Methods for selectively depositing tungsten on a dielectric layer for bottom-up gap filling

Abstract

Methods and apparatus for selectively depositing a tungsten layer on a dielectric surface are provided. In embodiments, the method comprises: depositing a tungsten layer on a substrate field and on the sidewalls of a feature disposed on the substrate and on the dielectric bottom surface via a PVD process to form a first tungsten portion having a first thickness on the field, 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 is smaller than the first thickness and the third thickness —; oxidizing the top surface of the tungsten layer to form a first oxidized tungsten portion on the field, a second oxidized tungsten portion on the sidewalls, and a third oxidized tungsten portion on the bottom surface; and removing the first, second, and third oxidized tungsten portions — the second tungsten portion is completely removed from the sidewalls —; and includes the step of passivating the first tungsten portion or completely removing it from the field.

Description

Technology Field

[0001] The embodiments of the present disclosure generally relate to methods for selectively depositing tungsten on a dielectric layer (atop). Background Technology

[0002] The geometric structures of semiconductor devices are continuously shrinking to enable semiconductor manufacturing equipment to produce devices with feature sizes of less than 30 nm, and new equipment is being developed and implemented to manufacture devices with even smaller geometric structures. Reducing feature sizes create structural features on devices with reduced spatial dimensions. The widths of gaps and trenches on the device narrow to a point where the gap depth-to-width aspect ratio becomes high enough to make it difficult to fill the gap with material. Since the top of the deposited material tends to become blocked before the gap is fully filled, it creates a void or seam in the middle of the gap.

[0003] Gap-filling 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 devices on a silicon substrate and a first metal layer. In conventional tungsten deposition processes, a wafer is heated to a process temperature in a vacuum chamber where a tungsten film (bulk layer) is deposited on a nucleation layer. The inventors have discovered that, despite the conformal nature of CVD bulk layer tungsten deposition, trenches can problematicly promote the formation of trapped pockets within the gap-filling tungsten.

[0004] Although physical vapor deposition (PVD) techniques are known, the inventors have observed that gap filling problems remain because the thickness of the PVD-deposited tungsten film can vary depending on whether the film is deposited on the substrate field, the sidewalls of the feature, or the bottom of the feature. PVD tungsten deposition generally deposits a non-selective blanket layer of a material that is not useful as a substrate for continuous selective deposition. The inventors have also observed that PVD deposition of tungsten is problematic on non-conductive surfaces such as dielectric materials.

[0005] Selective deposition processes can advantageously reduce the number and cost of steps associated with conventional lithography while maintaining the pace of device dimension shrinkage. Since tungsten is an important material widely used to reduce contact resistance at transistor connections, tungsten-integrated selective deposition has high potential value. The inventors have observed that the poor selectivity of tungsten materials between silicon and dielectrics such as silicon nitride and silicon oxide poses a serious problem in maximizing metal feature filling; for example, poor selectivity can lead to the deposition of tungsten material on the sidewalls and bottoms of high aspect ratio features and limit the ability to fill features with the desired metal material. Since poor selectivity can promote substrate non-uniformity, high selective deposition of tungsten material is required to reduce contact resistance and maximize the volume of feature filling material.

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

[0007] Methods and apparatus 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 comprises: (a) depositing a tungsten layer on a substrate field and on the sidewalls of a feature disposed on the substrate and on the dielectric bottom surface via a physical vapor deposition (PVD) process to form a first tungsten portion having a first thickness on the substrate field, 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 is smaller than the first thickness and the third thickness —; (b) oxidizing the top surface of the tungsten layer to form a first oxidized tungsten portion on the substrate field, a second oxidized tungsten portion on the sidewalls, and a third oxidized tungsten portion on the dielectric bottom surface; (c) a step of removing a first oxidized tungsten portion, a second oxidized tungsten portion, and a third oxidized tungsten portion — the second tungsten portion is completely removed from the sidewall —; and (d) a step of passivating the first tungsten portion or completely removing it from the substrate field. In the embodiments, the first oxidized tungsten portion on the substrate field is thicker than the third oxidized tungsten portion on the dielectric bottom surface. In the embodiments, retaining the third tungsten portion or a portion of the third tungsten portion on the dielectric bottom surface facilitates selective tungsten growth.

[0008] In some embodiments, a method for selectively depositing a tungsten layer on a dielectric bottom surface comprises: (a) depositing a tungsten layer on a substrate field and on the sidewalls of a feature disposed on the substrate and on the dielectric bottom surface through a physical vapor deposition (PVD) process to form a first tungsten portion having a first thickness on the substrate field, 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 is smaller than the first thickness and the third thickness —; and (b) removing the first tungsten portion and the second tungsten portion, 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. In the embodiments, the first thickness is smaller than the third thickness.

[0009] In some embodiments, the present disclosure relates to a non-transient computer-readable medium storing instructions that, when executed, cause a reaction chamber to perform a method of selectively depositing a tungsten layer on a dielectric surface, wherein the method of selectively depositing a tungsten layer on a dielectric surface comprises: (a) a step of depositing a tungsten layer on a substrate field and on the sidewalls of a feature disposed on the substrate and on the dielectric bottom surface through a physical vapor deposition (PVD) process to form a first tungsten portion having a first thickness on the substrate field, 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 is smaller than the first thickness and the third thickness —; (b) a step of oxidizing the top surface of the tungsten layer to form a first oxidized tungsten portion on the substrate field, a second oxidized tungsten portion on the sidewalls, and a third oxidized tungsten portion on the dielectric bottom surface; (c) a step of removing the first oxidized tungsten portion, the second oxidized tungsten portion, and the third oxidized tungsten portion — the second tungsten portion is completely removed from the sidewall —; and (d) a step of passivating the first tungsten portion or completely removing it from the substrate field.

[0010] In some embodiments, the present disclosure relates to a non-transient computer-readable medium storing instructions that, when executed, cause a reaction chamber to perform a method of selectively depositing a tungsten layer on a dielectric surface, wherein the method of selectively depositing a tungsten layer on a dielectric surface comprises: (a) a step of depositing a tungsten layer on a substrate field and on a sidewall of a feature disposed on the substrate and on a dielectric bottom surface through a physical vapor deposition (PVD) process to form a first tungsten portion having a first thickness on the substrate field, a second tungsten portion having a second thickness on the sidewall, and a third tungsten portion having a third thickness on the dielectric bottom surface — the second thickness is smaller than the first thickness and the third thickness —; and (b) a step of removing the first tungsten portion and the second tungsten portion, 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.

[0011] Other and additional embodiments of the present disclosure are described below. Brief explanation of the drawing

[0012] Embodiments of the present disclosure, briefly summarized above and discussed in more detail below, may be understood by reference to exemplary embodiments of the present disclosure depicted in the accompanying drawings. However, the accompanying drawings are merely illustrative of typical embodiments of the present disclosure and should not be construed as limiting the scope, as the present disclosure may allow for other equally valid embodiments.

[0013] FIG. 1 illustrates a flowchart of a method for selectively depositing a tungsten layer on a dielectric surface according to embodiments of the present disclosure.

[0014] FIGS. 2a to 2e each illustrate stages for selectively depositing a tungsten layer on a dielectric surface according to embodiments such as FIG. 1 of the present disclosure.

[0015] FIGS. 3a to 3e each illustrate stages for selectively depositing a tungsten layer on a dielectric surface according to embodiments of the present disclosure.

