Selective removal of metal-and-carbon-containing materials

Abstract

Exemplary etching methods may include providing an oxygen-containing precursor to a processing region of a semiconductor processing chamber. A substrate may be housed within the processing region. A metal-and-carbon-containing material may be disposed on the substrate. The methods may include contacting the substrate with the oxygen-containing precursor. The contacting the substrate may oxidize at least a portion of the metal-and-carbon-containing material to form a metal-and-oxygen-containing material. The methods may include providing a halogen-containing precursor to the processing region of the semiconductor processing chamber. The methods may include contacting the metal-and-oxygen-containing material with the halogen-containing precursor. The contacting the metal-and-oxygen-containing material may etch the metal-and-oxygen-containing material.

Description

PATENT KTS No.: 080042-44025044W001-1468607SELECTIVE REMOVAL OF METAL- AND-CARBON-CONTAINING MATERIALSTECHNICAL FIELD

[0001] The present technology relates to semiconductor processes and equipment. More specifically, the present technology relates to selectively etching metal-and-carbon-containing structures.BACKGROUND

[0002] Integrated circuits are made possible by processes which produce intricately patterned material layers on substrate surfaces. Producing patterned material on a substrate requires controlled methods for removal of exposed material. Chemical etching is used for a variety of purposes including transferring a pattern in photoresist into underlying layers, thinning layers, or thinning lateral dimensions of features already present on the surface. Often it is desirable to have an etch process that etches one material faster than another facilitating, for example, a pattern transfer process. Such an etch process is said to be selective to the first material. As a result of the diversity of materials, circuits, and processes, etch processes have been developed with a selectivity' towards a variety' of materials.

[0003] Etch processes may be termed wet or dry' based on the materials used in the process. For example, a wet etch may preferentially remove some oxide dielectrics over other dielectrics and materials. However, wet processes may have difficulty penetrating some constrained trenches and also may' sometimes deform the remaining material. Dry etches produced in local plasmas formed within the processing region can penetrate more constrained trenches and exhibit less deformation of delicate remaining structures. However, local plasmas may damage the substrate through the production of electric arcs as they discharge.

[0004] Thus, there is a need for improved systems and methods that can be used to produce high quality' devices and structures. These and other needs are addressed by the present technology.SUMMARY

[0005] Exemplary etching methods may include providing an oxygen-containing precursor to a processing region of a semiconductor processing chamber. A substrate may be housed within the processing region. A metal-and-carbon-containing material may be disposed on the substrate. The methods may include contacting the substrate with the oxygen-containing precursor. The contacting the substrate may oxidize at least a portion of the metal-and-carbon-containing material to form a metal-and-oxygen-containing material. The methods may include providing a halogen-containing precursor to the processing region of the semiconductor processing chamber. The methods may include contacting the metal-and-oxygen-containing material with the halogen-containing precursor. The contacting the metal-and-oxygen-containing material may etch the metal-and-oxygen-containing material.

[0006] In embodiments, the oxygen-containing precursor may be or include atomic oxygen (O), diatomic oxygen (O2), ozone (O3), nitrous oxide (N2O), nitrogen dioxide (NO2), water or steam (H2O), or hydrogen peroxide (H2O2). A metal of the metal-and-carbon-containing material may be or include titanium (Ti) or niobium (Nb). The methods may include providing a hydrogen-containing precursor to the processing region with the oxy gencontaining precursor. The hydrogen-containing precursor comprises may be or include diatomic hydrogen (H2), ammonia (NHs), water or steam (H2O), hydrogen peroxide (H2O2), diimide (N2H2), or hydrazine (N2H4). A flow rate ratio of the hydrogen-containing precursor relative to the oxy gen-containing precursor may be between about 500: 1 and about 1:500. The methods may include forming plasma effluents of the oxy gen-containing precursor. The methods may include halting a flow of the oxygen-containing precursor prior to providing the halogen-containing precursor. The halogen-containing precursor may be or include boron trichloride (BCh), tungsten hexafluoride (WFe). or carbon tetrafluoride (CF4). The methods may include forming plasma effluents of the halogen-containing precursor. A temperature within the processing region may be maintained at greater than or about 200 °C.

[0007] Some embodiments of the present technology may encompass semiconductor processing methods. The methods may include i) providing an oxy gen-containing precursor and a hydrogen-containing precursor to a processing region of a semiconductor processing chamber. A substrate may be housed within the processing region. A metal-and-carbon-containing material may be disposed on the substrate. The methods may include ii) contacting the substrate with the oxygen-containing precursor and hydrogen-containing precursor. The contacting t he substrate may oxidize at least a portion of the metal-and-carbon-containing material to form a metal-and-oxygen-containing material. The methods may include iii) halting a flow of the oxy gen-containing precursor and / or a flow of the hydrogen-containing precursor. The methods may include iv) providing a halogencontaining precursor to the processing region of the semiconductor processing chamber. The methods may include v) contacting the metal-and-oxygen-containing material with the halogen-containing precursor. The contacting the metal-and-oxygen-containing material may etch the metal-and-oxygen-containing material. A temperature within the processing region may be maintained at greater than or about 350 °C.

[0008] In embodiments, the metal-and-carbon-containing material may be or include a titanium-aluminum-and-carbon-containing material (TiAlC) or a niobium-aluminum-and-carbon-containing material (NbAlC). A flow rate ratio of the hydrogen-containing precursor relative to the oxy gen-containing precursor may be between about 500: 1 and about 1:500. A thickness of the metal-and-oxygen-containing material may be less than or about 3 nm. A pressure within the processing region may be maintained at greater than or about 1 Torr. The methods may include repeating operations i-v for a plurality of cycles.

