System and method for removing aluminum-containing films

Abstract

Exemplary etching methods may include flowing a halogen-containing precursor into a substrate processing region of a semiconductor processing chamber. The halogen-containing precursor may be characterized by a gas density greater than or about 5 g / L. The method may include contacting a substrate housed in the substrate processing region with the halogen-containing precursor. The substrate may define an exposed area of ​​the halogen-containing material. Contact may generate aluminum halide material. The method may include flowing an etchant precursor into the substrate processing region. The method may include contacting the aluminum halide material with the etchant precursor. The method may include removing the aluminum halide material.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit and priority of U.S. Nonprovisional Application No. 17 / 018,229, filed September 11, 2020, entitled “SYSTEMS AND METHODS FORALUMINUM-CONTAINING FILM REMOVAL”, 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 aluminum-containing structures. Background Technology

[0004] Integrated circuits can be fabricated by processes that create complex patterned material layers on a substrate surface. Creating patterned material on the substrate requires a controlled method for removing exposed material. Chemical etching is used for a variety of 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, which facilitates, for example, pattern transfer processes. This etching process is considered selective for the first material. Due to the diversity of materials, circuits, and processes, etching processes selective for a variety of materials have been developed.

[0005] Based on the materials used in the process, etching processes can be called wet etching or dry etching. For example, wet etching can preferentially remove some oxide dielectrics compared to other dielectrics and materials. However, wet etching may have difficulty penetrating 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 exhibits finer remaining structure with less deformation. However, localized plasma can damage the substrate by generating an electric arc during its discharge.

[0006] Therefore, there is a need for improved systems and methods to produce high-quality devices and structures. This technology meets these and other needs. Summary of the Invention

[0007] Exemplary etching methods may include flowing a halogen-containing precursor into a substrate processing region of a semiconductor processing chamber. The halogen-containing precursor may be characterized by a gas density greater than or about 5 g / L. The method may include contacting a substrate housed in the substrate processing region with the halogen-containing precursor. The substrate may define an exposed area of ​​the halogen-containing material. Contact may generate aluminum halide material. The method may include flowing an etchant precursor into the substrate processing region. The method may include contacting the aluminum halide material with the etchant precursor. The method may include removing the aluminum halide material.

[0008] In some embodiments, the halogen-containing precursor may include a transition metal, and the etchant precursor may be or include a chlorine-containing precursor. The halogen-containing precursor may include tungsten or niobium. The aluminum-containing material may be or include alumina. The etching method may be a plasma-free etching process. The etching method may be performed at a temperature greater than or about 300°C. The etching method may be performed at a pressure greater than or about 0.1 Torr. The etching method may be performed at a pressure less than or about 50 Torr. The method may include performing a pretreatment before allowing the halogen-containing precursor to flow. The pretreatment may include contacting the substrate with a plasma containing one or more of oxygen, hydrogen, or nitrogen. The method may include performing a post-treatment after the etching method. The post-treatment may include contacting the substrate with a plasma containing one or more of oxygen, hydrogen, or nitrogen.

[0009] Some embodiments of this technology may include etching methods. The methods may include forming a process precursor plasma comprising one or more of oxygen, hydrogen, or nitrogen to generate a process plasma effluent. The methods may include flowing the process plasma effluent into a substrate processing region of a semiconductor processing chamber. The methods may include contacting a substrate housed in the substrate processing region with the process plasma effluent. The substrate may define an exposed area of ​​aluminum-containing material. The process plasma effluent may be configured to remove residues from the surface of the aluminum-containing material. The methods may include flowing a first halogen-containing material into the substrate processing region of the semiconductor processing chamber. The methods may include contacting the substrate with the first halogen-containing material. The methods may include flowing a second halogen-containing precursor into the substrate processing region of the semiconductor processing chamber. The methods may include removing aluminum-containing material.

[0010] In some embodiments, the first halogen-containing material may include a plasma effluent of a tungsten or niobium or fluorine-containing precursor. The second halogen-containing precursor may be or include boron trichloride. The method may include stopping plasma formation before allowing the first halogen-containing precursor to flow. The etching method may be performed at a temperature greater than or about 300°C. The etching method may be performed at a pressure greater than or about 0.1 Torr. The method may include performing a post-processing step after the etching method. The post-processing may include contacting the substrate with a plasma containing one or more of oxygen, hydrogen, or nitrogen.

[0011] Some embodiments of this technology may include etching methods. The method may include flowing a fluorine-containing precursor into a substrate processing region of a semiconductor processing chamber. The fluorine-containing precursor may be characterized in that its gas density is greater than or about 5 g / L. The method may include contacting a substrate housed in the substrate processing region with the fluorine-containing precursor. The substrate may define an exposed area of ​​aluminum-containing material. The method may include flowing a chlorine-containing precursor into a substrate processing region of a semiconductor processing chamber. The method may include contacting the substrate with a chlorine-containing precursor. The method may include removing aluminum-containing material. The method may include forming a processing precursor plasma comprising one or more of oxygen, hydrogen, or nitrogen to generate a processing plasma effluent. The method may include contacting the substrate with the processing plasma effluent.

[0012] In some embodiments, the fluorine-containing precursor may include tungsten or niobium, and the chlorine-containing precursor may include boron. The plasma effluent can be configured to remove residual tungsten or niobium from one or more of the substrate or semiconductor processing chamber. The etching method can be performed at a temperature greater than or about 300°C and a pressure greater than or about 0.1 Torr.

