Improved germanium etching system and method

Abstract

An exemplary method for etching a germanium-containing material may include forming a plasma of a fluorine-containing precursor in a remote plasma region of a semiconductor processing chamber. The method may include flowing an effluent of a fluorine-containing precursor through an aperture defined in a chamber component. The pores may be coated with a catalytic material. The method may include using a catalytic material to reduce the concentration of fluorine radicals in the plasma effluent. The method may also include delivering the plasma effluent to a processing region of the semiconductor processing chamber. A substrate having an exposed region of germanium-containing material may be housed within the processing region. The method may also include etching the germanium-containing material.

Description

This application is a divisional application with application date of August 3, 2018, application number 201810877233.8, and titled “Improved Germanium Etching System and Method”. Technical Field

[0001] The present technology relates to semiconductor processes and equipment. More particularly, the present technology relates to etching SiGe during semiconductor processing using catalytic conversion. Background Art

[0002] Integrated circuits are made possible by processes that produce layers of material with complex patterns on a substrate surface. Producing patterned material on a substrate requires a controlled method for removing exposed material. Chemical etching is used for a variety of purposes, including transferring a pattern in a photoresist to an underlying layer, thinning a layer, or thinning the lateral dimensions of a feature already present on a surface. Generally, it is desirable to have an etching process that etches one material faster than another material to facilitate, for example, a pattern transfer process. Such etching processes are referred to as being selective to the first material. Due to the diversity of materials, circuits, and processes, etching processes have been developed to have selectivity for a variety of materials.

[0003] The etching process may be referred to as wet etching or dry etching based on the materials used in the process. Wet HF etching preferably removes silicon oxide on top of other dielectrics and materials. However, wet processes may have difficulty penetrating some restricted grooves and may sometimes also deform the remaining materials. Dry etching generated in a local plasma formed in the substrate processing area can penetrate more restricted grooves and deform the delicate remaining structures less. However, local plasmas may damage the substrate by arcing when they discharge.

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

[0005] An exemplary method for etching a germanium-containing material may include forming a plasma containing a fluorine precursor in a remote plasma region of a semiconductor processing chamber. The method may include flowing a plasma effluent of the fluorine-containing precursor through a hole defined in a chamber component. The hole may be coated with a catalytic material. The method may include reducing the concentration of fluorine radicals in the plasma effluent with the catalytic material. The method may also include delivering the plasma effluent to a processing region of the semiconductor processing chamber. A substrate having an exposed region of the germanium-containing material may be accommodated in the processing region. The method may also include etching the germanium-containing material.

[0006] In some embodiments, the catalytic material may be or include one or more materials including an element selected from the group consisting of nickel, cobalt, vanadium, niobium, tantalum, chromium, manganese, rhenium, iron, ruthenium, osmium, palladium, platinum, rhodium, and iridium. This may include an oxide of any of the materials mentioned. The chamber components may be maintained at a temperature greater than about 70° C. The substrate may be maintained at a temperature less than about 30° C. The germanium-containing material may be or include SiGe. The germanium-containing material may be a first germanium-containing material, and the first germanium-containing material may be etched relative to silicon or a second germanium-containing material. The second germanium-containing material may be characterized by a lower germanium concentration than the first germanium-containing material. The etching may have a selectivity toward the first germanium-containing material greater than or about 300:1 relative to silicon or the second germanium-containing material. The pressure within the processing chamber may be maintained above about 2 Torr. The chamber component may be a showerhead or an ion suppressor.

[0007] The present technology also encompasses another method of etching a germanium-containing material. The method may include forming a plasma containing a fluorine precursor in a remote plasma region of a semiconductor processing chamber. The method may include flowing a plasma effluent of the fluorine-containing precursor through a chamber component containing a catalytic material. The method may include catalytically converting at least a portion of fluorine radicals in the plasma effluent by the catalytic material. The method may include delivering the plasma effluent to a processing region of the semiconductor processing chamber. A substrate having an exposed region containing a germanium-containing material may be accommodated in the processing region. The method may also include etching the germanium-containing material.

