Conformal molybdenum deposition

Abstract

Embodiments of the present disclosure provide conformally deposited molybdenum films with reduced resistivity and methods of forming the same. The method 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 depositing a molybdenum film on the nucleation layer in a conformal manner. Another aspect of the present disclosure relates to a method as part of a gap filling process, including forming a nucleation layer directly on a dielectric region within one or more high aspect ratio gap features, including vertical gap features and / or horizontal gap features, and depositing a molybdenum film on the nucleation layer in a conformal manner to fill the features.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to metal film deposition. More specifically, embodiments of the present disclosure are directed to conformal molybdenum deposition. Background Art

[0002] As circuit integration schemes increase, the need for greater uniformity and process control with respect to layer thickness increases. Therefore, various techniques have been developed to deposit layers on substrates in a cost-effective manner while maintaining control over the properties of the layers. Chemical vapor deposition (CVD) is one of the most common deposition processes employed for depositing layers on substrates.

[0003] A variant of CVD that exhibits excellent step coverage is cyclic deposition or atomic layer deposition (ALD). ALD employs a chemical adsorption technique to deliver precursor molecules to a substrate surface in sequential cycles. An ALD cycle includes exposing the substrate surface to a first precursor, a purge gas, a second precursor, and the purge gas. The first and second precursors react to form a product compound as a film on the substrate surface. The ALD cycle is repeated to form the 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 have attractive material and conductive properties. These films have been proposed and tested for applications from the front-end to the back-end of semiconductor and microelectronic devices.

[0005] While not wishing to be bound by any particular theory or principle, it is generally believed that molybdenum cannot be deposited and grown directly on a dielectric surface, but molybdenum can be deposited and grown on a metallic surface.

[0006] Molybdenum films can be used as low-resistivity electrical connections in the form of vertical and / or horizontal interconnects through which current flows, as vias between adjacent metal layers, and as contacts between the first metal layer on the substrate and the device. For example, in both blanket and gap fill applications, a liner film (e.g., a TiN liner film) is typically deposited on a dielectric surface to achieve repeatable molybdenum deposition. In gap fill applications, TiN is deposited in the gap to achieve both low resistivity 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 metal layers to provide lower resistivity molybdenum films. Thus, there is a need for improved materials and methods for depositing metal films on dielectric surfaces to provide conformal molybdenum deposition with improved film properties. Summary of the invention

[0008] One or more embodiments of the present disclosure are directed to 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 on the nucleation layer.

[0009] Another embodiment of the present disclosure is directed to a method of filling a feature formed on a substrate surface. The method of filling a feature formed on a substrate surface 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 includes a bottom and two sidewalls, the sidewalls including the dielectric. The method further includes depositing a molybdenum film on the nucleation layer in a conformal manner to fill the feature, the conformally deposited molybdenum film being substantially free of seams and voids.

[0010] Further embodiments of the present disclosure are directed to a non-transitory computer readable medium comprising instructions which, 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 surface of a substrate by exposing the surface of the substrate to a molybdenum-containing precursor and a nucleation reactant; and conformally deposit a molybdenum film on the nucleation layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to be able to understand in detail the manner in which the above features of the present disclosure are described, a more specific description of the present disclosure briefly summarized above may be provided by reference to the embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that the accompanying drawings illustrate only typical embodiments of this disclosure and are therefore not to be construed as limiting the scope of this disclosure, as the disclosure may allow for other equivalent embodiments. The embodiments described herein are illustrated by way of example and are not limited to the figures of the accompanying drawings, in which similar reference numerals indicate similar elements.