[0016] FIGS. 4a to 4d each illustrate stages for selectively depositing a tungsten layer on a dielectric surface according to embodiments of the present disclosure.

[0017] FIGS. 5a to 5e each illustrate stages for selectively depositing a tungsten layer on a dielectric surface according to embodiments of the present disclosure.

[0018] FIG. 6 illustrates a cluster tool suitable for performing methods for processing a substrate according to some embodiments of the present disclosure.

[0019] FIG. 7 illustrates a flowchart of a method for selectively depositing a tungsten layer on a dielectric surface according to embodiments of the present disclosure.

[0020] For ease of understanding, the same reference numbers have been used where possible to designate identical elements common to the drawings. The drawings are not drawn to actual scale and may be simplified for clarity. The elements and features of one embodiment may be advantageously incorporated into other embodiments without further mention. Specific details for implementing the invention

[0021] The inventors have observed that tungsten deposited within a feature can advantageously be selectively formed directly on a dielectric layer according to the present disclosure. Selectively depositing tungsten directly on a dielectric layer advantageously provides bottom-up gap filling, thereby reducing or eliminating the formation of voids or seams within the feature. Reducing or eliminating voids within the feature reduces resistance, leads to increased device yield, reduces manufacturing costs, and provides increased uniformity across multiple features during the formation of the semiconductor device. Increased uniformity improves the application of additional process layers as manufacturing continues.

[0022] FIG. 1 is a flowchart of a method (100) for selectively depositing a tungsten layer on a dielectric surface according to some embodiments of the present disclosure. The method (100) is described below in relation to stages for processing a substrate as illustrated in FIGS. 2a through 2e. The methods described herein may be performed in physical vapor deposition (PVD) chambers or etching chambers, which may be provided as a standalone configuration or as part of one or more cluster tools, e.g., as illustrated in FIG. 6 (i.e., cluster tools), or in individual process chambers such as those available from Applied Materials, Inc. of Santa Clara, California. Other process chambers, including those available from other manufacturers, may also be adapted to benefit from the present disclosure.

[0023] The method (100) is generally performed on a substrate (200) provided in a processing volume of a process chamber. In some embodiments, as shown in FIG. 2a, the substrate (200) includes one or more features such as a trench (210) (shown in FIG. 2a through 2e) which is optionally filled with a tungsten layer (231), and the trench (210) extends toward the base (214) of the substrate (200). Although the following description is for one feature, the substrate (200) may include any number of features (such as multiple trenches (210), vias, self-aligned vias, self-aligned contact features, dual damascene structures, etc.) as described below, or may be suitable for use in a number of 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.

[0024] In the embodiments, the substrate (200) may be formed of or include one or more of silicon (Si), silicon oxide, such as silicon monoxide (SiO) or silicon dioxide (SiO2), silicon nitride (such as SiN), etc. In non-limiting embodiments, the substrate (200) may have a trench (210) formed in a dielectric layer, and thus the dielectric layer may be the substrate (200) or made of the same materials described above, such as SiN, SiO, etc. In the embodiments, a low-k dielectric material may be suitable for the substrate (200) or the layer thereof (e.g., a material having a dielectric constant lower than silicon oxide, or less than about 3.9). Additionally, the substrate (200) may include additional layers of materials or may have one or more completed or partially completed structures or devices (not shown) formed within the substrate (200), on the substrate, or under the substrate. In the embodiments, the substrate (200) or one or more of the layers thereof may 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) comprises a semiconductor wafer. In the embodiments, the material of the substrate (200) at the bottom of the trench (210) is a dielectric material extending across the bottom of the trench (210).

[0025] In the embodiments, the substrate (200) may not be limited to any size or shape. The substrate (200) may be a circular wafer having different diameters, such as 200 mm, 300 mm, or 450 mm. The substrate (200) may also be any polygonal, square, rectangular, curved, or other non-circular workpiece, such as a polygonal glass substrate used in the manufacture of flat panel displays.

[0026] In some embodiments, features such as trenches (210) may be formed by etching the substrate (200) using any suitable etching process. In some embodiments, feature(s) suitable for use according to the present disclosure comprise one or more trench(s) with a high aspect ratio of depth to width having a width of less than 20 nanometers. In some embodiments, the trench (210) is defined by a substrate field (225), a sidewall (220), a dielectric bottom surface (222) of the feature such as the trench (210), and upper corner(s) (224) disposed on the substrate (200). In some embodiments, the trench (210) may have a high aspect ratio, for example, an aspect ratio of 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 the embodiments, the trench (210) has a width as indicated by arrow 226, which is 20 nanometers or less, or 10 nanometers or less, or a width as indicated by arrow 226, which is 5 to 10 nanometers.

[0027] Referring to FIG. 2b, in some embodiments, the substrate (200) comprises or is composed of a dielectric layer of the above-described material such as silicon oxide, silicon monooxide (SiO), silicon dioxide (SiO2), silicon nitride (e.g., SiN), tetraethyl orthosilicate (TEOS), etc., and is shaped to have an opening (211) of the substrate field (225), a surface opposite the opening (211), such as a dielectric bottom surface (222), and a sidewall (220) between the opening (211) and the dielectric bottom surface (222), i.e., the surface opposite the opening (211).

[0028] Now, referring to 102 in FIG. 1 and FIG. 2b, the method (100) comprises the step of depositing a tungsten layer (231) by a physical vapor deposition (PVD) process on a substrate field (225), on a sidewall (220), and on a dielectric bottom surface (222) of a feature such as a trench (210) placed on the substrate (200) to form a first tungsten portion having a first thickness on the substrate field (225), a second tungsten portion having a second thickness on the sidewall (220), and a third tungsten portion having a third thickness on the dielectric bottom surface (222), wherein the second thickness is smaller than the first thickness and the third thickness. For example, in some embodiments, the tungsten layer (231) is deposited on the substrate (200) and within a feature such as a trench (210) in a process chamber configured to PVD deposit the tungsten layer (231). In the embodiments, the tungsten layer (231) may be a layer formed non-conformally along the sidewalls (220) of a feature such as a trench (210) and the dielectric bottom surface (222) over the substrate field (225), so that a substantial portion of the feature prior to the deposition of the layer remains unfilled after the deposition of the layer, wherein a first tungsten portion (indicated by arrow 235) having a first thickness (indicated by arrow 236) is placed over or immediately above the substrate field (225), a second tungsten portion (adjacent to arrow 237) having a second thickness (indicated by arrow 238) is placed over or immediately above the sidewall (220), and a third tungsten portion (indicated by arrow 239) having a third thickness (indicated by arrow 240) is placed over or immediately above the dielectric bottom surface (222), wherein the second The thickness (indicated by arrow 238) is smaller than the first thickness (indicated by arrow 236) and the third thickness (indicated by arrow 240). FIG. 2b is not drawn to actual scale. FIG. 2b is not drawn to actual scale, and in the embodiments, the first thickness, the second thickness, and the third thickness are not the same.