[0008] In some embodiments, converting fluorine radicals may include forming a material including at least two fluorine atoms from fluorine radicals on a catalytic material. Chamber components may include one or more of a remote plasma unit delivery tube, a baffle, a panel, an ion suppressor, or a showerhead. The catalytic material may be or include one or more materials including an element selected from the group consisting of nickel, cobalt, vanadium, niobium, tantalum, chromium, manganese, rhenium, iron, ruthenium, osmium, palladium, platinum, rhodium, and iridium, and oxides of any of these materials. Chamber components may be maintained at a temperature greater than about 70° C. The substrate may be maintained at a temperature less than about 30° C. The pressure within the processing chamber may be maintained between about 1 Torr and about 30 Torr.

[0009] The present technology may also include other methods of etching germanium-containing materials. The method may include forming a plasma containing a fluorine precursor in a remote plasma region of a semiconductor processing chamber. The method may include: flowing a plasma effluent of a fluorine-containing precursor through a hole defined in a chamber component. The hole may be coated with a catalytic material, and the chamber component may be maintained at a temperature between about 70°C and about 150°C. The method may include reducing the concentration of fluorine radicals in the plasma effluent with a catalytic material. The method may include delivering the plasma effluent to a processing region of a semiconductor processing chamber. A substrate having an exposed region containing germanium material may be accommodated in the processing region. The substrate may be maintained at a temperature below about 30°C. The method may also include etching the germanium-containing material.

[0010] In some embodiments, the catalytic material may include one or more materials including an element selected from the group consisting of nickel, cobalt, vanadium, niobium, tantalum, chromium, manganese, rhenium, iron, ruthenium, osmium, palladium, platinum, rhodium and iridium, and oxides of these materials. The pressure within the processing chamber may be maintained between about 1 Torr and about 30 Torr. The chamber component may be or include a showerhead or an ion suppressor.

[0011] This technique can provide many benefits over conventional systems and techniques. For example, the process can allow for high etch selectivity of germanium-containing materials relative to other exposed materials on the substrate. In addition, plasma operations can provide more tuning capabilities than thermal-based etching operations. These and other embodiments and their many advantages and features are described in more detail in conjunction with the following description and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0013] Figure 1 A top plan view of one embodiment of an exemplary processing system in accordance with embodiments of the present technology is shown.

[0014] Figure 2A A schematic cross-sectional view of an exemplary processing chamber in accordance with an embodiment of the present technology is shown.

[0015] Figure 2B The embodiment according to the present technology is shown Figure 2A Detailed view of a portion of a processing chamber shown in FIG.

[0016] Figure 3 A bottom plan view of an exemplary showerhead is shown in accordance with an embodiment of the present technology.

[0017] Figure 4Exemplary operations in a method according to an embodiment of the present technology are shown.

[0018] Several of the drawings are included as schematic diagrams. It will be understood that the drawings are for illustrative purposes and are not considered to be drawn to scale unless expressly indicated as being drawn to scale. In addition, the drawings provided as schematic diagrams are used to aid understanding and may not include all aspects or information compared to actual representations and may include exaggerated material for illustrative purposes.

[0019] In the accompanying drawings, similar components and / or features may have the same reference numeral. In addition, various components of the same type may be distinguished by adding a letter after the reference numeral to distinguish the similar components. If only the first reference numeral is used in this specification, the description applies to any of the similar components having the same first reference numeral, regardless of the letter. DETAILED DESCRIPTION

[0020] Since many new semiconductor structures utilize alternative materials, germanium-containing materials (such as germanium and silicon germanium or SiGe) may be used more and more. Fluorine-containing precursors can be used to etch germanium-containing materials in some techniques, however, many other exposed materials on the substrate may be susceptible to etching. For example, depending on the process conditions and other precursors utilized in the process, fluorine materials (such as fluorine radicals in plasma effluents) can etch silicon, silicon nitride or silicon oxide. Conventional methods may have accepted this drawback and adjusted certain process conditions, structural features and etchant chemicals to accommodate this limitation. The present technology can overcome these problems by producing an in-situ etchant specifically tuned to reduce reactivity with silicon, nitride and other semiconductor materials. This can significantly increase the etching rate compared to conventional techniques.

[0021] While the remainder of the disclosure will routinely identify a particular etching process utilizing the disclosed techniques, it will be readily appreciated that the systems and methods are equally applicable to deposition and cleaning processes that may occur in the described chambers. Thus, the described techniques should not be considered as being so limited to use with only etching processes or chambers. Furthermore, while an exemplary chamber is described as providing the basis for the present techniques, it will be appreciated that the present techniques may be applied to virtually any semiconductor processing chamber that may allow for the described single chamber operation.

