Reacting radical species with undeposited film precursor

Abstract

Examples are disclosed that relate to systems and methods for removing undeposited film precursors from a processing tool. One disclosed example provides a method of operating a processing tool. The method comprises introducing a precursor into a plasma in a processing chamber of the processing tool to deposit a film on a substrate in the processing chamber. While introducing the precursor into the plasma in the processing chamber, radical species formed in a remote plasma are introduced into a pumping path of the processing tool to react with undeposited precursor from the processing chamber.

Description

REACTING RADICAL SPECIES WITH UNDEPOSITED FILM PRECURSORBACKGROUND

[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] Examples are disclosed that relate to systems and methods for removing undeposited film precursors from a processing tool. One disclosed example provides a method of operating a processing tool. The method comprises introducing a precursor into a plasma in a processing chamber of the processing tool to deposit a film on a substrate in the processing chamber. While introducing the precursor into the plasma in the processing chamber, radical species formed in a remote plasma are introduced into a pumping path of the processing tool to react with undeposited precursor from the processing chamber.

[0004] In some such examples, the film precursor is additionally or alternatively a carbon-containing precursor.

[0005] In some such examples, the radical species formed in the remote plasma additionally or alternatively include hydrogen radicals.

[0006] In some such examples, the hydrogen radicals are additionally or alternatively generated by introducing one or more of hydrogen gas, hydrazine, or ammonia into the remote plasma.

[0007] In some such examples, the radical species formed in the remote plasma additionally or alternatively include oxygen-containing radicals.

[0008] In some such examples, the oxygen-containing radicals are additionally or alternatively generated by introducing one or more of oxygen, a nitrogen oxide, water vapor, hydrogen peroxide, or ozone into the remote plasma.

[0009] In some such examples, the radical species formed in the remote plasma are additionally or alternatively introduced into the pumping path in stoichiometric excess to the undeposited film precursor from the processing chamber.

[0010] In some such examples, the remote plasma is additionally or alternatively an inductively coupled plasma, and the plasma in the processing chamber is additionally or alternatively a capacitively coupled plasma.

[0011] In another example, a processing tool is presented. The processing tool comprises a processing chamber comprising an in-situ plasma generator. An exhaust system comprises a pump, a pumping path, and a throttle valve located along the pumping path between the processing chamber and the pump. A remote plasma injection system is configured to inject radical species into the pumping path, the remote plasma injection system comprising a remote plasma generator. A controller is configured to control the processing tool to introduce film precursor into a plasma in a processing chamber of the processing tool to deposit a film on a substrate in the processing chamber, and while introducing the film precursor into the plasma in the processing chamber, introduce radical species formed in the remote plasma generator into the pumping path, upstream of the throttle valve, of the processing tool to react with undeposited film precursor from the processing chamber.

[0012] In some such examples, the film precursor is additionally or alternatively a carbon-containing precursor.

[0013] In some such examples, the radical species additionally or alternatively include hydrogen radicals.

[0014] In some such examples, the controller is additionally or alternatively configured to control the processing tool to introduce one or more of hydrogen gas, hydrazine, or ammonia into the remote plasma generator to generate the hydrogen radicals.

[0015] In some such examples, the radical species formed in the remote plasma additionally or alternatively include oxygen-containing radicals.

[0016] In some such examples, the controller is additionally or alternatively configured to control the processing tool to introduce one or more of oxygen, a nitrogen oxide, water vapor, hydrogen peroxide, or ozone into the remote plasma generator to generate the oxygen-containing radicals.

[0017] In some such examples, the controller is additionally or alternatively configured to control the processing tool to introduce the radical species formed in the remote plasma into the pumping path in stoichiometric excess to the undeposited precursor from the processing chamber.

[0018] In some such examples, the remote plasma generator is additionally or alternatively an inductively coupled plasma generator, and the in-situ plasma generator is additionally or alternatively a capacitively coupled plasma generator.

[0019] In another example, a storage machine is presented. The storage machine holds instructions executable by a logic machine to introduce film precursor into a plasma in a processing chamber of a processing tool to deposit a film on a substrate in the processing chamber; and while introducing the film precursor into the plasma in the processing chamber, introduce radical species formed in a remote plasma generator into a pumping path of the processing tool to react with undeposited film precursor from the processing chamber.

