Method for depositing molybdenum metal films on dielectric surfaces of substrates and related semiconductor device structures

Abstract

This document discloses a method for depositing a molybdenum metal film on a dielectric surface of a substrate and a related semiconductor device structure. The method may include: providing a substrate comprising a dielectric surface into a reaction chamber; and depositing a molybdenum metal film directly on the dielectric surface, wherein the deposition includes: contacting the substrate with a first gaseous reactant comprising a molybdenum halide precursor; and contacting the substrate with a second gaseous reactant comprising a reducing agent precursor. A semiconductor device structure comprising a molybdenum metal film directly disposed on the surface of a dielectric material deposited by the method of this disclosure is also disclosed.

Description

[0001] This application is a divisional application of Chinese invention patent application filed on August 30, 2018 (application number: 201811003934.5, applicant: ASM IP Holdings Limited, invention title: method for depositing molybdenum metal film on dielectric surface of substrate and related semiconductor device structure). Technical Field

[0002] This disclosure generally relates to methods for depositing molybdenum metal films on the surface of a dielectric material substrate, and specific methods for depositing molybdenum metal films directly on the surface of a dielectric material using a cyclic deposition process. This disclosure also generally relates to semiconductor device structures including molybdenum metal films directly disposed on the surface of a dielectric material. Background Technology

[0003] Semiconductor device manufacturing processes in advanced technology nodes typically require existing deposition methods to form metal films, such as tungsten and copper films.

[0004] A common requirement for depositing metal films is that the deposition process is highly conformal. For example, conformal deposition is often required to uniformly deposit metal films over three-dimensional structures that include high aspect ratio features. Another common requirement for depositing metal films is that the deposition process can deposit continuous ultrathin films over large substrate areas. In the specific case where the metal film is conductive, it may be necessary to optimize the deposition process to produce low resistivity films.

[0005] Low-resistivity metal films commonly used in existing semiconductor device applications may include tungsten (W) and / or copper (Cu). However, tungsten and copper films typically require a thick barrier layer disposed between the metal film and the dielectric material. This thick barrier layer prevents the metallic material from diffusing into the underlying dielectric material, thereby improving device reliability and yield. However, thick barrier layers generally exhibit high resistivity, thus leading to an increase in the overall resistivity of the semiconductor device structure.

[0006] Cyclic deposition processes, such as atomic layer deposition (ALD) and cyclic chemical vapor deposition (CCVD), sequentially introduce one or more precursors (reactants) into a reaction chamber, where these precursors react with the substrate surface one at a time in sequence. Cyclic deposition processes have been proven to produce metallic films with excellent conformal properties and atomic-level thickness control.

[0007] Therefore, there is a need for methods and related semiconductor device structures that deposit and utilize low resistivity metal films deposited through conformal cyclic deposition processes. Summary of the Invention

[0008] This overview is provided to introduce a set of concepts in a simplified form. These concepts are further described in detail below in the exemplary embodiments of this disclosure. This overview is not intended to identify key or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter.

[0009] In some embodiments, a method is provided for depositing a molybdenum metal film on a dielectric material surface of a substrate using a cyclic deposition process. The method may include: providing a substrate comprising a dielectric surface into a reaction chamber; and depositing a molybdenum metal film directly on the dielectric surface, wherein the deposition includes: contacting the substrate with a first gaseous reactant comprising a molybdenum halide precursor; and contacting the substrate with a second gaseous reactant comprising a reducing agent precursor.

[0010] In some embodiments, a semiconductor device structure is provided. The semiconductor device structure may include: a substrate comprising one or more gap features, wherein the one or more gap features constitute the surface of a dielectric material; and a molybdenum metal film disposed in and filling the one or more gap features, wherein the molybdenum metal film is configured to be in direct contact with the surface of the dielectric material.

[0011] For the purpose of summarizing the invention and its advantages over the prior art, certain objectives and advantages of the invention have been described above. It should be understood, of course, that not all such objectives or advantages may be achieved according to any particular embodiment of the invention. Therefore, by way of example, those skilled in the art will recognize that the invention may be practiced or carried out in a manner that achieves or optimizes one or more advantages as taught or suggested herein, but not necessarily achieves other objectives or advantages as may be taught or suggested herein.

[0012] All these embodiments are intended to be within the scope of the invention disclosed herein. These and other embodiments will become apparent to those skilled in the art from the following detailed description of certain embodiments with reference to the accompanying drawings, and the invention is not limited to any particular embodiment disclosed. Attached Figure Description

[0013] Although this specification concludes with claims that specifically point out and expressly claim protection to the contents regarded as embodiments of the invention, the advantages of embodiments of the present disclosure may be more readily determined from the description of certain examples of embodiments of the present disclosure when read in conjunction with the accompanying drawings.

[0014] Figure 1 A non-limiting exemplary flowchart is illustrated, showing an atomic layer deposition process for depositing a molybdenum metal film directly on a dielectric surface according to embodiments of the present disclosure.

[0015] Figure 2A non-limiting exemplary flowchart is illustrated, showing a cyclic chemical vapor deposition process for directly depositing a molybdenum metal film on a dielectric surface according to embodiments of the present disclosure.

[0016] Figure 3 The illustration shows X-ray diffraction (XRD) data obtained from a molybdenum metal film deposited directly on a dielectric surface according to an embodiment of the present disclosure.

[0017] Figure 4A and 4B A schematic cross-sectional view of a semiconductor device structure comprising a molybdenum metal film deposited directly on a dielectric surface according to embodiments of the present disclosure is shown. Detailed Implementation

[0018] Although certain embodiments and examples are disclosed below, those skilled in the art will understand that the invention extends beyond the specifically disclosed embodiments and / or uses of the invention and obvious modifications and equivalents thereof. Therefore, it is intended that the scope of the invention be limited not to the specific disclosed embodiments described below.

