Selective removal of ruthenium-containing material

Abstract

To provide a method for selective removal of ruthenium-containing material by etching.SOLUTION: An etching method includes flowing an oxygen-containing precursor into a processing region of a semiconductor processing chamber and contacting a substrate contained within the processing region with the oxygen-containing precursor. The substrate includes an exposed region of ruthenium, and the contacting produces ruthenium tetroxide. The method also includes evaporating the ruthenium tetroxide from a surface of the exposed region of ruthenium, leaving behind a quantity of ruthenium oxide. The method further includes contacting the ruthenium oxide with a hydrogen-containing precursor and removing the ruthenium oxide.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of and priority to U.S. patent application Ser. No. 17 / 240,149, filed April 26, 2021, and entitled "SELECTIVE REMOVAL OF RUTHENIUM-CONTAINING MATERIALS," the contents of which are incorporated by reference in their entirety into this specification for all purposes.

[0002]

[0002] The present technology relates to semiconductor processes and equipment. More specifically, the present technology relates to selectively etching ruthenium-containing structures. [Background technology]

[0003]

[0003] Integrated circuits are made possible by processes that produce intricately patterned layers of material on a substrate surface. Creating patterned materials on a substrate requires a controlled method for removing exposed material. Chemical etching is used for a variety of purposes, including transferring a pattern of photoresist to an underlying layer, thinning a layer, or narrowing the lateral dimensions of features already present on a surface. It is often desirable to have an etching process that etches some materials faster than others, for example, to facilitate the pattern transfer process. Such an etching process is said to be selective to the first material. Due to the diversity of materials, circuits, and processes, etching processes have been developed that are selective to a variety of materials.

[0004]

[0004] Etching processes may be referred to as wet or dry based on the materials used in the process. For example, wet etching may preferentially remove some oxide dielectrics over other dielectrics and materials. However, wet processes have difficulty penetrating some constrained trenches and may sometimes deform the remaining materials. Dry etching is performed in a local plasma formed within the processing area of ​​the substrate, but is able to penetrate more constrained trenches and causes less deformation of the fragile remaining structures. However, local plasmas may damage the substrate through the generation of electric arcs when they discharge.

[0005]

[0005] Thus, there is a need for improved systems and methods that can be used to manufacture high quality devices and structures. The present technology addresses these and other needs. Summary of the Invention

[0006]

[0006] An exemplary etching method may include flowing an oxygen-containing precursor into a processing region of a semiconductor processing chamber. The method may include contacting a substrate contained within the processing region with the oxygen-containing precursor. The substrate may include an exposed region of ruthenium, and the contacting may produce ruthenium tetroxide. The method may include evaporating the ruthenium tetroxide from a surface of the exposed region of ruthenium. A quantity of ruthenium oxide may remain. The method may include contacting the ruthenium oxide with a hydrogen-containing precursor. The method may include removing the ruthenium oxide.

[0007]

[0007] In some embodiments, the method may further include forming a plasma from the oxygen-containing precursor. The processing region is flowed with plasma effluent. The temperature in the processing region may be maintained at about 100° C. or greater. The temperature in the processing region may be maintained at about 150° C. or less. The hydrogen-containing precursor may be or may include diatomic hydrogen. The method may include contacting the substrate with the hydrogen-containing precursor prior to flowing the oxygen-containing precursor. The hydrogen-containing precursor may expose areas of ruthenium. The processing region may be maintained plasma free throughout the etching method. Additional ruthenium may be exposed by removing the oxidized ruthenium. The method may be repeated for additional cycles. The ruthenium may be selectively removed relative to exposed areas of silicon oxide, titanium oxide, or tungsten oxide. The pressure in the semiconductor processing chamber may be maintained at about 1 Torr or greater.

[0008]

[0008] Some embodiments of the present technology may include an etching method. The method may include flowing an oxygen-containing precursor into a processing region of a semiconductor processing chamber. The method may include contacting a substrate contained within the processing region with the oxygen-containing precursor. The substrate may include an exposed region of ruthenium. The contacting may produce ruthenium tetroxide. The method may include performing a particle treatment with an inert precursor in the processing region of the semiconductor processing chamber. The method may include contacting the ruthenium tetroxide with the inert precursor. The method may include removing the ruthenium tetroxide.

[0009]

[0009] In some embodiments, the method may include forming a plasma from an oxygen-containing precursor in a process region or a remote plasma region of a semiconductor processing chamber. The pressure in the semiconductor processing chamber may be maintained at about 25°C or less. The plasma may be formed from an inert precursor. The plasma power used to form the plasma from the inert precursor may be maintained at about 500W or less. Additional ruthenium may be exposed by removing ruthenium tetroxide. The method may be repeated for additional cycles. The method may include contacting the substrate with a hydrogen-containing precursor prior to flowing the oxygen-containing precursor. The hydrogen-containing precursor may expose a region of ruthenium.

