WO2022093273A1

WO2022093273A1 - Rf delivery and feedthrough assembly to a processing chamber

Info

Publication number: WO2022093273A1
Application number: PCT/US2020/058323
Authority: WO
Inventors: Jozef Kudela
Original assignee: Applied Materials, Inc.
Priority date: 2020-10-30
Filing date: 2020-10-30
Publication date: 2022-05-05

Abstract

In plasma processing systems, process gases may be introduced to the chamber via the showerhead assembly which may be driven as an RF electrode. A toroid is provided with one or more wire windings around the toroid, the wire being coupled to an RF power source. An RF electrode shaft is provided in the opening of the toroid, with the combination being a transformer that provides RF current along the RF electrode shaft. The RF electrode shaft may be a hollow tube having walls thicker than a skin penetration of the RF current. The RF electrode shaft is coupled to the showerhead assembly, and a feedthrough is provided via the hollow portion to the showerhead for distribution into the chamber. The inside of the hollow portion may be at a low or zero RF field to avoid premature gas breakdown that could otherwise lead to parasitic plasma in the hollow portion.

Description

RF DELIVERY AND FEEDTHROUGH ASSEMBLY TO A PROCESSING CHAMBER

BACKGROUND

Field

[0001] Embodiments of the present disclosure generally relates to RF current generation, and more particularly to RF generation on an electrode via a transformer.

Description of the Related Art

[0002] As demand for larger flat panel displays continues to increase, so must the size of the substrate and hence, the processing chamber. As panel size increases, a higher power RF field is sometimes necessary. One method for depositing material onto a substrate for flat panel displays or solar panels is plasma-enhanced chemical vapor deposition (PECVD). In PECVD, process gases may be introduced into the process chamber through a showerhead and ignited into a plasma by an RF field applied to the showerhead. As substrate sizes increase, the RF field applied to the showerhead may also correspondingly increase. With the increase in RF field in process gas or chamber clean gas feed throughs, the possibility of premature gas breakdown prior to the gas passing through the showerhead increases as does the possibility of parasitic plasma formation above the showerhead.

[0003] Therefore, there is a need in the art for an RF power delivery and gas feed through to reduce premature gas breakdown and parasitic plasma formation.

SUMMARY

[0004] The present disclosure generally relates to plasma processing systems in which process gasses may be introduced to the chamber via the RF driven showerhead assembly, or showerhead electrode, while keeping the gasses in RF field free zones. A toroidal transformer is used for coupling RF power to the showerhead electrode, surrounding an electrode shaft coupled to the showerhead electrode. The toroidal transformer is formed by providing a toroid core with one or more wire windings around the toroid that forms the primary coil of an RF transformer. The RF electrode shaft is positioned in the opening of the toroid, forming a single-turn secondary winding of the RF transformer. The RF transformer excites an RF current along the RF electrode shaft. The RF electrode shaft may be a hollow tube having walls thicker than a skin-depth penetration of the RF current, preventing electromagnetic fields from penetrating into a hollow area of the shaft. One end of the RF electrode shaft is coupled to a showerhead, and a gas is provided to the showerhead via the hollow portion to the showerhead. The RF electrode shaft is further coupled to a grounded enclosure. The inside of the hollow portion may be at a low or zero RF field to avoid premature gas breakdown that may lead to parasitic plasma in the hollow portion.

[0005] The electrode shaft hollow can also be used for delivery of heating or cooling fluids, or for bringing electrical connection and circuitry like electric heaters or sensors into RF driven electrode, all of which require low or zero electric fields to function reliably.

[0006] In one embodiment, a substrate processing tool is disclosed, including an RF drive assembly that includes a core having an opening, a coil wound about a portion of the core, the coil coupled to an RF generator via RF match or directly, and an RF electrode shaft is disposed in the opening, the RF electrode shaft comprising a hollow portion extending therethrough. The substrate processing tool further includes a showerhead coupled to the RF electrode, an interior opening of the showerhead communicatively coupled to a first end of the hollow portion of the RF electrode shaft.

[0007] In another embodiment, a substrate processing tool is disclosed that includes an RF drive assembly. The RF drive assembly includes a core having an opening, a coil wound about a portion of the core, the coil coupled to an RF generator, an RF electrode shaft disposed in the opening, the RF electrode comprising a hollow portion, and a susceptor coupled to the RF electrode, an interior opening of the susceptor communicatively coupled to a first end of the hollow portion of the RF electrode.

[0008] In another embodiment, a substrate processing tool is disclosed, that includes an RF drive assembly. The RF drive assembly includes a core assembly having an opening and comprising a core and windings about the core, an RF electrode shaft disposed in the opening, the RF electrode shaft comprising a hollow portion extending therethrough, and an electrode coupled to the RF electrode shaft, an interior opening of the electrode communicatively coupled to a first end of the hollow portion of the RF electrode shaft.

Brief Description of the Drawings

[0009] So that the manner in which the above-recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only exemplary embodiments and are therefore not to be considered limiting of its scope, and may admit to other equally effective embodiments.

[0010] FIG. 1A depicts a processing chamber with a showerhead RF driven electrode, according to certain embodiments.

[0011] FIG. 1 B depicts an example equivalent circuit diagram of the depicted RF driven electrode and processing chamber of FIG. 1 A.

[0012] FIG. 2 depicts a core assembly for an RF driven electrode, according to certain embodiments.

[0013] FIG. 3 depicts a core assembly for an RF driven electrode comprising a partial coil winding, according to certain embodiments.

[0014] FIG. 4 depicts a core assembly for an RF driven electrode for driving multiple RF frequencies, according to certain embodiments.

