Conformal molybdenum deposition

Abstract

[0003] Embodiments of the present disclosure provide conformally deposited molybdenum films having reduced resistivity, and methods for forming the same. The methods include forming a nucleation layer directly on a dielectric layer on a substrate surface by exposing the substrate surface to a molybdenum-containing precursor and a nucleation reactant, and conformally depositing a molybdenum film on the nucleation layer. Another aspect of the present disclosure relates to a method that is part of a gap-fill process, including forming a nucleation layer directly on a dielectric region within one or more high-aspect-ratio gap features, including vertical and / or horizontal gap features, and conformally depositing a molybdenum film on the nucleation layer to fill the feature.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE Embodiments of the present disclosure relate to metal film deposition. More particularly, embodiments of the present disclosure are directed to conformal molybdenum deposition. [Background technology]

[0002] As circuit integration increases, the need for improved uniformity and process control over layer thickness increases. As a result, various techniques have been developed to deposit layers onto substrates in a cost-effective manner while maintaining control over the layer's properties. Chemical vapor deposition (CVD) is one of the most common deposition processes used to deposit layers onto substrates.

[0003] One variation of CVD that exhibits excellent step coverage is cyclic deposition or atomic layer deposition (ALD). ALD employs a chemisorption technique that delivers precursor molecules to a substrate surface in successive cycles. An ALD cycle involves exposing the substrate surface to a first precursor, a purge gas, a second precursor, and a purge gas. The first precursor and the second precursor react to form a product compound as a film on the substrate surface. The ALD cycle is repeated to form a layer to a desired thickness.

[0004] The increasing complexity of advanced microelectronic devices places stringent demands on currently used deposition techniques. Molybdenum and molybdenum-based films possess attractive material and conductive properties. These films have been proposed and tested for applications ranging from the front-end to the back-end of semiconductor and microelectronic devices.

[0005] Without being bound by any particular theory or principle, it is believed that molybdenum cannot be deposited and grown directly on a dielectric surface, but can be deposited and grown on a metal surface.

[0006] Molybdenum films can be used as low-resistance electrical connections in the form of current-carrying vertical and / or horizontal interconnects, as vias between adjacent metal layers, and as contacts between the first metal layer and devices on the substrate. For example, in both blanket and gap-fill applications, a liner film (e.g., a TiN liner film) is typically deposited on the dielectric surface to achieve repeatable molybdenum deposition. In gap-fill applications, TiN is deposited within the gap to achieve both low resistance and conformal deposition. Conformal deposition is often required to uniformly deposit metal films over three-dimensional structures containing high-aspect-ratio features.

[0007] There is a continuing need for improved metal liners or layers to provide lower resistivity molybdenum films. Therefore, improved materials and methods for depositing metal films on dielectric surfaces are needed to provide conformal molybdenum deposits with improved film properties. Summary of the Invention

[0008] One or more embodiments of the present disclosure are directed to a deposition method that includes forming a nucleation layer directly on a dielectric layer on a substrate surface by exposing the substrate surface to a molybdenum-containing precursor and a nucleation reactant; and conformally depositing a molybdenum film on the nucleation layer.

[0009] An additional embodiment of the present disclosure is directed to a method for filling a feature formed on a substrate surface. The method includes forming a nucleation layer directly on a dielectric region within the feature by exposing the dielectric to a molybdenum-containing precursor and a nucleation reactant. The feature includes at least one surface defining a via. The via has a bottom and two sidewalls comprising a dielectric. The method further includes conformally depositing a molybdenum film on the nucleation layer to fill the feature, the conformally deposited molybdenum film being substantially free of seams and voids.

[0010] A further embodiment of the present disclosure is directed to a non-transitory computer-readable medium comprising instructions that, when executed by a controller of a processing chamber, cause the processing chamber to form a nucleation layer directly on a dielectric layer on a substrate surface by exposing the substrate surface to a molybdenum-containing precursor and a nucleation reactant; and conformally deposit a molybdenum film on the nucleation layer.

