Method for Selective Deposition of Tungsten onto a Dielectric Layer for Bottom-Up Gap Filling

Abstract

In one embodiment, the method includes depositing a tungsten layer via a PVD process onto a substrate region and onto sidewalls and a bottom dielectric surface of a feature disposed within the substrate to form a first tungsten portion having a first thickness on the region, a second tungsten portion having a second thickness on the sidewalls, and a third tungsten portion having a third thickness on the bottom surface, the second thickness being less than the first and third thicknesses; oxidizing a top surface of the tungsten layer to form a first tungsten oxide portion on the region, a second tungsten oxide portion on the sidewalls, and a third tungsten oxide portion on the bottom surface; removing the first, second, and third tungsten oxide portions, the second tungsten oxide portion being completely removed from the sidewalls; and passivating or completely removing the first tungsten portion from the region.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to a method for selective deposition of tungsten onto a dielectric layer.

Background Art

[0002] The size of the shape dimensions of semiconductor devices has been continuously decreasing. Therefore, semiconductor manufacturing equipment has produced devices with feature sizes less than 30 nm, and new equipment has been developed and implemented to produce devices with even smaller shape dimensions. As a result of the decreasing feature size, the spatial dimensions of the structural features on the device are also decreasing. The width of the gaps and trenches on the device has narrowed to the point where the aspect ratio of the depth and width of the gap becomes so large that it is difficult to fill the gap with a material. The deposited material tends to clog at the top before the gap is completely filled, creating voids or seams in the center of the gap.

[0003] Gap-fill deposition of tungsten films using chemical vapor deposition (CVD) techniques is an essential part of many semiconductor manufacturing processes. Tungsten films can be used as low-resistance electrical connections in the form of horizontal interconnects, vias between adjacent metal layers, and contacts between the first metal layer on a silicon substrate and the device. In conventional tungsten deposition processes, the wafer is heated to the process temperature in a vacuum chamber, and a tungsten film (bulk layer) is deposited onto the nucleation layer. The inventors have found that, regardless of the conformality of tungsten deposition in the CVD bulk layer, there is a problem that the formation of pockets trapped within the gap-fill tungsten by trenches may be promoted.

[0004] Physical vapor deposition (PVD) techniques are also known, but the inventors have observed that there remains a gap filling problem because the thickness of the tungsten film deposited by PVD can vary depending on whether the film deposits on the substrate region, the sidewalls of the features, or the bottom of the features. PVD tungsten deposition typically deposits a non-selective blanket material layer that is not useful as a substrate for subsequent selective deposition. The inventors have also observed that PVD deposition of tungsten is problematic even on non-conductive surfaces such as dielectric materials.

[0005] It is advantageous for a selective deposition process to be able to reduce the number and cost of steps associated with conventional lithography without lagging behind the shrinking rate of device dimensions. Since tungsten is an important material widely used to reduce the contact resistance of transistor connections, there is high potential value in selective deposition in a tungsten integration scheme. The inventors have observed that insufficient selectivity of tungsten materials between silicon and dielectrics, such as between silicon nitride and silicon oxide, causes serious problems in maximizing the filling of metal features. For example, as a result of insufficient selectivity, tungsten materials deposit on the sidewalls and bottoms of high aspect ratio features, limiting the ability to fill the features with the desired metal material. Since insufficient selectivity can exacerbate substrate non-uniformity, highly selective deposition of tungsten materials is required to reduce contact resistance and maximize the volume of feature filling materials.

[0006] Accordingly, the inventors have developed an improved method for the selective deposition of tungsten materials on dielectrics such as silicon oxide, silicon nitride, and tetraethyl orthosilicate (TEOS). SUMMARY OF THE INVENTION

[0007] Methods and apparatuses for selectively depositing a tungsten layer on a dielectric surface are provided herein. In some embodiments, a method for selectively depositing a tungsten layer on a dielectric surface includes: (a) depositing a tungsten layer via a physical vapor deposition (PVD) process on a substrate region and sidewalls of features disposed within the substrate and on a dielectric bottom surface to form a first tungsten portion having a first thickness on the substrate region, a second tungsten portion having a second thickness on the sidewalls, and a third tungsten portion having a third thickness on the dielectric bottom surface, wherein the second thickness is less than the first thickness and the third thickness; (b) oxidizing a top surface of the tungsten layer to form a first tungsten oxide portion on the substrate region, a second tungsten oxide portion on the sidewalls, and a third tungsten oxide portion on the dielectric bottom surface; (c) removing the first tungsten oxide portion, the second tungsten oxide portion, and the third tungsten oxide portion, wherein the second tungsten portion is completely removed from the sidewalls; and (d) stabilizing or completely removing the first tungsten portion from the substrate region. In embodiments, the first tungsten oxide portion on the substrate region is thicker than the third tungsten oxide portion on the dielectric bottom surface. In embodiments, selective tungsten growth is facilitated by maintaining the third tungsten portion or a portion of the third tungsten portion on the dielectric bottom surface.

[0008] In some embodiments, a method of selectively depositing a tungsten layer on a dielectric bottom surface includes: (a) depositing a tungsten layer via a physical vapor deposition (PVD) process on a substrate region, sidewalls of features disposed within the substrate, and the dielectric bottom surface to form a first tungsten portion having a first thickness on the substrate region, a second tungsten portion having a second thickness on the sidewalls, and a third tungsten portion having a third thickness on the dielectric bottom surface, wherein the second thickness is less than the first thickness and the third thickness; and (b) removing the first tungsten portion and the second tungsten portion such that the first tungsten portion and the second tungsten portion are completely removed from the substrate and the third tungsten portion remains on the dielectric bottom surface. In an embodiment, the first thickness is less than the third thickness.

[0009] In some embodiments, the present disclosure relates to a non-transitory computer-readable medium storing instructions that, when executed, cause a reaction chamber to selectively deposit a tungsten layer on a dielectric surface, wherein selectively depositing a tungsten layer on a dielectric surface includes: (a) depositing a tungsten layer via a physical vapor deposition (PVD) process on a substrate region, sidewalls of features disposed within the substrate, and the dielectric bottom surface to form a first tungsten portion having a first thickness on the substrate region, a second tungsten portion having a second thickness on the sidewalls, and a third tungsten portion having a third thickness on the dielectric bottom surface, wherein the second thickness is less than the first thickness and the third thickness; (b) oxidizing a top surface of the tungsten layer to form a first tungsten oxide portion on the substrate region, a second tungsten oxide portion on the sidewalls, and a third tungsten oxide portion on the dielectric bottom surface; (c) removing the first tungsten oxide portion, the second tungsten oxide portion, and the third tungsten oxide portion such that the second tungsten portion is completely removed from the sidewalls; and (d) stabilizing or completely removing the first tungsten portion from the substrate region.

[0010] In some embodiments, the present disclosure relates to a non-transitory computer-readable medium storing instructions that, when executed, cause a reaction chamber to selectively deposit a tungsten layer on a dielectric surface, where selectively depositing a tungsten layer on a dielectric surface includes: (a) depositing a tungsten layer via a physical vapor deposition (PVD) process on a substrate region, sidewalls of features disposed within the substrate, and a dielectric bottom surface to form a first tungsten portion having a first thickness on the substrate region, a second tungsten portion having a second thickness on the sidewalls, and a third tungsten portion having a third thickness on the dielectric bottom surface, wherein the second thickness is less than the first thickness and the third thickness; and (b) removing the first tungsten portion and the second tungsten portion such that the first tungsten portion and the second tungsten portion are completely removed from the substrate and the third tungsten portion remains on the dielectric bottom surface.

[0011] Further additional embodiments of the present disclosure are described below.

[0012] The embodiments of the present disclosure, briefly summarized above and discussed in more detail below, will be understood by reference to the exemplary embodiments of the present disclosure shown in the accompanying drawings. However, since the present disclosure may admit other equally effective embodiments, the accompanying drawings show only typical embodiments of the present disclosure and should not be regarded as limiting the scope.