[0019] The illustrations presented herein are not intended to be actual views of any particular material, structure, or device, but are merely idealized diagrams used to describe embodiments of this disclosure.

[0020] As used herein, the term “substrate” can refer to any one or more underlying materials on which devices, circuits or films can be formed.

[0021] As used herein, the term “cyclic deposition” can refer to the sequential introduction of one or more precursors (reactants) into a reaction chamber to deposit a film over a substrate and includes deposition techniques such as atomic layer deposition and cyclic chemical vapor deposition.

[0022] As used herein, the term “cyclic chemical vapor deposition” can refer to any process in which a substrate is sequentially exposed to one or more volatile precursors that react and / or decompose on the substrate to produce the desired deposition.

[0023] As used herein, the term "atomic layer deposition (ALD)" can refer to a vapor phase deposition process in which deposition cycles, preferably multiple consecutive deposition cycles, are performed in a processing chamber. Typically, during each cycle, a precursor is chemically adsorbed onto the deposition surface (e.g., a substrate surface or a previously deposited underlayer surface, such as material from a previous ALD cycle), thereby forming a monolayer or sub-monolayer that is not readily reacting with additional precursors (i.e., a self-limiting reaction). Subsequently, if necessary, reactants (e.g., another precursor or reactive gas) can be subsequently introduced into the process chamber to convert the chemically adsorbed precursor into the desired material on the deposition surface. Typically, this reactant is capable of further reacting with the precursor. Furthermore, a rinsing step may be utilized during each cycle to remove excess precursor and / or excess reactants and / or reaction byproducts from the process chamber after converting the chemically adsorbed precursor. Furthermore, when performed using alternating pulses of precursor composition, reactive gas, and purging (e.g., inert support) gas, the term "atomic layer deposition" as used herein is also intended to include processes specified by related terms such as "chemical vapor deposition," "atomic layer epitaxy (ALE)," molecular beam epitaxy (MBE), gas source MBE, or organometallic MBE and chemical beam epitaxy.

[0024] As used herein, the terms “membrane” and “thin film” can refer to any continuous or discontinuous structure and material formed by the methods disclosed herein. For example, “membrane” and “thin film” can include 2D materials, nanolayers, nanorods, nanotubes, or nanoparticles, or even partial or complete molecular layers, partial or complete atomic layers, or clusters of atoms and / or molecules. “Membrane” and “thin film” may contain materials or layers with pinholes, but are still at least partially continuous.

[0025] As used herein, the term "molybdenum halide precursor" may refer to a reactant comprising at least a molybdenum component and a halide component, wherein the halide component may include one or more of a chlorine component, an iodine component, or a bromine component.

[0026] As used herein, the term "chalcogenide molybdenum halide" may refer to a reactant comprising at least a molybdenum component, a halide component, and a chalcogenide component, wherein the chalcogenides are elements in Group IV of the periodic table, including oxygen (O), sulfur (S), selenium (Se), and tellurium (Te).

[0027] As used herein, the term "molybdenum oxyhalide" may refer to a reactant comprising at least a molybdenum component, an oxygen component, and a halogen component.

[0028] As used in this article, the term "reducing precursor" can refer to a reactant that donates electrons to another substance in a redox chemical reaction.

[0029] As used herein, the term "crystalline film" can refer to a film exhibiting at least short-range order or even long-range order of crystalline structure, and includes both monocrystalline and polycrystalline films.

[0030] As used herein, the term "gap feature" can refer to an opening or cavity disposed between two surfaces that are not planar. The term "gap feature" can also refer to an opening or cavity disposed between opposing inclined sidewalls of two protrusions extending vertically from the surface of a substrate, or between opposing inclined sidewalls of a recess extending vertically into the surface of a substrate; such a gap feature may be referred to as a "vertical gap feature." The term "gap feature" can also refer to an opening or cavity disposed between two opposing, essentially horizontal surfaces that define a horizontal opening or cavity; such a gap feature may be referred to as a "horizontal gap feature."

[0031] As used herein, the term "seam" can refer to a line or one or more voids formed by the adjacency of edges formed in a gap-filling metal, and a "seam" can be confirmed using scanning transmission electron microscopy (STEM) or transmission electron microscopy (TEM), wherein a "seam" exists if observation reveals a clear vertical line or one or more vertical voids in a vertical gap-filling metal or a clear horizontal line or one or more horizontal voids in a horizontal gap-filling metal. Numerous exemplary materials are given throughout the embodiments of this disclosure; it should be noted that the chemical formulas given for each exemplary material should not be construed as limiting, and the non-limiting exemplary materials given should not be limited to the given stoichiometry.

[0032] This disclosure includes a method for depositing a molybdenum metal film directly, i.e., without any intermediate layer, on the surface of a dielectric material. Molybdenum metal films can be used in many applications, such as low-resistivity gap filling, as padding layers for 3D-NAND, DRAM word line features, or as interconnect materials in CMOS logic applications. The ability to deposit a molybdenum metal film directly on a dielectric surface eliminates the need for an intermediate layer between the dielectric material and the molybdenum metal film, which allows for lower effective resistivity in logic applications, i.e., interconnects in CMOS structures, and lower effective resistivity in memory applications such as 3D-NAND and DRAM structures for word lines / bit lines.

[0033] Therefore, embodiments of this disclosure may include a method for directly depositing a molybdenum metal film on the dielectric surface of a substrate using a cyclic deposition process. The method may include: providing a substrate comprising a dielectric material surface into a reaction chamber; and directly depositing a molybdenum metal film on the dielectric surface, wherein the deposition includes: contacting the substrate with a first gaseous reactant comprising a molybdenum halide precursor; and contacting the substrate with a second gaseous reactant comprising a reducing agent precursor.

