Pre-treatment for molybdenum gap-fill

Abstract

Methods for deposition of molybdenum (Mo) in features include treating a feature surface prior to Mo deposition. According to various embodiments, the methods involve an oxidizing plasma preclean followed by a non-plasma metal halide treatment. Molybdenum deposition is then performed.

Description

Attorney Docket No. LAM1P074WO-12060-1WOPRE-TREATMENT FOR MOLYBDENUM GAP-FILLINCORPORATION BY REFERENCE

[0000] A PCT Request Form is filed concurrently with this specification as part of the present application. Each application that the present application claims benefit of or priority to as identified in the concurrently filed PCT Request Form is incorporated by reference herein in their entireties and for all purposes.BACKGROUND

[0001] Deposition of conductive materials is an integral part of many semiconductor fabrication processes. These materials may be used for horizontal interconnects, vias between adjacent metal layers, contacts between metal layers and devices, and as lines in memory devices. In an example of deposition, a tungsten (W) layer may be deposited on a titanium nitride (TiN) barrier layer to form a TiN / W bilayer by chemical vapor deposition (CVD) process using tungsten hexafluoride (WFe). However, as devices shrink and more complex patterning schemes are utilized in the industry, the deposition of thin tungsten becomes a challenge. The continued decrease in feature size and film thickness brings various challenges to TiN / W film stacks. These include high resistivity for thinner films and deterioration of TiN barrier properties.

[0002] The background description provided herein is for the purpose of generally presenting the context of disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.SUMMARY

[0003] One aspect of the disclosure relates to a method for pre-treating a substrate. The method includes a) providing a substrate including a feature to a chamber, wherein the feature is formed within a layer on the substrate and is surrounded by a field region and includes a bottom surface and sidewall surfaces that extend from the field region to the bottom surface, wherein the sidewall surfaces are dielectric surfaces and the bottom surface is a conductive metal surface or an oxide thereof; b) exposing the substrate to an oxidizing plasma; and c) after (b), exposing the substrate to one or both of a reducing plasma and a non-plasma metal halide treatment.Attorney Docket No. LAM1P074WO-12060-1WO

[0004] In some embodiments, the feature in (a) includes carbon-containing residue and (b) removes the carbon-containing residue.

[0005] In some embodiments, wherein the oxidizing plasma is generated from a process gas including an oxygen source and hydrogen (H2). ISSE, a volumetric ratio of the H2 to the oxygen source is at least 2:1.

[0006] In some embodiments, the method further includes, after (c), (d) filling the feature with molybdenum.

[0007] In some embodiments, (b)-(d) are performed in the chamber.

[0008] In some embodiments, (c) includes exposing the substrate to a reducing plasma followed by a non-plasma metal halide treatment.

[0009] In some embodiments, (c) includes exposing the substrate to reducing plasma only.In some embodiments, (c) includes exposing the substrate to a non-plasma metal halide treatment only.

[0010] In some embodiments, (c) includes the non-plasma metal halide treatment and the non- plasma metal halide treatment removes terminal groups from the bottom surface to leave a pure conductive metal surface.

[0011] In some embodiments, no metal is deposited during the non-plasma metal halide treatment.

[0012] In some embodiments, the oxidizing plasma is formed in a plasma generator remote to the chamber.

[0013] In some embodiments, the oxidizing plasma is formed in the chamber.

[0014] Another aspect of the disclosure relates to an apparatus including: a multi-station chamber, wherein each station includes a substrate support configured to support a substrate, a showerhead configured to inlet gases to a volume above substrate support, and at least one of the stations further includes a plasma generator configured to generate a plasma between the substrate support and showerhead; and a controller having instructions for:Attorney Docket No. LAM1P074WO-12060-1WO co-flowing hydrogen (H2) and an oxygen-containing gas to a first station housing the substrate; while the substrate is in the first station, generating an oxidizing plasma in the first stationtransferring the substrate to a second station; and while the substrate is in the second station, inletting a metal halide to the second station.

[0015] In some embodiments, the controller further includes instructions for generating a reducing plasma in a station housing the substrate. In some embodiments, the instructions for generating the reducing plasma include instructions for generating the reducing plasma after generating the oxidizing plasma.

[0016] These and other aspects of the disclosure are described below with reference to the drawings.BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1A shows an example of a feature to be pre-treated and filled with molybdenum according to various embodiments.

[0018] Figure IB shows the feature of Figure 1A after fill with molybdenum.

[0019] Figures 2A-2C show examples of a feature during a fill process with carbon-containing residue present in the feature.

[0020] Figures 3A and 3B are flow diagrams showing operations in methods of pre-treating a substrate surface according to various embodiments.

[0021] Figures 4A-4D show examples of a feature during a fill process according to various embodiments.

[0022] Figure 5 is a flow diagram showing operations in a method of interconnect metallization.

[0023] Figure 6A shows cross-sectional representations of a feature during various stages of the process of Figure 5.

[0024] Figure 6B shows examples of sub-processes that may be performed for single chamber interconnect metallization.Attorney Docket No. LAM1P074WO-12060-1WO

[0025] Figure 6C is a flow diagram showing operations in a method of depositing molybdenum.

[0026] Figure 6D shows etch thickness per etch cycle of various materials.

[0027] Figure 7 depicts a schematic illustration of an embodiment of an atomic layer deposition (ALD) process station.

[0028] Figure 8A and Figure 8B show examples of semiconductor processing tools.DETAILED DESCRIPTION

[0029] In the following descriptions, numerous specific details are set forth to provide a thorough understanding of the presented embodiments. The disclosed embodiments may be practiced without some or all of these specific details. In other instances, well-known process operations have not been described in detail to not unnecessarily obscure the disclosed embodiments. While the disclosed embodiments will be described in conjunction with the specific embodiments, it will be understood that it is not intended to limit the disclosed embodiments.

[0030] Provided herein are methods for deposition of molybdenum (Mo) in features. The methods include treating a feature surface prior to Mo deposition. According to various embodiments, the methods involve an oxidizing plasma preclean followed by a non-plasma metal halide treatment. Molybdenum deposition is then performed.

[0031] Figure 1A shows a schematic diagram of a feature 102 to be filled with molybdenum (Mo). The feature 102 may also be referred to as a gap, with filling the feature referred to as gapfill. In the example of Figure 1A, the feature 102 is formed in a dielectric layer 106 to expose a metal layer 104. In some embodiments, a layer of metal oxide 108 is formed on the metal layer 104. The structure shown in Figure 1A may be on a semiconductor substrate (e.g., a silicon (Si) or silicon germanium (SiGe) wafer) with any number of intervening layers between the substrate surface and the metal layer 104. The methods may also be applied to form metallization stack structures on other substrates, such as glass, plastic, and the like.

[0032] Examples of dielectric layers include doped and undoped silicon oxide, silicon nitride, and aluminum oxide layers, with specific examples including doped or undoped layers of silicon nitride (SiN), silicon dioxide (SiOz), and aluminum oxide (AI2O3). In some embodiments, the dielectric layers are low-k dielectric layers including carbon doped oxides. Oxide include alkoxides such asAttorney Docket No. LAM1P074WO-12060-1WO poly(2-ethyl-2-oxazoline) (PEOX) and tetraethyl orthosilicate (TEOS), fluorosilicate glass (FSG), flowable oxides, spin-on-glasses, as well as carbon doped oxides, etc. In some embodiments, the oxide surface is a silicon-based oxide with examples given above.

[0033] In some embodiments, the metal layer 104 is a tungsten (W) layer. Other examples include metals such as cobalt (Co), ruthenium (Ru), copper (Cu), nickel (Ni), iridium (Ir), rhodium (Rh), tantalum (Ta), and titanium (Ti). Still further, in some embodiments, the bottom of the feature is a conductive metal compound film. Examples include titanium aluminum carbide (TiAlxCy), titanium silicide (TiSiz), titanium nitride (TiN) and other conductive nitrides such as zirconium nitride (ZrN), hafnium nitride (HfN), vanadium nitride (VN), niobium nitride (NbN), tantalum nitride (TaN), as well as molybdenum nitride (MoN), tungsten nitride (WN), and tungsten carbon nitride (WCxNy). As described further below, conductive metal and metal compound surfaces may exhibit molybdenum deposition selectivity with respect to dielectric oxides.

[0034] Figure IB shows the structure after deposition of molybdenum 110 to fill the feature. The layer of metal oxide 108 has been removed. The result is low resistance contact between the molybdenum 110 and the metal layer 104. Metal oxide can be removed through exposure to a metal halide (e.g., molybdenum pentachloride (M0CI5)) or a hydrogen (H2) plasma. However, in some situations, such treatments can result in defects. Imaging feature after feature fill shows a dark or porous area in some features. These areas are evidence of defects that can lead to early device failure or reduced performance.

[0035] In some embodiments, the source of these defects is residue from prior processing. Examples of such residues include carbon and / or carbon fluoride (C / CFX) etch residues. If present during a deposition, these residues can result in porous or otherwise poor quality Mo deposition. These residues tend to be present in features especially when dense and isolated features are present on the same wafer. Preclean treatments such as metal halide exposure and / or hydrogen (H2) plasma exposure that are effective to remove metal oxide can stabilize the C / CFXresidues, leading to poor fill in some features. An example of such a process is shown in Figures 2A-2C.

[0036] Figure 2A shows an incoming feature 202 to be filled with molybdenum. As in Figure 1A, it is defined by a layer of metal 204 at the feature bottom and sidewalls of dielectric material 206. A layer of metal oxide 208 is present on the metal layer 204. Carbon-containing etch residue 214 is also present in the feature. Figure 2B shows the feature after treatment to remove the metalAttorney Docket No. LAM1P074WO-12060-1WO oxide. At least some of the carbon-containing residue 214 remains and in some situations may be further stabilized. Pure H2-based precleans, for example, can stabilize the residue through redeposition in the H2 plasma. An example reaction is H» + CH4 - H2 + C(soiid), with CH4 formed from previous reaction of the C-containing residue with the plasma. In another example, a metal halide treatment can stabilize carbon. Figure 2C shows an example of a dark spot 218 that appears in images of some features after fill with molybdenum 210.

[0037] Figures 3A and 3B show examples of methods that may be used for pre-treatment prior to feature fill. First, in Figure 3A, a substrate including a feature is provided at an operation 301. The substrate is generally provided to a semiconductor processing tool as described further below. In some embodiments, the substrate is provided to a semiconductor processing tool for pre-treatment and subsequent deposition under common vacuum. This allows the substrate to be processed without air break and further oxidation.

[0038] At 303, the substrate is exposed to an oxidizing plasma. As used herein, the term "oxidizing plasma" refers to any plasma that contains oxygen species (atoms, ions, or radicals). It may be generated from any appropriate oxygen-containing gas including oxygen (O2), nitrous oxide (N2O), carbon dioxide (CO2), and water (H2O). The oxidizing plasma removes C-containing residues by combustion. According to various embodiments, it may be generated from a process that includes one or more of O2, H2, N2O, N2, Ar, He, other noble gases, and other gases.