[0011] So that the above features of the present disclosure can be understood in detail, a more particular description of the present disclosure, briefly summarized above, can be had by reference to embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings illustrate only typical embodiments of the present disclosure and therefore should not be considered as limiting its scope, since the present disclosure may admit of other equally effective embodiments. The embodiments described herein are shown by way of example and not by way of limitation to the figures of the accompanying drawings in which like references indicate like elements. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a process flow diagram of a deposition method according to one or more embodiments. [Figure 2A] 1 is a schematic cross-sectional view of a dielectric layer on a substrate surface according to one or more embodiments. [Figure 2B] 2B is a schematic cross-sectional view of a nucleation layer on a dielectric layer on the substrate surface shown in FIG. 2A in accordance with one or more embodiments. [Figure 2C] 2C is a schematic cross-sectional view of a metal film on a nucleation layer shown in FIG. 2B in accordance with one or more embodiments. [Figure 3A] 1 is a schematic cross-sectional view of a feature on a substrate according to one or more embodiments. [Figure 3B] 3B is a schematic cross-sectional view of a nucleation layer on a dielectric region of a feature on a substrate shown in FIG. 3A in accordance with one or more embodiments. [Figure 3C] 3C is a schematic cross-sectional view of a metal film conformally deposited on the nucleation layer shown in FIG. 3B in accordance with one or more embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0013] Before describing several example embodiments of the present disclosure, it is to be understood that the present disclosure is not limited to the details of construction or process steps set forth in the following description. The present disclosure is capable of other embodiments and of being practiced or carried out in various ways.

[0014] As used herein, the term "about" means approximately or near, and in the context of a stated numerical value or range, refers to a variation of no more than ±15% of the numerical value. For example, values that vary by ±14%, ±10%, ±5%, ±2%, or ±1% would meet the definition of about.

[0015] As used herein and in the appended claims, the terms "substrate" or "wafer" refer to a surface or portion of a surface on which processing occurs. Those skilled in the art will also understand that reference to a substrate may refer to only a portion of a substrate, unless the context clearly indicates otherwise. Furthermore, when reference is made to deposition on a substrate, it may refer to both a bare substrate and a substrate with one or more films or features deposited or formed thereon.

[0016] As used herein, the term "substrate" refers to any substrate or material surface formed on a substrate on which a film processing operation is performed during a manufacturing process. For example, substrate surfaces on which processing may be performed include materials such as silicon, silicon oxide, strained silicon, silicon-on-insulator (SOI), carbon-doped silicon oxide, amorphous silicon, doped silicon, germanium, gallium arsenide, and any other materials such as metals, metal nitrides, metal alloys, and other conductive materials, depending on the application. In some embodiments, the substrate comprises one or more of titanium nitride (TiN), titanium silicide (TiSi), tungsten-titanium silicide alloy, purified silicon (Si), boron-doped silicon germanium (SiGeB), purified silicon phosphide (SiP), titanium aluminum (TiAl), ruthenium (Ru), tungsten (W), and molybdenum (Mo). Substrates include, but are not limited to, semiconductor wafers.

[0017] The substrate may be exposed to a pretreatment process to polish, etch, reduce, oxidize, hydroxylate, anneal, and / or bake the substrate surface. In addition to directly treating the surface of the substrate itself, in the present disclosure, any of the disclosed film treatment steps may 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 an underlying layer, as the context indicates. Thus, for example, if a film / layer or partial film / layer is being deposited on a substrate surface, the exposed surface of the newly deposited film / layer would be the substrate surface.

[0018] As used herein, the term "substrate surface" refers to any substrate surface upon which a layer may be formed. A substrate surface may have one or more features formed therein, one or more layers formed thereon, and combinations thereof. The shape of a feature may be any suitable shape, including, but not limited to, a peak, a trench, and a cylindrical via. As used in this context, the term "feature" refers to any intentional surface irregularity. Suitable examples of features include, but are not limited to, a trench having a top, two sidewalls, and a bottom; a peak having a top and two sidewalls extending upward from the surface; and a via having sidewalls extending downward from the surface and a bottom. In some embodiments, the bottom of the via includes an open bottom defined or bounded by an underlying material, such as a dielectric material, which may also define two sidewalls; or the bottom underlying material may be a conductor, such as a metal (e.g., copper), which may be the same as or different from the sidewall material.

[0019] The term "preferentially," as used herein and in the appended claims, refers to a process that acts with greater effectiveness on a first surface than on another, second surface. Such a process would be described as acting "preferentially" on the first surface over the second surface. As used in this regard, the term "over" does not refer to the physical orientation of one surface over another, but rather to the relationship of the thermodynamic or kinetic properties of a chemical reaction relative to one surface and the other.

[0020] The term "on" indicates that there is direct contact between elements. The term "directly on" indicates that there is direct contact between elements, with no intervening elements.

[0021] As used herein and in the appended claims, the terms "precursor," "reactant," "reactive gas," and the like are used interchangeably to refer to any gaseous species capable of reacting with the substrate surface.

