Parallel resonant antenna for radial plasma control.

Abstract

According to one embodiment, a radiating structure of a resonant structure used for plasma processing is disclosed. The radiating structure includes a set of first arms and a set of second arms. Each first arm has a first inductance and is coupled to a respective first capacitor and a respective second capacitor of the resonant structure to form a corresponding first resonant circuit operating at a first resonant frequency. Each second arm has a second inductance and is coupled to a respective third capacitor and a respective fourth capacitor of the resonant structure to form a corresponding second resonant circuit operating at a second resonant frequency. In a first operating mode, the resonant structure operates as a single resonant antenna. In a second operating mode, the resonant structure operates as a parallel resonant antenna.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Non-Provisional Patent Application No. 17 / 985,360, filed November 11, 2022, which is incorporated herein by reference in its entirety.

[0002] FIELD OF THE DISCLOSURE The present disclosure relates generally to semiconductor processing technology and, in particular embodiments, to an apparatus for emitting electromagnetic waves within a plasma processing system. [Background technology]

[0003] Plasma processing is widely used in the manufacturing and fabrication of high density microcircuits in the semiconductor industry.

[0004] In a plasma processing system, electromagnetic waves radiated into a plasma chamber generate an electromagnetic field that heats electrons within the chamber, igniting a plasma that treats substrates in processes such as etching, deposition, oxidation, and sputtering. Summary of the Invention [Problem to be solved by the invention]

[0005] Non-uniform electromagnetic fields within a plasma processing chamber result in non-uniform processing of the substrate because different portions of the substrate are processed with plasma of varying densities. Therefore, an apparatus and system that improves the uniformity and radial distribution (i.e., center-to-edge or edge-to-center) control of the electromagnetic field in a plasma processing system is desirable. [Means for solving the problem]

[0006] Technical advantages are generally achieved by embodiments of the present disclosure, which describe an apparatus for emitting electromagnetic waves in a plasma processing system.

[0007] A first aspect relates to a radiating structure of a resonant structure used for plasma processing. The radiating structure includes a set of first arms and a set of second arms. Each first arm has a first inductance and is coupled to a respective first capacitor and a respective second capacitor of the resonant structure to form a corresponding first resonant circuit operating at a first resonant frequency. Each second arm has a second inductance and is coupled to a respective third capacitor and a respective fourth capacitor of the resonant structure to form a corresponding second resonant circuit operating at a second resonant frequency. In a first operating mode, the resonant structure operates as a single resonant antenna. In a second operating mode, the resonant structure operates as a parallel resonant antenna.

[0008] Thus, in a first implementation of the radiating structure according to the first aspect, each first arm has the same first length and each second arm has a second length different from the first length.

[0009] As such, in the second implementation of the radiating structure according to the first aspect, or any of the previous implementations of the first aspect, each of the first and second arms is a spiral.

[0010] As such, in the third implementation of the radiating structure according to the first aspect, or any of the preceding implementations of the first aspect, each first and each second arm is Archimedean, logarithmic, Fibonacci, an involute of a circle, or a linear spiral.

[0011] Thus, in a fourth implementation of the radiating structure according to the first aspect, or any of the previous implementations of the first aspect, the radiating structure further includes an inner ring and an outer ring. The diameter of the inner ring is smaller than the diameter of the outer ring. The inner and outer rings have the same center point. Each of the first and second arms has a first end point coupled to the inner ring. Each of the first arms has a second end point coupled to the outer ring. Each of the second arms has a second end point mechanically decoupled from the outer ring.

[0012] As such, in the fifth implementation of the radiating structure according to the first aspect, or any of the preceding implementations of the first aspect, each first capacitor and each third capacitor are the same capacitor coupled to the inner ring via a first conductive offset, each second capacitor is coupled to the outer ring via a second conductive offset, and each fourth capacitor is coupled to the second end of each second arm via a third conductive offset.

[0013] Thus, in a sixth implementation of the radiating structure according to the first aspect, or any of the preceding implementations of the first aspect, the radiating structure further includes inner and outer rings. The diameter of the inner ring is smaller than the diameter of the outer ring. The inner and outer rings have the same center point. Each of the first and second arms has a first end point coupled to the outer ring. Each of the first arms has a second end point coupled to the inner ring. Each of the second arms has a second end point mechanically decoupled from the inner ring.

[0014] As such, in the seventh implementation of the radiating structure according to the first aspect, or any of the preceding implementations of the first aspect, each first capacitor and each third capacitor is the same capacitor that is coupled to the outer ring via a first conductive offset, each second capacitor is coupled to the inner ring via a second conductive offset, and each fourth capacitor is coupled to the second end point of each second arm via a third conductive offset.

[0015] Thus, in an eighth implementation of the radiating structure according to the first aspect, or any of the preceding implementations of the first aspect, each first and each second arm has the same length. Each first capacitor is coupled to a first end of each first arm via a first conductive offset. Each second capacitor is coupled to a second end of each first arm via a second conductive offset. Each third capacitor is coupled to a first end of each second arm via a third conductive offset. Each fourth capacitor is coupled to a second end of each second arm via a fourth conductive offset.

[0016] Thus, in the ninth implementation of the radiating structure according to the first aspect, or any preceding implementation of the first aspect, each respective first capacitor is coupled to every other respective first capacitor, each respective second capacitor is coupled to every other respective second capacitor, each respective third capacitor is coupled to every other respective third capacitor, and each respective fourth capacitor is coupled to every other respective fourth capacitor.

[0017] Thus, in a tenth implementation of the radiating structure according to the first aspect, or any of the preceding implementations of the first aspect, the radiating structure further includes an inner ring and an outer ring. The diameter of the inner ring is smaller than the diameter of the outer ring. The inner and outer rings have the same center point. Each of the first and second arms has a first end point coupled to the inner ring. Each of the first and second arms has a second end point coupled to the outer ring.

[0018] Thus, in an eleventh implementation of the radiating structure according to the first aspect, or any of the preceding implementations of the first aspect, in the second operating mode, the density profile of the plasma generated by the resonant structure is controlled radially by adjusting the RF waveform corresponding to each resonant circuit.

[0019] A second aspect relates to a radiating structure of a resonant structure used for plasma processing. The radiating structure includes a first set of arms and a second set of arms. The first set of arms are coupled at a first end to a first capacitive plate of the resonant structure and at a second end to a second capacitive plate of the resonant structure to form a first set of resonant circuits operating at a first resonant frequency. The second set of arms are coupled at a first end to the first capacitive plate of the resonant structure and at a second end to a third capacitive plate of the resonant structure to form a second set of resonant circuits operating at a second resonant frequency. In a first operating mode, the resonant structure operates as a single resonant antenna. In a second operating mode, the resonant structure operates as a parallel resonant antenna.

[0020] Thus, in a first implementation of the radiating structure according to the second aspect, in a second operating mode, the density profile of the plasma generated by the resonant structure is controlled radially by adjusting the RF waveforms corresponding to the first resonant frequency and the second resonant frequency.

[0021] In such a second implementation of the radiating structure according to the second aspect, or any of the preceding implementations of the second aspect, the first capacitive plate is formed by the first conductive plate, the first dielectric, and the bottom surface of the housing of the resonant structure, the second capacitive plate is formed by the second conductive plate, the second dielectric, and the bottom surface of the housing of the resonant structure, and the third capacitive plate is formed by the third conductive plate, the third dielectric, and the bottom surface of the resonant structure.

[0022] As such, in the third implementation of the radiating structure according to the second aspect, or any of the previous implementations of the second aspect, the first set of arms and the second set of arms are arranged in a repeating radial pattern.

[0023] Thus, in the fourth implementation of the radiating structure according to the second aspect, or any of the previous implementations of the second aspect, each first arm has the same first length and each second arm has the same second length that is different from the first length.

