Mold and method for forming radio frequency (RF) coils for plasma processing equipment

Abstract

Disclosed herein are multiple different embodiments of molds and methods for producing radio frequency (RF) coils. The disclosed mold includes a cylindrical inner core and a two-piece compression sleeve, the cylindrical inner core having a first spiral groove formed in the outer surface of the cylindrical inner core, and the two-piece compression sleeve having a second spiral groove formed in the inner surface of the two-piece compression sleeve. When the parts of the two-piece compression sleeve are attached together, the two-piece compression sleeve surrounds the cylindrical inner core and provides a compressive force to the conductors arranged in the first spiral groove and the second spiral groove to produce the RF coil. In some embodiments, each part of the mold can be produced separately using a three-dimensional (3D) printing process.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of the filing date of U.S. Non-Provisional Patent Application No. 16 / 752,446, filed on January 24, 2020, which is incorporated herein by reference in its entirety. Background Art

[0003] The present disclosure relates to radio frequency (RF) coils used in plasma processing equipment. In particular, the present invention provides various embodiments of molds and methods for forming RF coils.

[0004] Plasma processing equipment is widely used in the production of semiconductor devices and other electronic devices. In such equipment, plasma is used to perform processes such as etching, deposition, oxidation, sputtering, etc., so as to achieve good reaction of the process gas at relatively low temperatures. Conventional plasma processing equipment used for such purposes includes, but is not limited to, capacitively coupled plasma (CCP) and inductively coupled plasma (ICP) equipment.

[0005] In general, plasma is generated in a vacuum chamber, and the device for generating plasma is either located outside the chamber or inside a protective wall to reduce the disturbance of the plasma potential when RF power is applied. In an inductively coupled plasma (ICP) apparatus, for example, a coiled RF antenna may be positioned outside a dielectric window formed in the wall of a processing chamber that serves as a vacuum chamber for the generated plasma. A target substrate (e.g., a semiconductor wafer or a glass substrate) is disposed at a central region within the processing chamber.

[0006] In order to perform plasma processing, a processing gas is supplied into a processing space formed between a dielectric window and a substrate. A high-frequency alternating current (AC) current is supplied to a coil-shaped RF antenna to induce an RF magnetic field, which is transmitted to the processing space in the chamber via the dielectric window. As the RF magnetic field changes with time, an induced electric field is generated in the processing space in an azimuthal direction to generate a strong plasma.

[0007] In some cases, the characteristics of the coiled RF antenna (such as the number of turns, pitch, bend radius, coil diameter, coil length, coil concentricity, etc.) can be changed to affect plasma density and repeatability. For example, changing the geometry of the coil will affect the plasma characteristics based on changing the characteristics such as pitch, diameter, length, etc. (e.g., increasing the pitch of the coil will change the plasma generation region, plasma density, and plasma uniformity).

[0008] RF coil designs are typically handed off to external suppliers for production via a manufacturing process that includes a combination of hand bending and winding machinery. Unfortunately, hand-producing RF coils (with or without the assistance of winding machinery) is not very accurate and often fails to meet the tight tolerances required for plasma processing. The manufacturing process also tends to produce uneven surfaces and warped geometries (e.g., distorted coil shapes), which can affect the near-field behavior of the produced RF coils.

[0009] In some cases, multiple iterations may be required to perfect the RF coil design. For example, tight bend radii, coil concentricity, and coil diameter are particularly difficult to predict and may require adjustments throughout the design process. For example, even small deviations in concentricity may result in non-uniformity in plasma processing, poor ignition behavior, or abnormal discharge. However, many external suppliers have long lead times (e.g., about 4 to 6 weeks), which can significantly increase the design time, especially when multiple iterations are required to perfect the RF coil design.

[0010] There is a need for an improved method of producing RF coils that is accurate, reproducible, and more time / cost effective than conventional manufacturing processes. Summary of the invention

[0011] Disclosed herein are multiple different embodiments of molds and methods for producing RF coils. More specifically, the present disclosure provides multiple different embodiments of molds and methods for producing RF coils used in plasma processing equipment. As discussed in more detail below, the disclosed mold can generally include a cylindrical inner core and a two-piece compression sleeve, the cylindrical inner core having a first spiral groove formed in the outer surface of the cylindrical inner core, and the two-piece compression sleeve having a second spiral groove formed in the inner surface of the two-piece compression sleeve. When the portions of the two-piece compression sleeve are attached together, the two-piece compression sleeve surrounds the cylindrical inner core and provides a compressive force to the conductors arranged in the first spiral groove and the second spiral groove to produce the RF coil.

