Method of reducing titanium nitride etching during tungsten film formation

Abstract

Various methods are provided for forming electronic components comprising stacked tungsten films. These methods include forming a tungsten nucleation layer on a barrier layer using an atomic layer deposition (ALD) process comprising a fluorine-free tungsten precursor. Forming this nucleation layer includes controlling process parameters and / or forming a WSi pre-nucleation layer.

Description

[Technical Field]

[0001] The embodiments disclosed in this application belong to the field of electronic component manufacturing, and more particularly to the manufacturing of integrated circuits (ICs). In particular, the embodiments disclosed in this application relate to low-resistivity tungsten films and methods for manufacturing low-resistivity tungsten films. [Previous Technology]

[0002] The rapid growth of mobile devices, the Internet of Things (IoT), and machine learning necessitates superior transistor performance and lower power consumption. This requires continuous advancements in transistor technology to shrink device size and multiply chip density in accordance with Moore's Law. Integrated circuits can be fabricated through processes that create intricately patterned material layers on a substrate surface. Creating patterned materials on a substrate requires controlled methods to deposit the desired material. In patterning and other applications, it is practical to selectively deposit films on one surface relative to different surfaces.

[0003] Tungsten deposition based on WF6 has been used in the fabrication of integrated circuits, and this method requires a fluorine barrier layer and a tungsten nucleation layer with high resistivity. However, these two layers occupy a considerable volume and tend to cause high resistivity, which affects the overall device performance. In conventional fill processes using tungsten deposition, a titanium nitride (TiN) layer is deposited on a dielectric substrate as a barrier layer and a pad layer, followed by the deposition of a bulk tungsten (W) film nucleation layer or seed layer.

[0004] Chemical vapor deposition (CVD) is a deposition process used to deposit layers (including tungsten layers) on a substrate. Atomic layer deposition (ALD), also known as cyclic deposition, uses chemisorption technology to deliver precursor molecules to the substrate surface in multiple sequential cycles. Each cycle exposes the substrate surface to a first precursor, a purge gas, a second precursor, and another purge gas. The first and second precursors react to form a product compound as a film on the substrate surface. This cycle is repeated to form a layer of desired thickness. The deposition of a tungsten film involves forming a titanium nitride or other metal barrier layer between the substrate and the tungsten film, and this barrier layer is etched as part of the tungsten nucleation layer deposition process. It has been found that in processes used to deposit fluorine-free tungsten nucleation layers, the etching of the barrier layer can cause voltage tuning (Vt) offset problems. Therefore, there is a need for improved methods for forming tungsten nucleation layers that reduce the etching of barrier materials such as TiN. [Summary of the Invention]

[0005] Various methods for depositing metal films are described. In one embodiment, a method for forming a tungsten stack on a substrate includes: forming a barrier layer on the surface of the substrate; forming a tungsten nucleation layer on the barrier layer using an atomic layer deposition (ALD) process comprising a fluorine-free tungsten precursor, wherein the ALD process includes process pressure, ALD precursor pulse duration, substrate processing temperature, and tungsten precursor temperature before the precursor is delivered to the ALD processing chamber; controlling the ALD process pressure, the ALD precursor pulse duration, the substrate processing temperature, and the tungsten precursor temperature during the ALD process for forming the tungsten nucleation layer to reduce etching of the barrier layer; and forming a tungsten film directly on the tungsten nucleation layer.

[0006] In another embodiment, a method for forming a tungsten stack on a substrate includes: forming a TiN barrier layer on the surface of the substrate; forming a WSi pre-nucleation layer on the TiN barrier layer by passing through multiple alternating pulses of flowing fluorine-free tungsten precursor and silane; forming a tungsten nucleation layer on the barrier layer using an atomic layer deposition (ALD) process including a fluorine-free tungsten precursor, wherein the ALD process includes process pressure, precursor pulse duration, substrate processing temperature, and tungsten precursor temperature before the precursor is delivered to the ALD processing chamber; and forming a tungsten film directly on the tungsten nucleation layer.

[0007] In another embodiment, a method for forming a tungsten stack on a substrate includes: forming a TiN barrier layer on the surface of the substrate; forming a tungsten nucleation layer on the TiN barrier layer using an atomic layer deposition (ALD) process comprising a fluorine-free tungsten precursor, wherein the atomic layer deposition process includes process pressure, ALD precursor pulse duration, substrate processing temperature, and tungsten precursor temperature before the precursor is delivered to the ALD processing chamber; flowing TiCl4 during the formation of the tungsten nucleation layer; and forming a tungsten film directly on the tungsten nucleation layer.