[0009] Some embodiments of the present technology may encompass semiconductor processing methods. The methods may include providing an oxygen-containing precursor and a hydrogen-containing precursor to a processing region of a semiconductor processing chamber. A substrate may be housed within the processing region. A metal-and-carbon-containing material may be disposed on the substrate. The methods may include forming plasma effluents of the oxygen-containing precursor and the hydrogen-containing precursor. The methods may include contacting the substrate with the plasma effluents of the oxygencontaining precursor and the hydrogen-containing precursor. The contacting the substrate may oxidize at least a portion of the metal-and-carbon-containing material to form a metal-and-oxygen-containing material. The methods may include providing a halogen-containing precursor to the processing region of the semiconductor processing chamber. The methods may include contacting the metal-and-oxygen-containing material with the plasma effluents of the halogen-containing precursor. The contacting the metal-and-oxygen-containing material may etch the metal-and-oxygen-containing material.

[0010] In embodiments, contacting the substrate with the plasma effluents of the oxygencontaining precursor and the hydrogen-containing precursor may volatilize a carbon-hydrogen-and-oxygen-containing material. A temperature within the processing region may be maintained at greater than or about 200 °C.

[0011] Such technology may provide numerous benefits over conventional systems and techniques. For example, the processes may allow a precisely controlled dry etch to be performed, which may remove discreet layers of metal-and-carbon-containing materials. Additionally, the processes may selectively remove metal-and-carbon-containing films relative to other exposed materials on the substrate. These and other embodiments, along with many of their advantages and features, are described in more detail in conjunction with the below description and attached figures.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] A further understanding of the nature and advantages of the disclosed technology may be realized by reference to the remaining portions of the specification and the drawings.

[0013] FIG. 1 shows a top plan view of one embodiment of an exemplary processing system according to some embodiments of the present technology.

[0014] FIG. 2A shows a schematic cross-sectional view of an exemplary processing chamber according to some embodiments of the present technology.

[0015] FIG. 2B shows a detailed view of a portion of the processing chamber illustrated in FIG. 2A according to some embodiments of the present technology.

[0016] FIG. 3 shows a bottom plan view of an exemplary showerhead according to some embodiments of the present technology.

[0017] FIG. 4 shows exemplary operations in a method according to some embodiments of the present technology7.

[0018] FIGS. 5A-5D show schematic cross-sectional views of materials etched according to some embodiments of the present technology.

[0019] Several of the figures are included as schematics. It is to be understood that the figures are for illustrative purposes, and are not to be considered of scale unless specifically stated to be of scale. Additionally, as schematics, the figures are provided to aid comprehension and may not include all aspects or information compared to realistic representations, and may include additional or exaggerated material for illustrative purposes.

[0020] In the appended figures, similar components and / or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a letter that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the letter.DETAILED DESCRIPTION

[0021] Conventional metal carbide material etching methods may utilize reactive ion etching (RIE) methods that utilize halogen-containing precursors, such as boron-and-halogen-containing precursors. However, while the RIE methods may etch the metal carbide material, the RIE methods may also damage other materials present in the structures being processed. As such, the RIE methods may not etch metal carbide material as selectively as desired or needed. Additionally, the RIE methods may not uniformly etch the metal carbide material and may produce an etched metal carbide material with a rough surface. Finally, the halogen-containing precursors, such as boron-and-halogen-containing precursors, may¬ deposit a residue, such as a boron-containing residue on the structures being processed or elsewhere within the processing region.

[0022] The present technology overcomes these limitations by performing metal carbide material etching methods where the metal carbide material may be sequentially oxidized and etched. Oxidizing the metal carbide material may form an oxidized metal material that maybe etched using a halogen-containing precursor. Additionally, the present technology may utilize a plasma-based or plasma-free / thermal process, which may further protect the structures being processed. Furthermore, the present technology may remove metal carbide material in discreet layers, which may be performed selectively to surrounding materials. By removing metal carbide material by releasing oxidized materials, the present technology may provide an etch process that provides a smoother interface surface compared to many-conventional etches.

[0023] Although the remaining disclosure will routinely identify specific materials and semiconductor structures utilizing the disclosed technology-, it will be readily understood that the systems, methods, and materials are equally applicable to a number of other structures that may benefit from aspects of the present technology. Accordingly, the technology should not be considered to be so limited as for use with any specific processes or materials alone.Moreover, although an exemplary chamber is described to provide foundation for the present technology, it is to be understood that the present technology can be performed in virtually any semiconductor processing chamber that may allow the operations described.

[0024] FIG. 1 shows a top plan view of one embodiment of a processing system 100 of deposition, etching, baking, and curing chambers according to embodiments. In the figure, a pair of front opening unified pods 102 supply substrates of a variety' of sizes that are received by robotic arms 104 and placed into a low pressure holding area 106 before being placed into one of the substrate processing chambers 108a-f, positioned in tandem sections 109a-c. A second robotic arm 110 may' be used to transport the substrate wafers from the holding area 106 to the substrate processing chambers 108a-f and back. Each substrate processing chamber 108a-f, can be outfitted to perform a number of substrate processing operations including the dry etch processes described herein in addition to cyclical layer deposition, atomic layer deposition, chemical vapor deposition, physical vapor deposition, etch, preclean, degas, orientation, and other substrate processes.

[0025] The substrate processing chambers 108a-f may include one or more system components for depositing, annealing, curing and / or etching a dielectric film on the substrate wafer. In one configuration, two pairs of the processing chambers, e.g., 108c-d and 108e-f, may be used to deposit dielectric material on the substrate, and the third pair of processing chambers, e.g., 108a-b, may be used to etch the deposited dielectric. In another configuration, all three pairs of chambers, e.g., 108a-f, may be configured to etch a dielectric film on the substrate. Any one or more of the processes described may be carried out in one or more chamber separated from the fabrication system shown in different embodiments. It will be appreciated that additional configurations of deposition, etching, annealing, and curing chambers for dielectric films are contemplated by system 100.

[0026] FIG. 2A shows a cross-sectional view of an exemplary process chamber system 200 with partitioned plasma generation regions within the processing chamber. During film etching, e.g., metal carbide, titanium nitride, tantalum nitride, tungsten, silicon, polysilicon, silicon oxide, silicon nitride, silicon oxynitride, silicon oxy carbide, for example, a process gas may be flowed into the first plasma region 215 through a gas inlet assembly 205. A remote plasma system 201 may optionally be included in the system, and may process a first gas which then travels through gas inlet assembly 205. The inlet assembly 205 may includetwo or more distinct gas supply channels where the second channel may bypass the remote plasma system 201, if included.