[0024] A third aspect relates to a resonant structure for plasma processing. The resonant structure includes first, second, third, and fourth capacitive plates; a first set of arms coupled at a first end to the first capacitive plate and at a second end to the second capacitive plate to form a first set of resonant circuits operating at a first resonant frequency; and a second set of arms coupled at a first end to the third capacitive plate and at a second end to the fourth capacitive plate to form a second set of resonant circuits operating at a second resonant frequency. In a first operating mode, the resonant structure operates as a single resonant antenna. In a second operating mode, the resonant structure operates as a parallel resonant antenna.

[0025] Thus, in the first embodiment of the resonant structure according to the third aspect, in the second operating mode, the density profile of the plasma generated by the resonant structure is controlled radially by adjusting the RF waveforms corresponding to the first resonant frequency and the second resonant frequency.

[0026] As such, in the second embodiment of the resonant structure according to the third aspect, or any of the aforementioned implementations of the third aspect, the first capacitive plate is formed by a first conductive plate, a first dielectric, and a bottom surface of the housing of the resonant structure, the second capacitive plate is formed by a second conductive plate, a second dielectric, and a bottom surface of the housing of the resonant structure, the third capacitive plate is formed by a third conductive plate, a third dielectric, and a bottom surface of the resonant structure, and the fourth capacitive plate is formed by a fourth conductive plate, a fourth dielectric, and a bottom surface of the resonant structure.

[0027] Thus, in the third implementation of the resonant structure according to the third aspect, or any of the preceding implementations of the third aspect, each first and each second arm is an Archimedean spiral, each first arm having the same first length, and each second arm having the same second length that is different from the first length.

[0028] Thus in the fourth implementation of the resonant structure according to the third aspect, or any of the preceding implementations of the third aspect, each first and each second arm is an Archimedean spiral, and each first arm and each second arm have the same length.

[0029] The embodiments can be implemented in hardware, software, or any combination thereof.

[0030] For a more complete understanding of the present disclosure and its advantages, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a diagram of an embodiment of a plasma processing system. [Figure 2A] 1 is a schematic diagram of a hybrid of a resonant structure according to one embodiment. [Figure 2B] 2B is a cross-sectional view AA of the resonant structure of the embodiment of FIG. 2A. [Figure 2C] 2B is a cross-sectional view of the resonant structure of the embodiment of FIG. 2A; [Figure 2D] 2B is a diagram of a resonant region corresponding to one or more modes of the resonant structure of the embodiment of FIG. 2A. [Figure 3A] 1 is a schematic diagram of a hybrid of a resonant structure according to one embodiment. [Figure 3B] 3B is a diagram of a resonant region corresponding to one or more modes of the resonant structure of the embodiment of FIG. 3A. [Figure 4] 1 is a schematic diagram of a hybrid of a resonant structure according to one embodiment. [Figure 5A]FIG. 1B is a diagram of a first conductive plate of one embodiment of a capacitive outer ring of a resonant structure. [Figure 5B] FIG. 10 is a diagram of a second conductive plate of one embodiment of a capacitive outer ring of a resonant structure. [Figure 5C] FIG. 10 is a diagram of a segmented outer ring of one embodiment of a capacitive outer of a resonant structure. [Figure 6A] FIG. 2 is a diagram of a first dielectric plate of one embodiment of an insulating structure of a resonant structure. [Figure 6B] FIG. 10 is a diagram of a second dielectric plate of one embodiment of the insulating structure of the resonant structure. [Figure 6C] FIG. 10 is a diagram of a shared dielectric plate of one embodiment of an insulating structure of a resonant structure. DETAILED DESCRIPTION OF THE INVENTION

[0032] The present disclosure provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. Specific embodiments are merely illustrative of particular configurations and do not limit the scope of the claimed embodiments. Features from different embodiments may be combined to form further embodiments, unless otherwise specified.

[0033] Variations or modifications described with respect to one of the embodiments may also be applied to the other embodiments. Furthermore, it should be understood that various changes, substitutions, and alterations can be made herein without departing from the spirit and scope of the present disclosure as defined by the appended claims.

[0034] Although aspects of the present invention are described primarily in the context of processing substrates, aspects of the present invention may be applied to fields outside the semiconductor industry as well. Plasma can be used to treat and modify surface properties through functionalization. For example, to prepare a surface for paint deposition, plasma can convert a hydrophobic surface to a hydrophilic surface. Furthermore, aspects of the present invention are not limited to plasma. For example, RF can be used to thaw frozen foods or to dry textiles, food, wood, etc. In these various examples and across industries, controlling the radial distribution of an oscillating magnetic field as disclosed herein is advantageous.

[0035] In various embodiments, reference to a magnetic field refers to a magnetic field oscillating at some frequency, for example, one of an RF frequency or a microwave frequency, and in these embodiments, the magnetic field does not refer to a DC magnetic field.

[0036] In embodiments, an antenna is proposed that enables radial distribution control of plasma for semiconductor plasma processing and provides a controlled center-to-edge variation in plasma density profile. In one mode of operation, the antenna is configured to simultaneously resonate with multiple resonance zones at different resonance frequencies. In a second mode of operation, the antenna is configured to resonate with a single resonance zone at a single resonance frequency. In a third mode of operation, the antenna is configured to resonate with a single resonance frequency but with multiple resonance zones. Other configurations are contemplated, as detailed below.

[0037] In various embodiments, a radiating structure is proposed having multiple spiral arms. The arms form a resonant circuit with the capacitor of the resonant structure to which the radiating structure belongs. The resonant circuits can be grouped into sets, and within each set, the resonant circuits can have the same resonant frequency. In embodiments, the arms in each set are equal but different from the arms in other sets. In other embodiments, the arms are similar to the arms in other sets. In such embodiments, the resonant structure capacitors provide resonant circuit variation that distinguishes the resonance of each set. In embodiments, the arms are spiral arms. In other embodiments, the arms are straight (i.e., radial). These and further details are discussed in more detail below.

[0038] Figure 1 shows a diagram of one embodiment of a plasma processing system 100. The plasma processing system 100 includes an RF source 102, a resonant structure 104, a plasma chamber 106, and an optional dielectric plate 114, which may (or may not) be arranged as shown in Figure 1. Additionally, the plasma processing system 100 may include additional components not depicted in Figure 1.

[0039] In an embodiment, the RF source 102 includes an RF power supply, which may include a generator circuit and a matching circuit (not shown). The RF source 102 is coupled to the resonant structure 104 via a power transmission line, such as a coaxial cable. The RF source supplies a forward RF wave to the resonant structure 104. The resonant structure 104 includes one or more radiating structures. The forward RF wave travels through the resonant structure 104 and is transmitted (i.e., radiated) toward the plasma chamber 106.

[0040] The plasma chamber 106 includes a substrate holder 108. As shown, a substrate 110 is placed on the substrate holder 108 for processing. Optionally, the plasma chamber 106 may include a bias power supply 118 coupled to the substrate holder 108. The plasma chamber 106 may also include one or more pump outlets 116 that remove by-products from the plasma chamber 106 through selective control of gas flow rates therein. In embodiments, the pump outlets 116 are located near (e.g., below / around) the substrate holder 108 and the substrate 110. In embodiments, the plasma chamber 106 may include additional substrate holders (not shown). In embodiments, the arrangement of the substrate holders 108 may differ from that shown in FIG. 1 . Thus, the quantity and location of the substrate holders 108 are not limiting.

[0041] In an embodiment, the resonant structure 104 is separated from the plasma chamber 106 by a dielectric plate 114, typically made of a dielectric material. The dielectric plate 114 separates the low-pressure environment inside the plasma chamber 106 from the outside atmosphere. It should be appreciated that the resonant structure 104 can be mounted directly adjacent to the plasma chamber 106, or the resonant structure 104 can be separated from the plasma chamber 106 by air. In an embodiment, the dielectric plate 114 is selected to minimize reflection of RF waves from the plasma chamber 106. In another embodiment, the resonant structure 104 is embedded within the dielectric plate 114.

[0042] In an embodiment, the resonant structure 104 radiates an electromagnetic field toward the plasma chamber 106. The radiated electromagnetic field generates an azimuthally symmetric, high-density plasma 112 with a low capacitively coupled electric field.