Implementation Method

[0014] Before describing several exemplary embodiments of the disclosure herein, it should be understood that the disclosure is not limited to the details of the construction or process steps set forth in the following description. The disclosure may have other embodiments and may be implemented or performed in various ways.

[0015] As used herein, "substrate" means any substrate on which a film treatment is performed during a manufacturing process, or a material surface formed on a substrate. For example, substrate surfaces on which treatments can be performed include materials such as silicon, silicon oxide, strained silicon, silicon-on-insulator (SOI), carbon-doped silicon oxide, amorphous silicon, doped silicon, germanium, gallium arsenide, glass, sapphire, and any other materials such as metals, metal nitrides, metal alloys, and other conductive materials, depending on the application. Substrates include, but are not limited to, semiconductor wafers. Substrates may be exposed to pretreatment processes such as polishing, etching, reduction, oxidation, hydroxylation, annealing, UV curing, electron beam curing, and / or baking of the substrate surface. In addition to performing film treatments directly on the surface of the substrate itself, any film treatment steps disclosed herein may also be performed on an underlayer formed on a substrate as disclosed in more detail below, and the term "substrate surface" is intended to include such an underlayer as indicated by the context. Therefore, for example, when a film / layer or part of a film / layer has been deposited on the substrate surface, the exposed surface of the newly deposited film / layer becomes the substrate surface.

[0016] As used in this specification and the appended claims, the terms "precursor", "reactant", "reacting gas", etc., are used interchangeably to refer to any gaseous substance capable of reacting with the surface of the substrate.

[0017] As used herein, the term "liner" refers to a layer that is conformally formed along at least a portion of the sidewalls and / or lower surface of an opening, such that a majority portion of the opening prior to the deposition of the layer remains unfilled after the deposition of the layer. In some embodiments, the liner may be formed integrally along the sidewalls and lower surface of the opening. The liner may also be formed on a flat surface of a flat substrate.

[0018] Advantageously, a fluorine-free tungsten (FFW) nucleation layer deposition process has been discovered, which provides better nucleation for bulk tungsten growth and also prevents fluorine diffusion. Furthermore, in certain embodiments, a film with low resistivity is produced. The processes described herein include CVD and ALD processes. In one or more embodiments, FFW growth is based on an etching mechanism of an underlying metal layer such as TiN. In a particular embodiment, during etching that occurs during the W nucleation layer deposition process, tungsten (W) atoms adsorb onto nitrogen (N) atoms, and Cl atoms adsorb onto titanium (Ti) atoms, forming an active layer of titanium nitride (TiN) etched. The presence of hydrogen (H2) during the ALD cycle helps to dissociate WClx by breaking W-Cl bonds and further aids in tungsten film growth.

[0019] According to one or more embodiments, the method described herein provides an efficient way to reduce barrier layer etch and loss (e.g., TiN barrier layer etch and loss) during tungsten deposition processes. In specific embodiments, the method described herein provides an efficient way to reduce barrier layer etch and loss (e.g., TiN etch and loss during ALD FFW processes). According to one or more embodiments, barrier layer etch loss is reduced through process condition control and pre-deposition treatment. According to one or more embodiments, reduced TiN etching is achieved through lower process pressure, lower substrate support temperature, lower precursor container (e.g., ampoule) temperature, and shorter reactant pulse time.

[0020] According to one or more embodiments of the process described herein, a WSi pre-nucleation deposition method is used to form a protective quasi-layer on the surface of a barrier layer (e.g., a TiN barrier layer). In certain embodiments, the pre-nucleation deposition method utilizes an ALD process. One or more advantages are achieved according to the embodiments described herein. In some embodiments, a method is provided that can be performed in a single chamber to achieve a reduction in barrier layer etching. In some embodiments, the total throughput time of the process remains unchanged or is improved compared to existing processes. In one or more embodiments of the method described herein, the method avoids the introduction of any impurities into the tungsten film.