[0027] A cooling plate 203, faceplate 217, ion suppressor 223, showerhead 225, and a pedestal 265 or substrate support, having a substrate 255 disposed thereon, are shown and may each be included according to embodiments. The pedestal 265 may have a heat exchange channel through which a heat exchange fluid flows to control the temperature of the substrate, which may be operated to heat and / or cool the substrate or wafer during processing operations. The wafer support platter of the pedestal 265, which may include aluminum, ceramic, or a combination thereof, may also be resistively heated in order to achieve relatively high temperatures, such as from up to or about 100 °C to above or about 1100 °C, using an embedded resistive heater element.

[0028] The faceplate 217 may be pyramidal, conical, or of another similar structure with a narrow top portion expanding to a wide bottom portion. The faceplate 217 may additionally be flat as shown and include a plurality of through-channels used to distribute process gases. Plasma generating gases and / or plasma excited species, depending on use of the remote plasma system 201, may pass through a plurality’ of holes, shown in FIG. 2B. in faceplate 217 for a more uniform delivery into the first plasma region 215.

[0029] Exemplary configurations may include having the gas inlet assembly 205 open into a gas supply region 258 partitioned from the first plasma region 215 by faceplate 217 so that the gases / species flow through the holes in the faceplate 217 into the first plasma region 215. Structural and operational features may be selected to prevent significant backflow of plasma from the first plasma region 215 back into the supply region 258. gas inlet assembly 205, and fluid supply system 210. The faceplate 217, or a conductive top portion of the chamber, and showerhead 225 are show n with an insulating ring 220 located between the features, which allows an AC potential to be applied to the faceplate 217 relative to showerhead 225 and / or ion suppressor 223. The insulating ring 220 may be positioned between the faceplate 217 and the showerhead 225 and / or ion suppressor 223 enabling a capacitively-coupled plasma to be formed in the first plasma region. A baffle may additionally be located in the first plasma region 215, or otherw ise coupled with gas inlet assembly 205, to affect the flow' of fluid into the region through gas inlet assembly 205.

[0030] The ion suppressor 223 may comprise a plate or other geometry that defines a plurality of apertures throughout the structure that are configured to suppress the migration ofionically-charged species out of the first plasma region 215 while allowing uncharged neutral or radical species to pass through the ion suppressor 223 into an activated gas delivery region between the suppressor and the showerhead. In embodiments, the ion suppressor 223 may comprise a perforated plate with a variety of aperture configurations. These uncharged species may include highly reactive species that are transported with less reactive carrier gas through the apertures. As noted above, the migration of ionic species through the holes may be reduced, and in some instances completely suppressed. Controlling the amount of ionic species passing through the ion suppressor 223 may advantageously provide increased control over the gas mixture brought into contact wi th the underlying wafer substrate, which in turn may increase control of the deposition and / or etch characteristics of the gas mixture. For example, adjustments in the ion concentration of the gas mixture can significantly alter its etch selectivity, e.g., SiNx:SiOx etch ratios, Si:SiOx etch ratios, etc. In alternative embodiments in which deposition is performed, it can also shift the balance of conformal-to-flowable sty le depositions for dielectric materials.

[0031] The plurality of apertures in the ion suppressor 223 may be configured to control the passage of the activated gas. i.e.. the ionic, radical, and / or neutral species, through the ion suppressor 223. For example, the aspect ratio of the holes, or the hole diameter to length, and / or the geometry of the holes may be controlled so that the flow of ionically-charged species in the activated gas passing through the ion suppressor 223 is reduced. The holes in the ion suppressor 223 may include a tapered portion that faces the plasma excitation region 215, and a cylindrical portion that faces the showerhead 225. The cylindrical portion may be shaped and dimensioned to control the flow of ionic species passing to the showerhead 225. An adjustable electrical bias may also be applied to the ion suppressor 223 as an additional means to control the flow of ionic species through the suppressor.

[0032] The ion suppressor 223 may function to reduce or eliminate the amount of ionically charged species traveling from the plasma generation region to the substrate. Uncharged neutral and radical species may still pass through the openings in the ion suppressor to react with the substrate. It should be noted that the complete elimination of ionically charged species in the reaction region surrounding the substrate may not be performed in embodiments. In certain instances, ionic species are intended to reach the substrate in order to perform the etch and / or deposition process. In these instances, the ion suppressor may help to control the concentration of ionic species in the reaction region at a level that assists the process.

[0033] Showerhead 225 in combination with ion suppressor 223 may allow a plasma present in first plasma region 215 to avoid directly exciting gases in processing region 233, while still allowing excited species to travel from chamber plasma region 215 into processing region 233. In this way, the chamber may be configured to prevent the plasma from contacting a substrate 255 being etched. This may advantageously protect a variety' of intricate structures and films patterned on the substrate, which may be damaged, dislocated, or otherwise warped if directly contacted by a generated plasma. Additionally, when plasma is allowed to contact the substrate or approach the substrate level, the rate at which oxide species etch may increase. Accordingly, if an exposed region of material is oxide, this material may be further protected by maintaining the plasma remotely from the substrate.

[0034] The processing system may further include a power supply 240 electrically coupled with the processing chamber to provide electric power to the faceplate 217. ion suppressor 223, showerhead 225, and / or pedestal 265 to generate a plasma in the first plasma region 215 or processing region 233. The power supply may be configured to deliver an adjustable amount of power to the chamber depending on the process performed. Such a configuration may allow for a tunable plasma to be used in the processes being performed. Unlike a remote plasma unit, which is often presented with on or off functionality, a tunable plasma may be configured to deliver a specific amount of power to the plasma region 215. This in turn may allow development of particular plasma characteristics such that precursors may be dissociated in specific ways to enhance the etching profiles produced by these precursors.

