Cyclic etching between deposition cycles

Abstract

A method for filling a recessed feature on a substrate in a processing chamber comprises performing a deposition process comprising a plurality of deposition cycles to form a film within the recessed feature. The method further comprises shaping the film to form a tapered profile with respect to a depth of the film within the recessed feature by performing a cyclic etching process during the deposition process. The at least one cyclic etching process comprises a plurality of etching cycles. An etching cycle of the plurality of etching cycles comprises exposing the substrate to an etching plasma comprising an etching agent to etch a portion of the film within the recessed feature. The etching cycle further comprises purging the processing chamber. The etching cycle further comprises exposing the substrate to a passivation plasma to remove residual etching agent from within the recessed feature.

Description

CYCLIC ETCHING BETWEEN DEPOSITION CYCLESBACKGROUND

[0001] Electronic device fabrication involves many steps of material deposition, patterning, and removal to form integrated circuits on substrates. Various methods can be used to deposit films on substrates. For example, atomic layer deposition (ALD) can be used to form a film on a substrate in a layer-by-layer manner using one or more ALD cycles. An ALD cycle comprises a dose phase and a conversion phase. In the dose phase, a film precursor is adsorbed to a substrate surface in a selflimiting reaction. The processing chamber is purged. Then, in the conversion phase, the adsorbed film precursor is chemically converted to a film layer. The film layer conforms to a shape of the substrate surface. Additional cycles can be used to deposit additional layers to form a thicker film.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 filling a gap on a substrate with a film by performing a cyclic etching process between deposition cycles of a deposition process. One example provides a method for filling a recessed feature on a substrate in a processing chamber. The method comprises performing a deposition process comprising a plurality of deposition cycles to form a film within the recessed feature. The method further comprises shaping the film during the deposition process to form a tapered profile with respect to a depth of the film within the recessed feature by performing a cyclic etching process during the deposition process. The cyclic etching process comprises a plurality of etching cycles. An etching cycle of the plurality of etching cycles comprises exposing the substrate to an etching plasma comprising an etching agent to etch a portion of the film within the recessed feature. The etching cycle further comprises purging the processing chamber. The etching cycle further comprisesexposing the substrate to a passivation plasma to remove residual etching agent from within the recessed feature.

[0004] In some such examples, the method comprises, after the cyclic etching process, performing one or more additional deposition cycles.

[0005] Additionally or alternatively, in some such examples, the method comprises performing another cyclic etching process after performing the one or more additional deposition cycles.

[0006] Additionally or alternatively, in some such examples, the recessed feature comprises an aspect ratio of 1 : 1 to 1 :300.

[0007] Additionally or alternatively, in some such examples, exposing the substrate to the etching plasma comprises controlling a duration of etching plasma exposure to control a depth within the recessed feature of the portion of the film that is etched.

[0008] Additionally or alternatively, in some such examples, exposing the substrate to the etching plasma comprises controlling one or more of a flow rate of the etching agent or radiofrequency power of the etching plasma to control a depth within the recessed feature of the portion of the film that is etched.

[0009] Additionally or alternatively, in some such examples, shaping the film comprises controlling a number of the etching cycles performed to control an angle of taper.

[0010] Additionally or alternatively, in some such examples, etching the portion of the film comprises etching one or more of silicon dioxide, silicon carbide, silicon oxycarbide, silicon nitride, silicon carbonitride, silicon oxycarbonitride, or silicon oxynitride.

[0011] Additionally or alternatively, in some such examples, exposing the substrate to the etching plasma comprising the etching agent comprises exposing the substrate to a reactive halogen species in the etching plasma.

[0012] Additionally or alternatively, in some such examples, exposing the substrate to the reactive halogen species comprises exposing the substrate to a fluorine- containing species.

[0013] Additionally or alternatively, in some such examples, exposing the substrate to the etching plasma comprises exposing the substrate to a plasma with a higher-frequency radiofrequency energy component and a lower-frequency radiofrequency energy component.

[0014] Additionally or alternatively, in some such examples, exposing the substrate to the passivation plasma comprises exposing the substrate to a plasma with a higher-frequency radiofrequency energy component and a lower-frequency radiofrequency energy component.

[0015] Additionally or alternatively, in some such examples, exposing the substrate to the passivation plasma comprises exposing the substrate to a reducing plasma.

[0016] Additionally or alternatively, in some such examples, exposing the substrate to the reducing plasma comprises exposing the substrate to a hydrogencontaining plasma.

[0017] Another example provides a processing tool. The processing tool comprises a processing chamber. A substrate support is disposed in the processing chamber. The processing tool further comprises flow control hardware configured to control flows of processing chemicals into the processing chamber. The processing tool further comprises a radiofrequency (RF) power source operable to form a plasma in the processing chamber. The processing tool further comprises a controller. The controller is configured to control the flow control hardware and the RF power source to perform a deposition process comprising a plurality of deposition cycles to form a film within the recessed feature. The controller is further configured to control the flow control hardware and the RF power source to shape the film to form a tapered profile with respect to a depth of the film within the recessed feature during the deposition process by performing a cyclic etching process comprising a plurality of etching cycles during the deposition process. The controller is configured to control the flow control hardware and the RF power source to, during an etching cycle of the plurality of etching cycles, expose the substrate to an etching plasma comprising an etching agent to etch a portion of the film within the recessed feature, to purge the processing chamber, and to expose the substrate to a passivation plasma to remove residual etching agent from within the recessed feature.

[0018] In some such examples, the controller is further configured to control the flow control hardware and the RF power source to, after the cyclic etching process, perform one or more additional deposition cycles.

[0019] Additionally or alternatively, in some such examples, the etching agent comprises a reactive halogen species.

[0020] Additionally or alternatively, in some such examples, the reactive halogen species comprises a fluorine-containing species.

[0021] Another example provides a method for filling a recessed feature on a substrate in a processing chamber. The method comprises performing a deposition process comprising a plurality of deposition cycles to form a silicon oxide film within the recessed feature. The method further comprises, during the deposition process, shaping the silicon oxide film to form a tapered profile with respect to a depth of the film within the recessed feature by performing a cyclic etching process during the deposition process. The cyclic etching process comprises a plurality of etching cycles. An etching cycle of the plurality of etching cycles comprises exposing the substrate to an etching plasma comprising a fluorine-containing etching agent to etch a portion of the silicon oxide film within the recessed feature. The method further comprises purging the processing chamber. The method further comprises exposing the substrate to a passivation plasma to remove residual fluorine-containing etching agent from within the recessed feature.