[0012] Figure 1 A process flow chart of a deposition method according to one or more embodiments is shown;

[0013] Figure 2A depicts a schematic cross-sectional view of a dielectric layer on a substrate surface according to one or more embodiments;

[0014] Figure 2BAccording to one or more embodiments, Figure 2A A schematic cross-sectional view of a nucleation layer on a dielectric layer on a substrate surface is shown;

[0015] Figure 2C According to one or more embodiments, Figure 2B A schematic cross-sectional view of a metal film on a nucleation layer is shown;

[0016] Figure 3A depicts a schematic cross-sectional view of features on a substrate according to one or more embodiments;

[0017] Figure 3B According to one or more embodiments, Figure 3A A schematic cross-sectional view of a nucleation layer on a dielectric region of a feature on a substrate as shown; and

[0018] Figure 3C According to one or more embodiments, Figure 3B Schematic cross-sectional view of a conformally deposited metal film on a nucleation layer is shown. DETAILED DESCRIPTION

[0019] Before describing several exemplary embodiments of the present disclosure, it should be understood that the present disclosure is not limited to the details of construction or process steps recorded in the following description. The present disclosure is capable of other embodiments and can be practiced or carried out in various ways.

[0020] As used herein, the term "about" means approximately or close to, and in the context of a recorded numerical value or range, means a variation of ±15% or less of the value. For example, values ​​that differ by ±14%, ±10%, ±5%, ±2%, or ±1% will satisfy the definition of about.

[0021] As used in this specification and the appended claims, the term "substrate" or "wafer" refers to a surface or portion of a surface on which a process acts. 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. In addition, reference to a step of depositing on a substrate may refer to both a bare substrate and a substrate having one or more films or features deposited or formed thereon.

[0022] As used herein, "substrate" refers to any substrate or material surface formed on a substrate on which film processing is performed during a manufacturing process. For example, the substrate surface on which processing may be performed includes 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 includes one or more of titanium nitride (TiN), titanium silicide (TiSi), tungsten titanium silicide, clean silicon (Si), boron-doped silicon germanium (SiGeB), clean silicon phosphorus (SiP), titanium aluminum (TiAl), ruthenium (Ru), tungsten (W), and molybdenum (Mo). The substrate includes, but is not limited to, a semiconductor wafer.

[0023] 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 performing film treatments directly on 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 underlying layer as indicated by the context. Thus, for example, when a film / layer or portion of a film / layer has been deposited onto a substrate surface, the exposed surface of the newly deposited film / layer becomes the substrate surface.

[0024] As used herein, the term "substrate surface" refers to any substrate surface on which a layer may be formed. The substrate surface may have one or more features formed therein, one or more layers formed on the substrate surface, and combinations thereof. The shape of the feature may be any suitable shape, including but not limited to peaks, grooves, and cylindrical vias. As used in this regard, the term "feature" refers to any intentional surface irregularity. Suitable examples of features include but are not limited to grooves (having a top, two sidewalls, and a bottom), peaks (having a top and two sidewalls extending upward from the surface), and vias (having sidewalls extending downward from the surface and having a bottom). In some embodiments, the bottom of the via includes an open bottom defined or bounded by an underlying material (for example, 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 the same or different from the sidewall material.

[0025] As used in this specification and the appended claims, the term "selectively" refers to a process that acts more effectively on a first surface than on another, second surface. Such a process will be described as acting "selectively" on the first surface as compared to the second surface. The term "as compared to" as used in this context does not imply a physical orientation of one surface on top of another, but rather refers to a relationship to the thermodynamic or kinetic properties of a chemical reaction of one surface relative to another.

[0026] The term "on" indicates direct contact between elements. The term "directly on" indicates direct contact between elements without intervening elements.

[0027] As used in this specification and the appended claims, the terms "precursor," "reactant," "reactive gas," and the like are used interchangeably to refer to any gaseous species that can react with a substrate surface.

[0028] As used herein, "atomic layer deposition" or "cyclic deposition" refers to sequentially exposing two or more reactive compounds to deposit a layer of material on a substrate surface. The substrate or a portion of the substrate is separately exposed to two or more reactive compounds in a reaction zone introduced into a processing chamber. In a time-domain ALD process, the exposure to each reactive compound is separated by a time delay to allow each compound to adhere and / or react on the substrate surface and then be purged from the processing chamber. These reactive compounds are said to be exposed to the substrate sequentially. In a spatial ALD process, different portions of the substrate surface or material on the substrate surface are exposed to two or more reactive compounds simultaneously, so that any given point on the substrate is not substantially exposed to more than one reactive compound at the same time. As used in this specification and the appended claims, the term "substantially" used in this regard means that, as will be understood by those skilled in the art, due to diffusion, a small portion of the substrate may be exposed to multiple reactive gases at the same time, and the simultaneous exposure is unintentional.

