Temporal switching to achieve geometric selective deposition of carbon in patterned features

Abstract

Examples are disclosed that relate to depositing carbon films using a pulsed plasma. One example provides a processing tool, comprising a processing chamber, a substrate holder, a showerhead, flow control hardware configured to connect one or more processing gas sources with the showerhead, a radiofrequency (RF) power supply configured to provide RF power to form a plasma between the substrate holder and the showerhead, and a controller configured to control the flow control hardware to introduce a flow of a carbon-containing precursor and an etchant into the processing chamber through the showerhead during a deposition process, and to control the RF power supply to pulse the plasma during the deposition process.

Description

TEMPORAL SWITCHING TO ACHIEVE GEOMETRIC SELECTIVE DEPOSITION OF CARBON IN PATTERNED FEATURESBACKGROUND

[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. PECVD 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] One example provides a processing tool. The processing tool comprises a processing chamber, a substrate holder, a showerhead, flow control hardware configured to connect one or more processing gas sources with the showerhead, a radiofrequency (RF) power supply configured to provide RF power to form a plasma between the substrate holder and the showerhead, and a controller. The controller is configured to control the flow control hardware to introduce a flow of a carbon- containing precursor and an etchant into the processing chamber through the showerhead during a deposition process, and to control the RF power supply to pulse the plasma during the deposition process.

[0004] In some such examples, the RF power supply is configured to supply a lower frequency (LF) RF power and a higher frequency (HF) RF power to form a multifrequency plasma during the deposition process.

[0005] Alternatively or additionally, in some such examples, the controller is configured to control the RF power supply to pulse the LF RF power while providing continuous wave HF RF power during the deposition process.

[0006] Alternatively or additionally, in some such examples, the controller is configured to control the RF power supply to pulse the HF RF power while providing continuous wave LF RF power during the deposition process.

[0007] Alternatively or additionally, in some such examples, the controller is configured to control the RF power supply to pulse the HF RF power and to pulse the LF RF power during the deposition process.

[0008] Alternatively or additionally, in some such examples, the RF power supply is configured to provide a single frequency of RF power.

[0009] Alternatively or additionally, in some such examples, the etchant comprises one or more of hydrogen (H2), ammonia (NH3), hydrazine (N2H4), chlorine (Ch), fluorine (F2), bromine (Bn), iodine (I2), hydrofluoric acid (HF), hydrochloric acid (HC1), hydrobromic acid (HBr), hydroiodic acid (HI), nitrogen trifluoride (NF3), boron trifluoride (BF3), sulfur hexafluoride (SFe), a halocarbon gas having a general formula CaXb (where X comprises one or more of fluorine, chlorine, bromine, or iodine and where a = 1-10), a halohydrocarbon gas having a general formula CaHbXc (where X comprises one or more of fluorine, chlorine, bromine, or iodine and where a = 1-10), carbon monoxide (CO), carbon dioxide (CO2), carbon oxysulfide (COS), sulfur dioxide (SO2), or molecular oxygen (O2).

[0010] Alternatively or additionally, in some such examples, the carbon- containing precursor comprises one or more of an alkane having a general formula CnH2n+2 where n is an integer in a range of 1 to 10, an alkene having a general formula CnH2n where n = 2 to 10, an alkyne having a general formula CnH2n-2 where n = 2 to 10, an aromatic hydrocarbon, an aliphatic cyclic hydrocarbon, or an alkyl amine.

[0011] Alternatively or additionally, in some such examples, a ratio of etchant: carbon-containing precursor in the flow into the processing chamber is of 2: 1 to 30: 1.

[0012] Alternatively or additionally, in some such examples, a pulse frequency of the pulsed plasma is within a range of 2 hertz to 10 kilohertz.

[0013] Alternatively or additionally, in some such examples, a duty cycle of the pulsed plasma is within a range of 10 - 90%.

[0014] Alternatively or additionally, in some such examples, the controller is configured to adjust a ratio of the carbon-containing precursor and the etchant after a period of carbon film deposition to cause a net etching of the carbon film.

[0015] Another example provides a method, comprising introducing a flow of a carbon-containing precursor and an etchant into a processing chamber during a deposition process. The method further comprises controlling a radiofrequency (RF) power supply to pulse a plasma in the processing chamber during the deposition process.

[0016] In some such examples, controlling the RF power supply comprises controlling the RF power supply to supply a lower frequency (LF) RF power and a higher frequency (HF) RF power to form a multi-frequency plasma during the deposition process.

[0017] Alternatively or additionally, in some such examples, controlling the RF power supply to pulse the plasma comprises controlling the RF power supply to pulse the LF RF power while providing continuous wave HF RF power during the deposition process.

[0018] Alternatively or additionally, in some such examples, controlling the RF power supply to pulse the plasma comprises controlling the RF power supply to pulse the the HF RF power while providing continuous wave LF RF power during the deposition process.

[0019] Alternatively or additionally, in some such examples, controlling the RF power supply to pulse the plasma comprises controlling the RF power supply to pulse the HF RF power and to pulse the LF RF power during the deposition process.

[0020] Alternatively or additionally, in some such examples, controlling the RF power supply comprises controlling the RF power supply to provide a single frequency of RF power during the deposition process.