[0043] In embodiments, the resonant structure 104 includes arms connected to capacitive structures that create azimuthal symmetry, as disclosed herein. In embodiments, the excitation frequency of the resonant structure 104 is in the radio frequency range (10-400 MHz), although this is not intended to be limiting and other frequency ranges are contemplated as well. For example, aspects of the invention disclosed herein apply equally well to applications in the microwave frequency range.

[0044] In an embodiment, the resonant structure 104 includes a resonant element, which may be an arm electrically connected to a capacitive structure of the resonant structure 104. The arm and the capacitive structure resonate with the electromagnetic waves provided by the RF source 102.

[0045] In an embodiment, the resonating element supports a standing electromagnetic wave. The standing electromagnetic wave has regions of high electric field and other regions of high magnetic field. The regions of high magnetic field are composed of conductive paths. The resonating element is mounted close to and parallel to the dielectric plate 114 so that the oscillating magnetic field from the resonating element penetrates into the plasma chamber 106. The time-varying magnetic field induces a time-varying electric field, which transfers energy to the plasma electrons.

[0046] In an embodiment, the resonant structure 104 includes a region where the electric field is high (i.e., located away from the dielectric plate 114). In an embodiment, such region is composed of a metal structure having a flat surface. In an embodiment, the flat surfaces of two metal pieces face each other and are separated by a dielectric. The volume between the two metal pieces, occupied by the dielectric, is a location of high electric field in each resonant circuit of the resonant structure 104.

[0047] In other embodiments, the metal piece may have a cylindrical or other shape. In either case, the two metal surfaces are separated by a region filled with a dielectric, which may be air or a vacuum.

[0048] The magnetic field in high field elements is due to the current flowing along those elements. The electric field in high field elements is due to the presence of electric charges. Elements with high field are connected to other such elements through the elements with high field such that electric charges flow by the current from one region of high field to another region of high field, thereby generating a magnetic field within the high field elements.

[0049] In one embodiment, the high field elements may also be connected so that the electric fields within the resonant structure 104 are in phase and have the same amplitude, although this feature is non-limiting.

[0050] In an embodiment, all of the high magnetic field elements and high electric field elements are substantially identical to one another.

[0051] In an embodiment, the elements of the resonant structure 104 are arranged about a central axis of symmetry. In one embodiment, the central axis of symmetry is perpendicular to the dielectric plate 114. In one embodiment, where the dielectric plate 114 is disk-shaped, the central axis of symmetry passes through the center of the disk.

[0052] In an embodiment, an RF source 102 couples energy to an interface of the resonant structure 104 to generate a standing electromagnetic wave from the resonant structure 104. The RF source 102 is coupled to the interface via a transmission line in an embodiment. The interface desirably maintains the same or greater symmetry under rotation about an axis of symmetry than the elements of the resonant structure 104.

[0053] In embodiments, the interface couples energy to portions of the resonant structure 104 where the electric field is highly capacitively coupled. In embodiments, the interface couples energy to portions of the resonant structure 104 where the magnetic field is highly inductively coupled. In either case, the interface can be positioned such that the electromagnetic field generated by the resonant structure 104 penetrates into the plasma chamber 106 and may itself thereby generate a plasma 112.

[0054] In one embodiment, the resonant structure 104 couples RF power from the RF source 102 into the plasma chamber 106 to process the substrate 110. In particular, the resonant structure 104 emits electromagnetic waves in response to a forward RF wave being supplied from the RF source 102. The emitted electromagnetic waves enter the plasma chamber 106 from the atmosphere side (i.e., the resonant structure 104 side) of the dielectric plate 114. The emitted electromagnetic waves generate an electromagnetic field within the plasma chamber 106. The generated electromagnetic field ignites and sustains a plasma 112 by transferring energy to free electrons within the plasma chamber 106. The plasma 112 can be used, for example, to selectively etch or deposit material on the substrate 110.

[0055] 1, the resonant structure 104 is external to the plasma chamber 106. However, in embodiments, the resonant structure 104 can be mounted inside the plasma chamber 106.

[0056] In an embodiment, the operating frequency of the resonant structure 104 is between 5 and 100 megahertz (MHz). In an embodiment, the power delivered by the resonant structure 104 is in the range of 10 to 5000 watts (W), and is determined by various factors such as the distance from the resonant structure 104, the impedance value, etc.

[0057] Figure 2A shows a hybrid schematic of an embodiment of a resonant structure 200. Figure 2B shows a cross-sectional view of the resonant structure taken along line AA. Figure 2C shows a cross-sectional view of the resonant structure taken along line BB.

[0058] 2A, an exemplary radiating structure 221 of an embodiment of resonant structure 200 is shown. Other portions of resonant structure 200 that provide RF power to radiating structure 221 are shown in schematic form.

[0059] The radiating structure 221 may also be referred to as an antenna plate or a radiating element. The radiating structure 221 is shown as a single, conductive, planar, ring-shaped, monolithic structure. The radiating structure 221 includes an inner ring 223, an outer ring 225, a set of first arms 222a, and a set of second arms 222b. Each arm 222a-b has n-fold symmetry about an axis passing through the center point of the radiating structure 221.

[0060] In the radiating structure, each arm of the first set of arms 222a and the second set of arms 222b is shown as a helical arm, although the helical shape of the arms is not limiting. For example, in one embodiment, the arms can be radial arms with no curvature (e.g., straight). In embodiments in which the arms are in a helical form, the helix can be, but is not limited to, an Archimedean, logarithmic, Fibonacci, or an involute of a circular spiral.

[0061] Radiating structure 221 is shown as a solid conductive plate with cutouts that form arms 222a-b. However, it should be appreciated that the unitary design of radiating structure 221 is non-limiting, and structures formed by individual components, such as inner ring 223, outer ring 225, and sets of first and second arms 222a-b, are contemplated in other embodiments. Furthermore, it should be appreciated that in embodiments, radiating structure 221 can include multiple wires arranged in a helical configuration. In these embodiments, each wire is connected at one end to the inner ring and at the other end to the outer ring.

[0062] In an embodiment, the radiating structure 221 is formed by the set of first and second arms 222a-b without the inner ring 223 or the outer ring 225. In another embodiment, the radiating structure 221 is formed by the set of first and second arms 222a-b and only one of the inner ring 223 or the outer ring 225.

[0063] In an embodiment, arms 222a-b are formed using, for example, copper tubing. In an embodiment, arms 222a-b are formed by individually machined pieces made from, for example, aluminum.

[0064] In an embodiment, the radiating structure 221 is a conductive plate with multiple axially symmetric spiral cutouts forming arms 222a-b. In embodiments in which the radiating structure 221 is formed from a conductive plate, assembly and mechanical misalignment of the resonant structure are minimized due to typically tight tolerances in fabrication and manufacturing. Advantageously, such structures provide more robust and reproducible electromagnetic waves. Furthermore, the design of the radiating structure 221 provides scaling to accommodate multiple radial zones for the generated electromagnetic field.

[0065] In an embodiment, the endpoints of each arm 222a-b are disposed at different angles measured from the center point of radiating structure 221 (i.e., a spiral arm embodiment). In an embodiment, the endpoints of each arm 222a-b are disposed at the same angle measured from the center point of radiating structure 221 (i.e., a radial arm embodiment).

[0066] In an embodiment, each arm 222a-b is additionally supported by one or more non-conductive offsets along the arc of the arm 222a-b.

[0067] In an embodiment, each first arm 222a has the same linear distance between its ends. In an embodiment, each second arm 222b has the same linear distance between its ends.

[0068] In an embodiment, the linear distance between the ends of each first spiral arm 222 a is different from the linear distance between the ends of each second spiral arm 222 b. In an embodiment, the linear distance between the ends of each first spiral arm 222 a is the same linear distance as the linear distance between the ends of each second spiral arm 222 b.

[0069] In an embodiment, positioning the arms 222a-b includes positioning the arms 222a-b such that the dimensions and shape of the arms 222a-b do not change during rotation of the radiating structure 221 about the axis of symmetry.

