Methods for depositing a tungsten-containing layer

Abstract

The present disclosure provides substrate processing systems and methods thereof. The substrate processing system includes a processing chamber defining a processing volume. A precursor delivery system fluidly coupled to the processing chamber. The substrate processing system includes a controller having instructions stored thereon for performing a method of processing a plurality of substrates when executed by one or more processors. The method includes cleaning the processing chamber. The processing chamber is seasoned. The substrate is received into the processing volume of the processing chamber fluidly coupled to the precursor delivery system. A pre-treatment process is performed on the substrate within the processing chamber. A tungsten-containing layer is deposited onto the substrate.

Description

METHODS FOR DEPOSITING A TUNGSTEN-CONTAINING LAYERBACKGROUNDField

[0001] Embodiments of the present disclosure generally relate to deposition processes and chambers. More specifically, embodiments described herein provide for methods of producing tungsten-containing films.Description of the Related Art

[0002] Integrated circuits are made possible by processes which produce intricately patterned material layers on substrate surfaces. Producing patterned material on a substrate utilizes controlled methods for forming and removing material. Material characteristics may affect how the device operates, and may also affect how the materials are removed relative to one another. One such material that is deposited and removed includes a hardmask. Conventionally, a hardmask is used to pattern trenches and holes into a substrate, in which conventional hardmasks include amorphous silica films and / or boron-doped silica films. Unfortunately, amorphous silica films and / or boron-doped silica films have limited etch selectivity, causing non-uniformities in the trenches after an etching process is performed.

[0003] Attempts to increase etch selectivity have focused on the deposition of tungsten-containing layers as hardmasks, e.g., tungsten silicide (WSi) and / or tungsten silicide nitride (WSiN) using physical vapor deposition (PVD) and / or atomic layer deposition (ALD). Unfortunately, when depositing thick films, e.g., 100 nm to about 500 nm, PVD processes can result in high particle generation, thereby causing contamination, non-uniformities, and requiring cleaning and / or maintenance after a certain number of depositions. Additionally, ALD processes are impractical to deposit thick films, e.g., 100 nm to about 500 nm, due to the number of cycles required.

[0004] Accordingly, there is a need in the art for improved methods of forming thin films on substrates.SUMMARY

[0005] In an embodiment, the present disclosure provides substrate processing systems. The substrate processing system includes a processing chamber defining a processing volume. A precursor delivery system fluidly coupled to the processing chamber. The substrate processing system includes a controller having instructions stored thereon for performing a method of processing a plurality of substrates when executed by one or more processors. The method includes cleaning the processing chamber. The processing chamber is seasoned. The substrate is received into the processing volume of the processing chamber fluidly coupled to the precursor delivery system. A pre-treatment process is performed on the substrate within the processing chamber. A tungsten-containing layer is deposited onto the substrate.

[0006] In another embodiment, the present disclosure provides precursory delivery systems. The precursor delivery system includes at least one radical generator. A controller having instructions is stored thereon for performing a method of processing a plurality of substrates when executed by one or more processors. The method includes cleaning the processing chamber. The processing chamber is seasoned. The substrate is received into the processing volume of the processing chamber fluidly coupled to the precursor delivery system. A pre-treatment process is performed on the substrate within the processing chamber. A tungsten-containing layer is deposited onto the substrate.

[0007] In another embodiment, the present disclosure provides methods for forming a tungsten-containing layer on a substrate. The methods include cleaning a processing chamber. The processing chamber is seasoned. The substrate is received into the processing volume of the processing chamber fluidly coupled to the precursor delivery system. A pre-treatment process is performed on the substrate within the processing chamber. A tungsten-containing layer is deposited onto the substrate.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appendeddrawings illustrate only exemplary embodiments of the disclosure and are therefore not to be considered limiting of scope, as the disclosure may admit to other equally effective embodiments.

[0009] Figure 1 is a schematic side view of a processing system that may be used to implement the methods set forth herein, according to embodiments of the present disclosure.

[0010] Figure 2 is a flow diagram of a method of processing a substrate in a processing system, according to embodiments of the present disclosure.

[0011] Figure 3 is a graphical representation of a tungsten-containing layer deposited over a substrate, according to embodiments of the present disclosure.

[0012] Figure 4 is a schematic cross-sectional view of a process chamber, according to embodiments of the present disclosure.

[0013] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.DETAILED DESCRIPTION

[0014] Embodiments herein are generally directed electronic device manufacturing and, more particularly, to systems and methods for depositing tungsten-containing layers in a semiconductor device manufacturing scheme. The methods described herein can provide a tungsten-containing layer, deposited using CVD and / or PECVD, having a thickness of about 10 nm to about 500 nm with reduced non-uniform ities compared to conventional deposition processes, e.g., PVD processes and / or ALD processes. The tungsten-containing layers can include a grain size of less than 15 A, increasing the uniformity of the tungsten-containing layer compared to conventional PVD and / or ALD processes. Additionally, the tungsten-containing layer can include enhanced adhesion due to the absence of fluorinated tungsten precursors, thereby reducing etching and / or chemical reactions with the substrate surface. The tungsten-containing layer can be controlled to provide wider ranges of compositions of WxSiyNz films, where x is a valuefrom 1 to 100, y is a value from 1 to 100, and z is a value from 0 to 100, compared to conventional deposition processes, e.g., PVD processes and / or ALD processes. A reduction in the cleaning and / or maintenance can be achieved due to the use of a remote plasma source to clean the deposition chamber. Moreover, a reduction in the number of particles and / or contamination occurs due to the remote plasma source with methods described herein compared to PVD processes. A reduction in the number of particles can increase device yield. The methods described herein can provide improved grain size, e.g., below 1 % to 2%, compared to conventional PVD and / or ALD processes, where improved grain size can improve critical dimension uniformity after etching. Moreover, a reduction in manufacturing costs occurs when producing devices uses the methods described herein.