[0015] FIG. 5 depicts a showerhead RF-driven electrode comprising multiple core assemblies, according to certain embodiments.

[0016] FIG. 6A depicts a showerhead RF-driven electrode comprising a core assembly and a ferrite, according to certain embodiments.

[0017] FIG. 6B depicts an example equivalent circuit diagram of the showerhead RF-driven electrode of FIG. 6A. [0018] FIG. 7A depicts a showerhead RF-driven electrode comprising ceramic insulators, according to certain embodiments.

[0019] FIG. 7B depicts an example equivalent circuit diagram of the showerhead RF-driven electrode of FIG. 7A.

[0020] FIG. 8A-D depicts embodiments for providing instrumentalities within an RF electrode.

[0021] FIG. 9A-D depicts embodiments of an RF driven electrode.

[0022] FIG. 10A&B depict embodiments of an RF driven electrode other than a showerhead and susceptor, according to certain embodiments.

[0023] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

DETAILED DESCRIPTION

[0024] In the following, reference is made to embodiments of the disclosure. However, it should be understood that the disclosure is not limited to specific described embodiments. Instead, any combination of the following features and elements, whether related to different embodiments or not, is contemplated to implement and practice the disclosure. Furthermore, although embodiments of the disclosure may achieve advantages over other possible solutions and/or over the prior art, whether or not a particular advantage is achieved by a given embodiment is not limiting of the disclosure. Thus, the following aspects, features, embodiments and advantages are merely illustrative and are not considered elements or limitations of the appended claims except where explicitly recited in a claim(s). Likewise, a reference to “the disclosure” shall not be construed as a generalization of any inventive subject matter disclosed herein and shall not be considered to be an element or limitation of the appended claims except where explicitly recited in a claim(s).

[0025] The present disclosure generally relates to plasma processing systems in which process gases may be introduced to the chamber via a showerhead, which may be driven as an RF electrode. A toroid is provided with one or more wire windings around the toroid, the wire being coupled to an RF power source, and forming a primary coil for an RF transformer. An RF electrode shaft is provided as a secondary coil for the RF transformer, within the opening of the toroid, with the combination being a transformer that provides RF current along the RF electrode shaft. The RF electrode shaft may be a hollow tube having walls thicker than a skin penetration of the RF current. One end of the RF electrode shaft is coupled to the showerhead, while the other end is coupled to a grounded chamber enclosure. Gas is provided via the hollow portion to the showerhead for distribution into the chamber. The inside of the hollow portion may be at a low or zero RF field to avoid premature gas breakdown, which may lead to parasitic plasma in the hollow portion.

[0026] In certain embodiments, one or both ends of the RF electrode shaft may be electrically insulated from one or both of the showerhead and the chamber enclosure. These configurations enable a non-zero DC bias on the showerhead, which can be internally produced by plasma or externally added from a power supply. In these embodiments, RF current may be bridged by providing one or more capacitors that electrically couple the RF electrode shaft to the showerhead, chamber enclosure, or both. This configuration may also allow for the addition of an external low frequency bias to the electrode.

[0027] Disclosed embodiments will be illustratively described herein in relation to a plasma-enhanced chemical vapor deposition (PECVD) chamber from AKT, a subsidiary of Applied Materials, Inc., Santa Clara, CA. It is to be understood that the principles of the disclosed embodiments may be equally applicable to any chamber design that may include biasing a showerhead, susceptor, or other components, or chambers that may require energizing a gas into a plasma using an RF current, including but not limited to PECVD chambers. It is also to be understood that the principles described herein are equally applicable to plasma enhanced atomic layer deposition (PEALD) chambers, physical vapor deposition (PVD) chambers, plasma etch and atomic layer etch (ALE) chambers, plasma clean chambers, or any other chamber utilizing plasma as a processing component. [0028] The inventor has discovered that by placing a ferrite core having conductive windings about the core, around a hollow RF electrode shaft of conductive material and providing RF power to the conductive windings, a transformer is formed that provides an RF current along the RF electrode shaft. By communicatively coupling the RF electrode shaft to a showerhead of a processing chamber, the RF current may be applied that enables the showerhead to be the main RF drive, or have a supplemental RF bias to be placed on the showerhead. In some embodiments, this RF power allows for the use of the showerhead as an RF electrode for producing a plasma within the processing chamber. In this context, the core and windings may be similar to a transformer core and primary winding, while the RF electrode shaft is the equivalent of a one-turn secondary coil of the transformer. RF frequencies in range of several tens of kHz to several tens of MHz or up to a few hundreds of MHz can be used. In some embodiments the presented RF drive can only supply a supplemental bias for RF driven electrode, in combination of other means producing the plasma. In some embodiments, multiple transformers can be coupled to multiple electrodes into one processing chamber, or multiple RF electrode shafts of the same electrode in a plasma chamber, or multiple transformers can be coupled to the same electrode shaft. Multiple transformers can be powered from one generator at one frequency, or multiple generators at the same frequency, or can be powered with multiple frequencies.

[0029] As is understood by one of skill in the art, RF current has a “skin effect” in traveling on conductive surfaces. Thus, RF current travels on the surface of a conductive element and penetrates to a certain, predeterminable depth (/.e., the skin depth) of the conductive element. The predeterminable depth may be calculated as a function of the frequency of the RF current, the permeability of the material of the conductive element, and the conductivity of the conductive element. Thus, when a conductive element is thicker than the predetermined depth of the RF current penetration, the RF current may not directly interact with gasses, materials, or other elements that are beyond the skin depth of the RF current or related RF fields. In embodiments of the current disclosure, the walls of the RF electrode shaft are thicker than the skin depth of the RF current or related fields, preventing interaction between the RF current gasses, fluids, electrical wiring, and other elements that may be present within the RF electrode shaft.