[0070] Each arm has an associated inductance value based on its physical dimensions and material composition. Thus, an inductor is formed with each arm along which there is a phase shift in the propagating electromagnetic wave that matches in sign with the phase change of an ideal lamp circuit inductor.

[0071] It should be appreciated that in embodiments, as discussed further below, the conductive offset mechanically and conductively attaches the end of each arm to a capacitive plate within the interface structure of the resonant structure. In such embodiments, the use of the language of an inductor formed by the arms is for ease and simplicity of discussion and is non-limiting. For example, it should be understood that the conductive offset, in combination with each arm, forms, in a general sense, the inductor of the resonant structure.

[0072] As shown, in the radiating structure 221, a first end of each first arm 222a is connected to an inner ring 223 and at the other end to an outer ring 225. The inner ring 223 is coupled to a first terminal of a first capacitor 230 and a first terminal of a second capacitor 232. The second terminal of the first capacitor 230 is coupled to the RF source 102. The second terminal of the second capacitor 232 is coupled to an RF ground 238. The outer ring 225 is coupled to a first terminal of a third capacitor 234. The second terminal of the third capacitor is coupled to the RF ground 238.

[0073] In embodiments in which the radiating structure 221 does not include the inner ring 223 , the first end of each first arm 222 a is connected to a first terminal of the first capacitor 230 and a first terminal of the second capacitor 232 .

[0074] 2A, the representation is of a capacitively coupled resonant structure, but it should be appreciated that this disclosure contemplates inductively coupled resonant structures as well, and therefore the capacitively coupled resonant structure in FIG.

[0075] In an embodiment, a first end of each arm 222b is connected to the inner ring 223. The other end of each arm 222b is coupled to a first terminal of a fourth capacitor 236. A second terminal of the fourth capacitor 236 is coupled to RF ground 238.

[0076] In embodiments in which the radiating structure 221 does not include an inner ring 223, the first end of each arm 222b is connected to a first terminal of the first capacitor 230 and a first terminal of the second capacitor 232 via a conductive offset, as discussed in further detail below.

[0077] As shown, the second capacitor 232, the third capacitor 234, and each of the first arms 222a form a respective first resonant circuit (i.e., an LC resonant circuit), and the second capacitor 232, the fourth capacitor 236, and each of the second arms 222b form a respective second resonant circuit (i.e., an LC resonant circuit).

[0078] In an embodiment, the coupling of the first terminal of the third capacitor 234, the first terminal of the fourth capacitor 236, or both terminals to RF ground may be adjusted electrically or mechanically. For example, a switch (not shown) having a first terminal coupled to the first terminal of the third capacitor 234 or the first terminal of the fourth capacitor 236 and a second terminal coupled to RF ground 238 may function to change the coupling to RF ground 238.

[0079] As another example, the capacitance values ​​associated with the third capacitor 234 and the fourth capacitor 236 of the resonant system 200 may be selected so that the first and second resonant circuits operate at the same frequency. In such an embodiment, changing the capacitance of either the third capacitor 234 or the fourth capacitor 236, respectively, shifts the resonant frequency of the first or second resonant circuit. In this mode of operation, the shifted resonant circuit may be removed from operation because the new resonant frequency is removed from the original single frequency.

[0080] In embodiments, the shifted resonant circuit coupled to RF ground remains operational, but the current distribution and associated plasma generated therefrom is shifted. In such embodiments, the resonant structure 200 can operate as a single resonant antenna or a parallel resonant antenna, depending on the desired application and configuration of the resonant structure 200.

[0081] For clarity, parallel resonance as used in this disclosure should not be interpreted in the usual technical electrical engineering sense of two or more circuit elements having a common voltage between them. Generally, in RF applications, voltage is path-dependent. Therefore, the concept of parallel circuit elements defined in terms of voltage is not strictly applicable. As used herein, the term refers in a looser, non-technical sense to two RF elements that are individually resonant, spatially adjacent, or in close proximity to each other. They can be excited simultaneously or each can be excited with a pulse that is separate in time from the other.

[0082] In an embodiment, the second capacitor 232 and the third capacitor 234 provide a low impedance path to the first resonant circuit, specifically to the radiating element of the radiating structure 221 (ie, the first set of arms 222a).

[0083] In an embodiment, the second capacitor 232 and the fourth capacitor 236 provide a low impedance path to the second resonant circuit, specifically the radiating element (i.e., the second set of arms 222b). In an embodiment, the inner ring 223 and the outer ring 225 of the radiating structure 221 form a low impedance path at the frequency of interest for each resonant circuit.

[0084] Here, RF source 102 is shown as an AC power source. In an embodiment, RF source 102 is configured to provide a forward RF wave to each arm, the forward RF wave being radiated by the first and second resonant circuits.

[0085] The resonant frequency of each resonant circuit is based on various electrical and mechanical parameters of the associated capacitor and structural components of the arm.

[0086] In embodiments, differences in arm lengths in each set allow for differences in inductance in each resonant circuit. In some embodiments, second capacitor 232, third capacitor 234, and fourth capacitor 236 are variable capacitors. In such embodiments, the resonant frequency of each resonant circuit can be adjusted by changing the capacitance value of the variable capacitor.

[0087] In embodiments, changing the balance of power between the resonant frequencies of the first set of arms 222a and the second set of arms 222b radially shifts the radius of maximum azimuthal average field that includes both sets of arms. Based on these configurations, varying the power ratio between the associated frequencies of each resonant circuit can change the high magnetic field point on the first set of arms 222a given the second set of arms 222b, which directly affects the density profile of the plasma generated by the resonant structure 200.

[0088] Thus, in one mode of operation, the resonant structure 200 is configured to simultaneously resonate at different resonant frequencies through the first and second resonant circuits, allowing for center-to-edge variation of the plasma density profile. In the second mode of operation, the resonant structure 200 can resonate at a single resonant zone and a single frequency by adjusting the capacitance values ​​of the resonant circuits to operate at the same resonant frequency. In the third mode of operation, the resonant structure 200 can resonate at a single resonant frequency but can resonate with multiple resonant zones. In embodiments where the resonant structure can operate at more than two resonances, different combinations of active resonant frequencies are also contemplated.

[0089] While the set of arms in radiating structure 221 is shown as having four arms, this number is non-limiting and different numbers of arms are contemplated. Furthermore, while radiating structure 221 is shown as having two resonant circuits resulting from two sets of arms 222a-b, it should be appreciated that radiating structures having more than two sets of arms are also contemplated. In such embodiments, each set of arms allows for a separate resonant structure.

[0090] Thus, in one embodiment having N sets of arms and M arms in each set, the radiating structure has M resonant circuits operating at the same resonance, of which there are N different types of resonant circuits, where M and N are positive integers. In different embodiments, each of the N sets may have a different number of arms.

[0091] Referring to Figure 2B, which is a cross-sectional view of the resonant structure 200 taken along line AA, two arms of the set of first arms 222a are shown. Referring to Figure 2C, which is a cross-sectional view of the resonant structure 200 taken along line BB, two arms of the set of second arms 222b are shown. Each of the first and second arms 222a and 222b is coupled to an interface structure 206 of the resonant structure 200 via a respective conductive offset 224a-d.

[0092] Although the resonant structure 200 is shown coupled to the RF source 102 using capacitive coupling, other arrangements, such as inductive coupling, are contemplated as well. Capacitive and inductive coupling arrangements are discussed in detail in U.S. patent application Ser. Nos. 17 / 664,607, 17 / 649,823, and 17 / 748,737, all of which are incorporated herein by reference.

[0093] Also shown are housings 226a-c that enclose resonant structure 200. Housings 226a-c include housing sidewalls 226a, housing bottom surfaces 226b, and housing top surfaces 226c. Housing sidewalls 226a and housing bottom surfaces 226b are conductive structures. Housing top surface 226c is shown with dashed lines representing the open sides of housings 226a-c.

[0094] The housing bottom surface 226b is electrically coupled to the RF ground 238 of the RF source 102. Thus, the entire housing 226a-c is RF grounded. The housing bottom surface 226b includes an opening for coupling an RF feed path from the RF source 102 to the interface structure 206.