[0035] A plasma may be ignited either in chamber plasma region 215 above showerhead 225 or processing region 233 below showerhead 225. Plasma may be present in chamber plasma region 215 to produce the radical precursors from an inflow of, for example, a fluorine-containing precursor or other precursor. An AC voltage typically in the radio frequency (“RF”) range may be applied between the conductive top portion of the processing chamber, such as faceplate 217, and showerhead 225 and / or ion suppressor 223 to ignite a plasma in chamber plasma region 215 during deposition. An RF power supply may generate a high RF frequency of 13.56 MHz but may also generate other frequencies alone or in combination with the 13.56 MHz frequency.

[0036] FIG. 2B shows a detailed view 253 of the features affecting the processing gas distribution through faceplate 217. As shown in FIGS. 2A and 2B. faceplate 217, cooling plate 203, and gas inlet assembly 205 intersect to define a gas supply region 258 into whichprocess gases may be delivered from gas inlet 205. The gases may fdl the gas supply region 258 and flow to first plasma region 215 through apertures 259 in faceplate 217. The apertures 259 may be configured to direct flow in a substantially unidirectional manner such that process gases may flow into processing region 233, but may be partially or fully prevented from backflow into the gas supply region 258 after traversing the faceplate 217.

[0037] The gas distribution assemblies such as showerhead 225 for use in the processing chamber section 200 may be referred to as dual channel showerheads and are additionally detailed in the embodiments described in FIG. 3. The dual channel showerhead may provide for etching processes that allow for separation of etchants outside of the processing region 233 to provide limited interaction with chamber components and each other prior to being delivered into the processing region.

[0038] The showerhead 225 may comprise an upper plate 214 and a lower plate 216. The plates may be coupled with one another to define a volume 218 between the plates. The coupling of the plates may be so as to provide first fluid channels 219 through the upper and lower plates, and second fluid channels 221 through the lower plate 216. The formed channels may be configured to provide fluid access from the volume 218 through the lower plate 216 via second fluid channels 221 alone, and the first fluid channels 219 may be fluidly isolated from the volume 218 between the plates and the second fluid channels 221. The volume 218 may be fluidly accessible through a side of the showerhead 225.

[0039] FIG. 3 is a bottom view of a showerhead 325 for use with a processing chamber according to embodiments. Showerhead 325 may correspond with the showerhead 225 shown in FIG. 2A. Through-holes 365, which show a view of first fluid channels 219. may have a plurality of shapes and configurations in order to control and affect the flow of precursors through the showerhead 225. Small holes 375, which show a view of second fluid channels 221, may be distributed substantially evenly over the surface of the showerhead, even amongst the through-holes 365, and may help to provide more even mixing of the precursors as they exit the showerhead than other configurations.

[0040] The chamber discussed previously may be used in performing exemplary methods, including etching methods, although any number of chambers may be configured to perform one or more aspects used in embodiments of the present technology. Turning to FIG. 4, exemplary operations in a method 400, according to embodiments of the present technology, are illustrated. Method 400 may include one or more operations prior to the initiation of themethod, including front end processing, deposition, etching, polishing, cleaning, or any other operations that may be performed prior to the described operations. The method may include a number of optional operations, which may or may not be specifically associated with some embodiments of methods, according to embodiments of the present technology. For example, many of the operations are described in order to provide a broader scope of the processes performed, but are not critical to the technology’, or may be performed by alternative methodology as will be discussed further below. Method 400 may describe operations shown schematically in FIGS. 5A-5D, the illustrations of which will be described in conjunction with the operations of method 400. It is to be understood that the figures illustrate only partial schematic views, and a substrate may contain any number of additional materials and features having a variety of characteristics and aspects as illustrated in the figures.

[0041] Method 400 may or may not involve optional operations to develop the semiconductor structure to a particular fabrication operation. It is to be understood that method 400 may be performed on any number of semiconductor structures 500 or substrates 505, as illustrated in FIG. 5A, including exemplary structures on which a metal-and-carbon-containing material removal operation may be performed. Exemplary semiconductor structures may include a trench, via, or other recessed features that may include one or more exposed materials. For example, an exemplary’ substrate may contain silicon or some other semiconductor substrate material as well as interlayer dielectric materials through which a recess, trench, via. or isolation structure may be formed. Exposed materials at any time during the etch process may be or include metal materials, one or more dielectric materials, a contact material, a transistor material, or any other material that may be used in semiconductor processes.

[0042] For example, although shown as a generic layer. FIG. 5A may illustrate a layer of metal-and-carbon-containing material 510 overlying substrate 505 or some other semiconductor material. Although the remaining disclosure will reference metal-and-carbon-containing material, it is to be understood that the metal-and-carbon-containing material 510 may also include other substituents, such as nitrogen, carbon, hydrogen, or any other material. In embodiments, a metal of the metal-and-carbon-containing material 510 may be or include titanium (Ti) or niobium (Nb). For example, the metal-and-carbon-containing material 510 may be a titanium-aluminum-and-carbon-containing material (e.g., TiAlC) or a niobium-aluminum-and-carbon-containing material (e.g., NbAlC). However, other metal -and-carbon-containing materials, such as metal-aluminum-and-carbon-containing materials are contemplated by the present disclosure. Substrate 505 may illustrate a dielectric material overlying one or more other structures on a substrate, and it is to be understood that any number of materials may be formed beneath the structure illustrated. In some embodiments, dielectric materials may be or include silicon oxide, or any other oxide or nitride through which patterning may occur. It is to be understood that the noted structure is not intended to be limiting, and any of a variety of other semiconductor structures including metal-and-carbon-containing materials are similarly encompassed. Other exemplary structures may include two-dimensional and three-dimensional structures common in semiconductor manufacturing, and within which a metal-and-carbon-containing material such as TiAlC or NbAlC, is to be removed relative to one or more other materials, as the present technology may selectively remove metal-and-carbon-containing materials relative to other exposed materials, such as silicon oxide, silicon nitride, silicon germanium, titanium oxide, tungsten oxide, and any of the other materials discussed elsewhere, among a variety of other exposed materials. Additionally, although a high-aspect-ratio structure may benefit from the present technology, the technology may be equally applicable to lower aspect ratios and any other structures.

