Selective removal of ruthenium-containing materials

Abstract

An exemplary etching method can include flowing an oxygen-containing precursor into a processing region of a semiconductor processing chamber. The method can include contacting a substrate contained in the processing region with the oxygen-containing precursor. The substrate can include an exposed ruthenium region, and the contacting can produce ruthenium tetroxide. The method can include vaporizing the ruthenium tetroxide from a surface of the exposed ruthenium region. An amount of oxidized ruthenium can be retained. The method can include contacting the oxidized ruthenium with a hydrogen-containing precursor. The method can include removing the oxidized ruthenium.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. non-provisional application No. 17 / 240,149, filed April 26, 2021, entitled “SELECTIVE REMOVAL OF RUTHENIUM-CONTAINING MATERIALS,” the contents of which are incorporated herein by reference in their entirety for all purposes. Technical Field

[0003] This technology relates to semiconductor processes and equipment. More specifically, this technology relates to the selective etching of ruthenium-containing structures. Background Technology

[0004] Integrated circuits can be fabricated by creating intricately patterned material layers on a substrate surface. Creating patterned material on the substrate requires controlled methods for removing exposed material. Chemical etching is used for various purposes, including transferring patterns from photoresist to underlying layers, thinning layers, or thinning the lateral dimensions of features already present on a surface. It is generally desirable to have etching processes that etch one material faster than another, such as pattern transfer processes. Such etching processes are said to be selective for the first material. Due to the diversity of materials, circuits, and processes, etching processes with selectivity for a wide range of materials have been developed.

[0005] Depending on the materials used in the process, etching processes can be referred to as wet etching or dry etching. For example, wet etching can preferentially remove certain oxide dielectrics relative to other dielectrics and materials. However, wet processes may struggle to penetrate some constrained trenches and can sometimes deform the remaining material. Dry etching, generated in localized plasma within the substrate processing area, can penetrate more constrained trenches and exhibit less deformation of the fine remaining structure. However, localized plasma can generate arcs during discharge, damaging the substrate.

[0006] Therefore, 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 this technology. Summary of the Invention

[0007] An exemplary etching method may include introducing an oxygen-containing precursor into a processing region of a semiconductor processing chamber. The method may include contacting a substrate housed in the processing region with the oxygen-containing precursor. The substrate may include exposed ruthenium regions, and the contact may generate ruthenium tetroxide. The method may include vaporizing the ruthenium tetroxide from the surface of the exposed ruthenium regions. An amount of oxidized ruthenium may remain. The method may include contacting the oxidized ruthenium with a hydrogen-containing precursor. The method may include removing the oxidized ruthenium.

[0008] In some embodiments, the method may include: forming a plasma of the oxygen-containing precursor, wherein the plasma effluent flows into the processing region. The temperature within the processing region may be maintained at a level greater than or approximately 100°C. The temperature within the processing region may be maintained at a level less than or approximately 150°C. The hydrogen-containing precursor may be diatomic hydrogen or include diatomic hydrogen. The method may include: contacting the substrate with the hydrogen-containing precursor before allowing the oxygen-containing precursor to flow. The hydrogen-containing precursor may expose ruthenium regions. The processing region may remain plasma-free throughout the etching process. Removing oxidized ruthenium may expose additional ruthenium. The method may be repeated with additional cycles. The ruthenium may be selectively removed relative to exposed areas of silicon oxide, titanium oxide, or tungsten oxide. The pressure within the semiconductor processing chamber may be maintained at a level greater than or approximately 1 Torr.

[0009] Some embodiments of this technology may cover etching methods. The method may include: introducing an oxygen-containing precursor into a processing region of a semiconductor processing chamber. The method may include: contacting a substrate housed in the processing region with the oxygen-containing precursor. The substrate may include an exposed area of ​​ruthenium. The contact may generate ruthenium tetroxide. The method may include: performing particle treatment with an inert precursor within 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.

[0010] In some embodiments, the method may include: forming a plasma of the oxygen-containing precursor in the processing region or remote plasma region of the semiconductor processing chamber. The pressure within the semiconductor processing chamber may be maintained at less than or about 25°C. The plasma may be formed from an inert precursor. The plasma power used to form the inert precursor may be maintained at less than or about 500W. Removing ruthenium tetroxide may expose additional ruthenium. The method may be repeated with additional cycles. The method may include: contacting the substrate with a hydrogen-containing precursor before allowing the oxygen-containing precursor to flow. The hydrogen-containing precursor may expose ruthenium regions.

[0011] Some embodiments of this technology may cover etching methods. The method may include: contacting a substrate disposed within a processing region of a semiconductor processing chamber with a hydrogen-containing precursor. Contact may expose ruthenium metal on the substrate. The method may include: flowing an oxygen-containing precursor into the processing region of the semiconductor processing chamber. The method may include: contacting the ruthenium metal exposed on the substrate with the oxygen-containing precursor. Contact may generate ruthenium tetroxide. The method may include: vaporizing the ruthenium tetroxide from the surface of the ruthenium metal. In some embodiments, the temperature within the processing region may be maintained at less than or about 150°C. The method may include: forming a plasma of the oxygen-containing precursor within the semiconductor processing chamber. The method may include: repeating the method at least one additional cycle.

