form a metal-containing layer on the semiconductor substrate.

[0009] In some embodiments, the formed metal-containing layer is a substantially carbon-free molybdenum- or tungsten-containing layer having a carbon content of less than about 5 atomic %, and the layer is selected from the group consisting of Mo, W, MoN, WN, MoON, WON, MoB, WB, MoSi, WSi layers, and combinations thereof.

[0010] In some embodiments, the metal-containing precursor is a halide-free, carbonyl-free compound that includes at least one ligand bonded to a metal selected from the group consisting of molybdenum and tungsten.

[0011] In some embodiments, the halide-free, carbonyl-free compounds do not contain metal-carbon and metal-oxygen double bonds.

[0012] In some embodiments, the formed metal-containing layer has a carbon content of less than about 2 atomic percent.

[0013] In some embodiments, the metal-containing precursor does not include a beta hydrogen atom.

[0014] In some embodiments, the metal-containing layer formed is selected from the group consisting of Mo, MoN, and MoON.

[0015] In some embodiments, the reactant is hydrogen (H2).

[0016] In some embodiments, the reactants are introduced at a pressure of at least 10 Torr.

[0017] In some embodiments, the reactants are introduced at a pressure of at least 100 Torr.

[0018] Another aspect involves a method of cleaning a process chamber, the method including flowing a fluorine-containing species into the process chamber, the process chamber including a molybdenum-containing film formed on an inner surface of the process chamber, the method also including periodically or simultaneously flowing an oxygen-containing species into the process chamber along with the fluorine-containing species to clean the process chamber, the molybdenum-containing film being removed from the inner surface of the process chamber.

[0019] In some embodiments, the fluorine-containing species comprises nitrogen trifluoride (NF3), molecular fluorine (F2), carbon tetrafluoride (CF4), carbon hexafluoride (C2F6), xenon difluoride (XeF2), fluoromethane (CH3F), difluoromethane (CH2F2), tetrafluoroethylene (C2F4), hexafluoroethane (C2F6), octafluoropropane (C3F8), sulfur hexafluoride (SF6), a fluorine-containing plasma, or a mixture thereof.

[0020] In some embodiments, the oxygen-containing species comprises oxygen (O2), ozone (O3), carbon monoxide (CO), carbon dioxide (CO2), nitrous oxide (N2O), nitrogen dioxide (NO2), an oxygen-containing plasma, or a mixture thereof.

[0021] In some embodiments, the method also includes generating fluorine-containing radicals in the remote plasma source. The fluorine-containing species include fluorine-containing radicals. The method also includes generating oxygen-containing radicals in the remote plasma source. The oxygen-containing species include oxygen-containing radicals.

[0022] In some embodiments, the fluorine-containing species and the oxygen-containing species are cyclically flowed toward the interior surfaces of the process chamber.

[0023] In some embodiments, the fluorine-containing species and the oxygen-containing species are simultaneously co-flowed toward the interior surfaces of the process chamber.

[0024] In some embodiments, the method also includes depositing a molybdenum-containing layer on the substrate in the process chamber. After depositing the molybdenum-containing layer on the substrate, a molybdenum-containing film is formed on the interior surface of the process chamber.

[0025] In some embodiments, the molybdenum-containing layer is deposited on the substrate by atomic layer deposition (ALD), plasma-enhanced atomic layer deposition (PEALD), chemical vapor deposition (CVD), or plasma-enhanced chemical vapor deposition (PECVD).

[0026] In some embodiments, the method also includes transferring the substrate from the process chamber after depositing the molybdenum-containing layer and before cleaning the process chamber, and adjusting a chamber pressure of the process chamber to a high pressure regime of about 2 Torr to about 6 Torr or to a low pressure regime of about 0.5 Torr to about 2 Torr after transferring the substrate from the process chamber.

[0027] In some embodiments, the process chamber is cleaned at a first chamber pressure of about 2 Torr to about 6 Torr for a first period of time and at a second chamber pressure of about 0.5 Torr to about 2 Torr for a second period of time.

[0028] In some embodiments, over the first period of time, argon gas flows at a flow rate of about 1 to about 2 standard liters per minute, nitrogen trifluoride gas flows at a flow rate of about 0.5 to about 3 standard liters per minute, and oxygen gas flows at a flow rate of about 0.5 to about 2 standard liters per minute.

[0029] In some embodiments, during the second period of time, argon gas flows at a flow rate of about 0.5 to about 2 standard liters per minute, nitrogen trifluoride gas flows at a flow rate of about 0.5 to about 1.5 standard liters per minute, and oxygen gas flows at a flow rate of about 0.5 to about 1.5 standard liters per minute.

[0030] In some embodiments, the molybdenum-containing film comprises undoped or carbon-doped molybdenum oxide, undoped or carbon-doped molybdenum nitride, undoped or carbon-doped molybdenum oxynitride, or mixtures thereof, hi some embodiments, the molybdenum-containing film comprises molybdenum metal.

[0031] In some embodiments, the molybdenum-containing film comprises carbon and the oxygen-containing species oxidizes the carbon to remove it from the interior surfaces of the process chamber.

[0032] In some embodiments, the process chamber is at a temperature between about 200° C. and about 650° C. during cleaning of the process chamber.

[0033] In some embodiments, a first period of cleaning exposes the interior surfaces of the process chamber to a plasma of a fluorine-containing species and a plasma of an oxygen-containing species, and a second period of cleaning exposes the interior surfaces of the process chamber to the fluorine-containing species and the oxygen-containing species in a plasma-free environment.

[0034] In some embodiments, the molybdenum-containing film is formed by reducing a molybdenum oxynitride film with one or more reducing agents, where the one or more reducing agents include nitrogen, argon, hydrogen, ammonia, other hydrogen-containing gases, or mixtures thereof.

[0035] Yet another aspect involves a method of cleaning a process chamber, the method including providing a process chamber including an inner surface on which a carbon-containing molybdenum nitride film is deposited, exposing the inner surface of the process chamber to fluorine-containing radicals to react with the carbon-containing molybdenum nitride film and remove at least a portion of the carbon-containing molybdenum nitride film, and exposing the inner surface of the process chamber to oxygen-containing radicals to oxidize at least the carbon in the carbon-containing molybdenum nitride film. The fluorine-containing radicals and oxygen-containing radicals are generated from a remote plasma source fluidly coupled to the process chamber. The fluorine-containing radicals and oxygen-containing radicals are periodically or simultaneously co-flowed toward the inner surface of the process chamber to clean the process chamber.

[0036] In some embodiments, oxidizing the carbon includes producing carbon oxide, carbon dioxide, or a mixture thereof from the carbon-containing molybdenum nitride film.

[0037] In some embodiments, the fluorine-containing radicals and the oxygen-containing radicals are generated in a remote plasma source and co-flowed simultaneously into the process chamber.

[0038] In some embodiments, the process chamber is cleaned at a first chamber pressure of about 2 to about 6 Torr for a first period of time and at a second chamber pressure of about 0.5 to about 2 Torr for a second period of time.

[0039] In some embodiments, the method also includes depositing a molybdenum-containing layer on the substrate in the process chamber. A carbon-containing molybdenum nitride film is formed on the interior surface of the process chamber. Depositing the molybdenum-containing layer includes flowing a molybdenum-containing precursor from a first manifold into the process chamber. The method also includes cleaning the carbon-containing molybdenum nitride film from the interior surface of the process chamber by flowing fluorine-containing radicals and oxygen-containing radicals from a second manifold into the process chamber in the process chamber.

[0040] Yet another aspect involves an apparatus including a process chamber including a chuck configured to support a substrate, one or more gas outlets coupled to the process chamber and configured to introduce a fluorine-containing species and an oxygen-containing species into the process chamber, one or more remote plasma sources fluidly coupled to the process chamber by the one or more gas inlets, one or more second gas outlets coupled to the process chamber and configured to introduce a molybdenum-containing precursor into the process chamber, and a controller having at least one processor and a memory. The memory includes computer-executable instructions for controlling the at least one processor to flow a molybdenum-containing precursor into the process chamber through the one or more second gas outlets to expose the substrate to the molybdenum-containing precursor such that a molybdenum-containing film is deposited on the interior surfaces of the process chamber, introduce a fluorine-containing source gas into the one or more remote plasma sources to generate a plasma of a fluorine-containing species, introduce an oxygen-containing source gas into the one or more remote plasma sources to generate a plasma of an oxygen-containing species, and periodically or simultaneously flow the plasma of the fluorine-containing species and the plasma of the oxygen-containing species into the process chamber through the one or more first gas outlets, and remove the molybdenum-containing film from the interior surfaces of the process chamber.

[0041] In some embodiments, the apparatus also includes a chamber pressure gauge configured to maintain a first pressure in the process chamber when the molybdenum-containing precursor is flowed into the process chamber and configured to maintain a second pressure in the process chamber when the fluorine-containing species and the oxygen-containing species are flowed into the process chamber, the second pressure being in a low pressure regime of about 0.5 Torr to about 2 Torr or in a high pressure regime of about 2 Torr to about 6 Torr.

[0042] In some embodiments, the fluorine-containing source gas includes nitrogen trifluoride (NF3), molecular fluorine (F2), carbon tetrafluoride (CF4), carbon hexafluoride (C2F6), xenon difluoride (XeF2), fluoromethane (CH3F), difluoromethane (CH2F2), tetrafluoroethylene (C2F4), hexafluoroethane (C2F6), octafluoropropane (C3F8), sulfur hexafluoride (SF6), or mixtures thereof.

[0043] In some embodiments, the oxygen-containing source gas includes oxygen (O2), ozone (O3), carbon monoxide (CO), carbon dioxide (CO2), nitrous oxide (N2O), nitrogen dioxide (NO2), or mixtures thereof.

[0044] Yet another aspect involves a method of cleaning a dielectric material from one or more components of a process chamber, the method including: (a) introducing into the process chamber (i) a remote plasma including a fluorine species and (ii) a thermal etchant that undergoes a ligand exchange reaction with fluorine-containing reaction products of the dielectric material to generate volatile reaction products; and (b) removing the volatile reaction products from the process chamber.

[0045] In some embodiments, (a) includes co-flowing the remote plasma and the thermal etchant into the process chamber.

[0046] In some embodiments, the remote plasma and thermal etchant may be introduced for about 0.1 to about 600 seconds.

[0047] In some embodiments, (a) includes introducing a remote plasma into the process chamber a first time and then introducing a thermal etchant a second time. The method further includes repeating introducing a remote plasma into the process chamber a first time and introducing a thermal etchant a second time.

[0048] In some embodiments, the remote plasma may be introduced for about 30 to about 300 seconds, and the thermal etchant may be introduced for about 30 to about 300 seconds.

[0049] In some embodiments, (a) further comprises introducing water vapor, methyl alcohol, ethyl alcohol, or propyl alcohol into the process chamber.

[0050] In some embodiments, (i) introducing into the process chamber a remote plasma comprising a fluorine species comprises forming a dielectric material comprising fluorine ligands.

[0051] In some embodiments, conducting a ligand exchange reaction involves substituting fluorine in a fluorine-containing reaction product with bromine or chlorine.

[0052] In some embodiments, the method further includes pausing the semiconductor device fabrication process in the process chamber prior to (a).

[0053] In some embodiments, the remote plasma is generated from a process gas comprising nitrogen trifluoride, fluorine (F2), tetrafluoromethane, trifluoromethane, difluoromethane, fluoromethane, sulfur hexafluoride, octafluoropropane, octafluorocyclobutane, hexafluorocyclobutene, 1,2,3,3,4-pentafluorocyclobuten-4-yl radical, fluorine, or mixtures thereof.

[0054] In some embodiments, the thermal etchant comprises hydrogen bromide, hydrogen chloride, boron trichloride, or mixtures thereof.

[0055] In some embodiments, the thermal etchant comprises boron bromide, phosphorus trichloride, carbon tetrachloride, nitrogen trichloride, or mixtures thereof.

[0056] In some embodiments, the volatile reaction products include Br or Cl ligands.

[0057] In some embodiments, the chamber temperature is from about 50 to about 650°C.

[0058] In some embodiments, the chamber pressure is from about 0.5 to about 100 Torr.

[0059] In some embodiments, the etch rate of the dielectric material is from about 500 to about 1,000 angstroms per minute.

[0060] In some embodiments, the dielectric material comprises hafnium oxide, zirconium oxide, tin oxide, aluminum oxide, hafnium nitride, zirconium nitride, aluminum nitride, yttrium oxide, lanthanum oxide, or mixtures thereof.

[0061] In some embodiments, (a) includes exposing the dielectric material in the process chamber a first time to a remote plasma comprising a fluorine species and a second time to a thermal etchant.

[0062] In some embodiments, (a) includes exposing the dielectric material in a process chamber to a co-flow of a remote plasma and a thermal etchant.

[0063] Yet another aspect involves a system including a process chamber configured to perform a device fabrication operation to deposit a dielectric material on one or more components of the process chamber; a remote plasma source configured to generate a remote plasma comprising a fluorine-containing species and deliver the remote plasma to the process chamber; and a controller configured to (a) introduce into the process chamber (i) the remote plasma comprising the fluorine species and (ii) a thermal etchant that undergoes a ligand exchange reaction with fluorine-containing reaction products of the dielectric material to generate volatile reaction products, and (b) remove the volatile reaction products from the process chamber.

[0064] In some embodiments, the system further includes a first process gas supply fluidly coupled to the remote plasma source to deliver a process gas to the remote plasma source, the process gas including nitrogen fluoride, tetrafluoromethane, trifluoromethane, difluoromethane, fluoromethane, sulfur hexafluoride, octafluoropropane, octafluorocyclobutane, hexafluorocyclobutene, 1,2,3,3,4-pentafluorocyclobuten-4-yl radical, fluorine, or a mixture thereof.

[0065] In some embodiments, the system further includes a second process gas supply fluidly coupled to the process chamber and configured to deliver a thermal etchant into the process chamber, the thermal etchant including hydrogen bromide, hydrogen chloride, boron trichloride, or a mixture thereof.

[0066] In some embodiments, the second process gas supply is fluidly coupled to a remote plasma source.

[0067] In some embodiments, the system further includes a vaporization point fluidly coupled to the process chamber to deliver a thermal etchant into the process chamber, the thermal etchant including boron bromide, phosphorus trichloride, carbon tetrachloride, nitrogen trichloride, or a mixture thereof.

[0068] In some embodiments, (a) includes co-flowing the remote plasma and the thermal etchant into the process chamber.

[0069] In some embodiments, (a) includes first introducing a remote plasma into the process chamber and then introducing a thermal etchant a second time.

[0070] In some embodiments, the controller is further configured to (c) control the chamber temperature to between about 50 and about 650°C.

[0071] In some embodiments, the system further includes a vacuum pump to remove volatile reaction products from the process chamber.

[0072] In some embodiments, the controller is further configured to (d) control the chamber pressure to between about 0.5 and about 100 Torr.

[0073] In some embodiments, the controller is further configured to (e) control an etch rate of the dielectric material between about 500 and about 1,000 angstroms per minute.

[0074] Yet another aspect is a method of cleaning a process chamber. The method can include heating the process chamber to a predetermined temperature. A plasma effluent can be delivered into the process chamber from a remote plasma source through a showerhead to clean the process chamber, the remote plasma source being fluidly coupled to the process chamber through the showerhead and located upstream of the process chamber. The plasma effluent limits diffusion of gaseous contaminants from the showerhead.

[0075] In some embodiments, the plasma flow is delivered in a downward or substantially downward direction.

[0076] In some embodiments, the plasma source includes an inductively coupled plasma, a capacitively coupled plasma reactor, a microwave plasma reactor, a DC plasma reactor, or a laser-produced plasma reactor.

[0077] In some embodiments, the plasma flow has a flow rate of about 1 to about 50 liters per minute.

[0078] In some embodiments, the plasma effluent comprises an oxygen-containing species, a fluorine-containing species, and an inert gas.

[0079] In some embodiments, the gaseous pollutant comprises a metal fluoride, for example, the gaseous pollutant comprises aluminum fluoride.

[0080] In some embodiments, the predetermined temperature is in the range of about 450°C to about 650°C.

[0081] In some embodiments, the predetermined temperature is in the range of 500°C to 600°C.

[0082] In some embodiments, heating the process chamber includes heating the pedestal.

[0083] In some embodiments, the plasma effluent is delivered at a flow rate sufficient to substantially prevent gaseous contaminants from depositing on the showerhead.

[0084] In some embodiments, the method further includes providing a substrate in the process chamber. The method also includes depositing a film on the substrate prior to delivering the plasma fluence to clean the process chamber. Prior to depositing the film, the process chamber temperature is maintained at a predetermined temperature. The film is deposited at the predetermined temperature. The method also includes transferring the substrate from the process chamber after depositing the film on the substrate and prior to delivering the plasma fluence to clean the process chamber. Delivering the plasma fluence to clean the process chamber includes removing deposition by-products from the process chamber after depositing the film on the substrate.

[0085] Yet another aspect of the present disclosure relates to a method for cleaning a process chamber. The method includes heating a pedestal in the process chamber to a predetermined temperature and depositing a film on a substrate in the reaction chamber. The method also includes transferring the substrate from the process chamber and generating a plasma flow at a remote plasma source. The remote plasma source is fluidly coupled to the process chamber through a showerhead and located upstream of the process chamber. The method also includes delivering a plasma flow from the remote plasma source in a downward direction through the showerhead to clean the process chamber of deposition by-products formed in the process chamber during deposition of the film on the substrate. The plasma flow is delivered at a flow rate sufficient to substantially prevent gaseous contaminants formed in the process chamber from depositing on the showerhead.

[0086] In some embodiments, the plasma flow has a flow rate of about 1 to about 50 liters per minute.

[0087] In some embodiments, the plasma effluent comprises an oxygen-containing species, a fluorine-containing species, and an inert gas.

[0088] In some embodiments, the remote plasma source includes an inductively coupled plasma reactor, a capacitively coupled plasma reactor, a microwave plasma reactor, a DC plasma reactor, or a laser-produced plasma reactor.

[0089] In some embodiments, the gaseous pollutant comprises a metal fluoride, hi some embodiments, the gaseous pollutant comprises aluminum fluoride.

[0090] In some embodiments, the predetermined temperature is in the range of about 450° C. to about 650° C. In some embodiments, the predetermined temperature is in the range of about 500° C. to about 600° C.

[0091] In some embodiments, depositing a film on the substrate comprises depositing a silicon-based film on the substrate. Prior to and during deposition, the pedestal temperature is maintained at a predetermined temperature.

[0092] These and other features of the disclosed embodiments are described in detail below with reference to the associated drawings. [Brief description of the drawings]

[0093] [Figure 1A] FIG. 1A illustrates an example of a molybdenum precursor that can be used in deposition methods according to some embodiments.

[0094] [Figure 1B] FIG. 1B illustrates some specific examples of molybdenum precursors that can be used in methods according to some embodiments.

[0095] [Diagram 2] FIG. 2 is a process flow diagram for a method of forming a metal-containing film according to some embodiments.

[0096] [Figure 3A] FIG. 3A is a process flow diagram for a method of forming a metal-containing film according to some embodiments.

[0097] [Figure 3B] FIG. 3B illustrates an example of a timing sequence that may be used to deposit a metal-containing layer. [Figure 3C] FIG. 3C illustrates an example of a timing sequence that may be used to deposit a metal-containing layer.

[0098] [Figure 4A] FIG. 4A is a process flow diagram for a method of treating a metal-containing film according to some embodiments.

[0099] [Figure 4B] FIG. 4B is a process flow diagram for a method of treating a metal-containing film according to some embodiments.

[0100] [Diagram 5] FIG. 5 is a schematic cross-sectional view of a pMOS device structure including a layer of a substantially carbon-free metal-containing material according to some embodiments.

[0101] [Figure 6A] FIG. 6A is a schematic cross-sectional view of a semiconductor device under fabrication according to some embodiments. [Figure 6B] FIG. 6B is a schematic cross-sectional view of a semiconductor device under fabrication according to some embodiments. [Figure 6C] FIG. 6C is a schematic cross-sectional view of a semiconductor device under fabrication according to some embodiments.

[0102] [Figure 7] FIG. 7 is a schematic diagram of an apparatus suitable for depositing films according to some embodiments.

[0103] [Figure 8] FIG. 8 is a schematic diagram of a multi-station processing system according to some embodiments.

[0104] [Figure 9] FIG. 9 is a schematic diagram of a multi-station processing system according to some embodiments.

[0105] [Figure 10] FIG. 10 is a schematic side view with a cross-sectional insert of a flow mixer according to some embodiments.

[0106] [Figure 11A] FIG. 11A is a diagram of a portion of a dual plenum showerhead assembly according to some embodiments.

[0107] [Figure 11B] FIG. 11B is a diagram of a portion of a showerhead faceplate removed from a showerhead housing according to some embodiments.

[0108] [Figure 12] FIG. 12 is a flow chart of an exemplary method for cleaning internal surfaces of a process chamber according to some embodiments.

[0109] [Figure 13] FIG. 13 is a flow chart of an exemplary method for cleaning internal surfaces of a process chamber according to some embodiments.

[0110] [Figure 14] FIG. 14 is a flow chart of an exemplary method for cleaning interior surfaces of a process chamber on which a carbon- and molybdenum-containing film has been deposited according to some embodiments.

[0111] [Figure 15] FIG. 15 is a flow chart of an exemplary method for cleaning inner surfaces of a process chamber on which a carbon- and molybdenum-containing film has been deposited according to some embodiments.

[0112] [Figure 16] FIG. 16 is a schematic diagram of an exemplary processing apparatus having a remote plasma source according to some embodiments.

[0113] [Figure 17] FIG. 17 is a flow chart of an example of removing dielectric material according to some embodiments.

[0114] [Figure 18] FIG. 18 is a flow chart of an example of removing dielectric material according to some embodiments.

[0115] [Figure 19] FIG. 19 is a flow chart of an example of removing dielectric material according to some embodiments.

[0116] [Figure 20]FIG. 20 is a cross-sectional view of an exemplary process chamber using an exemplary remote plasma source in accordance with some embodiments.

[0117] [Figure 21] FIG. 21 is a cross-sectional view of one station of a multi-station processing tool using an exemplary remote plasma device in accordance with some embodiments.

[0118] [Figure 22] FIG. 22 is a flow diagram of an operation according to one exemplary embodiment.

[0119] [Diagram 23] FIG. 23 shows a scanning electron microscope (SEM) image of a portion of a ceramic coupon positioned on a showerhead after chamber cleaning with a plasma flow according to some embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0120] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the presented embodiments. The disclosed embodiments may be practiced without some or all of these specific details. In other instances, well-known process operations have not been described in detail so as not to unnecessarily obscure the disclosed embodiments. It will be understood that while the disclosed embodiments will be described in conjunction with specific embodiments, they are not intended to limit the disclosed embodiments.

[0121] definition The terms "semiconductor wafer," "wafer," "substrate," "wafer substrate," and "partially fabricated integrated circuit" may be used interchangeably. Those skilled in the art will appreciate that the term "partially fabricated integrated circuit" can refer to a semiconductor wafer at any of the many stages of integrated circuit fabrication. Wafers or substrates used in the semiconductor device industry typically have diameters of 200 mm, 300 mm, or 450 mm. Examples of wafer materials include silicon (Si), gallium arsenide (GaAs), and silicon germanium (SiGe). In addition to semiconductor wafers, other workpieces that may utilize the disclosed embodiments include various articles such as printed circuit boards, magnetic recording media, magnetic recording sensors, mirrors, optical elements, display devices, or components such as backplanes for pixelated display devices, flat panel displays, micromechanical devices, and the like. The workpieces may be of various shapes, sizes, and materials.

[0122] A "semiconductor device fabrication operation", as used herein, is an operation performed during the fabrication of a semiconductor device. Typically, the entire fabrication process includes multiple semiconductor device fabrication operations, each of which is performed in its own semiconductor fabrication tool, such as a plasma reactor, an electroplating cell, a chemical mechanical planarization tool, a wet etching tool, etc. Categories of semiconductor device fabrication operations include subtractive processes, such as etching processes and planarization processes, as well as material additive processes, such as deposition processes (e.g., physical vapor deposition (PVD), chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), plasma enhanced atomic layer deposition (PEALD), electrochemical deposition, electroless deposition). In the context of an etching process, a substrate etching process includes a process of etching a mask layer, or more generally, a process of etching any layer of material previously deposited on and / or possibly present on a substrate surface. Such an etching process can etch a stack of layers within a substrate.

[0123] In this disclosure, the terms "depositing" and "forming" are used interchangeably. Also, the terms "layer," "film," and "thin film" are used interchangeably. Those skilled in the art will understand that "forming" a "layer" at any of the many stages of integrated circuit fabrication can refer to "depositing" a "film" or "thin film" by one of a variety of film formation methods, such as CVD, PECVD, ALD, or PEALD, due to the reduction in feature sizes in semiconductor devices.

[0124] In this disclosure, the terms "cleaning," "etching," and "removing" are used interchangeably. In the context of an etching process, those skilled in the art will agree that etching material from the interior surfaces of a process chamber is equivalent to "cleaning" or "removing" material from the interior surfaces of the process chamber, thereby leaving the interior surfaces free of material.

[0125] In this disclosure, the term "remote plasma cleaning" refers to removing or etching a layer from an interior surface of a process chamber using plasma activated species generated from a remote plasma source. The plasma activated species may include fluorine-containing species and may react aggressively with the layer to form non-volatile or volatile reaction products. Nitrogen trifluoride (NF3) or fluorine (F2) may be the process gas supplied to the remote plasma source to generate the fluorine-containing species. The layer may include a metal, a metal alloy, an oxide, a doped or undoped nitride, a doped or undoped carbide, or a mixture thereof.

[0126] In this disclosure, the term "thermal etching" refers to the use of gas phase reagents to react with the substrate surface and chemically and / or thermally etch material from the substrate surface. Thermal etching may also be referred to as "chemical etching." In some cases, thermal etching does not use plasma or radicals. In some cases, the etch rate for thermal etching is temperature sensitive and proceeds faster at higher temperatures.

[0127] Methods are provided for depositing metal-containing films, including molybdenum-containing and tungsten-containing films, on semiconductor substrates. In some embodiments, the films are substantially carbon-free. These methods can be used, for example, to deposit blanket metal-containing layers on planar substrates, to deposit conformal metal-containing layers on substrates having one or more recessed or protruding features, and to fill recessed features with metal-containing materials. In some embodiments, methods are provided for forming metal-containing layers as liner or diffusion barrier layers on semiconductor substrates. In some embodiments, methods are provided for forming metal-containing layers substantially as electrode layers in devices such as pMOS devices. In some embodiments, the metal-containing layers may be used as hard masks.

[0128] The method can be used to deposit a variety of molybdenum- and tungsten-containing materials, including, but not limited to, molybdenum metal (Mo), molybdenum nitride (MoN), molybdenum boride (MoB), molybdenum silicide (MoSi), and molybdenum oxynitride (MoON), tungsten metal (W), tungsten nitride (WN), tungsten boride (WB), tungsten silicide (WSi), and tungsten oxynitride (WON), the stoichiometry of these compounds can vary and the listed formulas do not indicate stoichiometry. For example, MoN can, in various embodiments, contain about 10 to about 70 atomic % nitrogen, with the remainder being molybdenum.

[0129] The term "substantially carbon-free" refers to a material having a carbon content of less than about 5 atomic %, where hydrogen, if present, is excluded from the calculation. In some embodiments, substantially carbon-free films are provided that contain less than about 3 atomic % carbon, such as less than about 2 atomic % carbon.

[0130] "Metal", e.g., "metallic molybdenum" or "metallic tungsten", as used herein, refers to a material that consists essentially of a metal (e.g., Mo or W). Other elements (e.g., B, Si, N, or O) may be present in the metal in small amounts (e.g., less than about 15 atomic %, or less than about 10% total content, hydrogen not being included in the calculation).

[0131] Molybdenum nitride (MoN), molybdenum boride (MoB), molybdenum silicide (MoSi), molybdenum oxynitride (MoON), tungsten nitride (WN), tungsten boride (WB), tungsten silicide (WSi), tungsten oxynitride (WON) refer to materials consisting essentially of the recited elements, and the stoichiometry of these compounds may vary and is not determined by the recited formula (e.g., MoN does not necessarily indicate a 1:1 Mo:N stoichiometry). Other elements (e.g., boron, silicon, nitrogen, phosphorus, etc.) may be present in these compounds in small amounts, e.g., less than about 10%, about 5%, or about 1% of the atoms, and hydrogen is excluded from the calculation.

[0132] The term "semiconductor substrate," as used herein, refers to a substrate at any stage of semiconductor device fabrication that includes semiconductor material anywhere within its structure. It is understood that the semiconductor material in a semiconductor substrate need not be exposed. A semiconductor wafer having multiple layers of other materials (e.g., dielectrics) covering the semiconductor material is an example of a semiconductor substrate. The following detailed description assumes that the disclosed embodiments are implemented on a semiconductor wafer, e.g., a 200 mm, 300 mm, or 450 mm semiconductor wafer. However, the disclosed embodiments are not so limited. Workpieces may be of various shapes, sizes, and materials. In addition to semiconductor wafers, other workpieces that may utilize the disclosed embodiments include various articles such as printed circuit boards.