[0021] Alternatively or additionally, in some such examples, introducing the flow of the carbon-containing precursor and the etchant into the processing chamber comprises flowing a ratio of etchant: carbon-containing precursor of 2: 1 to 30: 1 into the processing chamber.

[0022] Alternatively or additionally, in some such examples, the method further comprises adjusting a ratio of the carbon-containing precursor and the etchant after a period of carbon film deposition to cause a net etching of the carbon film.

[0023] Another example provides a method for carbon gapfill. The method comprises flowing a carbon-containing precursor and an etchant into a processing chamber. The method further comprises controlling a radiofrequency (RF) power supply to form a plasma in the processing chamber, thereby depositing a carbon film in a gap on a substrate disposed in the processing chamber, the carbon film being substantially void-free. The method further comprises, while depositing the carbon film, controlling the RF power supply to pulse the plasma so that the deposited carbon film comprises a modulus of elasticity within a range of 25 to 80 GPa.

[0024] In some such examples, controlling the RF power supply comprises controlling the RF power supply to supply a lower frequency (LF) RF power and a higher frequency (HF) RF power to form a multi-frequency plasma during the deposition process.

[0025] Alternatively or additionally, in some such examples, controlling the RF power supply to pulse the plasma comprises controlling the RF power supply to pulse the LF RF power while providing continuous wave HF RF power during the deposition process.

[0026] Alternatively or additionally, in some such examples, the deposited carbon film comprises a density within a range of 1.2 to 1.7 g / cm3.BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 schematically shows examples of structures that can be formed in an amorphous carbon plasma enhanced chemical vapor deposition (PECVD) process.

[0028] FIGS. 2A-2C schematically show structures formed in a first cyclic deposition / etch process for performing carbon gapfill.

[0029] FIGS. 3A-3D schematically show structures formed in a second cyclic deposition / etch process for performing carbon gapfill.

[0030] FIGS. 4A-D schematically show structures formed in an example pulsed plasma carbon deposition process for performing carbon gapfill.

[0031] FIGS. 5A-5C schematically show structures formed in a top-heavy etching process performed on a gapfill film deposited using the method of FIGS. 4A- 4D.

[0032] FIG. 6 shows a flow diagram of an example method for depositing a carbon film on a substrate.

[0033] FIG. 7 shows a schematic depiction of an example processing tool.

[0034] FIG. 8 shows a block diagram of an example computing device.DETAILED DESCRIPTION

[0035] The term “carbon-containing precursor” generally represents any material that can be introduced into a processing chamber in a gas phase to form an amorphous carbon film on a substrate. 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 aromatic hydrocarbons, cyclic aliphatic hydrocarbons, heterocyclic compounds, and alkyl amines and other nitrogen-containing compounds, that are gas-phase under processing conditions and that include carbon-containing functional groups.

[0036] 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 processing 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.

[0037] The term "etchant" generally represents any material used in a PECVD processing gas mixture to remove materials from a substrate. Example etchants include hydrogen (H2), other hydrogen-containing gases (e.g. ammonia (NH3), hydrazine (N2H4)) halogen-containing gases, and oxygen-containing gases. Example halogencontaining etchants 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 oxygen-containing etchants include carbon monoxide (CO), carbon dioxide (CO2), carbon oxysulfide (COS), sulfur dioxide (SO2), and molecular oxygen (O2).

[0038] The term “flow control hardware” generally represents components configured to place one or more chemical sources in fluid connection with a processing chamber. Flow control hardware can comprise one or more mass flow controllers, valves, and various conduits, for example. Example chemical sources include film precursor sources, purge gas sources, and reactant gas sources.

[0039] The term “plasma” generally represents an ionized gas comprising gasphase cations and free electrons.

[0040] 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.

[0041] The term “processing tool” generally represents a machine including a processing chamber and other hardware configured to enable processing to be carried out in the processing chamber.

[0042] The term “pulse” and variants thereof generally represent temporal switching of a signal to cause modulation of an amplitude. For example, a pulsed plasma is a plasma that is formed using radiofrequency (RF) power with a power that is modulated at a lower frequency than the RF frequency. A higher power of a pulsed plasma cycle can be referred to as an “on” portion of the cycle, and a lower power of a pulsed plasma cycle can be referred to as an “off’ portion of the cycle, even if the RF power of the pulsed frequency is not fully cut to zero during the “off’ portion of the cycle. The term “continuous wave” is used to refer to RF power that is not pulsed during a deposition process, but rather is maintained at a set power level.

[0043] The term “showerhead” generally represents a processing chemical outlet comprising a plurality of holes distributed across an area.

[0044] The term “substrate” generally represents any object on which a film can be deposited.

[0045] The term “3D NAND” is an abbreviation of three-dimensional NOT AND, and generally represents memory architecture based upon NOT AND logic gates.

[0046] The term “3D NOR” is an abbreviation of three-dimensional NOT OR, and generally represents memory architecture based upon NOT OR logic gates.

[0047] The term “3D DRAM” is an abbreviation of three-dimensional dynamic random access memory.

[0048] As described above, the fabrication of electronic devices involves many steps of material deposition, patterning, and removal to form integrated circuits, such as logic and / or memory circuits, on substrates. Some steps can involve the deposition of amorphous carbon films to fill gaps in a substrate. A gap is a feature that has a recessed topology compared to adjacent substrate surfaces.