[0039] An oxidizing plasma can oxidize the metal surfaces on the substrate, including the metal layers at the feature bottoms. An oxidizing plasma can also damage a low-k dielectric material by reacting with carbon-containing groups within the layer. In some embodiments, the oxidizing plasma is generated from a process gas having a composition that reduces or prevents reaction with the dielectric and metal layers of the features or elsewhere on the substrate. For example, an oxidizing plasma may be generated from a process gas including an oxygen source and H2. The ratio of H2 to the oxygen source is controlled to prevent damage to the low-k dielectrics and further oxidation of the metal, while allowing combustion and removal of the C-containing residue. The mix of species in the oxidizing plasma may be controlled by appropriately controlling the process gas composition. For example, plasmas generated from O2 typically have a range of different oxidizing species. With N2O, the reactive species are mostly limited to oxygen radicals.

[0040] The oxidation pathway is more thermodynamically favorable than reaction with hydrogen to remove carbon-containing residue. Thus, unlike with a reducing plasma, re-Attorney Docket No. LAM1P074WO-12060-1WO deposition of carbon is not a risk of an oxidizing plasma since the carbon is fully oxidized to volatileCO2.

[0041] In some embodiments, the oxidizing plasma is formed in a process gas including H2 and an oxygen source. In some embodiments, oxidation of the metal and / or damage to low-k dielectric is suppressed by selecting a sufficiently high ratio of H2 to the oxygen source. For example, in some embodiments the ratio of H2to the oxygen source is at least about 4:1 by volume. In one implementation the oxygen source is O2 and the ratio of H2 to O2 is at least about 9:1. For example, the process gas may consist essentially of H2, O2 and an inert gas, where the concentration of H2 is about 2-10% by volume and the concentration of O2 is less than about 1% by volume. In another example, the process gas consists essentially of H2 (at a concentration of greater than 95% by volume) and O2 (at a concentration of less than about 5% by volume). In some embodiments, the plasma is formed directly in the process chamber or process chamber compartment that houses the substrate. In other embodiments, the plasma is formed in the process gas remotely in a compartment that is different from the compartment that is housing the substrate and is then delivered to the compartment housing the substrate. In some embodiments the plasma is formed using a frequency in a range of between about 2.45 - 13.56 MHz, and using a power in a range of between about 2 - 6 kW. In one example, the plasma is formed in a process gas containing H2, 02, and, optionally, an inert gas using a frequency of 13.56 MHz and a power of 3 kW. In some embodiments the pressure used in this reaction step is less than about 2 Torr, such as 1.5 Torr or less.

[0042] In some embodiments, O2 and H2 are co-flowed into the chamber housing the substrate. Chamber pressure may be 20 Torr or less, with flows of O2 up to 5 standard liters per minute (SLM) and H2 flows up to 100 SLM.

[0043] In some embodiments, the chamber in which the substrate is exposed to the oxidizing plasma includes an undercoat that prevents damage to the chamber walls and components. In some embodiments, the chamber undercoat is an SiCh undercoat.

[0044] Operation 303 is performed a time sufficient to remove C-containing residue. At this stage, some -O and -H terminating groups may be present on the metal layer in the feature. The substrate is exposed to a metal halide treatment in an operation 305 to prepare the substrate for molybdenum fill. Operation 303 is a non-plasma treatment. In some embodiments, the metal halide is a molybdenum halide or another metal halide, such as a tungsten halide. In someAttorney Docket No. LAM1P074WO-12060-1WO embodiments, a molybdenum halide is a molybdenum chloride (MoClx) compound. Molybdenum chloride compounds are given by the formula MoClx, where x is 2, 3, 4, 5, or 6, and include molybdenum dichloride (MoCh), molybdenum trichloride (M0CI3), molybdenum tetrachloride (M0CI4), molybdenum pentachloride (M0CI5) and its dimer M02CI10, and molybdenum hexachloride (MoCk). In some embodiments, M0CI5 or MoCk are used. Other molybdenum halide compounds may be used. Molybdenum halide precursors are given by the formula MoXz, where X is a halogen (fluorine (F), chlorine (Cl), bromine (Br), or iodine (I)) and z is 2, 3, 4, 5, or 6. Examples of MoXz precursors include molybdenum fluoride (MoFe). Tungsten halides including tungsten hexafluoride (WFe), tungsten hexachloride (WCk), and tungsten pentachloride (WC ) may be used. In some embodiments, a non-fluorine-containing metal halide is used to prevent fluorine etch or incorporation. However, tungsten hexafluoride (WFe) or molybdenum hexafluoride (MoFe) may be used in some embodiments. These pre-treatment agents are gases at standard pressure and temperature, allowing delivery at room temperature through a mass flow controller. MoFe is a strong etchant and may be provided at very low concentrations if used. For example, a concentration of MoFe dose may be 0.01% (molar) or less, 0.008% or less, 0.005% or less, or 0.004% or less of the total gas flowed into the chamber. The balance may be wholly or predominately argon or other inert gas. Some amount of a reducing agent may be present to suppress etching, e.g., between 0.5% (molar) and 10% or between 1% and 9% H2 or other reducing agent. In addition to the metal halides described above, certain metal oxyhalides may also be used, including molybdenum oxytetrachloride (MoOCU).

[0045] In the example of Figure 3A, after operation 305, a deposition process may be performed to fill the feature with molybdenum. Further detail and examples of operations 303 and 305 as well as deposition processes are given below.

[0046] Figure 3B shows another example of a method that may be used for pre-treatment prior to feature fill. In the example of Figure 3B, operations 301 and 303 may be performed as described above with respect to Figure 3A. After performing the oxidizing plasma exposure operation 303 and prior to performing the metal halide exposure operation 305, the substrate is exposed to a reducing plasma in operation 304. In the context of this disclosure, reducing plasma refers to a plasma generated from a process gas or gasses including H2 alone or with one or more noble gases such as argon (Ar) and helium (He). The process gas used to generate the reducing plasma does not include oxygen species, nitrogen species, or any other species that can oxidize, nitridize, or otherwise react with the metallic surface to form a metal oxide, metal nitride, metalAttorney Docket No. LAM1P074WO-12060-1WO carbide, metal silicide, etc. Other species may be present in no more than trace amounts. The reducing plasma removes any residual oxygen from the metallic surface at the bottom of the structure. In some embodiments, operation 305 may be omitted from the process flow of Figure 3B with the reducing plasma sufficient to remove any remaining oxide. In other embodiments, operation 305 may be performed to remove any -O and / or -H terminal groups.

[0047] An example of process according to Figure 3A or 3B is shown in Figures 4A-4D. Figure 4A shows an incoming feature 202 to be filled with molybdenum. As described above, it is defined by a layer of metal 204 at the feature bottom and sidewalls of dielectric material 206. A layer of metal oxide 208 is present on the metal layer 204. Carbon-containing etch residue 214 is also present in the feature. Figure 4B shows the feature after exposure to an oxidizing plasma. All of the carbon-containing residue 214 is removed as CO2 with no re-deposition. The layer of metal oxide 208 is present at this stage. Figure 4C shows the feature 202 after exposure to a reducing plasma and / or a metal halide gas. The oxide is completely removed, leaving a cleaned metallic surface for deposition. Figure 4D then shows the feature after fill with molybdenum 210. Unlike the feature shown Figure 2C, there is no dark spot indicating a defect.

[0048] According to various embodiments, an oxidizing plasma operation, such as operation 303 in FiguresSA and 3B, may be performed in a single operation or with multiple cycles. If performed with multiple cycles, there may be an optional purge between sequential oxidizing plasma exposures. Parameters of the oxidizing plasma may be same or different from cycle-to-cycle. Any of process composition, plasma power, and duration may be modified, for example, to increase or decrease the oxidizing strength as operation proceeds.

[0049] Similarly, a reducing plasma operation, such as operation 304 in Figure 3B may be performed in a single operation or with multiple cycles. If performed with multiple cycles, there may be an optional purge between sequential reducing plasma exposures. Parameters of the reducing plasma may be same or different from cycle-to-cycle. Any of process composition, plasma power, and duration may be modified, for example.

[0050] A metal halide exposure operation, such as operation 305 in Figures 3A and 3B may also be performed in a single operation or with multiple cycles. If performed with multiple cycles, there may be an optional purge between exposures. The metal halide may be flowed alone or with an inert gas (such as Ar). In many embodiments, operation 305 involves exposure to the molybdenum halide compound without a co-reactant gas. In such embodiments, theAttorney Docket No. LAM1P074WO-12060-1WO molybdenum halide may be pulsed or delivered in a continuous dose. For examples, M0CI5 may be pulsed with argon (Ar) other inert gas for a certain number of cycles. Alternatively, a continuous dose of M0CI5 can be delivered followed by an Ar purge. Further examples of metal halide treatments are provided below.

[0051] In some embodiments, operation 305 involves exposure to the molybdenum halide compound with a co-reactant gas to deposit Mo. The co-reactant is generally H2, though other reducing agents as described below may be used. In one example sequence, M0CI5 pulses are alternated with H2 pulses with intervening purge gas pulses. In another example, M0CI5 pulses are alternated with H2 pulses with no intervening purge gas pulses. In another example sequence, M0CI5 pulses are alternated with H2 pulses with a purge gas pulse directly after only one of the reactant gases in each cycle. In another example sequence, M0CI5 is flowed with H2. In the further example sequence, the co-flowed reactants are pulsed with an alternating Ar pulse. In another example sequence, H2 gas may be flowed into the chamber and is continuously flowing into the chamber while M0CI5 is intermittently flowing into the chamber. In any of these examples, another molybdenum halide and / or another inert gas may be used instead of M0CI5 and Ar, respectively. In some embodiments, sequences with a co-reactant may be employed when metals besides Mo are at the feature bottom. In such embodiments, a Mo surface layer may be formed facilitating subsequent Mo growth. For example, if a W, Co, or Ru layer is at the feature bottom, operation 305 may be used to form a thin Mo surface layer.Single Chamber Metallization

[0052] Figure 5 is a process flow diagram illustrating example operations in a method 500 for interconnect metallization. The method 500 begins with an operation 501 in which a feature having dielectric sidewalls and a metal-containing contact is provided. The metal-containing contact may be at the bottom of the feature with the dielectric sidewalls extending from the feature opening to the metal-containing contact. The feature may be provided to a processing chamber. In some embodiments, one or more processing operations may occur in the processing chamber to form the feature having dielectric sidewalls and a metal-containing containing contact.

[0053] Examples of dielectric sidewalls include silicon-containing layers such as oxides and nitrides. Examples of metal-containing contacts include metals and metal compound films. The metal-containing contact may be generally conductive, having a conductivity of at least 104Q-1- cm1at room temperature. Examples include TiN, TiAIC, W, Co, Mo, Ru, Cu, Ni, Rh, Ir, Ta, Ti, TiSix,Attorney Docket No. LAM1P074WO-12060-1WORuSix, N iPtSix, TiSiN, MoSix, CoSix. and TaN.