[0022] As used herein, "atomic layer deposition" or "cyclic deposition" refers to the deposition of layers of material on a substrate surface by sequential exposure to two or more reactive compounds. A substrate or a portion of a substrate is separately exposed to two or more reactive compounds introduced into a reaction zone of a processing chamber. In a time-domain ALD process, exposure to each reactive compound is separated by a time delay, allowing each compound to adhere to and / or react with the substrate surface and then be purged from the processing chamber. These reactive compounds are said to be sequentially exposed to the substrate. In a spatial ALD process, different portions of the substrate surface or materials on the substrate surface are simultaneously exposed to two or more reactive compounds such that any given point on the substrate is not substantially exposed to more than one reactive compound at the same time. As used herein and in the appended claims, the term "substantially" in this context means that, as will be understood by those skilled in the art, small portions of the substrate may be exposed to multiple reactive gases simultaneously due to diffusion, but simultaneous exposure is not intended.

[0023] In one aspect of a 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. Then, 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 residual reactive compound or reaction by-products from the reaction zone. Alternatively, the purge gas may flow continuously throughout the deposition process, with only the purge gas flowing during the time delay between pulses of reactive compound. Alternatively, the reactive compound is pulsed until a desired film or film thickness is formed on the substrate surface. In either scenario, the ALD process of pulsing compound A, purge gas, compound B, and purge gas is one cycle. The cycle can begin with either compound A or compound B, and the respective sequence of cycles can be continued until a film of the desired thickness is achieved.

[0024] In one embodiment of a spatial ALD process, a first reactive gas and a second reactive gas (e.g., nitrogen gas) are simultaneously delivered to a reaction zone but separated by an inert gas curtain and / or a vacuum curtain, and the substrate is moved relative to the gas delivery system so that any given point on the substrate is exposed to both the first reactive gas and the second reactive gas.

[0025] Embodiments of the present disclosure advantageously provide a method for improving the resistance of a blanket molybdenum film deposited on an underlying molybdenum layer formed by the methods described in this disclosure.

[0026] Resistivity is an intrinsic property of a material and is a measure of the material's resistance to the transfer of electrical charges through it. The resistivity of a material affects the electrical operation of integrated circuits. Low-resistivity molybdenum films minimize power loss and overheating in integrated circuit designs. Because the resistivity of the nucleation layer is generally greater than that of the bulk material, the thickness of the nucleation layer must be minimized to keep the total resistance as low as possible. Meanwhile, the molybdenum nucleation layer must be thick enough to completely cover the underlying substrate to support high-quality bulk deposition. Obtaining a thin nucleation layer becomes even more important for thin features with narrow widths and / or high aspect ratios.

[0027] In addition to providing low-resistivity molybdenum-containing films, the methods described herein provide films with good uniformity and adhesion to underlying materials. One or more embodiments provide a method for depositing a molybdenum nucleation layer directly onto a dielectric surface. The inventors surprisingly discovered that a unique combination of a molybdenum-containing precursor and a nucleation reactant enables the deposition of molybdenum onto a dielectric surface. Further embodiments advantageously provide a method for reducing stack resistance in bottom-up gapfill of vias while improving the properties of the molybdenum film.

[0028] Embodiments of the present disclosure are illustrated by figures that show devices (e.g., transistors) and processes for forming transistors in accordance with one or more embodiments of the present disclosure. The processes shown are merely exemplary possible uses of the disclosed processes, and one skilled in the art will recognize that the disclosed processes are not limited to the applications shown.

[0029] FIG. 1 illustrates a process flow diagram of a deposition method 100 according to one or more embodiments of the present disclosure. The deposition method 100 includes, in operation 110, forming a nucleation layer directly on a dielectric surface, for example, a dielectric layer on a substrate or a dielectric region of a substrate. In some embodiments, forming a nucleation layer directly on the dielectric surface in operation 110 includes exposing the substrate surface to a molybdenum-containing precursor and a nucleation reactant. Generally, a nucleation layer is a thin conformal layer that serves to facilitate the subsequent formation of a bulk material. As used herein, the term "nucleation layer" refers to a layer deposited on a dielectric surface that enables the formation of a bulk material (e.g., a molybdenum-containing film) thereon. In some embodiments, the nucleation reactant is different from the molybdenum film reactant.

[0030] In some embodiments, forming the nucleation layer in operation 110 includes one or more of atomic layer deposition (ALD), co-flow of a molybdenum-containing precursor and a nucleation reactant, chemical vapor deposition (CVD), or pulsed chemical vapor deposition (pCVD).

[0031] In some embodiments, forming the nucleation layer in operation 110 comprises atomic layer deposition (ALD), which includes one or more cycles of exposing the substrate surface to a first precursor (e.g., a molybdenum-containing precursor), a purge gas, a second precursor (e.g., a nucleation reactant), and a purge gas.