[0049] Amorphous carbon, hereinafter referred to as carbon, can be used as a gapfill material, for example, to protect sidewalls and / or other surfaces within a feature from damage caused by a subsequent etching process. Amorphous carbon can be deposited using plasma enhanced chemical vapor deposition (PECVD).

[0050] However, performing carbon gapfill processes using PECVD can pose various challenges. FIG. 1 illustrates an example substrate 100 comprising a carbon film 102 that illustrates some of the difficulties that can be encountered when performing gapfill using amorphous carbon. As one example, it can be challenging to deposit a carbon film with a desired degree of planarity when performing carbon gapfill over a substrate with a varied topography. As a more specific example, a substrate surface can have gaps of different depths and / or widths. When filling such gaps with carbon, the resulting carbon film can have height differences at its surface that arise from the underlying substrate topology. Referring to FIG. 1, one example of nonplanarity is illustrated as a prominence 104 (also indicated by the number “1” in FIG. 1) formed over a substrate surface 105 that is located between gaps 106, 108. Another example of non-planarity is illustrated as dishing 110 in carbon film 102 over gap 108. Such dishing and prominences impact a planarity of a carbon film surface, which can impact downstream substrate processing.

[0051] Another challenge that can be encountered when performing carbon gapfill is the formation of voids. Carbon can tend to deposit preferentially within shallower regions of a gap, which can pinch off the gap prior to complete gapfill, thereby forming a void. Such voids can pose issues, for example, when using a carbon film as an etch stop layer. This is for at least the reason that a subsequent etching process can break through a carbon etch stop layer at a void, possibly causing damage to substrate surfaces within the gap. FIG. 1 illustrates an example void 112 formed within gap 114.

[0052] In addition to difficulties with planarity and / or voids, challenges also can arise with respect to the physical properties of a deposited carbon film. As one example, it may be desired to deposit a carbon film with a relatively higher modulus of elasticity (hereinafter “modulus”), such as 25 gigapascals (GPa) or higher. To form such a carbon film, a plasma-enhanced chemical vapor deposition (PECVD) process that utilizes a plasma with a higher frequency (HF) radiofrequency (RF) power component and a lower frequency (LF) RF power component can be used. The HF RF power component can comprise a frequency of 3 megahertz (MHz) or higher. The LF RF power component can comprise a frequency below 3 MHz. An example HF RF frequency is 13.56 MHz. An example LF RF frequency is 400 kilohertz (kHz).

[0053] However, the use of a plasma with an LF component to form a relatively higher modulus film can result in poor gapfill, with the formation of voids. Omitting the LF component to try to achieve better gapfill performance and avoid void formation can result in poor throughput, and also a relatively lower modulus film.

[0054] Further, and referring again to FIG. 1, structural damage to a substrate and / or a carbon film can result from some carbon deposition processes, such as processes that utilize LF RF power (due to sputter-related damage caused by ion impacts). An example of such damage is shown by rounded edge 116 where surface 105 meets gap 108. It may be desired to maintain sharp edges at a gap opening, as illustrated by edge 118 adj acent to gap 106. However, ion bombardment resulting from the use of an LF RF component can sputter such edges, resulting in a more rounded profile at the edges. Further, the carbon film 102 itself can be damaged during deposition.

[0055] In view of these and other challenges, processes for performing carbon gapfill on generally are separately designed for specific different topologies. Designing a carbon gapfill process to achieve a desired carbon film can be difficult and timeconsuming. Further, due to these complexities, a carbon gapfill process to achieve a desired combination of planarity, void presence / absence, modulus, and / or other physical properties can take multiple steps, and can involve tradeoffs between physical properties due to process limitations. FIGS. 2A-C and 3 A-D illustrate structures formed during two such multi-steps processes. As described below, the processes of FIGS. 2A- C and 3 A-D pose various drawbacks.

[0056] FIGS. 2A-2C show carbon film structures formed in a multi-step approach that involves cyclic deposition and etching processes. First, FIG. 2A showsa substrate 200 comprising a carbon film 202 after a first PECVD carbon deposition cycle. As can be seen, carbon film 202 has deposited relatively conformally on substrate surfaces of different orientations and heights relative to a substrate top surface, including surfaces within gaps 204, 206. Such conformal deposition can be achieved, for example, by utilizing a relatively lower power HF RF plasma in which carbon- containing radical species generated can diffuse to different substrate surfaces (e.g. as opposed to ions formed in the plasma, which deposit more directionally). Next, FIG. 2B shows carbon film 202 after a top-heavy etching step. The term “top-heavy” indicates that processing conditions favor etching of carbon film 202 from locations on the top surface of substrate 200 and less deep within gaps 204, 206. In various examples, hydrogen-based etches (e.g. utilizing hydrogen gas or and / or ammonia gas) or oxygenbased etches (e.g. using oxygen gas) can be used. The top-heavy etching step leaves portions of carbon film 202 deeper within gaps 204, 206, while removing other portions of carbon film 202. Additional cycles of deposition and top-heavy etching steps can be performed to result in a void-free filling of gaps 204, 206. A greater number of cycles may be needed to fill higher aspect ratio gaps.