[0030] In certain embodiments, the walls of the RF electrode shaft are thicker than the skin depth of the RF current formed thereon, allowing for beneficial use of the hollow portion therethrough. As such, gasses, including processing gasses or excited gasses (e.g., from a remote plasma source) may be passed through the RF electrode shaft to the showerhead. In this context, the showerhead may comprise one or more passageways extending from a top surface of the showerhead and a bottom surface of the showerhead; a plenum may exist within the showerhead and gas introduced into the plenum may be distributed by the showerhead. Because the walls of the RF electrode shaft are thicker than the skin depth of the RF current, there is no interaction between gasses in the RF electrode shaft and the RF fields on an outer wall of the shaft, avoiding the formation of parasitic plasmas in the shaft. Gasses provided via the RF electrode shaft may be provided to the showerhead for distribution as part of operation of the processing chamber. Thermal control fluid tubes may be passed through the RF electrode shaft as well, without being affected by the RF current or RF fields. Additionally, wires may be passed through the RF electrode shaft, connecting to sensors in the showerhead, or to provide power for heaters/heating elements located in the showerhead, or other systems within the electrode (e.g., showerhead, susceptor, or other electrode) assembly, to provide electric power, data, and signals to controllers, heaters, data collection, and other systems external to the processing chamber. Any other instrumentality may be provided to the showerhead via the RF electrode shaft, avoiding the effect of generated RF current.

[0031] The use of disclosed embodiments is not limited to developing an RF current in an RF electrode shaft coupled to a showerhead. In certain embodiments, a similar configuration may be used with any RF driven electrode of a processing chamber, such as a susceptor by providing a core with windings that are coupled to an RF power generator, about an RF electrode shaft coupled to a susceptor, in order to provide a bias to the susceptor. Gas may be provided to the susceptor via the RF electrode shaft (e.g., cooling gasses), in addition to providing a pathway for thermal control fluid transport tubes and wires, and other instrumentalities that may benefit from being provided to the susceptor, without interference from the RF current generated by the coil and windings upon the RF electrode shaft.

Example RF Driven Electrodes For a Processing Chamber

[0032] FIG. 1 A depicts a processing chamber 100 having RF driven electrodes for a showerhead and a susceptor, according to certain embodiments. Processing chamber 100 includes a processing chamber enclosure 105, a showerhead 110 for distribution of gasses and a susceptor 115 for holding material for processing, such as a substrate. In this context, a substrate bay comprise a flat panel display substrate, a solar panel substrate, a semiconductor substrate such as a semiconductor wafer, an light emitting display (LED) substrate, or other substrate capable of being processed in a plasma processing chamber. An RF electrode shaft 120 is coupled to the showerhead, and a similar RF electrode shaft is coupled to the susceptor. Although a single RF electrode shaft 120 provided within is discussed, providing one to either the showerhead 110, the susceptor 115, or both, is contemplated. In some embodiments in which only the showerhead 110 is RF driven, the susceptor 115 may be grounded, and concomitantly, in some embodiments in which the susceptor 115 is RF driven, the showerhead 110 may be grounded. In some embodiments multiple electrodes (e.g., showerhead, susceptor, and other electrodes) can be simultaneously RF drive, or DC biased.

[0033] RF electrode shaft 120 may be made of a material such as steel, aluminum, copper, or other metal or conductive alloy may be utilized, or any other material capable of conducting an RF current, or of any non-conductive or semi conductive material having an electrically conductive outer layer provided thereon, of a thickness greater than the skin depth of an RF current generated on the RF electrode shaft 120. The RF electrode shaft 120 has a hollow interior portion, the hollow extending through the RF electrode shaft 120. The walls of RF electrode shaft 120, or conductive outer layer in some embodiments, are of sufficient thickness to prevent an RF current from penetrating the hollow interior portion. Outside of the processing chamber 100, the RF electrode shaft may be coupled to a gas source (not shown) to provide one or more gasses to the processing chamber 100, that may include one or more remote plasma systems (RPS) (not shown) to excite one or more gasses. One or more tubes (discussed below) for the transport of thermal control fluids may be inserted into RF electrode shaft 120, as well as one or more wires (not shown) (e.g., coupled to electric heaters, sensors, or providing a signal to active circuitry or components) for transfer of signal data from the processing chamber 100 and/or showerhead 110. Additional instrumentalities may be provided to the processing chamber 100 and/or showerhead 110 via the RF electrode shaft 120.

[0034] Surrounding a portion of the RF electrode shaft 120 is one or more core(s) 125. Wound about each core 125 are one or more windings 130 of conductive wires coiled about at least a portion of the core 125. A core and one or more groups of windings may be referred to herein as a “core assembly.” In this context, a “winding” is a number of loops of a continuous strand of conductive material about the core 125; there may be multiple windings about a core 125, each group of windings being coupled to a separate RF power source, also referred to as an RF generator, in some embodiments. Core 125 may be comprised of a conductive material such as a ferromagnetic metals or metal compounds such as MnZn ferrites, or a non-conductive material such as NiZn ferrite or other ferrite-ceramics, which may be chosen depending upon the attributes of a desired RF current and frequency to be applied. For example, for a low-frequency RF current different material may be utilized than for higher RF frequencies, as different core materials exhibit higher or lower power losses at different frequencies. Besides ferrites, other material types for core 125 may be chosen. In some embodiments, a non-magnetic material such as a dielectric material may be chosen for core 125, and in these embodiments, windings 130 may substantially cover the core 125. The winding 130 is coupled to RF power 135, and in some embodiments coupled to an RF match 140 that is in turn coupled to the RF power 135. In some embodiments utilizing a dielectric core, the core may be of a solid dielectric material such as alumina, glass, Teflon, or polyimide, or the core may be hollow and filled with a gas such as air.