[0043] Method 400 may be performed to remove an exposed metal-and-carbon-containing material in embodiments of the present technology. The methods may include specific operations for the removal of metal carbides or metal-and-carbon-containing materials. In some embodiments, the methods may include a multiple-operation oxidation and etch process, which may control etching of the metal-and-carbon-containing material relative to other exposed materials, such as dielectric material, for example silicon oxide, silicon nitride, silicon germanium, as well as any underlying contact material, such as a conductive material used in the structure, which may be coupled with one or more device structures.

[0044] Method 400 may include providing an oxygen-containing precursor to a semiconductor processing chamber housing the described substrate 505 at operation 405. In some embodiments, the oxygen-containing precursor may be flowed directly to contact the substrate 505, although in other embodiments a plasma may be formed of the oxy gencontaining precursor at optional operation 410 prior to contacting the substrate 505. The plasma may be formed remotely, or within a processing region of the semiconductor processing chamber in which the substrate 505 is housed. The oxygen-containing precursor may be flowed through a remote plasma region of the processing chamber, such as region215 described above, and a plasma may be formed of the oxy gen-containing precursor to produce plasma effluents. Although a substrate-level plasma may be produced, in some embodiments the plasma may be a remote plasma, which may protect exposed substrate materials from ion bombardment that may occur due to the substrate-level plasma.

[0045] In embodiments, the oxygen-containing precursor may be or include, but is not limited to, atomic oxygen (O), diatomic oxygen (O2), ozone (O3), nitrous oxide (N2O), nitrogen dioxide (NO2), water or steam (H2O), hydrogen peroxide (H2O2), or any other oxygen-containing precursor used or useful in semiconductor processing. A flow rate of the oxygen-containing precursor may be greater than or about 100 seem, and may be greater than or about 200 seem, greater than or about 300 seem, greater than or about 400 seem, greater than or about 500 seem, greater than or about 600 seem, greater than or about 700 seem, greater than or about 800 seem, greater than or about 900 seem, greater than or about 1,000 seem, or more. Higher flow rates of the oxygen-containing precursor may increase oxidation of the metal-and-carbon-containing material. However, oxidation may begin to saturate at increased flow rates of the oxygen-containing precursor. As such, to balance the oxidation and effectiveness of the oxygen-containing precursor, the flow rate of the oxygen-containing precursor may be less than or about 1,000 seem, and may be less than or about 900 seem, less than or about 800 seem, less than or about 700 seem, less than or about 600 seem, less than or about 500 seem, less than or about 400 seem, less than or about 300 seem, less than or about 200 seem, less than or about 100 seem, or less. The oxygen-containing precursor may be provided with or include one or more diluents or carrier gases, such as an inert gas or other gas delivered with the oxy gen-containing precursor.

[0046] In embodiments, method 400 may additionally include providing a hydrogencontaining precursor to the semiconductor processing chamber with the oxygen-containing precursor housing the described substrate 505 at operation 405. The hydrogen-containing precursor may be provided to the semiconductor processing chamber with or separately from the oxygen-containing precursor. As such, in some embodiments, the hydrogen-containing precursor may be flowed directly to contact the substrate 505, although in other embodiments a plasma may be formed of the hydrogen-containing precursor at optional operation 410 prior to contacting the substrate 505. Similar to the oxygen-containing precursor, the plasma may be formed remotely, or within a processing region of the semiconductor processing chamber in which the substrate 505 is housed. The hydrogen-containing precursor may be flowed through a remote plasma region of the processing chamber, such as region 215 describedabove, and a plasma may be formed of the hydrogen-containing precursor to produce plasma effluents. Although a substrate-level plasma may be produced, in some embodiments the plasma may be a remote plasma, which may protect exposed substrate materials from ion bombardment that may occur due to the substrate-level plasma.

[0047] In embodiments, the hydrogen-containing precursor may be or include, but is not limited to, diatomic hydrogen (H2), ammonia (NH3), water or steam (H2O), hydrogen peroxide (H2O2). diimide (N2H2), hydrazine (N2H4), or any other hydrogen-containing precursor used or useful in semiconductor processing. A flow rate of the hydrogencontaining precursor may be greater than or about 100 seem, and may be greater than or about 200 seem, greater than or about 300 seem, greater than or about 400 seem, greater than or about 500 seem, greater than or about 600 seem, greater than or about 700 seem, greater than or about 800 seem, greater than or about 900 seem, greater than or about 1,000 seem, or more. Similarly, the flow rate of the hydrogen-containing precursor may be less than or about 1,000 seem, and may be less than or about 900 seem, less than or about 800 seem, less than or about 700 seem, less than or about 600 seem, less than or about 500 seem, less than or about 400 seem, less than or about 300 seem, less than or about 200 seem, less than or about 100 seem, or less. The hydrogen-containing precursor may be provided with or include one or more diluents or carrier gases such as an inert gas or other gas delivered with the hydrogen-containing precursor.

[0048] A flow rate ratio of the hydrogen-containing precursor relative to the oxygencontaining precursor may be between about 500: 1 and about 1:500. Higher flow rate ratios will have a reduced amount of oxygen relative to hydrogen and may result in a reduced amount of oxidation of the metal-and-carbon-containing material 510. As such, subsequent removal of an oxidized portion of the metal-and-carbon-containing material 510 will result in a reduced thickness of the metal-and-carbon-containing material 510 being removed. As such, higher flow rate ratios will decrease the etch rate of the metal-and-carbon-containing material 510. Conversely, lower flow rate ratios may result in formation of carbon residue. The hydrogen-containing precursor may draw carbon out of the metal-and-carbon-containing material 510 as a volatile material that may be removed from the processing region. If there is not enough hydrogen-containing precursor present, carbon from the metal-and-carbon-containing material 510 may form as a residue on the structure 500 or elsewhere within the processing region. As such, the flow rate ratio of the hydrogen-containing precursor relative to the oxy gen-containing precursor may be less than or about 500: 1, and may be less than orabout 450: 1, less than or about 400: 1, less than or about 350: 1, less than or about 300: 1, less than or about 250: 1, less than or about 200: 1, less than or about 150: 1, less than or about 100: 1, less than or about 50: 1, less than or about 25: 1, less than or about 15: 1, less than or about 5: 1, or less. Alternatively, the flow rate ratio of the hydrogen-containing precursor relative to the oxy gen-containing precursor may be greater than or about 1:500, and may be greater than or about 1:450, greater than or about 1 :400, greater than or about 1:350, greater than or about 1 :300, greater than or about 1 :250, greater than or about 1 :200. greater than or about 1: 150, greater than or about 1:100, greater than or about 1:50, greater than or about 1:25, greater than or about 1 : 15, greater than or about 1 :5, or more. The flow rate ratio may also be maintained at any flow rate ratio within these ranges, within smaller ranges encompassed by these ranges, or between any of these ranges.