[0029] In one aspect of a time-domain ALD process, a first reactive gas (i.e., a first precursor or compound A) is pulsed into a reaction region, followed by a first time delay. Next, a second precursor or compound B is pulsed into the reaction region, followed by a second delay. During each time delay, a purge gas (e.g., argon) is introduced into the processing chamber to purge the reaction region or otherwise remove any residual reactive compounds or reaction byproducts from the reaction region. Alternatively, the purge gas may flow continuously throughout the deposition process such that only the purge gas flows during the time delay between pulses of the reactive compound. The reactive compounds are pulsed alternately until a desired film or film thickness is formed on the substrate surface. Under either scheme, the ALD process of pulsing compound A, purge gas, compound B, and purge gas is a cycle. A cycle may start with either compound A or compound B, and continue the individual sequences of the cycles until a film having a predetermined thickness is achieved.

[0030] In an embodiment of a spatial ALD process, a first reactive gas and a second reactive gas (e.g., nitrogen) are delivered to a reaction region simultaneously, but separated by an inert gas curtain and / or a vacuum curtain. The substrate is moved relative to the gas delivery apparatus so that any given point on the substrate is exposed to the first reactive gas and the second reactive gas.

[0031] Embodiments of the present disclosure advantageously provide methods of improving the resistivity of a blanket molybdenum film deposited on an underlying molybdenum layer formed by the methods described in this disclosure.

[0032] Resistivity is an intrinsic property of a material and is a measure of the material's resistance to the movement of charge through the material. The resistivity of a material affects the electrical operation of integrated circuits. Low resistivity molybdenum films can minimize power loss and overheating in integrated circuit designs. Because the resistivity of the nucleation layer is typically greater than that of the bulk material, the thickness of the nucleation layer should be minimized to keep the overall resistance as low as possible. On the other hand, the molybdenum nucleation layer should be thick enough to completely cover the underlying substrate to support high-quality bulk deposition. Obtaining a thin nucleation layer is even more critical for narrow widths and / or high aspect ratios and thin features.

[0033] In addition to providing molybdenum-containing films with low resistivity, the methods described herein also provide films with good uniformity and adhesion to underlying materials. One or more embodiments provide methods in which a molybdenum nucleation layer is deposited directly on a dielectric surface. The inventors have unexpectedly discovered that a unique combination of a molybdenum-containing precursor and a nucleation reactant allows molybdenum to be deposited on a dielectric surface. Further embodiments advantageously provide methods of reducing stack resistivity for bottom-up gap fill of vias, and having improved molybdenum film properties.

[0034] Embodiments of the present disclosure are described by means of figures that illustrate components (e.g., transistors) and processes for forming transistors according to one or more embodiments of the present disclosure. The processes shown are merely illustrative of possible uses of the disclosed processes, and those skilled in the art will recognize that the disclosed processes are not limited to the described applications.

[0035] Figure 1 A process flow diagram depicting a deposition method 100 according to one or more embodiments of the present disclosure. At operation 110, the deposition method 100 includes forming a nucleation layer directly on a dielectric surface, for example, on a dielectric layer on a substrate, or on a dielectric region of a substrate. In some embodiments, at operation 110, the step of forming the nucleation layer directly on the dielectric surface includes exposing the substrate surface to a molybdenum-containing precursor and a nucleation reactant. Generally, the nucleation layer is a thin conformal layer that serves to facilitate subsequent formation of a bulk material on the thin conformal layer. As used herein, the term "nucleation layer" refers to a layer deposited on a dielectric surface that allows a bulk material (e.g., a molybdenum-containing film) to be formed on the layer. In some embodiments, the nucleation reactant is different from the molybdenum film reactant.

[0036] In some embodiments, in operation 110, the step of forming the nucleation layer includes one or more of atomic layer deposition (ALD), co-flowing of a molybdenum-containing precursor and a nucleation reactant, chemical vapor deposition (CVD), or pulsed chemical vapor deposition (pCVD).