[0095] In one embodiment, the housing top surface 226c is positioned adjacent to the bottom of the plasma chamber 106. Referring to FIG. 1 , the resonant structure 200 is turned upside down, and the housing top surface 226c of the resonant structure 200 is positioned so that the dielectric plate 114 is flush with the housing top surface 226c. In such an embodiment, the dielectric plate 114 is located above the radiating structure 221 in the direction of the housing top surface 226c. The resonant structure 200 generates electromagnetic waves that radiate through the dielectric plate 114 toward the plasma chamber 106 in a direction from the housing bottom surface 226b to the housing top surface 226c.

[0096] The resonant structure 200 may operate as the resonant structure 104 in the plasma processing system 100 of Figure 1. It should be noted that the resonant structure 200 is not limited to applications in plasma processing, and other applications are contemplated. Furthermore, the resonant structure 200 may include additional components not depicted in Figures 2A-C, such as a non-conductive offset that mechanically connects the radiating structure 221 to the interface structure 206, thereby providing additional structural rigidity to the resonant structure 200.

[0097] Interface structure 206 includes drive disk 202, capacitive inner rings 210a-b, capacitive outer rings 212a-b, and insulating structure 214. Drive disk 202 is a conductive circular structure that can be coupled to RF source 102 and is used to provide RF waves to radiating structure 221. In embodiments, drive disk 202 is coupled to RF source 102 via a rigid, semi-rigid, or flexible coaxial cable. In other embodiments, drive disk 202 is coupled to an RF or microwave generator via any one of a variety of types of transmission line, such as a rectangular waveguide, two parallel conductive ribbons having two cylindrical conductors contained within a larger hollow cylinder (e.g., a triax), etc.

[0098] The capacitive inner rings 210a-b and the capacitive outer rings 212a-b are conductive structures. As shown, the capacitive outer rings 212a-b are adjacent to the capacitive inner rings 210a-b and are disposed in substantially the same plane. However, in embodiments, the capacitive outer rings 212a-b may be in a different plane than the capacitive inner rings 210a-b. In either case, the surface area and insulating structures 214 forming each capacitive plate may be adjusted to have the same or different capacitances.

[0099] The capacitive outer rings 212a-b and the capacitive inner rings 210a-b are conductive ring-shaped plates having inner and outer radii. In an embodiment, the capacitive outer rings 212a-b and the capacitive inner rings 210a-b have the same center point as the drive disk 202. The inner radii of the capacitive outer rings 212a-b are larger than the outer radii of the capacitive inner rings 210a-b. The inner radii of the capacitive inner rings 210a-b are smaller than the outer radius of the drive disk 202.

[0100] In embodiments, the capacitive inner rings 210a-b are a single conductive structure, effectively forming a single capacitive inner ring. In other embodiments, each capacitive inner ring 210a-b is a single conductive structure. In such embodiments, the multiple conductive structures may be electrically isolated from each other (e.g., 210a and 210b). In embodiments, the capacitive outer rings 212a-b are a single conductive structure, effectively forming a single capacitive outer ring. In other embodiments, each capacitive outer ring 212a-b is a single conductive structure. In such embodiments, the multiple conductive structures may be electrically isolated from each other (e.g., 212a and 212b).

[0101] For example, in embodiments, each first arm 222a is coupled at one end to a first conductive structure of the capacitive inner ring 210a, and each second arm 222b is coupled at one end to a second conductive structure of the capacitive inner ring 210a. The first and second conductive structures of the capacitive inner rings 210a-b may be electrically coupled to each other in one set of embodiments, or may be electrically isolated from each other in a different set of embodiments.

[0102] Similarly, in embodiments, each first arm 222a is coupled at one end to a first conductive structure of the capacitive outer ring 212a, and each second arm 222b is coupled at one end to a second conductive structure of the capacitive inner ring 210b. The first and second conductive structures of the capacitive outer rings 212a-b may be electrically coupled to each other in one set of embodiments, or may be electrically isolated from each other in a different set of embodiments.

[0103] In the embodiment, the RF source 102 is electromagnetically coupled to the capacitive inner rings 210a-b via the driving disk 202. Although not shown, as previously mentioned, the RF source 102 can be coupled to the resonant structure using inductive coupling. Therefore, the coupling method of the RF source 102 is not limited.

[0104] 2B-C show cross-sectional views of the resonant structure 200, it should be appreciated that in embodiments, an axis of symmetry exists at the center of the resonant structure 200. In embodiments, the resonant structure 200 has a cylindrical structure. In these embodiments, for example, the portion of the capacitive outer rings 212a-b shown on the left side of the drive disk 202 and the portion of the capacitive outer rings 212a-b shown on the right side of the drive disk 202 are part of the same conductive ring structure. Furthermore, similar symmetry exists with respect to the center of the resonant structure with other components of the resonant structure 200, such as the capacitive inner rings 210a-b, the radiating structure 221, etc.

[0105] The insulating structure 214 is comprised of an electrically insulating material, such as a dielectric material. In an embodiment, the insulating structure 214 is comprised of air or a vacuum. The insulating structure 214 is disposed between the drive disk 202, the capacitive inner rings 210a-b, the capacitive outer rings 212a-b, and the housing bottom surface 226b.

[0106] In an embodiment, the interface structure 206 is embedded in an insulating medium, such as air or a dielectric (i.e., the insulating structure 214). While the arrow pointing to the insulating structure 214 is shown in Figure 2A to indicate an area, or more precisely, a volume, of the interface structure 206, it should be appreciated that the arrow is meant to imply that the insulating structure 214 covers an area or volume that surrounds the different conductive and non-conductive materials of the resonant structure 200.

[0107] In embodiments, the insulating structure 214 may include multiple insulating structures, for example, having different dielectric parameters, effectively forming a single insulating structure between the various conductive components of the interface structure 206. In other embodiments, the insulating structure 214 may be a single insulating structure formed between the various conductive components of the interface structure 206.

[0108] The conductive offsets 224a-d include a first set of inner conductive offsets 224a, a second set of inner conductive offsets 224b, a first set of outer conductive offsets 224c, and a second set of outer conductive offsets 224d.

[0109] As shown, the conductive offsets 224a-d are positioned perpendicular to the capacitive inner rings 210a-b, the capacitive outer rings 212a-b, and the radiating structure 221. However, the conductive offsets 224a-d can also be positioned to perpendicularly connect the capacitive inner rings 210a-b and the capacitive outer rings 212a-b to the radiating structure 221 without being perpendicular to these surfaces.

[0110] In an embodiment, a first inner set of conductive offsets 224a electrically couples the capacitive inner ring 210a to the inner ring 223 of the radiating structure 221. An outer set of conductive offsets 224c electrically couples the capacitive outer ring 212a to the outer ring 225 of the radiating structure 221.

[0111] For ease of discussion herein, each of the capacitive inner rings 210a-b and each of the capacitive outer rings 212a-b is considered to be a single conductive structure. Accordingly, the capacitive plates forming a capacitor, as disclosed herein, are discussed in terms of a single corresponding structure. However, it should be understood that, in embodiments, a capacitor can be formed separately with one of the capacitive inner rings 210a, one of the capacitive inner rings 210b, or both, each as a side of parallel capacitive plates. Similarly, a capacitor can be formed separately with one of the capacitor outer rings 212a, one of the capacitor outer rings 212b, or both, each as a side of parallel capacitive plates.

[0112] First capacitor 230 (C 230 ) is formed by the driving disk 202, the insulating structure 214, and the capacitive inner rings 210a-b. The driving disk 202 and the capacitive inner ring 210a are conductive plates arranged parallel to one another and sandwiching the insulating structure 214 therebetween, forming a parallel plate capacitor. The driving disk 202 is capacitively coupled to the capacitive inner rings 210a-b, as illustrated by the first capacitor 230.