[0015] Figure 1 illustrates a substrate processing system 100. The substrate processing system 100 may be a chemical vapor deposition (CVD) processing chamber and / or a plasma enhanced chemical vapor deposition (PECVD), as described below in reference to FIG. 4. The substrate processing system 100 includes a processing chamber 102, a precursor delivery system 104 fluidly coupled to the processing chamber 102, and a system controller 108. The processing chamber 102 includes a chamber lid assembly 110, one or more sidewalls 112, and a chamber base 114, which collectively define a processing volume 115. The processing volume 115 is fluidly coupled to an exhaust 117, such as one or more vacuum pumps, used to maintain the processing volume 115 at sub- atmospheric conditions and to evacuate processing precursors and processing byproducts therefrom.

[0016] The chamber lid assembly 110 includes a lid plate 116 and a showerhead 118 coupled to the lid plate 116 to define a distribution volume 119. The showerhead 118 faces a substrate support assembly 120 disposed in the processing volume 115. The substrate support assembly 120 is configured to move a substrate support 122 between a raised substrate processing position (as shown) and a lowered substrate transfer position (not shown). When the substrate support assembly 120 is in the raised substrate processing position, the showerhead 118 and the substrate support 122 define a processing region 121.

[0017] The precursor delivery system 104 is fluidly coupled to the processing chamber 102 through the inlet 123 that is disposed through the lid plate 116, one or more sidewalls 112, or both. Processing or cleaning precursors delivered by the precursor delivery system 104 may flow through the inlet 123 and a baffle 124 into the distribution volume 119 and are distributed into the processing region 121 through a plurality of openings 132 in the showerhead 118. The chamber lid assembly 110 further includes a diffusion plate 125, e.g., a perforated diffusion plate, disposed between the inlet 123 and the showerhead 118. The precursors flowed into the distribution volume 119 are first diffused by the diffusion plate 125 to provide a more uniform or desired distribution of precursor flow into the processing region 121. Processing precursors and processing by-products are evacuated from the processing region 121 through exhaust 117 in the one or more sidewalls 112.

[0018] A purge gas source 137 in fluid communication with the processing volume 115 is used to flow a chemically inert purge gas, such as argon (Ar), Helium (He), and / or Krypton (Kr), into a region disposed beneath the substrate support 122, e.g., through the opening in the chamber base 114 surrounding a support shaft 162 on which the substrate support 122 is disposed. The purge gas may be used to create a region of positive pressure below the substrate support 122 when compared to the pressure in the processing region 121 during substrate processing. Typically, purge gas introduced through the chamber base 114 flows up and around the edges of the substrate support 122 to be evacuated from the processing volume 115 through openings in the one or more sidewalls 112.

[0019] The substrate support assembly 120 includes a support shaft 162 that may be surrounded by a bellows 165. In some embodiments, the support shaft 162 may be moveable. The substrate support assembly 120 includes a lift pin assembly 166 comprising a plurality of lift pins 167 coupled to a lift pin hoop 168. The plurality of lift pins 167 are movably disposed in openings formed through the substrate support 122. When the substrate support 122 is disposed in a lowered substrate transfer position (not shown), the plurality of lift pins 167 extend above a substrate receiving surface of the substrate support 122 to lift a substrate 130 and provide access to a backside surface of the substrate 130. When the substrate support 122 is in a raised or processing position, theplurality of lift pins 167 recede beneath the substrate receiving surface of the substrate support 122 to allow the substrate 130 to rest thereon.

[0020] The precursor delivery system 104 as illustrated includes one or more optional remote plasma sources, e.g., a radical generator 106, a deposition precursor source 140, and a conduit system 194 fluidly coupling the radical generator 106 and the deposition precursor source 140 to the chamber lid assembly 110. The precursor delivery system 104 further includes a plurality of isolation valves. For example, an isolation valve of the plurality of isolation valves may be disposed between the radical generator 106 and the inlet 123, which may be used to fluidly isolate the radical generator 106 from the processing chamber 102.

[0021] The radical generator 106 includes a plasma chamber volume 181 . The radical generator 106 is coupled to a power supply 193. The power supply 193 are used to ignite and maintain a plasma of gases delivered to the plasma chamber volume 181 from a gas source 187. The radical generator 106 may be used to generate cleaning radicals used in a chamber clean process by igniting and maintaining a cleaning plasma from a halogencontaining gas mixture delivered to the plasma chamber volume 181 from the gas source 187. In one or more embodiments, a valve 191 is fluidly coupled between the gas source 187 and the plasma chamber volume 181 .

[0022] Suitable remote plasma sources which may be used for radical generator 106 include radio frequency (RF) or very high radio frequency (VHRF) capacitively-coupled plasma (CCP) sources, inductively coupled plasma (ICP) sources, microwave-induced (MW) plasma sources, electron cyclotron resonance (ECR) chambers, or high-density plasma (HDP) chambers.

[0023] As shown, the radical generator 106 is fluidly coupled to the processing chamber 102 by use of a plurality of conduits which extend upwardly from the inlet 123 to connect with an outlet of the plasma chamber volume 181. A valve 190 is used to selectively fluidly isolate the radical generator 106 from the processing chamber 102 and the other portions of the precursor delivery system 104. Typically, the valve 190 is closed during the chamber clean process to prevent activated cleaning gases, e.g., halogenradicals, from flowing into the plasma chamber volume 181 and damaging the surfaces thereof.

[0024] The radical generator 106 and the valve 190 may be arranged so that a treatment plasma in the plasma chamber volume 181 is not disposed in a direct line-of- sight with the inlet 123. The plasma chamber volume 181 may be disposed in alignment with the inlet 123 to provide a direct line-of-sight from the treatment plasma through the inlet 123 and into the processing chamber 102. The direct line-of-sight may beneficially reduce undesired recombination of the treatment radicals by reducing gas-phase collisions therebetween.

[0025] It is contemplated that the processing chamber 102 may optionally be configured as a capacitively coupled plasma processing chamber. In such a case, the RF source may be coupled to the showerhead 118 or another component of the chamber lid assembly 110, to facilitate plasma generation within the processing chamber 102.

[0026] Operation of the substrate processing system 100 is facilitated by the system controller 108. The system controller 108 includes a programmable central processing unit (CPU) 195, which is operable with a memory 196, which may be a non-volatile memory, and support circuits 197. The CPU 195 is one of any form of general-purpose computer processor used in an industrial setting, such as a programmable logic controller (PLC), for controlling various chamber components and sub-processors. The memory 196, coupled to the CPU 195, facilitates the operation of the processing chamber. The support circuits 197 are conventionally coupled to the CPU 195 and comprise cache, clock circuits, input / output subsystems, power supplies, and the like, and combinations thereof coupled to the various components of the substrate processing system 100 to facilitate control of substrate processing operations therewith.

