Shower head insert for uniformity tuning

Abstract

To provide a plasma system that achieves uniformity of an electromagnetic field during wafer processing and consistently maintains the uniformity.SOLUTION: A showerhead insert 902 above a showerhead 802 in a wafer processing chamber is utilized in order to alter an electric field 904 near a wafer processing region and to correct or improve asymmetry in a quad station process module (QSM). The insert may comprise an annular body. The annular body has at least one surface thereon including a material for supporting electromagnetic coupling when energized by a RF power source and an annulus of the annular body sized to accommodate a stem 906 of the showerhead. A configuration of the insert is selected so as to affect or correct an asymmetry of an electromagnetic field or plasma generated in the processing chamber during use.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] Claiming priority This application claims the benefit of priority to U.S. Patent Application No. 62 / 854,193, filed May 29, 2019, which is incorporated herein by reference in its entirety.

[0002] The present disclosure relates to showerhead inserts, and in some examples, to showerhead inserts for quad station process modules (QSMs) in semiconductor manufacturing applications. [Background technology]

[0003] The description of the background art provided herein is intended to provide a general background to the present disclosure, and the work of the inventors named herein, to the extent described in this Background Art, together with aspects of the description that would not ordinarily be considered prior art at the time of filing, are not admitted, expressly or impliedly, as prior art to the present disclosure.

[0004] To control the plasma processing, a plasma system is utilized. The plasma system typically includes multiple radio frequency (RF) sources, an impedance matcher, and a plasma reactor. A workpiece (e.g., a substrate or wafer) is placed in the plasma chamber, and a plasma is generated in the plasma chamber to process the workpiece. Often, uniform or repeatable processing of the workpiece is an important production goal. To this end, it can be important to achieve and consistently maintain uniformity of the electromagnetic field during wafer processing. This can be particularly challenging, for example, in asymmetric plasma chambers. Summary of the Invention

[0005] The present disclosure generally relates to showerhead inserts (also referred to as showerhead liners) and, in some applications, to showerhead inserts for QSM. One or more of the processing modules or stations in the QSM can be asymmetric. A molded insert above the showerhead is utilized to modify the electric field near the wafer processing area and, in some examples, to correct or improve the asymmetry in the QSM processing module. In some embodiments, an insert for a showerhead in a processing chamber is provided. An example showerhead insert for may include a body shaped and configured to associate with a showerhead in a processing chamber, the body having at least one surface thereon that includes a material to support electromagnetic coupling when powered by an RF power source, and a structure on the body sized to accommodate the stem of the showerhead.

[0006] In some instances, the configuration of the insert is selected to affect or modify asymmetries in the electromagnetic fields or plasma generated within the processing chamber during utilization.

[0007] In some instances, at least one surface of the insert includes a rounded or curved portion.

[0008] In some examples, the asymmetry is caused, at least in part, by a mismatch between the walls of the processing chamber or an adjacent processing chamber and a substrate support assembly disposed within the processing chamber, such that the profile of a rounded or curved portion of at least one surface bounding the chamber matches the profile of the substrate support assembly.

[0009] In some examples, the body is an annular body and the structure in the body includes an opening in the annular body sized to accommodate the stem of the showerhead.

[0010] In some instances, at least one surface extends into the opening of the annular body.

[0011] In some instances, at least one surface does not extend into the opening of the annular body.

[0012] In some instances, the at least one surface extends across substantially the entire body of the insert.

[0013] In some examples, at least one surface of the insert is aligned with a wall or surface of a processing chamber or showerhead during use.

[0014] In some examples, at least one surface of the insert is flat and, during use, is inclined relative to a wall or surface of the processing chamber or showerhead.

[0015] In some instances, at least one surface of the insert changes the interior geometry or volume of the processing chamber.

[0016] In certain examples, the insert induces a substantially uniform electromagnetic field around a substrate support assembly disposed within the processing chamber.

[0017] In certain examples, the insert induces a substantially non-uniform electromagnetic field around a substrate support assembly disposed within the processing chamber.

[0018] In some examples, the showerhead insert can be adjusted, repositioned, or mechanically adjusted in shape or position to modify the electromagnetic field profile within the processing chamber.