[0029] In some embodiments, the tungsten layer (231) may be formed along the entire length of the sidewall (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 sidewall (220) than on the substrate field (225) or the dielectric bottom surface (222). For example, in some embodiments, a first tungsten portion (indicated by arrow 235) has a first thickness (indicated by arrow 236) in an amount of 3 to 6 nm, a second tungsten portion is placed on the sidewall (220) having a second thickness different from the first thickness, and a third tungsten portion (indicated by arrow 239) has a third thickness (indicated by arrow 240) in an amount of 3 to 6 nm. In the embodiments, the first thickness and the third thickness are thicker than the thickness of the second tungsten portion on the sidewall (220). In the embodiments, the second tungsten portion has a second thickness of 0.5 to 1.5 nm, such as about 1 nm. In the embodiments, the first thickness is smaller than the third thickness. In the embodiments, the first thickness and the third thickness are each individually larger than the second thickness. In the embodiments, the first thickness is about 7 to 9 nm. In the embodiments, the second thickness is about 1 to 3 nm. In the embodiments, the third thickness is about 9 to 11 nm. In the embodiments, the first thickness is about 8 nm, the second thickness is about 2 nm, and the third thickness is about 10 nm.

[0030] In some embodiments, the thickness of the tungsten layer (231) is predetermined to fill the gap of a feature, such as a trench, via, self-aligned via, dual damascene structure, etc. In embodiments, 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 embodiments, the feature is filled only about 5 to 25%, such as about 10%, 15%, or 20% above the dielectric bottom surface (222).

[0031] Referring still to FIG. 2b, a tungsten layer (231) is shown PVD deposited on a substrate (200) and within a feature such as a trench (210). In the embodiments, the tungsten layer (231) comprises tungsten or a tungsten alloy. In some embodiments, however, the tungsten layer (231) may also comprise 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 the embodiments, the tungsten and tungsten-containing material is substantially pure tungsten, or tungsten having impurities of 1, 2, 3, 4, or 5% or less.

[0032] In some embodiments, as illustrated in FIG. 2b, a tungsten layer (231) is deposited on the dielectric bottom surface (222) of the substrate (200) and within a trench (210) formed in the substrate (200). The tungsten layer (231) may be deposited using any PVD system available from Applied Materials, Inc., Santa Clara, California. Other suitable PVD process chambers may be used similarly. In some embodiments, suitable process conditions for PVD depositing the tungsten layer (231) include process conditions suitable for heating the substrate at a temperature in the range of about 450 degrees Celsius to about 600 degrees Celsius, or at a temperature in the range of about 450 degrees Celsius to about 500 degrees Celsius. In some embodiments, the process chamber for depositing the tungsten is maintained at a pressure in the range of about 1 Torr to about 150 Torr, or in the range of about 5 Torr to about 90 Torr.

[0033] Referring to 104 of FIG. 1, embodiments of the present disclosure include oxidizing the top surface (251) of a tungsten layer (231) to form a first oxidized tungsten portion (254) on a substrate field, a second oxidized tungsten portion (256) on a sidewall (220), and a third oxidized tungsten portion (258) on a dielectric bottom surface. In the embodiments, plasma and oxygen are applied under conditions sufficient to partially convert the tungsten of the first and third tungsten portions into tungsten oxide (WOx), while completely converting the second tungsten portion on the sidewall (220) into tungsten oxide. In the embodiments, the first tungsten portion (indicated by arrow 235 in FIG. 2b) is partially converted into tungsten oxide from top to bottom, for example, along the length of the first tungsten portion, and the third tungsten portion (indicated by arrow 239 in FIG. 2b) is partially converted into tungsten oxide from top to bottom, for example, along the length of the first portion, while the second tungsten portion above the sidewall (220) is completely converted into tungsten oxide.

[0034] In some embodiments, the first tungsten portion (indicated by arrow 235), the second tungsten portion (adjacent to arrow 237), and the third tungsten portion (indicated by arrow 239) are each partially or completely oxidized by a radical oxidation process provided to the substrate so that a sufficient amount of oxygen comes into contact with the tungsten portions positioned above. In some embodiments, an oxygen flux is provided in an amount sufficient 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.

[0035] In some embodiments, the first oxidized tungsten portion has a thickness of about 3 to 7 nm. In some embodiments, the second oxidized tungsten portion has a thickness equal to the second thickness or the thickness of the second tungsten portion, and may have a thickness such as about 1 to 3 nm. In some embodiments, the third oxidized tungsten portion has a thickness of about 3 to 7 nm, such as about 5, 6, or 7 nm.

[0036] In some embodiments, an oxidation process is performed in a process chamber on a substrate (200) having a first tungsten portion (indicated by arrow 235), a second tungsten portion (adjacent to arrow 237), and a third tungsten portion (indicated by arrow 239) using oxygen radicals to form the structure shown in FIG. 2c. In the embodiments, oxygen gas and argon gas are applied to the substrate. Plasma power is applied to the gases to generate oxygen radicals, etc. The radicals react with the substrate (200) and the first tungsten portion (indicated by arrow 235), the second tungsten portion (adjacent to arrow 237 in FIG. 2b), and the third tungsten portion (indicated by arrow 239 in FIG. 2b) to form an oxide layer on the first tungsten portion, the second tungsten portion, and the third tungsten portion. In some embodiments, the oxidation process may be performed at an optimally controlled temperature. In some embodiments, the oxidation process may be performed at a temperature of about 200 degrees Celsius to about 400 degrees Celsius.

[0037] In some embodiments, a substrate (200) having a first tungsten portion (indicated by arrow 235), a second tungsten portion (adjacent to arrow 237), and a third tungsten portion (indicated by arrow 239) is loaded into a chamber. The chamber is stabilized by controlling the pressure and temperature within the chamber. An inert gas may be introduced into the chamber to adjust the pressure within the chamber. The chamber has a temperature of about 200 degrees Celsius to about 400 degrees Celsius, or about 250 degrees Celsius to about 280 degrees Celsius. In some embodiments, plasma power is applied within the chamber to generate plasma in the chamber. In some embodiments, the plasma power is in the range of about 1,000 W to about 5,000 W. In some embodiments, a pressure suitable for the oxidation process is provided to the chamber to which plasma power is continuously applied. In some embodiments, the pressure is about 1 mTorr to 100 mTorr. In some embodiments, oxygen gas is introduced into the chamber to perform a primary oxidation process when the chamber is maintained under that pressure. Additionally, an inert gas, such as argon gas, may be introduced into the chamber along with the oxygen gas. In some embodiments, argon gas is included to function to rapidly generate plasma. In some embodiments, the flux of oxygen gas is provided in an amount sufficient to completely oxidize all tungsten placed on the sidewall (220) of the tungsten layer pattern and partially oxidize the first tungsten portion (indicated by arrow 235) on the substrate field (225) and the third tungsten portion (indicated by arrow 239) on the dielectric bottom surface (222) to form tungsten oxide (WOx, where x is an integer). In the embodiments, the first tungsten portion (indicated by arrow 235) and the third tungsten portion (indicated by arrow 239) above the substrate field (225) are oxidized from top to bottom to a depth of 0.5 to 2.0 nm, or about 1 to 1.5 nm.