[0012] Compared to conventional systems and techniques, this technology offers numerous advantages. For example, these processes allow for precisely controlled dry etching, which removes discreet layers of ruthenium-containing material. Furthermore, the process selectively removes the ruthenium-containing film relative to other exposed material on the substrate. These and other embodiments, along with their many advantages and features, are described in more detail below with reference to the accompanying drawings. Attached Figure Description

[0013] The nature and advantages of the disclosed technology can be further understood by referring to the remainder of the specification and drawings.

[0014] Figure 1 A top plan view of one embodiment of an exemplary processing system according to some embodiments of the present technology is shown.

[0015] Figure 2A A schematic cross-sectional view of an exemplary processing chamber according to some embodiments of the present technology is shown.

[0016] Figure 2B Some embodiments according to the present technology are shown. Figure 2A A detailed view of a portion of the processing chamber shown.

[0017] Figure 3 A bottom plan view of an exemplary nozzle according to some embodiments of the present technology is shown.

[0018] Figure 4 Exemplary operations in methods according to some embodiments of the present technology are shown.

[0019] Figures 5A to 5C A schematic cross-sectional view of the material etched according to some embodiments of the present technology is shown.

[0020] Figure 6 Exemplary operations in methods according to some embodiments of the present technology are shown.

[0021] Figures 7A to 7C A schematic cross-sectional view of the material etched according to some embodiments of the present technology is shown.

[0022] Several of the accompanying drawings are included as illustrative. It should be understood that the drawings are for illustrative purposes only and should not be considered to be drawn to scale unless specifically stated otherwise. Furthermore, the drawings are provided to aid understanding and may not include all aspects or information compared to the actual representation, and may include additional or exaggerated material for illustrative purposes.

[0023] In the accompanying drawings, similar parts and / or features may have the same reference numerals. Furthermore, various parts of the same type may be distinguished by adding a letter after the reference numeral to differentiate between similar parts. If only a first reference numeral is used in the specification, the description applies to any similar parts having the same first reference numeral, regardless of the letter. Detailed Implementation

[0024] As the size of electronic components continues to shrink, the transition to future technology nodes has revealed the challenges of scaling semiconductor materials. For example, copper has been used as an interconnect or wiring material due to the relatively low resistivity of metals. However, as critical dimensions continue to decrease, copper has shown an increasing resistivity. For relatively large linewidths, copper can maintain a low resistivity to preserve device performance. However, as wiring shrinks to below 50 nm, the resistivity of copper can increase dramatically due to surface scattering. Scattering is likely related to electrons moving with the current. When electrons reach the sidewalls, they may lose momentum in some sense, and the effective resistance begins to increase. At lower linewidths, the effective mean free path of electrons decreases and scattering increases; for copper, the resistivity can be more than five times higher than that of the standard bulk.

[0025] Because copper is characterized by its low resistivity, it may still outperform other materials at larger linewidths. However, as the linewidth decreases, the sharp increase in copper's resistivity can cause other materials to begin to outperform it. For example, ruthenium is characterized by a less significant increase in resistivity during component scaling, which may become less than that of copper at certain linewidths. However, ruthenium is often processed using chlorine-based etching processes, which can lead to increased surface roughness. At material interfaces, this increased roughness can adversely affect resistivity by further increasing scattering.

[0026] This technology overcomes these problems by performing an etching process that removes ruthenium from a hidden layer and can selectively etch the surrounding material, including several oxide materials. By developing or releasing the oxidized material to remove ruthenium, this technology provides an etching process that delivers a smoother interface surface compared to many conventional chemical etching methods. While the remainder of the disclosure will routinely identify specific materials and semiconductor structures utilizing the disclosed techniques, it will be readily understood that the systems, methods, and materials are equally applicable to many other structures that may benefit from aspects of this technology. Therefore, the technology should not be considered limited to use with any particular process or individual material. Furthermore, while exemplary chambers have been described to provide a basis for this technology, it should be understood that this technology can indeed be implemented in any semiconductor processing chamber that allows the described operations.

[0027] Figure 1 A top plan view of one embodiment of a processing system 100 comprising deposition, etching, baking, and curing chambers according to an embodiment is shown. In the figure, a pair of front-opening standard chambers 102 supply substrates of various sizes received by a robotic arm 104 and placed in a low-pressure receiving region 106 before being placed into one of the substrate processing chambers 108a-f located in tandem sections 109a-c. A second robotic arm 110 is used to transport the substrate from the receiving region 106 to and from the substrate processing chamber 108a-f. Each substrate processing chamber 108a-f can be configured to perform several substrate processing operations, including, in addition to cyclic layer deposition, atomic layer deposition, chemical vapor deposition, physical vapor deposition, etching, pre-cleaning, degassing, orientation, and other substrate processes, the dry etching process described herein.