[0034] The methods disclosed herein for directly depositing molybdenum metal films on the dielectric surface of a substrate may include cyclic deposition processes, such as atomic layer deposition (ALD) or cyclic chemical vapor deposition (CCVD).

[0035] Non-limiting examples of cyclic deposition processes may include atomic layer deposition (ALD), where ALD is typically based on a self-limiting reaction, thereby using sequential and alternating pulses of reactants to deposit approximately one atomic (or molecular) monolayer of material in each deposition cycle. Deposition conditions and precursors are typically selected to provide a self-saturating reaction, such that an adsorbed layer of one reactant leaves a surface termination state that does not react with the gaseous reactants of the same reactant. The substrate is then contacted with different reactants, which react with the previous termination state to achieve continued deposition. Thus, each cycle of alternating pulses typically leaves no more than approximately one monolayer of the desired material. However, as mentioned above, those skilled in the art will recognize that more than one monolayer of material can be deposited in one or more ALD cycles, for example, if some gas-phase reactions occur, regardless of the alternation of the process.

[0036] In an ALD-type process for directly forming a molybdenum metal film on a dielectric surface, a deposition cycle may include: exposing the substrate to a first gaseous reactant, removing any unreacted first reactant and reaction byproducts from the reaction chamber, and exposing the substrate to a second gaseous reactant, followed by a second removal step. In some embodiments of this disclosure, the first gaseous reactant may contain a molybdenum precursor, and the second gaseous reactant may contain a reducing agent precursor.

[0037] Precursors can be separated using inert gases such as argon (Ar) or nitrogen (N2) to prevent gas-phase reactions between reactants and to achieve a self-saturating surface reaction. However, in some embodiments, the substrate is movable to contact the first and second gas-phase reactants separately. Because the reaction is self-saturating, strict temperature control of the substrate and precise dosage control of the precursors are generally not required. However, the substrate temperature is preferably such that any accompanying gaseous species neither condense into a monolayer nor decompose on the surface. Residual chemicals and reaction byproducts (if present) are removed from the substrate surface, for example, by rinsing the reaction space or by moving the substrate, before contacting the substrate with the next reactant. Undesirable gaseous molecules can be effectively removed from the reaction space using an inert rinsing gas. A vacuum pump can be used to assist rinsing.

[0038] Reactors capable of directly depositing molybdenum metal films on the surface of dielectric materials can be used in the circulating deposition process described herein. Such reactors include ALD reactors configured to provide precursors and CVD reactors. According to some embodiments, spray head reactors can be used. According to some embodiments, cross-flow, batch, small-batch, or space ALD reactors can be used.

[0039] In some embodiments of this disclosure, a batch reactor may be used. In some embodiments, a vertical batch reactor may be used. In other embodiments, the batch reactor includes a small-batch reactor configured to accommodate 10 or fewer wafers, 8 or fewer wafers, 6 or fewer wafers, 4 or fewer wafers, or 2 or fewer wafers. In some embodiments in which a batch reactor is used, the inter-wafer inhomogeneity is less than 3% (1 sigma), less than 2%, less than 1%, or even less than 0.5%.

[0040] The exemplary cyclic deposition process described herein can optionally be performed in a reactor or reaction chamber connected to a cluster tool. In a cluster tool, because each reaction chamber is dedicated to a specific process type, the temperature of the reaction chamber in each module can be kept constant, which increases productivity compared to a reactor in which the substrate is heated to the process temperature before each run. Additionally, the time required to change the reaction chamber pressure to the required process pressure level between substrates can be reduced in a cluster tool. In some embodiments of this disclosure, the exemplary cyclic deposition process for directly depositing molybdenum metal films on dielectric surfaces disclosed herein can be performed in a cluster tool comprising multiple reaction chambers, wherein each individual reaction chamber can be used to expose the substrate to a separate precursor gas and the substrate can be transferred between different reaction chambers to be exposed to multiple precursor gases, the transfer of the substrate being performed in a controlled environment to prevent oxidation / contamination of the substrate. In some embodiments of this disclosure, the cyclic deposition process for directly depositing film metal films on dielectric surfaces can be performed in a cluster tool comprising multiple reaction chambers, wherein each individual reaction chamber can be configured to heat the substrate to a different temperature.

[0041] Independent reactors can be equipped with loading locks. In this case, it is not necessary to cool the reaction chamber between each run.

[0042] According to some non-limiting embodiments of this disclosure, an ALD process can be used to deposit a molybdenum metal film directly on the surface of a dielectric material. In some embodiments of this disclosure, each ALD cycle may include two distinct deposition steps or stages. In a first stage of the deposition cycle (“Molybdenum Stage”), the substrate surface on which deposition is desired may be contacted with a first gaseous reactant comprising a molybdenum precursor, the first gaseous reactant being chemisorbed onto the surface of the substrate, thereby forming no more than about one monolayer of the reactant material on the surface of the substrate. In a second stage of deposition, the substrate surface on which deposition is desired may be contacted with a second gaseous reactant comprising a reducing agent precursor (“Reduction Stage”).

[0043] An exemplary atomic layer deposition process for directly depositing a molybdenum metal film on the surface of a dielectric material can be combined with Figure 1Understandably, this figure illustrates an exemplary atomic layer deposition process 100 for depositing a molybdenum metal film directly on a dielectric surface.

[0044] To be more detailed, Figure 1 An exemplary molybdenum deposition process 100 is illustrated, including a cyclic deposition stage 105. The exemplary atomic layer deposition process 100 may begin with process block 110, which includes providing a substrate containing a dielectric surface into a reaction chamber and heating the substrate to a desired deposition temperature.

[0045] In some embodiments of this disclosure, the substrate may include a planar substrate or a patterned substrate including high aspect ratio features such as trench structures, vertical gap features, horizontal gap features, and / or fin structures. The substrate may comprise one or more materials, including but not limited to semiconductor materials, dielectric materials, and metallic materials.

