CN117751422A

CN117751422A - Apparatus for plasma processing

Info

Publication number: CN117751422A
Application number: CN202280054492.5A
Authority: CN
Inventors: 巴顿·莱恩; 山泽阳平; 詹森·D·梅希甘; 麦里特·法克
Original assignee: Tokyo Electron Ltd
Current assignee: Tokyo Electron Ltd
Priority date: 2021-08-20
Filing date: 2022-08-18
Publication date: 2024-03-22
Also published as: WO2023023289A1; TW202322179A; KR20240046497A

Abstract

According to an embodiment, an apparatus for a plasma processing system is provided. The device includes an interface, a radiating structure, and a conductive offset. The interface includes a first conductive plate coupleable to an RF source, a second conductive plate disposed between the RF source and the first conductive plate, and a concentric conductive ring structure disposed between the second conductive plate and a substrate holder. These conductive offsets are arranged to couple the concentric conductive ring structure to the radiating structure.

Description

Apparatus for plasma processing

Cross Reference to Related Applications

The present application claims the benefit of U.S. provisional application No. 63/235,418, filed 8/20 at 2021, which is incorporated herein by reference in its entirety.

Technical Field

The present disclosure relates generally to a semiconductor processing technique and, in particular embodiments, to an apparatus for radiating electromagnetic waves in a plasma processing system for processing a substrate in the plasma processing system.

Background

In the semiconductor industry, plasma processing is widely used in the manufacture and production of high density microcircuits.

In a plasma processing system, electromagnetic waves radiated into a plasma chamber generate an electromagnetic field. The generated electromagnetic field heats electrons in the chamber. The heated electrons ignite a plasma that processes the substrate in processes such as etching, deposition, oxidation, sputtering, and the like.

Non-uniform electromagnetic fields within the plasma processing chamber result in non-uniform processing of the substrate due to the different portions of the substrate being processed with plasmas of different densities. Accordingly, there is a need for an apparatus and system that improves the uniformity of electromagnetic fields in a plasma processing system.

Disclosure of Invention

A first aspect relates to an apparatus for a plasma processing system. The device includes an interface, a radiating structure, and a conductive offset. The interface includes a first conductive plate coupleable to an RF source, a second conductive plate disposed between the RF source and the first conductive plate, and a concentric conductive ring structure disposed between the second conductive plate and the substrate holder. These conductive offsets are arranged to couple the concentric conductive ring structure to the radiating structure.

In a first implementation form of the apparatus according to the first aspect as such, the second conductive plate is grounded.

In a second implementation form of the device according to the first aspect as such or any of the preceding implementation forms of the first aspect, the radiating structure comprises a third conductive plate having a plurality of axisymmetric spiral cuts.

In a third implementation form of the apparatus according to the first aspect as such or any of the preceding implementation forms of the first aspect, the plasma processing system comprises a processing chamber with a substrate holder. The substrate is mounted on a substrate holder for processing in a processing chamber.

In a fourth implementation form of the apparatus according to the first aspect as such or any of the preceding implementation forms of the first aspect, the apparatus is arranged outside the processing chamber.

In a fifth implementation form of the apparatus according to the first aspect as such or any of the preceding implementation forms of the first aspect, the first conductive plate is coupled to the RF source via a coaxial conductive structure, and the RF source feeds RF power to the first conductive plate via the coaxial conductive structure.

In a sixth implementation form of the device according to the first aspect as such or any of the preceding implementation forms of the first aspect, the device further comprises a non-conductive offset and the radiating structure is coupled to an insulating structure by the non-conductive offset, the insulating structure being arranged between the conductive inner ring structure of the concentric conductive ring structure and the conductive outer ring structure of the concentric conductive ring structure.

In a seventh implementation form of the device according to the first aspect as such or any of the preceding implementation forms of the first aspect, the interface, the radiating structure and the conductive offset form a resonant circuit in response to the RF source providing RF power to the first conductive plate.

A second aspect relates to an apparatus for a plasma processing system. The device includes an interface and a radiating structure coupled to the interface. The interface includes a first conductive structure coupleable to an RF source, a second conductive structure disposed between the RF source and the first conductive structure, and a concentric conductive structure. Each concentric conductive structure is isolated from the second conductive structure by an air gap.

In a first implementation form of the apparatus according to such a second aspect, each concentric conductive structure is isolated from adjacent concentric conductive structures by an air gap.

In a second implementation form of the device according to such a second aspect or any of the preceding implementation forms of the second aspect, the device further comprises a conductive offset coupling the concentric conductive structure to the radiating structure.

In a third implementation form of the device according to such a second aspect or any of the preceding implementation forms of the second aspect, the resonant frequency of the radiating structure is between 5 and 100 megahertz (MHz).

In a fourth implementation form of the apparatus according to such a second aspect or any of the preceding implementation forms of the second aspect, the radiating structure comprises a conductive plate with a plurality of spiral cuts and an inner circular cut. The first conductive structure is arranged substantially in the same plane as the radiating structure and is positioned within the inner circular cutout.

In a fifth implementation form of the apparatus according to such second aspect or any of the preceding implementation forms of the second aspect, the plasma processing system comprises a processing chamber with a substrate holder. A substrate to be processed in the processing chamber is mounted on a substrate holder.

A third aspect relates to an antenna system for exciting a plasma by inductive coupling. The antenna system includes a plate, a conductive loop structure, a conductive offset, and a plurality of spiral arms. The conductive ring structure is arranged parallel to the plate. The plate and the conductive ring structure form a first capacitor, and the capacitance value of the first capacitor is substantially the same along one conductive ring structure. Each conductive offset includes a first end and a second end, wherein the first end of each conductive offset is coupled to the conductive ring structure in a vertically disposed manner. Each conductive offset is disposed equidistant from the other conductive offsets along the conductive ring structure. A plurality of spiral arms are coupled to a corresponding second end of each conductive offset. Each spiral arm is arranged in a radial, azimuthal, and nested arrangement. Each spiral arm has the same shape, length and spacing. The plurality of spiral arms, the conductive offset, and the conductive loop structure form a resonant structure that resonates at an RF frequency.

In a first implementation form of the antenna system according to such a third aspect, the antenna system further comprises at least one driving conductive structure capacitively coupled to the resonant structure and coupleable to the RF source.

In a second implementation form of the antenna system according to such a third aspect or any of the preceding implementation forms of the third aspect, the antenna system further comprises a conductive coil structure inductively coupled to the resonant structure. The conductive coil structure and the resonant structure form an inductive coupling pair. The conductive coil structure may be coupled to an RF source.

In a third implementation form of the antenna system according to such a third aspect or any of the preceding implementation forms of the third aspect, the conductive loop structure comprises a conductive inner loop structure and a conductive outer loop structure adjacent to the conductive inner loop structure. Each of the conductive inner ring structure and the conductive outer ring structure is coupled to the plurality of spiral arms by a conductive offset.

In a fourth implementation form of the antenna system according to such a third aspect or any of the preceding implementation forms of the third aspect, one of the inner or outer edges of each of the plurality of spiral arms is connected to the conductive loop structure by a conductive offset and the other edge of each of the plurality of spiral arms is not directly connected to the conductive structure or to ground.

In a fifth implementation form of the antenna system according to such a third aspect as such or any of the preceding implementation forms of the third aspect, the plurality of spiral arms, the plate and the conductive loop structure are arranged substantially parallel to each other.

These embodiments may be implemented in hardware, software, or any combination thereof.

Drawings

For a more complete understanding of the present disclosure and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a diagram of an embodiment plasma processing system;

FIG. 2A is a side view of an embodiment resonant structure;

FIG. 2B is a schematic diagram of the resonant structure of the embodiment of FIG. 2A;

FIG. 2C is a flow chart of an embodiment method that may be performed by the embodiment resonating structure of FIG. 2A;

FIG. 3A is a side view of another embodiment resonant structure;

FIG. 3B is a schematic diagram of the resonant structure of the embodiment of FIG. 3A;

FIG. 3C is a flow chart of an embodiment method that may be performed by the embodiment resonating structure of FIG. 3A;

FIG. 4A is a side view of another embodiment resonant structure;

FIG. 4B is a schematic diagram of the resonant structure of the embodiment of FIG. 4A;

FIG. 4C is a flow chart of an embodiment method that may be performed by the embodiment resonating structure of FIG. 4A;

FIG. 5A is a side view of another embodiment resonant structure;

FIG. 5B is a schematic diagram of the resonant structure of the embodiment of FIG. 5A;

FIG. 5C is a flow chart of an embodiment method that may be performed by the embodiment resonating structure of FIG. 5A;

FIG. 6A is a side view of another embodiment resonant structure;

FIG. 6B is a schematic diagram of the resonant structure of the embodiment of FIG. 6A;

FIG. 6C is a flow chart of an embodiment method that may be performed by the embodiment resonating structure of FIG. 6A;

FIG. 7A is a side view of another embodiment resonant structure;

FIG. 7B is an example ring structure that may be disposed in the resonant structure of FIG. 7A;

FIG. 7C is a schematic diagram of the resonant structure of the embodiment of FIG. 7A;

FIG. 7D is a flow chart of an embodiment method that may be performed by the embodiment resonating structure of FIG. 7A;

FIG. 8A is a side view of another embodiment resonant structure;

FIG. 8B is a schematic diagram of the resonant structure of the embodiment of FIG. 8A;

FIG. 8C is a flow chart of an embodiment method that may be performed by the embodiment resonating structure of FIG. 8A;

FIG. 9A is a side view of another embodiment resonant structure;

FIG. 9B is a schematic diagram of the resonant structure of the embodiment of FIG. 9A;

FIG. 9C is a flow chart of an embodiment method that may be performed by the resonant circuit of the resonant structure of FIG. 9A;

FIG. 10A is a side view of another embodiment resonant structure;

FIG. 10B is a schematic diagram of the resonant structure of the embodiment of FIG. 10A;

FIG. 10C is a flow chart of an embodiment method that may be performed by the resonant circuit of the resonant structure of FIG. 10A;

FIG. 11A is a side view of another embodiment resonant structure;

FIG. 11B is a schematic diagram of the resonant structure of the embodiment of FIG. 11A;

FIG. 11C is a flow chart of an embodiment method that may be performed by the resonant circuit of the resonant structure of FIG. 11A;

FIG. 12 is a top view of an embodiment radiating structure; and

FIG. 13A is a side view of another embodiment resonant structure;

FIG. 13B is a schematic diagram of the resonant structure of the embodiment of FIG. 13A;

FIG. 13C is a flow chart of an embodiment method that may be performed by the internal resonant circuit of the resonant structure of FIG. 13A;

FIG. 13D is a flow chart of an embodiment method that may be performed by an external resonant circuit of the resonant structure of FIG. 13A; and

fig. 14 is a top view of another embodiment radiating structure.

Detailed Description

The present disclosure provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments are merely illustrative of specific 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.

Variations or modifications described in relation to one of these embodiments may also be applied to the other embodiments. Further, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the disclosure as defined by the appended claims.

