Carbon gapfill

Abstract

Examples are disclosed that relate to carbon gapfill using plasma enhanced chemical vapor deposition (PECVD) with multifrequency radiofrequency power. One example provides a method of filling a gap on a substrate disposed in a processing chamber. The method comprises flowing a carbon-containing precursor into the processing chamber. The method further comprises flowing one or more of a passivation agent or an etching agent into the processing chamber. The method further comprises forming a radiofrequency (RE) plasma using RF power to convert the carbon-containing precursor into a carbon film in the gap. The RF power comprises a first RF power component and a second RF power component, the first RF power component comprising a frequency within a range of 400 kHz to 3 MHz and the second RF power component comprising a frequency within a range of 3 MHz to 300 MHz.

Description

CARBON GAPFILLBACKGROUND

[0001] Electronic device fabrication processes can involve many steps of material deposition, patterning, and removal to form integrated circuits on substrates. Various methods can be used to deposit films of materials onto a substrate. As one example, chemical vapor deposition (CVD) can be used to deposit a film by exposing a substrate to a flow of gas phase precursors. The gas phase precursors undergo chemical reactions to form a film on the substrate. Plasma-enhanced CVD (PECVD) utilizes a plasma to provide energy for the chemical conversion of the precursors to the film. CVD processes can be used to deposit a wide variety of films, including carbon films.SUMMARY

[0002] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure.

[0003] Examples are disclosed that relate to performing carbon gapfill using plasma enhanced chemical vapor deposition (PECVD) with multifrequency radiofrequency power. One example provides a method of filling a gap on a substrate disposed in a processing chamber. The method comprises flowing a carbon-containing precursor into the processing chamber. The method further comprises flowing one or more of a passivation agent or an etching agent into the processing chamber. The method further comprises forming a radiofrequency (RF) plasma using RF power to convert the carbon-containing precursor into a carbon film in the gap. The RF power comprises a first RF power component and a second RF power component, the first RF power component comprising a frequency within a range of 400 kHz to 3 MHz and the second RF power component comprising a frequency within a range of 3 MHz to 300 MHz.

[0004] In some such examples, the second RF power component comprises a power of 100 W to 1000 W.

[0005] Additionally or alternatively, in some such examples, the first RF power component comprises a power of 200 W to 500 W.

[0006] Additionally or alternatively, in some such examples, the carbon- containing precursor comprises one or more of acetylene, ethylene, or propylene.

[0007] Additionally or alternatively, in some such examples, the one or more of the passivating agent or the etching agent comprises one or more of molecular hydrogen (Fb), ammonia (NH3), carbon dioxide (CO2), carbon monoxide (CO), carbon oxysulfide (COS), molecular oxygen (O2), boron trifluoride (BF3), nitrogen trifluoride (NF3), sulfur dioxide (SO2), sulfur hexafluoride (SFe), a halocarbon gas, a halohydrocarbon gas, a halogen acid (hydrofluoric acid (HF), hydrochloric acid (HC1), hydrobromic acid (HBr), hydroiodic acid (HI)), fluorine (F2), chlorine (Ch), bromine (Bn), or iodine (I2).

[0008] Additionally or alternatively, in some such examples, the method further comprises flowing an inert gas into the processing chamber.

[0009] Additionally or alternatively, in some such examples, the carbon- containing precursor is flowed into the processing chamber through an electrically grounded showerhead, and the RF power is supplied to a substrate support in the processing chamber.

[0010] Additionally or alternatively, in some such examples, the substrate comprises a first region comprising a plurality of gaps at a first feature density and a second region comprising a plurality of gaps at a second feature density different from the first feature density.

[0011] Another example provides a processing tool for depositing a carbon film onto a substrate, the substrate comprising a gap. The processing tool comprises a processing chamber. The processing tool further comprises a substrate support. The processing tool further comprises flow control hardware configured to control processing chemical flow into the processing chamber. The processing tool further comprises an RF power source configured to provide RF power to form a plasma in the processing chamber. The processing tool further comprises a controller operatively coupled to the flow control hardware and the RF power source. The controller is configured to operate the flow control hardware to flow a carbon-containing precursor into the processing chamber. The controller is further configured to operate the flowcontrol hardware to flow one or more of an etching agent or a passivation agent into the processing chamber. The controller is further configured to operate the RF power source to supply RF power to an electrode in the processing chamber, thereby forming a plasma to convert the carbon-containing precursor into a carbon film in the gap, the RF power comprising a first RF power and a second RF power, the first RF power component comprising a frequency within a range of 400 kHz to 3 MHz and the second RF power component comprising a frequency within a range of 3 MHz to 300 MHz.

[0012] In some such examples, the second RF power component comprises a power of 100 W to 1000 W.

[0013] Additionally or alternatively, in some such examples, the first RF power component comprises a power of 200 W to 500 W.

[0014] Additionally or alternatively, in some such examples, the processing tool further comprises a carbon-containing precursor source comprising one or more of acetylene, ethylene, or propylene.

[0015] Additionally or alternatively, in some such examples, the processing tool further comprises one or more of a passivating agent source or an etching agent source, the one or more of the passivating agent source or the etching agent source comprising one or more of molecular hydrogen (H2), ammonia (NH3), carbon dioxide (CO2), carbon monoxide (CO), carbon oxysulfide (COS), molecular oxygen (O2), boron trifluoride (BF3), nitrogen trifluoride (NF3), sulfur dioxide (SO2), sulfur hexafluoride (SFe), a halocarbon gas, a halohydrocarbon gas, a halogen acid (hydrofluoric acid (HF), hydrochloric acid (HC1), hydrobromic acid (HBr), hydroiodic acid (HI)), fluorine (F2), chlorine (Ch), bromine (Bn), or iodine (I2).

[0016] Additionally or alternatively, in some such examples, the controller is further configured to operate the flow control hardware to flow an inert gas into the processing chamber.

[0017] Additionally or alternatively, in some such examples, the processing tool further comprises an electrically grounded showerhead for flowing gases into the processing chamber, and wherein the RF power source is electrically connected to the substrate support.

