Method for forming impurity free metal alloy film

Abstract

To provide methods of depositing such films with minimal electronegative residue.SOLUTION: The method comprises: exposing at least a portion of the substrate to a first halide precursor including a compound of general formula (I) MQzRm (I) where M is a metal, Q is a halogen selected from Cl, Br, F or I; exposing at least a portion of the substrate to an organosilane reactant including a compound of general formula (II) or general formula (III); exposing to a second halide precursor including a compound of general formula (I); and exposing to an organosilane reactant including a compound of general formula (II) or general formula (III).SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention generally relates to a method for atomic layer deposition (ALD) of metal films. In particular, embodiments of the present invention are directed to heat-only based ALD deposition.

Background Art

[0002] Transistors are important components of most integrated circuits. Since the drive current of a transistor, and thus its speed, is proportional to the gate width of the transistor, generally, faster transistors require larger gate widths. Thus, there is a trade-off between the size and speed of a transistor, and "fin" field effect transistors (finFETs) have been developed to address the conflicting goals of having transistors with maximum drive current and minimum size. FinFETs are characterized by a fin-shaped channel region that significantly increases the transistor size without significantly increasing the installation area of the transistor, and are currently used in many integrated circuits. However, finFETs have their own drawbacks.

[0003] As the feature size of transistor devices continues to shrink to achieve higher circuit density and performance, there is a need for improvement in transistor device structures that improve electrostatic coupling and reduce adverse effects such as parasitic capacitance and leakage at off-state. Examples of transistor device structures include planar structures, fin field effect transistor (FinFET) structures, and horizontal gate all around (hGAA) structures. The hGAA device structure includes a plurality of lattice-matched channels suspended in a stacked configuration and connected by source / drain regions. The hGAA structure is considered to provide good electrostatic control and can find wide applications in complementary metal oxide semiconductor (CMOS) wafer manufacturing.

[0004] Work function metals have attracted great interest in the applications of metal-oxide-semiconductor (MOS) transistors. As candidates for the n-metal (work function metal) of MOS transistors, metal films such as tantalum carbide (TaC), titanium carbide (TiC), titanium aluminum carbide (TiAlC), and titanium aluminum (TiAl) have been evaluated.

[0005] Generally, the effective work function (WF) of metals and their alloys is defined by the effective electronegativity. Metals with higher electropositivity exhibit the work function of n-type metal-oxide-semiconductor (N-MOS). The most widely used N-metal films include titanium (Ti), aluminum (Al), hafnium (Hf), and lanthanum (La). There are no feasible options for depositing these pure metal films without plasma. The plasma process is generally not desirable for transistor manufacturing because the plasma can have a harmful effect on previously deposited films and the resulting devices. Therefore, there is a need in the art for a method of depositing such films with minimal electrically negative residues. SUMMARY OF THE INVENTION

[0006] One or more embodiments of the present disclosure are directed to a method of depositing a film. In one or more embodiments, the method includes exposing at least a portion of a substrate surface to a halide precursor comprising a compound having the general formula (I) MQ z R m (I) (wherein M is a metal, Q is a halogen selected from Cl, Br, F, or I, z is from 1 to 6, R is selected from alkyl, CO, cyclopentadienyl, amidinato, diazadiene, or amidate, and m is from 0 to 6), and exposing at least a portion of the substrate surface to a compound of general formula (II) or general formula (III) TIFF2025081314000002.tif66170 (wherein R 1 、R 2 、R 3 、R 4 、R 5 、R 6 、R 7 、R8 , R a , R b , R c , R d , R e , and R f are independently selected from hydrogen (H), substituted alkyl, or unsubstituted alkyl, and the X, Y, X', and Y organosilane reactants include exposing the organosilane reactant to a compound independently selected from nitrogen (N) and carbon (C)), and depositing a carbon - substantially - free metal film on the substrate surface.

[0007] Additional embodiments of the present disclosure are directed to electronic devices. In one or more embodiments, the gate stack includes a high - dielectric - constant dielectric layer on a substrate, a first titanium nitride layer on the high - dielectric - constant dielectric layer, a work - function layer on the first titanium nitride layer, and a second titanium nitride layer on the work - function layer, and the work - function layer includes a carbon - substantially - free metal film.

[0008] Further embodiments of the present disclosure are directed to a non - transitory computer - readable medium including instructions that, when executed by a controller of a processing chamber, cause the processing chamber to perform an operation of flowing a halide precursor into a processing volume of the processing chamber having a substrate, the halide precursor having the general formula (I) MQ z R m (I) (wherein M is a metal, Q is a halogen selected from Cl, Br, F, or I, z is from 1 to 6, R is selected from alkyl, CO, cyclopentadienyl, amidinato, diazadiene, or amidate, and m is from 0 to 6), the operation of flowing the halide precursor, the operation of purging the halide precursor from the processing chamber, and the substrate with the general formula (II) or general formula (III) TIFF2025081314000003.tif70170 (wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R a , R b, R c , R d , R e , and R f are each independently selected from hydrogen (H), substituted alkyl, or unsubstituted alkyl, and X, Y, X', and Y' are each independently selected from nitrogen (N) and carbon (C)), performing an operation of exposing to an organosilane precursor, and an operation of purging the organosilane precursor from the processing chamber.