[0027] The instructions in memory 196 are in the form of a program product, such as a program that implements the methods of the present disclosure. In one example, the disclosure may be implemented as a program product stored on computer-readable storage media for use with a computer system. The programs of the program product define functions of the embodiments (including the methods described herein). Thus, the computer-readable storage media, when carrying computer-readable instructions thatdirect the functions of the methods described herein, are embodiments of the present disclosure.

[0028] Figure 2 illustrates a method of depositing a tungsten-containing layer onto a substrate in a processing chamber, such as the processing chamber 102 of Figure 1. In operation 202, the processing chamber 102 is cleaned using a radical-rich cleaning gas, such as NF3mixed with a carrier gas such as argon, helium, and / or krypton, is flowed into the processing volume using the precursor delivery system 104.

[0029] The chamber clean process is used to remove undesirable process residue, e.g., accumulated tungsten residue, from the interior surfaces of the processing volume 115. In some embodiments, the chamber clean process is performed after a number of substrates sequentially processed in the processing chamber 102 is greater than or equal to a threshold value, such as greater than or equal to 2 substrates or more, 3 substrates or more, 5 substrates or more, 7 substrates or more, 9 substrates or more, or 11 substrates or more. In some embodiments, the chamber clean process is performed after every substrate 130 processed in the processing chamber 102.

[0030] At operation 202 of the method 200, the chamber clean process generally includes activating a cleaning gas in a remote plasma source, and flowing the activated cleaning gas into the processing chamber 102. Typically, the cleaning gas mixture includes a halogen-containing gas and a carrier gas, such as argon or helium. Examples of suitable halogen-containing gases which may be used in the cleaning gas mixture include NF3, F2, SFe, CI2, CF4, C2F6, C4F8, CHF3, CFe, CCI4, C2CI6, and combinations thereof. In some embodiments, the cleaning gas further comprises a diluent gas, such as Ar, He, or combinations thereof. For example, in one embodiment, the cleaning gas mixture comprises NF3and Ar or He. Typically, the activated species of the cleaning gas mixture, e.g., halogen radicals, react with tungsten residue accumulated on surfaces of the processing chamber 102 to form a volatile tungsten species. The volatile tungsten species are evacuated from the processing volume 115 through the exhaust 117.

[0031] In some embodiments, a flow rate of the cleaning gas mixture into the remote plasma source, and thus a flow rate of the activated cleaning gas mixture into the processing volume 115, is about 1000 seem or more, such as about 1500 seem or more,about 2000 seem or more, or about 2500 seem or more. The concentration of halogencontaining gas in the cleaning gas mixture is typically between about 5 vol.% and about 95 vol. %, such as between about 5 vol.% and about 70 vol. %, about 10 vol.% and about 95 vol. %, or more than about 10 vol. %.

[0032] In some embodiments, the activated cleaning gas mixture is flowed into the processing volume 115 for a duration of about 5 seconds or more, about 10 seconds or more, about 15 seconds or more.

[0033] The chamber clean process includes flowing the cleaning gas mixture into the radical generator 106, igniting and maintaining a cleaning plasma of the cleaning gas mixture, and flowing the effluent of the cleaning plasma into the processing volume 115. In some embodiments, the chamber cleaning operation is performed after a plurality of substrates 130 have been processed in the chamber so that an average number of substrates processed between chamber cleaning operations is about 2 substrates or more, such as about 5 substrates or more, about 10 substrates or more, about 15 substrates or more, or about 20 substrates or more. In some embodiments, the chamber clean process is performed after every substrate 130 processed in the processing chamber 102.

[0034] For example, the radical generator may be a radical-rich argon (Ar) and nitrogen trifluoride (NF3) second radical generator, utilizes a blend of Ar and NF3 gases to initiate plasma generation. This particular type of plasma source demonstrates remarkable efficacy in the removal of organic contaminants, such as photoresist residue and polymer films. The cleaning process unfolds by propelling the Ar+NFs plasma through the chamber designated for cleaning at a reduced pressure level. The reactive species within in the plasma react with the contaminants adhering to the chamber walls, thereby creating volatile compounds that are subsequently evacuated from the system. Following this stage, the processing chamber 102 undergoes a rinsing procedure involving the introduction of a pure gas, such as argon or nitrogen, to effectuate the removal of any residual contaminants that may persist.

[0035] An example of the chamber cleaning process using the radical generator 106, e.g., the radical-rich Ar+NFs second radical generator, may include evacuating thechamber to achieve a state of low pressure. Subsequently, generating the Ar+NFs plasma within the radical generator 106 then transporting the plasma to the target chamber through a vacuum tube. The reactive species present in the plasma and the contaminants adhering to the chamber walls react, resulting in the creation of volatile compounds. These volatile compounds are then exhausted from the system. The chamber may be rinsed with a pure gas, such as argon or nitrogen, for the purpose of eradicating any residual contaminants that may remain.

[0036] In some embodiments, the processing volume within the processing chamber 102, including the substrate support 122, is exposed to a non-oxygen containing gas to season the processing chamber 102. In some embodiments, a non-oxygen containing gas layer is deposited onto the internal surfaces of the processing chamber 102. For example, a silicon-containing gas may be reacted with an oxygen-containing gas in the processing chamber 102 to produce silicon oxide (SiO2). In some embodiments, a nonoxygen containing gas can include silicon nitride (SisN4), carbon, amorphous boron, and boron nitride (BN). In some embodiments, the non-oxygen containing gas layer can serve as a protective barrier, effectively isolating the processing chamber 102 surfaces from the process precursors and reactants, thereby impeding the adhesion of contaminants to the processing chamber 102 surfaces and mitigates their incorporation into the deposited or etched films.

