Selective carbon removal treatment process using metastable activated radical species

Abstract

A method for etching substrates using a metastable activated radical species is provided, the method including providing a substrate having a target material deposited thereon to a process chamber having a processing region, generating radicals of an inert gas in a remote plasma generator, introducing the radicals to the processing region, introducing an etching gas downstream of the remote plasma generator, wherein the etching gas reacts with the radicals in the processing region to form an etching species, and exposing the target material to the etching species in the processing region.

Description

SELECTIVE CARBON REMOVAL TREATMENT PROCESS USING METASTABLE ACTIVATED RADICAL SPECIESCROSS-REFERENCES

[0001] A PCT Request Form is filed concurrently with this specification as part of the present application. Each application that the present application claims benefit of or priority to as identified in the concurrently filed PCT Request Form is incorporated by reference herein in their entireties and for all purposes.BACKGROUND

[0002] Semiconductor fabrication processes often involve etching features on the substrate. For example, in some cases, contact holes are formed on a substrate using a patterned hard mask. However, as devices shrink, it is challenging to etch high aspect ratio features using certain methods.

[0003] The background description provided herein is for the purposes of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.SUMMARY

[0004] One aspect involves a method for processing substrates, the method including: providing a substrate having a target material deposited thereon to a process chamber having a processing region; generating radicals of an inert gas in a remote plasma generator; introducing the radicals to the processing region; introducing an etching gas downstream of the remote plasma generator, whereby the etching gas reacts with the radicals in the processing region to form an etching species; and exposing the target material to the etching species in the processing region.

[0005] In various embodiments, the etching gas is delivered through a manifold positioned between the processing region and the remote plasma generator.

[0006] In various embodiments, the etching species includes metastable activated radical species.

[0007] In various embodiments, the remote plasma generator is an inductively coupled plasma generator.

[0008] In various embodiments, the remote plasma generator is dome-shaped.

[0009] In various embodiments, penning ionization occurs in the processing region to react theradicals with the etching gas.

[0010] In various embodiments, the etching gas includes methane.

[0011] In various embodiments, the etching species is selected from the group consisting of hydrogen radicals, CH3* radicals, and CxHy* radicals.

[0012] In various embodiments, the etching species includes radicals.

[0013] In various embodiments, the inert gas is selected from a group consisting of hydrogen gas, argon gas, and combinations thereof.

[0014] In various embodiments, the substrate further includes a low-k dielectric material.

[0015] In various embodiments, the substrate further includes one or more layers having materials selected from the group consisting of silicon oxide, silicon nitride, poly-silicon, and amorphous silicon.

[0016] In various embodiments, etching is performed until a metal or metal nitride material is exposed.

[0017] In various embodiments, the target material is a photoresist material.

[0018] In various embodiments, the target material is a carbon, hydrogen, and fluorine- containing material.

[0019] In various embodiments, the target material is etched selective to a second material. In some embodiments, the second material is silicon oxide or low-k dielectric material.

[0020] In various embodiments, the process chamber is set to a chamber pressure of about 700 mTorr to about 4000 mTorr.

[0021] In various embodiments, the substrate is provided on a pedestal, and a gap between the pedestal and manifold is about 1 inch to about 1.25 inches.

[0022] Another aspect involves a method for processing substrates, the method including: providing a substrate having a target material deposited thereon to a process chamber having a remote plasma generator and a lower chamber, whereby a manifold separates the remote plasma generator and the lower chamber; flowing an inert gas to a remote plasma generator, whereby the inert gas is selected from the group consisting of hydrogen, argon, and mixtures thereof; generating radicals in the remote plasma generator; delivering radicals from the remote plasma generator to the lower chamber; flowing methane gas directly to the manifold, such that the manifold distributes methane gas to the lower chamber; reacting methane gas with the radicals to generate a metastable activated radical species; and etching the target material with the metastable activated radical species.

[0023] Another aspect involves an apparatus for processing substrates, the apparatusincluding: a process chamber including a manifold dividing the process chamber into an upper chamber and a lower chamber; a movable pedestal in the lower chamber; a remote inductively- coupled plasma generator in the upper chamber; one or more gas inlets for delivering a first gas into the upper chamber and a first associated flow-control hardware; a gas source for delivering a second gas to the manifold without delivering the second gas to the upper chamber; one or more gas inlets for delivering a second gas into the manifold and a second associated flow-control hardware; and a controller having at least one processor and a memory, whereby the at least one processor and the memory' are communicatively connected with one another, the at least one processor is at least operatively connected with the first and second flow-control hardware, and the memory stores computer-executable instructions for controlling the at least one processor to at least control the flow-control hardware to: cause generation of radicals in the upper chamber; cause introduction of the radicals from the upper chamber to the lower chamber; cause introduction of the second gas via the manifold to the lower chamber; cause generation of metastable species in the lower chamber; and cause etching of a material on a substrate on the pedestal using the metastable species.