[0012] In some embodiments, each part of the mold can be produced individually using a three-dimensional (3D) printing process. By using a 3D printing process to produce the molds disclosed herein, the present disclosure provides a method for producing RF coils that is accurate, reproducible, and more time / cost effective than traditional manufacturing processes.

[0013] According to one embodiment, a mold for producing an RF coil for use in a plasma processing device may generally include a cylindrical inner core and a two-piece compression sleeve. The cylindrical inner core may have a first spiral groove formed in an outer surface of the cylindrical inner core, and the two-piece compression sleeve may have a second spiral groove formed in an inner surface of the two-piece compression sleeve. When the portions of the two-piece compression sleeve are attached together, the two-piece compression sleeve may be configured to surround the cylindrical inner core and provide a compressive force to the conductor arranged in the first spiral groove and the second spiral groove to produce the RF coil. In some embodiments, the conductor may include a ferrous or non-ferrous metal, including, for example, but not limited to, copper, aluminum, or iron.

[0014] In some embodiments, the two-piece compression sleeve includes a first portion and a second portion that is removably attached to the first portion by one or more mechanical fasteners. In some embodiments, the two-piece compression sleeve may include a cope portion and a drag portion that help form a negative shape of the portion and help form the portion into a desired shape (e.g., cavity diameter, coil outer diameter, coil pitch, etc.).

[0015] In some embodiments, the shape and size of the mold can be determined to form an RF coil used in a plasma processing device. In such embodiments, the cylindrical inner core can have a height between 1 / 8 inch and 12 inches, a diameter between 1 / 8 inch and 24 inches, a number of turns between 1 and 100, and a pitch between 1 / 8 inch and 2 inches.

[0016] In some embodiments, the mold can be produced by producing each part of the mold separately using a three-dimensional (3D) printing process. For example, in some embodiments, the cylindrical core, the first part of the two-piece compression sleeve, and the second part of the two-piece compression sleeve can each be produced by 3D printing a thermoplastic polymer material having a glass transition temperature of more than 100°C and a compressive strength of more than 200 megapascals (MPa). In other embodiments, other materials capable of 3D printing can be used (for example, but not limited to, carbon fiber-PC, carbon fiber, aluminum, stainless steel, chromium nickel alloy, etc.). Metals are generally stronger and will provide a better and more consistent final shape.

[0017] According to another embodiment, a method for forming an RF coil for use in a plasma processing device is provided. In some embodiments, the method may begin by using a 3D printing process to produce a mold, the mold comprising a cylindrical inner core and a two-piece compression sleeve, wherein a first spiral groove is formed in the outer surface of the cylindrical inner core and a second spiral groove is formed in the inner surface of the two-piece compression sleeve. The method may also include wrapping a portion of the conductor around the cylindrical inner core so that a portion of the conductor is arranged in the first spiral groove. The method may further include applying the two-piece compression sleeve to the cylindrical inner core so that the two-piece compression sleeve surrounds the cylindrical inner core and provides a compression force to a portion of the conductor arranged in the first spiral groove and the second spiral groove to form the RF coil.

[0018] In some embodiments, the use of a 3D printing process to produce the mold may include using a 3D printing process to produce each part of the mold individually. For example, in some embodiments, the cylindrical inner core, the first portion of the two-piece compression sleeve, and the second portion of the two-piece compression sleeve can each be produced by 3D printing a thermoplastic polymer material having a glass transition temperature of more than 100°C and a compressive strength of more than 200MPa. In other embodiments, other materials, in other embodiments, other materials capable of 3D printing (for example, but not limited to, carbon fiber-PC, carbon fiber, aluminum, stainless steel, chromium nickel alloy, etc.) can be used. Metals are generally stronger and will provide a better and more consistent final shape.

[0019] In some embodiments, producing the mold using a 3D printing process may include using a 3D printing process to form a cylindrical inner core having a height between 1 / 8 inch and 12 inches, a diameter between 1 / 8 inch and 24 inches, a number of turns between 1 and 100, and a pitch between 1 / 8 inch and 2 inches.

[0020] In some embodiments, applying the two-piece compression sleeve may include applying a first portion of the two-piece compression sleeve to a first side of the cylindrical inner core, and applying a second portion of the two-piece compression sleeve to a second side of the cylindrical inner core, such that the second portion and the first portion surround the cylindrical inner core and a portion of the conductor. In some embodiments, applying the two-piece compression sleeve may also include attaching the first portion to the second portion by one or more mechanical fasteners to apply a compressive force to a portion of the conductor disposed within the first helical groove and the second helical groove.