[0010]

[0010] Some embodiments of the present technology may include an etching method. The method may include contacting a substrate disposed in a processing region of a semiconductor processing chamber with a hydrogen-containing precursor. The contacting may expose ruthenium metal on the substrate. The method may include flowing an oxygen-containing precursor into a processing region of the semiconductor processing chamber. The method may include contacting the exposed ruthenium metal on the substrate with the oxygen-containing precursor. The contacting may produce ruthenium tetroxide. The method may include evaporating the ruthenium tetroxide from the surface of the ruthenium metal. In some embodiments, a temperature in the processing region may be maintained at about 150°C or less. The method may include forming a plasma from the oxygen-containing precursor in the semiconductor processing chamber. The method may include repeating the method for at least one additional cycle.

[0011]

[0011] Such techniques may provide many advantages over conventional systems and techniques. For example, the process may enable precisely controlled dry etching to be performed to remove discreet layers of ruthenium-containing materials. In addition, the process may selectively remove ruthenium-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 following description and accompanying drawings.

[0012]

[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. [Brief description of the drawings]

[0013] [Figure 1] 1 illustrates a top view of one embodiment of an exemplary processing system in accordance with some embodiments of the present technique. [Figure 2A]

[0014] 1 shows a schematic cross-sectional view of an exemplary processing chamber in accordance with some embodiments of the present technique. [Figure 2B]

[0015] 2B shows a detailed view of a portion of the processing chamber shown in FIG. 2A, in accordance with some embodiments of the present technique. [Diagram 3]

[0016] FIG. 1 illustrates a bottom view of an exemplary showerhead in accordance with some embodiments of the present technique. [Figure 4]

[0017] 1 illustrates exemplary steps of a method according to some embodiments of the present technology. [Diagram 5]

[0018] 1A-C show schematic cross-sectional views of a material being etched according to some embodiments of the present technique. [Figure 6]

[0019] 1 illustrates exemplary steps of a method according to some embodiments of the present technology. [Figure 7]

[0020] 1A-C show schematic cross-sectional views of a material being etched according to some embodiments of the present technique. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014]

[0021] Some drawings are included as schematics. It should be understood that the drawings are for illustrative purposes and should not be considered to scale unless expressly stated to be to scale. Furthermore, as schematics, the drawings are provided to aid in understanding and may not include all aspects or information compared to a realistic depiction and may include additional or emphasized material for illustrative purposes.

[0015]

[0022] In the accompanying drawings, similar components and / or features may have the same reference numbers. Furthermore, various components of the same type may be distinguished according to the reference numbers, with a letter distinguishing between the similar components. If only a first reference number is used in this specification, the description is applicable to any of the similar components having the same first reference number, regardless of the letter.

[0016]

[0023] As electronic devices continue to shrink in size, moving to future technology nodes has revealed challenges with scaling of semiconductor materials. For example, copper has been used as an interconnect or wiring material based on the metal's relatively low resistance. However, as critical dimensions continue to shrink, it has been shown that the resistance of copper increases. For relatively large line widths, copper can maintain low resistance to maintain device performance. As wiring shrinks below 50 nm, the resistance of copper can increase dramatically due to surface scattering. Scattering can relate to the electrons traveling with the current flow. When electrons reach a sidewall, they can lose momentum in a sense and the effective resistance begins to increase. At lower line widths, the effective electron mean free path decreases, scattering increases, and for copper, the resistance can increase by more than five times over the standard bulk resistance.

[0017]

[0024] Because copper is characterized by low resistivity, the material may still outperform other materials at larger line widths. When moving to smaller line widths, copper's resistance increases dramatically so that other materials may begin to outperform copper. For example, ruthenium is characterized by a less dramatic increase in resistance during device scaling, which may be smaller than copper at a given line width. However, ruthenium is often treated with chlorine-based etching processes, which may increase the surface roughness of ruthenium. At material interfaces, this increased roughness may adversely affect resistance by further increasing scattering.

[0018]

[0025] The present technology may overcome these problems by performing an etching process that removes ruthenium in individual layers and may be performed selectively with respect to surrounding materials, including some oxide materials. By removing ruthenium by generating or releasing oxidized materials, the present technology may provide an etching process that provides a smoother interface surface compared to many conventional chemical etches. While 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 several other structures that may benefit from aspects of the present technology. Thus, the present technology should not be considered limited to use with any particular process or material alone. Additionally, while an exemplary chamber is described to provide a foundation for the present technology, it should be understood that the present technology may be performed in virtually any semiconductor processing chamber that may enable the steps described.

[0019]

[0026] FIG. 1 illustrates a top view of one embodiment of a deposition, etch, bake, and cure chamber processing system 100, according to an embodiment. In the figure, a pair of front-opening unified pods 102 deliver substrates of various sizes that are received by a robot arm 104 and placed in a low pressure holding area 106 before being placed in one of the substrate processing chambers 108a-108f, located in tandem sections 109a-109c. A second robot arm 110 may be used to transfer substrate wafers from the holding area 106 to and from the substrate processing chambers 108a-108f. Each substrate processing chamber 108a-108f may be equipped to perform several substrate processing steps, including cyclic layer deposition, atomic layer deposition, chemical vapor deposition, physical vapor deposition, etching, precleaning, degassing, orientation, and other substrate processes, as well as dry etching processes as described herein.