[0133] The term "about" as used in reference to numerical values ​​includes a range of ±10% of the recited numerical value, unless otherwise specified.

[0134] The term "alkyl" as used herein refers to a saturated substituent containing only carbon and hydrogen atoms. Alkyl includes straight chain, branched, and cyclic groups. Examples of straight chain alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, n-butyl, and the like. Examples of branched alkyl groups include, but are not limited to, isopropyl, isobutyl, sec-butyl, and t-butyl. Examples of cycloalkyl include, but are not limited to, cyclopropyl, cyclopentyl, cyclohexyl, and the like.

[0135] The term "fluoroalkyl" as used herein refers to an alkyl group that contains one or more fluorine substituents. In some embodiments, the fluoroalkyl contains only fluorine substituents, such as CF3, C2F5, C3F7, etc. The fluoroalkyl may be linear, branched, and cyclic.

[0136] The term "alkylsilyl" as used herein refers to a SiR group, where at least one R is an alkyl, and each R is independently selected from H and alkyl. Alkylsilyl includes mono-, bis-, and tris-alkylsilyl. Examples of alkylsilyl include trimethylsilyl, dimethylsilyl, methylsilyl, triethylsilyl, diethylsilyl, and ethylsilyl.

[0137] The term "alkylamino," as used herein, refers to the group NR, where at least one R is alkyl and each R is independently selected from H and alkyl. Examples of alkylamino substituents include dimethylamino and diethylamino substituents.

[0138] The term "alkoxy" refers to the group OR, where R is alkyl. Examples of alkoxy groups include methoxy, ethoxy, and propoxy groups.

[0139] The term "independently selected," when referring to the selection of R substituents in a molecule that contains multiple R groups, means that the selections of R substituents at different atoms of the molecule are independent, and also that the selection of R substituents at an atom that has multiple R substituents is independent.

[0140] The term "metal organic precursor," as used herein, refers to a metal-containing compound that includes at least one carbon-containing ligand, wherein the compound does not contain a metal-carbon bond.

[0141] Deposition of metal-containing films One aspect of the present disclosure relates to the deposition of metal-containing films. In the following description, this is described primarily by way of example with reference to molybdenum-containing precursors and films, with the understanding that the general description and principles also apply to tungsten-containing precursors and films.

[0142] Deposition of molybdenum- and tungsten-containing films with desirable properties on semiconductor substrates has resulted in several issues that prevent the integration of these films in many device fabrication process flows. Specifically, the use of halide-containing molybdenum and tungsten CVD and ALD precursors can cause inadvertent etching of the substrate. Metal-organic and organometallic precursors can eliminate the integration problems in semiconductor processing caused by halide-containing precursors, but the use of carbon-containing precursors often results in the incorporation of large amounts of carbon into the formed films, since molybdenum and tungsten form very stable carbide phases. Carbon-containing films are undesirable for many applications, since the presence of carbon can increase the resistivity of the film and decrease the work function of the film.

[0143] Methods are provided for the deposition of substantially carbon-free molybdenum- and tungsten-containing films. These methods are useful for depositing molybdenum- and tungsten-containing materials, such as nitrides, borides, silicides, oxynitrides, and combinations thereof. Some materials deposited by these methods are used as gate electrode materials in MOSFETs (metal oxide semiconductor field effect transistors). Because carbon negatively impacts the effective work function of early transition metal films, these methods are advantageous for resulting in films with high work functions (e.g., greater than about 5 eV) suitable for pMOS structures. Some materials deposited by these methods are also useful as ultrathin low resistivity liner and / or barrier materials. In some embodiments, these methods are carried out in an integrated multi-chamber apparatus, including, for example, a deposition chamber and a plasma treatment chamber, and the substantially carbon-free film is deposited by CVD or ALD in the absence of plasma in the deposition chamber and treated with plasma in the plasma treatment chamber. Plasma treatment can be used to adjust the film composition, densify the formed film, and / or adjust the effective work function of the formed material.

[0144] The provided methods utilize halide-free molybdenum- or tungsten-containing metal organic compounds as CVD or ALD precursors, where the metal organic compounds do not contain metal-carbon (molybdenum-carbon or tungsten-carbon) bonds and do not contain carbonyl (CO) ligands. Furthermore, in some embodiments, the precursors do not contain beta hydrogen atoms. The deposition, in some embodiments, is carried out by reacting the precursor with a reactant in the absence of a plasma. In some embodiments, the reaction is carried out in the absence of a plasma at a temperature of less than about 450° C., e.g., less than about 420° C. By careful selection of the precursors, it is advantageously possible to avoid substantial incorporation of carbon into the formed film, and films can be formed with a carbon content of less than about 5 atomic %, e.g., less than about 3 atomic %. This result is unexpected since the metal organic precursors contain carbon, and it may be expected that due to the high affinity of molybdenum and tungsten for carbon, a high level of carbon incorporation into the film would necessarily occur. However, it has been discovered that carbon incorporation into the film can be avoided if the metal in the precursor does not form a direct bond with carbon, and if the precursor does not contain a carbonyl ligand, especially if a plasma is not used during the deposition reaction. Another factor that can significantly reduce carbon incorporation into the film is the absence of beta hydrogen in the ligands of the metal-containing precursor. It is believed that beta hydrogen may trigger a low-energy reaction pathway that leads to carbon incorporation into the film even at low temperature deposition conditions. The absence of beta hydrogen may stabilize the ligand against decomposition, allowing the ligand to be removed intact during subsequent reactant gas exposure.

[0145] While thermal (non-plasma) deposition is used in many embodiments, the methods described herein can also be used with plasma-based deposition. In plasma-enhanced CVD (PECVD), a plasma can be generated or delivered to the process chamber to increase the reaction rate of reagents, allowing deposition at lower temperatures. Plasma species can also be used to modify the resulting film properties. A plasma-enhanced ALD (PEALD) cycle can include the following operations: (i) precursor delivery / adsorption, (ii) precursor purging from the chamber, (iii) second reactant delivery and plasma ignition, and (iv) by-product purging from the chamber.

[0146] In some embodiments, a metal-containing precursor, as used herein, includes a metal (e.g., molybdenum or tungsten) that forms bonds only with elements selected from the group consisting of N, O, and S. In some embodiments, the precursor preferably does not include a beta hydrogen atom. For example, in some embodiments, the precursor includes a carbon bonded to three alkyl groups at the beta position. In some embodiments, the precursor does not include a metal-oxygen double bond (M=O).

[0147] In some embodiments, precursors that can be used for deposition include halide-free molybdenum and tungsten complexes having at least one monodentate ligand such as an amine, nitrile, imide, nitride, alkoxide, or thiolate, or having a multidentate ligand that bonds to the metal through an N, O, or S atom. The ligands preferably do not contain a β-hydrogen atom.

[0148] Examples of suitable molybdenum-containing precursors 1-16 are shown in FIG. 1A, where each L is a carbon-containing ligand that does not form a metal-carbon bond, m is an integer between 1 and 4, and n is an integer between 1 and 4. Each R and R1 is independently selected from the group consisting of alkyl, fluoroalkyl, and alkylsilyl. In some embodiments, each R1 is selected so as not to provide a beta hydrogen atom. Examples of such R1 substituents include t-butyl and trialkylsilyl substituents. It is noted that in some embodiments, R substituents at O ​​and S atoms may provide a beta hydrogen atom, since at these positions, the beta hydrogen is not easily eliminated and is not expected to cause carbon contamination of the resulting film. Additionally, in compounds 7, 8, and 14, the beta hydrogen at the alkyl-substituted carbon atom adjacent to the anionic nitrogen is also stabilized, and these stabilized compounds are also suitable for deposition of the resulting film.

[0149] In some embodiments, R and R1 do not both provide a beta hydrogen atom. In some embodiments, the precursor does not include a beta hydrogen atom. For example, in some embodiments, the precursor is any of compounds 1, 2, 3, 4, 5, 6, 15, and 16, and each of R, R1, and L does not provide a beta hydrogen atom.

[0150] More specific examples of molybdenum-containing precursors are shown in FIG. 1B, illustrating structures 17-20. It can be seen that molybdenum forms bonds only with N and O atoms, and the precursors do not contain hydrogen atoms in the beta position. The precursors can be synthesized by reacting a molybdenum starting material, such as a halide-containing molybdenum starting material, with a deprotonated ligand. Exemplary synthetic routes are described in U.S. Patent Application Publication No. 2018 / 0355484, the disclosure of which is incorporated herein by reference for purposes of describing the synthetic routes.

[0151] The precursors used for deposition are easily vaporized and stable at the target temperature and pressure. For example, in some embodiments, the precursors are used in deposition reactions at temperatures below about 450° C., such as below about 420° C. To maintain adequate volatility, in many embodiments described herein, precursors are selected that have a molecular weight below about 450 g / mol, such as below about 400 g / mol.

[0152] Substantially carbon-free molybdenum- and tungsten-containing materials can be deposited by a variety of deposition methods, such as CVD and ALD, using the precursors described herein. An exemplary method for the deposition of a molybdenum- or tungsten-containing layer is illustrated by the process flow diagram shown in FIG. 2. The process begins in 201 by introducing a halide-free molybdenum- or tungsten-containing precursor into a process chamber housing a semiconductor substrate. The precursor does not contain metal-carbon bonds and preferably does not contain beta hydrogen atoms. The precursor can be introduced in vaporized form into a flow of an inert gas, such as argon, helium, or nitrogen (N2). In operation 203 (which can occur before, after, or during the introduction of the molybdenum-containing precursor 201), a reactant is introduced into the process chamber housing the substrate. In some embodiments, the introduction of the metal-containing precursor and the reactant are sequential. The reactant chemistry depends on the chemistry of the target molybdenum- or tungsten-containing film. For example, for deposition of metals (Mo or W), the second reactant is typically a reducing reactant (e.g., H2). Deposition of metal nitrides can be carried out using nitrogen-containing reactants (e.g., NH3 or N2H4). In some embodiments, metal nitrides are deposited using H2 as the reactant, with the necessary nitrogen being provided by a ligand. Deposition of metal borides can be carried out using boron-containing reactants (e.g., B2H6). Metal silicides can be formed using silicon-containing reactants (e.g., SiH4 or Si2H6).

[0153] In some embodiments, the precursor and reactant are allowed to mix within the body of the process chamber. In other embodiments, after the metal-containing precursor is introduced and adsorbed on the surface of the substrate, the process chamber is purged and / or evacuated with an inert gas to remove unadsorbed precursor from the process chamber. In some embodiments, the layer of precursor on the substrate is adsorption limited. In other embodiments, a thicker layer of precursor can be formed on the surface of the substrate before purging and / or evacuating the process chamber. Note that when the precursor and reactant are introduced sequentially, the order of introduction of the precursor and reactant may be reversed. In some embodiments, the reactant is introduced first and allowed to adsorb on the surface of the substrate. The process chamber is then purged and / or evacuated to remove the second reactant from the volume of the process chamber, after which the precursor is introduced.

[0154] Referring to operation 205, the precursor reacts with the reactant to form a layer of substantially carbon-free molybdenum-containing material on the substrate, the reaction occurring on the surface of the substrate and / or in the body of the processing chamber, preferably in the absence of plasma. For example, in a CVD process, the precursor and the reactant may be simultaneously introduced into the body of the processing chamber, where the reaction occurs sequentially on the body or surface of the processing chamber. In an ALD process, the reaction occurs only on the surface, and is limited by the amount of adsorbed material on the surface (by the amount of precursor and / or the amount of adsorbed reactant). The temperature during the reaction process may be, for example, about 20 to about 600° C. In some embodiments, low temperature deposition at about 450° C. or less, such as about 420° C. or less, for example, about 200 to about 400° C., is performed, which is particularly advantageous for deposition of substantially carbon-free films. The pressure in the process chamber may be in the range of about 0.1 to about 100 Torr, for example, in thermal ALD, in the range of about 1 to about 60 Torr, for example, about 10 Torr.

[0155] After the reaction is complete, the formed molybdenum- or tungsten-containing layer can be optionally treated with a second reactant to modify the layer, as shown in operation 207. The treatment may be performed to adjust the properties of the layer, such as densifying the layer, modifying the composition or electrical properties of the layer, reducing the resistivity of the layer, etc. The treatment is plasma-assisted in some embodiments. For example, the substrate can be treated with a direct plasma (formed in the compartment housing the substrate) or a remote plasma (formed away from the substrate and introduced into the compartment housing the substrate). The use of a remote plasma is preferred in some cases because it reduces damage to the substrate. In one preferred embodiment, the substantially carbon-free molybdenum- or tungsten-containing layer is deposited in the absence of a plasma. The substrate is then transferred to a plasma treatment process chamber without exposure to an ambient atmosphere, where the substrate is treated with a plasma treatment reactant. The choice of plasma treatment reactant depends on the desired properties of the final layer. The substrate may be treated with, for example, plasma activated H2, NH3, N2, BH3, SiH4, Ar, He, and mixtures thereof.

[0156] An example of a surface-based deposition process for forming a molybdenum- or tungsten-containing film on a substrate is illustrated by the process flow diagram shown in FIG. 3A. In operation 301, a layer of metal-containing precursor and / or reactant is formed on the surface of the substrate. In some embodiments, the layer is an adsorption-limited layer. Then, in operation 303, the process chamber is purged and / or evacuated. This step ensures that the precursor and / or reactant is only on the surface of the substrate and not within the volume of the process chamber. Then, in 305, the precursor reacts with the reactant on the surface of the substrate. For example, if only the metal-containing precursor is adsorbed on the surface of the substrate in 301, the reactant can be introduced into the process chamber and allowed to react with the precursor on the surface. If both the metal-containing precursor layer and the reactant layer are formed on the surface of the substrate in 301, the process conditions can be adjusted (e.g., using an increased temperature) to activate the reaction in 313. Next, at 307, the process chamber is purged and / or evacuated, and at 309, operations 301-307 are repeated to form more metal-containing material. In some embodiments, each cycle of operations 301-307 deposits, on average, about 0.1 to about 5 Å of metal-containing material. In some embodiments, 1 to 100 cycles, such as 2 to 100 cycles, are performed. For example, 1 to 20 cycles, such as 2 to 20 cycles, can be performed. Substantially carbon-free molybdenum-containing and tungsten-containing layers having thicknesses of about 5 to about 500 Å, such as 5 to about 50 Å, can be formed with a high level of control over the layer thickness. Using this method, it is possible to form conformal layers with excellent step coverage.

[0157] 3B and 3C show examples of timing sequences of reactants that can be used to deposit a metal-containing film. In FIG. 3B, the flow of metal-containing precursor alternates with the reactant. In this example, the reactant is H2. An inert gas can be flowed along with the metal-containing precursor. In this example, the metal-containing precursor is loaded to a certain loading volume before being introduced to the station containing the substrate on which the film is to be deposited. The exposure to the metal-containing precursor is referred to as dosing in FIG. 3B. The inert gas may then purge the station. This is followed by exposure to H2 and then purging. The cycle may then be repeated. The heights and lengths of the various operations are provided for illustrative purposes and do not reflect actual flow rates or times. In some embodiments, the H2 conversion may be significantly longer than the dosing, for example at least 2, 3, 4, or 5 times longer.

[0158] In some embodiments, the process is carried out with co-flow of a reactant such as hydrogen (H2) during dosing. Figure 3C shows an example where H2 is flowed throughout the process, including during dosing as well as the subsequent portion of the cycle where no metal-containing precursor flows into the station. According to various embodiments, an inert gas may or may not be flowed during all or part of the cycle.

[0159] The timing sequence shown in FIG. 3C may be used in some embodiments where H2 or other reactants do not react with the gas phase metal precursor. For example, H2 does not react with certain gas phase halide-free metal organic precursors such as bis(tert-butylimido)bis(tert-butoxy)molybdenum, but does react with the deposited film. Throughput can be increased by co-flowing H2 or other reactants with the metal-containing precursor. Additionally, compositional control can be enhanced with a longer portion of the cycle used to reduce the deposited film and / or control the oxygen, nitrogen, and / or carbon content in the film. As described herein, this can be used to modulate film properties including density, etch rate, resistivity, or effective work function.

[0160] In some embodiments, H2 or other reactants are flowed at high pressure, e.g., at least 10 Torr, at least 20 Torr, at least 50 Torr, at least 100 Torr, at least 200 Torr, or at least 250 Torr. Example pressures are 10 to 300 Torr, including the end point. This can be done for both non-cocurrent (e.g., FIG. 3B) or cocurrent (e.g., FIG. 3C) embodiments. High pressure and / or long conversion operation can promote reduction of the deposited film.

[0161] In some embodiments, the as-deposited substantially carbon-free molybdenum- and tungsten-containing films are treated with a second reactant to modify the film properties, such as density, resistivity, or effective work function.

[0162] FIG. 4A shows a process flow diagram for one example of film modification. The process begins in 401 by reacting a molybdenum-containing precursor with a reactant to form a substantially carbon-free molybdenum-containing film on a substrate in the absence of plasma. For example, a MoN layer can be formed using several cycles of reacting a halide-free metalorganic molybdenum-containing precursor with NH3 or H2 in the absence of plasma on the surface of the substrate. Next, in operation 403, the film is treated with a plasma-activated nitrogen-containing reactant to increase the nitrogen content in the film. For example, a MoN film can be treated with a plasma formed in a process gas containing N2 to increase the nitrogen content in the MoN layer. In some embodiments, the nitrogen content is increased by at least 5%, such as at least 10%, by such treatment. The increase in nitrogen content in the MoN layer is associated with an increase in work function. In some embodiments, the increase in work function from this treatment is at least 30 meV, such as from about 50 to about 200 meV. In some embodiments, the resulting MoN material after processing has a nitrogen content of at least 25 atomic % and a work function of at least about 5.0 eV, such as at least about 5.2 eV.

[0163] Another example of post-treatment is illustrated by the process diagram shown in FIG. 4B. In this example, the process begins by reacting a molybdenum-containing precursor with a reactant at 411 to form a substantially carbon-free molybdenum-containing layer, as in FIG. 4A. The formed layer is then treated with a plasma-activated hydrogen-containing reactant at 413 to reduce the resistivity of the layer. For example, the substantially carbon-free molybdenum nitride layer may be treated with a plasma formed in a process gas containing H2, resulting in a significant reduction in the resistivity of the film. In some embodiments, the resistivity can be reduced by at least 20%, such as at least 50%, or even at least 80% by this treatment. In some embodiments, the H2 plasma treatment reduces the resistivity of the film by at least 2, 3, or 5 times. In some embodiments, after the H2 plasma treatment, a film having a resistivity of less than about 1,000 μΩ·cm, such as less than about 800 μΩ·cm, is obtained. In some embodiments, a plasma treatment (e.g., a plasma treatment using a hydrogen-containing reactant such as H2) is further used to densify the as-deposited film. For example, the density of the film can be increased by at least 20%, such as at least 40%, by H2 plasma post-treatment.

[0164] The substantially carbon-free molybdenum- and tungsten-containing films provided can be deposited on a variety of surfaces, including on metals (e.g., copper, nickel, cobalt, tungsten, etc.), dielectrics (e.g., silicon oxide-based dielectrics, silicon nitride, silicon carbide, metal oxides, metal nitrides, etc.), and amorphous and crystalline silicon. In some embodiments, the films are deposited as liner or diffusion barrier layers.

[0165] In one embodiment, the provided substantially carbon-free metal-containing film is used as a MOSFET gate electrode material. In one example, the provided film is integrated into a pMOS device structure. A schematic cross-sectional view of a pMOS device is shown in FIG. 5. The device (e.g., a transistor) includes a semiconductor layer 501, a source region 501, a drain region 503, and a gate dielectric layer 505 formed on the semiconductor layer 501 and defining a channel region 515 in the semiconductor layer 501 between the source region 501 and the drain region 503. The semiconductor layer 501 includes a semiconductor material such as silicon (Si), germanium (Ge), or silicon germanium (SiGe). The gate dielectric layer 505 includes a high-k dielectric having a dielectric constant greater than about 3.9 in one embodiment. For example, the gate dielectric layer 505 can include a high-k material such as HfO, HfSiO, HfSiON, etc. The gate dielectric layer is typically very thin, for example, about 10 to about 15 Å thick. Layers 509, 511, and 513 are disposed on gate dielectric layer 505 and collectively form a gate electrode. Layer 509 is an optional capping layer formed directly on and in contact with gate dielectric layer 505. Capping layer 509, in some embodiments, comprises TiN, TaN, and / or WN and has a thickness of about 10 to about 20 Å. Layer 511 above capping layer 509 is referred to as a work function metal-containing layer. Layer 511 comprises a substantially carbon-free molybdenum-containing or tungsten-containing material provided herein, the material having a high work function, such as a work function greater than about 4.9 eV, greater than about 5.0 eV, or greater than about 5.1 eV. In some embodiments, layer 511 is a substantially carbon-free MoN layer having an effective work function greater than about 5.0. The substantially carbon-free layer is deposited by the ALD or CVD methods described herein and, in some embodiments, is further treated with a plasma treatment reactant to increase its work function. For example, in some embodiments, the as-deposited substantially carbon-free molybdenum- or tungsten-containing material is treated with a plasma-activated nitrogen-containing reactant (e.g., N2) to increase the nitrogen content and work function of the formed layer.Layer 511 has a thickness of about 5 to about 50 Å, or about 5 to about 15 Å, in some embodiments. In one implementation, work function metal-containing layer 511 has a thickness of about 30 Å. In some embodiments, substantially carbon-free metal-containing layer 511 is deposited directly on capping layer 509. If capping layer 509 is not present, layer 511 may be deposited directly on gate dielectric layer 507. Finally, the device may optionally include one or more conductive layers 513 formed on substantially carbon-free metal-containing layer 511. In some embodiments, conductive layer 513 includes one or more of TiAl, TiAlC, TiAlON, and / or a conductive metal fill, such as Mo, Co, or W. The device shown in FIG. 5 is a schematic of a partially fabricated device and does not show contacts formed to the source and drain regions, which may be formed after formation of the electrode layers.

[0166] The provided substantially carbon-free molybdenum-containing and tungsten-containing layers can be used in planar pMOS devices, FinFET pMOS devices, or gate-all-around (GAA) pMOS devices. Films having a work function of greater than 5.0 eV, for example, about 5.0 to about 5.5 eV, can be obtained.

[0167] In another application, the substantially carbon-free film is deposited as a diffusion barrier layer on a substrate that includes recessed features such as vias and trenches. Schematic cross-sectional views of an exemplary substrate during fabrication are shown in FIGS. 6A-6B. With reference to FIG. 6A, a substrate is provided that includes a dielectric layer 601, which may be a silicon oxide-based interlayer dielectric, e.g., a low-k dielectric, in which a recessed feature 603 is formed. With reference to FIG. 6B, a substantially carbon-free molybdenum- or tungsten-containing film 605 is conformally deposited on top of the dielectric 601, the film lining the recessed feature. The conformal film is preferably deposited by ALD using precursors described herein. In some embodiments, the film 605 is deposited directly on the dielectric. In other embodiments, one or more additional layers, such as an adhesion layer, may be formed on the dielectric before the film 605 is deposited. Next, with reference to FIG. 6C, the recessed feature 603 is filled with a metal 607, such as copper or cobalt. Copper or cobalt may be deposited, for example, by electrodeposition onto a thin conformal metal seed layer (not shown). The structure formed includes a thin layer of a substantially carbon-free molybdenum- or tungsten-containing layer positioned between a dielectric layer and a metal-filled via or trench. In some embodiments, film 605 has a thickness of about 5 to about 50 Å, such as about 10 to about 30 Å. In some embodiments, film 605 is a diffusion barrier layer that prevents diffusion of a metal, such as copper, into the dielectric. Examples of suitable diffusion barrier materials include MoN and WN. In some embodiments, film 605 is an adhesion layer that may promote adhesion of a conventional diffusion barrier layer (e.g., TaN, TiN) to a conductive seed layer. Examples of suitable adhesion layer materials include Mo, and MoN with a relatively low nitrogen content. In many embodiments, film 605 is preferably a low resistivity film, such as a film having a resistivity of less than about 1000 μΩ·cm, such as less than about 500 μΩ·cm. In some embodiments, these films are formed using a plasma post-treatment of the as-deposited substantially carbon-free film, where the post-treatment reduces the resistivity of the as-deposited film.For example, in some embodiments, the deposited film (e.g., a MoN or WN film) is post-treated with a plasma formed in a hydrogen-containing gas (e.g., H2), as described with reference to FIG. 4B.

[0168] It should be noted that although the description provided herein uses molybdenum deposition as an example, tungsten-containing layers can be deposited using similar precursors and conditions. For example, a tungsten-containing precursor (with molybdenum substituted for tungsten) having the same structure as that shown in Figures 1A and 1B can be used.

[0169] Experimental Example Example 1. Substantially carbon-free MoN films were deposited on SiO2 substrates using bis(tert-butylimido)bis(tert-butoxy)molybdenum (compound 19), shown in FIG. 1B, as the molybdenum-containing precursor. The substrate was exposed to precursor 19 in an ALD process chamber. The process chamber was then purged to remove precursor not bound to the surface, and the substrate was contacted with reactants (NH3, H2, or combinations of NH3 and H2, in mixtures or sequentially) to react the precursor on the surface of the substrate. The process chamber was purged and the dosing of precursor and reactant was repeated. From 1 to 500 ALD cycles were used. Deposition was carried out in the absence of plasma at temperatures of about 300 to about 400 °C.

[0170] Compositional analysis of the deposited MoN films by both X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) indicated a carbon content of 0.2–2 atomic %. The resistivity of the films was 500–4,000 μΩ·cm for film thicknesses of 2–10 nm.

[0171] The 2 nm thick films were subjected to H2 plasma treatment for 60 seconds. The films were treated at 400 °C using a remotely generated plasma (13.56 MHz, 2 kW) in a process gas containing H2. The resulting 1 nm films had resistivity of about 600 μΩ·cm as measured by TEM, indicating a six-fold reduction in resistivity compared to the initial resistivity of 3600 μΩ·cm for the as-deposited films.

[0172] Example 2 (Comparative). It was demonstrated that substantial carbon incorporation occurs when a molybdenum precursor is treated with a reactant in a plasma. MoC films were deposited on SiO2 substrates using bis(tert-butylimido)bis(tert-butoxy)molybdenum (compound 19) shown in FIG. 1B as the molybdenum-containing precursor. The substrate was exposed to precursor 19 in an ALD process chamber. The process chamber was then purged to remove precursors not bound to the surface, and the substrate was contacted with a plasma formed in H2 to react the precursors on the surface of the substrate. The process chamber was purged and the precursor and reactant dosages were repeated. 200 ALD cycles were used. Deposition was carried out at a temperature of 250°C. Compositional analysis of a 15 nm film by X-ray photoelectron spectroscopy showed 58 atomic % Mo and 41 atomic % C. It is believed that the high energy plasma reactants induce uncontrolled decomposition of the organic ligands, which allows for the facile formation of highly thermodynamically stable Mo carbide films. Therefore, it is difficult to achieve substantially carbon-free metallic Mo-containing films using plasma reactants.

[0173] Example 3. Plasma treatment with a mixture of N2 and argon was performed on a 3 nm substantially carbon-free MoN film at 400°C for 150 seconds. The plasma was remotely generated with 3 kW of power. MOS capacitors were fabricated and the effective work function was obtained by extrapolating a plot of flat band voltage versus effective oxide thickness to zero. The plasma treated film showed an increase in effective work function of about 0.08 eV compared to the untreated film. Separate experiments to determine compositional changes due to plasma treatment showed that the nitrogen content was about 10% higher after plasma treatment.

[0174] Device The deposition methods described herein can be carried out in a variety of apparatus. A suitable apparatus includes a process chamber having one or more inlets for introducing reactants, a substrate holder within the process chamber configured to hold the substrate in position during deposition, and optionally a plasma generating mechanism configured to generate a plasma in the process gases. The apparatus can include a controller having program instructions for performing any of the method steps described herein.

[0175] For example, in some embodiments, an apparatus includes a controller having program instructions including instructions for introducing a molybdenum or tungsten precursor into a process chamber, the precursor being any of the precursors described herein, and causing a reaction between the precursor and a reactant to form a layer of substantially carbon-free molybdenum- or tungsten-containing material on the substrate. The controller can include program instructions for performing any of the methods described herein.

[0176] An example of a deposition apparatus suitable for depositing a molybdenum-containing film using the provided methods is shown in FIG. 7. FIG. 7 illustrates generally one embodiment of a process station 700 that may be used to deposit materials using ALD and / or CVD, both of which may be optionally plasma enhanced. It should be noted that in many embodiments, plasma enhancement of the deposition reaction is avoided to prevent carbon incorporation into the film. For simplicity, the process station 700 is illustrated as a stand-alone process station having a process chamber body 702 for maintaining a low pressure environment. However, it will be appreciated that multiple process stations 700 may be included in a common process tool environment. Additionally, it will be appreciated that in some embodiments, one or more hardware parameters of the process station 700 (including those described in detail below) may be programmatically adjusted by one or more computer controllers.