[0022] Figure 1A top plan view of one embodiment of a processing system 100 having a deposition chamber, an etch chamber, a bake chamber, and a cure chamber according to an embodiment is shown. In the figure, a pair of front opening unified wafer boxes (FOUPs) 102 supply substrates of various 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 positioned in the tandem sections 109a-c. A second robotic arm 110 can be used to transfer substrate wafers from the holding area 106 to the substrate processing chambers 108a-f and from the substrate processing chambers 108a-f back to the holding area 106. Each substrate processing chamber 108a-f can be equipped to perform a number of substrate processing operations, including the dry etching processes described herein in addition to 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.

[0023] The substrate processing chambers 108a-f may include one or more system components for depositing, annealing, curing, and / or etching dielectric or metal films on substrate wafers. In one configuration, two pairs of processing chambers (e.g., 108c-d and 108e-f) may be used to deposit materials on substrates, and a third pair of processing chambers (e.g., 108a-b) may be used to etch the deposited materials. In another configuration, all three pairs of chambers (e.g., 108a-f) may be configured to etch dielectric or metal films on substrates. Any one or more of the processes described may be performed in a chamber separate from the manufacturing system shown in different embodiments. It will be appreciated that the system 100 also contemplates additional configurations of deposition chambers, etching chambers, annealing chambers, and curing chambers for dielectric films.

[0024] Figure 2A A cross-sectional view of an exemplary processing chamber system 200 having a separate plasma generation region within the processing chamber is shown. During etching of films, such as titanium nitride, tantalum nitride, tungsten, copper, cobalt, silicon, polysilicon, silicon oxide, silicon nitride, silicon oxynitride, silicon oxycarbide, etc., a process gas may flow through a gas inlet assembly 205 into a first plasma region 215. A remote plasma system (RPS) 201 may optionally be included in the system and may process a first gas, which then travels through the gas inlet assembly 205. The inlet assembly 205 may include two or more different gas supply channels, wherein a second channel (not shown) may bypass the RPS 201 if included.

[0025] Blocking plate 203, face plate 217, ion suppressor 223, showerhead 225, and substrate support pedestal 255 having substrate 265 disposed thereon are shown and may each include depending on the embodiment. The pedestal 265 may have heat exchange channels through which a heat exchange fluid flows to control substrate temperature, and the pedestal may be operated to heat and / or cool the substrate or wafer during processing operations. The wafer support plate of the pedestal 265, which may include aluminum, ceramic, or a combination thereof, may also be resistively heated using embedded resistive heater elements to achieve relatively high temperatures, such as from up to or about 100° C. to above or about 600° C.

[0026] The panel 217 may be pyramidal, conical, or another similar structure with a narrow top that expands to a wide bottom. As shown, the panel 217 may alternatively be flat and include a plurality of channels for distributing process gases. Depending on the use of the RPS 201, the plasma generating gas and / or plasma excited species may pass through a plurality of holes in the panel 217, such as Figure 2B As shown, so as to be more uniformly delivered into the first plasma region 215.

[0027] An exemplary configuration may include opening the gas inlet assembly 205 into a gas supply region 258 separated from the first plasma region 215 by a faceplate 217, such that the gas / species flows into the first plasma region 215 through holes in the faceplate 217. Structural and operational features may be selected to prevent plasma from substantially flowing back from the first plasma region 215 into the supply region 258, the gas inlet assembly 205, and the fluid supply system 210. The faceplate 217 (or conductive top of the chamber) and the showerhead 225 are shown with an insulating ring 220 positioned between the features, which allows an AC potential to be applied to the faceplate 217 relative to the showerhead 225 and / or the ion suppressor 223. The insulating ring 220 may be positioned between the faceplate 217 and the showerhead 225 and / or the ion suppressor 223, thereby enabling a capacitively coupled plasma (CCP) to form in the first plasma region. Baffles (not shown) may additionally be located in the first plasma region 215 or otherwise coupled to the gas inlet assembly 205 to affect the flow of fluid through the gas inlet assembly 205 and into the region.