[0018] Another example provides a processing tool for depositing a carbon film onto a substrate, the substrate comprising a gap. The processing tool comprises a processing chamber. The processing tool further comprises a substrate support comprising a first electrode. The processing tool further comprises a showerheadconfigured for introducing processing chemicals into the processing chamber. The showerhead comprises a second electrode configured as an electric ground. The processing tool further comprises flow control hardware configured to control processing chemical flow through the showerhead into the processing chamber. The processing tool further comprises a RF power source electrically connected to the substrate support, the RF power source configured to form a plasma in the processing chamber. The processing tool further comprises a controller operatively coupled to the flow control hardware, and the RF power source. The controller is configured to operate the flow control hardware to flow a carbon-containing precursor into the processing chamber. The controller is further configured to operate the flow control hardware to flow one or more of an etching agent or a passivation agent into the processing chamber. The controller is further configured to operate the RF power source to supply RF power to an electrode in the processing chamber, thereby forming a plasma to convert the carbon-containing precursor into a carbon film in the gap. The RF power comprises a first RF power and a second RF power, the first RF power component comprising a frequency within a range of 400 kHz to 3 MHz and the second RF power component comprising a frequency within a range of 3 MHz to 300 MHz.

[0019] In some such examples, wherein the second RF power component comprises a power of 100 W to 1000 W.

[0020] Additionally or alternatively, in some such examples, the first RF power component comprises a power of 200 W to 500 W.

[0021] Additionally or alternatively, in some such examples, the processing tool further comprises a carbon-containing precursor source comprising one or more of acetylene, ethylene, or propylene.

[0022] Additionally or alternatively, in some such examples, the processing tool further comprises one or more of a passivating agent source or an etching agent source, the one or more of the passivating agent source or the etching agent source comprising one or more of molecular hydrogen (H2), ammonia (NH3), carbon dioxide (CO2), carbon monoxide (CO), carbon oxysulfide (COS), molecular oxygen (O2), boron trifluoride (BF3), nitrogen trifluoride (NF3), sulfur dioxide (SO2), sulfur hexafluoride (SFe), a halocarbon gas, a halohydrocarbon gas, a halogen acid (hydrofluoric acid (HF), hydrochloric acid (HC1), hydrobromic acid (HBr), hydroiodic acid (HI)), fluorine (F2), chlorine (Ch), bromine (Bn), or iodine (I2).BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIGS. 1A-1D schematically show structures formed by an example single-frequency plasma-enhanced chemical vapor deposition (PECVD) process for depositing a carbon film in a gap that results in top-heavy growth that closes off the gap-

[0024] FIG. 2 schematically shows a structure formed by an example singlefrequency PECVD process for depositing a carbon film in a gap, and which results in feature-density-dependent differential film growth due to top-heavy deposition conditions.

[0025] FIGS. 3A-3B schematically show structures formed by an example single-frequency PECVD process for depositing a carbon film in a gap, and which forms a dent in the carbon overburden due to top-heavy deposition conditions.

[0026] FIG. 4 shows a flow diagram of an example method for filling a gap with a carbon film using a multifrequency PECVD process.

[0027] FIGS. 5A-5D schematically show example substrate structures formed using the method of FIG. 4.

[0028] FIG. 6 schematically shows example substrate structures formed using the method of FIG. 4, and illustrates reduced feature-density-dependent differential film growth compared to FIG. 2.

[0029] FIG. 7 schematically shows an example PECVD tool.

[0030] FIG. 8 shows a block diagram of an example computing system.DETAILED DESCRIPTION

[0031] The term “chemical vapor deposition” (CVD) generally represents a process in which a solid phase film is formed on a substrate by directing a flow of one or more precursor gases over the substrate surface under conditions configured to cause the chemical conversion of the precursor gases to the solid phase film. The term “plasma-enhanced chemical-vapor deposition” (PECVD) generally represents a CVD process in which a plasma is used to facilitate the chemical conversion of one or more precursor gases to a solid phase film on a substrate. The terms “growth”, “deposition”, and variants thereof, also can be used to refer to film formation.

[0032] The term "etching agent" generally represents any material used in a PECVD processing gas mixture to remove materials from a substrate. Example agents include halogen-containing and / or oxygen-containing gases. Example halogen-containing etching agents include chlorine (Ch), fluorine (F2), bromine (Bn), iodine (I2), halogen acids (hydrofluoric acid (HF), hydrochloric acid (HC1), hydrobromic acid (HBr), hydroiodic acid (HI)), nitrogen trifluoride (NF3), boron trifluoride (BF3), sulfur hexafluoride (SFe), halocarbon gases having a general formula CaXb (where X comprises one or more of fluorine, chlorine, bromine, or iodine and where a = 1-10), and halohydrocarbon gases having a general formula CaHbXc (where X comprises one or more of fluorine, chlorine, bromine, or iodine and where a = 1-10). Example oxygencontaining etching agents include carbon monoxide (CO), carbon dioxide (CO2), carbon oxysulfide (COS), sulfur dioxide (SO2), and molecular oxygen (O2).

[0033] The term “gap” generally represents a recessed feature that extends into a substrate from an opening in the substrate surface.

[0034] The term “gas mixture” generally represents a mixture of two or more gases in a processing chamber during a CVD process.

[0035] The term "passivating agent" generally represents a material in a PECVD processing gas mixture that can physisorb or chemisorb to a substrate surface to reduce a rate of PECVD film formation on the substrate surface. Example passivating agents include molecules that can provide hydrogen ions and / or hydrogen radicals when exposed to a plasma. Example passivating agents that can provide hydrogen ions and / or hydrogen radicals include hydrogen-containing molecules. Example hydrogencontaining molecules that can be used as passivating agents include molecular hydrogen (H2), ammonia (NH3), and sulfur dioxide (SO2).

[0036] The term “plasma” generally represents an ionized gas comprising gasphase cations and free electrons.

[0037] The term “processing chamber” generally represents an enclosure in which chemical and / or physical processes are performed on substrates. The pressure, temperature, gas flow rate, and atmospheric composition within a processing chamber can be controllable to perform chemical and / or physical processes.

[0038] The term "profile" generally represents a shape of a deposited film.

[0039] The term “radiofrequency (RF) power” generally represents oscillating electric energy in a radiofrequency regime. The frequency of RF power is within a range of approximately 20 kHz to 300 GHz.

[0040] The term “lower-frequency” (“LF”) RF power generally represents RF power comprising a frequency of 3 MHz or lower.

[0041] The term “higher-frequency” (“HF”) RF power generally represents RF power comprising a frequency of 3 MHz or higher.

[0042] The term “substrate” generally represents any object onto which a film can be deposited in a processing chamber.

[0043] As described above, the fabrication of electronic devices involves many steps of material deposition, patterning, and removal to form integrated circuits and / or memory structures on substrates. For example, some three-dimensional (3D) integrated circuits, such as 3D NAND (Not AND) memory devices, are fabricated using stacked pairs of materials, with the "active" device layer being one of the pairs and the other being a dielectric for electrical isolation. By stacking these pairs of layers, manufacturers are able to create more active layers. A stack of such alternating layers can be referred to as a mold stack. As a more specific example, alternating silicon oxide and silicon nitride layers can be deposited to form an ONON (oxide-nitride-oxide- nitride) mold stack in a 3D NAND fabrication process. In some examples, a mold stack can comprise alternating silicon layers and polysilicon layers (OPOP), where the term polysilicon generally represents polycrystalline silicon. Other examples of 3D integrated circuits include 3D DRAM and 3D NOR memory devices.