[0024] In various embodiments, the manifold and movable pedestal are separated by a gap having a distance of about 1 inch to about 1.25 inches.

[0025] In various embodiments, the manifold includes two or more sets of holes, at least one set for delivering species from the upper chamber to the lower chamber, and at least one set for deliver species from the gas source to the lower chamber without delivering the species into the upper chamber.

[0026] These and other aspects are described further below with reference to the drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a process flow diagram depicting operations for a method performed in accordance with certain disclosed embodiments.

[0028] Figures 2A-2D are schematic illustrations of example substrates undergoing certain operations.

[0029] Figure 3A is a schematic illustration of an example of a section of a substrate processing station in accordance with certain disclosed embodiments.

[0030] Figure 3B is a schematic illustration of an example of a top view of a section of a manifold in accordance with certain disclosed embodiments.

[0031] Figure 4 is a functional block diagram of an example of a substrate processing system including a showerhead or manifold in accordance with certain disclosed embodiments.

[0032] Figure 5 is a plan view of an example of the showerhead in accordance with certain disclosed embodiments.DETAILED DESCRIPTION

[0033] In the following description, numerous specific details are set forth to provide a thorough understanding of the presented embodiments. The disclosed embodiments may be practiced without some or all of these specific details. In other instances, well-known process operations have not been described in detail to not unnecessarily obscure the disclosed embodiments. While the disclosed embodiments will be described in conjunction with the specific embodiments, it will be understood that it is not intended to limit the disclosed embodiments.

[0034] Semiconductor fabrication processes may involve etching a substrate to form features such as trenches or vias. “Features’" such as via or contact holes may be characterized by one or more of narrow and / or re-entrant openings, constrictions within the feature, and high aspect ratios. The term “feature” as described herein refers to negative features such as holes or vias. Etching features, in many cases, involves depositing and patterning a hard mask over the material to be etched, and etching the material using the hard mask as a pattern. The patterned hard mask may eventually be removed from the substrate.

[0035] As devices shrink, aspect ratios of these features increase, which causes etching of high aspect ratio negative features to be very challenging while maintaining a hole diameter at the top of the hole consistent with the hole diameter at the bottom of the feature. Etching may be performed to achieve very small feature sizes as well. Certain small features may have a small feature opening. Example feature openings may be less than about 10 nm or less than about 5 nm in diameter. Certain small features may have a high aspect ratio. High aspect ratio as described herein refers to aspect ratios greater than 20: 1, such as between 50: 1 and 60: 1. It may be challenging to etch certain materials without substantially damaging other exposed materials. It may also be challenging to etch certain materials without causing redeposition of material onto the substrate, which might cause defects or other problems in the overall device.

[0036] In one example, a substrate may include a multi-layer stack having one or more layers of dielectric material, such as low-k dielectric material or silicon oxide deposited by tetraethyl orthosilicate (TEOS). A capping or etch mask may be formed over the multi-layer stack to etch the dielectric material. However, in some cases, where etching is performed using certain carbon-containing and / or fluorine-containing species, chemical reactions may cause formation of byproducts by polymerization, thereby forming CxHyFz compounds (such as di fluoromethane(CH2F2)) on regions on the substrate, such as at the bottom of the features that are formed after etching. These materials may also contact metal underlayers that are below one or more of the dielectric material in the multi-layer stack. Certain etching techniques, such as wet etching, may be unable to fully clean these regions due to the high aspect ratio of the features or the deep feature depth in advanced patterning processes. In some cases, etching of these materials using hydrogen plasma or nitrogen plasma might also cause damage to the low-k dielectric sidewalls which may further cause profile bowing, collapse, or damage to the substrate.

[0037] Provided herein are methods and apparatuses for etching dielectric material without damaging other exposed materials on the substrate. Methods also include selectively etching dielectric material relative to other material. Methods also include treating a substrate using metastable activated radical species to remove polymerization and buildup of unwanted byproducts on the substrate surface while protecting exposed dielectric surfaces and preventing etching of the exposed dielectric surfaces. Certain disclosed embodiments may be employed in a chamber, station, tool, or apparatus having a remote plasma generator and manifold equipped to generate secondary excitation in the form of metastable activated radical species for etching the substrate. An example is described herein in the Apparatus section.