[0020] In some such examples, controller is further configured to control the processing tool to introduce one or more of hydrogen gas, hydrazine, or ammonia into the remote plasma generator to generate hydrogen radicals.

[0021] In some such examples, controller is further configured to control the processing tool to introduce one or more of oxygen, a nitrogen oxide, water vapor, hydrogen peroxide, or ozone into the remote plasma generator to generate oxygencontaining radicals.

[0022] In some such examples, controller is further configured to control the processing tool to introduce the radical species formed in the remote plasma into the pumping path in stoichiometric excess to the undeposited precursor from the processing chamber.BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 shows a block diagram of an example processing tool configured to introduce radical species into a pumping path of the processing tool to deactivate undeposited precursors.

[0024] FIG. 2 shows a flow chart illustrating an example method of operating a processing tool to deactivate undeposited precursors.

[0025] FIG. 3 schematically shows a pumping path of the example processing tool of FIG. 1.

[0026] FIG. 4 schematically shows an example computing system.DETAILED DESCRIPTION

[0027] The term “carbon-containing precursor” generally represents a compound that includes one or more carbon atoms for forming a carbon-containing thin film.

[0028] The term “film” generally represents a layer of material deposited on a substrate.

[0029] The term “film precursor” generally represents any material that can be introduced into a processing chamber to form an oxide film on a substrate disposed within the processing chamber. Examples of film precursors include silicon-containing precursors that can be used to form silicon-containing films such as silicon dioxide, silicon oxynitride, and silicon oxycarbide films. Other examples of film precursors include metal-containing precursors for forming metal oxide films. Examples of such metal-containing precursors include aluminum-containing precursors, hafnium- containing precursors, titanium-containing precursors, tungsten-containing precursors, tin-containing precursors, and molybdenum-containing precursors, which respectively may be used to form aluminum oxide (AI2O3), hafnium oxide (HfOx), titanium oxide (TiOx), tungsten oxide (WOx), tin oxide (SnOx), and molybdenum oxide (MoOx) films.

[0030] The term “plasma” generally represents a gas comprising cations and free electrons. A plasma may be used to generate reactive chemical species from a precursor molecule introduced into the plasma. The term “in-situ plasma” may generally represent a plasma to which a substrate is directly exposed during a process. The term “remote plasma” may generally represent a plasma that is located remote from a substrate being processed. The term “capacitively coupled plasma” generally represents a plasma generated between two electrodes. The term “inductively coupledplasma” generally represents a plasma generated by electric currents which are produced by electromagnetic induction.

[0031] The term “plasma generator” generally represents a device configured to generate a plasma to provide reactive species and / or energetic ions for substrate processing in a processing chamber.

[0032] The term “processing chamber” generally represents an enclosure in which chemical and / or physical processes are performed on substrates. The pressure, temperature and atmospheric composition within a processing chamber are controllable to perform chemical and / or physical processes.

[0033] 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.

[0034] The term “pumping path” generally represents an exhaust pathway for a processing tool that is driven by one or more pumps.

[0035] The term “radical species” generally represents a chemical species that includes an unpaired electron. The term “hydrogen radicals” generally represents a hydrogen atom that includes an unpaired electron. The term “oxygen-containing radicals” generally represents a compound that includes one or more oxygen atoms that includes an unpaired electron.

[0036] The term “showerhead” generally represents a processing chemical outlet comprising a plurality of holes distributed across an area for introducing processing chemicals into the processing chamber.

[0037] The term “secondary purge gas outlet generally represents a device configured to form secondary purge gas flow around the outside edge of the showerhead.

[0038] The term “substrate” generally represents any object on which a film can be deposited.

[0039] Plasma-enhanced chemical vapor deposition (PECVD) utilizes a plasma to generate reactive species from film precursors that are introduced into the plasma. When film precursor molecules are introduced into the plasma, the energetic ions in the plasma form reactive species from the film precursor molecules. The reactive species then can deposit as a film on a substrate.

[0040] In some PECVD processes, the plasma can be an in-situ plasma formed in a processing chamber of a PECVD tool (e.g. between showerhead and substrateholder electrodes). Other PECVD processes can use a remote plasma to generate reactive species for film deposition, as opposed to an in-situ plasma. A remote plasma is a plasma that is formed at a location remote from, but fluidically connected with, a location in a processing chamber at which a substrate is being processed. Radicals from the remote plasma diffuse to the substrate to deposit at as a film. An in-situ plasma or a remote plasma each can be either capacitively coupled or inductively coupled in various examples.