[0044] Patterning and device integration in a 3D integrated circuit fabrication process often involves etching holes through a mold stack. However, etching of deep, high aspect ratio features, such as channel holes in a 3D NAND mold stack, can be challenging. Thus, the etching of a deep, high aspect ratio feature can be performed in more than one discrete etching process. In the example of a 3D NAND mold stack, a first set of alternating layers (a first “deck” of the mold stack) can be deposited, and then a first hole can be etched through the first deck. Next, the first hole in the first deck can be plugged with a material having sufficiently high selectivity to the etching process to form an etch stop layer. Carbon is one example of an etch stop layer.

[0045] PECVD can be used to deposit carbon in the channel hole and on surrounding regions of the substrate. Planarization then can be performed to remove the carbon from the surrounding regions of the substrate. Next, a second deck of alternating material layers can be formed over the first deck, including over the deposited carbon. Then, another etching process can be used to etch a hole through the second deck in a location aligned with the hole in the first deck. The etching process slows when it reaches the carbon used as the etch stop layer. This helps to protect the layers of the first deck from the etching chemistry. Then, the carbon can be removed (e.g. by ashing- oxidation to volatile carbon dioxide), thereby joining the holes in the first deck and second deck into a single hole through both decks of the mold stack. An ashing process can be used to remove residual carbon from within the holes. This process then can be repeated for any additional decks of alternating materials.

[0046] The process of filling a gap (e.g., a channel hole) with a material is referred to herein as “gapfill”. As an example carbon PECVD gapfill process, a carbon- containing precursor, such as a hydrocarbon gas, is introduced into a processing chamber. Then, a radiofrequency (RF) plasma is formed using RF power. The RF power comprises a relatively higher frequency greater than 3 MHz, such as a frequency of 13.56 MHz. RF power at higher frequencies helps convert carbon containing precursor into reactive species, including radical species and ions. Thus, the RF plasma facilitates conversion of the carbon-containing precursor into a carbon film within the gap-

[0047] However, depositing high-quality carbon gapfill in deep, high aspect ratio features can be challenging. Various processing conditions can be controlled to help meet gapfill specifications related to film profile, feature-density-dependent differential film growth, and overburden planarity. For example, a typical PECVD process for a deep, high aspect ratio can utilize a passivation agent and / or an etching agent. As described in more detail below, use of a passivation agent and / or an etching agent helps to control the film profile while performing gapfill. Further, the PECVD process can utilize an RF power comprising a low to moderate power, such as a power < 450 W. Such processing conditions can help deposit a high-quality carbon film into a gap. Unless otherwise stated, values for RF power refers to power per station. RF power for a multi-station processing chamber can be scaled accordingly.

[0048] However, carbon film growth under such conditions can be slow. In some examples, deposition rates can be approximately 4 nm / min or less. Use of a relatively higher power (e.g., > 450 W) can increase growth rate of the carbon film. This is because higher power RF power helps produce more ions and radical species in the plasma. However, PECVD using a relatively high power can lead to “top-heavy” growth where deposition on surfaces near the top of a gap is faster than deeper in the gap, even when using a passivating agent and / or etching agent. This can lead to the gap closing prior to filling the gap.

[0049] FIGS. 1A-1D schematically show structures formed in an example PECVD process with top-heavy growth conditions that lead to gap closing. FIG. 1Aschematically shows a substrate 100 comprising gaps 102, 104. Substrate 100 can comprise any suitable material. Examples include silicon, silicon oxide, silicon nitride, silicon oxynitride, silicon oxy carbide, and silicon oxy carbonitride. A carbon film 106 (e.g., an amorphous carbon film) is deposited the substrate 100 and within gaps 102, 104. The PECVD process utilizes RF power > 450 W. Such power levels can provide relatively fast carbon film growth compared to the use of lower power levels. However, at this power level, film growth rates are faster on surfaces near the opening of gaps 102, 104 than at the bottom of the gaps. As a result, carbon film 106 is thicker on field regions 108 than on sidewalls 110 of the gaps 102, 104.

[0050] FIG. IB schematically shows substrate 100 following further PECVD processing to deposit additional carbon film 106. Due to the top-heavy growth of carbon film 106, the opening of gaps 102, 104 are narrowed, as indicated at 112. As a result, less carbon-containing precursor flows into gaps 102, 104. This can further reduce carbon film growth rate in the gaps.

[0051] FIG. 1C schematically shows substrate 100 following further PECVD processing. As carbon film 106 grows thicker, the carbon film closes off gaps 102, 104 and forms voids 114, 116. Once gaps 102, 104 are closed off, further growth of the carbon film in the gaps does not occur. Further, as indicated at 118, the top of the void extends above the top surface of substrate 100 into the carbon overburden 120. This can lead to problems during planarization. FIG. ID schematically shows substrate 100 following an example planarization step to remove the carbon overburden 120. Due to the planarization step, the gaps 102, 104 are re-opened as indicated at 122. This can lead to device failure.

[0052] As mentioned above, use of a passivation agent and / or an etching agent can potentially help avoid issues related to top-heavy deposition. A passivation agent deposits mainly on surfaces near the opening of the gap and acts to slow growth of the carbon film on upper surfaces of the gap. Similarly, an etching agent can etch at least some carbon film. As the etching agent concentration is higher near the opening of the gap and decreases farther within the gap due to consumption of the etching agent, the etching agent also acts to slow film growth on upper surfaces of the gap. Example passivating and etching agents are described below.

[0053] However, when RF plasma conditions comprise relatively higher power to achieve higher deposition rates, the use of the passivating agent and / or the etching agent can be insufficient to avoid top-heavy growth. Further, PECVD processes thatuse higher power RF power still can encounter problems such as feature-density- dependent differential film growth and dent formation. The issue of feature-density- dependent differential film growth is discussed with reference to FIG. 2. FIG. 2 schematically shows an example substrate 200 comprising gaps 202, 204 in a first region 206. Substrate 200 further comprises a field region 208 between gaps 202, 204. Substrate 200 further comprises gaps 212, 214 in a second region 216. Gap 212 is spaced apart from gap 214 with a relatively larger field region 218 therebetween. As such, the second region 216 of substrate 200 comprises a relatively lower feature density than first region 206.