[0028] The ion suppressor 223 may include a plate or other geometric structure that defines a plurality of holes throughout the structure that are configured to suppress the migration of ionic charged species out of the first plasma region 215 while allowing uncharged neutral or radical species to pass through the ion suppressor 223 into the activated gas delivery region between the suppressor and the showerhead. In an embodiment, the ion suppressor 223 may include a porous plate with a variety of hole configurations. These uncharged species may include highly reactive species that are transported through the holes along with a less reactive carrier gas. As described above, the migration of ionic species through the holes may be reduced and, in some cases, completely suppressed. Controlling the amount of ionic species that pass through the ion suppressor 223 may advantageously provide increased control over the gas mixture in contact with the underlying wafer substrate, which in turn may increase control over the deposition and / or etching characteristics of the gas mixture. For example, adjustment of the ion concentration of the gas mixture may significantly change its etching selectivity, e.g., SiNx:SiOx etching ratio, Si:SiOx etching ratio, etc. This may also shift the balance of conformal to flowable deposition of dielectric materials in alternative embodiments of performing the deposition.

[0029] The plurality of holes in the ion suppressor 223 may be configured to control the flow of activated gas (i.e., ionic species, radical species, and / or neutral species) through the ion suppressor 223. For example, the hole aspect ratio, or the ratio of hole diameter to length, and / or the geometry of the holes may be controlled to reduce the flow of ionic charged species in the activated gas through the ion suppressor 223. The holes in the ion suppressor 223 may include a conical portion facing the plasma excitation region 215 and a cylindrical portion facing the showerhead 225. The shape and size of the cylindrical portion may be set to control the flow of ionic species to the showerhead 225. An adjustable electrical bias may also be applied to the ion suppressor 223 as an additional means of controlling the flow of ionic species through the suppressor.

[0030] The ion suppressor 223 can be used to reduce or eliminate the amount of charged species that travel from the plasma generation region to the substrate. Uncharged neutral and free radical species can still pass through the openings in the ion suppressor to react with the substrate. It should be noted that in embodiments, complete elimination of charged species in the reaction region around the substrate may not be performed. In some cases, the charged species are intended to reach the substrate to perform an etching process and / or a deposition process. In these cases, the ion suppressor can help control the concentration of the charged species in the reaction region to a level that is conducive to the process.

[0031] The showerhead 225 in combination with the ion suppressor 223 can allow the plasma present in the first plasma region 215 to avoid directly exciting the gases in the substrate processing region 233, while still allowing excited species to travel from the chamber plasma region 215 into the substrate processing region 233. In this way, the chamber can be configured to prevent the plasma from contacting the substrate 255 being etched. This can advantageously protect various complex structures and films patterned on the substrate, which may be damaged, misaligned, or warped if directly contacted by the generated plasma. In addition, the etch rate of oxide species may increase when the plasma is allowed to contact the substrate or approach the level of the substrate. Therefore, if the exposed material area is an oxide, then this material can be further protected by maintaining the plasma away from the substrate.

[0032] The processing system may further include a power supply 240 electrically coupled to the processing chamber to provide power to the faceplate 217, the ion suppressor 223, the showerhead 225, and / or the pedestal 265 to generate plasma in the first plasma region 215 or the 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. This configuration may allow a tunable plasma to be used in the process being performed. Unlike a remote plasma unit that typically has an on or off function, a tunable plasma may be configured to deliver a specific amount of power to the plasma region 215. This in turn may allow specific plasma characteristics to be formed so that precursors may be dissociated in a specific manner to enhance the etch profile produced by these precursors.

[0033] Plasma may be ignited in the chamber plasma region 215 above the showerhead 225 or in the substrate processing region 233 below the showerhead 225. Plasma may exist in the chamber plasma region 215 to generate radical precursors from, for example, an inflow of a fluorine-containing precursor or other precursor. An AC voltage, typically in the radio frequency (RF) range, may be applied between a conductive top portion of the processing chamber, such as a face plate 217, and the showerhead 225 and / or the ion suppressor 223 to ignite a plasma in the chamber plasma region 215 during deposition. The RF power source may generate a high RF frequency of 13.56 MHz, but other frequencies may also be generated alone or in combination with the 13.56 MHz frequency.

[0034] Figure 2B A detailed view 253 of features that affect the distribution of process gases through the panel 217 is shown. Figure 2A and 2BAs shown, the faceplate 217, the baffle plate 203, and the gas inlet assembly 205 intersect to define a gas supply region 258 into which the process gas can be delivered from the gas inlet assembly 205. The gas can fill the gas supply region 258 and flow into the first plasma region 215 through the holes 259 in the faceplate 217. The holes 259 can be configured to direct the flow in a substantially unidirectional manner such that the process gas can flow into the processing region 233, but can be partially or completely prevented from flowing back into the gas supply region 258 after passing over the faceplate 217.