[0019] In some embodiments, an insert for a showerhead in a processing chamber includes a body shaped and configured to associate with a showerhead in a processing chamber, the body having at least one surface thereon comprising a material to support electromagnetic coupling when powered by an RF power source, a structure on the body sized to accommodate a stem of the showerhead, an upper surface through which the showerhead stem can pass when the showerhead insert is fitted to the showerhead, and a shaped recessed lower surface comprising at least one curved profile disposed at least partially adjacent to the surface of the showerhead.

[0020] In some examples, the body is an annular body and the structure in the body includes an opening in the annular body sized to accommodate the stem of the showerhead.

[0021] In some examples, the shaped, recessed lower surface of the showerhead insert at least partially defines a free volume sized and configured to receive and surround substantially the entire showerhead.

[0022] In some examples, the spatial distance between the lower surface of the shaped recess of the showerhead and the upper surface of the showerhead insert increases from a radially inner position to a radially outer position of the showerhead insert.

[0023] In some examples, the top surface of the showerhead insert is substantially flat.

[0024] In some examples, the spatial distance between the wall of the opening in the annular body and the stem of the showerhead increases from a higher vertical position to a lower vertical position of the showerhead insert. [Brief description of the drawings]

[0025] Some embodiments are illustrated by way of example, and not limitation, in the light of the accompanying drawings.

[0026] [Figure 1] 1A-1C are schematic diagrams illustrating substrate processing tools in which example showerhead inserts of the present disclosure can be deployed. [Diagram 2] 1A-1C are schematic diagrams illustrating substrate processing tools in which example showerhead inserts of the present disclosure can be deployed. [Diagram 3] 1A-1C are schematic diagrams illustrating substrate processing tools in which example showerhead inserts of the present disclosure can be deployed. [Figure 4] 1A-1C are schematic diagrams illustrating substrate processing tools in which example showerhead inserts of the present disclosure can be deployed.

[0027] [Diagram 5] FIG. 1 is a schematic diagram illustrating an example substrate processing tool with a four-station processing module in which example showerhead inserts of the present disclosure can be installed.

[0028] [Figure 6A] 4 illustrates example electromagnetic field strength around a pedestal, according to an example embodiment. [Figure 6B] 4 illustrates example electromagnetic field strength around a pedestal, according to an example embodiment. [Figure 6C] 4 illustrates example electromagnetic field strength around a pedestal, according to an example embodiment.

[0029] [Figure 7] FIG. 1 illustrates a simplified example of a plasma-based processing chamber that may include a substrate support assembly with an electrostatic chuck (ESC) having water-cooled components that may be utilized with the disclosed subject matter.

[0030] [Figure 8] 2 is a side cross-sectional view of a showerhead, according to an example embodiment.

[0031] [Figure 9] 1 is a side cross-sectional view of a showerhead with a showerhead insert fitted thereto, according to an example embodiment.

[0032] [Figure 10A]1 illustrates an RF current path, according to an example embodiment. [Figure 10B] 1 illustrates an RF current path, according to an example embodiment. [Figure 10C] 1 illustrates an RF current path, according to an example embodiment.

[0033] [Figure 11A] 1 illustrates a top perspective view of a showerhead insert, according to an example embodiment. [Figure 11B] 1 illustrates a bottom perspective view of a showerhead insert, according to an example embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] The following description includes systems, methods, techniques, instruction sequences, and computer program products embodying exemplary embodiments of the present disclosure. In the following description, for purposes of explanation, numerous specific details are set forth in order to facilitate a thorough understanding of the exemplary embodiments. However, it will be apparent to one skilled in the art that the present disclosure can be practiced without these specific details.

[0035] Portions of the disclosure of this patent document may contain material that is subject to copyright protection. The copyright owner has no objection to the copying by anyone of the patent document or patent disclosure as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyrights whatsoever. The following notice applies to any of the data described below and shown in the drawings that form a part of this document. Copyright - Lam Research, Inc., 2019, All Rights Reserved. Although the showerhead insert is described herein with particular reference to a QSM, this application is not intended to be limiting, and other applications are possible and are covered by the appended claims unless the context indicates otherwise.

[0036] Substrate processing systems may be utilized to perform deposition, etching, and / or other processing of substrates, such as semiconductor wafers. During processing, a substrate is positioned on a substrate support within a processing chamber of the substrate processing system. During etching or deposition, a gas mixture including one or more etching gases or gas precursors, respectively, may be introduced into the processing chamber and a plasma may be ignited to activate a chemical reaction.