[0021] According to one or more embodiments, TiN etching loss is reduced by utilizing the pressure of a substrate processing chamber (e.g., an ALD chamber) ranging from 15 to 30 tones. In more specific embodiments, the pressure of the substrate processing chamber (such as an ALD chamber) during the deposition of the tungsten nucleation layer is in the following ranges: from 20 to 30 tones, from 21 to 30 tones, from 22 to 29 tones, from 23 to 28 tones, from 24 to 26 tones, from 25 to 30 tones, from 26 to 29 tones, from 27 to 28 tones, from 27 to 30 tones, or from 28 to 30 tones. Reducing the processing chamber pressure reduces barrier layer etching, particularly TiN barrier layer etching during the process of forming the tungsten nucleation layer.

[0022] In one or more embodiments, reducing the temperature of the substrate support (also referred to as the pedestal) during the deposition of the tungsten nucleation layer also reduces barrier layer etching, particularly TiN barrier layer etching during the process. In specific embodiments, the substrate support is maintained in a temperature range of 400°C to 475°C, 410°C to 470°C, 420°C to 465°C, or 430°C to 460°C, which reduces barrier layer etching, particularly TiN barrier layer etching during the deposition of the tungsten nucleation layer. By heating the substrate support, such as the pedestal, in a substrate processing chamber such as a CVD chamber or an ALD chamber, the substrate temperature can be maintained within the range provided herein. Resistance heating or other heating methods of the substrate support can be utilized. In specific embodiments, operating the substrate processing chamber within the pressure range described herein and maintaining the substrate support within the temperature range provided herein during the process reduces barrier layer etching, particularly TiN barrier layer etching during the process of forming the tungsten nucleation layer.

[0023] In one or more embodiments, the precursor container (e.g., an ampoule) for the tungsten precursor is maintained within a temperature range during tungsten nucleation layer deposition to reduce barrier layer etch. Specifically, maintaining the precursor container within temperature ranges of 100°C to 130°C, 105°C to 125°C, or 109°C to 119°C reduces TiN barrier layer etch during tungsten nucleation layer deposition. In certain embodiments, maintaining the precursor container temperature within the temperature range described herein, operating the substrate processing chamber within the pressure range described herein, and maintaining the substrate support within the temperature range provided herein during processing reduces barrier layer etch, particularly TiN barrier layer etch during the tungsten nucleation layer formation process. The temperature of the precursor container (e.g., the ampoule) can be maintained by placing the precursor container in an oven or resistance heating mantle. In one or more embodiments, during the formation of the tungsten layer's ALD, the duration of the tungsten precursor pulse in the chamber is maintained within the following ranges: from 0.2 seconds to 2.0 seconds, from 0.3 seconds to 1.8 seconds, from 0.4 seconds to 1.6 seconds, or from 0.5 seconds to 1.5 seconds. Maintaining the pulse duration within these ranges reduces barrier layer etching, particularly TiN barrier layer etching during the process of forming the tungsten nucleation layer. In a particular embodiment, maintaining the tungsten precursor pulse duration within the ranges described herein, maintaining the precursor container temperature within the temperature ranges described herein, operating the substrate processing chamber within the pressure ranges described herein, and maintaining the substrate support within the temperature ranges provided herein during processing further reduces barrier layer etching, particularly TiN barrier layer etching during the process of forming the tungsten nucleation layer.

[0024] In addition to the process adjustments of the parameters discussed above, barrier layer etch, particularly TiN barrier layer etch, can be reduced by forming a WSi pre-nucleation layer on the TiN barrier layer before depositing the tungsten nucleation layer. In one or more embodiments, the WSi layer is grown using an ALD process with alternating pulses of tungsten precursors such as tungsten chloride or tungsten bromide and methane (SiH4). Experimental results show that after ten (10) ALD cycles of WF6 and methane, TiN etch can be reduced by up to 30% after tungsten growth. The embodiments described herein provide process conditions for minimizing TiN loss during tungsten nucleation layer deposition. In some embodiments, the flow of up to 10 vol% TiCl4 during the formation of the tungsten nucleation layer, for example, 0.5-1 vol%, 1-2 vol%, 1-3 vol%, 1-4 vol%, 1-5 vol%, 1-6 vol%, 1-7 vol%, 1-8 vol%, 1-9 vol%, or 1-10 vol% TiCl4 reduces the etching of the TiN barrier layer.