[0041] In some PECVD processes, radical polymerization of undeposited precursor can occur within a pumping path of a PECVD tool. The undeposited precursor can take the form of activated precursor radicals, or unactivated precursor molecules. As a more specific example, in a carbon PECVD tool, acetylene (C2H2) can be used as a carbon film precursor. To deposit a carbon film, the acetylene can be activated in a plasma to form carbon-containing radical species such as *C2H, as well as hydrogen radicals (*H). The carbon-containing radicals can react to form a carbon film (for example, amorphous carbon) on a substrate.

[0042] However, not all carbon-containing radicals that are generated deposit on the substrate. Further, not all acetylene precursor molecules are activated in the plasma. The hydrogen radicals and undeposited carbon-containing radicals can initiate radical polymerization of undeposited acetylene precursor in the exhaust stream from the processing chamber. As a result, polymer materials formed by the radical polymerization can form deposits within the pumping path. Such deposits can be difficult to remove. Over time, the polymer materials may interfere with the function of components of the processing tool, such as a throttle valve in the pumping path. Further, the cleaning of the exhaust system results in PECVD tool downtime, and thereby can increase operational costs. Current methods of avoiding such deposits of polymer materials include restricting a process window for the deposition process in a manner determined to result in lesser amounts of deposits. However, this may reduce flexibility in process design.

[0043] Accordingly, examples are disclosed that relate to the introduction of radical species into the pumping path during a film deposition process to chemically deactivate undeposited precursor. The radical species may be introduced while the precursor is being introduced into the processing chamber for film deposition. This can help prevent the undeposited precursor from forming polymer deposits within thepumping path. Further, polymer deposits may be etched and removed from the pumping path by the introduced radical species.

[0044] FIG. 1 shows a schematic depiction of an example processing tool 100 configured to perform PECVD. The processing tool 100 is configured for the deposition of carbon films. The processing tool 100 comprises a processing chamber 102 and a substrate holder 104 within the processing chamber. The substrate holder 104 is configured to support a substrate 106 disposed within processing chamber 102. The substrate holder 104 comprises a substrate heater 108. In other examples, a heater can be omitted, or can be located elsewhere within processing chamber 102. The processing tool 100 further comprises a showerhead 110 for introducing processing chemicals into the processing chamber. In some examples, the processing tool 100 comprises a heater configured to heat showerhead 110.

[0045] The processing tool 100 further comprises an optional secondary purge gas outlet 111. Secondary purge gas outlet 111 is configured to form secondary purge gas flow around the outside edge of showerhead 110.

[0046] The processing tool 100 further comprises flow control hardware 112. The flow control hardware 112 connects processing chemical source(s) to the processing chamber. In the depicted example, the flow control hardware 112 connects a film precursor source 116, an etchant source 118, and an inert gas source 122 to the processing chamber. The flow control hardware 112 can include any suitable components. For example, the flow control hardware 112 can comprise one or more valves controllable to place a selected gas source or selected gas sources in fluid connection with showerhead 110. The flow control hardware 112 also can comprise one or more mass flow controllers or other controllers for controlling a mass flow rate of gas.

[0047] Film precursor source 116 comprises any suitable precursor compound for forming a film on substrate 106. In some examples, film precursor source 116 is a carbon-containing precursor source. Such a carbon-containing precursor source may comprise 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 CnEkn 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-containingfilm precursors comprise cyclic aliphatic hydrocarbons, aromatic hydrocarbons, heterocyclic compounds, and alkyl amines. In other examples, film precursor source 116 may include silicon-containing precursors that can be used to form silicon- containing films such as silicon dioxide, silicon oxynitride, and silicon oxycarbide films. Other examples of film precursors include metal-containing precursors for forming metal oxide films.

[0048] In some examples, an etchant source 118 is included to introduce an etchant into a precursor gas mix for depositing a carbon film. Etchants can facilitate carbon film deposition. Example etchants can include one or more of hydrogen (Eb), ammonia (NEE), 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).