[0057] However, carbon films formed according to the method of FIGS. 2A-2C can have a relatively low modulus (e.g. approximately 10 GPa). Further, the cyclic HF RF deposition / top-heaving etching process can have relatively low throughput. Additionally, where a substrate includes a relatively wide gap (e.g. such as gap 108 of FIG. 1), dishing can occur, thereby impacting a planarity of such carbon films.

[0058] FIGS. 3A-3D show a second multi-step approach that involves cyclic deposition and etching processes to form a carbon film 302 on a substrate 300. Instead of conformal deposition steps, the method illustrated in FIGS. 3A-3D utilizes a directional deposition process including a relatively high concentration of an etchant (e.g. hydrogen or carbon dioxide in some examples), and an LF RF plasma component. This process directionally deposits carbon at a higher rate on the substrate surfaces and bottom surfaces of gaps. This can be seen in FIG. 3 A, where a carbon film partially fills gaps 304, 306, and also deposits on substrate surfaces 308, 310, 312. The LF RF component of the plasma the drives directional ion-based deposition on the substrate surfaces. The etchant etches the carbon film as it deposits. Carbon deposited on surfaces with higher growth rates (e.g. substrate surfaces 308, 310, 312 and surfaces at the bottom of gaps 304, 306) undergoes net growth, while carbon deposited on surfaces with lower growth rates (e.g. sidewalls of gaps 304, 306, such as sidewall 316)undergoes net etching. This allows carbon film 302 to fill gaps 304, 306 without pinching off and forming a void. The etching also forms the tapered carbon film profiles on substrate surfaces 308, 310, 312.

[0059] Next referring to FIG. 3B, the deposition continues until an overburden of carbon is formed on substrate 300. As can be seen, the overburden of carbon has non-planarity due to the varying topology of substrate 300. Thus, and next referring to FIG. 3C, the carbon film is etched back to a level somewhat below the substrate surfaces 308, 310, 312. Then, additional carbon is deposited to form a planar film 302, as shown in FIG. 3D. However, like the process of FIGS. 2A-2C, the process of FIGS. 3A-3D tends to form a relatively lower modulus film (again, on the order of 10 GPa). Further, the carbon film can have varying density. For example, the carbon film above the gaps 304, 306 can be more dense than the carbon film within the gaps 304, 306.

[0060] Accordingly, examples are disclosed that relate to systems and methods for performing carbon gapfill that help to address the above-described difficulties with current multi-step processes. Briefly, the disclosed systems and methods utilize temporal switching of one or more frequency components of an RF plasma to achieve geometric selective deposition of carbon in patterned features. As one example, a carbon gapfill process can be performed in which continuous wave HF RF power and pulsed LF RF power are used to form a plasma. Further, both a carbon-containing precursor and an etchant are supplied to the plasma. A relatively higher proportion etchant to carbon-containing precursor is supplied compared to the multi-step methods described above. During the LF RF “off’ stage of the pulsed plasma cycle, etching may predominate, resulting in net material removal. During the LF RF “on” stage of the pulsed plasma cycle, the LF RF power may lead to net deposition of carbon by impinging the substrate surface with ionic species containing carbon. A pulsed plasma carbon deposition process can result in void-free gapfill with improved planarity compared to prior deposition methods without performing deposit! on / etching cycles. This can result in increased throughput relative to cyclic deposition / etching processes.

[0061] Further, the use of an LF RF power component in a pulsed plasma carbon deposition process can result in a higher modulus carbon film than a carbon film formed using cyclic deposition / etching methods. For example, the use of a plasma with a continuous wave HF RF component and a pulsed LF component can produce a carbon film with a modulus within a range of 25-80 GPa, and potentially higher. In comparison, cyclic deposition / etching processes can produce carbon films having a modulus of onthe order of 10-25 GPa. Further, the disclosed examples can fill a substrate having gaps of varying size while forming a more planar surface than prior deposition methods, avoiding both dishing and prominence formation.

[0062] As such, the disclosed deposition carbon gapfill processes and films are self-planarizing, high-modulus and high-density, and are able to fill varying critical dimension and varying high-aspect ratio structures in a void-free fashion without necessitating the design of highly customized processes for different substrate topologies. The disclosed examples can be used in a variety of different integrated circuit fabrication processes. Examples include logic circuit applications (FEOL (front end of line), MEOL (middle EOL) and BEOL (back EOL)), and memory applications (e.g. 3DNAND, DRAM and 3D-DRAM applications). While described herein primarily in the context of the use of a plasma formed by continuous wave HF RF power and pulsed LF RF power, a pulsed plasma carbon deposition process according to the present disclosure also can pulse HF RF power and use continuous wave LF RF power. In further examples, a pulsed plasma carbon deposition process can pulse both HF RF power and LF RF power. In yet further examples, a pulsed plasma carbon deposition process can use only pulsed HF RF power, with no LF component.