[0177] A reactant delivery system 701 delivers process gases to a distribution showerhead 706 of the process station 700. The reactant delivery system 701 includes a mixing vessel 704 for blending and / or conditioning the process gases delivered to the showerhead 706. One or more mixing vessel inlet valves 720 can control the introduction of process gases to the mixing vessel 704. Similarly, a showerhead inlet valve 705 can control the introduction of process gases to the showerhead 706.

[0178] Some metal precursors may be stored in solid or liquid form before being vaporized and then delivered to the process station. For example, the embodiment of FIG. 7 includes a vaporization point 703 for vaporizing the solid reactants delivered to the mixing vessel 704. In some embodiments, the vaporization point 703 may be a heated vaporizer. In some embodiments, a flow of inert gas is passed over the heated solid molybdenum or tungsten precursor or bubbled through the heated liquid molybdenum or tungsten precursor under subatmospheric pressure to carry the precursor vapor to the process chamber. The precursor vapor generated from such a vaporizer may condense in the downstream delivery piping. Exposure of incompatible gases to the condensed reactants may generate small particles. These small particles may clog the piping, interfere with the operation of valves, or contaminate the substrate. Some approaches to address these issues involve cleaning and / or evacuating the delivery piping to remove residual reactants. However, cleaning the delivery piping may increase the cycle time of the process station and reduce the throughput of the process station. Thus, in some embodiments, the feed piping downstream of vaporization point 703 may be heat traced. In some examples, mixing vessel 704 may also be heat traced. In one non-limiting example, the piping downstream of vaporization point 703 has an elevated temperature profile ranging from about 100° C. to about 200° C. at mixing vessel 704.

[0179] The showerhead 706 distributes process gases toward the substrate 712. In the embodiment depicted in FIG. 7, the substrate 712 is shown positioned below the showerhead 706 and resting on a pedestal 708. It will be appreciated that the showerhead 706 may have any suitable shape and may have any suitable number and arrangement of ports for distributing process gases to the substrate 712. Although not explicitly shown, in some embodiments, the showerhead 706 is a dual plenum showerhead including at least two types of conduits, a first type of conduit dedicated to the delivery of a molybdenum-containing or tungsten-containing precursor vapor and a second type of conduit dedicated to the delivery of a reactant (e.g., H2, NH3, etc.). In these embodiments, the molybdenum-containing precursor and the reactant may not mix in the conduits prior to entering the process chamber and do not share a conduit if delivered to the chamber sequentially.

[0180] In some embodiments, a micro-volume 707 is located below the showerhead 706. Performing ALD and / or CVD processes in a micro-volume rather than the full volume of the process station can reduce exposure to reactants and cleaning or purging times (i.e., duration of cleaning or purging operations), reduce time to change process conditions (e.g., pressure, temperature, etc.), limit exposure of the process station robot to process gases, etc. Exemplary micro-volume sizes include, but are not limited to, volumes between 0.1 liters and 2 liters. This micro-volume also impacts productivity throughput. While the deposition rate per cycle is reduced, cycle time is simultaneously reduced. In some cases, the latter effect is effective enough to improve the overall throughput of the module for a given target thickness of the film.

[0181] In some embodiments, the pedestal 708 can be raised or lowered to expose the substrate 712 to the micro-volume 707 and / or to change the volume of the micro-volume 707. For example, during a substrate transfer phase, the pedestal 708 can be lowered to allow the substrate 712 to be loaded onto the pedestal 708. During a deposition process phase, the pedestal 708 can be raised to position the substrate 712 within the micro-volume 707. In some embodiments, the micro-volume 707 can completely surround the substrate 712 as well as a portion of the pedestal 708, creating a region of high flow impedance during the deposition process.

[0182] Optionally, the pedestal 708 may be lowered and / or raised during a portion of the deposition process to adjust the process pressure, reactant concentration, etc., within the micro-volume 707. In one scenario in which the process chamber body 702 remains at base pressure during the deposition process, the micro-volume 707 can be evacuated by lowering the pedestal 708. Exemplary ratios of micro-volume to process chamber volume include, but are not limited to, volume ratios of 1:700 to 1:10. It will be appreciated that in some embodiments, the height of the pedestal can be programmatically adjusted by a suitable computer controller.

[0183] While the exemplary micro-volume variations described herein refer to a height-adjustable pedestal, it will be appreciated that in some embodiments, the position of the showerhead 706 can be adjusted relative to the pedestal 708 to vary the volume of the micro-volume 707. Additionally, it will be appreciated that the vertical position of the pedestal 708 and / or the showerhead 706 may be varied by any suitable mechanism within the scope of the present disclosure. In some embodiments, the pedestal 708 may include a rotation axis for rotating the orientation of the substrate 712 in an appropriate direction. It will be appreciated that in some embodiments, one or more of these exemplary adjustments may be implemented programmatically by one or more suitable computer controllers.

[0184] Returning to the embodiment shown in FIG. 7, the showerhead 706 and pedestal 708 are in electrical communication with an RF power source 714 and a matching network 716 to power the plasma. In other embodiments, an apparatus without a plasma generator is used to deposit molybdenum-containing and tungsten-containing films using the provided methods. In some embodiments, the plasma energy can be controlled by controlling one or more of process station pressure, gas concentration, radio frequency (RF) source power, RF source frequency, and plasma power pulse timing. For example, the RF power source 714 and matching network 716 can be operated at any suitable power to form a plasma having a desired composition of radical species. Similarly, the RF power source 714 can provide RF power of any suitable frequency. In some embodiments, the RF power source 714 can be configured to control the high and low frequency RF power sources independently of one another. Exemplary low frequency RF frequencies can include, but are not limited to, frequencies between 50 kHz and 700 kHz. Exemplary high frequency RF frequencies can include, but are not limited to, frequencies between 1.8 MHz and 2.45 GHz. It will be appreciated that any suitable parameters can be adjusted discretely or continuously to provide plasma energy for surface reactions. In one non-limiting example, the plasma power can be pulsed intermittently to reduce ion bombardment at the substrate surface compared to a continuously powered plasma. In some embodiments, the plasma is used for post-treatment of the deposited substantially carbon-free film.

[0185] In some embodiments, the plasma can be monitored in-situ by one or more plasma monitors. In one scenario, the plasma power can be monitored by one or more voltage, current sensors (e.g., VI probes). In another scenario, the plasma density and / or process gas concentration may be measured by one or more optical emission spectroscopy sensors (OES). In some embodiments, one or more plasma parameters can be programmatically adjusted based on measurements from such in-situ plasma monitors. For example, OES sensors can be used in a feedback loop to provide programmatic control of the plasma power. It will be appreciated that in some embodiments, other monitors can be used to monitor the plasma and other process characteristics. Such monitors can include, but are not limited to, infrared (IR) monitors, acoustic monitors, and pressure transducers.

[0186] In some embodiments, the plasma may be controlled via input / output control (IOC) sequence instructions. In one example, instructions for setting plasma conditions for a plasma process stage may be included in a corresponding plasma activation recipe stage of a deposition process recipe. In some cases, the process recipe stages may be arranged in sequence such that all instructions for a deposition process stage are executed simultaneously with that process stage. In some embodiments, instructions for setting one or more plasma parameters may be included in a recipe stage preceding a plasma process stage. For example, a first recipe stage may include instructions for setting flow rates of an inert gas and / or a reactant gas, instructions for setting a plasma generator to a power set point, and a time delay instruction for the first recipe stage. A second subsequent recipe stage may include instructions for enabling the plasma generator, and a time delay instruction for the second recipe stage. A third recipe stage may include instructions for disabling the plasma generator, and a time delay instruction for the third recipe stage. It will be understood that these recipe stages may be further subdivided and / or repeated in any suitable manner within the scope of the present disclosure.

[0187] In some embodiments, the pedestal 708 may be temperature controlled via a heater 710. Additionally, in some embodiments, pressure control for the deposition process station 700 may be provided by a butterfly valve 718. As shown in the embodiment of FIG. 7, the butterfly valve 718 throttles the vacuum provided by a downstream vacuum pump (not shown). However, in some embodiments, pressure control of the process station 700 may also be adjusted by varying the flow rate of one or more gases introduced to the process station 700.

[0188] FIG. 8 shows a schematic diagram of one embodiment of a multi-station processing tool 800 comprising an inbound load lock 802 and an outbound load lock 804, either or both of which may comprise a remote plasma source. Such a tool may be used to process substrates using the methods provided herein. A robot 806 is configured to move a wafer from a cassette loaded via a pod 808 at atmospheric pressure to the inbound load lock 802 via an atmospheric pressure port 810. The wafer is placed by the robot 806 on a pedestal 812 of the inbound load lock 802, the atmospheric pressure port 810 is closed, and the load lock is pumped down. If the inbound load lock 802 comprises a remote plasma source, the wafer may undergo a remote plasma treatment in the load lock before being introduced to the processing chamber 814. Additionally, the wafer may also be heated in the inbound load lock 802 to remove, for example, moisture and absorbed gases. The chamber transfer port 816 to the processing chamber 814 is then opened and another robot (not shown) moves the wafer into the reactor and places it on the pedestal of the first station shown in the reactor for processing. Although the embodiment shown in Figure 8 includes a load lock, it will be understood that in some embodiments the wafer may enter the process station directly.

[0189] The illustrated processing chamber 814 includes four process stations, numbered 1 through 4 in the embodiment shown in FIG. 8. Each station includes a heating pedestal (shown at 818 for station 1) and a gas line inlet. It will be understood that in some embodiments, each process station may have a different purpose or multiple purposes. Although the illustrated processing chamber 814 includes four stations, it will be understood that a processing chamber according to the present disclosure may have any suitable number of stations. For example, in some embodiments, a processing chamber may have five or more stations, while in other embodiments, a processing chamber may have three or fewer stations.

[0190] FIG. 8 also illustrates one embodiment of a wafer handling system 890 for transferring wafers within the processing chamber 814. In some embodiments, the wafer handling system 890 can transfer wafers between various process stations and / or between process stations and load locks. It will be understood that any suitable wafer handling system may be used. Non-limiting examples include a wafer carousel and a wafer handling robot. FIG. 8 also illustrates one embodiment of a system controller 850 used to control the process conditions and hardware states of the process tool 800. The system controller 850 can include one or more memory devices 856, one or more mass storage devices 854, and one or more processors 852. The processor 852 can include a CPU or computer, analog and / or digital input / output connections, stepper motor controller boards, etc.

[0191] In some embodiments, system controller 850 controls all of the activity of process tool 800. System controller 850 executes system control software 858 that is stored in mass storage device 854, loaded into memory device 856, and executed on processor 852. System control software 858 may include instructions for controlling the timing, mixture of gases, chamber and / or station pressures, chamber and / or station temperatures, purge conditions and timing, wafer temperature, RF power levels, RF frequency, substrate, pedestal, chuck and / or susceptor positions, and other parameters of a particular process performed by process tool 800. System control software 858 may be configured in any suitable manner. For example, various process tool component subroutines or control objects may be written to control the operation of process tool components necessary to perform various process tool processes according to the disclosed methods. System control software 858 may be coded in any suitable computer readable programming language.

[0192] In some embodiments, system control software 858 may include input / output control (IOC) sequence instructions for controlling the various parameters described above. For example, each stage of an ALD process may include one or more instructions executed by system controller 850. Instructions for setting process conditions for an ALD process stage may be included in the corresponding ALD recipe stage. In some embodiments, the ALD recipe stages may be arranged in sequence such that all instructions for an ALD process stage are executed simultaneously with that process stage.

[0193] In some embodiments, other computer software and / or programs stored on the mass storage device 854 and / or memory device 856 associated with the system controller 850 may be used. Examples of programs or sections of programs for this purpose include a substrate positioning program, a process gas control program, a pressure control program, a heater control program, and a plasma control program.

[0194] The substrate positioning program may include program code for process tool components used to load the substrate onto the pedestal 818 and control the spacing between the substrate and other parts of the process tool 800.

[0195] The process gas control program may include code for controlling gas composition and flow rates to stabilize the pressure of the process station, and optionally code for flowing gas to one or more process stations prior to deposition. The process gas control program may include code for controlling gas composition and flow rates within any of the disclosed ranges. The pressure control program may include code for controlling the pressure of the process station, for example, by adjusting a throttle valve in the exhaust system of the process station, gas flow to the process station, etc. The pressure control program may include code for maintaining the pressure in the process station within any of the disclosed pressure ranges.

[0196] The heater control program may include code for controlling the current to a heating unit used to heat the substrate. Alternatively, the heater control program may control the delivery of a heat transfer gas (such as helium) to the substrate. The heater control program may include instructions for maintaining the temperature of the substrate within any of the disclosed ranges.

[0197] The plasma control program can include code for setting the RF power levels and frequencies applied to the process electrodes in one or more process stations, for example using any of the RF power levels disclosed herein. The plasma control program can also include code for controlling the duration of each plasma exposure.

[0198] In some embodiments, there may be a user interface associated with the system controller 850. The user interface may include a display screen, a graphical software display of equipment and / or process conditions, and user input devices such as a pointing device, keyboard, touch screen, microphone, etc.

[0199] In some embodiments, the parameters adjusted by the system controller 850 may relate to process conditions. Non-limiting examples include process gas composition and flow rates, temperature, pressure, plasma conditions (such as RF power levels, frequency, and exposure time), etc. These parameters may be provided to a user in the form of a recipe and may be entered using a user interface.

[0200] Signals for monitoring the process may be provided by analog and / or digital input connections of the system controller 850 from various process tool sensors. Signals for controlling the process can be output at analog and digital output connections of the process tool 800. Non-limiting examples of process tool sensors that can be monitored include mass flow controllers, pressure sensors (such as pressure gauges), thermocouples, etc. Appropriately programmed feedback and control algorithms can be used with data from these sensors to maintain process conditions.

[0201] Any suitable chamber can be used to perform the disclosed embodiments. Exemplary deposition equipment includes, but is not limited to, equipment from the Altus® family of products available from Lam Research, Fremont, Calif., or any of a variety of other commercially available processing systems. Two or more stations may perform the same function. Similarly, two or more stations may perform different functions. Each station can be designed / configured to perform a particular function / method desired.

[0202] In some embodiments, the apparatus includes a process chamber for depositing the substantially carbon-free films and another process chamber configured to treat these films with a remote plasma to densify the films, reduce their resistivity or increase their work function, In some embodiments, the apparatus is programmed or configured to transfer the substrate from the deposition process chamber to the plasma treatment process chamber without exposing the substrate to ambient atmosphere, moisture, or oxygen.

[0203] FIG. 9 is a block diagram of a processing system suitable for performing a thin film deposition process according to certain embodiments. The system 900 includes a transfer module 903. The transfer module 903 provides a clean pressurized environment to minimize the risk of contamination of the substrate during processing as it moves between various reactor modules. The transfer module 903 is fitted with two multi-station reactors 909 and 910, each capable of performing ALD and / or CVD according to certain embodiments. The reactors 909 and 910 can include multiple stations 911, 913, 915, and 917 that can perform operations sequentially or non-sequentially according to the disclosed embodiments. The stations may include a heated pedestal or substrate support, one or more gas inlets or a showerhead or distribution plate.

[0204] The transfer module 903 may be fitted with one or more single or multi-station modules 907 capable of performing plasma or chemical (non-plasma) pre-cleaning or any other process described in connection with the disclosed method. The modules 907 may be used in some cases for various processes to prepare the substrate for, for example, a deposition process. The modules 907 may also be designed / configured to perform various other processes such as etching or polishing. The system 900 also includes one or more wafer source modules 901 that store pre- and post-processed wafers. An atmospheric robot (not shown) in the atmospheric transfer chamber 919 may initially remove the wafer from the source module 901 and transfer it to the load lock 921. A wafer transfer device (typically a robot arm unit) in the transfer module 903 moves the wafer from the load lock 921 to the modules attached to the transfer module 903 and between the modules.

[0205] In various embodiments, a system controller 929 is used to control process conditions during deposition. The controller 929 typically includes one or more memory devices and one or more processors. The processor may include a CPU or computer, analog and / or digital input / output connections, stepper motor controller boards, etc.

[0206] The controller 929 can control all of the deposition apparatus activities. The system controller 929 executes system control software that includes a set of instructions for controlling the timing, mixture of gases, chamber pressure, chamber temperature, wafer temperature, radio frequency (RF) power levels, wafer chuck or pedestal position, and other parameters of a particular process. In some embodiments, other computer programs stored in memory devices associated with the controller 929 can be used.

[0207] Typically, there is a user interface associated with the controller 929. The user interface may include a display screen, a graphical software display of equipment and / or process conditions, and user input devices such as a pointing device, keyboard, touch screen, microphone, etc.

[0208] The system control logic may be configured in any suitable manner. In general, logic may be designed or configured in hardware and / or software. Instructions for controlling the drive circuitry may be hard-coded or provided as software. Instructions may be provided by "programming." Such programming is understood to include any form of logic, including hard-coded logic in digital signal processors, application specific integrated circuits, and other devices having specific algorithms implemented as hardware. Programming is also understood to include software or firmware instructions that may be executed on a general purpose processor. The system control software may be coded in any suitable computer readable programming language.

[0209] The computer program code for controlling the flow of precursors and other processes in a process sequence can be written in any conventional computer readable programming language (e.g., assembly language, C, C++, Pascal, Fortran, etc.). The compiled object code or script is executed by a processor to perform the tasks identified in the program. Also, as shown, the program code may be hard coded.

[0210] The controller parameters relate to process conditions such as, for example, process gas composition and flow rates, temperature, pressure, cooling gas pressure, substrate temperature, and chamber wall temperature. These parameters are provided to the user in the form of a recipe and can be entered utilizing a user interface. Signals for monitoring the process may be provided by analog and / or digital input connections of the system controller 929. Signals for controlling the process are output at analog and digital output connections of the deposition apparatus 900.

[0211] The system software can be designed or configured in many different ways. For example, various chamber component subroutines or control objects may be written to control the operation of chamber components necessary to perform a deposition process (and possibly other processes) according to the disclosed embodiments. Examples of programs or sections of programs for this purpose include substrate positioning code, process gas control code, pressure control code, and heater control code.

[0212] In some implementations, the controller 929 is part of a system, such a system may be part of the examples described above. Such a system may include semiconductor processing equipment, including one or more processing tools, one or more chambers, one or more processing platforms, and / or specific processing components (wafer pedestals, gas flow systems, etc.). These systems may be integrated with electronics for controlling system operations before, during, and after processing of a semiconductor wafer or substrate. Such electronics may be referred to as a "controller" and may control various components or subparts of one or more systems. The controller 929 may be programmed to control any of the processes disclosed herein depending on the processing requirements and / or type of system. Such processes may include delivery of process gases, temperature settings (e.g., heating and / or cooling), pressure settings, vacuum settings, power settings, radio frequency (RF) generator settings in some systems, RF matching circuit settings, frequency settings, flow rate settings, fluid delivery settings, position and motion settings, wafer loading and unloading from tools and other transfer tools connected or interlocked with a particular system, and / or wafer loading and unloading from load locks.

[0213] Broadly, a controller may be defined as an electronic device having various integrated circuits, logic, memory, and / or software that receive instructions, issue instructions, control operations, enable cleaning operations, enable endpoint measurements, etc. Integrated circuits may include chips in the form of firmware that store program instructions, digital signal processors (DSPs), chips defined as application specific integrated circuits (ASICs), and / or one or more microprocessors, i.e., microcontrollers, that execute program instructions (e.g., software). Program instructions may be instructions communicated to the controller in the form of various individual settings (or program files) that define operational parameters for performing a particular process on or for a semiconductor wafer or for a system. The operational parameters may, in some embodiments, be part of a recipe defined by a process engineer to accomplish one or more processing steps in the fabrication of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or wafer dies.

[0214] The controller, in some embodiments, may be part of, coupled to, or a combination of a computer that is integrated or coupled with the system or otherwise networked to the system. For example, the controller may be in the "cloud" or all or part of a fab host computer system. This allows for remote access of wafer processing. The computer may allow remote access to the system to monitor the current progress of a fabrication operation, review the history of past fabrication operations, review trends or performance criteria from multiple fabrication operations, modify parameters of a current process, set processing steps following a current process, or start a new process. In some examples, a remote computer (e.g., a server) may provide a process recipe to the system over a network. Such a network may include a local network or the Internet. The remote computer may include a user interface that allows entry or programming of parameters and / or settings, which are then communicated from the remote computer to the system. In some examples, the controller receives instructions in the form of data. Such data identifies parameters for each processing step performed during one or more operations. It should be understood that the parameters may be specific to the type of process being performed and the type of tool that the controller is configured to interface with or control. Thus, as discussed above, the controller may be distributed, for example, by having one or more individual controllers networked together and working together toward a common purpose (such as the processes and controls described herein). An example of a distributed controller for such purposes would include one or more integrated circuits on the chamber that communicate with one or more integrated circuits located remotely (e.g., at the platform level or as part of a remote computer) and coupled to control the process in the chamber.

[0215] Exemplary systems may include, but are not limited to, a plasma etch chamber or module, a deposition chamber or module, a spin rinse chamber or module, a metal plating chamber or module, a cleaning chamber or module, a bevel edge etch chamber or module, a physical vapor deposition (PVD) chamber or module, a CVD chamber or module, an ALD chamber or module, an atomic layer etch (ALE) chamber or module, an ion implantation chamber or module, a tracking chamber or module, and any other semiconductor processing system that may be associated with or used in the fabrication and / or manufacturing of semiconductor wafers.

[0216] As described above, depending on the process step or steps being performed by the tool, the controller may communicate with one or more other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, nearby tools, tools located throughout the factory, a main computer, another controller, or tools used for material transport to and from tool locations and / or load ports within a semiconductor manufacturing factory.

[0217] Flow Mixer In another aspect, a flow mixer is provided for mixing a carrier gas and a metal-containing precursor prior to delivery to a processing chamber. The described flow mixer is adapted to improve uniformity of delivery of the metal-containing precursor to the showerhead and can be used with any metal-containing precursor, including, but not limited to, the molybdenum and tungsten precursors described herein.

[0218] Examples of Mo-containing precursors for the ALD or CVD of molybdenum or molybdenum-containing materials include, in addition to the precursors mentioned above, MoF6, MoCl5, molybdenum dioxide dichloride (MoO2Cl2), molybdenum oxide tetrachloride (MoOCl4), and molybdenum hexacarbonyl (Mo(CO)6). x O x H z Other Mo oxyhalides include molybdenum oxide tetrafluoride (MoOF4), molybdenum dioxide dibromide (MoO2Br2), and molybdenum oxyiodides MoO2I and Mo4O 11 I. Organometallic precursors can also be used, with examples including Mo precursors with cyclopentadienyl ligands. Further examples include those of the formula Mo2L n where each L is independently selected from amidate, amidinate, and guanidinate ligands, and n is 2 to 5. Mo2L nThe precursors include molybdenum-molybdenum multiple bonds (such as double bonds or any multiple bond with bond order 2-5). Further examples include halide-containing heteroleptic molybdenum compounds (i.e., compounds with different types of ligands). Specific examples of such precursors are compounds that include molybdenum, at least one halide that forms a bond with the molybdenum, and at least one organic ligand with any of the elements N, O, and S, where an atom of any of these elements forms a bond with the molybdenum. Examples of suitable organic ligands that provide nitrogen or oxygen bonds include amidinates, amidates, iminopyrrolidinates, diazadienes, beta-iminoamides, alpha-iminoalkoxides, beta-aminoalkoxides, beta-diketiminates, beta-ketoiminates, beta-diketonates, amines, and pyrazolates. Examples of suitable organic ligands that provide sulfur bonds include thioethers, thiolates, dithiolenes, dithiolates, and α-iminothiolenes. These ligands can be substituted or unsubstituted. In some embodiments, these ligands include one or more substituents independently selected from the group consisting of H, alkyl, fluoroalkyl, alkylsilyl, alkylamino, and alkoxy substituents. The organic ligands can be neutral or anionic (e.g., monoanionic or dianionic), and the molybdenum can be in various oxidation states, such as +1, +2, +3, +4, +5, and +6.

[0219] Once the metal precursor vapor is delivered to the showerhead, it is typically mixed with a flow of carrier gas, such as N2, argon, helium, etc., to provide the desired concentration of precursor. This mixing is typically performed in a flow mixer with an outlet connected to the showerhead. Note that in many embodiments, the metal precursor vapor is delivered to the mixing tube with a first flow of carrier gas and then diluted with a second flow of carrier gas. For clarity, this more concentrated flow of metal-containing precursor in carrier gas is referred to as the metal precursor flow, and the flow of carrier gas without the precursor is referred to as the carrier gas flow.

[0220] One problem that may be encountered during mixing of these flows is non-uniform delivery of the metal precursor to the showerhead. For example, a peripheral region near the edge of the showerhead may receive a flow with a lower concentration of the metal precursor than a central portion of the showerhead. This may lead to non-uniform distribution of the metal precursor within the processing chamber. A flow mixer configured to improve the uniformity of the mixing of the metal precursor and the carrier gas is provided. In some embodiments, the flow mixer delivers the metal precursor such that the concentration of the metal precursor at all showerhead outlets varies by no more than 2% by volume. In a described embodiment, the flow mixer includes: (a) an outer fluid conduit comprising an inlet for introducing a carrier gas into the outer fluid conduit, a mixing zone for mixing the carrier gas with the metal-containing precursor, and an outlet for removing the carrier gas mixed with the metal-containing precursor from the outer fluid conduit; and (b) an inner fluid conduit positioned at least partially inside the outer fluid conduit, the inner fluid conduit comprising an inlet for introducing the metal-containing precursor into the inner fluid conduit and an outlet configured to release the metal-containing precursor into the outer fluid conduit, wherein a distance from the inlet of the inner fluid conduit to the inlet of the outer fluid conduit is greater than a distance from the outlet of the inner fluid conduit to the inlet of the outer fluid conduit, thereby supporting opposing flows of the carrier gas and the metal-containing precursor within the flow mixer, the distance referring to a distance in the z-direction.

[0221] The described flow mixer is shown in FIG. 10, which shows a schematic side view of the flow mixer 1001 and a partial cross-sectional view showing the inlet of the inner fluid conduit. Referring to FIG. 10, the outer fluid conduit 1003 has a generally cylindrical shape and has an inlet (not shown) for introducing a carrier gas at the top of the outer fluid conduit 1003. The inlet of the outer fluid conduit is connected to a carrier gas source. The flow of the carrier gas (not including the metal precursor) is indicated by a downward arrow 1005. The outlet 1007 of the outer fluid conduit 1003 is located opposite the inlet at the bottom of the outer fluid conduit 1003. The outlet is adapted to connect to a showerhead (not shown) and deliver a flow 1009 of the metal-containing precursor mixed with the carrier gas to the showerhead. The inner fluid conduit 1011 is (at least partially) inside the outer fluid conduit and has a portion coaxial with the outer fluid conduit 1003. The inner fluid conduit 1011 has an inlet 1013 configured to introduce a metal precursor from a metal precursor source. The metal precursor is typically flowed into the inner fluid conduit as a mixture with a carrier gas, but this flow has a metal precursor concentration higher than the target concentration for the showerhead and needs to be further diluted with carrier gas in the mixing tube. The flow of metal precursor entering the inner fluid conduit 1011 is indicated by arrow 1015. The outlet 1017 of the inner fluid conduit 1011 is configured to release the metal-containing precursor flowing upward as indicated by arrow 1019 into the outer fluid conduit 1003, where the flow of metal precursor is mixed with the flow of carrier gas. Notably, the distance 1018 from the inlet 1013 of the inner fluid conduit 1011 to the outlet 1017 of the inner fluid conduit 1013 in the z-direction (vertical direction) is less than the distance from the inlet 1013 of the inner fluid conduit 1011 to the inlet (not shown) of the outer fluid conduit 1003 located at the top of the outer fluid conduit 1003. This configuration can support opposing flows of carrier gas (indicated by downward arrow 1005) and metal-containing precursor (indicated by upward arrow 1019), resulting in more efficient mixing of the flows.

[0222] The outer fluid conduit 1003 has a mixing zone 1021 where the metal-containing precursor and carrier gas flows can mix without restriction, forming a mixed flow indicated by the downward arrow 1023. It is important to provide a mixing zone of an appropriate length because the mixing that occurs in this zone affects the uniformity of the precursor concentration in the showerhead. In some embodiments, the length of the mixing zone L1 in the z-direction is at least about 102 mm, such as at least about 127 mm. For example, for a flow of 1,000 sccm and an outer diameter of the outer tube of about 41 mm, a mixing zone of about 102 mm in length provides adequate mixing. In some embodiments, the ratio of the length L1 of the flow mixing zone in the z-direction to the inner diameter of the outer fluid conduit 1003 is at least about 2, such as at least about 3.