[0054] Substrate 200 further comprises a carbon film 220 deposited onto the substrate by PECVD. FIG. 2 shows substrate 200 in a partially filled state. The PECVD process uses an RF plasma comprising a relatively higher power to deposit the film faster than use of a lower power. Due to top-heavy growth and the difference in feature density, the carbon film 220 is thicker on second region 216 than first region 206. This is because a relatively greater proportion of carbon-containing precursor is deposited into gaps 202, 204 than onto field region 208 of first region 206. In contrast, a relatively lower proportion of carbon-containing precursor is deposited into gaps 212, 214 than onto field region 218 of second region 216. As substrate 200 is in a partially filled state, variations in film thickness on field regions 208, 218 can become more pronounced as carbon film 206 grows thicker. Variations in film thickness due to differences in feature density (referred to herein as “feature-density-dependent differential film growth”) can result in thickness gradients and / or varying thicknesses in a carbon overburden. This can cause problems during planarization and lead to device issues.

[0055] Next, FIGS. 3A-3B schematically illustrate denting in a carbon overburden. FIG. 3A schematically shows an example substrate 300 comprises gaps 302, 304. Substrate 300 further comprises a carbon film 306 deposited onto the substrate and within gaps 302, 304. Carbon film 306 is deposited using PECVD with a relatively higher power RF power for faster deposition. However, due to relatively higher power, the PECVD process results in top-heavy growth. As shown in FIG. 3 A, the carbon film 306 is thicker on field regions 310 than within the gaps 302, 304.

[0056] FIG. 3B schematically shows substrate 300 following further PECVD processing to fill gaps 302, 304 and form a carbon overburden 320 on the substrate. Due to faster film growth on field regions 310 of substrate 300, the carbon overburden grows thicker over the field regions than over the gaps 302, 304. This results information of dents 322, 324 in the carbon film 306 over gaps 302, 304, respectively. Dents can pose issues during further processing (e.g., a planarization step) of substrate 300.

[0057] As mentioned above, to avoid the issues of top-heavy deposition, feature-density-dependent differential film growth, and denting described above, PECVD gapfill processes can use RF power comprising a relatively lower power, such as a power of 450 W or lower.

[0058] However, PECVD gapfill processes that use relatively lower power are slow. This can decrease throughput and increase substrate processing cost. Accordingly, examples are disclosed that address the above issues. Briefly, a substrate comprising a gap is positioned in a processing chamber configured for PECVD. Then, a carbon-containing precursor is introduced into a processing chamber. A passivation agent and / or an etching agent also is introduced into the processing chamber. A plasma is formed using multifrequency RF power comprising two or more RF power components at a corresponding two or more different frequencies. The RF power comprises at least a first, lower-frequency RF power component and a second, higher- frequency RF power component. The lower-frequency RF power component comprises a frequency within a range of 400 kHz to 3 MHz. The higher-frequency RF power component comprises a frequency within a range of 3 MHz to 300 MHz.

[0059] The plasma helps to convert carbon-containing precursor into a carbon film in the gap. Inclusion of the passivation agent and / or an etching agent in the plasma gas mixture helps to slow film growth near the top of the gap.

[0060] The use of multifrequency RF power can help deposit a high quality carbon gapfill film and enable use of higher power for faster deposition than the use of a single RF frequency. For example, the addition of the lower-frequency RF power component helps increase formation of radicals in the plasma compared to examples that omit lower-frequency RF power component. This helps increase reactive chemical species in the plasma. Further, the addition of the lower-frequency RF power helps ions in the plasma etch the carbon film. This helps to increase ion-based etching rates on surfaces near the top of the gap. As such, a PECVD gapfill process that uses includes a lower-frequency RF power component and a higher-frequency RF power component can allow for the use of greater RF powers and increase film growth rates within the gap and increase etching rates near the top of the gap compared to the use of single frequency RF power. By controlling the etching aspect with the addition of the lower-frequency RF power, the PECVD process can avoid top-heavy growth. By avoiding top-heavy growth, the examples also can help avoid the issues described above (e.g., feature-density-dependent differential film growth and dent formation) while operating at a relatively higher power than other processes. In some examples, multifrequency RF power can comprise a power of 800 W to 2000 W, or greater. Use of higher power helps to increase the deposition rate of the carbon film. As such, the use of multifrequency RF power helps to meet gapfill specifications while providing a faster PECVD gapfill than processes that use lower power. Faster gapfill can help to increase throughput and lower cost.

[0061] In some examples, the plasma can be formed using a powered substrate support. Briefly, a capacitively coupled plasma (CCP) can be formed in a processing chamber using a pair of electrodes. The RF power can be supplied to a substrate support on which the substrate is positioned. Another electrode, such as a showerhead, can be configured as a grounded electrode for forming the CCP. Use of a powered substrate support helps attract ions towards the substrate. This can help to increase ion-based etching processes and avoid top-heavy growth conditions. By avoiding top-heavy growth, a powered substrate support also can enable use of higher power RF power to increase film growth rates. In other examples, the RF power can be supplied to the showerhead, and the substrate support can be grounded. In further examples, RF power can be used to form a multifrequency inductively coupled plasma (ICP).

[0062] While the examples below are discussed in the context of forming a multifrequency RF plasma comprising a first and second component of RF power, any suitable number (N > 2) of RF power components can be used.

[0063] FIG. 4 shows an example method 400 for performing PECVD to fill a gap with a carbon film using a multifrequency RF plasma. At 402, method 400 comprises flowing a carbon-containing precursor into a processing chamber. Any suitable carbon-containing precursor can be used. Examples can include alkanes having a general formula CnH2n+2 where n = 1 to 10 (such as methane, ethane, etc.), alkenes having a general formula CnEbn where n = 2 to 10 (such as ethylene, propylene, etc.), alkynes having a general formula CnH2n-2 where n = 2 to 10 (such as acetylene, propyne, etc.), cyclic hydrocarbons (including aromatics), and alkyl amines and other nitrogencontaining compounds, that are gas-phase under processing conditions. In someexamples, at 404, the carbon-containing precursor comprises one or more of acetylene, ethylene, or propylene.

[0064] The processing chamber is configured for performing PECVD. The processing chamber comprises a pair of electrodes for forming a capacitively coupled plasma in the processing chamber. Processing gases can be introduced into the processing chamber via a showerhead. Further, the showerhead can be configured as an electrode for forming a plasma. In some examples, at 406, method 400 comprises flowing the carbon-containing precursor through an electrically-grounded showerhead into the processing chamber. As described below, in other examples, RF power can be applied to the showerhead.