[0037] At operation 204, the processing volume within the processing chamber 102, including the substrate support 122, is seasoned. In some embodiments, seasoning the processing chamber 102 can include introducing a non-oxygen containing gas and depositing a non-oxygen containing gas layer onto the internal surfaces of the processing chamber 102. In some embodiments, the seasoning can provide a layer including silicon nitride (SisN4), carbon, amorphous boron, and boron nitride (BN). In some embodiments, seasoning the processing chamber 102 can include reacting a silicon-containing gas with an oxygen-containing gas within the confines of the processing chamber 102 to produce silicon oxide (SiC ). The seasoning process includes introducing the non-oxygen containing gas and / or the silicon containing gas to the processing chamber at about 20 to about 2,000 seem. The non-oxygen containing gas and / or the silicon containing gas isintroduced to the processing chamber at a pressure of about 2 Torr to about 30 Torr, and a temperature of about 300 °C to about 650 °C.

[0038] At operation 206, pre-treatment processes are performed within the processing chamber 102. These processes are conducted on the substrate 130 before the desired film deposition, with the objective of preparing the substrate surface. Various types of pre-treatments are available for use in chemical vapor deposition (CVD), and the selection of a particular pre-treatment method depends on factors such as the substrate 130 material, the desired film material, and the specific deposition conditions. Pre-treatments may include chemical etching, which involves exposing the substrate 130 to chemical solutions that can either remove contaminants or modify the surface. Pre-treatments can include ion bombardment, involving bombarding the substrate 130 with ions to either eliminate contaminants or induce surface roughness. Pre-treatments can include annealing prior to deposition by heating the substrate 130 to high temperatures to eliminate contaminants and improve surface properties.

[0039] In some embodiments, the pre-treatment may include chemical etching to modify the substrate surface, e.g., eliminating native oxide layers using hydrofluoric acid. Ion bombardment may be employed to roughen the substrate 130 surface, enhancing the number of nucleation sites for tungsten growth. Annealing in a hydrogen atmosphere can improve substrate 130 surface properties by removing contaminants and establishing a clean, atomically flat surface. The pretreatment step may include using a cyclic N2+H2+Ar plasma treatment along with a fluoride free tungsten precursor to clean and prepare the surface of a substrate 130 surface, to enhance adhesion.

[0040] In some embodiments, the N2+H2+Ar plasma treatment can involve a dry cleaning procedure employing plasma to eliminate contaminants from the surface of the substrate 130. Plasma generation can be accomplished by the application of a high voltage to a mixture of nitrogen (N2), hydrogen (H2), and argon (Ar) gases. The energetic species within the plasma can interact with the contaminants adorning the surface of the substrate 130, leading to the formation of volatile compounds that are subsequently evacuated from the system. The plasma may be remotely-generated, generated in situ as a capacitively coupled plasma, or a combination thereof.

[0041] In some embodiments, tungsten hexafluoride (WFe) may be used as a pretreatment process to provide a wet cleaning method that cleanses the surface of the substrate 130. WFe may be dissolved in a solvent, and the substrate 130 may be immersed in the solution. During this immersion, WFe can engage in reactions with the contaminants on the surface of the substrate 130, generating volatile compounds that dissolve within the solvent medium. In some embodiments, the N2+H2+Ar plasma treatment may follow the WFe soak to eliminate any residual WFe or other lingering contaminants from the surface of the substrate 130. In some embodiments, the WFe soak and the N2+H2+Ar plasma treatment may be cycled according to a number of cycles such that the surface of the substrate 130 is cleaned and / or prepared.

[0042] This multifaceted pretreatment operation offers several advantages, including the comprehensive removal of an array of contaminants from the surface of the substrate 130, encompassing organic, metal, and particle contaminants. Additionally, the pretreatment operation enhances the adhesion and uniformity of the films to be deposited or etched while simultaneously diminishing the likelihood of defects in the resultant films.

[0043] Optionally, at operation 208, an initiation layer can be deposited onto the substrate. In some embodiments, the initiation layer can include a silicon based layer, e.g., silicon oxide, silicon nitride, and / or silicon carbide. In some embodiments, the initiation layer can include a boron based layer, amorphous boron and / or boron nitride. In some embodiments, the initiation layer can include a tungsten based layer, e.g. tungsten boron and / or tungsten nitride. The initiation layer can be deposited in the presence of one or more processing gases, e.g., ammonia, nitrogen, hydrogen, and propene. The initiation layer can be deposited by flowing one or more precursors, e.g., silicon based precursors such as silane, boron based precursors such as diborane, tungsten based precursors such as tungsten fluoride, and / or a processing gas such as ammonia, nitrogen, hydrogen, and propene into the processing chamber 102 at a pressure of about 2 Torr to about 60 Torr, and a temperature of about 300 °C to about 650 °C. In one or more embodiments, the flow rate of the silicon based precurspors is between about 2 seem and about 1000 seem. The flow rat of the hydrogen gas is from about 0 slm to about 15 slm. The flow rate of the ammonia is from about 0 slm to about 5 slm. The flow rate of the nitrogen is from about 0 slm to about 20 slm. Optionally, a high frequency radio frequency of up to 2 kWmay be provided to the processing chamber 102. In such an example, the precursor gases may be ionized into a plasma in situ as a capacitively coupled plasma, or may be ionized remotely. In some embodiments, the initiation layer can be deposited using one or more of thermal CVD, PECVD, or ALD processes. The initiation layer can include a thickness of about 50 A to about 1 ,000 A. Without being bound by theory, the initiation layer may be formed to minimize the initiation layer thickness, while maintaining sufficient adhesion between the film and the substrate.

[0044] For example, an initiation layer of boron nitride can be deposited using thermal boron deposition and H2+N2 capacitively coupled plasma processes. For example, an initiation layer of tungsten nitride can be deposited using WFe soak and H2+N2 capacitively coupled plasma processes. As a further example, the tungsten nitride can be deposited using PECVD processes, e.g., 13.56 MHz frequency operating at a power of about 700 W to about 2kW. As a further example, an initiation layer of tungsten boride can be deposited using thermal tungsten boron deposition and chemical vapor deposition processes. As a further example, the initiation layer can include a combination of layers, e.g., a first layer of tungsten nitride and a second layer of tungsten boron carbide.