Although aspects of the present invention are described primarily in the context of a resonant structure in a plasma processing system, aspects of the present invention may be similarly applied to fields other than the semiconductor industry. The plasma can be used to treat and modify surface properties by adding functional groups. For example, to treat paint deposition of a surface, the plasma may convert a hydrophobic surface to a hydrophilic surface. Further, aspects of the invention are not limited to plasmas. For example, RF can be used to defrost frozen food or to dry textiles, food, wood, and the like. In these different examples, and in various industries, a uniform oscillating magnetic field as disclosed herein is advantageous.

In various embodiments, reference to a magnetic field refers to a magnetic field that oscillates at a frequency (e.g., at one of RF or microwave frequencies). In these embodiments, the magnetic field does not refer to a DC magnetic field. These and other details are discussed in more detail below.

Fig. 1 illustrates a block diagram of an embodiment plasma processing system 100. 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 fig. 1. Further, plasma processing system 100 may include additional components not depicted in fig. 1.

In an embodiment, RF source 102 comprises an RF power source, 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, etc.). The RF source provides forward RF waves 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 propagates (i.e., radiates) toward the plasma chamber 106.

The plasma chamber 106 includes a substrate holder 108. As shown, the 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 to remove byproducts from the plasma chamber by selectively controlling the flow rate of gas within the plasma chamber 106. In an embodiment, the pump outlet 116 is positioned near (e.g., below/around) the substrate holder 108 and the substrate 110.

In an embodiment, the resonant structure 104 is spaced apart from the plasma chamber 106 by a dielectric plate 114 made of a dielectric material. The dielectric plate 114 separates the low pressure environment within the plasma chamber 106 from the external atmosphere. It should be appreciated that the resonant structure 104 can be placed directly adjacent to the plasma chamber 106 or the resonant structure 104 can be spaced 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 other embodiments, the resonant structure 104 is embedded within the dielectric plate 114.

In an embodiment, the resonant structure 104 radiates an electromagnetic field toward the plasma chamber 106, producing an azimuthally symmetric, high density plasma 112 with a low capacitively coupled electric field. In an embodiment, the resonant structure 104 includes a spiral arm connected to a capacitive structure that creates azimuthal symmetry, as disclosed herein. In an embodiment, the excitation frequency of the resonant structure 104 is in the radio frequency range (10 to 400 MHz), which is not limiting, and other frequency ranges are also contemplated. For example, aspects of the invention disclosed herein are equally applicable to applications in the microwave frequency range.

In an embodiment, the resonant structure 104 comprises a resonant element. The resonant element may be a spiral arm of a capacitive structure electrically connected to the resonant structure 104. In an embodiment, the resonant elements have the same shape and are arranged around the central axis such that there is N-fold symmetry when rotating, where N is an integer greater than 1. The spiral arms and capacitive structures resonate with electromagnetic waves fed from the RF source 102.

In an embodiment, the resonant element maintains standing wave electromagnetic waves. The standing wave electromagnetic wave has a region of high electric field and other regions of high magnetic field. The region of high magnetic field is composed of conductive paths. The resonant elements are placed close to and parallel to the dielectric plate 114 such that the oscillating magnetic field from the resonant elements penetrates into the plasma chamber 106. The time-varying magnetic field induces a time-varying electric field that imparts energy to the plasma electrons.

In an embodiment, the resonant structure 104 includes a region of high electric field-located away from the dielectric plate 114. In an embodiment, such regions consist of a metal structure with a planar surface. In an embodiment, the planar surfaces of the two metal pieces are opposite and are separated by a dielectric plate. The volume between the two metallic pieces occupied by the dielectric plate is the location of the high electric field in the corresponding resonant circuit of the resonant structure 104.

In other embodiments, the metallic piece may have a cylindrical shape or other geometric shape. In all cases, the two metal surfaces are separated by a region filled with dielectric material (which may also be air or vacuum).

The magnetic field in the high magnetic field elements is generated by the current flowing along these elements. The electric field in the high field element is generated by the presence of electric charges. The element having a high electric field is connected to other such high electric field elements by an element having a high magnetic field such that charge flows from one region of the high electric field to another region of the high electric field by a current, thereby generating a magnetic field in the high magnetic field element.

In an embodiment, the high electric field elements may also be connected to each other in such a way that the electric fields in the resonant structure 104 are in phase and have the same amplitude. However, this feature is non-limiting.

In an embodiment, the high magnetic field element and the high electric field element are all substantially identical to each other.

In an embodiment, the high magnetic field elements of the resonant structure 104 and the high electric field elements of the resonant structure 104 are arranged around a central symmetry axis. In an embodiment, the central symmetry axis is perpendicular to the dielectric plate 114. In embodiments where the dielectric plate 114 is disk-shaped, the central axis of symmetry passes through the center of the disk. The elements of the resonant structure 104 are arranged such that the geometry is unchanged when all the elements are rotated around the symmetry axis by an angle equal to 2pi divided by an integer greater than 2. In an embodiment with an eight-fold symmetry arrangement, the corresponding integer is equal to 8.

In an embodiment, the RF source 102 couples energy to an interface of the resonant structure 104 to generate standing wave electromagnetic waves from the resonant structure 104. In an embodiment, the RF source 102 is coupled to the interface via a transmission line. It is desirable that the interface maintain the same or higher symmetry with the elements of the resonant structure 104 while rotating about the axis of symmetry.

In an embodiment, the interface couples energy to the high electric field portion of the resonant structure 104—capacitive coupling. In an embodiment, the interface couples energy to the high magnetic field portion of the resonant structure 104—inductive coupling. In both cases, the interface may be arranged such that the electromagnetic field generated by the resonant structure 104 may penetrate into the plasma chamber 106, thereby self-generating the plasma 112.

In an embodiment, the resonant structure 104 couples RF power from the RF source 102 to the plasma chamber 106 to process the substrate 110. Specifically, the resonant structure 104 radiates electromagnetic waves in response to feeding forward RF waves from the RF source 102. The radiated electromagnetic waves penetrate into the plasma chamber 106 from the atmospheric side of the dielectric plate 114 (i.e., the side of the resonant structure 104). The radiated electromagnetic waves generate an electromagnetic field within the plasma chamber 106. The generated electromagnetic field ignites and maintains the plasma 112 by transferring energy to free electrons within the plasma chamber 106. Plasma 112 may be used, for example, to selectively etch or deposit material on substrate 110.

In fig. 1, the resonant structure 104 is shown outside of the plasma chamber 106. However, in an embodiment, the resonant structure 104 can be placed inside the plasma chamber 106.

In an embodiment, the resonant structure 104 operates at a frequency 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), which range is determined by various factors such as distance from the resonant structure 104, impedance value, etc.

Fig. 2A shows a side view of an embodiment resonant structure 200. The resonant structure 200 includes an interface 206, a radiating structure 222, conductive offsets 224a-b, which may or may not be arranged as shown in fig. 2 a. Further, the resonant structure 200 can include additional components not depicted in fig. 2A.

Radiating structure 222 is coupled to interface 206 by conductive offsets 224 a-b. The radiating structure 222 is coupled to the RF source 102 through a capacitive voltage divider, as described in detail below. Details about the radiating structure 222 are disclosed herein below in fig. 12.

Additionally, fig. 2A also shows shells 226a-c surrounding the resonant structure 200. The housing 226a-c includes a housing sidewall 226a, a housing bottom side 226b, and a housing top side 226c. Each of the housing sidewall 226a and the housing bottom side 226b is a conductive structure. The housing top side 226c is shown in phantom to represent the open surfaces of the housings 226a-c.

The housing bottom side 226b is electrically coupled to a common RF ground of the RF source 102. Thus, the entire housing 226a-c is grounded. The housing bottom side 226b includes an opening to couple the RF feed path from the RF source 102 to the interface 206 (i.e., the drive disk 202 described in detail below).

In an embodiment, the housing top side 226c is positioned adjacent to the bottom of the plasma chamber 106. Referring to fig. 1, the resonant structure 200 is flipped up and down and the housing top side 226c of the resonant structure 200 is positioned such that the dielectric plate 114 is flush with the housing top side 226c. In such an embodiment, the dielectric plate 114 is located above the radiating structure 222 in the direction of the housing top side 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 side 226b to the housing top side 226c.

Resonant structure 200 can operate as resonant structure 104 in plasma processing system 100 in fig. 1. Note that the resonant structure 200 is not limited to application in plasma processing, as other applications are also contemplated. Further, the resonant structure 200 may include additional components not depicted in fig. 2A, such as a non-conductive offset, to provide additional structural rigidity to the resonant structure 200 by mechanically connecting the radiating structure 222 to the interface 206.

Interface 206 includes drive disk 202, back plate 208, inner ring 210, outer ring 212, and insulating structure 214.

The drive plate 202 is a circular conductive structure that is coupleable to the RF source 102 and is used to provide RF waves to the radiating structure 222. In an embodiment, the drive disk 202 is coupled to the RF source 102 via a rigid, semi-rigid, or flexible coaxial cable. In other embodiments, the drive disk 202 is coupled to an RF or microwave generator via any of a variety of types of transmission lines, such as a rectangular waveguide, two parallel conductive strips (e.g., triaxial cable) with two cylindrical conductors contained within a larger hollow cylinder, etc.

The back plate 208 is a conductive surface disposed between the RF source 102 and the drive disk 202. The back plate 208 is substantially parallel to the drive disk 202. As shown, the back plate 208 is floating.

The inner ring 210 and the outer ring 212 are conductive structures. As shown, the outer ring 212 is disposed adjacent to the inner ring 210 and lies substantially in the same plane. However, in embodiments, the outer ring 212 may lie in a different plane than the inner ring 210.

The outer ring 212 and the inner ring 210 are annular conductive plates having an inner radius and an outer radius. The outer ring 212 and the inner ring 210 have the same center point as the drive disk 202. And, the inner radius of the outer ring 212 is greater than the outer radius of the inner ring 210. The inner radius of the inner ring 210 is smaller than the outer radius of the drive disk 202.

Because fig. 2A shows a side view of the resonant structure 200, it should be understood that in an embodiment, there is an axis of symmetry at the center of the resonant structure 200. In an embodiment, the resonant structure 200 has a cylindrical structure. In these embodiments, for example, the portion of the outer ring 212 shown on the left side of the drive disk 202 and the portion of the outer ring 212 shown on the right side of the drive disk 202 are part of the same conductive ring structure. Further, other components of the resonant structure 200 (such as the inner ring 210, the radiating structure 222, the backplate 208, etc.) have similar symmetry with respect to the center of the resonant structure.

The insulating structure 214 is comprised of an electrically insulating material (e.g., dielectric material, etc.). In an embodiment, the insulating structure 214 is comprised of air or vacuum. The insulating structure 214 is disposed between the drive disk 202 and the inner ring 210, between the back plate 208 and the inner ring 210, between the inner ring 210 and the outer ring 212, and between the back plate 208 and the outer ring 212.

In an embodiment, the interface 206 is embedded in an insulating medium, such as air or a dielectric (i.e., the insulating structure 214). Although the arrows designating the insulating structure 214 are shown as pointing to the area of the interface 206 in fig. 2A-more properly the volume, it should be understood that the arrows are intended to imply that the insulating structure 214 covers the area or volume around the different conductive and non-conductive materials of the resonant structure 200.

In an embodiment, the insulating structure 214 may comprise a plurality of insulating structures, effectively forming a single insulating structure between the various conductive components of the interface 206. In other embodiments, the insulating structure 214 may be a single insulating structure formed between the various conductive components of the interface 206.

