Systems and methods for selective metal-containing material removal

Abstract

Example semiconductor processing methods may include providing an etchant precursor and an oxygen-containing precursor to a processing region of a semiconductor processing chamber. A substrate may be disposed within the processing region. The substrate may define an exposed metal-containing material region and an exposed second material region. These methods may include contacting the substrate with the etchant precursor and the oxygen-containing precursor. These methods may include selectively removing at least a portion of the metal-containing material relative to the second material.

Description

[Technical Field]

[0001] This application claims priority to U.S. non-provisional application No. 19 / 061,200, filed February 24, 2025, and claims interest and priority to U.S. provisional application No. 63 / 568,294, filed March 21, 2024, which is incorporated herein by reference in its entirety for all purposes.

[0002] This technology relates to semiconductor manufacturing processes and equipment. More specifically, this technology relates to the selective etching of metallic materials. [Previous Technology]

[0003] Integrated circuits are realized by processes that can create finely patterned material layers on the surface of a substrate. Creating patterned material on a substrate requires controlled methods for removing exposed material. Chemical etching is used for a variety of purposes, including transferring photoresist patterns to underlying layers, thinning layers, or thinning the lateral dimensions of features already present on a surface. It is often desirable to have an etching process that can etch one material more quickly than another to facilitate processes such as pattern transfer. Such etching processes are called selective for the first material. Due to the diversity of materials, circuits, and processes, selective etching processes for various materials have been developed.

[0004] The etching process can be referred to as wet etching or dry etching, depending on the materials used in the process. For example, wet etching may prefer to remove certain oxide dielectrics without removing other dielectrics and materials. However, wet processes may encounter difficulties penetrating certain narrow trenches and sometimes deform the remaining material. Dry etching, performed by localized plasma generated in the substrate processing area, can penetrate narrower trenches and exhibits less deformation of the fragile remaining structure. However, localized plasma may damage the substrate by generating an electric arc during discharge.

[0005] Therefore, there is a need for improved systems and methods to produce high-quality components and structures. These and other needs are addressed by this technology. [Summary of the Invention]

[0006] Example semiconductor processing methods may include providing an etchant precursor and an oxygen-containing precursor to a processing region of a semiconductor processing chamber. A substrate may be disposed within the processing region. The substrate may define an exposed metal-containing material region and an exposed second material region. These methods may include contacting the substrate with the etchant precursor and the oxygen-containing precursor. These methods may include selectively removing at least a portion of the metal-containing material relative to the second material.

[0007] In some embodiments, the etchant precursor may be or include a halogen-containing precursor. The etchant precursor may be or include a chlorine-containing precursor. The chlorine-containing precursor may be or include boron trichloride (BCl3). The oxygen-containing precursor may be or include diatomic oxygen (O2). The metal-containing material may be or include tungsten, molybdenum, niobium, or titanium. The metal-containing material may also include oxygen, nitrogen, or both. Removal of the portion of the metal-containing material can be performed without plasma. Removal of the portion of the metal-containing material can be performed at a temperature below or about 550°C. Removal of the portion of the metal-containing material can be performed at a pressure above or about 0.5 Torr.

[0008] Some embodiments of this technology may include semiconductor processing methods. These methods may include providing a chlorine-containing precursor and an oxygen-containing precursor to a processing region of a semiconductor processing chamber. A substrate may be disposed within the processing region. The substrate may define an exposed metal-containing material region and an exposed second material region. These methods may include contacting the substrate with the chlorine-containing precursor and the oxygen-containing precursor. These methods may include selectively removing at least a portion of the metal-containing material relative to the second material. The removal of this portion of the metal-containing material may be performed without plasma.

[0009] In some embodiments, the flow rate ratio of the oxygen-containing precursor to the chlorine-containing precursor may be greater than or about 2:1. The second material may be or include hafnium oxide, alumina, silicon oxide, silicon nitride, silicon, germanium silicon, or a carbon hard mask. These methods may include providing an inert precursor together with the chlorine-containing precursor and the oxygen-containing precursor. Removal of the metal-containing material from this portion may be carried out at a temperature above or about 250°C. Removal of the metal-containing material from this portion may be carried out at a pressure above or about 30 Torr.

[0010] Some embodiments of this technology may include semiconductor processing methods. These methods may include providing an etchant precursor and an oxygen-containing precursor to a processing region of a semiconductor processing chamber. A substrate may be disposed within the processing region. The substrate may define an exposed metal-containing material region and an exposed second material region. The flow rate of the oxygen-containing precursor may be greater than the flow rate of the etchant precursor. These methods may include contacting the substrate with the etchant precursor and the oxygen-containing precursor. These methods may include removing at least a portion of the metal-containing material relative to the second material with a selectivity greater than or about 10:1.

[0011] In some embodiments, the etchant precursor may be or include boron trichloride (BCl3) or tungsten hexafluoride (WF6), while the oxygen-containing precursor may be or include diatomic oxygen (O2). The metal-containing material may be or include tungsten, molybdenum, niobium, or titanium. Removal of this portion of the metal-containing material can be performed without plasma.

[0012] This technology may offer many advantages over conventional systems and techniques. For example, these processes can allow for plasma-free etching, thereby protecting features or materials on the substrate. Furthermore, these processes can selectively remove metallic materials relative to other exposed materials on the substrate without depositing fluorine-containing residues on the substrate. These and other embodiments, along with their many advantages and features, will be described in more detail in the following description and figures.