[0038] Figure 1 shows a process flow diagram depicting operations that may be performed in accordance with certain disclosed embodiments. Embodiments described herein may be performed on a substrate in a process chamber having a chamber pressure of about 100 mTorr to about 4000 mTorr, or about 700 mTorr to about 4000 mTorr, or about 1.1 Torr to about 2 Torr. Pressure may affect how much material may be removed when the substrate is later exposed to wet etching; a higher pressure may result in more wet etch loss. In certain embodiments increased pressure may result in more damage to low-k dielectric material.

[0039] Etching may be performed at a temperature of about 200°C to about 400°C. It will be understood that the temperature may depend on the materials on the substrate and in some embodiments, as temperature increases, etch rate of the material also increases.

[0040] In an operation 101, a substrate is provided to a process chamber. The substrate may be a silicon or other semiconductor wafer, e.g., a 200-mm wafer, a 300-mm wafer, or a 450-mm wafer, including wafers having one or more layers of material, such as dielectric, conducting, or semi-conducting material deposited thereon. In various embodiments, there may be a target layer to be etched. In some embodiments, the target layer is a metal-containing material. In some embodiments, the target layer is a photoresist material. In some embodiments, the target layer is a carbon-containing material. In some embodiments, a low-k dielectric layer may beover the target layer. In various embodiments, there may be a patterned mask over the low-k dielectric layer. The patterned mask may be a metal-containing material, or a silicon-containing material, or carbon-containing material. The mask may include titanium nitride. In some embodiments, the patterned mask is a dielectric layer having a different density or other property' compared to the low-k dielectric. For example, in some embodiments, the mask may include multiple layers.

[0041] The substrate may be provided to a process chamber. The process chamber may be a chamber of a multi-station or multi-chamber tool or apparatus for processing multiple wafers, or may be a chamber for processing a single wafer.

[0042] In some embodiments, the substrate has been previously etched to form holes or vias in the target layer and some byproduct deposition has occurred on the substrate. The byproducts may include carbon, hydrogen and / or fluorine-containing materials, or may be CxHyFzmaterial.

[0043] In an operation 104, a remote plasma species is generated in a remote plasma generator. The plasma may be an inductively coupled plasma. The remote plasma species may be generated by introducing an inert gas to the remote plasma generator and igniting it. Example inert gases include but are not limited to argon, hydrogen, neon, helium, krypton, xenon, and mixtures thereof. In some examples, a gas that is also used as a purge gas is used for generating the remote plasma species.

[0044] The inert gas may be introduced to the remote plasma generator at a specific flow rate. Example flow rates include but are not limited to about 500 seem to about 3000 seem or about 1000 seem to about 2000 seem. The inert gas may include one or more inert gases such as a mixture of inert gases. In some embodiments, the inert gas includes only argon. In some embodiments, the inert gas includes only hydrogen. In some embodiments, the inert gas includes hydrogen and argon. In some embodiments, a mixture of gases is used and the ratio of the two inert gases may depend on the etching desired on the substrate. In some embodiments, a mixture of argon and hydrogen may have a particular flow rate ratio of argon to hydrogen. In some embodiments, more hydrogen gas may be used in the mixture to increase etch rate.

[0045] Plasma may be generated using a plasma power of about 500W to about 6000W in some embodiments.

[0046] The remote plasma generator may create plasma including radicals, metastable species, and ions in the remote plasma generator. The remote plasma generator may be a dome in an upper chamber of the process chamber where the substrate is housed. The process chamber may include a gas distribution device that removes ions from the plasma, blocks ultraviolet lightgenerated by the plasma, and delivers metastable species to a lower chamber. The process chamber may have a manifold that separates the upper chamber from a lower chamber. The substrate may be housed in the lower chamber. In various embodiments, the dome may be surrounded by coils used to generate the plasma.

[0047] In an operation 106, the remote plasma species is introduced to the lower chamber to a processing region that the substrate is exposed to in the process chamber. In various embodiments, the remote plasma species is delivered to the lower chamber via the manifold. The manifold may have a first set of inlet holes from which remote plasma species generated in the remote plasma generator may pass through the manifold to be introduced to the lower chamber.

[0048] In an operation 108, a gas such as an etching gas is introduced to the manifold to deliver the gas to the process chamber. Example etching gases include but are not limited to a hydrocarbon gas, such as methane (CH4). In some embodiments, the gas is injected into the manifold from the side of the process chamber. The manifold includes a second set of inlet holes from which the etching gas may be delivered through such that the gases flowed through the second set of inlet holes does not interact with species flowed through the first set of inlet holes. For example, in various embodiments, the remote plasma species is introduced via the manifold to the processing region but does not react with the gas in the manifold. Rather, any reaction takes place in the processing region after the remote plasma species and gas are introduced into the processing region. The etching gas may be delivered at any suitable flow rate. In certain embodiments, the etching gas is delivered at a flow rate of about 500 seem to about 3000 seem, or about 500 seem to about 2000 seem, or about 800 seem to about 1500 seem.