[0032] In some embodiments, forming the nucleation layer in operation 110 comprises a spatial ALD process in which a first reactive gas (e.g., a molybdenum-containing precursor) and a second reactive gas (e.g., a nucleation reactant) are simultaneously delivered to a reaction zone but separated by an inert gas curtain and / or a vacuum curtain. In some embodiments, forming the nucleation layer in operation 110 comprises co-flowing a molybdenum-containing precursor and a nucleation reactant. In some embodiments, forming the nucleation layer in operation 110 comprises chemical vapor deposition (CVD). In some embodiments, forming the nucleation layer in operation 110 comprises pulsed chemical vapor deposition (pCVD) in which one or both of the reactants are pulsed into a chamber.

[0033] In some embodiments, the molybdenum-containing precursor comprises one or more of molybdenum pentachloride (MoCl5), molybdenum dioxide dichloride (MoO2Cl2), molybdenum oxytetrachloride (MoOCl4), or molybdenum hexafluoride (MoF6).

[0034] In some embodiments, the nucleation reactant comprises one or more of silane (SiH4), disilane (Si2H6), or diborane (B2H6).

[0035] In one or more embodiments, forming a nucleation layer directly on the dielectric surface in operation 110 is performed at a temperature in the range of 300°C to 700°C, e.g., 300°C to 650°C, 300°C to 600°C, 300°C to 550°C, or 300°C to 500°C, and at a pressure in the range of 1 Torr to 300 Torr, e.g., 10 Torr to 250 Torr, or 10 Torr to 200 Torr.

[0036] The deposition method 100 includes conformally depositing a molybdenum film on the nucleation layer in operation 120. In some embodiments, conformally depositing the molybdenum film in operation 120 includes exposing the nucleation layer to a molybdenum film reactant different from the molybdenum-containing precursor and the nucleation reactant. In some embodiments, the molybdenum-containing precursor includes one or more of molybdenum pentachloride (MoCl), molybdenum dioxide dichloride (MoOCl), molybdenum oxytetrachloride (MoOCl), or molybdenum hexafluoride (MoF). In some embodiments, the molybdenum film reactant includes hydrogen (H).

[0037] In one or more embodiments, conformally depositing the molybdenum film in operation 120 includes one or more of atomic layer deposition (ALD), co-flow of a molybdenum-containing precursor and hydrogen (H), chemical vapor deposition (CVD), or pulsed chemical vapor deposition (pCVD). In some embodiments, conformally depositing the molybdenum film in operation 120 includes atomic layer deposition (ALD) including one or more cycles of exposing the substrate surface to a first precursor (e.g., a molybdenum-containing precursor), a purge gas, a second precursor (e.g., a molybdenum film reactant), and a purge gas.

[0038] In some embodiments, conformally depositing a molybdenum film in process 120 comprises a spatial ALD process in which a first reactive gas (e.g., a molybdenum-containing precursor) and a second reactive gas (e.g., a molybdenum film reactant) are simultaneously delivered to a reaction zone but separated by an inert gas curtain and / or a vacuum curtain. In some embodiments, conformally depositing a molybdenum film in process 120 comprises co-flowing a molybdenum-containing precursor with hydrogen (H). In some embodiments, conformally depositing a molybdenum film in process 120 comprises chemical vapor deposition (CVD). In some embodiments, conformally depositing a molybdenum film in process 120 comprises pulsed chemical vapor deposition (pCVD) in which one or both of the reactants are pulsed into a chamber.

[0039] In some embodiments, conformal depositing the molybdenum film is performed at a temperature in the range of 300°C to 700°C, e.g., 300°C to 650°C, 300°C to 600°C, 300°C to 550°C, or 300°C to 500°C, and at a pressure in the range of 1 Torr to 300 Torr, e.g., 10 Torr to 250 Torr, or 10 Torr to 200 Torr.

[0040] 2A-2C illustrate cross-sectional views of a deposition process on a substrate according to one or more embodiments that produces a low electrical resistance film on a dielectric layer. Referring initially to FIG. 2A, a substrate 202 is shown having a surface, such as a top surface 203, and a dielectric layer 204 on the top surface 203. Referring to FIG. 2B, in one or more embodiments, a deposition method 100 includes forming a nucleation layer 206 directly on the dielectric layer 204 on the top surface 203 of the substrate 202. Referring to FIG. 2C, in one or more embodiments, the deposition method 100 includes conformally depositing a molybdenum film 208 on the nucleation layer 206.