[0038] Now, referring to the process sequence (106) of the method (100) and FIG. 2c and FIG. 2d, the present disclosure comprises removing a first oxidized tungsten portion (indicated by arrow 261 below), a second oxidized tungsten portion (indicated by adjacent arrow 263), and a third oxidized tungsten portion (indicated by adjacent arrow 262), wherein the second oxidized tungsten portion (indicated by adjacent arrow 263) is completely removed from the sidewall. Thus, since all tungsten on the sidewall (220) is oxidized and all second oxidized tungsten is removed, all tungsten is removed from the sidewall (220) as shown in FIG. 2d. In the embodiments, now referring 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 the sidewall (220) of the tungsten layer pattern, thereby forming the structure shown in FIG. 2d without tungsten oxide on the sidewall (220). In some embodiments, tungsten hexafluoride (WF6) is provided in an amount sufficient to immerse the structure shown in FIG. 2d and remove all tungsten oxide from the sidewall (220). As shown in FIG. 2d, at least a portion of the third tungsten portion remains on the dielectric bottom surface (222), and at least a portion of the first tungsten portion remains on the substrate field (225). In the embodiments, examples of reducing gases may include hydrogen gas and NH3 gas. In the embodiments, hydrogen gas and NH3 gas may be used alone or as a mixture thereof. In these embodiments, the reducing gas containing WF6 is used alone.

[0039] Now, referring to the process sequence (108) of the method (100) and FIG. 2e, the present disclosure includes passivating the first tungsten portion or completely removing the first tungsten portion from the substrate field (225). For example, FIG. 2e illustrates passivating the first tungsten portion from the substrate field (225) by forming a tungsten nitride layer (271) on or inside the first tungsten portion (273) on the substrate field (225). In the embodiments, the tungsten nitride layer (271) is formed by a remote plasma reaction between nitrogen (N2), hydrogen (H2), and argon (Ar) in a process chamber at a first temperature of 300 to 400 degrees Celsius and a pressure of 50 mTorr to 1 Torr. In some embodiments, the method (100) includes the step of flowing reaction products from a remote plasma reaction into a process chamber to selectively form a tungsten nitride layer (271) on the surface of a first tungsten portion (273). In some embodiments, the top surface (280) of a third tungsten portion does not come into contact with the remote plasma or the reactants of the remote plasma and does not react with nitrogen. In some embodiments, the remote plasma reaction reacts nitrogen (N2) and argon (Ar) at a first temperature of 300 to 400 degrees Celsius. In some embodiments, about 65 watts of RF energy is applied to the remote plasma reaction. In some embodiments, the tungsten nitride layer (271) is deposited with a predetermined thickness, such as about 10 angstroms to about 100 angstroms, or about 100 to about 500 angstroms.

[0040] In some embodiments, the nitriding process sequence or direct plasma reaction of the process sequence (108) provides nitrogen at a flow rate of about 5 sccm or less. In embodiments, the pressure in the process chamber during the direct plasma reaction is maintained at 50 mTorr to 1 Torr. In embodiments, RF power is applied during the direct plasma reaction at about 100 watts to 1000 watts. In embodiments, the nitriding process is characterized by a weak nitrogen-based plasma that provides almost no nitrogen to the structure shown in FIG. 2d so that only the top surface of the tungsten placed on the substrate field (225) reacts with the nitrogen plasma. In embodiments, after passivation or removal of the first tungsten portion, only the third tungsten portion (274) remains available for selective deposition in downstream processing of the substrate (200).

[0041] FIGS. 3a through 3e respectively illustrate stages for selectively depositing a tungsten layer on a dielectric surface according to embodiments of the present disclosure. For example, in some embodiments, the present disclosure relates to a method for selectively depositing a tungsten layer on a dielectric surface, the method comprising: depositing a tungsten layer on a substrate field and on a sidewall of a feature disposed on the substrate and on a dielectric bottom surface through a physical vapor deposition (PVD) process to form a first tungsten portion having a first thickness on the substrate field, a second tungsten portion having a second thickness on the sidewall, 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—; and oxidizing the top surface of the tungsten layer to form a first oxidized tungsten portion on the substrate field, a second oxidized tungsten portion on the sidewall, and a third oxidized tungsten portion on the dielectric bottom surface; The method includes the step of removing a first oxidized tungsten portion, a second oxidized tungsten portion, and a third oxidized tungsten portion — wherein the second tungsten portion is completely removed from the sidewall —; and the step of removing the first tungsten portion from the substrate field.

[0042] FIG. 3a illustrates a substrate (200) comprising the embodiments described above in FIG. 2a. FIG. 3b illustrates a PVD-deposited tungsten layer (231) on the substrate field (225), on the sidewall (220), and on the dielectric bottom surface (222) of a feature such as a trench (210) disposed on the substrate (200), so as to form a first tungsten portion (291) having a first thickness on the substrate field (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 the embodiments, the second thickness is smaller than the first thickness and the third thickness.

[0043] Referring to FIG. 3c, embodiments of the present disclosure include oxidizing the top surface (251) of a tungsten layer (231) to form a first oxidized tungsten portion (254) on a substrate field, a second oxidized tungsten portion (256) on a sidewall (220), and a third oxidized tungsten portion (258) on a dielectric bottom surface or on tungsten deposited on a dielectric bottom surface. In the embodiments, plasma and oxygen are applied under conditions sufficient to partially convert the tungsten of the first and third tungsten portions into tungsten oxide, while completely converting the tungsten portion on the sidewall (220) into tungsten oxide. In the embodiments, the first tungsten portion is converted more into tungsten oxide than the third tungsten portion. In the embodiments, the present disclosure includes pre-selecting or tuning the thickness of a first oxidized tungsten portion (254) while limiting the thickness of a third oxidized tungsten portion (258) on a dielectric bottom surface (222) or tungsten (299) deposited on the dielectric bottom surface (222).

[0044] In some embodiments, the degree or thickness of tungsten oxidation may be controlled by dissociation and plasma properties to adjust the tungsten oxidation to provide improved etching performance. For example, in some embodiments comprising a reduced power capacitance coupled plasma (CCP) within a process chamber containing a substrate (200), chamber degradation may be reduced, which provides an improved process. Thus, the systems described herein provide improved flexibility in terms of chemical modulation while also providing improved etching performance. In some embodiments, non-limiting process chambers suitable for etching according to the present disclosure are illustrated and described in U.S. Patent No. 9,362,130, granted to Ingle et al. on June 7, 2016, and assigned to Applied Materials, Inc. under the title of the invention “Enhanced Etching Processes Using Remote Plasma Sources”. In some embodiments, the processing chamber for use herein is coupled to a remote plasma source that provides gaseous 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 fluidly connected to a processing chamber containing a substrate (200).

[0045] In some embodiments, a remote plasma region of a processing chamber, such as an etching chamber, may be configured for a capacitively coupled plasma ("CCP") formed within a region of the processing chamber. In some embodiments, the plasma configurations of the remote plasma region may be fluidly located, for example, between another remote plasma region and a processing region. In some embodiments, the remote plasma region may be defined by two or more electrodes that allow plasma to be formed within the region. In some embodiments, the CCP may be operated at reduced or substantially reduced power because it may be used only to maintain oxygen-containing plasma effluents and may not be used to completely ionize species within the plasma region. For example, the CCP may be operated at power levels of about 400 W, 250 W, 200 W, 150 W, 100 W, 50 W, 20 W, etc., or lower. Additionally, the CCP may generate a flat plasma profile capable of providing a uniform plasma distribution within space. In this way, a more uniform plasma can be delivered to the first tungsten portion (291) and the second tungsten portion (292) without reaching the third tungsten portion (293). Accordingly, the first tungsten portion (291) may be more oxidized than the third tungsten portion (293), or a thicker tungsten oxide layer may be formed inside it. In the embodiments, since the second tungsten portion (292) is thin, it is consequently converted entirely into tungsten oxide.

