CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority of U.S. Application No. 63/341,345, filed May 12, 2022, which is incorporated herein by reference for all purposes.

BACKGROUND

[0002] The present disclosure generally relates to the manufacturing of semiconductor devices. More specifically, the disclosure relates to chamber components used in manufacturing semiconductor devices.

[0003] During semiconductor wafer processing, plasma processing chambers are used to process semiconductor devices. Plasma processing chambers are subjected to plasmas of halogen and/or oxygen, which may degrade components in the plasma processing chambers.

Such components may have a void on the surface. If the surface of the component has a void, the surface is more easily eroded by the plasma.

[0004] The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

SUMMARY

[0005] To achieve the foregoing and in accordance with the purpose of the present disclosure, a component for use in a plasma processing chamber is provided. An aluminum cladding is on a surface of an electrically conductive silicon core. An aluminum silicon interface is between the silicon core and aluminum cladding.

[0006] In another manifestation, an edge ring for use in a plasma processing chamber is provided. An aluminum cladding is on a surface of an electrically conductive silicon core ring. An aluminum silicon interface is between the core ring and aluminum cladding.

[0007] These and other features of the present disclosure will be described in more detail below in the detailed description and in conjunction with the following figures.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The present disclosure is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which:

[0009] FIG. 1 is a high level flow chart of an embodiment. [0010] FIG. 2A- FIG. 2D show embodiments of methods for fabricating a component. [0011] FIG. 3 is a cross-sectional view of a portion of a plasma processing chamber.

[0012] FIG. 4 is a schematic view of a plasma processing chamber that may be used in some embodiments.

DETAILED DESCRIPTION

[0013] The present disclosure will now be described in detail with reference to a few preferred embodiments thereof as illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. It will be apparent, however, to one skilled in the art, that the present disclosure may be practiced without some or all of these specific details. In other instances, well-known process steps and/or structures have not been described in detail in order to not unnecessarily obscure the present disclosure.

[0014] Various embodiments described herein provide semiconductor processing chamber components that are resistant to damage by erosion by processes, such as plasma etching, and thus inhibit or minimize consumption of the component that may occur from plasma and etching processes inherent in semiconductor processing systems such as a plasma processing chamber.

[0015] In some plasma processing chambers, an edge ring may be placed around a wafer. A bending plasma sheath at the wafer-to-edge-ring transition ring help to steer/focus ions above the edge ring onto the wafer edge, resulting in better wafer ER uniformity. Consequently, the ion impinging angle to etch features of the wafer edge may be tuned by the sheath profde. Since components of edge ring systems are exposed to etch plasmas, the components of the edge ring systems are subjected to being etched. Some components of edge ring systems are in DC electrical contact with an electrostatic chuck (ESC) in order to provide the same electrical potential as the ESC in order to provide a more uniform sheath thickness around a wafer. Such components may have a low coefficient of thermal expansion (CTE) so that a gap between the ESC and the component has minimal change as the temperature of the component changes so that the electrical coupling between the component and the ESC has minimal changes.

[0016] Electrically conductive component bodies comprising silicon, silicon carbide, or carbon, such as graphite, have been electroplated with pure aluminum and then anodized to form components of an edge ring system. Electroplating a pure aluminum coating causes defects, such as voids, in pure aluminum coating. Anodizing the pure aluminum coating results in a pure aluminum anodized coating with defects, such as voids. It has been found that such a component may become subject to a corrosive plasma erosion due to the defects. The plasma erosion may cause flaking, undercutting, and pitting. As a result, the component may need to be replaced after 500 radio frequency (RF) hours (hours of processing using RF power). Replacing the component requires machine downtime. In addition, the machine would later need to be run and reconditioned after the component is replaced. If the component has no defects, such as voids, the component may last the lifetime of the machine or may be changed less often, decreasing downtime and cost of ownership, which increases throughput. An aluminum foil may be wrapped around a component and then subsequently anodized. Wrapping foil around a component body creates seams in the foil. The seams would be locations where plasma would erode anodized coatings and/or the component body.

[0017] To facilitate understanding, FIG. 1 is a high level flow chart of a process of some embodiments of fabricating and using a component for a semiconductor processing chamber such as a plasma processing chamber. A component body is provided (step 104). The component body comprises an electrically-conductive material having a low coefficient of thermal expansion (CTE) (e.g., less than lO.OxlO ^-6 /K or less than 5.0xl0 ^-6 /K), such as silicon. The electrical conductivity and low-CTE of the component body are particularly beneficial attributes for use in components of semiconductor processing chambers such as plasma processing chambers. In some embodiments, the component body is made of a material that is not magnetic. If the component body had magnetic properties, the component body would have increased RF power loss due to a thin skin depth. This is because RF current only flows within the skin depth of a conductor, while magnetic materials have very thin skin depths leading to more resistive loss for RF power when flowing through the skin depth.