[0025] Referring to Figures 1 through 4, an apparatus and method for depositing metal films are described. In one embodiment, referring to Figures 1 and 4, method 200 includes forming a tungsten stack 10 on a substrate 12. The method includes: at 202, forming a barrier layer 14, such as a titanium nitride (TiN) barrier layer 14, on a surface of the substrate 12. Method 200 further includes: at 204, optionally forming a prenucleation layer 15 on the barrier layer, and at 206, forming a tungsten nucleation layer 16 on the prenucleation layer (when present) or on the barrier layer 14 (when the prenucleation layer 15 is absent). Optionally, at 206, according to some embodiments, TiCl4 may flow during the formation of the nucleation layer 16 as further described herein. In one or more embodiments, at 208, adjusting the ALD process pressure, precursor pulse duration, precursor temperature, and / or substrate temperature. Method 200 of one or more embodiments includes: at 210, forming a tungsten film 108 directly on the tungsten nucleation layer 107 using a chemical vapor deposition process or an atomic layer deposition process.

[0026] In some embodiments, the substrate surface includes a feature. In some embodiments, the feature is selected from trenches, vias, or peaks. In a particular embodiment, the feature includes a trench as shown in FIG2.

[0027] In some embodiments, the width W of the trench is greater than or equal to 5 nm and less than or equal to 65 nm, greater than or equal to 5 nm and less than or equal to 55 nm, greater than or equal to 5 nm and less than or equal to 45 nm, greater than or equal to 5 nm and less than or equal to 35 nm, greater than or equal to 5 nm and less than or equal to 32 nm, greater than or equal to 5 nm and less than or equal to 25 nm, or greater than or equal to 5 nm and less than or equal to 22 nm.

[0028] For illustrative purposes, the figures show a substrate with a single feature; however, those skilled in the art will understand that more than one feature is possible. The shape of the feature can be any suitable shape, including but not limited to: peaks, trenches, and cylindrical mesoscopic windows. In a particular embodiment, the feature is a trench. In other particular embodiments, the feature is a mesoscopic window. As used herein, the term "feature" refers to any intentionally formed surface irregularity. Suitable examples of features include, but are not limited to: trenches having a top, two sidewalls, and a bottom; peaks having a top and two sidewalls extending upward from the surface; and mesoscopic windows having sidewalls extending downward from the surface and an open bottom. Features can have any suitable aspect ratio (the ratio of the height H of the feature to its depth to its width). In some embodiments, the aspect ratio is greater than or equal to about 5:1, 10:1, 15:1, 20:1, 25:1, 30:1, 35:1, or 40:1. In one or more embodiments, the aspect ratio is greater than 10:1.

[0029] Referring to Figures 2 and 3, one or more embodiments relate to a method of forming a semiconductor element 100. A substrate 102 is provided with a feature 104, shown as being filled with a tungsten film 108. The shown feature 104 is in the form of a trench, as described above, having a width W and a depth or height H.

[0030] In one or more embodiments, the tungsten film 108 is a CVD-deposited tungsten film. In one embodiment, the tungsten film is a gap-fill layer. As shown in FIG2, in one embodiment, the tungsten film 108 is deposited on a tungsten nucleation layer 107, which is located on the top portion 114 of feature 104, the sidewalls 116 of feature 104, and the top portion 118 of dielectric layer 110. The tungsten nucleation layer 107 is formed on a feature on a barrier layer 106, which in some embodiments is a TiN barrier layer 106.

[0031] In one or more embodiments, the tungsten film 108 is a seed interstitial layer. In one embodiment, the seed interstitial layer is a selectively grown seed film. As shown in FIG2, in one embodiment, the tungsten film 108 is deposited on a tungsten nucleation layer 107, which is located on the top portion 114 of feature 104, the sidewall 116 of feature 104, and the top portion 118 of dielectric layer 110.

[0032] As shown in FIG3, in another embodiment, a tungsten film 108 is deposited on a tungsten nucleation layer 107 on the top portion 114 of feature 104, the sidewall 116 of feature 104, and the top surface 120 of substrate 102. The tungsten nucleation layer 107 is formed on a barrier layer 106, which in some embodiments is a TiN barrier layer 106. In one or more embodiments, the tungsten film 108 is a tungsten layer. In one or more embodiments, the tungsten layer is a tungsten interstitial layer.

[0033] In one or more embodiments, a dielectric layer 110 is formed on a substrate 102. The dielectric layer can be any suitable dielectric material, including but not limited to nitrides, oxides, or carbides of titanium or silicon. The dielectric layer 110 can be formed conformally or non-conformally on the substrate 102.