As shown, the conductive offsets 224a-b are arranged perpendicular to the inner ring 210, the outer ring 212, and the radiating structure 222. However, the conductive offsets 224a-b may also be arranged to connect the inner ring 210 and the outer ring 212 perpendicularly to the radiating structure 222, rather than perpendicularly to these surfaces.

As shown, the conductive offsets 224a-b include an inner conductive offset group 224a and an outer conductive offset group 224b. The inner conductive offset set 224a electrically couples the inner ring 210 to the interior of the radiating structure 222. The outer conductive offset set 224b electrically couples the outer ring 212 to the exterior of the radiating structure 222.

In an embodiment, the ends of each of the inner conductive offset groups 224a are disposed equidistant from each other along the surface of the inner ring 210.

In an embodiment, the ends of each of the outer conductive offset groups 224a are disposed equidistant from each other along the surface of the outer ring 212.

Fig. 2B shows a schematic diagram 240 of the embodiment resonant structure 200 of fig. 2A, also referred to as a dual floating capacitor configuration. Schematic 240 includes RF source 102, capacitor 242, capacitor 244, capacitor 246, capacitor 248, capacitor 249, and inductor 250, which may (or may not) be arranged as shown in fig. 2B. Here, the RF source 102 is shown as an AC power source. In an embodiment, the RF source 102 is configured to provide a forward RF wave to the resonant circuit 252.

The capacitor 242 is formed by the drive plate 202, the insulating structure 214, and the inner ring 210. The drive plate 202 and the inner ring 210 are conductive plates arranged parallel to each other, sandwiching an insulating structure 214 therebetween, forming a parallel plate capacitor. The drive disk 202 is capacitively coupled to the inner ring 210 as shown by capacitor 242.

The capacitor 244 (i.e., an internal capacitor) is formed by the backplate 208, the insulating structure 214, and the inner ring 210. The back plate 208 and the inner ring 210 are parallel arranged conductive plates sandwiching an insulating structure 214 therebetween, forming a parallel plate capacitor. In an embodiment, the capacitance value of capacitor 244 is greater than 10 micro-farads (pF). The capacitance value at each location of the parallel plate capacitor is substantially the same.

The capacitor 246 (i.e., the external capacitor) is formed by the backplate 208, the insulating structure 214, and the outer ring 212. The back plate 208 and the outer ring 212 are parallel arranged conductive plates sandwiching an insulating structure 214 therebetween, forming a parallel plate capacitor. In an embodiment, the capacitance value of capacitor 246 is greater than 10 micro-farads (pF). The capacitance value at each location of the parallel plate capacitor is substantially the same.

The capacitor 248 is formed by the housing bottom side 226b, the insulating structure 214, and the backplate 208. The housing bottom side 226b and the back plate 208 are parallel arranged conductive plates sandwiching the insulating structure 214 therebetween, forming a parallel plate capacitor.

The capacitor 249 is formed by the housing bottom side 226b, the insulating structure 214, and the inner ring 210. The housing bottom side 226b and the inner ring 210 are parallel arranged conductive plates sandwiching the insulating structure 214 therebetween, forming a parallel plate capacitor.

A first node of the capacitor 242 may be coupled to the RF source 102 via the drive plate 202. The first node of capacitor 248 is coupled to the first node of capacitor 244 and the first node of capacitor 246 via back plate 208. The second node of capacitor 248 and the first node of capacitor 249 are coupled to a common RF ground 262 via housing bottom side 226 b.

The inductor 250 is formed by the radiating structure 222. The first node of inductor 250 is coupled to the second node of capacitor 244, the second node of capacitor 242, and the second node of capacitor 249 via inner conductive offset group 224a and inner loop 210. A second node of inductor 250 is coupled to a second node of capacitor 246 via outer conductive offset group 224b and outer loop 212.

In an embodiment, the inductor 250 is formed by a conductive portion of the radiating structure 222 along which there is a phase shift of the electromagnetic wave propagating, the sign of which coincides with the phase change of an ideal lumped circuit inductor.

In an embodiment, the RF source 102 is electromagnetically coupled to each of the inner ring 210 and the back plate 208 via the drive disk 202.

Inductor 250, capacitor 244, and capacitor 246 form a resonant circuit 252 (i.e., LC resonant circuit). With respect to fig. 2A, the inner ring 210, the inner set of conductive offsets 224a, the radiating structure 222, the outer set of conductive offsets 224b, the outer ring 212, the backplate 208, and the insulating structure 214 form a resonant circuit 252. In this arrangement, there is no Direct Current (DC) connection between any portion of the resonant circuit 252 and the common RF ground.

The various electrical and mechanical parameters of the structural components forming the inductors and capacitors of the resonant structure 200 are selected such that the resonant structure 200 operates at a desired operating frequency (i.e., resonates).

In an embodiment, capacitor 244 and capacitor 246 provide a low impedance path to resonant circuit 252 (and in particular to elements of radiating structure 222). In an embodiment, the radiating structure 222 includes a plurality of spiral arms (described in detail in fig. 12 below). Each spiral arm is connected to the inner ring 210 via the conductive offset of the inner conductive offset set 224a on the inner end of the spiral arm and to the outer ring 212 via the conductive offset of the outer conductive offset set 224b on the outer end of the spiral arm.

The spiral arms are connected to each other by an inner ring 210 and an outer ring 212. The inner ring 210 and the outer ring 212 form a low impedance path at the frequency of interest such that the voltage difference across each spiral arm is substantially the same. The resulting structure prevents current from concentrating in a subset of the elements of radiating structure 222, and thus symmetry between the elements of radiating structure 222 is improved. Thus, this arrangement prevents nonlinear effects from concentrating plasma 112 in a spiral subset.

Fig. 2C illustrates a flow chart of an embodiment method 280 that may be performed by the resonant structure 200. At step 282, the RF source 102 provides a forward RF wave to the drive disk 202. In response, at step 284, RF waves are transmitted from the drive plate 202 to the radiating structure 222 (i.e., the inductor 250) through capacitive coupling between the capacitor 242, the capacitor 244, and the capacitor 246.

At step 286, the radiating structure 222 radiates electromagnetic waves from the resonant structure 200 into the plasma chamber 106. At step 288, the electromagnetic wave generates a plasma 112. In such embodiments, the plasma generated by the RF discharge is classified as a purely inductively coupled plasma.

Fig. 3A shows a side view of an embodiment resonant structure 300. Resonant structure 300 can operate as resonant structure 104 in plasma processing system 100 of fig. 1. Note that the resonant structure 300 is not limited to application in plasma processing, and other similar applications are also contemplated.

The resonant structure 300 shares several features with the resonant structure 200. However, in the interface 306 of the resonant structure 300, the backplate 208 of the resonant structure 200 is merged with the housing bottom side 226 b. Thus, in contrast to the resonant structure 200 of the floating backplate 208, in the resonant structure 300, the housing bottom side 226b (actually the backplate) is connected to a common RF ground.

Fig. 3B shows a schematic diagram 340 of the embodiment resonant structure 300 of fig. 3A, also referred to as a dual grounded capacitor configuration. Schematic 340 includes RF source 102, capacitor 242, capacitor 344, capacitor 346, and inductor 250, which may (or may not) be arranged as shown in fig. 3B.

The capacitor 242 is formed by the drive plate 202, the insulating structure 314 and the inner ring 210. The drive plate 202 and the inner ring 210 are conductive plates arranged parallel to each other, sandwiching an insulating structure 314 therebetween, forming a parallel plate capacitor. The drive disk 202 is capacitively coupled to the inner ring 210 as shown by capacitor 242.

The capacitor 344 (i.e., an internal capacitor) is formed by the housing bottom side 226b, the insulating structure 314, and the inner ring 210. The housing bottom side 226b and the inner ring 210 are parallel arranged conductive plates sandwiching an insulating structure 314 therebetween forming a parallel plate capacitor. In an embodiment, the capacitance value of capacitor 344 is greater than 10 micro-farads (pF). The capacitance value at each location of the parallel plate capacitor is substantially the same.

Capacitor 346 (i.e., an external capacitor) is formed by housing bottom side 226b, insulating structure 314, and outer ring 212. The housing bottom side 226b and the outer ring 212 are parallel arranged conductive plates sandwiching an insulating structure 314 therebetween forming a parallel plate capacitor. In an embodiment, the capacitance value of capacitor 346 is greater than 10 micro-farads (pF). The capacitance value at each location of the parallel plate capacitor is substantially the same.

A first node of the capacitor 242 may be coupled to the RF source 102 via the drive plate 202. A first node of capacitor 344 and a first node of capacitor 346 are coupled to common RF ground 262 via housing bottom side 226 b.

The inductor 250 is formed by the radiating structure 222. A first node of inductor 250 is coupled to a second node of capacitor 242 and a second node of capacitor 344 via inner conductive offset group 224a and inner loop 210. A second node of inductor 250 is coupled to a second node of capacitor 346 via outer conductive offset group 224b and outer ring 212.

In an embodiment, the RF source 102 is electromagnetically coupled to the inner ring 210 via the drive plate 202.

Inductor 250, capacitor 344, and capacitor 346 form a resonant circuit 352 (i.e., LC resonant circuit). With respect to fig. 3A, inner ring 210, inner set of conductive offsets 224a, radiating structure 222, outer set of conductive offsets 224b, outer ring 212, housing bottom side 226b, and insulating structure 314 form a resonant circuit 352.

The various electrical and mechanical parameters of the structural components forming the inductors and capacitors of the resonant structure 300 are selected such that the resonant structure 300 operates at a desired operating frequency (i.e., resonates).

Fig. 3C illustrates a flow chart of an embodiment method 380 that may be performed by the resonant structure 300. At step 382, the RF source 102 provides a forward RF wave to the drive disk 202. In response, at step 384, RF waves are transmitted from the drive plate 202 to the radiating structure 222 (i.e., the inductor 250) through capacitive coupling between the capacitor 242, the capacitor 344, and the capacitor 346.

At step 386, the radiating structure 222 radiates electromagnetic waves from the resonant structure 300 to the plasma chamber 106. At step 388, the electromagnetic waves generate plasma 112. In such embodiments, the plasma generated by the RF discharge is classified as a purely inductively coupled plasma.

Fig. 4A shows a side view of an embodiment resonating structure 400. Resonant structure 400 can operate as resonant structure 104 in plasma processing system 100 in fig. 1. Note that the resonant structure 400 is not limited to application in plasma processing, and other applications are also contemplated.

Resonant structure 400 shares several features with resonant structure 200. In contrast to the resonant structure 200 where the insulating structure 214 is disposed between the backplate 208 and the outer ring 212 in the interface 206, in the resonant structure 400, the corresponding backplate 208 and outer ring 212 of the resonant structure 200 are directly (i.e., electrically and mechanically) coupled—represented by the backplate 408 in fig. 4A. The outer conductive offset set 224b electrically and mechanically couples the radiating structure 222 to the backplate 408.

Fig. 4B shows a schematic diagram 440 of the embodiment resonant structure 400 of fig. 4A, also referred to as a single floating capacitor configuration. Schematic 440 includes RF source 102, capacitor 442, capacitor 444, capacitor 448, capacitor 449, and inductor 250, which may (or may not) be arranged as shown in fig. 4B.