[0028] The substrate processing chambers 108a-f may include one or more system components for depositing, annealing, curing, and / or etching dielectric films on a substrate wafer. In one configuration, two pairs of processing chambers (e.g., 108c-d and 108e-f) may be used to deposit dielectric material on the 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 dielectric films on the substrate. Any one or more of the processes described may be performed in one or more chambers separate from the manufacturing systems shown in the different embodiments. It should be understood that system 100 may be considered for additional configurations for the deposition, etching, annealing, and curing chambers for dielectric films.

[0029] Figure 2AA cross-sectional view of an exemplary processing chamber system 200 is shown, wherein the processing chamber has partitioned plasma generation regions. During film etching (e.g., titanium nitride, tantalum nitride, tungsten, silicon, polysilicon, silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, etc.), process gases flow into a 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 the gas inlet assembly 205. The inlet assembly 205 may include two or more distinct gas supply channels, wherein a second channel may bypass the remote plasma system 201 (if included).

[0030] The diagram shows a cooling plate 203, a panel 217, an ion suppressor 223, a nozzle 225, and a base 265 or substrate support (on which a substrate 255 is disposed), and each of these may be included according to embodiments. The base 265 may have heat exchange channels through which heat exchange fluid flows to control the temperature of the substrate. The heat exchange fluid may be operated during processing operations to heat and / or cool the substrate or wafer. An embedded resistance heater element may also be used to resistively heat the wafer support pad of the base 265 (which may include aluminum, ceramic, or a combination thereof) to achieve relatively high temperatures, such as from up to or about 100°C to about 1100°C or above.

[0031] Panel 217 may be pyramidal, conical, or other similar structures with a narrow top portion extending to a wide bottom portion. As shown, panel 217 may additionally be flat and include multiple through-channels for distributing process gases. Depending on the use of the remote plasma system 201, plasma generating gases and / or plasma excitation materials may pass through multiple holes in panel 217 (e.g., Figure 2B (as shown), to be used for more uniform delivery into the first plasma region 215.

[0032] Exemplary configurations may include directing the gas inlet assembly 205 toward a gas supply region 258 separated from the first plasma region 215 by the panel 217, such that gas / material flows through an opening in the panel 217 into the first plasma region 215. Selectable structural and operational features may prevent significant backflow of plasma from the first plasma region 215 into the supply region 258, the gas inlet assembly 205, and the fluid supply system 210. An insulating ring 220 is shown positioned between the conductive top portion of the panel 217 or chamber and these features, and the nozzle 225. The insulating ring 220 allows an AC potential to be applied to the panel 217 relative to the nozzle 225 and / or the ion suppressor 223. The insulating ring 220 may be positioned between the panel 217 and the nozzle 225 and / or the ion suppressor 223 to enable the formation of capacitively coupled plasma in the first plasma region. A baffle may also be located in the first plasma region 215, or otherwise coupled to the gas inlet assembly 205, to influence fluid flow into the region through the gas inlet assembly 205.

[0033] Ion suppressor 223 may include a plate or other geometry defining a plurality of holes throughout the structure. These holes are configured to suppress the migration of ionicly charged material from the first plasma region 215, while allowing uncharged neutral or free radical material to pass through the ion suppressor 223 into the activation gas delivery region between the suppressor and the nozzle. In embodiments, ion suppressor 223 may include a perforated plate with various hole configurations. These uncharged materials may include highly reactive materials, which are delivered through the holes along with a less reactive carrier gas. As described above, ionic material migration through the holes can be reduced and, in some cases, completely suppressed. Controlling the amount of ionic material passing through ion suppressor 223 can advantageously increase control over the gas mixture in contact with the underlying wafer substrate, which in turn can increase control over the deposition and / or etching characteristics of the gas mixture. For example, adjusting the ion concentration of the gas mixture can significantly alter its etching selectivity, such as the SiNx:SiOx etch ratio, Si:SiOx etch ratio, etc. In alternative embodiments where deposition is performed, it can also alter the balance of conformal-to-flowable deposition for dielectric materials.

[0034] Multiple orifices in ion suppressor 223 can be configured to control the passage of activating gas (i.e., ions, free radicals, and / or neutral substances) through ion suppressor 223. For example, the aspect ratio, or diameter-to-length ratio, and / or geometry of the orifices can be controlled to reduce the flow of ionic charged substances in the activating gas through ion suppressor 223. The orifices in ion suppressor 223 may include a tapered portion facing plasma excitation region 215 and a cylindrical portion facing nozzle 225. The shape and size of the cylindrical portion can be adjusted to control the flow of ionic substances to nozzle 225. An adjustable electrical bias can also be applied to ion suppressor 223 as an additional means of controlling the flow of ionic substances through the suppressor.

