Method for reducing or eliminating defects in tungsten films

Abstract

Methods and apparatus for reducing and eliminating defects in tungsten films are disclosed herein. In the present disclosure, steps are disclosed for reducing or eliminating oxidation of a first surface of a tungsten film having a predetermined first thickness disposed on a substrate and within a plurality of trenches. The plurality of trenches include a predetermined depth and a width of less than 20 nanometers. When the first surface is in contact with air or oxygen, the predetermined first thickness of the tungsten film is substantially uniform throughout the plurality of trenches, such that the predetermined first thickness of the tungsten film does not substantially change to a second thickness.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to processing of semiconductor substrates. In particular, embodiments of the present disclosure relate to depositing a tungsten layer on a semiconductor substrate using a vapor deposition technique. Background Art

[0002] The semiconductor processing industry continues to strive for greater throughput while increasing the uniformity of the layers deposited on the substrate. These same factors combined with new materials also provide for higher integration of circuits per unit area of ​​the substrate. As circuit integration increases, the demand for greater uniformity of layer thickness and process control also increases. Therefore, various techniques have been developed to deposit layers on the substrate in a cost-effective manner while maintaining control over the properties of the layers.

[0003] Chemical vapor deposition (CVD) is one of the most common deposition processes used to deposit layers on substrates. CVD is a flux-dependent deposition technique that involves precise control of substrate temperature and precursors introduced into the process chamber in order to produce a layer of desired uniform thickness. As feature sizes such as trenches and vias decrease, these processing parameters become more critical, requiring greater sophistication to maintain uniformity.

[0004] A CVD variant that exhibits excellent step coverage is cyclical deposition or atomic layer deposition (ALD). Cyclic deposition is based on atomic layer epitaxy (ALE) and uses chemical adsorption techniques to deliver precursor molecules on the substrate surface in a continuous cycle. The cycle exposes the substrate surface to a first precursor, a purge gas, a second precursor, and a purge gas. The first and second precursors react to form a product compound as a film on the substrate surface. The cycle is repeated to form the layer to a desired thickness.

[0005] However, the inventors have found that depositing tungsten by conventional CVD and ALD methods has several disadvantages. For example, defects are the main device loss factor formed during the manufacture of semiconductor devices, and these defects lead to device yield loss. As the features of semiconductor devices shrink to below the 20 nanometer range, the inventors have observed new defects in logic metal gates and contacts, NAND and other memory structures. In tungsten-related vapor deposition processes (ALD and CVD), a defect is found in small grooves, such as grooves with a width of less than 20 nanometers. For example, filamentary defects may be formed in the lower part of the feature or groove. These defects include WO formed after tungsten or tungsten films (such as those formed by organic-based processes) are in contact with or exposed to air or oxygen. x(x is an integer, such as 1-3 in an embodiment) defect. The defect appears as a filamentous deposit or residue that can destroy the conformality of the layer or appear as a deposit that reduces the depth of the feature or groove compared to other features without defects. Defects such as filamentous defects are generally not observed in larger grooves, such as grooves with a width greater than 20 nanometers. Such defects are problematic for continuous processing such as deposition, patterning, and similar processes. For example, the use of tungsten hinders the manufacturing process because defects on the lower surface of narrow grooves hinder the ability to uniformly deposit additional layers or films thereon (as needed). In addition, the inventors have found that filamentous defects are unpredictable and difficult to monitor and control.

[0006] Accordingly, the present inventors have provided improved methods of depositing tungsten layers and tungsten-containing layers. Summary of the invention

[0007] Methods and apparatus for depositing a tungsten layer on a semiconductor substrate using a vapor deposition technique are provided herein. In some embodiments, a method for reducing or eliminating defects in a tungsten film includes: reducing or eliminating oxidation of a first surface of a tungsten film having a predetermined first thickness disposed on a substrate and within a plurality of trenches, wherein the plurality of trenches include a predetermined depth and a width of less than 20 nanometers, and wherein when the first surface is in contact with oxygen, the predetermined first thickness is substantially uniform throughout the plurality of trenches, such that the predetermined first thickness does not substantially change to a second thickness.

[0008] In some embodiments, a method of depositing a tungsten film includes depositing a tungsten film having a first surface and a predetermined first thickness on a substrate and in a plurality of trenches, wherein the plurality of trenches include a predetermined depth and a width less than 20 nanometers, and wherein when the first surface is in contact with oxygen, the predetermined first thickness is substantially uniform in the plurality of trenches such that the predetermined first thickness does not substantially change to a second thickness.