Brief Description of the Drawings

[0009] To better understand the above features of the present disclosure, a more specific description of the present disclosure briefly summarized above can be obtained by referring to the embodiments, some of which are shown in the accompanying drawings. However, it should be noted that since the present disclosure may admit other equally effective embodiments, the accompanying drawings show only typical embodiments of the present disclosure and should not be regarded as limiting the scope of the present disclosure.

[0010]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0011] Before describing a plurality of exemplary embodiments of the present disclosure, it should be understood that the present disclosure is not limited to the details of the configurations or process steps shown in the following description. The present disclosure is capable of other embodiments and can be practiced or carried out in various ways.

[0012] As used in this specification and the claims, the term "substrate" refers to the surface or a portion of the surface on which a process acts. One of ordinary skill in the art will understand that references to a substrate may also refer to only a portion of the substrate, unless the context clearly indicates otherwise. Additionally, references to deposition on a substrate may mean both a bare substrate and a substrate on which one or more films or features have been deposited or formed on top.

[0013] As used herein, "substrate" refers to any substrate or any material surface formed on a substrate on which film processing is performed during a manufacturing process. For example, a substrate surface on which processing can be performed can include materials such as silicon, silicon oxide, strained silicon, silicon on insulator (SOI), carbon-doped silicon oxide, amorphous silicon, doped silicon, germanium, gallium arsenide, glass, sapphire, etc., depending on the application, as well as any other materials such as metals, metal nitrides, metal alloys, and other conductive materials. Substrates include, but are not limited to, semiconductor wafers. The substrate may be exposed to a pretreatment process to polish, etch, reduce, oxidize, hydroxylate, anneal, UV cure, electron beam (e-beam) cure, and / or bake the substrate surface. In addition to directly performing film processing on the surface of the substrate itself, in the present disclosure, any of the disclosed film processing steps can also be performed on an underlying layer formed on the substrate as disclosed in more detail below, and the term "substrate surface" is intended to include such underlying layers as the context indicates. Thus, for example, when a film / layer or a partial film / layer is deposited on a substrate surface, the exposed surface of the newly deposited film / layer becomes the substrate surface.

[0014] Terms such as "reactive gas", "precursor", and "reactant" as used in this specification and the claims are used interchangeably to mean a gas containing species that are reactive in an atomic layer deposition process. For example, a first "reactive gas" can simply be adsorbed on the surface of a substrate and utilized for further chemical reaction with a second reactive gas.

[0015] In one or more embodiments, a method for thermal-only atomic layer deposition (ALD) of one or more of a metal film, particularly one or more of titanium and / or aluminum, is described. Some embodiments advantageously provide a method for forming a stable composition having a step coverage of greater than 95%. Some embodiments of the method advantageously provide a work function metal for a gate all around (GAA) architecture.

[0016] Generally, alloys of two electropositive elements are deposited using a metal halide for the first element and an organometallic-based precursor for the second element. The redox reaction between the precursors deposits the alloy film. However, the redox reaction forms carbon residues, which can reduce the ability of the film to exhibit the most effective work function. One or more embodiments advantageously provide an alloy film having a controlled composition and substantially free of impurities such as carbon.

[0017] Titanium (Ti) and aluminum (Al) are both electropositive metals and are extremely difficult to reduce. Some embodiments of the present disclosure provide thermal vapor deposition of pure metal films. Some embodiments advantageously enable composition control of the alloy film by controlling the reactants.

[0018] In one or more embodiments, a thermal atomic layer deposition (ALD) method is provided that includes reduction of a metal halide precursor with an organosilane reductant.

[0019] As used herein, "atomic layer deposition" or "cyclic deposition" refers to the sequential exposure of two or more reactive compounds to deposit a layer of material on a substrate surface. Terms such as "reactive compound", "reactive gas", "reactive species", "precursor", and "process gas" as used herein and in the claims are used interchangeably to mean a substance having species capable of reacting with the substrate surface or a material on the substrate surface in a surface reaction (e.g., chemisorption, oxidation, reduction). The substrate or a portion of the substrate is separately exposed to two or more reactive compounds introduced into the reaction zone of the processing chamber.

[0020] In a time-domain ALD process, the exposure to each reactive compound is separated by a time delay such that each compound can adhere to and / or react on the substrate surface and then be purged from the processing chamber. In a spatial ALD process, different portions of the substrate surface or the material on the substrate surface are simultaneously exposed to two or more reactive compounds such that any given point on the substrate is not substantially simultaneously exposed to two or more reactive compounds. As used herein and in the claims, the term "substantially" in this context means that, as understood by one of ordinary skill in the art, a very small portion of the substrate may be potentially simultaneously exposed to multiple reactive gases due to diffusion, meaning that the simultaneous exposure is not intended.