Capacitor 442 is formed by drive plate 202, insulating structure 414, and inner ring 210. The drive plate 202 and the inner ring 210 are conductive plates arranged parallel to each other, sandwiching an insulating structure 414 therebetween, forming a parallel plate capacitor. The drive plate 202 is capacitively coupled to the inner ring 210 as shown by capacitor 442.

The capacitor 444 (i.e., the internal capacitor) is formed by the backplate 408, the insulating structure 414, and the inner ring 210. The back plate 408 and the inner ring 210 are parallel arranged conductive plates sandwiching an insulating structure 414 therebetween, forming a parallel plate capacitor. In an embodiment, the capacitance value of capacitor 444 is greater than 10 picofarads (pF). The capacitance value at each location of the parallel plate capacitor is substantially the same.

The capacitor 448 is formed by the housing bottom side 226b, the insulating structure 414, and the backplate 408. The housing bottom side 226b and the back plate 408 are parallel arranged conductive plates sandwiching an insulating structure 414 therebetween forming a parallel plate capacitor.

Capacitor 449 is formed by housing bottom side 226b, insulating structure 414 and inner ring 210. The housing bottom side 226b and the inner ring 210 are parallel arranged conductive plates sandwiching an insulating structure 414 therebetween forming a parallel plate capacitor.

A first node of the capacitor 442 may be coupled to the RF source 102 via the drive plate 202. A first node of the capacitor 448 is coupled to a first node of the capacitor 444 via the backplate 408. The second node of capacitor 448 and the first node of capacitor 449 are coupled to the common RF ground 262 via the housing bottom side 226 b.

The inductor 250 is formed by the radiating structure 222. The first node of inductor 250 is coupled to the second node of capacitor 444, the second node of capacitor 442, and the second node of capacitor 449 via inner conductive offset group 224a and inner loop 210. A second node of the inductor 250 is coupled to a first node of the capacitor 448 and a second node of the capacitor 444 via the external conductive offset group 224b and the backplate 408.

Inductor 250 and capacitor 444 form a resonant circuit 452 (i.e., LC resonant circuit). With respect to fig. 4A, inner ring 210, inner set of conductive offsets 224A, radiating structure 222, outer set of conductive offsets 224b, backplate 408, and insulating structure 414 form a resonant circuit 452. In this arrangement, there is no Direct Current (DC) connection between any portion of resonant circuit 452 and common RF ground.

The various electrical and mechanical parameters of the structural components forming the inductors and capacitors of the resonant structure 400 are selected such that the resonant structure 400 operates at a desired operating frequency (i.e., resonates).

Fig. 4C illustrates a flow chart of an embodiment method 480 that may be performed by the resonant structure 400. At step 482, the RF source 102 provides a forward RF wave to the drive disk 202. In response, at step 484, RF waves are transmitted from drive disk 202 to radiating structure 222 (i.e., inductor 250) through capacitive coupling between capacitor 442 and capacitor 444.

At step 486, the radiating structure 222 radiates electromagnetic waves from the resonant structure 400 to the plasma chamber 106. At step 488, the electromagnetic wave generates plasma 112. In such embodiments, the plasma generated by the RF discharge is classified as a purely inductively coupled plasma.

Fig. 5A shows a side view of an embodiment resonating structure 500. Resonant structure 500 can operate as resonant structure 104 in plasma processing system 100 of fig. 1. Note that the resonant structure 500 is not limited to application in plasma processing, and other similar applications are also contemplated.

Resonant structure 500 shares several features with resonant structure 400. However, in the interface 506 of the resonant structure 500, the backplate 208 of the resonant structure 400 is merged with the housing bottom side 226 b. Thus, in contrast to the resonant structure 400 of the floating backplate 208, in the resonant structure 500, the housing bottom side 226b (actually the backplate) is connected to a common RF ground.

Fig. 5B shows a schematic diagram 540 of the embodiment resonant structure 500 of fig. 5A, also referred to as a single grounded capacitor configuration. Schematic 540 includes RF source 102, capacitor 542, capacitor 544, and inductor 250, which may or may not be arranged as shown in fig. 5B.

The capacitor 542 is formed by the drive plate 202, the insulating structure 514, and the inner ring 210. The drive plate 202 and the inner ring 210 are conductive plates arranged parallel to each other, sandwiching an insulating structure 514 therebetween, forming a parallel plate capacitor. The drive plate 202 is capacitively coupled to the inner ring 210 as shown by capacitor 542. A first node of the capacitor 542 may be coupled to the RF source 102 via the drive plate 202.

The capacitor 544 (i.e., an internal capacitor) is formed by the housing bottom side 226b, the insulating structure 514, and the inner ring 210. The housing bottom side 226b and the inner ring 210 are parallel arranged conductive plates sandwiching an insulating structure 514 therebetween forming a parallel plate capacitor. In an embodiment, the capacitance value of capacitor 544 is greater than 10 micro-farads (pF). The capacitance value at each location of the parallel plate capacitor is substantially the same.

The inductor 250 is formed by the radiating structure 222. The first node of inductor 250 is coupled to a first node of capacitor 544 and a second node of capacitor 542 via inner conductive offset set 224a and inner loop 210. A second node of the inductor 250 is coupled to a second node of the capacitor 544 and the common RF ground 262 via the external conductive offset group 224b and the housing bottom side 226 b.

Inductor 250 and capacitor 544 form a resonant circuit 552 (i.e., LC resonant circuit). With respect to fig. 5A, inner ring 210, inner set of conductive offsets 224a, radiating structure 222, outer set of conductive offsets 224b, housing bottom side 226b, and insulating structure 514 form resonant circuit 552.

The various electrical and mechanical parameters of the structural components forming the inductors and capacitors of the resonant structure 500 are selected such that the resonant structure 500 operates at a desired operating frequency (i.e., resonates).

Fig. 5C illustrates a flow chart of an embodiment method 580 that may be performed by the resonant structure 500. At step 582, the RF source 102 provides a forward RF wave to the drive disk 202. In response, at step 584, RF waves are transmitted from the drive disk 202 to the radiating structure 222 (i.e., the inductor 250) through capacitive coupling between the capacitor 542 and the capacitor 544.

At step 586, the radiating structure 222 radiates electromagnetic waves from the resonant structure 500 into the plasma chamber 106. At step 588, electromagnetic waves generate plasma 112. In such embodiments, the plasma generated by the RF discharge is classified as a purely inductively coupled plasma.

Fig. 6A shows a side view of an embodiment resonant structure 600. Resonant structure 600 can operate as resonant structure 104 in plasma processing system 100 in fig. 1. Note that resonant structure 600 is not limited to application in plasma processing, and other applications are also contemplated.

The resonant structure 600 shares several features with the resonant structure 200. In contrast to the resonant structure 200 where the insulating structure 214 is arranged between the backplate 208 and the inner ring 210 in the interface 206, in the resonant structure 600 the corresponding backplate 208 and inner ring 210 of the resonant structure 200 are directly (i.e. electrically and mechanically) coupled-represented by backplate 608 in fig. 6A. The inner set of conductive offsets 224a electrically and mechanically couple the radiating structure 222 to the backplate 608.

In addition, in addition to the drive disk 202, the resonant structure 600 also includes an extended drive disk 602 electrically coupled to the drive disk 202 (represented by black lines). In an embodiment, the drive disk 202 is electrically coupled to the expansion drive disk 602 via wire bonds. In some embodiments, the drive disk 202 is electrically coupled to the expansion drive disk 602 via ribbon bonding. In other embodiments, the drive disk 202 is electrically and mechanically coupled to the expansion drive disk 602 via rigid horizontal conductive pins or arms. Thus, RF waves generated by the RF source 102 are transmitted from the drive disk 202 to the expansion drive disk 602.

Fig. 6B shows a schematic diagram 640 of the embodiment resonant structure 600 of fig. 6A. Schematic 640 includes RF source 102, capacitor 642, capacitor 646, capacitor 648, capacitor 649, and inductor 250, which may (or may not) be arranged as shown in fig. 6B.

The capacitor 642 is formed by the expansion drive disk 602, the insulating structure 614, and the backplate 608. The expansion drive disk 602 and the backplate 608 are conductive plates arranged parallel to each other, sandwiching an insulating structure 614 therebetween, forming a parallel plate capacitor. The expansion drive disk 602 is capacitively coupled to the backplate 608, as shown by capacitor 642. A first node of the capacitor 642 may be coupled to the RF source 102 via the drive plate 202 and the extension drive plate 602.

Capacitor 646 (i.e., an external capacitor) is formed by backplate 608, insulating structure 614, and outer ring 212. The backplate 608 and the outer ring 212 are parallel arranged conductive plates sandwiching an insulating structure 614 therebetween, forming a parallel plate capacitor. In an embodiment, the capacitance of capacitor 646 is greater than 10 picofarads (pF). The capacitance value at each location of the parallel plate capacitor is substantially the same.

Capacitor 648 is formed from housing bottom side 226b, insulating structure 6414 and outer ring 212. The housing bottom side 226b and the outer ring 212 are parallel arranged conductive plates sandwiching an insulating structure 614 therebetween forming a parallel plate capacitor.

The capacitor 649 is formed by the housing bottom side 226b, the insulating structure 614, and the backplate 608. The housing bottom side 226b and the backplate 608 are parallel arranged conductive plates sandwiching an insulating structure 614 therebetween forming a parallel plate capacitor. A first node of capacitor 648 and a first node of capacitor 649 are coupled to the common RF ground 262.

The inductor 250 is formed by the radiating structure 222. The first node of inductor 250 is coupled to the first node of capacitor 642, the first node of capacitor 646, and the first node of capacitor 649 via the internal conductive offset group 224a and backplate 608. A second node of inductor 250 is coupled to a second node of capacitor 646 and a second node of capacitor 648 via outer conductive offset group 224b and outer ring 212.

Inductor 250 and capacitor 646 form a resonant circuit 652 (i.e., an LC resonant circuit). With respect to fig. 6A, outer ring 212, inner set of conductive offsets 224a, radiating structure 222, outer set of conductive offsets 224b, backplate 608, and insulating structure 614 form resonant circuit 652. In this arrangement, there is no Direct Current (DC) connection between any portion of the resonant circuit 652 and the common RF ground.

The various electrical and mechanical parameters of the structural components forming the inductors and capacitors of the resonant structure 600 are selected such that the resonant structure 600 operates/resonates at a desired operating frequency.

Fig. 6C illustrates a flow chart of an embodiment method 680 that may be performed by the resonant structure 600. At step 682, the RF source 102 provides a forward RF wave to the drive disk 202 and the expansion drive disk 602. In response, at step 684, RF waves are transmitted from the expansion drive disk 602 to the radiating structure 222 (i.e., the inductor 250) through capacitive coupling between the capacitor 642 and the capacitor 646.

At step 686, the radiating structure 222 radiates electromagnetic waves from the resonant structure 600 into the plasma chamber 106. At step 688, electromagnetic waves generate plasma 112. In such embodiments, the plasma generated by the RF discharge is classified as a purely inductively coupled plasma.