[0037] In some embodiments, at operation 110, the step of forming the nucleation layer includes atomic layer deposition (ALD), which includes 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 one or more cycles of the purge gas.

[0038] In some embodiments, at operation 110, the step of forming the nucleation layer comprises a spatial ALD process, wherein a first reactive gas (e.g., a molybdenum-containing precursor) and a second reactive gas (e.g., a nucleation reactant) are simultaneously delivered to the reaction zone, but separated by an inert gas curtain and / or a vacuum curtain. In some embodiments, at operation 110, the step of forming the nucleation layer comprises co-flowing the molybdenum-containing precursor and the nucleation reactant. In some embodiments, at operation 110, the step of forming the nucleation layer comprises chemical vapor deposition (CVD). In some embodiments, at operation 110, the step of forming the nucleation layer comprises pulsed chemical vapor deposition (pCVD), wherein one or both of the reactants are pulsed into the chamber.

[0039] In some embodiments, the molybdenum-containing precursor includes one or more of molybdenum pentachloride (MoCl 5 ), molybdenum dioxide dichloride (MoO 2 Cl 2 ), molybdenum oxychloride tetrachloride (MoOCl 4 ), or molybdenum hexafluoride (MoF 6 ).

[0040] In some embodiments, the nucleating reactant includes one or more of silane (SiH4), disilane (Si2H6), or diborane (B2H6).

[0041] In one or more embodiments, at operation 110, the step of forming a nucleation layer directly on the dielectric surface is performed at a temperature in the range of 300°C to 700°C and at a pressure in the range of 1 Torr to 300 Torr; for example, in the range of 300°C to 650°C, in the range of 300°C to 600°C, in the range of 300°C to 550°C, or in the range of 300°C to 500°C; for example, in the range of 10 Torr to 250 Torr or at a pressure in the range of 10 Torr to 200 Torr.

[0042] The deposition method 100 includes, at operation 120, depositing a molybdenum film on the nucleation layer in a conformal manner. In some embodiments, at operation 120, the step of depositing the molybdenum film in a conformal manner includes exposing the nucleation layer to a molybdenum-containing precursor and a molybdenum film reactant different from the nucleation reactant. In some embodiments, the molybdenum-containing precursor includes one or more of molybdenum pentachloride (MoCl5), molybdenum dichloride (MoO2Cl2), molybdenum oxychloride (MoOCl4), or molybdenum hexafluoride (MoF6). In some embodiments, the molybdenum film reactant includes hydrogen (H2).

[0043] In one or more embodiments, at operation 120, the step of depositing the molybdenum film in a conformal manner includes one or more of atomic layer deposition (ALD), co-flow of a molybdenum-containing precursor and hydrogen (H2), chemical vapor deposition (CVD), or pulsed chemical vapor deposition (pCVD). In some embodiments, at operation 120, the step of depositing the molybdenum film in a conformal manner includes atomic layer deposition (ALD), which includes 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 one or more cycles of the purge gas.

[0044] In some embodiments, at operation 120, the step of depositing the molybdenum film in a conformal manner includes 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 region, but separated by an inert gas curtain and / or a vacuum curtain. In some embodiments, at operation 120, the step of depositing the molybdenum film in a conformal manner includes co-flowing a molybdenum-containing precursor and hydrogen (H2). In some embodiments, at operation 120, the step of depositing the molybdenum film in a conformal manner includes chemical vapor deposition (CVD). In some embodiments, at operation 120, the step of depositing the molybdenum film in a conformal manner includes pulsed chemical vapor deposition (pCVD), in which one or both of the reactants are pulsed into the chamber.

[0045] In some embodiments, the step of depositing a molybdenum film in a conformal manner is performed at a temperature in the range of 300°C to 700°C and at a pressure in the range of 1 Torr to 300 Torr; for example, in the range of 300°C to 650°C, in the range of 300°C to 600°C, in the range of 300°C to 550°C, or in the range of 300°C to 500°C; for example, in the range of 10 Torr to 250 Torr or at a pressure in the range of 10 Torr to 200 Torr.