Brief Description of the Drawings

[0013]

Figure 1

Figures 2A - 2B

Figures 2C - 2D

Figure 2E

Figures 3A - 3E

Figures 4A - 4D

Figures 5A - 5E

Figure 6

Figure 7

DETAILED DESCRIPTION OF THE INVENTION

[0014] For ease of understanding, the same reference numerals are used to refer to the same elements common to these figures, where possible. These figures are not drawn to scale and may be simplified for clarity. Even without further description, the elements and features of one embodiment can be beneficially incorporated into other embodiments.

[0015] The inventors have observed that according to the present disclosure, it is advantageous that tungsten deposited within a feature can be selectively formed directly above a dielectric layer. Selective deposition of tungsten directly above the dielectric layer provides bottom-up gap filling and is advantageous for reducing or eliminating the formation of voids or seams within the feature. By reducing or eliminating voids within the feature, the resistance is reduced, the yield of the device is increased, the manufacturing cost is reduced, and an increase in uniformity in multiple features during the formation of the semiconductor device is provided. The increased uniformity facilitates the application of additional process layers as the manufacturing continues.

[0016] FIG. 1 is a flow diagram of a method 100 for selectively depositing a tungsten layer on a dielectric surface according to some embodiments of the present disclosure. With respect to method 100, the steps of processing the substrate shown in FIGS. 2A-2E will be described below. The methods described herein can be provided in an independent configuration or as part of one or more cluster tools, such as an integrated tool 600 (i.e., a cluster tool) shown in FIG. 6, or a physical vapor deposition (PVD) chamber or etching chamber available from Applied Materials, Inc., Santa Clara, California, etc., and can be executed within individual processing chambers. Other processing chambers, including those available from other manufacturers, can also be adapted to benefit from the present disclosure.

[0017] Method 100 is typically executed on a substrate 200 provided in the processing volume of a processing chamber. In some embodiments, as shown in FIG. 2A, substrate 200 includes one or more features, such as a trench 210 (one is shown in FIGS. 2A-2E) to be selectively filled with tungsten layer 231, and trench 210 extends towards the base 214 of substrate 200. Although the following description is made with respect to one feature, substrate 200 can include any number of features (multiple trenches 210, vias, self-aligned vias, self-aligned contact features, dual damascene structures, etc.) described below, or can be suitable for use in multiple process applications such as dual damascene manufacturing processes, self-aligned contact feature processing, etc. Non-limiting examples of features suitable for etching according to the present disclosure include trenches, such as trench 210, vias, and dual damascene-type features.

[0018] In an embodiment, the substrate 200 can be formed from one or more of silicon (Si), silicon oxide, such as silicon monoxide (SiO) or silicon dioxide (SiO2), silicon nitride (SiN, etc.), or can include one or more of these. In a non-limiting embodiment, the substrate 200 can have a trench 210 formed in a dielectric layer, and thus the dielectric layer can be the substrate 200 or can be made from the same materials as those described above, such as SiN, SiO, etc. In an embodiment, a low dielectric constant dielectric material can be suitable as the substrate 200 or its layer (e.g., a material having a dielectric constant smaller than silicon oxide or smaller than about 3.9). Additionally, the substrate 200 can include additional material layers or can have one or more complete or partially complete structures or devices (not shown) formed in, on, or under the substrate 200. In an embodiment, the substrate 200 or one or more of its layers can include, for example, a doped or undoped silicon substrate, a III-V compound substrate, a silicon germanium (SiGe) substrate, an epi-substrate, a silicon-on-insulator (SOI) substrate, a display substrate, such as a liquid crystal display (LCD), a plasma display, an electroluminescence (EL) lamp display, a light-emitting diode (LED) substrate, a solar cell array, a solar panel, etc. In some embodiments, the substrate 200 includes a semiconductor wafer. In an embodiment, the material of the substrate 200 at the bottom of the trench 210 is a dielectric material and extends to the bottom of the trench 210.

[0019] In an embodiment, the substrate 200 is not limited to any size or shape. The substrate 200 can be, among other things, a circular wafer having a diameter of 200 mm, 300 mm, or other diameters, such as 450 mm. The substrate 200 can also be any polygon, square, rectangle, curved shape, or other non-circular workpiece, such as a polygonal glass substrate used in the manufacture of flat panel displays.

[0020] In some embodiments, features such as trenches 210 can be formed by etching the substrate 200 using any suitable etching process. In embodiments, features suitable for use in accordance with the present disclosure include one or more trenches having a depth-to-width aspect ratio greater than 1 and a width of less than 20 nanometers. In some embodiments, trench 210 is defined by substrate region 225, sidewalls 220 of the feature, such as trench 210, dielectric bottom surface 222, and upper corner 224 disposed within substrate 200. In some embodiments, trench 210 can have a high aspect ratio, such as an aspect ratio of from about 5:1 to about 20:1. As used herein, the aspect ratio is the ratio of the depth of the feature to the width of the feature. In embodiments, trench 210 has a width of 20 nanometers or less, a width indicated by arrow 226 of 10 nanometers or less, or a width indicated by arrow 226 of 5 to 10 nanometers.

[0021] Referring to FIG. 2B, in some embodiments, substrate 200 includes, or consists of, a dielectric layer of a material such as silicon oxide, silicon monoxide (SiO), silicon dioxide (SiO2), silicon nitride (such as SiN), tetraethyl orthosilicate (TEOS), etc., as described above, and has a shape having an opening 211 within substrate region 225, a surface opposite the opening 211 such as dielectric bottom surface 222, and sidewalls 220 between the opening 211 and the dielectric bottom surface 222, i.e., the surface opposite the opening 211.

[0022] Referring now to 102 of FIG. 1 and FIG. 2B, method 100 includes depositing a tungsten layer 231 via a physical vapor deposition (PVD) process on a substrate region 225, as well as on sidewalls 220 and dielectric bottom surfaces 222 of features such as trenches 210 disposed within substrate 200, to form a first tungsten portion having a first thickness on substrate region 225, a second tungsten portion having a second thickness on sidewalls 220, and a third tungsten portion having a third thickness on dielectric bottom surfaces 222, wherein the second thickness is less than the first thickness and the third thickness. For example, in some embodiments, tungsten layer 231 is deposited on substrate 200 and within features such as trench 210 in a processing chamber configured to PVD deposit tungsten layer 231. In an embodiment, tungsten layer 231 can be a layer non - conformally formed on substrate region 225 along sidewalls 220 and dielectric bottom surfaces 222 of features such as trench 210 such that most of the features prior to deposition of the layer remain unfilled after deposition of the layer, with a first tungsten portion (indicated by arrow 235) having a first thickness (indicated by arrow 236) disposed on or directly above substrate region 225, a second tungsten portion (adjacent to arrow 237) having a second thickness (indicated by arrow 238) disposed on or directly above sidewalls 220, and a third tungsten portion (shown above arrow 239) having a third thickness (indicated by arrow 240) disposed on or directly above dielectric bottom surfaces 222, and the second thickness (indicated by arrow 238) is less than the first thickness (indicated by arrow 236) and the third thickness (indicated by arrow 240). FIG. 2B is not drawn to scale. FIG. 2B is not drawn to scale, and in embodiments, the first thickness, the second thickness, and the third thickness are not equal.