[0021] In embodiments of time-domain ALD, the exposure to each of the process gases is separated by a time delay / break such that the components of the process gas can adhere to and / or react on the substrate surface. Alternatively, or in combination, in some embodiments, a purge can be performed before and / or after exposing the substrate to the process gas, and an inert gas is used to perform the purge. For example, a first process gas can be provided to the process chamber, followed by a purge with an inert gas. Next, a second process gas can be provided to the process chamber, followed by a purge with an inert gas. In some embodiments, the inert gas is continuously provided to the process chamber, and a first process gas can be dosed or pulsed into the process chamber, followed by a second process gas being dosed or pulsed into the process chamber. In such embodiments, a delay or break can occur between the dosing of the first process gas and the dosing of the second process gas, thereby allowing a continuous flow of inert gas to purge the process chamber between the dosing of the process gases.

[0022] In one aspect of the time-domain ALD process, a first reactive gas (i.e., a first precursor or compound A) is pulsed into the reaction zone, followed by a first time delay. Next, a second precursor or compound B is pulsed into the reaction zone, followed by a second delay. During each time delay, a purge gas, such as argon, is introduced into the processing chamber to purge the reaction zone or otherwise remove any remaining reactive compounds or reaction by-products from the reaction zone. Alternatively, the purge gas may be continuously flowed through the deposition process such that only the purge gas flows during the time delay between pulsed introductions of the reactive compounds. Alternatively, the reactive compounds are pulsed until a desired film or film thickness is formed on the substrate surface. In any case, the ALD process of pulsing compound A, the purge gas, compound B, and the purge gas is one cycle. One cycle can start with compound A or compound B and can continue in each order of that cycle until a film having a predetermined thickness is achieved.

[0023] In one or more embodiments, the purge gas is selected from one or more of argon (Ar), nitrogen (N 2 ), or helium (He). In one or more embodiments, the same purge gas is used to purge the precursor and the reducing agent. In other embodiments, a different purge gas is used to purge the precursor from the processing chamber than the purge gas used to purge the oxidizing agent from the processing chamber.

[0024] In one embodiment of the spatial ALD process, a first reactive gas and a second reactive gas are supplied to the reaction zone simultaneously but are separated by an inert gas curtain and / or a vacuum curtain. The substrate is moved relative to the gas supply device such that any given point on the substrate is exposed to the first reactive gas and the second reactive gas.

[0025] In an embodiment of spatial ALD, the exposure to each of the process gases is performed simultaneously on different portions of the substrate such that a portion of the substrate is exposed to a first reactive gas and a different portion of the substrate is exposed to a second reactive gas (when only two reactive gases are used). The substrate is moved relative to the gas supply system such that each point thereon is continuously exposed to both the first reactive gas and the second reactive gas. In any embodiment of a time-domain ALD or spatial ALD process, the sequence can be repeated until a predetermined layer thickness is formed on the substrate surface.

[0026] As used herein, "pulse introduction" or "dose introduction" is intended to refer to the amount of source gas introduced intermittently or discontinuously into the process chamber. The amount of a particular compound during each pulse introduction can vary over time depending on the duration of the pulse introduction. A particular process gas can include a single compound, or a mixture / combination of two or more compounds, such as the process gases described below.

[0027] The duration of each pulse introduction / dose introduction is variable and can be adjusted, for example, to fit the volume capacity of the processing chamber and the capabilities of the vacuum system coupled thereto. Additionally, the dose introduction time of the process gas can vary depending on the flow rate of the process gas, the temperature of the process gas, the type of control valve, the type of process chamber used, and the adsorption ability of the components of the process gas onto the substrate surface. The dose introduction time can also vary based on the type of layer being formed and the shape dimensions of the device being formed. The dose introduction time must be long enough to substantially adsorb / chemisorb across the entire surface of the substrate and provide an amount of the compound sufficient to form a layer of the process gas components thereon.

[0028] In one or more embodiments, the films described herein can be formed by an atomic layer deposition (ALD) process using a metal halide precursor and an organosilane reducing agent. The atomic layer deposition process of one or more embodiments is a thermal process and does not involve the use of plasma.

[0029] As used herein, "metal film" refers to a film containing a metal. In one or more embodiments, the metal film is substantially free of impurities. In one or more embodiments, the metal film is substantially free of carbon (C), even though the substrate is exposed to a carbon-containing organosilane precursor / reducing agent. As used herein, the expression "substantially free of" means that there is less than about 5% carbon, on an atomic basis, in the metal film, including less than about 4%, less than about 3%, less than about 2%, less than about 1%, and less than about 0.5%.

[0030] In one or more embodiments, the metal film contains, on an atomic basis, a total metal content of greater than about 90%, greater than about 95%, greater than about 96%, greater than about 97%, greater than about 98%, or greater than about 99%. As used herein, the term "total metal amount" refers to the proportion of metal, on an atomic basis, present in the metal film. In one or more embodiments, the metal may be derived from a halide precursor.