[0046] FIG. 2A to FIG. 2C A cross-sectional view depicting a deposition process on a substrate according to one or more embodiments that produces a low resistivity film on a dielectric layer. Figure 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. Figure 2B In one or more embodiments, the deposition method 100 includes forming a nucleation layer 206 directly on the dielectric layer 204 on the top surface 203 of the substrate 202. Figure 2C In one or more embodiments, the deposition method 100 includes depositing a molybdenum film 208 on the nucleation layer 206 in a conformal manner.

[0047] The substrate 202 may be any suitable substrate material. In one or more embodiments, the substrate 202 includes a semiconductor material, such as silicon (Si), carbon (C), germanium (Ge), silicon germanium (SiGe), gallium arsenide (GaAs), indium phosphide (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, the substrate 202 includes one or more of silicon (Si), germanium (Ge), gallium (Ga), arsenic (As), indium (In), phosphorus (P), or selenium (Se). In some embodiments, the substrate 202 includes one or more of titanium nitride (TiN), titanium silicide (TiSi), titanium tungsten silicide, clean silicon (Si), boron-doped silicon germanium (SiGeB), clean silicon phosphorus (SiP), titanium aluminum (TiAl), ruthenium (Ru), tungsten (W), and molybdenum (Mo). Although several examples of materials from which substrate 202 may be made have been provided, any material that can be used as a basis for passive and active electronic devices (e.g., transistors, memories, capacitors, inductors, resistors, switches, integrated circuits, amplifiers, optoelectronic components, or any other electronic device) may be utilized.

[0048] In some embodiments, the substrate 202 may include a dielectric material, for example, a silicon-containing dielectric material and / or a metal oxide dielectric material. In some embodiments, the substrate 202 may include one or more dielectric surfaces (e.g., dielectric layer 204) including dielectric materials 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 ), low-κ dielectric materials, or a combination thereof.

[0049] The nucleation layer 206 may have any suitable thickness. In some embodiments, the nucleation layer 206 has a thickness less than or equal to The thickness of to to to to to or to The thickness is in the range of

[0050] Advantageously, the conformally deposited molybdenum film 208 on the nucleation layer 206 has a resistivity that is reduced by at least 30% 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 resistivity that is reduced by at least 30%. When the combined thickness of the nucleation layer 206 and the conformally deposited molybdenum film 208 is about 100 Å, the nucleation layer 206 and the conformally deposited molybdenum film 208 define a film stack having a resistivity of less than or equal to 35 μΩ-cm. 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 having a resistivity of less than or equal to 35 μΩ-cm. When the combined thickness of the film stack is about 20 μΩ-cm, the resistivity of the film stack is in the range of from 20 μΩ-cm to 35 μΩ-cm, including in the range of from 25 μΩ-cm to 35 μΩ-cm, in the range of from 20 μΩ-cm to 25 μΩ-cm, or in the range of from 30 μΩ-cm to 35 μΩ-cm. In some embodiments, when the nucleation layer 206 has a combined thickness of about 200 μΩ-cm with the molybdenum film 208 deposited in a conformal manner, the resistivity of the film stack is in the range of from 20 μΩ-cm to 35 μΩ-cm, including in the range of from 25 μΩ-cm to 35 μΩ-cm, in the range of from 20 μΩ-cm to 25 μΩ-cm, or in the range of from 30 μΩ-cm to 35 μΩ-cm. With a combined thickness of , the resistivity of the film stack is about 31 μΩ-cm.

[0051] Another aspect of the present disclosure relates to a method as part of a gap fill process. Thus, a molybdenum metal film is deposited on a dielectric surface having one or more high aspect ratio gap features (including vertical gap features and / or horizontal gap features), the molybdenum in the gap features forming horizontal interconnects through which current flows. Without wishing to be bound by theory, according to one or more embodiments of the methods described herein, the gap filled with molybdenum deposited in a conformal manner on a nucleation layer results in improved electrical operation of an integrated circuit by minimizing power loss and overheating in the integrated circuit having the molybdenum filled gap.