[0021] In some embodiments, the method may further include removing one or more mechanical fasteners, removing the first portion and the second portion of the two-piece compression sleeve from the cylindrical inner core and the RF coil, and removing the RF coil from the mold by rotating at least one of the RF coil or the cylindrical inner core relative to each other.

[0022] According to another embodiment, a method for forming an RF coil for use in a plasma processing device is provided. In some embodiments, the method may begin with producing a mold comprising a cylindrical inner core and a two-piece compression sleeve, such that a first spiral groove is formed in the outer surface of the cylindrical inner core and a second spiral groove is formed in the inner surface of the two-piece compression sleeve. The method may also include winding a portion of a conductor around the cylindrical inner core so that a portion of the conductor is arranged in the first spiral groove, and applying the two-piece compression sleeve to the cylindrical inner core so that the two-piece compression sleeve surrounds the cylindrical inner core and provides a compression force to a portion of the conductor arranged in the first spiral groove and the second spiral groove to form the RF coil. The method may further include removing the two-piece compression sleeve from the cylindrical inner core and the RF coil, and removing the RF coil from the mold by rotating at least one of the RF coil or the cylindrical inner core relative to each other.

[0023] In some embodiments, applying the two-piece compression sleeve may include applying a first portion of the two-piece compression sleeve to a first side of the cylindrical inner core, and applying a second portion of the two-piece compression sleeve to a second side of the cylindrical inner core, such that the second portion and the first portion surround the cylindrical inner core and a portion of the conductor. In some embodiments, applying the two-piece compression sleeve may further include attaching the first portion to the second portion via one or more mechanical fasteners to apply a compressive force to a portion of the conductor disposed within the first spiral groove and the second spiral groove. In such embodiments, removing the two-piece compression sleeve may include removing one or more mechanical fasteners and removing the first portion and the second portion of the two-piece compression sleeve from the cylindrical inner core and the RF coil. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] A more thorough understanding of the present invention and its advantages may be obtained by referring to the following description in conjunction with the accompanying drawings, wherein like reference numerals indicate like features. It should be noted, however, that these drawings only illustrate exemplary embodiments of the disclosed concepts and are therefore not to be considered limiting of scope, as the disclosed concepts may admit to other equally effective embodiments.

[0025] Figure 1 is a perspective three-dimensional view of a mold for producing an RF coil according to an embodiment of the present disclosure;

[0026] Figure 2A flow chart showing one embodiment of a method for forming an RF coil according to the present disclosure is shown;

[0027] Figure 3 A flow chart showing another embodiment of a method for forming an RF coil according to the present disclosure; and

[0028] Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Fig. 9 ,as well as Fig.10 yes Figure 1 A three-dimensional view of the mold shown in Figure 1 shows how it can be used Figure 1 The mold shown in the figure is used to perform Figure 2 and Figure 3 The method steps shown in . DETAILED DESCRIPTION

[0029] Disclosed herein are multiple different embodiments of molds and methods for producing RF coils. More specifically, the present disclosure provides multiple different embodiments of molds and methods for producing RF coils used in plasma processing equipment. As discussed in more detail below, the disclosed mold can generally include a cylindrical inner core and a two-piece compression sleeve, the cylindrical inner core having a first spiral groove formed in the outer surface of the cylindrical inner core, and the two-piece compression sleeve having a second spiral groove formed in the inner surface of the two-piece compression sleeve. When the parts of the two-piece compression sleeve are attached together, the two-piece compression sleeve surrounds the cylindrical inner core and provides a compressive force to the conductors arranged in the first spiral groove and the second spiral groove to produce the RF coil. As discussed herein, a "cylindrical" structure is described. As used herein, "cylindrical" covers a cylindrical structure having a radius variation of 20% or less compared to a perfect cylindrical structure.

[0030] In some embodiments, each part of the mold can be produced individually using a three-dimensional (3D) printing process. By using a 3D printing process to produce the molds disclosed herein, the present disclosure provides a method for producing RF coils that is accurate, reproducible, and more time / cost effective than traditional manufacturing processes.