[0009] A method for reducing or eliminating defects in a tungsten film comprises: depositing a tungsten film having a first surface and a predetermined first thickness on a substrate and in a plurality of grooves, wherein the plurality of grooves comprise a predetermined depth and a width less than 20 nanometers; contacting the first surface with a halide type metal precursor; and contacting the first surface with oxygen, wherein upon contact with oxygen, the predetermined first thickness is substantially uniform throughout the plurality of grooves so as not to substantially change to a second thickness.

[0010] Other and further embodiments of the disclosure are described below.

[0011] BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Embodiments of the present disclosure briefly summarized above and discussed in more detail below may be understood by reference to the illustrative embodiments of the present disclosure depicted in the accompanying drawings. However, the drawings illustrate only typical embodiments of the present disclosure and are therefore not to be considered limiting of scope, as the present disclosure may admit to other equally effective embodiments.

[0013] Figure 1 A flow chart for reducing or eliminating defects in a tungsten film according to an embodiment of the present disclosure is depicted.

[0014] Figures 2A to 2C The fabrication stages of depositing a tungsten film according to an embodiment of the present disclosure are respectively depicted.

[0015] Figure 3 is a processing chamber suitable for performing deposition processes according to some embodiments of the present disclosure.

[0016] Figure 4 is a flow chart of a method of depositing a tungsten film according to one embodiment of the present disclosure.

[0017] Figure 5 is a flow chart of a method of reducing or eliminating defects in a tungsten film according to one embodiment of the present disclosure.

[0018] For ease of understanding, the same reference numerals are used as much as possible to represent the same elements in common in the drawings. The drawings are not drawn to scale and may be simplified for clarity. Elements and features of one embodiment may be advantageously incorporated into other embodiments without further description. DETAILED DESCRIPTION

[0019] Embodiments of the present disclosure provide methods of reducing or eliminating defects in tungsten films. Although not intended to be limiting of the present disclosure, embodiments of the present disclosure are useful when depositing tungsten in one or more trenches having a width of 20 nanometers or less.

[0020] The inventors have observed that by reducing or eliminating oxidation of tungsten after CVD and ALD deposition, defects formed in one or more trenches having a width of 20 nanometers or less can be advantageously reduced or eliminated. Reducing or eliminating defects in the finished tungsten layer results in increased device yield, reduced manufacturing costs, and increased uniformity throughout multiple features during semiconductor device formation. The increased uniformity enhances the application of additional processing layers as manufacturing continues. The inventors have also found that methods according to the present disclosure advantageously reduce or eliminate filamentary defects or WO when ALD and CVD are used under different processing conditions. xThe formation of defects. Thus, embodiments of the present disclosure can be advantageously used during different CVD and ALD processes. In some embodiments, the methods of the present disclosure advantageously provide tungsten films with significantly improved surface uniformity and production level yield. In embodiments, high quality control is maintained when the tungsten film is in contact with air and oxygen.

[0021] Figure 1 is a flow chart of a method 100 for reducing or eliminating defects in a tungsten film according to some embodiments of the present disclosure. Figures 2A to 2C The method 100 of the stage of depositing a tungsten film shown is described below and can be performed, for example, in a suitable cluster tool and processing chamber. Exemplary processing systems that can be used to perform the methods disclosed herein can include, but are not limited to, the TECHNOLOGY SYSTEM commercially available from Applied Materials, Inc. located in Santa Clara, California. or Any of the processing systems of the brands of TUNA®. Non-limiting examples of suitable cluster tools and processing chambers are disclosed in commonly owned U.S. Patent No. 7,405,158, issued to Lai et al. on July 29, 2008, entitled “Method for Depositing a Tungsten Layer Using Atomic Layer Deposition Techniques.” Other processing chambers include Figure 3 Process chambers from , as well as process chambers available from other manufacturers, may also be suitably used in conjunction with the teachings provided herein.

[0022] The method 100 is generally directed to providing a processing volume (e.g., Figure 3 In some embodiments, the process may be performed by placing a substrate 200 in an inner space 305 of a processing chamber 302. Figure 2A As shown, the substrate 200 includes one or more features, such as a trench 202 ( Figures 2A to 2C ), a groove 202 extending toward a base 204 of the substrate 200. Although described below with respect to one feature, the substrate 200 may include any number of features (such as a plurality of grooves 202, vias, or the like) as described below. For example, referring to Figure 2A , n refers to an integer representing the number of grooves 202 in the substrate 200. In an embodiment, n may be 1 or greater than 1, representing a plurality of grooves 202 in the substrate 200. For example, if n=5, then Figure 2A Five trenches, such as trench 202 in a single substrate 200 will be represented.