[0054] In some embodiments, a surface oxide is present on the metal-containing contact. Still further, in some embodiments, a layer containing other impurities is present on the metalcontaining contact. In some embodiments, an etch operation to remove a liner layer from at least the sidewalls of the feature is performed prior to operation 501. For example, a feature may include a TiN liner layer conformally coating the bottom and sidewalls. An etch may be performed to remove the TiN layer from the sidewalls, exposing dielectric material. The sidewall surfaces are then silicon oxide or other dielectric material.

[0055] In an operation 503, a pre-treatment is performed. The pre-treatment may be performed as described above with references to Figures 3A and 3B. In addition to or instead of any of the operations described above, operation 503 can involve an atomic layer clean with a chlorine-based plasma, a hydrogen fluoride (HF) vapor clean, an ammonium fluoride (NH4F) clean, or a treatment using other reducing agents. These operations may be used to reduce oxide of a feature surface. Still further, operation 503 may involve a metal halide treatment as described below. If the contact does not have carbon contamination, for example, a metal halide treatment may be used without prior exposure to oxidizing or reducing plasmas.

[0056] The process continues at operation 505 with selective deposition of a Mo pre-fill layer on the metal-containing contact. The selective deposition deposits a layer on the metalcontaining without significant deposition on the dielectric sidewalls.

[0057] In some embodiments, this operation involves reaction using a molybdenum halide or a molybdenum oxyhalide precursor. In some embodiments, MoCI5is used as it has good selectivity as described below.

[0058] Process conditions such as the precursor gas, the reducing agent, substrate temperature, process pressure, and exposure time may affect the selectivity of the Mo film being deposited. Different precursor gases may have different process windows in which Mo film may be selectively deposited. For example, MoCIs is selective while MOO2CI2 is not, i.e., under the same temperature and pressure conditions, the precursor gas of M0CI5 may deposit Mo only on a conductive surface and not on a dielectric surface while a precursor gas of MOO2CI2 will deposit Mo on both conductive and dielectric surfaces. Generally speaking, MoCIsgas has a large process window, i.e., large temperature and pressure range, where the precursor gas retains its selectivity. For example, M0CI5 may be selectively deposited on a metal material with respect to a dielectric material where the process temperature is 300°C to 800°C. In some embodiments, the substrate temperature is 350°C to 550°C. Generally speaking, higher process temperaturesAttorney Docket No. LAM1P074WO-12060-1WO and higher process pressures reduce the selectivity of the deposited film. For example, at higher temperatures, a precursor gas such as M0CI5 may lose its selectivity and deposit Mo film on both a metal surface and dielectric surface within a feature.

[0059] In some embodiments, operation 505 can be a thermal or plasma-based process. In some embodiments, operations 505 is a plasma-enhanced ALD (PEALD) or plasma enhanced CVD (PECVD) process using a molybdenum halide precursor. In some embodiments, the molybdenum halide precursor is M0CI5. Hydrogen (H2) or other reducing agent may be used for the PEALD or PECVD deposition.

[0060] In some embodiments, operation 505 can be a thermal process. It can be easier to achieve selectivity with a thermal process. In some such embodiments, operation 505 can involve a pulsed chemical vapor deposition (pulsed CVD) process. Pulsed CVD processes for selective deposition of a molybdenum are described further below.

[0061] Figure 6A shows cross-sectional representations of a feature during various stages of the process of Figure 5. The feature including a conductive bottom material 602 and dielectric sidewalls 604 is provided to a processing tool, where it undergoes a pre-treatment operation as described with reference to operation 305 of Figure 3A or 3B and / or operation 503 of Figure 5. After pre-treatment, the surface of the conductive bottom material is free of oxide and other residues. A selective deposition is then performed to deposit Mo 606 at the bottom of the feature. The selective deposition forms Mo on the conductive bottom material 602 without significant deposition on the dielectric sidewalls 604. This depicts an example of feature after operation 505 of Figure 5 with a layer of Mo is in the feature without deposition on the sidewalls above the layer.

[0062] Returning to Figure 5, a conformal Mo liner is deposited in an operation 507. The conformal Mo liner is deposited by a non-selective method that deposits on both the Mo pre-fill layer and the dielectric sidewalls. In some embodiments, MOO2CI2 may be used to deposit a conformal layer. The deposition may be a PEALD deposition using MOO2CI2. Above about 400°C, thermal ALD may be used to deposit a conformal layer using MOO2CI2. In some embodiments, M0CI5 may be used with a PEALD to deposit the conformal layer. This is shown in Figure 6A, with conformal Mo liner 608 deposited in the feature.

[0063] In some embodiments, operation 507 is not performed, with selective deposition continuing to fill the feature.

[0064] Returning to Figure 5, the process may continue with fill of the feature with Mo in an operation 509. The same or different Mo precursor may be used for operations 507 and 509.Attorney Docket No. LAM1P074WO-12060-1WO Operation 509 may include one or more deposition, inhibition, and etch operations as described further below. The sequence of these operations as well as the precursor used can depend on the feature profile. For example, if the feature is re-entrant, one or more etch and / or inhibition operations may be used to tailor the fill. For less challenging structures, such as V-shaped structures, PEALD using MOO2CI2 may be used, for example. These structures may also be filled using a pulsed CVD process in some embodiments. Further description of possible fill techniques of re-entrant features is described below. Figure 6A shows the structure after the fill, with bulk Mo film 610 in the feature.

[0065] Figure 6B shows examples of sub-processes that may be performed for interconnect metallization. In the example of Figure 6B, all of the operations described with reference to Figures 2A-6A are performed in a single chamber, which may be a multi-station or single station chamber. Such a chamber may be equipped for delivery of two solid precursors (e.g., M0CI5 and M0O2CI2). The example of Figure 6B refers to various inhibition and deposition-etch-deposition (DED) operations. These are described more fully below. In other embodiments, any one or more of the operations may occur in different chambers. These may be connected by vacuum in some embodiments.

[0066] Figure 6B describes single chamber interconnect metallization processes, including pretreatment, selective prefill, conformal liner, and final fill operations. Interconnect metallization may include all of pre-treatment, selective prefill, conformal liner, and final fill operations or a subset of these. For example, a single chamber metallization process may include pre-treatment followed by selective fill. See, e.g., Figure 6B, which shows a molybdenum halide (e.g., M0CI5) used for selective fill and final fill.

[0067] In another example, single chamber metallization process may include pre-treatment, selective prefill, followed by a deposition that results in complete fill of the feature. See, e.g., Figure 6B, which shows PECVD using M0O2CI2 for both the conformal liner and the final fill. A PECVD operation performed after pre-treatment and / or selective fill may be used to fill a feature without forming a conformal liner as part of a separate fill operation. This also may be characterized as deposition of a conformal liner continuing until the feature is filled. Examples of other single chamber fill processes include:Pre-treatment / conformal liner / final fillPre-treatment / selective prefill / final fillPre-treatment / selective fill (selective deposition is continued until feature fill is complete)Attorney Docket No. LAM1P074WO-12060-1WO

[0068] Any one or more of the sub-processes described may be used for each of pre-treatment, selective prefill, conformal liner, and final fill. Further, in some embodiments, an etch of a top portion of a molybdenum layer may be performed to reduce roughness and / or improve feature- to-feature uniformity. Examples of etches can include oxidation to form a molybdenum oxychloride or molybdenum oxide species followed by a treatment to remove the oxide and, if present, halogen species. Examples of such processes are described in U.S. Provisional Patent Nos. 63 / 678,724 and 63 / 709,90, incorporated by reference herein.

[0069] Pre-treatment is described above with reference to Figures 2A-4D. For interconnect metallization, the incoming bottom surface may be a conductive surface. Examples include elemental metal films such as tungsten, molybdenum, copper, cobalt, titanium, ruthenium, or metal-containing conductive compounds films such as titanium nitride and tungsten nitride. Sidewall surfaces are dielectric and include silicon oxides, silicon nitrides, silicon carbides, silicon oxycarbides, silicon oxynitrides, aluminum oxides, and the like. The pre-treatment can be used to remove surface oxides of the conductive surface and / ortreat dielectric sidewalls as discussed above.

[0070] Selective prefill, if performed, results in preferential deposition on the conductive surface relative to the dielectric surfaces. In some embodiments, it is performed to reduce the aspect ratio of the feature for subsequent fill. Processes that may be used include thermal deposition using a molybdenum halide, e.g., M0CI5 or MoFe. The thermal deposition may be an atomic layer deposition (ALD), a pulsed chemical vapor deposition process (pulsed CVD), or a continuous flow CVD process. ALD is a surface-mediated deposition technique in which doses of the Mo halide precursor and hydrogen (H2) are sequentially introduced into a deposition chamber, optionally with an argon or other inert gas purge between sequential reactant doses. One or more cycles of sequential doses of the molybdenum precursor and H2 are used to deposit Mo selectively. In continuous flow thermal CVD, the Mo halide and H2 are flowed concurrently to the chamber for a gas phase reaction. Pulsed CVD process sequences can involve continuous flow of one or more process gases and pulsed flow of one or more other process gases.

[0071] Selective deposition on conductive surfaces with respect to dielectric surfaces is an inherent feature using molybdenum halides and hydrogen (H2) for thermal ALD, thermal CVD, and thermal pulsed CVD at appropriate conditions. As described further below, M0CI5 and MoFe have a large process window, i.e., large temperature and pressure range, where the precursor gas retains its selectivity. For example, M0CI5 may be used to selectively deposit molybdenum on a metal or metallic conductive material with respect to a dielectric material where the processAttorney Docket No. LAM1P074WO-12060-1WO temperature is 200°C to 800°C, e.g., 250°C to 550°C, or 300°C to 500°C. Generally speaking, higher process temperatures and higher process pressures reduce the selectivity of the deposition. However, selectivity is significantly controlled by precursor identity with molybdenum halides resulting in much greater selectivity than molybdenum oxyhalides. Selectivity can also decrease with the use of stronger reducing agents than hydrogen. These include silane and diborane, for example. In some embodiments, plasma deposition may be used for selective prefill. In such embodiments, the plasma may be a remote plasma, with hydrogen radicals that are generated in a plasma generator remote to the process chamber fed to the reactor. Description of thermal ALD, thermal CVD, and thermal pulsed CVD herein may be modified with hydrogen radicals flowed to the chamber rather than hydrogen gas for selective deposition.