[0013] This technology offers numerous advantages over conventional systems and techniques. For example, the process allows for dry etching, which protects the features of the substrate. Additionally, the process can selectively remove the aluminum-containing film relative to other exposed material on the substrate. These and other embodiments, along with many of their advantages and features, are described in more detail below with reference to the accompanying drawings. Attached Figure Description

[0014] The nature and advantages of the disclosed technology can be further understood by referring to the remainder of the specification and drawings.

[0015] Figure 1 A top plan view of one embodiment of an exemplary processing system according to some embodiments of the present technology is shown.

[0016] Figure 2A A schematic cross-sectional view of an exemplary processing chamber according to some embodiments of the present technology is shown.

[0017] Figure 2B Some embodiments according to the present technology are shown. Figure 2A A detailed view of a portion of the processing chamber shown.

[0018] Figure 3 A bottom plan view of an exemplary nozzle according to some embodiments of the present technology is shown.

[0019] Figure 4 Exemplary operations of methods according to some embodiments of the present technology are shown.

[0020] Figures 5A to 5BA schematic cross-sectional view of etched material according to some embodiments of the present technology is shown.

[0021] Several figures in the accompanying drawings are included as schematic diagrams. It should be understood that the drawings are for illustrative purposes and should not be considered to scale unless explicitly stated otherwise. Furthermore, the drawings are provided as schematic diagrams to aid understanding, and may not include all aspects or information compared to actual representations, and may include additional or exaggerated material for illustrative purposes.

[0022] In the accompanying drawings, similar parts and / or features may have the same reference numerals. Additionally, parts of the same type may be distinguished by adding letters after the reference numerals to differentiate them. If only a first reference numeral is used in the specification, the description applies to any of the similar parts having the same first reference numeral, regardless of the letters. Detailed Implementation

[0023] Dilute acids are used in many different semiconductor processes for cleaning substrates and removing materials from them. For example, dilute hydrofluoric acid (DHF) is an effective etchant for silicon oxide, aluminum oxide, and other materials, and can be used to remove these materials from substrate surfaces. After etching or cleaning operations are complete, the acid can be dried from the wafer or substrate surface. The use of dilute hydrofluoric acid (DHF) is known as "wet" etching, and water is typically used as the diluent. Other etching processes can be used that utilize precursors delivered to the substrate. For example, plasma-enhanced processes can also selectively etch materials by using plasma-enhanced precursors to perform dry etching.

[0024] While wet etchants using aqueous solutions or water-based processes are effective for certain substrate structures, water can present challenges under various conditions. For example, using water during the etching process can cause problems when applied to substrates containing metallic materials. For instance, after a certain amount of metallization has been formed on the substrate, certain post-fabrication processes or other processes, such as recessed areas, removal of oxide dielectrics, etc., can be performed to remove oxygen-containing materials. If water is used in some way during etching, electrolytes can be generated, which, when in contact with metallic materials, can cause electrolytic corrosion between different metals, corroding or displacing metals in various processes. Additionally, due to the surface tension of water diluents, small structures can experience pattern deformation and breakage. Water-based materials also cannot penetrate some high aspect ratio features due to surface tension effects.

[0025] Plasma etching can overcome the problems associated with water-based etching, but other issues may arise. For example, alumina and other aluminum-based dielectrics have been incorporated into many semiconductor structures and exhibit dielectric properties. Due to these dielectric properties, these aluminum materials are not easily conductive. Therefore, when charged plasma species flow to these materials, charge can accumulate along the surface of the aluminum-based dielectric. Once this accumulation exceeds a critical value, voltage collapse can occur, potentially damaging the aluminum material.

[0026] This technology overcomes these problems by performing a dry etching process that can passivate a variety of materials relative to the material to be etched, and in some embodiments, the process can be performed without plasma during etching. The etching process can be performed by utilizing specific precursors that promote halogen dissociation to provide etchant materials, which can protect the surrounding structure. Furthermore, the materials and conditions used allow for improved etching compared to conventional techniques.

[0027] While the remainder of the disclosure will routinely describe specific etching processes using the disclosed techniques, it will be readily understood that the system and methods are equivalently applicable to deposition and cleaning processes that can occur in the described chambers, as well as other etching techniques including mid-stage and back-end processes, and other etching that can be performed with a variety of exposed materials (which may be sustained or substantially sustained). Therefore, this technique should not be construed as being limited to the exemplary etching processes or chambers only. Furthermore, while exemplary chambers are described as the basis for providing this technique, it should be understood that this technique can be applied to virtually any semiconductor processing chamber that allows the described operations.

[0028] Figure 1This figure shows a top view of one embodiment of a processing system 100 having deposition, etching, baking, and curing chambers according to an embodiment. In the figure, a pair of front-opening unified pods (FOUPs) 102 supply substrates of various sizes, which are received by a robotic arm 104 and placed in a low-pressure holding region 106, and then placed in one of the substrate processing chambers 108a to 108f, which are positioned in tandem segments 109a to 109c. A second robotic arm 110 is used to transport substrate wafers from the holding region 106 to the substrate processing chambers 108a to 108f and back. Each substrate processing chamber 108a to 108f can be configured to perform several substrate processing operations, including the dry etching process described herein, as well as cyclical layer deposition (CLD), atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), etching, pre-cleaning, degassing, orientation, and other substrate processes.