[0046] In some embodiments, an oxygen-containing plasma such as a CCP may be delivered at a power of less than 400 W, for example, between 350 W and 375 W. In some embodiments, the CCP oxygen-containing plasma may be delivered at a temperature of about 300 degrees Celsius to about 400 degrees Celsius. In some embodiments, the CCP oxygen-containing plasma may be delivered, wherein oxygen is provided at a flow rate of less than 50 sccm, such as 30 to 45 sccm. In some embodiments, the CCP oxygen-containing plasma may be delivered for less than 60 seconds, less than 30 seconds, or 10 to 25 seconds.

[0047] Referring to FIG. 3d, the present disclosure includes the step of removing a first oxidized tungsten portion (254), a second oxidized tungsten portion (256), and a third oxidized tungsten portion (258), wherein the second tungsten portion (292) is completely removed from the sidewall (220). In the embodiments, the tungsten oxide is contacted and immersed in tungsten hexafluoride (WF6) as described above. For example, referring now to FIG. 3d, after performing the oxidation process, a reducing gas containing tungsten hexafluoride (WF6) is introduced in-situ into a process chamber containing a substrate (200) to reduce and remove the tungsten oxide (WOx) on the sidewall (220) of the tungsten layer pattern, thereby forming the structure illustrated in FIG. 3d without tungsten oxide on the sidewall (220). In some embodiments, tungsten hexafluoride (WF6) is provided in an amount sufficient to immerse the structure illustrated in FIG. 3d and remove all tungsten oxide from the sidewall (220). In some embodiments, as indicated by arrows 297 and 298, the process sequence of (a) oxidizing the top surface of the tungsten layer to form a first oxidized tungsten portion on the substrate field, a second oxidized tungsten portion on the sidewall, and a third oxidized tungsten portion on the dielectric bottom surface, and (b) removing the first oxidized tungsten portion, the second oxidized tungsten portion, and the third oxidized tungsten portion—the second tungsten portion is completely removed from the sidewall—can be cycled to coordinate the oxidation and removal of tungsten. In the embodiments, process sequences (a) and (b) can be cycled through a sufficient number of cycles to remove all of the first tungsten portion (291) and form the structure shown in FIG. 3e, where only the third tungsten portion (293) remains deposited on or directly on the dielectric material of the substrate (200).In the embodiments, process sequences (a) and (b) may be cycled 1 to 10 times, or 1 to 5 times, to remove the first tungsten portion (291) and form the structure shown in FIG. 3e.

[0048] FIG. 7 is a flowchart of a method (700) for selectively depositing a tungsten layer on a dielectric surface according to some embodiments of the present disclosure. The method (700) is described below in relation to stages for processing a substrate as illustrated in FIG. 4a through 4d. The methods described herein may be performed in physical vapor deposition (PVD) chambers or etching chambers, which may be provided as a standalone configuration or as part of one or more cluster tools, e.g., as illustrated in FIG. 6 (i.e., cluster tools), or in individual process chambers such as those available from Applied Materials, Inc. of Santa Clara, California. Other process chambers, including those available from other manufacturers, may also be adapted to benefit from the present disclosure.

[0049] FIGS. 4a through 4d each illustrate stages for selectively depositing a tungsten layer on a dielectric surface according to embodiments of the present disclosure. For example, in some embodiments, the present disclosure relates to a method for selectively depositing a tungsten layer on a dielectric surface, comprising: a step of depositing a tungsten layer on a substrate field and on the sidewalls of a feature disposed on the substrate and on the dielectric bottom surface via a physical vapor deposition (PVD) process as illustrated in process sequence (702), thereby forming a first tungsten portion having a first thickness on the substrate field, 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 is smaller than the first thickness and the third thickness —; and, as illustrated in process sequence (704), includes the step of removing the first tungsten portion and the second tungsten portion — 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 —.

[0050] FIG. 4a illustrates a substrate (200) comprising the embodiments described above in FIG. 2a. FIG. 4b illustrates a PVD-deposited tungsten layer (231) on the substrate field (225), on the sidewall (220) of a feature such as a trench (210) disposed on the substrate (200), and on the dielectric bottom surface (222) to form a first tungsten portion (291) having a first thickness on the substrate field (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 the embodiments, the second thickness is smaller than the first thickness and the third thickness. PVD reaction conditions and thicknesses such as the first thickness, the second thickness, and the third thickness may be the same as those described above.

[0051] Referring to FIG. 4b and FIG. 4c, embodiments of the present disclosure include the step of removing a first tungsten portion (291) and a second tungsten portion (292), wherein the second tungsten portion (292) is completely removed from the sidewall (220). In some embodiments, tungsten etch back of the first tungsten portion (291) and the second tungsten portion (292) is achieved by contacting the first tungsten portion (291) and the second tungsten portion (292) with a tungsten halide plasma (e.g., WF6 plasma) under conditions sufficient to partially or wholly etch or remove the first tungsten portion (291) and the second tungsten portion (292). In the embodiments, the substrate (200) is placed within a processing chamber containing 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 the atomic fluorine is used to etch the metallic tungsten of at least the first tungsten portion (291) and the second tungsten portion (292). In the embodiments, the etching rate depends on the WF6 flow and plasma conditions. By adjusting the process conditions, a very suitable etching rate in the range of 0.5 angstroms / second to 3 angstroms / second can be achieved to control the amount of etchback. In the embodiments, a single-chamber deposition-etch-deposition process can be achieved because WF6 can be used as both a deposition precursor and an etchant in the chamber. Standard PVD chambers with RF or RPS plasma capabilities can perform both deposition and etchback, thereby improving throughput and chamber redundancy.

[0052] In some embodiments, the first tungsten portion (291) and the second tungsten portion (292) are etched using a tungsten-containing gas to remove portions of the first tungsten portion (291) and the second tungsten portion (292). The etching process (also known as the etch-back process) removes portions of the first tungsten portion (291) and the second tungsten portion (292) along the sidewalls (220). The etching process may also be performed in the same processing chamber as the tungsten deposition process. In embodiments, the plasma may be formed by combining radio frequency (RF) power with a process gas such as helium (He), argon (Ar), oxygen (O2), nitrogen (N2), or a combination thereof. The plasma may be formed by a remote plasma source (RPS) and delivered to the processing chamber.

[0053] In the embodiments, the temperature of the substrate (200) during the etching process may 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 the embodiments, etching of the first tungsten portion (291) and the second tungsten portion (292) may be performed when the pressure of 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 may be approximately 1 Torr. In the embodiments, the process gas (e.g., argon (Ar)) may be introduced at a flow rate in the range of about 100 sccm to about 3,000 sccm. In one example, the argon may be introduced at a total flow rate of 2,000 sccm. In the examples, the tungsten-containing compound for etching may be tungsten hexafluoride (WF6) and may be introduced at a continuous flow rate in the range of about 1 sccm to 150 sccm, such as in the range of about 3 sccm to 100 sccm.

[0054] In the embodiments, after etch-back as described herein, and after removing the first tungsten portion (291) and the second tungsten portion (292) or portions thereof, the substrate (200) may be further processed to form a structure as shown in FIG. 4d. For example, in some embodiments, tungsten hexafluoride (WF6) is provided in an amount sufficient to immerse the structure shown in FIG. 4c and remove all tungsten oxide from the sidewall (220). As shown in FIG. 4c and FIG. 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 field (225) and the sidewall (220). In the embodiments, examples of reducing gases may include hydrogen gas and NH3 gas. In the embodiments, hydrogen gas and NH3 gas may be used alone or as a mixture thereof. In these embodiments, the reducing gas containing WF6 is used alone.