[0065] Continuing, at 408, method 400 comprises flowing one or more of a passivating agent or an etching agent into the processing chamber. Suitable passivating agents can include any gas that can chemisorb or physisorb to a surface of the substrate and reduce a rate of carbon film growth on the substrate in a PECVD carbon deposition process. By appropriately controlling conditions within the processing chamber, the substrate surface can be selectively passivated. Suitable etching agents can include any material that remove a material from a substrate as the material is deposited by PECVD. In some examples, the one or more of the passivating agent or the etching agent comprises one or more of molecular hydrogen (Eb), ammonia (NEE), carbon dioxide (CO2), carbon monoxide (CO), carbon oxysulfide (COS), molecular oxygen (O2), boron trifluoride (BF3), nitrogen trifluoride (NF3), sulfur dioxide (SO2), sulfur hexafluoride (SFe), a halocarbon gas, a halohydrocarbon gas, a halogen acid (hydrofluoric acid (HF), hydrochloric acid (HC1), hydrobromic acid (HBr), hydroiodic acid (HI)), fluorine (F2), chlorine (Ch), bromine (Bn), or iodine (I2).

[0066] In some examples, at 412, method 400 optionally comprises flowing an inert gas into the processing chamber. Any suitable inert gas or combination of inert gases can be used. Examples include one or more of helium (He), neon (Ne), argon (Ar), xenon (Xe), krypton (Kr), or molecular nitrogen (N2). An inert gas can be used to help deliver the carbon-containing precursor(s) and the one or more of the passivating agent(s) or the etching agent(s). The use of an inert gas in a PECVD process also can help formation ions and radicals in the RF plasma.

[0067] Method 400 further comprises, at 414, forming a radiofrequency (RF) plasma using RF power to convert the carbon-containing precursor into a carbon film in the gap. The RF power comprises a first, lower-frequency RF power and a second,higher-frequency RF power. The first RF power component comprises a frequency within a range of 400 kHz to 3 MHz. The second RF power component comprises a frequency within a range of 3 MHz to 300 MHz. Examples of suitable frequencies for the first, lower-frequency RF power component include 400 kHz, 430 kHz, 460 kHz, 490 kHz, 1 MHz, and 2 MHz. Examples of suitable frequencies for the second, higher- frequency RF power component include 13.56 MHz, 27 MHz, 60 MHz, and 90 MHz. In some examples, the RF power can further comprise one or more additional RF power components comprising one or more additional frequencies different from the first RF power component and the second RF power component.

[0068] The lower-frequency RF power drives formation of radicals in the plasma. This helps increase reactive chemical species in the plasma. Further, the lower- frequency RF power helps ions in the plasma etch the carbon film. This helps to increase ion-based etching rates on surfaces near the top of the gap and avoid top-heavy growth. By avoiding top-heavy growth, the use of multifrequency RF power allows for the use of relatively higher power for faster deposition without sacrificing film quality compared to the use of single frequency RF power. In some examples, at 416, the first RF power component comprises a power of 200 W to 500 W. In some examples, at 418, the second RF power component comprises a power of 100 W to 1000 W. In other examples, powers outside these ranges can be used.

[0069] In addition to RF plasma conditions, various processing chamber conditions also can be controlled at step 414. Examples can include one or more of a substrate temperature, a processing chamber pressure, a partial pressure of one or more processing gases of a gas mixture, and a flow rate of one or more processing gases of the gas mixture.

[0070] Further, any suitable substrate temperature can be used during a carbon film deposition process. In some examples, the substrate can be heated using a substrate heater temperature of 25 °C to 700 °C. In other examples, substrate heater temperatures outside of this range can be used. Relatively higher temperatures can favor deposition of carbon relatively deeper within a gap on the substrate. Relatively lower temperatures can favor greater vertical growth of deposited carbon.

[0071] In some examples, at 420, the RF power is supplied to a substrate support. In such examples, the showerhead can be configured at a grounded electrode, as mentioned above at step 406. Use of a powered substrate support helps attract ions towards the substrate to increase etching rates and thereby avoid top-heavy growth. Inother examples, RF power can be supplied to another electrode within the processing chamber, such as a showerhead.

[0072] Continuing, in some examples, at 422, method 400 comprises filling the gap with the carbon film without forming a dent in the carbon film above the gap. Avoiding dent formation can facilitate further substrate processes, such as planarization. In other examples, the carbon film can comprise a dent above the gap, depending upon deposition conditions used.

[0073] In some examples, at 424, the substrate comprises a first region comprising a plurality of gaps at a first feature density and a second region comprising a plurality of gaps at a second feature density different from the first feature density. In some examples, the substrate can comprise a region without gaps. In such examples, the use of multifrequency RF power to form the plasma at 414 helps to avoid feature- density-dependent differential film growth.

[0074] FIGS. 5A-5D schematically show example structures that can be formed using method 400. FIG. 5A shows a substrate 500 comprising gaps 502, 504. Substrate 500 can comprise any suitable material. Examples include silicon, silicon oxide, and silicon nitride. Gaps 502, 504 can comprise any suitable aspect ratio. Examples include aspect ratios of 5 : 1 to 60: 1.

[0075] FIG. 5B shows substrate 500 following PECVD processing to deposit a carbon film 506 onto substrate 500 and within gaps 502, 504. Carbon film 506 can comprise amorphous carbon, for example. Carbon film 506 is deposited using method 400. A carbon-containing precursor and one or more of a passivating agent and an etching agent are introduced to the processing chamber. A multifrequency RF plasma 508 is formed as described above at step 414 of method 400. The RF power used to form the multifrequency RF plasma 508 comprises a first, lower-frequency RF power component and a second, higher-frequency RF power. The first RF power component comprises a frequency within a range of 400 kHz to 3 MHz. The first, lower frequency RF power component can comprise any suitable power, such as a power within a range of 200 W to 500 W. The second, higher frequency component of RF power comprises a frequency within a range of 3 MHz to 300 MHz. The second, higher frequency RF power component can comprise any suitable power, such as a power within a range of 100 W to 1000 W. Using a lower-frequency RF power component and a higher- frequency RF power component to form a plasma helps increase ion-based etching on upper surfaces of carbon film 506. This helps avoid top-heavy growth of the carbonfilm 506. As a result, carbon film 506 grows with a v-shaped profile, allowing the entire gap to be filled. Further, the use of the lower-frequency RF power component and the higher-frequency RF power component allows the use of relatively higher RF powers. This can help to achieve faster deposition than the use of single frequency RF power at lower powers.

