Method for selective deposition of tungsten for bottom-up gap fill over dielectric layers
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- APPLIED MATERIALS INC
- Filing Date
- 2021-04-08
- Publication Date
- 2026-06-23
Smart Images
Figure CN115039210B_ABST
Abstract
Description
Technical Field
[0001] Embodiments of this disclosure generally relate to methods for selectively depositing tungsten on top of a dielectric layer. Background Technology
[0002] The continuous reduction in the size of semiconductor device geometries has enabled semiconductor manufacturing equipment to produce devices with feature sizes smaller than 30 nm, and new equipment is being developed and implemented to fabricate devices with even smaller geometries. The reduced feature size leads to a decrease in the spatial dimensions of structural features on the device. The width of gaps and trenches on the device is narrowing to the point where the aspect ratio of gap depth to width becomes sufficiently high, making it challenging to fill the gaps with material. Before the gaps are fully filled, the deposited material is prone to clogging on top, creating pores or gaps in the middle of the gaps.
[0003] Interstitial filling deposition of tungsten films using chemical vapor deposition (CVD) is an integral part of numerous semiconductor manufacturing processes. Tungsten films can be used for low-resistivity electrical connections in the form of horizontal interconnects, vias between adjacent metal layers, and contacts between devices on a first metal layer and a silicon substrate. In conventional tungsten deposition processes, the wafer is heated to processing temperature in a vacuum chamber, and a tungsten film (the host layer) is deposited on a nucleation layer. The inventors have discovered that, regardless of the conformal nature of the CVD host layer tungsten deposition, trenches can problematically promote the formation of enclosed pockets in the interstitial filling tungsten.
[0004] Physical vapor deposition (PVD) technology is known, but the inventors have observed that gap-filling problems persist 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 typically deposits a non-selective blanket layer of material onto the substrate that is not used for continuous selective deposition. The inventors have also observed that PVD deposition of tungsten on top of non-conductive surfaces (such as dielectric materials) is problematic.
[0005] Selective deposition processes can advantageously reduce the number of steps and cost involved in conventional photolithography while maintaining the pace of device size reduction. Since tungsten is a widely used material for reducing contact resistance in transistor connections, selective deposition in tungsten integration schemes has high potential value. The inventors observed that the poor selectivity of tungsten between silicon and dielectrics (such as silicon nitride and silicon oxide) poses a significant challenge to maximizing metal feature filling. For example, poor selectivity can lead to tungsten deposition on the sidewalls and bottom of high aspect ratio features and limit the ability to fill features with the desired metal material. Because poor selectivity can promote substrate inhomogeneity, highly selective deposition of tungsten is required to reduce contact resistance and maximize the volume of feature fill material.
[0006] Therefore, the inventors have developed an improved method for selectively depositing tungsten materials onto dielectrics such as silicon oxide, silicon nitride, and tetraethyl orthosilicate (TEOS). Summary of the Invention
[0007] This document provides a method and apparatus for selectively depositing a tungsten layer on top of a dielectric surface. In some embodiments, a method for selectively depositing a tungsten layer on top of a dielectric surface includes: (a) depositing a tungsten layer on top of a substrate field and on top of characteristic sidewalls and a dielectric bottom surface disposed in the substrate via a physical vapor deposition (PVD) process to form a first tungsten portion having a first thickness on top of the substrate field, a second tungsten portion having a second thickness on top of the sidewalls, and a third tungsten portion having a third thickness on top of 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 oxidized tungsten portion on top of the substrate field, a second oxidized tungsten portion on top of the sidewalls, and a third oxidized tungsten portion on top of the dielectric bottom surface; (c) removing the first oxidized tungsten portion, the second oxidized tungsten portion, and the third oxidized tungsten portion, wherein the second tungsten portion is completely removed from the sidewalls; and (d) passivating or completely removing the first tungsten portion from the substrate field. In one embodiment, the first tungsten oxide portion on top of the substrate field is thicker than the third tungsten oxide portion on top of the dielectric substrate surface. In another embodiment, maintaining the third tungsten portion, or a portion thereof, on top of the dielectric substrate surface promotes selective tungsten growth.
[0008] In some embodiments, a method for selectively depositing a tungsten layer on top of a dielectric bottom surface includes: (a) depositing a tungsten layer on top of a substrate field and on top of characteristic sidewalls and the dielectric bottom surface disposed in the substrate via a physical vapor deposition (PVD) process to form a first tungsten portion having a first thickness on top of the substrate field, a second tungsten portion having a second thickness on top of the sidewalls, and a third tungsten portion having a third thickness on top of 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 first tungsten portion and the second tungsten portion are completely removed from the substrate, and wherein the third tungsten portion remains on top of the dielectric bottom surface. In embodiments, the first thickness is less than the third thickness.
[0009] In some embodiments, this disclosure relates to a non-transitory computer-readable medium having instructions stored thereon that, when executed, cause a reaction chamber to perform a method of selectively depositing a tungsten layer on top of a dielectric surface, comprising: (a) depositing a tungsten layer on top of a substrate field and on top of characteristic sidewalls and a dielectric bottom surface disposed in the substrate via a physical vapor deposition (PVD) process to form a first tungsten portion having a first thickness on top of the substrate field, a second tungsten portion having a second thickness on top of the sidewalls, and a third tungsten portion having a third thickness on top of 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 oxidized tungsten portion on top of the substrate field, a second oxidized tungsten portion on top of the sidewalls, and a third oxidized tungsten portion on top of the dielectric bottom surface; (c) removing the first oxidized tungsten portion, the second oxidized tungsten portion, and the third oxidized tungsten portion, wherein the second tungsten portion is completely removed from the sidewalls; and (d) passivating or completely removing the first tungsten portion from the substrate field.
[0010] In some embodiments, this disclosure relates to a non-transitory computer-readable medium having instructions stored thereon that, when executed, cause a reaction chamber to perform a method of selectively depositing a tungsten layer on top of a dielectric surface, comprising: (a) depositing a tungsten layer on top of a substrate field and on top of characteristic sidewalls and a dielectric bottom surface disposed in the substrate via a physical vapor deposition (PVD) process to form a first tungsten portion having a first thickness on top of the substrate field, a second tungsten portion having a second thickness on top of the sidewalls, and a third tungsten portion having a third thickness on top of 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 first tungsten portion and the second tungsten portion are completely removed from the substrate, and wherein the third tungsten portion remains on top of the dielectric bottom surface.
[0011] Other and further embodiments of this disclosure are described below. Attached Figure Description
[0012] The embodiments of this disclosure, which have been briefly summarized above and discussed in more detail below, can be understood by referring to the illustrative embodiments of this disclosure depicted in the accompanying drawings. However, the drawings only show typical embodiments of this disclosure and are therefore not to be considered as limiting the scope, as this disclosure allows for other equivalent and effective embodiments.
[0013] Figure 1 The illustration is a flowchart of a method for selectively depositing a tungsten layer on top of a dielectric surface according to an embodiment of the present disclosure.
[0014] Figures 2A to 2E The diagrams are respectively based on, for example, the contents of this disclosure. Figure 1 The implementation method involves the stage of selectively depositing a tungsten layer on top of a dielectric surface.