[0035] The gas distribution assembly used in the processing chamber system 200, such as the showerhead 225, may be referred to as a dual channel showerhead (DCSH) and is further described in detail in Figure 3 In the embodiments described in . A dual channel showerhead may be used for the etching process, allowing the etchants to be separated outside the processing region 233 before being delivered into the processing region to provide limited interaction with chamber components and with each other.

[0036] The showerhead 225 may include an upper plate 214 and a lower plate 216. The plates may be coupled to one another to define a volume 218 between the plates. The coupling of the plates may be such as to 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 passages may be configured to provide fluid access from 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 plate and the second fluid passage 221. The volume 218 may be fluidly accessible through a side of the gas distribution assembly or showerhead 225.

[0037] Figure 3 FIG. 3 is a bottom view of a showerhead 325 for use with a processing chamber according to an embodiment. The showerhead 325 may correspond to Figure 2A . The through-holes 365 showing a view of the first fluid channel 219 can have a variety of shapes and configurations to control and influence the flow of precursors through the showerhead 225. The small holes 375 showing a view of the second fluid channel 221 can be substantially evenly distributed over the surface of the showerhead, even between the through-holes 365, and can help provide more uniform mixing of the precursors as they exit the showerhead compared to other configurations.

[0038] The chambers discussed previously can be used to perform exemplary methods including etching methods. Figure 4 , Figure 4Exemplary operations in a method 400 according to embodiments of the present technology are shown. Prior to the first operation of the method, the substrate may be processed in one or more ways before being placed in a processing region of a chamber in which the method 400 may be performed. For example, features may be generated and a germanium-containing material may be formed on the substrate. In some embodiments, a first germanium-containing material may be formed that is characterized by a first germanium concentration, and a second germanium-containing material may be formed that is characterized by a second germanium concentration. Additional materials that may be formed and / or exposed on the substrate may include silicon, nitride, or oxide materials.

[0039] The method 400 may include forming a plasma of a fluorine-containing precursor in a remote plasma region of a semiconductor processing chamber at operation 405. The remote plasma region may be a region adjacent to a processing region where a substrate may be housed, such as the region 215 discussed previously. The remote plasma region may also be a separate remote plasma unit fluidly coupled to the processing chamber, such as the RPS 201 described previously. The plasma may be a remote plasma in that it may not be formed at the wafer or substrate level, and in some embodiments, the processing region in which the substrate is housed may be maintained plasma-free during operation of the etching method 400. "Plasma-free" means that a wafer-level plasma may not be formed during operation, but some migrating elements from the remote plasma region may extend into the processing region.

[0040] In an embodiment, the fluorine-containing precursor may be nitrogen trifluoride. Other fluorine sources may be used to increase or replace nitrogen trifluoride. Generally, the fluorine-containing precursor may flow into the plasma region, and the fluorine-containing precursor may include one or more fluorine-containing materials, such as fluorocarbons, atomic fluorine, diatomic fluorine, halogen interfluorides (such as bromine trifluoride or chlorine trifluoride), nitrogen trifluoride, sulfur hexafluoride, or xenon difluoride. In some embodiments, the fluorine-containing precursor may be nitrogen trifluoride, which may produce excited neutral fluorine species with a longer life in the plasma effluent. One or more additional precursors may flow with the fluorine-containing precursor and may be used as a carrier gas or may be delivered to the processing chamber separately. Additional precursors may include argon, helium, neon, xenon, or some other materials configured to help dissociation, etchant formation, or flow characteristics of fluorine-containing materials. In an embodiment, the flow rate of the additional precursor may be twice, three times, four times, or five times greater than the flow rate of nitrogen trifluoride, which may improve the etching selectivity of silicon germanium.

[0041] Plasma effluent formed by the plasma may flow into or through the chamber and may be brought into contact with or through the catalytic material at operation 410. In an embodiment, the catalytic material may be included on one or more chamber components and may be positioned relative to the plasma formation. For example, the catalytic material may be associated with an ion suppressor or a nozzle (such as ion suppressor 223 and nozzle 225). The catalytic material may be coated on the component, incorporated as a plug-in, or the component may be at least partially formed of the catalytic material. As a non-limiting example, in some embodiments, the catalytic material may be coated on one or more surfaces of the component. For a nozzle or ion suppressor, the catalytic material may be coated on the upstream side of the component, or coated on the entire component.