[0046] In some embodiments, the substrate may include semiconductor materials, such as, but not limited to, silicon (Si), germanium (Ge), germanium-tin (GeSn), silicon-germanium (SiGe), silicon-germanium-tin (SiGeSn), silicon carbide (SiC), or group III-V semiconductor materials.

[0047] In some embodiments, the substrate may include a dielectric material, such as, but not limited to, silicon-containing dielectric materials and metal oxide dielectric materials. In some embodiments, the substrate may include one or more dielectric surfaces comprising silicon-containing dielectric materials such as, but not limited to, silicon dioxide (SiO2), silicon suboxide, silicon nitride (Si3N4), silicon oxynitride (SiON), silicon oxycarbide (SiOC), silicon oxycarbonide (SiOCN), and silicon carbonitride (SiCN). In some embodiments, the substrate may include one or more dielectric surfaces comprising metal oxides such as, but not limited to, aluminum oxide (Al2O3), hafnium oxide (HfO2), tantalum oxide (Ta2O5), zirconium oxide (ZrO2), titanium oxide (TiO2), and hafnium silicate (HfSiO2). x ) and lanthanum oxide (La2O3).

[0048] In some embodiments of this disclosure, the substrate may include an engineered substrate, wherein a surface semiconductor layer is disposed above a body support, and an intervening buried oxide (BOX) is disposed therebetween.

[0049] Patterned substrates may include substrates that contain semiconductor device structures formed in or on the surface of the substrate. For example, a patterned substrate may contain portions of semiconductor device structures such as transistors and / or memory elements. In some embodiments, the substrate may contain a single-crystal surface and / or one or more subsurfaces, which may include non-single-crystal surfaces, such as polycrystalline surfaces and / or amorphous surfaces. Single-crystal surfaces may contain one or more of, for example, silicon (Si), silicon-germanium (SiGe), germanium-tin (GeSn), or germanium (Ge). Polycrystalline or amorphous surfaces may contain dielectric materials such as oxides, oxynitrides, carbon oxides, carbon oxynitrides, nitrides, or mixtures thereof.

[0050] The reaction chamber used for deposition can be an atomic layer deposition (ALD) chamber, a chemical vapor deposition (CVD) chamber, or any of the chambers described above. In some embodiments of this disclosure, the substrate can be heated to the deposition temperature required for the subsequent cyclic deposition stage 105. For example, the substrate can be heated to a temperature below approximately 800°C, or below approximately 700°C, or below approximately 600°C, or below approximately 500°C, or below approximately 400°C, or below approximately 300°C, or even below approximately 200°C. In some embodiments of this disclosure, the substrate temperature during the exemplary ALD process 100 can be between 200°C and 800°C, or between 400°C and 700°C, or between 500°C and 600°C.

[0051] In addition, to achieve the desired deposition temperature, i.e., the desired substrate temperature, the exemplary atomic layer deposition process 100 may also adjust the pressure within the reaction chamber during deposition to obtain the desired properties of the deposited molybdenum metal film and achieve direct deposition of the molybdenum metal film on the dielectric surface. For example, in some embodiments of this disclosure, the exemplary atomic layer deposition process 100 may be performed in a reaction chamber where the pressure is adjusted to be below 300 Torr, or below 200 Torr, or below 100 Torr, or below 50 Torr, or below 30 Torr, or even below 10 Torr. In some embodiments, the pressure within the reaction chamber during deposition may be adjusted between 10 Torr and 300 Torr, or between 30 Torr and 80 Torr, or even equal to or higher than 30 Torr.

[0052] After heating the substrate to the desired deposition temperature and adjusting the pressure in the reaction chamber, the exemplary atomic layer deposition process 100 can be continued through process frame 120 in a cyclic deposition stage 105, which includes contacting the substrate with a first gaseous reactant, particularly in some embodiments, contacting the substrate with a first gaseous reactant containing a molybdenum halide precursor, i.e., a molybdenum precursor.

[0053] In some embodiments of this disclosure, the molybdenum halide precursor may comprise a molybdenum chloride precursor, a molybdenum iodide precursor, or a molybdenum bromide precursor. For example, as a non-limiting example, the first gas-phase reactant may comprise molybdenum chloride, such as molybdenum pentachloride (MoCl5).

[0054] In some embodiments, the molybdenum halide precursor may comprise a molybdenum chalcogenide, and in specific embodiments, the molybdenum halide precursor may comprise a chalcogenide molybdenum halide. For example, the chalcogenide molybdenum halide precursor may comprise an oxymolybdenum halide selected from molybdenum oxychloride, molybdenum oxyiodide, or molybdenum oxybromide. In specific embodiments of this disclosure, the molybdenum precursor may comprise molybdenum oxychloride, including but not limited to molybdenum dioxide (IV) (MoO2Cl2).

[0055] In some embodiments of this disclosure, contacting the substrate with a first gaseous reactant containing a molybdenum halide precursor may include contacting the molybdenum halide precursor with the substrate for a period between about 0.1 seconds and about 60 seconds, between about 0.1 seconds and about 10 seconds, or between about 0.5 seconds and about 5.0 seconds. Furthermore, during the contact between the substrate and the molybdenum halide precursor, the flow rate of the molybdenum halide precursor may be less than 1000 sccm, or less than 500 sccm, or less than 100 sccm, or less than 10 sccm, or even less than 1 sccm. Additionally, during the contact between the substrate and the molybdenum halide precursor, the flow rate of the molybdenum precursor may be in the range of about 1 to 2000 sccm, about 5 to 1000 sccm, or about 10 to about 500 sccm.