[0029] The substrate processing chambers 108a to 108f 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 to 108d and 108e to 108f) may be used to deposit dielectric material on the substrate, and a third pair of processing chambers (e.g., 108a to 108b) may be used to etch the deposited dielectric material. In another configuration, all three pairs of chambers (e.g., 108a to 108f) may be configured to etch dielectric films on the substrate. Any or more of the described processes may be performed in chamber(s) separate from the manufacturing systems shown in the different embodiments. Other configurations of the deposition, etching, annealing, and curing chambers for dielectric films, as considered by system 100, will be appreciated.

[0030] Figure 2AA cross-sectional view of an exemplary process chamber system 200 is shown, showing a process chamber with partitioned plasma generation regions. During film etching, process gases, such as titanium nitride, tantalum nitride, tungsten, silicon, polysilicon, silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, etc., can flow to a first plasma region 215 via a gas inlet assembly 205. The system may optionally include a remote plasma system (RPS) 201, which can process the 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 (not shown) may bypass the RPS 201 (if included).

[0031] 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 are shown, and each of these components may be included according to embodiments. The base 265 may have a heat exchange channel through which a heat exchange fluid flows to control the temperature of the substrate, and the heat exchange fluid may be operable to heat and / or cool the substrate or wafer during processing operations. An embedded resistive heater element may also be used to resistively heat the wafer support disk 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 above or about 1100°C.

[0032] Panel 217 may be pyramidal, conical, or another similar structure, extending from a narrow top portion to a wide bottom portion. Panel 217 may also be flat, as shown, and include multiple through channels for distributing process gases. Depending on the use of RPS 201, plasma-generating gases and / or plasma-excited species can pass through multiple holes in panel 217 (e.g., Figure 2B (as shown), to deliver more evenly into the first plasma region 215.

[0033] An exemplary configuration may include opening a gas inlet assembly 205 into a gas supply region 258, which is separated from a first plasma region 215 by a panel 217, such that gas / species flows through an aperture in the panel 217 into the first plasma region 215. Selectable structural and operational features may be chosen to 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. A conductive top portion of the panel 217 or chamber and a nozzle 225 are shown, with an insulating ring 220 positioned between the features, allowing 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 (CCP) in the first plasma region. A baffle (not shown) may be additionally located in the first plasma region 215 or otherwise coupled to the gas inlet assembly 205 to influence the flow of fluid through the gas inlet assembly 205 into the region.

[0034] The gas suppressor 223 may comprise a plate or other geometry defining a plurality of orifices through the structure, the orifices being configured to suppress the migration of charged ionic species out of the first plasma region 215 while allowing uncharged neutral or radical species to pass through the ion suppressor 223 into the activation gas delivery region between the suppressor and the nozzle. In embodiments, the ion suppressor 223 may comprise a porous plate with various orifice configurations. These uncharged species may include highly reactive species, which are delivered together with a low-reactive carrier gas via the orifices. As noted above, migration of ionic species through the orifices can be reduced, and in some cases, migration of ionic species through the orifices can be completely suppressed. Controlling the amount of ionic species passing through the ion suppressor 223 can advantageously provide greater control over the gas mixture contacting the underlying wafer substrate, thereby further enhancing 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 an alternative embodiment where deposition is performed, adjusting the ion concentration of the gas mixture can also adjust the balance between conformal and flow deposition of the dielectric material.

[0035] Multiple orifices in ion suppressor 223 can be configured to control the passage of activating gas (i.e., ions, free radicals, and / or neutral species) through ion suppressor 223. For example, the aspect ratio or diameter-to-length ratio of the orifices and / or the geometry of the orifices can be controlled to reduce the flow of charged ions in the activating gas through ion suppressor 223. The orifices in ion suppressor 223 may include a trapezoidal 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 ion species toward nozzle 225. An adjustable electrical bias voltage can also be applied to ion suppressor 223 as an additional means of controlling the flow of ion species through the suppressor.

[0036] Ion suppressor 223 can be used to reduce or eliminate the amount of ionic charged species traveling from the plasma generation region towards the substrate. Uncharged neutral species and free radical species can still pass through openings in the ion suppressor to react with the substrate. It should be noted that complete elimination of ionic charged species in the reaction region surrounding the substrate may not be performed in the embodiments. In some cases, ionic species are expected to reach the substrate in order to perform etching and / or deposition processes. In these cases, the ion suppressor can help control the concentration of ionic species in the reaction region to a level conducive to the process.

[0037] The combination of nozzle 225 and ion suppressor 223 allows plasma present in the first plasma region 215 to avoid directly exciting the gas in the substrate processing region 233, while still allowing excited species 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 substrate 255 being etched. This advantageously protects multiple complex structures and films patterned on the substrate, which could be damaged, dislodged, or otherwise warped if directly exposed to the generated plasma. Additionally, the etching rate of oxide species can be increased when plasma is allowed to contact the substrate or approach the substrate level. Therefore, if the exposed area of ​​the material is oxide, this material can be further protected by maintaining the plasma at the distal end of the substrate.

[0038] The processing system may further include a power supply 240 electrically coupled to the processing chamber, which supplies electrical 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 may be configured to deliver an adjustable amount of power to the chamber depending on the process being performed. Such a configuration allows for the use of adjustable plasma in the performed process. Unlike remote plasma units that typically have an on / off function, adjustable 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, such as dissociating precursors in a specific manner to enhance the etched profiles produced by those precursors.