[0037] A substrate processing system may include multiple substrate processing tools arranged in a fabrication chamber, each of which may include multiple processing modules, and typically, a substrate processing tool includes up to six processing modules.

[0038] 1, a top view of an example substrate processing tool 100 is shown. The substrate processing tool 100 may include multiple processing modules 104. In some examples, each of the processing modules 104 may be configured to perform one or more respective processes on a substrate. A substrate to be processed may be loaded into the substrate processing tool 100 via a port of a load station of an equipment front-end module (EFEM) 108 and then transferred to one or more of the processing modules 104. For example, a substrate may be loaded into each of the processing modules 104 sequentially. Now referring to FIG. 2, an example array 200 of a fabrication chamber 204 including multiple substrate processing tools 208 is shown.

[0039] 3 illustrates a first example configuration 300 including a first substrate processing tool 304 and a second substrate processing tool 308. The first substrate processing tool 304 and the second substrate processing tool 308 are arranged in series and connected by a transfer stage 312, which is under vacuum. As shown, the transfer stage 312 includes a pivoting transfer mechanism configured to transfer a substrate between a vacuum transfer module (VTM) 316 of the first substrate processing tool 304 and a VTM 320 of the second vacuum processing tool 308. However, in other examples, the transfer stage 312 may include other suitable transfer mechanisms, such as a linear transfer mechanism. In some examples, a first robot (not shown) of the VTM 316 may place a substrate on supports 324 located at a first location, the supports 324 are pivoted to a second location, and a second robot (not shown) of the VTM 320 retrieves the substrate from the supports 324 at the second location. In some examples, the second substrate processing tool 308 may include a storage buffer 328 configured to store one or more substrates between processing stages.

[0040] The transfer mechanisms may be stacked to provide two or more transfer systems between the substrate processing tools 308 and 304. The transfer stage 312 may have multiple slots to transport or buffer multiple substrates at a time.

[0041] In the configuration 300 , a first substrate processing tool 304 and a second substrate processing tool 308 are configured to share a single front end equipment module (EFEM) 332 .

[0042] 4 illustrates a second example configuration 400 including a first substrate processing tool 404 and a second substrate processing tool 408 arranged in series and connected by a transfer stage 412. Configuration 400 is similar to configuration 300 of FIG. 3, except that in configuration 400, EFEM 332 has been removed. Thus, a substrate may be loaded directly into the first substrate processing tool 404 via an airlock load station 416 (e.g., using a storage or transport carrier such as a vacuum wafer carrier, a Front Opening Integrated Pod (FOUP), an atmospheric (ATM) robot, or other suitable mechanism).

[0043] The showerhead insert of the present disclosure may be deployed in a four-station processing module (QSM). In some examples, a four-station processing module 500 is provided, as shown in FIG. 5. The QSM 500 includes four processing modules 508 disposed at respective corner stations within a substrate processing tool 500. Each processing module 508 may itself include four substantially right-angled corners, as shown. Each processing module 508 has chamber walls surrounding four wafer processing stations 518, which may include substantially circular support pedestals, as shown. While various configurations of the processing modules 508 are possible, in some examples, the placement of the circular pedestals supporting the circular wafers at the right-angled corners (i.e., non-matching corners) of the processing modules 508 is asymmetrical, providing an asymmetrical environment during wafer processing. This may present significant challenges to electromagnetic field uniformity, at least one challenge that embodiments of the present disclosure seek to address.

[0044] In this regard, reference is made to FIGS. 6A-6C. FIG. 6A is a diagram illustrating the varying electromagnetic field strength around a circular wafer processing station 518 in one of the four processing modules 508 of the QSM 500. The processing module 508 may have a chamber in the RF path that includes a corner or other shape (see, for example, FIGS. 10A-10C below). In the illustrated example, the wafer processing station 518 is not necessarily symmetric about the center of the wafer due to different boundary conditions that may include one chamber corner 604, the spindle region 602, and the adjacent processing station 608. The curved configuration of the rounded chamber corner 604 substantially matches the curved profile of the wafer processing station 518, while the adjacent station 608 and the spindle region 602 do not match the rounded pedestal profile. This non-uniform configuration presents an asymmetry in the chamber shape and may cause the formation of an asymmetric electromagnetic field, as shown by contour lines 610. Asymmetric fields are discussed further below.