[0035] Although shown herein as a toroidal shape, the core 125 may be square (e.g., squaroid), triangular, polygonal, or any shape capable of surrounding the RF electrode shaft 120. Moreover, the core 125 may be separable into two or more pieces for ease of placing the winding 130 and/or assembly about the RF electrode shaft 120. [0036] When RF power is applied to the windings 130, an RF current 145 is generated, traveling from the RF electrode shaft 120 to the showerhead 110. Because the walls of the RF electrode shaft 120 are thicker than the skin depth of the generated RF current 1 5, gasses, and other elements are not affected, allowing the RF electrode shaft 120 to serve as a conduit. As can be seen, the RF current 145 flows on the outside of the RF electrode shaft 120, top surface of the showerhead 110, and eventually to a bottom surface of the showerhead 110. Once the RF current reaches the bottom surface of the showerhead 110, gasses present may ignite into a plasma either within the showerhead 110 and/or within a processing space 150 of the processing chamber 100.

[0037] In an alternative embodiment, the configuration described above in connection to providing an RF current to the showerhead 110 may similarly be applied to the susceptor 115. A hollow (or solid) RF electrode shaft may be communicatively coupled to the susceptor 115 so as to provide gas (e.g., a cooling gas such as helium) to the susceptor 115, as discussed below. Alternatively, or in addition, one or more tubes to transport thermal control fluids may be provided in the RF electrode shaft and coupled to the susceptor 115, discussed below, as may be one or more wires coupled to elements in the susceptor e.g., sensors) while being coupled to controllers, data collection, or other systems outside of the processing chamber 100, as discussed below.

[0038] In yet further embodiments, the above-described configurations may be provided simultaneously to both the showerhead 110 and the susceptor 115, and other elements in the processing chamber 100 to which a bias may be applied.

[0039] An RF power source may be similarly coupled to windings about a core, in which is positioned a hollow RF electrode shaft coupled to the susceptor 115, to provide a voltage bias thereto, providing an RF current to the susceptor 115 in a manner similar to that provided to the showerhead 110.

[0040] Although one core assembly comprising core 125 and windings 130 is depicted, there may be more than one core assembly positioned about the RF electrode shaft 120 as discussed below. Moreover, one or more ferrite cores may be additionally positioned about the RF electrode shaft, as discussed below. [0041] FIG. 1 B depicts an equivalent circuit 170 to the processing chamber 100, according to certain embodiments. Equivalent circuit 170 includes an RF power source 172 which may be similar to RF power 135, coupled to a match circuit 174 which may be like RF match 140. In some embodiments match circuit 174 may comprise one or more capacitors 176, or other reactive components such as inductors, however it is understood by one of skill in the art that match circuit 174, like RF match 140 may comprise many types of components in many different configurations.

[0042] Equivalent circuit 170 further includes a transformer 178 that includes a primary coil 180, and a secondary coil 182 comprised of a single winding. The primary coil 180 may be similar to a core assembly comprised of core 125 and windings 130, while the secondary coil 182 may be similar to the RF electrode shaft 120.

[0043] Transformer 178 generates an RF current 184 to a chamber 186 that may be similar to processing chamber 100. Chamber 186 comprises an impedance element 188, that may be similar to an impedance of processing chamber 100.

Example Core for an RF Driven Electrode

[0044] FIG. 2 depicts a core assembly 200 for an RF driven electrode, according to certain embodiments. Core assembly 200 includes a core 205, which may be similar to core 125 of FIG. 1 , windings 210, which may be similar to windings 130 of FIG. 1 , and an RF electrode shaft 215, which may be similar to RF electrode shaft 120 of FIG. 1 . When RF power is provided to the windings 210 from RF power 220, which may be similar to RF power 135 and RF match 140 of FIG. 1 , B-field lines are formed that in turn cause an RF current, such as RF current 145 of FIG. 1 to be developed on the RF electrode shaft 215. In the depicted embodiment, windings 210 are about the entire surface of the core 205.

Example Core for an RF Driven Electrode

[0045] FIG. 3 depicts a core assembly 300 for an RF driven electrode, according to certain embodiments. Core assembly 300 includes a core 305, which may be similar to core 125 of FIG. 1 , windings 310, which may be similar to windings 130 of FIG. 1 , and an RF electrode shaft 315, which may be similar to RF electrode shaft

which may be similar to RF power 135 and RF match 140 of FIG. 1 , B-field lines are formed that in turn cause an RF current, such as RF current 145 of FIG. 1 to be developed on the RF electrode shaft 315. In the depicted embodiment, windings 210 are about a portion of the surface of the core 305.

Example Core for an RF Driven Electrode

[0046] FIG. 4 depicts a core assembly 400 for an RF driven electrode, according to certain embodiments. Core assembly 400 includes a core 405, which may be similar to core 125 of FIG. 1 , first windings 410, which may be similar to windings 130 of FIG. 1 , second windings 412, and an RF electrode shaft 415, which may be similar to RF electrode shaft 120 of FIG. 1. When RF power is provided at an RF powerl 420, which may be similar to RF power 135 and RF match 140 of FIG. 1 , to the first windings 410, and an RF power2 422 from a second RF power source and second RF match circuit, to the second windings 412, B-field lines 430 are formed that in turn cause an RF current, such as RF current 145 of FIG. 1 as a result of the first windings 410 to be developed on the RF electrode shaft 315, and a second RF current as a result of the second windings 412 to be developed on the RF electrode shaft 315. In the depicted embodiment, first windings 410 and second windings 412 are each about a portion of the surface of the core 405. Although not shown, any number of additional groups of windings coupled to RF power sources may be added to develop additional RF currents on the RF electrode shaft 415.