[0031] In one or more embodiments, the metal halide precursor comprises a compound having the general formula (I): MQ z R m (I) (wherein M is a metal, Q is a halogen selected from Cl, Br, F, or I, z is from 1 to 6, R is selected from alkyl, CO, cyclopentadienyl, amidinato, diazadiene, or amidate, and m is from 0 to 6).

[0032] In one or more embodiments, metal M is selected from one or more metals from Group III, Group IV, Group V, Group VI, or Group VII of the periodic table, or Sn or Si. In other embodiments, metal M is selected from scandium (Sc), yttrium (Y), lanthanum (La), actinium (Ac), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), rhenium (Re), technetium (Tc), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), tin (Sn), or (silicon) Si. In one or more embodiments, metal M is selected from one or more of Ti, Ta, Zr, La, Hf, Ce, Zn, Cr, Sn, W, or V. In one or more specific embodiments, metal M is selected from one or more of titanium (Ti) and aluminum (Al).

[0033] In one or more embodiments, Q is a halogen selected from Cl, Br, F, or I. In one or more embodiments, z is from 1 to 6, including 1, 2, 3, 4, 5, or 6. In other embodiments, Q is selected from Cl or Br. In a specific embodiment, Q is Cl. In another specific embodiment, Q is Br.

[0034] Unless otherwise indicated, as used herein, "alkyl" or "alk" includes both straight-chain and branched-chain hydrocarbons containing from 1 to 20 carbons in the straight chain, such as, for example, methyl, ethyl, propyl, isopropyl, butyl, t-butyl, isobutyl, pentyl, hexyl, isohexyl, heptyl, 4,4-dimethylpentyl, octyl, 2,2,4-trimethyl-pentyl, nonyl, decyl, undecyl, dodecyl, and various branched-chain isomers thereof. Such groups may optionally contain up to 1 to 4 substituents. In one or more embodiments, R is selected from alkyl, CO, cyclopentadienyl, amidinato, diazadiene, or amidate. In one or more embodiments, R is C 1-6 alkyl. In one or more embodiments, m is from 0 to 6, including 0, 1, 2, 3, 4, 5, or 6.

[0035] In one or more embodiments, the organosilane reducing agent has the formula II or formula III: TIFF2025081314000004.tif93170(wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R a , R b , R c , R d , R e , and R f are independently selected from hydrogen (H), substituted alkyl, or unsubstituted alkyl, and X, Y, X', and Y' are independently selected from nitrogen (N) and carbon (C)).

[0036] As used herein, the term "lower alkyl", "alkyl" or "alk", whether used alone or as part of another group, includes both straight-chain and branched-chain hydrocarbons containing from 1 to 20 carbons in the straight-chain, such as, for example, methyl, ethyl, propyl, isopropyl, butyl, t-butyl, isobutyl, pentyl, hexyl, isohexyl, heptyl, 4,4-dimethylpentyl, octyl, 2,2,4-trimethyl-pentyl, nonyl, decyl, undecyl, dodecyl, and various branched-chain isomers thereof. Such groups may optionally contain up to 1 to 4 substituents. Alkyl may be either substituted or unsubstituted. In a specific embodiment, R a , R b , R c , R d , R e , and R f includes methyl. In some embodiments, each of R a , R b , R c , R d , R e , and R f includes methyl.

[0037] In one or more embodiments, the organosilane reducing agent is selected from bis(trimethylsilyl)cyclohexadiene, bis(trimethylsilyl)diazacyclohexadiene, bis(trimethylsilyl)azacyclohexadiene, bis(trimethylsilyl)dihydropyridine, 3,6-bis(trimethylsilyl)-1,4-cyclohexadiene, 1-methyl-3,6-bis(trimethylsilyl)-1,4-cyclohexadiene, and 1,4-bis-(trimethylsilyl)-1,4-diaza-2,5-cyclohexadiene.

[0038] Referring to FIG. 1, one or more embodiments of the present disclosure are directed to a method 10 of depositing a thin film. The method shown in FIG. 1 represents a thermal atomic layer deposition (ALD) process in which a substrate or substrate surface is continuously exposed to a reactive gas such that the gas phase reaction of the reactive gas is prevented or minimized.

[0039] In some embodiments, method 10 includes an optional pretreatment operation 20. The pretreatment can be any suitable pretreatment known to those skilled in the art. Suitable pretreatments include, but are not limited to, preheating, cleaning, dipping, natural oxide removal, or deposition of an adhesion layer (e.g., titanium nitride (TiN)). In one or more embodiments, an adhesion layer such as titanium nitride is deposited in the pretreatment operation 20.

[0040] Referring to FIG. 1, method 10 includes a deposition cycle 70. In the deposition operation 30, a process of depositing a metal-containing film on a substrate (or a substrate surface) is performed. In operation 30, the substrate (or substrate surface) is exposed to a halide precursor containing a compound having the general formula (I): MQ z R m (I) (wherein M is a metal, Q is a halogen selected from Cl, Br, F or I, z is from 1 to 6, R is selected from alkyl, CO, cyclopentadienyl, amidinato, diazadiene, or amidate, and m is from 0 to 6). In one or more specific embodiments, the halide precursor contains titanium tetrachloride (TiCl 4 ), and titanium species are formed on the substrate surface. In other embodiments, the halide precursor contains aluminum chloride (AlCl 3 ), and aluminum species are formed on the substrate surface.