[0045] Without being bound by theory, the initiation layer, having a thickness of about 50 A to about 1 ,000 A, can prevent a fluorinated species, e.g., tungsten (VI) fluoride, from etching one or more of the surfaces of the substrate. Additionally, and without being bound by theory, the initiation layer can provide enhanced adhesion between the substrate and the tungsten-containing layer as described below. Moreover, the initiation layer can accelerate the deposition by minimizing nucleation delay or it could improve film roughness by controlling nucleation density.

[0046] At operation 210, a tungsten-containing layer is deposited onto the substrate 130. In some embodiments, the tungsten-containing layer can include a WxSiyNz layer, where x is a value from 1 to 100, y is a value from 1 to 100, and z is a value from 0 to 100. For example, the tungsten-containing layer can include tungsten silicide (WSi) and / or tungsten silicide nitride (WSiN). In some embodiments, the tungsten-containing layer can include about 1 wt% to about 80 wt% of tungsten, e.g., about 1 wt% to about 75 wt%, about 20 wt% to about 70 wt%, or about 30 wt% to about 70 wt%. In some embodiments, the thickness of the tungsten-containing layer can be about 10 nm to about 500 nm, e.g.,about 10 nm to about 200 nm, about 28 nm to about 196 nm, about 43 nm to about 196 nm, or about 50 nm to about 100 nm. Without being bound by theory, by depositing the tungsten-containing layer onto the substrate 130 using a chemical vapor deposition process, and / or a plasma enhanced chemical vapor deposition process the thickness of the tungsten-containing layer can better controlled compared to conventional deposition processes, e.g., atomic layer deposition and / or physical vapor deposition.

[0047] In some embodiments, the tungsten-containing layer can include a grain size of less than or equal to 100 A, e.g., about 0.1 A to about 85 A, such as about 1 A to about 30 A, about 1 A to about 27 A, or about 1 A to about 15 A. In some embodiments, the thickness of the tungsten-containing layer can be about 10 nm to about 500 nm, e.g., about 10 nm to about 200 nm, about 28 nm to about 196 nm, about 43 nm to about 196 nm, or about 50 nm to about 100 nm. Without being bound by theory, by depositing the tungsten-containing layer onto the substrate 130 using a chemical vapor deposition process, and / or a plasma enhanced chemical vapor deposition process the thickness of the tungsten-containing layer can better controlled compared to conventional deposition processes, e.g., atomic layer deposition and / or physical vapor deposition.

[0048] In some embodiments, deposition may occur by introducing a silicon-containing composition and a tungsten-containing composition into the processing chamber 102. In some embodiments, the silicon-containing composition can include silane, a halogenated silane, e.g., dichlorosilane and / or trichlorosilane, and / or an organosilane, e.g., tetramethylsilane. In some embodiments, the silicon-containing composition can be introduced into the processing chamber 102 at a flow rate of about 2 seem to about 1000 seem, e.g., about 2 seem to about 800 seem, about 50 seem to about 700 seem, about 100 seem to about 600 seem, about 200 seem to about 500 seem, or about 300 seem to about 400 seem.

[0049] In some embodiments, the tungsten-containing composition can include a halogenated tungsten, e.g., tungsten (VI) fluoride, an organometallic tungsten, e.g., tungsten hexacarbonyl, and / or a tungsten amide, e.g., bis(t-butylimido)- bis(dimethylamido) tungsten or (‘BuN)2(Me2N)2W. In some embodiments, the tungsten- containing composition can be introduced into the processing chamber 102 at a flow rate of about 5 seem to about 5000 seem, e.g., about 5 seem to about 4800 seem, about 500seem to about 4700 seem, about 1500 seem to about 3600 seem, about 2200 seem to about 3000 seem, or about 3000 seem to about 3500 seem.

[0050] For example, the silicon-containing composition can include silane, and the tungsten-containing composition can include tungsten hexacarbonyl. As a further example, the silicon-containing composition can include silane, and the tungsten- containing composition can include bis(t-butylimido)-bis(dimethylamido) tungsten. As a further example, the silicon-containing composition can include dichlorosilane, and the tungsten-containing composition can include tungsten (VI) fluoride. As a further example, the silicon-containing composition can include tetramethylsilane, and the tungsten- containing composition can include tungsten (VI) fluoride.

[0051] In some embodiments, an additive composition may be introduced to the processing chamber 102 with the silicon-containing composition and the tungsten containing composition. In some embodiments, the additive composition can include hydrogen, ammonia, nitrogen, or a combination thereof. In some embodiments, the additive composition can be introduced to the processing chamber 102 at a flow rate of about 0 slm to about 25 slm, e.g., about 0 slm to about 20 slm, about 0 slm to about 15 slm, or about 0 slm to about 5 slm. For example, an additive composition of hydrogen may be introduced to the processing chamber 102 at a flow rate of about 0 slm to about 15 slm. As a further example, an additive composition of ammonia may be introduced to the processing chamber 102 at a flow rate of about 0 slm to about 5 slm. As a further example, an additive composition of nitrogen may be introduced to the processing chamber 102 at a flow rate of about 0 slm to about 20 slm. Without being bound by theory, an additive composition of ammonia and / or nitrogen can promote growth of tungsten silicon nitride, in which the tungsten silicon nitride can provide enhanced uniformity compared to conventional oxide hard masks.

[0052] In some embodiments, an inert composition may be introduced to the processing chamber 102 with the silicon-containing composition and the tungsten containing composition. In some embodiments, the inert composition can include helium, argon, krypton, or a combination thereof. In some embodiments, the inert composition can be introduced to the processing chamber 102 at a flow rate of about 0 slm to about 20 slm, e.g., about 0 slm to about 20 slm, about 0 slm to about 15 slm, or about 0 slm toabout 5 slm. In some embodiments, a capacitively coupled plasma (CCP) operating at an HFRF power of about 5 W to about 3000 W, e.g., about 5 W to about 2500 W, about 10 W to about 2000 W, about 100 W to about 1500 W, or about 500 W to about 1000 W, may be utilized during the introduction of the tungsten-containing composition and the silicon- containing composition.

[0053] In some embodiments, the processing chamber can be operated at a temperature of about 250 °C to about 700 °C, e.g., about 300 °C to about 650 °C, about 350 °C to about 500 °C, or about 400 °C to about 450 °C. Without being bound by theory, a temperature range of about 250 °C to about 700 °C can allow for processing substrates at higher temperatures while maintaining uniformities of the tungsten-containing layer. In some embodiments, the processing chamber 102 can be operated at a pressure of about 1 Torr to about 350 Torr, e.g., about 2 Torr to about 300 Torr, about 2 Torr to about 200 Torr, about 2 Torr to about 100 Torr, or about 2 Torr to about 30 Torr.