[0015] Figures 3A to 3E The illustrations depict the stages of selectively depositing a tungsten layer on top of a dielectric surface according to embodiments of the present disclosure.
[0016] Figures 4A to 4D The illustrations depict the stages of selectively depositing a tungsten layer on top of a dielectric surface according to embodiments of the present disclosure.
[0017] Figures 5A to 5E The illustrations depict the stages of selectively depositing a tungsten layer on top of a dielectric surface according to embodiments of the present disclosure.
[0018] Figure 6 The illustration shows a cluster tool suitable for performing a method of processing a substrate according to some embodiments of the present disclosure.
[0019] Figure 7 The illustration is a flowchart of a method for selectively depositing a tungsten layer on top of a dielectric surface according to an embodiment of the present disclosure.
[0020] For ease of understanding, the same reference numerals have been used to identify common elements in the figures where possible. The figures are not drawn to scale and have been simplified for clarity. Elements and features of one embodiment may be advantageously incorporated into other embodiments without further description. Detailed Implementation
[0021] The inventors have observed that, according to this disclosure, tungsten deposited within a feature can advantageously be selectively formed directly on top of the dielectric layer. This selective deposition of tungsten directly on top of the dielectric layer advantageously provides bottom-up gap filling, thereby reducing or eliminating the formation of porosity or gaps within the feature. During the formation of a semiconductor device, reducing or eliminating porosity within the feature decreases resistance, leading to increased device yield, lower manufacturing costs, and providing increased uniformity across multiple features. This increased uniformity enhancement is further amplified by the application of additional processing layers as manufacturing continues.
[0022] Figure 1 This is a flowchart of a method 100 for selectively depositing a tungsten layer on top of a dielectric surface according to some embodiments of this disclosure. (See also...) Figures 2A to 2E The method 100 described below with respect to the stage of processing a substrate is illustrated herein. The method described herein can be performed in a separate processing chamber, such as a physical vapor deposition (PVD) chamber or etching chamber that can be constructed independently or provided as part of one or more cluster tools, such as… Figure 6 The integrated tool 600 shown (i.e., cluster tool) or chambers such as those available from Applied Materials, Inc., Santa Clara, CA. Other processing chambers (including those available from other manufacturers) may also be adapted to benefit from this disclosure.
[0023] Method 100 is typically performed on a substrate 200 that provides processing space to the processing chamber. In some embodiments, such as Figure 2A As shown, the substrate 200 includes one or more features, such as trenches 210 selectively filled with a tungsten layer 231. Figures 2A to 2E As shown in the diagram, trench 210 extends toward the substrate 214 of substrate 200. Although the following description pertains to one feature, substrate 200 may include any number of features described below (such as multiple trenches 210, vias, self-aligned vias, self-aligned contact features, dual damascene structures, and the like) or may be suitable for use in multiple processing applications, such as dual damascene fabrication processes, self-aligned contact feature processing, and the like. Non-limiting examples of features suitable for etching according to this disclosure include trenches (such as trench 210), vias, and dual damascene type features.
[0024] In embodiments, substrate 200 may be formed of or include one or more of the following: silicon (Si), silicon oxide (such as silicon monoxide (SiO) or silicon dioxide (SiO2)), silicon nitride (such as SiN), or the like. In non-limiting embodiments, substrate 200 may have trenches 210 formed in a dielectric layer, thus the dielectric layer may be substrate 200 or made of the same materials as described above, such as SiN, SiO, and the like. In embodiments, low dielectric constant dielectric materials may be suitable for use as substrate 200 or its layers (e.g., materials having a dielectric constant less than silicon oxide or less than about 3.9), or the like. Furthermore, substrate 200 may include additional material layers or may have one or more structures or means formed, completed or partially completed, in, above, or below substrate 200 (not shown). In some embodiments, substrate 200 or one or more layers thereof may include, for example, a doped or undoped silicon substrate, a III-V compound substrate, a silicon-germanium (SiGe) substrate, an epitaxial substrate, a silicon-on-insulator (SOI) substrate, a display substrate (such as a liquid crystal display (LCD), a plasma display, an electroluminescence (EL) lamp display), a light-emitting diode (LED) substrate, a solar cell array, a solar panel, or the like. In some embodiments, substrate 200 includes a semiconductor wafer. In some embodiments, the material of substrate 200 at the bottom of trench 210 is a dielectric material extending across the bottom of trench 210.
[0025] In this embodiment, the substrate 200 may not be limited to any size or shape. The substrate 200 may be a circular wafer having a diameter of 200 mm, 300 mm, or other diameters (such as 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 trench 210) can be formed by etching substrate 200 using any suitable etching process. In embodiments, suitable features as used according to this disclosure include one or more trenches with a high depth-to-width ratio, the trenches having a width of less than 20 nanometers. In some embodiments, trench 210 is defined by substrate field 225, sidewalls 220, a dielectric bottom surface 222 of the feature (such as trench 210), and an upper corner 224 disposed in substrate 200. In some embodiments, trench 210 may have a high depth-to-width ratio, for example, between about 5:1 and about 20:1. As used herein, depth-to-width ratio is the ratio of the depth of a feature to the width of the feature. In embodiments, trench 210 has a width less than or equal to 20 nanometers, less than or equal to 10 nanometers as indicated by arrow 226, or a width between 5 and 10 nanometers as indicated by arrow 226.
[0027] See Figure 2B In some embodiments, the substrate 200 includes or is composed of a dielectric layer of the material described above, such as silicon oxide, silicon monoxide (SiO), silicon dioxide (SiO2), silicon nitride (such as SiN), tetraethyl orthosilicate (TEOS), or the like, and is shaped to have an opening 221 in the substrate field 225, a surface opposite to the opening 221 (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 to the opening 211.
[0028] See now Figure 1 102 places, and Figure 2BMethod 100 includes depositing a tungsten layer 231 via a physical vapor deposition (PVD) process on top of a substrate field 225, on top of a sidewall 220, and on top of a dielectric bottom surface 222 of a feature (such as trench 210) disposed in a substrate 200. This forms a first tungsten portion having a first thickness on top of the substrate field 225, a second tungsten portion having a second thickness on top of the sidewall 220, and a third tungsten portion having a third thickness on top of the dielectric bottom surface 222, wherein the second thickness is less than the first and third thicknesses. For example, in some embodiments, in a processing chamber configured to deposit the tungsten layer 231 via PVD, the tungsten layer 231 is deposited on the substrate 200 and within a feature (such as trench 210). In one embodiment, the tungsten layer 231 may be a layer nonconformally formed on top of the substrate field 225 along the sidewall 220 of a feature (such as trench 210) and the dielectric bottom surface 222, such that the substantial portion of the feature prior to the deposition layer remains unfilled after the deposition layer, wherein a first tungsten portion having a first thickness (as shown by arrow 236) (illustrated by arrow 235) is disposed on top of the substrate field 225 or directly on top of the substrate field 225, a second tungsten portion having a second thickness (as shown by arrow 238) (adjacent to arrow 237) is disposed on top of the sidewall 220 or directly on top of the sidewall 220, and a third tungsten portion having a third thickness (as shown by arrow 240) (illustrated above arrow 239) is disposed on top of the dielectric bottom surface 222 or directly on top of the dielectric bottom surface 222, wherein the second thickness (as shown by arrow 238) is less than the first thickness (as shown by arrow 236) and the third thickness (as shown by arrow 240). Figure 2B It was not drawn to scale. Figure 2B It is not drawn to scale, and in the implementation, the first thickness, the second thickness, and the third thickness are not equal.