[0042] The catalytic material may be formed specifically through the holes of the component. These holes can provide a high surface area, and the particles can collide or interact with the side walls of the hole multiple times before traveling through the component. This can provide ample opportunity for catalytic conversion to occur. In addition, other components of the processing chamber may be coated with or include a catalytic material. For example, when a plasma effluent is formed in an RPS unit, one or more components of the chamber may include a catalytic material. For example, the delivery tube of the inlet assembly 205 may be lined with a catalytic material. In addition, any surface including the side walls of the holes of the baffle 203, the face plate 217, the ion suppressor 223, or the showerhead 225 may be coated with or coupled to a catalytic material.

[0043] At operation 415, a catalytic conversion may occur to reduce the number or concentration of fluorine radicals in the plasma effluent. The catalytic material may help convert the fluorine atoms into an additional material including at least two fluorine atoms per molecule. For example, when nitrogen trifluoride is used as an exemplary fluorine-containing precursor, the plasma effluent may include a combination of materials including NF*, NF2*, and F*. The fluorine radicals may etch silicon and silicon nitride materials exposed on the substrate, which may reduce the selectivity of the germanium or SiGe etch. As the critical dimensions on ever-shrinking devices continue to decrease, a selectivity of 10, 50, or even 100 may not be sufficient to maintain other materials during germanium etching.

[0044] The catalytic material can help convert the fluorine radicals into alternative etchant materials, such as F2, N2F4, or other combinations with multiple bonded fluorine atoms or with reduced or no radical components. These etchants (such as F2) can preferentially etch germanium or silicon germanium relative to silicon, nitrides, oxides, and other silicon germanium (such as those with reduced germanium concentrations). Once the catalytic conversion or reduction of the fluorine radicals has occurred, the modified plasma effluent can be delivered to a processing area that can accommodate a substrate in operation 420. Subsequently, the germanium-containing material can be etched in operation 425. By substantially reducing the concentration of fluorine radical species, the present technology can produce an increased etching selectivity compared to conventional techniques. For example, the present technology can etch silicon germanium or germanium relative to silicon, silicon nitride, or silicon germanium having a lower germanium concentration with a selectivity of greater than or about 100:1, greater than or about 200:1, greater than or about 300:1, greater than or about 400:1, greater than or about 500:1, greater than or about 600:1, greater than or about 700:1, greater than or about 800:1, greater than or about 900:1, or up to or greater than 1000:1 in embodiments.

[0045] The present technology can etch a first silicon germanium relative to a second silicon germanium having a lower germanium concentration. Generally speaking, for all X>Y (down to Y being 0 (where the film contains silicon) and up to X being 1 (where the film contains germanium)), Si(1-X)GeX can be etched faster than Si(1-Y)GeY. Si(1-X)GeX can be etched at a first etch rate, while Si(1-Y)GeY can be etched at a second etch rate. According to an embodiment, the first etch rate can be greater than the second etch rate. In an embodiment, the first etch rate can exceed the second etch rate by 10 times, 20 times, 50 times, 100 times, 300 times, 500 times, or more, depending on the difference in germanium concentration between the two materials.

[0046] The catalytic material can be or include any number of materials known for providing a catalytic surface. For example, the catalytic material can be or include various concentrations of nickel, cobalt, vanadium, niobium, tantalum, chromium, manganese, rhenium, iron, ruthenium, osmium, palladium, platinum, rhodium, iridium, and oxides of any of these materials, or other known catalytic substances.

[0047] Temperature and pressure can affect the catalytic activity and selectivity of the present technology. For example, in order to ensure sufficient catalytic activity, in an embodiment, the temperature of the device on which the catalytic material is disposed can be greater than or about 50°C. Temperatures below about 50°C or more may not be sufficient to convert fluorine radicals, which can reduce or substantially reduce the selectivity of the etching process. In addition, the temperature can be greater than or about 60°C, greater than or about 65°C, greater than or about 70°C, greater than or about 75°C, greater than or about 80°C, greater than or about 85°C, greater than or about 90°C, greater than or about 95°C, greater than or about 100°C, greater than or about 105°C, greater than or about 110°C, greater than or about 115°C, greater than or about 120°C, greater than or about 125°C, greater than or about 130°C, greater than or about 135°C, greater than or about 140°C, greater than or about 145°C, greater than or equal to 150°C or higher.