[0034] In one embodiment, dielectric layer 110 comprises a dielectric material with a k-value less than 5. In one embodiment, dielectric layer 110 comprises a dielectric material with a k-value less than 2. In at least some embodiments, dielectric layer 110 comprises oxide, carbon-doped oxide, porous silica, carbide, carbon oxide, nitride, oxynitride, carbon nitride, polymer, phosphosilate glass, fluorosilate (SiOF) glass, organosilicon glass (SiOCH), or any combination thereof. In at least some embodiments, dielectric layer 110 may comprise polyimide, epoxy resin, photodefined material (such as benzocyclobutene (BCB) and WPR series materials), or spin-coated glass.

[0035] In one embodiment, the thickness of the dielectric layer 110 is approximately in the range of about 10 nanometers (nm) to about 2 micrometers (μm). In one embodiment, the dielectric layer 110 is deposited using one of the following deposition techniques, such as, but not limited to: chemical vapor deposition ("CVD"), physical vapor deposition ("PVD"), molecular beam epitaxy ("MBE"), metal-organic chemical vapor deposition ("MOCVD"), atomic layer deposition ("ALD"), spin coating, or other insulating deposition techniques known to those skilled in the art in the manufacture of microelectronic components.

[0036] One or more embodiments use fluorine-free metal precursors to increase selectivity and deposition rate to form a nucleation layer. Some embodiments also incorporate a reducing agent in the first ALD step to increase selectivity relative to the dielectric and increase the deposition rate while also providing comparable film performance (e.g., step coverage, gap filling). Some embodiments provide highly selective fluorine-free tungsten deposition with a high-throughput ALD process.

[0037] Some embodiments of the disclosure in this case provide an atomic layer deposition method using a reducing agent in the first ALD step. Not bound by any particular operational theory, it is believed that incorporating a reducing agent enables the thermal decomposition of the precursor into different derivatives of the precursor, and results in a significantly greater reduction of the precursor in the main reduction ALD step.

[0038] One or more embodiments of the present invention incorporate different gases (e.g., H2, SiH4, Si2H6, Si4H10, NH3) into the dosing of a metal (e.g., tungsten (W)) precursor. In some embodiments, the incorporation of the reducing agent improves the selectivity of metal deposition relative to the dielectric and accelerates the rate of metal reduction.

[0039] In some embodiments, the ALD replaces and / or reduces the conventional high resistivity nucleation layer (e.g., SiH4 or B2H6 ALD W 20-30 Å) and thick fluorine barrier (e.g., TiN 30-50 Å). In some embodiments, the FFW has low resistivity, excellent step coverage, superior fluorine barrier properties, and can be integrated with conventional WF6-based bulk W filling. Some embodiments improve yield while maintaining acceptable film performance or other parameters (e.g., non-uniformity, step coverage, particle size).

[0040] One or more embodiments of the disclosure herein relate to a method for producing FFW films with high deposition rates. A small amount of a reducing agent (such as H2, SiH4, Si2H6, Si4H12, NH3) is co-currently added to the W precursor ALD dosing step. In some embodiments, FFW growth through the ALD and the co-current of hydrogen (H2) occurs at a suitable temperature (e.g., ranging from 400°C to 550°C, or from 460°C to 475°C).

[0041] The tungsten precursors used for growing FFW include, but are not limited to, tungsten chloride and hydrogen (as a reducing agent). In one or more embodiments, the ALD process includes: exposure to a W precursor flux with a co-flow of H2 at 50-500 sccm, W precursor rinsing, H2 fluxing, and H2 rinsing. In some embodiments, argon (Ar) or other suitable inert gas is used for the precursor carrier and rinsing.

[0042] In one or more embodiments, the fluorine-free tungsten precursor comprises or is substantially composed of tungsten halide. In some embodiments, the tungsten halide comprises one or more of tungsten pentachloride (WCl5) or tungsten hexachloride (WCl6). In some embodiments, the fluorine-free tungsten precursor comprises a tungsten halide precursor, such as WOCl4 or WO2Cl2. In other embodiments, the first process conditions comprise a tungsten precursor selected from the group consisting of fluorine-free or chlorine-free tungsten halide precursors, such as tungsten pentabromide (WBr5) or tungsten hexabromide (WBr6).