[0072] As noted above, selective deposition refers to deposition that preferentially occurs on one surface type over another. According to various embodiments, a feature may be provided to the chamber with two material types (e.g., a conductive metal bottom and dielectric sidewalls). In other embodiments, a feature may be provided to the chamber having a single material type that is treated to allow selective deposition. As an example, a feature may be provided with a TiN liner conformally lining the bottom and sidewalls of the feature. It may be exposed to a high temperature molybdenum halide that preferentially etches the TiN layer at top of the surface to form a TiN cup at the feature bottom, exposing dielectric sidewalls at the top of the surface. Molybdenum may then be selectively deposited on the TiN cup. The molybdenum halide exposure may be performed as part of the pre-treatment process described above. In another example, a feature having uniform surface materials may be treated by inhibiting deposition on a portion of the feature. For example, an inhibition treatment may be performed to inhibit deposition at the feature opening.

[0073] Deposition of the conformal liner is typically done by an ALD process rather than CVD to facilitate conformally depositing the liner on the contours of the feature. PEALD or thermal ALD may be used. If the feature has multiple material types (e.g., as in Figure 6A), PEALD with a direct plasma may be used with a molybdenum halide as it will result in conformal, non-selective deposition rather than selective deposition on the conductive surfaces. Example PEALD processes using M0CI5 may use substrate temperatures of 300°C or more. For molybdenum oxyhalides, either thermal or plasma ALD may be used. For thermal ALD, the temperature is high enough for deposition to occur, e.g., with M0O2CI2 and H2, deposition at 450°C or above may be used. For PEALD with MOO2CI2, a wide range of temperatures may be used. For example, aAttorney Docket No. LAM1P074WO-12060-1WO substrate temperature from 100°C to 600°C may be used.

[0074] If the feature itself is not selective - i.e., it has a uniform material throughout such as previously formed liner film - and that liner film is to be incorporated into the device, the conformal liner may be formed by any ALD process, thermal or plasma, using any molybdenum halide or oxyhalide precursor capable of deposition.

[0075] Examples of final fill subprocesses are also shown in Figure 6B. As indicated above, filling re-entrant structures is more challenging and may employ one or more inhibition or etch processes to achieve fill. In one example depicted in Figure 6B for a re-entrant structure, an fill process with a molybdenum oxyhalide or molybdenum halide can use a deposition-etch- deposition (DED) or deposition-inhibition-deposition (DID) process.

[0076] Figure 6B also shows an inhibition subprocess for molybdenum oxyhalide and molybdenum halide deposition processes. Inhibition refers to inhibiting molybdenum nucleation. As an example, halogenating a dielectric material or conductive material will inhibit subsequent nucleation. Examples of halogen-containing inhibitors include NF3, BCI3, M0CI5, and CI2.

[0077] For a DED process, Figure 6B shows examples of two alternative subprocesses - one a discrete intermittent DED and a simultaneous DED. A discrete intermittent DED process may involve a deposition of a first molybdenum film, followed by a partial etch of that film, followed by a second deposition of a molybdenum film. For an ALD process, am etch operation may be performed between any number of deposition cycles to tailor the feature profile. One or more DED processes may be performed during the fill. For a CVD process, the deposition may be stopped and the etched performed at the appropriate time to tailor the feature profile. A simultaneous DED process can involve adding an etchant to the reducing agent to preferentially etch a portion of the film while depositing. As an example, an etchant such as chlorine (CI2) can be added to the H2 gas during a plasma H2 operation during a PEALD cycle.

[0078] Simultaneous DED may also be referred to a blended DED, with the deposition and etch operations overlapping in time. Figure 6B also has an example of a molybdenum halide-based blended DED. Unlike a molybdenum oxyhalide such as MOO2CI2 or M00CI4, a molybdenum halide such as M0CI5 or MoFe will etch the deposited molybdenum. An example of a blended process may be to lower the H2 and / or increase the molybdenum halide flow to have net etch at the feature opening.

[0079] For a V-shape incoming structure, fill is less challenging and can use any appropriate ALD or CVD process, eitherthermal or plasma-enhanced. CVD processes include continuous flowAttorney Docket No. LAM1P074WO-12060-1WO and pulsed CVD processes. The subprocesses identified under "V-shaped" structures may be performed for any feature that is relatively easy to fill. In some embodiments, these subprocesses may be used as the final fill operation of a more challenging structure that has been partially filled.Molybdenum Deposition

[0080] Deposition of molybdenum as described herein involves reacting a Mo-containing precursor, also referred to as a molybdenum precursor. In some embodiments, a molybdenum halide compound as described above is used. In methods including surface treatment using a molybdenum halide compound, the same or different compound may be used for deposition.

[0081] In some embodiments, a Mo precursor is a molybdenum chloride (MoClx) compound also referred to as a molybdenum chloride precursor or MoClxprecursor. Molybdenum chloride precursors are given by the formula MoClx, where x is 2, 3, 4, 5, or 6, and include molybdenum dichloride (MoCI2), molybdenum trichloride (MoCU), molybdenum tetrachloride (M0CI4), molybdenum pentachloride (M0CI5), and molybdenum hexachloride (MoCk). In some embodiments, M0CI5 or MoCk are used. While the description chiefly refers to MoClxprecursors, in other embodiments, other molybdenum halide precursors may be used. Molybdenum halide precursors are given by the formula MoXz, where X is a halogen (fluorine (F), chlorine (Cl), bromine (Br), or iodine (I)) and z is 2, 3, 4, 5, or 6. Examples of MoXzprecursors include molybdenum fluoride (MoFe). In some embodiments, a non-fluorine-containing MoXzprecursor is used to prevent fluorine etch or incorporation. In some embodiments, a non-bromine- containing and / or a non-iodine-containing MoXzprecursor is used to prevent etch or bromine or iodine incorporation.

[0082] In some embodiments, the feature may be filled using a molybdenum oxyhalide precursor. Molybdenum oxyhalide precursors are given by the formula MoOyXz, where X is a halogen (fluorine (F), chlorine (Cl), bromine (Br), or iodine (I)), and y and 1 are numbers greater than 0 such that MoOyXzforms a stable compound. Examples of molybdenum oxyhalides include molybdenum dichloride dioxide (MOO2CI2), molybdenum tetrachloride oxide (MoOCU), molybdenum tetrafluoride oxide (MoOF4), molybdenum dibromide dioxide (MoChBrz), and the molybdenum iodides MOO2I, and MO4O11I. It should be understood that as used herein the term molybdenum oxyhalide precursor may refer to a molybdenum oxyhalide precursor as described above or a molybdenum-containing oxyhalide precursor that includes molybdenum, oxygen, a halide and one or more other elements. In some embodiments, molybdenum oxyhalide or molybdenum-containing oxyhalides may include multiple different halogens (e.g., F and Cl and / orAttorney Docket No. LAM1P074WO-12060-1WOI and / or Br, etc.). A feature may be filled with molybdenum using a MoXxprecursor, MoOyXzprecursor, or a combination thereof.

[0083] For deposition of molybdenum into the feature, the molybdenum precursor may be reacted with a co-reactant. Examples of co-reactants include hydrogen (H2), silane (SH-I4), diborane (B2H6), germane (GeF ), ammonia (NH3), and hydrazine (N2H4). Ammonia and hydrazine may be used to deposit molybdenum nitrides or molybdenum oxynitrides.

[0084] In some embodiments, deposition of molybdenum may use a plasma-based process. Gas may be fed into a remote or in-situ plasma generator to generate plasma species. Examples of gas that may be used to generate plasma may be a hydrogen-containing gas, such as H2, nitrogen-containing gas, such as nitrogen (N2) and other gases, such as Ar and NH3. The plasma species may be inert or react with the molybdenum precursor to form a film.

[0085] A feature may be filled with molybdenum by atomic layer deposition (ALD) or chemical vapor deposition (CVD). Thermal ALD or plasma enhanced ALD (PEALD) may be used. Similarly, thermal CVD or plasma enhanced CVD (PECVD) may be used.

[0086] ALD is a surface-mediated deposition technique in which doses of a precursor and a reactant are sequentially introduced into a deposition chamber. One or more cycles of sequential doses of a molybdenum precursor and reactant may be used to deposit Mo. For example, in the deposition of an initial molybdenum layer (e.g., as in operation 505 of Figure 5), M0CI5 may be used as a precursor and H2 as a reducing agent. Doses of M0CI5 and H2 are sequentially introduced into the deposition chamber with a purge gas, such as argon, flowed between. For ALD, the temperature of the substrate and the pressure of the chamber may be controlled. For example, the substrate may be heated between 200°C and 800°C, e.g., between 250°C and 550°C or between 300°C and 500°C between 350°C and 450°C. In some embodiments, the chamber may be pressurized between 10 Torr and 200 Torr, e.g., between 50 Torr and 90 Torr. In some embodiments, the temperature and / or pressure may be used to control the rate of reactions. In some embodiments, the temperature and / or pressure may be used to control selectivity.

[0087] In some embodiments, the Mo precursor is a molybdenum fluoride (MoFx) compound, also referred to as a molybdenum fluoride precursor or MoFxprecursor. Molybdenum chloride precursors are given by the formula MoFx, where x is 4, 5, or 6, and include molybdenum tetrafluoride (M0F4), molybdenum pentafluoride (M0F5), and molybdenum hexafluoride (MoFe).

[0088] MoFg can be advantageous as it has a boiling point of 34°C. Being a gas at standard pressure and 35°C allows MoFe to be delivered through a mass flow controller (MFC) at room temperature, without heating and without condensing and forming particles. However MoFe isAttorney Docket No. LAM1P074WO-12060-1WO an aggressive etchant and exposure to MoFe during a process can result in etching instead of or in addition to Mo deposition. In some embodiments, deposition using MoFe involves providing a flow of MoFe in a process gas with the MoFe at a molar concentration of 0.01% or less. Concentration may be significantly lower in some embodiments, for example, 0.008% or less, 0.005% or less, or 0.004% or less. These values can also be expressed as parts per million (ppm) of a gas: 100 ppm (100 MoFe molecules per 1 million gas particles (atoms, molecules)) or less, 80 ppm or less, or 40 ppm or less. At temperatures between 200°C and 650°C, for example, a molar concentration at or below 0.004% results in CVD deposition when flowed with H2 and argon. Higher temperatures may be used to favor the deposition reaction and allow higher concentrations of MoFe, e.g., up to 0.01%. In some embodiments, concentrations may be 0.0039% or .0035% or less. In some embodiments, the MoFe concentration is at least 0.00004% or at least 0.0001%. Concentration may be very low with an exposed metal surface to grow on, for example.

[0089] Deposition using MoFe with H2 as reducing agent occurs only at unusually low concentration. As an example, for 0.5 seem of MoFe, a total flow rate of 13,500 seem may be used, for a MoFe concentration of 0.0037%. Deposition using metal halides and hydrogen generally involves much higher concentrations. For example, deposition of molybdenum using molybdenum hexachloride and hydrogen can be performed using concentrations 5 to 10 times higher than those used for MoFe.