[0049] The inert gas source 122 comprises any suitable inert gas. Examples include argon, helium, neon, krypton, and xenon, as well as nitrogen in some processing environments.

[0050] The processing tool 100 further comprises an exhaust system 132. The exhaust system 132 is configured to exhaust gases from the processing chamber 102. The exhaust system 132 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, such as a throttle valve 133. Together, flow control hardware 112 and exhaust system 132 can be operated to achieve a selected pressure in processing chamber 102 during substrate processing. Example pressures include pressures of 1 Torr to 50 Torr. In more specific examples, the pressure in the processing chamber can be within a range of 1-20 Torr. In other examples, the pressure in the processing chamber can be within a range of 1-10 Torr, within a range of 10-20 Torr, within a range of 20-30 Torr, within a range of 30-40 Torr, or within a range of 40-50 Torr. Further, exhaust system 132 can be operated to purge processing chamber 102.

[0051] The processing tool 100 further comprises an RF power source 134 configured to form a RF plasma in processing chamber 102. The RF power source 134 can supply RF power to the showerhead electrode or substrate holder electrode in various examples. As shown in FIG. 1, the RF power is provided to substrate holder 104, and showerhead 110 is configured as a grounded opposing electrode. In other examples, the RF power source 134 can supply RF power to showerhead 110, and substrate holder 104 can be grounded. In the depicted example, a capacitively coupled plasma can be formed in processing chamber 102 between showerhead 110 and substrate holder 104. In other examples, an inductively coupled plasma can be used. In further examples, a remote plasma can be used to generate radical species for film deposition. The processing tool 100 further includes a matching network 136 for impedance matching of the RF power source 134.

[0052] In some examples, the radiofrequency power source 134 is configured to provide RF power comprising a lower-frequency (LF) RF power 134A and a higher- frequency (HF) RF power 134B 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 134 is configured to supply a single frequency (e.g. HF) of RF power.

[0053] The processing tool 100 further comprises a controller 150 configured to control operation of the processing tool. The controller 150 is operatively coupled to the substrate heater 108, the flow control hardware 112, the exhaust system 132, and the RF power source 134. The controller 150 is configured to control various functions of processing tool 100 to perform PECVD.

[0054] The processing tool 100 further comprises a remote plasma generator 160 to generate radical species for deactivating undeposited precursors in an exhaust stream from processing chamber 102. The remote plasma generator can be configured to generate any suitable radical species, including hydrogen radicals and / or oxygencontaining radicals, as described above. The remote plasma generator 160 receives gas from a remote plasma gas source 162. Example gases that can be used by remote plasma generator 160 to form radicals include hydrogen-containing molecules such as molecular hydrogen (H2), ammonia (NH3), and hydrazine (N2H2). Examples also include oxygen-containing molecules such as molecular oxygen (O2), water vapor(H2O), ozone (O3), hydrogen peroxide (H2O2), or a nitrogen oxide (e.g. nitrous oxide (N2O)).

[0055] In some examples, the remote plasma generator 160 can be configured to introduce radical species into the pumping path downstream of the processing chamber 102 and upstream of the throttle valve 133, as indicated at 164. The term “pumping path” generally refers to the path from a gas inlet in the processing chamber 102 through the exhaust system 132. In other examples, the remote plasma generator can be configured to introduce radical species into the secondary purge gas flow, such that the radical species flow into the processing chamber 102 through the secondary purge gas outlet 111, as indicated at 166.

[0056] FIG. 2 shows a flow chart for an example method 200 for operating a processing tool, such as processing tool 100. At 210, method 200 includes introducing film precursor into a plasma in a processing chamber of the processing tool to deposit a film on a substrate in the processing chamber. For example, the film precursor may be a carbon-containing precursor. While the disclosed examples are described using acetylene as a carbon-containing precursor, other suitable carbon-containing precursors can be used in other examples. 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.

[0057] At 220, method 200 includes, while introducing the film precursor into the plasma in the processing chamber, introducing radical species formed in a remote plasma generator into a pumping path of the processing tool to react with undeposited film precursor from the processing chamber. A PECVD tool can include a remote plasma generator to generate radical species for introduction into a pumping path of a PECVD tool. The remote plasma generator can use a capacitively coupled plasma or an inductively coupled plasma to generate radical species for deactivating the undeposited precursors in the exhaust stream. The radical species introduced into the pumping path can react with undeposited precursor radicals to thereby form chemicalbonds, extinguishing the undeposited precursor radicals. The product of the reactions may be less reactive than the undeposited precursor radicals, thereby reducing the rate of polymer production within the pumping path.