[0041] Substrate 202 can be any suitable substrate material. In one or more embodiments, substrate 202 comprises a semiconductor material, such as silicon (Si), carbon (C), germanium (Ge), silicon germanium (SiGe), gallium arsenide (GaAs), indium phosphate (InP), indium gallium arsenide (InGaAs), indium aluminum arsenide (InAlAs), germanium (Ge), silicon germanium (SiGe), other semiconductor materials, or any combination thereof. In one or more embodiments, substrate 202 comprises one or more of silicon (Si), germanium (Ge), gallium (Ga), arsenic (As), indium (In), phosphorus (P), or selenium (Se). In some embodiments, substrate 202 comprises one or more of titanium nitride (TiN), titanium silicide (TiSi), tungsten titanium silicide alloy, purified silicon (Si), boron-doped silicon germanium (SiGeB), purified silicon phosphide (SiP), titanium aluminum (TiAl), ruthenium (Ru), tungsten (W), and molybdenum (Mo). Although some examples of materials from which substrate 202 can be formed are provided, any material that can serve as the basis for passive and active electronic devices (e.g., transistors, memory, capacitors, inductors, resistors, switches, integrated circuits, amplifiers, optoelectronic devices, or any other electronic device) can be utilized.

[0042] In some embodiments, the substrate 202 may comprise a dielectric material, such as a silicon-containing dielectric material and / or a metal oxide dielectric material. In some embodiments, the substrate 202 may comprise a dielectric material such as, but not limited to, silicon oxide (SiOx), silicon suboxide, silicon nitride (SiN x ), silicon carbide (SiC x ), silicon carbonitride (SiC x N y ), silicon oxynitride (SiO x N y ), tantalum nitride (TaN), hafnium oxide (HfO x ), a low-k dielectric material, or a combination thereof.

[0043] Nucleation layer 206 can have any suitable thickness, in some embodiments, nucleation layer 206 has a thickness of 10 Å or less, including, for example, a thickness in the range of 0.5 Å to 10 Å, 1 Å to 9 Å, 2 Å to 8 Å, 3 Å to 8 Å, 4 Å to 7 Å, or 5 Å to 6 Å.

[0044] Advantageously, the conformally deposited molybdenum film 208 on the nucleation layer 206 has a resistivity that is at least 30% reduced compared to a titanium nitride (TiN) film having a conformally deposited molybdenum film deposited thereon. In some embodiments, when the nucleation layer 206 and the conformally deposited molybdenum film 208 have a combined thickness of about 100 Å, the nucleation layer 206 and the conformally deposited molybdenum film 208 define a film stack with a resistivity of 35 μΩ-cm or less. In some embodiments, when the nucleation layer 206 and the conformally deposited molybdenum film 208 have a combined thickness of about 100 Å, the resistivity of the film stack is in the range of 20 μΩ-cm to 35 μΩ-cm, including 25 μΩ-cm to 35 μΩ-cm, 20 μΩ-cm to 25 μΩ-cm, or 30 μΩ-cm to 35 μΩ-cm. In some embodiments, the resistivity of the film stack is about 31 μΩ-cm when the nucleation layer 206 and the conformally deposited molybdenum film 208 have a combined thickness of about 100 Å.

[0045] Another aspect of the present disclosure relates to a method that is part of a gap-fill process, whereby a molybdenum metal film is deposited on a dielectric surface having one or more high-aspect-ratio gap features, including vertical and / or horizontal gap features, with the molybdenum in the gap features forming a current-carrying horizontal interconnect. Without wishing to be bound by theory, the molybdenum-filled gap conformally deposited on a nucleation layer, according to one or more embodiments of the method described herein, improves the electrical operation of the integrated circuit by minimizing power loss and overheating in the integrated circuit having the molybdenum-filled gap.

[0046] 3A-3C, a method for filling a feature formed on an upper surface 303 of a substrate 302 is illustrated for a feature 300 having a gap defined by opposing sidewalls 320 and a bottom 330. The substrate 302 can include any of the non-limiting materials described above with respect to FIGS. 2A-2C. In the embodiment shown in FIGS. 3A-3C, the substrate 302 includes a dielectric region.

[0047] In one or more embodiments, referring to FIG. 3B , a method of filling a feature includes forming a nucleation layer 306 directly on a dielectric region including a top surface 303 within a feature 300 on a surface of a substrate 302, the feature 300 including at least one surface defining a via, the via including a bottom 330 and two opposing sidewalls 320 comprising a dielectric.

[0048] Referring to FIG. 3C, the method includes conformally depositing a molybdenum film 308 on the nucleation layer 306 to fill the feature 300, the conformally deposited molybdenum film 308 being substantially free of seams or voids.