[0049] Whether plasma-enhanced or not at optional operation 410, the oxy gen-containing precursor and / or the hydrogen-containing precursor, or plasma effluents of the oxygencontaining precursor and / or the hydrogen-containing precursor, may be delivered to the processing region, where the precursor(s) and / or effluents may contact the substrate including exposed metal-and-carbon-containing material, such as an exposed region of metal carbide, at operation 415. The contacting may produce an oxidized material, such as an oxidized surface on the metal-and-carbon-containing material, such as by converting the exposed metal-and-carbon-containing material on the substrate. In some embodiments, when a plasma is formed, subsequent to the oxidation, the plasma may be extinguished, and the chamber may be purged. As illustrated in FIG. 5 A, the precursor(s) 515, or plasma effluents thereof, may be flowed to contact the metal-and-carbon-containing material 510. The contacting may oxidize at least a portion of the metal-and-carbon-containing material 510 to form a metaland-oxygen-containing material 520.

[0050] As illustrated in FIG. 5B, the contacting at operation 415 may produce a carbon-hydrogen-and-oxygen-containing material 525. Due to the processing conditions, contacting the substrate 505, including the metal-and-carbon-containing material 510, with the oxygencontaining precursor and / or the hydrogen-containing precursor or, if formed, plasma effluents thereof may volatilize carbon-hydrogen-and-oxy gen-containing material 525. The carbon-hydrogen-and-oxygen-containing material 525 may be pumped out of the processing region, leaving the metal-and-oxygen-containing material 520 for further processing.

[0051] After oxidizing at least a portion of the metal-and-carbon-containing material 510 to form a metal-and-oxygen-containing material 520, method 400 may include halting a flow of the oxygen-containing precursor and / or a flow of the hydrogen-containing precursor at optional operation 420. In embodiments, the processing region may be purged after halting the flow of the oxy gen-containing precursor and / or the flow of the hydrogen-containing precursor. Purging the processing region may remove any excess oxygen-containing precursor and / or hydrogen-containing precursor, as well as remove any residual carbon-hydrogen-and-oxygen-containing material 525.

[0052] Method 400 may include providing a halogen-containing precursor to the processing region of the semiconductor processing chamber at optional operation 420. The halogen-containing precursor may be provided after the flow of the oxygen-containing precursor and / or the flow of the hydrogen-containing precursor has been halted at optional operation 420. In some embodiments, the halogen-containing precursor may be flowed directly to contact the substrate 505, although in other embodiments a plasma may be formed of the halogen-containing precursor at optional operation 430 prior to contacting the substrate 505. Similar to the oxy gen-containing precursor and / or the hydrogen-containing precursor described above, the plasma may be formed remotely, or within a processing region of the semiconductor processing chamber in which the substrate 505 is housed. The halogencontaining precursor may be flowed through a remote plasma region of the processing chamber, such as region 215 described above, and a plasma may be formed of the halogencontaining precursor to produce plasma effluents. Although a substrate-level plasma may be produced, in some embodiments the plasma may be a remote plasma, which may protect exposed substrate materials from ion bombardment that may occur due to the substrate-level plasma. As illustrated in FIG. 5C, the substrate 505, including the metal-and-oxygen-containing material 520, may be contacted with the halogen-containing precursor 530 at operation 435. As illustrated in FIG. 5D, the contacting may remove the metal-and-oxygen-containing material 520. The underlying metal-and-carbon-containing material 510 that was not oxidized may serve as an etch stop layer.

[0053] In embodiments, the halogen-containing precursor may be a fluorine-containing precursor, a chlorine-containing precursor, or any other halogen-containing precursor. For example, the halogen-containing precursor may be or include, but is not limited to, boron trichloride (BCh), tungsten hexafluoride (WFe), or carbon tetrafluoride (CF4), or any other halogen-containing precursor used or useful in semiconductor processing. A flow rate of thehalogen-containing precursor may be greater than or about 100 seem, and may be greater than or about 200 seem, greater than or about 300 seem, greater than or about 400 seem, greater than or about 500 seem, greater than or about 750 seem, greater than or about 1,000 seem, greater than or about 2.500 seem, greater than or about 5,000 seem, greater than or about 10,000 seem, or more. Higher flow rates of the halogen-containing precursor may¬ increase etching of the metal-and-oxygen-containing material. However, precise control of the etching may begin to decrease at increased flow rates of the halogen-containing precursor. As such, to control the etching and prevent damage to other materials, the flow rate of the halogen-containing precursor may be less than or about 10,000 seem, and may be less than or about 7,500 seem, less than or about 5,000 seem, less than or about 2.500 seem, less than or about 1,000 seem, less than or about 750 seem, less than or about 500 seem, less than or about 500 seem, less than or about 400 seem, less than or about 300 seem, less than or about 200 seem, less than or about 100 seem, or less. The halogen-containing precursor may be provided with or include one or more diluents or carrier gases, such as an inert gas or other gas delivered with the halogen -containing precursor.