[0223] In some embodiments, such as the embodiment shown in FIG. 10, the outer fluid conduit 1003 further comprises a restriction zone 1025, where the mixed flow 1023 is restricted within a plurality of narrower channels located inside the outer fluid conduit 1003. For example, in some embodiments, the restriction zone comprises six narrower non-communicating channels that convey the mixed flow to the outlet 1007. The restriction zone has a length L2 (e.g., about 1 to about 5 mm) in the z-direction. The mixed flow within the restriction zone is indicated by a downward arrow 1027.

[0224] In some embodiments, the flow mixer 1001 is designed such that the outlet 1017 from the inner fluid conduit 1013 includes a flow diverter 1029 configured to divert the flow of metal-containing precursor before it mixes with the flow of carrier gas in the outer fluid conduit 1003, such that the diverted flow of metal-containing precursor retains a velocity component that opposes the velocity direction of the flow of carrier gas in the outer fluid conduit.

[0225] The flow splitter may include two parallel flow restriction plates configured to restrict the flow of the metal-containing precursor between the plates. For example, the upward flow of the metal-containing precursor may be diverted laterally to make a turn of less than 90 degrees, thereby maintaining an opposing velocity component to the downward direction of the carrier gas flow. Maintaining this opposing velocity component is a key factor for improving mixing efficiency. In some embodiments, the flow splitter 1029 includes a delivery tee with multiple (e.g., six) equally spaced radial openings.

[0226] In some embodiments, the ratio of the inner diameter of the outer fluid conduit to the inner diameter of the inner fluid conduit is about 1.5 to about 10, e.g., about 1.5 to about 5. In a particular example, the inner diameter of the outer fluid conduit is about 40.5 mm and the inner diameter of the inner fluid conduit is about 4.8 mm. In some embodiments, the flow mixer has a total length in the z-direction of about 76 to about 510 mm, e.g., about 102 to about 508 mm, e.g., about 124.5 mm. The flow mixer can be made from a variety of materials that are compatible with the metal-containing precursors, including aluminum, stainless steel, and ceramic.

[0227] Multi-plenum shower head In another aspect, a multi-plenum showerhead is provided for delivering multiple reactants to a processing chamber. The showerhead can be used to deliver any combination of reactants, including, but not limited to, the molybdenum-containing precursor and the tungsten-containing precursor described herein. In some embodiments, the multi-plenum showerhead includes: (a) a showerhead faceplate having a first plurality of conduits for delivering a first reactant and a second plurality of conduits for delivering a second reactant, the first plurality of conduits being configured to be fluidly isolated from the second plurality of conduits; and (b) a showerhead housing positioned around the showerhead faceplate, the showerhead housing being releasably attached to the showerhead faceplate. Because the showerhead is configured with a removable faceplate, cleaning of the faceplate, which typically includes very small channels, can be performed with high efficiency. For example, the faceplate can be cleaned with a solvent by immersing the faceplate in the solvent and / or purging the channels with the solvent. In some embodiments, the faceplate includes openings having a diameter of about 1 mm or less, such as 0.5 mm or less, that can be effectively cleaned after the faceplate is removed from the base.

[0228] In some embodiments, the multi-plenum showerhead is a dual plenum showerhead, where a first plurality of conduits is configured to deliver a reactant (e.g., H2, NH3, SiH4, B2H6, a hydrocarbon, etc.) and a second plurality of conduits is configured to deliver a metal-containing precursor (e.g., a molybdenum-containing precursor or a tungsten-containing precursor).

[0229] FIG. 11A shows a view of a portion of a dual plenum showerhead 1101 including a faceplate 1103 and a housing 1105 attached to the faceplate 1103, the housing 1105 being positioned around the periphery of the faceplate 1103. The upper portion of the faceplate 1103 includes multiple openings of conduits 1107 configured to deliver metal-containing precursors through the faceplate. The metal-containing precursors are delivered downward onto the faceplate and are confined by the showerhead housing on the side. The faceplate 1103 also includes multiple fluid conduits 1106, the fluid conduits 1106 not in fluid communication with the metal precursor conduits 1107. The conduits 1106 are configured to receive reactants (e.g., H2, NH3, etc.) from a reactant delivery ring 1109 located within the housing 1105 and distribute the reactants laterally through the showerhead faceplate 1103. The reactant conduit 1106 has multiple outlets at the bottom of the faceplate 1103 (not shown) configured to deliver the reactants to the processing chamber. These outlets have diameters of about 1 mm or less or 0.5 mm or less in some embodiments. The outlets of both the metal precursor conduit and the reactant conduit open into the processing chamber. The conduits are designed so that the metal precursor and the reactants do not contact each other within the body of the showerhead 1101.

[0230] The showerhead faceplate 1103 serves to distribute and deliver the metal precursor and reactants to the processing chamber without mixing, while the showerhead housing 1105 serves to confine a volume for the metal precursor above the showerhead faceplate 1103 and house a delivery ring 1109 configured to deliver the reactants to the reactant conduits 1106 of the showerhead faceplate 1103. The flow of the reactants through is indicated by arrows 1110. The housing can further include a heater 1111, which is annular in shape and may be embedded in a recess formed in the housing. The housing also typically includes a ledge 1113 for supporting an O-ring or another seal for sealing the showerhead to the metal precursor delivery line. FIG. 11B shows the showerhead faceplate 1103 and a portion of the showerhead housing 1105 after the faceplate 1103 has been released from the housing 1105 (e.g., for cleaning). This view shows removable fasteners 1115 that are configured to fit into openings in the housing 1105 and releasably attach the housing 1105 to the faceplate 1103 using openings around the perimeter of the faceplate 1103 .

[0231] The showerhead faceplate can be made from any material that is compatible with the metal-containing precursors, such as aluminum, stainless steel, and ceramic materials.

[0232] Further embodiments The apparatus and processes described herein may be used in conjunction with lithographic patterning tools or processes, for example, for the fabrication or manufacture of semiconductor devices, displays, LEDs, solar panels, and the like. Typically, but not necessarily, such apparatus and processes are used or performed together in a common fabrication facility. Lithographic patterning of a film typically includes some or all of the following steps, each of which is enabled with many available tools: (1) applying photoresist to a workpiece (i.e., substrate) using a spin-on or spray-on tool; (2) curing the photoresist using a hotplate or furnace or UV curing tool; (3) exposing the photoresist to visible or UV or eUV or X-ray light using a tool such as a wafer stepper; (4) developing the resist to selectively remove the resist, thereby patterning the resist, using a tool such as a wet bench; (5) transferring the resist pattern to an underlying film or workpiece by using a dry etching tool or a plasma-assisted etching tool; and (6) removing the resist using a tool such as an RF or microwave plasma resist stripper.

[0233] Process Chamber Cleaning Also provided herein is a method for cleaning the interior of a process chamber and / or components within the process chamber. Some semiconductor device fabrication operations may involve various deposition processes that deposit various films to form integrated circuits and related devices by various methods including CVD, PECVD, ALD, or PEALD. As a result of the deposition processes, various materials are deposited on the substrate being deposited on as well as on the interior surfaces of the process chamber in which the deposition process occurs. As a result, deposits from various materials are formed on the interior surfaces of the process chamber, including the interior walls of the process chamber or the surfaces of one or more components within the process chamber, and the deposited materials may accumulate over time and form films or particles. In addition, the deposited materials may dissolve, peel, thermally desorb, or evaporate through subsequent processes in the process chamber, causing contamination of the substrate or features formed on the substrate. This contamination is one reason for low production yields / throughput, or device reliability issues. To avoid contamination of the process chamber, the accumulated materials are periodically removed.

[0234] The methods described herein can be used to remove contaminants after deposition of metal-containing films, including those deposited by the methods described above. They can also be used to remove contaminants resulting from the deposition of other types of films, including dielectric films, as described further below.

[0235] One method of removing contaminants deposited on interior surfaces in a process chamber may involve introducing a plasma containing fluorine (F) species. Radicals may be one or more species generated in the plasma, and plasma activated species may include radicals. Radicals may be referred to as radical species. Species may include source gases, plasmas (e.g., radicals, ions, charged neutrals), or mixtures thereof. In some embodiments, plasmas may include radicals, ions, charged neutrals, or mixtures thereof. In one example, the fluorine-containing species includes a fluorine-containing source gas, a fluorine-containing plasma (e.g., radicals, ions, charged neutrals), or mixtures thereof. In another example, the oxygen-containing species includes an oxygen-containing source gas, an oxygen-containing plasma (e.g., radicals, ions, charged neutrals), or mixtures thereof.

[0236] For this type of cleaning, one or more source gases (e.g., cleaning gases) including nitrogen trifluoride (NF3), fluorine (F2), carbon tetrafluoride (CF4), carbon hexafluoride (C2F6), octafluoropropane (C3F8), other fluorine-containing compounds (i.e., fluorine-containing reactants), or mixtures thereof may be supplied to a plasma source. The plasma source may be an inductively coupled plasma reactor, a capacitively coupled plasma reactor, a microwave plasma reactor, a DC plasma reactor, or a laser-produced plasma reactor. The plasma generated from the plasma source may include one or more radicals and may flow into the process chamber to remove built-up material deposited on the interior surfaces of the process chamber.

[0237] Cleaning of Molybdenum-containing Films Molybdenum nitride (MoNx, 0 < X ≤ 2) can be used for the gate electrode stack in a transistor structure. The molybdenum nitride film-based gate electrode stack can provide an appropriate work function for a metal-oxide-semiconductor field-effect transistor (MOSFET). Some applications, including fin field-effect transistor (finFET) structures and dynamic random access memory (DRAM) bit structures, may involve the deposition of MoNx films to form the gate electrode stack. MoNx can also be used for patterning the film due to its selectivity in wet etching.

[0238] The MoNx film can be deposited by any suitable deposition method using one or more molybdenum-containing precursors, such as ALD, PEALD, CVD, or PECVD. The deposition method can include any of those described above with reference to FIGS. 1A - 11B. The cleaning method is not limited to the films deposited by those methods, and any method can be used to clean the chamber after the deposition of the MoNx film by any suitable method.

[0239] The MoNx film can be formed not only on the substrate where the MoNx film is considered to be formed but also on the inner surface of the process chamber. The inner surface includes the inner wall of the process chamber or the surface of any component that can be located within the process chamber. For example, the inner surface can include the inner wall surface of the process chamber, the outer surface of the showerhead, the outer surface of the pedestal, the surface of the gas line, the surface of the nozzle, the surface of the lift pin, and the surface of other components of the chamber. After repeated deposition of the MoNx film, MoNx and other materials that can be deposited or etched within the process chamber may also be deposited on the inner surface of the process chamber, and these can be periodically cleaned from the inner surface to avoid further contamination of the substrate in subsequent semiconductor manufacturing processes.

[0240] Process Flow 12 shows a flowchart 1200 of an exemplary method for cleaning an inner surface of a process chamber according to some embodiments. In optional operation 1210, a substrate may be provided in a process chamber for depositing a molybdenum-containing layer on the substrate. In some embodiments, a substrate having one or more features may be transferred to the process chamber. For example, the one or more features on the substrate may be one or more partially fabricated integrated circuits. Prior to optional operation 1210, the substrate may be cleaned to remove any undesired layers deposited on the substrate.

[0241] In optional operation 1220, a molybdenum-containing layer may be deposited in one or more features on the substrate. The molybdenum-containing layer may include molybdenum metal, molybdenum nitride (MoNx), molybdenum oxynitride (MoOxNy, 0≦x≦1, y=1-x), molybdenum oxide (MoOx, 0≦x≦1), molybdenum oxycarbonitride (MoNxOyCz, 0≦x≦1, 0≦y≦1, y=1-x), or mixtures thereof. In some embodiments, the molybdenum-containing layer may be doped or undoped. For example, the molybdenum-containing layer may be doped with carbon.

[0242] Molybdenum-containing layers can be deposited using molybdenum-containing precursors in a vapor deposition process, such as ALD, PEALD, CVD, or PECVD. In general, molybdenum-containing precursors can include molybdenum in a wide range of oxidation states from 0 to +6. In some embodiments, the molybdenum compounds have molybdenum in lower oxidation states of +3, +4, and +5. The provided methods are particularly useful for depositing molybdenum-containing materials from halogen-containing molybdenum-containing compounds, since the silicon-containing reactant can assist in scavenging the halogen, but halogen-free molybdenum-containing precursors can be used as well. Suitable molybdenum-containing precursors include halides and oxyhalides of molybdenum, such as fluorides, chlorides, bromides, oxyfluorides, oxychlorides, and oxybromides, where the molybdenum can be in any of the oxidation states from +2 to +6.

[0243] Molybdenum-containing precursors for depositing the molybdenum-containing layer can include the precursors described above. In some embodiments, the molybdenum-containing precursors include molybdenum halide precursors and molybdenum oxyhalide precursors. Examples of molybdenum halide precursors include molybdenum chloride. Molybdenum chloride can be represented by the formula MoCl x where x is 2, 3, 4, 5, or 6, including molybdenum dichloride (MoCl2), molybdenum trichloride (MoCl3), molybdenum tetrachloride (MoCl4), molybdenum pentachloride (MoCl5), and molybdenum hexachloride (MoCl6). In some embodiments, MoCl5 or MoCl6 are used. The description is primarily focused on MoCl x Although the precursor is mentioned, in other embodiments, other molybdenum halide precursors may be used. The molybdenum halide precursors have the formula MoX z where X is a halogen (e.g., fluorine (F), chlorine (Cl), bromine (Br), or iodine (I)) and z is 2, 3, 4, 5, or 6. MoX zExamples of precursors include molybdenum fluoride (MoF6). In some embodiments, non-fluorine-containing MoX are used to prevent etching or incorporation of fluorine. z In some embodiments, a precursor is used that is non-bromine-containing and / or non-iodine-containing MoX z The precursors are used to prevent etching or incorporation of bromine or iodine.

[0244] The molybdenum oxyhalide precursor has the formula MoO y X z where X is a halogen (fluorine (F), chlorine (Cl), bromine (Br), or iodine (I)) and y and z are MoO y X z is a number greater than 0 such that a stable compound is formed. Examples of molybdenum oxyhalide precursors include molybdenum oxide tetrafluoride (MoOF4), molybdenum oxide tetrachloride (MoOCl4), molybdenum dioxide dichloride (MoO2Cl2), molybdenum dioxide dibromide (MoO2Br2), and molybdenum oxyiodide (MoO2I and Mo4O 11 I) can be mentioned.

[0245] In some embodiments, the precursor has a molecular weight of less than about 450 g / mol, such as less than about 400 g / mol.

[0246] In some embodiments, the molybdenum-containing precursor has the formula MoX n Y m where X is a chalcogen (e.g., oxygen or sulfur), Y is a halogen (e.g., fluorine, chlorine, bromine, or iodine), n is 0, 1, or 2, and m is 2, 3, 4, 5, or 6. Examples of halogen-containing molybdenum-containing precursors include, but are not limited to, MoCl5, Mo2Cl 10 , MoO2Cl2, and MoOCl4. Another example of a halogen-containing molybdenum-containing precursor is MoF6.

[0247] In some embodiments, the molybdenum-containing precursor comprises a carbonyl ligand. One example of a carbonyl-containing precursor is Mo(CO).

[0248] Different molybdenum-containing precursors are described in U.S. patent application Ser. No. 62 / 816,648, filed March 11, 2019, entitled "Precursors for Deposition of Molybdenum-Containing Films," and U.S. patent application Ser. No. 63 / 366,888, filed June 23, 2022, entitled "Remote Plasma Low Temperature Atomic Layer Deposition of Metals," each of the above disclosures are incorporated herein by reference in their entirety for all purposes.

[0249] In some embodiments, the molybdenum-containing layer may be formed in one or more features of the substrate by ALD. In some embodiments, thermal ALD may be used to form the molybdenum-containing layer. In thermal processes, no plasma is used. ALD is a surface-mediated deposition technique in which fixed amounts of reactants are sequentially introduced into a process chamber. For example, the molybdenum-containing layer may be deposited using one or more cycles of sequential administration of a molybdenum-containing precursor and one or more co-reactants. In one example, the molybdenum-containing precursor may be pulsed to adsorb to the substrate at high temperature to form the molybdenum-containing layer. The molybdenum-containing precursor may include a hydrocarbon, and carbon in the molybdenum-containing precursor may not be completely removed during deposition of the molybdenum-containing layer. As a result, carbon may remain in the molybdenum-containing layer deposited on the interior surface. For example, the molybdenum-containing layer may be undoped or doped with carbon. For example, carbon may be included in the molybdenum-containing layer as a contaminant or dopant. In another example, carbon may be present on the surface of the molybdenum-containing layer as a very thin layer.

[0250] In some embodiments, the molybdenum-containing layer can include molybdenum oxynitride (MoOxNy). For example, the MoOxNy layer can be formed by flowing a molybdenum halide precursor or a molybdenum oxyhalide precursor as a precursor, and oxygen (O2) and nitrogen (N2) as co-reactants. The MoOxNy layer can be formed by flowing a molybdenum precursor as described in U.S. Patent Application No. 62 / 816,648, entitled "precursors for deposition of molybdenum-containing films," filed March 11, 2019, the disclosure of which is incorporated herein by reference in its entirety for all purposes. A mixture of oxygen and nitrogen having a predetermined mixing ratio can be introduced into the process chamber and reacted with the precursor to deposit the MoOxNy layer. The substrate can be heated to about 150° C. to about 650° C. The process chamber can be pressurized to a pressure of about 1 Torr to about 200 Torr. In some embodiments, the MoOxNy film can be reduced to form a MoNx film by flowing one or more reducing agents, such as nitrogen, argon, hydrogen, ammonia, other hydrogen-containing gases, and mixtures thereof, at a temperature between about 150° C. and about 650° C.

[0251] In operation 1230, a molybdenum-containing film is formed on the interior surfaces of the process chamber. The molybdenum-containing film may constitute unwanted molybdenum-containing material formed on the interior surfaces, such as the chamber walls, ceiling, showerhead, substrate support, gas lines, and other regions of the process chamber. In operation 1220, a molybdenum-containing precursor may be flowed onto the substrate to form a molybdenum-containing layer. In some embodiments, depending on the parameters for depositing the molybdenum-containing layer, the one or more molybdenum-containing precursors may also be delivered to locations other than the substrate in the process chamber, such as the chamber walls, remote areas away from the substrate, or to surfaces of one or more chamber components, such as the pedestal, showerhead, gas lines, etc. The one or more molybdenum-containing precursors may also form deposits in the form of layers or particles. This deposit may accumulate over a period of time as the one or more molybdenum-containing precursors are deposited in the process chamber, or depending on the number of substrates on which the molybdenum-containing layer is deposited. After a molybdenum-containing layer has been deposited on a certain number of substrates, or after a certain deposition or processing time has elapsed in the process chamber, the substrates may be removed from the process chamber to clean the interior surface of the process chamber. In one example, the molybdenum-containing layer may be formed according to operation 120. In some embodiments, the presence of a molybdenum-containing film on the interior surface is believed to be due to a molybdenum-containing layer remaining from an etching operation prior to cleaning the interior surface. In some embodiments, the molybdenum-containing film on the interior surface of the process chamber may include a carbon and molybdenum-containing layer, such as undoped or carbon-doped MoOx, undoped or carbon-doped MoNx, undoped or carbon-doped MoOxNy, or molybdenum metal. After the substrates are removed from the process chamber, the chamber pressure may be adjusted to a certain pressure range prior to cleaning the interior surface of the process chamber. In some embodiments, the process chamber pressure may be in a range from about 2 Torr to about 6 Torr, from about 2.5 Torr to about 5.5 Torr, from about 3 Torr to about 5 Torr, from about 0.5 Torr to about 2 Torr, from about 0.5 Torr to about 1.8 Torr, or from about 0.5 Torr to about 1.6 Torr.

[0252] After the molybdenum-containing film is formed on the interior surfaces of the process chamber, a fluorine-containing source gas and an oxygen-containing source gas can be supplied to the plasma source to generate a plasma containing fluorine-containing and oxygen-containing species in operation 1240. As described below, the fluorine-containing source gas and the oxygen-containing source gas can be supplied in a circulating flow or a co-flow.

[0253] In some embodiments, the fluorine-containing source gas may include nitrogen trifluoride, fluorine (F2), molecular fluorine, carbon tetrafluoride, carbon hexafluoride, xenon difluoride, fluoromethane, difluoromethane, tetrafluoroethylene, hexafluoroethane, octafluoropropane, sulfur hexafluoride, or mixtures thereof. In some embodiments, the oxygen-containing source gas may include oxygen, ozone, carbon monoxide, carbon dioxide, nitrous oxide, nitrogen dioxide, or mixtures thereof. In some embodiments, one or more source gases may be provided with an inert gas (i.e., carrier gas), such as argon, helium, neon, krypton, xenon, or mixtures thereof. One or both of the fluorine-containing source gas and the oxygen-containing source gas may be mixed with an inert gas. Each of the fluorine-containing source gas and the oxygen-containing source gas may be ignited to generate a plasma including fluorine-containing species (e.g., radicals) and oxygen-containing species (e.g., radicals). The fluorine-containing radicals may be fluorine-containing species generated from the plasma and may include ions, charged neutrals, or mixtures thereof. The oxygen-containing radicals may be oxygen-containing species generated from the plasma and may include ions, charged neutrals, or mixtures thereof.

[0254] The plasma may be generated in-situ adjacent to the processing zone where the deposition or etching operation takes place. Alternatively, the plasma may be generated from a remote plasma source. The remote plasma source may be located upstream of the process chamber and separated from the process chamber by a showerhead. In some embodiments, the remote plasma source may be a subunit that may be removably bolted to the side of the process chamber. The remote plasma source may be constructed such that the plasma from the remote plasma source may flow horizontally or vertically depending on the location of the remote plasma source relative to the showerhead and / or pedestal. In one example, the plasma may be delivered across the showerhead from a remote plasma source positioned on the side of the process chamber.

[0255] The fluorine-containing source gas and the oxygen-containing source gas can be provided to the process chamber either cyclically or simultaneously (co-flow), as described below.

[0256] circulation flow In operation 1240, a fluorine-containing source gas and an oxygen-containing source gas can be periodically provided to the plasma source to generate fluorine-containing and oxygen-containing species. In operation 1250, the fluorine-containing and oxygen-containing species generated in the plasma source can be periodically introduced into the process chamber as well. In some embodiments, the circulating flow can include two operations: (a) providing a fluorine-containing source gas to the plasma source, generating fluorine-containing radicals (operation 1240), and introducing the fluorine-containing species into the process chamber (operation 1250), followed by (b) providing an oxygen-containing source gas to the plasma source, generating oxygen-containing species (operation 1240), and introducing the oxygen-containing species into the process chamber (operation 1250). In other embodiments, the fluorine-containing source gas can be provided to the plasma source after the oxygen-containing source gas is provided to the plasma source.

[0257] In some embodiments, an appropriate amount of one or more inert gases may be premixed with each of the fluorine-containing and oxygen-containing source gases before the fluorine-containing and oxygen-containing radicals are provided to the process chamber. In some embodiments, one of the species may be provided to the process chamber without being struck by a plasma. In one example, fluorine-containing species (e.g., fluorine-containing radicals) from a plasma and an oxygen-containing source gas such as ozone may be periodically flowed into the process chamber. In another example, a fluorine-containing source gas, e.g., fluorine (F2), and an oxygen-containing species (e.g., oxygen-containing radicals) may be periodically flowed into the process chamber. Regardless of the type of species introduced, the fluorine-containing and oxygen-containing species may be periodically flowed toward the interior surface of the process chamber. One or both of the fluorine-containing and oxygen-containing species may react with the molybdenum-containing film, thereby removing the molybdenum-containing film from the interior surface. For example, the fluorine-containing species may react with the molybdenum in the molybdenum-containing film to form molybdenum fluoride, e.g., molybdenum hexafluoride (MoF6), which is volatile and may be removed from the process chamber by a vacuum pump. Oxygen-containing species that are periodically introduced into the process chamber remove carbon by oxidizing the carbon or carbon-containing compositions in the molybdenum-containing film to produce volatile by-products, such as carbon monoxide (CO) or carbon dioxide (CO), from the molybdenum-containing film, and accelerate the decomposition of the molybdenum-containing film from the interior surface.

[0258] parallel current In operation 1240, the fluorine-containing species and the oxygen-containing radicals may be co-flowed toward the inner surface of the process chamber. In this co-flow, the fluorine-containing source gas, the oxygen-containing source gas, and the inert gas may be co-flowed into the plasma source. In some embodiments, two or more fluorine-containing source gases and / or two or more oxygen-containing source gases may be provided. The fluorine-containing source gas and the oxygen-containing source gas may be premixed before being provided to the plasma source. Alternatively, they may be provided separately until they reach the inlet of the plasma source where they are co-flowed. A plasma including the fluorine-containing species and the oxygen-containing species may be generated in the plasma source by igniting a plasma from a mixture of the source gas and the inert gas. In operation 150, the fluorine-containing species and the oxygen-containing species generated in the plasma source may be introduced toward the inner surface of the process chamber simultaneously to clean the molybdenum-containing film. In some embodiments, one of the species may be provided to the process chamber without colliding with the plasma. In one example, the fluorine-containing species from the plasma (e.g., the fluorine-containing plasma) and the oxygen-containing source gas, such as ozone, may be co-flowed into the process chamber. In another example, a fluorine-containing source gas, such as fluorine, and an oxygen-containing species (eg, an oxygen-containing plasma) may be co-flowed into the process chamber.

[0259] In operation 1250, in some embodiments, volatile reaction by-products such as molybdenum hexafluoride may be produced from the reaction between the fluorine-containing species and the molybdenum, and may be removed from the process chamber by a vacuum pump. The oxygen-containing species may oxidize carbon or carbon-containing compositions that may be present in the molybdenum-containing film and produce other volatile reaction by-products (e.g., CO or CO2) from the molybdenum-containing film, thereby accelerating the decomposition of the molybdenum-containing film. The carbon concentration on the interior surface may be reduced to a zero or near-zero level, thereby clearing the interior surface of contaminants. In the case of co-flow, the formation of volatile molybdenum fluoride by-products and volatile carbon-containing by-products (e.g., CO or CO2) may occur substantially simultaneously.

[0260] After removing the molybdenum-containing film from the interior surfaces, either by circulating flow or simultaneous co-flow, one or more inert gases (e.g., helium, neon, argon, krypton, xenon, or mixtures thereof) may be pulsed into the process chamber, followed by an optional purge operation, to remove residual fluorine-containing species, oxygen-containing species, or any reaction by-products from the process chamber.

[0261] In optional operation 160, a substrate can be provided to a process chamber for subsequent operations. For example, the substrate can be transported by a transfer tool for depositing a molybdenum-containing layer on the substrate. The molybdenum-containing layer can be deposited by ALD, PEALD, CVD, PECVD, or any suitable deposition process.

[0262] Processing conditions for recirculating or parallel flow Figure 13 shows a flowchart 1300 of an exemplary method for cleaning an internal surface of a process chamber according to some embodiments. Optional operations 1310, 1320, and 1330 of Figure 13 may be substantially identical to optional operations 1210, 1220, and 1230 of Figure 12, and further description of optional operations 1310, 1320, and 1330 will be omitted.

[0263] In operation 1340, one or more fluorine-containing source gases (e.g., NF3) and one or more oxygen-containing source gases (e.g., O2) may be supplied to a remote plasma source, where a plasma containing fluorine-containing and oxygen-containing species may be generated and maintained. In some embodiments, NF3 gas and O2 gas may be supplied to the remote plasma source as source gases. An inert gas, e.g., helium, neon, argon, krypton, xenon, or mixtures thereof, may also be supplied to the remote plasma source. The flow ratio between NF3, O2, and the inert gas may be adjusted as needed. In some embodiments, the fluorine-containing source gas, the oxygen-containing source gas, and one or more inert gases may be introduced according to the circulating flow or simultaneous co-flow described above. The circulating flow or simultaneous co-flow may be provided with certain process conditions, such as flow rates of the source gas and one or more inert gases, chamber pressure, and substrate temperature, which may individually or collectively contribute to the cleaning (etching) capabilities of the fluorine-containing and oxygen-containing species generated in the plasma source (e.g., remote plasma source). In some embodiments, Table 1 includes a set of process conditions A at a higher chamber pressure range, which includes process conditions A1-A3. In some embodiments, Table 2 includes a set of process conditions B at a lower chamber pressure range, which includes process conditions B1-B3.