[0031] Figure 1 An embodiment of a mold 10 is shown that can be used to produce an RF coil for use in a plasma processing apparatus. Figure 1As shown in , the mold 10 may include a cylindrical inner core 12 and a two-piece compression sleeve, which includes a first portion 20a and a second portion 20b. The cylindrical inner core 12 may include a base plate 14 at one end thereof, and a first spiral groove 16 formed in the outer surface of the cylindrical inner core 12. The two-piece compression sleeve may include a second spiral groove 22 formed in the inner surface of the two-piece compression sleeve, and a device (e.g., an attachment guide 24 and a hole 26) for attaching the parts of the two-piece compression sleeve together. When the first portion 20a and the second portion 20b of the two-piece compression sleeve are attached together, the two-piece compression sleeve surrounds the cylindrical inner core 12 and provides a compressive force to the conductor 30 arranged in the first spiral groove 16 and the second spiral groove 22 to produce an RF coil.

[0032] like Figure 1 As shown in FIG. 1 , the two-piece compression sleeve includes a first portion 20a and a second portion 20b that can be attached to and removed from the first portion by means of one or more mechanical fasteners 28. In some embodiments, the first portion 20a can be attached to the second portion 20b (or vice versa) by inserting one or more mechanical fasteners 28 (e.g., bolts and washers) into attachment guides 24 and holes 26 formed in the two-piece compression sleeve. Figure 7 When the one or more mechanical fasteners 28 are subsequently tightened, the two-piece compression sleeve provides a compressive force to the conductor 30 to conform the conductor to the desired shape and size of the RF coil. To remove the RF coil from the mold 10, the one or more mechanical fasteners 28 can be removed from the attachment guides 24 and holes 26 so that the first part 20a can be removed from the second part 20b (or vice versa), as shown in FIG. Figure 8 As shown in .

[0033] It is noted that although specific means for attaching the first and second portions 20a, 20b of the two-piece compression sleeve together are shown and described herein (e.g., attachment guides 24, holes 26, and mechanical fasteners 28), alternative means for attachment may be used to provide the necessary compressive force to form the RF coil. For example, clamping the assembly in a vise to provide a stronger, more uniform compressive force would be one approach, or a die-type frame may be used to allow the use of parts used in a hydraulic press.

[0034] The mold 10 may generally be designed to produce an RF coil having specific features, such as shape, size, pitch, length, etc. For example, many RF coil designs are driven by physics-based RF / electromagnetic (EM) simulations that determine the optimal coil shape, size, pitch, length, etc. for a particular application. Once an RF coil design is selected for a particular application, the mold 10 may be designed and produced using the features of the RF coil design.

[0035] For example, RF coils used in plasma processing equipment are typically formed to have a height (H1) between 1 / 8 inch and 12 inches, a diameter (D1) between 1 / 8 inch and 24 inches, a number of turns between 1 and 100, and a pitch between 1 / 8 inch and 2 inches. Any of these features can be adjusted to change the electric field generated by the RF coil and the plasma generated within the plasma processing equipment. For example, the height and diameter of the RF coil can be adjusted. On the other hand, the number of turns used in the RF coil and / or the pitch between the turns can also be adjusted. Changing the size and shape of the coil will change the electric field and inductance of the coil, which in turn changes the plasma density.

[0036] To form an RF coil for use in a plasma processing apparatus, the inner core 12 of the mold 10 may be formed to have a height (H2) between 1 / 4 inch and 8 inches and a diameter (D2) between 1 / 4 inch and 24 inches. Figure 1 As shown in , the height (H2) is measured between the upper surface of the base plate 14 and the uppermost surface of the cylindrical inner core 12. The diameter (D2) is measured on the uppermost surface of the cylindrical inner core 12. In addition, the first helical groove 16 formed in the cylindrical inner core 12 and the second helical groove 22 formed in each part of the two-piece compression sleeve can each include between 1 and 100 turns. Although not shown in Figure 1 As shown in FIG. 2 , the depth of the first spiral groove 16 and the depth of the second spiral groove 22 may each be substantially equal to half the diameter of the conductor 30 .

[0037] Conductor 30 may generally be formed of substantially any conductive material. In some embodiments, conductor 30 may be a ferrous or non-ferrous metal, including but not limited to copper, aluminum, or iron.