[0029] In some embodiments, the tungsten layer 231 may be formed along the entire sidewall 220 (such as both sidewalls) and the dielectric bottom surface 222 of the trench 210. In some embodiments, the PVD chamber is configured to deposit a tungsten layer thinner than the substrate field 225 or the dielectric bottom surface 222 on the sidewall 220. For example, in some embodiments, a first tungsten portion (as shown by arrow 235) has a first thickness of 3 to 6 nm (as shown by arrow 236), a second tungsten portion has a second thickness different from the first thickness and is disposed on top of the sidewall 220, and a third tungsten portion (as shown by arrow 239) has a third thickness of 3 to 6 nm (as shown by arrow 240). In embodiments, the first and third thicknesses are thicker than the thickness of the second tungsten portion on top of the sidewall 220. In embodiments, the second tungsten portion has a second thickness of 0.5 to 1.5 nm, such as about 1 nm. In embodiments, the first thickness is less than the third thickness. In embodiments, the first and third thicknesses are each greater than the second thickness. In one embodiment, the first thickness is about 7 to 9 nm. In another embodiment, the second thickness is about 1 to 3 nm. In yet another embodiment, the third thickness is about 9 to 11 nm. In yet another embodiment, 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 gaps in the feature, such as trenches, vias, self-aligned vias, dual damascene structures, or the like. In some embodiments, the shape of the tungsten layer 231 fills the feature from the bottom portion adjacent to the dielectric base surface 222. In some embodiments, the feature fills only about 5% to 25% of the area above the dielectric base surface 222, such as about 10%, 15%, or 20%.
[0031] See also Figure 2B The tungsten layer 231 is illustrated as being PVD deposited on top of the substrate 200 and within features (such as trenches 210). In some embodiments, the tungsten layer 231 comprises tungsten or a tungsten alloy. However, in some embodiments, 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 some embodiments, the tungsten and tungsten-containing materials are substantially pure tungsten, or tungsten having no more than 1, 2, 3, 4, or 5% impurities.
[0032] In some implementations, such as Figure 2BAs shown, a tungsten layer 231 is deposited on top of the dielectric bottom surface 222 of the substrate 200 and within a trench 210 formed in the substrate 200. The tungsten layer 231 can be deposited using any PVD system available from Applied Materials, Inc., Santa Clara, CA. Other suitable PVD processing chambers can be used similarly. In some embodiments, suitable processing conditions for PVD deposition of the tungsten layer 231 include processing conditions such as a temperature suitable for heating the substrate in the range of about 450 degrees Celsius to about 600 degrees Celsius, or in the range of about 450 degrees Celsius to about 500 degrees Celsius. In embodiments, the processing chamber for tungsten deposition is maintained at a pressure in the range of about 1 Torr to about 150 Torr, or at a pressure in the range of about 5 Torr to about 90 Torr.
[0033] See Figure 1 At location 104, embodiments of this disclosure include forming a first oxidized tungsten portion 254 on the top surface 251 of the tungsten oxide layer 231, a second oxidized tungsten portion 256 on the top of the sidewall 220, and a third oxidized tungsten portion 258 on the top of the dielectric bottom surface. In an embodiment, tungsten portions sufficient to convert the first and third tungsten portions into tungsten oxide (WO3). x Simultaneously, plasma and oxygen are applied under conditions where the second tungsten portion on top of the sidewall 220 is completely converted into tungsten oxide. In this embodiment, the first tungsten portion (in...) Figure 2B As shown by arrow 235, the portion is converted into tungsten oxide, for example, the length across the first tungsten portion from top to bottom, and the third tungsten portion (in...) Figure 2B As shown by arrow 239, the portion of the first portion is converted to tungsten oxide, for example, the length of the first portion from top to bottom, while the second tungsten portion on top of the sidewall 220 is completely converted to tungsten oxide.
[0034] In some embodiments, the first tungsten portion (as shown by arrow 235), the second tungsten portion (near arrow 237), and the third tungsten portion (as shown by arrow 239) are each partially or completely oxidized by a free radical oxidation process, wherein a sufficient amount of oxygen is provided to the substrate to contact the tungsten portion disposed thereon. In some embodiments, the second tungsten portion (near arrow 237) on the top of the sidewall 220 is provided sufficiently to oxidize to form tungsten oxide (WO3) on the substrate surface. x The amount of oxygen flux.
[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 or equal to the second thickness, 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, the oxidation process is performed on substrate 200 using oxygen free radicals in a processing chamber to form Figure 2C The structure shown has a substrate with a first tungsten portion (as indicated by arrow 235), a second tungsten portion (near arrow 237), and a third tungsten portion (as indicated by arrow 239). In the embodiment, oxygen and argon are applied to the substrate. Plasma power is applied to the gases to generate oxygen free radicals, etc. The free radicals are associated with the substrate 200 and the first tungsten portion (as indicated by arrow 235), the second tungsten portion (near arrow 237), and the third tungsten portion (near arrow 239). Figure 2B (near arrow 237), and the third tungsten portion (in Figure 2B As shown by arrow 239, the reaction forms an oxide layer 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 some embodiments, the oxidation process can 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 (as shown by arrow 235), a second tungsten portion (near arrow 237), and a third tungsten portion (as shown by arrow 239) is loaded into a chamber. The pressure and temperature within the chamber are controlled to stabilize the chamber. An inert gas may be introduced into the chamber to regulate the pressure. 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 for generating plasma in the chamber is applied to the chamber. In 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 an oxidation process is provided to the chamber using a continuously applied plasma power. In some embodiments, the pressure is about 1 mTorr to 100 mTorr. In some embodiments, oxygen is introduced into the chamber to perform the main oxidation process while the chamber is maintained at this pressure. Alternatively, an inert gas (such as argon) may be introduced into the chamber along with oxygen. In some embodiments, argon gas is included and used to rapidly generate plasma. In some embodiments, an oxygen flux is provided sufficient to completely oxidize all the tungsten disposed above the sidewalls 220 of the tungsten layer pattern and to partially oxidize a first tungsten portion on top of the substrate field 225 (as indicated by arrow 235) and a third tungsten portion on top of the dielectric substrate surface 222 (as indicated by arrow 239) to form tungsten oxide (WO3). x (where x is an integer). In an embodiment, the first tungsten portion (as shown by arrow 235) and the third tungsten portion (as shown by arrow 239) on top of the substrate field 225 are oxidized from top to bottom to a depth between 0.5 and 2.0 nm, or between about 1 and 1.5 nm.