[0020]

[0027] The substrate processing chambers 108a-f may include one or more system components for depositing, annealing, curing, and / or etching a dielectric film on a substrate wafer. In one configuration, two pairs of processing chambers (e.g., 108c-d and 108e-f) may be used to deposit a dielectric material on a substrate, and a 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 a substrate. Any one or more of the processes described may be performed in one or more chambers separate from the manufacturing system shown in different embodiments. It will be appreciated that further configurations of deposition, etch, annealing, and curing chambers for the dielectric film are contemplated by the system 100.

[0021]

[0028] 2A shows a cross-sectional view of an exemplary processing chamber system 200 having a divided plasma generation region within the processing chamber. During etching of a film (e.g., titanium nitride, tantalum nitride, tungsten, silicon, polysilicon, silicon oxide, silicon nitride, silicon oxynitride, silicon oxycarbide, etc.), process gases may be flowed through gas injection assembly 205 into a first plasma region 215. A remote plasma system 201 may optionally be included in the system to process a first gas that then travels through gas injection assembly 205. Injection assembly 205 may include two or more separate gas supply channels, and if included, a second channel may bypass remote plasma system 201.

[0022]

[0029] The cooling plate 203, faceplate 217, ion suppressor 223, showerhead 225, and pedestal 265 or substrate support on which the substrate 255 is disposed are shown and may each be included according to an embodiment. The pedestal 265 may have heat exchange channels through which a heat exchange fluid flows to control the temperature of the substrate. The heat exchange channels may operate to heat and / or cool the substrate or wafer during processing operations. The wafer support platter of the pedestal 265, which may comprise aluminum, ceramic, or a combination thereof, may also be resistively heated using embedded resistive heating elements to reach relatively high temperatures, such as up to about 100° C. to about 1100° C. or higher.

[0023]

[0030] The face plate 217 may be pyramidal, conical, or another similar structure that is narrow at the top and widens toward the bottom. The face plate 217 may also be flat, as shown, or may include multiple through channels used to distribute process gases. Plasma generating gases and / or plasma excited species may pass through multiple holes, shown in FIG. 2B, in the face plate 217 for more uniform delivery to the first plasma region 215, depending on the use of the remote plasma system 201.

[0024]

[0031] An exemplary configuration may include gas inject assembly 205 opening into gas feed region 258 separated from first plasma region 215 by faceplate 217 such that gas / species may flow into first plasma region 215 through holes in faceplate 217. Structural and operational features may be selected to prevent bulk backflow of plasma from first plasma region 215 into feed region 258, gas inject assembly 205, and fluid delivery system 210. Faceplate 217 (or conductive top of the chamber) and showerhead 225 are shown with insulating ring 220 disposed between their features, allowing an AC potential to be applied to faceplate 217 relative to showerhead 225 and / or ion suppressor 223. Insulating ring 220 may be disposed between faceplate 217 and showerhead 225 and / or ion suppressor 223 to form a capacitively coupled plasma in the first plasma region. In addition, baffles may be positioned within first plasma region 215 or otherwise coupled to gas injector assembly 205 to affect the flow of fluid through gas injector assembly 205 into this region.

[0025]

[0032] The ion suppressor 223 may include a plate or other geometry that defines a number of apertures throughout the structure. The number of apertures is configured to suppress the movement of ionic charged species out of the first plasma region 215 while allowing uncharged neutral or radical species to pass through the ion suppressor 223 and into the activated gas supply region between the suppressor and the showerhead. In an embodiment, the ion suppressor 223 may comprise a perforated plate having various aperture configurations. These uncharged species may include highly reactive species that are carried with a less reactive carrier gas through the apertures. As discussed above, the movement of ionic species through the apertures may be reduced and in some cases may be completely suppressed. Controlling the amount of ionic species that pass through the ion suppressor 223 may advantageously provide improved control over the gas mixture that is brought into contact with the underlying wafer substrate, thereby providing improved control over the deposition and / or etching characteristics of the gas mixture. For example, adjusting the ion concentration of the gas mixture may significantly change its etch selectivity, e.g., SiNx:SiOx etch ratio, Si:SiOx etch ratio, etc. In alternative embodiments in which deposition is performed, the balance of conformal to flowable deposition for the dielectric material may also be shifted.

[0026]

[0033] The plurality of apertures in the ion suppressor 223 may be configured to control the passage of active gas (i.e., ionic, radical, and / or neutral species) through the ion suppressor 223. For example, the aspect ratio of the apertures (i.e., diameter to length of the aperture) and / or the geometry of the apertures may be controlled to reduce the flow rate of ionic charged species in the active gas passing through the ion suppressor 223. The apertures in the ion suppressor 223 may include a tapered section facing the plasma excitation region 215 and a cylindrical section facing the showerhead 225. The cylindrical section may be shaped and sized to control the flow of ionic species passing to the showerhead 225. As an additional means for controlling the flow of ionic species through the ion suppressor 223, an adjustable electrical bias may be applied to the ion suppressor 223.