Fig. 7A shows a side view of an embodiment resonating structure 700. Resonant structure 700 can operate as resonant structure 104 in plasma processing system 100 in fig. 1. Note that the resonant structure 700 is not limited to applications in plasma processing, as other applications are also contemplated.

The resonant structure 700 shares several features with the resonant structure 200. The resonant structure 700 does not include the drive disk 202 of the resonant structure discussed in fig. 2A, 3A, 4A, 5A, and 6A. In contrast, the resonant structure 700 includes a ring structure 702. In the resonant structure 700, the radiating structure 222 is coupled to the RF source 102 through an inductive voltage divider, as described further below.

It should be understood that features from the different embodiments previously described (and described later) may be combined to form other embodiments having the annular structure 702 instead of the drive disk 202 unless otherwise indicated. And variations or modifications described in one of these embodiments may be applied to the other embodiments as well. The statements are not limiting and features from any embodiment may be used in other embodiments.

Fig. 7B illustrates an embodiment ring structure 702 that may be disposed in a resonant structure 700. The annular structure 702 is a circular open conductive ring structure having a first end 712 and a second end 716. The first end 712 is coupled to the RF source 102 and is used to couple RF power to the radiating structure 222. The second end 716 of the ring structure 702 is coupled to the common RF ground of the resonant structure 700 and the RF source 102.

The center point of the annular structure 702 intersects the center point of the radiating structure 222. The radius of the annular structure 702 is smaller than the inner radius of the radiating structure 222 such that the annular structure 702 is placed on the same plane as the radiating structure 222 and is arranged within the inner radius of the radiating structure.

Although the ring structure 702 in fig. 7A is shown as being located within the boundaries of the inner conductive offset group 224a, the radius and arrangement of the ring structure 702 in the resonant structure 700 is not limiting.

In an embodiment, the annular structure 702 is disposed between the inner set of conductive offsets 224a and the outer set of conductive offsets 224 b. In another embodiment, the annular structure 702 is disposed outside of the outer conductive offset group 224 b. In such an embodiment, the radius of the annular structure 702 is greater than the outer radius of the radiating structure 222. In yet another embodiment, the diameter of the annular structure 702 is less than the diameter of the inner conductive offset set 224 a. In such embodiments, the annular structure 702 may be on a different plane (e.g., above or below the plane of the radiating structure 222). In all embodiments, a non-conductive offset may be connected to the annular structure 702 to increase structural rigidity.

Fig. 7C shows a schematic diagram 720 of the resonant structure 700 of the embodiment of fig. 7A. Schematic 720 includes RF source 102, inductor 722, inductor 724, inductor 726, capacitor 728, capacitor 730, and capacitor 732, which may (or may not) be arranged as shown in fig. 7C.

Inductor 722 is formed from ring structure 702. The first node of the ring structure 702 is coupled to the RF source 102 via a first end 712. A second node of the ring structure 702 is coupled to the common RF ground of the resonant structure 700 and the RF source 102 via a second end 716.

The inductor 724 is formed by the radiating structure 222. The inductor 722 (i.e., the radiating structure 222) is inductively coupled to the inductor 724 in response to the RF source 102 transmitting forward RF waves to the first end 712 of the ring structure 702.

The inductor 726 is formed from the radiating structure 222. Although inductor 522 and inductor 524 are shown as separate components, a single inductor may also represent inductor 522 and inductor 524 as they represent radiating structure 222.

The capacitor 728 is formed by the backplate 208, the insulating structure 714, and the inner ring 210. The back plate 208 and the inner ring 210 are parallel arranged conductive plates sandwiching an insulating structure 714 therebetween, forming a parallel plate capacitor.

The capacitor 730 is formed by the backplate 208, the insulating structure 714, and the outer ring 212. The back plate 208 and the outer ring 212 are parallel arranged conductive plates sandwiching an insulating structure 714 therebetween, forming a parallel plate capacitor.

The capacitor 732 is formed from the housing bottom side 226b, the insulating structure 714, and the backplate 208. The back plate 208 and the housing bottom side 226b are parallel arranged conductive plates sandwiching an insulating structure 714 therebetween forming a parallel plate capacitor.

A first node of capacitor 732 is coupled to common RF ground 262 via housing bottom side 226 b. A second node of capacitor 732 is coupled to a first node of capacitor 730 and a first node of capacitor 728 via back plate 208.

The node of inductor 726 is coupled to a second node of capacitor 730 via outer conductive offset set 224b and outer loop 212.

The node of inductor 724 is coupled to a second node of capacitor 728 via inner conductive offset set 224a and inner loop 210.

Inductor 724, inductor 726, capacitor 728, and capacitor 730 form a resonant circuit 752 (i.e., LC resonant circuit). With respect to fig. 7A, the inner ring 210, the outer ring 212, the inner set of conductive offsets 224a, the radiating structure 222, the outer set of conductive offsets 224b, the backplate 208, and the insulating structure 714 form a resonant circuit 752. In this arrangement, there is no Direct Current (DC) connection between any portion of the resonant circuit 752 and the common RF ground.

The various electrical and mechanical parameters of the structural components forming the inductors and capacitors of the resonant structure 700 are selected such that the resonant structure 700 operates/resonates at a desired operating frequency.

Fig. 7D illustrates a flow chart of an embodiment method 760 that may be performed by the resonant structure 700. At step 762, the RF source 102 provides a forward RF wave to the annular structure 702 via the first end 712. In response, at step 764, the RF wave is transmitted from the ring structure 702 to the radiating structure 222 (i.e., the inductor 726) through inductive coupling between the inductor 722 and the inductor 724.

At step 766, the radiating structure 222 radiates electromagnetic waves from the resonant structure 700 to the plasma chamber 106. At step 768, electromagnetic waves generate plasma 112. In such embodiments, the plasma generated by the RF discharge is classified as a purely inductively coupled plasma.

Fig. 8A shows a side view of an embodiment resonating structure 800. Resonant structure 800 can operate as resonant structure 104 in plasma processing system 100 of fig. 1. Note that the resonant structure 800 is not limited to application in plasma processing, and other similar applications are also contemplated.

Resonant structure 800 shares several features with resonant structure 300. In the resonant structure 800, the drive disk 202 in the resonant structure 800 is positioned between the inner ring 210 and the housing bottom side 226 b. In this embodiment, the backplate 208 is incorporated into the housing bottom side 226b, similar to the resonant structure 300.

Fig. 8B shows a schematic 840 of the embodiment resonant structure 800 of fig. 8A, also referred to as a dual grounded capacitor configuration. Schematic 840 includes RF source 102, capacitor 844, capacitor 846, capacitor 848, and inductor 250, which may (or may not) be arranged as shown in fig. 8B.

The capacitor 842 (i.e., the internal capacitor) is formed by the drive plate 202, the insulating structure 814, and the inner ring 210. The drive plate 202 and the inner ring 210 are conductive plates arranged parallel to each other, sandwiching an insulating structure 814 therebetween, forming a parallel plate capacitor.

In an embodiment, the drive disk 202 may be capacitively coupled to the inner ring 210, as shown by capacitor 842.

The capacitor 844 (i.e., an external capacitor) is formed by the housing bottom side 226b, the insulating structure 814, and the outer ring 211. The housing bottom side 226b and the outer ring 212 are parallel arranged conductive plates sandwiching an insulating structure 814 therebetween forming a parallel plate capacitor. The first node of capacitor 844 is coupled to common RF ground 262 via housing bottom side 226 b.

The capacitor 846 is formed by the housing bottom side 226b, the insulating structure 814 and the drive disk 202. The housing bottom side 226b and the drive plate 202 are parallel arranged conductive plates sandwiching an insulating structure 814 therebetween forming a parallel plate capacitor. The first node of capacitor 846 is coupled to common RF ground 262 via housing bottom side 226 b.

The first node of the capacitor 842 and the second node of the capacitor 846 may be coupled to the RF source 102 via the drive plate 202.

The inductor 250 is formed by the radiating structure 222. A first node of inductor 250 is coupled to a second node of capacitor 842 via inner conductive offset group 224a and inner loop 210. A second node of inductor 250 is coupled to a second node of capacitor 844 via outer conductive offset set 224b and outer loop 212.

In an embodiment, RF source 102 is electromagnetically coupled to each of inner ring 210 and housing bottom side 226b via drive disk 202.

Inductor 250, capacitor 842, capacitor 844, and capacitor 846 form a resonant circuit 852 (i.e., LC resonant circuit). With respect to fig. 8A, the inner ring 210, the inner set of conductive offsets 224a, the radiating structure 222, the outer set of conductive offsets 224b, the outer ring 212, the housing bottom side 226b, and the insulating structure 814 form a resonant circuit 852.

In embodiments where resonant structure 800 is used for plasma processing, the plasma generated by the RF discharge is classified as a purely inductively coupled plasma.

The various electrical and mechanical parameters of the structural components forming the inductors and capacitors of the resonant structure 800 are selected such that the resonant structure 800 operates at a desired operating frequency (i.e., resonates). In an embodiment, the RF source 102 is configured to feed RF power to the resonant circuit 852.

Fig. 8C illustrates a flow chart of an embodiment method 860 that may be performed by the resonant structure 800. At step 862, the RF source 102 provides a forward RF wave to the drive disk 202. In response, at step 864, RF waves are transmitted from drive disk 202 to radiating structure 222 (i.e., inductor 250) through capacitive coupling between capacitors 842, 844, and 846.

At step 866, the radiating structure 222 radiates electromagnetic waves from the resonant structure 800 to the plasma chamber 106. At step 868, electromagnetic waves generate plasma 112. The plasma generated by the RF discharge is classified as a pure inductively coupled plasma.

Fig. 9A shows a side view of an embodiment resonant structure 900. In the resonant structure 900, the resonant structure 900 includes an outer non-conductive offset set 924 in place of the outer conductive offset set 224b of the resonant structure 700. The outer non-conductive offset groups 924 provide structural rigidity to the exterior of the radiating structure 222 by mechanically connecting the backplate 208 to the radiating structure 222. However, it should be understood that in an embodiment, the outer non-conductive offset group 924 may be omitted from the structure, and the portion of the radiating structure 222 shown connected to the outer non-conductive offset group 924 may be floating.

Fig. 9B shows a schematic 940 of the embodiment resonant structure 900 of fig. 9A. In addition to the components disclosed in diagram 720, diagram 940 also includes a distributed constant circuit 954, which may (or may not) be arranged as shown in fig. 9B. The distributed constant circuit 954 includes a plurality of inductors 926 and capacitors 930 formed by the spiral arms of the radiating structure 222 and the backplate 208. Although the spiral arms of the radiating structure 222 and the backplate 208 are not directly electrically connected, the spiral arms of the radiating structure 222 and the backplate 208 have a "weak" electrical coupling (i.e., capacitive coupling) -a non-negligible electrical coupling, which forms a distributed constant circuit 954. Capacitor 930 provides a small capacitance value that results in a gradual change in the voltage and current along the spiral arms of radiating structure 222-without lumped capacitance.

Inductor 724, inductor 726, capacitor 728, inductor 926, and capacitor 930 form a resonant circuit 952 (i.e., LC resonant circuit). With respect to fig. 9A, the inner ring 210, the inner set of conductive offsets 224a, the radiating structure 222, the outer set of conductive offsets 224b, the backplate 208, and the insulating structure 714 form a resonant circuit 952. In this arrangement, there is no Direct Current (DC) connection between any portion of the resonant circuit 952 and the common RF ground.