[0049] While the drawings show a substrate 302 with a single feature 300 for illustrative purposes, one skilled in the art will understand that there may be more than one feature 300. The shape of the feature 300 may be any suitable shape, including, but not limited to, a trench and a cylindrical via. As used in this context, the term "feature" refers to any intentional surface irregularity. Suitable examples of features include, but are not limited to, a trench having a top, two sidewalls, and a bottom; a peak having a top and two sidewalls extending upward from the surface; and a via having a bottom and sidewalls extending downward from the surface. In some embodiments, the bottom of the via includes an open bottom defined or bounded by an underlying material, such as a dielectric material, which may also define two sidewalls; or the underlying material at the bottom may be a conductor, such as a metal (e.g., copper), which may be a different material. In one or more embodiments, at least one feature 300 includes one or more of a trench or a via. In certain embodiments, the at least one feature 300 comprises a via. In further embodiments, the terms "at least one feature 300" and "via 300" may be used interchangeably. The via 300 has a depth to a bottom 330 and a width between two opposing sidewalls 320. In some embodiments, the depth is in the range of 2 nm to 200 nm, 3 nm to 200 nm, 5 nm to 100 nm, 2 nm to 100 nm, or 50 nm to 100 nm. In some embodiments, the width is in the range of 10 nm to 100 nm, 10 nm to 20 nm, 10 nm to 50 nm, or 50 nm to 100 nm. In some embodiments, the via 300 has an aspect ratio (depth / width) in the range of 1:1 to 20:1, 5:1 to 20:1, 10:1 to 20:1, or 15:1 to 20:1.

[0050] In some embodiments, each of the processes of deposition method 100 occurs in the same processing chamber. In some embodiments, each of the processes of deposition method 100 occurs in a different processing chamber. In some embodiments, the different processing chambers are connected as part of a processing system. In some embodiments, the processes of deposition method 100 occur without breaking vacuum.

[0051] In some embodiments, one or more of the processes of the deposition method 100 are performed in situ. In some embodiments, one or more of the processes of the deposition method are performed ex situ. As used herein, the term "in situ" refers to each of the processes of the deposition method 100 being performed in the same processing chamber or in different processing chambers connected as part of a processing system, and each of the processes of the deposition method 100 being performed without a vacuum break. As used herein, the term "ex situ" refers to each of the processes of the deposition method 100 being performed in the same processing chamber or in different processing chambers, and one or more of the processes of the deposition method 100 being performed via a vacuum break.

[0052] In some embodiments, the molybdenum film 308 is laterally bounded by two opposing sidewalls 320 of at least one feature 300. As used in this context, "laterally bounded" means that the deposited material does not extend beyond the intersection of the top surface 303 and the two opposing sidewalls 320. In some embodiments, the molybdenum film 308 extends above at least one feature 300. In some embodiments, the molybdenum film 308 fills a via 300. As used in this context, a film that "fills a via" has a volume that occupies at least 95%, at least 98%, or at least 99% of the volume of the via 300. In some embodiments, the film that fills a via has a fill height in the range of 30 nm to 75 nm, including the range of 40 nm to 60 nm.

[0053] Embodiments of the present disclosure advantageously provide molybdenum films 308 having lower resistivity compared to molybdenum films deposited by processes other than those described herein (e.g., deposition method 100). Embodiments of the present disclosure advantageously provide molybdenum films 308 that are free or substantially free of voids and seams. As used in this context, "substantially free" means that, on an atomic basis, less than about 5%, including less than about 4%, less than about 3%, less than about 2%, less than about 1%, less than about 0.5%, and less than about 0.1%, of the total composition of the conformally deposited molybdenum film 308 contains voids and / or seams.

[0054] One or more embodiments of the present disclosure are directed to a non-transitory computer-readable medium comprising instructions that, when executed by a controller of a processing chamber, cause the processing chamber to perform the operations of deposition method 100. In some embodiments, the non-transitory computer-readable medium comprises instructions that, when executed by a controller of the processing chamber, cause the processing chamber to directly form a nucleation layer on a dielectric layer on a substrate surface by exposing the substrate surface to a molybdenum-containing precursor and a nucleation reactant (operation 110); and conformally deposit a molybdenum film on the nucleation layer (operation 120).

[0055] The present disclosure will now be described with reference to the following examples. Before describing certain exemplary embodiments of the present disclosure, it is to be understood that the present disclosure is not limited to the details of construction or process steps set forth in the following description. The present disclosure is capable of other embodiments and of being practiced or carried out in various ways. [Example]

[0056] Comparative Example 1: Deposition of molybdenum films on metal surfaces General Procedure: A substrate is placed in a processing chamber. A molybdenum-containing precursor selected from one or more of molybdenum pentachloride (MoCl5), molybdenum dioxide dichloride (MoO2Cl2), molybdenum oxytetrachloride (MoOCl4), or molybdenum hexafluoride (MoF6) is flowed over the substrate in the processing chamber, leaving a surface terminated with the molybdenum precursor. Unreacted precursor and by-products are then purged out of the processing chamber. A co-reactant containing hydrogen (H2) is then introduced into the chamber and reacts with the surface-bound molybdenum species. Again, excess co-reactant and by-products are removed from the chamber. The resulting material on the substrate is a molybdenum-containing film.