Implementation Method

[0022] Diluted acids can be used in many different semiconductor processes to clean substrates and remove materials from them. For example, diluted hydrofluoric acid ("DHF") can effectively etch silicon oxide, aluminum oxide, titanium oxide, and other materials and can be used to remove these materials from the substrate surface. After the etching or cleaning operation is complete, the acid may dry off from the wafer or substrate surface. Using DHF can be referred to as "wet" etching, where the diluent is typically water. Other etching processes can be used that utilize precursors delivered to the substrate. For example, plasma-enhanced processes can also selectively etch materials using plasma-enhanced precursors to achieve dry etching.

[0023] While wet etchants using aqueous solutions or water-based processes may be effective for certain substrate structures, water can present challenges under a variety of conditions. For example, the use of water during etching can cause problems on substrates containing metallic materials. For instance, certain subsequent manufacturing processes, such as recessed areas, removal of oxide dielectrics, or other processes that remove oxygen-containing materials, may be performed after a certain amount of metallization has been formed on the substrate. If water is used in some way during etching, electrolytes may be generated, which can lead to electrochemical corrosion between different metals when they come into contact with metallic materials, and the metallic materials may be corroded or displaced in various processes. In addition, microstructures may experience pattern deformation and collapse due to the surface tension of the water diluent. Water-based materials may also be unable to penetrate certain high aspect ratio features due to surface tension effects. Plasma etching may overcome the problems associated with water-based etching, but additional problems may arise. For example, reactive ion etching processes may expose metallic materials to ionic activity, and this bombardment may damage the structure and affect electrical properties. Furthermore, some plasma etching may result in poor selectivity because other materials in the material being etched may also be removed. In addition, some etching operations may leave residues from the precursors used, which could affect the performance of the final components.

[0024] This technology overcomes these problems by performing a dry etching process, which can be carried out thermally or without plasma. Furthermore, this technology can use certain specific halogen precursors, such as chlorine-containing precursors, which may leave less residue after etching. By utilizing specific precursors and / or processing conditions to promote halogen dissociation to provide etchant material, an etching process that can protect the surrounding structure is performed. Moreover, the materials and conditions used can achieve improved etching, such as etching rate and selectivity, compared to conventional techniques.

[0025] Although the following disclosures will frequently identify specific etching processes using the disclosed techniques, it will be apparent that these systems and methods are equally applicable to deposition and cleaning processes that may occur in the described chambers, as well as other etching techniques and other etching that may be performed on a variety of exposed materials that may remain or substantially remain. Therefore, this technique should not be considered limited to use in the illustrated etching processes or chambers. Furthermore, although the illustrated chambers are described to provide the basis for this technique, it should be understood that this technique can be applied to virtually any semiconductor processing chamber that may allow the aforementioned operations.

[0026] Figure 1 shows a top plan view of one embodiment of a processing system 100 for deposition, etching, baking, and curing chambers according to an embodiment. In this figure, a pair of front-opening unified chambers (FOUPs) 102 supply substrates of varying sizes, which are received by a robotic arm 104 and placed into a low-pressure holding area 106 before being placed into one of the substrate processing chambers 108a-f, which are arranged in series segments 109a-c. A second robotic arm 110 can be used to transport substrate wafers from the holding area 106 to the substrate processing chambers 108a-f and then back. Each substrate processing chamber 108a-f can be equipped to perform multiple substrate processing operations, including the dry etching process described herein, as well as cyclic layer deposition (CLD), atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), etching, pre-cleaning, degassing, orientation, and other substrate processes.

[0027] 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, such as 108c-d and 108e-f, can be used to deposit dielectric material on the substrate, while a third pair of processing chambers, such as 108a-b, can be used to etch the deposited dielectric material. In another configuration, all three pairs of chambers, such as 108a-f, can be configured to etch dielectric films on the substrate. Any one or more of the processes described can be performed in chambers separate from the manufacturing systems shown in the different embodiments. System 100 takes into account additional dielectric film deposition, etching, annealing, and curing chamber configurations.

[0028] Figure 2A shows a cross-sectional view of an example processing chamber system 200, which includes partitioned plasma generation zones within the processing chamber. During film etching, process gases, such as titanium nitride, tantalum nitride, tungsten, silicon, polycrystalline silicon, silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, etc., can flow into the first plasma zone 215 via gas inlet assembly 205. A remote plasma system (RPS) 201 may be selectively included in the system and can process the first gas, which then passes through gas inlet assembly 205. Inlet assembly 205 may include two or more different gas supply channels, wherein a second channel (not shown), if included, may bypass RPS 201.

[0029] According to the embodiment, a cooling plate 203, a panel 217, an ion suppressor 223, a nozzle 225, and a base 265 or substrate support are shown, on which a substrate 255 is placed, each of which may be included. The base 265 may have a heat exchange channel through which a heat exchange fluid flows to control the temperature of the substrate. The base is operable to heat and / or cool the substrate or wafer during processing operations. The wafer support pad of the base 265 may comprise aluminum, ceramic, or a combination thereof, and may be heated to relatively high temperatures, such as from up to or about 100°C to above or about 1100°C, using an embedded resistance heater element.

[0030] Panel 217 may be conical, conical, or other similar structures, narrow at the top and wide at the bottom. Panel 217 may also be flat as shown and include a plurality of through-holes for distributing process gases. Depending on the use of RPS 201, plasma-generating gases and / or plasma-excited substances may pass through the plurality of holes in panel 217, as shown in FIG. 2B, to deliver them more uniformly to the first plasma region 215.