[0022] In some such examples, the method further comprises, after the cyclic etching process, performing one or more additional deposition cycles.BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 schematically shows an example processing tool.

[0024] FIG. 2 shows a flow diagram depicting an example method for performing a gapfill process.

[0025] FIGS. 3 A-3G schematically illustrate formation of a tapered profile in a film during an example gapfill process by performing an example cyclic etching process during film deposition.

[0026] FIG. 4 schematically illustrates the effect of varying etching parameters when forming a tapered profile in a film using example cyclic etching processes.

[0027] FIGS. 5A-5B show a flow diagram depicting another example method for performing a gapfill process.

[0028] FIG. 6 shows a schematic diagram of an example computing system.DETAILED DESCRIPTION

[0029] The term “atomic layer deposition” (ALD) generally represents a process in which a film is formed on a substrate in individual film layers by sequentialALD cycles. An ALD cycle comprises a dose phase and a conversion phase. In the dose phase, a film precursor is adsorbed to a substrate surface in a self-limiting reaction. The processing chamber is purged. Then, in the conversion phase, the adsorbed film precursor is chemically converted to a film layer. Examples of ALD processes comprise plasma-enhanced ALD (PEALD) and thermal ALD (TALD). PEALD and TALD respectively utilize a plasma of a reactive gas and heat to facilitate a chemical conversion of a film precursor adsorbed to a substrate to a film on the substrate. The terms “growth”, “deposition”, and variants thereof, also can be used to refer to film formation.

[0030] The term “angle of taper” generally represents an angle between a surface of a film outside of a gap and a surface of the film deposited over a portion of a sidewall of the gap.

[0031] The term “aspect ratio” generally represents a ratio between a depth of a gap and an average width of the gap.

[0032] The term “depth” generally represents a distance from a plane of a substrate surface to a position within a gap.

[0033] The term “etching” generally represents a chemical process by which material is removed from a substrate.

[0034] The term “etching agent” generally represents a chemical substance used to remove materials from a substrate. An etching agent can be used in a plasma etching process. Example etching agents include reactive halogen species, such as fluorine- containing species. Examples of fluorine-containing etching agents include molecular fluorine (F2), hydrogen fluoride (HF), nitrogen trifluoride (NF3), boron trifluoride (BF3), sulfur hexafluoride (SFe), and fluorocarbon compounds having a general formula CaHbFc, where a = 1-10.

[0035] The term “feature” generally represents substrate topology.

[0036] The term “film” generally represents a layer of material deposited on a substrate.

[0037] The term “flow control hardware” generally represents components configured to place one or more chemical sources in controllable fluid connection with a processing chamber.

[0038] The term “gap” generally represents a recessed feature in a substrate.

[0039] The term “gapfill” generally represents a process of filling a gap with a deposited film.

[0040] The term “passivation” generally represents removal of at least some residual etching agent from a substrate.

[0041] The term “plasma” generally represents an ionized gas.

[0042] The term “processing chamber” generally represents an enclosure in which chemical and / or physical processes are performed on substrates.

[0043] The term “processing tool” generally represents a machine comprising a processing chamber and other hardware configured to enable processing to be carried out in the processing chamber.

[0044] The terms “purge” and variants thereof generally represent processes in which unwanted species are removed from a processing chamber.

[0045] The term “radiofrequency (RF) power source” generally represents a component of a processing tool configured to provide power to form a plasma for processing substrates.

[0046] The term “substrate” generally represents any object on which a film can be deposited.

[0047] The term “substrate support” generally represents a structure for supporting a substrate in a processing chamber during substrate processing.

[0048] The term “taper” generally represents a profile of a film that increases in thickness as a function of increasing depth within a gap.

[0049] As introduced above, atomic layer deposition (ALD) can be used to form a film on a substrate in a layer-by-layer manner using a plurality of ALD cycles. Each ALD cycle forms a layer of the film. ALD can be used to form a highly conformal film with a thickness that does not substantially vary across a substrate surface. As such, ALD can be used to deposit material within a gap in a gapfill process.

[0050] However, some gaps can have reentrant structures. A reentrant structure is a location in a gap that is narrower than a location deeper within the gap. When filling a gap using ALD, conformal film growth can cause the film to pinch off at the reentrant structure. This can form a void inside the gap at a location deeper than the reentrant structure. Such voids can cause problems in later processing steps. Further, even in gaps without reentrant structures, the use of ALD to perform gapfill can form a seam where film growth fronts meet within the gap. The seam region can have a lower quality than other regions of the gapfill film.

[0051] To avoid formation of a void and / or to help improve seam quality, sputtering and / or plasma etching steps can be used at selected points in an ALD process.These methods can be referred to as deposition-sputter-deposition and deposition-etch- deposition methods. The sputtering and / or etching steps are used to form a tapered film growth profile within the gap by removing more material from a region of the gap closer to a gap opening, and less material from a gap region farther from the gap opening. This helps to fill a gap from the bottom up, and thereby avoid pinching off the gap at a reentrant structure. Filling the gap from the bottom up also can provide for a higher quality seam region within the gap than the use of conformal ALD to fill the gap.

[0052] However, removing more material from a top portion of the gap and less material from within the gap in such a sputtering or chemical etching process can be challenging. For example, a gas-phase chemical etching agent can diffuse deeper into the gap than desired. This can result in removal of material from deeper into the gap than desired. As a result, conformal growth can still occur, due to the etching occurring throughout the depth of the gap. Likewise, it can be challenging to control sputter depth and obtain a deeper taper profile due to directional travel of the particles. In addition, film material removed from deeper within a gap by sputtering can re-deposit closer to an opening of the gap. This can contribute to the formation of a reentrant structure that can result in void formation.