[0054] In some embodiments, operation 210 can optionally include annealing the tungsten-containing layer and the substrate. For example, the substrate 130 and tungsten-containing layer may undergo gas annealing. This includes subjecting the substrate 130 to heating within a pressurized processing chamber 102 containing gas. Without being bound by theory, the presence of this gas can safeguard the substrate 130 from oxidation and facilitate even heating. Gas annealing serves as a means to enhance the properties of materials, encompassing aspects like crystallinity, electrical conductivity, and mechanical strength.

[0055] After deposition, a designated gas is introduced into the processing chamber 102. The designated gas may be any suitable gas, such as hydrogen (H2) or nitrogen (N2). Heating may then be applied to elevate the processing chamber 102 temperature to the annealing temperature of about 550 °C to about 650 °C. The substrate 130 can remain at the annealing temperature for a predetermined period, such as about 0.5 minutes to about 60 minutes, such as about 1 minute to about 30 minutes. Following this, cooling may be initiated to return the processing chamber 102 to room temperature, accompanied by the release of gas from the processing chamber 102. Without being bound by theory, gas annealing within a processing chamber 102 can provide protection of the substrate 130 against oxidation, promotion of uniform heating, adaptability forannealing a diverse array of materials, and the facilitation of precise control over the annealing process. In one example, the optional annealing operation may occur at a processing chamber pressure higher than that of the deposition process of operation 208.

[0056] In some embodiments, the method 200 may then optionally repeat operation 202-210. In some embodiments, and following the optionally repeating operations 202- 210, the substrate 130 can then be removed from the processing chamber 102.

[0057] Figure 3 is a graphical representation of a tungsten-containing layer deposited over a substrate, according to embodiments of the present disclosure. A first tungsten- containing layer (Example 1 ), a second tungsten-containing layer (Example 2), and a third tungsten-containing layer (Example 3) were prepared by flowing about 100 seem to about 1000 seem carrier gas, e.g., argon, about 1 seem to about 10 seem of a silane, about 1 seem to about 10 seem of tungsten hexacarbonyl, and about 1 slm to about 10 slm of hydrogen and nitrogen into a processing chamber. The processing chamber was operated at a temperature of about 500 to about 600 and a pressure of about 5 Torr to about 15 Torr. The first tungsten-containing layer included about 33 wt% tungsten, 65 wt% silicon, 1.4 wt% oxygen, and 0.1 wt% carbon. The second tungsten-containing layer included about 52 wt% tungsten, 34 wt% silicon, 13 wt% oxygen, and 0 wt% carbon. The third tungsten-containing layer included about 68 wt% tungsten, 27 wt% silicon, 2 wt% oxygen, and 0 wt% carbon.

[0058] Example 1 resulted in a tungsten-containing layer having a thickness of about 197 nm, having a gain size of about 23 A to about 100 A, in which Example 1 had a larger range of grain sizes compared to Examples 2 and 3. Example 2 resulted in a reduced thickness of about 433 A, having a grain size of about 27 A. Example 3 resulted in the lowest thickness of about 289 A, having a grain size of about 15 A. Without being bound by theory, an increase in the concentration of tungsten in the tungsten-containing layer can result in an increase in the uniformity of the tungsten-containing layer.

[0059] Figure 4 is a schematic cross sectional view of a process chamber 400 configured according to various embodiments of the present disclosure. By way of example, the embodiment of the process chamber 400 in Figure 4 is described in terms of a PECVD system, but any other process chamber may fall within the scope of theembodiments, including other plasma deposition chambers or plasma etch chambers. The process chamber 400 includes a chamber body 402, a lid assembly 406, and a substrate support 405. The lid assembly 406 is disposed at an upper end of and is supported by the chamber body 402, and the substrate support 405 is at least partially disposed within the chamber body 402. The chamber body 402, lid assembly 406, and substrate support 405 together define a processing volume 446 within the process chamber 400 in which a substrate 426 may be processed. The processing volume 446 may be accessed through a port 404 formed in the chamber body 402 that facilitates transfer of a substrate into and out of the processing volume 446 of the process chamber 400.

[0060] The lid assembly 406 includes a gas distributor 408, a modulation electrode 410, and insulators 412. In some embodiments, the modulation electrode 410 is optional. The insulator 412, which may be a dielectric material such as a ceramic or metal oxide, for example aluminum oxide and / or aluminum nitride. The insulator 412 contacts the modulation electrode 410 and separates the modulation electrode 410 electrically and thermally from the gas distributor 408 and from the chamber body 402. The gas distributor 408 (e.g., showerhead) has passages 414 therethrough for admitting process gas into the processing volume 446. A pair of insulators (e.g., annular insulators) are disposed between the gas distributor 408 and the modulation electrode 410. The modulation electrode 410 is annular and circumscribes the processing volume 446.

[0061] Process gases (e.g., one or more precursor and one or more inert carrier gas) may be provided through the conduit 420 from a gas source 422 to be introduced into the process chamber 400. The processing gas from the conduit 420 enters the processing volume 446 through the passages 414 in the gas distributor 408 such that the processing gas is uniformly distributed in the processing volume 446. In one embodiment, the passages 414 in the gas distributor 408 may be radially distributed and gas flow to each of the passages 414 may be separately controlled to further facilitate gas uniformity within the processing volume 446.

[0062] The processing gases can be evacuated from the processing volume 446 through an outlet 418 which may be located at any convenient location along the chamber body 402. In some embodiments, the outlet 418 may be associated with a vacuum pump(not shown) fluidly coupled to the processing volume 446. The vacuum pump may be part of the gas and pressure control system of the processing chamber 400.

[0063] In some embodiments, portions of the gas distributor 408 may be heated using a resistive heater (not shown) or thermal fluid disposed in a conduit (not shown) through a portion of the gas distributor 408 or otherwise in direct contact or thermal contact with the gas distributor 408. The conduit may be disposed through an edge portion of the gas distributor 408 to avoid disturbing the gas flow function of the gas distributor 408. Heating the edge portion of the gas distributor 408 may be useful to reduce the tendency of the edge portion of the gas distributor 408 to be a heatsink within the process chamber 400.