[0031] An example configuration may include opening the gas inlet assembly 205 into the gas supply region 258, which is separated from the first plasma region 215 by the panel 217, allowing gas / material to flow into the first plasma region 215 through an opening in the panel 217. Structural and operational features may be selected 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. The conductive upper portion of the panel 217 or chamber and the nozzle 225 are shown with an insulating ring 220 located between these features, allowing alternating current to be applied relative to the nozzle 225 and / or the ion suppressor 223 located on the panel 217. The insulating ring 220 may be located between the panel 217 and the nozzle 225 and / or the ion suppressor 223, thereby forming capacitively coupled plasma (CCP) within the first plasma region. In addition, a baffle (not shown) may be provided in the first plasma zone 215, or coupled to the gas inlet assembly 205, to affect the flow of fluid into the zone via the gas inlet assembly 205.

[0032] The ion suppressor 223 may include a plate or other geometry that structurally defines a plurality of holes configured to suppress the migration of charged particles from the first plasma region 215, while allowing uncharged neutral or radical material to pass through the ion suppressor 223 into an activated gas delivery region located between the suppressor and the nozzle. In some embodiments, the ion suppressor 223 may comprise a perforated plate with various hole configurations. These uncharged materials may include highly reactive materials that are transported through the holes along with a less reactive carrier gas. As described above, the migration of charged material through the holes can be reduced, and in some cases even completely suppressed. Controlling the amount of charged material passing through the ion suppressor 223 facilitates enhanced control over the gas mixture in contact with the underlying wafer substrate, which in turn can improve control over the deposition and / or etching characteristics of the gas mixture. For example, adjusting the ion concentration in the gas mixture can significantly alter its etching selectivity. In alternative embodiments where deposition is performed, this may also alter the balance between shape and flowable deposition in the dielectric material.

[0033] The plurality of orifices in the ion suppressor 223 can be configured to control the passage of the activating gas, i.e., ions, free radicals, and / or neutral substances, through the ion suppressor 223. For example, the aspect ratio of the orifices, or the ratio of the orifice diameter to its length, and / or the geometry of the orifices can be controlled to reduce the flow rate of charged substances in the activating gas through the ion suppressor 223. The orifices in the ion suppressor 223 may include a tapered portion facing the plasma excitation region 215 and a cylindrical portion facing the nozzle 225. The cylindrical portion can be shaped and designed to control the flow rate of ionic substances through the nozzle 225. An adjustable electrical bias can also be applied to the ion suppressor 223 as an additional means of controlling the flow rate of ionic substances through the suppressor.

[0034] The ion suppressor 223 can reduce or eliminate charged matter from the plasma generation region to the substrate. Uncharged neutral and free radical matter can still pass through the openings in the ion suppressor and react with the substrate. It should be noted that in some embodiments, it may not be possible to completely eliminate charged matter in the reaction region around the substrate. In some cases, ionic matter reaches the substrate to perform etching and / or deposition processes. In these cases, the ion suppressor may help control the concentration of ionic matter in the reaction region to assist the process.

[0035] The combination of the nozzle 225 and the ion suppressor 223 allows the plasma 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 be transferred from the chamber plasma region 215 to the substrate processing region 233. In this way, the chamber configuration prevents the plasma from contacting the substrate 255 being etched. This is beneficial for protecting the various intricate structures and films patterned on the substrate, as these structures and films may be damaged, displaced, or otherwise deformed if they come into direct contact with the generated plasma. Furthermore, the etching rate of oxide materials may increase when the plasma is allowed to contact or approach the substrate level. Therefore, if the exposed material area is oxide, the material can be further protected by holding the plasma at the far end of the substrate.

[0036] The processing system may also include a power supply 240 electrically connected 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 zone 215 or processing region 233. The power supply may be configured to provide an adjustable amount of power to the chamber depending on the process being performed. This configuration allows for the use of adjustable plasma in the performed process. Unlike remote plasma units that typically only have an on / off function, adjustable plasma can be configured to provide a specific amount of power to the plasma zone 215. This, in turn, allows specific plasma characteristics to develop, thereby causing precursors to dissociate in a specific manner to enhance the etch profile produced by these precursors.

[0037] The plasma can be ignited in the chamber plasma region 215 above the nozzle 225 or in the substrate processing region 233 below the nozzle 225. The plasma can be present in the chamber plasma region 215 to generate free radical precursors from the inflow of, for example, fluorine-containing precursors or other precursors. During the deposition process, an AC voltage typically in the radio frequency (RF) range is applied between the conductive upper part of the processing chamber, such as panel 217, and the nozzle 225 and / or ion suppressor 223 to ignite the plasma in the chamber plasma region 215. The RF power supply can generate RF frequencies up to 13.56 MHz, but can also generate other frequencies alone or in combination with a 13.56 MHz frequency.

[0038] Figure 2B shows a detailed view 253 of the characteristics affecting the distribution of process gases through panel 217. As shown in Figures 2A and 2B, panel 217, cooling plate 203, and gas inlet assembly 205 intersect to define gas supply region 258, through which process gases can enter. These gases may fill gas supply region 258 and flow into first plasma region 215 via orifice 259 on panel 217. The orifice 259 is designed to guide flow to achieve substantially unidirectional flow, allowing process gases to flow into processing region 233, but may partially or completely prevent backflow into gas supply region 258 after passing through panel 217.