[0018] FIG. 2A is a cross-sectional schematic view of the formation of components used in some embodiments. In some embodiments, a ring shaped component body 204 with a T shaped cross-section is provided. In some embodiments, the component body 204 is an electrically conductive silicon component body, also called an electrically conductive silicon core or silicon body. In some embodiments, the component body 204 forms a ring, so that the component body 204 forms an electrically conductive core ring. In some embodiments, the core ring is used in an edge ring system of a plasma processing chamber. In various embodiments, metal pieces 208a and 208b are machined to form apertures 210 to accommodate the component body 204. In some embodiments, the metal pieces 208a, 208b are aluminum. In some embodiment, the aluminum metal pieces 208a, 208b are aluminum alloy parts made of aluminum alloy, such as A16061. A16061, which has a Unified Numbering System (UNS) designation A96061, is a precipitation-hardened aluminum alloy, containing magnesium and silicon major alloying elements. In some embodiments, the A16061 aluminum alloy is treated with a T6 temper. An example of a T6 temper that may be used in some embodiments would heat the A16061 to a temperature of about 500° C for about 10 minutes and then provides a quench, such as a water quench. The A16061 is then heated to about 150° C for about 18 hours. Other known T6 temper processes may be used. In some embodiments, the aluminum alloy is between 80% and 99% aluminum by weight.

[0019] The metal pieces are brazed around the component body (step 108). In some embodiments, a metal brazing with a melting temperature that is lower than the melting temperature of the metal pieces 208a, 208b is used for the metal brazing. In some embodiments at least one of A14043, A14343, and A14047 is used as the brazing material. A14043, A14343, and A14047 are aluminum alloys used in brazing or welding. For example, A14047 is an aluminum alloy with 11% to 13% silicon by weight. A14043 is an aluminum alloy with 4.5% to 6% silicon by weight. A14343 is an aluminum alloy with about 7% to 8% silicon by weight. In some embodiments, an oxygen free brazing, such as vacuum brazing or brazing with an inert gas or brazing with a magnesium getter, is used to prevent oxygen from being present during the brazing in order to prevent the formation of aluminum oxide. In some embodiments, the brazing with A14047 heats the metal pieces 208a, 208b to a temperature of more than 500° C. In some embodiments, the brazing temperature is in the range of 570° C to 670° C. The brazing temperature should be high enough to provide melting to form a eutectic mixture of aluminum and silicon and the melting of the brazing material, but low enough to be below the melting point of aluminum metal pieces and to be below the melting point of silicon. The brazing temperature causes a diffusion bond between the metal pieces 208a, 208b and in addition forms an aluminum silicon interface bond between the metal pieces 208a, 208b and the silicon component body 204. In some embodiments, an aluminum alloy brazing filler is placed between the metal pieces and the silicon component body 204 to form part of the aluminum silicon interface. In other embodiments, an aluminum alloy brazing filler is not used, but instead surfaces of the metal pieces 208a, 208b and the silicon component body are used to form the aluminum silicon interface. In some embodiments, the brazing provides a pressure on the metal pieces 208a, 208b removing any gap between the metal pieces 208a, 208b and the silicon component body 204. The contact between the metal pieces 208a, 208b and the silicon component body 204 facilitates the formation of the aluminum silicon interface. [0020] FIG. 2B is a cross-sectional schematic view after the metal pieces 208a, 208b have been brazed around the component body 204. The brazing component 212 is not drawn to scale, in order to illustrate the brazing component 212 more clearly 212, where in some embodiments, the brazing component 212 is A14047. In some embodiments, the brazing component 212 has an average thickness in the range of 0.5 mils (12.7 pm) to 10 mils (254 pm). The braze should have some thickness to ensure a reliable and sound joint to ensure a vacuum seal. In some embodiments, the aluminum silicon interface 214 has a thickness in the range of about 30 p.m to 300 pm. In some embodiments, the aluminum silicon interface 214 is a eutectic of aluminum and silicon where the concentration of silicon is a gradient with the highest concentration of silicon near the component body 204 and decreasing concentrations of silicon further away from the component body 204. The aluminum silicon interface 214 is formed by the surface of the component body 204 and the metal pieces 208a, 208b partially melting together in a eutectic system where the melting temperature of aluminum and silicon is lowered. The aluminum silicon interface 214 forms a bond between the component body 204 and the metal pieces 208a, 208b.