[0090] In some embodiments, MoFe may be used at higher concentrations and lower temperatures with a reducing agent that is stronger than that of hydrogen. Lower temperatures can reduce or prevent etching with MoFe; however, at low temperatures H2 may not result in deposition. Stronger reducing agents such silane, disilane, polysilanes and diborane may be used for deposition at lower temperatures (e.g., below 200°C). The resulting films may not be pure molybdenum and in some cases are more resistive than those deposited using H2 as the reducing agent. For these reasons they may not be appropriate for some applications.

[0091] In some embodiments, molybdenum fill may involve CVD. In a CVD process, the molybdenum precursor and reactant are in vapor phase together in the deposition chamber. Generally speaking, a CVD process fills a feature faster than an ALD process. In one example, the precursor may be a molybdenum oxychloride, such as MOO2CI2, and is flowed into the chamber with a reactant, such as H2. In this example, the wafer is simultaneously exposed to the precursor and reactant, which react and fill features with Mo. In one example, MoFe is flowed into the chamber with a reactant, such as H2. In this example, the wafer is simultaneously exposed to theAttorney Docket No. LAM1P074WO-12060-1WO precursor and reactant, which react and fill features with Mo.

[0092] In still some other embodiments, a feature may be filled using a pulsed CVD process. The pulsed CVD process continuously flows a reactant into a chamber while pulses of a precursor flow into the chamber. For example, H2 gas may be flowed into the chamber and is continuously flowing into the chamber while the molybdenum-containing precursor is intermittently flowing into the chamber. The temperature of the substrate and pressure in the chamber may be controlled during a CVD operation

[0093] Plasma-enhanced CVD may be used in which a plasma is ignited during the deposition. In a pulsed CVD process, a plasma may be ignited during deposition cycle or during, e.g., pulses of the hydrogen reactant. In some embodiments, a remote plasma may be used. The plasma may be remotely-generated or direct. Further it may be generated by any appropriate plasma generator including a capacitively-coupled plasma generator or an inductively-coupled plasma generators. A microwave plasma generator may be used.

[0094] Figure 6C shows an example of molybdenum deposition by an atomic layer deposition (ALD) process. In the example of Figure 6C, a substrate is exposed to a process gas including a molybdenum-containing precursor in an operation 601. A purge operation is then performed in an operation 603. An adsorbed layer of molybdenum-containing precursor remains, with the gas phase precursor removed. The substrate is then exposed to a reactant in an operation 605. This is typically a reducing agent, e.g., hydrogen. In plasma processes using a direct plasma, the plasma is ignited during this operation. In plasma processes using a direct plasma, reactant includes plasma species (e.g., hydrogen radicals) generated remotely. The reactant reacts with the adsorbed precursor to form a layer of molybdenum. A purge operation is then performed in an operation 607. Operations 601-607 may then be repeated until the molybdenum film is at a target thickness in an operation 609.

[0095] Modifications of the process described in Figure 6C can include exposure to the reactant as the first operation in each cycle, followed by a purge, exposure to the molybdenum-containing compound, and purge. Further modifications can include each cycle forming less than a monolayer. This can be performed by limiting the amount of one or both reactants. In some embodiments, the ALD process may not be strictly self-limiting. For example, one or both of the purge operations may be omitted or shortened such that some gas-phase reactant remains and reacts in the gas phase. This can increase deposition rate. Further modifications can include repeating operation 601 (with or without an intervening purge) prior to performing operation 605 within a cycle. In some embodiments, operation 605 is repeated one or more times withinAttorney Docket No. LAM1P074WO-12060-1WO a cycle. Such modifications facilitate diffusion through a feature. Still further, in some embodiments, the reactant may be, e.g., nitrogen-containing such that a molybdenum nitride or molybdenum oxynitride layer is formed.Selective deposition

[0096] Molybdenum may be selectively deposited into a feature using the methods described herein. Selective deposition refers to preferential deposition on a first material with respect to a second material. Molybdenum deposition and growth may be easier on a metal material relative to molybdenum deposition and growth on a dielectric material. For example, a feature may have a sidewall surface of SiO2and W bottom surface. In selective deposition, molybdenum is deposited into the feature and may grow on the W surface but not grow (or grow to a lesser extent) on the SiO2sidewall surfaces.

[0097] Process conditions such as the precursor gas, the reducing agent, process temperature, process pressure, and exposure time may affect the selectivity of the molybdenum film being deposited. Process temperatures for selective deposition of the molybdenum film may be between 200°C to 800°C, e.g., 250°C to 550°C, or 300°C to 500°C. At these temperatures, the molybdenum film is selectively deposited on conductive metal (e.g., W) or conductive metal compound surfaces (e.g., TiN) in a feature relative to dielectric surfaces.

[0098] Different precursor gases may have different process windows in which molybdenum film may be selectively deposited. Generally speaking, MoCk gas has a large process window, i.e., large temperature and pressure range, where the precursor gas retains its selectivity. For example, M0CI5 may be selectively deposited on a metal material with respect to a dielectric material where the process temperature is 200°C to 800°C, e.g., 250°C to 550°C, or 300°C to 500°C. Generally speaking, higher process temperatures and higher process pressures reduce the selectivity of the deposited gas. M0CI5 deposits selectively on metals, titanium nitride (TiN) and other conductive materials relative to dielectric materials at a wide range of temperatures.

[0099] M0CI5 may be reacted with different reactant to deposit a molybdenum film. Described below are examples of deposition of molybdenum film within a feature using a M0CI5 precursor and different process controls. In a first example, the M0CI5 precursor is reacted with a hydrogen (H2) reactant using the deposition methods described above. In the description herein, the metal precursors are reacted with H2as a co-reactant (also referred to as a hydrogen reactant or H2reactant). Other reactants may be used instead of hydrogen including other hydrogen-containing reactants such SiFU, B2He, NH3, as appropriate. Reactants such as B2He and / or SiFU are strongerAttorney Docket No. LAM1P074WO-12060-1WO reducing agents and generally show reduced selectivity. They can also result in higher resistivity. Thus, in some embodiments, using H2 as described herein is advantageous. As noted above, process temperatures for selective deposition of the molybdenum film from M0CI5 may be between 200°C to 800°C, e.g., 250°C to 550°C, or 300°C to 500°C. At these temperatures, the molybdenum film is selectively deposited on conductive metal or metal compound surfaces, such as a W or TiN surface, in a feature relative to dielectric surfaces. The molybdenum film grows from the locations where the conductive surfaces are located in a feature. If the conductive surface is W layer or a TiN plug at the bottom of the feature, the molybdenum film may be deposited and grown from the bottom of the feature. In a second example, the molybdenum film may be deposited usingthe M0CI5 precursor and the H2 reactant, but at highertemperatures, i.e., above 800°C. This process window may have the molybdenum film deposited on both the dielectric and conductive surfaces within the feature. The deposition of the molybdenum film on the dielectric surface may be used to create a barrierless molybdenum layer in the feature.

[0100] In some embodiments, selective deposition is performed using a MoFxprecursor. Molybdenum fluoride precursors are given by the formula MoFxas described above. As indicated above, MoFe can be advantageous for ease of delivery. Deposition of molybdenum from MoFe at the low concentrations disclosed above results in high (at least 100:1) selectivity of one elemental metal surfaces (e.g., W, Mo, Cu) relative to oxides and nitrides such as silicon oxide and titanium nitride. MoFe also deposits selectively on metals with respect to dielectric materials, though is less selective than M0CI5. As can be seen, after a delay, MoFe deposits on thermal oxide. Selectivity of molybdenum halides can also be affected by operating at conditions (e.g., concentration, temperature, etc.) at which the molybdenum halide also etches.

[0101] Selective deposition using a molybdenum oxyhalide precursor is much more difficult than using a molybdenum halide precursor. However, the surface treatments described above significantly improve selectivity of Mo deposition from MOO2CI2. As indicated above, examples of MoOyXz precursors include MOO2CI2, MoOC , M00F4, MoCbB^, MOO2I, and MO4O11I. The feature may be filled using ALD, plasma enhanced ALD, chemical vapor deposition (CVD), or plasma enhanced CVD. For ALD or CVD, H2may be the reducing agent. Molybdenum deposits more quickly using a molybdenum oxyhalide precursor than the MoClxprecursor used in the surface treatment. For example, a MoOyXzprecursor may deposit molybdenum at a deposition rate at least twice as fast as a MoClxprecursor for a non-plasma process.Attorney Docket No. LAM1P074WO-12060-1WONon-selective Deposition

[0102] The selectivity described above may be reduced or eliminated using plasma deposition in some embodiments, such that the molybdenum is deposited on different materials. This may be referred to as non-selective deposition. When ALD processes are used, the non-selective deposition may be conformal to the contours of surface. The plasma is generally an in-situ or direct plasma for non-selective deposition.

[0103] Examples of plasma processes include plasma-enhanced ALD (PEALD) or plasma enhanced CVD (PECVD) processes using a molybdenum halide precursor. In some embodiments, the molybdenum halide precursor is M0CI5 or MoFe. A molybdenum oxyhalide may also be used, with examples including MoC Ch or MoOCh. Hydrogen (H2) or other reducing agent may be used for the PEALD or PECVD deposition.

[0104] For PECVD deposition, the molybdenum precursor can be co-flowed with the reducing agent. For MoFe, the concentration of the MoFe is as described above, with the mixture flowed into a plasma generator. Remote or direct plasmas may be used. In some embodiments, a capacitively-coupled direct plasma that is generated in the chamber is employed.

[0105] Non-selective deposition may also be a thermal process using molybdenum oxyhalides. For example, thermal MOO2CI2 and H2 may be used to deposit a molybdenum layer non- selectively. Temperatures at or above 450°C may be used in for thermal deposition from MOO2CI2 and H2.

[0106] To reduce selectivity, an ALD process may be performed to deposit a Mo-containing nucleation layer. For nucleation layer deposition, a stronger reducing agent than hydrogen is employed. This can allow the film to grow on surfaces that face nucleation delay with hydrogen as reducing agent. As described further below, such a reducing agent can be a silicon-containing or boron-containing reducing agent such as silane (SiH4) or diborane (B2H6). Germanium- containing reducing agents (e.g., GeH4) may be used. These may be used to deposit an elemental molybdenum film. In other embodiments, a reducing agent such as ammonia (NH3) may be used. In such cases, the molybdenum layer may be a molybdenum nitride or molybdenum oxynitride layer, depending on the presence of oxygen in the molybdenum precursor. This oxynitride layer or nitride layer may be converted into an elemental molybdenum layer in the subsequent process.