[0076] FIG. 5C shows substrate 500 following further PECVD processing. Due to the use of multifrequency RF plasma 508, the carbon film 506 is deposited without top-heavy growth and comprises a v-shaped profile. By avoiding top-heavy growth, the PECVD process also helps avoid feature-density-dependent differential film growth (e.g., FIG. 2) and dent formation (e.g., FIGS. 3A-3B).

[0077] FIG. 5D shows substrate 500 following further PECVD processing to fill gaps 502, 504. Carbon film 506 comprises a relatively planar surface without dents. Thus, by using a multifrequency RF plasma formed using a relatively higher power, the PECVD process can perform carbon gapfill faster than processes that use a single frequency RF plasma at relatively lower power. Further, in contrast to processes that use a single frequency RF plasma, the use of a multifrequency RF plasma can help to avoid top-heavy growth, and to mitigate feature-density-dependent differential film growth and dent formation.

[0078] FIG. 6 schematically shows an example structure formed using method 400 to avoid feature-density-dependent differential film growth. FIG. 6 shows a substrate 600 comprising gaps 602, 604 in a first region 606. Substrate 600 further comprises a field region 608 between gaps 602, 604. Substrate 600 further comprises gaps 612, 614 in a second region 616. Gap 612 is spaced apart from gap 614 with a relatively larger field region 618 therebetween. As such, the second region 616 of substrate 600 comprises a relatively lower feature density than first region 606.

[0079] Substrate 600 further comprises a carbon film 620 deposited using method 400. FIG. 6 shows substrate 600 in a partially filled state. Variations in film thickness on field regions 608, 618 can become more pronounced as carbon film 606 grows thicker. By performing PECVD using a multifrequency RF plasma, carbon film 506 is deposited without top-heavy growth. As such, the deposition of carbon film 620 is less affected by feature-density-dependent differential film growth as the example of FIG. 2. Further, by using a multifrequency RF plasma , the PECVD process can perform carbon gapfill faster using relatively higher powers than processes that use a single RF frequency plasma at relatively lower powers.

[0080] FIG. 7 schematically shows a processing tool 700 configured for performing plasma-enhanced chemical vapor deposition (PECVD). Processing tool 700 comprises a processing chamber 702 and a substrate support 704 within the processing chamber. The substrate support 704 is configured to support a substrate 706 disposed within processing chamber 702. The substrate support 704 comprises a substrate heater 708. In other examples, a heater can be omitted, or can be located elsewhere within processing chamber 702. The processing tool 700 further comprises a showerhead 710 for introducing processing chemicals into the processing chamber. In some examples, the processing tool 700 comprises a heater configured to heat showerhead 710.

[0081] The processing tool 700 further comprises flow control hardware 712. The flow control hardware 712 connects processing chemical source(s) to the processing chamber. In the depicted example, the flow control hardware 712 connects a carbon-containing film precursor source 716, a passivation agent source 718, an etching agent source 720, and an optional inert gas source 722 to the processing chamber. The flow control hardware 712 can include any suitable components. Examples include mass flow controllers, valves, and conduits. For example, the flow control hardware 712 can comprise one or more valves controllable to place a selected gas source or selected gas sources in fluid connection with showerhead 710. The flow control hardware 712 also can comprise one or more mass flow controllers or other controllers for controlling a mass flow rate of gas.

[0082] The carbon-containing precursor source 716 comprises any suitable precursor compound(s) for forming a carbon film. Examples of carbon-containing precursors include alkanes having a general formula CnH2n+2 where n is an integer in a range of 1 to 10 (such as, methane, ethane, etc.), alkenes having a general formula CnEEn where n = 2 to 10 (such as, ethylene, propylene, etc.), and alkynes having a general formula CnH2n-2 where n = 2 to 10 (such as, acetylene, propyne, etc.), that are gas-phase under processing conditions. Other examples of carbon-containing film precursors comprise cyclic hydrocarbons including aromatics, nitrogen-containing compounds including alkyl amines, and oxygen-containing compounds including alcohols, ketones, esters, aldehydes, and ethers that are gas-phase under processing conditions, alkanes, alkenes, alkynes, cyclic hydrocarbons, aromatics, alcohols, aldehydes, esters, ethers, ketones, aldehydes, alkyl halides, alkyl amines, and alkyl diamines.

[0083] The passivating agent source 718 comprises any suitable passivation agent. Suitable passivating agents can include any gas that can chemisorb or physisorbto a surface of the substrate and reduce a rate of carbon film growth on the substrate in a PECVD carbon deposition process. Suitable passivating agents can include one or more of molecular hydrogen (H2), ammonia (NH3), or sulfur dioxide (SO2).

[0084] The etching agent source 720 comprises any suitable etching agent. Suitable etching agents can include any material that remove a material from a substrate as the material is deposited by PECVD. Suitable etching agents can include one or more halogen-containing gases and / or one or more oxygen-containing gases. Example halogen-containing etching agents can include one or more of chlorine (Ch), fluorine (F2), bromine (Bn), iodine (I2), a halogen acid (hydrofluoric acid (HF), hydrochloric acid (HC1), hydrobromic acid (HBr), hydroiodic acid (HI)), nitrogen trifluoride (NF3), boron trifluoride (BF3), sulfur hexafluoride (SFe), a halocarbon gas, or a halohydrocarbon gas. Example oxygen-containing etching agents can include one or more of carbon monoxide (CO), carbon dioxide (CO2), carbon oxy sulfide (COS), sulfur dioxide (SO2), or molecular oxygen (O2). In other examples, one of passivation agent source 718 or etching agent source 720 can be omitted.

[0085] The optional inert gas source 722 comprises any suitable inert gas. Examples include argon, helium, neon, krypton, xenon, molecular nitrogen, or a combination thereof.

[0086] The processing tool 700 further comprises an exhaust system 732. The exhaust system 732 is configured to exhaust gases from the processing chamber 702. The exhaust system 732 can comprise any suitable hardware, including one or more low vacuum pumps, one or more high vacuum pumps, and one or more valves for controlling an exhaust flow. Together, flow control hardware 712 and exhaust system 732 can be operated to achieve a selected pressure in processing chamber 702 during substrate processing. Example pressures include pressures of 1 Torr to 20 Torr. Further, exhaust system 732 can be operated to purge processing chamber 702.

[0087] The processing tool 700 further comprises an RF power source 734 configured to form a RF plasma in processing chamber 702 using a gas mixture. The RF power source 734 can supply RF power to the showerhead electrode or substrate holder electrode in various examples. As shown in FIG. 7, the RF power is provided to substrate support 704, and showerhead 710 is configured as a grounded opposing electrode. As mentioned above, use of a powered substrate support helps attract ions towards the substrate to increase etching rates and avoid top-heavy growth. In other examples, the RF power source 734 can supply RF power to showerhead 710, andsubstrate support 704 can be grounded. In the depicted example, a capacitively coupled plasma can be formed in processing chamber 702 between showerhead 710 and substrate support 704. In other examples, an inductively coupled plasma can be used.