[0064] In some embodiments, the walls of the chamber body 402 may also be heated to similar effect. Heating the chamber surfaces exposed to the plasma also minimizes deposition, condensation, and / or reverse sublimation on the chamber surfaces, reducing the cleaning frequency of the chamber and increasing mean cycles per clean. Higher temperature surfaces also promote dense deposition that is less likely to produce particles that fall onto a substrate. Thermal control conduits with resistive heaters and / or thermal fluids (not shown) may be disposed through the chamber walls to achieve thermal control of the chamber walls. Temperature of all surfaces may be controlled by a controller.

[0065] In some embodiments, the gas distributor 408 may be coupled to a RF power source 416, such as a RF generator, as shown in Figure 4. DC power, pulsed DC power, and pulsed RF power source may alternatively be used. In other embodiments, the gas distributor 408 may be coupled to ground. The RF power source 416 is electrically connected to the gas distributor 408 and is configured to apply a RF potential to the gas distributor 408 to facilitate the generation of plasma in the interior processing volume 446. In some embodiments, the RF power source 416 may be a high frequency RF power source (“HFRF power source”) capable of generating an HFRF power (e.g., at a frequency of about 10 MHz to about 40 MHz, e.g., about 20 MHz to about 22 MHz, about 22 MHz to about 24 MHz, about 24 MHz to about 26 MHz, about 26 MHz to about 28 MHz, or about 28 MHz to about 30 MHz). The HFRF power source can be designed for use with a fixed match and can regulate the power delivered to the load, eliminating concerns about forward and reflected power. Without being bound by theory, an HFRF power source of about 26 MHz to about 28 MHz can provide an increase in the C2H production rate and Hproduction rate, thereby producing a more conformal and / or uniform carbon gapfill in trenches between one or more features, and reducing pattern loading effects. The HFRF power enables increased radical flux during generation of the plasma in the interior processing volume 446, while also enabling a decrease in the pressure in the processing volume. An overall increase in power enables an overall increase in flux. An increase in the power and an increase in pressure enables in an increase in radical flux.

[0066] In other embodiments, the RF power source 416 may be a low frequency RF power source (“LFRF power source”) capable of generating an LFRF power (e.g., at a frequency of about 350 kHz). The LFRF power source can provide both low frequency generation and fixed match elements. The LFRF, in combination with higher pressure, enables increased radical flux during the generation of the plasma in the interior processing volume 446.

[0067] In further embodiments, an additional power source (not shown) may be added with the RF power source 416 to provide a dual RF power source to the process chamber 400. The modulation electrode 410 may be coupled to a tuning circuit 444 that controls an impedance of an electrical path from the modulation electrode 410 to an electrical ground. The tuning circuit 444 may include an electronic sensor 448 and an electronic controller, which may be a variable capacitor 450 as shown that is controllable by the electronic sensor 448. The tuning circuit 444 may be an LLC circuit comprising one or more inductors 452. The electronic sensor 448 may be a voltage or current sensor and may be coupled to the variable capacitor 450 to afford a degree of closed-loop control of plasma conditions inside the processing volume 446. In some embodiments, the tuning circuit 444 may be any circuit that features a variable or controllable impedance under the plasma conditions present in the processing volume 446 during processing.

[0068] The substrate support 405 may be disposed within the process chamber 400. The substrate support 405 may support the substrate 426 during processing. A first electrode 460 and a second electrode 462 are disposed in and / or on the substrate support 405. Further, in some embodiments, a heater element (not shown) may be embedded in the substrate support 405. The heater element can be operable to controllably heat the substrate support 405 and the substrate 426 positioned thereon to a target temperature,such as to maintain the substrate 426 at a temperature in a range from about 350 degrees Celsius to about 500 degrees Celsius.

[0069] The substrate support 405 is coupled to a shaft 466 for support. The shaft 466 can provide a conduit from a gas source 468 and electrical and temperature monitoring leads (not shown) between the substrate support 405 and other components of the process chamber 400. In some examples, a purge gas may be provided from the gas source 468 to the backside of the substrate 426 through one or more purge gas inlets 469 connected to the substrate support 405. The purge gas flowed toward the backside of the substrate 426 can help prevent particle contamination caused by deposition on the backside of the substrate 426. The purge gas may also be used as a form of temperature control to cool the backside of the substrate 426. Although not illustrated, the shaft 466 may be coupled to an actuator (not shown) which extends through a centrally-located opening formed in a bottom of the chamber body 402. The actuator may be flexibly sealed to the chamber body 402 by bellows (not shown) that prevent vacuum leakage from around the shaft 466. The actuator can allow the substrate support 405 to be moved vertically within the chamber body 402 between a process position and a lower, transfer position. The transfer position is slightly below the port 404 in the chamber body 402. In operation, the substrate support 405 may be elevated to a position in close proximity to the lid assembly 406 for processing.

[0070] The first electrode 460 may be embedded within the substrate support 405 or coupled to a surface of the substrate support 405. The first electrode 460 may be a plate, a perforated plate, a mesh, a wire screen, or any other distributed arrangement. The first electrode 460 may be a tuning electrode and may be coupled to a tuning circuit 470. The tuning circuit 470 may have an electronic sensor 472 and an electronic controller, such as a variable capacitor 474 electrically connected between the first electrode 460 and an electrical ground. The electronic sensor 472 may be a voltage or current sensor and may be coupled to the variable capacitor 474 to provide further control over plasma conditions in the processing volume 446.

[0071] The second electrode 462, which may be a bias electrode and / or an electrostatic chucking electrode, may be coupled to the substrate support 405. The second electrode 462 may be coupled to a bias power source 476 through an impedancematching circuit 478. The bias power source 476 may be DC power, pulsed DC power, RF power, pulsed RF power, or a combination thereof (e.g., pulsing HFRF or continuous wave HFRF).

[0072] In operation, the substrate 426 is disposed on the substrate support 405, and process gases are flowed through the lid assembly 406 according to any desired flow plan. Electric power is coupled to the gas distributor to establish a plasma in the processing volume 446. The substrate 426 may be subjected to an electrical bias using the bias power source 476, if desired.