[0039] 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 the inflow of, for example, fluorine-containing precursors 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 independently or in combination with the 13.56 MHz frequency.

[0040] Figure 2B A detailed view 253 shows features that affect 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 delivered 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 after crossing panel 217, it can partially or completely prevent process gas from flowing back into gas supply region 258.

[0041] The gas distribution assembly (e.g., nozzle 225) used in the treatment chamber section 200 may be referred to as a dual-channel showerhead (DCSH), and Figure 3The described embodiments are described in detail. A dual-channel nozzle can be provided for etching processes, which allows the etchant outside the processing area 233 to provide limited interaction with the chamber components and each other before the etchant is delivered to the processing area.

[0042] Nozzle 225 may include an upper plate 214 and a lower plate 216. The plates may be coupled to define a volume 218 between them. This coupling may provide 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 such that fluid enters the volume 218 through the lower plate 216 only via the second fluid passage 221, and the first fluid passage 219 may be fluidly isolated from the volume 218 between the plates and the second fluid passage 221. Fluid access to the volume 218 may be achieved through one side of nozzle 225.

[0043] Figure 3 This is a bottom view of a nozzle 325 for use 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 the precursor through the nozzle 225. The orifices 375 (showing a view of the second fluid channel 221) can be distributed substantially uniformly on the surface of the nozzle, or even within the through-hole 365, and can contribute to providing a more uniform mixing of the precursor as it exits the nozzle compared to other configurations.

[0044] Exemplary methods, including etching methods, can be performed using the chambers discussed above. (Go to...) Figure 4 This illustrates exemplary operations in method 400 according to an embodiment of the present technology. Method 400 includes one or more operations prior to the start of the method, including front-end processing, deposition, gate formation, etching, polishing, cleaning, or any other operations that may be performed prior to the described 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 of the operations are described to provide a broader range of the processes performed, but this is not critical to the technology, or the operations may be performed by alternative methods discussed further below. Method 400 may describe Figures 5A to 5B The operations shown schematically will be described in conjunction with the operations of method 400. Figures 5A to 5B It should be understood that the accompanying drawings show only partial schematic diagrams, and the substrate may contain any number of other materials and features, having the various properties and aspects illustrated in the drawings.

[0045] Method 400 may or may not involve optional operations to advance the semiconductor structure to a specific manufacturing operation. It should be understood that operations such as... Figure 5AMethod 400 is performed on any number of semiconductor structures or substrates 505 shown, including exemplary structures on which oxide removal operations can be performed. Exemplary semiconductor structures may include trenches, vias, or other recessed features that may include one or more exposed materials. For example, an exemplary substrate may contain silicon or some other semiconductor substrate material and an interlayer dielectric material through which recesses, trenches, vias, or isolation structures may be formed. The exposed material at any point during the etching process may be or include metallic materials, such as gate, dielectric, contact, transistor materials, or any other material that can be used in semiconductor processes. In some embodiments, the exemplary substrate may include an aluminum-containing material 515, such as alumina or some other aluminum-containing dielectric. The aluminum-containing material may be exposed relative to one or more other materials 510 including metals, other dielectrics including silicon oxide or silicon nitride, or several other semiconductor materials (relative to the removal of the aluminum-containing material, such as titanium, tantalum nitride, or other materials).

[0046] It should be understood that the structures described are not intended to be limiting and similarly include any of several other semiconductor structures, including those containing aluminum. Other exemplary structures may include two-dimensional and three-dimensional structures common in semiconductor manufacturing, wherein aluminum-containing materials, such as alumina, are removed relative to one or more other materials, because this technique can selectively remove aluminum-containing materials relative to other exposed materials, such as silicon-containing materials or any of the other materials discussed elsewhere herein. Furthermore, while high aspect ratio structures can benefit from this technique, it can be equally applied to low aspect ratio and other structures.

[0047] For example, the material layers according to this technology may be characterized by any aspect ratio of the structure, but in some embodiments, the material may be characterized by a larger aspect ratio, which may not allow for adequate etching using conventional techniques or methods. For example, in some embodiments, the aspect ratio of any layer of the exemplary structure may be greater than or about 10:1, greater than or about 20:1, greater than or about 30:1, greater than or about 40:1, greater than or about 50:1, or greater. Additionally, each layer may be characterized by a smaller width or thickness, less than or about 100 nm, less than or about 80 nm, less than or about 60 nm, less than or about 50 nm, less than or about 40 nm, less than or about 30 nm, less than or about 20 nm, less than or about 10 nm, less than or about 50 nm, less than or about 1 nm, or less, including any fraction of any of the stated numbers, such as 20.5 nm, 1.5 nm, etc. This combination of high aspect ratio and minimal thickness can be challenging for many conventional etching operations, or require very long etching times to remove layers across a limited width, either vertically or horizontally. Furthermore, conventional techniques may also damage or remove additional exposed layers.

[0048] In one embodiment, method 400 may be performed to remove exposed aluminum-containing material, but in embodiments of the art, any number of oxides or aluminum-containing materials may be removed from any number of structures. The method may include specific operations for removing the aluminum-containing material and may include one or more optional operations for preparing or processing the aluminum-containing material. For example, an exemplary substrate structure may have previous processing residues, such as aluminum oxide, on the film to be removed. For example, residual photoresist or byproducts from previous treatment may remain on the aluminum oxide layer. These materials may prevent the penetration of aluminum oxide or may interact with the etchant differently than a clean aluminum oxide surface, which may hinder one or more aspects of etching. Therefore, in some embodiments, optional pretreatment of the aluminum-containing film or material may occur in optional operation 405. Exemplary pretreatment operations may include heat treatment, wet treatment, or plasma treatment, which may be performed, for example, in chamber 200 and any number of chambers that may be included on system 100 described above.