[0088] The processing tool 700 further includes a matching network 736 for impedance matching of the RF power source 734. The radiofrequency power source 734 is configured to provide RF power comprising a lower-frequency (LF) RF power 734A and a higher-frequency (HF) RF power 734B. Example frequencies for the lower- frequency RF power include frequencies of 40 kHz to 3 MHz. Examples frequencies for the higher-frequency RF power include frequencies of 3 MHz to 300 MHz. The lower-frequency RF power can comprise a power of 200 to 500 W, in some examples. Further, the higher-frequency RF power can comprise a power of 100 W to 1000 W, in some examples.

[0089] The processing tool 700 further comprises a controller 750 configured to control operation of the processing tool. The controller 750 is operatively coupled to the substrate heater 708, the flow control hardware 712, the exhaust system 732, and the RF power source 734. The controller 750 is configured to control various functions of processing tool 700 to perform PECVD. For example, the controller 750 is configured to control processing tool 700 to operate the substrate heater 708 to heat to a desired temperature. Examples include temperatures of 25 °C to 700 °C. The controller 750 also is configured to operate the flow control hardware 712 to flow a selected gas or mixture of gases at a selected rate into the processing chamber 702. The controller 750 is further configured to operate the exhaust system 732 to remove gases from processing chamber 702. The controller 750 can, for example, control the exhaust system 732 and / or the flow control hardware 712 to purge the processing chamber 702. The controller 750 is configured to operate the RF power source 734 to form a multifrequency RF plasma, as well as to control any other suitable functions of processing tool 700.

[0090] Controller 750 can comprise any suitable computing system. FIG. 8 schematically shows a non-limiting example of a computing system 800 that can enact one or more of the methods and processes described above. Computing system 800 is shown in simplified form. Computing system 800 can take the form of one or more personal computers, workstations, computers integrated with substrate processing tools, and / or network accessible server computers.

[0091] Computing system 800 includes a logic subsystem 802 and a storage subsystem 804. Computing system 800 can optionally include a display subsystem 806, input subsystem 808, communication subsystem 810, and / or other components not shown in FIG. 8. Controller 750 is an example of computing system 800.

[0092] Logic subsystem 802 includes one or more physical devices configured to execute instructions. For example, the logic machine can be configured to execute instructions that are part of one or more applications, services, programs, routines, libraries, objects, components, data structures, or other logical constructs. Such instructions can be implemented to perform a task, implement a data type, transform the state of one or more components, achieve a technical effect, or otherwise arrive at a desired result.

[0093] The logic machine can include one or more processors configured to execute software instructions. Additionally or alternatively, the logic machine can include one or more hardware or firmware logic machines configured to execute hardware or firmware instructions. Processors of the logic machine can be single-core or multi-core, and the instructions executed thereon can be configured for sequential, parallel, and / or distributed processing. Individual components of the logic machine optionally can be distributed among two or more separate devices, which can be remotely located and / or configured for coordinated processing. Aspects of the logic machine can be virtualized and executed by remotely accessible, networked computing devices configured in a cloud-computing configuration.

[0094] Storage subsystem 804 includes one or more physical devices configured to hold instructions 812 executable by the logic machine to implement the methods and processes described herein. When such methods and processes are implemented, the state of storage subsystem 804 can be transformed — e.g., to hold different data.

[0095] Storage subsystem 804 can include removable and / or built-in devices. Storage subsystem 804 can include optical memory (e.g., CD, DVD, HD-DVD, Blu- Ray Disc, etc.), semiconductor memory (e.g., RAM, EPROM, EEPROM, etc.), and / or magnetic memory (e.g., hard-disk drive, floppy-disk drive, tape drive, MRAM, etc.), among others. Storage subsystem 804 can include volatile, nonvolatile, dynamic, static, read / write, read-only, random-access, sequential-access, location-addressable, file- addressable, and / or content-addressable devices.

[0096] It will be appreciated that storage subsystem 804 includes one or more physical devices. However, aspects of the instructions described herein alternatively can be propagated by a communication medium (e.g., an electromagnetic signal, an optical signal, etc.) that is not held by a physical device for a finite duration.

[0097] Aspects of logic subsystem 802 and storage subsystem 804 can be integrated together into one or more hardware-logic components. Such hardware-logic components can include field-programmable gate arrays (FPGAs), program- and application-specific integrated circuits (PASIC / ASICs), program- and applicationspecific standard products (PSSP / ASSPs), system-on-a-chip (SOC), and complex programmable logic devices (CPLDs), for example.

[0098] When included, display subsystem 806 can be used to present a visual representation of data held by storage subsystem 804. This visual representation can take the form of a graphical user interface (GUI). As the herein described methods and processes change the data held by the storage machine, and thus transform the state of the storage machine, the state of display subsystem 806 can likewise be transformed to visually represent changes in the underlying data. Display subsystem 806 can include one or more display devices utilizing virtually any type of technology. Such display devices can be combined with logic subsystem 802 and / or storage subsystem 804 in a shared enclosure, or such display devices can be peripheral display devices.

[0099] When included, input subsystem 808 can comprise or interface with one or more user-input devices such as a keyboard, mouse, or touch screen. In some examples, the input subsystem can comprise or interface with selected natural user input (NUI) componentry. Such componentry can be integrated or peripheral, and the transduction and / or processing of input actions can be handled on- or off-board. Example NUI componentry can include a microphone for speech and / or voice recognition, and an infrared, color, stereoscopic, and / or depth camera for machine vision and / or gesture recognition.

[0100] When included, communication subsystem 810 can be configured to communicatively couple computing system 800 with one or more other computing devices. Communication subsystem 810 can include wired and / or wireless communication devices compatible with one or more different communication protocols. As non-limiting examples, the communication subsystem can be configured for communication via a wireless telephone network, or a wired or wireless local- or wide-area network. In some examples, the communication subsystem can allowcomputing system 800 to send and / or receive messages to and / or from other devices via a network such as the Internet.

[0101] It will be understood that the configurations and / or approaches described herein are exemplary in nature, and that these specific examples or examples are not to be considered in a limiting sense, because numerous variations are possible. The specific routines or methods described herein can represent one or more of any number of processing strategies. As such, various acts illustrated and / or described can be performed in the sequence illustrated and / or described, in other sequences, in parallel, or omitted. Likewise, the order of the above-described processes can be changed.