[0107] When using MoFe, the concentration of MoFe in the MoFe dose may as described above, i.e., 0.01% or less, 0.008% or less, 0.005% or less, or 0.004% or less of the total gas flowed into the chamber. Alternatively, because a stronger reducing agent than hydrogen is used in theAttorney Docket No. LAM1P074WO-12060-1WO subsequent operation, a higher concentration (e.g., up to 0.1% molar) may be used during the MoF6. Some amount of a reducing agent may be present to suppress etching. As described above, this can be between 0.5% and 10% or between 1% and 9% H2. Another reducing agent may be included instead of or in addition to hydrogen. The balance is wholly or predominately argon or other inert gas. During the reducing agent dose, the dose is wholly or predominately the reducing agent, with some amount (e.g., up to 10%, or between 1% and 9%) being argon in some embodiments, and the remainder the reducing agent. After deposition of the nucleation layer, a bulk molybdenum layer can be deposited using H2 as a reducing agent by any of the methods described above, including thermal or plasma-enhanced ALD or CVD.

[0108] In addition to the molybdenum halides and molybdenum oxyhalides described herein, the molybdenum films may be deposited using organometallic and / or sulfur-containing precursors. Organometallic molybdenum-containing compounds and / or sulfur-containing molybdenum-containing compounds may be used as molybdenum precursors in some embodiments. Examples of these are given in PCT publication W02023250500, incorporated by reference herein.Nucleation Layer

[0109] In some embodiments, filling a feature can involve depositing a nucleation layer. A nucleation layer is a thin layer that supports bulk deposition. It may be conformal to the feature. In many embodiments, a nucleation layer is deposited by an ALD process. In some embodiments, a Mo nucleation layer is deposited using one or more of a boron-containing reducing agent (e.g., B2H6) or a silicon-containing reducing agent (e.g., SiHzr) as a co-reactant. For example, one or more S / Mo cycles or Mo / S cycles may be used to deposit a Mo nucleation layer. In another example, one or more B / Mo cycles or Mo / B cycles may be used to deposit a Mo nucleation layer on which a bulk Mo layer is deposited. B refers to a pulse of diborane or other boron-containing reducing agent and S to a pulse of silane or other silicon-containing reducing agent, such that S / Mo refers to a pulse of silane followed by a pulse of a Mo-containing precursor. B / Mo and S / Mo cycles (or Mo / B and / or Mo / S) may both be used to deposit a Mo nucleation layer, e.g., x(B / Mo) + y(S / Mo), with x and y being integers. Examples of boron-containing reactants include diborane (B2H6), alkyl boranes, alkyl boron, aminoboranes (CH3)2NB(CH2)2, carboranes such as C2BnHn+2, and other boranes. Examples of boranes include BnHn+4, BnHn+6, BnHn+8, BnHm, where n is an integer from 1 to 10, and m is a different integer than m. Examples of silicon-containing reducing agents including silane (SiH4) and other silanes such as disilane (Si2He).

[0110] In some embodiments, deposition of a Mo nucleation layer may involve using a non-Attorney Docket No. LAM1P074WO-12060-1WO oxygen-containing precursor, e.g., molybdenum hexafluoride (MoFe) or molybdenum pentachloride (M0CI5). Oxygen in oxygen-containing precursors may react with a silicon- or boron-containing reducing agent to form MoSixOyor MoBxOy, which are impure, high resistivity films. In some embodiments, oxygen-containing precursors may be used for nucleation layer deposition with oxygen incorporation minimized. Oxygen incorporation can be minimized by high reducing agent flows (e.g., greater than 100:1 volumetric flow rate of reducing agent to oxygen-containing Mo precursor).

[0111] In some embodiments, H2 may be used as a reducing gas for Mo nucleation layer deposition instead of a boron-containing or silicon-containing reducing gas. Example thicknesses for deposition of a Mo nucleation layer range from 5 A to 30 A. Films at the lower end of this range may not be continuous; however, as long as they can help initiate continuous bulk Mo growth, the thickness may be sufficient.

[0112] In some embodiments, the reducing agent pulses during deposition of a nucleation or bulk Mo layer may be done at lower substrate temperatures than the Mo precursor pulses. For example, or B2H6 or a SiF (or other boron- or silicon-containing reducing agent) pulse may be performed at a temperature below 300°C, with the Mo pulse at temperatures greater than 300°C.

[0113] In some embodiments, the reducing agent is NH3 or other nitrogen-containing reducing agents such as hydrazine (N2H4). NH3 chemisorption on dielectrics is more favorable than that of H2. In some embodiments, the reducing agent and precursor are selected such that they react without reducing agent dissociation. NH3 reacts with metal oxychlorides and metal chlorides without dissociation. This is in contrast to, for example, ALD from metal oxychlorides that use H2as a reducing agent; H2 dissociates on the surface to form adsorbed atomic hydrogen, which results in very low concentrations of reactive species and low surface coverage during initial nucleation of metal on the dielectric surface. By using NH3 and metal oxychloride or metal chloride precursors, nucleation delay is reduced or eliminated at deposition temperatures up to hundreds of degrees lower than used by H2 reduction of the same metal precursors.

[0114] In some embodiments, the reducing agent may be a boron-containing or silicon- containing reducing agent such as B2He or SiF . These reducing agents may be used with metal chloride precursors, with metal oxychlorides; however, the B2H6 and SiFU may react with water formed as a byproduct during the ALD process and form solid B2O3 and SiCU. These are insulating and can remain in the film, increasing resistivity. Use of NH3 also has improved adhesion over B2H6 and SiFU ALD processes on certain surfaces including AI2O3. The resulting nucleation layer is generally not a pure elemental film but a metal nitride or metal oxynitride film. In someAttorney Docket No. LAM1P074WO-12060-1WO embodiments, there may be residual chlorine or fluorine from the deposition, particularly if the deposition is performed at low temperatures. In some embodiments, there may be no more than a trace amount of residual chlorine or fluorine. In some embodiments, the nucleation layer is an amorphous layer. Impurities in the film (e.g., oxygen, NH3, chlorine, or other halogens) facilitate the growth of an amorphous microstructure. In some embodiments, the nucleation layer as deposited is an amorphous molybdenum oxynitride layer or an amorphous molybdenum nitride layer. The amorphous character templates large grain growth in the subsequently deposited conductor. The surface energy of nitride or oxynitride relative to an oxide surface is much more favorable than that of a metal on an oxide surface, facilitating formation of a continuous and smooth film on the dielectric. This allows formation of thin, continuous layers. Example thicknesses of the nucleation layer range from 5-30A as deposited. Depending on the temperature, this may be about 5-50 ALD cycles, for example.Fill materials

[0115] According to various embodiments, a fill material can be molybdenum or another conductive material. For example, a molybdenum or molybdenum-containing liner may be formed in feature with another metal used for final fill. Deposition of other metals is described below.

[0116] Cobalt-containing films can be deposited using a variety of cobalt precursors, where cobalt may be in +1, +2 or +3 oxidation states. Examples of cobalt precursors include cobalt acetate, cobalt acetylacetonates (e.g., cobalt (III) bis(acetylacetonate)), cobalt amidinates (e.g., bis(N-t-butyl-N'-ethylpropanimidamidato)cobalt(ll),) cobaltocene, and carbonyl-containing cobalt precursors (e.g., cobalt tricarbonyl nitrosyl, and cyclopentadienylcobalt dicarbonyl). An example of a halogen-containing cobalt precursor is CoC CFMEDA), where TMEDA is / V, / V, / V', / V'tetramethylethylenediamine. Ruthenium-containing films metal can be deposited, for example, using vaporizable ruthenium precursors, such as bis(ethylcyclopentadienyl)ruthenium(ll), bis( penta methylcyclopentadienyl) ruthenium, ruthenocene, and cyclopentadienylpropylcyclopentadienylruthenium(ll). Tungsten-containing films can be deposited using a variety of volatile precursors. In some embodiments halogencontaining tungsten precursors, such as WXx, where X is a halogen (e.g., F, Cl, Br, and / or I) and x is from 2 to 6, are used. In some embodiments tungsten chloride is used. Tungsten chloride includes tungsten pentachloride (WCI5), tungsten hexachloride (WCk), tungsten tetrachloride (WCI4), tungsten dichloride (WCI2), and mixtures thereof. In other examples tungsten fluoride, such as tungsten hexafluoride may be used. In some embodiments, other useful precursorsAttorney Docket No. LAM1P074WO-12060-1WO include vanadium-containing precursors such as tetrakis(dimethylamino)vanadium, tris(dimethylamino)cyclopentadienylvanadium, tetrakis(ethylmethylamino)vanadium; niobium- containing precursors such as (tert-butylimido)bis(diethylamino)niobium, (tert- butylimido)bis(dimethylamino) niobium and (tert-butylimido)bis(ethylmethylamino)niobium; tantalum-containing precursors such as tert-butylimidotris(dimethylamido)tantalunn and tantalum pentachloride; iron-containing precursors such as iron (III) tert-butoxide dimer, ferrocene and iron pentcarbonyl; nickel-containing precursors such as allyl(cyclopentadienyl)nickel(ll) and nickel(ll) bis(acetylacetonate); zinc-containing precursors such as zinc acetate and diethylzinc; and chromium-containing precursors such as chromium carbonyl and bis(cyclopentadienyl)chromium (II).Metal Halide Treatments

[0117] Another aspect of the disclosure relates to metal halide treatments. In some embodiments, Embodiments of the disclosure relate to metal halide treatments. The metal halide treatments may be used in embodiments of the methods of Figures 3A and 3B, for example. In other embodiments, they may be used as a pretreatment before processing operations such as deposition with or without prior treatments such as oxidizing and / or reducing plasmas.

[0118] A metal halide treatment can involve sequences of metal halides pulses separated by purges. The table below shows examples of materials to be treated, corresponding products of for treatment with M0CI5, and the change in Gibbs free energy (dG) for the products.Attorney Docket No. LAM1P074WO-12060-1WO

[0119] Thermodynamically favorable reactions may not have favorable kinetics, but comparing the change in Gibbs free energy can be used to approximate relative etching ease. Notably, etching of dielectrics such SiC>2 and AI2O3 is unfavorable. In the methods, the metal halide treatment can be used to selectively treat surfaces such as W, TIN, and their oxides without damaging dielectric surfaces on the substrate or coated chamber surfaces. M0CI5 and other metal halide treatments are selective to metal oxides. Figure 6D shows etch rates of various materials MoCIs / Ar cycles. Purging can be important to remove chlorinated surfaces. That is, without purging, a surface can become chlorinated and prevent further adsorption.Apparatus

[0120] Figure 7 depicts a schematic illustration of an embodiment of an ALD process station 700 having a process chamber 702 for maintaining a low-pressure environment. In some embodiments, a plurality of ALD process stations may be included in a common low-pressure process tool environment. For example, Figures 8A and 8B depict embodiments of a system 800 including a multi-station processing tool. In some embodiments, one or more hardware parameters of ALD process station 700, including those discussed in detail below, may be adjusted programmatically by one or more computer controllers 829. In some other embodiments, a process chamber may be a single station chamber.