[0053] Accordingly, examples are disclosed that relate to performing one or more cyclic etching processes during a deposition process to help fill a gap or other type of recessed feature in a bottom-up manner. Each cyclic etching process comprises a plurality of etching cycles that shape a film deposited in one or more prior deposition cycles. An etching cycle of the plurality of etching cycles comprises exposing the substrate to an etching plasma comprising an etching agent to etch a portion of the film within the gap. The etching plasma is controlled to cause a greater etching rate within a gap closer to an opening of the gap than deeper within the gap. The etching cycle further comprises a purging step and a passivation step. The purging removes at least some residual etching agent from the chamber. However, residual etching agent can remain on the substrate. For example, a purge process may not remove residual etching agent located at or near a bottom of the gap. This residual etching agent can contribute to higher than desired etching rates at such gap locations in subsequent etching cycles. Thus, in the passivation step, a passivation plasma is used to remove residual etching agent from within the gap. This can help to prevent unwanted etching from occurring deeper within the gap as the cyclic etching process proceeds.

[0054] As described in more detail below, a duration of the etching plasma exposure controls penetration depth of the etching agent into the gap in each etching cycle. A number of etching cycles controls an amount of material removed from the film. By controlling these variables, a penetration depth of the etching agent and an amount of material removed from the film with each etching cycle of the cyclic etching process can be controlled independently. Further, the passivation step helps to reduce unwanted etching within the gap below a desired depth of etching. These factors allow control of a taper angle of the film being deposited within the gap. As a result, the cyclic etching process allows a gap to be controllably filled in a bottom-up manner, without forming voids inside the gap, and with a higher quality seam area than other ALD gapfill methods. In addition, gapfill using a cyclic etching process during deposition according to the disclosed examples can be performed with greater throughput than by using deposition-etch-deposition or deposition-sputter-deposition processes.

[0055] FIG. 1 schematically shows an example processing tool 100 that can be used to perform an ALD gapfill process comprising a cyclic etching process according to the present disclosure. The processing tool 100 comprises a processing chamber 102. The processing chamber 102 comprises at least one processing station 104. The processing station 104 comprises a substrate support 106 for supporting a substrate 108. In some examples, the substrate support 106 comprises a substrate heater 110 configured to heat the substrate 108. In other examples, the substrate heater 110 can be omitted.

[0056] The processing station 104 further comprises a processing chemical outlet 112. In the depicted example, the processing chemical outlet 112 comprises a showerhead for directing a processing chemical across an area of substrate 108. In other examples, the processing station 104 alternatively or additionally comprises a nozzle or other processing chemical outlet structure.

[0057] The processing tool 100 further comprises a film precursor source 118. The film precursor source 118 can take any suitable form. In some examples, the film precursor source can comprise a compressed gas. In other examples, the film precursor source can comprise a condensed phase film precursor that is vaporized for delivery to a processing chamber.

[0058] In some examples, the film precursor source comprises a silicon- containing precursor. The term “silicon-containing precursor” generally represents any compound that can be introduced into a processing chamber to form a silicon-containing film on the substrate in an ALD process. Example silicon-containing films include silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, silicon oxycarbide, silicon carbonitride, and silicon oxycarbonitride. Example silicon- containing precursors for forming silicon-containing films can comprise materials having the general structure:where Ri, R2 and R3 can be the same or different substituents. In various examples, Ri, R2, and R3 can include silanes, siloxy groups, amines, halides, hydrogen, or organic groups such as alkylamines, alkoxy, alkyl, alkenyl, alkynyl, and cyclic groups (such as aromatic groups).

[0059] Example silicon-containing precursors include silane and polysilanes, such as disilane, trisilane, and tetrasilane. Another example is trisilylamine. Silane- based precursors can include partially and substituted variants of silane and polysilanes.

[0060] In some examples, the silicon-containing precursor is a siloxane. Siloxanes include materials having Si-O-Si linkages. Example siloxanes include octamethylcyclotetrasiloxane (OMCTS), octamethoxydodecasiloxane (OMODDS), and tetramethylcyclotetrasiloxane (TMCTS).

[0061] In some examples, the silicon-containing precursor is an alkoxysilane. Example alkoxysilanes include tetramethoxysilane (TMOS), diethoxymethylsilane (DEMS), di ethoxy silane (DES), dimethoxymethylsilane, dimethoxysilane (DMOS), methyl-diethoxysilane (MDES), methyl-dimethoxysilane (MDMS), t-butoxydisilane, triethoxysilane (TES), and trimethoxysilane (TMS or TriMOS).

[0062] In some examples, the silicon-containing precursor is an aminosilane. Example aminosilanes include bisdiethylaminosilane, diisopropylaminosilane, bis(t- butylamino) silane (BTBAS), di-sec-butylaminosilane, and tris(dimethylamino)silane (3DMAS).

[0063] Other specific examples of silicon-containing precursors include tetraethylorthosilicate (TEOS), methylsilane, trimethylsilane (3MS), ethylsilane, butasilanes, pentasilanes, octasilanes, heptasilane, hexasilane, cyclobutasilane,cycloheptasilane, cyclohexasilane, cyclooctasilane, cyclopentasilane, 1,4-dioxa- 2,3,5,6-tetrasilacyclohexane, triethoxysiloxane (TRIES), and tetraoxymethylcyclotetrasiloxane (TOMCTS).

[0064] The processing tool 100 further comprises a reactant source 128 configured to supply a reactant into the processing chamber 102. In some examples, the reactant comprises an oxidant. Example oxidants include oxygen (O2), ozone (O3), hydrogen peroxide (H2O2), water (H2O), and nitrogen oxides such as nitrous oxide (N2O). The reactant is configured to react with the film precursor to form a film on the substrate 108.

[0065] The processing tool 100 further comprises an etching agent source 130. The etching agent source 130 is configured to supply an etching agent into the processing chamber 102. In some examples, the etching agent source 130 comprises a halogen or a halogenated compound. For example, the etching agent source 130 can include molecular fluorine (F2) or a fluorine-containing compound. Examples of fluorine-containing compounds that can form reactive halogen species include molecular fluorine (F2), hydrogen fluoride (HF), nitrogen trifluoride (NF3), boron trifluoride (BF3), sulfur hexafluoride (SFe), and fluorocarbon compounds having a general formula CaHbFc, where a = 1-10. Such substances react with and remove at least a portion of a material from a substrate in an etching process.

[0066] The processing tool 100 further comprises an inert gas source 132. The inert gas source 132 is configured to supply an inert gas to use, for example, as a plasma gas and / or a purge gas. Examples of inert gases include argon (Ar), helium (He), neon (Ne), krypton (Kr), and xenon (Xe). Nitrogen (N2) also can be used as an inert gas in some examples.