[0039] The gas distribution assembly for processing chamber portion 200, such as nozzle 225, may be referred to as a dual-channel nozzle (DCSH) and is further described in detail in the embodiment of FIG3. The dual-channel nozzle can provide an etching process that allows the etchant to be separated outside the processing region 233 before entering the processing region, so as to be performed under constraints of interaction with the chamber components and with each other.

[0040] The nozzle 225 may include an upper plate 214 and a lower plate 216. These plates may be connected to each other to define a volume 218 between the plates. The connection of the plates may provide a first fluid channel 219 penetrating the upper and lower plates, and a second fluid channel 221 penetrating the lower plate 216. The formed channels may be configured to provide fluid from the volume 218 into the lower plate 216 only via the second fluid channel 221, while the first fluid channel 219 may be fluidly isolated from the volume 218 and the second fluid channel 221 located between the plates. The volume 218 may be fluidly accessible from one side of the nozzle 225.

[0041] FIG3 is a bottom view of a nozzle 325 for a processing chamber according to an embodiment. Nozzle 325 may correspond to nozzle 225 shown in FIG2A. Through-hole 365 shows a view of a first fluid channel 219, which may have multiple shapes and configurations to control and influence the flow of precursors through nozzle 225. Orifice 375 shows a view of a second fluid channel 221, which may be substantially uniformly distributed on the nozzle surface, even between through-holes 365, and may contribute to more uniform mixing of precursors as they exit the nozzle than in other configurations.

[0042] The chambers discussed previously can be used to perform example methods including etching methods. Referring to Figure 4, an example operation method 400 according to an embodiment of the present technology is shown. Method 400 may include one or more operations prior to the initiation 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 a number of optional operations that may or may not be particularly relevant to some embodiments of the method according to the present technology. For example, the description of many operations is intended to provide a broader scope of execution processes but is not critical to the technology or may be performed by alternative methods that will be discussed further below. Method 400 may describe operations schematically shown in Figures 5A-5B, whose illustrations will be used to illustrate the operations of method 400. It should be understood that these illustrations show only partial schematics, and the substrate may contain any number of additional materials and features, having the various properties and aspects shown in the figures.

[0043] Method 400 may or may not involve optional operations to develop the semiconductor structure to a specific manufacturing operation. It should be understood that method 400 can be performed on any number of semiconductor structures or substrates 505, as shown in FIG. 5A, including example structures capable of metal removal operations. Example semiconductor structures may include trenches, vias, or other recessed features that may contain one or more exposed materials. Furthermore, example semiconductor structures may include logic or memory structures, such as 3D NAND or DRAM structures. For example, example substrate 505 may contain silicon or other semiconductor substrate materials, and one or more material layers formed on substrate 505. As shown in FIG. 5A, a first material 510 and a second material 515 may be formed on substrate 505. Both the first material 510 and the second material 515 may have exposed areas. Furthermore, a metal-containing material 520 may also be formed on substrate 505 and may also include exposed areas.

[0044] The first material 510 and the second material 515 may be or include low dielectric constant materials, such as silicon-containing materials (e.g., silicon, silicon- and oxygen-containing materials, silicon- and germanium-containing materials, silicon- and nitrogen-containing materials, etc.), oxides (e.g., hafnium- and oxygen-containing materials, aluminum- and oxygen-containing materials, etc.), hard masking materials (e.g., carbon hard masking materials), or any other material that may be present on the metal-containing substrate. For example, in one exemplary embodiment, the first material 510 may be a silicon- and oxygen-containing material, such as SiO2, and the second material 515 may be a hafnium- and oxygen-containing material, such as HfO. The metal-containing material may be or include a metal, but may further include oxygen, nitrogen, or both. In some embodiments, the metal may be tungsten, molybdenum, niobium, titanium, or any other metal. Other metal-containing materials may include, for example, tungsten- and oxygen-containing materials, tungsten- and nitrogen-containing materials, molybdenum- and oxygen-containing materials, molybdenum- and nitrogen-containing materials, niobium- and oxygen-containing materials, niobium- and nitrogen-containing materials, titanium- and oxygen-containing materials, or titanium- and nitrogen-containing materials. In one example embodiment, the metallic material may be tungsten (W), molybdenum (Mo), or a material containing titanium and nitrogen, such as TiN.

[0045] It should be understood that the above structures are not intended to be limiting, and any other various semiconductor structures containing metallic materials are also included. Other example structures may include two-dimensional and three-dimensional structures common in semiconductor manufacturing, in which the metallic material will be removed relative to one or more other materials, as this technique can selectively remove the metallic material relative to other exposed materials (e.g., silicon-containing materials, other metallic materials, oxides and nitrides), as well as any other materials discussed elsewhere. Furthermore, while high aspect ratio structures may benefit from this technique, it is equally applicable to lower aspect ratios and any other structures.

[0046] For example, the material layers according to the present technology may have any aspect ratio characteristic, or height-to-width ratio of the structure, although in some embodiments these materials may have a large aspect ratio that may not allow for adequate etching using conventional techniques or methods. For example, in some embodiments, the aspect ratio of any layer in the example structure may be greater than or about 2:1, greater than or about 3:1, greater than or about 4:1, greater than or about 5:1, 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. Furthermore, each layer is characterized by a reduced width or thickness, which may be 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 5 nm, less than or about 1 nm, or even smaller, including any fraction of the above figures, such as 20.5 nm, 1.5 nm, etc. This combination of high aspect ratio and minimum thickness can hinder many conventional etching operations or require significantly longer etching times to remove a layer of material along a vertical or horizontal distance via a limited width. Additionally, conventional techniques may also damage or remove other exposed layers.