[0058] Any suitable radical species can be generated in the remote plasma for introduction into the pumping path. In some examples, hydrogen radicals are generated. The hydrogen radicals can react with undeposited precursor radicals to form neutral, non-radical molecules. As a more specific example, *C2H radicals can react with hydrogen radicals to form acetylene. While acetylene is a reactive molecule, neutral acetylene may be less prone to polymerization than *C2H radicals. Thus, reacting *C2H radicals with hydrogen radicals can reduce a rate of polymer formation within the pumping path of the PECVD tool. Hydrogen radicals can be formed, for example, by introducing hydrogen-containing molecules into the remote plasma. Examples of the hydrogen-containing molecules include molecular hydrogen (H2), ammonia (NH3), and hydrazine (N2H2).

[0059] In other examples, oxygen-containing radical species can be generated in the remote plasma to oxidize undeposited precursor. For example, an oxygencontaining molecule such as molecular oxygen (O2), water vapor (H2O), ozone (O3), hydrogen peroxide (H2O2), carbon dioxide (CO2), or a nitrogen oxide (e.g. nitrous oxide (N2O)) can be introduced into the remote plasma. Oxygen-containing radical species can react with undeposited precursor in the exhaust stream to oxidize the undeposited precursor. Where the undeposited precursor is a carbon-containing precursor (e.g. acetylene and acetylene-derived radicals), oxidation of the carbon-containing precursor by the oxygen-containing radical species can generate carbon oxides (e.g. carbon monoxide and / or carbon dioxide) and water from the undeposited precursor, thereby reducing polymerization of the undeposited precursor.

[0060] In some examples, a concentration of radical species introduced into the pumping path is in stoichiometric excess compared to the undeposited precursor. This may help to avoid the radical species introduced into the pumping path from initiating radical polymerization of the undeposited precursor. For example, excess hydrogen radicals can react with undeposited precursor to form molecules that are less prone to radical polymerization, thereby reducing the initiation of radical polymerization. As a more specific example, C2H2 can react with hydrogen radicals to form less reactive molecules, such as C3H6 (ethylene) or CH4 (methane). The excess radical species also can help to remove previously formed polymer deposits from the pumping path.

[0061] The radical species can be introduced into the pumping path at any suitable location. In some examples, the radical species are introduced into an exhaust line of the exhaust system, downstream of the processing chamber. In such examples, the radical species can be introduced into the exhaust line at a location upstream of a valve (e.g. a throttle valve) of the exhaust system. In other examples, the radical species can be introduced into the pumping path at another suitable location, such as into a secondary purge gas flow. A secondary purge gas flow is a flow of gas in the form of a curtain at a perimeter of a showerhead. Introducing radical species into the secondary purge gas flow can provide for the deactivation of at least some undeposited precursor at a location along the pumping path upstream of the exhaust line. This further may help to avoid polymer accumulation within the pumping path.

[0062] As an example, FIG. 3 depicts aspects of processing tool 100 with film precursor (D) and radical species (R) illustrated within the processing tool. Film precursor (D) is introduced to processing chamber 102 via flow control hardware 112. Therein, an in-situ plasma generator (e.g., CCP) generates radicals (D») and ions that may polymerize and deposit on substrate 106 or elsewhere in processing tool 100 outside of processing chamber 102. For example, processing tool 100 comprises an exhaust system 132. Exhaust system 132 comprises a pump 300 and a pumping path 302 extending from processing chamber 102. Throttle valve 133 is located along pumping path 302 between processing chamber 102 and pump 300. Radical polymerization occurs as gas flows to throttle valve 133. At throttle valve 133, there can be a mix of polymer (Dx) and unreacted radicals (D»). Polymer (Dx) built up in pumping path302 may be difficult to clean, resulting in processing tool downtime. It is desirable to clean up such polymer without increasing the radical activation of the film precursor species while at the same time preventing further interactions between radical species and neutral species.