[0027]

[0034] The ion suppressor 223 may function to reduce or eliminate the amount of ionic charged species that travel from the plasma generating region to the substrate. Uncharged neutral and radical species may further pass through the openings of the ion suppressor to react with the substrate. It should be noted that in embodiments, complete removal of ionic charged species in the reaction region surrounding the substrate may not be performed. In certain cases, ionic species are intended to reach the substrate to perform etching and / or deposition processes. In these cases, the ion suppressor may help control the concentration of ionic species in the reaction region at a process-supporting level.

[0028]

[0035] The showerhead 225, in combination with the ion suppressor 223, may allow the plasma present in the first plasma region 215 to avoid direct excitation of gases in the substrate processing region 233, but still allow excited species to migrate from the chamber plasma region 215 into the substrate processing region 233. In this way, the chamber may be configured to prevent the plasma from contacting the substrate 255 being etched. This advantageously protects various intricate structures and films patterned on the substrate, which may be damaged, displaced, or distorted if the generated plasma comes into direct contact. In addition, when the plasma is allowed to contact the substrate or approach the substrate level, the etch rate of oxide species may increase. Thus, if the exposed area of ​​material is an oxide, this material may be further protected by keeping the plasma away from the substrate.

[0029]

[0036] The processing system may further include a power supply 240 electrically coupled to the processing chamber. The power supply 240 provides power to the face plate 217, the ion suppressor 223, the showerhead 225, and / or the pedestal 265 to generate a plasma in the first plasma region 215 or the processing region 233. The power supply may be configured to provide an adjustable amount of power to the chamber depending on the process being performed. Such a configuration may allow for the use of an adjustable plasma in the process being performed. Unlike remote plasma units that often present an on or off function, an adjustable plasma may be configured to provide a specific amount of power to the plasma region 215. This may allow for the development of specific plasma characteristics that may separate precursors in a specific way and enhance the etch profile produced by these precursors.

[0030]

[0037] A plasma may be ignited in either the chamber plasma region 215 above the showerhead 225 or in the substrate processing region 233 below the showerhead 225. For example, a plasma may exist in the chamber plasma region 215 to generate radical precursors from an inflow of a fluorine-containing precursor or other precursor. An alternating voltage, typically in the radio frequency ("RF") range, is applied between a conductive top portion of the processing chamber, such as the faceplate 217, and the showerhead 225 and / or ion suppressor 223 to ignite a plasma in the chamber plasma region 215 during deposition. The RF power source may generate a high RF frequency of 13.56 MHz, although other frequencies may be generated alone or in combination with the 13.56 MHz frequency.

[0031]

[0038] FIG. 2B shows a detailed view 253 of features that affect process gas distribution through faceplate 217. As shown in FIGS. 2A and 2B, the intersection of faceplate 217, cooling plate 203, and gas injector assembly 205 defines a gas delivery region 258. Gas delivery region 258 may be supplied with process gas from gas injector assembly 205. Gas may fill gas delivery region 258 and flow through apertures 259 in faceplate 217 to first plasma region 215. Apertures 259 may be configured to direct flow in substantially one direction. This allows process gas to flow into processing region 233 but may be partially or completely prevented from flowing back into gas delivery region 258 after traversing faceplate 217.

[0032]

[0039] A gas delivery assembly such as the showerhead 225 used in the processing chamber section 200 may also be referred to as a dual channel showerhead, and is shown in more detail in the embodiment depicted in Figure 3. The dual channel showerhead may provide an etching process that allows for separation of etchants outside the processing region 233, resulting in limited interaction with the chamber components and each other, before being delivered into the processing region.

[0033]

[0040] The showerhead 225 can include an upper plate 214 and a lower plate 216. The plates can be coupled together to define a space 218 between the plates. The plates can be coupled to provide a first fluid channel 219 through the upper and lower plates and a second fluid channel 221 through the lower plate 216. The formed channels can be configured to provide fluid access from the space 218 through the lower plate 216 only via the second fluid channel 221, and the first fluid channel 219 can be fluidly isolated from the space 218 between the plates and the second fluid channel 221. The space 218 can be fluidly accessible through a side of the showerhead 225.

[0034]

[0041] 3 is a bottom view of a showerhead 325 for use in a processing chamber, according to an embodiment. The showerhead 325 may correspond to the showerhead 225 shown in FIG. 2A. The through-holes 365, which represent the first fluid channels 219, may have a number of shapes and configurations to control and influence the flow of precursors through the showerhead 225. Small holes 375, which represent the second fluid channels 221, may be approximately evenly distributed above the surface of the showerhead, even among the through-holes 365. Compared to other configurations, these small holes 375 may help provide more uniform mixing of the precursors as they flow out of the showerhead.

[0035]

[0042] The aforementioned chambers may be used in performing the exemplary method, including the etching method, although any number of chambers may be configured to perform one or more aspects used in the embodiments of the present technology. Referring to FIG. 4, exemplary steps in a method 400 according to an embodiment of the present technology are shown. The method 400 may include one or more operations before the start of the method, including front-end processing, deposition, etching, polishing, cleaning, or any other operations that may be performed before the described operations. The method may include several optional steps. These steps may or may not be specifically associated with some embodiments of the method according to the embodiments of the present technology. For example, many of the steps are described to provide a broader range of processes to be performed, but are not critical to the technology or may be performed by alternative methods as further described below. The method 400 may describe the steps shown generally in FIGS. 5A-5C, examples of which will be described in conjunction with the steps of the method 400. It should be understood that the figures show only partial schematic views, and the substrate may include any number of additional materials and features having various properties and aspects as shown in the figures.