[0063] FIGS. 4A-4D schematically illustrate an example of carbon gapfill film deposited using a pulsed plasma according to the present disclosure. In this example, continuous wave HF RF power and pulsed LF RF power are used. In other examples, other pulsed plasma schemes can be used, as described above. FIG. 4A shows a carbon film 402 on a substrate 400 after a first duration of continuous wave HF RF and pulsed LF RF carbon deposition. As mentioned above, the gas mixture comprises a carbon- containing precursor and an etchant. Example precursors and etchants are described below. The mixture of the carbon-containing precursor and etchant, combined with the pulsed plasma, may cause net etching of the carbon film 402 when the LF RF is in an off state, and net deposition when the LF RF is in an on state. Further, the LF RF provides for more directional carbon film growth, rather than conformal growth, due to ion-based film growth occurring during the LF RF “on” pulse. Such direction growth is facilitated by use of a deposition tool in which RF power is provided to the substrate holder, rather than where RF power is provided to the showerhead, as the RF power applied to the substrate holder can be configured to accelerate ions in the plasma toward the substrate. Also, some sputtering and deposition can occur during the LF RF on pulses. As a result, the carbon film 402 grows at a higher rate on the bottom surfacewithin gap 406 and in field regions 408, 410 adjacent to gap 406, and at a lower rate on sidewalls 412 within the gaps. This helps to prevent void formation. The etchant also helps avoid void formation by preventing gap 406 from plugging during deposition. The etchant creates sloped sides to the carbon film deposited in the field regions 408, 410.

[0064] Referring next to FIG. 4B, gap 406 further fills with carbon as the pulsed carbon deposition process continues. However, portions of the carbon film 402 located on field regions 408, 410 in this stage of the deposition grow less quickly, or even decrease in thickness. This may be due to effects such as sputtering / redeposition and etching as the process continues. Next referring to FIG. 4C, gap 406 has filled without any voids. Further, as carbon film 402 begins to form an overburden over gap 406, the overall planarity of the carbon film 402 increases. This illustrates the self-planarization capabilities of the pulsed plasma carbon deposition process. Additional deposition time can lead to a highly planar and void-free carbon film 402, as illustrated in FIG. 4D, without having to perform cyclic deposition / etching. The self-planarization characteristics of the disclosed examples can result in the formation of highly planar carbon gapfill films even over substrates with variable topologies having gaps with multiple different widths and / or depths. Further, the disclosed example methods can deposit a carbon film without causing substrate damage of the magnitude caused by some cyclic deposition / etching processes. Also, as mentioned above, process conditions can be tuned such that carbon film 402 has a modulus higher within a range, for example, of 25-80 GPa, which is higher than that ordinarily achieved by cyclic etching / deposit! on processes.

[0065] In some examples, a carbon film formed using pulsed RF power as disclosed can have a density within a range of 1.2 to 1.7 g / cm3. In comparison, carbon films formed by cyclic deposition / etching processes can have densities on the order of 0.8 to 1.2 g / cm3. Further, in some examples, a carbon film formed using pulsed RF power as disclosed can have a modulus within a range of 25 - 80 GPa. In comparison, carbon films formed by cyclic deposition / etching processes can have moduli on the order of 5 to 25 GPa. Additionally, in some examples, carbon films formed using pulsed RF power as disclosed can have a stress on the order of -200 to -400 MPa. In comparison, carbon films formed by cyclic deposition / etching processes can have stress on the order of -150 to +50 MPa. Also, in some examples, carbon films formed using pulsed RF power as disclosed can have a refractive index on the order of 1.7 to 1.95.In comparison, carbon films formed by cyclic deposition / etching processes can have stress on the order of 1.5 to 1.7.

[0066] The LF RF power and / or HF RF power can be pulsed at any suitable pulse frequency during a pulsed plasma carbon deposition process. Examples include pulse frequencies of 2 hertz (Hz) to 10 kilohertz (kHz). In some such examples, the frequency at which the plasma is pulsed can include frequencies of 500 Hz to 1500 Hz. Further, the plasma pulses can have any suitable duty cycle. Examples include duty cycles within a range of 10-90%. Further, the HF RF power and LF RF power each can have any suitable magnitudes during a pulsed plasma deposition process. Examples include between 50 and 2500 watts (W) per processing station, per frequency of RF power. Some processing tools have multiple processing stations per processing chamber. Further some processing tools have multiple processing chambers, each with one or more processing stations. Thus, the ranges above can be scaled according to a number of processing stations used. As an example, a processing tool with four processing stations can utilize a HF RF power component of between 250 and 1000 W, and an LF RF power component of between 250 and 1000 W. In other examples, a plasma used in a pulsed plasma carbon deposition process can have one or more parameters outside of these ranges, such as a higher magnitude of LF RF power and / or HF RF power. As mentioned above, the LF RF component and the HF RF component can have any suitable frequences. An example LF RF frequency is 400 kHz. Example HF RF frequencies are 13.56 MHz and 27 MHz.

[0067] A pulsed plasma carbon deposition process according to the present disclosure can be performed using any suitable processing chamber pressure. As mentioned above, relatively lower processing chamber pressures can favor relatively more directional carbon deposition, while relatively higher processing chamber pressures can favor relatively more conformal carbon deposition. Example pressures for performing a pulsed plasma carbon deposition process include pressures of between 1 and 20 Torr.

[0068] As mentioned above, the processing gas mixture used to perform a pulsed plasma carbon deposition process includes a carbon-containing precursor and an etchant. Example carbon-containing precursors can 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 CiJLn 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 aromatic hydrocarbons, heterocyclic compounds, cyclic aliphatic hydrocarbons, and alkyl amines and other nitrogen-containing compounds, that are gas-phase under processing conditions and that include carbon-containing functional groups.