[0047] In embodiments, method 400 can be performed to remove exposed metallic material. For example, in embodiments of the present technology, any number of metallic materials, materials containing metal and nitrogen, or materials containing metal and oxygen can be removed, and this can be performed in any number of structures. These methods may include specific operations for removing metallic material, and may also include one or more optional operations for preparing or treating the metallic material. For example, the exemplary substrate structure may have residues from previous treatments on the film to be removed. For instance, residual photoresist or byproducts from previous treatments may remain on the metallic material. These materials may hinder access to the metallic material, or may interact with the etchant in a different way than a clean metallic surface, which may hinder one or more aspects of etching. Therefore, in some embodiments, optional pretreatment of the metallic film or material may be performed in optional operation 405. Exemplary pretreatment operations may include heat treatment, wet treatment, or plasma treatment, and may be performed, for example, in chamber 200, or in any number of chambers included in the system 100 described above.

[0048] In an example plasma pretreatment, a distal or local plasma can be developed from a precursor to interact with the residue in one or more ways. For example, using a chamber as described above, such as chamber 200, a distal 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 flow into a distal plasma region or processing area, where the plasma may be ignited. The plasma effluent can flow toward a substrate and may contact the residual material. The plasma process can be physical or chemical, depending on the material to be removed, to expose the metallic material. For example, the plasma effluent can flow to contact and physically remove the residue, such as via a sputtering operation, or the precursor can flow in to interact with the residue, generating volatile byproducts that can be removed from the chamber.

[0049] Example precursors used in the pretreatment may be or include hydrogen, hydrocarbons, water vapor, alcohols, hydrogen peroxide, or other materials that may contain hydrogen, as will be understood by those skilled in the art. Example oxygen-containing precursors may include molecular oxygen, ozone, nitrous oxide, nitrogen dioxide, or other oxygen-containing materials. Nitrogen may also be used, or a combination of precursors containing one or more of hydrogen, oxygen, and / or nitrogen may be used to remove specific residues. Once the residues or byproducts are removed, a clean metal-containing surface can be exposed for etching.

[0050] In operation 410 of method 400, an etchant precursor and an oxygen-containing precursor may be provided to a processing region of the semiconductor processing chamber. These precursors may flow via a distal plasma region of the processing chamber, such as region 215 described above, although in some embodiments, method 400 may not utilize plasma effluent during the etching operation. For example, method 400 may flow the etchant precursor and oxygen-containing precursor to substrate 505 without exposing the precursors to plasma, and may remove the metal-containing material 520 without generating plasma effluent. However, in some embodiments, the etchant precursor and oxygen-containing precursor may be plasma-enhanced, which may occur in the distal plasma region to protect the material on substrate 505 from contact with the plasma effluent. Plasma may also be locally formed if there is no concern about the material on the substrate contacting the plasma effluent.

[0051] In operation 415, method 400 may include contacting substrate 505 with an etchant precursor and an oxygen-containing precursor. The oxygen-containing precursor may contact substrate 505, including exposed metal-containing material 520, and may generate an oxidized metal-containing material that may remain on substrate 505. The etchant precursor may provide one or more etch atoms, such as halogen atoms, while accepting one or more oxygen atoms in some embodiments, resulting in the etching or removal of the oxidized metal-containing material. Thus, as shown in FIG5B, method 400 may include removing at least a portion of the metal-containing material 520 in operation 420. This removal may be performed relative to another material, such as a first material 510 and / or a second material 515.

[0052] As described above, this technology can be performed without plasma development during etching operations 410-415. Plasma-free removal can be achieved by utilizing specific precursors and performing etching under certain process conditions, and the removal can also be dry etching. Therefore, the techniques according to various aspects of this technology can be used to remove metallic material 515 from narrow features, high aspect ratio features, and thin dimensions, which may otherwise be unsuitable for wet etching. Optional operations can be performed to clean residues from the substrate or chamber, and post-processing can be included in optional operation 425. Post-processing can include operations similar to pre-processing and can include any precursors or operations discussed above for pre-processing. In some embodiments, post-processing can remove residual etchant, such as chlorine, from the substrate or chamber. It should be understood that although pre-processing or post-processing operations may include plasma generation and plasma effluent delivery to the substrate, plasma may not be formed during etching operations 410-420. For example, in some embodiments, no plasma may be generated when etchant precursors or precursors are delivered to the processing chamber.

[0053] The etchant precursor provided in operation 410 may include a halogen-containing precursor, and in some embodiments may include one or more of bromine, chlorine, or fluorine. A specific precursor may be based on the bonding or stability of the precursor. Exemplary etchant precursors may include boron trichloride (BCl3), as well as other halogen-containing precursors such as bromine-containing precursors, chlorine-containing precursors, or fluorine-containing precursors. Other halogen-containing precursors may include hydrobromic acid (HBr), thionyl bromide (SOBr2), thionyl bromide (SO2Br2), trichlorobromomethane (CCl3Br), diatomic chlorine (Cl2), hydrogen chloride (HCl), carbon tetrachloride (CCl4), phosphorus pentachloride (PCl5), thionyl chloride (SOCl2), thionyl chloride (SO2Cl2), diatomic fluorine (F2), nitrogen trifluoride (NF3), sulfur hexafluoride (SF6), tungsten hexafluoride (WF6), or any other halogen-containing material used or useful in semiconductor processing.