[0036]

[0043] Method 400 may or may not include optional steps for developing the semiconductor structure into a particular manufacturing process. It should be understood that method 400 may be performed on any number of semiconductor structures or substrates 505 (shown in FIG. 5A), including the exemplary structures in which a ruthenium-containing material removal process may be performed. The exemplary semiconductor structures may include trenches, vias, or other recessed features that may include one or more exposed materials. For example, the exemplary substrate may include silicon or some other semiconductor substrate material, as well as an interlayer dielectric material in which a recess, trench, via, or isolation structure may be formed. The material exposed at any point during the etching process may be or include a metal material, one or more dielectric materials, a contact material, a transistor material, or any other material that may be used in semiconductor processing.

[0037]

[0044] For example, while shown as a general layer, FIG. 5A may show a layer of ruthenium 510 on a substrate 505 or some other semiconductor material. While the remaining disclosure refers to ruthenium, it should be understood that the ruthenium material 510 may also be ruthenium oxide, whether a native oxide or an oxidized surface. The substrate 505 may show a dielectric material overlying one or more other structures on the substrate. It should be understood that any number of materials may be formed below the depicted structures. In some embodiments, the dielectric material may be or include silicon oxide, or any other oxide or nitride that may be patterned. The noted structures are not intended to be limiting, and it should be understood that any of a variety of other semiconductor structures that include ruthenium-containing materials or other metal-containing materials are similarly encompassed. Other exemplary structures may include two-dimensional and three-dimensional structures common in semiconductor manufacturing. In these structures, a ruthenium-containing material, such as ruthenium metal or ruthenium oxide, will be removed relative to one or more other materials, and the present technique may selectively remove the ruthenium-containing material relative to other exposed materials, such as silicon oxide, titanium oxide, tungsten oxide, and any of the other materials discussed elsewhere, among a variety of other exposed materials. In addition, while high aspect ratio structures may benefit from the present technique, the technique may be equally applicable to lower aspect ratios and any other structures.

[0038]

[0045] Method 400 may be performed in embodiments of the present technology to remove exposed ruthenium-containing materials. The method may include specific steps for the removal of ruthenium metal. The remaining disclosure routinely discusses ruthenium and ruthenium oxide, but it should be understood that other metals may be similarly treated by some embodiments of the present technology. In some embodiments, the method may include a multi-step etching process that may control the etching of ruthenium relative to other exposed materials, such as dielectric materials, e.g., silicon oxide, as well as any underlying contact materials, such as conductive materials used within the structure that may be coupled with one or more device structures.

[0039]

[0046] As previously mentioned, a certain amount of oxidation may be present on the surface of the ruthenium 510 and may be removed before proceeding with the etching process. Whether the oxidation is native or residual oxidation from previous processing, including previous cycles of method 400, removing the oxidation may facilitate the formation of certain oxide species, which may enable increased removal of ruthenium in some embodiments of the present technique. Thus, in some embodiments, method 400 may include contacting the substrate with a hydrogen-containing precursor in optional step 405. The hydrogen may reduce oxidation producing water vapor that may be purged from the chamber, leaving the ruthenium surface exposed on the substrate.

[0040]

[0047] The method 400 may include, in step 410, flowing an oxygen-containing precursor into a semiconductor processing chamber housing the described substrate. In some embodiments, the oxygen-containing precursor may be flowed directly into contact with the substrate, but in some embodiments, a plasma may be formed from the oxygen-containing precursor. The plasma may be formed remotely or within a processing region of the semiconductor processing chamber housing the substrate. The oxygen-containing precursor may be flowed through a remote plasma region of the processing chamber, such as region 215 described above. A plasma may be formed from the oxygen-containing precursor to generate plasma effluents. A substrate-level plasma may be generated, but in some embodiments, the plasma is a remote plasma, which may protect exposed substrate material from ion bombardment that may result from the substrate-level plasma.

[0041]

[0048] Whether plasma enhanced or not, an oxygen-containing precursor or plasma effluent of an oxygen-containing precursor may be provided to a substrate processing region in step 410. In step 415, the effluent may contact a semiconductor substrate containing exposed ruthenium-containing material, such as an exposed area of ​​ruthenium. The contact may produce an oxide surface on the ruthenium or an oxide material, such as a ruthenium oxide material, such as by converting the exposed ruthenium on the substrate. In some embodiments, once the plasma is formed, the oxidation may then occur, the plasma may be extinguished, and the chamber may be purged. As shown in FIG. 5A, the oxygen material, or oxygen plasma effluent 515, may be flowed into contact with the exposed ruthenium material 510. This may convert the exposed surface of the ruthenium 510 to a ruthenium oxide material 520, as shown in FIG. 5B.