[0035] Ion suppressor 223 can be used to reduce or eliminate the amount of ionicly charged material from the plasma generation region to the substrate. Uncharged neutral material and free radical material can still pass through the openings in the ion suppressor to react with the substrate. It should be noted that, in embodiments, ionicly charged material may not be completely eliminated in the reaction region surrounding the substrate. In some cases, ionic material is intended to reach the substrate to perform etching and / or deposition processes. In these cases, ion suppressor can help control the concentration of ionic material in the reaction region to a level conducive to the process.

[0036] The combination of nozzle 225 and ion suppressor 223 allows the plasma present in the first plasma region 215 to avoid directly exciting the gas in the substrate processing region 233, while still allowing the excited material to travel from the chamber plasma region 215 to the substrate processing region 233. In this way, the chamber can be configured to prevent plasma from contacting the etched substrate 255. This can advantageously protect various complex structures and films patterned on the substrate that could be damaged, dislocated, or otherwise warped if they came into direct contact with the generated plasma. Additionally, the etching rate of oxide materials may increase when plasma is allowed to contact the substrate or approach the substrate plane. Therefore, if the exposed areas of the material are oxides, this material can be further protected by keeping the substrate away from the plasma.

[0037] The processing system may further include a power supply 240 electrically coupled to the processing chamber to provide power to the panel 217, ion suppressor 223, nozzle 225, and / or base 265 to generate plasma in the first plasma region 215 or processing region 233. The power supply can be configured to deliver an adjustable amount of power to the chamber according to the process being performed. Such a configuration allows for the use of tunable plasma in the process being performed. Unlike remote plasma units (which typically have an on / off function), tunable plasma can be configured to deliver a specific amount of power to plasma region 215. This, in turn, allows for the development of specific plasma characteristics, enabling precursors to dissociate in a specific manner to enhance the etch distribution produced by these precursors.

[0038] Plasma can be ignited in the chamber plasma region 215 above nozzle 225 or in the substrate processing region 233 below nozzle 225. Plasma can be present in the chamber plasma region 215 to generate radical precursors from an inflow of, for example, a fluorine-containing precursor or other precursors. An AC voltage, typically in the radio frequency (“RF”) range, can be applied between the conductive top portion of the processing chamber (such as panel 217) and nozzle 225 and / or ion suppressor 223 to ignite the plasma in the chamber plasma region 215 during deposition. The RF power supply can generate a high RF frequency of 13.56 MHz, but other frequencies can also be generated alone or in combination with the 13.56 MHz frequency.

[0039] Figure 2B A detailed view 253 shows characteristics affecting the distribution of the processed gas through panel 217. (See also...) Figure 2A and Figure 2B As shown, panel 217, cooling plate 203, and gas inlet assembly 205 intersect to define gas supply region 258, into which process gas can be supplied from gas inlet 205. Gas can fill gas supply region 258 and flow through orifice 259 in panel 217 to first plasma region 215. Orifice 259 can be configured to guide flow in a substantially unidirectional manner, allowing process gas to flow into processing region 233, but partially or completely preventing backflow into gas supply region 258 after passing through panel 217.

[0040] The gas distribution assembly (such as nozzle 225) used in the treatment chamber section 200 may be referred to as a dual-channel nozzle, and Figure 3 The embodiments described herein are further detailed. A dual-channel nozzle can provide an etching process that allows the etchant to be separated outside the processing area 233 to provide limited interaction with the chamber components and with each other before being delivered to the processing area.

[0041] The nozzle 225 may include an upper plate 214 and a lower plate 216. The plates may be coupled to each other to define a volume 218 between them. The coupling of the plates provides a first fluid passage 219 through the upper and lower plates, and a second fluid passage 221 through the lower plate 216. The formed passage may be configured to provide a fluid pathway from the volume 218 through the second fluid passage 221 to the lower plate 216, and the first fluid passage 219 may be fluidly isolated from the volume 218 between the plates and the second fluid passage 221. The volume 218 may fluidly enter and exit through the side of the nozzle 225.

[0042] Figure 3 This is a bottom view of a nozzle 325 used with a processing chamber according to an embodiment. The nozzle 325 may correspond to... Figure 2A The nozzle 225 is shown. The through-hole 365 (showing a view of the first fluid channel 219) can have multiple shapes and configurations to control and influence the flow of precursors through the nozzle 225. The orifices 375 (showing a view of the second fluid channel 221) can be substantially uniformly distributed on the surface of the nozzle, or even substantially uniformly distributed within the through-hole 365, and can contribute to providing a more uniform precursor mixing than other configurations when the precursors leave the nozzle.