[0055] FIGS. 5a through 5e each illustrate stages for selectively depositing a tungsten layer on a dielectric surface according to embodiments of the present disclosure. For example, in some embodiments, the present disclosure relates to a method for selectively depositing a tungsten layer on a dielectric surface, comprising: depositing a tungsten layer on a substrate field and on the sidewalls of a feature disposed on the substrate and on the dielectric bottom surface through a physical vapor deposition (PVD) process to form a first tungsten portion having a first thickness on the substrate field, 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 is smaller than the first thickness and the third thickness —; and oxidizing the top surface of the tungsten layer to form a first oxidized tungsten portion on the substrate field, a second oxidized tungsten portion on the sidewalls, and a third oxidized tungsten portion on the dielectric bottom surface. The method includes the step of removing a first oxidized tungsten portion, a second oxidized tungsten portion, and a third oxidized tungsten portion — the second tungsten portion is completely removed from the sidewall —; and the step of removing the first tungsten portion from the substrate field.

[0056] FIG. 5a illustrates a substrate (200) comprising the embodiments described above in FIG. 2a. FIG. 5b illustrates a PVD-deposited tungsten layer (231) on the substrate field (225), on the sidewall (220), and on the dielectric bottom surface (222) of a feature such as a trench (210) disposed on the substrate (200) to form a first tungsten portion (291) having a first thickness on the substrate field (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 the embodiments, the second thickness is smaller than the first thickness and the third thickness.

[0057] In the embodiments, the PVD chamber is the same as the chamber disclosed in U.S. Patent No. 9,062,372, granted to Gopalraja et al. and assigned to Applied Materials under the title of the invention “Self-Ionized and Capacitively-Coupled Plasma For Sputtering and Resputtering”. In the embodiments, a suitable process chamber sputter configured to deposit tungsten by self-ionized plasma (SIP) sputtering is provided.

[0058] In the examples, PVD deposition is performed by sputtering tungsten by self-ionizing plasma (SIP) sputtering. In the examples, a magnetic field generated by an electromagnetic coil confines the plasma generated by capacitive coupling, thereby increasing the plasma density and the consequent ionization rate. Long-throw sputtering is characterized by a relatively high ratio of the target-to-substrate distance to the substrate diameter. Long-throw SIP sputtering promotes deep hole coating of both ionized and neutral deposition material components. CCP re-sputtering can reduce the thickness of the bottom coverage of the deep holes to reduce contact resistance.

[0059] In the embodiments, SIP tends to be promoted by low pressures of less than 5 mTorr. Particularly at low pressures, SIP tends to be promoted by magnetrons having relatively small areas that increase the target power density, and by magnetrons having asymmetric magnets that cause the magnetic field to penetrate further toward the substrate. According to one aspect of the present disclosure, plasma conditions for SIP sputtering to deposit a target material are provided.

[0060] In the embodiments, a reactor comprising a DC magnetron type reactor based on a modification of the Endura PVD reactor available from Applied Materials, Inc., Santa Clara, California is provided. In the embodiments, the reactor is capable of self-ionized sputtering (SIP) in a long-throw mode. The SIP mode may be used in one embodiment where non-uniform coverage is required, such as coverage directed mainly toward the sidewalls of the holes. The SIP mode may also be used to achieve more uniform coverage. In another alternative embodiment, the pressure within the chamber may be changed from one step to another. For example, the pressure may be increased during SIP sputtering.

[0061] To attract ions generated by the plasma, the tungsten target can be negatively biased by a variable DC power source, for example, at a DC power of 1 to 40 kW. The source negatively biases the target to about -400 to -600 VDC relative to the chamber shield to ignite and maintain the plasma. Voltages below -1000 VDC are generally suitable for use here. Target power of 1 to 5 kW is generally used to ignite the plasma, whereas power greater than 10 kW is suitable for the SIP sputtering described here. For example, a target power of 24 kW can be used to deposit tungsten by SIP sputtering.

[0062] In the embodiments, the source may apply RF power to the pedestal electrode to bias the substrate to attract deposition material ions during SIP sputter deposition. During SIP deposition, the pedestal and the corresponding substrate (200) may remain electrically floated, but nevertheless, a negative DC self-bias may occur in the pedestal and the corresponding substrate (200). Alternatively, the pedestal may be negatively biased by the source at -30 VDC to negatively bias the substrate to attract ionized deposition material to the substrate.

[0063] In some embodiments, when argon is introduced into the PVD processing chamber, a DC voltage difference between a target, such as a tungsten target, and the chamber shield can ignite the argon into a plasma, and positively charged argon ions are attracted to the negatively charged target. The ions strike the target with significant energy, causing target atoms or atomic clusters to be sputtered from the target. Some of the target particles strike the substrate (200) and are deposited on the substrate (200) to form a PVD-deposited layer of tungsten material as illustrated 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 field (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 the embodiments, the second thickness is smaller than the first thickness and the third thickness. In the embodiments, the third thickness is thicker than the first thickness and the second thickness. In some embodiments, the first thickness is about 7 to 9 nm. In some embodiments, the second thickness is about 1 to 3 nm. In some embodiments, the third thickness is about 9 to 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.

[0064] Referring to FIG. 5c, embodiments of the present disclosure include the step of oxidizing the top surface of a first tungsten portion (291) having a first thickness or the top surface (251) of a tungsten layer (231), the top surface of a second tungsten portion (292) having a second thickness on a sidewall (220), and the top surface of a third tungsten portion (293) to form a first oxidized tungsten portion (254) on a substrate field, a second oxidized tungsten portion (256) on a sidewall (220), and a third oxidized tungsten portion (258) on a dielectric bottom surface or tungsten deposited on a dielectric bottom surface. In the embodiments, plasma and oxygen are applied under conditions sufficient to partially convert the tungsten of the first and third portions into tungsten oxide while completely converting the tungsten on the sidewall (220) into tungsten oxide. In the embodiments, the first tungsten portion is converted more into tungsten oxide than the third tungsten portion. In the embodiments, the present disclosure includes the step of pre-selecting or tuning the thickness of the first oxidized tungsten portion (254) while limiting the thickness of the third oxidized tungsten portion (258) on the dielectric bottom surface or the tungsten deposited on the dielectric bottom surface.

[0065] In the embodiments, after forming a first oxidized tungsten portion (254) on the substrate field, a second oxidized tungsten portion (256) on the sidewall (220), and a third oxidized tungsten portion (258) on the tungsten deposited on the dielectric bottom surface or on the dielectric bottom, the substrate (200) may be further processed to form a structure as shown in FIG. 5e. For example, in some embodiments, tungsten hexafluoride (WF6) is provided in an amount sufficient to immerse the structure shown in FIG. 5c and remove all tungsten oxide from the sidewall (220). As shown in FIG. 5c and FIG. 5d, at least a portion of the third tungsten portion (293) remains on the dielectric bottom surface (222). After further etching, and as shown in FIG. 5e, no tungsten remains on the substrate field (225) and the sidewall (220). In the embodiments, examples of reducing gases may include hydrogen gas and NH3 gas. In the embodiments, hydrogen gas and NH3 gas may be used alone or as a mixture thereof. In these embodiments, the reducing gas containing WF6 is used alone.