[0049] In an exemplary plasma process, a remote or local plasma can be developed from precursors intended to interact with residues in one or more ways. For example, using a chamber such as chamber 200 described above, a remote or local plasma can be generated from one or more precursors. For example, an oxygen-containing precursor, a hydrogen-containing precursor, a nitrogen-containing precursor, a helium-containing precursor, or some other precursor can be flowed into a remote plasma region or processing region, where it can come into contact with the plasma. A plasma effluent can be flowed to a substrate, and the plasma effluent can contact the residual material. Depending on the material to be removed to expose aluminum-containing material, the plasma process can be a physical or chemical process. For example, the plasma effluent can flow to contact and physically remove the residue (e.g., by sputtering operations), or the precursor can flow to interact with the residue to generate volatile byproducts, which can be removed from the chamber.

[0050] Exemplary precursors used in the pretreatment may be or include hydrogen, hydrocarbons, water vapor, alcohols, hydrogen peroxide, or any material including hydrogen as will be understood by those skilled in the art. Exemplary oxygen-containing precursors may include molecular oxygen, ozone, nitrous oxide, nitric oxide, or other oxygen-containing materials. Nitrogen may also be used, or a combination of precursors having one or more of hydrogen, oxygen, and / or nitrogen may be used to remove specific residues. Once residues or byproducts are removed, a clean alumina surface can be exposed for etching.

[0051] Method 400 may include, at operation 410, flowing a halogen-containing precursor, including a first halogen-containing precursor, into a substrate processing region of a semiconductor processing chamber housing the described substrate or another substrate. The halogen-containing precursor may flow through a remote plasma region of the processing chamber, such as region 215 described above, but in some embodiments, method 400 may not use plasma effluent during the etching operation. For example, method 400 may flow a fluorine-containing or other halogen-containing precursor into the substrate without exposing the precursor to plasma, and may perform the removal of aluminum-containing material without generating plasma effluent. In some embodiments, the halogen-containing precursor may be plasma-enhanced, which may occur in a remote plasma region to protect the material on the substrate from contact with plasma effluent. The halogen-containing precursor may contact the semiconductor substrate, including exposed aluminum-containing material, and may generate a fluorinated material, such as aluminum fluoride or aluminum halide, which may remain on the semiconductor substrate. In some embodiments, the halogen-containing precursor may apply one or more fluorine atoms while accepting one or more oxygen atoms. Some halogenated precursors, such as plasma-enhanced precursors, can provide fluorine radicals, while other plasma radicals can accept oxygen from the membrane.

[0052] Following the fluorination operation, an etchant precursor can be introduced into the processing area at operation 415. In some embodiments, the etchant precursor may be a second halogen-containing precursor and may include the same or different halogens as the first halogen-containing precursor. The etchant precursor may be further substituted to produce aluminum byproducts, which may be volatile under processing conditions and may be segregated from the substrate. Thus, as Figure 5B As shown, at operation 420, the etchant precursor can etch or remove aluminum material.

[0053] As noted above, this technique can be performed in etching operations 410 to 420 without plasma development. Plasma-free removal can be performed by using specific precursors and performing etching under certain process conditions, and the removal can also be dry etching. Therefore, techniques according to this aspect can be performed to remove alumina and high aspect ratio features from narrow features, as well as thin dimensions that may otherwise be unsuitable for wet etching. Optional operations can be performed to remove residues from the substrate or chamber, and post-processing can be included at optional operation 425. Post-processing may include operations similar to pre-processing and may include any of the precursors or operations discussed above with respect to pre-processing. In some embodiments, post-processing may remove residual transition metal from the substrate or chamber. It should be understood that while pre-processing and / or post-processing operations may include plasma generation and delivery of plasma effluent to the substrate, plasma may not be formed during the etching operation. For example, in some embodiments, no plasma is generated when a halogen-containing precursor or precursor is delivered to the processing chamber. Additionally, in some embodiments, the etching precursor may be hydrogen-free, and the etching method may not include a hydrogen-containing precursor during etching, but a hydrogen-containing precursor may be used during either or both of optional pre- or post-processing operations.

[0054] The precursor during either of the two-step operations may include a halogen-containing precursor, and in some embodiments may include one or more of fluorine or chlorine. The specific precursor may be based on its bonding or stability. For example, in some embodiments, the first halogen-containing precursor may include a transition metal and / or be characterized by a specific gas density. The transition metal may include any transition metal capable of bonding with a halogen and capable of dissociating under the operating conditions discussed above. Exemplary transition metals may include tungsten, niobium, or any other material, and may include a transition metal- and halogen-containing precursor characterized by a gas density greater than or about 3 g / L, and characterized by gas densities greater than or about 4 g / L, greater than or about 5 g / L, greater than or about 6 g / L, greater than or about 7 g / L, greater than or about 8 g / L, greater than or about 9 g / L, greater than or about 10 g / L, greater than or about 11 g / L, greater than or about 12 g / L, greater than or about 13 g / L, or higher.