[0047] In such embodiments, multiple frequencies can be combined into one electrode, for example primary frequency of 13.5 MHz and low-frequency bias of 400kHz, and depending on what frequencies and matching circuits are chosen, filters may be used inside the RF powerl 420 and RF power2 422, to eliminate cross-talk between RF powerl 420 and RF power2 422 and potential damage that could result. In some embodiments, the filters can be external between the transformer assembly and the RF power sources.

Example RF Driven Electrode

12 [0048] FIG. 5 depicts a processing chamber 500 comprising an RF driven electrode comprising multiple core assemblies, according to certain embodiments. Processing chamber 500 comprises a first core assembly 505 and a second core assembly 510, coupled to a first RF power 515 and second RF power 520, respectively. An RF electrode shaft 525 is positioned within an opening of the first core assembly 505 and second core assembly 510. The RF electrode shaft 525 is coupled to a showerhead 530. By providing multiple core assemblies about the RF electrode shaft 525, multiple RF currents may be applied thereto, enabling the showerhead 530 to function as an RF driven electrode within the processing chamber 500.

[0049] The RF electrode shaft 525 has a hollow portion with an opening at each end so that one or more gasses may be provided to the showerhead 530, as discussed in connection with FIGs. 8A-D. In addition to, or instead of one or more gasses being provided to the showerhead 530, wires may be positioned within the RF electrode shaft 525, to provide a signal path for one or more sensors positioned within the showerhead 530, as discussed in connection with FIGs. 8A-D. In certain embodiments, one or more fluid transport tubes may be positioned within the RF electrode shaft 525, to provide heating and/or cooling fluids to the showerhead 530, discussed further in connection with FIGs. 8A-D.

[0050] Moreover, one of skill in the art will appreciate that one or more ferrite cores may be positioned about the RF electrode shaft 525, similar to that depicted in FIG. 6.

[0051] Although FIG. 5 is discussed in relation to a showerhead, the disclosed structure and principles may be similarly applied to a susceptor (not shown) or other electrode, for example, similar to the embodiments of FIGs. 9 and 10, positioned within the processing chamber 500.

Example RF Driven Electrode

[0052] FIG. 6 depicts a processing chamber 600 comprising an RF driven electrode for a showerhead, according to certain embodiments. Processing chamber 600 includes a first core assembly 605 comprising a core and windings, which may be similar to core assembly (a combination of core 125 and windings 130 of FIG. 1 ) coupled to RF power 610, which may be similar to RF power 135 and RF match 140, an RF electrode shaft 615 which may be similar to RF electrode shaft 120, a showerhead 620 which may be similar to showerhead 110, and a processing chamber 625 which may be similar to the processing chamber 100. Although one core assembly 606 is shown, additional core assemblies may be added about the RF electrode shaft, for example, to develop further, and/or different, RF currents or frequencies upon the RF electrode shaft.

[0053] Processing chamber 600 further comprises a ferrite 640 disposed about the RF electrode shaft 615, adjacent to one or more core assemblies, coupled to a processing chamber enclosure 625. Although only one ferrite 640 is depicted, there may be one or more additional ferrites, for example, to provide the functionality of an RF Choke as described in US Patent 8,728,586 “RF CHOKE FOR GAS DELIVERY TO AN RF DRIVEN ELECTRODE IN A PLASMA PROCESSING APPARATUS” to Kudela et al., assigned to Applied Materials of Santa Clara, CA, which is incorporated by reference herein in its entirety. For example, in embodiments having one or more ferrites added as shown in FIG. 6, the impedance of the processing chamber 600 may be tuned or otherwise modified, such as to add inductance compensating for capacitive reactance in capacitive-like impedance of the processing chamber 600 to favor the total load impedance to a given RF match, or in some cases, not needing RF match at all. Although one ferrite 640 is shown, additional ferrites may be added about the RF electrode shat, for example, for further tuning of impedance of the processing chamber 600.

[0054] Although the depicted embodiments shows a core assembly and a ferrite in a particular configuration, any number of core assemblies may be provided, and any number of ferrites may be provided in any combination of core assemblies and ferrites. For example, two or more core assemblies may be placed adjacent to each other or two or more ferrites may be placed adjacent to each other, above or below the core assemblies. Core assemblies and ferrites may be interleaved in any ratio.

[0055] As would be appreciated by one of skill in the art, the arrangement described above in connection with the showerhead 620, and variations thereof, may similarly be applied to a susceptor (not shown) or other electrode within the processing chamber 625.

[0056] FIG. 6B depicts an equivalent circuit diagram 670 to the processing chamber depicted in FIG. 6A. Equivalent circuit diagram 670 includes RF power 672 that may be similar to RF power 610, and may include a match circuit. RF power 672 is coupled to a transformer primary coil 674 that may be similar to core assembly 605 that interacts with a transformer secondary coil 676 that may be similar to RF electrode shaft 615. Transformer secondary coil 676 is coupled to an inductor 678 that may be similar to ferrite 640, and inductor 680 that may be similar to processing chamber 600.

Example RF Driven Electrode

[0057] FIG. 7 depicts processing chamber 700 including an RF driven electrode for a showerhead, according to certain embodiments. Processing chamber 700 includes a core assembly 705, which may be similar to core assembly (a combination of core 125 and windings 130 of FIG. 1 ) coupled to RF power 710, which may be similar to RF power 135 and RF match 140, an RF electrode shaft 715 which may be similar to RF electrode shaft 120, a showerhead 720 which may be similar to showerhead 110, and a processing chamber enclosure 725 which may be grounded.