[0056] If passed Figure 1 The exemplary atomic layer deposition process 100, which schematically illustrates the direct deposition of a molybdenum metal film on a dielectric surface, can be continued by purging the reaction chamber. For example, excess first gaseous reactants and reaction byproducts (if any) can be removed from the substrate surface, for example, by purging with an inert gas. In some embodiments of this disclosure, the purging process may include a purging cycle in which the substrate surface is purged for less than about 5.0 seconds, or less than about 3.0 seconds, or even less than about 2.0 seconds. Excess first gaseous reactants, such as excess molybdenum precursors and any possible reaction byproducts, can be removed by means of a vacuum generated by a pumping system in fluid communication with the reaction chamber.

[0057] After purging the reaction chamber with a purge cycle, the exemplary atomic layer deposition process 100 can continue through process frame 130 in a second stage of cyclic deposition stage 105, which includes contacting the substrate with a second gaseous reactant, particularly contacting the substrate with a second gaseous reactant containing a reducing agent precursor (“reducing precursor”).

[0058] In some embodiments of this disclosure, the reducing agent precursor may comprise at least one of the following: syngas (H2 + N2), ammonia (NH3), hydrazine (N2H4), alkyl-hydrazine (e.g., tert-butylhydrazine (C4H4)). 12N2), molecular hydrogen (H2), hydrogen atoms (H), hydrogen plasma, hydrogen radicals, hydrogen excited species, alcohols, aldehydes, carboxylic acids, boranes, or amines. In other embodiments, the reducing agent precursor may comprise at least one of the following: silane (SiH4), disilane (Si2H6), trisilane (Si3H8), germanane (GeH4), digermanane (Ge2H6), borane (BH3), or diborane (B2H6). In specific embodiments of this disclosure, the reducing agent precursor may comprise molecular hydrogen (H2).

[0059] In some embodiments of this disclosure, contacting the substrate with the reducing agent precursor may include a contact time between about 0.01 seconds and about 180 seconds, about 0.05 seconds and about 60 seconds, or about 0.1 seconds and about 10.0 seconds. Furthermore, during the contacting of the substrate with the reducing agent precursor, the flow rate of the reducing agent precursor may be less than 30 slm, or less than 15 slm, or less than 10 slm, or less than 5 slm, or less than 1 slm, or even less than 0.1 slm. Additionally, during the contacting of the substrate with the reducing agent precursor, the flow rate of the reducing agent precursor may be in the range of about 0.1 to 30 slm, about 5 to 15 slm, or equal to or greater than 10 slm.

[0060] An exemplary process 100 in which a molybdenum metal film is deposited directly on a dielectric surface after the substrate has been brought into contact with the reducing agent precursor can be continued by purging the reaction chamber. For example, excess reducing agent precursor and reaction byproducts (if any) can be removed from the substrate surface, for example by suction while an inert gas is flowing. In some embodiments of this disclosure, the purging process may include purging the substrate surface for a period of about 0.1 seconds to about 30 seconds, or about 0.5 seconds to about 3 seconds, or even about 1 second to 2 seconds.

[0061] After the second gaseous reactant, i.e., the reducing agent precursor (and any reaction byproducts), is purged from the reaction chamber, the cyclic deposition phase 105 of the exemplary atomic layer deposition process 100 can continue via decision gate 140, where decision gate 140 depends on the thickness of the deposited molybdenum metal film. For example, if the deposited molybdenum metal film is not thick enough for the desired device application, the cyclic deposition phase 105 can be repeated by returning to process block 120 and continuing with further deposition cycles, where a single deposition cycle may include contacting the substrate with the molybdenum halide precursor (process block 120), purging the reaction chamber, contacting the substrate with the reducing agent precursor (process block 130), and purging the reaction chamber again. The single deposition cycle of the cyclic deposition phase 105 may be repeated once or multiple times until a molybdenum metal film of the desired thickness is deposited over the substrate, particularly directly on the dielectric surface. Once the molybdenum metal film has been deposited to the desired thickness, the exemplary atomic layer deposition process 100 can exit via process block 150, and the substrate containing the dielectric surface and the molybdenum metal film deposited thereon can undergo further processing to form a device structure.

[0062] It should be understood that in some embodiments of this disclosure, the sequence of contacting the substrate with the first gas-phase reactant (e.g., a molybdenum precursor) and the second gas-phase reactant (e.g., a reduction precursor) may be such that the substrate is first contacted with the second gas-phase reactant, and then with the first gas-phase reactant. Additionally, in some embodiments, the cyclic deposition stage 105 of the exemplary process 100 may include contacting the substrate with the first gas-phase reactant once or multiple times, and then contacting the substrate with the second gas-phase reactant once or multiple times. Furthermore, in some embodiments, the cyclic deposition stage 105 of the exemplary process 100 may include contacting the substrate with the second gas-phase reactant once or multiple times, and then contacting the substrate with the first gas-phase reactant once or multiple times.

[0063] In some embodiments, the cyclic deposition process can be a hybrid ALD / CVD or cyclic CVD process. For example, in some embodiments, the growth rate of the ALD process may be lower than that of the CVD process. One way to increase the growth rate is to operate at a higher substrate temperature than typically used in the ALD process (thus affecting some parts of the chemical vapor deposition process), but still utilizing the sequential introduction of precursors; such a process may be referred to as cyclic CVD. In some embodiments, the cyclic CVD process may include the introduction of two or more precursors into the reaction chamber, wherein there may be overlapping time periods between the two or more precursors in the reaction chamber, resulting in both ALD deposition components and CVD deposition components. For example, the cyclic CVD process may include a continuous flow of one precursor and a periodic pulse of a second precursor entering the reaction chamber.