[0049] In various embodiments, the manifold is not heated. In various embodiments, the manifold is positioned at the bottom of the dome between the remote plasma generator and the processing region over the substrate.

[0050] In some embodiments, hydrogen is used in the remote plasma generator to generate radicals. In some embodiments, hydrogen is flowed to the manifold directly (e.g.. bypassing the remote plasma generator) and delivered to the processing region. In some embodiments, one or more gases are flowed in separate inlets via the manifold. In some embodiments, gases that may not react may be flowed together via the manifold. In some embodiments, the manifold includes multiple inlets, a subset of which are used to deliver gases from the remote plasma generator and another subset of which are used to deliver etching gases that bypass the remote plasma generator.

[0051] In some embodiments, the amount of etching gas is at least about 10%, or about 25%, or about 40%, or about 44%, or about 50%, or between about 25% and about 50% of the overall flow of gases into the chamber, which includes gases flowed to the remote plasma generator.

[0052] In an operation 110, the substrate is exposed to metastable activated radical species for etching the material on the substrate. Metastable activated radical species may be generated by reacting the radicals from the remote plasma species with the etching gas. In some embodiments, where argon is used to generate the radicals and the etching gas is methane, the reaction may be a penning ionization reaction as follows:Ar* + CH4^ H + CH*3+ CxHy*

[0053] Etching may be performed selectively such that certain materials such as photoresist may be etched more quickly relative to low-k dielectric material. Etching may be performed for a duration of about 5 seconds to about 120 seconds, or about 30 seconds to about 90 seconds, or about 50 seconds.

[0054] In various embodiments, the inert gas and the etching gas are continuously flowed throughout etching. In some embodiments, the gas flows may be alternated. In some embodiments, it may be advantageous to continuously flow the inert gas and etching gas to maintain a population of metastable species in the processing region above the substrate.

[0055] Without being bound by a particular theory, it is believed that metastable species from the remote plasma species may transfer energy to the etching gas to generate radicals which the substrate is then exposed to. Without being bound by a particular theory, it is believed that the reaction between the radicals from the upper chamber and the etching gas delivered via the manifold forms H* radicals that remove polymers and therefore prevents buildup of polymers on the substrate during etching, and that the reaction also forms CHX* radicals which carbonizes exposed regions and protects low-k dielectric from being etched during the etching, thereby resulting in selective etching. In some embodiments, the H* radicals can react with carbon to become volatile, and CH3 molecules can form Si-C bonding with low-k dielectric material to passivate the surface and make the exposed regions of the low-k dielectric material less susceptible to etching by the H* radicals.

[0056] In some embodiments, the pedestal holding the substrate may be moved to achieve a desired gap between the pedestal and the manifold. For example, the gap may be about 1 inches to about 1.25 inches in distance.

[0057] In various embodiments, a pump may be used to continuously pump reaction byproducts from the chamber.

[0058] Figures 2A-2D show cross-sectional views of an example substrate undergoing various etching operations that results in byproducts on the device. Figure 2A shows a substrate 201 with underlayer 203, target layer 205, etch stop layer 207, low-k dielectric layer 209, TEOS layer 211, and patterned mask 213. Example materials for target layer 205 include but are not limited to carbon-containing material such as photoresist materials. In Figure 2A, the dielectric has been etched to form features to expose the etch stop layer at the bottom of the features.

[0059] Figure 2B shows the substrate 201 whereby the etch stop layer 207 has been opened by an etching operation, and a feature is being etched in target layer 205.

[0060] When etching in Figure 2B involves conventional etching techniques, buildup 213 of material ends up on the edges and comers of the feature, thereby causing device problems as shown in Figure 2C. The buildup 213 may include CxHyFz by-products.

[0061] When etching in Figure 2B involves certain disclosed embodiments, buildup 213 is not present and feature 223 has no buildup or byproduct deposition on the feature sidewalls or comers.

[0062] Figure 3A shows an example schematic illustration of an example the flow of gas and plasma species that may be used in accordance with certain disclosed embodiments. Chamber 300 includes a dome 302, where inert gas species such as argon 304 is introduced into. The dome 302 includes coils (not shown) that ignite the inert gas species to generate radicals 306 which can then be delivered to a substrate 308 on a pedestal 310. The radicals 306 travel via a first set of holes 313 as indicated by the first arrows 312 whereby the first set of holes 313 are in the manifold 314. An etching gas such as depicted by an example etching gas molecule 316 is flowed from the side of the chamber 300 to the manifold 314 and delivered to the substrate via a second set of holes 315 in the manifold 314 as indicated by the second arrows 318. When the etching gas molecules 316 react with the radicals 306, they may form a metastable activated radical species 320 w hich helps passivate regions of the substrate and etch the substrate without damaging dielectric materials on the substrate.