[0067] The processing tool 100 further comprises flow control hardware 120 that controllably delivers processing chemical flows to the processing station 104 from the film precursor source 118, the reactant source 128, and / or the inert gas source 132. The flow control hardware 120 is operable to selectively direct a flow of one or more processing chemicals received from respective processing chemical source(s) between a dose path fluidly coupled with the processing station 104 and a divert path fluidly coupled with exhaust system 131.

[0068] Processing tool 100 further comprises a RF power source 144 configured to form a plasma for processing substrate 108. In the depicted example, RF power source 144 is electrically connected to substrate support 106. Processingchemical outlet 112 is configured as a grounded opposing electrode in this example. In other examples, the RF power source 144 can supply RF power to the processing chemical outlet 112. In further examples, RF power can be provided to both the processing chemical outlet 112 and substrate support 106. In further examples, the RF power source 144 can apply power to an inductive coil to form an inductively coupled plasma (ICP). In other examples, the RF power source 144 can be used to form a capacitively coupled plasma (CCP). In yet further examples, processing tool 100 can include a remote plasma generator for generating a plasma at a location remote from processing station 104. Processing tool 100 further comprises a matching network 146 for impedance matching of the RF power source 144.

[0069] The RF power source 144 can be configured for any suitable frequency and power. Examples of suitable frequencies include 400 kHz, 13.56 MHz, 27MHz, 60Mz, and 90MHz. Examples of suitable powers include powers between 0 and 6500 watts. In some examples, the RF power source 144 is configured to operate at a plurality of different frequencies and / or powers. In some such examples, a plasma can be formed with a first, higher frequency RF power component and a second, lower frequency RF power component. The second, lower frequency RF power component can be used to direct ions toward a substrate surface with more kinetic energy compared to a plasma that omits the lower frequency RF component. This can be used for film densification and / or sputtering. A lower frequency RF component can have a similar power range as a higher frequency RF component. The example power ranges given above can be for a single chamber or station processing tool or a multi-chamber or multi-station processing tool. In general, an RF plasma power used to perform a process in a multi-station or multi-chamber tool is a multiple of the RF plasma power used to perform the process on at a single processing station. As more specific examples, an RF power range for a dual chamber processing tool can be double or approximately double the RF power range for performing the same process in a single processing chamber tool. Likewise, the RF power range for a single processing chamber tool can be approximately tripled for a three-chamber processing tool, approximately quadrupled for a four-chamber processing tool, and so forth.

[0070] The processing tool 100 further comprises a controller 148. The controller 148 is operatively coupled to substrate heater 110, flow control hardware 120, exhaust system 131, and RF power source 144, among other components. The controller 148 is configured to control various functions of the processing tool 100. Forexample, the controller 148 is configured to control the processing tool 100 to fill a gap on the substrate 108 using an ALD process with at least one cyclic etching process between ALD cycles. Example processes for filling gaps are described in more detail below.

[0071] For example, the controller 148 is configured to operate substrate heater 110 to heat the substrate heater 110 to a selected temperature. The controller 148 is also configured to operate flow control hardware 120 to flow a selected processing chemical or mixture of processing chemicals, such as film precursors, reactants, and purge gases, at selected rates and at selected times into processing chamber 102. The controller 148 is further configured to operate exhaust system 131 to remove residual processing chemicals from processing chamber 102. The controller 148 is configured to operate flow control hardware 120 and exhaust system 131 to control a pressure inside processing chamber 102. The controller 148 can comprise any suitable computing system, examples of which are described below with reference to FIG. 6.

[0072] FIG. 2 shows a flow diagram depicting an example method 200 for filling a gap on a substrate in a processing chamber. The following description of the method 200 is provided with reference to FIG. 1 above and FIGS. 3A-6 below. It will be appreciated by one of ordinary skill in the art without undue experimentation that the method 200 also can be performed in other contexts.

[0073] At 202, the method 200 comprises performing a deposition cycle to form a film layer within the gap. As indicated by the “NO” paths between 204 and 206 and between 206 and 202, the deposition process comprises performing a plurality of deposition cycles to fill a gap on a substrate, where each deposition cycle forms a film layer. In some examples, 10-1000 deposition cycles (e.g., ALD cycles) are performed. In some more specific examples, 10-500 deposition cycles are performed in a gapfill process. In further more specific examples, 50-200 deposition cycles are performed in a deposition process.

[0074] FIG. 3 A shows a highly magnified schematic cross-sectional view of an example substrate 302. The substrate 302 comprises a gap 304. The gap 304 has an aspect ratio that comprises a ratio between a depth of the gap 304 and an average width of the gap 304. In some examples, the aspect ratio is in a range of 1 : 1 to 1 :300. In other examples, a gap that is filled using the disclosed example gapfill methods can have an aspect ratio outside of this range.

[0075] The gap 304 comprises a slightly narrower width closer to an opening of the gap 304 than deeper within the gap 304. This can be referred to as a reentrant structure.

[0076] The substrate 302 further comprises a film 306 that has been deposited on the substrate 302, including within the gap. Film 306 is a partially-deposited gapfill film. In some examples, the film 306 comprises a silicon-containing film. For example, the film 306 can comprise one or more of silicon oxide, silicon carbide, silicon oxycarbide, silicon nitride, silicon carbonitride, silicon oxycarbonitride, or silicon oxynitride. It will be appreciated by one of ordinary skill in the art, without undue experimentation, that the film 306 can comprise any other suitable material that can be deposited and etched according to the present disclosure.

[0077] Film 306 has been formed by a plurality of ALD cycles. As ALD can be used to form conformal films, film 306 conforms to the reentrant structure of the gap 304. As such, film 306 also comprises a reentrant structure, with a narrower portion 310 closer to an opening of the gap 304 and a wider portion 312 deeper within the gap. Continued deposition of conformal film layers to thicken film 306 can form a void if the growth fronts of the conformal film merge at narrower portion 310 before merging at wider portion 312.