[0041] In one or more embodiments, the halide precursor-containing process gas can be provided in one or more pulsed introductions or continuously. The flow rate of the halide precursor-containing process gas can be any suitable flow rate including, but not limited to, a flow rate in the range of about 1 to about 5000 sccm, or in the range of about 2 to about 4000 sccm, or in the range of about 3 to about 3000 sccm, or in the range of about 5 to about 2000 sccm. The halide precursor of Formula I can be provided at any suitable pressure including, but not limited to, a pressure in the range of about 5 mTorr to about 40 Torr, or in the range of about 100 mTorr to about 40 Torr, or in the range of about 5 Torr to about 40 Torr, or in the range of about 50 mTorr to about 2000 mTorr, or in the range of about 100 mTorr to about 1000 mTorr, or in the range of about 200 mTorr to about 500 mTorr.

[0042] In one or more embodiments, the period during which the substrate is exposed to the halide precursor-containing process gas can be any suitable amount of time necessary to allow the precursor to form a suitable nucleation layer on the conductive substrate surface. For example, the process gas can be flowed into the process chamber over a period of about 0.1 second to about 90 seconds. In some time-domain ALD processes, the substrate surface is exposed to the halide precursor-containing process gas for a time in the range of about 0.1 second to about 90 seconds, or in the range of about 0.5 second to about 60 seconds, or in the range of about 1 second to about 30 seconds, or in the range of about 2 seconds to about 25 seconds, or in the range of about 3 seconds to about 20 seconds, or in the range of about 4 seconds to about 15 seconds, or in the range of about 5 seconds to about 10 seconds.

[0043] In some embodiments, an inert carrier gas may be additionally provided to the process chamber simultaneously with the halide precursor-containing process gas. The carrier gas may be mixed with the halide precursor-containing process gas (e.g., as a dilution gas), separated, or may be pulsed or have a constant flow rate. In some embodiments, the carrier gas is introduced into the processing chamber at a constant flow rate in the range of about 1 to about 10,000 sccm. The carrier gas may be any inert gas such as, for example, argon (Ar), nitrogen (N), helium (He), neon (Ne), or combinations thereof. In one or more specific embodiments, the halide precursor-containing process gas is mixed with argon before being introduced into the process chamber.

[0044] In one or more embodiments, during deposition, the temperature of the substrate can be controlled, for example, by setting the temperature of the substrate support. In some embodiments, the substrate is maintained at a temperature in the range of about 100°C to about 500°C, including temperatures of about 100°C, about 150°C, about 200°C, about 250°C, about 300°C, about 350°C, about 400°C, about 450°C, and about 500°C.

[0045] In one or more embodiments, in operation 40, the halide precursor is then purged from the process chamber. The purge can be achieved using any suitable gas that is not reactive with the substrate, the film on the substrate, and / or the process chamber walls. Suitable purge gases include, but are not limited to, nitrogen (N 2 ), helium (He), and argon (Ar). The purge gas can be used to purge the halide precursor and / or the organosilane reactant from the process chamber. In some embodiments, the same purge gas is used for each purge operation. In other embodiments, different purge gases are used for different purge operations.

[0046] In one or more embodiments, in operation 50, at least a portion of the substrate surface is exposed to an organosilane reactant to deposit a metal film. The organosilane reactant has the general formula (II) or general formula (III) TIFF2025081314000005.tif92170(wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R a , R b , R c , R d , R e , and R f are independently selected from hydrogen (H), substituted alkyl, or unsubstituted alkyl, and X, Y, X', and Y' are independently selected from nitrogen (N) and carbon (C)).

[0047] In one or more specific embodiments, the organosilane precursor reacts with metal species on the substrate surface to form a metal film. For example, in an embodiment where the halide precursor includes titanium tetrachloride (TiCl 4 ), the organosilane precursor reduces the titanium species to form a titanium film.

[0048] In one or more embodiments, in operation 60, the organosilane reactant is then purged from the processing chamber. In one or more embodiments, the metal film is deposited on the substrate surface. In one or more embodiments, the metal film is substantially free of carbon.

[0049] In decision 80, the thickness of the deposited film or the number of cycles of the halide precursor and the organosilane precursor is considered. If the deposited film has reached a predetermined thickness or a predetermined number of process cycles have been performed, method 10 proceeds to post-processing operation 90. If the thickness of the deposited film or the number of process cycles has not reached a predetermined threshold, method 10 returns to deposition operation 70, exposes the substrate surface to the halide precursor again in operation 30, and continues.