[0048] The diatomic fluorine produced by the plasma technology of the present invention can advantageously etch germanium-containing materials. However, the diatomic fluorine may be prone to dissociation in the chamber environment, which can reduce the selectivity of the process. Therefore, in some embodiments, the temperature can be maintained below or about 200°C, below or about 190°C, below or about 180°C, below or about 170°C, below or about 160°C, below or about 150°C, below or about 140°C, below or about 130°C, below or about 120°C or lower to limit the dissociation of fluorine and maintain sufficient etching selectivity.

[0049] The substrate temperature may additionally contribute to the etch selectivity, and while an increased catalytic temperature may be beneficial to etchant production, such a temperature may reduce the selectivity of the process when the etchant is delivered to the substrate. Thus, during method 400, the substrate may be maintained at or below about 50°C in embodiments, and may be maintained at or below about 45°C, at or below about 40°C, at or below about 35°C, at or below about 30°C, at or below about 25°C, at or below about 20°C, at or below about 15°C, at or below about 10°C, at or below about 5°C, at or below about 0°C, at or below about -5°, or less in embodiments.

[0050] The pressure in the processing chamber may also contribute to the formation of the etchant and the selectivity of the operation. In some embodiments, the pressure may be greater than or about 1 Torr, and may be greater than or about 2 Torr, greater than or about 3 Torr, greater than or about 5 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 35 Torr, greater than or about 40 Torr, greater than or about 45 Torr, greater than or about 50 Torr, or higher. Higher pressure may contribute to the collision or interaction of plasma effluent species, and therefore in embodiments, the pressure in the chamber may be maintained to be greater than or about 2 Torr or about 3 Torr. However, when the partial pressure increases, the pressure may also contribute to the dissociation of diatomic fluorine, which may further increase the collision of the etchant species formed by the damage. As the etchant molecules dissociate, the selectivity is reduced due to the regeneration of the fluorine radical effluent. Thus, the pressure may be maintained below or at about 50 Torr, below or at about 40 Torr, below or at about 30 Torr, or below or at about 20 Torr to maintain the aforementioned selectivity.

[0051] By operating within the pressure and temperature ranges discussed, the present techniques can produce etchant species that preferentially remove germanium-containing materials. These operations can provide removal rates and selectivities for germanium-containing materials that exceed conventional techniques.

[0052] In the foregoing description, for the purpose of explanation, many details have been set forth in order to provide an understanding of various embodiments of the present technology. However, it is apparent to one skilled in the art that certain embodiments may be practiced without some of these details or with additional details.

[0053] Where several embodiments have been disclosed, those skilled in the art will recognize that various modifications, alternative configurations, and equivalents may be used without departing from the spirit of the embodiments. In addition, many well-known processes and elements have not been described in order to avoid unnecessarily obscuring the present technology. Therefore, the above description should not be considered to limit the scope of the present technology. In addition, methods or processes may be described as sequential or step-by-step, but it will be understood that the operations may be performed simultaneously or in an order different from the order listed.

[0054] Where a range of values ​​is provided, it will be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed, to the smallest fraction of the lower limit unit, unless otherwise clearly indicated in the context. Any narrower range between any stated value or unstated intermediate value in the stated range and any other stated value or intermediate value in the stated range is included. The upper and lower limits of those smaller ranges may be independently included or excluded from the range, and each range in which any limit, no limit, or two limits are included in the smaller range is also included in the present technology, depending on any specifically excluded limit in the stated range. Where the stated range includes one or two of these limits, the range excluding any one or two of those included limits is also included.

[0055] As used herein and in the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a precursor" includes a plurality of such precursors and reference to "a layer" includes reference to one or more layers and equivalents thereof known to those skilled in the art, and so forth.

[0056] In addition, the words “comprises,” “includes,” and “contains,” when used in this specification and the appended claims, are intended to indicate the presence of stated features, integers, components, or operations, but they do not preclude the presence or addition of one or more other features, integers, components, operations, actions, or groups.