[0023] The substrate 200 may be any suitable substrate having a groove 202 formed in the substrate 200. For example, the substrate 200 may include one or more of silicon (Si), silicon oxide (SiO2), or the like. In an embodiment, the substrate 200 may include a groove 202 formed in a dielectric layer, such as a low-k material (e.g., a material having a dielectric constant less than silicon oxide, or less than about 3.9) or the like. In addition, the substrate 200 may include additional material layers, or may have one or more completed or partially completed structures or devices (not shown) formed in or on the substrate 200. In an embodiment, the substrate 200 may be, for example, a doped or undoped silicon substrate, a III-V compound substrate, a silicon germanium (SiGe) substrate, an epitaxial substrate, a silicon on insulator (SOI) substrate, a display substrate such as a liquid crystal display (LCD), a plasma display, an electroluminescent (EL) lamp display, a light emitting diode (LED) substrate, a solar cell array, a solar cell panel, or the like. In some embodiments, the substrate 200 may be a semiconductor wafer.

[0024] The substrate 200 is not limited to any particular size or shape. The substrate may be a circular wafer having a diameter of 200 mm, a diameter of 300 mm, or other diameters, such as 450 mm, etc. The substrate may also be any polygonal, square, rectangular, curved, or other non-circular workpiece, such as a polygonal glass substrate used to manufacture a flat panel display.

[0025] The substrate 200 may be etched using any suitable etching process to form a trench 202 or a plurality of trenches or features. In some embodiments, the trench 202 is defined by one or more sidewalls 214, a bottom surface 206, and an upper corner 221. In some embodiments, the trench 202 may have a high aspect ratio, for example, an aspect ratio between about 5:1 and about 20:1. As used herein, an aspect ratio is the ratio of the depth of a feature to the width of the feature. In an embodiment, the trench 202 has a width 209 less than or equal to 20 nanometers, less than or equal to 10 nanometers, or a width 209 between 5 and 10 nanometers, between 5 and 15 nanometers, or between 1 and 20 nanometers. In an embodiment, the width 209 is approximately 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, or 19 nanometers.

[0026] Reference Figures 2A to 2C , the bottom layer (not shown) may optionally be placed in a processing chamber (e.g. Figure 3in the processing chamber 302) is deposited on the substrate 200 and within the trench 202, and the processing chamber is configured to deposit a layer. The underlying layer may be a layer conformally formed along at least a portion of the sidewall 214 and / or the bottom surface 206 of a feature such as the trench 202, such that most of the feature before deposition of the layer remains unfilled after deposition of the layer. In some embodiments, the underlying layer may be formed along the entire sidewall 214 and bottom surface 206 of the trench 202. The underlying layer may be a wetting layer that is provided to enhance the adhesion of a metal layer disposed on the underlying layer.

[0027] Reference Figure 2B , shows a tungsten layer 208 deposited on top of the substrate 200 and within the trench 202. In an embodiment, the tungsten layer 208 comprises tungsten or a tungsten alloy. However, the tungsten layer 208 may also comprise other metals, metal alloys, and dopants such as nickel, tin, titanium, tantalum, molybdenum, platinum, iron, niobium, palladium, nickel-cobalt alloy, doped cobalt, and combinations thereof. In an embodiment, tungsten and tungsten-containing materials are substantially pure tungsten or tungsten with no more than 5% impurities. In an embodiment, the tungsten layer 208 is a tungsten film or tungsten-containing film produced by CVD and / or ALD processes and may comprise pure tungsten (W), tungsten nitride (WN), tungsten carbide (WC), tungsten carbonitride (WCN), tungsten silicide (W k Si1) or tungsten oxide (W n O m ) film, where k, l, m, and n are integers with a range including 1 to 6. In an embodiment, the tungsten film may comprise tungsten with a nitride-containing metal or tungsten metal containing N or C. In an embodiment, the tungsten layer 208 comprises a tungsten product containing a nitride. Non-limiting examples of suitable tungsten products containing a nitride for use herein include tungsten nitride films (WN films), tungsten carbonitride films (WCN films), or tungsten nitride with a high nitrogen concentration (WNy, y > 0.1). In an embodiment, suitable tungsten films used in accordance with the present disclosure include tungsten, tungsten nitride with a low nitrogen concentration (WNx, 0 < x ≤ 0.1), tungsten carbide with a low carbon concentration (WCx, 0 < x ≤ 0.10), tungsten carbide with a high carbon concentration (WCy, y > 0.1), tungsten carbonitride with any carbon and nitrogen concentration (WCN).