[0045] Three radial positions around the example processing station 518 are shown in FIG. 6B at 0°, 45°, and 225° positions, respectively. The example processing station includes a chamber corner and a spindle region as shown. The corresponding electromagnetic field strength is shown for each of these three radial positions in the graph of FIG. 6C. The shape of the electromagnetic field strength line 606 shows that the electromagnetic field strength varies around the periphery of the pedestal 518. This may be primarily caused by the asymmetric shape and environment of the processing module 508. This non-uniform or variable electromagnetic field distribution may present significant challenges in achieving uniform processing conditions across the surface of the wafer.

[0046] Returning to FIG. 5, the QSM 500 includes transfer robots 502 and 504, collectively referred to as transfer robots 502 / 504. The processing tool 500 is shown without a mechanical indexer for illustrative purposes. In other examples, each processing module 508 of the tool 500 may include a mechanical indexer. The VTM 516 and the EFEM 510 may each include one of the transfer robots 502 / 504. The transfer robots 502 / 504 may have the same or different configurations. In some examples, the transfer robot 502 is shown having two arms, each arm having two vertically stacked end effectors. The robot 502 of the VTM 516 selectively transfers substrates to and from the EFEM 510 and between the processing modules 508. The robot 504 of the EFEM 510 transfers substrates into and out of the EFEM 510. In some examples, the robot 504 may include two arms, each having a single end effector or two vertically stacked end effectors.

[0047] A system controller 506 may control various operations of the illustrated substrate processing tool 500 and its components, including, but not limited to, operation of the robots 502 / 504, rotation of the indexers of each of the processing modules 508, etc.

[0048] The tool 500 is configured to couple with, for example, each of four processing modules 508. Each processing module 508 may have a single load station accessible via a respective slot 512. In this example, the sides 514 of the VTM 516 are not angled (i.e., the sides 514 are substantially straight or planar). Other arrangements are possible. As shown, two of the processing modules 508, each having a single load station, are coupled to each of the sides 514 of the VTM 516. Thus, the EFEM 510 may be disposed at least partially between two of the processing modules 508.

[0049] During substrate processing in the process modules 508, process gases enter the modules, for example to assist in the generation of plasma. The gases then exit the process modules 508. The exhaust of waste gases may be performed by a vacuum line or an exhaust line. One of the further exhaust lines may be located below each process module 508 and connected to a vacuum source to exhaust gases from the process modules 508.

[0050] Referring now to FIG. 7, a simple example of a plasma-based processing tool 700 is shown. FIG. 7 shows a plasma-based processing chamber 701A in which a showerhead electrode (or simply a showerhead for simplicity) 703 and a substrate support assembly 707A are disposed. The substrate support assembly 707A may include a pedestal of the type described above. Typically, the substrate support assembly 707A provides a substantially isothermal surface and may function as both a heating element and a heat sink for the substrate 705. The substrate support assembly 707A may include an ESC with a heating element to aid in processing the substrate 705, as described above. The substrate 705 may be a wafer including an elemental semiconductor (e.g., silicon or germanium), a wafer including a compound element (e.g., gallium arsenide (GaAs) or gallium nitride (GaN)), or a variety of other substrate types (conductive substrates, semiconductor substrates, non-conductive substrates, etc.). The plasma-based processing chamber may have some water-cooled components.

[0051] In operation, a substrate 705 is loaded onto the substrate support assembly 707A through a load port 709. A gas line 713 supplies one or more process gases to the showerhead electrode 703. The showerhead electrode 703 in turn supplies one or more process gases to the plasma-based processing chamber 701A. A gas source 711 for supplying one or more process gases is connected to the gas line 713. An RF power source 715 is connected to the showerhead electrode 703 or the substrate support assembly 707A (see, e.g., FIGS. 10A-10C).