Claims

1. A method for etching a germanium-containing material, the method comprising: flowing the plasma effluent through apertures defined in a chamber component, wherein the apertures are coated with a catalytic material; reducing the concentration of free radicals in the plasma effluent with the catalytic material; delivering the plasma effluents to a processing region of a semiconductor processing chamber, wherein a substrate including a germanium-containing material is received within the processing region; as well as The germanium-containing material is etched.

2. A method for etching a germanium-containing material as described in claim 1, wherein the catalytic material may include one or more materials, and the one or more materials include elements selected from the group consisting of: nickel, cobalt, vanadium, niobium, tantalum, chromium, manganese, rhenium, iron, ruthenium, osmium, palladium, platinum, rhodium and iridium.

3. The method of etching germanium-containing material of claim 1, wherein the chamber components can be maintained at a temperature greater than about 70°C.

4. The method of etching germanium-containing material of claim 1, wherein the substrate can be maintained at a temperature below about 30°C.

5. The method of etching a germanium-containing material of claim 1, wherein the germanium-containing material comprises SiGe, and wherein the plasma effluents are formed from a fluorine-containing precursor.

6. The method of etching a germanium-containing material of claim 1, wherein the germanium-containing material is a first germanium-containing material, and wherein the first germanium-containing material can be etched relative to silicon or a second germanium-containing material, and wherein the second germanium-containing material can be characterized by a lower germanium concentration than the first germanium-containing material.

7. The method of etching a germanium-containing material of claim 6, wherein the etching has a selectivity toward the first germanium-containing material relative to the silicon or the second germanium-containing material of greater than or about 300:

1.

8. The method of etching germanium-containing materials of claim 1, wherein the pressure within the processing chamber can be maintained above about 2 Torr.

9. The method of etching germanium-containing materials of claim 1, wherein the chamber component comprises a showerhead or an ion suppressor.

10. A method for etching a germanium-containing material, the method comprising: flowing a plasma effluent of a precursor through a chamber component containing a catalytic material; catalytically converting at least a portion of free radicals in the plasma effluent by the catalytic material; delivering the plasma effluents to a processing region of a semiconductor processing chamber, wherein a substrate including a germanium-containing material is received within the processing region; as well as The germanium-containing material is etched.

11. The method of etching a germanium-containing material of claim 10, wherein the converting comprises forming a material comprising molecules from free radicals on the catalytic material.

12. The method of etching germanium-containing material of claim 10, wherein the chamber components include one or more of a remote plasma unit delivery tube, a baffle, a face plate, an ion suppressor, or a showerhead.

13. A method for etching a germanium-containing material as described in claim 10, wherein the catalytic material may include one or more materials, and the one or more materials include elements selected from the group consisting of: nickel, cobalt, vanadium, niobium, tantalum, chromium, manganese, rhenium, iron, ruthenium, osmium, palladium, platinum, rhodium and iridium.

14. The method of etching germanium-containing material of claim 10, wherein the chamber components can be maintained at a temperature greater than about 70°C.

15. The method of etching germanium-containing material of claim 10, wherein the substrate can be maintained at a temperature below about 30°C.

16. The method of etching germanium-containing material of claim 10, wherein a pressure within the processing chamber is maintained between about 1 Torr and about 30 Torr.

17. A method for etching a germanium-containing material, the method comprising: flowing a plasma effluent of a precursor through an aperture defined in a processing system component, wherein the aperture is coated with a catalytic material, and wherein the processing system component is maintained at a temperature between about 70° C. and about 150° C.; reducing the concentration of free radicals in the plasma effluent with the catalytic material; delivering the plasma effluents to a processing region of a semiconductor processing chamber, wherein a substrate comprising a germanium-containing material is housed within the processing region, and wherein the substrate is maintained at a temperature of less than about 30° C.; and The germanium-containing material is etched.

18. A method for etching a germanium-containing material as described in claim 17, wherein the catalytic material may include one or more materials, and the one or more materials include elements selected from the group consisting of: nickel, cobalt, vanadium, niobium, tantalum, chromium, manganese, rhenium, iron, ruthenium, osmium, palladium, platinum, rhodium and iridium.

19. The method of etching germanium-containing material of claim 17, wherein a pressure within the processing chamber is maintained between about 1 Torr and about 30 Torr.

20. The method of etching germanium-containing material of claim 17, wherein the chamber component comprises a showerhead or an ion suppressor.

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