[0063] A remote plasma gas source 162 and a remote plasma generator are comprised in a remote plasma injection system configured to generate and inject radical species (R») into pumping path 302 (via 164). Upwards of 90% of the radical precursors may be cracked at remote plasma generator 160. In some examples, remote plasma generator may additionally or alternatively inject radical species into secondary purge gas outlet 111 (via 166). In some such examples, the size of showerhead 110 may be increased relative to substrate 106 to prevent against non-uniformity at substrate edges.

[0064] Interactions between film precursor radicals (D») and neutral depositor species (D) can result in time-dependent polymer formation (Dx, Dx»). For example, acetylene is highly reactive and may spontaneously polymerize into multiple types of poly-hydrocarbon species. Up to 90% or more of the introduced film precursor (D) is unreacted or partially reacted. Thus, radicals are formed but don’t get deposited onto the substrate surface. These radicals may initiate a radical polymerization chain reaction generating large polymers that are still chemically reactive (Dx»). Remote plasma generated radical species (R») can be used to neutralize the film precursor radicals and neutral depositor species as well as to etch already deposited polymers (-Dx).

[0065] For example, at 310, precursor radicals (D») are shown reacting with radical species (R») in a deactivating radical chain reaction to generate dead end reactants (DR). Similarly, at 312, radical polymers (Dx») are shown reacting with radical species (R») in a deactivating radical chain reaction to generate dead end reactants (DxR).

[0066] At 314, neutral depositor species (D) are shown reacting with one or more radical species (X[R»]) to generate a lower reactivity product dRx, where the reactivity of d is «< than that of D. For example, acetylene may be reacted with hydrogen radicals to form ethylene and / or methane.

[0067] At 316, deposited polymer (-Dx) within pumping path 302 is shown reacting with radical species (R»), thereby etching the polymer off of the pumping path walls. The etched species are flowed towards pump 300.

[0068] Thus, the disclosed examples can provide for a wider process window than where the introduction of radical species into the pumping path is not used. The disclosed examples also can help to reduce buildup in sensitive locations of the pumping path (e.g. at a throttle valve) and prevent further polymerization from building up further downstream.

[0069] FIG. 4 schematically shows a non-limiting example of a computing system 400 that can enact one or more of the methods and processes described above. Computing system 400 is shown in simplified form. Computing system 400 may take the form of one or more personal computers, workstations, computers integrated with substrate processing tools, and / or network accessible server computers.

[0070] Computing system 400 includes a logic machine 402 and a storage machine 404. Computing system 400 may optionally include a display subsystem 406,input subsystem 408, communication subsystem 410, and / or other components not shown in FIG. 4. Controller 150 is an example of computing system 400.

[0071] Logic machine 402 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.

[0072] 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.

[0073] Storage machine 404 includes one or more physical devices configured to hold instructions 412 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 404 may be transformed — e.g., to hold different data.

[0074] Storage machine 404 may include removable and / or built-in devices. Storage machine 404 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 404 may include volatile, nonvolatile, dynamic, static, read / write, read-only, random-access, sequential-access, location-addressable, file- addressable, and / or content-addressable devices.

[0075] It will be appreciated that storage machine 404 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.

[0076] Aspects of logic machine 402 and storage machine 404 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.

[0077] When included, display subsystem 406 may be used to present a visual representation of data held by storage machine 404. 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 406 may likewise be transformed to visually represent changes in the underlying data. Display subsystem 406 may include one or more display devices utilizing virtually any type of technology. Such display devices may be combined with logic machine 402 and / or storage machine 404 in a shared enclosure, or such display devices may be peripheral display devices.

[0078] When included, input subsystem 408 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.

[0079] When included, communication subsystem 410 may be configured to communicatively couple computing system 400 with one or more other computing devices. Communication subsystem 410 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 400 to send and / or receive messages to and / or from other devices via a network such as the Internet.

[0080] It will be understood that the configurations and / or approaches described herein are exemplary in nature, and that these specific examples or examplesare 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.

[0081] The subject matter of the present disclosure includes all novel and non- obvious combinations and sub-combinations of the various processes, systems and configurations, and other features, functions, acts, and / or properties disclosed herein, as well as any and all equivalents thereof.