The various electrical and mechanical parameters of the structural components forming the inductors and capacitors of the resonant structure 900 are selected such that the resonant structure 900 operates/resonates at a desired operating frequency.

Fig. 9C illustrates a flow chart of an embodiment method 960 that may be performed by the resonant structure 900. At step 962, the RF source 102 provides a forward RF wave to the annular structure 702 via the first end 712. In response, at step 964, RF waves are transmitted from the ring structure 702 to the radiating structure 222 (i.e., inductor 726, inductor 926) through inductive coupling between the inductor 722 and the inductor 724.

At step 966, the radiating structure 222 radiates electromagnetic waves from the resonant structure 900 to the plasma chamber 106. At step 968, electromagnetic waves generate plasma 112. In such embodiments, the plasma generated by the RF discharge is classified as a purely inductively coupled plasma.

Fig. 10A shows a side view of an embodiment resonant structure 1000. In the resonant structure 1000, the resonant structure 1000 includes an inner non-conductive offset group 1024 in place of the inner conductive offset group 224a of the resonant structure 700. The inner non-conductive offset group 1024 will provide structural rigidity to the interior of the radiating structure 222 by mechanically connecting the backplate 208 to the radiating structure 222. However, it should be understood that in embodiments, the inner non-conductive offset group 1024 may be omitted from the structure, and the portion of the radiating structure 222 shown connected to the inner non-conductive offset group 1024 may be floating.

Fig. 10B shows a schematic 1040 of the embodiment resonant structure 1000 of fig. 10A. Similar to diagram 940, diagram 1040 includes a distributed constant circuit 1054. The distributed constant circuit 1054 includes a plurality of inductors 1026 and capacitors 1030 formed by the spiral arms of the radiating structure 222 and the backplate 208. Although the spiral arms of the radiating structure 222 and the backplate 208 are not directly electrically connected, the spiral arms of the radiating structure 222 and the backplate 208 have a "weak" electrical coupling (i.e., capacitive coupling) -a non-negligible electrical coupling, which forms a distributed constant circuit 1054. Capacitor 1030 provides a small capacitance value that results in a gradual change in the voltage and current along the spiral arms of radiating structure 222-without lumped capacitance.

Inductor 724, inductor 726, capacitor 728, inductor 1026, and capacitor 1030 form resonant circuit 1052 (i.e., LC resonant circuit). With respect to fig. 10A, inner ring 210, inner set of conductive offsets 224a, radiating structure 222, outer set of conductive offsets 224b, backplate 208, and insulating structure 714 form a resonant circuit 1052. In this arrangement, there is no Direct Current (DC) connection between any portion of the resonant circuit 1052 and the common RF ground.

The various electrical and mechanical parameters of the structural components forming the inductors and capacitors of the resonant structure 1000 are selected such that the resonant structure 1000 operates/resonates at a desired operating frequency.

Fig. 10C illustrates a flow chart of an embodiment method 1060 that may be performed by the resonant structure 1000. At step 1062, the RF source 102 provides a forward RF wave to the annular structure 702 via the first end 712. In response, at step 1064, the RF wave is transmitted from the ring structure 702 to the radiating structure 222 (i.e., inductor 726, inductor 1026) through inductive coupling between the inductor 722 and the inductor 724.

At step 1066, the radiating structure 222 radiates electromagnetic waves from the resonant structure 1000 into the plasma chamber 106. At step 1068, the electromagnetic wave generates a plasma 112. In such embodiments, the plasma generated by the RF discharge is classified as a purely inductively coupled plasma.

Fig. 11A shows a side view of an embodiment resonant structure 1100. Resonant structure 1100 can operate as resonant structure 104 in plasma processing system 100 of fig. 1. Note that the resonant structure 1100 is not limited to application in plasma processing, and other similar applications are also contemplated.

In the resonant structure 1100, the conductive structures forming the various capacitive plates are arranged perpendicular to the housing bottom side 226b, in contrast to the previous embodiments in which the conductive structures forming the various capacitive plates are arranged parallel to the housing bottom side 226 b.

The resonant structure 1100 includes a cylindrical structure 1102 and a cylindrical ring structure 1112.

The cylindrical structure 1102 is an electrically conductive hollow cylindrical structure having an open side near the housing top side 226c and a closed side near the housing bottom side 226 b. Further, the cylindrical structure 1102 includes a conductive wall 1104. The closed side of the cylindrical structure 1102 is electrically coupled to an RF source 102 that feeds RF waves to the conductive wall 1104. The inner hollow of the cylindrical structure 1102 is surrounded by an insulating structure 1114. In an embodiment, the interior hollow of the cylindrical structure 1102 is filled with air.

The cylindrical ring structure 1112 is an electrically conductive hollow cylindrical ring structure having an electrically conductive inner wall 1108 and an electrically conductive outer wall 1106. The top portion of the cylindrical ring structure 1112 includes a radiating structure 222. Thus, the conductive inner wall 1008 and the conductive outer wall 1106 are arranged in parallel but perpendicular to the radiating structure 222. The bottom portion of cylindrical ring structure 1112 is open and the inner hollow portion of cylindrical ring structure 1112 is surrounded by insulating structure 1114.

The inner ring of cylindrical ring structure 1112 surrounds cylindrical structure 1102 such that conductive inner wall 1108 of cylindrical ring structure 1112 is arranged parallel to conductive wall 1104 of cylindrical structure 1102. In an embodiment, insulating structure 1114 is disposed between conductive inner wall 1108 of cylindrical ring structure 1112 and conductive wall 1104 of cylindrical structure 1102.

The conductive outer wall 1106 is disposed parallel to the housing sidewall 226a. In an embodiment, insulating structure 1114 is disposed between conductive outer wall 1106 of cylindrical ring structure 1112 and housing sidewall 226a. The housing sidewall 226a and the housing bottom side 226b are electrically coupled to a common RF ground of the resonant structure 1100 and the RF source 102.

Finally, the housing 226a-c further includes a housing inner wall 226d that in combination with the housing bottom side 226b creates a hollow cylindrical shape and is arranged parallel to the conductive inner wall 1108. In an embodiment, insulating structure 1114 is disposed between conductive inner wall 1108 of cylindrical ring structure 1112 and housing inner wall 226 d.

It should be appreciated that the arrangement of structures coupling RF waves from the RF source 102 to the radiating structure 222 may be of various shapes and is therefore non-limiting. Further, while the RF source 102 is electrically coupled to the center of the resonant structure 1100 via the conductive wall 1104 of the cylindrical structure 1102, it should be appreciated that in embodiments the RF source 102 is electrically coupled to the cylindrical ring structure 1112, the cylindrical structure 1102, or a combination of both.

Fig. 11B shows a schematic diagram 1140 of the embodiment resonant structure 1100 of fig. 11A. Schematic 1140 includes RF source 102, capacitor 1142, capacitor 1144, capacitor 1146, capacitor 1148, and inductor 250, which may (or may not) be arranged as shown in fig. 11B.

The capacitor 1142 is formed by the conductive wall 1104 of the cylindrical structure 1102, the insulating structure 1114, and the housing inner wall 226 d. The conductive wall 1104 and the housing inner wall 226d of the cylindrical structure 1102 are conductive cylinders arranged concentrically with one another, sandwiching the insulating structure 1114 therebetween, forming a cylindrical capacitor. The conductive wall 1104 of the cylindrical structure 1102 is electrically coupled to the RF source 102. The housing inner wall 226d is electrically coupled to a common RF ground.

The capacitor 1144 is formed by the conductive wall 1104 of the cylindrical structure 1102, the insulating structure 1114, and the conductive inner wall 1108 of the cylindrical ring structure 1112. The conductive wall 1104 of the cylindrical structure 1102 and the conductive inner wall 1108 of the cylindrical ring structure 1112 are conductive cylinders arranged concentrically with each other, sandwiching the insulating structure 1114 therebetween, forming a cylindrical capacitor.

Capacitor 1146 is formed by housing inner wall 226d, insulating structure 1114, and conductive inner wall 1108 of cylindrical ring structure 1112. The housing inner wall 226d and the conductive inner wall 1108 of the cylindrical ring structure 1112 are conductive cylinders arranged concentrically with each other, sandwiching the insulating structure 1114 therebetween, forming a cylindrical capacitor.

Capacitor 1148 is formed from housing sidewall 226a, insulating structure 1114, and conductive outer wall 1106 of cylindrical ring structure 1112. The housing sidewall 226a and the conductive outer wall 1106 of the cylindrical ring structure 1112 are conductive cylinders arranged concentrically with respect to each other, sandwiching the insulating structure 1114 therebetween, forming a cylindrical capacitor.

The first node of capacitor 1142 and the first node of capacitor 1144 may be coupled to RF source 102 via conductive wall 1104 of cylindrical structure 1102. The first node of capacitor 1146, the first node of capacitor 1148, and the second node of capacitor 1142 are coupled to the common RF ground 262 via the housing inner wall 226 d.

The inductor 250 is formed by the radiating structure 222. The first node of inductor 250 is coupled to the second node of capacitor 1144 and the second node of capacitor 1146 via conductive inner wall 1108 of cylindrical ring structure 1112. A second node of inductor 250 is coupled to a second node of capacitor 1148 via conductive outer wall 1106 of cylindrical ring structure 1112.

Inductor 250, capacitor 1146, and capacitor 1148 form a resonant circuit 1152 (i.e., LC resonant circuit). With respect to FIG. 11A, housing inner wall 226d, insulating structure 1114, conductive inner wall 1108 of cylindrical ring structure 1112, conductive outer wall 1106 of cylindrical ring structure 1112, and housing side wall 226a form a resonant circuit 1152.

The various electrical and mechanical parameters of the structural components forming the inductors and capacitors of the resonant structure 1100 are selected such that the resonant structure 1100 operates at a desired operating frequency (i.e., resonates).

Fig. 11C illustrates a flow chart of an embodiment method 1160 that may be performed by the resonant structure 1100. At step 1162, the RF source 102 provides a forward RF wave to the conductive wall 1104 of the cylindrical structure 1102. In response, at step 1164, RF waves are transmitted from the conductive wall 1104 of the cylindrical structure 1102 to the radiating structure 222 (i.e., the inductor 250) through capacitive coupling between the capacitor 1142, the capacitor 1144, the capacitor 1146, and the capacitor 1148.

At step 1166, the radiating structure 222 radiates electromagnetic waves from the resonant structure 1100 into the plasma chamber 106. At step 1168, electromagnetic waves generate plasma 112. In such embodiments, the plasma generated by the RF discharge is classified as a purely inductively coupled plasma.

Fig. 12 shows a top view of an embodiment radiating structure 1200. In an embodiment, the radiating structure 1200 is also referred to as an antenna plate. The radiating structure 1200 has an inner radius 1202, an outer radius 1204, and a center point 1206.

In an embodiment, the inner radius 1202 of the radiating structure 1200 is substantially the same as, but slightly larger than, the outer radius of the annular structure 702. In such an embodiment, the center point 1206 of the radiating structure 1200 is the same as the center point of the annular structure 702.