[0028] In some embodiments, as Figure 2BAs shown, the tungsten layer 208 is deposited atop the surface 222 of the substrate 200 and within the trenches 202 formed in the surface 222. In an embodiment, the tungsten layer 208 is deposited within a plurality of trenches on the surface of the substrate. The tungsten layer 208 may be deposited using any suitable ALD and / or CVD deposition process. A non-limiting example of a CVD process suitable for depositing the tungsten layer 208 is disclosed in commonly owned U.S. Pat. No. 7,405,158, issued to Lai et al. on July 29, 2008, entitled “Method for Depositing a Tungsten Layer Using Atomic Layer Deposition Techniques.” In some embodiments, the tungsten layer 208 is deposited by a CVD process using a suitable tungsten precursor to form a tungsten-containing material, including an ALD process described in commonly owned U.S. Pat. No. 7,405,158, issued to Lai et al. on July 29, 2008, entitled “Method for Depositing a Tungsten Layer Using Atomic Layer Deposition Techniques” under the processing conditions disclosed therein. Suitable processing conditions for depositing the tungsten layer 208 include certain processing conditions, such as a temperature suitable for heating the substrate at a temperature in the range of from about 100° C. to about 600° C., or from about 200° C. to about 500° C., or from about 300° C. to about 450° C. In an embodiment, the processing chamber is maintained at a pressure in a range of from about 1 Torr to about 150 Torr, or a pressure in a range of from about 5 Torr to about 90 Torr.

[0029] In some embodiments, the thickness of the tungsten layer 208 is predetermined, such as from about 20 angstroms to about 150 angstroms, or from about 50 angstroms to about 150 angstroms. In some embodiments, the thickness of the tungsten layer 208 is predetermined, such as from about 5 angstroms to about 1000 angstroms, or from about 10 angstroms to about 500 angstroms, or from about 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100 angstroms. In an embodiment, the shape of the first tungsten layer 208 is substantially uniform and as shown in FIG. Figure 2B2 is conformal as shown generally in FIG. However, the inventors have observed that in the case of contact with air and oxygen, problematic changes may occur and oxidized material (e.g., filamentary defects) may form in the trench 202 adjacent to the bottom of the trench 202. As described above, filamentary defects may form in the lower portion (e.g., the lower half or lower third of the feature or trench), including WOx (where x is an integer) defects formed after tungsten or tungsten films (e.g., those formed by organic-based processes) are contacted with or exposed to air or oxygen. These defects may appear as filamentary deposits or residues that may compromise the conformality of the layer or appear as deposits that reduce the depth of the feature or trench compared to other features without defects. Defects such as filamentary defects are generally not observed in larger trenches, such as trenches with a width greater than 20 nanometers. Such defects are problematic for continuous processing such as deposition, patterning, and similar processes. As described herein, embodiments of the present disclosure reduce or eliminate these defects and ensure that the tungsten layer 208 remains substantially uniform and conformal after contact with air and / or oxygen. For example, in embodiments, when the first surface is in contact with oxygen, the tungsten layer 208 has a predetermined first thickness and is substantially uniform throughout the single trench and / or multiple trenches, such that the predetermined first thickness does not substantially change to a second thickness.

[0030] Reference Figure 1 , 2A 2B, embodiments of the present disclosure include a method 100 for reducing or eliminating defects in a tungsten film, including at 102: reducing or eliminating oxidation of a first surface 211 of a tungsten layer 208, such as a film having a predetermined first thickness 220 disposed on a substrate 200 and within a plurality of trenches 202. In an embodiment, the plurality of trenches (n) is an integer such as 1 or greater, representing a plurality of trenches in the substrate 200. In an embodiment, the plurality of trenches 202 may include a predetermined depth 207 and a width 209 less than 20 nanometers. In an embodiment, when the first surface 211 is in contact with oxygen, the predetermined first thickness 220 of the tungsten layer 208 is substantially uniform throughout the plurality of trenches 202, such that the predetermined first thickness 220 does not substantially change to a second thickness. For example, in an embodiment, when the first surface 211 is in contact with oxygen, the predetermined first thickness 220 of the tungsten layer 208 may be measured and determined to be substantially uniform throughout the plurality of trenches 202, such that the predetermined first thickness 220 does not substantially change to a second thickness. In one example, the predetermined first thickness 220 (shown as arrows in the tungsten layer 208) is approximately 150 angstroms and remains substantially uniform (approximately 150 angstroms) throughout the plurality of trenches 202 when the first surface 211 is in contact with oxygen, such that the predetermined first thickness 220 does not substantially change to the second thickness.