[0023] In some embodiments, the tungsten layer 231 can be formed along the entire sidewalls 220, such as the two sidewalls of the trench 210, and the dielectric bottom surface 222. In some embodiments, the PVD chamber is configured to deposit a thinner tungsten layer on the sidewalls 220 than on the substrate region 225 or the dielectric bottom surface 222. For example, in some embodiments, the first tungsten portion (shown as arrow 235) has a first thickness (shown as arrow 236) in an amount of 3 - 6 nm, the second tungsten portion has a second thickness different from the first thickness, is disposed on the sidewalls 220, and the third tungsten portion (shown as arrow 2 39 as shown) has a third thickness (shown as arrow 240) in an amount of 3 - 6 nm. In an embodiment, the first thickness and the third thickness are thicker than the thickness of the second tungsten portion on the sidewalls 220. In an embodiment, the second tungsten portion has a second thickness of 0.5 - 1.5 nm, such as about 1 nm. In an embodiment, the first thickness is smaller than the third thickness. In an embodiment, the first thickness and the third thickness are each individually greater than the second thickness. In an embodiment, the first thickness is about 7 - 9 nm. In an embodiment, the second thickness is about 1 - 3 nm. In an embodiment, the third thickness is about 9 - 11 nm. In an embodiment, the first thickness is about 8 nm, the second thickness is about 2 nm, and the third thickness is about 10 nm.

[0024] In some embodiments, the thickness of the tungsten layer 231 is intended to fill the gaps within features such as trenches, vias, self-aligned vias, dual damascene structures. In an embodiment, the shape of the tungsten layer 231 partially fills the feature from the bottom of the feature adjacent to the dielectric bottom surface 222. In an embodiment, the feature is filled by about 5 - 25%, such as about 10%, 15%, or 20% on the dielectric bottom surface 222.

[0025] Referring further to FIG. 2B, a tungsten layer 231 PVD deposited within features such as trench 210 on substrate 200 is shown. In embodiments, tungsten layer 231 comprises tungsten or a tungsten alloy. However, in some embodiments, tungsten layer 231 can also include other metals, tungsten alloys and dopants such as nickel, tin, titanium, tantalum, molybdenum, platinum, iron, niobium, palladium, nickel cobalt alloys, doped cobalt, and combinations thereof. In embodiments, tungsten and tungsten-containing materials are substantially pure tungsten, or tungsten containing up to 1, 2, 3, 4, or 5% impurities.

[0026] In some embodiments, as shown in FIG. 2B, tungsten layer 231 is deposited within trench 210 formed in substrate 200 on dielectric bottom surface 222 of substrate 200. Tungsten layer 231 can be deposited using any PVD system available from Applied Materials, Inc., Santa Clara, Calif. Other suitable PVD processing chambers can be used as well. In some embodiments, suitable process conditions for PVD depositing tungsten layer 231 include process conditions such as a temperature suitable for heating the substrate within a range of about 450 degrees Celsius to about 600 degrees Celsius or within a range of about 450 degrees Celsius to about 500 degrees Celsius. In embodiments, the processing chamber for depositing tungsten is maintained at a pressure within a range of about 1 torr to about 150 torr or within a range of about 5 torr to about 90 torr.

[0027] Referring to 104 of FIG. 1, an embodiment of the present disclosure includes oxidizing the top surface 251 of the tungsten layer 231 to form a first tungsten oxide portion 254 on the substrate region, a second tungsten oxide portion 256 on the sidewall 220, and a third tungsten oxide portion 258 on the bottom surface of the dielectric. In an embodiment, plasma and oxygen are added under conditions sufficient to convert the tungsten in the first tungsten portion and the third tungsten portion partially to tungsten oxide (WOx) while converting the second tungsten portion on the sidewall 220 entirely to tungsten oxide. In an embodiment, the first tungsten portion (shown as arrow 235 in FIG. 2B) is partially converted to tungsten oxide from the top down, for example, over the length of the first tungsten portion, and the third tungsten portion (shown as arrow 2 39 shown as)) is partially converted to tungsten oxide from the top down, for example, over the length of the first portion, and the second tungsten portion on the sidewall 220 is entirely converted to tungsten oxide.

[0028] In some embodiments, the first tungsten portion (shown as arrow 235), the second tungsten portion (adjacent to arrow 237), and the third tungsten portion (shown as arrow 239) are each partially or fully oxidized by a radical oxidation process in which a sufficient amount of oxygen is provided to the substrate to contact the tungsten portions disposed on the substrate. In some embodiments, a sufficient amount of oxygen flux is provided to oxidize the second tungsten portion (adjacent to arrow 237) on the sidewall 220 to form tungsten oxide (WOx) on the surface of the substrate.

[0029] In some embodiments, the first tungsten oxide portion has a thickness of about 3 - 7 nm. In some embodiments, the second tungsten oxide portion has a thickness equal to the second thickness or the thickness of the second tungsten portion and can have a thickness such as about 1 - 3 nm. In some embodiments, the third tungsten oxide portion has a thickness of about 3 - 7 nm, for example, about 5, 6, or 7 nm.

[0030] In some embodiments, in a processing chamber, an oxidation process using oxygen radicals is performed on a substrate 200 having a first tungsten portion (shown as arrow 235), a second tungsten portion (adjacent to arrow 237), and a third tungsten portion (shown as arrow 239) to form the structure shown in FIG. 2C. In an embodiment, oxygen gas and argon gas are applied to the substrate. A plasma output is applied to these gases to generate oxygen radicals and the like. The radicals react with the substrate 200, as well as the first tungsten portion (shown as arrow 235), the second tungsten portion (adjacent to arrow 237 in FIG. 2B), and the third tungsten portion (shown as arrow 239 in FIG. 2B) to form oxide layers on the first tungsten portion, the second tungsten portion, and the third tungsten portion. In some embodiments, the oxidation process can be performed at an optimally controlled temperature. In an embodiment, the oxidation process can be performed at a temperature of about 200° Celsius to about 400° Celsius.

[0031] In some embodiments, a substrate 200 having a first tungsten portion (shown as arrow 235), a second tungsten portion (adjacent to arrow 237), and a third tungsten portion (shown as arrow 239) is loaded into the chamber. The pressure and temperature within the chamber are controlled to stabilize the chamber. To adjust the pressure within the chamber, an inert gas can be introduced into the chamber. The chamber has a temperature of about 200°C to about 400°C, or about 250°C to about 280°C. In some embodiments, a plasma output for generating plasma within the chamber is applied to the chamber. In an embodiment, the plasma output is in the range of about 1,000 W to about 5,000 W. In some embodiments, while the plasma output is continuously applied, a pressure suitable for the oxidation process is provided to the chamber. In some embodiments, the pressure is about 1 millitorr to 100 millitorr. In some embodiments, when the chamber is maintained under that pressure, oxygen gas is introduced into the chamber to perform a primary oxidation process. Additionally, an inert gas such as argon gas can be introduced into the chamber together with the oxygen gas. In an embodiment, argon gas is included and functions to rapidly generate plasma. In some embodiments, an oxygen gas flux sufficient to oxidize all of the tungsten disposed on the sidewall 220 of the tungsten layer pattern entirely and partially oxidize the first tungsten portion (shown as arrow 235) on the substrate region 225 and the third tungsten portion (shown as arrow 239) on the dielectric bottom surface 222 to form tungsten oxide (WOx, where x is equal to an integer) is provided. In an embodiment, the first tungsten portion (shown as arrow 235) and the third tungsten portion (shown as arrow 239) on the substrate region 225 are oxidized from the top down to a depth of 0.5 to 2.0 nm or about 1 to 1.5 nm.

[0032] Referring now to method 100 and process sequence 106 of FIGS. 2C and 2D, the present disclosure includes removing a first tungsten oxide portion (shown below arrow 261), a second tungsten oxide portion (shown adjacent to arrow 263), and a third tungsten oxide portion (shown adjacent to arrow 262), wherein the second tungsten oxide portion (shown adjacent to arrow 263) is completely removed from the sidewall. Accordingly, all tungsten on sidewall 220 is oxidized and all second tungsten oxide is removed, so that as shown in FIG. 2D, all tungsten is removed from sidewall 220. In embodiments, referring now to FIG. 2D, after performing the oxidation process, a reducing gas containing tungsten hexafluoride (WF6) is introduced in-situ into the chamber to reduce and remove tungsten oxide (WOx) on sidewall 220 of the tungsten layer pattern to form the structure shown in FIG. 2D that does not contain tungsten oxide on sidewall 220. In some embodiments, an amount of tungsten hexafluoride (WF6) sufficient to immerse the structure shown in FIG. 2D and remove all tungsten oxide from sidewall 220 is provided. As shown in FIG. 2D, at least a portion of the third tungsten portion remains on dielectric bottom surface 222 and at least a portion of the first tungsten portion remains on substrate region 225. In embodiments, examples of reducing gases can include hydrogen gas and NH3 gas. In embodiments, hydrogen gas and NH3 gas can be used alone or a mixture thereof can be used. In such embodiments, a reducing gas containing WF6 is used alone.