[0038] Now refer to process column 106 of method 100 and... Figure 2C and Figure 2D This disclosure includes the removal of a first oxidized tungsten portion (illustrated below arrow 261), a second oxidized tungsten portion (illustrated adjacent to arrow 263), and a third oxidized tungsten portion (illustrated adjacent to arrow 262), wherein the second oxidized tungsten portion (illustrated adjacent to arrow 263) is completely removed from the sidewall. Therefore, by oxidizing all tungsten above sidewall 220 and removing all second oxidized tungsten, as... Figure 2D As shown, all tungsten is removed from sidewall 220. In the embodiment, see now. Figure 2D After the oxidation process, a reducing gas including tungsten hexafluoride (WF6) is introduced in situ into the chamber to reduce and remove tungsten oxide (WO3) from the sidewalls 220 of the tungsten layer pattern. x ), thus forming Figure 2D The structure shown does not have tungsten oxide on the sidewall 220. In some embodiments, it is provided to be sufficient for immersion. Figure 2D The structure shown removes an amount of tungsten hexafluoride (WF6) from the sidewall 220, removing all tungsten oxide. (As shown...) Figure 2D As shown, at least a portion of the third tungsten portion remains on top of the dielectric substrate surface 222, and at least a portion of the first tungsten portion remains on top of the substrate field 225. In embodiments, examples of reducing gases may include hydrogen and NH3 gas. In embodiments, hydrogen and NH3 gas may be used alone or in mixtures thereof. In this embodiment, a reducing gas comprising WF6 is used alone.
[0039] Now refer to process column 108 of method 100 and... Figure 2E This disclosure includes passivating the first tungsten portion or completely removing the first tungsten portion from the substrate field 225. For example, Figure 2EThe illustration illustrates passivating a first tungsten portion 273 on a substrate field 225 by forming a tungsten nitride layer 271 on or within the first tungsten portion 273 on top of the substrate field 225. In an embodiment, the tungsten nitride layer 271 is formed in a processing chamber via 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 mTorr to 1 Torr. In some embodiments, method 100 includes flowing reaction products from the remote plasma reaction into the processing chamber to selectively form the tungsten nitride layer 271 on the surface of the first tungsten portion 273. In an embodiment, the top surface 280 of the third tungsten portion does not contact the remote plasma or the reactants of the remote plasma and does not react with nitrogen. In an embodiment, the remote plasma reaction involves reacting nitrogen (N2) with argon (Ar) at a first temperature of 300 to 400 degrees Celsius. In some embodiments, approximately 65 watts of RF energy is applied to the remote plasma reaction. In an embodiment, a tungsten nitride layer 271 is deposited to a predetermined thickness, such as about 10 angstroms to about 100 angstroms, or about 100 angstroms to about 500 angstroms.
[0040] In some embodiments, the nitriding process train or direct plasma reaction of process train 108 provides nitrogen gas at a flow rate of about 5 sccm or less. In embodiments, the pressure in the processing chamber is maintained at 50 mTorr to 1 Torr during the direct plasma reaction. In embodiments, RF power at about 100 W to 1000 W is applied during the direct plasma reaction. In embodiments, the nitriding process is characterized as a weak nitrogen-based plasma that provides very little nitrogen gas to the process. Figure 2D The structure shown allows only the top surface of the tungsten deposited on the substrate field 225 to react with the nitrogen plasma. In this embodiment, 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] Figures 3A to 3EThe illustrations depict the stages of selectively depositing a tungsten layer on top of 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 top of a dielectric surface, comprising: depositing a tungsten layer on top of a substrate field and on top of characteristic sidewalls and a dielectric bottom surface disposed in the substrate via a physical vapor deposition (PVD) process to form a first tungsten portion having a first thickness on top of the substrate field, a second tungsten portion having a second thickness on top of the sidewalls, and a third tungsten portion having a third thickness on top of the dielectric bottom surface, wherein the second thickness is less than the first thickness and the third thickness; forming a first oxidized tungsten portion on top of the substrate field, a second oxidized tungsten portion on top of the sidewalls, and a third oxidized tungsten portion on top of the dielectric bottom surface on the top surface of a tungsten oxide layer; removing the first oxidized tungsten portion, the second oxidized tungsten portion, and the third oxidized tungsten portion, wherein the second tungsten portion is completely removed from the sidewalls; and removing the first tungsten portion from the substrate field.
[0042] Figure 3A The diagram illustrates the above text. Figure 2A The substrate 200 of the embodiment described herein. Figure 3B The illustration shows a PVD-deposited tungsten layer 231 on top of the substrate field 225, on top of the sidewall 220, and on top of the dielectric bottom surface 222 of features (such as trenches 210) provided in the substrate 200. This forms a first tungsten portion 291 with a first thickness on top of the substrate field 225, a second tungsten portion 292 with a second thickness on top of the sidewall 220, and a third tungsten portion 293 with a third thickness on top of the dielectric bottom surface 222. In this embodiment, the second thickness is less than the first and third thicknesses.
[0043] See Figure 3C Embodiments of this disclosure include forming a first tungsten oxide portion 254 on the top surface 251 of a tungsten oxide layer 231, a second tungsten oxide portion 256 on the top surface of a sidewall 220, and a third tungsten oxide portion 258 on the top surface of a dielectric substrate or on a tungsten substrate deposited on the dielectric substrate. In an embodiment, plasma and oxygen are applied under conditions sufficient to convert tungsten portions of the first and third tungsten portions into tungsten oxide, while completely converting the tungsten portion on the top surface of the sidewall 220 into tungsten oxide. In an embodiment, the first tungsten portion is converted into tungsten oxide more extensively than the third tungsten portion. In an embodiment, this disclosure includes pre-selecting or tuning the thickness of the first tungsten oxide portion 254 while limiting the thickness of the third tungsten oxide portion 258 on the top surface of the dielectric substrate 222 or on a tungsten substrate deposited on the dielectric substrate 222.
[0044] In some embodiments, the degree or thickness of tungsten oxidation can be tailored to provide improved etching performance by controlling dissociation and plasma characteristics. For example, in some embodiments, when a reduced-power capacitively-coupled plasma (CCP) is included in the processing chamber including substrate 200, chamber degradation can be reduced, thus providing an improved process. Therefore, the system described herein provides improved flexibility with regard to chemical modulation while also providing improved etching performance. In embodiments, a non-limiting processing chamber suitable for etching according to this disclosure is illustrated and described in U.S. Patent No. 9,362,130, entitled "Enhanced Etching Processes Using Remote Plasma Sources," issued June 7, 2016, to Ingle et al. and assigned to Applied Materials, Inc. In some embodiments, the processing chamber used herein is coupled to a remote plasma source that provides gaseous treatment radicals to the processing space. Typically, a remote plasma source (RPS) includes a capacitively-coupled plasma (CCP) source. In some embodiments, the remote plasma source is a stand-alone RPS unit. In other embodiments, the remote plasma source is a second processing chamber in fluid communication with a processing chamber including substrate 200.
