Device for plasma processing

Abstract

The apparatus for plasma processing includes a first resonant structure and a second resonant structure. The first resonant structure is coupled to a first RF generator through a first matching circuit. The second resonant structure surrounds the second resonant structure. The second resonant structure is coupled to a second RF generator through a second matching circuit.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of U.S. Non - Provisional Application No. 17 / 748,737, filed May 19, 2022, the contents of which are incorporated herein by reference.

[0002] This disclosure generally relates to semiconductor processing technology and, in certain embodiments, to an apparatus for plasma processing.

Background Art

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

[0004] In a plasma processing system, electromagnetic waves radiated into a plasma chamber generate an electromagnetic field within the chamber. The generated electromagnetic field heats the electrons within the chamber. The heated electrons ignite the plasma to process a substrate in processes such as etching, deposition, oxidation, sputtering, etc.

Summary of the Invention

Problems to be Solved by the Invention

[0005] A non - uniform electromagnetic field within a plasma processing chamber results in non - uniform processing of a substrate because different portions of the substrate are processed by plasma with varying densities. Devices and systems that control the spatial distribution of the electromagnetic field and improve the uniformity of the plasma are desirable.

Means for Solving the Problems

[0006] According to one embodiment, an apparatus for plasma processing includes a first resonant structure coupled to a first RF generator through a first matching circuit, and a second resonant structure surrounding the first resonant structure and coupled to a second RF generator through a second matching circuit.

[0007] According to another embodiment, an apparatus for plasma processing includes a first resonant structure that forms a first zone for a first plasma affected by the first resonant structure, and a second resonant structure that forms a second zone for a second plasma affected by the second resonant structure, the second zone surrounding the first zone.

[0008] According to yet another embodiment, an apparatus for plasma processing includes a first cavity having a first resonant frequency and coupled to a conductive surface through a first capacitor, and a second cavity having a second resonant frequency, the second cavity being surrounded by the first cavity and coupled to the conductive surface through a second capacitor.

[0009] It should be understood that both the foregoing summary and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings.

[0011]

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Embodiments for Carrying Out the Invention

[0012] Corresponding numbers and symbols in different drawings generally refer to corresponding parts unless otherwise indicated. The drawings are drawn to clearly show relevant aspects of the embodiments and are not necessarily drawn to scale. The edges of the features depicted in the drawings do not necessarily indicate the end of the scope of those features.

[0013] Detailed Description of Exemplary Embodiments The creation and use of various embodiments are discussed in detail below. However, it should be recognized that the various embodiments described herein are applicable to a wide range of specific situations. The specific embodiments discussed are merely illustrative of specific ways of creating and using the various embodiments and should not be construed in a limited sense.

[0014] When referring to "an embodiment" or "one embodiment" in the context of this specification, it is intended to indicate that the particular configuration, structure, or feature described with respect to that embodiment is included in at least one embodiment. Thus, phrases such as "in one embodiment" or "in one embodiment" that may be present in one or more places in this specification do not necessarily refer to the same embodiment. Further, the particular forms, structures, or features can be combined in any suitable manner in one or more embodiments.

[0015] The references used herein are provided for convenience only and thus do not define the scope of protection or the scope of the embodiments. According to one or more embodiments of the present disclosure, the present application relates to a multi-zone resonance structure, each comprising two or more component resonance structures.

[0016] Aspects of the present invention are mainly described in the context of resonance structures in plasma processing systems, but aspects of the present invention can be similarly applied to fields other than the semiconductor industry. Plasma can be used for the treatment and modification of surface properties by functional group addition. For example, for treating a surface for paint deposition, plasma can convert a hydrophobic surface to a hydrophilic surface. Further, aspects of the present invention are not limited to plasma. For example, RF can be used for thawing frozen foods or drying textile products, foods, wood, etc. In these various examples, and across multiple industries, a uniform oscillating magnetic field as disclosed herein is advantageous.

[0017] In various embodiments, when referring to a magnetic field, it refers to a magnetic field oscillating at some frequency, for example, one of RF frequencies or microwave frequencies. In these embodiments, the magnetic field does not refer to a DC magnetic field. These details and other details will be discussed in more detail below.

[0018] According to embodiments, the multi-zone resonance structure provides control of the symmetry and radial uniformity of the generated plasma and is useful for plasma processing of substrates. The resonance structure can be a conductive structure having one or more resonant electromagnetic frequencies, and the resonance structure can be driven at one of or near one of its resonant electromagnetic frequencies. Each component resonance structure of the disclosed multi-zone resonance structure, also referred to as an individual resonance structure, can be operated at a single or multiple frequencies. Each component resonance structure can have a radiation structure (e.g., an antenna) or be coupled to a radiation structure to inductively couple or capacitively couple to the plasma in a nearby plasma chamber.