In an embodiment, the inner radius 1202 of the radiating structure 1200 is substantially the same as, but slightly smaller than, the outer radius of the inner ring 210. In such an embodiment, the center point 1206 of the radiating structure 1200 is the same as the center point of the inner ring 210. Thus, the inner set of conductive offsets 224a may be placed vertically between the inner ring 210 and the radiating structure 1200.

In an embodiment, the outer radius 1204 of the radiating structure 1200 is substantially the same as the outer radius of the outer ring 212. In such an embodiment, the center point 1206 of the radiating structure 1200 is the same as the center point of the outer ring 212. Thus, the outer conductive offset set 224b may be placed vertically between the outer ring 212 and the radiating structure 1200.

In an embodiment, the radiating structure 1200 is a conductive planar closed loop structure having a plurality of spiral arms 1208. The spiral arms 1208 have n-fold symmetry about an axis passing through the center point 1206. In fig. 12, the number of spiral arms 1208 is shown as eight; however, the number of spiral arms 1208 is non-limiting and may be any number greater than one.

In an embodiment, the radiating structure 1200 is a unitary structure. In such an embodiment, the radiating structure 1200 includes a closed inner ring and a closed outer ring that provide mechanical connection to secure the spiral arms 1208 as a single unit.

In an embodiment, the individual spiral arms 1208 are formed using, for example, copper tubing that individually connects the inner set of conductive offsets 224a to the outer set of conductive offsets 224b. In an embodiment, the individual spiral arms 1208 are formed from individual workpieces, such as aluminum, that individually connect the inner conductive offset set 224a to the outer conductive offset set 224b. In such an embodiment, there is no inner or outer ring itself as in a unitary structure.

In an embodiment, the radiating structure 1200 is a conductive plate having a plurality of axisymmetric spiral cuts forming a plurality of spiral arms 1208. In embodiments where the radiating structure 1200 is formed from conductive plates, assembly and mechanical inconsistencies of the resonant structure are minimized, as production and manufacturing tolerances of the radiating structure 1200 are typically small. Advantageously, such a structure provides a more robust and repeatable electromagnetic wave. Furthermore, the design of the radiating structure 1200 provides a scaling function to accommodate multiple radial regions with respect to the generated electromagnetic field.

In an embodiment, the various capacitive structures allow for shorter antenna segments and axial symmetry.

In an embodiment, the radiating structure 1200 reduces unwanted dielectric etching and sputtering due to the high sheath electric field generated by the resonant structure when used in plasma processing. The resonant structure reduces dielectric etching and sputtering by transferring high electric fields to the internal and external capacitors of the resonant structure and placing high magnetic fields in close proximity to the plasma.

In an embodiment, the end points of each spiral arm 1208 are set at different measurement angles from the center point 1206 of the radiating structure 1200.

In an embodiment, the arrangement of spiral arms 1208 includes arranging the spiral arms in an arc between the ends of any combination of conductive offsets 224a-b or non-conductive offsets of any of the previously disclosed resonant structures.

In an embodiment, the arrangement of the spiral arms 1208 includes arranging the spiral arms 1208 in an arc between the ends of any pair of one of the inner conductive offset groups 224a and one of the outer conductive offset groups 224 b. In such an embodiment, the distal end of each corresponding pair is connected to any interface of any of the previously disclosed resonant structures.

In an embodiment, each spiral arm 1208 is additionally supported by one or more non-conductive offsets along the arc of the spiral arm 1208.

In an embodiment, the respective ends of each spiral arm 1208 have different radii measured from the center of each spiral arm 1208. In an embodiment, the respective ends of each spiral arm 1208 have different radial angles measured from the center of each spiral arm 1208. In an embodiment, the radial angle of each spiral arm is symmetrical.

In an embodiment, each spiral arm 1208 has a linear distance between its ends. In such embodiments, the linear distance of most of the spiral arms 1208 has the same or similar length.

In an embodiment, the arrangement of the spiral arms 1208 includes arranging the spiral arms 1208 such that the geometry of the spiral arms 1208 does not change during an angle of rotation of all spiral arms 1208 about the symmetry axis equal to 2 pi divided by an integer greater than 2. In an exemplary embodiment, the integer is equal to eight.

In an embodiment, the radiating structure 1200 is axisymmetric. In an embodiment, spiral arm 1208 has eight-fold symmetry.

As shown, the spiral arm 1208 has a design corresponding to an archimedes spiral forming a helical antenna. However, the design of the radiating structure 222 is non-limiting. For example, in an embodiment, the spiral arms 1208 may be logarithmic spiral shapes that form a spiral antenna. Further, the radiation structure 1200 is not limited to a helical antenna. For example, in an embodiment, the radiating structure 1200 may be a coil antenna or a disc antenna. As another example, the radiating structure 1200 may be a single coil arc, a double coil arc, or an integral arc.

The radiating structure 1200 is shown as a solid conductive plate with cutouts to form spiral arms 1208. However, it should be understood that in an embodiment, the radiating structure 1200 may include a plurality of wires arranged in a spiral configuration. In such an embodiment, one end of each wire is connected to the inner ring and the other end is connected to the outer ring. For example, referring to resonant structure 200, each of the inner set of conductive offsets 224a is connected to the inner ring and each of the outer set of conductive offsets 224b is connected to the outer ring.

In an embodiment, the radiating structures disclosed herein provide a uniform electromagnetic field within the plasma chamber 106. The uniform electromagnetic field makes the density distribution of the plasma 112 uniform, thereby making the substrate process inside it uniform.

In an embodiment, spiral arms 1208 are geometrically wrapped in a radial and azimuthal manner. In an embodiment, the spiral arms 1208 are positioned in a nested manner.

In an embodiment, each of the spiral arms 1208 has the same shape, length, and volume as the remaining spiral arms 1208.

Fig. 13A shows a side view of an embodiment resonating structure 1300. Resonant structure 1300 can operate as resonant structure 104 in plasma processing system 100 of fig. 1. Note that the resonant structure 1300 is not limited to applications in plasma processing, and other similar applications are also contemplated.

The resonant structure 1300 includes an inner radiating structure 1322a and an outer radiating structure 1322b. The inner radiating structure 1322a and the outer radiating structure 1322b are concentric conductive ring structures having the same center point. The outer radius of the inner radiating structure 1322a is smaller than the inner radius of the outer radiating structure 1322b.

In addition, the interface 1306 of the resonant structure 1300 includes a first inner ring 1302, a second inner ring 1308, a first outer ring 1310, and a second outer ring 1312 in place of the inner ring 210 and the outer ring 212 of the resonant structure 700. The first inner ring 1302, the second inner ring 1308, the first outer ring 1310, and the second outer ring 1312 are conductive ring structures that are substantially parallel to each other and to the back plate 208.

A first inner ring 1302 is disposed between the annular structure 702 and the RF source 102. A second inner ring 1308 is disposed between the first inner ring 1302 and the RF source 102. A first outer ring 1310 is disposed between the ring structure 702 and the RF source 102. The second outer ring 1312 is disposed between the first outer ring 1310 and the RF source 102.

The first inner ring 1302 and the first outer ring 1310 are shown as being substantially in the same plane and having the same center point. However, in an embodiment, the first inner ring 1302 and the first outer ring 1310 are in different planes. The outer radius of the first inner ring 1302 is smaller than the inner radius of the first outer ring 1310.

The second inner ring 1308 and the second outer ring 1312 are shown as being substantially in the same plane and having the same center point. However, in an embodiment, the second inner ring 1308 and the second outer ring 1312 are in different planes. The outer radius of the second inner ring 1308 is less than the inner radius of the second outer ring 1312.

In addition to conductive offsets 224a-b of resonant structure 700, resonant structure 1300 also includes conductive offsets 224c-d. As shown, the conductive offsets 224a-d are arranged perpendicular to the interface 1306, the inner radiating structure 1322a, and the outer radiating structure 1322 b. However, any of the conductive offsets 224a-d may also be arranged such that they connect the interface 1306 perpendicularly to the inner and outer radiating structures 1322a, 1322b, rather than perpendicularly to these surfaces.

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

As shown, the first inner conductive offset group 224a electrically couples the first inner ring 1302 to the interior of the inner radiating structure 1322 a. The second inner set of conductive offsets 224c electrically couples the second inner ring 1308 to the exterior of the inner radiating structure 1322 a. The first outer ring 1310 is electrically coupled to the interior of the outer radiating structure 1322b by a first outer set of conductive offsets 224 d. And, second outer conductive offset group 224b electrically couples second outer ring 1312 to the exterior of external radiating structure 1322 b.

In an embodiment, the ends of each of the first inner conductive offset groups 224a are disposed equidistant from each other along the surface of the first inner ring 1302. In an embodiment, the ends of each of the second inner conductive offset groups 224c are disposed equidistant from each other along the surface of the second inner ring 1308. In an embodiment, the ends of each of the first outer conductive offset groups 224d are disposed equidistant from each other along the surface of the first outer ring 1310. Also, in an embodiment, the ends of each of the second outer conductive offset groups 224b are disposed equidistant from each other along the surface of the second outer ring 1312.

In an embodiment, the non-conductive offset (not shown) may provide additional structural rigidity to the resonant structure 1300 by mechanically connecting the inner and outer radiating structures 1322a, 1322b to the interface 1306.

The insulating structure 1314 is composed of an electrically insulating material such as a dielectric material. The insulating structure 1314 is disposed between the first inner ring 1302 and the second inner ring 1308, between the first inner ring 1302 and the first outer ring 1310, between the first outer ring 1310 and the second outer ring 1312, between the second inner ring 1308 and the second outer ring 1312, and between each of the second inner ring 1308 and the second outer ring 1312 and the back plate 208.

Fig. 13B shows a schematic 1340 of the resonant structure 1300 of the embodiment of fig. 13A. Schematic 1340 includes RF source 102, inductor 722, inductor 1342, inductor 1344, inductor 1346, inductor 1348, capacitor 1350, capacitor 1352, capacitor 1351, and capacitor 1353, which may (or may not) be arranged as shown in fig. 13B.

Inductor 722 is formed from ring structure 702. A first node of the ring structure 702 is coupled to the RF source 102 and a second node of the ring structure 702 is coupled to a common RF ground of the resonant structure 1300.

The inductor 1342 is formed by the inner radial structure of the inner radiating structure 1322a (the portion of the inner radiating structure 1322a mechanically connected to the first inner set of conductive offsets 224 a). The inductor 1342 (i.e., the internal radiating structure 1322 a) is inductively coupled to the inductor 722 in response to the RF source 102 providing RF waves to the first end 712 of the ring structure 702.

The inductor 1346 is formed by the inner radial structure of the outer radiating structure 1322b (the portion of the outer radiating structure 1322b mechanically connected to the first outer set of conductive offsets 224 d). The inductor 1346 (i.e., the external radiating structure 1322 b) is inductively coupled to the inductor 722 in response to the RF source 102 providing RF power to the first end 712 of the ring structure 702.

Inductor 1344 is formed from internal radiating structure 1322 a. The internal radiating structure 1322a as a whole forms an inductor 1342 and an inductor 1344, which may be represented by a single inductor.