[0043] The method for forming a tungsten nucleation layer may further include: flowing a first reducing agent reactive to the tungsten precursor. The first reducing agent (also referred to as a first reducing agent) includes: a reactive gas, such as a hydrogen-containing gas, for example hydrogen (H2) or ammonia (NH3) or hydrazine (N2H4); and a carrier gas, such as argon (Ar), helium (He) or nitrogen (N2). In some embodiments, the carrier gas is an inert gas. In some embodiments, the first gas consists of a metallic tungsten precursor gas, a reactive gas, and a carrier gas, or is substantially composed of the gases described above. In some embodiments, the first gas consists of a chlorine-free, fluorine-free tungsten halide precursor, a hydrogen-containing gas, and an inert gas, or is substantially composed of the gases described above. In some embodiments, the method of claim 1, wherein the first reducing agent includes one or more of the following: hydrogen (H2), methane (SiH4), ethane (Si2H6), propane (Si3H8), butane (Si4H10), or ammonia (NH3).

[0044] In some embodiments, the tungsten precursor flows into the processing area of ​​the processing chamber in a carrier gas. For solid or liquid precursors, in some embodiments, the precursor is held in an ampoule, and the carrier gas flows through the ampoule carrying the precursor. In some embodiments, the carrier gas comprises an inert gas. In some embodiments, the carrier gas comprises one or more of, or is substantially composed of, one or more of, the following gases: helium, neon, argon, nitrogen, krypton, or xenon. As used herein, the flow rate of the metal precursor is the flow rate of the carrier gas comprising the metal precursor.

[0045] According to some embodiments, the total flow rate into the processing area of ​​the processing chamber is a combined flow rate of the metal precursor and the first reducing agent. In some embodiments, a make-up gas flows into the processing area, and the metal precursor and the first reducing agent are added to the make-up gas flow. In some embodiments, the flow rate of the make-up gas flow is much greater than the flow rate of either the metal precursor or the first reducing agent. In some embodiments, the flow rate of the make-up gas flow is greater than 10 times the higher of the precursor flow or the first reducing agent flow.

[0046] In some embodiments, the flow rates of the tungsten precursor and the first reducing agent are configured to provide a tungsten-containing film that is substantially free of tungsten metal. In some embodiments, the first reducing agent has a flow rate in the range of 50 to 500 sccm. Those skilled in the art will understand that the flow rate of the supplementary gas does not change the ratio of the tungsten precursor to the first reducing agent. The supplementary gas flow can change the total concentration of the tungsten precursor and / or the first reducing agent.

[0047] In some embodiments, the flow rate of the first reducing agent is in the range of 5% to 70% of the flow rate of the fluorine-free tungsten precursor. In some embodiments, the flow rate ratio of the fluorine-free tungsten precursor to the first reducing agent is in the range of 10:1 to 1:2.5. The flow of the tungsten precursor and the first reducing agent causes the formation of a first tungsten monolayer of the tungsten nucleation layer.

[0048] In some embodiments, the ALD process for forming the tungsten nucleation layer includes a rinsing process as part of the ALD process. The rinsing process can be any suitable rinsing process that removes unreacted metal precursors or a first reducing agent from the processing area of ​​the processing chamber. In some embodiments, the rinsing process includes flowing an inert gas that is the same as the carrier gas used as the metal precursor.

[0049] In some embodiments, the ALD process includes exposing a first monolayer of the tungsten nucleation layer to a second reducing agent stream. In some embodiments, the second reducing agent is the same species as the first reducing agent. In some embodiments, the second reducing agent is a different species from the first reducing agent. The concentration of the second reducing agent can be the same as or different from the concentration of the first reducing agent. In some embodiments, the second reducing agent includes one or more of the following: hydrogen (H2), methane (SiH4), ethylene (Si2H6), propane (Si3H8), butane (Si4H10), or ammonia (NH3).

[0050] A second rinsing process can be utilized, and this second rinsing process can be any suitable rinsing process that removes unreacted metal precursors or the first reducing agent from the processing area of ​​the processing chamber. In some embodiments, the rinsing process includes flowing an inert gas that is the same as the carrier gas used as the metal precursor. In some embodiments, the inert gas used as the carrier gas for the metal precursor, the carrier / dilution gas (if any) for the reducing agent, the replenishment gas, and the rinsing gas contain the same species.