[0063] Figure 3B shows an example top view of a section of manifold 314. In this example, the first set of holes 313 for delivering radicals from the plasma generated in the dome are distributed along a plane of the manifold 314. A second set of holes 315 are used to deliver the etching gas molecules along the arrows 318.APPARATUS

[0064] Disclosed embodiments may be performed in any suitable etching chamber or apparatus, such as the Argos, available from Lam Research Corporation of Fremont, CA.Further description of plasma etch chambers may be found in U.S. Patent Nos. 6.841.943 and 8,552,334, which are herein incorporated by reference in their entireties.

[0065] Certain disclosed embodiments may be performed in particular tools or apparatuses. Figure 4 shows an example substrate processing system 400 which includes a processing chamber 410 including an upper region or upper chamber 412 and a lower region or lower chamber 416. In some example, the processing chamber 410 has a dome shape, although other shapes can be used. A showerhead 414 is arranged between the upper region 412 and the lower region 416 of the processing chamber 410. A substrate support or movable pedestal 420 is arranged in the lower region 416. In some examples, the substrate support 420 includes a baseplate 422 including cooling passages 423 and a top plate 424 attached by a bonding layer 426 to the baseplate 422. A substrate 430 is supported on the substrate support 420 during processing.

[0066] A first gas delivery system 140 supplies a first gas mixture to the upper region 412. In some examples, the first gas mixture includes plasma gas, purge gas, or another gas mixture. A second gas delivery system 446 supplies a second gas mixture to a port on the showerhead 414 described further below. In some examples, the second gas mixture includes a reactant species, a purge gas, or other gas mixture. In some examples, the first and second gas delivery systems 440 and 446 include one or more gas sources, one or more valves, and / or one or more mass flow controllers.

[0067] A plasma generating system 434 selectively supplies radio frequency (RF) power to inductive coils 435 arranged around the upper region 412 of the processing chamber 410. In some examples, the plasma generating system 434 includes an RF source 436 to supply an RF voltage and a matching network 438 to match an impedance of the inductive coils 435 to the RF source 436. A throttle valve 454 and a pump 456 evacuate reactants from the processing chamber 410 and / or control pressure within the processing chamber 410.

[0068] A temperature control system 460 is configured to control a temperature of the substrate 430 during processing. In some examples, a heater controller 464 supplies power to resistive heaters 428 arranged in the top plate 424. A cooling system 468 supplies a cooling fluid to the cooling passages 423 in the baseplate 422.

[0069] A controller 470 is configured to control the process. The controller 470 is configured to control the first and second gas mixtures supplied by the first and second gas delivery systems 440 and / or 446, and RF power supplied by the plasma generating system 434. The controller 470 is further configured to control a temperature of the substrate 430 during processing using thetemperature control system 460. The controller 470 is also configured to control pressure within the processing chamber 410 and / or to evacuate reactants from the processing chamber 410 using the throttle valve 454 and the pump 456.

[0070] In various embodiments, a system controller 470 is employed to control process conditions during deposition. The controller 470 will typically include one or more memory devices and one or more processors. A processor may include a CPU or computer, analog and / or digital input / output connections, stepper motor controller boards, etc.

[0071] The controller 470 may control all of the activities of the deposition apparatus. The system controller 470 executes system control software, including sets of instructions for controlling the timing, mixture of gases, chamber pressure, chamber temperature, wafer temperature, radio frequency (RF) power levels, wafer chuck or pedestal position, and other parameters of a particular process. Other computer programs stored on memory devices associated with the controller 470 may be employed in some embodiments.

[0072] Typically, a user interface will be associated with the controller 470. The user interface may include a display screen, graphical software displays of the apparatus and / or process conditions, and user input devices such as pointing devices, keyboards, touch screens, microphones, etc.

[0073] System control logic may be configured in any suitable way. In general, the logic can be designed or configured in hardware and / or software. The instructions for controlling the drive circuitry may be hard coded or provided as software. The instructions may be provided by “programming.” Such programming is understood to include logic of any form, including hard coded logic in digital signal processors, application-specific integrated circuits, and other devices which have specific algorithms implemented as hardware. Programming is also understood to include software or firmware instructions that may be executed on a general purpose processor. System control software may be coded in any suitable computer readable programming language.

[0074] The computer program code for controlling the germanium-containing reducing agent pulses, hydrogen flow, and tungsten-containing precursor pulses, and other processes in a process sequence can be written in any conventional computer readable programming language: for example, assembly language, C, C++, Pascal, Fortran, or others. Compiled object code or script is executed by the processor to perform the tasks identified in the program. Also as indicated, the program code may be hard coded.