[0113] The second capacitor 232 (C 232 ) is formed by the housing bottom surface 226b, the insulating structure 214, and the capacitive inner rings 210a-b. The housing bottom surface 226b and the capacitive inner rings 210a-b are conductive plates arranged in parallel and sandwiching the insulating structure 214 therebetween, forming a parallel plate capacitor. In an embodiment, the capacitance value of the second capacitor 232 is greater than 10 picofarads (pF). The capacitance value is approximately the same at each position of the parallel plate capacitor.

[0114] The third capacitor 234 (C234 ) is formed by the housing bottom surface 226b, the insulating structure 214, and the capacitive outer rings 212a-b. The housing bottom surface 226b and the capacitive outer ring 212a are conductive plates arranged in parallel and sandwiching the insulating structure 214 therebetween, forming a parallel plate capacitor. In an embodiment, the capacitance value of the third capacitor 234 is greater than 10 picofarads (pF). The capacitance value is approximately the same at each position of the parallel plate capacitor.

[0115] A fourth capacitor 236 (C 236 ) is formed by the housing bottom surface 226b, the insulating structure 214, and the capacitive outer rings 212a-b. The housing bottom surface 226b and the capacitive outer rings 212a-b are conductive plates arranged in parallel and sandwiching the insulating structure 214 therebetween, forming a parallel plate capacitor. In an embodiment, the capacitance value of the second capacitor 232 is greater than 10 picofarads (pF). The capacitance value is approximately the same at each position of the parallel plate capacitor.

[0116] In an embodiment, the second terminals of the second capacitor 232, the third capacitor 234, and the fourth capacitor 236 are different plates from the housing bottom surface 226b. For example, a separate capacitive plate may be positioned between the housing bottom surface 226b and the capacitive outer ring 212b or the capacitive inner ring 212a to form a parallel plate capacitor (not shown).

[0117] In some embodiments, the capacitance value of the third capacitor 234 is equal to the capacitance value of the fourth capacitor 236. In other embodiments, the capacitance value of the third capacitor 234 is not equal to the capacitance value of the fourth capacitor 236.

[0118] In one embodiment, the ends of each of the inner sets of conductive offsets 224a-b are positioned equal distances from each other along the surface of the capacitive inner rings 210a-b.

[0119] In one embodiment, the ends of each of the outer sets of conductive offsets 224c-d are positioned equal distances from each other along the surface of the capacitive outer rings 212a-b.

[0120] 2D shows a first resonant region 250 from a first resonant circuit operating in isolation, a second resonant region 260 from a second resonant circuit operating in isolation, and an overlapping resonant region 270 from the first and second resonant circuits operating simultaneously. A resonant region as used herein refers to the transmission of a field or fields generated by an associated resonant structure in isolation or in combination.

[0121] As shown, in the combined resonance region 270 (i.e., when the resonant structure 200 is operating at multiple resonances simultaneously), plasma generation in the overlap region 272 has contributions from both the first and second resonant circuits. In contrast, the non-overlapping region 274 is the product of only the first resonant circuit. Thus, modifying various adjustable parameters of the resonant structure 200, or adjusting the power ratio between the resonant frequencies, allows for control of the center-to-edge density profile of the plasma generated by the resonant structure 200.

[0122] 3A shows a hybrid schematic diagram of one embodiment of a resonant structure 300. The resonant structure 300 may operate as the resonant structure 104 in the plasma processing system 100 of FIG. 1. It should be noted that the resonant structure 300 is not limited to applications in plasma processing, and other applications are also contemplated.

[0123] Resonant structure 300 shares several features with resonant structure 200. Resonant structure 300 includes a radiating structure 321, shown as a unitary, conductive, planar, ring-shaped structure. Radiating structure 321 includes an inner ring 223, an outer ring 225, a first set of arms 322a, and a second set of arms 322b. Each arm in each set of arms 322a-b has n-fold symmetry about an axis passing through the center point of radiating structure 321.

[0124] In the resonant structure 200 , similar to the resonant structure 300 , the RF forward wave can be capacitively coupled from the RF source 102 through either the inner ring 223 or the outer ring 225 .

[0125] Each first arm 322a is connected at one end to the inner ring 223 and at the other end to the outer ring 225. The outer ring 225 is coupled to a first terminal of a first capacitor 230 and a first terminal of a second capacitor 232. The second terminal of the first capacitor 230 is coupled to the RF source 102. The second terminal of the second capacitor 232 is coupled to an RF ground 238. The inner ring 223 is coupled to a first terminal of a third capacitor 234. The second terminal of the third capacitor 234 is coupled to the RF ground 238.

[0126] Each second arm 322b is connected at one end to the outer ring 225. The other end of each second arm 322b is coupled to a first terminal of a fourth capacitor 236. A second terminal of the fourth capacitor 236 is coupled to RF ground 238.

[0127] The second capacitor 232, the third capacitor 234, and each of the first arms 322a form a respective first resonant circuit (i.e., an LC resonant circuit), and the second capacitor 232, the fourth capacitor 236, and each of the second arms 322b form a respective second resonant circuit (i.e., an LC resonant circuit).

[0128] FIG. 3B shows a first resonance region 350 from a first resonant circuit operating in isolation, a second resonance region 360 from a second resonant circuit operating in isolation, and an overlapping resonance region 370 from the first and second resonant circuits operating simultaneously.

[0129] As shown, in the overlapping resonance region 370 (i.e., when the resonant structure 300 is operating at multiple resonances simultaneously), the overlapping region 374 is a product of both the first and second resonant circuits. In contrast, the non-overlapping region 372 is a product of only the first resonant circuit. Thus, operating the first and second resonant circuits of the resonant structure 300 at different frequencies allows for control of the edge-to-center density profile of the plasma generated by the resonant structure 300.

[0130] Figure 4 shows a hybrid schematic diagram of one embodiment of a resonant structure 400. The resonant structure 400 may operate as the resonant structure 104 in the plasma processing system 100 of Figure 1. It should be noted that the resonant structure 400 is not limited to applications in plasma processing, and other applications are also contemplated.

[0131] Resonant structure 400 shares several features with resonant structure 200. Resonant structure 400 includes a radiating structure 421, shown as a unitary, conductive, planar, ring-like structure. Radiating structure 421 includes inner ring 223, a first set of arms 422a, and a second set of arms 422b. Each arm of each set of arms 422a-b has n-fold symmetry about an axis passing through the center point of radiating structure 421.

[0132] Each first arm 422a is connected at one end to the inner ring 223 and at the other end to a first terminal of a third capacitor 234. The inner ring 223 is coupled to a first terminal of a first capacitor 230 and a first terminal of a second capacitor 232. The second terminal of the first capacitor 230 is coupled to the RF source 102. The second terminal of the second capacitor 232 is coupled to RF ground 238. The second terminal of the third capacitor 234 is coupled to RF ground 238.

[0133] Each second arm 422b is connected at one end to the inner ring 223. The other end of each second arm 422b is coupled to a first terminal of a fourth capacitor 236. The second terminal of the fourth capacitor 236 is coupled to RF ground 238. As shown, the physical dimensions of the arms in the set of first arms 422a are identical to the physical dimensions of the arms in the set of second arms 422b. Therefore, the inductance of each arm is the same for the set of first arms 422a and the set of second arms 422b.

[0134] The second capacitor 232, the third capacitor 234, and each of the first arms 422a form a respective first resonant circuit (i.e., an LC resonant circuit), and the second capacitor 232, the fourth capacitor 236, and each of the second arms 422b form a respective second resonant circuit (i.e., an LC resonant circuit).

[0135] 2B-C, Figure 5A illustrates an embodiment of a first conductive plate 500 of the capacitive outer ring 212a to which the first arm 422a is coupled. Figure 5B illustrates an embodiment of a second conductive plate 520 of the capacitive outer ring 212b to which the second arm 422b is coupled.

[0136] In an embodiment, each first arm 422a is coupled to a first conductive plate 500 of the outer ring 212a via a conductive offset 224c at a connection point 504. In an embodiment, each second arm 422b is coupled to a second conductive plate 520 of the outer ring 212b via a conductive offset 224d at a connection point 524.