[0019] According to embodiments, the multi-zone resonance structure includes individual radial zones or resonance structures arranged concentrically. The multi-zone resonance structure can include two or more individual resonance structures. The individual resonance structures can have a cylindrical shape or a polygonal shape as seen in a top view. The individual resonance structures can be separated by shields. In other embodiments where the substrate to be processed by plasma is large and rectangular such that it can be used in the fabrication of flat panel displays, a number of individual resonance structures can be arranged adjacent to each other in a rectangular grid and controlled in a manner similar to the method described below.

[0020] According to embodiments, the multi-zone resonance structure includes tuning elements that tune the resonance frequencies of the individual resonance structures to which they are attached. The tuning elements can be components of a matching circuit that are coupled to components (e.g., inductors or capacitors) of the individual resonance structures and driven by external power.

[0021] According to an embodiment, the individual resonator structures of the multi-zone resonator structure can be controlled separately or together by excitation hardware, whereby each resonator structure can be driven at a power level independent of other resonator structures. The excitation hardware can include a capacitive structure or an inductive structure. The excitation hardware can be present in one individual resonator structure or in two or more resonator structures. The excitation hardware may be included in one individual resonator structure or may spread across two or more individual resonator structures.

[0022] According to an embodiment, the multi-zone resonator structure can include the mutual coupling between antennas, the controlled coupling between the influence zones of the generated plasma, and the controlled coupling between the electron donor and the generated plasma. The drive circuit of the influence zone can include a flexible matching circuit with harmonic sensing. The disclosed multi-zone resonator structure can be used with an inductively coupled resonant antenna, a capacitively coupled resonant antenna, or a hybrid resonant antenna of inductive coupling and capacitive coupling. The influence zones can be separated by shielding between the individual resonator structures. The shield can be grounded, floated, or physically integrated with the conductive components of the individual resonator structures.

[0023] According to one aspect, an apparatus for plasma processing includes a first resonator structure and a second resonator structure surrounding the first resonator structure, which may be referred to as a multi-zone resonator structure. The first resonator structure can be coupled to a first RF generator through a first matching circuit, and the second resonator structure can be coupled to a second RF generator through a second matching circuit. The first RF generator and the second RF generator can be the same RF generator.

[0024] In an embodiment, an RF power transfer mechanism for coupling RF power to a plasma is configured such that an RF generator is coupled to a matching circuit (e.g., through a first power transmission line). The matching circuit is coupled to a coupling structure, also referred to as a resonant structure (e.g., through a second power transmission line). The coupling structure is coupled to a resonant antenna. The resonant antenna is coupled to the plasma in a nearby plasma chamber.

[0025] FIG. 1 shows a diagram of a plasma processing system 100 according to an embodiment. The plasma processing system 100 includes an RF source 102, a multi-zone resonant structure 104, a plasma chamber 106, and optionally a dielectric plate 114, which may or may not be arranged as shown in FIG. 1. Further, the plasma processing system 100 may include additional components not depicted in FIG. 1.

[0026] In an embodiment, the RF source 102 includes an RF power supply, which may include a generator circuit and a matching circuit (not shown). The matching circuit may also be referred to as a matching network. The RF source 102 can supply a single frequency or multiple frequencies. In an embodiment, the matching circuit couples the RF source 102 to the multi-zone resonant structure 104 with one or more capacitors, inductors, or both. In an embodiment, the matching circuit is distributed on the multi-zone resonant structure 104. The impedance of the multi-zone resonant structure 104 may be different from the impedance of the power transmission line between the generator circuit and the multi-zone resonant structure 104. This impedance difference may lead to RF power reflection and a decrease in power efficiency. The matching circuit acts such that the impedance seen from the generator circuit side to the matching circuit is approximately equal to the internal impedance of the generator circuit. Thus, the matching circuit enhances the efficiency of power coupling from the RF source 102 to the multi-zone resonant structure 104.