[0264] The process conditions in Tables 1 and 2 may be designed based on the location and / or composition of the molybdenum-containing film on the inner surface of the process chamber. In some embodiments, a higher chamber pressure may reduce ionization of the source gas and increase recombination. For example, the chamber pressure may be adjusted from about 2 Torr to about 6 Torr, about 2.5 Torr to about 5.5 Torr, or about 3 Torr to about 5 Torr (as shown in Table 1) to promote removal of molybdenum-containing films (e.g., MoNx) located on or near a pedestal or carrier ring. In some embodiments, a lower chamber pressure may promote ionization of the source gas and reduce recombination. The reduced recombination may be beneficial in removing molybdenum-containing films formed on ceilings or other inner surfaces where species (e.g., radicals and / or ions) take a relatively long time to travel. For example, the presence of chamber parts or structures (e.g., showerhead) in the process chamber may delay or block the transport of fluorine-containing and / or oxygen-containing species to the ceiling or other isolated areas, in which case an increased number of radicals or ions with reduced recombination may be more effective in removing molybdenum-containing films. For example, in removing molybdenum-containing films (e.g., MoOx) deposited on areas requiring longer transport times for the species, a lower chamber pressure in the range of about 0.5 Torr to about 2 Torr, about 0.5 Torr to about 1.8 Torr, or about 0.5 Torr to about 1.6 Torr may be desirable (as shown in Table 2). In some embodiments, the presence of a carrier gas may have the same effect as lowering the chamber pressure. For example, the flow rate of the inert gas may be higher in Table 2 than in Table 1, further increasing the ionization of the source gas and reducing recombination compared to Table 1.

[0265] According to some embodiments, the removal of the molybdenum-containing film may involve one or more process conditions. In the case of cyclic flow, in some embodiments, the fluorine-containing source gas and the oxygen-containing source gas may be periodically supplied to the plasma source according to any one of the process conditions listed in Tables 1 and 2. In some embodiments, the fluorine-containing source gas and the oxygen-containing source gas may be supplied to the plasma source under different process conditions. One or more inert gases may be mixed with each of the fluorine- and oxygen-containing source gases. In the case of parallel flow, the fluorine-containing source gas, the oxygen-containing source gas, and the inert gas may be simultaneously supplied to the plasma source in parallel flow according to any one of the process conditions in Tables 1 and 2. In some embodiments, the parallel flow may be repeated multiple times according to another process condition in Tables 1 and 2. [Table 1] [Table 2]

[0266] Operation 1340 may be followed by operation 1350, where the fluorine-containing and oxygen-containing species generated in operation 1340 may be introduced into the process chamber. The fluorine-containing and oxygen-containing species may be introduced into the process chamber in the same manner that the fluorine-containing and oxygen-containing source gases are supplied to the plasma source. In the case of a circulating flow, a first source gas (e.g., a fluorine-containing source gas) flowing at a flow rate according to one of the process conditions A1-A3 and B1-B3 may be mixed with an inert gas flowing at an appropriate flow rate and supplied to the plasma source, and then the first species generated from the first source gas may flow into the process chamber. Subsequently, a second source gas (e.g., an oxygen-containing source gas) flowing at a flow rate of the process condition selected for the first source gas may be mixed with an inert gas flowing at an appropriate flow rate and supplied to the plasma source, where the second species is generated and flowed into the process chamber to clean the inner surfaces of the process chamber. In some embodiments, the total flow rate of the inert gas mixed with the first and second source gases may correspond to the flow rate of the inert gas at the process conditions selected for the first source gas.

[0267] In the case of co-flow, the first source gas, the second source gas, and the inert gas can be co-flowed into a plasma source (e.g., a remote plasma source) to generate a mixture containing the first and second species, which are simultaneously flowed into the process chamber. The molybdenum-containing film can be removed from the interior surface when exposed to the fluorine-containing and oxygen-containing species.

[0268] After the cleaning operation, an optional purge operation can be performed. Also, operations 1340 and / or 1350 can be repeated one or more times. In optional operation 1360, a new substrate can be transferred into the process chamber for a subsequent operation, such as a deposition or etching operation. For example, a molybdenum-containing layer can be deposited on the new substrate.

[0269] Circulating flow for removing carbon and molybdenum containing films FIG. 14 is a flowchart of an exemplary method for cleaning an inner surface of a process chamber on which a carbon- and molybdenum-containing film has been deposited, according to some embodiments. The operations of flowchart 1400 may be performed according to a circulating flow. The operations of flowchart 1400 may be performed in a different order and / or with fewer or additional operations. Flowchart 1400 begins with operation 1410, in which a fluorine-containing source gas (e.g., NF3) may be supplied to a plasma source according to one of the process conditions set forth in A1-A3 and B1-B3 of Tables 1 and 2, thereby generating fluorine-containing species. An appropriate portion of the inert gas selected for the fluorine-containing source gas in operation 1410 may also be supplied to mix with the fluorine-containing source gas. In operation 1420, the generated fluorine-containing species may be introduced into the process chamber and react with the carbon- and molybdenum-containing film, e.g., carbon-containing MoOx, carbon-containing MoNx, or carbon-containing MoOxNy, to remove the carbon- and molybdenum-containing film from the inner surface of the process chamber. The fluorine-containing species may include a fluorine-containing source gas, a fluorine-containing plasma (e.g., radicals, ions, charged neutrals), or a mixture thereof. Subsequently, in operation 1430, an oxygen-containing source gas (e.g., O2) may be supplied to the plasma source according to the process conditions selected for the fluorine-containing source gas in operation 1410 to generate the oxygen-containing species in the plasma source. An appropriate portion of an inert gas may also be supplied to mix with the oxygen-containing source gas. In operation 1440, the oxygen-containing species generated in operation 1430 may be introduced into the process chamber to oxidize carbon or carbon-containing compositions in the carbon- and molybdenum-containing film. In some embodiments, the oxygen-containing species may include an oxygen-containing source gas, an oxygen-containing plasma (e.g., radicals, ions, charged neutrals), or a mixture thereof.

[0270] The flow rates for the fluorine-containing source gas in operation 1410 and the oxygen-containing source gas in operation 1430 may be selected from any of the process conditions in Tables 1 and 2. The flow rates for operations 1410 and 1430 may be configured to be the same or different from one another. After operation 1440 is completed, in operation 1450, operations 1410-1440 may be optionally repeated one or more times as desired.

[0271] Co-flow for removing carbon and molybdenum containing films FIG. 15 is a flowchart of an exemplary method of cleaning the interior surface of a process chamber on which a carbon- and molybdenum-containing film has been deposited according to some embodiments. The operations of flowchart 1500 may be performed according to a co-flow. The operations of flowchart 1500 may be performed in a different order and / or with fewer or additional operations. In operation 1510, a fluorine-containing source gas (e.g., NF3), an oxygen-containing source gas (e.g., O2), and an inert gas may be supplied to a plasma source as a co-flow according to one or more of the process conditions A1-A3 and B1-B3 of Tables 1 and 2 to generate fluorine-containing and oxygen-containing species in the plasma source. In operation 1520, the generated fluorine-containing and oxygen-containing species may be introduced into the process chamber and reacted with the carbon- and molybdenum-containing film.

[0272] In some embodiments, the process condition may be one of the process conditions described in A1-A3 and B1-B3, and the chamber pressure may not be changed until the chamber cleaning is completed. In some embodiments, the chamber cleaning may involve two or more process conditions, and the process chamber pressure may be modified during the cleaning. For example, the chamber may be exposed to a fluorine-containing species and an oxygen-containing species for a first period of time at a first chamber pressure, and then the chamber pressure may be changed to a second chamber pressure for a second period of time. In some embodiments, the chamber pressure may change from a higher pressure to a lower pressure. For example, the first chamber pressure may be about 2 Torr to about 6 Torr, about 2.5 Torr to about 5.5 Torr, or about 3 Torr to about 5 Torr, and the second chamber pressure may be about 0.5 Torr to about 2 Torr, about 0.5 Torr to about 1.8 Torr, or about 0.5 Torr to about 1.6 Torr. In some embodiments, the chamber pressure may change from a lower pressure to a higher pressure. For example, the first chamber pressure can be from about 0.5 Torr to about 2 Torr, and the second chamber pressure can be from about 2 Torr to about 6 Torr.

[0273] In some embodiments, the fluorine-containing species may include a fluorine-containing source gas, a fluorine-containing plasma (e.g., radicals, ions, charged neutrals), or a mixture thereof, and the oxygen-containing species may include an oxygen-containing source gas, an oxygen-containing plasma (e.g., radicals, ions, charged neutrals), or a mixture thereof. For example, during a first period of time, the chamber may be exposed to a fluorine-containing plasma and an oxygen-containing plasma, and during a second period of time, the chamber may be exposed to a fluorine-containing plasma and an oxygen-containing species in a plasma-free environment (e.g., ozone or other oxygen-containing source gas). Alternatively, during a first period of time, the chamber may be exposed to a fluorine-containing plasma and an oxygen-containing species in a plasma-free environment, and during a second period of time, the chamber may be exposed to a fluorine-containing plasma and an oxygen-containing plasma. An optional purge operation may be performed after operation 1520.

[0274] In optional operation 1530, operations 1510 and 1520 may be performed repeatedly one or more times. The process conditions in operation 1530 may be the same or different from the flow conditions employed in operation 1510 performed prior to performing operation 1530.

[0275] Device 16 shows a schematic diagram of an exemplary processing apparatus having a remote plasma source according to some embodiments. It will be understood that the process chamber of FIG. 16 can be used to deposit a silicon-containing layer or a molybdenum-containing layer and / or to etch a silicon-containing layer or a molybdenum-containing layer formed in the process chamber according to some embodiments. In some embodiments, the silicon-containing layer or the molybdenum-containing layer may be formed in the process chamber and then etched in the same process chamber using a remote plasma source without exposing the silicon-containing layer or the molybdenum-containing layer to an ambient atmosphere.

[0276] The plasma processing apparatus 1600 includes a remote plasma source 1602 separated from the process chamber 1604. The remote plasma source 1602 is fluidly coupled to the process chamber 1604 via a gas distributor or showerhead 1606. In some embodiments, the showerhead 506 includes an ion filter for filtering ions to limit damage from ion bombardment to the substrate 1612. Radical species and / or ions can be generated in the remote plasma source 1602, and the radical species can be delivered to the process chamber 1604. Precursors, such as one or more molybdenum-containing precursors, are delivered to the process chamber 1604 through one or more precursor gas outlets 1608 (e.g., manifolds) positioned downstream of the remote plasma source 1602 and the showerhead 1606. A pressure gauge, butterfly valve, or any other pressure monitoring device can be fluidly coupled to the process chamber 1604 to maintain a particular pressure range of the process chamber 1604 when one or more molybdenum-containing precursors are flowing into the process chamber.

[0277] The substrate 1612 is supported on a substrate support structure or wafer pedestal 1614. The wafer pedestal 1614 may be configured with lift pins or other movable support members to position the substrate 1612 within the process zone (i.e., deposition / etch zone 1610). The substrate 1612 may be moved to a position closer to the showerhead 1606 or further away from the showerhead 1606. The wafer pedestal 1614 is shown in FIG. 16 as elevating the substrate 1612 within the deposition / etch zone 1610.

[0278] In some embodiments, the wafer pedestal 1614 includes an electrostatic chuck 1616. The electrostatic chuck 1616 includes one or more electrostatic clamping electrodes 1618 embedded within the body of the electrostatic chuck 1616. In some embodiments, the one or more electrostatic clamping electrodes 1618 may be coplanar or substantially coplanar. The electrostatic clamping electrodes 1618 may be powered by a DC power source or a DC chucking voltage (e.g., about 200 V to about 2000 V) such that the substrate 512 may be held on the electrostatic chuck 1616 by electrostatic attraction. Power to the electrostatic clamping electrodes 1618 may be provided via a first electrical wire 1620. The electrostatic chuck 1616 may further include one or more heating elements 1622 embedded within the body of the electrostatic chuck 1616. The one or more heating elements 1622 may include resistive heaters. In some embodiments, the one or more heating elements 1622 are positioned below the one or more electrostatic clamping electrodes 1618. The one or more heating elements 1622 may be configured to heat the substrate 1612 to a temperature greater than about 450° C., greater than about 500° C., greater than about 550° C., greater than about 600° C., or greater than about 650° C. The one or more heating elements 1622 provide selective temperature control to the substrate 1612. Power to the one or more heating elements 1622 may be supplied via a second electrical wire 1624.

[0279] A coil 1628 is disposed around the remote plasma source 1602, which includes an outer wall (e.g., a quartz dome). The coil 1628 is electrically coupled to a plasma generator controller 1632, which may be used to form and maintain a plasma in the plasma region 1634 via inductively coupled plasma generation. In some embodiments, the plasma generator controller 1632 may include a power source for providing power to the coil 1628, which may range from about 300 W to about 15 kW per station, or from about 1 kW to about 10 kW per station during plasma generation. In some embodiments, it is possible to generate a continuous supply of radicals via plasma excitation rather than inductively coupled plasma generation using electrodes or antennas for parallel plate or capacitively coupled plasma generation. Regardless of the mechanism used to ignite and maintain the plasma in the plasma region 1634, radical species may be continuously generated using plasma excitation during layer formation (e.g., film deposition) and / or remote plasma processing.

[0280] In some embodiments, a fluorine radical (F * ) and hydrogen radicals (H * ), hydrogen-containing radicals, nitrogen radicals (N * ), nitrogen-containing radicals, including oxygen radicals (O * ), oxygen-containing radicals, carbon radicals (C * ), carbon-containing radicals, including the amine radical (NH * , NH2 *), amine-containing radicals, or combinations thereof, are generated in the plasma region 1634 under near steady-state conditions during steady-state film deposition or remote plasma processing controlled by the plasma generator controller 1632, although transients may occur at the beginning and end of the film deposition and / or remote plasma etch. In one example, fluorine-containing radicals may be generated in the plasma region 1634. In another example, oxygen-containing radicals may be generated in the plasma region 1634. In yet another example, both fluorine-containing and oxygen-containing radicals may be generated in the plasma region 1634. FIG. 16 illustrates the use of nitrogen (N * ) and amine radicals (NH * ), it will be understood that the aforementioned radicals are exemplary only and that other radicals may be present in addition to or in place of the radicals illustrated in FIG.

[0281] A supply of ions and radicals may be continuously generated in the plasma region 1634 while one or more source gases are supplied to the remote plasma source 1602. The ions generated in the plasma region 1634 may be filtered by an ion filter in the showerhead 1606. In this manner, the radicals generated in the plasma region 1634 may be supplied to the substrate 1612 in the process chamber 1604 while limiting ion bombardment. Conditions within the remote plasma source 1602, including the composition of the source gases supplied to the remote plasma source 1602 and the RF power supplied to the coil 1628, may be controlled to optimize the generation of desired radical species in the plasma region 1634. In some embodiments, the source gas may include an oxygen-containing reactant such as oxygen, ozone, carbon monoxide, carbon dioxide, nitrous oxide, nitrogen dioxide, or mixtures thereof, a fluorine-containing reactant such as nitrogen trifluoride, fluorine (F2), molecular fluorine, carbon tetrafluoride, carbon hexafluoride, xenon difluoride, fluoromethane, difluoromethane, tetrafluoroethylene, hexafluoroethane, octafluoropropane, sulfur hexafluoride, or mixtures thereof. In some embodiments, the source gas may include nitrogen trifluoride, fluorine (F2), oxygen, or combinations thereof.

[0282] In some embodiments, the source gas can be mixed with one or more additional gases. These one or more additional gases can be supplied to the remote plasma source 1602. In some embodiments, the source gas is mixed with one or more additional gases to form a gas mixture, where the one or more additional gases can include a carrier gas. Non-limiting examples of the additional gases can include helium, neon, argon, krypton, xenon, or mixtures thereof. The one or more additional gases can support or stabilize steady-state plasma conditions in the remote plasma source 1602 or assist in the ignition or extinguishing process of a transient plasma. In FIG. 16, a source gas supply 1636 is fluidly coupled to the remote plasma source 1602 to supply a source gas. Although not shown, another source gas supply can be fluidly coupled to the remote plasma source 1602 to supply another source gas. In some embodiments, about 5 sccm to about 4,000 sccm, or about 200 sccm to about 4,000 sccm, or about 500 sccm to about 3,000 sccm, or about 500 sccm to about 2,000 sccm, or about 500 sccm to about 1,500 sccm of source gas may be supplied from the source gas supply 1636. In addition, an additional gas supply 1638 is fluidly coupled to the remote plasma source 1602 to supply one or more additional gases. In some embodiments, one or more carrier gases (inert gases), such as helium, neon, argon, krypton, xenon, or mixtures thereof, may be supplied to the remote plasma source 1602. In some embodiments, about 1,000 sccm to about 9,000 sccm, or about 1,000 sccm to about 2,000 sccm, or about 6,000 sccm to about 9,000 sccm of one or more carrier gases may be provided from an additional gas supply 1638. Although the embodiment of Figure 16 illustrates the gas mixture of a source gas and one or more additional gases being introduced through separate gas outlets, it will be understood that the gas mixture may be introduced directly into the remote plasma source 1602.That is, a premixed dilute gas mixture can be supplied to the remote plasma source 1602 through a single gas outlet.

[0283] Plasma activated species 1642, such as excited nitrogen, hydrogen, carbon, oxygen, and / or fluorine radicals, flow from the remote plasma source 1602 and into the process chamber 1604 via one or more gas outlets (e.g., showerhead 1606). The one or more gas outlets may include one or more manifolds. A pressure gauge, butterfly valve, or other pressure monitoring device may be fluidly coupled to the process chamber 1604 to maintain a particular pressure range in the process chamber 1604 when the fluorine-containing and oxygen-containing species are flowing into the process chamber. In some embodiments, the process chamber pressure may operate in a low pressure region of about 0.5 Torr to about 2 Torr, or a high pressure region of about 2 Torr to about 6 Torr. The plasma activated species 1642 in the showerhead 1606 and in the process chamber 1604 generally do not undergo continuous plasma excitation therein. The showerhead 1606 may have multiple gas ports that diffuse the flow of plasma activated species 1642 into the process chamber 1604. In some embodiments, the gas ports can be spaced apart from one another. In some embodiments, the gas ports can be arranged as an array of regularly spaced channels or through-holes extending through a plate separating the remote plasma source 1602 and the process chamber 1604. The gas ports can smoothly distribute and diffuse existing radicals (including plasma activated species 1642) from the remote plasma source 1602 into the deposition / etch zone 1610 of the process chamber 1604 while filtering ions.

[0284] Precursor 1644 (or other process gas) can be introduced into process chamber 1604 by delivering plasma activated species 1642 from showerhead 1606 to process chamber 1604. Precursor 1644 can include a molybdenum-containing precursor. Precursor 1644 can be introduced through precursor gas outlet 1608, which can be fluidly coupled to precursor source 1640. Precursor gas outlet 1608 can include openings spaced apart from one another such that a flow of precursor 1644 can be introduced in a direction parallel to plasma activated species 1642 flowing from showerhead 1606. In some embodiments, precursor gas outlet 1608 can be located downstream of showerhead 1606. In some embodiments, precursor gas outlet 1608 is part of showerhead 1606, such as a dual plenum showerhead. The dual plenum showerhead can provide separate outlets / passages for plasma activated species 1642 and precursor 1644 to avoid mixing within showerhead 1606. In this manner, the precursor 1644 can flow through the showerhead 1606 and into the process chamber 1604 without being exposed to the plasma in the remote plasma source 1602. The precursor gas outlet 1608 can be located upstream of the deposition / etch zone 1610 and the substrate 1612. The deposition / etch zone 1610 is located inside the process chamber 1604 between the precursor gas outlet 1608 and the substrate 1612.

[0285] In a film deposition process, a significant portion of the precursor 1644 can be prevented from mixing with the plasma activated species 1642 in or adjacent to the showerhead 1606. In some embodiments, the precursor 1644 can be delivered to the substrate 1612 in a dosing phase of an ALD cycle separately from the plasma activated species 1642 delivered to the substrate 1612 during the plasma exposure phase of the ALD cycle. The adsorbed precursor 1644 can react with radicals of the plasma activated species 1642 during the plasma exposure phase of the ALD cycle to deposit a film, such as a silicon-containing layer or a molybdenum-containing layer. In some embodiments, the precursor 1644 can be delivered continuously to the substrate 1612 to interact with the plasma activated species 1642 in the deposition / etch zone 1610 to deposit a film by CVD. In some embodiments, plasma activated species 1642 can be delivered to the substrate 1612 without delivering a precursor 1644 to etch a silicon-containing or molybdenum-containing layer deposited on the substrate or on an inner surface of the process chamber, such as an interior wall.

[0286] The gas may be removed from the process chamber 1604 via an outlet 1648 that is fluidly coupled to a pump (not shown). Thus, the radical species or the purge gas may be removed from the process chamber 1604.

[0287] In some embodiments, a heat shield (not shown) may be positioned below the wafer pedestal 1614. The heat shield acts as an insulator below the wafer pedestal 1614 to mitigate heat loss due to thermal radiation, thereby reducing the amount of power required to maintain the wafer pedestal 1614 at a particular elevated temperature, and also prevents overheating of other components within the process chamber 1604 due to excess heat radiating from the wafer pedestal 1614. For example, the heat shield may be radially offset from the stem 1626 and may have a thin, annular-shaped body with a high view factor relative to the underside of the electrostatic chuck 1616. Thus, the annular-shaped heat shield may reduce radiative heat loss from the wafer pedestal 1614.

[0288] In some embodiments, a controller 1650 (e.g., a system controller) is in operative communication with the plasma processing apparatus 1600. In some embodiments, the controller 1650 includes a processor system 1652 (e.g., a microprocessor) configured to execute instructions retained in a data system 1654 (e.g., a memory). In some embodiments, the controller 1650 is in communication with the plasma generator controller 1632 and can control plasma parameters and / or conditions in the remote plasma source 1602. In some embodiments, the controller 1650 is in communication with the wafer pedestal 1614 and can control the pedestal height, electrostatic chucking and dechucking, and temperature. In some embodiments, the controller 1650 can control other process conditions, such as RF power settings, frequency settings, duty cycle, pulse time, pressure in the process chamber 1604, pressure in the remote plasma source 1602, gas flow rates from the source gas supply 1636, gas flow rates from the additional gas supply 1638 and other sources, the temperature of the wafer pedestal 1614, and the temperature of the process chamber 1604, among other process conditions.

[0289] The controller 1650 may include instructions for controlling process conditions for operation of the plasma processing apparatus 1600. The controller 1650 typically includes one or more memory devices and one or more processors. The processor may include a CPU or computer, analog and / or digital input / output connections, stepper motor controller boards, etc. Instructions for performing appropriate control operations are executed on the processor. These instructions may be stored in a memory device associated with the controller 1650 or provided over a network.

[0290] In certain embodiments, the controller 1650 controls all or most of the activities of the plasma processing apparatus 1600 described herein. For example, the controller 1650 can control all or most of the activities of the plasma processing apparatus 1600 associated with film deposition and / or remote plasma etching. The controller 1650 can also control all or most of the activities of the plasma processing apparatus 1600 associated with in-situ chamber cleaning. The controller 1650 can execute system control software that includes a set of instructions for controlling timing, gas composition, gas flow rates, chamber pressure, chamber temperature, RF power levels, substrate position, substrate temperature, and / or other parameters. In some embodiments, other computer programs, scripts, or routines stored in a memory device associated with the controller 1650 can be used. In a multi-station reactor, the controller 1650 can include different or identical instructions for different equipment stations, thus allowing the equipment stations to operate independently or synchronously.

[0291] In some embodiments, the controller 1650 may include instructions configured to perform operations such as depositing a molybdenum-containing layer on the substrate 1612 and exposing the inner surfaces of the process chamber 1604 to plasma activated species 1642 generated by the remote plasma source 1602 to remove a molybdenum-containing film formed on the inner surfaces of the process chamber 1604. In some embodiments, exposing the inner surfaces of the process chamber 1604 to the plasma activated species 1642 is performed by adjusting one or more of the following parameters: chamber pressure, substrate temperature, exposure time, and flow rates of one or more source gases or one or more carrier gases.

[0292] In some embodiments, the plasma processing apparatus 1600 may include a user interface associated with the controller 1650. The user interface may include a display screen, a graphical software display of the plasma processing apparatus 1600 and / or process conditions, and user input devices such as a pointing device, a keyboard, a touch screen, a microphone, etc. Computer program code for controlling the above operations may be written in any conventional computer-readable programming language. Aspects of the controller 1650 of FIG. 16 are further explained by the above description of the controller 929 of FIG. 9.

[0293] Cleaning of High-K Dielectric Materials In some embodiments, various films other than molybdenum may be deposited during semiconductor device fabrication operations. Thin films for integrated circuit (IC) fabrication operations may include dielectric materials. The dielectric materials may include metal-containing oxides, nitrides, or carbides. For example, gate dielectrics for transistors may be formed by depositing various oxides or nitrides, such as silicon oxide (SiO2), hafnium oxide (HfO2), zirconium oxide (ZrO2), silicon oxynitride (SiON), or mixtures thereof. In addition to gate dielectrics, dielectric materials may also be used for other elements of semiconductor devices, such as metallization layers, isolation trenches, and insulating features in memory cell structures. Some of the various thin films may include dielectric materials, such as high-k dielectric materials deposited on features or substrates. Metal-containing dielectric materials may be deposited using precursors by appropriate deposition processes, such as ALD, PEALD, CVD, epitaxial growth, or PECVD. Precursors (e.g., gaseous precursors) can react to form a metal-containing layer on the substrate, but the precursors may also be transported elsewhere in the process chamber where they can be deposited as a condensed form (e.g., solid film, particles, or wall deposits). Depending on the deposition and / or sublimation temperature, the metal-containing dielectric material, once deposited on the chamber walls or other chamber components, can sublimate, transport, flake off, or redeposit on other components or surfaces within the process chamber. Redeposition of metal-containing dielectric material can occur on the substrate, thereby modifying the composition of the thin film on the substrate, creating device reliability issues, and negatively impacting manufacturing throughput. The process chamber can be periodically cleaned to remove the metal-containing dielectric material from the interior surfaces of the process chamber.

[0294] Certain criteria may be considered when designing and performing a chamber cleaning process. First, the temperature of the process chamber walls or other components being cleaned may be kept relatively low during the chamber cleaning operation to reduce potential damage to chamber components due to exposure to thermal energy and / or to reduce energy consumption. For example, maintaining the temperature of the process chamber walls consistently above 200° C. may require continuous operation of the heater, increasing the possibility of oxidation of the aluminum or aluminum-containing alloys used in the construction of the process chamber. In some embodiments, the temperature of the process chamber walls may be preferably kept between about 125 and about 200° C., or below about 200° C., during the chamber cleaning. Second, an intermediate chamber pressure range may be maintained during the chamber cleaning. Achieving a low chamber pressure may require a powerful vacuum pump, which may result in additional time required before starting the chamber cleaning operation, thereby lengthening the overall chamber cleaning cycle. High chamber pressures, especially in a non-inert environment, may result in the formation of undesirable oxides or other films on the interior surfaces of the process chamber. In some embodiments, the chamber pressure may be preferably kept between about 0.5 and about 50 Torr. Third, the etch rate of the film from the chamber components may be high enough that the duration of the entire chamber cleaning cycle is short. In some embodiments, the etch rate may be preferably about 500 to about 1,000 angstroms per minute. Fourth, the process chamber cleaning may be designed to produce volatile reaction products rather than non-volatile reaction products that would require additional cleaning operations. Fifth, the chemical or chemicals used for cleaning may be readily available and relatively low cost. Also, the chemicals may be ones that do not chemically react with the materials of the chamber walls or other components being cleaned.

[0295] Provided herein is a method for cleaning one or more dielectric materials from one or more components of a process chamber. The one or more components may include surfaces of the process chamber, pedestal, showerhead, foreline, etc. The chamber cleaning operation may include a two-part cleaning operation including (i) introducing a fluorine-containing species (such as fluorine radicals generated by a remote plasma) and (ii) introducing one or more thermal etchants to the process chamber. Thermal etching uses gas-phase reagents to react with the substrate surface and chemically and / or thermally etch material from the substrate surface. As used herein, thermal etching is also referred to as "chemical etching" and vice versa. Thermal etching can be applied across a wide range of materials. Selectivity may be desired in thermal etching reactions such that some materials are removed in the presence of other materials. Selectivity in etching has many applications in semiconductor device fabrication and surface cleaning. Selectivity in thermal etching may be high compared to other conventional etching techniques such as plasma etching or sputtering. Thermal etching generally involves a solid etching material and a gaseous etching precursor. An etch precursor (e.g., a thermal etchant) is any reactant gas in a thermal etching reaction that reacts with a solid etchant material to facilitate removal of the solid etchant material from the substrate surface. In some implementations, the etch precursor can modify a surface layer of the substrate surface, and thermal energy can be applied to etch the modified surface layer. The one or more thermal etchants may include a halide, such as a chloride or bromide compound. In a first portion, a fluorine-containing species can react with the dielectric material to generate a fluorine-containing reaction product, such as a fluoride of a metal in the dielectric material. The fluorine-containing reaction product may be non-volatile. In a second portion, the thermal etchant can react with the fluorine-containing reaction product to generate a volatile reaction product, which may be a chloride or bromide of a metal in the dielectric material. The cleaning operation may also include removing the volatile reaction product from the process chamber.In some embodiments, the metal fluoride reaction product and the thermal etchant react by a ligand exchange reaction to generate a volatile chloride or bromide of the same metal. The ligand exchange reaction may refer to a reaction in which fluorine in a metal fluoride is replaced by a halogen element to form a metal halide. The halogen element may include Br or Cl.