[0021] The metal pieces are machined to form the metal pieces into a cladding (step 112). In some embodiments, the machining provides a cladding with an average thickness in a range of between about 80 m to 3000 pm. Some embodiments have a cladding with an average thickness in a range between about 100 pm to 2000 p.m. The machining process may include one or more of grinding, milling, tuning, and polishing.

[0022] FIG. 2C is a cross-sectional schematic view after the metal pieces 208a, 208b and brazing component have been machined to form a cladding 216 comprising the metal pieces 208a, 208b, and brazing component 212. The component body 204 and cladding 216 form the component 220. The cladding 216 is not drawn to scale, in order to illustrate the cladding 216 more clearly. In some embodiments, the aluminum silicon interface 214 is not anodized.

[0023] In some embodiments, an optional thermal treatment process may be used on the component 220. In some embodiments, the brazing at a temperature of greater than 200° C, reduces mechanical strength provided by the T6 temper. In some embodiments, the thermal treatment heats the component to a temperature of at least 200° C. In some embodiments, the thermal treatment heats the component to a temperature in the range of 500° C to 660° C. The thermal treatment may also reduce mechanical stress caused by the brazing process [0024] In some embodiments, a precision machining may be provided after the first machining or after the thermal treatment. The precision machining may be used to provide an accurate final dimension and good surface finish for high film quality in subsequent anodization. [0025] The cladding is anodized (step 120). In some embodiments, a Type III anodization process is used to anodize the cladding forming a Type 111 anodized aluminum alloy cladding. The Type III anodization process (also referred to as hard anodization or hard-coat anodization) is a process where an aluminum component body is subjected to a sulfuric bath at a temperature of 0 C to 3 ° C and high voltage (up to 100V) to create the oxide or “anodized” layer. In other embodiments, a Type II anodization process is used to anodize the cladding forming a Type II anodized aluminum alloy cladding. The Type II anodization process is where the cladding is placed in a sulfuric bath at about 20° C to 25° C 68-72 to form an aluminum oxide anodized layer on the surface as well as a depth into the aluminum material.

[0026] FIG. 2D is a cross-sectional schematic view of the component 220 after the cladding has been anodized to form an anodized cladding 224 around the component body 204. The anodized cladding 224 is not drawn to scale, in order to illustrate the cladding 216 more clearly. In some embodiments, the anodized cladding 224 encapsulates the entire component body 204.

[0027] The component is mounted in a plasma processing chamber (step 124). FIG. 3 illustrates a cross-sectional view of a portion (defined by section B-B shown in FIG. 4) of an ESC assembly 300 having a movable edge ring configuration for use in a plasma processing system. ESC assembly 300 includes a top edge ring 324 configured to surround an electrostatic chuck (ESC) 304. ESC 304 may also be referred to as a substrate support that acts as a support for process wafer 466 during processing. The top edge ring 324 has an annular lower recess 326 that is supported by a movable edge ring 308. The movable edge ring 308 is disposed to vertically articulate within a cavity defined by an inner radial side comprising the ESC 304, heating plate 352, and middle inner edge ring 328, and an outer radial side comprising a static edge ring 316, outer edge ring 312 and cover edge ring 320. The cover edge ring 320 has a radial inner protrusion 322 partially covering the top edge ring 324.

[0028] Because the top edge ring 324 is exposed to erosive plasma and etchants in the processing of process wafer 466, it invariably becomes worn and thus its thickness is reduced in height with increasing exposure. Accordingly, the movable edge ring 308 is used to raise the top edge ring 324 to restore the height relationship between a top surface of the top edge ring 324 and the process wafer/substrate 466. To affect such height adjustment, one or more lift pins 340 are vertically actuated (through an aperture 348 in the ESC 304 and aperture 318 in static edge ring 316) to push up the movable edge ring 308, which in turn adjusts the vertical orientation of the top edge ring 324. A sleeve 344 is disposed about the circumference of the lift pin 340 to seal off the aperture 348 of the ESC 304.