[0045] In some embodiments, a remote plasma region in a processing chamber (such as an etching chamber) may be configured for capacitively coupled plasma (“CCP”) to be formed within the processing chamber region. In embodiments, the plasma configuration in the remote plasma region may be fluidly positioned between, for example, another remote plasma region and the 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 operate at reduced or substantially reduced power because the CCP may be used only to maintain the oxygen-containing plasma effluent and not to completely ionize the material within the plasma region. For example, the CCP may operate at power levels below or less than 400 W, 250 W, 200 W, 150 W, 100 W, 50 W, 20 W, etc., or even lower. Furthermore, the CCP may produce a flat plasma profile, which can provide a uniform plasma distribution within space. Therefore, a more uniform plasma can be delivered to the first tungsten portion 291, the second tungsten portion 292, but not to the third tungsten portion 293. Thus, the first tungsten portion 291 may undergo further oxidation or form a tungsten oxide layer therein that is thicker than that of the third tungsten portion 293. In an embodiment, the second tungsten portion 292 is thin and therefore completely converted into tungsten oxide.
[0046] In some embodiments, oxygen-containing plasma (such as CCP) can be delivered at a power of less than 400 W, for example, 350 W to 375 W. In some embodiments, CCP oxygen-containing plasma can be delivered at a temperature of about 300 degrees Celsius to about 400 degrees Celsius. In some embodiments, CCP oxygen-containing plasma can be delivered wherein oxygen is provided at a flow rate of less than 50 sccm (such as 30 to 45 sccm). In embodiments, CCP oxygen-containing plasma can be delivered for less than 60 seconds, less than 30 seconds, or between 10 and 25 seconds.
[0047] See Figure 3D This disclosure includes the removal of the first oxidized tungsten portion 254, the second oxidized tungsten portion 256, and the third oxidized tungsten portion 258, wherein the second tungsten portion 292 is completely removed from the sidewall 220. In an embodiment, the tungsten oxide is contacted with and immersed in tungsten hexafluoride (WF6) as described above. For example, see now. Figure 3D After the oxidation process, a reducing gas, including tungsten hexafluoride (WF6), is introduced in situ into the processing chamber (which includes a substrate 200) to reduce and remove tungsten oxide (WO3) from the sidewalls 220 of the tungsten layer pattern. x ), thus forming Figure 3D The structure shown does not have tungsten oxide on the sidewall 220. In some embodiments, it is provided to be sufficient for immersion. Figure 3D The structure shown removes all tungsten hexafluoride (WF6) oxide from sidewall 220. In some embodiments, as indicated by arrows 297 and 298, the following process sequence can be cyclically performed to customize the oxidation and removal of tungsten: (a) forming a first tungsten oxide portion on top of the tungsten oxide layer on the substrate field, forming a second tungsten oxide portion on top of the sidewall, and forming a third tungsten oxide portion on top of the dielectric bottom surface; and (b) removing the first, second, and third tungsten oxide portions, wherein the second tungsten portion is completely removed from the sidewall. In embodiments, process sequences (a) and (b) can be performed sufficiently to remove all the first tungsten portions 291 and form Figure 3E The structure shown is cycled in multiple loops, wherein only the third tungsten portion 293 remains on top of the dielectric material of the substrate 200 or is deposited directly on top of the dielectric material. In an embodiment, 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 Figure 3E The structure shown.
[0048] Figure 7 This is a flowchart of a method 700 for selectively depositing a tungsten layer on top of a dielectric surface according to some embodiments of this disclosure. (The following refers to...) Figures 4A to 4DThe described method 700 describes the stages of a processed substrate. The method described herein can be performed in a separate processing chamber, such as a physical vapor deposition (PVD) chamber or an etching chamber that can be constructed independently or provided as part of one or more cluster tools, such as... Figure 6 The integrated tool 600 shown (i.e., cluster tool) or those chambers such as those obtained from Applied Materials, Inc., Santa Clara, CA. Other processing chambers (including those obtained from other manufacturers) may also be adapted to benefit from this disclosure.
[0049] Figures 4A to 4D The illustrations depict the stages of selectively depositing a tungsten layer on top of 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 top of a dielectric surface, comprising: depositing a tungsten layer on top of a substrate field and on top of characteristic sidewalls and a dielectric bottom surface disposed in the substrate via a physical vapor deposition (PVD) process, as shown at process sequence 702, to form a first tungsten portion having a first thickness on top of the substrate field, a second tungsten portion having a second thickness on top of the sidewalls, and a third tungsten portion having a third thickness on top of 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 at process sequence 704, wherein the first tungsten portion and the second tungsten portion are completely removed from the substrate, and wherein the third tungsten portion remains on top of the dielectric bottom surface.
[0050] Figure 4A The diagram illustrates the above text. Figure 2A The substrate 200 of the embodiment described herein. Figure 4B The illustration shows a PVD-deposited tungsten layer 231 on top of the substrate field 225, on top of the sidewall 220, and on top of the dielectric bottom surface 222 of features (such as trenches 210) provided in the substrate 200. This forms a first tungsten portion 291 with a first thickness on top of the substrate field 225, a second tungsten portion 292 with a second thickness on top of the sidewall 220, and a third tungsten portion 293 with a third thickness on top of the dielectric bottom surface 222. In this embodiment, the second thickness is less than the first and third thicknesses. The PVD reaction conditions and thicknesses (such as the first, second, and third thicknesses) may be the same as those described above.
[0051] See Figure 4B and Figure 4CEmbodiments of this disclosure include the removal of 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, the tungsten etchback of the first tungsten portion 291 and the second tungsten portion 292 is achieved by using a tungsten halide plasma (e.g., WF6 plasma) and 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 embodiments, the substrate 200 is disposed within 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 the atomic fluorine is used to etch at least the metallic tungsten of the first tungsten portion 291 and the second tungsten portion 292. In embodiments, the etching rate depends on the WF6 flow rate and plasma conditions. By adjusting the process conditions, a very suitable etching rate in the range of 0.5 Å / s to 3 Å / s can be achieved to control the amount of etchback. In this implementation, since WF6 can be used as both a deposition precursor and an etchant in the chamber, a single-chamber deposition-etch-deposition process can be achieved. A standard PVD chamber with RF or RPS plasma capability can perform both deposition and etch-back, thereby providing improved throughput and chamber redundancy.
[0052] In some embodiments, a tungsten-containing gas is used to etch the first tungsten portion 291 and the second tungsten portion 292 to remove portions of the first tungsten portion 291 and the second tungsten portion 292. The etching process (also known as a back-etching process) removes portions of the first tungsten portion 291 and the second tungsten portion 292 along the sidewall 220. The etching process can also be performed in the same processing chamber as the tungsten deposition process. In embodiments, plasma can be formed by coupling radio frequency (RF) power to a processing gas, such as helium (He), argon (Ar), oxygen (O2), nitrogen (N2), or a combination of the above gases. The plasma can be formed by a remote plasma source (RPS) and delivered to the processing chamber.
[0053] In an embodiment, the temperature of substrate 200 can vary from about 100 degrees Celsius to about 600 degrees Celsius during the etching process (e.g., in the range of about 300 degrees Celsius to 430 degrees Celsius). In an embodiment, etching of the first tungsten portion 291 and the second tungsten portion 292 can be performed, wherein 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 approximately 1 Torr. In an embodiment, a process gas (e.g., argon (Ar)) can be introduced from 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 used 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, such as in the range of about 3 sccm to 100 sccm.