[0043] The chambers discussed earlier can be used to perform exemplary methods (including etching methods), although any number of chambers can be configured to perform one or more aspects used in embodiments of this technology. (Turn to...) Figure 4 This illustrates exemplary operations in method 400 according to an embodiment of the present technology. Method 400 may include one or more operations prior to the start of the method, including front-end processing, deposition, etching, polishing, cleaning, or any other operations that may be performed prior to said operations. The method may include several optional operations, which may or may not be specifically associated with some embodiments of the method according to the present technology. For example, many operations are described to provide a broader range of processes performed, but these are not critical to the present technology or may be performed by alternative methods, as will be discussed further below. Method 400 may describe Figures 5A to 5C The operations illustrated in the figures will be described in conjunction with the operations of method 400. It should be understood that the figures show only partial schematic diagrams, and the substrate may include any number of additional materials and features having the various properties and aspects shown in the figures.

[0044] Method 400 may or may not involve optional operations such as developing the semiconductor structure to a particular manufacturing operation. It should be understood that method 400 can be implemented on any number of semiconductor structures or substrates 505, such as... Figure 5AAs shown, it includes an exemplary structure on which ruthenium-containing material removal operations can be performed. The exemplary semiconductor structure 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 and an interlayer dielectric material that can form trenches, vias, or isolation structures. The material exposed at any time during the etching process may be or may include metallic materials, one or more dielectric materials, contact materials, transistor materials, or any other material that can be used in semiconductor processes.

[0045] For example, although it is shown as a generic layer, Figure 5A A layer of ruthenium 510 covering substrate 505 or some other semiconductor material may be shown. Although the remainder of the disclosure will refer to ruthenium, it should be understood that ruthenium material 510 may also be ruthenium oxide, whether a native oxide or an oxidized surface. Substrate 505 may show a dielectric material overlying one or more other structures on the substrate, and it should be understood that any number of materials may be formed beneath the illustrated structures. In some embodiments, the dielectric material may be or include silicon oxide, or any other oxide or nitride that may be patterned therethrough. It should be understood that the structures mentioned are not intended to be limiting, and any of a variety of other semiconductor structures including ruthenium-containing materials or other metallic materials are similarly covered. Other exemplary structures may include two-dimensional and three-dimensional structures common in semiconductor manufacturing, in which the ruthenium-containing material (such as ruthenium metal or ruthenium oxide) is removed relative to one or more other materials, as this technology may selectively remove the ruthenium-containing material relative to other exposed materials (such as silicon oxide, titanium oxide, tungsten oxide, and any other materials discussed elsewhere and various other exposed materials). Furthermore, while high-aspect-ratio structures can benefit from this technology, the technology is equally applicable to lower aspect ratio and any other structure.

[0046] In embodiments of this technology, method 400 may be performed to remove exposed ruthenium-containing material. The method may include specific operations for removing the ruthenium metal. Although the remainder of this disclosure will routinely discuss ruthenium and ruthenium oxide, it should be understood that other metals may be similarly processed by some embodiments of this technology. In some embodiments, the method may include a multi-operation etching process that controls the etching of ruthenium relative to other exposed materials (such as dielectric materials, e.g., silicon oxide) and any underlying contact materials (such as conductive materials used in structures that may be coupled to one or more component structures).

[0047] As previously mentioned, a certain amount of oxidation may be present on the surface of ruthenium 510, and this oxidation can be removed before the etching process. Whether the oxidation is a natural oxide or residual oxidation from previous treatments (including previous cycles of method 400), removing the oxidation can promote the formation of specific oxidized substances, which may allow for increased ruthenium removal in some embodiments of this technology. Therefore, in some embodiments, method 400 may include contacting the substrate with a hydrogen-containing precursor at optional operation 405. The hydrogen reduces water vapor generated by oxidation, which can be purged from the chamber and expose the ruthenium surface to the substrate.

[0048] Method 400 may include: in operation 410, flowing an oxygen-containing precursor into a semiconductor processing chamber housing the substrate. In some embodiments, the oxygen-containing precursor may flow directly to contact the substrate, but in some embodiments, plasma may be formed by the oxygen-containing precursor. The plasma may be formed remotely or within a processing region of the semiconductor processing chamber in which the substrate is housed. The oxygen-containing precursor may flow through a remote plasma region of the processing chamber (such as region 215 described above), and plasma may be formed by the oxygen-containing precursor to produce a plasma effluent. Although substrate-level plasma may be generated, in some embodiments, the plasma may be a remote plasma, which can protect exposed substrate material from ion bombardment that may occur due to substrate-level plasma.

[0049] Regardless of whether plasma enhancement is used, in operation 410, an oxygen-containing precursor or plasma effluent of an oxygen-containing precursor can be delivered to a substrate processing region, where the effluent can contact a semiconductor substrate including exposed ruthenium-containing material, such as the exposed ruthenium area in operation 415. This contact can (e.g., by converting the exposed ruthenium on the substrate) generate an oxidized material, such as an oxide surface on ruthenium or ruthenium oxide material. In some embodiments, when plasma is formed, after oxidation, the plasma can be extinguished, and the chamber can be cleaned. Figure 5A As shown, oxygen material or oxygen plasma effluent 515 can flow to contact exposed ruthenium material 510, which can convert the exposed surface of ruthenium 510 into oxidized ruthenium material 520, such as... Figure 5B As shown.