[0029] Due to its location in the chamber and proximity /exposure to plasma in the processing of process wafer 466 (i.e., bearing one or more “plasma-facing surfaces”), the static edge ring 316 benefits greatly from the anti-corrosion properties. In an example, plasma may pass between the top edge ring 324 and the outer edge ring 312 and cover edge ring 320 to an outer surface of the movable edge ring 308 and an inner surface of the static edge ring 316. The amount of plasma that is passed is dependent on the position of the top edge ring 324. In addition, in the position shown in FIG. 3, the top edge ring 324 may prevent plasma from passing between the top edge ring 324 and the middle inner edge ring 328 and/ or outer edge ring 312 to the inner or outer surfaces of the movable edge ring 308. When the movable edge ring 308 raises the top edge ring 324, a gap is made between the top edge ring 324 and the middle inner edge ring 328 and/ or outer edge ring 312 allowing plasma to reach the surfaces of the movable edge ring 308 and static edge ring 316.

[0030] In some embodiments, the static edge ring 316 has an anodized aluminum cladding. In some embodiments, the movable edge ring 308 has an anodized aluminum cladding. In some embodiments, the static edge ring 316 and/or the movable edge ring 308 have at least one plasma facing surface. A plasma- facing surface is a surface that is either exposed to a plasma during plasma processing or is exposed to a reactive halogen species at high temperature and low pressure. The reactive halogen species may be formed from a remote plasma or thermally reactive fluorine. In some embodiments, the entire surface of the edge ring 316 comprises anodized aluminum.

[0031] To facilitate understanding, FIG. 4 schematically illustrates an example of a plasma processing chamber system 400 that may be used in some embodiments. The plasma processing chamber system 400 includes a plasma reactor 402 having a plasma processing chamber 404 therein. A plasma power supply 406, tuned by a power matching network 408, supplies power to a transformer coupled plasma (TCP) coil 410 located near a dielectric inductive power window 412 to create a plasma 414 in the plasma processing chamber 404 by providing an inductively coupled power. A pinnacle 472 extends from a chamber wall 476 of the plasma processing chamber 404 to the dielectric inductive power window 412, forming a pinnacle ring. The pinnacle 472 is angled with respect to the chamber wall 476 and the dielectric inductive power window 412. For example, the interior angle between the pinnacle 472 and the chamber wall 476 and the interior angle between the pinnacle 472 and the dielectric inductive power window 412 may each be greater than 90° and less than 180°. The pinnacle 472 provides an angled ring near the top of the plasma processing chamber 404, as shown. The TCP coil (upper power source) 410 may be configured to produce a uniform diffusion profile within the plasma processing chamber 404. For example, the TCP coil 410 may be configured to generate a toroidal power distribution in the plasma 414. The dielectric inductive power window 412 is provided to separate the TCP coil 410 from the plasma processing chamber 404 while allowing energy to pass from the TCP coil 410 to the plasma processing chamber 404. A wafer bias voltage power supply 416 tuned by a bias matching network 418 provides power to ESC assembly 300 to set the bias voltage when a process wafer 466 is placed on the ESC assembly 300. A controller 424 controls the plasma power supply 406 and the wafer bias voltage power supply 416.

[0032] The plasma power supply 406 and the wafer bias voltage power supply 416 may be configured to operate at specific radio frequencies such as for example, 13.56 megahertz (MHz), 27 MHz, 1 MHz, 2 MHz, 60 MHz, 400 kilohertz (kHz), 2.54 gigahertz (GHz), or combinations thereof. Plasma power supply 406 and wafer bias voltage power supply 416 may be appropriately sized to supply a range of powers in order to achieve the desired process performance. For example, in one embodiment, the plasma power supply 406 may supply the power in a range of 50 to 5000 Watts, and the wafer bias voltage power supply 416 may supply a bias voltage in a range of 20 to 3000 volts (V). In addition, the TCP coil 410 and/or the ESC assembly 300 may be comprised of two or more sub-coils or sub-electrodes. The sub-coils or sub-electrodes may be powered by a single power supply or powered by multiple power supplies.

[0033] As shown in FIG. 4, the plasma processing chamber system 400 further includes a gas source/gas supply mechanism 430. The gas source 430 is in fluid connection with plasma processing chamber 404 through a gas inlet, such as a gas injector 440. The gas injector 440 has at least one borehole 441 to allow gas to pass through the gas injector 440 into the plasma processing chamber 404. The gas injector 440 may be located in any advantageous location in the plasma processing chamber 404 and may take any form for injecting gas. Preferably, however, the gas inlet may be configured to produce a “tunable” gas injection profile. The tunable gas injection profile allows independent adjustment of the respective flow of the gases to multiple zones in the plasma process chamber 404. More preferably, the gas injector is mounted to the dielectric inductive power window 412. The gas injector may be mounted on, mounted in, or form part of the power window. The process gases and by-products are removed from the plasma process chamber 404 via a pressure control valve 442 and a pump 444. The pressure control valve 442 and pump 444 also serve to maintain a particular pressure within the plasma processing chamber 404. The pressure control valve 442 can maintain a pressure of less than 1 Torr during processing. The gas source/gas supply mechanism 430 is controlled by the controller 424. A Kiyo®, Strata®, or Vector® by Lam Research Corp.® of Fremont, CA, may be used to practice an embodiment.