[0054] In an embodiment, after the etch-back process 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 as described herein. Figure 4D The structure shown. For example, in some embodiments, it is provided to be sufficient for soaking. Figure 4C The structure shown removes an amount of tungsten hexafluoride (WF6) from the sidewall 220, removing all tungsten oxide. (As shown...) Figure 4C and Figure 4D As shown, at least a portion of the third tungsten portion 293 remains on top of the dielectric substrate surface 222, and no tungsten remains on top of the substrate field 225 and the sidewall 220. In embodiments, examples of reducing gases may include hydrogen and NH3 gas. In embodiments, hydrogen and NH3 gas may be used alone or in mixtures thereof. In this embodiment, a reducing gas comprising WF6 is used alone.
[0055] Figures 5A to 5EThe illustrations depict the stages of selectively depositing a tungsten layer on top of 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 top of a dielectric surface, comprising: depositing a tungsten layer on top of a substrate field and on top of characteristic sidewalls and a dielectric bottom surface disposed in the substrate via a physical vapor deposition (PVD) process to form a first tungsten portion having a first thickness on top of the substrate field, a second tungsten portion having a second thickness on top of the sidewalls, and a third tungsten portion having a third thickness on top of the dielectric bottom surface, wherein the second thickness is less than the first thickness and the third thickness; forming a first oxidized tungsten portion on top of the substrate field, a second oxidized tungsten portion on top of the sidewalls, and a third oxidized tungsten portion on top of the dielectric bottom surface on the top surface of a tungsten oxide layer; removing the first oxidized tungsten portion, the second oxidized tungsten portion, and the third oxidized tungsten portion, wherein the second tungsten portion is completely removed from the sidewalls; and removing the first tungsten portion from the substrate field.
[0056] Figure 5A The diagram illustrates the above text. Figure 2A The substrate 200 of the embodiment described herein. Figure 5B The illustration shows a PVD-deposited tungsten layer 231 on top of the substrate field 225, on top of the sidewall 220, and on top of the dielectric bottom surface 222 of features (such as trenches 210) provided in the substrate 200. A first tungsten portion 291 with a first thickness is formed on top of the substrate field 225, a second tungsten portion 292 with a second thickness is formed on top of the sidewall 220, and a third tungsten portion 293 with a third thickness is formed on top of the dielectric bottom surface 222. In this embodiment, the second thickness is less than the first and third thicknesses.
[0057] In this embodiment, the PVD chamber is as disclosed in U.S. Patent No. 9,062,372, entitled "Self-Ionized and Capacitively-Coupled Plasma For Sputtering and Resputtering," by Gopalraja et al. and assigned to Applied Materials. In this embodiment, a suitable processing chamber sputterer is configured for sputtering tungsten via self-ionized plasma (SIP).
[0058] In this embodiment, PVD deposition is performed by self-ionizing plasma (SIP) sputtering to deposit tungsten. In this embodiment, a magnetic field generated by an electromagnetic coil confines the plasma generated by capacitive coupling to increase plasma density and thus ionization rate. Long-stroke sputtering is characterized by a relatively high ratio of target-to-substrate distance to substrate diameter. Long-stroke SIP sputtering facilitates deep-hole coating with ionized and neutral deposition material compositions. CCP resputtering can reduce the thickness of the layer covering the bottom of deep holes to reduce contact resistance.
[0059] In implementations, SiP tends to be promoted by low pressures of less than 5 mTorr. Particularly at low pressures, SiP tends to be promoted by magnetrons with relatively small areas, resulting in increased target power density, and by magnetrons with asymmetric magnets, resulting in magnetic fields penetrating further toward the substrate. According to one aspect of this disclosure, plasma conditions for SiP sputtering to deposit target materials are provided.
[0060] In one embodiment, a reactor comprising a DC magnetron type reactor is provided, based on a modification of the EnduraPVD reactor available from Applied Materials, Inc., Santa Clara, CA. In another embodiment, the reactor is capable of self-ionization sputtering (SIP) in a long-stroke mode. The SIP mode can be used in one embodiment where non-uniform coverage is desired, such as coverage primarily against the orifice sidewalls. The SIP mode can also be used to achieve more uniform coverage. In yet another alternative embodiment, the pressure in the chamber can be varied between steps. For example, the pressure can be increased during SIP sputtering.
[0061] To attract ions generated by the plasma, for example, a tungsten target can be negatively biased by a variable DC power supply at a DC power of 1–40 kW. The power supply is negatively biased relative to the chamber shielding target to approximately -400 to -600 VDC to ignite and sustain the plasma. Voltages less than -1000 VDC are generally suitable for use herein. Target power between 1 and 5 kW is typically used to ignite the plasma, while power greater than 10 kW is suitable for the SIP sputtering described herein. For example, a target power of 24 kW can be used to deposit tungsten via SIP sputtering.
[0062] In one implementation, a power supply can apply RF power to the substrate electrodes to bias the substrate and attract deposited material ions during SIP sputtering deposition. During SIP deposition, the substrate and therefore the substrate 200 can remain electrically floating, but a negative DC self-bias can still be formed on the substrate and therefore the substrate 200. Alternatively, the substrate can be negatively biased by the power supply at -30VDC to attract ionized deposited material to the substrate.
[0063] In some embodiments, when argon gas is allowed to enter the PVD processing chamber, a DC voltage difference between the target (such as a tungsten target) and the chamber shield ignites the argon gas into a plasma, attracting positively charged argon ions to the negatively charged target. The ions bombard the target with considerable energy, causing target atoms or clusters of atoms to sputter from the target. Some target particles bombard the substrate 200 and deposit on the substrate 200, thereby forming a PVD deposition layer of tungsten material, such as... Figure 5B As shown. In reactive sputtering of tungsten material, tungsten is deposited to form a first tungsten portion 291 with a first thickness on top of substrate field 225, a second tungsten portion 292 with a second thickness on top of sidewall 220, and a third tungsten portion 293 with a third thickness on top of dielectric bottom surface 222. In some embodiments, the second thickness is less than the first and third thicknesses. In some embodiments, the third thickness is thicker than the first and second thicknesses. 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] See Figure 5C Embodiments of this disclosure include the top surface 251 of a tungsten oxide layer 231 of a first thickness or the top surface of a first tungsten portion 291, the top surface of a second tungsten portion 292 of a second thickness on the top of a sidewall 220, and the top surface of a third tungsten portion 293 to form a first tungsten oxide portion 254 on the top of a substrate field, a second tungsten oxide portion 256 on the top of the sidewall 220, and a third tungsten oxide portion 258 on the top of a dielectric substrate or on a tungsten top deposited on the dielectric substrate. In an embodiment, plasma and oxygen are applied under conditions sufficient to convert the tungsten portions of the first and third portions into tungsten oxide while completely converting the tungsten on the top of the sidewall 220 into tungsten oxide. In an embodiment, the first tungsten portion is converted into tungsten oxide more than the third tungsten portion. In an embodiment, this disclosure includes preselecting or tuning the thickness of the first tungsten oxide portion 254 while limiting the thickness of the third tungsten oxide portion 258 on the top of the dielectric substrate or on a tungsten top deposited on the dielectric substrate.