[0069] Example etchants include hydrogen (H2), other hydrogen-containing gases (e.g. ammonia, hydrazine) halogen-containing gases, and oxygen-containing gases. Example halogen-containing etchants 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 oxygen-containing etchants include carbon monoxide (CO), carbon dioxide (CO2), carbon oxysulfide (COS), sulfur dioxide (SO2), and molecular oxygen (O2).

[0070] Relatively high concentrations of etchant can be used in a processing gas mixture to perform a pulsed plasma carbon deposition process as disclosed, compared to etchant concentrations used in the deposition phase of a cyclic deposition / etch process. In some examples, a ratio of a mass flow of a hydrogencontaining etchant (e.g. hydrogen or ammonia) to a carbon-containing precursor is within a range of 2: 1 to 30: 1 (etchant: carbon-containing precursor). An oxygencontaining etchant, such as carbon dioxide, also may be used within this proportion range.

[0071] The disclosed examples further can be used to perform planar and void- free gapfill even on very wide gaps, such as gaps having a width of 150 nm or greater. Filling gaps of such dimensions can pose difficulties, and require cycles of deposition to fill the gap and etching to reduce the overburden on surfaces around the gap. However, by using pulsed plasma according to the disclosed examples, a gapfill of such very wide gaps can be performed by first depositing the film as described with regard to FIGS. 4A-4D to fill the gap and form an overburden of carbon film, and then modifying a gas mixture to convert the process from a net deposition regime to a net etching regime to reduce or remove the overburden. Modifying the gas mixture can comprise, for example, increasing a proportion of the etchant to the carbon-containingprecursor, while otherwise maintaining the pulse scheme used in the deposition. In other examples, a different pulse scheme can be used for the etching step. In the example of a pulsed LF / continuous wave HF RF plasma, the resulting etch can be topheavy, thereby etching prominences more quickly than other regions of the carbon film. The etch can be continued to remove carbon from a substrate surface adjacent to a gap, potentially without substantially etching carbon film in the gap. The term “without substantially etching” indicates that no additional deposition step is needed to refill carbon etched from within the gap after performing the top-heavy etching process.

[0072] FIGS. 5A-5C illustrate such an etching step. First, FIG. 5A illustrates substrate 500 with an example carbon film 502. The carbon film 502 fills a gap 504, and also forms prominences (e.g. prominence 506) over substrate regions (e.g. region 508) adjacent to the gap 504. FIG. 5 A is shown before etching is performed. Next, FIG. 5B shows the carbon film 502 after a first period of etching. As can be seen, while the entire surface of the carbon film 502 has been etched, the prominences 506 have been etched at a higher rate than the carbon film over the gap 504. Continuing the etching process until the carbon film is removed from the substrate regions 508 results in the carbon film 502 remaining as a void-free fill within the gap 504. Thus, the disclosed example deposition process can be modified to an etching process by controlling a proportion of carbon-containing precursor to etchant used in the process to perform a top-heavy etch that can remove a carbon film overburden without damaging portions of the carbon film within a gap.

[0073] FIG. 6 shows a flow diagram of an example method 600 for depositing a carbon film on a substrate. At 602, the method comprises introducing a carbon- containing precursor and etchant to a processing chamber during a deposition process. In some examples, at 604, the method comprises flowing a ratio of etchant: carbon- containing precursor that is within a range of 2: 1 to 30: 1. 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 CnEbn 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 include aromatic hydrocarbons, heterocyclic compounds, cyclic aliphatic hydrocarbons, and alkyl amines and other nitrogen-containing compounds, that are gasphase under processing conditions and that include carbon-containing functionalgroups. Example etchants include hydrogen (H2), other hydrogen-containing gases (e.g. ammonia, hydrazine) halogen-containing gases, and oxygen-containing gases. Example halogen-containing etchants 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 etchants include carbon monoxide (CO), carbon dioxide (CO2), carbon oxysulfide (COS), sulfur dioxide (SO2), and molecular oxygen (O2).

[0074] Continuing, at 606, method 600 comprises controlling a RF power supply to pulse a plasma during the deposition process. Pulsing the plasma can cause deposition of a substantially void-free carbon film on the substrate and in a gap on the substrate. As described above, net deposition may occur during the RF power “on” stage of the pulsed plasma cycle and a net etch may occur during the RF power “off’ stage of the pulsed plasma cycle. In some examples, at 608, method 600 can use a single frequency RF power. In some examples, at 610, the method can use a LF RF power and a HF RF power to form a multi-frequency plasma.

[0075] In some examples, at 612, controlling the RF power supply to pulse the plasma comprises controlling the RF power supply to pulse the LF RF power. In some examples, at 614, the method comprises pulsing the LF RF power and providing continuous wave HF RF power during the deposition process. Additionally or alternatively, in some examples, at 616, controlling the RF power supply to pulse the plasma comprises controlling the RF power supply to pulse the HF RF power. In some examples, at 618, the method comprises pulsing the HF RF power and providing continuous wave LF RF power during the deposition process. In some examples, method 600 can comprise pulsing both the LF RF power at 612 and pulsing the HF RF power at 616.

[0076] In some examples, at 620, the method 600 comprises pulsing the plasma at a duty cycle of 10% to 90%. In other examples, any other suitable duty cycle can be used. In some examples, at 622, the method comprises pulsing the plasma at a pulse frequency within a range of 2 Hz to 10 kHz. In some such examples, a pulse frequencyof 500 Hz to 1500 Hz can be used. In other examples, a pulse frequency outside these ranges can be used.