[0050] This technology allows control over one or more conditions during oxidation to produce a specific oxide of ruthenium. For example, in some embodiments of this technology, a contact operation can be performed to produce a quantity of ruthenium tetroxide along a substrate surface. By producing ruthenium tetroxide (such as in place of ruthenium dioxide), this technology allows for selective removal of ruthenium relative to several other exposed materials on the substrate. For example, unlike ruthenium dioxide, which has a dense structure that may limit removal during processing, ruthenium tetroxide is characterized by a relatively low boiling point. Therefore, when ruthenium oxidation is performed to produce ruthenium tetroxide, the resulting material can be vaporized from the surface of the substrate. Thus, in some embodiments, method 400 may include, in operation 420, vaporizing at least a portion of the ruthenium tetroxide from the substrate to remove volatile material from the underlying ruthenium or substrate material. Figure 5B As shown, due to the processing conditions, ruthenium tetroxide 525 can vaporize from the surface of the structure.

[0051] For example, method 400 can be performed at a temperature sufficient to vaporize the generated ruthenium tetroxide from the surface. Therefore, in some embodiments, method 400 can be performed at a temperature greater than or about 60°C, and can be performed at temperatures greater than or about 80°C, greater than or about 100°C, greater than or about 110°C, greater than or about 120°C, greater than or about 130°C, greater than or about 140°C, greater than or about 150°C, or higher. However, as the temperature increases, the oxidation process can transition to producing ruthenium dioxide of a higher density, which may not vaporize due to its significantly higher boiling point. Therefore, in some embodiments, the method can be performed at a temperature less than or about 170°C, and can be performed at temperatures less than or about 160°C, less than or about 150°C, or lower. By maintaining the temperature within a window sufficient to allow ruthenium tetroxide vaporization, this technique allows for the removal of ruthenium from the substrate while maintaining a sufficiently low temperature to limit or prevent the generation of ruthenium dioxide.

[0052] Advantageously, since many other materials may not vaporize at the operating temperatures of method 400 (e.g., between about 100°C and about 150°C), the method can selectively remove ruthenium while substantially or completely maintaining other exposed materials, including silicon oxide, titanium oxide, tungsten oxide, or other materials. Exposed metals can also be maintained by method 400, which may oxidize only the surface of the material without causing etching. As described above, in some embodiments, method 400 may not include plasma-enhanced oxygen-containing precursors and can be performed while maintaining a plasma-free environment. In some embodiments, this can further limit damage to or removal of other exposed materials.

[0053] Following the oxidation operation, the delivery of oxygen material can be stopped. Due to the oxidation of ruthenium, residual oxidized ruthenium may remain after the vaporization of ruthenium tetroxide, and it may not be a volatile substance. This may limit the continuous etching process or slow it down. Therefore, in some embodiments, the method may include contacting the residual oxidized ruthenium with a hydrogen-containing precursor before continuing the delivery of the oxygen-containing precursor. This can generate volatile water vapor, which can be purified from the processing chamber and can reduce the surface to ruthenium. Figure 5C As shown, hydrogen-containing material 520 can flow to residual oxidized ruthenium material 527, which can reduce the surface to ruthenium or remove the oxidized material, such as... Figure 5A As shown, although the amount is small, or it can accomplish the removal operation. The contact may be similar to or equivalent to the hydrogen pretreatment as described above in optional operation 405. Therefore, in some embodiments, the method may begin and / or end together with hydrogen treatment. The process may be repeated in one or more cycles to remove the additional ruthenium layer from the substrate.

[0054] The precursor during each two-step operation may include an oxygen-containing precursor, which 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. Hydrogen-containing materials may be or include diatomic hydrogen or any other hydrogen-containing material, including, for example, hydrogen-containing materials comprising oxygen or nitrogen. The precursor may also flow with any number of additional precursors or carrier gases (including nitrogen, argon, helium, or any number of additional materials), although in some embodiments, the precursor may be limited to controlling side reactions or other aspects that may affect selectivity.

[0055] As previously stated, processing conditions can influence and facilitate etching according to this technology. In addition to temperature, the pressure within the chamber can also affect the operations performed and the temperature at which ruthenium tetroxide can develop from the ruthenium surface. Therefore, in some embodiments, the pressure can be maintained at a level greater than or about 1 Torr, and can be maintained at pressures 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, or higher. The pressure can also be maintained within these ranges, within a smaller range encompassed by these ranges, or between any of these ranges.

[0056] This technology can also provide additional mechanisms for removing ruthenium from semiconductor substrates. (Go to...) Figure 6 This illustrates a method 600 for etching a ruthenium-containing material according to an embodiment of the present technology. Method 600 can be described as follows: Figures 7A to 7CThe operations illustrated herein will be described in conjunction with the operations of method 600. It should be understood that the illustrations show only partial schematics, and the substrate may include any number of additional materials and features having the various properties and aspects shown in the illustrations.