[0296] A two-part cleaning process according to some embodiments can reasonably meet some or all of the above criteria for a process chamber cleaning process. For example, a two-part cleaning process can involve keeping the temperature of the process chamber below about 200° C., thereby preventing high energy consumption and possible oxidation of metal components, such as aluminum-containing components and the interior walls of the process chamber. In some embodiments, the two-part cleaning process does not require low chamber pressure during the cleaning operation, thereby reducing the time for the entire cleaning cycle. For example, a two-part cleaning process can involve a chamber pressure of about 0.5 to about 100 Torr. According to some embodiments, a high etch rate (about 500 to about 1,000 angstroms per minute) can be obtained by the two-part cleaning process. Also, as described above, a two-part cleaning process can include the generation of volatile reaction products via the second part of the process (exposure of the chamber to a thermal etchant). The volatile reaction products can be relatively easily removed from the process chamber using, for example, a vacuum pump. Additionally, the thermal etchant involved in the two-part cleaning process may include a halogen element that does not react with aluminum or aluminum-containing materials that make up one or more components. Also, cleaning a process chamber with a two-part cleaning process according to some embodiments does not require significant upgrades to processing equipment that includes the process chamber.

[0297] In general, the methods disclosed herein are used to remove dielectric material from interior surfaces or other components of a process chamber. The dielectric material may include a metal-containing oxide, such as hafnium oxide, zirconium oxide, aluminum oxide, tin oxide, yttrium oxide, lanthanum oxide, or mixtures thereof. The dielectric material may include a metal-containing nitride, such as hafnium nitride, zirconium nitride, aluminum nitride, or mixtures thereof. The dielectric material may be removed by exposing the dielectric material to a fluorine-containing species and a non-fluorine halogen-containing species. The halogens may include bromine (Br) or chlorine (Cl). Reactions according to some embodiments may produce only volatile products that may be relatively easily removed from the process chamber. In some embodiments, the method is performed at a temperature of about 50 to about 650° C. FIG. 17 illustrates a flowchart of an example of removing dielectric material according to some embodiments. The operations of flowchart 100 may be performed in a different order and / or with different, fewer, or additional number of operations. In operation 110, a production process may be used to process multiple substrates in the process chamber. The production process may include depositing a dielectric film on one or more substrates by any suitable deposition route, such as ALD, PEALD, CVD, or PECVD, by flowing a chemical precursor, one or more reactants, or one or more purge gases. The dielectric film may include any of many possible metal-containing oxides. For example, the metal-containing oxide may include hafnium oxide, zirconium oxide, aluminum oxide, tin oxide, yttrium oxide, lanthanum oxide, or mixtures thereof. According to some embodiments, metal containing nitrides, carbides, oxynitrides, oxycarbides, and the like may also be deposited. For example, the metal-containing nitrides may include hafnium nitride, zirconium nitride, aluminum nitride, or mixtures thereof. During deposition on the substrate, the dielectric film may also be formed on the interior surface of the process chamber or on the surface of other components positioned in the process chamber. The dielectric film formed on the surface of the process chamber or other components may thicken due to repeated production processes in the process chamber.Although much of the description herein focuses on production processes that are deposition processes, the invention is not limited to deposition processes. Any production process that results in a dielectric film on a process chamber component can use a cleaning process as described herein. For example, a production process may include etching or otherwise removing a dielectric film from one or more substrates. The processed substrate may include one or more features formed thereon.

[0298] Operation 1710 involves processing a plurality of substrates. After each of these substrates is processed, the substrate is removed from the process chamber. For example, a transfer tool can be used to remove the substrate from the process chamber without breaking vacuum.

[0299] In operation 1720, the production process may be stopped. In some embodiments, the fabrication process of the semiconductor devices may be stopped. In some embodiments, no further wafers are processed using the production process while the process is stopped. Instead, the process chamber or components therein are cleaned to remove films formed thereon.

[0300] In operation 1730, a remote plasma having a fluorine-containing species and a Br or Cl-containing thermal etchant can be introduced into the process chamber to remove dielectric material from the interior surfaces. Although much of the description herein focuses on the use of fluorine-containing species generated by a remote plasma, the disclosed cleaning process is not limited to remote plasma sources. For example, fluorine radicals generated by any method may be used.

[0301] A process gas can be flowed into the remote plasma source and RF power can be applied to the remote plasma source to generate plasma activated species (e.g., radicals / ions) of the process gas. The process gas can include a fluorine-containing chemical. In some embodiments, a source gas for generating the plasma can include nitrogen fluoride (NF3), tetrafluoromethane (CF4), trifluoromethane (CHF3), difluoromethane (CH2F2), fluoromethane (CH3F), sulfur hexafluoride (SF6), octafluoropropane (C3F8), octafluorocyclobutane (C4F8), hexafluorocyclobutene (C4F6), 1,2,3,3,4-pentafluorocyclobuten-4-yl radical (C4F5), fluorine (F2), or a mixture thereof.

[0302] In some embodiments, the thermal etchant includes hydrogen bromide (HBr), hydrogen chloride (HCl), boron trichloride (BCl3), or mixtures thereof, or may include boron bromide (BBr3), phosphorus trichloride (PCl3), carbon tetrachloride (CCl4), nitrogen trichloride (NCl3), or mixtures thereof.

[0303] In some embodiments, the remote plasma may be generated in a remote plasma source that may be fluidly coupled to the process chamber. The remote plasma may include plasma-activated species. The plasma-activated species may include fluorine-containing species. The remote plasma source for generating the remote plasma may include inductively coupled plasma (ICP), transformer-coupled plasma (TCP), capacitively coupled plasma (CCP), microwave plasma, DC plasma, laser-produced plasma, or other plasma techniques known in the art. The plasma may be delivered from the remote plasma source into the process chamber such that the plasma-activated species are distributed toward one or more inner surfaces of the process chamber. In some embodiments, the plasma is delivered from the remote plasma source into the process chamber through a showerhead. Additionally or alternatively, the plasma is delivered from the remote plasma source into the process chamber preferably through a distributor that directs the plasma toward one or more inner surfaces of the process chamber.

[0304] In some embodiments, the fluorine-containing species and the Br or Cl-containing thermal etchant can be co-flowed into the process chamber for a predetermined time to react with and remove the dielectric material on the interior surface of the process chamber. In some embodiments, one or more fluorine-containing process gases can be flowed from a process gas supply (e.g., a first process gas supply) into the remote plasma source, where RF power is applied to the remote plasma source to generate a remote plasma containing plasma-activated species (e.g., radicals / ions) of the fluorine-containing process gas. The plasma-activated species can include the fluorine-containing species. In some embodiments, the Br or Cl-containing thermal etchant can be supplied to the remote plasma source from a process gas supply (e.g., a second process gas supply), and the remote plasma containing the fluorine-containing species and the Br or Cl-containing thermal etchant can be premixed and co-flowed in the process chamber. In another example, the remote plasma containing the fluorine-containing species and the Br or Cl-containing thermal etchant can be supplied separately to the inlet of the process chamber and mixed in the process chamber. In some embodiments, the fluorine-containing species and the thermal etchant are flowed periodically. Each cycle may include a first phase of flowing a fluorine-containing species and a second phase of flowing a thermal etchant.

[0305] In some embodiments, the remote plasma (which may generate fluorine-containing species) may not electronically activate the Br or Cl-containing thermal etchant. For example, the Br or Cl-containing thermal etchant may not mix with or react with the fluorine-containing species in the remote plasma. When introduced into the process chamber, the plasma-activated fluorine-containing species may react with the dielectric material to form fluorine-containing reaction products. For example, the metal-containing oxide may be converted to a non-volatile metal fluoride. In substantially simultaneous, co-current embodiments, the non-volatile metal fluoride may react with the Br or Cl-containing thermal etchant to generate volatile Br or Cl-containing products (e.g., metal bromides or metal chlorides). The reaction of the metal fluoride with the thermal etchant may be a ligand exchange reaction. In the case of HfO2, HfO2 may react with the fluorine-containing species to form non-volatile HfF4. HfF4 is non-volatile and may react with BCl3, Br or Cl-containing thermal etchants to generate volatile reaction products (e.g., HfCl4). During or after operation 1730, volatile reaction products may be removed from the interior surfaces of the process chamber leaving the interior surfaces free of dielectric material.

[0306] In some embodiments, a remote plasma having a fluorine-containing species and a Br or Cl-containing thermal etchant can be introduced periodically. A remote plasma including a fluorine-containing species can be first introduced into the process chamber for a predetermined time. Then, a Br or Cl-containing thermal etchant can be introduced into the process chamber for a predetermined time. Although the fluorine-containing species is introduced before the introduction of the Br or Cl-containing thermal etchant, the dielectric material (e.g., metal-containing oxide) can be removed from the interior surface of the process chamber according to a reaction sequence substantially similar to that of the co-flow embodiment described above.

[0307] In some embodiments, the periodic introduction of the remote plasma containing the fluorine-containing species and the Br- or Cl-containing thermal etchant may be optionally repeated according to a process recipe, for example, the periodic introduction may be repeated multiple times.

[0308] In some embodiments, the chamber pressure in operation 1730 may be from about 0.5 to about 100 Torr, or from about 1 to about 80 Torr. The chamber temperature may be from about 50 to about 650° C., or from about 50 to about 450° C. The etch rate of the dielectric material may be from about 500 to about 1,000 angstroms per minute.

[0309] In some embodiments, water and / or alcohol, such as methyl alcohol, ethyl alcohol, or propyl alcohol, is added in operation 1730. In the case of periodic introduction, the water or alcohol may be introduced into the process chamber separately from the introduction of the remote plasma or the Br or Cl containing thermal etchant. In the case of co-flow, the water or alcohol, the remote plasma, and the Br or Cl containing thermal etchant may be co-flowed in the process chamber. In some cases, the addition of water and / or alcohol increases the etch rate of the dielectric material.

[0310] In operation 1740, the one or more volatile reaction products may be removed from the process chamber via a vacuum pump fluidly coupled to the process chamber, thereby leaving the interior surfaces of the process chamber free of dielectric material. For example, the one or more volatile reaction products may also include O2, F2, or Cl2.

[0311] In operation 1750, one or more substrates may be optionally provided to the process chamber to resume the production process. The substrates may be transferred into the process chamber by a transfer tool for depositing a dielectric material on the features or on the substrate. The deposition process may be repeated until the thickness of the thin film, wall deposits, or particles on the interior surfaces of the process chamber exceeds a predetermined threshold.

[0312] 18 shows an example flowchart for removing dielectric material according to some embodiments. The operations of flowchart 1800 may be performed in a different order and / or with a different, fewer, or additional number of operations. Flowchart 1800 may involve a circulating flow of a fluorine-containing species and a Br- or Cl-containing thermal etchant.

[0313] In operation 1810, a remote plasma containing fluorine-containing species is introduced into the process chamber, and the dielectric material deposited on the interior surfaces of the process chamber reacts with the fluorine-containing species to generate fluorine-containing non-volatile reaction products.

[0314] In some embodiments, the time for exposing the dielectric material to the fluorine-containing species may depend on the diffusion of fluorine in the dielectric material and the chamber temperature. It should be understood that the time for introducing the fluorine-containing species or thermal etchant may be the same or substantially the same as the time for exposing the dielectric material at or on the interior surface to the fluorine-containing species or thermal etchant. In some embodiments, the reaction between the fluorine-containing species and the dielectric material may be complete when a fluorine-containing non-volatile reaction product (e.g., HfF4) is formed throughout the dielectric material to be removed. For example, a dielectric material in which fluorine diffuses slowly may require a longer exposure time to the fluorine-containing species. For a dielectric material in which fluorine diffuses quickly, a shorter exposure time may be required when introducing the fluorine-containing species into the process chamber. The exposure time may have an inverse relationship with the chamber temperature during the introduction of the fluorine-containing species. For example, a longer exposure time may be required when the chamber temperature is relatively low. In some embodiments, the dielectric material may be exposed to the fluorine-containing species for about 30 to about 300 seconds. For example, the fluorine-containing species (i.e., fluorine species) is introduced into the process chamber for about 30 to about 300 seconds.

[0315] In operation 1820, thermal etching may be performed by introducing a thermal etchant comprising Br or Cl into the process chamber, where the dielectric material deposited on the interior surfaces of the process chamber reacts with the fluorine-containing species to generate fluorine-containing non-volatile reaction products. The thermal etchant (e.g., BCl3) may be provided to the process chamber to react with the fluorine-containing non-volatile reaction products (e.g., HfF4), whereby the fluorine-containing non-volatile reaction products are converted to volatile reaction products (HfCl4). In some embodiments, the non-volatile reaction products may be exposed for about 30 to about 300 seconds. For example, the thermal etchant may be introduced into the process chamber for about 30 to about 300 seconds.

[0316] The two-step etch reaction including operations 1810 and 1820 may involve converting a non-volatile reaction product formed in operation 1810 to a volatile reaction product in operation 1820. A dielectric material such as a metal-containing oxide or metal-containing nitride may be converted to a metal-containing fluoride (e.g., a non-volatile reaction product) by exposure to a fluorine-containing species in operation 1810. In operation 1820, the fluorine ligands in the metal-containing fluoride may be replaced with another non-fluorine halogen ligand such as Br or Cl in the thermal etchant to form a reaction product that is more volatile than the metal-containing fluoride. The metal element in the metal-containing oxide (or nitride) may include hafnium, zirconium, tin, aluminum, or a mixture thereof.

[0317] In some embodiments, a single cycle including complete conversion of the dielectric coating and thermal etching is all that is required to remove the dielectric material. The fluorine-containing species can diffuse throughout the thickness of the dielectric material being removed and convert the entire thickness or substantially the entire thickness to metal fluorides. The fluorine ligands can then be replaced by Br or Cl ligands throughout the coating to form volatile reaction products to complete the etching process.

[0318] In operation 1830, operations 1810-1820 may be optionally repeated multiple times according to a process recipe. In some embodiments, the cycle including partial diffusion / conversion and thermal etching may be repeated multiple times to remove the dielectric material. Instead of completely penetrating the fluorine-containing species throughout the dielectric material to be removed, in a first cycle, the dielectric material may be exposed to the fluorine-containing species for a predetermined period of time and converted to a fluoride for subsequent thermal etching. In one or more subsequent cycles, the remaining dielectric material may undergo the same process as the first cycle until the entire dielectric material is removed from the interior surfaces of the process chamber. In one example, the etch rate for the dielectric material may be about 500 to about 1,000 angstroms per minute.

[0319] FIG. 19 illustrates an example flowchart for removing dielectric material according to some embodiments. Flowchart 1900 may relate to co-flow of a fluorine-containing species and a Br or Cl-containing thermal etchant. In operation 1910, a remote plasma including the fluorine-containing species and the Br or Cl-containing thermal etchant may be co-flowed into a process chamber. In some embodiments, the remote plasma and the thermal etchant may be introduced for about 0.1 to about 600 seconds. The co-flow according to operation 1910 may reduce the overall etch cycle time as compared to a circulating flow. In operation 1910, the formation of metal-containing fluorides (i.e., non-volatile reaction products) by the fluorine-containing species and the formation of volatile reaction products by reaction with the thermal etchant may occur substantially simultaneously. Water vapor and / or alcohol, e.g., methyl alcohol, ethyl alcohol, or propyl alcohol, may be mixed with the fluorine-containing species and the Br or Cl-containing thermal etchant to facilitate etching of the dielectric material. In operation 1920, operation 1910 may be performed multiple times according to a process recipe.

[0320] Hafnium oxide (HfOx) is an example of a metal-containing dielectric material that may be deposited on a substrate, for example, by ALD, PEALD, CVD, or PECVD using one or more hafnium-containing precursors. Hafnium oxide may be used to form a gate dielectric stack. During deposition of hafnium oxide on a substrate, it may also form as a thin film, wall deposits, or particles on the interior surfaces of a process chamber or on the surfaces of one or more components within the process chamber. Cleaning hafnium oxide deposits from the walls or components is a challenging problem.

[0321] According to some embodiments, hafnium oxide formed on the interior surfaces of a process chamber or component can react with fluorine-containing species, such as an NF3 plasma, to form hafnium tetrafluoride (HfF4) and oxygen according to the following reaction: 4F * +HfO2 → HfF4 (non-volatile) + O2 (1) The reaction product HfF4 is not volatile and may form solid particles within the process chamber or remain on the interior surfaces of the process chamber as a source of contamination. Additional actions may be required to remove the non-volatile HfF4 from the process chamber.

[0322] In some embodiments, hafnium oxide may be removed from the interior surfaces of the process chamber by reacting it with boron trichloride (BCl3) according to the following reaction: 4BCl3+3HfO2→3HfCl4(volatile)+2B2O3(2)

[0323] Reactions involving BCl3 can generate a volatile reaction product HfCl4, which can be relatively easily removed from the process chamber via the vacuum pump, while the non-volatile B2O3 can still remain in the process chamber. Thus, additional reactions may be required to avoid the formation of non-volatile B2O3 and / or conversion of non-volatile B2O3 to volatile products.

[0324] In some embodiments, HfO 2 may be exposed to a fluorine-containing species (i.e., a fluorine species or a fluorine-containing radical) and BCl 3 , and the following reactions (3) and (4) may occur: 4F * +HfO2→HfF4+O2(3a) 3HfF4+4BCl3→3HfCl4(volatile)+4BF3(3b) 12F * +3HfO2+4BCl3→3HfCl4(volatile)+4BF3+3O2(4)

[0325] In reactions (3a) and (3b), the fluorine species is introduced into the process chamber first, and BCl3 is introduced into the process chamber after the fluorine species is introduced into the process chamber. In the first step of the reaction (3a), HfO2 can react with the fluorine species to generate non-volatile HfF4. In the second step of the reaction (3b), BCl3 is provided to react with HfF4 to generate volatile HfCl4, which can be removed from the process chamber along with BF3. In reaction (4), the fluorine species and BCl3 are co-flowed in the process chamber. The co-flow of the fluorine species and BCl3 can undergo a reaction sequence similar to reaction (3) to generate volatile products, e.g., HfCl4, O2, and BF3. Regardless of the order of introduction of the fluorine species and BCl3, HfO2 has a preference to react with the fluorine species first, and then the resulting HfF4 and BCl3 can undergo a ligand exchange reaction to generate volatile HfCl4. The above reaction can be generalized to any reaction in which a metal-containing dielectric is first reacted with a fluorine species (e.g., fluorine radicals) and then the resulting metal fluoride is reacted with a chlorine- or bromine-containing species via a ligand exchange reaction to generate a volatile metal chloride or bromide.

[0326] Purpose According to some embodiments, the interior surfaces of a process chamber or surfaces of components positioned in the process chamber on which the dielectric material is deposited may be cleaned. The interior surfaces may include the interior walls of the process chamber, pedestals, showerheads, forelines, or other components that may come into contact with precursors and other reactants, thereby forming thin films, wall deposits, or particles on the interior surfaces. The dielectric material may include a metal-containing oxide or metal-containing nitride having a metal element such as hafnium, zirconium, tin, aluminum, or mixtures thereof, and may include hafnium oxide, zirconium oxide, tin oxide, yttrium oxide, lanthanum oxide, aluminum oxide, hafnium nitride, zirconium nitride, aluminum nitride, or mixtures thereof. Removal of the dielectric material according to some embodiments may involve removal of the dielectric material that may generate non-volatile reaction products by reacting a fluorine-containing species with a ligand (e.g., fluorine) in the non-volatile reaction product that can be replaced with another ligand to generate a metal compound that is more volatile than the non-volatile reaction product.

[0327] Device The apparatus of the present disclosure is configured for process chamber cleaning, such as plasma cleaning followed by thermal etching. The apparatus may be configured for other processing operations, such as deposition, development, and etching operations. In some embodiments, the apparatus is configured to perform all wet and dry etching operations. The apparatus may include multiple stations in a single wafer chamber or in the same process chamber. Using multiple stations in the same process chamber, various processing operations as described in this disclosure can be performed at different stations in the same process chamber.

[0328] The apparatus may be configured to include a remote plasma source separated from the process chamber. In some embodiments, the remote plasma source may be positioned upstream of the process chamber. The remote plasma source may be fluidly coupled to the process chamber via a showerhead to the process chamber. The remote plasma source may also be fluidly coupled to one or more gas supplies to receive one or more process gases including fluorine to generate fluorine-containing species.

[0329] The apparatus may include a process gas supply that supplies the thermal etchant to the process chamber via a gas line. In some embodiments, the process gas supply is fluidly coupled to a remote plasma source, where the thermal etchant can be mixed with a remote plasma generated at the remote plasma source, and the mixture is delivered to the process chamber. In some embodiments, the process gas supply can supply the thermal etchant directly from the process gas supply to the process chamber without mixing with the remote plasma until the thermal etchant is introduced into the process chamber. The additional gas supply may include a heater to control the temperature of the thermal etchant in the process chamber.

[0330] The apparatus may also be configured to include an exhaust system, such as a vacuum pump, to remove fluorine-containing species, thermal etchants, and reaction products from the process chamber during or after chamber cleaning.

[0331] FIG. 20 illustrates a cross-sectional view of an exemplary remote plasma system fluidly coupled to an exemplary process chamber according to some embodiments. The process chamber 2010 can include a showerhead 2020 and a pedestal 2030 for supporting a substrate including one or more features formed thereon. The pedestal 2030 can be coupled to a gate valve 2040 that can be opened to exhaust process gas and any reaction products from the process chamber 2010. The remote plasma system 2050 can include a remote plasma source 2060, where a process gas 2070 can be flowed from a first process gas supply (not shown here) and RF power is applied to the remote plasma source 2060 to generate plasma activated species of the process gas (e.g., radicals / ions of a fluorine-containing species). The process gas may include nitrogen fluoride (NF3), tetrafluoromethane (CF4), trifluoromethane (CHF3), difluoromethane (CH2F2), fluoromethane (CH3F), sulfur hexafluoride (SF6), octafluoropropane (C3F8), octafluorocyclobutane (C4F8), hexafluorocyclobutene (C4F6), 1,2,3,3,4-pentafluorocyclobuten-4-yl radical (C4F5), fluorine (F2), or mixtures thereof. The remote plasma source 2060 may include an ICP, TCP, CCP, microwave plasma, DC plasma, or laser-produced plasma. Plasma activated species generated in the remote plasma source 2060 may be supplied to the process chamber 2010 via a gas inlet 2080 fluidly coupled to the showerhead 2020. The thermal etchants described herein may be supplied from a second process gas supply (not shown here) that is fluidly coupled to the process chamber 2010 for delivering the thermal etchant to the process chamber. In some embodiments, the second process gas supply may be fluidly coupled to a remote plasma source 2050. The process chamber 2010 may also include a vacuum pump 2090 for removing process gases and reaction products from the process chamber 2010.

[0332] FIG. 21 illustrates a cross-sectional view of one station of a multi-station processing tool using an exemplary remote plasma device according to some embodiments. One station of the multi-station substrate processing tool 2100 may include a remote plasma cleaning device 2111 that may be fluidly coupled to a remote plasma source (not shown here) and a process chamber 2103. Each station may also include a showerhead 2105 and a pedestal 2107 configured to support a substrate (not shown in FIG. 21). The remote plasma cleaning device 2111 may be configured to direct plasma activated species (e.g., fluorine-containing species or fluorine species) into a volume (e.g., a microvolume) between the showerhead 2105 and the pedestal 2107. The plasma activated species may be generated in the remote plasma source by receiving a process gas as described herein from a first process gas supply (not shown here) and igniting a plasma. In some embodiments, the remote plasma cleaning device 2111 may be positioned above the showerhead 2105 to deliver fluorine-containing species in a downward direction. In some embodiments, the fluorine-containing species may be configured to deliver the fluorine-containing species in an upward direction.

[0333] In some embodiments, the fluorine-containing species may be supplied from a remote plasma source positioned upstream of the remote plasma cleaning device 2111. The fluorine-containing species may enter the process chamber 2103 of the multi-station processing tool 2100 via a process gas inlet 2109 that is fluidly coupled to a remote plasma source (not shown here). The fluorine-containing species may then be split into a substantially uniform flow 2113 on either side of the remote plasma cleaning device 2111 and transported to various locations within the process chamber 2103.

[0334] In some embodiments, the thermal etchant described herein may be supplied from a second process gas supply (not shown here) that is fluidly coupled to the process chamber 2103 for delivering the thermal etchant to the process chamber 2103. In some embodiments, the second process gas supply may be fluidly coupled to a remote plasma source.

[0335] Referring again to FIG. 7, a schematic diagram of an exemplary process station suitable for depositing a dielectric material (e.g., hafnium oxide) using ALD and / or CVD is shown. In some embodiments, either the ALD and / or CVD may be plasma enhanced. The process station 700 may be cleaned of a dielectric material, such as a metal-containing oxide or metal-containing nitride, deposited on an interior surface of a process chamber using methods provided herein. For simplicity, the process station 700 is illustrated as a stand-alone process station having a process chamber 702 for maintaining a low pressure environment. However, it will be understood that multiple process stations 700 may be included in a common process tool environment. Additionally, it will be understood that in some embodiments, one or more hardware parameters of the process station 700 (including those described in detail below) may be programmatically adjusted by one or more computer controllers.

[0336] As previously described herein, the process station 700 is in fluid communication with a reactant delivery system 701 for delivering process gases to the showerhead 706. The reactant delivery system 701 optionally includes a mixing vessel 704 for blending and / or adjusting the process gases delivered to the showerhead 706. One or more mixing vessel inlet valves 720 can control the introduction of process gases to the mixing vessel 704. Similarly, a showerhead inlet valve 705 can control the introduction of process gases to the showerhead 706. If plasma exposure is used, the plasma can be delivered to the showerhead 706 or generated in the process station 700. In some embodiments, the remote plasma can be generated from a remote plasma source outside the process station 700. The remote plasma including the fluorine species can be delivered from a remote plasma source (not shown) via a gas line (not shown) to the mixing vessel 704 and mixed with other process gases, such as the thermal etchants described herein, or other reactants, such as water vapor, methyl alcohol, ethyl alcohol, or propyl alcohol. The mixture may be introduced into the process chamber 702. In some embodiments, the remote plasma may be delivered to the process chamber 702 through a separate gas line without mixing with the thermal etchant or other reactant. In some embodiments, some or all of the remote plasma source of FIG. 20 or the remote plasma cleaning device of FIG. 21 may be fluidly coupled to the process chamber 702 to provide the remote plasma.

[0337] 7 further includes an optional vaporization point 703 for vaporizing a liquid reactant provided to the mixing vessel 704, which is fluidly coupled to the process chamber 702. For example, a thermal etchant, such as boron bromide (BBr3), phosphorus trichloride (PCl3), carbon tetrachloride (CCl4), nitrogen trichloride (NCl3), or a mixture thereof, can be vaporized at the optional vaporization point 703 before mixing with the remote plasma or before being separately provided to the process chamber. The optional vaporization point 703 can also be configured to vaporize an alcohol, such as methyl alcohol, ethyl alcohol, or propyl alcohol. In some embodiments, a liquid flow controller (LFC) can be provided upstream of the vaporization point 703 to control the mass flow rate of the liquid vaporized and delivered to the process station 700. For example, the LFC can include a thermal mass flow meter (MFM) located downstream of the LFC. The plunger valve of the LFC may then be adjusted in response to a feedback control signal provided by a proportional-integral-derivative (PID) controller in electrical communication with the MFM.

[0338] The showerhead 706 distributes process gases towards the substrate 712. In the embodiment illustrated in Figure 7, the substrate 712 is shown positioned below the showerhead 706 and resting on a pedestal 708. The showerhead 706 may have any suitable shape and may have any suitable number and arrangement of ports for distributing process gases to the substrate 712.

[0339] In some embodiments, a micro-volume 707 is located below the showerhead 706. Performing ALD and / or CVD processes in a micro-volume rather than the full volume of the process station can reduce exposure to reactants and clean-up time, reduce time to change process conditions (e.g., pressure, temperature, etc.), limit exposure of process station robots to process gases, etc. Exemplary micro-volume sizes include, but are not limited to, volumes from 0.1 liters to 2 liters. The micro-volume also impacts productivity throughput. Using a micro-volume can significantly reduce cycle times due to faster purging and higher precursor partial pressures in the micro-volume,

[0340] In some embodiments, the pedestal 708 can be raised or lowered to expose the substrate 712 to the volume between the substrate 712 and the showerhead 706. It will be appreciated that in some embodiments, the height of the pedestal can be programmatically adjusted by a suitable computer controller 750. In some embodiments, the showerhead 706 can have multiple plenum volumes with multiple temperature controls.

[0341] In some embodiments, the pedestal 708 may be temperature controlled via a heater 710. In some embodiments, the pedestal 708 may be heated to a temperature of about 50 to about 650° C., or about 50 to about 450° C. during non-plasma thermal exposure as described in disclosed embodiments. In some embodiments, the heater 710 of the pedestal 708 may include multiple independently controllable temperature control zones.

[0342] Additionally, in some embodiments, pressure control for the process station 700 may be provided by a butterfly valve (or gate valve) 718. As shown in the embodiment of Figure 7, the butterfly valve 718 throttles the vacuum provided by a downstream vacuum pump (not shown). However, in some embodiments, pressure control for the process station 700 may also be adjusted by varying the flow rate of one or more gases introduced to the process station 700.