[0102] The subject matter of the present disclosure includes all novel and non- obvious combinations and sub-combinations of the various processes, systems and configurations, and other features, functions, acts, and / or properties disclosed herein, as well as any and all equivalents thereof.

Claims

CLAIMS:

1. A method of filling a gap on a substrate disposed in a processing chamber, the method comprising: flowing a carbon-containing precursor into the processing chamber; flowing one or more of a passivation agent or an etching agent into the processing chamber; and forming a radiofrequency (RF) plasma using RF power to convert the carbon- containing precursor into a carbon film in the gap, the RF power comprising a first RF power component and a second RF power component, the first RF power component comprising a frequency within a range of 400 kHz to 3 MHz and the second RF power component comprising a frequency within a range of 3 MHz to 300 MHz.

2. The method of claim 1, wherein the second RF power component comprises a power of 100 W to 1000 W.

3. The method of claim 1, wherein the first RF power component comprises a power of 200 W to 500 W.

4. The method of claim 1, wherein the carbon-containing precursor comprises one or more of acetylene, ethylene, or propylene.

5. The method of claim 1, wherein the one or more of the passivating agent or the etching agent comprises one or more of molecular hydrogen (H2), ammonia (NH3), carbon dioxide (CO2), carbon monoxide (CO), carbon oxysulfide (COS), molecular oxygen (O2), boron trifluoride (BF3), nitrogen trifluoride (NF3), sulfur dioxide (SO2), sulfur hexafluoride (SFe), a halocarbon gas, a halohydrocarbon gas, a halogen acid (hydrofluoric acid (HF), hydrochloric acid (HC1), hydrobromic acid (HBr), hydroiodic acid (HI)), fluorine (F2), chlorine (Ch), bromine (Bn), or iodine (I2).

6. The method of claim 1, further comprising flowing an inert gas into the processing chamber.

7. The method of claim 1, wherein the carbon-containing precursor is flowed into the processing chamber through an electrically grounded showerhead, and the RF power is supplied to a substrate support in the processing chamber.

8. The method of claim 1, wherein the substrate comprises a first region comprising a plurality of gaps at a first feature density and a second region comprising a plurality of gaps at a second feature density different from the first feature density.

9. A processing tool for depositing a carbon film onto a substrate, the substrate comprising a gap, the processing tool comprising: a processing chamber; a substrate support; flow control hardware configured to control processing chemical flow into the processing chamber; a radiofrequency (RF) power source configured to provide RF power to form a plasma in the processing chamber; and a controller operatively coupled to the flow control hardware, and the RF power source, the controller being configured to operate the flow control hardware to flow a carbon-containing precursor into the processing chamber, operate the flow control hardware to flow one or more of an etching agent or a passivation agent into the processing chamber, and operate the RF power source to supply RF power to an electrode in the processing chamber, thereby forming a plasma to convert the carbon-containing precursor into a carbon film in the gap, the RF power comprising a first RF power and a second RF power, the first RF power component comprising a frequency within a range of 400 kHz to 3 MHz and the second RF power component comprising a frequency within a range of 3 MHz to 300 MHz.

10. The processing tool of claim 9, wherein the second RF power component comprises a power of 100 W to 1000 W.

11. The processing tool of claim 9, wherein the first RF power component comprises a power of 200 W to 500 W.

12. The processing tool of claim 9, further comprising a carbon-containing precursor source comprising one or more of acetylene, ethylene, or propylene.

13. The processing tool of claim 9, further comprising one or more of a passivating agent source or an etching agent source, the one or more of the passivating agent source or the etching agent source comprising one or more of molecular hydrogen (H2), ammonia (NH3), carbon dioxide (CO2), carbon monoxide (CO), carbon oxysulfide (COS), molecular oxygen (O2), boron trifluoride (BF3), nitrogen trifluoride (NF3), sulfur dioxide (SO2), sulfur hexafluoride (SFe), a halocarbon gas, a halohydrocarbon gas, a halogen acid (hydrofluoric acid (HF), hydrochloric acid (HC1), hydrobromic acid (HBr), hydroiodic acid (HI)), fluorine (F2), chlorine (Ch), bromine (Bn), or iodine (I2).

14. The processing tool of claim 9, wherein the controller is further configured to operate the flow control hardware to flow an inert gas into the processing chamber.

15. The processing tool of claim 9, further comprising an electrically grounded showerhead for flowing gases into the processing chamber, and wherein the RF power source is electrically connected to the substrate support.

16. A processing tool for depositing a carbon film onto a substrate, the substrate comprising a gap, the processing tool comprising: a processing chamber; a substrate support comprising a first electrode; a showerhead configured for introducing processing chemicals into the processing chamber, the showerhead comprising a second electrode configured as an electric ground; flow control hardware configured to control processing chemical flow through the showerhead into the processing chamber; a radiofrequency (RF) power source electrically connected to the substrate support, the RF power source configured to form a plasma in the processing chamber; and a controller operatively coupled to the flow control hardware, and the RF power source, the controller being configured tooperate the flow control hardware to flow a carbon-containing precursor into the processing chamber, operate the flow control hardware to flow one or more of an etching agent or a passivation agent into the processing chamber, and operate the RF power source to supply RF power to an electrode in the processing chamber, thereby forming a plasma to convert the carbon-containing precursor into a carbon film in the gap, the RF power comprising a first RF power component and a second RF power component, the first RF power component comprising a frequency within a range of 400 kHz to 3 MHz and the second RF power component comprising a frequency within a range of 3 MHz to 300 MHz.

17. The processing tool of claim 16, wherein the second RF power component comprises a power of 100 W to 1000 W.

18. The processing tool of claim 16, wherein the first RF power component comprises a power of 200 W to 500 W.

19. The processing tool of claim 16, further comprising a carbon-containing precursor source comprising one or more of acetylene, ethylene, or propylene.

20. The processing tool of claim 16, further comprising one or more of a passivating agent source or an etching agent source, the one or more of the passivating agent source or the etching agent source comprising one or more of molecular hydrogen (H2), ammonia (NH3), carbon dioxide (CO2), carbon monoxide (CO), carbon oxysulfide (COS), molecular oxygen (O2), boron trifluoride (BF3), nitrogen trifluoride (NF3), sulfur dioxide (SO2), sulfur hexafluoride (SFe), a halocarbon gas, a halohydrocarbon gas, a halogen acid (hydrofluoric acid (HF), hydrochloric acid (HC1), hydrobromic acid (HBr), hydroiodic acid (HI)), fluorine (F2), chlorine (Ch), bromine (Bn), or iodine (I2).

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