[0057] Method 600 may or may not involve optional operations such as developing the semiconductor structure to a specific manufacturing operation. Additionally, method 600 may include any or all of the operations discussed above with respect to method 400, and may include any of the process conditions discussed above. It should be understood that method 600 can be implemented on any number of semiconductor structures or substrates 705, such as... Figure 7A As shown, and as discussed above with respect to method 400. This may cover any substrate previously mentioned or used for semiconductor processing, wherein the substrate includes a layer of ruthenium-containing material 710, such as ruthenium metal, exposed on the substrate.

[0058] Similar to method 400, ruthenium may have residual oxidized material, natural oxides, or other aspects that can be removed in optional operation 605, as discussed above regarding operation 405. In operation 610, an oxygen-containing precursor may flow into the processing chamber. As discussed above regarding operation 410, the oxygen-containing precursor may or may not be plasma-enhanced, and the oxygen-containing precursor may be any of the materials mentioned above. The oxygen-containing precursor or its plasma effluent may contact the substrate at operation 615 and may contact the exposed ruthenium. Figure 7A As shown, oxygen-containing material 715 can contact ruthenium 710. For example... Figure 7B As shown, oxygen-containing materials can be delivered to generate ruthenium tetroxide 720 on the ruthenium surface.

[0059] Method 400 can provide volatile ruthenium tetroxide that can be evolved from ruthenium materials, while method 600 can be performed to remove a controlled, concealed ruthenium layer by maintaining ruthenium tetroxide on the substrate surface, such as... Figure 7B As shown. For example, method 600 can be performed under any of the processing conditions discussed above, such as with respect to method 400. Furthermore, in some embodiments, method 600 can be performed at temperatures below the vaporization temperature of ruthenium tetroxide. For example, method 600 can be performed at temperatures less than or about 50°C, and can be performed at temperatures less than or about 40°C, less than or about 30°C, less than or about 25°C, less than or about 20°C, less than or about 15°C, less than or about 10°C, less than or about 5°C, less than or about 0°C, or lower. This allows a ruthenium tetroxide layer to form and remain across the surface of ruthenium.

[0060] In operation 620, the method may include performing particle treatment with an inert precursor. The plasma may be formed in a remote portion of a semiconductor processing chamber or within a processing region of the semiconductor processing chamber. While any number of reactive materials may be used, in some embodiments, an inert precursor (such as argon, helium, or some other material) may be used and delivered to a substrate. For example, a bias voltage may be used to guide the plasma effluent to a substrate surface, which may operate as a cathode within the chamber. The plasma effluent may contact ruthenium tetroxide, which may provide sufficient energy to release the ruthenium tetroxide from the ruthenium surface, and the material may be removed in operation 625. Figure 7C As shown, the inert effluent 725 can contact the substrate surface and cause ruthenium tetroxide 730 to be released from the surface and purified from the processing chamber. This removes the ruthenium layer from the substrate and exposes additional ruthenium.

[0061] By maintaining a layer of ruthenium tetroxide on the surface, additional oxidation can be controlled, and this allows for layered etching processes. The method can be repeated any number of times to remove the desired amount of ruthenium. As mentioned above, after the release operation, additional oxidized material, which may not be ruthenium tetroxide, may remain on the substrate surface. Additional operations, including contacting the residual material with hydrogen or hydrogen effluent, can be performed as described above to reduce the surface to ruthenium. Therefore, as described above, and for any of the methods according to this technology, during each cycle, the cycle may or may not include hydrogen treatment, or some cycles may include hydrogen treatment while other cycles may directly involve additional oxygen contact.

[0062] When plasma effluent is used during one or both of the operations (such as when oxygen-containing precursors and / or inert plasmas are used), the plasma power can be maintained at less than or about 500 W. By maintaining a lower plasma power, sputtering beneath ruthenium can be controlled, and interactions can be limited to surface physical reactions, which better limits the extent of removal through the ruthenium-containing material. Therefore, in some embodiments of any of the methods for forming plasma discussed, the plasma power can be maintained at less than or about 450 W, less than or about 400 W, less than or about 350 W, less than or about 300 W, less than or about 250 W, less than or about 200 W, less than or about 150 W, less than or about 100 W, or lower. By performing an etching operation according to embodiments of the present technology, a substantially self-limiting removal operation can be performed to precisely remove ruthenium, and this substantially self-limiting operation can be performed at temperatures that limit the removal of additional exposed material across the substrate.

[0063] In the foregoing description, numerous details have been set forth for illustrative purposes in order to provide an understanding of various embodiments of the present technology. However, it will be apparent to those skilled in the art that certain embodiments may be practiced without some of these details or with others.