[0038] When the two-piece compression sleeve 20 is applied to the cylindrical inner core 12 and the first and second portions 20a, 20b are attached together via mechanical fasteners (multiple) 28, the compressive force applied to the conductor 30 causes the shape and size of the conductor to conform to the first and second helical grooves 16, 22. By applying a compressive force to the conductor 30 positioned within the first and second helical grooves 16, 22, an RF coil is formed having a helical coil portion 32 and two generally straight end portions, namely a straight end portion 34 and a straight end portion 36. As described above, the shape and size of the helical coil portion 32 generally depends on the features of the mold 10 used to form the coil. In one embodiment, for example, the helical coil portion 32 can be formed to have a height (H1) between 1 / 4 inch and 8 inches, a diameter (D1) between 1 inch and 24 inches, a number of turns between 1 and 100, and a pitch between 5 / 8 inches and 2 inches.

[0039] In some embodiments, the first and second portions 20a, 20b of the two-piece compression sleeve may include additional grooves 27a and 27b, respectively, formed in the abutment surfaces 29a and 29b, respectively, to accommodate and / or support one of the generally straight end portions (e.g., 34). In other embodiments, the additional grooves may be omitted, such as where the base plate 14 is removed and the generally straight end portion 34 is made to extend in the opposite direction.

[0040] In some embodiments, the two-piece compression sleeve may include an overmolded portion and a drag portion that help form a negative shape of the part and help form the part into a desired shape (e.g., cavity diameter, coil outer diameter, and coil pitch, etc.). The compression sleeve prevents uneven surfaces and warped geometry (e.g., deformed coil shape) of the RF coil when compressive forces are applied to the conductor 30.

[0041] As described above, RF coils are typically manufactured by external suppliers who produce the RF coils through a combination of processing, bending, and winding machinery. Unfortunately, the manufacturing methods used by most external suppliers lack accuracy and tend to produce uneven surfaces and warped geometries (e.g., deformed coil shapes), which may affect the near-field behavior of the RF coil. In addition, many external suppliers have long lead times (e.g., about 4 to 6 weeks), which can significantly increase the design time, especially when multiple iterations are required to perfect the RF coil design.

[0042] To overcome these problems, Figure 1The mold 10 shown in is preferably formed using a three-dimensional (3D) printing process. 3D printing is an additive manufacturing process that uses computer-aided design (CAD) software to guide hardware to deposit materials layer by layer in a precise geometric shape, and can be used to quickly, accurately, and cost-effectively manufacture 3D objects. Typically, each part of the mold 10 (e.g., the cylindrical inner core 12, the first part 20a and the second part 20b of the two-piece compression sleeve) can be produced separately using a 3D printer.

[0043] In some embodiments, each part of the mold 10 can be produced by instructing the 3D printer to deposit the thermoplastic polymer material layer by layer until the cylindrical inner core 12, the first part 20a and the second part 20b are formed to the desired specifications. Although essentially any thermoplastic polymer material can be used in the 3D printing process, in at least some embodiments, a thermoplastic polymer material having a glass transition temperature (Tg) above 100°C and a compressive strength above 200 MPa may be preferred. In one embodiment, a carbon fiber polycarbonate material having a Tg of about 147°C and a compressive strength of about 320 MPa can be used to form the cylindrical inner core 12 of the mold 10, the first part 20a and the second part 20b of the two-piece compression sleeve.

[0044] During the design phase, the mold 10 was initially constructed using polylactic acid or polylactide (PLA), which has a much lower Tg (about 55°C to 60°C) and compressive strength (about 94MPa) than carbon fiber polycarbonate. When the PLA mold is subsequently used to form the RF coil, the PLA mold is likely to deform near the RF coil area due to the heat generated during the coil forming process or the compressive force required to form the coil. It was subsequently discovered that by using a carbon fiber polycarbonate material instead of PLA, the mold was able to withstand higher compressive forces and temperatures, thereby avoiding the deformation experienced by the PLA mold. Although carbon fiber polycarbonate has been shown to produce a successful mold 10, and therefore a successful RF coil, other thermoplastic polymer materials with suitable glass transition temperatures and compressive strengths may also be used to form the mold. For example, suitable thermoplastic polymer materials may include a wide variety of materials, including but not limited to Kyron and MAX-XS.

[0045] It is noted that although the successful mold 10 is simplified to be implemented by 3D printing a thermoplastic polymer material to have a desired shape, form, and size, other materials can also be used to form the mold. For example, the mold 10 can alternatively be formed of 3D printed metal (such as but not limited to aluminum, stainless steel, or Inconel).