[0042]

[0049] The present technique may control one or more conditions during oxidation to produce a specific oxide species of ruthenium. For example, in some embodiments of the present technique, a contacting step may be performed to produce a certain amount of ruthenium tetroxide along the surface of the substrate. By producing ruthenium tetroxide instead of ruthenium dioxide, the present technique may be able to selectively remove ruthenium above many other exposed materials on the substrate. For example, unlike ruthenium dioxide, which has a dense structure that may limit removal during processing, ruthenium tetroxide may be characterized by a relatively low boiling point. Thus, when oxidation of ruthenium may be performed to produce ruthenium tetroxide, the produced material may be evaporated from the surface of the substrate. Thus, in some embodiments, the method 400 may include evaporating at least a portion of the ruthenium tetroxide from the substrate in step 420 to remove volatile material from the underlying ruthenium or substrate material. As shown in FIG. 5B, ruthenium tetroxide 525 may be evaporated from the surface of the structure due to processing conditions.

[0043]

[0050] For example, the method 400 may be performed at a temperature sufficient to evaporate the generated ruthenium tetroxide from the surface. Thus, in some embodiments, the method 400 is performed at a temperature of about 60° C. or more, and may be performed at a temperature of about 80° C. or more, about 100° C. or more, about 110° C. or more, about 120° C. or more, about 130° C. or more, about 140° C. or more, about 150° C. or more, or more. However, as the temperature increases, the oxidation process transitions to generate higher density ruthenium dioxide, which may not evaporate due to its significantly higher boiling point. Thus, in some embodiments, the method is performed at a temperature below about 170° C., and may be performed at a temperature below about 160° C., below about 150° C., or less. By maintaining a temperature within a window high enough to allow ruthenium tetroxide to evaporate, the present technique may enable ruthenium to be removed from the substrate while maintaining a temperature low enough to limit or prevent the generation of ruthenium dioxide.

[0044]

[0051] Advantageously, the method may selectively remove ruthenium while essentially or completely preserving other exposed materials, including silicon oxide, titanium oxide, tungsten oxide, or other materials, where many other materials do not evaporate at the operating temperatures of method 400, such as, for example, between about 100° C. and about 150° C. Exposed metal may also be preserved by method 400, which may only oxidize the surface of the material but may not otherwise etch the material. As noted above, in some embodiments, method 400 may not include plasma enhancing an oxygen-containing precursor, and the method may be performed while maintaining a plasma-free environment. This may further limit damage or removal of other exposed materials in some embodiments.

[0045]

[0052] Following the oxidation step, the supply of oxygen material may be stopped. Based on the oxidation of ruthenium, residual ruthenium oxide may remain after the evaporation of ruthenium tetroxide and may not be a volatile species. This may limit the etching from proceeding continuously or may slow down the etching process. Thus, in some embodiments, the method may include contacting the residual ruthenium oxide with a hydrogen-containing precursor before continuing the supply of oxygen-containing precursor. This may produce volatile water vapor that may be purged from the process chamber and reduce the surface to ruthenium. As shown in FIG. 5C, the hydrogen-containing material 520 may flow to the residual ruthenium oxide material 527, and the surface may be reduced to ruthenium or the oxidized material may be removed but to a lesser extent, or the removal step may be completed, as shown in FIG. 5A. The contacting may be similar or identical to the hydrogen pretreatment, as previously described in optional step 405. Thus, in some embodiments, the method may begin and / or end with a hydrogen treatment. The process may be repeated in one or more cycles to remove additional layers of ruthenium from the substrate.

[0046]

[0053] The precursors during each of the two-step process include oxygen-containing precursors, and in some embodiments, may include any oxygen-containing material. For example, non-limiting oxygen-containing precursors may include diatomic oxygen, ozone, water, alcohol, hydrogen peroxide, nitrous oxide, or any other oxygen-containing material. The hydrogen-containing material may be or include diatomic hydrogen, or any other hydrogen-containing material, including, for example, hydrogen-containing materials that include oxygen or nitrogen. The precursors may also be flowed with any number of additional precursors or carrier gases, including nitrogen, argon, helium, or any number of additional materials, although in some embodiments, the precursors may be limited to control side reactions or other aspects that may affect selectivity.

[0047]

[0054] As previously mentioned, process conditions can influence and facilitate etching according to the present technique. In addition to temperature, the pressure in the chamber can also affect the process performed and at what temperature ruthenium tetroxide is generated from the ruthenium surface. Thus, in some embodiments, the pressure is maintained at a pressure of about 1 Torr or greater, and can be maintained at about 2 Torr or greater, about 3 Torr or greater, about 4 Torr or greater, about 5 Torr or greater, about 6 Torr or greater, about 7 Torr or greater, about 8 Torr or greater, about 9 Torr or greater, about 10 Torr or greater, or greater. The pressure can also be maintained at any pressure within these ranges, smaller ranges encompassed by these ranges, or between any of these ranges.