[0033] Referring now to method 100 and process sequence 108 of FIG. 2E, the present disclosure includes stabilizing the first tungsten portion from substrate region 225 or completely removing the first tungsten portion. For example, FIG. 2E shows stabilizing the first tungsten portion from substrate region 225 by forming a tungsten nitride layer 271 over or in the first tungsten portion 273 on substrate region 225. In embodiments, the tungsten nitride layer 271 is formed by a remote plasma reaction between nitrogen (N2), hydrogen (H2), and argon (Ar) at a first temperature of 300 to 400 degrees Celsius and a pressure of 50 millitorr to 1 torr in a processing chamber. In some embodiments, method 100 includes flowing reaction products from the remote plasma reaction into the processing chamber to selectively form a tungsten nitride layer 271 on the surface of the first tungsten portion 273. In embodiments, the top surface 280 of the third tungsten portion is not in contact with the remote plasma or the reactants of the remote plasma and does not react with nitrogen. In embodiments, nitrogen (N2) and argon (Ar) are reacted at a first temperature of 300 to 400 degrees Celsius by a remote plasma reaction. In some embodiments, about 65 watts of RF energy is applied to the remote plasma reaction. In embodiments, the tungsten nitride layer 271 is deposited to an intended thickness such as from about 10 angstroms to about 100 angstroms or from about 100 to about 500 angstroms.

[0034] In some embodiments, nitrogen is provided at a flow rate of about 5 sccm or less in process sequence 108 or in the nitridation process sequence of the direct plasma reaction. In an embodiment, the pressure in the processing chamber during the direct plasma reaction is maintained between 50 millitorr and 1 torr. In an embodiment, RF power of about 100 watts to 1000 watts is applied during the direct plasma reaction. In an embodiment, the nitridation process is characterized by a weak nitrogen-based plasma that provides little nitrogen to the structure shown in FIG. 2D, and thus only the top surface of the tungsten disposed on the substrate region 225 reacts with the nitrogen plasma. In an embodiment, after the stabilization treatment or removal of the first tungsten portion, only the third tungsten portion 274 remains available for selective deposition in the downstream processing of the substrate 200.

[0035] Figures 3A-3E each show a stage of selectively depositing a tungsten layer on a dielectric surface according to an embodiment of the present disclosure. For example, in some embodiments, the present disclosure relates to a method of selectively depositing a tungsten layer on a dielectric surface, the method comprising depositing a tungsten layer via a physical vapor deposition (PVD) process on a substrate region and sidewalls of features disposed within the substrate and on a dielectric bottom surface to form a first tungsten portion having a first thickness on the substrate region, a second tungsten portion having a second thickness on the sidewalls, and a third tungsten portion having a third thickness on the dielectric bottom surface, the second thickness being less than the first thickness and the third thickness; oxidizing the top surface of the tungsten layer to form a first tungsten oxide portion on the substrate region, a second tungsten oxide portion on the sidewalls, and a third tungsten oxide portion on the dielectric bottom surface; removing the first tungsten oxide portion, the second tungsten oxide portion, and the third tungsten oxide portion, wherein the second tungsten portion is completely removed from the sidewalls; and removing the first tungsten portion from the substrate region.

[0036] FIG. 3A shows a substrate 200 including the embodiment described above in FIG. 2A. FIG. 3B shows a tungsten layer 231 that is PVD deposited on the substrate region 225, as well as on sidewalls 220 and dielectric bottom surface 222 of features such as trench 210 disposed within the substrate 200, to form a first tungsten portion 291 having a first thickness on the substrate region 225, a second tungsten portion 292 having a second thickness on the sidewalls 220, and a third tungsten portion 293 having a third thickness on the dielectric bottom surface 222. In an embodiment, the second thickness is less than the first thickness and the third thickness.

[0037] Referring to FIG. 3C, embodiments of the present disclosure include oxidizing the top surface 251 of the tungsten layer 231 to form a first tungsten oxide portion 254 on the substrate region, a second tungsten oxide portion 256 on the sidewalls 220, and a third tungsten oxide portion 258 on the dielectric bottom surface or tungsten deposited on the dielectric bottom surface. In an embodiment, plasma and oxygen are added under conditions sufficient to convert the tungsten in the first tungsten portion and the third tungsten portion to tungsten oxide partially while converting the tungsten portion on the sidewalls 220 to tungsten oxide entirely. In an embodiment, the first tungsten portion is converted to tungsten oxide more than the third tungsten portion. In an embodiment, the present disclosure includes restricting the thickness of the third tungsten oxide portion 258 on the dielectric bottom surface 222 or the tungsten 299 deposited on the dielectric bottom surface 222 while preselecting or adjusting the thickness of the first tungsten oxide portion 254.

[0038] In some embodiments, the degree or thickness of tungsten oxidation can be controlled by dissociation and plasma characteristics to adjust tungsten oxidation to provide improved etching performance. For example, in some embodiments that include a low-power capacitively coupled plasma (CCP) in a processing chamber containing substrate 200, chamber degradation can be reduced, thereby providing an improved process. Accordingly, the systems described herein provide improved etching performance while providing improved flexibility with respect to the adjustment of chemical properties. In an embodiment, a non-limiting processing chamber suitable for etching according to the present disclosure is illustrated and described in U.S. Patent No. 9,362,130, entitled "Enhanced Etching Processes Using Remote Plasma Sources" by Ingle et al., issued on June 7, 2016, and assigned to Applied Materials, Inc. In some embodiments, the processing chamber for use herein is coupled to a remote plasma source that provides gas processing radicals to the processing volume. Typically, the remote plasma source (RPS) includes a capacitively coupled plasma (CCP) source. In some embodiments, the remote plasma source is a standalone RPS unit. In other embodiments, the remote plasma source is a second processing chamber that is in fluid communication with the processing chamber containing substrate 200.

[0039] In some embodiments, the remote plasma region within a processing chamber, such as an etching chamber, can be configured for capacitively coupled plasma (``CCP'') formed within the region of the processing chamber. In an embodiment, the plasma configuration within the remote plasma region can be fluidly disposed, for example, between another remote plasma region and a processing region. In some embodiments, the remote plasma region can be defined by two or more electrodes that enable formation of plasma within that region. In some embodiments, since the CCP can be utilized not to completely ionize the species within the plasma region but only to maintain the oxygen-containing plasma emissions, the CCP can be operated at a reduced or substantially reduced power. For example, the CCP can be operated at power levels such as about 400W, 250W, 200W, 150W, 100W, 50W, 20W or less. Further, the CCP can produce a flat plasma profile, thereby providing a uniform plasma distribution within the space. Accordingly, a more uniform plasma can be delivered to the first tungsten portion 291 and the second tungsten portion 292 and not reach the third tungsten portion 293. Correspondingly, compared with the third tungsten portion 293, the first tungsten portion 291 can be oxidized more, or a thicker tungsten oxide layer can be formed by the first tungsten portion 291. In an embodiment, the second tungsten portion 292 is thin and thus is entirely converted to tungsten oxide.