[0054] The oxygen-containing precursor provided in operation 410 can be any oxygen-containing material used or useful in semiconductor processing. For example, the oxygen-containing precursor can be or includes atomic oxygen (O), molecular oxygen (O2), ozone (O3), nitrogen dioxide (NO2), nitrous oxide (N2O), water or steam (H2O) or hydrogen peroxide (H2O2).

[0055] The etchant precursor and / or oxygen-containing precursor may also be provided with any number of carrier gases, which may include nitrogen, helium, argon or other noble gases, inert gases or useful precursors. These carrier gases can be used to dilute the etchant precursor, which may control the etching rate and help distribute the etchant precursor and / or control the pressure.

[0056] The flow rate of the etchant precursor can be adjusted, including in situ, to control the etching process. For example, the flow rate of the etchant precursor can be reduced, maintained, or increased during a removal operation. By increasing the flow rate of the etchant precursor, the etching rate can be increased to a saturation point. In any operation of method 400, the flow rate of the etchant precursor can be between about 5 sccm and about 1,000 sccm. Furthermore, the flow rate of the etchant precursor can be maintained below or about 900 sccm, below or about 800 sccm, below or about 700 sccm, below or about 600 sccm, below or about 500 sccm, or lower. However, in order to maintain a certain amount of etchant precursor in the processing area to accelerate the desired etching, the flow rate of the etchant precursor can be greater than or about 250 sccm, greater than or about 500 sccm, greater than or about 600 sccm, greater than or about 700 sccm, greater than or about 800 sccm, or higher. The flow rate of the etchant precursor can also be between any of the above flow rates, or within a smaller range encompassed by these figures.

[0057] Furthermore, the flow rate ratio of the oxygen-containing precursor to the etchant precursor may be greater than or about 2:1, greater than or about 2.2:1, greater than or about 2.4:1, greater than or about 2.6:1, greater than or about 2.8:1, greater than or about 3:1, or more. As previously mentioned, the oxygen-containing precursor may oxidize the metal-containing material 520, which can then be etched using the etchant precursor. Therefore, sufficient oxygen-containing material is required to ensure the oxidation of the metal-containing material 520. Some metal-containing materials 520 considered in the present art may be difficult to oxidize and may require a large amount of oxygen. Therefore, the flow rate of the oxygen-containing precursor may be greater than or about 1,000 sccm, greater than or about 1,200 sccm, greater than or about 1,400 sccm, greater than or about 1,600 sccm, greater than or about 1,800 sccm, greater than or about 2,000 sccm, greater than or about 2,200 sccm, greater than or about 2,400 sccm, or more.

[0058] Processing conditions may influence and promote etching according to the present technology. Because the etching reaction may be based on halogens thermally dissociated from the etchant precursor, temperature may be somewhat dependent on specific halogens and / or other atoms in the etchant precursor to initiate dissociation. For example, etching may begin or increase when the temperature rises above or to about 250°C, which may indicate that the dissociation of the precursor and / or reaction with the metal-containing material is activated. As the temperature continues to rise, dissociation may be further promoted, and the reaction with the metal-containing material may also be promoted. Therefore, higher temperatures may increase the etching rate of the metal-containing material, but may also reduce selectivity, as other materials may begin etching at higher rates.

[0059] In some embodiments, the method can be performed on a substrate that may have multiple generated features, which may generate a thermal budget. Therefore, in some embodiments of the present technology, the etching method can be performed at a temperature of the substrate, base and / or chamber below or about 650°C, and can be performed at temperatures below or about 600°C, below or about 575°C, below or about 550°C, below or about 525°C, below or about 500°C, below or about 490°C, below or about 480°C, below or about 470°C, below or about 460°C, below or about 450°C, below or about 440°C, below or about 430°C, below or about 420°C, below or about 410°C, below or about 400°C, below or about 380°C, below or about 360°C, below or about 340°C, below or about 320°C, below or about 300°C or lower. The temperature can also be maintained at any temperature within these ranges, or within a smaller range covered by these ranges, or between these ranges. Furthermore, as previously discussed, while higher temperatures may increase the etching rate of the metallic material 520, selectivity may be affected. Therefore, in some embodiments, the method can be carried out at temperatures above or about 250°C, and can be carried out at temperatures above or about 275°C, above or about 300°C, above or about 310°C, above or about 320°C, above or about 330°C, above or about 340°C, above or about 350°C, above or about 360°C, above or about 370°C, above or about 380°C, above or about 390°C, above or about 400°C, or higher.