[0343] In some embodiments, the position of the showerhead 706 can be adjusted relative to the pedestal 708 to vary the volume between the substrate 712 and the showerhead 706. Further, it will be appreciated that the vertical position of the pedestal 708 and / or the showerhead 706 may be varied by any suitable mechanism within the scope of the present disclosure. In some embodiments, the pedestal 708 may include a rotational axis for rotating the orientation of the substrate 712. It will be appreciated that in some embodiments, one or more of these exemplary adjustments may be implemented programmatically by one or more suitable computer controllers.

[0344] For example, if a plasma may be used in an operation to deposit a dielectric material on a substrate, the showerhead 706 and / or pedestal 708 are in electrical communication with a radio frequency (RF) power source 714 and a matching network 716 to provide power to the plasma. Thus, one or both of the showerhead 706 and the pedestal 708 may be provided with power for plasma generation. In some embodiments, the plasma energy may be controlled by controlling one or more of the process station pressure, gas concentration, RF source power, RF source frequency, and plasma power pulse timing. For example, the RF power source 714 and the matching network 716 may be operated at any suitable power to form a plasma having a desired composition of radical species. An example of a suitable power is up to about 1000 W.

[0345] In some embodiments, instructions for the controller may be provided via input / output control (IOC) sequence instructions. In one example, instructions for setting conditions for a process step may be included in a corresponding recipe step of a process recipe. In some cases, a process recipe step may be arranged in sequence such that all instructions for a process step are executed simultaneously with that process step. In some implementations, instructions for setting one or more process station parameters may be included in a recipe step. For example, a recipe step may include instructions for setting flow rates of one or more fluorine-containing process gases or Br- or Cl-containing thermal etchants, such as HCl, HBr, or BCl3, and time delay instructions for the recipe step. In some embodiments, the controller may include any of the features described below with respect to the system controller 850 of FIG. 8.

[0346] 8, a schematic diagram of an exemplary multi-station processing tool suitable for deposition and removal of dielectric films according to some embodiments is shown. In some embodiments, one or more hardware parameters of the process tool 800 (including those described in detail below) can be programmatically adjusted by one or more computer controllers 850.

[0347] The process stations can be configured as modules within a cluster tool. Figure 8 illustrates a semiconductor process cluster tool architecture having a vacuum integrated deposition module suitable for performing the deposition and etch operations described herein. Such a cluster process tool architecture can include a remote plasma source as described herein.

[0348] FIG. 8 also illustrates a schematic diagram of an embodiment of a multi-station processing tool 800 that includes an inbound load lock 802 and an outbound load lock 804, either or both of which may include a remote plasma source. A robot 806 is configured to move a wafer from a cassette loaded via a pod 808 at atmospheric pressure to the inbound load lock 802 via an atmospheric pressure port 810. The wafer is placed by the robot 806 on a pedestal 812 of the inbound load lock 802, the atmospheric pressure port 810 is closed, and the load lock is pumped down. If the inbound load lock 802 includes a remote plasma source, the wafer may be subjected to a remote plasma treatment to treat the substrate surface within the load lock before being introduced to the processing chamber 814. A remote plasma generated from the remote plasma source may be delivered to each process station (described below) to clean the interior surfaces according to the methods described herein. In some embodiments, the remote plasma source may be fluidly coupled to a first process gas supply (not shown here) to receive process gas from the first process gas supply, and to a second process gas supply (not shown here) to receive a thermal etchant from the second process gas supply. The second process gas supply may also be fluidly coupled to each process chamber 814. Additionally, the wafer may also be heated in the inbound load lock 802 to remove moisture and absorbed gases, for example. The chamber transfer port 816 to the processing chamber 814 is then opened, and another robot (not shown) moves the wafer into the process station and places it on the pedestal of the first station shown in the process station for processing. While the embodiment illustrated in FIG. 8 includes a load lock, it will be understood that in some embodiments, the wafer may enter the process station directly.

[0349] The illustrated processing chamber 814 includes four process stations, numbered 1 through 4 in the embodiment shown in FIG. 8. Each station has a heating pedestal (shown at 818 for station 1) and a gas line inlet. It will be appreciated that in some embodiments, each process station may have a different purpose or multiple purposes. For example, in some embodiments, a process station may be switchable between a thermal process mode and a plasma process mode. Additionally or alternatively, in some embodiments, the processing chamber 814 may include one or more corresponding pairs of thermal and plasma process stations. While the illustrated processing chamber 814 includes four stations, it will be appreciated that a processing chamber according to the present disclosure may have any suitable number of stations. For example, in some embodiments, the processing chamber may have five or more stations, while in other embodiments, the processing chamber may have three or fewer stations.

[0350] FIG. 8 illustrates one embodiment of a wafer handling system 890 for transferring wafers within the processing chamber 814. In some embodiments, the wafer handling system 890 can transfer wafers between various process stations and / or between process stations and load locks. It will be understood that any suitable wafer handling system may be used. Non-limiting examples include a wafer carousel and a wafer handling robot. FIG. 8 also illustrates one embodiment of a system controller 850 used to control the process conditions and hardware states of the process tool 800. The system controller 850 can include one or more memory devices 856, one or more mass storage devices 854, and one or more processors 852. The processor 852 can include a CPU or computer, analog and / or digital input / output connections, stepper motor controller boards, etc.

[0351] In some embodiments, the system controller 850 controls all of the activities of the process tool 800. In some embodiments, the parameters adjusted by the system controller 850 may relate to process conditions. Non-limiting examples include process gas composition and flow rates, temperature, pressure, plasma conditions (such as RF bias power levels), etc. These parameters may be provided to a user in the form of a recipe or may be entered utilizing a user interface.

[0352] In some embodiments, the system controller 850 can be configured with instructions to perform the following operations: providing a semiconductor substrate in the process chamber 814 and forming a dielectric material on one or more features on the substrate; removing the dielectric material formed on the substrate; removing the semiconductor substrate from the process chamber 814, where a dielectric material is formed on one or more interior surfaces of the process chamber 814; exposing one or more interior surfaces of the process chamber 814 to a fluorine-containing species without a semiconductor substrate in the process chamber 814 and forming a non-volatile reaction product; and exposing one or more interior surfaces of the process chamber 814 to a thermal etchant without a semiconductor substrate in the process chamber 814 and converting the non-volatile reaction product to a volatile reaction product. In some embodiments, the system controller 850 can be further configured with instructions to introduce the fluorine-containing species and the thermal etchant into the process chamber as a co-current or circulating flow. Additional aspects of the system controller 850 of FIG. 8 have been previously described herein and will not be repeated here. The controllers described above with respect to any of FIG. 7, FIG. 8, FIG. 20, or FIG. 21 can be implemented using the tool of FIG. 8.

[0353] Preventing aluminum fluoride redeposition on showerheads during cleaning In some embodiments, semiconductor device fabrication typically involves various deposition processes that deposit one or more silicon-containing films to form integrated circuits and related devices by various methods including CVD, PECVD, ALD, or PEALD. As a result of the deposition process, one or more silicon-containing materials are deposited on the substrate on which the various materials are deposited, as well as on the interior surfaces of the process chamber in which the deposition process occurs. As a result, films from various materials are formed on the interior surfaces of the process chamber, and the materials can accumulate over time to form deposition by-products. The deposition by-products can include silicon-based materials, such as silicon oxide, silicon carbide, or silicon nitride. The deposition by-products can dissolve, peel, thermally desorb, or evaporate through subsequent processes in the process chamber, causing contamination of the substrate or features formed on the substrate. This contamination is one reason for low production yield / throughput, or device reliability issues. The deposition by-products that accumulate on the interior surfaces of the process chamber are periodically removed to avoid contamination of the process chamber.

[0354] One method of removing contaminants in a process chamber is to introduce a plasma flow containing fluorine (F)-containing species. For this type of cleaning, one or more source gases (e.g., cleaning gases) may be used, including nitrogen fluoride (NF3), carbon tetrafluoride (CF4), carbon hexafluoride (CF6), octafluoropropane (CF8), and other fluorine-containing compounds (i.e., fluorine-containing reactants). The one or more source gases may be supplied to a plasma source. The plasma source may be an inductively coupled plasma reactor, a capacitively coupled plasma reactor, a microwave plasma reactor, a DC plasma reactor, or a laser-produced plasma reactor. The plasma flow generated from the plasma source may flow into the process chamber and clean the interior surfaces of the process chamber. The plasma flow may include fluorine-containing species (including fluorine-based radicals), oxygen-containing species (including oxygen-based radicals), and an inert gas. Examples of such F-containing cleaning processes are described above with reference to Figures 12-21.

[0355] Aluminum fluoride may be formed on surface regions of interior components or walls made of aluminum or aluminum-containing materials by reaction between aluminum and fluorine-containing species introduced for plasma cleaning. Aluminum fluoride may be deposited on the walls at low temperatures and may thermally desorb above about 450° C. Aluminum fluoride may be aluminum trifluoride (AlF3) and may cause contamination of the substrate or substrate features in subsequent processes. In some cases, aluminum trifluoride may be a gaseous contaminant that diffuses into the showerhead and may be deposited / adsorbed on the showerhead, thereby causing contamination of the substrate or substrate features in subsequent processes.

[0356] An aspect of the embodiment relates to a method of cleaning a process chamber by providing a plasma flow into the process chamber at a predetermined temperature as described herein. The plasma source is fluidly coupled to the process chamber via a showerhead. The plasma flow may have a flow rate sufficient to prevent diffusion of gaseous contaminants from reaching one or more locations of the process chamber. The plasma flow from the plasma source may include a fluorine-containing species. The fluorine-containing species in the plasma flow may react with deposition by-products and remove the deposition by-products from the interior surfaces of the process chamber. As a result of the reaction between the fluorine-containing species and the deposition by-products, gaseous by-products may be generated. The gaseous by-products may be removed from the process chamber.

[0357] Another aspect of the embodiment relates to a method for preventing contamination of a showerhead in a process chamber by introducing a plasma flow including a fluorine-containing species. While the fluorine-containing species removes silicon-based deposition products from the interior surfaces of the process chamber, the fluorine-containing species may react with aluminum in aluminum-containing components to form aluminum fluorides, such as aluminum trifluoride (AlF3). By maintaining the process chamber temperature at a predetermined temperature, the aluminum fluoride may thermally desorb from the surface into the gas phase. A sufficient flow rate of the plasma flow may prevent the gaseous aluminum fluoride from reaching the surface of the showerhead, keeping the showerhead surface substantially free of aluminum fluoride. Chamber cleaning and prevention of showerhead contamination may be achieved by providing a plasma flow according to some embodiments. This may occur at a predetermined temperature. A substrate may be transported into the chamber for film deposition at a predetermined temperature without modifying the process chamber temperature.

[0358] Referring again to FIG. 16, a schematic diagram of an exemplary plasma processing apparatus according to some embodiments is shown. It will be understood that the plasma processing apparatus of FIG. 16 can be used to deposit a film by ALD, PEALD, CVD, or PECVD, and / or to clean a process chamber by delivering a plasma flow, according to some embodiments. Process chamber (or "chamber") cleaning of the present disclosure can include delivering a plasma flow containing fluorine-containing species to remove deposition by-products from one or more surface regions of an inner part or surface of the plasma processing apparatus, and to limit the diffusion of gaseous contaminants from a particular location in the process chamber. In some embodiments, the apparatus of FIG. 16 can be used to deposit a film by remote plasma CVD, and can also be used to clean a process chamber by providing a plasma flow containing fluorine-containing species.

[0359] According to some embodiments, a plasma flow generated from a remote plasma source may be delivered into the process chamber after the substrate is removed from the process chamber. The process chamber may be maintained at a predetermined temperature. A plasma flow including a fluorine-containing species may be delivered at a flow rate sufficient to clean the interior surface of the process chamber by reacting with deposition by-products while substantially preventing gaseous contaminants (e.g., gaseous aluminum fluoride) in the process chamber from redepositing on the surface of the showerhead in the process chamber. As a result, the showerhead surface may be maintained substantially aluminum fluoride-free. The substrate may be transported into the process chamber for depositing a film on the substrate. The deposition of the film on the substrate may occur before or after the chamber cleaning. The chamber cleaning (including prevention of showerhead contamination) and the film deposition may be performed consecutively without changing the process chamber temperature and / or without exposing the substrate to the ambient atmosphere. In some embodiments, the chamber cleaning and the film deposition may be repeated without changing the process chamber temperature. The process chamber temperature may be the temperature in the environment adjacent to the substrate. In some cases, the process chamber temperature corresponds to the pedestal temperature.

[0360] The plasma processing apparatus 1600 of FIG. 16 includes a remote plasma source 1602 separated from a process chamber 1604. The remote plasma source 1602 is fluidly coupled to the process chamber 1604 via a gas distributor or showerhead 1606. A coil 1628 may be disposed around the remote plasma source 1602, which includes an outer wall (e.g., a ceramic dome). In some embodiments, the remote plasma source 1602 includes an outer wall including a ceramic material that is resistant to fluorine-containing species. The outer wall may be semicircular or elliptical in shape. In some embodiments, the outer wall may be made of a ceramic material. The coil 1628 is electrically coupled to a plasma generator controller 1632, which may be used to form and maintain a plasma in a plasma region 1634 via inductively coupled plasma generation, capacitively coupled plasma generation, microwave plasma generation, DC plasma generation, or laser-produced plasma generation. In some embodiments, the plasma generator controller 1632 may include a power source for supplying power to the coils 1628, which may range from about 500 watts (W) to about 15 kilowatts (kW) per station, or from about 2 kW to about 10 kW per station during plasma generation. In some embodiments, it is possible to generate a continuous supply of radicals via plasma excitation using electrodes or antennas for parallel plate plasma generation, inductively coupled plasma generation, capacitively coupled plasma generation, microwave plasma generation, DC plasma generation, or laser-produced plasma generation. In some embodiments, the radicals and / or ions may be generated by inductively coupled plasma generation. In some embodiments, the radicals and / or ions may be generated by microwave plasma, direct current (DC) plasma, or laser-produced plasma. Regardless of the mechanism used to ignite and sustain the plasma in the plasma region 1634, radical species may be continuously generated using plasma excitation.

[0361] A supply of ions and radicals may be continuously generated in the plasma region 1634 while one or more source gases are supplied to the remote plasma source 1602. The ions generated in the plasma region 1634 may be filtered by an ion filter in the showerhead 1606. In this manner, the radicals generated in the plasma region 1634 may be supplied to the substrate 1612 in the process chamber 1604 while limiting ion bombardment. Conditions within the remote plasma source 1602, including the composition of the source gases supplied to the remote plasma source 1602 and the RF power supplied to the coil 1628, may be controlled to optimize the generation of desired radical species in the plasma region 1634.

[0362] 16, a source gas supply 1636 is fluidly coupled to the remote plasma source 1602 to supply a source gas. In some embodiments, the one or more source gases may include an oxygen-containing reactant such as oxygen (O2), carbon dioxide (CO2), or nitrogen dioxide (NO2), a fluorine-containing reactant such as nitrogen trifluoride (NF3), fluorine (F2), carbon tetrafluoride (CF4), or carbon hexafluoride (C2F6), a hydrogen-containing reactant such as hydrogen (H2) or methane (CH4), an inert gas such as argon (Ar), or a nitrogen-containing reactant such as nitrogen (N2), ammonia (NH3), diazene (N2H2), or hydrazine (N2H4), a carbon-containing reactant such as acetylene (C2H2) or propene (C3H6), or a mixture thereof.

[0363] It should be understood that the mixture of source gases for film deposition may not be the same as the mixture of source gases for chamber cleaning. The deposited film may be a silicon-based film including doped or undoped silicon carbide, for example, oxygen-doped silicon carbide (SiCO), nitrogen-doped silicon carbide (SiCN), and nitrogen- and oxygen-doped silicon carbide (SiOCN). In many cases, doped silicon carbide has up to about 50% dopant atoms, regardless of whether the dopant atoms are oxygen, nitrogen, or atoms of another element. The doping level provides the desired film properties. Silicon-based films may also include silicon oxide (SiOx), silicon nitride (SixNy), or oxygen-doped silicon nitride (SiON). The gas mixture supplied to the remote plasma source for the film deposition process may include, but is not limited to, oxygen (O2), carbon dioxide (CO2), nitrogen dioxide (NO2), hydrogen (H2), methane (CH4), argon (Ar), nitrogen (N2), ammonia (NH3), diazene (N2H2), hydrazine (N2H4), acetylene (C2H2), propene (C3H6), or mixtures thereof.

[0364] The gas mixture for cleaning the chamber may include a fluorine-containing gas, such as nitrogen trifluoride (NF3), fluorine (F2), carbon tetrafluoride (CF4), or carbon hexafluoride (C2F6). For example, the gas mixture may include, but is not limited to, nitrogen trifluoride (NF3), fluorine (F2), oxygen (O2), carbon dioxide (CO2), nitrogen dioxide (NO2), hydrogen (H2), argon (Ar), nitrogen (N2), or mixtures thereof.

[0365] The type of radical species generated in the remote plasma source 1602 may be determined by the source gas supplied to the remote plasma source 1602. In some embodiments, depending on the nature of the source gas, hydrogen radicals (H * ), nitrogen radical (N * ), oxygen radical (O * ), fluorine radical (F * ), amine radical (NH * , NH2 * ), carbon radical (C* ), or a mixture of radical species including mixtures thereof, may be generated in the plasma region 1634 under near steady-state conditions during steady-state film deposition or chamber cleaning controlled by the plasma generator controller 1632, although transients may occur at the beginning and end of the film deposition and / or chamber cleaning.

[0366] An additional gas supply 1638 is fluidly coupled to the remote plasma source 1602 to supply one or more additional gases. Although the embodiment of FIG. 16 illustrates the gas mixture of the source gas and the one or more additional gases being introduced through separate gas outlets, it will be understood that the gas mixture may be introduced directly into the remote plasma source 1602. That is, a premixed dilute gas mixture may be supplied to the remote plasma source 1602 through a single gas outlet. The one or more additional gases may include a carrier gas. Non-limiting examples of the additional gases may include helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and nitrogen (N2). The one or more additional gases may support or stabilize steady-state plasma conditions in the remote plasma source 1602 or assist in the ignition or extinction process of a transient plasma.

[0367] In some embodiments, the gas conduits from a gas source (not shown) through the source gas supply 1636 to the remote plasma source 1602 and / or the gas conduits from a gas source (not shown) through an additional gas supply 1638 to the remote plasma source 1602 may be designed to withstand high gas flow rates according to some embodiments.

[0368] In some embodiments, a co-reactant that is not the main silicon-containing precursor or hydrogen radicals is introduced during the deposition reaction. In some embodiments, the plasma processing apparatus is configured to introduce the co-reactant through the source gas supply 1636 or the additional gas supply 1638, where the co-reactant is at least partially converted to plasma. Examples of such co-reactants include carbon dioxide (CO2), carbon monoxide (CO), water (H2O), methanol (CH3OH), oxygen (O2), ozone (O3), nitrogen (N2), nitrous oxide (N2O), ammonia (NH3), diazene (N2H2), methane (CH4), ethane (C2H6), acetylene (C2H2), ethylene (C2H4), diborane (B2H6), and mixtures thereof. Such materials may be used as nitriding agents, oxidizing agents, reducing agents, and the like.

[0369] Plasma activated species 1642, such as excited nitrogen, hydrogen, carbon, oxygen, fluorine, and / or amine radicals, flow from the remote plasma source 1602 and through the showerhead 1606 into the process chamber 1604. In some embodiments, the plasma activated species 1642 may be a plasma stream. The plasma activated species 1642 in the showerhead 1606 and in the process chamber 1604 generally do not undergo continuous plasma excitation therein. The showerhead 1606 may have multiple gas ports that diffuse the flow of plasma activated species 1642 into the process chamber 1604. In some embodiments, the multiple gas ports may be spaced apart from one another. In some embodiments, the multiple gas ports may be arranged as an array of regularly spaced channels or through holes that extend through a plate that separates the remote plasma source 1602 and the process chamber 1604. The multiple gas ports can smoothly disperse and diffuse the existing radicals (including plasma activated species 1642) from the remote plasma source 1602 into the deposition zone 1610 of the process chamber 1604 while filtering out the ions. Upon passing through the multiple gas ports in the showerhead 1606, the plasma activated species 1642 (i.e., the plasma flow) can further flow in a downward direction, or substantially in a downward direction. In some embodiments, the plasma flow can include fluorine-containing species and other plasma activated species.

[0370] One or more silicon-containing precursors 1644 (or other process gases) can be introduced into the process chamber 1604 to deposit a silicon-based film by delivering plasma activated species 1642 from the showerhead 1606 to the process chamber 1604. The silicon-containing precursors 1644 can be introduced through a gas outlet 1608, which can be fluidly coupled to a silicon-containing precursor source 1640. The gas outlet 1608 can include openings spaced apart from one another such that a flow of the silicon-containing precursors 1644 can be introduced in a direction parallel to the plasma activated species 1642 flowing from the showerhead 1606. In some embodiments, the gas outlet 1608 can be located downstream of the showerhead 1606. In some embodiments, the gas outlet 1608 is part of the showerhead 1606, such as a dual plenum showerhead. The dual plenum showerhead may provide separate outlets / pathways for the plasma activated species 1642 and the silicon-containing precursor 1644 to avoid mixing within the showerhead 1606. In this way, the silicon-containing precursor 1644 can flow through the showerhead 1606 into the process chamber 1604 without being exposed to the plasma in the remote plasma source 1602. The gas outlet 1608 may be located upstream of the deposition zone 1610 and the substrate 1612. The deposition zone 1610 is located inside the process chamber 1604 between the gas outlet 1608 and the substrate 1612. In some embodiments, a plasma may be formed directly within the process chamber. To generate a direct plasma, in some embodiments, a plasma processing apparatus may be provided or modified to include an upper electrode, a lower electrode, and an RF generating system that generates and outputs an RF voltage to one of the upper and lower electrodes, while the other of the upper and lower electrodes may be grounded or floated. In some embodiments, the RF generating system may include an RF voltage generator and a matching network. The direct plasma may include fluorine-containing species and other plasma-activated species. In some embodiments, the direct plasma may be formed at a location near the showerhead.

[0371] In some embodiments, the silicon-containing precursor may include at least one or more Si-Si bonds and / or at least one or more Si-H bonds.Silicon-containing precursors suitable for use according to the disclosed embodiments may include silane (SiH4), disilane (Si2H6), and organosilanes such as methylsilane, ethylsilane, isopropylsilane, t-butylsilane, dimethylsilane, diethylsilane, di-t-butylsilane, allylsilane, sec-butylsilane, thexylsilane, isoamylsilane, t-butyldisilane, and di-t-butyldisilane.

[0372] In some embodiments, the silicon-containing precursor can also include a halosilane. A halosilane includes at least one halogen group, and may or may not include hydrogen and / or carbon groups. Examples of halosilanes are iodosilane, bromosilane, chlorosilane, and fluorosilane. Specific chlorosilanes include tetrachlorosilane, trichlorosilane, dichlorosilane, monochlorosilane, chloroallylsilane, chloromethylsilane, dichloromethylsilane, chlorodimethylsilane, chloroethylsilane, t-butylchlorosilane, di-t-butylchlorosilane, chloroisopropylsilane, chloro-sec-butylsilane, t-butyldimethylchlorosilane, thexyldimethylchlorosilane, and the like.

[0373] In some embodiments, the silicon-containing precursor can also include aminosilane. Aminosilanes contain at least one nitrogen atom bonded to a silicon atom, but can also contain hydrogen, oxygen, halogen, and carbon. Examples of aminosilanes include monoaminosilane, diaminosilane, triaminosilane, and tetraaminosilane (H3Si(NH2), H2Si(NH2)2, HSi(NH2)3, and Si(NH2)4, respectively), and substituted monoaminosilane, diaminosilane, triaminosilane, and tetraaminosilane, such as t-butylaminosilane, methylaminosilane, tert-butylsilane amine, bis(tert-butylamino)silane (SiH2(NHC(CH3)3)2(BTBAS), Diisopropylaminosilane (DIPAS), tert-butylsilylcarbamate, SiH(CH3)-(N(CH3)2)2, SiHCl-(N(CH3)2)2, (Si(CH3)2NH)3, and the like. A further example of an aminosilane is trisilylamine (N(SiH3)). In some embodiments, aminosilanes with two or more amine groups attached to a central Si atom may be used. These may be less damaging than aminosilanes with only a single amine group attached.

[0374] Further examples of silicon-containing precursors include trimethylsilane (3MS), ethylsilane, butasilane, pentasilane, octasilane, heptasilane, hexasilane, cyclobutasilane, cycloheptasilane, cyclohexasilane, cyclooctasilane, cyclopentasilane, 1,4-dioxa-2,3,5,6-tetrasilacyclohexane, diethoxymethylsilane (DEMS), diethoxysilane (DES), dimethoxymethylsilane, dimethoxysilane. Examples of suitable silanes include diphenyl ether (DMOS), methyldiethoxysilane (MDES), methyldimethoxysilane (MDMS), octamethoxydodecasiloxane (OMODDS), tert-butoxydisilane, tetramethylcyclotetrasiloxane (TMCTS), tetraoxymethylcyclotetrasiloxane (TOMCTS), triethoxysilane (TES), triethoxysiloxane (TRIES), and trimethoxysilane (TMS or TriMOS).

[0375] In addition to the silicon-containing precursor, the environment adjacent to the substrate may include one or more radical species, preferably in a substantially low-energy state. The radicals may include hydrogen radicals, nitrogen radicals, oxygen radicals, amine radicals, carbon radicals, or mixtures thereof. In some embodiments, all, substantially all, or a significant portion of the hydrogen atom radicals may be in a ground state, for example, at least about 90% or about 95% of the hydrogen atom radicals adjacent to the substrate may be in a ground state. In some implementations, when the excited hydrogen atom radical loses energy or relaxes, the excited hydrogen atom radical may become a substantially low-energy state hydrogen atom radical or a ground state hydrogen atom radical. The hydrogen atom radical in a substantially low-energy state or ground state may be capable of selectively breaking Si-H bonds and Si-Si bonds, generally while retaining Si-O, Si-N, and / or Si-C bonds. In some implementations, process conditions may be provided such that the excited hydrogen atom radical loses energy or relaxes to form a substantially low-energy state or ground state hydrogen atom radical.

[0376] In a film deposition process, a significant portion of the silicon-containing precursor 1644 can be prevented from mixing with the plasma activated species 1642 in or adjacent to the showerhead 1606. In some embodiments, the silicon-containing precursor 1644 can be delivered to the substrate 1612 in a dosing phase of an ALD cycle separately from the plasma activated species 1642 delivered to the substrate 1612 during the plasma exposure phase of the ALD cycle. The adsorbed silicon-containing precursor 1644 can react with radicals of the plasma activated species 1642 during the plasma exposure phase of the ALD cycle to deposit a film. In some embodiments, the silicon-containing precursor 1644 can be delivered to the substrate 1612 continuously to interact with the plasma activated species 1642 in the deposition zone 1610 to deposit a film by CVD. The radicals of the plasma activated species 1642 can mix with the silicon-containing precursor 1644 in the gas phase during the CVD formation of the film.

[0377] The gas may be removed from the process chamber 1604 via an outlet 1648 that is fluidly coupled to a pump (not shown). Thus, the radical species or the purge gas may be removed from the process chamber 1604.

[0378] The substrate 1612 is supported on a substrate support structure or wafer pedestal (i.e., pedestal) 1614. The pedestal 1614 may be configured with lift pins or other movable support members to position the substrate 1612 within the deposition zone 1610. The substrate 1612 may be moved to a position closer to or further from the showerhead 1606. The pedestal 1614, in some embodiments, can also regulate the temperature of the substrate 1612, which can provide some selective control over thermally activated surface reactions on the substrate 1612.

[0379] The pedestal 1614 may be provided with a ceramic material. In one embodiment, the pedestal 1614 may be made of aluminum nitride, which may be suitable for high temperature processes, such as plasma processing environments, without causing thermal damage to the pedestal 1614. Other surfaces of the process chamber 1604 may be formed of a ceramic material, such as aluminum nitride.

[0380] In some embodiments, the pedestal 1614 includes an electrostatic chuck 1616. The electrostatic chuck 1616 may include one or more electrostatic clamping electrodes 1618 embedded within the body of the electrostatic chuck 1616. In some embodiments, the one or more electrostatic clamping electrodes 1618 may be coplanar or substantially coplanar. The electrostatic clamping electrodes 1618 may be powered by a DC power source or a DC chucking voltage (e.g., about 200 V to about 2000 V) such that the substrate 1612 may be held on the electrostatic chuck 1616 by electrostatic attraction. Power to the electrostatic clamping electrodes 1618 may be provided via a first electrical wire 1620. The electrostatic chuck 1616 may further include one or more heating elements 1622 embedded within the body of the electrostatic chuck 1616. The one or more heating elements 1622 may include resistive heaters. In some embodiments, the one or more heating elements 1622 are positioned below the one or more electrostatic clamping electrodes 1618. The one or more heating elements 1622 may be configured to heat the substrate 1612 to a temperature greater than about 450° C., greater than about 500° C., greater than about 550° C., greater than about 600° C., or greater than about 650° C. The one or more heating elements 1622 provide selective temperature control to the substrate 1612. Power to the one or more heating elements 1622 may be supplied via a second electrical wire 1624.