[0058] Processing chamber 700 further includes an insulator break 730 comprised of an insulating material such as a dielectric, that electrically insulates the RF electrode shaft 715 from the processing chamber enclosure 725, and an external pipe 735. The external pipe 736 is coupled to the RF electrode shaft 715 via the insulator break 730. The RF electrode shaft 715 is coupled to the processing chamber enclosure 725 via one or more blocking capacitors 740, which in certain embodiments may be DC blocking capacitors, which may be embedded in the insulator 730. By insulating the RF electrode shaft in this manner, a DC bias may be developed on the RF electrode shaft 715, as well as the showerhead 720. Moreover, one of skill in the art will appreciate that the one or more blocking capacitors 740 may be combined with an inductor, or a variable reactance element, that may be used to tune chamber impedance and control DC bias. [0059] Although blocking capacitors 740 and insulator break 730 are shown insulating the RF electrode shaft 715 from the processing chamber enclosure 725, in certain embodiments blocking capacitors 745 and insulator break 750 may be alternatively or additionally placed to insulate the RF electrode shaft from the showerhead 720, as depicted.

[0060] In some cases, added capacitors to ceramic break can compensate for inductive reactance in cases when having inductive-like impedance of the processing chamber and thus favor the total load impedance to a given RF match, or in some cases to not needing RF match at all.

[0061] As would be appreciated by one of skill in the art, the arrangement described above in connection with the showerhead 720, and variations thereof, may similarly be applied to a susceptor (not shown), or other electrode, positioned within the processing chamber 725.

[0062] FIG. 7B depicts an equivalent circuit diagram 770 of the processing chamber 700. Equivalent circuit diagram 770 includes and RF power 772, which may be like RF power 710, coupled to a primary transformer coil 774, which may be like core assembly 705. Primary transformer coil 774 induces an RF current on a transformer secondary coil 776, which may be like RF electrode shaft 715, which in some embodiments may be the equivalent of a single coil secondary transformer coil. Secondary transformer coil 776 is coupled to a blocking capacitor 778, which may be like blocking capacitor 740 and/or 745, and impedance 780, which may be like processing chamber 700.

Example Instrumentalities within an RF Electrode Shaft

[0063] FIG. 8A-D depicts embodiments for providing instrumentalities within an RF electrode shaft. FIGs. 8A-D each comprise a processing chamber 801 , an RF power 802 which may comprise an RF power generator and an RF match circuit, a core assembly 803 having an opening therein, which may comprise a core comprising one or more windings coupled to RF power 802, an RF electrode shaft 804 disposed within the opening in the core assembly 803, and a showerhead 805 coupled to the RF electrode shaft. The RF electrode shaft 804 comprises a hollow portion therethrough, the hollow portion comprising a first opening 806 to a region outside the processing chamber 801 , and a second opening 807 communicatively coupled to the showerhead 805. Both openings are not exposed to RF fields.

[0064] Although the depicted embodiments utilize the showerhead 805, it is understood that principles described herein may be similarly applied to a susceptor or other element within the processing chamber 801 to which a bias may be applied.

[0065] FIG. 8A depicts an embodiment having a gas source 810 for supplying one or more gasses to the RF electrode shaft 804 via first opening 806, and providing to the showerhead 805 via the second opening 807. The gas source 810, such as process gas or cleaning gas from remote plasma source is in fluid communication with the first opening 806, and gas(es) so supplied may travel along the RF electrode shaft 804 to the second opening 808, and into the showerhead 805, for distribution into the processing chamber 801 .

[0066] FIG. 8B depicts an embodiment having a heating/cooling fluid source 820, for supplying a thermal control fluid within the processing chamber 801 , such as to the RF electrode shaft 804 and/or the showerhead 805. Coupled to the heating/cooling fluid source 820 is one or more supply tubes 822, that may be disposed within the RF electrode shaft 804, being either further provided into the showerhead 805 or coupled to thereto in order to provide thermal control fluid to the showerhead 805.

[0067] FIG. 8C depicts an embodiment having a power source 830, such as an AC or DC power source, coupled to one or more wires 832, being provided to the showerhead 805 via the RF electrode shaft 804. The one or more wires 832 may be heating elements to heat the showerhead 805 and/or coupled to one or more devices disposed within the showerhead.

[0068] Although each of the depictions of FIGs. 8A-D show one core assembly, there may be more than one core assembly, similar to the embodiment depicted in FIG. 5. Moreover, although not shown, there may be a ferrite, similar to ferrite 640 of FIG. 6 positioned about the depicted RF electrode shafts of FIGs. 8A-D, in combination with one or more core assemblies. Also, although not shown, there may be a ceramic break with capacitor or other reactive element, fixed or variable, positioned in the RF electrode shaft of FIGs. 8A-D.

[0069] Although the embodiments of FIGs. 8A-D are depicted in the context of a showerhead, these may be similarly applied to a susceptor, or any other component of a processing chamber that may be driven as an RF electrode.

Example Embodiments of an RF Driven Electrode

[0070] FIG. 9A-D depicts alternative embodiments of an RF driven electrode 900.