[0073] Upon energizing a plasma in the processing volume 446, a potential difference is established between the plasma and the modulation electrode 410. A potential difference is also established between the plasma and the first electrode 460. The variable capacitors 450 and 474 may then be used to adjust the impedances of the paths to an electrical ground represented by the tuning circuits 444 and 470. A set point may be delivered to the tuning circuit 444 and 470 to provide independent control of the plasma density uniformity from center to edge and deposition rate. The electronic sensors may adjust the variable capacitors to maximize deposition rate and minimize thickness nonuniformity independently. The components implemented to control temperature and uniformity of the plasma, among other, can permit deposition of a highly conformal layer on a substrate being processed, even within small gaps.

[0074] Overall, the methods described herein can allow for a tungsten-containing layer to be deposited on a substrate, in which the tungsten-containing layer includes a thickness of about 10 nm to about 500 nm. The tungsten-containing layers can include a grain size of less than 15 A, thereby increasing the uniformity of the tungsten-containing layer compared to conventional PVD and / or ALD processes. Moreover, the tungsten-containing layer can include enhanced adhesion due to the absence of fluorinated tungsten precursors, thereby reducing etching and / or chemical reactions with the substrate surface. The tungsten-containing layer can be controlled to provide larger ranges of compositions of WxSiyNz films, compared to conventional deposition processes, e.g., PVD processes and / or ALD processes. A reduction in the cleaning and / or maintenance can be achieved due to the use of a remote plasma source to clean the deposition chamber. Moreover, a reduction in the number of particles and / or contamination occurs due to theremote plasma source with methods described herein compared to PVD processes. A reduction in the number of particles can increase device yield. The methods described herein can provide improved grain size, e.g., below 1 % to 2%, compared to conventional PVD and / or ALD processes, where improved grain size can improve critical dimension uniformity after etching. Moreover, a reduction in manufacturing costs occurs when producing devices uses the methods described herein

[0075] When introducing elements of the present disclosure or exemplary aspects or embodiments thereof, the articles “a,” “an,” “the” and “said” are intended to mean that there are one or more of the elements.

[0076] The terms “comprising,” “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.

[0077] The term “coupled” is used herein to refer to the direct or indirect coupling between two objects. For example, if object A physically touches object B and object B touches object C, the objects A and C may still be considered coupled to one another — even if objects A and C do not directly physically touch each other. For instance, a fist object may be coupled to a second object even though the first object is never directly in physical contact with the second object.

[0078] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

What is claimed is:1 . A substrate processing system, comprising: a processing chamber defining a processing volume; a precursor delivery system fluidly coupled to the processing chamber; and a controller having instructions stored thereon for performing a method of processing a plurality of substrates when executed by one or more processors, the method comprising: cleaning the processing chamber; seasoning the processing chamber; receiving a substrate into the processing volume of the processing chamber fluidly coupled to the precursor delivery system; performing a pre-treatment process on the substrate within the processing chamber; and depositing a tungsten-containing layer onto the substrate.

2. The substrate processing system of claim 1 , wherein depositing the tungsten- containing layer comprises introducing a silicon-containing composition and a tungsten- containing composition.

3. The substrate processing system of claim 2, wherein the silicon-containing composition comprises a silane, a halogenated silane, or an organosilane.

4. The substrate processing system of claim 3, wherein the halogenated silane comprises dichlorosilane or trichlorosilane.

5. The substrate processing system of claim 3, wherein the organosilane comprises tetramethylsilane.

6. The substrate processing system of claim 2, wherein the tungsten-containing composition comprises a halogenated tungsten, an organometallic tungsten, or a tungsten amide.

7. The substrate processing system of claim 6, wherein the halogenated tungsten comprises tungsten (VI) fluoride.

8. The substrate processing system of claim 6, wherein the organometallic tungsten comprises tungsten hexacarbonyl.

9. The substrate processing system of claim 6, wherein the tungsten amide comprises bis(t-butylimido)-bis(dimethylamido) tungsten.

10. The substrate processing system of claim 1 , wherein depositing the tungsten- containing layer comprises using a capacitively-coupled plasma.

11. A precursor delivery system for processing a substrate, comprising: at least one radical generator; and a controller having instructions stored thereon for performing a method of processing a plurality of substrates when executed by one or more processors, the method comprising: cleaning a processing chamber; seasoning the processing chamber, receiving the substrate into a processing volume of the processing chamber fluidly coupled to the precursor delivery system; performing a pre-treatment process on the substrate within the processing chamber; and depositing a tungsten-containing layer onto the substrate.

12. The precursor delivery system of claim 11 , wherein depositing the tungsten- containing layer comprises introducing a silicon-containing composition and a tungsten- containing composition.

13. The precursor delivery system of claim 12, wherein the silicon-containing composition comprises a silane, a halogenated silane, or an organosilane.

14. The precursor delivery system of claim 12, wherein the tungsten-containing composition comprises a halogenated tungsten, an organometallic tungsten, or a tungsten amide.

15. The precursor delivery system of claim 11 , wherein depositing the tungsten- containing layer comprises using a capacitively-coupled plasma.

16. A method for forming a tungsten-containing layer on a substrate, comprising: cleaning a processing chamber; seasoning the processing chamber, receiving the substrate into a processing volume of the processing chamber fluidly coupled to a precursor delivery system; performing a pre-treatment process on the substrate within the processing chamber; and depositing the tungsten-containing layer onto the substrate.

17. The method of claim 16, wherein depositing the tungsten-containing layer comprises introducing a silicon-containing composition and a tungsten-containing composition.

18. The method of claim 17, wherein the silicon-containing composition is introduced at a first flow rate of about 5 seem to about 5000 seem, and the tungsten-containing composition is introduced at a second flow rate of about 2 seem to about 1000 seem.

19. The method of claim 16, wherein depositing the tungsten-containing layer comprises operating the processing chamber at a pressure of about 1 Torr to about 350 Torr, and a temperature of about 250 °C to about 700 °C.

20. The method of claim 16, wherein depositing the tungsten-containing layer comprises using a capacitively-coupled plasma at a power of about 5 W to about 3000 W.

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