[0031] Reference Figure 1 ,Method 100 may include reducing or eliminating oxidation at 104 by contacting the first surface 211 with a reducing agent. In an embodiment, at 104, the first surface 211 is exposed to a soak process for a period ranging from about 1 second to about 90 seconds, such as 30 to 60 seconds, or about 60 seconds. In an embodiment, the soak process occurs under the same or substantially similar processing conditions, such as the temperature and pressure of a CVD or ALD process for depositing a tungsten layer. A pulse of a reducing agent or a reducing compound is introduced into the processing chamber along with a suitable carrier gas. The reducing gas may be the same compound as the gas used for the soak process, or alternatively, the reducing gas may be a different compound, depending on the product yield requirements and the device application. For example, in an embodiment where the first surface 211 is a tungsten film including a tungsten product containing nitride, a suitable reducing agent may include a halide-type metal precursor to provide a metal halide at the first surface 211. Non-limiting examples of suitable halide-type metal precursors include at least one of TiCl4, TaCl4, and combinations thereof. In other embodiments, the first surface 211 is a tungsten film including nitride, such as a tungsten nitride film (WN film), a tungsten carbonitride film (WCN film), or tungsten nitride with a high nitrogen concentration (WNy, y > 0.1), and a suitable reducing reagent may include a silane precursor, such as SiH4. In an embodiment, a silane precursor may be suitable where the tungsten film includes tungsten, tungsten nitride with a low nitrogen concentration (WNx, 0 < x ≤ 0.1), tungsten carbide with a low carbon concentration (WCx, 0 < x ≤ 0.10), tungsten carbide with a high carbon concentration (WCy, y > 0.1), tungsten carbonitride with any carbon and nitrogen concentration (WCN).

[0032] A purge gas may be introduced into the processing chamber to purge or otherwise remove any residual reducing compound.

[0033] Now referring to Figure 2C and Method 100 at 106, optionally, the first surface 211 may include a cover layer 230 disposed thereon to reduce or eliminate oxidation of the tungsten layer 208. In an embodiment, the shape of the cover layer 230 is substantially uniform and conformal, as Figure 2CAs shown generally in . In an embodiment, the capping layer 230 has conformal properties and does not completely fill the features or trenches. Therefore, the capping layer 230 can be shaped to accommodate additional layers disposed on top of the top surface of the capping layer. Suitable capping layers 230 may include metal or metal nitride materials, including titanium, titanium nitride, titanium silicon nitride, tantalum, tantalum nitride (TaN), tantalum silicon nitride, and combinations of the above materials. In an embodiment, the capping layer includes at least one of TiN, TaN, TiSiN, TiAlC, and combinations of the above materials. The capping layer 230 may be formed by processing techniques such as chemical vapor deposition (CVD), atomic layer deposition (ALD), physical vapor deposition (PVD), derivative depositions of the above depositions, and combinations of the above depositions. The capping layer 230 may be deposited to a thickness of at least about 30 angstroms, such as a thickness in the range of from about 30 angstroms to about 200 angstroms. In one example, the capping layer 230 is deposited on the first surface 211 by an ALD process using TiN. In another example, the capping layer 230 is deposited on the first surface 211 by an ALD process using TaN. In another example, the capping layer 230 is deposited on the first surface 211 by an ALD process using TiSiN. In another example, the capping layer 230 is deposited on the first surface 211 by an ALD process using TiAlC.

[0034] In an embodiment, the capping layer 230 may be plasma densified before performing subsequent manufacturing processes.

[0035] Figure 3 A schematic diagram of an illustrative apparatus of the type that may be used to practice embodiments of the present disclosure as discussed herein is depicted. Apparatus 300 may include a controller 350 and a process chamber 302 having an exhaust system 320 for removing excess process gases, process byproducts, or the like from an interior space 305 of process chamber 302. Exemplary process chambers may include any of several process chambers configured for thermal decomposition reactions, atomic layer deposition (ALD), or chemical vapor deposition (CVD), such chambers available from Applied Materials, Inc., Santa Clara, California. Other suitable process chambers from other manufacturers may similarly be used.