[0052] Reference FIG. 3A to FIG. 3C , a method of filling a feature formed on a top surface 303 of a substrate 302 is illustrated with respect to feature 300, wherein feature 300 has a gap defined by opposing sidewalls 320 and a bottom 330. Substrate 302 may include the above-described FIG. 2A to FIG. 2C Any non-limiting material described. FIG. 3A to FIG. 3C In the illustrated embodiment, substrate 302 includes a dielectric region.

[0053] In one or more embodiments, referring to Figure 3B , the method of filling a feature includes forming a nucleation layer 306 directly on a dielectric region, the 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, the sidewalls 320 including a dielectric.

[0054] Reference Figure 3CThe method includes conformally depositing a molybdenum film 308 on the nucleation layer 306 to fill the feature 300, the molybdenum film 308 being deposited in a conformal manner having substantially no seams or voids.

[0055] For illustrative purposes, a substrate 302 is shown with a single feature 300; however, one skilled in the art will appreciate 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 regard, the term "feature" means any intentional surface irregularity. Suitable examples of features include but are not limited to trenches (having a top, two sidewalls, and a bottom), peaks (having a top and two sidewalls extending upward from the surface), and vias (having sidewalls extending downward from the surface and having a bottom). In some embodiments, the bottom of the via includes an open bottom defined or bounded by an underlying material (for example, 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 a specific embodiment, at least one feature 300 includes a via. In yet further embodiments, the terms "at least one feature 300" and "via 300" are used interchangeably. Via 300 has a depth to bottom 330 and a width between two opposing sidewalls 320. In some embodiments, the depth is in the range of 2nm to 200nm, 3nm to 200nm, 5nm to 100nm, 2nm to 100nm, or 50nm to 100nm. In some embodiments, the width is in the range of 10nm to 100nm, 10nm to 20nm, 10nm to 50nm, or 50nm to 100nm. In some embodiments, 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.

[0056] In some embodiments, the operations of deposition method 100 are each performed in the same processing chamber. In some embodiments, the operations of deposition method 100 are each performed in different processing chambers. In some embodiments, the different processing chambers are connected as part of a processing system. In some embodiments, the operations of deposition method 100 are performed without an intervening vacuum break.

[0057] In some embodiments, one or more of the operations of the deposition method 100 are performed in situ without breaking vacuum. In some embodiments, one or more of the operations of the deposition method are performed ex situ. As used herein, the term "in situ" means that each of the operations of the deposition method 100 is performed in the same processing chamber or in different processing chambers connected as part of a processing system, such that each operation of the deposition method 100 is performed without an intervening vacuum break. As used herein, the term "ex situ" means that each of the operations of the deposition method 100 is performed in the same processing chamber or in different processing chambers, such that one or more of the operations of the deposition method 100 is performed with an intervening vacuum break.

[0058] 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 between the top surface 303 and the two opposing sidewalls 320. In some embodiments, the molybdenum film 308 extends over the at least one feature 300. In some embodiments, the molybdenum film 308 fills the via 300. As used in this context, a film that "fills the 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 the via has a fill height in the range from 30 nm to 75 nm, inclusive in the range from 40 nm to 60 nm.

[0059] Embodiments of the present disclosure advantageously provide a molybdenum film 308 having a reduced resistivity compared to a molybdenum film deposited by a process other than the processes described herein (e.g., deposition method 100). Embodiments of the present disclosure advantageously provide a molybdenum film 308 that is free or substantially free of voids and seams. As used in this regard, "substantially free" means that 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 molybdenum film 308 deposited in a conformal manner on an atomic basis includes voids and / or seams.

[0060] One or more embodiments of the present disclosure are directed to a non-transitory computer-readable medium that includes instructions that, when executed by a controller of a processing chamber, cause the processing chamber to perform operations of deposition method 100. In some embodiments, the non-transitory computer-readable medium includes instructions that, when executed by a controller of the 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 (operation 110); and conformally deposit a molybdenum film on the nucleation layer (operation 120).

[0061] The present disclosure is now described with reference to the following examples. Before describing several exemplary embodiments of the present disclosure, it should be understood that the present disclosure is not limited to the details of construction or process steps recorded in the following description. The present disclosure is capable of other embodiments and can be practiced or implemented in various ways.