[0137] The first conductive plate 500 lacks an overlap region (i.e., is electrically isolated from one another) and is positioned within the inner ring cutout of the second conductive plate 520. Thus, in combination, the first conductive plate 500 and the second conductive plate 520 shown in FIGS. 5A-B form the outer rings 212a-b. The capacitance of the third capacitor 234 in the first resonant circuit depends on the material and dimensional parameters of the first conductive plate 500. Similarly, the capacitance of the fourth capacitor 236 in the second resonant circuit depends on the material and dimensional parameters of the second conductive plate 520.

[0138] In an embodiment, the first conductive plate 500 is in the same plane as the second conductive plate 520 with respect to the vertical arrangement of the resonant structure 400, while in other embodiments the plates may be arranged in different planes but parallel to each other.

[0139] It should be noted that one factor determining the capacitance of each of third capacitor 234 and fourth capacitor 236 is the dielectric parameters of insulating structure 214 between first conductive plate 500 and housing bottom surface 226b and insulating structure 214 between second conductive plate 520 and housing bottom surface 226b, respectively. As described in further detail below, in embodiments, insulating structure 214 may be different for each of these capacitors.

[0140] It should be appreciated that while first conductive plate 500 and second conductive plate 520 are sized for two sets of arms, each having four arms, additional capacitive or conductive plates that can be connected to different numbers of arms are also contemplated.

[0141] In an embodiment, various conductive plates allow for shorter antenna segments and axial symmetry.

[0142] 5C illustrates one embodiment of a segmented outer ring 540, which may represent, for example, capacitive outer rings 212a-b in FIGS. 2B-C. Segmented outer ring 540 illustrates two sets of first and second segments 542a and 542b, each having four segments. Each first arm 422a is coupled to a respective first segment 542a via a conductive offset 224c. Each second arm 422a is coupled to a respective second segment 542b via a conductive offset 224d.

[0143] In embodiments, each segment in each set of first and second segments 542a and 542b may have different dimensions or be of different materials. In some embodiments, each of the segments 542a has the same dimensions and is of the same material. In some embodiments, each of the segments 542b has the same dimensions and is of the same material. In some embodiments, each of the segments 542a-b has the same dimensions and is of the same material.

[0144] In embodiments, one or more segments are coupled to one or more segments 542a-b via a capacitor to create a shared capacitor. In such embodiments, the shared capacitor may be in the first resonant circuit, the second resonant circuit, or both the first and second resonant circuits.

[0145] 2B-C, Figure 6A illustrates one embodiment of a first dielectric plate 600 of the insulating structure 214. Figure 6B illustrates one embodiment of a second dielectric plate 620 of the insulating structure 214, with reference to Figures 2B-C.

[0146] In an embodiment, the first dielectric plate 600 is positioned within an inner ring cutout of the second dielectric plate 620 that lacks an overlap region. In another embodiment, the first dielectric plate 600 is positioned within an inner ring cutout of the second dielectric plate 620 that has an overlap region.

[0147] 6A-B, form part of the insulating structure 214. In embodiments, the first dielectric plate 600 is in the same plane as the second dielectric plate 620 with respect to the vertical orientation of the resonant structure 400, while in other embodiments the plates may be arranged in different planes but parallel to each other.

[0148] In an embodiment, the first conductive plate 500 and the second conductive plate 520 are positioned vertically above the first dielectric plate 600 and the second dielectric plate 620. In such an embodiment, the housing bottom surface 226b is positioned vertically below the first dielectric plate 600 and the second dielectric plate 620. A third capacitor 234 is formed by the first conductive plate 500, the first dielectric plate 600, and the housing bottom surface 226b. A fourth capacitor is formed by the second conductive plate 520, the second dielectric plate 620, and the housing bottom surface 226b.

[0149] In an embodiment, the segmented outer ring 540 is positioned vertically above the first dielectric plate 600 and the second dielectric plate 620. In such an embodiment, the housing bottom surface 226b is positioned vertically below the first dielectric plate 600 and the second dielectric plate 620.

[0150] The third capacitor 234 of each of the first resonant circuits is formed by the first segment 542a, the first dielectric plate 600, and the housing bottom surface 226b. The fourth capacitor 236 of each of the second resonant circuits is formed by the second segment 542b, the second dielectric plate 620, and the housing bottom surface 226b.

[0151] 6C illustrates, with reference to FIGS. 2B-C, one embodiment of a shared dielectric plate 640 as represented by insulating structure 214. In such an embodiment, the same insulating structure 214 is shared between third capacitor 234 and fourth capacitor 236.

[0152] In one embodiment where the resonant structure 400 is used in combination with a shared dielectric plate 640, the selection of the materials and dimensions of the first conductive plate 500 and the second conductive plate 520, or the materials and dimensions (or connectivity between the segments) of the segmented outer ring 540, controls the resonant frequencies of the first resonant circuit and the second resonant circuit.

[0153] In embodiments, the insulating structures 214 between each segment and the housing bottom 226b are equal in value. In some embodiments, the insulating structures 214 between each segment and the housing bottom 226b are different in value. In other embodiments, the insulating structures 214 of the first segment 542a are equal in value and the insulating structures 214 of the second segment 542b are equal in value but different in value from the insulating structures 214 associated with the first segment 542a.

[0154] In the embodiment, not only are the capacitances of the third capacitor 234 and the fourth capacitor 236 different, but the capacitances of the respective third capacitor 234 and fourth capacitor of each previously specified resonant circuit are different in value.

[0155] Therefore, it should be appreciated that each of the third capacitor 234 and the fourth capacitor 236 can be adjusted or controlled by varying the respective segments, by changing the underlying dielectric, or a combination thereof.

[0156] As disclosed herein, combinations with various dielectric and conductive plates provide different resonant structures capable of operating as single or parallel resonant antennas. Accordingly, the embodiments explicitly disclosed herein are non-limiting. For the sake of brevity, it should be appreciated that other combinations based on the materials of the present disclosure may also be considered that provide advantageous single or parallel resonant operation in a single resonant structure.

[0157] It should be noted that although the described embodiment utilizes the structures described in Figures 5 and 6 for the outer capacitor rings 212a-b, those structures are also applicable to the inner capacitor rings 210a-b.

[0158] For example, while each of the arms in radiating structure 421 in FIG. 4 is shown coupled at one end to inner ring 223 and at the other end to capacitive outer ring 212a-b via conductive offset 224b, radiating structures are also contemplated in which each arm is coupled at one end to outer ring 225 and coupled to inner ring 210a-b via conductive offset 224a with arms of equal length throughout.

[0159] As another example, an embodiment is contemplated in which the radiating structure has arms of equal length, each arm being coupled at one end to an outer ring of the radiating structure and at the other end to an inner ring of the radiating structure.

[0160] As yet another example, an embodiment is also contemplated in which the radiating structure does not have an inner ring 223 or an outer ring 225, but has arms of equal length, each coupled at one end to the outer capacitive ring of the radiating structure via a conductive offset 224c-d and at the other end to the inner capacitive ring via a conductive offset 224a-b.

[0161] For each, the radiating structure can be used in combination with either (i) the first conductive plate 500 and the second conductive plate 520, or (ii) the segmented outer ring 540, and it is contemplated that (i) one of the first dielectric plate 600 and the second dielectric plate 620, or (ii) the shared dielectric plate 640, controls the capacitance value of the third capacitor 234 or the fourth capacitor 236.

[0162] It should be appreciated that embodiments having inner rings 210a-b with configurations as described with conductive plate 500 and second conductive plate 520 or segmented outer ring 540 are also contemplated. In such embodiments, the general shape and structure of the conductive plates are retained, but are reduced in size to accommodate the smaller dimensions of the inner rings 210a-b. Similarly, the dielectric material between these conductive plates and the housing bottom surface 226b for the inner rings 210a-b may have the same general shape and structure as the first dielectric plate 600 and second dielectric plate 620 or the shared dielectric plate 640. In these embodiments, the second capacitor 232 for each resonant circuit may have the same or different capacitance value based on the combination of conductive or dielectric plates used to form the resonant structure. Furthermore, any combination of outer rings 212a-b and inner rings 210a-b based on the above conductive and dielectric plates, as well as any of the resonant structures detailed above, may be contemplated. Finally, any combination lacking the outer ring 225 and inner ring 223 is also contemplated. In such an embodiment, the arms are coupled to interface structure 206 via conductive offsets 224a-d.