[0121] ALD process station 700 fluidly communicates with reactant delivery system 701a for delivering process gases to a distribution showerhead 706. Reactant delivery system 701a includes a mixing vessel 704 for blending and / or conditioning process gases, such as a Mo precursor-containing gas, a hydrogen-containing gas, an argon or other carrier gas, or other reactant-containing gas, for delivery to showerhead 706. One or more mixing vessel inlet valves 720 may control introduction of process gases to mixing vessel 704. In various embodiments, deposition of an initial Mo layer is performed in process station 700 and in some embodiments, other operations such as in-situ clean or Mo gap fill may be performed in the same or another station of the multi-station processing tool of the system 800 as further described below with respect to Figure 8A.Attorney Docket No. LAM1P074WO-12060-1WO

[0122] As an example, the embodiment of Figure 7 includes a vaporization point 703 for vaporizing liquid reactant to be supplied to the mixing vessel 704. In some embodiments, vaporization point 703 may be a heated vaporizer. In some embodiments, a liquid precursor or liquid reactant may be vaporized at a liquid injector (not shown). For example, a liquid injector may inject pulses of a liquid reactant into a carrier gas stream upstream of the mixing vessel 704. In one embodiment, a liquid injector may vaporize the reactant by flashing the liquid from a higher pressure to a lower pressure. In another example, a liquid injector may atomize the liquid into dispersed microdroplets that are subsequently vaporized in a heated delivery pipe. Smaller droplets may vaporize faster than larger droplets, reducing a delay between liquid injection and complete vaporization. Faster vaporization may reduce a length of piping downstream from vaporization point 703. In one scenario, a liquid injector may be mounted directly to mixing vessel 704. In another scenario, a liquid injector may be mounted directly to showerhead 706.

[0123] Reactant delivery system 701a may also include one or more solid precursor delivery components including one or more on-board ampoules 713 and / or bulk delivery components 715.

[0124] In some embodiments, a liquid flow controller (LFC) upstream of vaporization point 703 may be provided for controlling a mass flow of liquid for vaporization and delivery to process chamber 702. For example, the LFC may include a thermal mass flow meter (MFM) located downstream of the LFC. A plunger valve of the LFC may then be adjusted responsive to feedback control signals provided by a proportional-integral-derivative (PID) controller in electrical communication with the MFM. However, it may take one second or more to stabilize liquid flow using feedback control. This may extend a time for dosing a liquid reactant. Thus, in some embodiments, the LFC may be dynamically switched between a feedback control mode and a direct control mode. In some embodiments, this may be performed by disabling a sense tube of the LFC and the PID controller.

[0125] Showerhead 706 distributes process gases toward substrate 712. In the embodiment shown in Figure 7, the substrate 712 is located beneath showerhead 706 and is shown resting on a pedestal 708. Showerhead 706 may have any suitable shape and may have any suitable number and arrangement of ports for distributing process gases to substrate 712.

[0126] In some embodiments, pedestal 708 may be raised or lowered to expose substrate 712 to a volume between the substrate 712 and the showerhead 706. In some embodiments.Attorney Docket No. LAM1P074WO-12060-1WO pedestal 708 may be temperature controlled via heater 710. Pedestal 708 may be set to any suitable temperature, such as between about 250°C and about 800°C during operations for performing various disclosed embodiments. It will be appreciated that, in some embodiments, pedestal height may be adjusted programmatically by a suitable computer controller 750. At the conclusion of a process phase, pedestal 708 may be lowered during another substrate transfer phase to allow removal of substrate 712 from pedestal 708.

[0127] In some embodiments, a position of showerhead 706 may be adjusted relative to pedestal 708 to vary a volume between the substrate 712 and the showerhead 706. Further, it will be appreciated that a vertical position of pedestal 708 and / or showerhead 706 may be varied by any suitable mechanism within the scope of the present disclosure. In some embodiments, pedestal 708 may include a rotational axis for rotating an orientation of substrate 712. It will be appreciated that, in some embodiments, one or more of these example adjustments may be performed programmatically by one or more suitable computer controllers 750. The computer controller 750 may include any of the features described below with respect to controller 750 of Figure 7.

[0128] In some embodiments where plasma may be used as discussed above, showerhead 706 and pedestal 708 electrically communicate with a radio frequency (RF) power supply 714 and matching network 77 for powering a plasma. In some embodiments, the plasma energy may be controlled by controlling one or more of a process station pressure, a gas concentration, an RF source power, an RF source frequency, and a plasma power pulse timing. For example, RF power supply 714 and matching network 716 may be operated at any suitable power to form a plasma having a desired composition of radical species. Likewise, RF power supply 714 may provide RF power of any suitable frequency. In some embodiments, RF power supply 714 may be configured to control high- and low-frequency RF power sources independently of one another. Example low-frequency RF frequencies may include, but are not limited to, frequencies between 0 kHz and 900 kHz. Example high-frequency RF frequencies may include, but are not limited to, frequencies between 1.8 MHz and 2.45 GHz, or greater than about 13.56 MHz, or greater than 27 MHz, or greaterthan 80 MHz, or greater than 60 MHz. It will be appreciated that any suitable parameters may be modulated discretely or continuously to provide plasma energy forthe surface reactions.

[0129] In some embodiments, the plasma may be monitored in-situ by one or more plasma monitors. In one scenario, plasma power may be monitored by one or more voltage, currentAttorney Docket No. LAM1P074WO-12060-1WO sensors (e.g., VI probes). In another scenario, plasma density and / or process gas concentration may be measured by one or more optical emission spectroscopy sensors (OES). In some embodiments, one or more plasma parameters may be programmatically adjusted based on measurements from such in-situ plasma monitors. For example, an OES sensor may be used in a feedback loop for providing programmatic control of plasma power. It will be appreciated that, in some embodiments, other monitors may be used to monitor the plasma and other process characteristics. Such monitors may include, but are not limited to, infrared (IR) monitors, acoustic monitors, and pressure transducers.

[0130] In some embodiments, instructions for a controller 750 may be provided via input / output control (IOC) sequencing instructions. In one example, the instructions for setting conditions for a process phase may be included in a corresponding recipe phase of a process recipe. In some cases, process recipe phases may be sequentially arranged, so that all instructions for a process phase are executed concurrently with that process phase. In some embodiments, instructions for setting one or more reactor parameters may be included in a recipe phase. For example, a first recipe phase may include instructions for setting a flow rate of an oxidizing plasma process gas, instructions for igniting a plasma, and time delay instructions for the first recipe phase. A second recipe phase may include instructions for modulating a flow rate of a metal halide gas, instructions for modulating the flow rate of a carrier or purge gas, and time delay instructions for the second recipe phase. It will be appreciated that these recipe phases may be further subdivided and / or iterated in any suitable way within the scope of the present disclosure.

[0131] Further, in some embodiments, pressure control for process station 700 may be provided by butterfly valve 718. As shown in the embodiment of Figure 7, butterfly valve 718 throttles a vacuum provided by a downstream vacuum pump (not shown). However, in some embodiments, pressure control of process station 700 may also be adjusted by varying a flow rate of one or more gases introduced to the process station 700.

[0132] Figure 8A and Figure 8B show examples of processing systems. Figure 8A shows an example of a processing system including multiple chambers. The system 800 includes a transfer module 803. The transfer module 803 provides a clean, vacuum environment to minimize risk of contamination of substrates being processed as they are moved between various modules. Mounted on the transfer module 803 is a multi-station chamber 809 capable of performing in- situ clean and / or ALD processes described above. Surface treatment and / or initial Mo layerAttorney Docket No. LAM1P074WO-12060-1WO deposition may be performed in the same or different station or chamber as the subsequent Mo gap fill.

[0133] Chamber 809 may include multiple stations 811, 813, 815, and 88 that may sequentially perform operations in accordance with disclosed embodiments. For example, chamber 809 may be configured such that station 811 performs an oxidizing plasma treatment. Station 813 may be configured to perform a reducing plasma treatment, station 815 may be configured to perform a metal halide treatment, and station 817 may be configured to perform ALD of bulk Mo using an molybdenum oxyhalide precursor and H2. In another example, chamber 809 may be configured such that station 811 performs in-situ pretreatment, station 813 performs ALD of an initial Mo layer, station 813 selectively treatsthe layer, and 814 deposition of bulk Mo. In another example, the chamber 809 may be configured to do parallel processing of substrates, with each station performing multiple processes sequentially.

[0134] Two or more stations may be included in a multi-station chamber, e.g., 2-6, with the operations appropriately distributed. For example, a two-station chamber may be configured to perform ALD of an initial Mo layer in a first station followed by ALD of bulk Mo in a second station. A four-station chamber may be configured to perform ALD of an initial Mo layer in a first station, plasma treatment (e.g., oxidation) in a second station, etching in a third station, followed by ALD of bulk Mo in a fourth station. Stations may include a heated pedestal or substrate support, one or more gas inlets or showerhead or dispersion plate.

[0135] Stations may include a heated pedestal or substrate support, one or more gas inlets or showerhead or dispersion plate.

[0136] Also mounted on the transfer module 803 may be one or more single or multi-station modules 807. In some embodiments, a preclean as described above may be performed in a module 807, after which the substrate is transferred under vacuum to another module (e.g., another module 807 or chamber 809) for ALD. In another example, a module for selective treatment of a film may be mounted on the transfer module.

[0137] The system 800 also includes one or more wafer source modules 801, where wafers are stored before and after processing. An atmospheric robot (not shown) in the atmospheric transfer chamber 819 may first remove wafers from the source modules 801 to loadlocks 821. A waferAttorney Docket No. LAM1P074WO-12060-1WO transfer device (generally a robot arm unit) in the transfer module 803 moves the wafers from loadlocks 821 to and amon the modules mounted on the transfer module 803.

[0138] Referring to Figure 6B, for example, in some embodiments, chamber 809 is configured to perform pre-treatment, selective fill, conformal liner deposition, and final fill. In one example, station 811 is configured to perform selective fill, station 813 is configured to perform conformal liner deposition, station 815 is configured to perform etch, and station 817 is configured to perform final fill. In another example, station 811 is configured to perform oxidizing plasma pretreatment, station 813 is configured to perform metal halide pre-treatment, station 813 is configured to selective fill, and station 815 is configured to perform final fill.

[0139] Chamber 809 may have one or more of the following features to enable single chamber metallization processes:Individually addressable plasma power generators associated with each station;Individually addressable reactant inputs associated with each station;Multi-plenum showerheads on each station;Dual solid precursor delivery systems.