[0055] These precursors are characterized by relatively high thermal and chemical stability due to the bonding properties between heavy metals and halogens. The precursors may also be characterized by transition metals, which are characterized by relatively low resistivity, further promoting bond stability at lower temperatures and readily dissociating at higher temperatures. Therefore, the material may be characterized by a resistivity of less than or about 50 μO·cm, and may be characterized by resistivity of less than or about 40 μO·cm, less than or about 30 μO·cm, less than or about 20 μO·cm, less than or about 15 μO·cm, less than or about 10 μO·cm, less than or about 5 μO·cm, or even smaller. The precursors may also include any number of carrier gases, which may include nitrogen, helium, argon, or other rare, inert, or useful precursors.

[0056] Some exemplary precursors incorporating the described properties may include tungsten hexafluoride, tungsten pentachloride, niobium tetrachloride, or other transition metal halides, as well as other halides including hydrogen fluoride, nitrogen trifluoride, or any organofluorine compound. Precursors may also be flowed together in various combinations. In some embodiments, nitrogen trifluoride or some other fluorinated precursor may be delivered to a remote plasma region using hydrogen and enhanced plasma to produce a fluorinated surface of aluminum in a first operation. Etching precursors according to some embodiments of the present technology may specifically comprise heavy metal halides, characterized by stability under atmospheric conditions, wherein they dissociate relatively readily at elevated temperatures. For example, exemplary precursors may be characterized by relatively weak bonding at higher temperatures, which may allow control over the exposure of alumina to halogen etchants.

[0057] As a non-limiting example, tungsten hexafluoride can readily accept one or two fluorine atoms at higher temperatures and, for example, accept oxygen atoms from alumina, and be maintained in the gas phase. Thus, tungsten oxyfluoride can be developed as a reaction byproduct, which can be gaseous molecules and can be extracted or removed from the processing chamber. Since aluminum fluoride may not be volatile, chlorine-containing, bromine-containing, or iodine-containing precursors (any of which may include boron, titanium, tin, molybdenum, tungsten, or niobium) can be used to apply chlorine, bromine, or iodine, and accept fluorine at the same temperature. Although chlorine, bromine, or iodine may not be readily applied relative to alumina, the material can be applied to aluminum fluoride, and the etchant precursor can accept fluorine, producing two volatile components, including aluminum chloride, which can be expelled from the processing chamber. Thus, the process can remove alumina under processing conditions configured to exchange fluorine and oxygen between the etchant and the exposed surface, followed by the exchange of chlorine with fluorine, producing volatile aluminum byproducts, and maintaining most of the tungsten and etchant precursor in vapor form. Therefore, this technique similarly incorporates tungsten and other heavy metals with limited or virtually no interaction with the process, while simultaneously delivering halogens to the material to be etched. Because the delivery is controlled, tungsten oxide and other metal halides may not be etched or interact with other exposed surfaces to a minimum, while alumina is easily removed, resulting in enhanced selectivity compared to conventional techniques.

[0058] Processing conditions can influence and promote etching according to this technique. Since the etching reaction can be based on the thermal dissociation of halogens from transition metals, the temperature can depend at least in part on the specific halogens and / or transition metals of the precursors that trigger dissociation. As shown, etching begins or increases when the temperature is above or approximately 300°C, which can indicate the dissociation of the precursors and / or the activation of the reaction with alumina. Further increases in temperature can further promote dissociation, as well as the reaction with alumina.

[0059] Therefore, in some embodiments of this technology, the etching method can be performed at a substrate, base, and / or chamber temperature above or about 300°C, and at temperatures above or about 350°C, above or about 400°C, above or about 450°C, above or about 500°C, or higher. The temperature can also be maintained at any temperature within these ranges, smaller ranges encompassed by these ranges, or any of these ranges. In some embodiments, the method can be performed on a substrate that may have multiple resulting features, which can generate a thermal budget. Therefore, in some embodiments, the method can be performed at temperatures below or about 800°C, and at temperatures below or about 750°C, below or about 700°C, below or about 650°C, below or about 600°C, below or about 550°C, below or about 500°C, or lower.

[0060] The temperature within the chamber can also affect the operations performed, as well as the temperature at which halogens dissociate from the transition metal. Therefore, in some embodiments, the pressure can be maintained below approximately 50 Torr, below or approximately 40 Torr, below or approximately 30 Torr, below or approximately 25 Torr, below or approximately 20 Torr, below or approximately 15 Torr, below or approximately 10 Torr, below or approximately 9 Torr, below or approximately 8 Torr, below or approximately 7 Torr, below or approximately 6 Torr, below or approximately 5 Torr, below or approximately 4 Torr, below or approximately 3 Torr, below or approximately 2 Torr, below or approximately 1 Torr, below or approximately 0.1 Torr, or lower. The pressure can also be maintained within these ranges, smaller ranges encompassed by these ranges, or any pressure between these ranges. In some embodiments, etching can be promoted, and etching begins when the pressure increases to above approximately 1 Torr. Additionally, as the pressure continues to increase, etching may increase to a certain point, then begin to decrease, and eventually stop when the pressure continues to increase.

[0061] Not limited to any particular theory, the pressure within the chamber can affect the processing of the precursors described above. At low pressures, flow on the substrate can be reduced, and dissociation can be similarly reduced. As pressure increases, the interaction between the etchant precursor and the substrate can increase, which can increase the reaction and etching rates. However, as pressure continues to increase, recombination of dissociated halogen atoms with heavy metal alkalis can increase due to the relative stability of molecules. Therefore, the precursor can be effectively withdrawn from the chamber without reacting with the substrate. Additionally, as pressure continues to increase, interactions with the alumina surface can be suppressed, or the byproduct aluminum fluoride can be reintroduced into the etched film, further limiting removal. Therefore, in some embodiments, the pressure within the processing chamber can be maintained below or approximately 10 Torr.