[0050] In one or more embodiments, deposition cycle 70 is repeated. In operation 30, the halide precursor of Formula I comprises a precursor different from that in the first deposition cycle. For example, in one or more embodiments, the halide precursor comprises aluminum chloride (AlCl 3 ) to form aluminum species, which are then reduced by an organosilane precursor. In some embodiments, the precursor may not be changed every cycle. In some embodiments, for example, one precursor can be used for 5 cycles and then another precursor can be used for 3 cycles.

[0051] Optional post-treatment operation 90 can be, for example, a process for modifying film properties (e.g., annealing or densification), or a further film deposition process for growing an additional film (e.g., an additional ALD or CVD process). In some embodiments, post-treatment operation 90 can be a process for modifying the properties of the deposited film. In some embodiments, post-treatment operation 90 includes annealing the as-deposited film. In some embodiments, the annealing is performed at a temperature in the range of about 300 °C, 400 °C, 500 °C, 600 °C, 700 °C, 800 °C, 900 °C or 1000 °C. The annealing environment in some embodiments includes one or more of an inert gas (e.g., molecular nitrogen (N 2 ), argon (Ar)), or a reducing gas (e.g., molecular hydrogen (H 2 ) or ammonia (NH 3 )) or, without limitation, an oxidizing agent such as oxygen (O 2 ), ozone (O 3 ) or peroxide. The annealing can be carried out over any suitable length of time. In some embodiments, the film is annealed for a predetermined time in the range of about 15 seconds to about 90 minutes, or in the range of about 1 minute to about 60 minutes. In some embodiments, annealing the as-deposited film increases the density of the film, decreases the resistance, and / or increases the purity of the film.

[0052] In one or more embodiments, method 10 can be performed at any suitable temperature, e.g., depending on the halide precursor, organosilane reducing agent, or the thermal budget of the device. In some embodiments, the exposure to the halide precursor (operation 30) and the exposure to the organosilane reducing agent (operation 50) are performed at the same temperature. In some embodiments, the substrate is maintained at a temperature in the range of about 200°C to about 500°C, or in the range of about 350°C to about 500°C.

[0053] In one or more embodiments, a titanium aluminum (TiAl) film, which is a metal film, has a carbon content of about 5% or less on an atomic basis.

[0054] In one or more embodiments, a metal film containing about 5% or less carbon on an atomic basis may be subjected to further processing to form a metal carbide film. In such embodiments, the metal portion of the carbide film, e.g., titanium aluminum (TiAl), contains less than about 5% carbon impurities.

[0055] In one or more embodiments, the method is used to deposit pure thermal titanium (Ti) metal and (aluminum) Al metal, which can be further processed to obtain a TiAl film. The deposited film may have a certain degree of C incorporation and can form TiAlC.

[0056] One or more embodiments of the present disclosure are directed to a metal oxide stack that is part of a gate stack in a metal oxide semiconductor (MOS). Referring to FIG. 2, the metal oxide stack 100 includes a high-k dielectric layer 104 on a substrate 102 and a titanium nitride layer 106 on the high-k dielectric layer 104. The embodiment shown in FIG. 2 has a separate high-k dielectric layer 104 on the substrate 102. However, those skilled in the art will recognize that the high-k dielectric layer 104 can be the substrate 102 or a part of the substrate 102. For example, the high-k dielectric layer 104 can be formed on the substrate 102 to form the metal oxide stack 100.

[0057] In one or more embodiments, the metal oxide stack 100 is formed on a substrate 102 that can be of any suitable material or shape. In the illustrated embodiment, the substrate 102 is a flat surface and the metal oxide stack 100 is represented by a rectangular box stacked vertically. However, those skilled in the art will understand that the substrate 102 can have one or more features (i.e., trenches or vias), and the metal oxide stack 100 can be formed to conform to the shape of the surface of the substrate 102.

[0058] In one or more embodiments, a work function layer 108 is formed on the titanium nitride layer 106. In one or more embodiments, the work function layer 108 includes a carbon-free metal film having less than about 5% carbon on an atomic basis. The metal film is prepared by a method of one or more embodiments. The metal film exposes at least a portion of the substrate 102 to a halide precursor containing a compound having the general formula (I): MQ z R m (I) (wherein M is a metal, Q is a halogen selected from Cl, Br, F or I, z is from 1 to 6, R is selected from alkyl, CO, cyclopentadienyl, amidinato, diazadiene or amidate, and m is from 0 to 6), and exposes at least a portion of the substrate 102 to a compound having the general formula (II) or general formula (III) TIFF2025081314000006.tif92170 (wherein R 1 、R 2 、R 3 、R 4 、R 5 、R 6 、R 7 、R 8 、R a 、R b 、R c 、R d 、R e 、and R fis formed by exposing, independently, to an organosilane reducing agent comprising a compound selected from hydrogen (H), substituted alkyl or unsubstituted alkyl, and X, Y, X', and Y' are independently selected from nitrogen (N) and carbon (C)), and a metal film substantially free of carbon can be deposited on the substrate 102 as the work function layer 108.