[0040] In some embodiments, an oxygen-containing plasma such as CCP can be delivered at a power of less than 400W, for example, 350W to 375W. In some embodiments, the CCP oxygen-containing plasma can be delivered at a temperature of about 300 degrees Celsius to about 400 degrees Celsius. In some embodiments, the CCP oxygen-containing plasma can be delivered with oxygen provided at a flow rate of less than 50 sccm, for example, 30 to 45 sccm. In an embodiment, the CCP oxygen-containing plasma can be delivered in less than 60 seconds, less than 30 seconds, or 10 to 25 seconds.

[0041] Referring to FIG. 3D, the present disclosure includes removing a first tungsten oxide portion 254, a second tungsten oxide portion 256, and a third tungsten oxide portion 258, and the second tungsten portion 292 is completely removed from the sidewall 220. In embodiments, as described above, tungsten oxide is contacted and immersed in tungsten hexafluoride (WF6). For example, referring next to FIG. 3D, after performing an oxidation process, a reducing gas containing tungsten hexafluoride (WF6) is introduced in-situ into the processing chamber containing the substrate 200 to reduce and remove tungsten oxide (WOx) on the sidewall 220 of the tungsten layer pattern, forming the structure shown in FIG. 3D that does not contain tungsten oxide on the sidewall 220. In some embodiments, an amount of tungsten hexafluoride (WF6) sufficient to immerse the structure shown in FIG. 3D and remove all of the tungsten oxide from the sidewall 220 is provided. In some embodiments, as indicated by arrows 297 and 298, (a) oxidizing the top surface of the tungsten layer to form a first tungsten oxide portion on the substrate region, a second tungsten oxide portion on the sidewall, and a third tungsten oxide portion on the dielectric bottom surface; and (b) removing the first tungsten oxide portion, the second tungsten oxide portion, and the third tungsten oxide portion, wherein the second tungsten portion is completely removed from the sidewall. The process sequence including removing is repeated to adjust the oxidation and removal of tungsten. In embodiments, the process sequences (a) and (b) can be repeated for a sufficient number of cycles to remove all of the first tungsten portion 291 and form the structure shown in FIG. 3E, with only the third tungsten portion 293 remaining deposited on or directly above the dielectric material of the substrate 200. In embodiments, the process sequences (a) and (b) can be repeated 1 to 10 times or 1 to 5 times to remove the first tungsten portion 291 and form the structure shown in FIG. 3E.

[0042] FIG. 7 is a flow diagram of a method 700 for selectively depositing a tungsten layer on a dielectric surface according to some embodiments of the present disclosure. With respect to method 700, the steps of processing the substrate shown in FIGS. 4A-4D will be described below. The methods described herein can be provided in a stand-alone configuration or as part of one or more cluster tools, such as an integrated tool 600 (i.e., a cluster tool) shown in FIG. 6, or available from Applied Materials, Inc., Santa Clara, California, and can be executed within an individual processing chamber, such as a physical vapor deposition (PVD) chamber or an etching chamber. Other processing chambers, including those available from other manufacturers, can also be adapted to benefit from the present disclosure.

[0043] FIGS. 4A-4D each show a step of selectively depositing a tungsten layer on a dielectric surface according to an embodiment of the present disclosure. For example, in some embodiments, the present disclosure relates to a method of selectively depositing a tungsten layer on a dielectric surface, the method comprising depositing a tungsten layer via a physical vapor deposition (PVD) process on a substrate region and sidewalls of features disposed within the substrate and on a dielectric bottom surface, as shown in process sequence 702, to form a first tungsten portion having a first thickness on the substrate region, a second tungsten portion having a second thickness on the sidewalls, and a third tungsten portion having a third thickness on the dielectric bottom surface, wherein the second thickness is less than the first thickness and the third thickness; and removing the first tungsten portion and the second tungsten portion, as shown in process sequence 704, wherein the first tungsten portion and the second tungsten portion are completely removed from the substrate and the third tungsten portion remains on the dielectric bottom surface.

[0044] FIG. 4A shows a substrate 200 including the embodiment described above in FIG. 2A. FIG. 4B shows a tungsten layer 231 that is PVD deposited on the substrate region 225, as well as on the sidewalls 220 of features such as the trench 210 disposed within the substrate 200 and on the dielectric bottom surface 222 to form a first tungsten portion 291 having a first thickness on the substrate region 225, a second tungsten portion 292 having a second thickness on the sidewalls 220, and a third tungsten portion 293 having a third thickness on the dielectric bottom surface 222. In an embodiment, the second thickness is less than the first thickness and the third thickness. The PVD reaction conditions, as well as the thicknesses such as the first thickness, the second thickness, and the third thickness, can be the same as those described above.

[0045] Referring to FIGS. 4B and 4C, embodiments of the present disclosure include removing a first tungsten portion 291 and a second tungsten portion 292, and the second tungsten portion 292 is completely removed from the sidewall 220. In some embodiments, the tungsten etch-back of the first tungsten portion 291 and the second tungsten portion 292 uses a tungsten halide plasma (e.g., WF6 plasma) and is achieved by contacting the first tungsten portion 291 and the second tungsten portion 292 with the tungsten halide plasma under conditions sufficient to partially or completely etch or remove the first tungsten portion 291 and the second tungsten portion 292. In an embodiment, the substrate 200 is disposed in a processing chamber including a suitable plasma source such as a radio frequency (RF) or remote plasma source (RPS). In some embodiments, atomic fluorine is dissociated from the WF6 plasma and this atomic fluorine is used to etch the metallic tungsten of at least the first tungsten portion 291 and the second tungsten portion 292. In an embodiment, the etch rate depends on the flow of WF6 and the plasma conditions. By adjusting the process conditions, a very moderate etch rate in the range of 0.5 angstroms / second to 3 angstroms / second can be achieved to control the amount of etch-back. In an embodiment, since WF6 can be used as both a deposition precursor and an etchant in the chamber, an etch-deposition process of single-chamber deposition can be realized. A standard PVD chamber having RF or RPS plasma capabilities can perform both deposition and etch-back, thus providing improved throughput and chamber redundancy.

[0046] In some embodiments, the first tungsten portion 291 and the second tungsten portion 292 are etched using a tungsten-containing gas to remove some portions of the first tungsten portion 291 and the second tungsten portion 292. The etching process (also known as an etch-back process) removes some portions of the first tungsten portion 291 and the second tungsten portion 292 along the sidewalls 220. The etching process can also be performed in the same processing chamber as the tungsten deposition process. In an embodiment, a plasma can be formed by coupling high-frequency (RF) power to a process gas such as helium (He), argon (Ar), oxygen (O2), nitrogen (N2), or a combination thereof. The plasma can be formed by a remote plasma source (RPS) and delivered to the processing chamber.

[0047] In an embodiment, during the etching process, the temperature of the substrate 200 can be in the range of about 100 degrees Celsius to about 600 degrees Celsius (e.g., in the range of about 300 degrees Celsius to 430 degrees Celsius). In an embodiment, the etching of the first tungsten portion 291 and the second tungsten portion 292 can be performed while the pressure in the processing chamber is in the range of about 0.1 torr to about 5 torr (e.g., in the range of about 0.5 torr to about 2 torr). In one example, the pressure can be about 1 torr. In an embodiment, a process gas (e.g., argon (Ar)) can be introduced at a flow rate in the range of about 100 sccm to about 3,000 sccm. In one example, argon can be introduced at a total flow rate of 2,000 sccm. In an embodiment, the tungsten-containing compound for etching can be tungsten hexafluoride (WF6) and can be introduced at a continuous flow rate in the range of about 1 sccm to 150 sccm, e.g., in the range of about 3 sccm to 100 sccm.

[0048] In an embodiment, after the etch back described in this specification, after removing the first tungsten portion 291 and the second tungsten portion 292 or some portions thereof, the substrate 200 can be further processed to form the structure shown in FIG. 4D. For example, in some embodiments, an amount of tungsten hexafluoride (WF6) sufficient to immerse the structure shown in FIG. 4C and remove all of the tungsten oxide from the sidewalls 220 is provided. As shown in FIGS. 4C and 4D, at least a portion of the third tungsten portion 293 remains on the dielectric bottom surface 222, and no tungsten remains on the substrate region 225 and the sidewalls 220. In an embodiment, examples of the reducing gas can include hydrogen gas and NH3 gas. In an embodiment, hydrogen gas and NH3 gas can be used alone, or a mixture thereof can be used. In such an embodiment, the reducing gas containing WF6 is used alone.