[0071] FIG. 9A depicts an example of a processing chamber capable of capacitively coupling a plasma, in which an RF power 901 , is coupled to a core assembly 902 that is positioned about an RF electrode shaft 903. The RF electrode shaft 903 communicatively coupled to a showerhead 904, which may be like showerhead 110, as described elsewhere herein. In the depicted embodiment, a susceptor 905 is coupled to ground. As is understood by one of skill in the art, there may be a match circuit coupling the RF power 901 to the core assembly. As discussed elsewhere herein, the core assembly 902 comprises a core and at least one group of windings about the core, such that the core assembly 902 and RF electrode shaft 903 form a transformer capable of developing an RF.

[0072] In providing RF power to the core assembly 902, an RF current is developed on the RF electrode shaft that is provided to the showerhead 904. By providing such RF current to the showerhead 904, the showerhead 904 may act as an electrode for the formation of a capacitively coupled plasma in the chamber.

[0073] FIG. 9B depicts an example of a processing chamber capable of capacitively coupling a plasma, in which an RF power 910 is coupled to a core assembly 912, positioned about an RF electrode shaft 913. The RF electrode shaft 913 is communicatively coupled to a susceptor 914. In this embodiment, a showerhead 915 is coupled to ground.

[0074] By providing RF power to the core assembly 912, the susceptor 914 may be biased, to participate in the formation of a capacitively coupled plasma in the chamber. [0075] FIG. 9C depicts an example of a processing chamber capable of capacitively coupling a plasma, in which a first RF power 920 is coupled to a first core assembly 921 , positioned about a first RF electrode shaft 922 that is coupled to a showerhead 923. As discussed elsewhere herein, a core assembly such as first core assembly 921 comprises a core having one or more groups of windings to act as a transformer when provided about an RF electrode shaft. A first RF current is developed on the first RF electrode shaft 922 and provided to the showerhead 923 to serve to generate a plasma in the chamber.

[0076] FIG. 9C further depicts a second RF power 925 coupled to a second core assembly 926 that is positioned about a second RF electrode shaft 927 that is in turn, coupled to a susceptor 928. A second RF current is developed on the second RF electrode shaft 927 to bias the susceptor 928, which may participate in the generation of the plasma in the chamber, with the bias provided to the showerhead 923 from the RF current developed on the first RF electrode shaft 922.

[0077] FIG. 9D depicts an example of a processing chamber capable of inductively coupling a plasma, or other type of high-density plasma (HDP), such as microwave coupled from a plasma applicator. A first RF power source 930 is coupled to a coil 931 for developing a high-frequency RF signal into a chamber to generate a high- density plasma. A second RF power 935 is coupled to a first core assembly 936 that is positioned about a first RF electrode shaft 937. The first RF electrode shaft 937 is coupled to a susceptor 938, and configured to provide a bias to the susceptor 938. Although not shown here, in certain embodiments, there may additionally be a showerhead coupled to a second RF electrode shaft positioned within a second core assembly that is powered by a third RF power source, for example, to enable capacitive coupling to the plasma, in addition to, or in some cases to ignite, a plasma that is then further powered by inductive coupling. In another embodiment, a low- frequency bias may be applied to a substrate by susceptor 939 being processed by a HDP.

[0078] Although each of the depictions of FIGs. 9A-D show one core assembly, there may be more than one core assembly, similar to FIG. 5. Moreover, although not shown, there may be one or more ferrites, similar to ferrite 640 of FIG. 6 positioned about the depicted RF electrode shafts of FIGs. 8A-D, in combination with one or more core assemblies. Also, although not shown, there may be a ceramic break with a capacitor or other reactive element, fixed or variable, positioned in the RF electrode shaft of FIGs. 8A-D.

Example Embodiments of an RF Driven Electrode

[0079] FIG. 10A&B depict embodiments of an RF driven electrode other than a showerhead and susceptor, according to certain embodiments.

[0080] FIG. 10A depicts embodiments of a processing chamber 1000, that may be a plasma treatment or plasma pre-clean chamber, that comprises electrode 1005. An RF electrode shaft 1010 that may be similar to RF electrode shaft 120 of FIG. 1 , is coupled to the electrode 1005, and positioned within an opening of a core assembly 1015, that may be like the combination of core 125 and windings 130. The core assembly 1015 is powered by RF power 1020. A susceptor 1025, which may be similar to susceptor 115 is positioned below the electrode 1005. Susceptor 1025 may be grounded or configured as disclosed elsewhere herein, for example as described in connection with FIGs. 1 , 5-8.

[0081] The RF electrode shaft 1010 comprises a hollow portion, communicatively coupled to an opening within the electrode 1005. Heating or cooling fluid transport tubes, wires and/or data collection and control wires, or even one or more gasses may be provided to the electrode 1005 via the hollow portion, similar to the descriptions made in connection with FIGs. 1 , 5-8.

[0082] FIG. 10B depicts embodiments comprising a magnetron type processing chamber 1050, such as a PVD sputtering chamber, that comprises an electrode 1055 that may include embedded magnets or external coils configured to generate B-fields under the electrode 1055. The electrode 1055 is coupled to an RF electrode shaft 1060 that may be similar to RF electrode shaft 120 of FIG. 1 , being positioned within an opening of a core assembly 1065 that may be like the combination of core 125 and windings 130. The core assembly 1065 may be powered RF power 1070. AC/DC power 1070, which may comprise an AC power source, a DC power source, or a pulsed DC power source, is coupled to the RF electrode shaft 1060 to provide power to the electrode 1055. In this embodiment an insulator 1080 insulates the RF electrode shaft 1060 from a chamber enclosure 1090, and one or more blocking capacitors 1085, which in certain embodiments may be DC blocking capacitors, couples the RF electrode shaft 1060 to the chamber enclosure 1090.

[0083] In an alternate embodiment (not shown) the AC/DC power 1070 may be coupled to the electrode 1055. In this embodiment, the insulator 1080 may be positioned between the electrode 1055 and the RF electrode shaft 1060, with the blocking capacitors coupling the electrode 1055 to the RF electrode shaft 1060.