[0062] The flow rate of the halogen-containing precursor can be adjusted (including in-situ adjustment) to control the etching process. For example, the flow rate of the halogen-containing precursor can be decreased, maintained, or increased during the removal operation. By increasing the flow rate of the halogen-containing precursor, the etching rate can be increased to the saturation point. During any of the operations of method 400, the flow rate of the fluorine-containing precursor can be between about 5 sccm and about 1000 sccm. Alternatively, the flow rate of the halogen-containing precursor can be maintained at less than or about 900 sccm, less than or about 800 sccm, less than or about 700 sccm, less than or about 600 sccm, less than or about 500 sccm, less than or about 400 sccm, less than or about 300 sccm, less than or about 200 sccm, less than or about 100 sccm, or less. The flow rate can also be between any of these described flow rates, or within a smaller range encompassed by any of these figures.

[0063] To further enhance control over the etching rate, in some embodiments, halogen-containing precursors can be pulsed in input, and the halogen-containing precursors can be delivered continuously or in a series of pulses during the etching process, the series of pulses being either continuous or time-varying. The pulse delivery is characterized by a first time period of halogen-containing precursor flow and a second time period of pause or cessation of the halogen-containing precursor flow. The time periods of any pulse operation can be the same or different from each other, and any one time period can be longer. In embodiments, the executable time period or continuous precursor flow can be greater than or approximately 1 second, greater than or approximately 2 seconds, greater than or approximately 3 seconds, greater than or approximately 4 seconds, greater than or approximately 5 seconds, greater than or approximately 6 seconds, greater than or approximately 7 seconds, greater than or approximately 8 seconds, greater than or approximately 9 seconds, greater than or approximately 10 seconds, greater than or approximately 11 seconds, greater than or approximately 12 seconds, greater than or approximately 13 seconds, greater than or approximately 14 seconds, greater than or approximately 15 seconds, greater than or approximately 20 seconds, greater than or approximately 30 seconds, greater than or approximately 45 seconds, greater than or approximately 60 seconds, or longer. The time can also be any smaller range encompassed by any of these ranges. In some embodiments, the etching rate can be increased when the delivery of the precursor occurs for a longer period of time.

[0064] By performing operations according to embodiments of the present technology, alumina or other aluminum-containing materials can be selectively etched relative to other materials containing other oxides. For example, the present technology can selectively etch alumina relative to exposed areas of metals, dielectrics including silicon-containing materials (including silicon oxide), or other materials. Embodiments of the present technology can etch alumina relative to any of silicon oxide or other materials at a rate of at least about 20:1, and can etch alumina relative to silicon oxide or the other indicated materials with selectivity greater than or about 25:1, greater than or about 30:1, greater than or about 50:1, greater than or about 100:1, greater than or about 150:1, greater than or about 200:1, greater than or about 250:1, greater than or about 300:1, greater than or about 350:1, greater than or about 400:1, greater than or about 450:1, greater than or about 500:1, or higher. For example, etching performed according to some embodiments of the present technology can etch aluminum oxide while substantially or substantially maintaining silicon oxide or other materials, such as silicon, titanium, tantalum or other nitrides.

[0065] Selectivity can be based in part on the precursors used and their ability to dissociate within a more controlled temperature range. For example, conventional precursors (including nitrogen trifluoride) may not readily dissociate at operating pressures and temperatures below or around 500°C, and are also characterized by a slower reaction rate with the material to be removed, which can increase the exposure time of other materials on the substrate and potentially increase the removal of those materials. Therefore, conventional dry etchants may not produce the etch selectivity of embodiments of the present invention. Similarly, because wet etchants readily remove silicon oxide, they may also not be able to selectively etch at rates comparable to embodiments of the present invention.

[0066] The methods discussed above allow for the removal of aluminum-containing materials relative to several other exposed materials. Improved alumina etching can be performed using transition metals as described above, which offers increased selectivity compared to conventional techniques and improved etching of recesses in fine-pitch features.

[0067] In the foregoing description, numerous details have been set forth for illustrative purposes in order to understand the 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 in the presence of others.

[0068] While several embodiments have been disclosed, those skilled in the art will understand that modifications, alternative constructions, and equivalents can be used without departing from the spirit of the embodiments. Furthermore, many known processes and elements have not been described to avoid unnecessarily obscuring the present technology. Therefore, the above description should not be considered to limit the scope of the present technology. Additionally, while methods or processes are described herein in sequence or step-by-step order, it should be understood that operations may be performed simultaneously or in a different order than listed.

[0069] Where a numerical range is provided, it should be understood that, unless the context explicitly specifies otherwise, each intermediate value between the upper and lower limits of this range, down to the smallest fraction of the lower limit unit, is also specifically disclosed. This encompasses any narrower range between any stated or unstated intermediate value and any other stated or intermediate value within the stated range. The upper and lower limits of those narrower ranges may be independently included in or excluded from the range, and this technique also covers each range (where neither the upper nor lower limit is included in the smaller range, or one or both are included in the smaller range) that is limited by the specific excluded limit value within the stated range. Where the stated range includes one or both of the limit values, ranges excluding one or both of the included limit values ​​are also included.