[0057] The general procedure was repeated until the molybdenum-containing film reached a predetermined thickness. In some embodiments, the predetermined thickness was about 100 Å. Molybdenum-containing films were deposited on a variety of substrate materials, including, but not limited to, titanium nitride (TiN), titanium silicide (TiSi), tungsten titanium silicide alloy, purified silicon (Si), boron-doped silicon germanium (SiGeB), purified silicon phosphide (SiP), titanium aluminum (TiAl), ruthenium (Ru), tungsten (W), and molybdenum (Mo).

[0058] When attempts were made to utilize the above general procedure to deposit molybdenum-containing films on dielectric surfaces including, but not limited to, tantalum nitride (TaN), uncleaned silicon (Si), oxide (Ox), silicon nitride (SiN), or hafnium oxide (HfOx), no molybdenum-containing films were formed on any of these dielectric surfaces.

[0059] Example 2: Deposition of molybdenum films on dielectric surfaces General Procedure: A substrate is placed in a processing chamber. A molybdenum-containing precursor selected from one or more of molybdenum pentachloride (MoCl5), molybdenum dioxide dichloride (MoO2Cl2), molybdenum oxytetrachloride (MoOCl4), or molybdenum hexafluoride (MoF6) is flowed onto the substrate in the processing chamber, leaving a surface terminated with the molybdenum precursor directly on the dielectric surface. Dielectric surfaces utilized include, but are not limited to, tantalum nitride (TaN), uncleaned silicon (Si), oxide (Ox), silicon nitride (SiN), or hafnium oxide (HfOx). Unreacted precursors and by-products are then purged out of the chamber. A co-reactant, including one or more of silane (SiH4), disilane (Si2H6), or diborane (B2H6), is then introduced into the chamber and reacts with the surface-bound molybdenum species. Again, excess co-reactant and by-products are removed from the processing chamber. The resulting material on the dielectric surface of the substrate is a molybdenum-containing nucleation layer.

[0060] A molybdenum-containing precursor selected from one or more of molybdenum pentachloride (MoCl5), molybdenum dioxide dichloride (MoOCl2), molybdenum oxytetrachloride (MoOCl4), or molybdenum hexafluoride (MoF6) is then flowed onto the molybdenum-containing nucleation layer on the dielectric surface of the substrate in the processing chamber, leaving a surface terminated with the molybdenum precursor directly on the molybdenum-containing nucleation layer. Unreacted precursors and by-products are then purged out of the chamber. A co-reactant containing hydrogen (H2) is then introduced into the chamber and reacts with the surface-bound molybdenum species (e.g., the molybdenum-containing nucleation layer). Again, excess co-reactant and by-products are removed from the processing chamber. The resulting material on the molybdenum-containing nucleation layer is a molybdenum-containing film.

[0061] The general procedure was repeated until the combined thickness of the molybdenum-containing nucleation layer and the molybdenum-containing film reached a predetermined value. In some embodiments, the combined thickness was about 100 Å. A molybdenum-containing nucleation layer was formed on each of the above dielectric surfaces (tantalum nitride (TaN), uncleaned silicon (Si), oxide (Ox), silicon nitride (SiN), or hafnium oxide (HfOx)). The general procedure was repeated to grow a molybdenum-containing film on the dielectric surface.

[0062] References throughout this specification to "one embodiment," "a particular embodiment," "one or more embodiments," or "an embodiment" mean that a particular feature, structure, material, or characteristic described in connection with an embodiment is included in at least one embodiment of the present disclosure. Thus, the appearances of the phrases "in one or more embodiments," "in an embodiment," "in one embodiment," or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment of the present disclosure. In one or more embodiments, the particular features, structures, materials, or characteristics may be combined in any suitable manner.

[0063] Although the disclosure herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the disclosure. It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed method and apparatus without departing from the spirit and scope of the disclosure. Therefore, it is intended that the disclosure cover modifications and variations that come within the scope of the appended claims and their equivalents.