[0064] Therefore, in alternative embodiments of this disclosure, the molybdenum metal film can be directly deposited on the surface of the dielectric material using a cyclic chemical vapor deposition (CCVD) process. An exemplary cyclic chemical vapor deposition process 200 for directly depositing a molybdenum metal film on the dielectric surface will be combined with... Figure 2 Illustration. It should be noted that the cyclic deposition process 200 includes certain process frames that are related to... Figure 1 Some process blocks of the exemplary atomic layer deposition process 100 are equivalent or substantially equivalent; therefore, the equivalent process blocks will be briefly outlined, while the additional / modified process blocks will be described in more detail.

[0065] More specifically, an exemplary cyclic chemical vapor deposition process 200 may begin with process block 210, which includes providing a substrate comprising a dielectric surface into a reaction chamber and heating the substrate to a deposition temperature. Process block 110 has been combined with Figure 1 The process block 110 is described in detail, therefore, the details of process block 210 will not be repeated for the cyclic chemical vapor deposition process 200.

[0066] After heating the substrate to the desired deposition temperature and adjusting the reaction chamber pressure, the cyclic chemical vapor deposition process 200 can continue at process block 220, which includes continuously contacting the substrate with a reducing agent precursor. More specifically, the reducing agent precursor can be introduced into the reaction chamber and contacted with the substrate disposed in the reaction chamber at a flow rate of less than 30 slm, or less than 15 slm, or less than 10 slm, or less than 5 slm, or less than 1 slm, or even less than 0.1 slm. In some embodiments, during the contact of the substrate with the reducing agent precursor, the flow rate of the reducing agent precursor can be in the range of about 0.1 to 30 slm, about 5 to 15 slm, or equal to or greater than 10 slm. The reducing agent precursor may comprise any one or more of the reducing agent precursors described in detail in conjunction with process block 130 of the exemplary atomic layer deposition process 100.

[0067] The exemplary cyclic chemical vapor deposition process 200 can be continued by performing a cyclic deposition stage 205 via process block 230, which includes contacting the substrate with a molybdenum halide precursor. Unlike the exemplary atomic layer deposition process 100, in the cyclic chemical vapor deposition process 200, the molybdenum halide precursor and the reducing agent precursor are simultaneously present in the reaction chamber, thus contacting the substrate, particularly the dielectric surface of the substrate, simultaneously. In other words, process block 230 includes co-flowing the molybdenum halide precursor and the reducing agent precursor into the reaction chamber and contacting the substrate with a gas mixture containing at least the molybdenum halide precursor and the reducing agent precursor. The molybdenum halide precursor may comprise any or more of the molybdenum halide precursors described in detail in conjunction with process block 120 of the exemplary atomic layer deposition process 100.

[0068] In some embodiments of this disclosure, contacting the substrate with the molybdenum halide precursor (i.e., process block 230) may include contacting the molybdenum halide precursor with the substrate for a period between about 0.1 seconds and about 60 seconds, between about 0.1 seconds and about 10 seconds, or between about 0.5 seconds and about 5.0 seconds. Additionally, during the contact between the substrate and the molybdenum halide precursor, the flow rate of the molybdenum halide precursor may be less than 1000 sccm, or less than 500 sccm, or less than 100 sccm, or less than 10 sccm, or even less than 1 sccm. Furthermore, during the contact between the substrate and the molybdenum halide precursor, the flow rate of the molybdenum precursor may be in the range of about 1 to 2000 sccm, about 5 to 1000 sccm, or about 10 to about 500 sccm.

[0069] While maintaining the flow of the reducing agent precursor, the cyclic deposition phase 205 of the exemplary cyclic chemical vapor deposition process 200 can continue via decision gate 240, which depends on the thickness of the deposited molybdenum metal film. For example, if the deposited molybdenum metal film is not thick enough for the desired device application, the cyclic deposition phase 205 can be repeated by returning to process block 230 and introducing more molybdenum halide precursor pulses into the reaction chamber. The exemplary cyclic chemical vapor deposition process 200 thus includes continuously flowing the reducing agent precursor and periodically introducing molybdenum halide into the reaction chamber to deposit a molybdenum metal film directly on the dielectric surface. Once the molybdenum metal film has been deposited to the desired thickness, the exemplary cyclic chemical vapor deposition process 200 can exit via process block 250, and the substrate containing the dielectric surface and the molybdenum metal film directly deposited thereon can undergo further processing to form a device structure.

[0070] In alternative embodiments of this disclosure, an exemplary cyclic chemical vapor deposition process may include continuously flowing a molybdenum halide precursor and periodically introducing a reducing agent precursor into a reaction chamber to deposit a molybdenum metal film directly on a dielectric surface.

[0071] The exemplary deposition processes disclosed herein can deposit molybdenum metal films directly on a dielectric surface at growth rates of about 0.05 Å / cycle to about 10 Å / cycle, about 0.5 Å / cycle to about 5 Å / cycle, or even about 1 Å / cycle to about 2 Å / cycle. In some embodiments, the growth rate of the molybdenum metal film directly on the dielectric surface exceeds about 0.5 Å / cycle, exceeds about 1 Å / cycle, or even exceeds about 2 Å / cycle. In some embodiments of this disclosure, the molybdenum metal film can be deposited at a growth rate of about 1 Å / cycle.

[0072] The molybdenum metal film deposited by the methods disclosed herein can be a continuous film. In some embodiments, the molybdenum metal film can be continuous at a thickness of less than about 100 angstroms, or less than about 60 angstroms, or less than about 50 angstroms, or less than about 40 angstroms, or less than about 30 angstroms, or less than about 20 angstroms, or less than about 10 angstroms, or even less than about 5 angstroms. The continuity mentioned herein can be physical continuity or electrical continuity. In some embodiments of this disclosure, the thickness at which the material film is physically continuous can differ from the thickness at which the film is electrically continuous, and vice versa.