[0036] The processing chamber 302 has an interior space 305, which may include a processing space 304. The processing space 304 may be defined between, for example, a substrate support 308 disposed within the processing chamber 302, and one or more gas inlets, such as a showerhead 314 and / or nozzles disposed at predetermined locations, for example. In some embodiments, the substrate support 308 may include a mechanism for holding or supporting the substrate 310 on a surface of the substrate support 308, such as an electrostatic chuck, a vacuum chuck, a substrate holding clamp, or the like (not shown). In some embodiments, the substrate support 308 may include a mechanism for controlling the temperature of the substrate, such as a heating and / or cooling device (not shown), and / or for controlling species flux and / or ion energy near the substrate surface. In embodiments, the processing chamber 302 may be an oxygen-free processing chamber. In an embodiment, the substrate support 308 may include a filament 340 , a heating mechanism 336 , and a power source 338 sufficient to heat the substrate and facilitate deposition of a tungsten precursor in accordance with the present disclosure.

[0037] In some embodiments, the substrate support 308 may include an RF bias electrode (not shown). The RF bias electrode may be coupled to one or more bias power supplies (a bias power supply not shown) through one or more corresponding matching networks (matching networks shown). The one or more bias power supplies can generate up to 1200W or RF energy at a frequency of about 2MHz to about 60MHz, such as about 2MHz, or about 13.56MHz, or about 60MHz. In some embodiments, two bias power supplies may be provided for coupling RF power to the RF bias electrode at respective frequencies of about 2MHz and about 13.56MHz through respective matching networks. At least one bias power supply may provide continuous or pulsed power. In some embodiments, the bias power supply may optionally be a DC or pulsed DC source.

[0038] The substrate 310 may enter the processing chamber 302 via an opening 312 in a wall of the processing chamber 302. The opening 312 may be selectively sealed by a slit valve 318 or other mechanism to selectively provide access to the interior of the chamber through the opening 312. The substrate support 308 may be coupled to a lift mechanism 334 that may control the position of the substrate support 308 between a lower position (as shown) suitable for transferring substrates into and out of the chamber via the opening 312 and a selectable upper position suitable for processing. The processing position may be selected to maximize processing uniformity for a particular process. When in at least one of the elevated processing positions, the substrate support 308 may be disposed above the opening 312 to provide a symmetrical processing region.

[0039] One or more gas inlets (e.g., showerhead 314) may be coupled to a gas supply 316 for providing one or more process gases into the process volume 304 of the process chamber 302 via a mass flow controller 317. In addition, one or more valves 319 may be provided to control the flow of the one or more process gases. The mass flow controller 317 and the one or more valves 319 may be used alone or in combination to provide the process gas at a constant flow rate or a pulsed predetermined flow rate.

[0040] although Figure 3 A showerhead 314 is shown, however additional or alternative gas inlets may be provided, such as nozzles or inlets disposed in a ceiling or on a sidewall of the processing chamber 302, or nozzles or inlets disposed at other locations suitable for providing gas to the processing chamber 302, such as the base of the processing chamber, the periphery of a substrate support, or the like.

[0041] The apparatus 300 can utilize capacitively coupled RF energy for plasma processing. For example, the processing chamber 302 can have a top plate 342 made of a dielectric material and a showerhead 314 that is at least partially conductive to provide an RF electrode (or a separate RF electrode can be provided). The showerhead 314 (or other RF electrode) can be coupled to one or more RF power supplies (one RF power supply 348 is shown) through one or more corresponding matching networks (matching network 346 is shown). The one or more plasma sources can generate up to about 3000W of RF energy at a frequency of about 2MHz and / or about 13.56MHz or a high frequency (for example, 27MHz and / or 60MHz), or up to about 5000W of RF energy in some embodiments. The exhaust system 320 generally includes a pumping chamber 324 and one or more conduits that connect the pumping chamber 324 to the interior space 305 of the processing chamber 302 (and generally the processing space 304).

[0042] A vacuum pump 328 may be coupled to the pumping chamber 324 via a pumping port 326 for pumping exhaust gases from the processing chamber via one or more exhaust ports (two exhaust ports 322 are shown). The vacuum pump 328 may be fluidly connected to an exhaust port 332 for directing the exhaust to appropriate exhaust handling equipment. A valve 330 (e.g., a gate valve or similar valve) may be disposed in the pumping chamber 324 to facilitate controlling the flow of the exhaust gases in conjunction with the operation of the vacuum pump 328.