Claims

1. 1. A deposition method comprising: forming a nucleation layer directly on a dielectric layer on a substrate surface by exposing the substrate surface to a molybdenum-containing precursor and a nucleation reactant; and conformally depositing a molybdenum film onto said nucleation layer; A method comprising:

2. The molybdenum-containing precursor is molybdenum pentachloride (MoCl ５ ), molybdenum dioxide dichloride (MoO ２ Cl ２ ), molybdenum oxytetrachloride (MoOCl ４ ), or molybdenum hexafluoride (MoF ６ 10. The deposition method of claim 1, comprising one or more of:

3. The nucleation reactant is silane (SiH ４ ), disilane (Si ２ H ６ ), or diborane (B ２ H ６ 10. The deposition method of claim 1, comprising one or more of:

4. 10. The deposition method of claim 1, wherein forming the nucleation layer is carried out at a temperature in the range of 300°C to 700°C and a pressure in the range of 1 Torr to 300 Torr.

5. 10. The deposition method of claim 1, wherein forming the nucleation layer comprises one or more of atomic layer deposition (ALD), co-flow of the molybdenum-containing precursor and the nucleation reactant, chemical vapor deposition (CVD), or pulsed chemical vapor deposition (pCVD).

6. 10. The deposition method of claim 1, wherein conformally depositing the molybdenum film comprises exposing the nucleation layer to the molybdenum-containing precursor and a molybdenum film reactant different from the nucleation reactant.

7. 7. The deposition method of claim 6, wherein conformally depositing the molybdenum film comprises one or more of atomic layer deposition (ALD), co-flow of the molybdenum-containing precursor and the molybdenum film reactant, chemical vapor deposition (CVD), or pulsed chemical vapor deposition (pCVD).

8. The molybdenum film reactant is hydrogen (H ２ 7. The deposition method of claim 6, comprising:

9. The deposition method of claim 1 , wherein the nucleation layer has a thickness of 10 Å or less.

10. 10. The deposition method of claim 1, wherein the nucleation layer and the conformally deposited molybdenum film define a film stack having a resistivity of 35 μΩ-cm or less when the nucleation layer and the conformally deposited molybdenum film have a combined thickness of about 100 Å.

11. 1. A method of filling features formed on a substrate surface, comprising: forming a nucleation layer directly on a dielectric region within the feature by exposing the dielectric to a molybdenum-containing precursor and a nucleation reactant, the feature including at least one surface defining a via, the via having a bottom and two sidewalls comprising the dielectric; and conformally depositing a molybdenum film onto the nucleation layer to fill the feature, wherein the conformally deposited molybdenum film is substantially seam and void free. A method comprising:

12. The dielectric is silicon oxide (SiO ｘ ), silicon nitride (SiN ｘ ), silicon carbide (SiCx), silicon carbonitride (SiCxNy), silicon oxynitride (SiOxNy), low-k dielectric materials, or combinations thereof.

13. The molybdenum-containing precursor is molybdenum pentachloride (MoCl ５ ), molybdenum dioxide dichloride (MoO ２ Cl ２ ), molybdenum oxytetrachloride (MoOCl ４ ), or molybdenum hexafluoride (MoF ６ 12. The method of claim 11, comprising one or more of:

14. The nucleation reactant is silane (SiH ４ ), disilane (Si ２ H ６ ), or diborane (B ２ H ６ 12. The method of claim 11, comprising one or more of:

15. 12. The method of claim 11, wherein forming the nucleation layer occurs at a temperature in the range of 300°C to 700°C and a pressure in the range of 1 Torr to 300 Torr.

16. 12. The method of claim 11, wherein forming the nucleation layer comprises one or more of atomic layer deposition (ALD), co-flow of the molybdenum-containing precursor and the nucleation reactant, chemical vapor deposition (CVD), or pulsed chemical vapor deposition (pCVD).

17. 12. The method of claim 11, wherein conformally depositing the molybdenum film comprises exposing the nucleation layer to the molybdenum-containing precursor and a molybdenum film reactant different from the nucleation reactant.

18. 20. The method of claim 17, wherein conformally depositing the molybdenum film comprises one or more of atomic layer deposition (ALD), co-flow of the molybdenum-containing precursor and the molybdenum film reactant, chemical vapor deposition (CVD), or pulsed chemical vapor deposition (pCVD).

19. 12. The method of claim 11, wherein the nucleation layer and the conformally deposited molybdenum film define a film stack having a resistivity of 35 μΩ-cm or less when the nucleation layer and the conformally deposited molybdenum film have a combined thickness of about 100 Å.

20. A non-transitory computer-readable medium, comprising: When executed by a controller of a processing chamber, the processing chamber: forming a nucleation layer directly on a dielectric layer on the substrate surface by exposing the substrate surface to a molybdenum-containing precursor and a nucleation reactant; and Conformally depositing a molybdenum film onto the nucleation layer. A non-transitory computer-readable medium containing instructions.

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