[0073] In some embodiments of this disclosure, the formed molybdenum metal film may have a thickness of about 20 angstroms to about 250 angstroms, or about 50 angstroms to about 200 angstroms, or even about 100 angstroms to about 150 angstroms. In some embodiments, the molybdenum metal film deposited according to some embodiments described herein may have a thickness greater than about 20 angstroms, or greater than about 30 angstroms, or greater than about 40 angstroms, or greater than about 50 angstroms, or greater than about 60 angstroms, or greater than about 100 angstroms, or greater than about 250 angstroms, or greater than about 500 angstroms or more. In some embodiments, the molybdenum metal film deposited according to some embodiments described herein may have a thickness less than about 250 angstroms, or less than about 100 angstroms, or less than about 50 angstroms, or less than about 25 angstroms, or less than about 10 angstroms, or even less than about 5 angstroms. In some embodiments, the molybdenum metal film deposited directly on the dielectric surface may have a thickness between about 100 angstroms and 250 angstroms.

[0074] In some embodiments of this disclosure, a molybdenum metal film can be directly deposited on a dielectric surface such that the molybdenum metal film may comprise a crystalline film. For example, Figure 3 The image illustrates X-ray diffraction (XRD) data obtained from a 150 Å thick molybdenum metal film deposited directly on the surface of alumina (Al2O3). Figure 3 The XRD data clearly demonstrate the crystalline nature of the molybdenum metal film, as indicated by the XRD peak labeled 300. In some embodiments, the molybdenum metal film may comprise a monocrystalline film. In some embodiments, the molybdenum metal film may comprise a polycrystalline film, wherein the plurality of grains comprising the polycrystalline molybdenum metal film may have grain sizes greater than 100 angstroms, or greater than 200 angstroms, or even greater than 250 angstroms. In some embodiments, the molybdenum metal film may comprise a body-centered cubic crystalline structure.

[0075] In some embodiments of this disclosure, a molybdenum metal film may be deposited on a dielectric surface having one or more high aspect ratio gap features, including vertical gap features and / or horizontal gap features. For example, Figure 4AA semiconductor device structure 400 is illustrated, comprising a dielectric material 402 having a vertically high aspect ratio gap feature 404, wherein the aspect ratio (height:width) may be greater than 2:1, or greater than 5:1, or greater than 10:1, or greater than 25:1, or greater than 50:1, or even greater than 100:1, where “greater than” as used in this example refers to a greater distance in the height of the gap feature. The deposition methods disclosed herein can be used to deposit a molybdenum metal film directly over the surface of the vertically high aspect ratio gap feature 404, as illustrated by molybdenum metal film 406. In some embodiments, the step coverage of the molybdenum metal film directly on the vertically high aspect ratio dielectric gap feature may be equal to or greater than about 50%, or greater than about 80%, or greater than about 90%, or greater than about 95%, or greater than about 98%, or about 99%, or greater.

[0076] As a non-limiting example, semiconductor device structure 400 may represent a partially fabricated CMOS logic device, wherein dielectric material 402 may include interlayer dielectric, and molybdenum metal film 406 may include metal gap filler to provide electrical connection to one or more transistor structures (not shown). Figure 4A As shown, the molybdenum metal film 406 is in direct contact with the dielectric material 402 without the need for an intermediate barrier layer material, thereby reducing the overall effective resistivity of the semiconductor device structure 400.

[0077] In some embodiments, a molybdenum metal film can be used for gap-filling metallization, and the molybdenum metal film can fill gap features, i.e., vertical high aspect ratio gap features, without forming seams, wherein a seam can refer to a line or one or more voids formed by the adjacency of edges formed in the gap-filling material, and the seam can be confirmed using scanning transmission electron microscopy (STEM) or transmission electron microscopy (TEM), wherein a seam exists if observation reveals a clear vertical line or one or more vertical voids in the gap-filling material.

[0078] As yet another non-restrictive example, Figure 4B A semiconductor device structure 408 is illustrated, comprising a dielectric material 410 having one or more horizontally high aspect ratio gap features 412, wherein the aspect ratio (height:width) may be greater than 1:2, or greater than 1:5, or greater than 1:10, or greater than 1:25, or greater than 1:50, or even greater than 1:100, where “greater than” as used in this example refers to a larger distance in the width of the gap feature. The deposition methods disclosed herein can be used to deposit a molybdenum metal film directly over the surface of the horizontally high aspect ratio gap feature 412, as illustrated by molybdenum metal film 414. In some embodiments, the step coverage of the molybdenum metal film directly on the horizontally high aspect ratio dielectric feature may be equal to or greater than about 50%, or greater than about 80%, or greater than about 90%, or greater than about 95%, or greater than about 98%, or about 99%, or greater.

[0079] As a non-limiting example embodiment, semiconductor device structure 408 may represent part of a partially manufactured memory device, wherein dielectric material 402 may comprise aluminum oxide (Al2O3) and molybdenum metal film 406 may comprise a metal gate structure.

[0080] Similar to vertical gap-filling processes, molybdenum metal films can be used for gap-filling metallization of horizontally high aspect ratio features without forming seams, as previously described.

[0081] In some embodiments of this disclosure, the molybdenum metal film deposited directly on the dielectric surface may comprise a low-resistivity molybdenum metal film. For example, in some embodiments, the molybdenum metal film may have a resistivity of less than 3000 μΩ-cm, or less than 1000 μΩ-cm, or less than 500 μΩ-cm, or less than 200 μΩ-cm, or less than 100 μΩ-cm, or less than 50 μΩ-cm, or less than 25 μΩ-cm, or less than 15 μΩ-cm, or even less than 10 μΩ-cm. As a non-limiting example, a molybdenum metal film may be deposited directly on the surface of the dielectric material to a thickness of approximately less than 100 angstroms, and this molybdenum metal film may exhibit a resistivity of less than 35 μΩ-cm. As yet another non-limiting example, a molybdenum metal film may be deposited directly on the surface of the dielectric material to a thickness of less than 200 angstroms, and this molybdenum metal film may exhibit a resistivity of less than 25 μΩ-cm.