[0060] The pressure within the chamber may also affect the operation performed and the dissociation temperature of the etchant precursor. Therefore, in some embodiments, the pressure may be maintained at greater than or about 0.5 Torr, greater than or about 1 Torr, greater than or about 2 Torr, greater than or about 3 Torr, greater than or about 4 Torr, greater than or about 5 Torr, greater than or about 6 Torr, greater than or about 7 Torr, greater than or about 8 Torr, greater than or about 9 Torr, greater than or about 10 Torr, greater than or about 15 Torr, greater than or about 20 Torr, greater than or about 25 Torr, greater than or about 30 Torr, greater than or about 40 Torr, greater than or about 50 Torr, greater than or about 60 Torr or higher. Furthermore, the pressure can be maintained below or about 50 Torr, below or about 40 Torr, below or about 30 Torr, below or about 25 Torr, below or about 20 Torr, below or about 15 Torr, below or about 10 Torr, below or about 9 Torr, below or about 8 Torr, below or about 7 Torr, below or about 6 Torr, below or about 5 Torr, below or about 4 Torr, below or about 3 Torr, below or about 2 Torr, below or about 1 Torr, below or about 0.1 Torr, or lower. The pressure can also be maintained at any pressure within these ranges, or within a smaller range encompassed by these ranges, or in between these ranges. In some embodiments, the amount of etching may be promoted and initiated with increasing pressure. Furthermore, as the pressure continues to increase, etching may improve to a certain extent, then begin to decrease, and eventually stop as the pressure continues to increase.

[0061] Without being limited to any particular theory, the pressure within the chamber may affect the processing of the aforementioned precursors. At low pressures, flow on the substrate may decrease, and dissociation may decrease accordingly. As pressure increases, the interaction between the etchant precursors and the substrate may increase, which may improve the reaction and etching rates. However, with continued pressure increases, the recombination of dissociated etchant precursor atoms may increase due to the relative stability of molecules. Consequently, these precursors may be effectively drawn out of the chamber without reacting with the substrate. Furthermore, with continued pressure increases, interaction with metal-containing materials may be suppressed, or byproducts containing metals and halogens may be reintroduced into the metal-containing material being etched, further limiting its removal. Therefore, in some embodiments, the pressure within the processing chamber may be maintained in the range of less than or about 100 Torr.

[0062] In some embodiments, the etching rate of the metal-containing material 520 may be greater than or about 5 Å per minute, greater than or about 10 Å per minute, greater than or about 25 Å per minute, greater than or about 50 Å per minute, greater than or about 70 Å per minute, greater than or about 100 Å per minute, or more. As previously mentioned, higher temperatures and certain pressures may increase the etching rate of the metal-containing material 520. Furthermore, the etching rate of metals may be faster than that of transition metal oxides or transition metal nitrides. Therefore, depending on the metal-containing material 520 to be etched, the etching rate can be maintained at any etching rate within these ranges, or within a smaller range covered by these ranges, or at any value between these ranges.

[0063] By performing the operations according to embodiments of the present invention, the metallic material 520 can be selectively etched relative to the second material, including other oxides or nitrides, or any of the previously mentioned materials related to the first material 510 and the second material 515. For example, the present invention can etch the metallic material 520 relative to the second material with a selectivity greater than or about 2:1, greater than or about 3:1, greater than or about 4:1, greater than or about 5:1, greater than or about 6:1, greater than or about 7:1, greater than or about 8:1, greater than or about 9:1, greater than or about 10:1, greater than or about 15:1, greater than or about 20:1, greater than or about 25:1, greater than or about 30:1, greater than or about 35:1, greater than or about 40:1, greater than or about 45:1, greater than or about 50:1 or higher. For example, etching performed according to certain embodiments of the present technology can etch the metallic material 520 while substantially retaining the second material (e.g., silicon oxide or other materials, such as silicon, aluminum or hafnium nitrides or oxides, or materials such as polycrystalline silicon).

[0064] The selectivity may be based on the precursor used and its ability to dissociate within a more controlled temperature range. Conventional plasma-enhanced etching may not achieve the etching selectivity achievable in this embodiment. Similarly, wet etchants may not be able to selectively etch at rates comparable to those in this embodiment, as wet etchants can readily remove materials with low dielectric constants. The previously discussed methods may allow for the removal of metallic materials relative to some other exposed materials. By utilizing the techniques described above, improved etching of metallic materials can be performed, potentially increasing selectivity compared to conventional techniques while achieving the desired etching rate to maintain throughput.

[0065] 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 certain details or with the addition of other details.

[0066] Having disclosed several embodiments, those skilled in the art will recognize that various modifications, alternative constructions, and equivalents can be used without departing from the spirit of these embodiments. Furthermore, to avoid unnecessarily obscuring the technology, many known processes and elements have not been described. Therefore, the above description should not be considered as limiting the scope of the technology. Additionally, methods or processes may be described as a sequence or steps, but it should be understood that these operations may be performed simultaneously or in a different order than those listed.

[0067] When a range of values ​​is provided, unless the context explicitly indicates otherwise, each intervening value between the upper and lower limits of the range, down to the smallest fraction of the lower limit unit, is also specifically disclosed. Any narrower range between any stated values ​​or unstated intervening values ​​within the range, as well as other stated or intervening values ​​within that range, are included. The upper and lower limits of these narrower ranges may be independently included or excluded from the range, and each range is also included in the technique if it includes any, both, or none of the narrower ranges, subject to any specific exclusions within the range. When the range includes one or two limits, the range excluding any or both including limits is also included.

[0068] In this specification and accompanying claims, the singular forms “a” and “an”, and “the”, include plural references unless the context clearly specifies otherwise. Thus, for example, a reference to “a precursor” includes a plurality of such precursors, and a reference to “the material” includes references to one or more materials and their equivalents (known to those skilled in the art), and so on.

[0069] Furthermore, when the words "including," "comprise," "contain," and "have" are used in this specification and the following claims, they are intended to specifically refer to the presence of the stated 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. [Simplified Explanation of the Diagram]

[0013] For a further understanding of the nature and advantages of the disclosed technology, please refer to the rest of the specification and the illustrations.