[0051] Although the disclosure herein has been described with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the disclosure. It will be apparent to those skilled in the art that various modifications and variations can be made to the methods and apparatus disclosed herein without departing from the spirit and scope of the disclosure. Therefore, the disclosure is intended to include modifications and variations within the scope of the appended claims and their equivalents. [Simplified Explanation of the Diagram]

[0008] To gain a more detailed understanding of the features of this disclosure, a more specific description of the disclosure briefly summarized above can be obtained by referring to the embodiments (some of which are illustrated in the accompanying drawings). However, it should be noted that the accompanying drawings illustrate only typical embodiments of the disclosure and should not be considered as limiting its scope, as other equivalent embodiments are permissible. The embodiments described herein are illustrated in the accompanying drawings by way of example rather than limitation, wherein like element symbols indicate similar elements.

[0009] Figure 1 shows a schematic cross-sectional view of a semiconductor device according to one or more embodiments disclosed in this case;

[0010] Figure 2 shows a schematic cross-sectional view of a semiconductor element according to one or more embodiments disclosed in this case;

[0011] Figure 3 shows a schematic cross-sectional view of a semiconductor device according to one or more embodiments disclosed in this case; and

[0012] Figure 4 shows a flowchart of a method according to an embodiment.

[0013] In the accompanying drawings, similar parts and / or features may have the same element symbol. Furthermore, various parts of the same type can be distinguished by adding a dash after the element symbol and a second symbol to differentiate similar parts. If only the first element symbol is used in the specification, the description can be applied to any similar parts having the same first element symbol, regardless of what the second element symbol is. [Biomaterial Storage]

[0053] Domestic storage information (please note in order of storage institution, date, and number): None. International storage information (please note in order of storage country, institution, date, and number): None.

Claims

1. A method for forming a tungsten stack on a substrate, the method comprising: A barrier layer comprising TiN is formed on one surface of the substrate; a WSi prenucleation layer is formed on the barrier layer using an ALD process comprising ten atomic layer deposition (ALD) cycles, wherein the ALD cycle consists of multiple alternating pulses of a fluorine-free tungsten precursor and a silane; a tungsten nucleation layer is formed on the WSi prenucleation layer using an atomic layer deposition (ALD) process comprising a fluorine-free tungsten precursor, wherein the atomic layer deposition process comprises a process pressure, an ALD precursor pulse duration, a substrate processing temperature, and a fluorine-free tungsten precursor temperature before delivery of the precursor to an ALD processing chamber. During the ALD process for forming the tungsten nucleation layer, the ALD process pressure, the ALD precursor pulse duration, the substrate processing temperature, and the fluorine-free tungsten precursor temperature are controlled to reduce the etching of the barrier layer, wherein the WSi pre-nucleation layer formed by ten ALD cycles reduces the etching of the barrier layer during the formation of the nucleation layer; and a tungsten film is formed directly on the tungsten nucleation layer. The method further includes flowing TiCl4 in the range of 0.5 vol% to 10 vol% during the formation of the tungsten nucleation layer to further reduce the etching of the barrier layer.

2. A method for forming a tungsten stack on a substrate, the method comprising: A barrier layer comprising TiN is formed on one surface of the substrate; a WSi prenucleation layer is formed on the barrier layer using an ALD process comprising ten atomic layer deposition (ALD) cycles, wherein the ALD cycle consists of multiple alternating pulses of a fluorine-free tungsten precursor and a silane; a tungsten nucleation layer is formed on the WSi prenucleation layer using an atomic layer deposition (ALD) process comprising a fluorine-free tungsten precursor, wherein the atomic layer deposition process comprises a process pressure, an ALD precursor pulse duration, a substrate processing temperature, and a fluorine-free tungsten precursor temperature before delivery of the precursor to an ALD processing chamber; During the ALD process for forming the tungsten nucleation layer, the ALD process pressure, the ALD precursor pulse duration, the substrate processing temperature, and the fluorine-free tungsten precursor temperature are controlled to reduce the etching of the barrier layer, wherein the WSi pre-nucleation layer formed by ten ALD cycles reduces the etching of the barrier layer during the formation of the nucleation layer; and a tungsten film is formed directly on the tungsten nucleation layer, wherein tungsten atoms are adsorbed on nitrogen atoms and chlorine atoms are adsorbed on titanium atoms, thereby forming an active layer for titanium nitride etching.

3. The method as described in claim 2, further comprising: Hydrogen gas flows during the ALD process, and WClx is dissociated from the barrier layer by breaking the W-Cl bonds.

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