[0062] Example

[0063] Comparative Example 1: Deposition of a Molybdenum Film on a Metal Surface

[0064] General Procedure: A substrate is placed in a processing chamber. A molybdenum-containing precursor selected from one or more of molybdenum pentachloride (MoCl5), molybdenum dichloride (MoO2Cl2), molybdenum oxychloride (MoOCl4) or molybdenum hexafluoride (MoF6) is flowed into the processing chamber over the substrate, leaving the molybdenum precursor capped surface. Unreacted precursor and byproducts are then purged from the processing chamber. Next, a co-reactant including hydrogen (H2) is then introduced into the chamber, which reacts with the surface-bound molybdenum species. Again, excess co-reactant and byproducts are removed from the chamber. The resulting material on the substrate is a molybdenum-containing film.

[0065] The general procedure is repeated until a predetermined thickness of the molybdenum-containing film is reached. In some embodiments, the predetermined thickness is about Molybdenum-containing films are deposited on various substrate materials, including but not limited to titanium nitride (TiN), titanium silicide (TiSi), titanium tungsten silicide, clean silicon (Si), boron-doped silicon germanium (SiGeB), clean silicon phosphorus (SiP), titanium aluminum (TiAl), ruthenium (Ru), tungsten (W), and molybdenum (Mo).

[0066] When attempting to deposit a Mo-containing film on a dielectric surface using the general procedure described above, the dielectric surface includes, but is not limited to, Tantalum Nitride (TaN), uncleaned Silicon (Si), Oxide (Ox), Silicon Nitride (SiN), or Hafnium Oxide (HfO x ), no molybdenum-containing film is formed on these dielectric surfaces.

[0067] Example 2: Deposition of Molybdenum Film on Dielectric Surface

[0068] General Procedure: A substrate is placed in a processing chamber. A molybdenum-containing precursor selected from one or more of molybdenum pentachloride (MoCl5), molybdenum dichloride (MoO2Cl2), molybdenum oxytetrachloride (MoOCl4), or molybdenum hexafluoride (MoF6) is flowed into the processing chamber over the substrate, leaving the molybdenum precursor terminated surface directly on the dielectric surface. The dielectric surface utilized includes, but is not limited to, tantalum nitride (TaN), uncleaned silicon (Si), oxide (Ox), silicon nitride (SiN), or hafnium oxide (HfO x). Unreacted precursors and byproducts are then purged from the chamber. Next, a co-reactant including one or more of silane (SiH4), disilane (Si2H6), or diborane (B2H6) is then introduced into the chamber, which reacts with the surface-bound molybdenum species. Again, excess co-reactant and byproducts are removed from the processing chamber. The resulting material on the dielectric surface of the substrate is a molybdenum-containing nucleation layer.

[0069] Thereafter, a molybdenum-containing precursor selected from one or more of molybdenum pentachloride (MoCl5), molybdenum dichloride (MoO2Cl2), molybdenum oxytetrachloride (MoOCl4) or molybdenum hexafluoride (MoF6) is flowed into the processing chamber over the molybdenum-containing nucleation layer on the dielectric surface of the substrate, thereby leaving the molybdenum precursor terminated surface directly on the molybdenum-containing nucleation layer. Unreacted precursor and byproducts are then purged from the chamber. Next, a co-reactant including hydrogen (H2) is then introduced into the chamber, which reacts with the surface-bound molybdenum species (e.g., the molybdenum-containing nucleation layer). Again, excess co-reactant and byproducts are removed from the processing chamber. The resulting material on the molybdenum-containing nucleation layer is a molybdenum-containing film.

[0070] The general procedure is repeated until a predetermined combined thickness of the molybdenum-containing nucleation layer and the molybdenum-containing film is reached. In some embodiments, the predetermined combined thickness is about The Mo-containing nucleation layer is formed on the above dielectric surface (Tantalum Nitride (TaN), uncleaned Silicon (Si), oxide (Ox), Silicon Nitride (SiN) or Hafnium Oxide (HfO x The general procedure is repeated to grow the molybdenum-containing film on the dielectric surface.