[0077] In some examples, at 624, controlling the RF power supply to pulse the plasma causes deposition of a carbon film comprising a modulus within a range of 25 to 80 GPa. In some such examples, the deposited carbon film comprises a modulus greater than 40 GPa. In some examples, at 626, the deposited carbon film comprises a density within a range of 1.2 to 1.7 g / cm3. In some examples, at 628, the deposited carbon film comprises a refractive index of 1.7 to 1.95. In other examples, the deposited carbon film may comprise properties outside these ranges.

[0078] Continuing, in some examples, at 630, method 600 optionally comprises adjusting a ratio of the carbon-containing precursor and etchant to cause a net etching of the carbon film. In some examples, adjusting the ratio can comprise increasing a proportion of the etchant to the carbon-containing precursor. As discussed above, this can help to reduce or remove an overburden of carbon formed on the substrate.

[0079] FIG. 7 schematically shows a schematic depiction of a processing tool 700 configured for performing plasma-enhanced chemical vapor deposition (PECVD). Processing tool 700 comprises a processing chamber 702 and a substrate holder 704 within the processing chamber. The substrate holder 704 is configured to support a substrate 706 disposed within processing chamber 702. The substrate holder 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.

[0080] The processing tool 700 further comprises an optional secondary purge gas outlet 711. Secondary purge gas outlet 711 is configured to form secondary purge gas flow around the outside edge of 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 precursor source 716, an etchant source 718, and an inert gas source 722 to the processing chamber. The flow control hardware 712 can include any suitable components. 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 fluidconnection 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 aliphatic hydrocarbons, aromatic hydrocarbons, heterocyclic compounds, and alkyl amines.

[0083] The etchant source 718 can comprise any suitable substance or substances that can etch an amorphous carbon film during film deposition. Example etchants can include one or more of hydrogen (Eb), ammonia (NH3), hydrazine (N2H2), chlorine (Ch), fluorine (F2), bromine (Bn), iodine (I2), hydrofluoric acid (HF), hydrochloric acid (HC1), hydrobromic acid (HBr), hydroiodic acid (HI), nitrogen trifluoride (NF3), boron trifluoride (BF3), sulfur hexafluoride (SFe), a halocarbon gas having a general formula CaXb (where X comprises one or more of fluorine, chlorine, bromine, or iodine and where a = 1-10), a halohydrocarbon gas having a general formula CaHbXc (where X comprises one or more of fluorine, chlorine, bromine, or iodine and where a = 1-10), carbon monoxide (CO), carbon dioxide (CO2), carbon oxysulfide (COS), sulfur dioxide (SO2), or molecular oxygen (O2).

[0084] The inert gas source 722 comprises any suitable inert gas. Examples include argon, helium, neon, krypton, and xenon, as well as nitrogen in some processing environments.

[0085] 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.

[0086] 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 holder 704, and showerhead 710 is configured as a grounded opposing electrode. As mentioned above, use of a powered substrate holder helps attract ions towards the substrate, for example, to provide for ion-based directional carbon film growth. In other examples, the RF power source 734 can supply RF power to showerhead 710, and substrate holder 704 can be grounded. In the depicted example, a capacitively coupled plasma can be formed in processing chamber 702 between showerhead 710 and substrate holder 704. In other examples, an inductively coupled plasma can be used. The processing tool 700 further includes a matching network 736 for impedance matching of the RF power source 734.

[0087] In some examples, 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 to form a multi-frequency plasma. 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. In other examples, the radiofrequency power source 734 is configured to supply a single frequency (e.g. HF) of RF power.

[0088] The radiofrequency power source 734 further is configured to pulse one or more of the HF RF power and the LF RF power during a carbon film deposition process. The term “pulse” with reference to a plasma indicates that the power of one or both of the HF RF power and the LF RF power is modulated with time. The modulation can include reducing a power partially, or fully cutting the power, between pulses. A higher power of a pulsed plasma cycle can be referred to as an “on” portion of the cycle, and a lower power of a pulsed plasma cycle can be referred to as an “off’ portion of the cycle, even if the RF power of the pulsed frequency is not fully cut to zero during the “off’ portion of the cycle. The term “continuous wave” is used to refer to RF power that is not pulsed during a deposition process, but rather is maintained at a set power level. It will be understood that the physics of a pulsed plasma (e.g. electron temperature, ion energy, etc.) can be different from the physics of a continuous wave plasma of a same average power.

[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.

[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. The 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 subsystem 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 subsystem can include one or more processors configured to execute software instructions. Additionally or alternatively, the logic subsystem can include one or more hardware or firmware logic subsystems configured to execute hardware or firmware instructions. Processors of the logic subsystem 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 subsystem 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 subsystem 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 subsystem to implement themethods 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, semiconductor memory, and / or magnetic memory, 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 subsystem, and thus transform the state of the storage subsystem, 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 voicerecognition, 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 allow computing 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 processing tool, comprising: a processing chamber; a substrate holder; a showerhead; flow control hardware configured to connect one or more processing gas sources with the showerhead; a radiofrequency (RF) power supply configured to provide RF power to form a plasma between the substrate holder and the showerhead; and a controller configured to control the flow control hardware to introduce a flow of a carbon-containing precursor and an etchant into the processing chamber through the showerhead during a deposition process, and to control the RF power supply to pulse the plasma during the deposition process.