[0075] The controller parameters relate to process conditions, such as, for example, processgas composition and flow rates, temperature, pressure, cooling gas pressure, substrate temperature, and chamber wall temperature. These parameters are provided to the user in the form of a recipe and may be entered utilizing the user interface. Signals for monitoring the process may be provided by analog and / or digital input connections of the system controller 470. The signals for controlling the process are output on the analog and digital output connections of the deposition apparatus 1100.

[0076] The system software may be designed or configured in many different ways. For example, various chamber component subroutines or control objects may be written to control operation of the chamber components necessary’ to carry out the deposition processes (and other processes, in some cases) in accordance with the disclosed embodiments. Examples of programs or sections of programs for this purpose include substrate positioning code, process gas control code, pressure control code, and heater control code.

[0077] In some implementations, a controller 470 is part of a system, which may be part of the above-described examples. Such systems can include semiconductor processing equipment, including a processing tool or tools, chamber or chambers, a platform or platforms for processing, and / or specific processing components (a wafer pedestal, a gas flow system, etc.). These systems may be integrated with electronics for controlling their operation before, during, and after processing of a semiconductor wafer or substrate. The electronics may be referred to as the “controller,” which may control various components or subparts of the system or systems. The controller 470, depending on the processing requirements and / or the type of system, may' be programmed to control any of the processes disclosed herein, including the delivery7of processing gases, temperature settings (e.g., heating and / or cooling), pressure settings, vacuum settings, power settings, radio frequency (RF) generator settings in some systems, RF matching circuit settings, frequency settings, flow rate settings, fluid delivery settings, positional and operation settings, wafer transfers into and out of a tool and other transfer tools and / or load locks connected to or interfaced with a specific system.

[0078] Broadly speaking, the controller may be defined as electronics having various integrated circuits, logic, memory', and / or software that receive instructions, issue instructions, control operation, enable cleaning operations, enable endpoint measurements, and the like. The integrated circuits may include chips in the form of firmware that store program instructions, digital signal processors (DSPs), chips defined as application specific integrated circuits (ASICs), and / or one or more microprocessors, or microcontrollers that execute program instructions (e.g., software). Program instructions may be instructions communicated to thecontroller in the form of various individual settings (or program files), defining operational parameters for carrying out a particular process on or for a semiconductor wafer or to a system. The operational parameters may, in some embodiments, be part of a recipe defined by process engineers to accomplish one or more processing steps during the fabrication of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or dies of a wafer.

[0079] The controller, in some implementations, may be a part of or coupled to a computer that is integrated with, coupled to the system, otherwise networked to the system, or a combination thereof. For example, the controller may be in the ’ cloud" or all or a part of a fab host computer system, which can allow for remote access of the wafer processing. The computer may enable remote access to the system to monitor current progress of fabrication operations, examine a history' of past fabrication operations, examine trends or performance metrics from a plurality of fabrication operations, to change parameters of current processing, to set processing steps to follow a current processing, or to start a new process. In some examples, a remote computer (e g. a server) can provide process recipes to a system over a network, which may include a local network or the Internet. The remote computer may include a user interface that enables entry' or programming of parameters and / or settings, which are then communicated to the system from the remote computer.

[0080] In some examples, the controller receives instructions in the form of data, which specify parameters for each of the processing steps to be performed during one or more operations. It should be understood that the parameters may be specific to the ty pe of process to be performed and the type of tool that the controller is configured to interface with or control. Thus as described above, the controller may be distributed, such as by comprising one or more discrete controllers that are networked together and working towards a common purpose, such as the processes and controls described herein. An example of a distributed controller for such purposes would be one or more integrated circuits on a chamber in communication with one or more integrated circuits located remotely (such as at the platform level or as part of a remote computer) that combine to control a process on the chamber.

[0081] Without limitation, example systems may include a plasma etch chamber or module, a deposition chamber or module, a spin-rinse chamber or module, a metal plating chamber or module, a clean chamber or module, a bevel edge etch chamber or module, a physical vapor deposition (PVD) chamber or module, a chemical vapor deposition (CVD) chamber or module, an atomic layer deposition (ALD) chamber or module, an atomic layer etch (ALE) chamber ormodule, an ion implantation chamber or module, a track chamber or module, and any other semiconductor processing systems that may be associated or used in the fabrication and / or manufacturing of semiconductor wafers.

[0082] As noted above, depending on the process step or steps to be performed by the tool, the controller might communicate with one or more of other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, neighboring tools, tools located throughout a factory, a main computer, another controller, or tools used in material transport that bring containers of wafers to and from tool locations and / or load ports in a semiconductor manufacturing factory.