[0071] References throughout this specification to "one embodiment," "certain 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, phrases such as "in one or more embodiments," "certain embodiments," "in an embodiment," or "in an embodiment" appearing in various places throughout this specification are not necessarily referring to the same embodiment of the present disclosure. In one or more embodiments, the particular features, structures, materials, or characteristics are combined in any suitable manner.

[0072] Although the disclosure herein has been described with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the disclosure. It will be apparent to those skilled in the art that various modifications and variations may be made to the methods and apparatus of the disclosure without departing from the spirit and scope of the disclosure. Therefore, it is contemplated that the disclosure includes modifications and variations within the scope of the appended claims and their equivalents.

Claims

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

2. The deposition method of claim 1, wherein the molybdenum-containing precursor comprises one or more of molybdenum pentachloride (MoCl5), molybdenum dioxide dichloride (MoO2Cl2), molybdenum oxychloride tetrachloride (MoOCl4) or molybdenum hexafluoride (MoF6).

3. The deposition method of claim 1, wherein the nucleation reactant comprises one or more of silane (SiH4), disilane (Si2H6) or diborane (B2H6). 4 . The deposition method of claim 1 , wherein the step of forming the nucleation layer is performed at a temperature in a range of 300° C. to 700° C. and at a pressure in a range of from 1 Torr to 300 Torr.

5. The deposition method of claim 1, wherein the step of 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. The deposition method of claim 1, wherein the step of depositing the molybdenum film in a conformal manner comprises: The nucleation layer is exposed to the molybdenum-containing precursor and a molybdenum film reactant, the molybdenum film reactant being different from the nucleation reactant.

7. A deposition method as described in claim 6, wherein the step of depositing the molybdenum film in a conformal manner includes 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 deposition method of claim 6, wherein the molybdenum film reactant comprises hydrogen (H2).

9. The deposition method of claim 1, wherein the nucleation layer has a thickness less than or equal to Thickness.

10. The deposition method of claim 1, wherein when the nucleation layer has a thickness of about 1.0 mm with respect to the conformally deposited molybdenum film, When the combined thickness is , the nucleation layer and the conformally deposited molybdenum film define a film stack having a resistivity less than or equal to 35 μΩ-cm.

11. A method of filling a feature formed on a surface of a substrate, the method 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 comprising at least one surface defining a via, the via comprising a bottom and two sidewalls, the two sidewalls comprising the dielectric; and A molybdenum film is conformally deposited on the nucleation layer to fill the features, the conformally deposited molybdenum film being substantially free of seams and voids.

12. The method of claim 11, wherein the dielectric comprises silicon oxide (SiO x ), Silicon Nitride (SiN x ), Silicon Carbide (SiC x ), Silicon Carbonitride (SiC x N y ), silicon oxynitride (SiO x N y ), low-κ dielectric materials, or a combination thereof.

13. The method of claim 11, wherein the molybdenum-containing precursor comprises one or more of molybdenum pentachloride (MoCl5), molybdenum dioxide dichloride (MoO2Cl2), molybdenum oxychloride tetrachloride (MoOCl4), or molybdenum hexafluoride (MoF6).

14. The method of claim 11, wherein the nucleating reactant comprises one or more of silane (SiH4), disilane (Si2H6), or diborane (B2H6).

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

16. The method of claim 11, wherein the step of 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. The method of claim 11, wherein the step of depositing the molybdenum film in a conformal manner comprises: The nucleation layer is exposed to the molybdenum-containing precursor and a molybdenum film reactant, the molybdenum film reactant being different from the nucleation reactant.

18. A method as claimed in claim 17, wherein the step of depositing the molybdenum film in a conformal manner includes 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. The method of claim 11, wherein when the nucleation layer has a thickness of about When the combined thickness is , the nucleation layer and the conformally deposited molybdenum film define a film stack having a resistivity less than or equal to 35 μΩ-cm.

20. A non-transitory computer readable medium comprising instructions which, when executed by a controller of a processing chamber, cause the processing chamber to: forming a nucleation layer directly on the dielectric layer on the substrate surface by exposing the substrate surface to a molybdenum-containing precursor and a nucleation reactant; and A molybdenum film is conformally deposited on the nucleation layer.

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