[0054] As illustrated in FIG. 4, subsequent to contacting the substrate 505 with the halogen-containing precursor or plasma effluents thereof, the operations of method 400 may be repeated. More specifically, following the containing at operation 435, method 400 may include providing the oxygen-containing precursor and / or the hydrogen-containing precursor again, such as at operation 405 of a second cycle of method 400. Subsequent cycles of method 400 may be the same as or different from previous cycles. In embodiments, operations 405-435 may be repeated for any number of cycles to remove a desired amount of the metal-and-carbon-containing material 510. For example, operations 405-435 may be repeated for a plurality of cycles, such as two cy cles, three cycles, four cycles, five cycles, ten cycles, twenty cycles, thirty cycles, forty cycles, fifty cycles, one hundred cycles, or more.

[0055] As illustrated in FIGS. 5A-5D. the oxidation at operations 405-415 may oxidize a portion of the metal-and-carbon-containing material 510 to form the metal-and-oxygen-containing material 520. The etching at operations 425-435 may then remove the metal-and-oxygen-containing material 520. While the degree of oxidation and thickness of the metal-and-oxygen-containing material 520 may be dependent on a variety of factors, such as precursors, temperature, and duration, a thickness of the metal-and-oxygen-containing material 520 may be less than or about 3 nm. The thickness of the metal-and-oxygen-containing material 520 may be substantially the same as the amount of metal-and-carbon-containing material 510 removed per cycle of method 400. In embodiments, the thickness of the metal-and-oxy gen-containing material 520, as well as the amount of metal-and-carbon-containing material 510 removed per cycle, may be less than or about 2.8 nm, than or about 2.6 nm, than or about 2.4 nm, than or about 2.2 nm, than or about 2.0 nm, less than or about 1.8 nm, than or about 1.6 nm, than or about 1.4 nm, than or about 1.2 nm, than or about 1.0 nm, or less. Additionally, the thickness of the metal-and-oxy gen-containing material 520, as well as the amount of metal-and-carbon-containing material 510 removed per cycle, may be greater than or about 1.0 nm, greater than or about 1.2 nm, greater than or about 1.4 nm, greater than or about 1.6 nm, greater than or about 1.8 nm, greater than or about 2.0 nm, greater than or about 2.2 nm, greater than or about 2.4 nm, greater than or about 2.6 nm, greater than or about 2.8 nm, greater than or about 3.0 nm, or more.

[0056] As noted previously, processing conditions may impact and facilitate etching according to the present technology. In embodiments, a temperature of the substrate, pedestal, or processing region may be maintained at greater than or about 200 °C, and may be performed at a temperature of greater than or about 225 °C, greater than or about 250 °C, greater than or about 275 °C, greater than or about 300 °C, greater than or about 325 °C. greater than or about 350 °C, greater than or about 375 °C, greater than or about 400 °C, greater than or about 450 °C, greater than or about 500 °C, greater than or about 550 °C, greater than or about 600 °C, or more. However, as temperature increases, which may¬ increase an amount of oxidation per cycle and the resultant amount of material etched, the oxidation operations may transition to producing higher density metal-and-oxygen-containing material 520, which may not be etched as easily. Accordingly, in some embodiments the method may be performed at a temperature of less than or about 600 °C, and may be performed at a temperature of less than or about 550 °C, less than or about 500 °C, less than or about 450 °C, less than or about 400 °C, less than or about 350 °C, less than or about 300 °C, less than or about 250 °C, or less. The temperature may also be maintained at any pressure within these ranges, within smaller ranges encompassed by these ranges, or between any of these ranges. Additionally, in embodiments that are plasma-enhanced or plasma-assisted and not purely thermal, a lower temperature may be needed to oxidize and etch. Furthermore, various operations of method 400 may be conducted at different temperatures. For example, the oxidation at operations 405-415 may be conducted at a higher or lower temperature than the etching at operations 425-435.

[0057] In addition to temperature, the pressure within the semiconductor processing chamber may also affect the operations performed as well as affect the rate at which the metal-and-carbon-containing material 510 is oxidized and subsequently etched. At higher pressures, the metal-and-carbon-containing material 510 may be oxidized to a greater degree, resulting in an increased thickness of the metal-and-oxygen-containing material 520 and an increased etch rate. Accordingly, in some embodiments, the pressure may be maintained at a pressure of greater than or about 1 Torr, and may be maintained at greater than or about 2 Torr, greater than or about 3 Torr, greater than or about 4 Torr, greater than or about 5 Torr, greater than or about 6 Torr, greater than or about 7 Torr, greater than or about 8 Torr, greater than or about 9 Torr, greater than or about 10 Torr, greater than or about 20 Torr, greater than or about 30 Torr, greater than or about 40 Torr, greater than or about 50 Torr, greater than or about 75 Torr, greater than or about 100 Torr, or higher. The pressure may also be maintained at any pressure within these ranges, within smaller ranges encompassed by these ranges, or between any of these ranges.

[0058] In the preceding description, for the purposes of explanation, numerous details have been set forth in order to provide an understanding of various embodiments of the present technology. It will be apparent to one skilled in the art, however, that certain embodiments may be practiced without some of these details, or with additional details.

[0059] Having disclosed several embodiments, it will be recognized by those of skill in the art that various modifications, alternative constructions, and equivalents may be used without departing from the spirit of the embodiments. Additionally, a number of well-known processes and elements have not been described in order to avoid unnecessarily obscuring the present technology. Accordingly, the above description should not be taken as limiting the scope of the technology. Additionally, methods or processes may be described as sequential or in steps, but it is to be understood that the operations may be performed concurrently, or in different orders than listed.

[0060] Where a range of values is provided, it is understood that each intervening value, to the smallest fraction of the unit of the lower limit, unless the context clearly dictates otherwise, betw een the upper and lower limits of that range is also specifically disclosed. Any narrower range between any stated values or unstated intervening values in a stated range and any other stated or intervening value in that stated range is encompassed. The upper and lower limits of those smaller ranges may independently be included or excluded inthe range, and each range where either, neither, or both limits are included in the smaller ranges is also encompassed within the technology, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included.