[0052] During operation, the plasma-based processing chamber 701A is evacuated by a vacuum pump 717. RF power is capacitively coupled between the showerhead electrode 703 and a lower electrode (not shown) housed in or on the substrate support assembly 707A. The substrate support assembly 707A is typically supplied with two or more RF frequencies. For example, in various embodiments, the RF frequency may be selected from at least one frequency, such as approximately 1 MHz, 2 MHz, 13.56 MHz, 27 MHz, 60 MHz, and other frequencies, as desired. Coils may be designed to block or partially block specific RF frequencies, as desired. Thus, the specific frequencies discussed herein are provided merely for ease of understanding. RF power is used to excite one or more process gases into a plasma in a space between the substrate 705 and the showerhead electrode 703. The plasma may serve to deposit various layers (not shown) on the substrate 705. In other applications, the plasma may be utilized to etch device features in various layers on the substrate 705. As mentioned above, the substrate support assembly 707A may have a heater (not shown) built into it. RF power is coupled through at least the substrate support assembly 707A.

[0053] 8 is a cross-sectional side view of a showerhead 802 (e.g., showerhead 703 described above). The showerhead 802 shown is powered by an external RF power source to generate a number of example electric iso-fields 804 around it. It can be seen that the distribution pattern of the electric iso-fields 804 to the left of the pedestal 802 is different than the pattern to the right of the pedestal 802. The electric iso-fields on the left are more dispersed than their counterparts on the right of the pedestal. This is an example of a non-uniform or asymmetric electromagnetic field. This processing chamber condition can significantly affect the production of consistent semiconductor formations on the surface of a wafer.

[0054] FIG. 9 shows a showerhead 802 fitted with an annular showerhead insert (also referred to as a showerhead liner) 902. In this example, the showerhead insert is fitted around a showerhead stem 906. Other configurations are possible, such as, for example, the insert 902 being supported by the wall of the processing chamber in which the insert is utilized. Note that the distribution pattern of the isoelectric field 904 is substantially the same on both the left and right sides of the showerhead 802. The showerhead insert 902 can provide electromagnetic boundary conditions that result in a more uniform electromagnetic field around the showerhead 802. Because the plasma in the processing chamber is generated by the electromagnetic fields generated therein, the resulting plasma is generally uniform in distribution and effect.

[0055] In some examples, the showerhead insert can configure the profile of the chamber surface (e.g., upper chamber wall, etc.) based on certain factors, such as the process chamber pressure, or the process frequency, or the pedestal-to-showerhead gap, gas composition, and other process parameters. The size, shape, and / or configuration of the showerhead insert can be selected and optimized to cause or improve the production of more uniform and consistent formations on the wafer surface during processing. Utilizing a showerhead liner with an appropriate shape can enable consistent chamber conditions, allowing wafer formation to be controlled and varied as desired.

[0056] In some examples, the showerhead insert 902 can cause a reduction in undesirable electromagnetic fields above the showerhead that can ignite a parasitic plasma in the processing chamber. An appropriate insert shape or configuration can reduce the inductance of the RF path from the showerhead to the chamber walls, which can reduce or change the voltage of the showerhead relative to the chamber walls or "ground" reference. The geometry of the processing chamber can be selected and adapted to provide various processing conditions based on the requirements of the wafer processing.

[0057] In this regard, reference is now made to Figures 10A-10C. In some cases, it may be desirable to correct for asymmetries in a wafer processing chamber, such as, for example, wafer processing module 508. In some instances, certain asymmetries in the processing chamber may actually be desirable. In each of the figures, a wafer processing chamber 1002 is shown. The wafer processing chamber 1002 may be included in, for example, processing module 508 in a QSM. The processing chamber 1002 may be surrounded and defined by chamber walls 1006 including an upper chamber wall 1008 having an initially flat or unaltered surface or configuration. This configuration is shown in Figure 10A.

[0058] Each processing chamber 1002 includes a substrate support assembly 1004, which may include, for example, a circular pedestal 518 (FIGS. 5-6) or 107A (FIG. 7). Each processing chamber 1002 further includes a showerhead 1010, such as showerhead 802 (FIGS. 8-9) or 703 (FIG. 7). Each processing chamber 1002 is powered by an RF power source 1012 (e.g., RF power source 715 in FIG. 7) that can generate an electromagnetic field within each chamber 1002 to form a plasma 1018 between each substrate support assembly 1004 and the showerhead 1010. Arrows 1014 in each of FIGS. 10A-10C indicate the RF current path that generates the electromagnetic field within each processing chamber 1002. The RF current path runs from the RF power source 1012, through the plasma 1018, through the chamber walls 1006 and 1008, and back to the RF power source 1012.