[0066] Tungsten-containing layers demonstrate utility when tungsten layers as described above are integrated with conventional filling techniques to form features having excellent film properties. The integration method may include physical vapor deposition (PVD) and plasma enhancement for depositing the tungsten layer. Etching chambers are 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 are included and are each available from Applied Materials, Inc., located in Santa Clara, California. In one embodiment, a physical vapor deposition (PVD) and etching chamber is provided to perform all vapor deposition and etching processes associated with a tungsten layer on a dielectric layer.

[0067] Now, referring to FIG. 6, the methods described herein may be performed in individual process chambers that may be provided as a standalone configuration or as part of one or more cluster tools, for example, an integrated tool (600) (i.e., cluster tool) described below in relation to FIG. 6. In embodiments, the cluster tool is configured to perform methods such as a method (100) for selectively depositing a tungsten layer on a dielectric surface, and the method (100) for selectively depositing a tungsten layer on a dielectric surface comprises: (a) a step of depositing a tungsten layer on a substrate field and on the sidewalls of a feature placed on the substrate and on the dielectric bottom surface through a physical vapor deposition (PVD) process to form a first tungsten portion having a first thickness on the substrate field, 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 is smaller than the first thickness and the third thickness —; (b) a step of oxidizing the top surface of a tungsten layer to form a first oxidized tungsten portion on a substrate field, a second oxidized tungsten portion on a sidewall, and a third oxidized tungsten portion on a dielectric bottom surface; (c) a step of removing the first oxidized tungsten portion, the second oxidized tungsten portion, and the third oxidized tungsten portion ― the second tungsten portion is completely removed from the sidewall ―; and (d) a step of passivating the first tungsten portion or completely removing it from the substrate field.

[0068] In the embodiments, the cluster tool may 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., Santa Clara, California. Examples of the integrated tool (600) include CENTURA® and ENDURA® integrated tools available from Applied Materials, Inc., Santa Clara, California. However, the methods described herein may be carried out using other cluster tools in which suitable process chambers are combined, or in other suitable process chambers. For example, in some embodiments, the methods of the invention discussed above may be carried out in an integrated tool such that vacuum breakdowns during processing are limited or non-existent, which is advantageous.

[0069] In the embodiments, the integration tool (600) may include two load lock chambers (606A, 606B) for transferring substrates into and out of the integration tool (600). Generally, because the integration tool (600) is under vacuum, the load lock chambers (606A, 606B) can "pump down" the substrates introduced into the integration tool (600). The first robot (410) can transfer substrates between the load lock chambers (606A, 606B) and one or more substrate processing chambers (612, 614, 616, 618) (four are shown) of a first set coupled to the first central transfer chamber (650). Each substrate processing chamber (612, 614, 616, 618) may be equipped to perform a number of substrate processing operations. In some embodiments, one or more substrate processing chambers (612, 614, 616, 618) of the first set may include any combination of PVD, etching, ALD, CVD, or degassing chambers. For example, in some embodiments, the substrate processing chambers (612, 614) include a process chamber suitable for PVD deposition configured to deposit tungsten on a substrate as described above.

[0070] In some embodiments, the first robot (610) may also transfer substrates to / from two intermediate transfer chambers (622, 624). The intermediate transfer chambers (622, 624) may be used to maintain ultra-high vacuum conditions while allowing substrates to be transferred within the integration tool (600). The second robot (630) may 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 the second central transfer chamber (655). Substrate processing chambers (632, 634, 635, 636, 638) may be equipped to perform various substrate processing operations including the methods (300, 400) described above, in addition to physical vapor deposition (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) may be removed from the integration tool (600) if they are not required for a specific process to be performed by the integration tool (600). In embodiments, the microprocessor includes a memory, such as a non-transient computer-readable medium, which stores instructions that, when executed, cause the integration tool or reaction chamber to perform a method of selectively depositing a tungsten layer on a dielectric surface according to the present disclosure.

[0071] In some embodiments, the present disclosure relates to a non-transient computer-readable medium storing instructions that, when executed, cause a reaction chamber to perform a method of selectively depositing a tungsten layer on a dielectric surface, wherein the method of selectively depositing a tungsten layer on a dielectric surface comprises: (a) a step of depositing a tungsten layer on a substrate field and on the sidewalls of a feature disposed on the substrate and on the dielectric bottom surface through a physical vapor deposition (PVD) process to form a first tungsten portion having a first thickness on the substrate field, 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 is smaller than the first thickness and the third thickness —; (b) a step of oxidizing the top surface of the tungsten layer to form a first oxidized tungsten portion on the substrate field, a second oxidized tungsten portion on the sidewalls, and a third oxidized tungsten portion on the dielectric bottom surface; (c) a step of removing the first oxidized tungsten portion, the second oxidized tungsten portion, and the third oxidized tungsten portion — the second tungsten portion is completely removed from the sidewall —; and (d) a step of passivating the first tungsten portion or completely removing it from the substrate field.

[0072] In some embodiments, the present disclosure relates to a non-transient computer-readable medium storing instructions that, when executed, cause a reaction chamber to perform a method of selectively depositing a tungsten layer on a dielectric surface, wherein the method of selectively depositing a tungsten layer on a dielectric surface comprises: (a) a step of depositing a tungsten layer on a substrate field and on a sidewall of a feature disposed on the substrate and on a dielectric bottom surface through a physical vapor deposition (PVD) process to form a first tungsten portion having a first thickness on the substrate field, a second tungsten portion having a second thickness on the sidewall, and a third tungsten portion having a third thickness on the dielectric bottom surface — the second thickness is smaller than the first thickness and the third thickness —; and (b) a step of removing the first tungsten portion and the second tungsten — the second tungsten portion is completely removed from the sidewall; and the third tungsten portion remains on the dielectric bottom surface —.

[0073] In some embodiments, the present disclosure relates to a method for selectively depositing a tungsten layer on a dielectric surface, wherein the method for selectively depositing a tungsten layer on a dielectric surface comprises: (a) depositing a tungsten layer on a substrate field and on the sidewalls of a feature disposed on the substrate and on the dielectric bottom surface through a physical vapor deposition (PVD) process to form a first tungsten portion having a first thickness on the substrate field, 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 is smaller than the first thickness and the third thickness —; (b) oxidizing the top surface of the tungsten layer to form a first oxidized tungsten portion on the substrate field, a second oxidized tungsten portion on the sidewalls, and a third oxidized tungsten portion on the dielectric bottom surface; (c) a step of removing a first oxidized tungsten portion, a second oxidized tungsten portion, and a third oxidized tungsten portion—the second tungsten portion is completely removed from the sidewall—; and (d) a step of passivating the first tungsten portion or completely removing it from the substrate field. In the embodiments, steps (a), (b), (c), and (d) are performed sequentially. In the embodiments, steps (b) and (c) are repeated periodically for a number of cycles sufficient to remove the first tungsten portion from the field of the substrate, wherein the third oxidized tungsten portion remains on the dielectric bottom surface. In some embodiments, the deposition comprises forming a first thickness and a third thickness greater than the second thickness. In the embodiments, the oxidation is characterized as conformal or super-conformal. In the embodiments, the oxidation comprises contacting the top surface of the tungsten layer with an oxygen plasma.In the embodiments, removal comprises contacting the first oxidized tungsten portion, the second oxidized tungsten portion, and the third oxidized tungsten portion with WF6 under conditions sufficient to remove the second oxidized tungsten portion from the sidewall. In the embodiments, passivating comprises contacting the first tungsten portion with a remote nitrogen plasma at a temperature of about 300°C to about 400°C and a pressure of about 500 mTorr to about 1 Torr, wherein the 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 a capacitively coupled plasma containing oxygen at a temperature of about 300°C to about 400°C.