[0059] In some embodiments, exposing the substrate surface to the halide precursor and the organosilane reactant is performed continuously. For example, an ALD-type process is performed such that the substrate surface (or a portion thereof) is continuously or substantially continuously exposed to the halide precursor and the organosilane reactant. In some embodiments, exposing the substrate surface to the halide precursor and the organosilane reactant is performed simultaneously. For example, there is a chemical vapor deposition (CVD)-type process in which both the halide precursor and the organosilane reactant are simultaneously introduced into the processing chamber to enable a gas-phase reaction between the precursor and the reactant.

[0060] According to one or more embodiments, the substrate is subjected to processing before and / or after the formation of the layer. This processing can be performed in the same chamber or in one or more separate processing chambers. In some embodiments, the substrate is moved from a first chamber to a separate second chamber for further processing. The substrate can be moved directly from the first chamber to a separate processing chamber, or the substrate can be moved from the first chamber to one or more transfer chambers and then to a separate processing chamber. Thus, the processing apparatus can include a plurality of chambers in communication with a transfer station. This type of apparatus is sometimes also referred to as a "cluster tool" or "clustered system", etc.

[0061] Typically, a cluster tool is a modular system that includes multiple chambers that perform various functions including substrate centering and orientation, degassing, annealing, deposition, and / or etching. According to one or more embodiments, a cluster tool includes at least a first chamber and a central transfer chamber. The central transfer chamber can house a robot capable of reciprocally transporting substrates between and among processing chambers and load lock chambers. The transfer chamber is generally maintained in a vacuum state and provides an intermediate stage for reciprocally transporting substrates from one chamber to another and / or to a load lock chamber positioned at the front end of the cluster tool. Two well-known cluster tools that can be adapted for the present disclosure are Centura® and Endura®, both available from Applied Materials, Inc. (Santa Clara, Calif.). However, the exact arrangement and combination of chambers can be varied for the purpose of performing specific portions of the processes described herein. Other processing chambers that can be used include, but are not limited to, thermal processes such as cyclic layer deposition (CLD), atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), etching, pre-cleaning, chemical cleaning, rapid thermal processing (RTP), plasma nitridation, degassing, orientation, hydroxylation, and other substrate processes. By performing processes in the chambers on the cluster tool, surface contamination of the substrate by impurities in the atmosphere can be avoided without oxidizing prior to depositing the next film.

[0062] According to one or more embodiments, the substrate is continuously under vacuum or “load lock” conditions and is not exposed to ambient air when moving from one chamber to the next. Thus, the transfer chamber is under vacuum and is “pumped down” under vacuum pressure. An inert gas may be present in the processing chamber or the transfer chamber. In some embodiments, after forming a layer on the surface of the substrate, an inert gas is used as a purge gas to remove some or all of the reactants. According to one or more embodiments, a purge gas is injected at the outlet of the deposition chamber to prevent reactants from moving from the deposition chamber to the transfer chamber and / or additional processing chambers. In this way, a flow of inert gas forms a curtain at the outlet of the chamber.

[0063] During processing, the substrate can be heated or cooled. Such heating or cooling can be accomplished by any suitable means including, but not limited to, changing the temperature of the substrate support (e.g., susceptor) and flowing heated or cooled gas over the substrate surface. In some embodiments, the substrate support includes a heater / cooler that can be controlled to conductively change the substrate temperature. In one or more embodiments, the gas (reactive or inert) being used is heated or cooled to locally change the substrate temperature. In some embodiments, the heater / cooler is positioned within the chamber adjacent to the substrate surface to change the substrate temperature by convection.

[0064] The substrate may also be stationary or rotated during processing. The rotating substrate can be rotated continuously or intermittently. For example, the substrate may be rotated throughout the process or rotated incrementally between exposures to different reactive or purge gases. Rotating the substrate (continuously or intermittently) during processing can help to produce more uniform deposition or etching, for example, by minimizing the effects of local variability in the geometry of the gas flow.

[0065] In the context of the materials and methods described in this specification (especially in the context of the claims), the use of "one" (including "a" and "an"), "the", and similar indicators should be construed to include both the singular and the plural, unless otherwise indicated in this specification or clearly inconsistent with the context. The recitation of a range of values in this specification is intended only as a shorthand for referring individually to each separate value within the range, and each separate value is incorporated into this specification as if it were individually recited herein. All methods described in this specification can be performed in any suitable order, unless otherwise indicated in this specification or clearly inconsistent with the context. The use of any and all examples, or exemplary language (e.g., "such as", "etc.") provided herein is intended only to better illustrate the materials and methods and is not limiting of the scope unless otherwise claimed. No language in the specification, and no element that is not claimed, should be construed as essential to the practice of the disclosed materials and methods.

[0066] References throughout this specification to "one embodiment", "some embodiments", "one or more embodiments", or "an embodiment" mean that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Thus, the appearances of the phrases "in one or more embodiments", "in some embodiments", "in one embodiment", or "in an embodiment" in various places throughout this specification are not necessarily referring to the same embodiment of the present disclosure. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments.