[0070] As used herein and in the appended claims, unless the context clearly indicates otherwise, the singular forms “a”, “an”, and “the” include plural references. Thus, for example, reference to “a precursor” includes multiple such precursors, and reference to “a layer” includes reference to one or more layers and their equivalents known to those skilled in the art, and so on.

[0071] Furthermore, when used in this specification and the appended claims, the terms “comprise(s)”, “comprising”, “contain(s)”, “containing”, “include(s)”, and “include(s)” are intended to indicate the presence of the described feature, integer, component, or operation, but do not exclude the presence or addition of one or more other features, integers, components, operations, behaviors, or groups.

Claims

1. An etching method, the etching method comprising: A halogen-containing precursor is fed into a substrate processing area of ​​a semiconductor processing chamber, wherein the halogen-containing precursor is characterized by a gas density greater than or equal to 5 g / L. The substrate contained in the substrate processing area is contacted with the halogen-containing precursor, wherein the substrate defines an exposed area of ​​aluminum-containing material, and wherein the contact generates aluminum halide material. An etchant precursor is fed into the substrate processing area, wherein the etchant precursor comprises a heavy metal halide. The aluminum halide material is contacted with the etchant precursor; as well as The aluminum halide material is removed, thereby selectively etching the aluminum-containing material relative to other materials.

2. The etching method of claim 1, wherein the halogen-containing precursor comprises a transition metal, and wherein the etchant precursor comprises a chlorine-containing precursor.

3. The etching method of claim 2, wherein the halogen-containing precursor comprises tungsten or niobium.

4. The etching method of claim 1, wherein the aluminum-containing material comprises aluminum oxide.

5. The etching method of claim 1, wherein the etching method comprises a plasma-free etching process.

6. The etching method of claim 1, wherein the etching method is performed at a temperature greater than or equal to 300°C.

7. The etching method of claim 1, wherein the etching method is performed under a pressure greater than or equal to 0.1 Torr.

8. The etching method of claim 7, wherein the etching method is performed under a pressure of less than or equal to 50 Torr.

9. The etching method of claim 1, further comprising: performing a pretreatment before allowing the halogen-containing precursor to flow, wherein the pretreatment comprises: contacting the substrate with a plasma comprising one or more of oxygen, hydrogen, or nitrogen.

10. The etching method of claim 1, further comprising: performing a post-processing step after the etching method, wherein the post-processing step comprises: contacting the substrate with a plasma comprising one or more of oxygen, hydrogen, or nitrogen.

11. An etching method, the etching method comprising: Forming a plasma containing one or more of oxygen, hydrogen, or nitrogen as a processing precursor to produce a processing plasma effluent; The processing plasma outflow is directed to the substrate processing area of ​​the semiconductor processing chamber; The processed plasma effluent is used to contact the substrate contained in the substrate processing area, wherein the substrate defines an exposed area of ​​aluminum-containing material, and wherein the processed plasma effluent is configured to remove residues from the surface of the aluminum-containing material. The first halogen-containing material is allowed to flow into the substrate processing area of ​​the semiconductor processing chamber; The substrate is contacted with the first halogen-containing material; A second halogen-containing precursor is fed into the substrate processing region of the semiconductor processing chamber, wherein the second halogen-containing precursor comprises a heavy metal halide; and The aluminum-containing material is removed, thereby selectively etching the aluminum-containing material relative to other materials.

12. The etching method of claim 11, wherein the first halogen-containing material comprises a plasma effluent of a tungsten or niobium or fluorine-containing precursor, and wherein the second halogen-containing precursor further comprises boron trichloride.

13. The etching method of claim 11, further comprising: stopping the plasma formation before allowing the first halogen-containing precursor to flow.

14. The etching method of claim 11, wherein the etching method is performed at a temperature greater than or equal to 300°C.

15. The etching method of claim 11, wherein the etching method is performed under a pressure greater than or equal to 0.1 Torr.

16. The etching method of claim 11, further comprising: performing a post-processing step after the etching method, wherein the post-processing step comprises: contacting the substrate with a plasma comprising one or more of oxygen, hydrogen, or nitrogen.

17. An etching method, the etching method comprising: A fluorine-containing precursor is fed into a substrate processing area of ​​a semiconductor processing chamber, wherein the fluorine-containing precursor is characterized by a gas density greater than or equal to 5 g / L. The substrate contained in the substrate processing area is contacted with the fluorine-containing precursor, wherein the substrate defines an exposed area of ​​aluminum-containing material. A chlorine-containing precursor is fed into the substrate processing region of the semiconductor processing chamber, wherein the chlorine-containing precursor includes a heavy metal halide; The substrate is contacted with the chlorine-containing precursor; The aluminum-containing material is removed, thereby selectively etching the aluminum-containing material relative to other materials; Forming a plasma containing one or more of oxygen, hydrogen, or nitrogen as a processing precursor to produce a processing plasma effluent; and The processed plasma effluent is used to contact the substrate.

18. The etching method of claim 17, wherein the fluorine-containing precursor comprises tungsten or niobium, and wherein the chlorine-containing precursor further comprises boron.

19. The etching method of claim 18, wherein the processing plasma effluent is configured to remove residual tungsten or niobium from one or more of the substrate or the semiconductor processing chamber.

20. The etching method of claim 17, wherein the etching method is performed at a temperature greater than or equal to 300°C and at a pressure greater than or equal to 0.1 Torr.

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