[0064] Several embodiments have been disclosed, and those skilled in the art will recognize that various modifications, alternative configurations, and equivalents can be used without departing from the spirit of the embodiments. Furthermore, to avoid unnecessarily obscuring the present technology, many well-known processes and elements have not been described. Therefore, the above description should not be considered as limiting the scope of the present technology. Additionally, methods or processes may be described as sequential or step-by-step, but it should be understood that the operations may be performed simultaneously or in a different order than those listed.

[0065] When providing a numerical range, it should be understood that, unless explicitly stated otherwise in the context, all intermediate values ​​(down to the smallest unit fraction of the lower limit) between the upper and lower limits of the range are also specifically disclosed. Any smaller range between any specified numerical values, or any unspecified intermediate value within a specified range, as well as any other specified numerical value or intermediate value within the specified range, are covered. The upper and lower limits of those smaller ranges may be independently included or excluded from the range, and each range (whether one or both of the upper and lower limits are included in the smaller range) is also covered within this technique and subject to any specific exclusions within the specified range. When a specified range includes one or both of the specified limit values, it also includes ranges that exclude any or both of those included limit values.

[0066] Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” as used in this specification and the appended claims include plural references. Thus, for example, the reference to “a precursor” includes a plurality of such precursors, while the reference to “the layer” includes references to one or more layers and equivalents known to those skilled in the art, etc.

[0067] Furthermore, the terms “comprise(s)”, “comprising”, “contain(s)”, “containing”, “include(s)”, and “including”, when used in this specification and the appended claims, are intended to specify the presence of the indicated feature, integer, component, or operation, but the terms do not exclude the presence or addition of one or more other features, integers, components, operations, actions, or groups.

Claims

1. An etching method, comprising: This allows oxygen-containing precursors to flow into the processing area of ​​the semiconductor processing chamber; The substrate contained in the processing area is brought into contact with the oxygen-containing precursor, wherein the substrate includes an exposed ruthenium region, and wherein the contact produces ruthenium tetroxide. The ruthenium tetroxide is vaporized from the surface of the exposed ruthenium region, wherein a certain amount of oxidized ruthenium is retained; The oxidized ruthenium is brought into contact with a hydrogen-containing precursor; as well as The oxidized ruthenium is removed, wherein the processing area is kept plasma-free throughout the etching process and the temperature within the processing area is maintained at less than or equal to 150°C.

2. The etching method of claim 1, wherein the temperature in the processing area is maintained at or above 100°C.

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

4. The etching method of claim 1, further comprising the following additional operations: Before the oxygen-containing precursor is flowed, the substrate is brought into contact with the hydrogen-containing precursor, wherein the hydrogen-containing precursor exposes the ruthenium region.

5. The etching method of claim 1, wherein removing the oxidized ruthenium exposes additional ruthenium, and wherein the method is repeated in additional cycles.

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

7. The etching method of claim 1, wherein the pressure within the semiconductor processing chamber is maintained at a level greater than or equal to 1 Torr.

8. An etching method, comprising: This allows oxygen-containing precursors to flow into the processing area of ​​the semiconductor processing chamber; The substrate contained in the processing area is brought into contact with the oxygen-containing precursor, wherein the substrate includes an exposed ruthenium region, and wherein the contact produces ruthenium tetroxide. Particle processing is performed in the processing area of ​​the semiconductor processing chamber using an inert precursor, wherein the inert precursor includes argon or helium; The ruthenium tetroxide is brought into contact with the inert precursor. as well as The ruthenium tetroxide is removed, wherein the processing area is kept plasma-free throughout the etching process and the temperature within the processing area is maintained at less than or equal to 150°C.

9. The etching method of claim 8, wherein the temperature within the semiconductor processing chamber is maintained at less than or equal to 25°C.

10. The etching method of claim 8, wherein removing the ruthenium tetroxide exposes additional ruthenium, and wherein the method is repeated in additional cycles.

11. The etching method of claim 8, further comprising the following additional operations: Before the oxygen-containing precursor is flowed, the substrate is brought into contact with a hydrogen-containing precursor, wherein the hydrogen-containing precursor exposes the ruthenium region.

12. An etching method, comprising: A substrate disposed within a processing area of ​​a semiconductor processing chamber is brought into contact with a hydrogen-containing precursor, wherein the contact exposes ruthenium metal on the substrate; Oxygen-containing precursors are introduced into the processing area of ​​the semiconductor processing chamber; The ruthenium metal exposed on the substrate is brought into contact with the oxygen-containing precursor, wherein the contact produces ruthenium tetroxide; as well as The ruthenium tetroxide is vaporized from the surface of the ruthenium metal, wherein a certain amount of oxidized ruthenium is retained; The oxidized ruthenium is brought into contact with a hydrogen-containing precursor; as well as The oxidized ruthenium is removed, wherein the processing area is kept plasma-free throughout the etching process and the temperature within the processing area is maintained at less than or equal to 150°C.

13. The etching method of claim 12, wherein the temperature in the processing area is maintained at less than or equal to 10°C.

14. The etching method of claim 12, further comprising: The method repeats at least one additional loop.

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