[0067] Although the disclosure of this specification has been described with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the present disclosure. It will be apparent to those skilled in the art that various modifications and variations can be made to the methods and apparatuses of the present disclosure without departing from the essence and scope of the present disclosure. Therefore, the present disclosure is intended to cover modifications and variations that are within the scope of the claims and their equivalents.

Claims

1. 1. A method of depositing a film, comprising: At least a portion of the surface of the substrate is treated with a compound represented by general formula (I) MQ ｚ R ｍ (I) wherein M is a metal, Q is a halogen selected from Cl, Br, F or I, z is 1 to 6, R is selected from alkyl, CO, cyclopentadienyl, amidinate, diazadiene, or amidate, and m is 0 to 6; At least a portion of the substrate surface is represented by general formula (II) or general formula (III) (In the formula, R １ , R ２ , R ３ , R ４ , R ５ , R ６ , R ７ , R ８ , R ａ , R ｂ , R ｃ , R ｄ , R ｅ , and R ｆ are independently selected from hydrogen (H), substituted alkyl or unsubstituted alkyl, and X, Y, X', and Y' are independently selected from nitrogen (N) and carbon (C); depositing a substantially carbon-free metal film on a surface of the substrate.

2. 2. The method of claim 1, wherein M is selected from one or more of scandium (Sc), yttrium (Y), lanthanum (La), actinium (Ac), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), rhenium (Re), technetium (Tc), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), tin (Sn), and silicon (Si).

3. The method of claim 2 , wherein M is selected from one or more of titanium (Ti) and aluminum (Al).

4. The method of claim 1 , wherein Q is Cl or Br.

5. The method of claim 1 , wherein Q is Cl.

6. R ａ , R ｂ , R ｃ , R ｄ , R ｅ , and R ｆ The method of claim 1 , wherein at least one of comprises methyl.

7. The method of claim 1 , wherein exposing the substrate surface to the halide precursor and the organosilane reactant is performed sequentially.

8. The method of claim 1 , wherein exposing the substrate surface to the first halide precursor and the organosilane reactant occurs simultaneously.

9. 2. The method of claim 1, wherein the organosilane reactant is selected from one or more of bis(trimethylsilyl)cyclohexadiene, bis(trimethylsilyl)diaza-cyclohexadiene, bis(trimethylsilyl)-aza-cyclohexadiene, bis(trimethylsilyl)-dihydro-bipyridine, 3,6-bis(trimethylsilyl)-1,4-cyclohexadiene, 1-methyl-3,6-bis(trimethylsilyl)-1,4-cyclohexadiene, and 1,4-bis-(trimethylsilyl)-1,4-diaza-2,5-cyclohexadiene.

10. The method of claim 1 further comprising repeating the method to provide a metal film comprising two or more metals M.

11. The method of claim 1 , wherein the metal film comprises a titanium aluminum (TiAl) film.

12. The method of claim 1 , wherein the substrate is in a processing chamber.

13. 13. The method of claim 12, further comprising purging the halide precursor from the process chamber prior to exposing the substrate to the organosilane reactant.

14. The method of claim 13 further comprising purging the organosilane reactant from the processing chamber.

15. Purging the process chamber includes flowing a purge gas into the process chamber, the purge gas being nitrogen (N ２ 15. The method of claim 14, wherein the oxygen is selected from one or more of: helium (He), and argon (Ar).

16. A high-k dielectric layer on the substrate; a first titanium nitride layer on said high-k dielectric layer; a work function layer on the first titanium nitride layer; and a second titanium nitride layer on the work function layer; wherein the work function layer comprises a metal film that is substantially free of carbon.

17. 17. The gate stack of claim 16, wherein the metal film comprises one or more metals selected from scandium (Sc), yttrium (Y), lanthanum (La), actinium (Ac), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), rhenium (Re), technetium (Tc), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), tin (Sn), and silicon (Si).

18. 20. The gate stack of claim 17, wherein the metal film comprises one or more of titanium (Ti) and aluminum (Al).

19. 20. The gate stack of claim 18, wherein the work function layer comprises titanium aluminum carbide (TiAlC).

20. 1. A non-transitory computer readable medium comprising instructions that, when executed by a controller of a processing chamber, cause the processing chamber to: Flowing a halide precursor into a process volume of the process chamber having a substrate, the halide precursor having a general formula (I): MQ ｚ R ｍ (I) flowing a halide precursor having the formula: wherein M is a metal, Q is a halogen selected from Cl, Br, F or I, z is 1 to 6, R is selected from alkyl, CO, cyclopentadienyl, amidinate, diazadiene, or amidate, and m is 0 to 6; purging the halide precursor from the process chamber; The substrate is a compound represented by general formula (II) or general formula (III) (In the formula, R １ , R ２ , Ｒ 3. R ４ , R ５ , R ６ , R ７ , R ８ , R ａ , R ｂ , R ｃ , R ｄ , R ｅ , and R ｆ are independently selected from hydrogen (H), substituted or unsubstituted alkyl, and X, Y, X', and Y' are independently selected from nitrogen (N) and carbon (C); purging the organosilane precursor from the processing chamber; A computer-readable medium for implementing the above.

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