[0059] The shape and strength of the electromagnetic field in the processing chamber 1002 may be configured by a showerhead insert. The showerhead insert may be appropriately configured to induce or adjust the symmetry or asymmetry of the electromagnetic field or plasma. In some examples, the chamber 1002 as shown in FIG. 10A includes a pedestal-fed grounded showerhead 1010 that generates an RF current path as shown.

[0060] 10B, a chamber 1002 may include a pedestal-powered grounded showerhead 1010 and a symmetric annular showerhead insert 1016. The showerhead insert 1016 affects the RF current path 1014 as shown, modifying the electromagnetic field to provide a desired symmetry that may have a beneficial effect on a wafer supported by the substrate support assembly 1004. In this example, the electromagnetic field is symmetric.

[0061] In a further example, a chamber 1002 as shown in FIG. 10C includes a pedestal-powered grounded showerhead 1010 and an asymmetric showerhead insert 1016. The asymmetric showerhead insert 1016 affects the RF current path 1014 non-uniformly as shown and may be utilized to compensate for other asymmetries that may be present in a given RF plasma chamber (such as a QSM500). In this example, the electromagnetic field is asymmetric, but may be utilized to compensate for other asymmetries. FIGS. 11A-11B provide top and bottom perspective views of an example configuration of a showerhead insert 902 for configuring an electromagnetic field in a processing chamber. With reference to FIGS. 11A-11B and FIG. 9, the showerhead insert 902 includes a body 908 shaped and configured to associate with a showerhead (e.g., showerhead 802 of FIG. 9) in a processing chamber. The body 908 has one or more surfaces 910 that include a material to support electromagnetic coupling when powered by an RF power source. The structure 912 on the body 908 is sized to receive a showerhead stem (e.g., showerhead stem 906 in FIG. 9). The showerhead insert 902 includes a top surface 914 through which the showerhead stem (e.g., stem 906) can pass when the showerhead insert 902 is fitted into a showerhead (e.g., showerhead 802). In some examples, the top surface 914 of the showerhead insert 902 is substantially flat, as shown in the figures.

[0062] The showerhead insert 902 includes a shaped, recessed lower surface 916, as can also be seen in cross section in FIG. 9. The lower surface 916 includes at least one curved profile 918 disposed at least partially adjacent a surface of the showerhead 802. This is seen more clearly in FIG. 9. In some examples, the body 908 of the showerhead insert 902 is an annular body, and the structure 912 in the body 908 includes an opening 912 in the annular body 908. The opening 912 is sized to accommodate, for example, the stem 906 of the showerhead 802 shown in FIG.

[0063] The shaped recessed lower surface 916 of the showerhead insert 902 at least partially defines an interior or free volume 920 that is sized and configured to receive and surround substantially the entirety of the showerhead 802, as shown more clearly in Figure 9. In Figure 9, in the illustrated example, it can be seen that the spatial distance between the shaped recessed lower surface 916 of the showerhead insert 902 and the upper surface 924 of the showerhead 802 increases from a radially inner location 922 to a radially outer location 926 of the showerhead insert 802 (i.e., in the direction of arrow 930). In some examples, the spatial distance between the wall of the opening 912 in the annular body 908 and the stem 906 of the showerhead 802 increases from a vertically higher location to a vertically lower location of the showerhead insert 902 (i.e., in the direction of arrow 932).

[0064] Other showerhead insert 902 configurations are possible. Some example embodiments of the showerhead insert 902 may have one or more curved or rounded electromagnetic field engaging surfaces. Other examples may also include one or more substantially flat electromagnetic field engaging surfaces. The surfaces of the showerhead insert 902 may be aligned with the chamber walls or showerhead during use, or may be angled relative to these elements.

[0065] Although the examples have been described with reference to specific example embodiments or method examples, it is apparent that various modifications and changes may be made to these embodiments without departing from the broader scope of the embodiments. The specification and drawings are therefore to be regarded as intended to be illustrative and not restrictive. The accompanying drawings, which form a part of this specification, show, by way of example and not limitation, specific embodiments in which the subject matter may be practiced. The illustrated embodiments are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed herein. Alternative embodiments may be used or derived from this application, in which structural and logical substitutions and changes may be made without departing from the scope of the present disclosure. Thus, the "description of the preferred embodiments" is not meant to be limiting, and the scope of the various embodiments is defined only by the appended claims and all equivalents thereof.