Claims

CLAIMS:

1. A method of operating a processing tool, the method comprising: introducing film precursor into a plasma in a processing chamber of the processing tool to deposit a film on a substrate in the processing chamber; and while introducing the film precursor into the plasma in the processing chamber, introducing radical species formed in a remote plasma generator into a pumping path of the processing tool to react with undeposited film precursor from the processing chamber.

2. The method of claim 1, wherein the film precursor is a carbon- containing precursor.

3. The method of claim 2, wherein the radical species formed in the remote plasma include hydrogen radicals.

4. The method of claim 3, wherein the hydrogen radicals are generated by introducing one or more of hydrogen gas, hydrazine, or ammonia into the remote plasma.

5. The method of claim 2, wherein the radical species formed in the remote plasma include oxygen-containing radicals.

6. The method of claim 5, wherein the oxygen-containing radicals are generated by introducing one or more of oxygen, a nitrogen oxide, water vapor, hydrogen peroxide, or ozone into the remote plasma.

7. The method of claim 1, wherein the radical species formed in the remote plasma are introduced into the pumping path in stoichiometric excess to the undeposited film precursor from the processing chamber.

8. The method of claim 1, wherein the remote plasma is an inductively coupled plasma, and wherein the plasma in the processing chamber is a capacitively coupled plasma.

9. A processing tool, comprising: a processing chamber comprising an in-situ plasma generator; an exhaust system comprising: a pump, a pumping path, and a throttle valve located along the pumping path between the processing chamber and the pump; a remote plasma injection system configured to inject radical species into the pumping path, the remote plasma injection system comprising a remote plasma generator; and a controller configured to control the processing tool to introduce film precursor into a plasma in the processing chamber of the processing tool to deposit a film on a substrate in the processing chamber; and while introducing the film precursor into the plasma in the processing chamber, introduce radical species formed in the remote plasma generator into the pumping path, upstream of the throttle valve, of the processing tool to react with undeposited film precursor from the processing chamber.

10. The processing tool of claim 9, wherein the film precursor is a carbon- containing precursor.

11. The processing tool of claim 9, wherein the radical species include hydrogen radicals.

12. The processing tool of claim 11, wherein the controller is configured to control the processing tool to introduce one or more of hydrogen gas, hydrazine, or ammonia into the remote plasma generator to generate the hydrogen radicals.

13. The processing tool of claim 9, wherein the radical species formed in the remote plasma include oxygen-containing radicals.

14. The processing tool of claim 13, wherein the controller is configured to control the processing tool to introduce one or more of oxygen, a nitrogen oxide, watervapor, hydrogen peroxide, or ozone into the remote plasma generator to generate the oxygen-containing radicals.

15. The processing tool of claim 9, wherein the controller is configured to control the processing tool to introduce the radical species formed in the remote plasma into the pumping path in stoichiometric excess to the undeposited precursor from the processing chamber.

16. The processing tool of claim 9, wherein the remote plasma generator is an inductively coupled plasma generator, and wherein the in-situ plasma generator is a capacitively coupled plasma generator.

17. A processing tool, comprising: a processing chamber comprising an in-situ plasma generator; a showerhead located within the processing chamber; a secondary purge gas outlet configured to form secondary purge gas flow around an outside of the showerhead; an exhaust system; a remote plasma injection system configured to inject radical species into the secondary purge gas outlet, the remote plasma injection system comprising a remote plasma generator; and a controller configured to control the processing tool to introduce film precursor into a plasma in the processing chamber of the processing tool to deposit a film on a substrate in the processing chamber; and while introducing the film precursor into the plasma in the processing chamber, introduce radical species formed in the remote plasma generator into the secondary purge gas outlet to react with undeposited film precursor from the processing chamber.

18. The processing tool of claim 17, wherein the controller is further configured to control the processing tool to: introduce one or more of hydrogen gas, hydrazine, or ammonia into the remote plasma generator to generate hydrogen radicals.

19. The processing tool of claim 17, wherein the controller is further configured to control the processing tool to: introduce one or more of oxygen, a nitrogen oxide, water vapor, hydrogen peroxide, or ozone into the remote plasma generator to generate oxygen-containing radicals.

20. The processing tool of claim 17, wherein the controller is further configured to control the processing tool to: introduce the radical species formed in the remote plasma into the secondary purge gas outlet in stoichiometric excess to the undeposited precursor from the processing chamber.

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