[0084] The RF electrode shaft 1060 comprises a hollow portion, communicatively coupled to an opening within the electrode 1055. Gasses may be provided to the electrode 1055 via the hollow portion, as well as wires for heater elements, control, or data collection, and/or fluid transport tubes coupled to the electrode 1055 may be provided within the hollow portion, similar the embodiments described FIG. 8.

[0085] In some embodiments, similar to those described in FIG. 5, there may be additional core assemblies positioned about the RF electrode shaft 1060. Moreover, similar to FIG. 6, there may be one or more ferrite cores positioned about the RF electrode shaft, in addition to one or more core assemblies.

[0086] A susceptor 1075, which may be similar to susceptor 115, is positioned below the electrode 1055. Susceptor 1075 may be grounded or confirgured as disclose elsewhere herein, for example as described in connection with FIGs. 1 , 5-9.

Further Considerations

[0087] The preceding description is provided to enable any person skilled in the art to practice the various embodiments described herein. The examples discussed herein are not limiting of the scope, applicability, or embodiments set forth in the claims. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments. For example, changes may be made in the function and arrangement of elements discussed without departing from the scope of the disclosure. Various examples may omit, substitute, or add various procedures or components as appropriate. For instance, the methods described may be performed in an order different from that described, and various steps may be added, omitted, or combined. Also, features described with respect to some examples may be combined in some other examples. For example, an apparatus may be implemented, or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of the disclosure is intended to cover such an apparatus or method that is practiced using other structure, functionality, or structure and functionality in addition to, or other than, the various aspects of the disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim.

[0088] As used herein, a phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combination with multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a c c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c).

[0089] As used herein, the term “determining” encompasses a wide variety of actions. For example, “determining” may include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure), ascertaining and the like. Also, “determining” may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory) and the like. Also, “determining” may include resolving, selecting, choosing, establishing and the like.

[0090] The following claims are not intended to be limited to the embodiments shown herein, but are to be accorded the full scope consistent with the language of the claims. Within a claim, a reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” Unless specifically stated otherwise, the term “some” refers to one or more. No claim element is to be construed under the provisions of 35 U.S.C. §112(f) unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.” All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims.

[0091] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

What is claimed is:

1 . A substrate processing tool, comprising: an RF drive assembly, comprising: a core having an opening; a coil wound about a portion of the core, the coil coupled to an RF generator; and an RF electrode shaft disposed in the opening, the RF electrode shaft comprising a hollow portion extending therethrough; and a showerhead coupled to the RF electrode shaft, an interior opening of the showerhead communicatively coupled to a first end of the hollow portion of the RF electrode shaft.

2. The substrate processing tool of Claim 1 , wherein the core is comprised of one of a magnetic material and a dielectric material.

3. The substrate processing tool of Claim 2, wherein a second end of the hollow portion is coupled to a gas source, configured to provide a gas from the gas source to the showerhead.

4. The substrate processing tool of Claim 3, wherein a thickness of a wall of the RF electrode shaft is thicker than a skin effect of an RF current generated on the RF electrode shaft by the coil.

5. The substrate processing tool of Claim 3, wherein one of a wire and a fluid transport tube are positioned within the RF electrode shaft.

6. The substrate processing tool of Claim 1 , further comprising a second core disposed about the RF electrode shaft.

7. The substrate processing tool of Claim 1 , further comprising a second coil wound about a second portion of the core, coupled to one of the RF generator and a second RF generator.

24

8. A substrate processing tool, comprising: an RF drive assembly, comprising a core having an opening; a coil wound about a portion of the core, the coil coupled to an RF generator; and an RF electrode shaft disposed in the opening, the RF electrode comprising a hollow portion; and a susceptor coupled to the RF electrode shaft, an interior opening of the susceptor communicatively coupled to a first end of the hollow portion of the RF electrode.

9. The substrate processing tool of Claim 8, wherein the core is comprised of one of a magnetic material and a dielectric material.

10. The substrate processing tool of Claim 9, wherein a second end of the hollow portion is coupled to a gas source, for providing a gas from the gas source to the susceptor.

11 . The substrate processing tool of Claim 10, wherein a thickness of a wall of the RF electrode shaft is thicker than a skin effect of an RF current generated on the RF electrode shaft by the coil.

12. The substrate processing tool of Claim 8, wherein one of a wire and a fluid transport tube are positioned within the hollow portion.

13. The substrate processing tool of Claim 8, further comprising a second core disposed about the RF electrode shaft.

14. The substrate processing tool of Claim 8, further comprising a second coil wound about a second portion of the core, coupled to one of the RF generator and a second RF generator.

15. A substrate processing tool comprising: an RF drive assembly, comprising: a core assembly having an opening and comprising a core and windings about the core; an RF electrode shaft disposed in the opening, the RF electrode shaft comprising a hollow portion extending therethrough; an electrode coupled to the RF electrode shaft, an interior opening of the electrode communicatively coupled to a first end of the hollow portion of the RF electrode shaft.

16. The substrate processing tool of Claim 15, wherein the electrode comprises one of a showerhead and a susceptor.

17. The substrate processing tool of Claim 15, where one of a wire and a fluid transport tube are positioned within the hollow portion of the RF electrode shaft.

18. The substrate processing tool of Claim 15, wherein a second end of the hollow portion is coupled to a gas source.

19. The substrate processing tool of Claim 15 further comprising a second core disposed about the RF electrode shaft.

20. The substrate processing tool of Claim 19 further comprising a second winding about the second core.