[0066] Such embodiments of the inventive subject matter may be referred to herein individually and / or collectively under the term "invention", which is merely for convenience and is not intended to unnecessarily limit the scope of the present application to any single invention or inventive concept (if more than one is actually disclosed). Thus, although specific embodiments have been shown and described herein, it should be understood that any configuration intended to achieve the same purpose may be substituted for the specific embodiment shown. The present disclosure is intended to cover all adaptations or variations of the various embodiments. Combinations of the above-mentioned embodiments, as well as other embodiments not specifically described herein, will be apparent to one skilled in the art from the above description.

Claims

1. 1. An insert for a showerhead in a processing chamber, comprising: a body shaped and configured to associate with the showerhead in the processing chamber, the body having at least one surface thereon comprising a material for supporting electromagnetic coupling when powered by an RF power source; a structure on the body sized to receive a stem of the showerhead; and The insert comprises:

2. 10. The showerhead insert of claim 1, wherein a configuration of the insert is selected to affect or modify asymmetries in an electromagnetic field or plasma generated within the processing chamber during use.

3. 10. The showerhead insert of claim 1, wherein the at least one surface of the insert includes a rounded or curved portion.

4. 4. An insert as described in claim 3, wherein the asymmetry is caused at least in part by a mismatch between a wall of the processing chamber or an adjacent processing chamber and a substrate support assembly disposed within the processing chamber, such that the profile of the rounded or curved portion of the at least one surface bounding the chamber matches the profile of the substrate support assembly.

5. 10. The showerhead insert of claim 1 , wherein the body is an annular body and the formation on the body includes an opening in the annular body sized to receive the stem of the showerhead.

6. 6. The showerhead insert of claim 5, wherein the at least one surface extends into the opening of the annular body.

7. 6. The showerhead insert of claim 5, wherein the at least one surface does not extend into the opening of the annular body.

8. 10. The showerhead insert of claim 1, wherein the at least one surface extends across substantially the entire body of the insert.

9. 10. The showerhead insert of claim 1, wherein the at least one surface of the insert is aligned with a wall or surface of the processing chamber or the showerhead during use.

10. 10. The showerhead insert of claim 1, wherein the at least one surface of the insert is flat and, during use, is inclined relative to a wall or surface of the processing chamber or the showerhead.

11. 10. The showerhead insert of claim 1, wherein the at least one surface of the insert changes an interior geometry or volume of the processing chamber.

12. 10. The showerhead insert of claim 1, wherein the insert induces a substantially uniform electromagnetic field around a substrate support assembly disposed within the processing chamber.

13. 10. The showerhead insert of claim 1, wherein the insert induces a substantially non-uniform electromagnetic field around a substrate support assembly disposed within the processing chamber.

14. 10. The showerhead insert of claim 1, wherein the insert can be adjusted, repositioned, or mechanically adjusted in shape or position to modify the electromagnetic field profile within the processing chamber.

15. 1. An insert for a showerhead in a processing chamber, comprising: a body shaped and configured to associate with the showerhead in the processing chamber, the body having at least one surface thereon comprising a material for supporting electromagnetic coupling when powered by an RF power source; a structure on the body sized to receive a stem of the showerhead; and a top surface through which the stem of the showerhead can extend when the showerhead insert is fitted to the showerhead; a shaped recessed lower surface having at least one curved profile disposed at least partially adjacent a surface of the showerhead; The insert comprises:

16. 16. The showerhead insert of claim 15, wherein the body is an annular body and the formation on the body includes an opening in the annular body sized to receive the stem of the showerhead.

17. 17. The showerhead insert of claim 16, wherein the shaped, recessed lower surface of the showerhead insert at least partially defines a free volume sized and configured to receive and surround substantially an entirety of the showerhead.

18. 20. The showerhead insert of claim 17, wherein a spatial distance between the shaped recessed lower surface of the showerhead insert and an upper surface of the showerhead increases from a radially inner position to a radially outer position of the showerhead insert.

19. 20. The showerhead insert of claim 18, wherein the top surface of the showerhead insert is substantially flat.

20. 20. The showerhead insert of claim 19, wherein a clearance between a wall of the opening in the annular body and the stem of the showerhead increases from a higher vertical position to a lower vertical position of the showerhead insert.

Images