Inductor 1348 is formed from external radiating structure 1322 b. The external radiating structure 1322b as a whole forms an inductor 1346 and an inductor 1348, which may be represented by a single inductor.

The capacitor 1350 is formed by the first inner ring 1302, the insulating structure 1314, and the second inner ring 1308. The first inner ring 1302 and the second inner ring 1308 are concentric conductive plates arranged in parallel, sandwiching an insulating structure 1314 therebetween, forming a parallel plate capacitor.

The capacitor 1352 is formed of a first outer ring 1310, an insulating structure 1314, and a second outer ring 1312. The first outer ring 1310 and the second outer ring 1312 are concentric conductive plates arranged in parallel, sandwiching an insulating structure 1314 therebetween, forming a parallel plate capacitor.

The capacitor 1351 is formed by the second inner ring 1308, the insulating structure 1314, and the backplate 208. The second inner ring 1308 and the back plate 208 are concentric conductive plates arranged in parallel, sandwiching an insulating structure 1314 therebetween, forming a parallel plate capacitor. The back plate 208 is connected to a common RF ground of the resonant structure 1300. However, in embodiments, the back plate 208 may be left floating.

The capacitor 1353 is formed by the second outer ring 1312, the insulating structure 1314, and the backplate 208. As shown, the second outer ring 1312 and the back plate 208 are concentric conductive plates arranged in parallel, sandwiching an insulating structure 1314 therebetween, forming a parallel plate capacitor. As shown, the backplate 208 is connected to a common RF ground of the resonant structure 1300. However, in embodiments, the back plate 208 may be left floating.

The node of the inductor 1342 is coupled to the first node of the capacitor 1350 via the second inner conductive offset group 224c and the second inner loop 1308. The node of inductor 1346 is coupled to the first node of capacitor 1352 via second external conductive offset set 224b and second external loop 1312. The node of the inductor 1344 is coupled to the second node of the capacitor 1350 via the first inner conductive offset group 224a and the first inner loop 1302. The node of the inductor 1348 is coupled to the second node of the capacitor 1352 via the first external set of conductive offsets 224d and the first outer loop 1310.

The inductor 1342, the inductor 1344, and the capacitor 1350 form an internal resonant circuit 1354 (i.e., an LC resonant circuit). With respect to fig. 13A, the first inner ring 1302, the insulating structure 1314, the second inner ring 1308, the first inner set of conductive offsets 224a, the second inner set of conductive offsets 224c, the inner radiating structure 1322a, and the backplate 208 form an internal resonant circuit 1354.

The inductor 1346, the inductor 1348, and the capacitor 1352 form an external resonant circuit 1356 (i.e., an LC resonant circuit). With respect to fig. 13A, the first outer ring 1310, the insulating structure 1314, the second outer ring 1312, the first outer set of conductive offsets 224d, the second outer set of conductive offsets 224b, the outer radiating structure 1322b, and the backplate 208 form an external resonant circuit 1356.

The various electrical and mechanical parameters of the structural components forming the inductors and capacitors of the resonant structure 1300 are selected such that the resonant structure 1300 operates/resonates at a desired operating frequency.

In an embodiment, the inner resonant circuit 1354 operates at a first resonant frequency and the outer resonant circuit 1356 operates at a second resonant frequency. In an embodiment, the second resonant frequency is different from the first resonant frequency. In other embodiments, the first resonant frequency is the same as the second resonant frequency.

In embodiments where the second resonant frequency is different from the first resonant frequency, the first interior region of the plasma and the second exterior region of the plasma are generated by an internal resonant circuit 1354 and an external resonant circuit 1356, respectively, within the plasma chamber 106. The internal resonant circuit 1354 and the external resonant circuit 1356 can function as inductive pick-up of power, inductive coupling to the plasma, or both.

In an embodiment, the RF source 102 is configured to feed RF power to the internal resonant circuit 1354 and the external resonant circuit 1356. In such an embodiment, RF source 102 provides an RF wave that superimposes two co-propagating waves that differ in frequency, corresponding to the first and second resonant frequencies, respectively.

Fig. 13C illustrates a flow chart of an embodiment method 1360 that may be performed by the internal resonant circuit 1354 of the resonant structure 1300. At step 1362, the RF source 102 provides forward RF waves to the annular structure 702 via the first end 712. In response, at step 1364, RF waves are transmitted from the ring structure 702 to the internal radiating structure 1322a through inductive coupling between the inductor 722 and the inductor 1342.

At step 1366, the internal radiating structure 1322a radiates electromagnetic waves from the internal resonant circuit 1354 of the resonant structure 1300 into the plasma chamber 106. At step 1368, the electromagnetic wave generates a plasma 112. In such embodiments, the plasma generated by the RF discharge is classified as a purely inductively coupled plasma.

Fig. 13D illustrates a flow chart of an embodiment method 1380 that may be performed by the external resonant circuit 1356 of the resonant structure 1300. At step 1382, the RF source 102 provides forward RF waves to the annular structure 702 via the first end 712. In response, at step 1384, RF waves are transmitted from the ring structure 702 to the external radiating structure 1322b through inductive coupling between the inductor 722 and the inductor 1346.

At step 1386, the external radiating structure 1322b radiates electromagnetic waves from the external resonant circuit 1356 of the resonant structure 1300 to the plasma chamber 106. At step 1388, electromagnetic waves generate plasma 112. In such embodiments, the plasma generated by the RF discharge is classified as a purely inductively coupled plasma.

Fig. 14 shows a top view of an embodiment radiating structure 1400 having an inner radiating structure 1402 and an outer radiating structure 1404. In an embodiment, the inner radiating structure 1322a and the outer radiating structure 1322b of the resonant structure 1300 are represented by the inner radiating structure 1402 and the outer radiating structure 1404, respectively.

The inner radiating structure 1402 and the outer radiating structure 1404 are concentric conductive ring structures with spiral cuts. The inner radiating structure 1402 is located within an inner annular cutout of the outer radiating structure 1404 and is coplanar with and has the same center point as the outer radiating structure 1404. Each of the inner radiating structure 1402 and the outer radiating structure 1404 form a helical antenna.

Although the present specification has been described in detail, it should be understood that various changes, substitutions and alterations can be made hereto without departing from the spirit and scope of the disclosure as defined by the appended claims. In the different drawings, the same elements are denoted by the same reference numerals. Furthermore, the scope of the present disclosure is not intended to be limited to the particular embodiments of the present disclosure, as one of ordinary skill in the art will readily appreciate from the disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

Accordingly, the specification and drawings are to be regarded only as illustrative of the disclosure as defined by the appended claims, and are to be construed as covering any and all modifications, variations, combinations, or equivalents that fall within the scope of the disclosure. It should be understood that the physical arrangement and placement of components in various embodiments, such as a plasma processing system or a resonant structure, is not limiting. For example, while in each illustration the resonant structure is disposed between the RF source and the plasma processing system, such an arrangement is non-limiting and it is within the scope of the disclosure that these components may be disposed adjacent to, above, or below other components.

Claims

1. An apparatus for a plasma processing system, the apparatus comprising:

an interface, the interface comprising:

a first conductive plate capable of being coupled to an RF source,

a second conductive plate disposed between the RF source and the first conductive plate, an

A concentric conductive ring structure disposed between the second conductive plate and the substrate holder, a radiating structure; and

conductive offsets arranged to couple the concentric conductive ring structures to the radiating structure.

2. The apparatus of claim 1, wherein the second conductive plate is grounded.

3. The apparatus of claim 1, wherein the radiating structure comprises a third conductive plate having a plurality of axisymmetric spiral cuts.

4. The apparatus of claim 1, wherein the plasma processing system comprises a processing chamber having a substrate holder, wherein a substrate to be processed in the processing chamber is mounted on the substrate holder.

5. The apparatus of claim 4, wherein the apparatus is disposed outside of the process chamber.

6. The apparatus of claim 1, wherein the first conductive plate is coupled to the RF source via a coaxial conductive structure, and wherein the RF source feeds RF power to the first conductive plate via the coaxial conductive structure.

7. The apparatus of claim 1, further comprising non-conductive offsets through which the radiating structure is coupled to insulating structures disposed between conductive inner ring structures of the concentric conductive ring structures and conductive outer ring structures of the concentric conductive ring structures.

8. The apparatus of claim 1, wherein the interface, the radiating structure, and the conductive offsets form a resonant circuit in response to the RF source providing RF power to the first conductive plate.

9. An apparatus for a plasma processing system, the apparatus comprising:

an interface, the interface comprising:

a first conductive structure capable of being coupled to an RF source,

a second conductive structure disposed between the RF source and the first conductive structure, each concentric conductive structure being isolated from the second conductive structure by an air gap, and

a concentric conductive structure; and

a radiating structure coupled to the interface.

10. The apparatus of claim 9, wherein each concentric conductive structure is isolated from adjacent concentric conductive structures by the air gap.

11. The apparatus of claim 9, further comprising conductive offsets coupling the concentric conductive structures to the radiating structure.

12. The apparatus of claim 9, wherein the radiating structure has a resonant frequency between 5 and 100 megahertz (MHz).

13. The apparatus of claim 9, wherein the radiating structure comprises:

a conductive plate having a spiral cut; and

an inner circular cutout, wherein the first conductive structure is arranged substantially on the same plane as the radiating structure and is positioned within the inner circular cutout.

14. The apparatus of claim 9, wherein the plasma processing system comprises a processing chamber having a substrate holder, wherein a substrate to be processed in the processing chamber is mounted on the substrate holder.

15. An antenna system for exciting a plasma by inductive coupling, the antenna system comprising:

a plate;

a conductive ring structure arranged parallel to the plate, the plate and the conductive ring structure forming a first capacitor having a capacitance value substantially the same along one conductive ring structure;

conductive offsets, each conductive offset having a first end and a second end, the first end of each conductive offset being coupled to the conductive ring structure in a vertically disposed manner, each conductive offset being disposed equidistant from the other conductive offsets along the conductive ring structure; and

a plurality of spiral arms coupled to a corresponding second end of each conductive offset, each spiral arm arranged in a radial, azimuthal, and nested arrangement, each spiral arm having the same shape, length, and spacing, the plurality of spiral arms, conductive offset, and the conductive loop structures forming a resonant structure that resonates at an RF frequency.

16. The antenna system of claim 15, further comprising at least one drive conductive structure capacitively coupled to the resonant structure and capable of coupling to an RF source.

17. The antenna system of claim 15, further comprising a conductive coil structure inductively coupled to the resonant structure, the conductive coil structure and the resonant structure forming an inductively coupled pair, and the conductive coil structure being capable of coupling to an RF source.

18. The antenna system of claim 15, wherein the conductive ring structure comprises a conductive inner ring structure and a conductive outer ring structure adjacent to the conductive inner ring structure, each of the conductive inner ring structure and the conductive outer ring structure coupled to the plurality of spiral arms by the conductive offsets.

19. The antenna system of claim 15, wherein one of an inner edge or an outer edge of each of the plurality of spiral arms is connected to the conductive loop structure by the conductive offsets, and wherein the other edge of each of the plurality of spiral arms is not directly connected to a conductive structure or ground.

20. The antenna system of claim 15, wherein the plurality of spiral arms, the plate, and the conductive loop structure are arranged substantially parallel to one another.