[0043] To facilitate control of the processing chamber 302 as described above, the controller 350 may be any form of general purpose computer processor that may be used in an industrial environment to control various chambers and subprocessors. The memory or computer readable medium 356 of the CPU 352 may be one or more of the following readily available memories such as random access memory (RAM), read only memory (ROM), floppy disk, hard disk, or any other form of local or remote digital storage. Support circuits 354 are coupled to the CPU 352 for supporting the processor in a conventional manner. These circuits include cache memory, power supplies, clock circuits, input / output circuits and subsystems, and the like.

[0044] The methods disclosed herein may generally be stored in the memory 356 as a software program 358, which, when executed by the CPU 352, causes the processing chamber 302 to perform the process of the present disclosure. The software program 358 may also be stored and / or executed by a second CPU (not shown), which is located at a remote location away from the hardware controlled by the CPU 352. Some or all of the methods of the present disclosure may also be executed in hardware. Thus, the present disclosure may be implemented in software and executed using a computer system, implemented in hardware (e.g., an application specific integrated circuit or other type of hardware implementation), or implemented in a combination of software and hardware. The software program 358 may be executed after the substrate 310 is positioned on the substrate support 308. When the software program 358 is executed by the CPU 352, the software program 358 transforms a general purpose computer into a special purpose computer (controller 150) that controls the operation of the chamber, so that the methods disclosed herein are performed.

[0045] Reference now Figure 4, a flow chart of a method 400 for depositing a tungsten film according to one embodiment of the present disclosure is shown. In process step 402, the method includes depositing a tungsten film having a first surface and a predetermined first thickness on a substrate and in a plurality of grooves, wherein the plurality of grooves include a predetermined depth and a width of less than 20 nanometers, and wherein when the first surface is in contact with oxygen, the predetermined first thickness is substantially uniform throughout the plurality of grooves, so that the predetermined first thickness does not substantially change to a second thickness. In an embodiment, depositing the tungsten film also includes contacting the first surface with a reducing agent. In an embodiment, the reducing agent is a halide-type metal precursor to provide a metal halide (e.g., TiCl4, TaCl4, and combinations thereof) or a silane precursor at the first surface, such as a silane precursor comprising SiH4, consisting essentially of SiH4, or consisting of SiH4. In an embodiment, the reducing agent is TiCl4, TaCl4, or a combination thereof in contact with the substrate, and the amount of the reducing agent is sufficient to reduce the substrate and / or prevent the formation of filamentary defects as described herein, or to form a tungsten layer having a varying, non-uniform thickness. In some embodiments, the tungsten film includes a tungsten product containing a nitride. In some embodiments, depositing the tungsten film further includes depositing a capping layer on the first surface.

[0046] Reference now Figure 5 , a flow chart of a method 500 for reducing or eliminating defects in a tungsten film is provided. In an embodiment, the method 500 includes depositing a tungsten film having a first surface and a predetermined first thickness on a substrate and in a plurality of grooves at 502, wherein the plurality of grooves include a predetermined depth and a width of less than 20 nanometers. At 504, the method 500 includes contacting the first surface with a halide-type metal precursor. At 506, the method 500 includes contacting the first surface with oxygen, wherein the predetermined first thickness does not substantially change to a second thickness when in contact with oxygen. In an embodiment, the halide-type metal precursor is one of TiCl4, TaCl4, or a combination thereof. In an embodiment, the halide-type metal precursor is provided to the interior space of the processing chamber in an amount sufficient to react with the first surface to reduce the first surface and / or prevent the formation of filamentary defects on the first surface as described herein, or to prevent the formation of a tungsten layer having a varying, non-uniform thickness when in contact with oxygen.

[0047] In an embodiment, the tungsten film includes a tungsten nitride-containing product, for example, the nitrogen-containing tungsten product may include, consist essentially of, or consist of a tungsten nitride film (WN film), a tungsten carbonitride film (WCN film), or a tungsten nitride with a high nitrogen concentration (WNy, y>0.1).

[0048] In some embodiments, the tungsten film comprises, consists essentially of, or consists of the following materials: tungsten, tungsten nitride with a low nitrogen concentration (WNx, 0 < x ≤ 0.1), tungsten carbide with a low carbon concentration (WCx, 0 < x ≤ 0.10), tungsten carbide with a high carbon concentration (WCy, y > 0.1), tungsten carbonitride with any carbon and nitrogen concentrations (WCN).

[0049] In other embodiments of the present disclosure, a method of depositing a tungsten film includes: depositing a tungsten film having a first surface and a predetermined first thickness on a substrate and within a plurality of features, wherein the plurality of features include a predetermined depth and a width less than 20 nanometers, and wherein when the first surface is contacted with oxygen, the predetermined first thickness remains substantially unchanged as a second thickness. In an embodiment, when the first surface is contacted with oxygen, the predetermined first thickness is substantially uniform throughout the plurality of features such that the predetermined first thickness remains substantially unchanged as a second thickness.