[0078] Thus, to avoid forming a void as the gapfill process continues, and referring again to FIG. 2, the method 200 comprises, at 206, comprises performing at least one cyclic etching process 206 between deposition cycles. As described in more detail below, performing the cyclic etching process results in shaping the film to form a tapered profile with respect to a depth of the film within the gap. This allows the gapfill process to proceed in a bottom up manner without forming any voids. While cyclic etching is depicted in the example of FIGS. 3A-3G as being performed when filling a gap comprising a reeentrant structure, in other examples, a gapfill process according to the present disclosure also can be used to fill a gap without a reentrant structure. In such examples, the cyclic etching can help to improve a seam quality in an ALD gapfill film.

[0079] At 208, a cycle in the cyclic etching process 206 comprises exposing the substrate to an etching plasma comprising an etching agent to etch a portion of the film within the gap. FIG. 3B schematically shows an etching plasma 314 formed over the substrate 302. FIG. 3B also schematically depicts an etching agent 316 adsorbed to the film 306. The etching plasma 314 forms reactive etching species from the etching agent.The reactive etching species react with and remove at least a portion of the film 306. The term “etching agent” is used herein to refer to both the etching agent prior to being converted to reactive etching species, and to the reactive etching species formed from the etching agent. As introduced above, in some examples, the etching agent 316 comprises a fluorine-containing etching agent. Some examples of fluorine-containing etching agents include molecular fluorine, hydrogen fluoride, nitrogen trifluoride, boron trifluoride, sulfur hexafluoride, and fluorocarbon compounds. In other examples, any other suitable etching agent can be used. Other examples of suitable etching agents include chlorine-based etching agents and other halogen-based etching agents.

[0080] The substrate 302 is exposed to the etching plasma under such conditions that the film 306 within the gap 304 is exposed to a higher concentration of etching agent 316 closer to an opening of the gap than the film 306 deeper within the gap. For example, FIG. 3B schematically depicts etching agent 316 species as small circles. In the example of FIG. 3B, the etching agent 316 is adsorbed to a surface of the film 306 with a higher concentration around the opening of the gap 304 than within the gap 304. This causes etching at a higher rate closer to the opening of the gap 304 compared to deeper within the gap 304. As a result, the sides of the film 306 within the gap 304 are tapered by the etching. Conditions of the etching plasma exposure can be varied to control a profile of the taper of the film 306 within the gap 304. For example, and as explained in more detail below, controlling a number of etching cycles can control an angle of taper of the film 306. Further, controlling a duration of etching plasma exposure in each etching cycle can control a depth within the gap to which the film is etched.

[0081] The etching plasma 314 can, in some examples, be formed with two or more different RF energy components. For example, the etching plasma 314 can be formed with a higher-frequency RF energy component and a lower-frequency RF energy component. In some such examples, the higher-frequency RF energy component comprises a frequency in a range of 10-100 MHz. The lower-frequency RF component can comprise a frequency in a range of 0-10 MHz. The RF power can additionally or alternatively control a depth within the recessed feature of the portion of the film that is etched. For example, addition of the lower-frequency RF component can be used to drive reactive etching species deeper within the gap 304 to etch the sides of a film being deposited in the gap more deeply. The addition of the lower-frequency RF component can additionally or alternatively cause sputtering of the film 306. Sputtering from thelower-frequency RF component can further be used to control a profile of a tapered portion of film 306.

[0082] Referring again to FIG. 2, after exposing the substrate to the etching plasma, the method 200 comprises purging the processing chamber, as indicated at 210. For example, the processing chamber can be purged by flowing an inert gas through the processing chamber for a sufficient time to remove at least some residual etching agent from the processing chamber. FIG. 3C shows the substrate 302 and the film 306 after purging a processing chamber in which the substrate 302 is located. As illustrated schematically in FIG. 3C, some amount of residual etching agent 316 can remain on the surface of the film 306 after purging. For example, FIG. 3C shows the residual etching agent 316 adsorbed to a surface of the film 306, including within the gap 304. Such residual etching agent 316 can cause prolonged etching and / or lead to a loss of control over the etching process.

[0083] Accordingly, the method 200 of FIG. 2 further comprises, at 212, exposing the substrate to a passivation plasma to remove residual etching agent from within the gap. The method 200 also includes, at 214, purging the processing chamber after exposing the substrate to the passivation plasma.

[0084] FIG. 3D shows an example of a passivation plasma 320. The passivation plasma 320 comprises reactive species that react with the residual etching agent 316 of FIG. 3C to remove the residual etching agent 316.

[0085] In some examples, the passivation plasma 320 comprises a reducing plasma, such as a hydrogen-containing plasma. The reducing plasma can reduce oxides or other etching agents. For example, hydrogen radicals in the reducing plasma can react with fluorine adsorbed to the film 306 within the gap to form volatile hydrogen fluoride. In this manner, at least some residual etching agent can be removed from the surface of the film 306. The reducing plasma additionally or alternatively can prime a surface of the film 306 for further processing. For example, the hydrogen-containing plasma can produce a surface of film 306 to which silicon-containing precursor can readily adsorb for a next deposition cycle.

[0086] The passivation plasma 320 can, in some examples, be formed with two or more different RF energy components. For example, the passivation plasma 320 can be formed with a higher-frequency RF energy component and a lower-frequency RF energy component. In some such examples, the higher-frequency RF energy component can comprise a frequency in a range of 10-100 MHz. The lower-frequency RFcomponent can comprise an RF frequency in a range of 0-10 MHz. Alternatively or additionally, addition of the lower-frequency RF component can cause sputtering of the film 306. Like the optional sputtering performed during step 208 of FIG. 2, the sputtering caused by the lower-frequency RF component can provide an additional measure of control over the profile of gap 304. Further, sputtering also can help remove residual etching species.

[0087] As indicated at 216, a plurality of etching cycles can be performed. As described in more detail below, a number of etching cycles can control an amount of material removed from the film, and thereby help to control an angle of taper.

[0088] FIG. 4 illustrates how different processing parameters can be adjusted to control an angle of taper of a gapfill film formed by a cyclic etching process. More particularly, FIG. 4 schematically illustrates another example of a substrate 402 and a film 406. As a first example controllable processing parameter that can be used to control a tapered profile, at 408, controlling a number of the etching cycles performed can control an angle of taper 410A, 410B of the film 406. For example, a first cyclic etching process can remove a first portion 412 of the film 406. Repeating the cyclic etching process can remove an additional portion 414 of the film. This results in widening of a top portion of the film 406 formed in a gap 416, as indicated by arrows 418A, 418B. In some examples, the cyclic etching process can comprise 100-1000 etching cycles. In some more specific examples, the cyclic etching process comprises 200-500 etching cycles. In further, more specific examples, the cyclic etching process comprises 250-350 etching cycles. It will also be appreciated, by one of ordinary skill in the art without undue experimentation, that steps 208-214 of FIG. 2 can be repeated any other suitable number of times. In other examples, a cyclic etching process can include less than 100 or more than 1000 etching cycles.