[0049] FIGS. 5A - 5E respectively show the steps of selectively depositing a tungsten layer on a dielectric surface according to an embodiment of the present disclosure. For example, in some embodiments, the present disclosure relates to a method of selectively depositing a tungsten layer on a dielectric surface, the method comprising depositing a tungsten layer via a physical vapor deposition (PVD) process on a substrate region and sidewalls and a dielectric bottom surface of features disposed within the substrate to form a first tungsten portion having a first thickness on the substrate region, a second tungsten portion having a second thickness on the sidewalls, and a third tungsten portion having a third thickness on the dielectric bottom surface, wherein the second thickness is smaller than the first thickness and the third thickness; oxidizing the top surface of the tungsten layer to form a first tungsten oxide portion on the substrate region, a second tungsten oxide portion on the sidewalls, and a third tungsten oxide portion on the dielectric bottom surface; removing the first tungsten oxide portion, the second tungsten oxide portion, and the third tungsten oxide portion, wherein the second tungsten portion is completely removed from the sidewalls; and removing the first tungsten portion from the substrate region.

[0050] FIG. 5A shows a substrate 200 including the embodiment described above in FIG. 2A. FIG. 5B shows a tungsten layer 231 PVD deposited on the substrate region 225, as well as on sidewalls 220 of features such as trench 210 disposed within substrate 200 and on dielectric bottom surface 222 to form a first tungsten portion 291 having a first thickness on the substrate region 225, a second tungsten portion 292 having a second thickness on sidewalls 220, and a third tungsten portion 293 having a third thickness on dielectric bottom surface 222. In an embodiment, the second thickness is less than the first thickness and the third thickness.

[0051] In an embodiment, the PVD chamber is the chamber disclosed in U.S. Patent No. 9,062,372 entitled "Self-Ionized and Capacitively-Coupled Plasma For Sputtering and Resputtering" by Gopalraja et al., assigned to Applied Materials. In an embodiment, a suitable processing chamber sputterer is configured to deposit tungsten by self-ionized plasma (SIP) sputtering.

[0052] In an embodiment, the PVD deposition is performed by sputter depositing tungsten by self-ionized plasma (SIP) sputtering. In an embodiment, a magnetic field generated by an electromagnetic coil confines the capacitively-coupled generated plasma, increasing the plasma density and thus the ionization rate. Long-distance sputtering is characterized by a relatively large ratio of the distance between the target and the substrate to the diameter of the substrate. Long-distance SIP sputtering facilitates the coating of deep holes with both ionized and neutral deposited material components. By CCP re-sputtering, the thickness of the effective range at the bottom of the deep hole layer can be reduced, reducing the contact resistance.

[0053] In embodiments, SIP tends to be promoted by a low pressure of less than 5 millitorr. In particular, SIP at particularly low pressures tends to be promoted by a magnetron having a relatively small area and increasing the target power density, and a magnetron having an asymmetric magnet that allows the magnetic field to penetrate further towards the substrate. According to one aspect of the present disclosure, plasma conditions are provided for depositing a target material by SIP sputtering.

[0054] In embodiments, a reactor is provided that includes a DC magnetron-type reactor based on a modified form of an Endura PVD Reactor available from Applied Materials, Inc. of Santa Clara, California. In embodiments, the reactor is capable of self-ionized sputtering (SIP) in long-distance mode. In one embodiment, an SIP mode can be used where a non-uniform effective range is desired, such as an effective range mainly induced on the sidewalls of the holes. An SIP mode can be used to achieve a more uniform effective range. In yet another alternative embodiment, the pressure in the chamber can be varied step by step. For example, the pressure can be increased during SIP sputtering.

[0055] To attract ions generated by the plasma, a negative bias can be applied to the tungsten target with a DC power of 1 to 40 kW, for example, by a variable DC power supply. The power supply applies a negative bias of about -400 to -600 VDC to the target with respect to the chamber shield to ignite and maintain the plasma. Generally, a voltage of less than -1000 VDC is suitable for use herein. Typically, 1 to 5 kW of target power is used to ignite the plasma, and a power greater than 10 kW is suitable for the SIP sputtering described herein. For example, tungsten can be deposited by SIP sputtering using 24 kW of target power.

[0056] In an embodiment, the power supply can apply RF power to the pedestal electrode to bias the substrate and attract deposited material ions during SIP sputter deposition. During SIP deposition, the pedestal, and thus the substrate 200, can be left electrically floating, yet still a negative DC self-bias can be generated on the pedestal, and thus on the substrate 200. Alternatively, the power supply can apply a negative bias to the pedestal at -30 VDC to bias the substrate negatively and attract the ionized deposited material to the substrate.

[0057] In some embodiments, when argon is passed through the PVD processing chamber, the DC voltage difference between a target, such as a tungsten target, and the chamber shield can ignite the argon into a plasma, and the positively charged argon ions are attracted to the negatively charged target. These ions strike the target with considerable energy, sputtering target atoms or atom clusters from the target. Some of the target particles strike the substrate 200 and are deposited on the substrate 200 to form a PVD-deposited tungsten material layer as shown in FIG. 5B. In the reactive sputtering of the tungsten material, tungsten is deposited to form a first tungsten portion 291 having a first thickness on the substrate region 225, a second tungsten portion 292 having a second thickness on the sidewall 220, and a third tungsten portion 293 having a third thickness on the dielectric bottom surface 222. In an embodiment, the second thickness is smaller than the first thickness and the third thickness. In an embodiment, the third thickness is thicker than the first thickness and the second thickness. In some embodiments, the first thickness is about 7 - 9 nm. In some embodiments, the second thickness is about 1 - 3 nm. In some embodiments, the third thickness is about 9 - 11 nm. In some embodiments, the first thickness is about 8 nm, the second thickness is about 2 nm, and the third thickness is about 10 nm.

[0058] Referring to FIG. 5C, an embodiment of the present disclosure includes oxidizing the top surface 251 of the tungsten layer 231 or the top surface of the first tungsten portion 291 having a first thickness, the top surface of the second tungsten portion 292 having a second thickness on the sidewall 220, and the top surface of the third tungsten portion 293 to form a first tungsten oxide portion 254 on the substrate region, a second tungsten oxide portion 256 on the sidewall 220, and a third tungsten oxide portion 258 on the dielectric bottom surface or tungsten deposited on the dielectric bottom surface. In an embodiment, plasma and oxygen are applied under conditions sufficient to convert the tungsten in the first and third portions entirely to tungsten oxide while partially converting the tungsten on the sidewall 220 to tungsten oxide. In an embodiment, the first tungsten portion is converted to tungsten oxide more than the third tungsten portion. In an embodiment, the present disclosure includes limiting the thickness of the third tungsten oxide portion 258 on the dielectric bottom surface or tungsten deposited on the dielectric bottom surface while preselecting or adjusting the thickness of the first tungsten oxide portion 254.

[0059] In an embodiment, after forming the first tungsten oxide portion 254 on the substrate region, the second tungsten oxide portion 256 on the sidewall 220, and the third tungsten oxide portion 258 on the dielectric bottom surface or tungsten deposited on the dielectric bottom, the substrate 200 can be further processed to form the structure shown in FIG. 5E. For example, in some embodiments, an amount of tungsten hexafluoride (WF6) sufficient to immerse the structure shown in FIG. 5C and remove all of the tungsten oxide from the sidewall 220 is provided. As shown in FIGS. 5C and 5D, at least a portion of the third tungsten portion 293 remains on the dielectric bottom surface 222. After further etching, as shown in FIG. 5E, no tungsten remains on the substrate region 225 and the sidewall 220. In an embodiment, examples of the reducing gas can include hydrogen gas and NH3 gas. In an embodiment, hydrogen gas and NH3 gas can be used alone or a mixture thereof can be used. In such embodiments, the reducing gas containing WF6 is used alone.