[0034] A process wafer 466 is placed in the plasma processing chamber 404, and in particular on or within the ESC assembly 300, as shown in FIG. 3. A plasma process is applied to the process wafer 466 (e.g., step 128 of FIG. 1). In some embodiments, the plasma processing of the process wafer 466 is used to provide an etch of part of a stack on the process wafer 466, such as for etching a tungsten-containing layer in the stack. In this embodiment, the plasma process heats the process wafer 466 and ESC assembly 300 to a temperature above 550° C. In addition, the plasma process deposits residue on the interior of the plasma processing chamber 404. After the plasma processing of the process wafer 466, the process wafer 466 is removed from the plasma processing chamber 404. The plasma processing chamber 404 is cleaned to remove deposited residue. In some embodiments, a reactive fluorine from a remote fluorine plasma is used to clean the interior of the plasma processing chamber 404. A pressure in the range of 1 milliTorr (mTorr) to 10 Torr is provided. The ESC assembly 300 has not sufficiently cooled and remains at a temperature above 500° C. After the cleaning is completed, a new process wafer 466 may be placed in the plasma processing chamber 404 to begin a new cycle. In some embodiments, the plasma processing is used to provide an etch of at least one of a carbon layer, poly silicon layer, and oxide/nitride layer. In some embodiments, the wafer temperature is controlled in the range of 0° C to 150° C and the chamber is cleaned after wafer processing by in-situ oxygen (O2) and nitrogen trifluoride (NF3) plasma.

[0035] In various embodiments, the core with the anodized aluminum alloy cladding may be implemented in various parts of a plasma processing chamber 404, such as confinement rings, edge rings, the electrostatic chuck, ground rings, chamber liners, door liners, the pinnacle, a showerhead, a dielectric power window, gas injectors, edge rings, ceramic transfer arms, or other components. While the component 220 and ESC assembly 300 are shown in the embodiments of FIG. 3 with reference to use in an inductively coupled plasma (ICP) reactor for the plasma processing chamber system 400 shown in FIG. 4, it is appreciated that other components and/or types of plasma processing chambers may be used. Examples of other types of plasma processing chambers in which the component 220 may be used are capacitively coupled plasma processing chambers (CCPs), bevel plasma processing chambers, and the like processing chambers. In another example, the plasma processing chamber may be a dielectric processing chamber or conductor processing chamber. An example of such a plasma processing chamber is the Exelan Flex® etch system manufactured by Lam Research Corporation® of Fremont, CA.

[0036] In some embodiments, the anodized cladding 224 has zero void defects. In some embodiments, the A16061 with T6 Temper has no defects. The cladding and anodization process does not cause defects and/or voids so that the resulting anodized cladding 224 has no defects. The defect here is defined as the void with the depth all the way connected to the substrate material under the cladding layer. The most common way to measure void defects is the use of an optical microscope. The lack of defects, such as voids, provides an anodized cladding that is more erosion resistant in order to reduce flaking and pitting of the anodized cladding and avoid the plasma attack of substrate made from etchable materials (e.g., silicon, silicon carbide, or carbon). In some embodiments, the anodized cladding allows the component to last for the lifetime of a plasma processing chamber. The anodized cladding is seamless or has an aluminum alloy seam that has been anodized. A16061 provides a good anodization layer. In some embodiments, an optional notch may be in the cladding. In some embodiments, the aluminum silicon interface 214 prevents delamination between the anodized cladding 224 and the component body 204 over a temperature range.

[0037] While this disclosure has been described in terms of several preferred embodiments, there are alterations, permutations, modifications, and various substitute equivalents, which fall within the scope of this disclosure. It should also be noted that there are many alternative ways of implementing the methods and apparatuses of the present disclosure. It is therefore intended that the following appended claims be interpreted as including all such alterations, permutations, and various substitute equivalents as fall within the true spirit and scope of the present disclosure. As used herein, the phrase “A, B, or C” should be construed to mean a logical (“A OR B OR C”), using a non-exclusive logical “OR,” and should not be construed to mean ‘only one of A or B or C. Each step within a process may be an optional step and is not required. Different embodiments may have one or more steps removed or may provide steps in a different order. In addition, various embodiments may provide different steps simultaneously instead of sequentially.