[0048]

[0055] The present technology may also provide additional mechanisms for removing ruthenium from semiconductor substrates. Referring to Figure 6, a method 600 for etching ruthenium-containing materials according to an embodiment of the present technology is shown. Method 600 may describe steps shown generally in Figures 7A-7C. These figures will be described in conjunction with the steps of method 600. It should be understood that the figures are only partial schematic views and that the substrate may include any number of additional materials and features having various properties and aspects as shown in the figures.

[0049]

[0056] Method 600 may or may not include optional steps for developing the semiconductor structure into a particular manufacturing process. Additionally, method 600 may include any or all of the steps and any of the process conditions previously described with respect to method 400. It is understood that method 600 may be performed on any number of semiconductor structures or substrates 705 as shown in FIG. 7A and as described above with respect to method 400. With respect to the substrate including a layer of ruthenium-containing material 710, such as ruthenium metal, exposed on the substrate, any substrate previously described or used in semiconductor processing may be included.

[0050]

[0057] Similar to method 400, the ruthenium may have residual oxidized material, native oxide, or other features that may be removed in optional step 605, which may be as discussed above with respect to step 405. In step 610, an oxygen-containing precursor may be flowed into the process chamber. As described above in step 410, the oxygen-containing precursor may be plasma enhanced or not, and the oxygen-containing precursor may be any of the materials previously described. The oxygen-containing precursor, or a plasma effluent of the oxygen-containing precursor, may contact the substrate in step 615 and contact the exposed ruthenium. As shown in FIG. 7A, the oxygen-containing material 715 may contact the ruthenium 710. As shown in FIG. 7B, the oxygen-containing material may be provided to generate ruthenium tetroxide 720 on the surface of the ruthenium.

[0051]

[0058] While method 400 may provide a process by which volatile ruthenium tetroxide can be generated from a ruthenium material, method 600 may be performed to remove a controlled and separate ruthenium layer by maintaining the ruthenium tetroxide on the surface of the substrate, as shown in FIG. 7B. For example, method 600 may be performed at any of the process conditions described above, such as in connection with method 400. Additionally, in some embodiments, method 600 may be performed at a temperature below the vaporization temperature of ruthenium tetroxide. For example, method 600 may be performed at a temperature of about 50° C. or less, and may be performed at a temperature of about 40° C. or less, about 30° C. or less, about 25° C. or less, about 20° C. or less, about 15° C. or less, about 10° C. or less, about 5° C. or less, about 0° C. or less, or less. This allows a layer of ruthenium tetroxide to form and remain over the surface of the ruthenium.

[0052]

[0059] In step 620, the method may include performing a particle treatment using an inert precursor. A plasma may be formed in a remote portion of the semiconductor processing chamber or may be formed within the processing region of the semiconductor processing chamber. In some embodiments, an inert precursor such as argon, helium, or some other material may be used and delivered to the substrate, although any number of reactive materials may be used. For example, a bias may be engaged to direct the plasma effluent to the substrate surface, which may act as a cathode in the chamber, for example. The plasma effluent may contact ruthenium tetroxide. The plasma effluent may provide sufficient energy to release ruthenium tetroxide from the surface of the ruthenium and remove the material in step 625. As shown in FIG. 7C, the inert effluent 725 may contact the substrate surface, release ruthenium tetroxide 730 from the surface, and be purged from the processing chamber. This may remove a layer of ruthenium from the substrate and expose additional ruthenium.

[0053]

[0060] By maintaining a layer of ruthenium tetroxide on the surface, further oxidation can be controlled, allowing for a layered etching process. The method can be repeated any number of times to remove the desired amount of ruthenium. As mentioned above, additional oxidized material, which may not be ruthenium tetroxide, can remain on the substrate surface after the releasing step. An additional step can be performed as described above, including contacting the remaining material with hydrogen or a hydrogen release to reduce the surface to ruthenium. Thus, as described above and for any of the methods according to the present technology, the cycles may or may not include a hydrogen treatment during each cycle, or some cycles may include a hydrogen treatment while other cycles may proceed directly with additional oxygen exposure.

[0054]

[0061] When plasma effluents are utilized during one or both of the steps, such as oxygen-containing precursors and / or inert plasma generation, the plasma power may be maintained at about 500 W or less. By maintaining a lower plasma power, sputtering of the underlying ruthenium is controlled and interactions are limited to superficial physical reactions, which may better limit the extent of removal through the ruthenium-containing material. Thus, in some embodiments of any of the methods discussed in which a plasma is formed, the plasma power may be maintained at about 450 W or less, about 400 W or less, about 350 W or less, about 300 W or less, about 250 W or less, about 200 W or less, about 150 W or less, about 100 W or less, or less. By performing an etching process according to an embodiment of the present technology, a substantially self-limiting removal process is performed to precisely remove ruthenium, which may be performed at a temperature that may limit the removal of additional exposed material across the substrate.

[0055]

[0062] In the preceding description, for purposes of explanation, numerous details have been set forth in order to provide an understanding of various embodiments of the present technology. However, it will be apparent to one skilled in the art that particular embodiments may be practiced without some of these details or with additional details.