[0074] In some embodiments, a method for selectively depositing a tungsten layer on a dielectric surface comprises: (a) depositing a tungsten layer on a substrate field and on the sidewalls of a feature disposed on the substrate and on the dielectric bottom surface via a physical vapor deposition (PVD) process to form a first tungsten portion having a first thickness on the substrate field, 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 is smaller than the first thickness and the third thickness —; and (b) removing the first tungsten portion and the second tungsten — the second tungsten portion is completely removed from the sidewalls; and the third tungsten portion remains on the dielectric bottom surface —. In some embodiments, the deposition comprises forming a first thickness and a third thickness greater than the second thickness. In some embodiments, the removal further comprises bringing the substrate into contact with WF6 under conditions sufficient to remove tungsten from the sidewalls.

[0075] In some embodiments, the present disclosure relates to a method for selectively depositing a tungsten layer on a dielectric surface, wherein the method for selectively depositing a tungsten layer on a dielectric surface comprises: (a) depositing a tungsten layer on a substrate field and on the sidewalls of a feature disposed on the substrate and on the dielectric bottom surface through a physical vapor deposition (PVD) process to form a first tungsten portion having a first thickness on the substrate field, 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 is smaller than the first thickness and the third thickness —; (b) oxidizing the top surface of the tungsten layer to form a first oxidized tungsten portion on the substrate field, a second oxidized tungsten portion on the sidewalls, and a third oxidized tungsten portion on the dielectric bottom surface; (c) a step of removing a first oxidized tungsten portion, a second oxidized tungsten portion, and a third oxidized tungsten portion — the second tungsten portion is completely removed from the sidewall —; and (d) a step of passivating the first tungsten portion or completely removing it from the substrate field. In some embodiments, the first thickness is about 7 to 9 nm, the second thickness is about 1 to 3 nm, and the third thickness is about 9 to 11 nm. In some embodiments, the deposition comprises forming a first thickness and a 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 oxidized tungsten portion has a thickness of about 3 to 7 nm. In some embodiments, the second oxidized tungsten portion has a thickness equal to the second thickness or the thickness of the second tungsten portion, and may have a thickness such as about 1 to 3 nm. In some embodiments, the third oxidized tungsten portion has a thickness of about 3 to 7 nm, such as about 5, 6, or 7 nm.

[0076] In some embodiments, the present disclosure relates to a method for selectively depositing a tungsten layer on a dielectric surface, wherein the method for selectively depositing a tungsten layer on a dielectric surface comprises: (a) a step of depositing a tungsten layer on a substrate field and on the sidewalls of a feature disposed on the substrate and on the dielectric bottom surface through a physical vapor deposition (PVD) process to form a first tungsten portion having a first thickness on the substrate field, 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 smaller than the first thickness and the third thickness—; and (b) a step of removing the first tungsten portion and the second tungsten portion—the first tungsten portion and the second tungsten portion being completely removed from the substrate, and the third tungsten portion remaining on the dielectric bottom surface. In embodiments, the first thickness is smaller than the third thickness. In the embodiments, the deposition further comprises forming a first thickness smaller than a third thickness. In the embodiments, the deposition further comprises forming a first thickness and a third thickness larger than a second thickness. In the embodiments, the first thickness is about 7 to 9 nm. In the embodiments, the second thickness is about 1 to 3 nm. In the embodiments, the third thickness is about 9 to 11 nm. In the embodiments, the first thickness is about 8 nm, the second thickness is about 2 nm, and the third thickness is about 10 nm.

[0077] Although the foregoing relates to embodiments of the present disclosure, other and additional embodiments of the present disclosure may be devised without departing from the basic scope of the present disclosure.

Claims

Claim 1 A method for selectively depositing a tungsten layer atop a dielectric surface, comprising: (a) depositing a tungsten layer on a substrate field and on the sidewalls of a feature disposed on the substrate and on the dielectric bottom surface through a physical vapor deposition (PVD) process to form a first tungsten portion having a first thickness on the substrate field, 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 —; and (b) conformally oxidizing the top surface of the tungsten layer to form a first oxidized tungsten portion on the substrate field, a second oxidized tungsten portion on the sidewall, and a third oxidized tungsten portion on the dielectric bottom surface; (c) removing the first oxidized tungsten portion, the second oxidized tungsten portion, and the third oxidized tungsten portion — the second tungsten portion is completely removed from the substrate, and the third tungsten portion remains on the dielectric bottom surface —; and (d) passivating the first tungsten portion or completely removing it from the substrate field, comprising a method for selectively depositing a tungsten layer on a dielectric surface. Claim 2 A method for selectively depositing a tungsten layer on a dielectric surface, wherein, during step (c), the first tungsten portion is completely removed from the substrate. Claim 3 A method for selectively depositing a tungsten layer on a dielectric surface, wherein the step of oxidizing the top surface of the tungsten layer comprises the step of contacting the top surface of the tungsten layer with an oxygen plasma. Claim 4 A method for selectively depositing a tungsten layer on a dielectric surface, wherein the oxidizing step further comprises the step of providing a capacitance-coupled plasma containing oxygen at a temperature of 300 to 400 degrees Celsius. Claim 5 A method for selectively depositing a tungsten layer on a dielectric surface, wherein the removing step comprises contacting the first oxidized tungsten portion, the second oxidized tungsten portion, and the third oxidized tungsten portion with WF6 under conditions sufficient to remove the second oxidized tungsten portion from the sidewall. Claim 6 A method for selectively depositing a tungsten layer on a dielectric surface, wherein, in claim 1, the first tungsten portion is passivated, and the passivation comprises contacting the first tungsten portion with a remote nitrogen plasma at a temperature of 300 to 400 degrees Celsius, and the nitrogen is provided at a flow rate of 0.5 to 5 sccm or less than 5 sccm. Claim 7 A method for selectively depositing a tungsten layer on a dielectric surface, wherein the passivating comprises contacting the first tungsten portion with a remote nitrogen plasma at a pressure of 500 mTorr to 1 Torr, and the nitrogen is provided at a flow rate of 0.5 to 5 sccm or less than 5 sccm. Claim 8 A method for selectively depositing a tungsten layer on a dielectric surface, wherein, in any one of claims 1 to 7, steps (b) and (c) are periodically repeated in cycles sufficient to remove the first tungsten portion from the substrate field, and the third oxidized tungsten portion remains on the dielectric bottom surface. Claim 9 A method for selectively depositing a tungsten layer on a dielectric surface, wherein, in any one of claims 1 to 7, the first thickness is 7 to 9 nm; the second thickness is 1 to 3 nm; or the third thickness is 9 to 11 nm. Claim 10 A method for selectively depositing a tungsten layer on a dielectric surface, wherein, in any one of claims 1 to 7, the first thickness is smaller than the third thickness. Claim 11 A non-transient computer-readable medium having stored instructions, wherein, when executed, the instructions cause a reaction chamber to perform a method of selectively depositing a tungsten layer on a dielectric surface, said method being the method described in any one of claims 1 to 7. Claim 12 delete Claim 13 delete

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