[0027] In an embodiment, the RF source 102 is coupled to the multi-zone resonance structure 104 via a power supply structure 103. In an embodiment, the power supply structure 103 can include a power transmission line such as a coaxial cable, an interface with a conductive offset (see FIG. 2A described later), or a combination thereof. The RF source 102 supplies a forward RF wave to the multi-zone resonance structure 104. The multi-zone resonance structure 104 includes one or more resonance structures (see FIGS. 5A and 5B described later) and one or more radiation structures. In an embodiment, one or more radiation structures are enclosed in a grounded box, which blocks the electric field, reduces the magnetic field for human safety, and provides a ground return path from the plasma chamber 106 to the RF source 102. The forward RF wave travels through the multi-zone resonance structure 104 and is transmitted (i.e., radiated) toward the plasma chamber 106.

[0028] The plasma chamber 106 includes a substrate holder 108. As shown, a substrate 110 is disposed on the substrate holder 108 and is to be processed. 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 for removing by-products from the plasma chamber 106 by selective control of the internal gas flow rate. In an embodiment, the pump outlets 116 are disposed near (e.g., below / periphery of) the substrate holder 108 and the substrate 110.

[0029] In an embodiment, the multi-zone resonance structure 104 is separated from the plasma chamber 106 by a dielectric plate 114 made of a dielectric material. The dielectric plate 114 separates the low-pressure environment inside the plasma chamber 106 from the external atmosphere. It should be recognized that the multi-zone resonance structure 104 can also be disposed immediately adjacent to the plasma chamber 106, or the multi-zone resonance structure 104 can also be separated from the plasma chamber 106 by air. In an embodiment, the dielectric plate 114 is selected to minimize reflection of RF waves from the plasma chamber 106. In other embodiments, the multi-zone resonance structure 104 is at least partially embedded within the dielectric plate 114.

[0030] In one embodiment, the multi-zone resonance structure 104 couples RF power from the RF source 102 to the plasma chamber 106 to process the substrate 110. In particular, the multi-zone resonance structure 104 radiates one or more electromagnetic waves in response to the forward RF waves being fed from the RF source 102. The one or more radiated electromagnetic waves penetrate into the plasma chamber 106 from the atmosphere side of the dielectric plate 114 (i.e., the multi-zone resonance structure 104 side). The one or more radiated electromagnetic waves generate one or more respective electromagnetic fields within the plasma chamber 106. The generated one or more electromagnetic fields ignite and sustain the plasma 112 by transferring energy to the free electrons within the plasma chamber 106. The plasma 112 can be used, for example, to selectively etch or deposit a material on the substrate 110.

[0031] In FIG. 1, the multi-zone resonance structure 104 is shown to be outside the plasma chamber 106. However, in an embodiment, the multi-zone resonance structure 104 can be disposed inside the plasma chamber 106.

[0032] In an embodiment, one or more operating frequencies of the multi-zone resonance structure 104 are in the range of 1 MHz to 6 GHz. In an embodiment, the power delivered by the multi-zone resonance structure 104 is in the range of 10 W to 10 kW and is determined by various factors such as the distance from the multi-zone resonance structure 104, impedance value, etc.

[0033] Figures 2A - 4B show examples of resonance structures with various capacitor designs according to some embodiments. The resonance structure can be coupled to ground through one or more capacitive structures (e.g., fixed capacitor or variable capacitor). The resonance structures of Figures 2A - 4B are non-limiting examples showing possible configurations of a radiation structure, a capacitor, and a ground plane with no connection to power, and it should be recognized that all of these examples are capable of coupling to power (e.g., an RF source) to generate plasma.

[0034] Figure 2A shows a cross-sectional view of an example of a resonance structure (also called a cavity) having a radiation structure 210 (also called an antenna) coupled to a ground plane 202 (also called a conductive surface) through two conductive plates 205. Examples of the resonance structure can have any suitable shape, such as circular, polygonal, or ring-shaped in top view (see Figure 5B described later). In some embodiments, the radiation structure 210 is a spiral antenna. However, the radiation structure 210 can be any structure suitable for plasma generation. In some embodiments, the ground plane 202 is not grounded and is, for example, a common plate coupled to ground through a matching circuit.

[0035] The conductive plates 205 are each coupled to the radiation structure 210 by respective conductive offsets 208. Although the conductive offsets 208 are shown as being coupled to both ends of the radiation structure 210, the conductive offsets 208 can be coupled to any suitable location on the radiation structure 210. For example, one conductive offset 208 can be coupled to the outer edge of the radiation structure 210, and the other conductive offset 208 can be coupled to the center point of the radiation structure 210. The cross-section illustrated in FIG. 2A is a cut through the illustrated conductive offset 208. In embodiments, additional conductive offsets 208, or non-conductive (e.g., insulating) offsets, are present between the radiation structure 210 and the conductive plates 205.