[0163] Although described in detail, it should be understood that various changes, substitutions, and alterations may be made therein without departing from the spirit and scope of the present disclosure, as defined by the appended claims. Like elements in the various figures are designated with like reference numerals. Moreover, the scope of the present disclosure is not intended to be limited to the particular embodiments described herein; those skilled in the art will readily recognize from this disclosure that any now-existing or later-developed process, machine, manufacture, composition of matter, means, method, or step may perform substantially the same function or achieve substantially the same result as the corresponding embodiment described herein. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

[0164] The specification and drawings, therefore, should be considered merely as illustrative of the present disclosure as defined by the appended claims, and are intended to cover any and all modifications, variations, combinations, or equivalents that fall within the scope of the present disclosure. For example, it should be appreciated that the physical placement and arrangement of components in various embodiments of the plasma processing system or resonant structure is non-limiting. For example, while the resonant structure is located between the RF source and the plasma processing system in various illustrations, this placement is non-limiting, and these components may be located near, above, or below other components while remaining within the scope of the present disclosure.

Claims

1. 1. A radiating structure of a resonant structure used for plasma processing, comprising: a set of first arms, each first arm having a first inductance and coupled to a respective first capacitor and a respective second capacitor of the resonant structure to form a corresponding first resonant circuit operating at a first resonant frequency; a set of second arms, each second arm having a second inductance and coupled to a respective third capacitor and a respective fourth capacitor of the resonant structure to form a corresponding second resonant circuit operating at a second resonant frequency, wherein in a first mode of operation the resonant structure operates as a single resonant antenna and in a second mode of operation the resonant structure operates as a parallel resonant antenna; radiating structure.

2. 10. The radiating structure of claim 1, wherein each first arm has the same first length and each second arm has the same second length that is different from the first length.

3. The radiating structure of claim 1 , wherein each of the first and second arms is a spiral.

4. The radiating structure of claim 3 , wherein each first arm and each second arm is Archimedes, logarithmic, Fibonacci, an involute of a circle, or a linear spiral.

5. 2. The radiating structure of claim 1, further comprising an inner ring and an outer ring, wherein the inner ring has a diameter smaller than the diameter of the outer ring, the inner ring and the outer ring have the same center point, each first arm and each second arm has a first end point coupled to the inner ring, each first arm has a second end point coupled to the outer ring, and each second arm has a second end point mechanically decoupled from the outer ring.

6. 6. The radiating structure of claim 5, wherein the respective first capacitor and the respective third capacitor are the same capacitor coupled to the inner ring via a first conductive offset, the respective second capacitor is coupled to the outer ring via a second conductive offset, and the respective fourth capacitor is coupled to the second end point of each second arm via a third conductive offset.

7. 2. The radiating structure of claim 1, further comprising an inner ring and an outer ring, wherein the diameter of the inner ring is smaller than the diameter of the outer ring, the inner ring and the outer ring have the same center point, each first arm and each second arm has a first end point coupled to the outer ring, each first arm has a second end point coupled to the inner ring, and each second arm has a second end point mechanically decoupled from the inner ring.

8. 8. The radiating structure of claim 7, wherein the respective first capacitors and the respective third capacitors are the same capacitor that is coupled to the outer ring via a first conductive offset, the respective second capacitors are coupled to the inner ring via a second conductive offset, and the respective fourth capacitors are coupled to the second end point of each second arm via a third conductive offset.

9. 2. The radiating structure of claim 1, wherein each first arm and each second arm has the same length, the respective first capacitor is coupled to a first end of each first arm via a first conductive offset, the respective second capacitor is coupled to a second end of each first arm via a second conductive offset, the respective third capacitor is coupled to a first end of each second arm via a third conductive offset, and the respective fourth capacitor is coupled to a second end of each second arm via a fourth conductive offset.

10. 2. The radiating structure of claim 1, wherein each respective first capacitor is coupled to every other respective first capacitor, each respective second capacitor is coupled to every other respective second capacitor, each respective third capacitor is coupled to every other respective third capacitor, and each respective fourth capacitor is coupled to every other respective fourth capacitor.

11. 2. The radiating structure of claim 1, further comprising an inner ring and an outer ring, wherein the diameter of the inner ring is smaller than the diameter of the outer ring, the inner ring and the outer ring have the same center point, each first arm and each second arm has a first end point coupled to the inner ring, and each first arm and each second arm has a second end point coupled to the outer ring.

12. 10. The radiating structure of claim 1, wherein in said second mode of operation, a density profile of the plasma generated by said resonant structure is controlled radially by adjusting an RF waveform corresponding to each resonant circuit.

13. 1. A radiating structure of a resonant structure used for plasma processing, comprising: a first set of arms coupled at a first end to a first capacitive plate of the resonant structure and at a second end to a second capacitive plate of the resonant structure to form a first set of resonant circuits operating at a first resonant frequency; a second set of arms coupled at a first end to the first capacitive plate of the resonant structure and at a second end to a third capacitive plate of the resonant structure to form a second set of resonant circuits operating at a second resonant frequency, wherein in a first mode of operation, the resonant structure operates as a single resonant antenna and in a second mode of operation, the resonant structure operates as a parallel resonant antenna. radiating structure.

14. 14. The radiating structure of claim 13, wherein in the second mode of operation, a density profile of the plasma generated by the resonant structure is controlled radially by adjusting RF waveforms corresponding to the first resonant frequency and the second resonant frequency.

15. 14. The radiating structure of claim 13, wherein the first capacitive plate is formed by a first conductive plate, a first dielectric, and a bottom surface of a housing of the resonant structure, the second capacitive plate is formed by a second conductive plate, a second dielectric, and the bottom surface of the housing of the resonant structure, and the third capacitive plate is formed by a third conductive plate, a third dielectric, and the bottom surface of the resonant structure.

16. 14. The radiating structure of claim 13, wherein the first set of arms and the second set of arms are arranged in a repeating radial pattern.

17. 14. The radiating structure of claim 13, wherein each first arm has the same first length and each second arm has the same second length that is different from the first length.

18. 1. A resonant structure for plasma processing, comprising: a first capacitive plate, a second capacitive plate, a third capacitive plate, and a fourth capacitive plate; a first set of arms coupled at a first end to the first capacitive plate and at a second end to the second capacitive plate to form a first set of resonant circuits operating at a first resonant frequency; a second set of arms coupled at a first end to the third capacitive plate and at a second end to the fourth capacitive plate to form a second set of resonant circuits operating at a second resonant frequency, wherein in a first mode of operation, the resonant structure operates as a single resonant antenna and in a second mode of operation, the resonant structure operates as a parallel resonant antenna. Resonant structure.

19. 20. The resonant structure of claim 18, wherein in the second mode of operation, a density profile of the plasma generated by the resonant structure is controlled radially by adjusting RF waveforms corresponding to the first resonant frequency and the second resonant frequency.

20. 20. The resonant structure of claim 18, wherein the first capacitive plate is formed by a first conductive plate, a first dielectric, and a bottom surface of a housing of the resonant structure, the second capacitive plate is formed by a second conductive plate, a second dielectric, and the bottom surface of the housing of the resonant structure, the third capacitive plate is formed by a third conductive plate, a third dielectric, and the bottom surface of the resonant structure, and the fourth capacitive plate is formed by a fourth conductive plate, a fourth dielectric, and the bottom surface of the resonant structure.

21. 20. The resonant structure of claim 18, wherein each first arm and each second arm is an Archimedean spiral, each first arm having the same first length and each second arm having the same second length that is different from the first length.

22. 20. The resonant structure of claim 18, wherein each of the first and second arms is an Archimedean spiral, and each of the first and second arms has the same length.

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