[0046] Figures 2 to 10 Demonstrated the use of Figure 1An exemplary method of forming an RF coil using the mold 10 shown in FIG. 1 and described above. In particular, Figure 2 and Figure 3 is a flow chart illustrating example embodiments of methods 100 and 200 that may be used to form an RF coil according to the present disclosure. Figures 4 to 10 Shows how to use Figure 1 The mold 10 shown in FIG. Figure 2 and Figure 3 Although the method steps shown in Figure 1 The mold 10 shown in FIG. Figure 2 and Figure 3 The methods 100 and 200 shown in FIG. 1 are used to form RF coils for use within a plasma processing apparatus, but it should be noted that similar molds and / or similar methods may be used to form RF coils for other uses and applications.

[0047] It will be recognized that Figures 4 to 10 The embodiments are merely exemplary, and other methods may also use the techniques described herein. Further, additional steps may be added to Figures 4 to 10 In the method shown, the steps described are not intended to be exclusive. In addition, the order of the steps is not limited to the order shown in the figures, because different orders may occur and / or various steps may be performed in combination or simultaneously.

[0048] Figure 2 An exemplary method 100 for forming an RF coil for use in a plasma processing apparatus is presented. In some embodiments, Figure 2 The method 100 shown in the figure may begin (at step 110) using a 3D printing process to produce a mold, the mold comprising a cylindrical inner core and a two-piece compression sleeve, wherein a first helical groove is formed in an outer surface of the cylindrical inner core and a second helical groove is formed in an inner surface of the two-piece compression sleeve. Although not strictly limited to this, Figure 1 One embodiment of a mold 10 is shown that may be produced using a 3D printing process to include the above-described structures.

[0049] In some embodiments, the producing the mold using a 3D printing process (at step 110) includes producing the cylindrical inner core 12, the first portion 20a of the two-piece compression sleeve, and the second portion 20b of the two-piece compression sleeve separately using a thermoplastic polymer material having a glass transition temperature of more than 100° C. and a compressive strength of more than 200 MPa using a 3D printing process. As described above, various thermoplastic polymer materials may be used.

[0050] In some embodiments, the use of a 3D printing process to produce a mold (at step 110) includes producing a cylindrical inner core 12 having a height between 1 / 4 inch and 8 inches and a diameter between 1 inch and 24 inches, and producing the first and second spiral grooves 16 / 22 having a number of turns between 1 and 100 and a pitch between 5 / 8 inch and 2 inches. As described above, a mold 10 having such a shape and size may be suitable for forming an RF coil for use in a plasma processing device. In other embodiments, a mold produced using a 3D printing process may be used to form an RF coil suitable for other uses and applications.

[0051] At step 120, method 100 includes wrapping a portion of the conductor around the cylindrical inner core such that the portion of the conductor is disposed within the first helical groove. Figure 4 As shown in , for example, a portion of the conductor 30 (eg, the coil portion 32 ) may be wrapped around the cylindrical inner core 12 (at step 120 ) such that a portion of the conductor is disposed within the first helical groove.

[0052] At step 130, the method 100 includes applying a two-piece compression sleeve to the cylindrical inner core such that the two-piece compression sleeve surrounds the cylindrical inner core and provides a compressive force to a portion of the conductor disposed within the first helical groove and the second helical groove to form the RF coil. In some embodiments, applying the two-piece compression sleeve (at step 130) may include applying a first portion 20a of the two-piece compression sleeve to a first side (e.g., Figure 5 ), and applying the second portion 20b of the two-piece compression sleeve to the second side of the cylindrical core (as shown in FIG. Figure 6 ), such that the second portion 20b and the first portion 20a surround the cylindrical inner core 12 and a portion of the conductor 30 (e.g., the coil portion 32). In some embodiments, applying the two-piece compression sleeve (at step 130) may further include attaching the first portion 20a to the second portion 20b via one or more mechanical fasteners 28 to apply a compressive force (e.g., Figure 7 shown in ).

[0053] In some embodiments (not shown), the method 100 may further include removing one or more mechanical fasteners 28 (e.g. Figure 8 ), remove the first and second portions 20a, 20b of the two-piece compression sleeve from the cylindrical inner core 12 and the RF coil (as shown in FIG. Figure 8 and Fig. 9), and removing the RF coil from the mold by rotating at least one of the RF coil or the cylindrical inner core 12 relative to each other (as shown in Fig.10 shown in ).

[0054] Figure 3 An exemplary method 200 for forming an RF coil for use in a plasma processing apparatus is presented. In some embodiments, Figure 3 The method 200 shown in FIG. 2 may begin by producing (at step 210) a mold comprising a cylindrical inner core and a two-piece compression sleeve such that a first spiral groove is formed in an outer surface of the cylindrical inner core and a second spiral groove is formed in an inner surface of the two-piece compression sleeve. In some embodiments, the mold may be produced (at step 210) using a 3D printing process, as described above. However, it is noted that method step 210 is not strictly limited to a 3D printing process and may be performed using other suitable processes.