[0089] As a second example controllable processing parameter that can be used to control a tapered profile, controlling a duration of etching plasma exposure controls a depth within the gap of the portion of the film that is etched. For example, increasing the duration of the etching plasma exposure can allow reactive etching species to diffuse deeper into the gap 416 than at a shorter exposure duration. In this manner, increasing the duration of the etching plasma exposure results in deeper etching within the gap 416 (as indicated by arrow 422) relative to a shorter duration of etching plasma exposure. Likewise, reducing the duration of the etching plasma exposure prevents diffusion of the reactive etching species into the gap 416 relative to a longer duration of etching.

[0090] As a third example controllable processing parameter that can be used to control a tapered profile, controlling a flow rate of the etching agent can additionally or alternatively controls the etching depth within the gap. Similarly to the duration of the etching plasma exposure, increasing the flow rate of the etching agent can result in deeper etching within the gap relative to a smaller flow rate. In some examples, the flow rate of the etching agent is in a range of 10-1000 seem. In some more specific examples, the flow rate of the etching agent is in a range of 10-100 seem. In further more specific examples, the flow rate of the etching agent is in a range of 30-40 seem. This provides another measure of control over the etching process. In this manner, a suitable taper profile can be achieved by tuning the etching agent flow rate, the duration of the etching plasma exposure, and / or the number of etching cycles.

[0091] Referring again to FIG. 2, in some examples, the method 200 comprises, at 216, performing one or more additional deposition cycles 202 after the cyclic etching process. In some such examples, the method 200 further comprises performing another cyclic etching process after performing the one or more additional deposition cycles. In other examples, processing can terminate after the one or more additional deposition cycles. The controlled topology of the substrate surface achieved by an ALD process comprising a cyclic etching process as disclosed can allow gapfill to be performed while avoiding the formation of voids. Further, the disclosed examples can provide for a higher quality seam region in the gapfill than other gapfill methods

[0092] FIGS. 3E-3G schematically illustrate results of additional deposition cycles and, optionally, additional cyclic etching processes performed on the substrate 302 of FIGS. 3A-3D to complete a gapfill process. For example, as illustrated schematically in FIG. 3E, a first additional deposition process can increase a thickness 318 of the film 306. Similarly, the gap 304 is filled to a greater extent than in FIGS. 3A-3D, narrowing an internal width of the gap. Additional deposition fills the gap 304 further, as illustrated schematically in FIG. 3F. As illustrated by example in FIG. 3G, deposition with cyclical etching can fill the gap 304 without forming a poorer-quality seam region. Deposition can be performed by one or more separate deposition processes (e.g., ALD cycles) following or interspersed with one or more cyclic etching cycles. Without wishing to be bound by theory, forming proper taper profiles by the cyclical etching results in better-quality fill, because the taper helps a deposition plasma and / or deposition ions diffuse into the bottom of the gap and densify film during gapfill deposition.

[0093] FIGS. 5A-5B show a flow diagram depicting an example method 500 for filling a recessed feature on a substrate in a processing chamber. The following description of the method 500 is provided with reference to FIGS. 1-4 above and FIG. 6 below. It will be appreciated that the method 500 also can be performed in other contexts.

[0094] Referring first to FIG. 5A, at 502, the method 500 includes performing a deposition process comprising a plurality of deposition cycles to form a film within the recessed feature. For example, FIGS. 3 A-3D show an example of a film 306 formed by a plurality of ALD cycles. The film 306 is a conformal film that fills a portion of the gap 304.

[0095] In some examples, as indicated at 504, the recessed feature comprises an aspect ratio of 1 : 1 to 1 :300. For example, the gap 304 can have an aspect ratio in the range of 1 : 1 to 1 :50.

[0096] At 506, the method 500 further comprises shaping the film to form a tapered profile with respect to a depth of the film within the recessed feature during the deposition process by performing a cyclic etching process during the deposition process, the cyclic etching process comprising a plurality of etching cycles. As indicated at 508, FIG. 5A indicates that an etching cycle of the plurality of etching cycles comprises steps 510, 524, and 526. In some examples, the etching cycle additionally or alternatively includes one or more of steps 512, 514, 516, 518, 520, 522, 528, 530, 532, or 534.

[0097] At 510, the etching cycle includes exposing the substrate to an etching plasma comprising an etching agent to etch a portion of the film within the recessed feature. For example, FIG. 3B schematically shows an etching plasma 314 formed over the substrate 302. FIG. 3B also schematically depicts an etching agent 316 adsorbed to the film 306. The etching plasma generates reactive species that remove at least a portion of the film.

[0098] In some examples, at 512, etching the portion of the film comprises etching one or more of silicon oxide, silicon carbide, silicon oxy carbide, silicon nitride, silicon carbonitride, silicon oxycarbonitride, or silicon oxynitride.

[0099] At 514, in some examples, exposing the substrate to the etching plasma comprising the etching agent comprises exposing the substrate to a reactive halogen species in the etching plasma. In some examples, at 516, exposing the substrate to the reactive halogen species comprises exposing the substrate to a fluorine-containingspecies. Some examples of fluorine-containing etching agents include molecular fluorine, hydrogen fluoride, nitrogen trifluoride, boron trifluoride, sulfur hexafluoride, and fluorocarbon compounds. It will also be appreciated by one of ordinary skill in the art without undue experimentation that any other suitable etching agent can be used.

[0100] At 518, in some examples, exposing the substrate to the etching plasma comprises controlling a duration of etching plasma exposure to control a depth within the recessed feature of the portion of the film that is etched. For example, as illustrated schematically in FIG. 4, increasing the duration of the etching plasma exposure enables reactive etching species to diffuse deeper into the gap 416 than at a shorter exposure duration, and vice versa. This results in deeper etching within the gap 416 (as indicated by arrow 422) than that of a shorter plasma exposure.