[0065] In an embodiment, after forming a first oxidized tungsten portion 254 on top of the substrate, a second oxidized tungsten portion 256 on top of the sidewall 220, and a third oxidized tungsten portion 258 on top of the dielectric bottom surface or on a tungsten top deposited on the dielectric bottom, the substrate 200 may be further processed to form such a... Figure 5E The structure shown. For example, in some embodiments, it is provided to be sufficient for soaking. Figure 5CThe structure shown removes an amount of tungsten hexafluoride (WF6) from the sidewall 220, removing all tungsten oxide. (As shown...) Figure 5C and Figure 5D As shown, at least a portion of the third tungsten portion 293 remains on top of the dielectric substrate 222. After further etching, and as... Figure 5E As shown, no tungsten residue remains on the substrate field 225 and the top of the sidewall 220. In embodiments, examples of reducing gases may include hydrogen and NH3 gas. In embodiments, hydrogen and NH3 gas may be used alone or in mixtures thereof. In this embodiment, a reducing gas comprising WF6 is used alone.
[0066] The tungsten-containing layer exhibits its advantages when integrated with conventional filling techniques as described above to form features with excellent film properties. Integration schemes may include physical vapor deposition (PVD) and plasma-enhanced methods for depositing the tungsten layer. Etching chambers are also suitable for use herein. Integration processing systems capable of performing the integration methods disclosed herein include... SL, or The processing systems described above are available from Applied Materials, Inc., located in Santa Clara, CA. In one embodiment, a physical vapor deposition (PVD) and etching chamber may be provided to perform all vapor deposition and etching processes associated with the tungsten layer on top of the dielectric layer.
[0067] See now Figure 6 The methods described herein can be performed in a separate processing chamber, which may be constructed independently or provided as part of one or more cluster tools, such as those described below. Figure 6 The described integration tool 600 (i.e., clustering tool) is configured to perform methods such as method 100 for selectively depositing a tungsten layer on top of a dielectric surface, including: (a) depositing a tungsten layer on top of a substrate field and on top of characteristic sidewalls and a dielectric bottom surface disposed in the substrate via a physical vapor deposition (PVD) process to form a first tungsten portion having a first thickness on top of the substrate field, a second tungsten portion having a second thickness on top of the sidewalls, and a third tungsten portion having a third thickness on top of 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 oxidized tungsten portion on top of the substrate field, a second oxidized tungsten portion on top of the sidewalls, and a third oxidized tungsten portion on top of the dielectric bottom surface; (c) removing the first oxidized tungsten portion, the second oxidized tungsten portion, and the third oxidized tungsten portion, wherein the second tungsten portion is completely removed from the sidewalls; and (d) passivating or completely removing the first tungsten portion from the substrate field.
[0068] In implementations, the clustering tool may be configured to include additional chambers. Non-limiting examples of additional chambers for selective metal deposition include those available from Applied Materials, Inc., Santa Clara, CA. Branded processing chambers. Examples of integrated tools 600 include those available from Applied Materials, Inc., Santa Clara, CA. and Integrated tools. However, the methods described herein can be practiced using other clustered tools with suitable processing chambers coupled thereto or in other suitable processing chambers. For example, in some embodiments, the inventive methods discussed above can be advantageously performed in integrated tools such that there is a limited vacuum interruption or no vacuum interruption during processing.
[0069] In one embodiment, the integration tool 600 may include two load-locking chambers 606A, 606B for transferring a substrate into and out of the integration tool 600. Typically, because the integration tool 600 is under vacuum, the load-locking chambers 606A, 606B can be “evacuated” to introduce the substrate into the integration tool 600. A first robot 410 can transfer the substrate between the load-locking chambers 606A, 606B and a first set of one or more substrate processing chambers 612, 614, 616, 618 (four illustrated) coupled to a first central transfer chamber 650. Each substrate processing chamber 612, 614, 616, 618 may be configured to perform multiple substrate processing operations. In some embodiments, the first set of one or more substrate processing chambers 612, 614, 616, 618 may include any combination of PVD, etching, ALD, CVD, or degassing chambers. For example, in some embodiments, substrate processing chambers 612 and 614 include processing chambers suitable for PVD deposition, which are configured to deposit tungsten on top of the substrate as described above.
[0070] In some embodiments, the first robot 610 may also transfer substrates to or 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 integrated tooling 600. The second robot 630 may transfer substrates between the intermediate transfer chambers 622, 624 and a second set of one or more substrate processing chambers 632, 634, 635, 636, 638 coupled to a second central transfer chamber 655. The substrate processing chambers 632, 634, 635, 636, 638 may be configured to perform various substrate processing operations, including physical vapor deposition (PVD), chemical vapor deposition (CVD), selective metal deposition, etching, orientation, and other substrate processes, as well as the methods 300, 400 described above. For a specific process to be performed by the integration tool 600, any of the substrate processing chambers 612, 614, 616, 618, 632, 634, 635, 636, and 638 may be removed from the integration tool 600 (if the substrate processing chamber is not necessary). In an embodiment, the microprocessor includes a memory, such as a non-transitory computer-readable medium storing instructions that, when executed, cause the integration tool or reaction chamber to perform a method of selectively depositing a tungsten layer on top of a dielectric surface in accordance with this disclosure.
[0071] In some embodiments, this disclosure relates to a non-transitory computer-readable medium having instructions stored thereon that, when executed, cause a reaction chamber to perform a method of selectively depositing a tungsten layer on top of a dielectric surface, comprising: (a) depositing a tungsten layer on top of a substrate field and on top of characteristic sidewalls and a dielectric bottom surface disposed in the substrate via a physical vapor deposition (PVD) process to form a first tungsten portion having a first thickness on top of the substrate field, a second tungsten portion having a second thickness on top of the sidewalls, and a third tungsten portion having a third thickness on top of 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 oxidized tungsten portion on top of the substrate field, a second oxidized tungsten portion on top of the sidewalls, and a third oxidized tungsten portion on top of the dielectric bottom surface; (c) removing the first oxidized tungsten portion, the second oxidized tungsten portion, and the third oxidized tungsten portion, wherein the second tungsten portion is completely removed from the sidewalls; and (d) passivating or completely removing the first tungsten portion from the substrate field.
[0072] In some embodiments, this disclosure relates to a non-transitory computer-readable medium having instructions stored thereon that, when executed, cause a reaction chamber to perform a method of selectively depositing a tungsten layer on top of a dielectric surface, comprising: (a) depositing a tungsten layer on top of a substrate field and on top of characteristic sidewalls and a dielectric bottom surface disposed in the substrate via a physical vapor deposition (PVD) process to form a first tungsten portion having a first thickness on top of the substrate field, a second tungsten portion having a second thickness on top of the sidewalls, and a third tungsten portion having a third thickness on top of 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 wherein the third tungsten portion remains on top of the dielectric bottom surface.