[0060] The tungsten-containing layer exhibits usefulness when the tungsten layer described above is integrated by a conventional filling technique to form a feature having excellent film characteristics. The integration method for depositing the tungsten layer can include physical vapor deposition (PVD) and plasma enhancement. An etching chamber is also suitable for use herein. Integrated processing systems capable of performing the integrated methods disclosed herein include ENDURA®, ENDURA® SL, CENTURA®, or PRODUCER® processing systems, each available from Applied Materials, Inc. of Santa Clara, California. In one implementation, physical vapor deposition (PVD) and an etching chamber can be provided to perform all vapor deposition and etching processes associated with the tungsten layer on the dielectric layer.

[0061] Referring now to FIG. 6, the method described herein can be performed in an individual processing chamber provided in an independent configuration or as part of one or more cluster tools, such as the integrated tool 600 (i.e., cluster tool) described below with respect to FIG. 6. In an embodiment, the cluster tool is configured to perform a method such as method 100 for selectively depositing a tungsten layer on a dielectric surface, the method comprising: (a) depositing a tungsten layer via a physical vapor deposition (PVD) process on a substrate region and sidewalls of features disposed within the substrate and on a dielectric bottom surface to form a first tungsten portion having a first thickness on the substrate region, a second tungsten portion having a second thickness on the sidewalls, and a third tungsten portion having a third thickness on the dielectric bottom surface, wherein the second thickness is less than the first and third thicknesses; (b) oxidizing the top surface of the tungsten layer to form a first tungsten oxide portion on the substrate region, a second tungsten oxide portion on the sidewalls, and a third tungsten oxide portion on the dielectric bottom surface; (c) removing the first tungsten oxide portion, the second tungsten oxide portion, and the third tungsten oxide portion, wherein the second tungsten portion is completely removed from the sidewalls; and (d) stabilizing or completely removing the first tungsten portion from the substrate region.

[0062] In an embodiment, the cluster tool can be configured to include additional chambers. Non-limiting examples of additional chambers for selective metal deposition include VOLTA™ brand processing chambers available from Applied Materials, Inc. of Santa Clara, California. Examples of integrated tools 600 include CENTURA™ and ENDURA™ integrated tools available from Applied Materials, Inc. of Santa Clara, California. However, the methods described herein can be implemented using other cluster tools with suitable processing chambers attached, or other cluster tools within other suitable processing chambers. For example, in some embodiments, it is advantageous that the method of the invention discussed above can be performed within an integrated tool such that the vacuum break during processing is limited or non-existent.

[0063] In an embodiment, the integrated tool 600 can include two load lock chambers 606A, 606B for transferring substrates to and from the interior and exterior of the integrated tool 600. Typically, since the integrated tool 600 is under vacuum, the load lock chambers 606A, 606B can "pump down" the substrates introduced into the integrated tool 600. A first robot 410 can transfer substrates between the load lock chambers 606A, 606B and a first set of one or more substrate processing chambers 612, 614, 616, 618 (shown as four) coupled to a first central transfer chamber 650. Each substrate processing chamber 612, 614, 616, 618 can be equipped to perform a plurality of substrate processing operations. In some embodiments, the first set of one or more substrate processing chambers 612, 614, 616, 618 can include any combination of PVD, etching, ALD, CVD, or degassing chambers. For example, in some embodiments, the substrate processing chambers 612 and 614 include processing chambers suitable for PVD deposition configured to deposit tungsten on the substrate as described above.

[0064] In some embodiments, the first robot 610 can also transfer substrates between two intermediate transfer chambers 622, 624. The intermediate transfer chambers 622, 624 can be used to enable the transfer of substrates within the integrated tool 600 while maintaining ultra-high vacuum conditions. A second robot 630 can transfer substrates between the intermediate transfer chambers 622, 624 and one or more substrate processing chambers 632, 634, 635, 636, 638 of a second set coupled to a second central transfer chamber 655. The substrate processing chambers 632, 634, 635, 636, 638 can be equipped to perform various substrate processing operations including the methods 300, 400 described above, in addition to physical vapor deposition processes (PVD), chemical vapor deposition (CVD), selective metal deposition, etching, orientation, and other substrate processes. Any of the substrate processing chambers 612, 614, 616, 618, 632, 634, 635, 636, 638 can be removed from the integrated tool 600 if not needed to perform a particular process by the integrated tool 600. In an embodiment, the microprocessor, when executed, includes memory such as a non-transitory computer-readable medium storing instructions that cause the integrated tool or reaction chamber to deposit a tungsten layer selectively on a dielectric surface according to the present disclosure.

[0065] In some embodiments, the present disclosure relates to a non-transitory computer-readable medium storing instructions that, when executed, cause a reaction chamber to selectively deposit a tungsten layer on a dielectric surface, and selectively depositing a tungsten layer on the dielectric surface includes: (a) depositing a tungsten layer via a physical vapor deposition (PVD) process on a substrate region, sidewalls of features disposed within the substrate, and a dielectric bottom surface to form a first tungsten portion having a first thickness on the substrate region, a second tungsten portion having a second thickness on the sidewalls, and a third tungsten portion having a third thickness on the dielectric bottom surface, wherein the second thickness is less than the first thickness and the third thickness; (b) oxidizing a top surface of the tungsten layer to form a first tungsten oxide portion on the substrate region, a second tungsten oxide portion on the sidewalls, and a third tungsten oxide portion on the dielectric bottom surface; (c) removing the first tungsten oxide portion, the second tungsten oxide portion, and the third tungsten oxide portion, wherein the second tungsten portion is completely removed from the sidewalls; and (d) stabilizing or completely removing the first tungsten portion from the substrate region.

[0066] In some embodiments, the present disclosure relates to a non-transitory computer-readable medium storing instructions that, when executed, cause a reaction chamber to selectively deposit a tungsten layer on a dielectric surface, and selectively depositing a tungsten layer on the dielectric surface includes: (a) depositing a tungsten layer via a physical vapor deposition (PVD) process on a substrate region, sidewalls of features disposed within the substrate, and a dielectric bottom surface to form a first tungsten portion having a first thickness on the substrate region, a second tungsten portion having a second thickness on the sidewalls, and a third tungsten portion having a third thickness on the dielectric bottom surface, wherein the second thickness is less than the first thickness and the third thickness; and (b) removing the first tungsten portion and the second tungsten portion, wherein the second tungsten portion is completely removed from the sidewalls and the third tungsten portion remains on the dielectric bottom surface.

[0067] In some embodiments, the present disclosure relates to a method of selectively depositing a tungsten layer on a dielectric surface, the method comprising: (a) depositing a tungsten layer via a physical vapor deposition (PVD) process on a substrate region and on sidewalls of features disposed within the substrate and on the dielectric bottom surface to form a first tungsten portion having a first thickness on the substrate region, a second tungsten portion having a second thickness on the sidewalls, and a third tungsten portion having a third thickness on the dielectric bottom surface, wherein the second thickness is less than the first thickness and the third thickness; (b) oxidizing the top surface of the tungsten layer to form a first tungsten oxide portion on the substrate region, a second tungsten oxide portion on the sidewalls, and a third tungsten oxide portion on the dielectric bottom surface; (c) removing the first tungsten oxide portion, the second tungsten oxide portion, and the third tungsten oxide portion, wherein the second tungsten portion is completely removed from the sidewalls; and (d) stabilizing or completely removing the first tungsten portion from the substrate region. In an embodiment, (a), (b), (c), and (d) are performed sequentially. In an embodiment, (b) and (c) are periodically repeated in a period sufficient to remove the first tungsten portion from the region of the substrate, and the third tungsten oxide portion remains on the dielectric bottom surface. In some embodiments, depositing comprises forming a first thickness and a third thickness greater than the second thickness. In an embodiment, the oxidation is characterized as conformal or superconformal. In an embodiment, oxidizing comprises contacting the top surface of the tungsten layer with an oxygen plasma. In an embodiment, removing comprises contacting the first tungsten oxide portion, the second tungsten oxide portion, and the third tungsten oxide portion with WF6 under conditions sufficient to remove the second tungsten oxide portion from the sidewalls. In an embodiment, stabilizing comprises contacting the first tungsten portion with a remote nitrogen plasma at a temperature of about 300 to about 400 degrees Celsius and a pressure of about 500 millitorr to about 1 torr, wherein nitrogen is provided at a flow rate of about 0.5 to 5 sccm or less than 5 sccm.In some embodiments, oxidizing further comprises providing capacitively coupled plasma containing oxygen at a temperature of about 300 degrees Celsius to about 400 degrees Celsius.