[0083] The apparatus and processes described herein may be used in conjunction with lithographic patterning tools or processes, for example, for the fabrication or manufacture of semiconductor devices, displays, LEDs, photovoltaic panels, and the like. Typically, though not necessarily, such apparatus and processes will be used or conducted together in a common fabrication facility. Lithographic patterning of a film typically comprises some or all of the following steps, each step enabled with a number of possible tools: (1) application of photoresist on a work piece, i.e., a substrate, using a spin-on or spray-on tool; (2) curing of photoresist using a hot plate or furnace or UV curing tool; (3) exposing the photoresist to visible or UV or x- ray light with a tool such as a wafer stepper; (4) developing the resist so as to selectively remove resist and thereby pattern it using a tool such as a wet bench; (5) transferring the resist pattern into an underlying film or work piece by using a dry or plasma-assisted etching tool; and (6) removing the resist using a tool such as an RF or microwave plasma resist stripper.

[0084]

[0085] During substrate treatment such as selective etching of a film or stripping of photoresist, the first gas mixture including plasma gas is supplied by a gas injector 472 into the upper region 412 of the processing chamber 410. As used herein, selective etching means etching more of one exposed film material relative to one or more other exposed film materials (e.g., at a ratio greater than N: 1, where N is greater than 2). The plasma generating system 434 provides RF power to the inductive coils 435, which generate a magnetic field in the processing chamber 410 that is used to strike and / or maintain the plasma.

[0086] The plasma in the upper region 412 of the processing chamber 410 produces metastable species and ions. Since the showerhead 414 is grounded and the gas through holes in the showerhead 444 have a relatively high aspect ratio, most of the ions do not pass through the showerhead 414. However, the metastable species are neutral so they pass through the gasthrough holes.

[0087] The showerhead 414 also includes gas channels and gas through holes that supply the second gas mixture including the active etching species to the lower region 416 of the processing chamber 410 separately from the delivery of the metastable species. Upon reaching the lower region 416 of the processing chamber 410, the metastable species transfer energy to the second gas mixture (e g., the active etching species) to generate radicals for selective film removal.

[0088] Referring now to Figure 5, the showerhead 414 includes a flange 510 that is annular, defines an inner cavity' 512, and has an inner diameter. A side wall 514 extends downwardly from a radially inner edge of the flange 510. A surface 516 extends between bottom edges of the side wall 514. The surface 516, a braze layer 526, and a cover plate 528 include aligned gas through holes 520 to allow metastable species to pass from the upper region 412 above the showerhead 414 to the lower region 416 below the showerhead 414 without contacting the second gas mixture. While an example of a pattern of the gas through holes 520 is shown with no through holes (e.g., in regions 531 where gas channels are not located), other patterns may include gas through holes in the regions 531 .EXPERIMENTALEXPERIMENT 1

[0089] An experiment was conducted to evaluate etching of a photoresist material using a lowly dielectric mask under various conditions. The first set of conditions involved etching using radicals generated from igniting argon and hydrogen in a remote plasma chamber without using a manifold to deliver an etching gas. The second set of conditions involved etching using radicals generated from igniting argon and hydrogen in a remote plasma chamber while using a manifold to deliver methane as an etching gas. The third set of conditions involved etching using radicals generated from igniting argon in a remote plasma chamber while using a manifold to deliver methane as an etching gas.

[0090] The results evaluated were (1) the amount of low-k material lost during the etching after a wet cleaning operation using dilute hydrofluoric acid, and (2) the amount of carbon depletion, and (3) etch rate of the photoresist. The results are summarized in Table 1.Table 1. Carbon Etching

[0091] The results suggest that carbon depletion was substantially reduced and low-k dielectric loss was also substantially reduced.EXPERIMENT 2

[0092] An experiment was conducted on three substrates. The substrates included a silicon layer, a silicon oxide layer over the silicon layer, and a hafnium oxide layer over the silicon oxide layer. The first substrate was not exposed to any etchant. The second substrate was exposed to etching using CH2F2 / C4F8 / CO / CF4. The third substrate was exposed to etching using CH2F2 / C4F8 / CO / CF4 and then additional etching was performed by delivering (1) radicals generated from argon delivered to a remote plasma species generating plasma at 2700W at a flow rate of 4500 seem and (2) 2000 seem methane gas via a metastable activated radical species manifold for 60 seconds at 200°C and 1.1 Torr.