[0073] In some embodiments, this disclosure relates to a method for selectively depositing a tungsten layer on top of a dielectric surface, comprising: (a) depositing a tungsten layer on top of a substrate field and on top of characteristic sidewalls and a dielectric bottom surface disposed in the substrate via a physical vapor deposition (PVD) process to form a first tungsten portion having a first thickness on top of the substrate field, a second tungsten portion having a second thickness on top of the sidewalls, and a third tungsten portion having a third thickness on top of 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 oxidized tungsten portion on top of the substrate field, a second oxidized tungsten portion on top of the sidewalls, and a third oxidized tungsten portion on top of the dielectric bottom surface; (c) removing the first oxidized tungsten portion, the second oxidized tungsten portion, and the third oxidized tungsten portion, wherein the second tungsten portion is completely removed from the sidewalls; and (d) passivating or completely removing the first tungsten portion from the substrate field. In embodiments, (a), (b), (c), and (d) are performed sequentially. In embodiments, (b) and (c) are cyclically repeated in cycles sufficient to remove the first tungsten portion from the substrate field, wherein the third oxidized tungsten portion remains on top of the dielectric substrate surface. In some embodiments, deposition includes forming a first and third thickness greater than the second thickness. In embodiments, oxidation is characterized as conformal or superconformal. In embodiments, oxidation includes contacting the top surface of the tungsten layer with an oxygen plasma. In embodiments, removal includes contacting the first, second, and third oxidized tungsten portions with WF6 under conditions sufficient to remove the second oxidized tungsten portion from the sidewalls. In embodiments, passivation includes 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 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, oxidation further includes providing an oxygen-containing capacitively coupled plasma at a temperature of about 300 to about 400 degrees Celsius.
[0074] In some embodiments, a method for selectively depositing a tungsten layer on top of a dielectric surface includes: (a) depositing a tungsten layer on top of a substrate field and on top of characteristic sidewalls and a dielectric bottom surface disposed in the substrate via a physical vapor deposition (PVD) process to form a first tungsten portion having a first thickness on top of the substrate field, a second tungsten portion having a second thickness on top of the sidewalls, and a third tungsten portion having a third thickness on top of 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, wherein the second tungsten portion is completely removed from the sidewalls; and wherein the third tungsten portion remains on top of the dielectric bottom surface. In some embodiments, deposition includes forming a first thickness and a third thickness greater than the second thickness. In embodiments, removal further includes contacting the substrate with WF6 under conditions sufficient to remove tungsten from the sidewalls.
[0075] In some embodiments, this disclosure relates to a method for selectively depositing a tungsten layer on top of a dielectric surface, comprising: (a) depositing a tungsten layer on top of a substrate field and on top of characteristic sidewalls and a dielectric bottom surface disposed in the substrate via a physical vapor deposition (PVD) process to form a first tungsten portion having a first thickness on top of the substrate field, a second tungsten portion having a second thickness on top of the sidewalls, and a third tungsten portion having a third thickness on top of 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 oxidized tungsten portion on top of the substrate field, a second oxidized tungsten portion on top of the sidewalls, and a third oxidized tungsten portion on top of the dielectric bottom surface; (c) removing the first oxidized tungsten portion, the second oxidized tungsten portion, and the third oxidized tungsten portion, wherein the second tungsten portion is completely removed from the sidewalls; and (d) passivating or completely removing the first tungsten portion 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 includes forming a first thickness and a third thickness 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 to 7 nm. In some embodiments, the second tungsten oxide portion has a thickness equal to or equal to the second thickness and may have a thickness such as about 1 to 3 nm. In some embodiments, the third tungsten oxide portion has a thickness of about 3 to 7 nm, such as about 5, 6, or 7 nm.
[0076] In some embodiments, this disclosure relates to a method for selectively depositing a tungsten layer on top of a dielectric surface, comprising: (a) depositing a tungsten layer on top of a substrate field and on top of characteristic sidewalls and a dielectric bottom surface disposed in the substrate via a physical vapor deposition (PVD) process to form a first tungsten portion having a first thickness on top of the substrate field, a second tungsten portion having a second thickness on top of the sidewalls, and a third tungsten portion having a third thickness on top of 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 first tungsten portion and the second tungsten portion are completely removed from the substrate, and wherein the third tungsten portion remains on top of the dielectric bottom surface. In embodiments, the first thickness is less than the third thickness. In embodiments, the deposition further comprises forming a first thickness less than the third thickness. In embodiments, the deposition further comprises forming a first thickness and a third thickness greater than the second thickness. In embodiments, the first thickness is about 7 to 9 nm. In embodiments, the second thickness is about 1 to 3 nm. In embodiments, the third thickness is about 9 to 11 nm. In one embodiment, 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 this disclosure, other and further embodiments of this disclosure may be designed without departing from the basic scope of this disclosure.
Claims
1. A method for selectively depositing a tungsten layer on top of a dielectric surface, comprising the following steps: (a) A tungsten layer is deposited on a substrate top and on the sidewalls and dielectric bottom surface of a feature disposed in the substrate via physical vapor deposition (PVD) to form a first tungsten portion having a first thickness on the substrate top, 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 substrate, and wherein the third tungsten portion remains on top of the dielectric substrate surface. The first thickness is less than the third thickness.
2. The method of claim 1, wherein during (b), the first tungsten portion is completely removed from the substrate.
3. The method of claim 1, further comprising the following steps: (c) Prior to (b), the top surface of the tungsten layer is oxidized to form a first oxidized tungsten portion on the top of the substrate field, a second oxidized tungsten portion on the top of the sidewall, and a third oxidized tungsten portion on the top of the dielectric bottom surface; Wherein (b) further comprises removing the first oxidized tungsten portion, the second oxidized tungsten portion, and the third oxidized tungsten portion; and (d) Passivate or completely remove the first tungsten portion from the substrate field.
4. The method of claim 3, wherein the step of oxidizing the top surface of the tungsten layer is characterized as conformal or super-conformal.
5. The method of claim 3, 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 oxygen plasma.
6. The method of claim 3, wherein the oxidation step further comprises the step of providing an oxygen-containing capacitively coupled plasma at a temperature of 300°C to 400°C.
7. The method of claim 3, wherein the removal step comprises the step of: 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.
8. The method of claim 3, wherein the first tungsten portion is passivated and wherein the passivation step comprises the step of contacting the first tungsten portion with a remote nitrogen plasma at a temperature of 300 to 400 degrees Celsius, wherein the nitrogen is provided at a flow rate of 0.5 to 5 sccm or less than 5 sccm.
9. The method of claim 3, wherein the passivation step comprises the step of contacting the first tungsten portion with a remote nitrogen plasma at a pressure of 500 mTorr to 1 Torr, wherein the nitrogen is supplied at a flow rate of 0.5 to 5 sccm or less than 5 sccm.
10. The method of any one of claims 3 to 9, wherein (b) and (c) are repeated cyclically in a cycle sufficient to remove the first tungsten portion from the substrate field, and wherein the third oxidized tungsten portion remains on top of the dielectric substrate surface.
11. The method of any one of claims 1 to 9, wherein at least one of the following: 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.
12. The method of claim 10, wherein at least one of the following: 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.
13. A non-transitory computer-readable medium having instructions stored thereon, the instructions, when executed, causing a reaction chamber to perform a method of selectively depositing a tungsten layer on top of a dielectric surface, said method as described in any of the preceding claims.