[0050] In other embodiments of the present disclosure, a method of depositing a tungsten film includes: depositing a tungsten film having a first surface and a predetermined first thickness on a substrate and within a plurality of features, wherein the plurality of features include a predetermined depth and a width less than 20 nanometers; reducing or eliminating oxidation of the first surface of the tungsten film by contacting the first surface with a halide-based metal precursor, silane, or a capping layer as described herein. In an embodiment, the method includes contacting the first surface with oxygen, wherein the predetermined first thickness remains substantially unchanged as a second thickness when contacted with oxygen.

[0051] Other semiconductor substrate processing systems may be used to practice the present disclosure, wherein those skilled in the art may adjust the processing parameters to achieve acceptable characteristics without departing from the spirit of the present disclosure by utilizing the teachings disclosed herein. Although the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the present disclosure may be designed without departing from the basic scope of the present disclosure.

Claims

1. A method for reducing or eliminating defects in a tungsten film, comprising: Reducing or eliminating oxidation of a first surface of a tungsten film having a predetermined first thickness provided on a substrate and within a plurality of trenches, wherein the plurality of trenches include trenches having an aspect ratio between 5:1 and 20:1, wherein the plurality of trenches include a predetermined depth and a width less than 20 nanometers, and wherein when the first surface is in contact with oxygen, throughout the plurality of trenches, the predetermined first thickness is substantially uniform, such that the predetermined first thickness does not substantially change to a second thickness, wherein the step of reducing or eliminating oxidation further includes contacting the first surface of the tungsten film with a reducing agent.

2. The method according to claim 1, wherein the reducing agent is a halide-type metal precursor to provide a metal halide at the first surface.

3. The method according to claim 2, wherein the halide-type metal precursor is at least one of TiCl4, TaCl4, and combinations thereof.

4. The method according to any one of claims 1-3, wherein the tungsten film comprises a tungsten product containing a nitride.

5. The method according to claim 4, wherein the tungsten product containing a nitride comprises a tungsten nitride film (WN film), a tungsten carbonitride film (WCN film), or tungsten nitride with a high nitrogen concentration (WNy, y > 0.1).

6. The method according to claim 1, wherein the reducing agent is a silane precursor.

7. The method according to claim 6, wherein the silane precursor comprises SiH4.

8. The method according to any one of claims 6 and 7, wherein the tungsten film comprises tungsten, tungsten nitride with a low nitrogen concentration (WNx, 0 < x ≤ 0.1), tungsten carbide with a low carbon concentration (WCx, 0 < x ≤ 0.10), tungsten carbide with a high carbon concentration (WCy, y > 0.1), tungsten carbonitride with any carbon and nitrogen concentration (WCN).

9. The method according to claim 1, wherein the step of reducing or eliminating oxidation further includes depositing a covering layer on the first surface.

10. The method according to claim 9, wherein the covering layer is TiN, TaN, TiSiN, TiAlC, or a combination of these materials.

11. The method according to claim 1, wherein the width of the plurality of trenches is between 5 and 10 nanometers.

12. A method for depositing a tungsten film, comprising: Depositing a tungsten film having a first surface and a predetermined first thickness on a substrate and within a plurality of trenches, wherein the plurality of trenches include trenches having an aspect ratio between 5:1 and 20:1, wherein the plurality of trenches include a predetermined depth and a width less than 20 nanometers, and wherein when the first surface is in contact with oxygen, throughout the plurality of trenches, the predetermined first thickness is substantially uniform, such that the predetermined first thickness does not substantially change to a second thickness, wherein the step of depositing the tungsten film further includes contacting the first surface of the tungsten film with a reducing agent.

13. The method according to claim 12, wherein the reducing agent is a halide-type metal precursor to provide a silane precursor or a metal halide at the first surface.

14. A method for reducing or eliminating defects in a tungsten film, comprising: depositing a tungsten film having a first surface and a predetermined first thickness on a substrate and within a plurality of trenches, wherein the plurality of trenches include a predetermined depth and a width less than 20 nanometers, and wherein the plurality of trenches include trenches having an aspect ratio between 5:1 and 20:1; contacting the first surface of the tungsten film with a halide-based metal precursor; and The first surface is contacted with oxygen, wherein the predetermined first thickness does not substantially change to a second thickness when contacted with oxygen.

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