[0101] In some examples, at 520, exposing the substrate to the etching plasma comprises controlling one or more of a flow rate of the etching agent or RF power of the etching plasma to control a depth within the recessed feature of the portion of the film that is etched. Similarly to the duration of the etching plasma exposure, increasing the flow rate of the etching agent results in deeper etching within the recessed feature relative to a smaller flow rate. Likewise, decreasing the flow rate of the etching agent results in shallower etching within the recessed feature relative to a greater flow rate.

[0102] At 522, in some examples, exposing the substrate to the etching plasma comprises exposing the substrate to a plasma with a higher-frequency radiofrequency energy component and a lower-frequency radiofrequency energy component. The combination of the higher-frequency radiofrequency energy component and the lower- frequency radiofrequency energy component provides suitable energy to generate reactive etching species and to cause some sputtering of the film. The sputtering can provide control over the taper profile.

[0103] Referring now to FIG. 5B, at 524, the method 500 comprises purging the processing chamber. This results in removing excess retching agent from the processing chamber. However, as illustrated schematically in FIG. 3C. some amount of residual etching agent 316 can remain on the surface of the film 306 after purging.

[0104] Accordingly, at 526, the method 500 comprises exposing the substrate to a passivation plasma to remove residual etching agent from within the recessed feature. The passivation plasma generates reactive species that react with and remove the residual etching agent (e.g., the residual etching agent 316 of FIG. 3C).

[0105] In some examples, at 528, exposing the substrate to the passivation plasma comprises exposing the substrate to a plasma with a higher-frequency radiofrequency energy component and a lower-frequency radiofrequency energy component. Like step 522, the combination of the higher-frequency radiofrequency energy component and the lower-frequency radiofrequency energy can cause some sputtering of the film. This provides another mechanism to control the taper profile.

[0106] At 530, in some examples, exposing the substrate to the passivation plasma comprises exposing the substrate to a reducing plasma. In some examples, at 532, exposing the substrate to the reducing plasma comprises exposing the substrate to a hydrogen-containing plasma. As described above, the reducing plasma can remove oxides or other etching agents from the surface of the film. The reducing plasma can additionally or alternatively prime the surface for additional deposition or etching.

[0107] At 534, in some examples, the method 500 comprises controlling a number of the etching cycles performed to control an angle of taper. For example, as illustrated schematically in FIG. 4, a first cyclic etching process can remove a first portion 412 of the film 406. Additional cyclic etching processes can remove additional portions of the film 406 to widen a top portion of the film 406 formed in the gap 416.

[0108] In some examples, at 536, the method 500 further comprises, after the cyclic etching process, performing one or more additional deposition cycles. For example, as indicated in FIG. 2, the deposition process 202 can be repeated any suitable number of times to achieve a desired film depth or shape. In this manner, the method 200 can be utilized for gapfill, as an example.

[0109] At 538, in some examples, the method 500 optionally further comprises performing another cyclic etching process after performing the one or more additional deposition cycles. For example, as indicated at 206 of FIG. 2, the cyclic etching process can be repeated after a suitable number of deposition cycles. This can shape an additional film formed by the additional deposition cycles. In this manner, the cyclic etching process enables fine control over the shape of the film.

[0110] The examples disclosed herein can allow a gap to be controllably filled in a bottom-up manner, without forming voids inside the gap, and can provide for a higher quality seam area than other ALD gapfill methods. A duration of the etching plasma exposure controls penetration depth of the etching agent into the gap. A number of etching cycles controls an amount of material removed from the film. By controlling these variables, etching depth and an amount of material removed from the film witheach etching cycle can be controlled independently. In addition, gapfill using a cyclic etching process during deposition according to the disclosed examples potentially can be performed with greater throughput than by using deposition-etch-deposition or deposition-sputter-deposition processes.[OHl] FIG. 6 schematically shows a non-limiting example of a computing system 600 that can enact one or more of the methods and processes described above. Computing system 600 is shown in simplified form. Computing system 600 may take the form of one or more personal computers, workstations, computers integrated with substrate processing tools, and / or network accessible server computers.

[0112] Computing system 600 includes a logic machine 602 and a storage machine 604 Computing system 600 may optionally include a display subsystem 606 input subsystem 608, communication subsystem 610, and / or other components not shown in FIG. 6. Controller 148 is an example of computing system 600.

[0113] Logic machine 602 includes one or more physical devices configured to execute instructions. For example, the logic machine may 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 may 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.

[0114] The logic machine may include one or more processors configured to execute software instructions. Additionally or alternatively, the logic machine may include one or more hardware or firmware logic machines configured to execute hardware or firmware instructions. Processors of the logic machine may be single-core or multi-core, and the instructions executed thereon may be configured for sequential, parallel, and / or distributed processing. Individual components of the logic machine optionally may be distributed among two or more separate devices, which may be remotely located and / or configured for coordinated processing. Aspects of the logic machine may be virtualized and executed by remotely accessible, networked computing devices configured in a cloud-computing configuration.

[0115] Storage machine 604 includes one or more physical devices configured to hold instructions 612 executable by the logic machine to implement the methods and processes described herein. When such methods and processes are implemented, the state of storage machine 604 may be transformed — e.g., to hold different data.

[0116] Storage machine 604 may include removable and / or built-in devices. Storage machine 604 may 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 machine 604 may include volatile, nonvolatile, dynamic, static, read / write, read-only, random-access, sequential-access, location-addressable, file- addressable, and / or content-addressable devices.

[0117] It will be appreciated that storage machine 604 includes one or more physical devices. However, aspects of the instructions described herein alternatively may 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.

[0118] Aspects of logic machine 602 and storage machine 604 may be integrated together into one or more hardware-logic components. Such hardware-logic components may 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.

[0119] When included, display subsystem 606 may be used to present a visual representation of data held by storage machine 604. This visual representation may 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 606 may likewise be transformed to visually represent changes in the underlying data. Display subsystem 606 may include one or more display devices utilizing virtually any type of technology. Such display devices may be combined with logic machine 602 and / or storage machine 604 in a shared enclosure, or such display devices may be peripheral display devices.