[0140] Solid precursor delivery systems may include bulk delivery systems and / or on-board ampoules. Figure 8B is an embodiment of a system 800. The system 800 in Figure 8B has wafer source modules 801, a transfer module 803, atmospheric transfer chamber 819, and loadlocks 821, as described above with reference to Figure 8A. The system in Figure 8B has three single station modules 857a-875c. The system 800 may be configured to sequentially perform operations in accordance with disclosed embodiments. For example, the single station modules 857a-857c may be configured so that a first module 857a performs a pre-treatment, a second module 857b performs ALD of an initial Mo layer using a molybdenum halide precursor, and a third module 857c performs ALD of bulk Mo using a molybdenum oxyhalide precursor. In this example, an in-situ pre-treatment operation may be optionally performed in second module 857b instead of or in addition to a pre-treatment in first module 857a. In another example, the single station modules 857a-857c may be configured so that a first module 857a performs a deposition of an initial metal layer, a second module 857b performs selective treatment, and a third module 857c performs ALD of bulk Mo using a molybdenum oxyhalide precursor. In yet another example,Attorney Docket No. LAM1P074WO-12060-1WO one module may be configured for deposition, another module for selective treatment, and another module for etch.

[0141] Stations may include a heated pedestal or substrate support, one or more gas inlets or showerhead or dispersion plate as described above with reference to Figure 7.

[0142] Returning to Figure 8A and 8B, in various embodiments, a system controller 829 is employed to control process conditions during deposition. The controller 829 will typically include one or more memory devices and one or more processors. A processor may include a CPU or computer, analog and / or digital input / output connections, stepper motor controller boards, etc. Such a system controller may be employed in control of any of the processes and apparatus described herein.

[0143] The controller 829 may control all the activities of the apparatus. The system controller 829 executes system control software, including sets of instructions for controlling the timing, mixture of gases, chamber pressure, chamber temperature, wafer temperature, radio frequency (RF) power levels, wafer chuck or pedestal position, and other parameters of a particular process. Other computer programs stored on memory devices associated with the controller 829 may be employed in some embodiments.

[0144] Typically, there will be a user interface associated with the controller 829. The user interface may include a display screen, graphical software displays of the apparatus and / or process conditions, and user input devices such as pointing devices, keyboards, touch screens, microphones, etc.

[0145] System control logic may be configured in any suitable way. In general, the logic can be designed or configured in hardware and / or software. The instructions for controlling the drive circuitry may be hard coded or provided as software. The instructions may be provided by "programming." Such programming is understood to include logic of any form, including hard coded logic in digital signal processors, application-specific integrated circuits, and other devices which have specific algorithms implemented as hardware. Programming is also understood to include software or firmware instructions that may be executed on a general-purpose processor. System control software may be coded in any suitable computer readable programming language.

[0146] The computer program code for controlling the Mo precursor pulses, hydrogen pulses, and argon flow, and other processes in a process sequence can be written in any conventionalAttorney Docket No. LAM1P074WO-12060-1WO computer readable programming language: for example, assembly language, C, C++, Pascal, Fortran, or others. Compiled object code or script is executed by the processor to perform the tasks identified in the program. Also as indicated, the program code may be hard coded.

[0147] 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 may be entered utilizing the user interface.

[0148] Signals for monitoring the process may be provided by analog and / or digital input connections of the system controller 829. The signals for controlling the process are output on the analog and digital output connections of the deposition apparatus.

[0149] The system software may be designed or configured in many ways. For example, various chamber component subroutines or control objects may be written to control operation of the chamber components necessary to carry out the deposition processes in accordance with 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.

[0150] In some implementations, a controller 829 is part of a system, which may be part of the above-described examples. Such systems can include semiconductor processing equipment, including a processing tool or tools, chamber or chambers, a platform or platforms for processing, and / or specific processing components (a wafer pedestal, a gas flow system, etc.). These systems may be integrated with electronics for controlling their operation before, during, and after processing of a semiconductor wafer or substrate. The electronics may be referred to as the "controller," which may control various components or subparts of the system or systems. The controller 829, depending on the processing requirements and / or the type of system, may be programmed to control any of the processes disclosed herein, includingthe delivery of processing 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, positional and operation settings, wafer transfers into and out of a tool and other transfer tools and / or load locks connected to or interfaced with a specific system.Attorney Docket No. LAM1P074WO-12060-1WO

[0151] Broadly speaking, the controller may be defined as electronics having various integrated circuits, logic, memory, and / or software that receive instructions, issue instructions, control operation, enable cleaning operations, enable endpoint measurements, and the like. The 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, or 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), defining operational parameters for carrying out a particular process on or for a semiconductor wafer or to a system. The operational parameters may, in some embodiments, be part of a recipe defined by process engineers to accomplish one or more processing steps during the fabrication of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or dies of a wafer.

[0152] The controller 829, in some implementations, may be a part of or coupled to a computer that is integrated with, coupled to the system, otherwise networked to the system, or a combination thereof. For example, the controller 829 may be in the "cloud" or all or a part of a fab host computer system, which can allow for remote access of the wafer processing. The computer may enable remote access to the system to monitor current progress of fabrication operations, examine a history of past fabrication operations, examine trends or performance metrics from a plurality of fabrication operations, to change parameters of current processing, to set processing steps to follow a current processing, or to start a new process. In some examples, a remote computer (e.g. a server) can provide process recipes to a system over a network, which may include a local network or the Internet. The remote computer may include a user interface that enables entry or programming of parameters and / or settings, which are then communicated to the system from the remote computer. In some examples, the controller receives instructions in the form of data, which specify parameters for each of the processing steps to be performed during one or more operations. The parameters may be specific to the type of process to be performed and the type of tool that the controller is configured to interface with or control. Thus, as described above, the controller may be distributed, such as by including one or more discrete controllers that are networked together and working towards a common purpose, such as the processes and controls described herein. An example of a distributed controllerfor such purposes would be one or more integrated circuits on a chamber in communication with one or moreAttorney Docket No. LAM1P074WO-12060-1WO integrated circuits located remotely (such as at the platform level or as part of a remote computer) that combine to control a process on the chamber.

[0153] Without limitation, example systems may include a plasma etch chamber or module, a deposition chamber or module, a spin-rinse chamber or module, a metal plating chamber or module, a clean chamber or module, a bevel edge etch chamber or module, a 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 track chamber or module, and any other semiconductor processing systems that may be associated or used in the fabrication and / or manufacturing of semiconductor wafers.

[0154] As noted above, depending on the process step or steps to be performed by the tool, the controller might communicate with one or more of other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, neighboring tools, tools located throughout a factory, a main computer, another controller, or tools used in material transport that bring containers of wafers to and from tool locations and / or load ports in a semiconductor manufacturing factory.

[0155] The controller 829 may include various programs. A substrate positioning program may include program code for controlling chamber components that are used to load the substrate onto a pedestal or chuck and to control the spacing between the substrate and other parts of the chamber such as a gas inlet. A substrate tilt and rotation program may include for tilt and rotation. A process gas control program may include code for controlling gas composition, flow rates, pulse times, and optionally for flowing gas into the chamber prior to deposition in order to stabilize the pressure in the chamber. A pressure control program may include code for controlling the pressure in the chamber by regulating, e.g., a throttle valve in the exhaust system of the chamber. A heater control program may include code for controlling the current to a heating unit that is used to heat the substrate. Alternatively, the heater control program may control delivery of a heat transfer gas such as helium to the wafer chuck.

[0156] Examples of chamber sensors that may be monitored during deposition include mass flow controllers, pressure sensors such as manometers, and thermocouples located in the pedestal or chuck. Appropriately programmed feedback and control algorithms may be used with data from these sensors to maintain desired process conditions.Attorney Docket No. LAM1P074WO-12060-1WO

[0157] The foregoing describes implementation of disclosed embodiments in a single or multichamber semiconductor processing tool. The apparatus and process described herein may be used in conjunction with lithographic patterning tools or processes, for example, for the fabrication or manufacture of semiconductor devices, displays, LEDs, photovoltaic panels, and the like. Typically, though not necessarily, such tools / processes will be used or conducted together in a common fabrication facility. Lithographic patterning of a film typically includes some or all of the following steps, each step provided with a number of possible tools: (1) application of photoresist on a workpiece, i.e., substrate, using a spin-on or spray-on tool; (2) curing of photoresist using a hot plate or furnace or UV curing tool; (3) exposing the photoresist to visible or UV or x-ray light with a tool such as a wafer stepper; (4) developing the resist so as to selectively remove resist and thereby pattern it using a tool such as a wet bench; (5) transferring the resist pattern into an underlying film or workpiece by using a dry or plasma-assisted etching tool; and (6) removing the resist using a tool such as an RF or microwave plasma resist stripper.

Claims

Attorney Docket No. LAM1P074WO-12060-1WOCLAIMSWhat is claimed is:

1. A method comprising: a) providing a substrate including a feature to a chamber, wherein the feature is formed within a layer on the substrate and is surrounded by a field region and comprises a bottom surface and sidewall surfaces that extend from the field region to the bottom surface, wherein the sidewall surfaces are dielectric surfaces and the bottom surface is a conductive metal surface or an oxide thereof; b) exposing the substrate to an oxidizing plasma; and c) after (b), exposingthe substrate to one or both of a reducing plasma and a non-plasma metal halide treatment.

2. The method of claim 1, wherein the feature in (a) includes carbon-containing residue and (b) removes the carbon-containing residue.

3. The method of claim 1, wherein the oxidizing plasma is generated from a process gas comprising an oxygen source and hydrogen (H2).

4. The method of claim 3, wherein a volumetric ratio of the H2 to the oxygen source is at least 2:1.

5. The method of claim 1, further comprising, after (c), (d) filling the feature with molybdenum.

6. The method of claim 5, wherein (b)-(d) are performed in the chamber.

7. The method of claim 1, wherein (c) comprises exposingthe substrate to a reducing plasma followed by a non-plasma metal halide treatment.

8. The method of claim 1, wherein (c) comprises exposing the substrate to reducing plasma only.

9. The method of claim 1, wherein (c) comprises exposing the substrate to a non-plasma metal halide treatment only.

10. The method of claim 1, wherein (c) comprises the non-plasma metal halide treatment and the non-plasma metal halide treatment removes terminal groups from the bottom surface to leave a pure conductive metal surface.

11. The method of claim 10, where no metal is deposited during the non-plasma metal halide treatment.Attorney Docket No. LAM1P074WO-12060-1WO12. The method of claim 1, wherein the oxidizing plasma is formed in a plasma generator remote to the chamber.

13. The method of claim 1, wherein the oxidizing plasma is formed in the chamber.

14. An apparatus comprising: a multi-station chamber, wherein each station comprises a substrate support configured to support a substrate, a showerhead configured to inlet gases to a volume above substrate support, and at least one of the stations further comprises a plasma generator configured to generate a plasma between the substrate support and showerhead; and a controller having instructions for: co-flowing hydrogen (H2) and an oxygen-containing gas to a first station housing the substrate; while the substrate is in the first station, generating an oxidizing plasma in the first stationtransferring the substrate to a second station; and while the substrate is in the second station, inletting a metal halide to the second station.

15. The apparatus of claim 14, wherein the controller further comprises instructions for generating a reducing plasma in a station housing the substrate.

16. The apparatus of claim 15, wherein the instructions for generating the reducing plasma comprise instructions for generating the reducing plasma after generating the oxidizing plasma.

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