2. The processing tool of claim 1, wherein the RF power supply is configured to supply a lower frequency (LF) RF power and a higher frequency (HF) RF power to form a multi-frequency plasma during the deposition process.

3. The processing tool of claim 2, wherein the controller is configured to control the RF power supply to pulse the LF RF power while providing continuous wave HF RF power during the deposition process.

4. The processing tool of claim 2, wherein the controller is configured to control the RF power supply to pulse the HF RF power while providing continuous wave LF RF power during the deposition process.

5. The processing tool of claim 2, wherein the controller is configured to control the RF power supply to pulse the HF RF power and to pulse the LF RF power during the deposition process.

6. The processing tool of claim 1, wherein the RF power supply is configured to provide a single frequency of RF power.

7. The processing tool of claim 1, wherein the etchant comprises one or more of hydrogen (H2), ammonia (NH3), hydrazine (N2H2), chlorine (Ch), fluorine (F2), bromine (Bn), iodine (I2), hydrofluoric acid (HF), hydrochloric acid (HC1), hydrobromic acid (HBr), hydroiodic acid (HI), nitrogen trifluoride (NF3), boron trifluoride (BF3), sulfur hexafluoride (SFe), a halocarbon gas having a general formula CaXb (where X comprises one or more of fluorine, chlorine, bromine, or iodine and where a = 1-10), a halohydrocarbon gas having a general formula CaHbXc (where X comprises one or more of fluorine, chlorine, bromine, or iodine and where a = 1-10), carbon monoxide (CO), carbon dioxide (CO2), carbon oxysulfide (COS), sulfur dioxide (SO2), or molecular oxygen (O2).

8. The processing tool of claim 1, wherein the carbon-containing precursor comprises one or more of an alkane having a general formula CnH2n+2 where n is an integer in a range of 1 to 10, an alkene having a general formula GTHn where n = 2 to 10, an alkyne having a general formula CnH2n-2 where n = 2 to 10, an aromatic hydrocarbon, an aliphatic cyclic hydrocarbon, or an alkyl amine.

9. The processing tool of claim 1, wherein the controller is configured to control the flow control hardware to flow a ratio of etchant: carbon-containing precursor of 2: 1 to 30:1 into the processing chamber.

10. The processing tool of claim 1, wherein the controller is configured to control the RF power supply to pulse the plasma at a pulse frequency of 2 hertz to 10 kilohertz.

11. The processing tool of claim 1, wherein the controller is configured to control the RF power supply to pulse the plasma at a duty cycle of 10 - 90%.

12. The processing tool of claim 1, wherein the controller is configured to adjust a ratio of the carbon-containing precursor and the etchant after a period of carbon film deposition to cause a net etching of the carbon film.

13. A method, comprising: introducing a flow of a carbon-containing precursor and an etchant into a processing chamber during a deposition process; andcontrolling a radiofrequency (RF) power supply to pulse a plasma in the processing chamber during the deposition process.

14. The method of claim 13, wherein controlling the RF power supply comprises controlling the RF power supply to supply a lower frequency (LF) RF power and a higher frequency (HF) RF power to form a multi-frequency plasma during the deposition process.

15. The method of claim 14, wherein controlling the RF power supply to pulse the plasma comprises controlling the RF power supply to pulse the LF RF power while providing continuous wave HF RF power during the deposition process.

16. The method of claim 14, wherein controlling the RF power supply to pulse the plasma comprises controlling the RF power supply to pulse the the HF RF power while providing continuous wave LF RF power during the deposition process.

17. The method of claim 14, wherein controlling the RF power supply to pulse the plasma comprises controlling the RF power supply to pulse the HF RF power and to pulse the LF RF power during the deposition process.

18. The method of claim 13, wherein controlling the RF power supply comprises controlling the RF power supply to provide a single frequency of RF power during the deposition process.

19. The method of claim 13, wherein introducing the flow of the carbon-containing precursor and the etchant into the processing chamber comprises flowing a ratio of etchant: carbon-containing precursor of 2: 1 to 30: 1 into the processing chamber.

20. The method of claim 13, further comprising adjusting a ratio of the carbon- containing precursor and the etchant after a period of carbon film deposition to cause a net etching of the carbon film.

21. A method for carbon gapfill, the method comprising:flowing a carbon-containing precursor and an etchant into a processing chamber; controlling a radiofrequency (RF) power supply to form a plasma in the processing chamber, thereby depositing a carbon film in a gap on a substrate disposed in the processing chamber, the carbon film being substantially void-free; and while depositing the carbon film, controlling the RF power supply to pulse the plasma so that the deposited carbon film comprises a modulus of elasticity within a range of 25 to 80 GPa.

22. The method of claim 21, wherein controlling the RF power supply comprises controlling the RF power supply to supply a lower frequency (LF) RF power and a higher frequency (HF) RF power to form a multi-frequency plasma during the deposition process.

23. The method of claim 22, wherein controlling the RF power supply to pulse the plasma comprises controlling the RF power supply to pulse the LF RF power while providing continuous wave HF RF power during the deposition process.

24. The method of claim 21, wherein the deposited carbon film comprises a density within a range of 1.2 to 1.7 g / cm3.

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