[0055] At step 220, method 200 includes wrapping a portion of the conductor around the cylindrical inner core such that the portion of the conductor is disposed within the first helical groove. Figure 4 As shown in , for example, a portion of the conductor 30 (eg, the coil portion 32) may be wrapped around the cylindrical inner core 12 (at step 220) such that a portion of the conductor is disposed within the first helical groove.

[0056] At step 230, the method 200 includes applying a two-piece compression sleeve to the cylindrical inner core such that the two-piece compression sleeve completely surrounds the cylindrical inner core and provides a compressive force to a portion of the conductor disposed within the first helical groove and the second helical groove to form the RF coil. In some embodiments, applying the two-piece compression sleeve (at step 230) may include applying a first portion 20a of the two-piece compression sleeve to a first side (e.g., Figure 5 ), and applying the second portion 20b of the two-piece compression sleeve to the second side of the cylindrical core (as shown in FIG. Figure 6 ), such that the second portion 20b and the first portion 20a surround the cylindrical inner core 12 and a portion of the conductor 30 (e.g., the coil portion 32). In some embodiments, applying the two-piece compression sleeve (at step 230) may further include attaching the first portion 20a to the second portion 20b via one or more mechanical fasteners 28 to apply a compressive force (e.g., Figure 7 shown in ).

[0057] At step 240, the method 200 includes removing the two-piece compression sleeve from the cylindrical inner core and the RF coil. In some embodiments, for example, the two-piece compression sleeve can be removed from the cylindrical inner core 12 and the RF coil by removing one or more mechanical fasteners 28 (e.g., at step 240, Figure 8 ), then removing the first and second portions 20a, 20b of the two-piece compression sleeve from the cylindrical inner core 12 and the RF coil (as shown in FIG. Figure 8 and Fig. 9 shown in ).

[0058] At step 250, method 200 includes removing the RF coil from the mold by rotating at least one of the RF coil or the cylindrical core relative to each other. Fig.10 As shown in , for example, the RF coil may be removed from the mold 10 (at step 250 ) by rotating the RF coil relative to the cylindrical inner core 12 (or vice versa).

[0059] In view of this description, further modifications and alternative embodiments of the present invention will be apparent to those skilled in the art. Therefore, this description will be construed as being illustrative only and is intended to teach those skilled in the art how to implement the present invention. It should be understood that the forms and methods of the present invention shown and described herein will be considered as currently preferred embodiments. Equivalent technologies may replace the technologies shown and described herein, and certain features of the present invention may be utilized independently of the use of other features, all of which will be apparent to those skilled in the art who benefit from the description of the present invention.

Claims

1. A mold for producing a radio frequency (RF) coil for use in a plasma processing apparatus, the mold comprising: a cylindrical inner core having a first spiral groove formed in an outer surface of the cylindrical inner core; as well as A two-piece compression sleeve having a second helical groove formed in an inner surface of the two-piece compression sleeve, wherein when portions of the two-piece compression sleeve are attached together, the two-piece compression sleeve is configured to surround the cylindrical inner core and provide a compressive force to the conductors arranged in the first helical groove and the second helical groove to produce the RF coil.

2. The mold according to claim 1, wherein The two-piece compression sleeve includes a first portion and a second portion removably attached to the first portion by one or more mechanical fasteners.

3. The mold according to claim 1, wherein The two-piece compression sleeve includes an upper compression sleeve and a lower compression sleeve that help form a desired negative shape of the RF coil.

4. The mold according to claim 1, wherein: The cylindrical inner core includes a height between 5 / 8 inches and 8 inches and a diameter between 1 inch and 24 inches.

5. The mold according to claim 1, wherein The first spiral groove and the second spiral groove each include between 1 and 100 turns and a pitch between 5 / 8 inches and 2 inches.

6. The mold according to claim 1, wherein: The cylindrical inner core and the two-piece compression sleeve are produced by three-dimensional (3D) printing of a thermoplastic polymer material having a glass transition temperature above 100° C. and a compressive strength above 200 MPa.