[0056]

[0063] Although several embodiments have been disclosed, those skilled in the art will recognize that various modifications, alternative structures, and equivalents may be used without departing from the spirit of the embodiments. Moreover, some well-known processes and elements have not been described to avoid unnecessarily obscuring the present technology. Thus, the above description should not be construed as limiting the scope of the present technology. In addition, although a method or process may be described in a sequence or steps, it should be understood that the steps may be performed simultaneously or in a different order than listed.

[0057]

[0064] Where a range of values ​​is given, each intervening value between the upper and lower limit of that range is specifically disclosed to the smallest unit of the lower limit, unless the context clearly indicates otherwise. Any narrower ranges between any stated or unstated intervening value in a stated range, as well as any other stated or intervening value in that stated range, are also encompassed. The upper and lower limits of these smaller ranges may be individually included or excluded from the range, and each range in which either, neither or both limits are included in the smaller ranges is also encompassed within the scope of this technology, subject to any specifically excluded limits in the stated range. Where a stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included.

[0058]

[0065] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, a reference to "a precursor" includes a plurality of such precursors, a reference to "the layer" includes a reference to one or more layers and equivalents thereof known to those skilled in the art, and so forth.

[0059]

[0066] Additionally, the terms "comprise(s)", "comprising", "contain(s)", "containing", "include(s)", and "including", when used in this specification and claims, are intended to specify the presence of stated features, integers, components, or steps, but do not exclude the presence or addition of one or more other features, integers, components, steps, operations, or groups.

Claims

1. flowing an oxygen-containing precursor into a processing region of a semiconductor processing chamber; contacting a substrate contained within the processing region with the oxygen-containing precursor, the substrate including exposed areas of ruthenium, the contacting producing ruthenium tetroxide; evaporating the ruthenium tetroxide from the surface of the exposed area of ​​ruthenium, leaving behind an amount of oxidized ruthenium; contacting the oxidized ruthenium with a hydrogen-containing precursor; removing said oxidized ruthenium; An etching method comprising:

2. forming a plasma from said oxygen-containing precursor; 2. The method of claim 1 further comprising flowing plasma effluents into the processing region.

3. 10. The etching method of claim 1, wherein a temperature in the processing region is maintained at or above about 100 degrees Celsius.

4. 4. The etching method of claim 3, wherein the temperature in the processing region is maintained at or below about 150°C.

5. The etching method of claim 1 , wherein the hydrogen-containing precursor comprises diatomic hydrogen.

6. contacting the substrate with the hydrogen-containing precursor prior to flowing the oxygen-containing precursor, the hydrogen-containing precursor exposing the regions of ruthenium; The etching method of claim 1 further comprising additional steps.

7. 10. The etching method of claim 1, wherein the processing region is maintained plasma-free throughout the etching method.

8. 10. The etching method of claim 1, wherein additional ruthenium is exposed by removing the oxidized ruthenium and the method is repeated for additional cycles.

9. 2. The etching method of claim 1, wherein the ruthenium is removed selectively to exposed areas of silicon oxide, titanium oxide, or tungsten oxide.

10. 10. The method of claim 1, wherein a pressure in the semiconductor processing chamber is maintained at or above about 1 Torr.

11. flowing an oxygen-containing precursor into a processing region of a semiconductor processing chamber; contacting a substrate contained within the processing region with the oxygen-containing precursor, the substrate including exposed areas of ruthenium, the contacting producing ruthenium tetroxide; performing a particle treatment with an inert precursor in the processing region of the semiconductor processing chamber; contacting the ruthenium tetroxide with the inert precursor; removing said ruthenium tetroxide; An etching method comprising:

12. forming a plasma from the oxygen-containing precursor in the processing region or a remote plasma region of the semiconductor processing chamber; The etching method of claim 11 further comprising:

13. 12. The etching method of claim 11, wherein the pressure in the semiconductor processing chamber is maintained at or below about 25°C.

14. 12. The etching method of claim 11, wherein a plasma is formed from the inert precursor, and a plasma power used to form the plasma from the inert precursor is maintained at about 500 W or less.

15. 12. The etching method of claim 11, wherein additional ruthenium is exposed by removing the ruthenium tetroxide, and the method is repeated for additional cycles.

16. contacting the substrate with a hydrogen-containing precursor prior to flowing the oxygen-containing precursor, the hydrogen-containing precursor exposing the regions of ruthenium; The etching method of claim 11 further comprising additional steps.

17. contacting a substrate disposed within a processing region of a semiconductor processing chamber with a hydrogen-containing precursor, said contacting exposing ruthenium metal on said substrate; flowing an oxygen-containing precursor into the processing region of the semiconductor processing chamber; contacting the ruthenium metal exposed on the substrate with the oxygen-containing precursor, said contacting producing ruthenium tetroxide; evaporating the ruthenium tetroxide from the surface of the ruthenium metal; An etching method comprising:

18. 20. The etching method of claim 17, wherein the temperature in the processing region is maintained at or below about 150°C.

19. forming a plasma from the oxygen-containing precursor in the semiconductor processing chamber; The etching method of claim 17 further comprising:

20. Repeating the method for at least one additional cycle. The etching method of claim 17 further comprising:

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