[0082] In some embodiments of this disclosure, the method of directly depositing a molybdenum metal film on a dielectric surface may further include depositing a molybdenum metal film having a low atomic percentage (atoms) of impurities. For example, the molybdenum metal film of this disclosure may contain impurity concentrations of less than 5 atoms, less than 2 atoms, or even less than 1 atom. In some embodiments, the impurities disposed within the molybdenum metal film may contain at least oxygen and chlorine.

[0083] The exemplary embodiments of this disclosure described above do not limit the scope of the invention, as these embodiments are merely examples of embodiments of the invention, which is defined by the appended claims and their legal equivalents. Any equivalent embodiments are intended to be within the scope of the invention. In fact, various modifications to this disclosure will become apparent to those skilled in the art from the description, in addition to the alternative applicable combinations of elements shown and described herein. Such modifications and embodiments are also intended to fall within the scope of the appended claims.

Claims

1. A method for depositing a molybdenum metal film directly on the surface of a dielectric material substrate via a cyclic deposition process, the method comprising: A substrate containing a dielectric surface is provided into the reaction chamber; and The substrate is heated to a desired deposition temperature between 600°C and 700°C, and the pressure inside the reaction chamber is adjusted to a desired pressure between 30 Torr and 300 Torr. A molybdenum metal film is deposited directly on the dielectric surface using one or more deposition cycles, wherein the deposition includes: The substrate is brought into contact with a first gaseous reactant containing a molybdenum halide precursor; and The substrate is brought into contact with a second gaseous reactant containing a reducing agent precursor.

2. The method according to claim 1, wherein the reducing agent precursor comprises at least one of the following: hydrazine (N2H4), alkylhydrazine, alcohol, aldehyde, carboxylic acid, and wherein the second gaseous reactant is continuously contacted with the substrate through one or more cycles.

3. The method according to claim 1, wherein the molybdenum chloride comprises molybdenum pentachloride (MoCl5).

4. A method for depositing a molybdenum metal film directly on the dielectric material surface of a substrate via a cyclic deposition process, the method comprising: A substrate containing a dielectric surface is provided into the reaction chamber; The substrate is heated to a desired deposition temperature between 600°C and 700°C, and the pressure inside the reaction chamber is adjusted to a desired pressure between 30 Torr and 300 Torr. and A molybdenum metal film is deposited directly on the dielectric surface using one or more deposition cycles, wherein the deposition includes: The substrate is brought into contact with a first gaseous reactant containing a molybdenum halide precursor, wherein the molybdenum halide comprises molybdenum halide, a chalcogenide compound. and The substrate is brought into contact with a second gaseous reactant containing a reducing agent precursor.

5. The method according to claim 4, wherein the reducing agent precursor may comprise at least one of the following: hydrazine (N2H4), alkylhydrazine, alcohol, aldehyde, carboxylic acid.

6. The method of claim 4, wherein the second gaseous reactant is continuously contacted with the substrate through one or more cycles.

7. The method according to claim 4, wherein the chalcogenide molybdenum halide comprises molybdenum oxyhalide selected from the group consisting of molybdenum oxychloride, molybdenum oxyiodide, or molybdenum oxybromide.

8. The method according to claim 7, wherein the molybdenum oxychloride comprises sulfur (S), selenium (Se) and tellurium (Te).

9. The method according to any one of claims 1-8, wherein the dielectric surface comprises at least one of the following materials: silicon dioxide (SiO2), silicon suboxide, silicon nitride (Si3N4), silicon oxynitride (SiON), silicon oxycarbonate (SiOC), silicon oxycarbonitride (SiOCN), and silicon carbonitride (SiCN).

10. The method according to any one of claims 1-8, wherein the dielectric surface comprises at least one of the following materials: aluminum oxide (Al2O3), hafnium oxide (HfO2), tantalum oxide (Ta2O5), zirconium oxide (ZrO2), titanium oxide (TiO2), hafnium silicate (HfSiOx) and lanthanum oxide (La2O3).

11. The method according to any one of claims 1-8, wherein the second gas-phase reactant comprises an alkylhydrazine, an alcohol, an aldehyde, or a carboxylic acid.

12. The method of claim 11, wherein the deposition cycle is repeated once or multiple times.

13. The method according to any one of claims 1-8, wherein the second gas-phase reactant comprises an aldehyde or a carboxylic acid.

14. The method according to any one of claims 1-8, wherein depositing the molybdenum metal film comprises a cyclic chemical vapor deposition process.

15. The method of claim 14, wherein the cyclic chemical vapor process comprises periodically contacting the substrate with the first gaseous reactant and continuously contacting the substrate with the second gaseous reactant.

16. The method according to any one of claims 1-8, wherein the molybdenum metal film has a resistivity of less than 35 μΩ-cm at a thickness of less than 100 angstroms.

17. The method according to any one of claims 1-8, wherein the molybdenum film has a resistivity of less than 25 μΩ-cm at a thickness of less than 200 angstroms.

18. The method according to any one of claims 1-8, wherein the molybdenum metal film is a crystalline film.

19. The method of claim 18, wherein the crystalline molybdenum metal film has a plurality of crystalline grains with a grain size greater than 100 angstroms.

20. The method according to any one of claims 1-8, wherein the molybdenum metal film has an impurity concentration of less than 2 atomic percent.

21. The method according to any one of claims 1-8, wherein the molybdenum metal film deposition has a stepped coverage of more than 90 percent.

22. A semiconductor device structure comprising a molybdenum metal film disposed directly on the surface of a dielectric material deposited by any one of claims 1-21.

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