[0093] The second substrate showed carbon-based by-products in the imaging results. The third substrate showed little to no carbon-based by-products in the imaging results, suggesting the additional etching performed reduced the formation of by-products.CONCLUSION

[0094] Although the foregoing embodiments have been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be practiced within the scope of the appended claims. It should be noted that there are many alternative ways of implementing the processes, systems, and apparatus of the present embodiments. Accordingly, the present embodiments are to be considered as illustrative and not restrictive, and the embodiments are not to be limited to the details given herein.

Claims

CLAIMSWhat is claimed is:

1. A method for processing substrates, the method comprising: providing a substrate having a target material deposited thereon to a process chamber having a processing region; generating radicals of an inert gas in a remote plasma generator; introducing the radicals to the processing region; introducing an etching gas downstream of the remote plasma generator, wherein the etching gas reacts with the radicals in the processing region to form an etching species; and exposing the target material to the etching species in the processing region.

2. The method of claim 1, wherein the etching gas is delivered through a manifold positioned between the processing region and the remote plasma generator.

3. The method of claim 1, wherein the etching species comprises metastable activated radical species.

4. The method of claim 1, wherein the remote plasma generator is an inductively coupled plasma generator.

5. The method of claim 1, wherein the remote plasma generator is dome-shaped.

6. The method of claim 1, wherein penning ionization occurs in the processing region to react the radicals with the etching gas.

7. The method of claim 1. wherein the etching gas comprises methane.

8. The method of claim 1, wherein the etching species is selected from the group consisting of hydrogen radicals, CH3* radicals, and CxHy* radicals.

9. The method of claim 1, wherein the etching species comprises radicals.

10. The method of claim 1, wherein the inert gas is selected from a group consisting of hydrogen gas, argon gas, and combinations thereof.

11. The method of any of claims 1-10, w herein the substrate further comprises a low-kdielectric material.

12. The method of any of claims 1-10, wherein the substrate further comprises one or more layers having materials selected from the group consisting of silicon oxide, silicon nitride, poly- sihcon. and amorphous silicon.

13. The method of any of claims 1-10, wherein etching is performed until a metal or metal nitride material is exposed.

14. The method of any of claims 1-10, wherein the target material is a photoresist material.

15. The method of any of claims 1-10, wherein the target material is a carbon, hydrogen, and fluorine-containing material.

16. The method of any of claims 1-10, wherein the target material is etched selective to a second material.

17. The method of claim 16, wherein the second material is silicon oxide or low-k dielectric material.

18. The method of any of claims 1-10. wherein the process chamber is set to a chamber pressure of about 700 mTorr to about 4000 mTorr.

19. The method of any of claims 1-10, wherein the substrate is provided on a pedestal, and wherein a gap between the pedestal and manifold is about 1 inch to about 1.25 inches.

20. A method for processing substrates, the method comprising: providing a substrate having a target material deposited thereon to a process chamber having a remote plasma generator and a lower chamber, wherein a manifold separates the remote plasma generator and the lower chamber; flowing an inert gas to a remote plasma generator, wherein the inert gas is selected from the group consisting of hydrogen, argon, and mixtures thereof generating radicals in the remote plasma generator; delivering radicals from the remote plasma generator to the lower chamber; flowing methane gas directly to the manifold, wherein the manifold distributes methane gas to the lower chamber; reacting methane gas with the radicals to generate a metastable activated radical species;and etching the target material with the metastable activated radical species.

21. An apparatus for processing substrates, the apparatus comprising: a process chamber comprising a manifold dividing the process chamber into an upper chamber and a lower chamber; a movable pedestal in the lower chamber; a remote inductively-coupled plasma generator in the upper chamber; one or more gas inlets for delivering a first gas into the upper chamber and a first associated flow-control hardware; a gas source for delivering a second gas to the manifold without delivering the second gas to the upper chamber; one or more gas inlets for delivering a second gas into the manifold and a second associated flow-control hardware; and a controller having at least one processor and a memory, wherein the at least one processor and the memory are communicatively connected with one another, the at least one processor is at least operatively connected with the first and second flowcontrol hardware, and the memory stores computer-executable instructions for controlling the at least one processor to at least control the flow-control hardware to: cause generation of radicals in the upper chamber; cause introduction of the radicals from the upper chamber to the lower chamber; cause introduction of the second gas via the manifold to the lower chamber; cause generation of metastable species in the lower chamber; and cause etching of a material on a substrate on the pedestal using the metastable species.

22. The apparatus of claim 21, wherein the manifold and movable pedestal are separated by a gap having a distance of about 1 inch to about 1.25 inches.

23. The apparatus of claim 21, wherein the manifold comprises two or more sets of holes, at least one set for delivering species from the upper chamber to the lower chamber, and at least one set for deliver species from the gas source to the lower chamber without delivering the species into the upper chamber.

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