[0381] In some embodiments, a heat shield (not shown) may be positioned below the pedestal 1614. The heat shield acts as insulation below the pedestal 1614 to mitigate heat loss due to thermal radiation, thereby reducing the amount of power required to maintain the pedestal 1614 at a particular elevated temperature, and also prevents overheating of other components in the process chamber 1604 due to excess heat radiating from the pedestal 1614. For example, the heat shield may be radially offset from the stem 1626 and may have a thin, annular-shaped body with a high view factor relative to the underside of the electrostatic chuck 1616. Thus, the annular-shaped heat shield may reduce radiative heat loss from the pedestal 1614.

[0382] The controller 1650 may include instructions for controlling process conditions for operation of the plasma processing apparatus 1600. The controller 1650 typically includes one or more memory devices and one or more processors. The processor may include a CPU or computer, analog and / or digital input / output connections, stepper motor controller boards, etc. Instructions for performing appropriate control operations are executed on the processor. These instructions may be stored in a memory device associated with the controller 1650 or provided over a network.

[0383] In certain embodiments, the controller 1650 controls all or most of the activities of the plasma processing apparatus 1600 described herein. For example, the controller 1650 can control all or most of the activities of the plasma processing apparatus 1600 associated with film deposition and / or chamber cleaning. In some embodiments, the controller 1650 includes a processor system 1652 (e.g., a microprocessor) configured to execute instructions held in a data system 1654 (e.g., a memory). In some embodiments, the controller 1650 can communicate with the plasma generator controller 1632 and control plasma parameters and / or conditions in the remote plasma source 1602. In some embodiments, the controller 1650 can communicate with the pedestal 1614 and control the pedestal height (substrate position), electrostatic chucking and dechucking, and temperature. In some embodiments, the controller 1650 can control other process conditions, such as RF power settings, frequency settings, duty cycle, pulse time, pressure in the process chamber 1604, pressure in the remote plasma source 1602, gas composition and gas flow rates from the source gas supply 1636, gas composition and gas flow rates from the additional gas supply 1638 and other sources, the temperature of the pedestal 1614, and the temperature of the process chamber 1604, among other process conditions.

[0384] In some embodiments, the controller 1650 may include instructions configured to perform operations such as heating the process chamber 1604 to a predetermined temperature, delivering a plasma effluent from the remote plasma source 1602 to the process chamber 1604 through the showerhead 1606, and limiting gaseous contaminants from the showerhead 1606. In some embodiments, the plasma effluent includes a fluorine-containing reactant, such as nitrogen trifluoride. For example, the plasma effluent includes an oxygen-containing species (including oxygen-based radicals), a fluorine-containing species (e.g., fluorine-based radicals), and an inert gas. The inert gas may include nitrogen, argon, helium, neon, krypton, or mixtures thereof. In some embodiments, the predetermined temperature may range from about 450° C. to about 650° C.

[0385] In some embodiments, the controller 1650 may include instructions configured to perform operations such as introducing a first dose of a silicon-containing precursor 1644 in the gas phase to adsorb onto the substrate 1612 and exposing the substrate 1612 to plasma activated species 1642 of a source gas generated by the remote plasma source 1602, where the adsorbed silicon-containing precursor 1644 reacts with the plasma activated species 1642 to deposit a silicon-containing film. In some embodiments, the controller 1650 may include instructions configured to perform operations such as setting a chamber pressure in the process chamber 1604 to between 0.6 Torr and about 30 Torr, or between about 1 Torr and about 30 Torr, and setting a substrate temperature to a high temperature between about 200° C. and about 700° C. In some embodiments, the controller 1650 may include instructions configured to perform operations such as applying a first voltage to the electrostatic chuck 1616 of the pedestal 1614 to electrostatically clamp the substrate 1612 in the process chamber 1604, reversing the polarity of the first voltage applied to the electrostatic chuck 1616, applying a second voltage to the electrostatic chuck 1616 that is lower than the first voltage, reversing the polarity of the second voltage applied to the electrostatic chuck 1616, and removing the substrate 1612 from the electrostatic chuck 1616. In some embodiments, the controller 1650 may include instructions configured to perform chamber cleaning using a plasma flow including a fluorine-containing reactant, and film deposition on the substrate 1612 using a silicon-containing precursor 1644 and plasma activated species 1642.

[0386] In some embodiments, the plasma processing apparatus 1600 may include a user interface associated with the controller 1650. The user interface may include a display screen, a graphical software display of the plasma processing apparatus 1600 and / or process conditions, and user input devices such as a pointing device, a keyboard, a touch screen, a microphone, etc. Computer program code for controlling the above operations may be written in any conventional computer-readable programming language. Additional aspects of the controller 1650 have been described herein above and will not be repeated here.

[0387] In some embodiments, depending on the process recipe, the process chamber for the exemplary plasma processing apparatus may be used to deposit a thin layer by any suitable deposition method, such as ALD, PEALD, CVD, or PECVD, in accordance with embodiments herein, and / or to clean the interior surfaces of the process chamber.

[0388] In some embodiments, the process chamber may include a remote plasma source positioned at an upper portion of the process chamber. The remote plasma source may be a dome or may include a coil around the remote plasma source. The remote plasma source may include a plasma region within the remote plasma source. The remote plasma source may be fluidly coupled to the process chamber through a showerhead.

[0389] In some embodiments, the source gas inlet may be positioned at the top of the remote plasma source, while the source gas inlet may be positioned elsewhere in the remote plasma source. The source gas inlet may be fluidly coupled to the remote plasma source and may provide one or more source gases from one or more gas sources to the remote plasma source. Radical species, such as nitrogen radicals, fluorine radicals, hydrogen radicals, oxygen radicals, argon radicals, carbon radicals, or mixtures thereof, may be generated in the plasma region to form a plasma flow. In some embodiments, if chamber cleaning is required, a plasma flow including fluorine radicals may be generated. The plasma flow may flow in a downward or substantially downward direction through multiple gas ports in the showerhead. As used herein, a downward or substantially downward direction may refer to a direction perpendicular or substantially perpendicular to the main plane of the showerhead. The plasma flow may further flow down toward a pedestal spaced a predetermined distance from the showerhead.

[0390] In some embodiments, the pedestal may include one or more heating elements embedded within or thermally coupled to the pedestal. The heating elements may be coupled to a controller and configured to heat a substrate supported on the pedestal to a temperature suitable for a process, such as film deposition. The heating elements may be operable even when there is no substrate in the process chamber. The process chamber may further include an outlet for removing any gas from the process chamber.

[0391] In some embodiments, the controller may be coupled to one or more gas sources to control the flow rate of one or more source gases entering the remote plasma source. In some embodiments, the flow rate of the plasma flow through the showerhead may be proportional to the flow rate of the source gas. As the flow rate of the source gas increases, the flow rate of the plasma flow may also increase. In some embodiments, the plasma flow through the showerhead may form a plasma volume that extends from the showerhead to the pedestal. Depending on the surface area of ​​the showerhead and the pedestal, the entire surface of the pedestal may be exposed to the plasma volume. If the plasma flow includes fluorine-containing species, the material deposited on the pedestal may react with the incoming flow of fluorine-containing species. In some embodiments, depending on the flow rate of the source gas (and the corresponding plasma flow), the plasma flow contacting the surface of the pedestal may move the gas flow adjacent to the pedestal to other locations in the process chamber.

[0392] FIG. 22 shows a process flow diagram 2200 for cleaning a process chamber according to some embodiments. The process flow diagram 2200 describes some embodiments for cleaning the interior surfaces of a process chamber to remove chamber contamination, followed by deposition of a substantially contaminant-free film, such as a silicon-based film. The process chamber cleaning may include delivering a high flow rate of plasma flow containing fluorine-containing species into the process chamber and restricting the flow of contaminants from certain locations in the process chamber. For example, the high flow rate of plasma flow containing fluorine-containing species restricts the flow of contaminants from the showerhead. The two processing steps of cleaning the process chamber and depositing the silicon-based film may be performed without substantially changing the process chamber temperature and / or the process chamber pressure. In this manner, the chamber cleaning and deposition may be performed without introducing an air break between operations. In some embodiments, the process chamber cleaning and film deposition are performed while the process chamber temperature is maintained at a predetermined temperature.

[0393] A semiconductor fabrication process includes a cleaning process that removes films deposited on the interior surface or surface area of ​​the interior components of the process chamber by supplying one or more etching compositions to the interior of the process chamber after a predetermined number of depositions. The etching composition can include, for example, fluorine-containing species that can react with the silicon-containing film on the wall and dissociate into gaseous etching by-products. The process chamber includes an interior component or interior surface made of aluminum, including aluminum, anodized aluminum, and alloy or ceramic materials. In some embodiments, the fluorine-containing species in the etching composition can also react with aluminum to form aluminum fluoride on the surface of the aluminum-containing component.

[0394] Aluminum fluoride may be gaseous or condensed depending on the temperature at which it is formed. Aluminum fluoride may thermally desorb from the pedestal at about 450° C. or higher, be transported elsewhere in the process chamber, and redeposit elsewhere in a condensed form (e.g., solid film or particles), thereby creating another source of contamination. Redeposition may occur on surface areas of internal components or interior surfaces of the process chamber. One internal component may be the showerhead. Aluminum fluoride may travel toward the showerhead and redeposit on the showerhead surface. For example, needle-shaped aluminum fluoride flakes may form on the showerhead.

[0395] The redeposited aluminum fluoride is undesirable because it may be inadvertently deposited on one or more features of the semiconductor substrate in a subsequent process. During a subsequent deposition or other substrate process, the gaseous aluminum fluoride or a mixture of gaseous aluminum fluoride and other reactants may be adsorbed on the features on the substrate. This may, for example, modify the electrical properties or chemical composition of the film deposited in the subsequent deposition. As a result, the semiconductor device may experience reliability issues due to undesirable impurities or may not function properly as designed. The redeposited aluminum fluoride on the process chamber walls may flake off and fall onto the floor or other parts of the process chamber, which may be one source of chamber contamination.

[0396] Removing aluminum fluoride from process chamber surfaces may require additional steps, including but not limited to cooling, disassembly, and cleaning of the process chamber. Additionally, aluminum fluoride deposits are relatively difficult to remove. These additional steps can contribute to slow processing times and associated reduced throughput.

[0397] Prior to operation 2202, the substrate may be transferred out of the process chamber. Prior to removing the substrate, one or more films may be deposited on the substrate at a predetermined temperature. The process chamber temperature may be controlled by operating one or more heating elements in the pedestal or electrostatic chuck supporting the substrate. In some embodiments, the process chamber temperature may be substantially the same as the substrate temperature. In some embodiments, the process chamber temperature may range from about 450° C. to about 650° C., or from about 500° C. to about 600° C., or from about 530° C. to about 570° C. The process chamber temperature may be maintained until the chamber cleaning is completed. The one or more films may be silicon-based layers. For example, the silicon-based layer may include silicon oxide, silicon carbide, silicon oxycarbide, silicon carbonitride, or silicon oxycarbonitride. During the one or more film depositions, a film may also be formed on the interior surfaces of the process chamber. For example, the film may form on the interior walls, forming a deposition by-product that may accumulate with deposition time. For example, deposition by-products can include silicon, such as silicon oxide, silicon carbide, or silicon nitride.

[0398] If the process chamber temperature is below the predetermined temperature (e.g., the process chamber is not operating), the process chamber temperature may be increased to the predetermined temperature in operation 2202. In some embodiments, the predetermined temperature may be determined based on a temperature above which the metal fluoride thermally desorbs. For example, aluminum fluoride may evaporate at temperatures above about 450° C., and the predetermined temperature may range from about 450° C. to about 650° C., or from about 500° C. to about 600° C., or from about 530° C. to about 570° C. In some embodiments, the process chamber temperature may be increased to the predetermined temperature when depositing a film on a substrate. The process chamber temperature may be increased prior to chamber cleaning in operation 2204.

[0399] In operation 2204, a plasma effluent may be delivered to the process chamber. To this end, one or more source gases are supplied to a remote plasma source to generate a plasma effluent. As described herein, in some embodiments, the one or more source gases may include an oxygen-containing reactant, such as oxygen (O2), carbon dioxide (CO2), or nitrogen dioxide (NO2), a fluorine-containing reactant, such as nitrogen trifluoride (NF3), fluorine (F2), carbon tetrafluoride (CF4), or carbon hexafluoride (C2F6), a hydrogen-containing reactant, such as hydrogen (H2) or methane (CH4), an inert gas, such as argon (Ar), or a nitrogen-containing reactant, such as nitrogen (N2), ammonia (NH3), diazene (N2H2), or hydrazine (N2H4), or a mixture thereof. In some embodiments, the source gas may include an oxygen-containing reactant, a fluorine-containing reactant, and an inert gas. The source gas may be supplied to the remote plasma source as a gas mixture, or separate gases may be supplied to the remote plasma source. In some embodiments, the flow rate of the source gas to the remote plasma source ranges from about 1 to about 50 liters per minute (lpm), from about 1 to about 30 lpm, or from about 1 to about 20 lpm. In some embodiments, the process chamber temperature in operation 2204 can be configured to be the same as the temperature in operation 2202.

[0400] In some embodiments, the plasma is generated in a remote plasma source. The plasma may include ions, radicals, and charged neutrals of one or more source gases. The plasma may be generated using an inductively coupled plasma (ICP) reactor, a capacitively coupled plasma (CCP) reactor, a microwave plasma reactor, a DC plasma reactor, or a laser-produced plasma reactor. For example, the plasma may be generated using an ICP reactor. The plasma generated in the remote plasma source may be delivered to the process chamber through a showerhead as a plasma flow.

[0401] The plasma effluent generated from the remote plasma source may include hydrogen radicals, nitrogen radicals, oxygen radicals, fluorine radicals, amine radicals, argon radicals, or mixtures thereof. In some cases, the plasma effluent includes at least fluorine radicals. In some embodiments, the process chamber pressure during chamber cleaning by delivering the plasma effluent may range from about 0.6 Torr to about 30 Torr, or from about 1 Torr to about 30 Torr. The plasma effluent may be delivered inside the process chamber after the process chamber temperature reaches a predetermined temperature. In some embodiments, heating the process chamber and delivering the plasma effluent may occur substantially simultaneously.

[0402] In some embodiments, the remote plasma source may be positioned above the process chamber. The plasma flow generated above the process chamber may pass through the showerhead in a downward or substantially downward direction toward the pedestal. In other embodiments, the remote plasma source may be positioned elsewhere on the plasma processing device. For example, the remote plasma source may be a subunit that is removably bolted to the side of the plasma processing device. The remote plasma source may be constructed such that the plasma flow from the remote plasma source may flow horizontally or diagonally toward the showerhead, depending on the location of the remote plasma source relative to the showerhead. In one example, the plasma flow may be provided across the showerhead from a remote plasma source positioned on the side of the process chamber.

[0403] When the plasma flow containing fluorine radicals is delivered into the process chamber, the fluorine radicals in the plasma flow may contact deposition by-products on the surface regions of the internal components or the interior surfaces of the process chamber. Upon contact with the fluorine-containing species, the deposition by-products may dissociate into gaseous by-products. The gaseous by-products may be transported within the process chamber until they are removed from the process chamber via an outlet fluidly coupled to a pump.

[0404] In operation 2206, deposition by-products in the process chamber are etched away to prevent the delivery of gaseous contaminants to the showerhead surface. In some embodiments, the gaseous contaminants include metal fluorides. In some embodiments, the gaseous contaminants include aluminum fluoride. It should be appreciated that in some embodiments, the process chamber temperature in operation 2206 can be maintained substantially the same as the temperature in operations 2202, 2204. For example, the process chamber temperature of about 450° C. to about 650° C., about 500° C. to about 600° C., or about 530° C. to about 570° C. can be maintained substantially the same from the start of operation 2202 to the completion of operation 2206.

[0405] When introduced into the process chamber through a showerhead, the plasma stream may have a sufficient flow rate to contact deposition by-products on the interior surfaces of the process chamber, and the fluorine-containing species may react with the deposition by-products to produce gaseous by-products such as silicon tetrafluoride (SiF4).

[0406] The plasma flow may also react with aluminum in the aluminum-containing portion to form aluminum fluoride. For example, fluorine-containing species may react with a pedestal made of aluminum nitride to form aluminum fluoride on the pedestal surface. Depending on the process chamber temperature (or substrate temperature), condensed aluminum fluoride or gaseous aluminum fluoride may form. In some embodiments, the condensed aluminum fluoride may be converted to a gas phase above a certain temperature. For example, aluminum fluoride may thermally desorb at temperatures above about 450° C. The plasma flow may limit the diffusion of gaseous contaminants (e.g., aluminum fluoride) from the showerhead. The plasma flow may prevent contamination of the showerhead surface with gaseous aluminum fluoride, leaving the showerhead surface substantially free of contamination.

[0407] In some embodiments, the flow rate of the plasma flow can be proportional to the flow rate of one or more source gases supplied to the remote plasma source. For example, the flow rate of the plasma flow can be increased by increasing the flow rate of the source gas entering the remote plasma source. The velocity of the plasma flow can be configured to be greater than the velocity of the gaseous aluminum fluoride, which can be non-directional and random. When a high flow rate plasma flow containing fluorine-containing species is supplied from the showerhead toward the pedestal at a given temperature, the diffusion of the gaseous aluminum fluoride is limited to enter the plasma volume, and the showerhead is not substantially exposed to the gaseous aluminum fluoride.

[0408] In some embodiments, the flow rate of the one or more source gases may be at least 10 lpm, or at least 13 lpm, or at least 16 lpm. In some embodiments, the flow rate of the one or more source gases may be less than about 22 lpm, or less than about 25 lpm, or less than about 28 lpm. In some embodiments, the source gas may include nitrogen trifluoride at a flow rate of about 1 to about 5 lpm, or about 1.5 to about 4 lpm, or about 1.8 to about 4 lpm, oxygen at a flow rate of about 3 to about 10 lpm, or about 3.5 to about 8 lpm, or about 4 to about 7 lpm, argon at a flow rate of about 0 to about 16 lpm, or about 0.01 to about 10 lpm, or about 0.1 to about 7 lpm, or a mixture thereof. In some embodiments, the flow rate of the source gas may be 1 to about 50 lpm, or 1 to about 30 lpm, or 1 to about 20 lpm.

[0409] Because gaseous aluminum fluoride may be restricted from entering the plasma flow volume, the underside of the showerhead facing the pedestal is not substantially exposed to gaseous aluminum fluoride, and the showerhead surface may be maintained substantially contaminant-free after cleaning the chamber according to some embodiments for more than 20 minutes, or 25 minutes, or 30 minutes, or 40 minutes, or 60 minutes. In some embodiments, cleaning the chamber according to some embodiments may not require the additional steps of disassembling the chamber, cleaning, and assembling the chamber to remove the aluminum fluoride on the showerhead.

[0410] It should be understood that the above flow rate ranges for the source gases may vary depending on the design of the plasma processing apparatus to achieve a substantially contaminant-free showerhead surface. For example, the flow rates of the source gases may vary depending on the process chamber size, process chamber pressure, and / or process chamber temperature, etc.

[0411] In operation 2208, after preventing the showerhead from being contaminated by gaseous contaminants (e.g., aluminum fluoride), a substrate can be provided into the processing chamber from another chamber or another station for film deposition. The substrate can be supported on a pedestal for film deposition, and a silicon-based film as described herein can be deposited on the substrate. In some embodiments, the process chamber temperature in operation 2208 is set to be substantially the same as the temperature in operations 2202, 2204, and 2206. For example, the process chamber temperature can be about 450° C. to about 650° C., or about 500° C. to about 600° C., or about 530° C. to about 570° C. If film deposition is performed before operation 2202, the process chamber temperature in operations 2202, 2204, 2206, and 2208 can be substantially the same as the temperature during film deposition before operation 2202.

[0412] In operation 2210, a film may be deposited on a substrate in a process chamber. Films such as doped or undoped silicon carbide and other films as described herein may be deposited by ALD, PEALD, CVD, PECVD, or any suitable deposition process. The deposited film may be a silicon-based film including doped or undoped silicon carbide, for example, oxygen-doped silicon carbide (SiCO), nitrogen-doped silicon carbide (SiCN), and nitrogen- and oxygen-doped silicon carbide (SiOCN). The silicon-based film may also include silicon oxide (SiOx), silicon nitride (SixNy), or oxygen-doped silicon nitride (SiON). During the deposition process in operation 2210, a silicon-containing precursor may be flowed to the substrate. The silicon-containing precursor may react with a remote plasma provided from a remote plasma source, and Si-H and / or Si-Si bonds in the silicon-containing precursor may be broken and serve as reaction sites for forming bonds between the silicon-containing precursors in the deposited silicon-based film. The broken bonds can also serve as sites for cross-linking during thermal treatments performed during or after deposition. The bonds and cross-links at the reactive sites can collectively form a primary skeleton or matrix in the resulting silicon carbide film.

[0413] The temperature of the environment adjacent to the substrate may be a deposition temperature that promotes the deposition reaction. The deposition temperature may be limited by the application of the device including the silicon-based film. In some embodiments, the process chamber temperature in operation 2210 may be set to be substantially the same as the temperature in operations 2202, 2204, 2206, and 2208, and may be about 450°C to about 650°C, or about 500°C to about 600°C, or about 530°C to about 570°C. If film deposition is performed before operation 2202, the process chamber temperature in operations 2202, 2204, 2206, 2208, and 2210 may be substantially the same as the temperature during film deposition before operation 2202. The process chamber pressure may be any pressure suitable for generating reactive radicals in the process chamber. For example, the pressure may be about 0.6 Torr to about 30 Torr, or about 1 Torr to about 30 Torr, such as in embodiments performing an inductively coupled plasma.

[0414] One or more film depositions in operation 2210 may be performed prior to cleaning the interior of the process chamber with a plasma flow. For example, a film may be deposited on a substrate in the process chamber. The substrate may be exposed to a silicon-containing precursor, a radical species, a co-reactant, and / or a carrier gas until a film in a particular thickness range is obtained. In some embodiments, the process chamber temperature during operation 2210 may be set to be the same as the predetermined temperature in operations 2202, 2204, 2206, and 2208. Thus, from the start of heating the process chamber in operation 2202 to the completion of the film deposition in operation 2210, the process chamber temperature may not change, but instead be kept at the predetermined temperature.

[0415] After the film deposition in operation 2210, the substrate may be transferred from the process chamber to another process chamber or another station module for the next processing step. Another substrate may be transferred into the process chamber for further film deposition. After performing a predetermined number of depositions, the process chamber may be cleaned according to some embodiments described herein. In one example, the process chamber temperature may be maintained at a predetermined temperature after depositing one or more films in operation 2210. The process chamber cleaning process may begin by delivering a high flow rate plasma flow comprising fluorine into the process chamber (operation 2204). As described above for operation 2204, a high flow rate plasma flow comprising fluorine-containing species may be introduced from a remote plasma source into the process chamber through a showerhead to remove deposition by-products and prevent contamination of the showerhead with gaseous contaminants (e.g., aluminum fluoride). The process chamber temperature in operation 2204 may be maintained the same or substantially the same as the temperature operation 2210. As described herein, gaseous aluminum fluoride produced during chamber cleaning is confined from the showerhead by the high flow rate of the plasma stream, leaving the showerhead surface substantially free of fluoride contamination.

[0416] FIG. 23 is a scanning electron micrograph (SEM) image of a ceramic coupon positioned on the underside of a showerhead after chamber cleaning with a plasma flow according to some embodiments. The coupon was positioned at the center of the underside of the showerhead at a predetermined distance from the pedestal. The plasma flow was generated by a remote plasma source that was fluidly coupled with the process chamber through the showerhead and located upstream of the process chamber from an inductively coupled plasma generator, whereby the remote plasma source delivers the plasma flow to the process chamber. The flow rate for the fluorine-containing source gas to the remote plasma source was set at about 15 to about 22 lpm. The pedestal temperature was set at about 500° C. to about 600° C. The coupon was exposed to the plasma flow for about 10 hours before being removed to confirm the presence of aluminum fluoride. As shown in FIG. 23, the ceramic coupon shows only grain. Substantially no sign of aluminum fluoride flakes or particles was observed. This indicates that providing a high flow rate of plasma flow according to some embodiments is effective in substantially preventing redeposition of aluminum fluoride on the showerhead.

[0417] According to some embodiments, cleaning the surface area of ​​the internal components or walls of the process chamber by plasma flow has several advantages. At an appropriate temperature of about 450°C to about 650°C, or about 500°C to about 600°C, or about 530°C to about 570°C, a high flow rate plasma flow including fluorine-containing species generated from a remote plasma source can effectively limit the diffusion of gaseous aluminum fluoride from the showerhead, thereby obtaining a substantially contaminant-free showerhead. Also, the process chamber cleaning by plasma flow and the subsequent deposition can be performed at substantially the same temperature without cooling the process chamber for chamber cleaning. In addition, the process chamber cleaning and the subsequent film deposition can be performed using the same hardware without introducing new hardware components and without requiring disassembly of the hardware components. Thus, increased throughput and reduced manufacturing time are achieved.

[0418] In the foregoing description, numerous specific details are set forth to provide a thorough understanding of the presented embodiments. The disclosed embodiments may be practiced without some or all of these specific details. In other instances, well-known process operations have not been described in detail so as not to unnecessarily obscure the disclosed embodiments. It will be understood that while the disclosed embodiments are described in conjunction with specific embodiments, they are not intended to limit the disclosed embodiments.

[0419] Although the foregoing embodiments have been described in some detail for clarity of understanding, it will be apparent that certain changes and modifications may be practiced within the scope of the appended claims. It should be noted that there are many alternative ways of implementing the processes, systems, and apparatus of the present embodiments. Thus, the present embodiments should be considered as illustrative rather than restrictive, and the embodiments should not be limited to the details set forth herein.

Claims

1. 1. A method for forming a metal-containing layer on a semiconductor substrate, comprising: (a) co-flowing a metal-containing precursor and a reactant into a process chamber containing the semiconductor substrate; and (b) after (a), flowing the reactant into a process chamber containing the semiconductor substrate, the reactant not reacting with a vapor phase metal-containing precursor; To carry out at least one of the following: A method comprising:

2. 2. The method of claim 1 , (b) comprises reacting a surface-bound metal-containing precursor with said reactant in the absence of a plasma to form a metal-containing layer on said semiconductor substrate.

3. 3. The method of claim 2, 13. The method of claim 12, wherein the formed metal-containing layer is a substantially carbon-free molybdenum- or tungsten-containing layer having a carbon content of less than about 5 atomic %, the layer being selected from the group consisting of layers of molybdenum (Mo), tungsten (W), molybdenum nitride (MoN), tungsten nitride (WN), molybdenum oxynitride (MoON), tungsten oxynitride (WON), molybdenum boride (MoB), tungsten boride (WB), molybdenum silicide (MoSi), tungsten silicide (WSi), and combinations thereof.

4. 2. The method of claim 1 , The method of claim 1, wherein the metal-containing precursor is a halide-free, carbonyl-free compound comprising at least one ligand, the at least one ligand being bonded to a metal selected from the group consisting of molybdenum and tungsten.

5. 5. The method of claim 4, The method, wherein said halide-free, carbonyl-free compound does not contain metal-carbon and metal-oxygen double bonds.

6. 3. The method of claim 2, The method of claim 1, wherein the formed metal-containing layer has a carbon content of less than about 2 atomic percent.

7. 2. The method of claim 1 , The method of claim 1, wherein the formed metal-containing layer is selected from the group consisting of Mo, MoN, and MoON.

8. 1. A method for cleaning a process chamber, comprising: flowing a fluorine-containing species into the process chamber, the process chamber including a molybdenum-containing film formed on an interior surface of the process chamber; periodically or simultaneously flowing an oxygen-containing species into the process chamber together with the fluorine-containing species to clean the process chamber, wherein the molybdenum-containing film is removed from the interior surfaces of the process chamber. A method comprising:

9. 1. A method for cleaning a dielectric material from one or more components of a process chamber, comprising: (a) introducing into the process chamber (i) a remote plasma comprising a fluorine species and (ii) a thermal etchant that undergoes a ligand exchange reaction with fluorine-containing reaction products of the dielectric material to generate volatile reaction products; (b) removing the volatile reaction products from the process chamber; A method comprising:

10. 1. A method for cleaning a process chamber, comprising: heating the process chamber to a predetermined temperature; delivering a plasma flow from a remote plasma source through a showerhead into the process chamber to clean the process chamber, the remote plasma source being fluidly coupled to the process chamber through the showerhead and positioned upstream of the process chamber, the plasma flow limiting diffusion of gaseous contaminants from the showerhead; method.

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