[0120] When included, input subsystem 608 may comprise or interface with one or more user-input devices such as a keyboard, mouse, or touch screen. In some examples, the input subsystem may comprise or interface with selected natural user input (NUI) componentry. Such componentry may be integrated or peripheral, and the transduction and / or processing of input actions may be handled on- or off- board. Example NUI componentry may 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.

[0121] When included, communication subsystem 610 may be configured to communicatively couple computing system 600 with one or more other computing devices. Communication subsystem 610 may include wired and / or wireless communication devices compatible with one or more different communication protocols. As non-limiting examples, the communication subsystem may 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 may allow computing system 600 to send and / or receive messages to and / or from other devices via a network such as the Internet.

[0122] “And / or” as used herein is defined as the inclusive or V, as specified by the following truth table:

[0123] The terminology “one or more of A or B” as used herein comprises A, B, or a combination of A and B. The terminology “one or more of A, B, or C” is equivalent to A, B, and / or C. As such, “one or more of A, B, or C” as used herein comprises A individually, B individually, C individually, a combination of A and B, a combination of A and C, a combination of B and C, or a combination of A, B and C.

[0124] 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 may represent one or more of any number of processing strategies. As such, various acts illustrated and / or described may be performed in the sequence illustrated and / or described, in other sequences, in parallel, or omitted. Likewise, the order of the above-described processes may be changed.

[0125] The subject matter of the present disclosure includes all novel and non- obvious combinations and sub-combinations of the various processes, systems andconfigurations, and other features, functions, acts, and / or properties disclosed herein, as well as any and all equivalents thereof.

Claims

CLAIMS:

1. A method for filling a recessed feature on a substrate in a processing chamber, the method comprising: performing a deposition process comprising a plurality of deposition cycles to form a film within the recessed feature; and shaping the film during the deposition process to form a tapered profile with respect to a depth of the film within the recessed feature by performing a cyclic etching process during the deposition process, the cyclic etching process comprising a plurality of etching cycles, wherein an etching cycle of the plurality of etching cycles comprises, exposing the substrate to an etching plasma comprising an etching agent to etch a portion of the film within the recessed feature; purging the processing chamber; and exposing the substrate to a passivation plasma to remove residual etching agent from within the recessed feature.

2. The method of claim 1, further comprising, after the cyclic etching process, performing one or more additional deposition cycles.

3. The method of claim 2, further comprising performing another cyclic etching process after performing the one or more additional deposition cycles.

4. The method of claim 1, wherein the recessed feature comprises an aspect ratio of 1 : 1 to 1 :300.

5. The method of claim 1, wherein exposing the substrate to the etching plasma comprises controlling a duration of etching plasma exposure to control a depth within the recessed feature of the portion of the film that is etched.

6. The method of claim 1, wherein exposing the substrate to the etching plasma comprises controlling one or more of a flow rate of the etching agent or radiofrequency power of the etching plasma to control a depth within the recessed feature of the portion of the film that is etched.

7. The method of claim 1, wherein shaping the film comprises controlling a number of the etching cycles performed to control an angle of taper.

8. The method of claim 1, wherein etching the portion of the film comprises etching one or more of silicon dioxide, silicon carbide, silicon oxycarbide, silicon nitride, silicon carbonitride, silicon oxycarbonitride, or silicon oxynitride.

9. The method of claim 1, wherein exposing the substrate to the etching plasma comprising the etching agent comprises exposing the substrate to a reactive halogen species in the etching plasma.

10. The method of claim 9, wherein exposing the substrate to the reactive halogen species comprises exposing the substrate to a fluorine-containing species.

11. The method of claim 1, wherein exposing the substrate to the etching plasma comprises exposing the substrate to a plasma with a higher-frequency radiofrequency energy component and a lower-frequency radiofrequency energy component.

12. The method of claim 1, wherein exposing the substrate to the passivation plasma comprises exposing the substrate to a plasma with a higher-frequency radiofrequency energy component and a lower-frequency radiofrequency energy component.

13. The method of claim 1 , wherein exposing the substrate to the passivation plasma comprises exposing the substrate to a reducing plasma.

14. The method of claim 13, wherein exposing the substrate to the reducing plasma comprises exposing the substrate to a hydrogen-containing plasma.

15. A processing tool, comprising: a processing chamber; a substrate support disposed in the processing chamber; flow control hardware configured to control flows of processing chemicals into the processing chamber;a radiofrequency (RF) power source operable to form a plasma in the processing chamber; and a controller configured to control the flow control hardware and the RF power source to fill a recessed feature on a substrate positioned on the substrate support within the processing chamber, wherein the controller is configured to, control the flow control hardware and the RF power source to perform a deposition process comprising a plurality of deposition cycles to form a film within the recessed feature; and control the flow control hardware and the RF power source to shape the film to form a tapered profile with respect to a depth of the film within the recessed feature during the deposition process by performing a cyclic etching process comprising a plurality of etching cycles during the deposition process, wherein the controller is further configured to control the flow control hardware and the RF power source to, during an etching cycle of the plurality of etching cycles, expose the substrate to an etching plasma comprising an etching agent to etch a portion of the film within the recessed feature; purge the processing chamber; and expose the substrate to a passivation plasma to remove residual etching agent from within the recessed feature.

16. The processing tool of claim 15, wherein the controller is further configured to control the flow control hardware and the RF power source to, after the cyclic etching process, perform one or more additional deposition cycles.

17. The processing tool of claim 15, wherein the etching agent comprises a reactive halogen species.

18. The processing tool of claim 17, wherein the reactive halogen species comprises a fluorine-containing species.

19. A method for filling a recessed feature on a substrate in a processing chamber, the method comprising:performing a deposition process comprising a plurality of deposition cycles to form a silicon oxide film within the recessed feature; and during the deposition process, shaping the silicon oxide film to form a tapered profile with respect to a depth of the silicon oxide film within the recessed feature by performing a cyclic etching process during the deposition process, the cyclic etching process comprising a plurality of etching cycles, wherein an etching cycle of the plurality of etching cycles comprises, exposing the substrate to an etching plasma comprising a fluorine- containing etching agent to etch a portion of the silicon oxide film within the recessed feature; purging the processing chamber; and exposing the substrate to a passivation plasma to remove residual fluorine-containing etching agent from within the recessed feature.

20. The method of claim 19, further comprising, after the cyclic etching process, performing one or more additional deposition cycles.

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