[0014] FIG1 shows a top plan view of an embodiment of an example processing system according to certain embodiments of the present technology.

[0015] FIG2A shows a schematic cross-sectional view of an example processing chamber according to certain embodiments of the present technology.

[0016] FIG2B shows a detailed view of a portion of the processing chamber shown in FIG2A according to certain embodiments of the present technology.

[0017] Figure 3 shows a bottom plan view of an example nozzle according to certain embodiments of the present technology.

[0018] Figure 4 shows an example operation of the method according to some embodiments of the present technology.

[0019] Figures 5A-5B show schematic cross-sectional views of the etched material according to certain embodiments of the present technology.

[0020] Several charts are presented in illustrative form. It should be understood that these charts are for illustrative purposes only and should not be considered to be displayed to scale unless specifically stated otherwise. Furthermore, as illustrative, these charts are intended to aid understanding and may not include all aspects or information compared to realistic representations, and may contain additional or exaggerated material for illustrative purposes.

[0021] In the accompanying illustrations, similar parts and / or features may have the same reference labels. Furthermore, various parts of the same type may be distinguished by the letters following the reference labels. When only the first reference label is used in the specification, the description applies to any similar parts having the same first reference label, regardless of the difference in letters. [Biomaterial Storage]

[0071] Domestic Deposit Information (Please note in order of deposit institution, date, and number) None

[0072] Overseas Deposit Information (Please note in the order of deposit country, institution, date, and number) None

Claims

1. A semiconductor processing method, comprising: An etchant precursor and an oxygen-containing precursor are provided to a processing region of a semiconductor processing chamber, wherein a substrate is disposed within the processing region, and wherein the substrate defines an exposed region of a metal-containing material and an exposed region of a second material; the substrate is brought into contact with the etchant precursor and the oxygen-containing precursor; and at least a portion of the metal-containing material is selectively removed relative to the second material.

2. The semiconductor processing method as claimed in claim 1, wherein the etchant precursor comprises a halogen-containing precursor.

3. The semiconductor processing method as claimed in claim 1, wherein the etchant precursor comprises a chlorine-containing precursor.

4. The semiconductor processing method as claimed in claim 3, wherein the chlorine-containing precursor comprises boron trichloride (BCl3).

5. The semiconductor processing method as claimed in claim 1, wherein the oxygen-containing precursor comprises diatomic oxygen (O2).

6. The semiconductor processing method as claimed in claim 1, wherein the metal-containing material includes tungsten, molybdenum, niobium, or titanium.

7. The semiconductor processing method as claimed in claim 6, wherein the metal-containing material further comprises oxygen, nitrogen, or both.

8. The semiconductor processing method as claimed in claim 1, wherein the process of removing the portion of the metal-containing material does not use plasma.

9. The semiconductor processing method as claimed in claim 1, wherein the removal of the portion of the metal-containing material is carried out at a temperature below or about 550°C.

10. The semiconductor processing method as claimed in claim 1, wherein the removal of the metal-containing material from the portion is carried out under a pressure of more than or about 0.5 Torr.

11. A semiconductor processing method, comprising: A chlorine-containing precursor and an oxygen-containing precursor are provided to a processing region of a semiconductor processing chamber, wherein a substrate is disposed within the processing region and the substrate defines an exposed region of a metal-containing material and an exposed region of a second material; the substrate is brought into contact with the chlorine-containing precursor and the oxygen-containing precursor; and at least a portion of the metal-containing material is selectively removed relative to the second material, wherein the removal of the portion of the metal-containing material is performed without plasma.

12. The semiconductor processing method of claim 11, wherein a flow rate ratio of the oxygen-containing precursor to the chlorine-containing precursor is greater than or about 2:

1.

13. The semiconductor processing method of claim 11, wherein the second material comprises hafnium oxide, aluminum oxide, silicon oxide, silicon nitride, silicon, silicon germanium, or a carbon hard mask.

14. The semiconductor processing method as described in claim 11, further comprising: An inert precursor is provided together with the chlorine-containing precursor and the oxygen-containing precursor.

15. The semiconductor processing method as claimed in claim 11, wherein the removal of the portion of the metal-containing material is carried out at a temperature above or about 250°C.

16. The semiconductor processing method as claimed in claim 11, wherein the removal of the portion of the metal-containing material is carried out under a pressure of more than or about 30 Torr.

17. A semiconductor processing method, comprising: An etchant precursor and an oxygen-containing precursor are provided to a processing region of a semiconductor processing chamber, wherein a substrate is disposed within the processing region, wherein the substrate defines an exposed region of a metal-containing material and an exposed region of a second material, and wherein a flow rate of the oxygen-containing precursor is greater than a flow rate of the etchant precursor; the substrate is brought into contact with the etchant precursor and the oxygen-containing precursor; and at least a portion of the metal-containing material is selectively removed relative to the second material at a ratio greater than or about 10:

1.

18. The semiconductor processing method of claim 17, wherein the etchant precursor comprises boron trichloride (BCl3) or tungsten hexafluoride (WF6), and the oxygen-containing precursor comprises diatomic oxygen (O2).

19. The semiconductor processing method as claimed in claim 17, wherein the metal-containing material comprises tungsten, molybdenum, niobium, or titanium.

20. The semiconductor processing method as claimed in claim 17, wherein the removal of the metal-containing material from the portion is performed without plasma.

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