[0068] In some embodiments, a method of selectively depositing a tungsten layer on a dielectric surface comprises: (a) depositing a tungsten layer via a physical vapor deposition (PVD) process on a substrate region and sidewalls of features disposed within the substrate and on the dielectric bottom surface to form a first tungsten portion having a first thickness on the substrate region, a second tungsten portion having a second thickness on the sidewalls, and a third tungsten portion having a third thickness on the dielectric bottom surface, wherein the second thickness is less than the first thickness and the third thickness; and (b) removing the first tungsten portion and the second tungsten portion, wherein the second tungsten portion is completely removed from the sidewalls and the third tungsten portion remains on the dielectric bottom surface. In some embodiments, depositing comprises forming a first thickness and a third thickness that are greater than the second thickness. In an embodiment, removing further comprises contacting the substrate with WF6 under conditions sufficient to remove tungsten from the sidewalls.

[0069] In some embodiments, the present disclosure relates to a method of selectively depositing a tungsten layer on a dielectric surface, the method comprising: (a) depositing a tungsten layer via a physical vapor deposition (PVD) process on a substrate region and sidewalls of features disposed within the substrate and on the dielectric bottom surface to form a first tungsten portion having a first thickness on the substrate region, a second tungsten portion having a second thickness on the sidewalls, and a third tungsten portion having a third thickness on the dielectric bottom surface, wherein the second thickness is less than the first thickness and the third thickness; (b) oxidizing the top surface of the tungsten layer to form a first tungsten oxide portion on the substrate region, a second tungsten oxide portion on the sidewalls, and a third tungsten oxide portion on the dielectric bottom surface; (c) removing the first tungsten oxide portion, the second tungsten oxide portion, and the third tungsten oxide portion, wherein the second tungsten portion is completely removed from the sidewalls; and (d) stabilizing or completely removing the first tungsten portion from the substrate region. In some embodiments, the first thickness is about 7-9 nm, the second thickness is about 1-3 nm, and the third thickness is about 9-11 nm. In some embodiments, depositing comprises forming the first thickness and the third thickness that are greater than the second thickness. In some embodiments, the first thickness is about 8 nm, the second thickness is about 2 nm, and the third thickness is about 10 nm. In some embodiments, the first tungsten oxide portion has a thickness of about 3-7 nm. In some embodiments, the second tungsten oxide portion has a thickness equal to the second thickness or the thickness of the second tungsten portion and can have a thickness such as about 1-3 nm. In some embodiments, the third tungsten oxide portion has a thickness of about 3-7 nm, such as about 5, 6, or 7 nm.

[0070] In some embodiments, the present disclosure relates to a method for selectively depositing a tungsten layer on a dielectric surface, the method comprising: (a) depositing a tungsten layer via a physical vapor deposition (PVD) process on a substrate region, sidewalls of features disposed within the substrate, and on a dielectric bottom surface to form a first tungsten portion having a first thickness on the substrate region, a second tungsten portion having a second thickness on the sidewalls, and a third tungsten portion having a third thickness on the dielectric bottom surface, wherein the second thickness is less than the first thickness and the third thickness; and (b) removing the first tungsten portion and the second tungsten portion such that the first tungsten portion and the second tungsten portion are completely removed from the substrate and the third tungsten portion remains on the dielectric bottom surface. In embodiments, the first thickness is less than the third thickness. In embodiments, depositing further comprises forming a first thickness that is less than the third thickness. In embodiments, depositing further comprises forming a first thickness and a third thickness that are greater than the second thickness. In embodiments, the first thickness is about 7-9 nm. In embodiments, the second thickness is about 1-3 nm. In embodiments, the third thickness is about 9-11 nm. In embodiments, the first thickness is about 8 nm, the second thickness is about 2 nm, and the third thickness is about 10 nm.

[0071] The foregoing is directed to embodiments of the present disclosure, but other and further embodiments of the present disclosure may be devised without departing from the basic scope thereof.

Claims

1. A method for selectively depositing a tungsten layer on a dielectric surface, comprising: (a) depositing a tungsten layer via a physical vapor deposition (PVD) process on a substrate region, sidewalls of features disposed within the substrate, and a dielectric bottom surface to form a first tungsten portion having a first thickness on the substrate region, a second tungsten portion having a second thickness on the sidewalls, and a third tungsten portion having a third thickness on the dielectric bottom surface, wherein the second thickness is smaller than the first thickness and the third thickness; (b) conformally oxidizing the top surface of the tungsten layer to form a first tungsten oxide portion on the substrate region, a second tungsten oxide portion on the sidewalls, and a third tungsten oxide portion on the dielectric bottom surface; (c) removing the first tungsten oxide portion, the second tungsten oxide portion, and the third tungsten oxide portion, wherein the second tungsten portion is completely removed from the substrate and the third tungsten portion remains on the dielectric bottom surface; (d) stabilizing or completely removing the first tungsten portion from the substrate region A method comprising the above steps.

2. The method according to claim 1, wherein in (c), the first tungsten portion is completely removed from the substrate.

3. The method according to claim 1, wherein oxidizing the top surface of the tungsten layer comprises contacting the top surface of the tungsten layer with an oxygen plasma.

4. The method according to claim 1, wherein oxidizing further comprises providing a capacitively coupled plasma containing oxygen at a temperature of about 300 degrees Celsius to about 400 degrees Celsius.

5. Removing the first tungsten oxide portion, the second tungsten oxide portion, and the third tungsten oxide portion with WF under conditions sufficient to remove the second tungsten oxide portion from the sidewalls 6 The method according to claim 1, comprising contacting with WF

6. The method according to claim 1, wherein the first tungsten portion is stabilized, and stabilizing the first tungsten portion comprises contacting the first tungsten portion with a remote nitrogen plasma at a temperature of about 300 to about 400 degrees Celsius, and nitrogen is provided at a flow rate of about 0.5 to 5 sccm or less than 5 sccm.

7. The method according to claim 1, wherein stabilizing the first tungsten portion comprises contacting the first tungsten portion with a remote nitrogen plasma at a pressure of about 500 millitorr to about 1 torr, and nitrogen is provided at a flow rate of about 0.5 to 5 sccm or less than 5 sccm.

8. The method according to any one of claims 1 to 7, wherein (b) and (c) are periodically repeated at a period sufficient to remove the first tungsten portion from the substrate region, and the third tungsten oxide portion remains on the dielectric bottom surface. **Claim 9** The first thickness is about 7 to 9 nm, the second thickness is about 1 to 3 nm, or the third thickness is about 9 to 11 nm The method according to any one of claims 1 to 8, which is at least one of. **Claim 10** The method according to any one of claims 1 to 9, wherein the first thickness is smaller than the third thickness. **Claim 11** A non-transitory computer-readable medium storing instructions that, when executed, cause a reaction chamber to selectively deposit a tungsten layer on a dielectric surface, the method of selectively depositing a tungsten layer on a dielectric surface being the method according to any one of claims 1 to 10.

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