7. The mold according to claim 1, wherein: The conductor comprises copper or aluminum.

8. A method for forming a radio frequency (RF) coil for use in a plasma processing apparatus, the method comprising: producing a mold using a three-dimensional (3D) printing process, the mold comprising a cylindrical inner core and a two-piece compression sleeve, wherein a first helical groove is formed in an outer surface of the cylindrical inner core and a second helical groove is formed in an inner surface of the two-piece compression sleeve; winding a portion of a conductor around the cylindrical inner core such that a portion of the conductor is disposed within the first helical groove; and The two-piece compression sleeve is applied to the cylindrical inner core such that the two-piece compression sleeve surrounds the cylindrical inner core and provides a compressive force to a portion of the conductor disposed within the first helical groove and the second helical groove to form the RF coil.

9. The method of claim 8, further comprising: removing the two-piece compression sleeve from the cylindrical inner core and the RF coil; as well as The RF coil is removed from the mold by rotating at least one of the RF coil or the cylindrical core relative to each other.

10. The method of claim 8, wherein: The applying the two-piece compression sleeve to the cylindrical inner core comprises: applying a first portion of the two-piece compression sleeve to a first side of the cylindrical core; applying a second portion of the two-piece compression sleeve to a second side of the cylindrical inner core such that the second portion and the first portion surround the cylindrical inner core and a portion of the conductor; and The first portion is attached to the second portion by one or more mechanical fasteners to apply a compressive force to a portion of the conductor disposed within the first and second helical grooves.

11. The method of claim 10, further comprising: removing the one or more mechanical fasteners; removing the first portion and the second portion of the two-piece compression sleeve from the cylindrical inner core and the RF coil; as well as The RF coil is removed from the mold by rotating at least one of the RF coil or the cylindrical core relative to each other.

12. The method of claim 8, wherein: The use of a three-dimensional (3D) printing process to produce the mold includes: The cylindrical inner core, the first portion of the two-piece compression sleeve, and the second portion of the two-piece compression sleeve are individually produced using the 3D printing process using a thermoplastic polymer material having a glass transition temperature above 100° C. and a compressive strength above 200 MPa.

13. The method of claim 8, wherein: The use of the three-dimensional (3D) printing process to produce the mold includes: The cylindrical core is produced to have a height between 5 / 8 inch and 8 inches and a diameter between 1 inch and 24 inches.

14. The method of claim 8, wherein: The use of the three-dimensional (3D) printing process to produce the mold includes: The first spiral groove and the second spiral groove are produced to have between 1 and 100 turns and between 5 / 8 inch and 2 inches in pitch.

15. A method for forming a radio frequency (RF) coil for use in a plasma processing apparatus, the method comprising: producing a mold by a three-dimensional (3D) printing process, the mold comprising a cylindrical inner core and a two-piece compression sleeve such that a first helical groove is formed in an outer surface of the cylindrical inner core and a second helical groove is formed in an inner surface of the two-piece compression sleeve; winding a portion of a conductor around the cylindrical inner core such that a portion of the conductor is disposed within the first spiral groove; applying the two-piece compression sleeve to the cylindrical inner core such that the two-piece compression sleeve surrounds the cylindrical inner core and provides a compressive force to a portion of the conductor disposed within the first helical groove and the second helical groove to form the RF coil; removing the two-piece compression sleeve from the cylindrical inner core and the RF coil; as well as The RF coil is removed from the mold by rotating at least one of the RF coil or the cylindrical core relative to each other.

16. The method of claim 15, wherein: The applying the two-piece compression sleeve to the cylindrical inner core comprises: applying a first portion of the two-piece compression sleeve to a first side of the cylindrical core; applying a second portion of the two-piece compression sleeve to a second side of the cylindrical inner core such that the second portion and the first portion surround the cylindrical inner core and a portion of the conductor; and The first portion is attached to the second portion by one or more mechanical fasteners to apply a compressive force to a portion of the conductor disposed within the first and second helical grooves.

17. The method of claim 16, wherein: Removing the two-piece compression sleeve includes: removing the one or more mechanical fasteners; and The first and second portions of the two-piece compression sleeve are removed from the cylindrical core and the RF coil.

18. The method of claim 15, wherein: The production of the mold includes using a thermoplastic polymer material having a glass transition temperature of more than 100° C. and a compressive strength of more than 200 MPa.

19. The method of claim 15, wherein: Producing the mold includes producing the cylindrical core to have a height between 5 / 8 inches and 8 inches and a diameter between 1 inch and 24 inches.

20. The method of claim 15, wherein: The manufacturing of the mold includes manufacturing the first spiral groove and the second spiral groove to have a number of turns between 1 and 100 and a pitch between 5 / 8 inches and 2 inches.

Images