[0061] As used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise. Thus, for example, reference to “a precursor” includes a plurality of such precursors, and reference to “the layer” includes reference to one or more layers and equivalents thereof known to those skilled in the art, and so forth. “About” and / or “approximately” as used herein when referring to a measurable value such as an amount, a temporal duration, and the like, encompasses variations of ±20% or ±10%, ±5%, or ±0.1% from the specified value, as such variations are appropriate to in the context of the systems, devices, circuits, methods, and other implementations described herein. “Substantially” as used herein when referring to a measurable value such as an amount, a temporal duration, a physical attribute (such as frequency), and the like, also encompasses variations of ±20% or ±10%, ±5%, or ±0.1% from the specified value, as such variations are appropriate to in the context of the systems, devices, circuits, methods, and other implementations described herein.

[0062] Also, the words “comprise(s)”, “comprising”, “contain(s)”, “containing”, “include(s)”, and “including”, when used in this specification and in the following claims, are intended to specify the presence of stated features, integers, components, or operations, but they do not preclude the presence or addition of one or more other features, integers, components, operations, acts, or groups.

Claims

CLAIMS:

1. A semiconductor processing method comprising:providing an oxy gen-containing precursor to a processing region of a semiconductor processing chamber, wherein a substrate is housed within the processing region, and wherein a metal-and-carbon-containing material is disposed on the substrate;contacting the substrate with the oxygen-containing precursor, wherein the contacting the substrate oxidizes at least a portion of the metal-and-carbon-containing material to form a metal-and-oxy gen-containing material;providing a halogen-containing precursor to the processing region of the semiconductor processing chamber; andcontacting the metal-and-oxygen-containing material with the halogencontaining precursor, wherein the contacting the metal-and-oxygen-containing material etches the metal-and-oxygen-containing material.

2. The semiconductor processing method of claim 1, wherein the oxy gencontaining precursor comprises atomic oxygen (O), diatomic oxygen (O2), ozone (O3), nitrous oxide (N2O), nitrogen dioxide (NO2), water or steam (H2O), or hydrogen peroxide (H2O2).

3. The semiconductor processing method of claim 1, wherein a metal of the metal-and-carbon-containing material comprises titanium (Ti) or niobium (Nb).

4. The semiconductor processing method of claim 1, further comprising: providing a hydrogen-containing precursor to the processing region with the oxygen-containing precursor.

5. The semiconductor processing method of claim 4, wherein the hydrogen-containing precursor comprises diatomic hydrogen (H2), ammonia (NH3), water or steam (H2O), hydrogen peroxide (H2O2), diimide (N2H2), or hydrazine (N2H4).

6. The semiconductor processing method of claim 4, wherein a flow rate ratio of the hydrogen-containing precursor relative to the oxygen-containing precursor is between about 500: 1 and about 1 :500.

7. The semiconductor processing method of claim 1, further comprising:forming plasma effluents of the oxygen-containing precursor.

8. The semiconductor processing method of claim 1, further comprising: halting a flow of the oxygen-containing precursor prior to providing the halogen-containing precursor.

9. The semiconductor processing method of claim 1, wherein the halogen-containing precursor comprises boron trichloride (BCH), tungsten hexafluoride (WFe), or carbon tetrafluoride (CF4).

10. The semiconductor processing method of claim 1, further comprising: forming plasma effluents of the halogen-containing precursor.

11. The semiconductor processing method of claim 1 , wherein a temperature within the processing region is maintained at greater than or about 200 °C.

12. A semiconductor processing method comprising:i) providing an oxygen-containing precursor and a hydrogen-containing precursor to a processing region of a semiconductor processing chamber, wherein a substrate is housed within the processing region, and wherein a metal-and-carbon-containing material is disposed on the substrate;ii) contacting the substrate with the oxygen-containing precursor and hydrogen-containing precursor, wherein the contacting the substrate oxidizes at least a portion of the metal-and-carbon-containing material to form a metal-and-oxy gen-containing material;iii) halting a flow of the oxygen-containing precursor and / or a flow of the hydrogen-containing precursor;iv) providing a halogen-containing precursor to the processing region of the semiconductor processing chamber; andv) contacting the metal-and-oxy gen-containing material with the halogencontaining precursor, wherein the contacting the metal-and-oxygen-containing material etches the metal-and-oxygen-containing material, and wherein a temperature within the processing region is maintained at greater than or about 350 °C.

13. The semiconductor processing method of claim 12, wherein the metal -and-carbon-containing material comprises a titanium-aluminum-and-carbon-containing material (TiAlC) or a niobium-aluminum-and-carbon-containing material (NbAlC).

14. The semiconductor processing method of claim 12, wherein a flow rate ratio of the hydrogen-containing precursor relative to the oxy gen-containing precursor is between about 500: 1 and about 1 :500.

15. The semiconductor processing method of claim 12, wherein a thickness of the metal-and-oxygen-containing material is less than or about 3 nm.

16. The semiconductor processing method of claim 12, wherein a pressure within the processing region is maintained at greater than or about 1 Torr.

17. The semiconductor processing method of claim 12, further comprising: repeating operations i-v for a plurality of cycles.

18. A semiconductor processing method comprising:providing an oxy gen-containing precursor and a hydrogen-containing precursor to a processing region of a semiconductor processing chamber, wherein a substrate is housed within the processing region, and wherein a metal-and-carbon-containing material is disposed on the substrate;forming plasma effluents of the oxygen-containing precursor and the hydrogen-containing precursor;contacting the substrate with the plasma effluents of the oxy gen-containing precursor and the hydrogen-containing precursor, wherein the contacting the substrate oxidizes at least a portion of the metal-and-carbon-containing material to form a metal-and-oxygen-containing material;providing a halogen-containing precursor to the processing region of the semiconductor processing chamber; andcontacting the metal-and-oxygen-containing material with the plasma effluents of the halogen-containing precursor, wherein the contacting the metal-and-oxygen-containing material etches the metal-and-oxygen-containing material.

19. The semiconductor processing method of claim 18, wherein contacting the substrate with the plasma effluents of the oxygen-containing precursor and the hydrogencontaining precursor volatilizes a carbon-hydrogen-and-oxygen-containing material.

20. The semiconductor processing method of claim 18, wherein a temperature within the processing region is maintained at greater than or about 200 °C.

Images