[0036] The conductive plates 205 are further coupled to the ground plane 202 with the insulating structure 204 therebetween. The insulating structure 204 is composed of an electrical insulating material such as a dielectric material. In embodiments, the insulating structure 204 is composed of air or a vacuum.

[0037] FIG. 2B shows a circuit diagram of an example of the resonant structure of FIG. 2A, also referred to as a floating resonant structure. Each capacitor 206 is formed by a conductive plate 205 coupled to the ground plane 202 with the insulating structure 204 therebetween. The radiation structure 210 is coupled to the ground plane 202 through two capacitors 206 such that the capacitors 206 are between the radiation structure 210 and the ground plane 202 at both ends of the radiation structure 210. The two capacitors 206 represent the equivalent capacitance of a conductive structure including the respective conductive plates 205 and the ground plane 202. In some embodiments where the radiation structure 210 is an inductor, the radiation structure 210 and the capacitors 206 form a CLC circuit.

[0038] FIG. 3A shows a cross-sectional view of an example of a resonant structure, where one end of the radiation structure 210 is coupled to the ground plane 202 through a wide conductive plate 205a, and the other end is coupled to the ground plane 202 through the wide conductive plate 205a and a narrow conductive plate 205b.

[0039] The wide conductive plate 205a is separated from the ground plane 202 by the wide insulating structure 204a. The wide conductive plate 205a is coupled to the radiation structure 210 by the conductive offset 208. In some embodiments, the wide conductive plate 205a and the wide insulating structure 204a each have a width greater than or equal to the width of the radiation structure 210.

[0040] The narrow conductive plate 205b is separated from the wide conductive plate 205a by the narrow insulating structure 204b. The narrow conductive plate 205b is coupled to the radiation structure 210 by the conductive offset 208. In some embodiments, the narrow conductive plate 205b and the narrow insulating structure 204b each have a width less than the width of the radiation structure 210.

[0041] FIG. 3B shows a circuit diagram of an example of the resonant structure of FIG. 3A, in which one end of the radiation structure 210 is coupled to the ground plane 202 through the capacitor 206a, and the other end of the radiation structure 210 is coupled to the ground plane 202 through the capacitors 206a and 206b. The capacitor 206a is formed by the wide conductive plate 205a coupled to the ground plane 202 with the wide insulating structure 204a interposed therebetween. The capacitor 206b is formed by the narrow conductive plate 205b coupled to the wide conductive plate 205a with the narrow insulating structure 204b interposed therebetween. The examples of the resonant structures in FIGS. 3A and 3B include an LC resonant circuit corresponding to the inductance of the radiation structure 210 coupled to the capacitance of the capacitor 206b.

[0042] FIG. 4A shows a cross-sectional view of an example of the resonant structure, in which one end of the radiation structure 210 is grounded and the other end is coupled to the ground plane 202 through the conductive plate 205c. One end of the radiation structure 210 is coupled to the ground plane 202 through the conductive offset 208 (also referred to as a post).

[0043] The conductive plate 205c is separated from the ground plane 202 by the insulating structure 204c. The narrow conductive plate 205c is coupled to the radiation structure 210 by another conductive offset 208.

[0044] FIG. 4B shows a circuit diagram of an example of the resonance structure of FIG. 4A. In the figure, one end of the radiation structure 210 is grounded by connection to the ground plane 202, and the other end of the radiation structure 210 is coupled to the ground plane 202 through the capacitor 206c. The capacitor 206c is formed by a conductive plate 205c coupled to the ground plane 202 with the insulating structure 204c interposed therebetween. In some embodiments where the radiation structure 210 is an inductor, the radiation structure 210 and the capacitor 206c form an LC circuit.

[0045] FIGS. 5A and 5B show a multi-zone resonance structure 500 according to some embodiments, in which an outer resonance structure 502 surrounds an inner resonance structure 504. FIG. 5A shows a cross-sectional view of the multi-zone resonance structure 500, and FIG. 5B shows a top view of the multi-zone resonance structure 500. As shown in FIGS. 5A and 5B, the outer resonance structure 502 and the inner resonance structure 504 have a cylindrical shape centered on the axis 510. The outer resonance structure 502 and the inner resonance structure 504 are also referred to as radial zones or cavities. Although FIGS. 5A and 5B are shown with a cylindrical resonance structure, it should be recognized that the shape of the resonance structure (here, the cylindrical shape) is non-limiting, and other shapes are equally conceivable (see FIG. 5C described later).

[0046] The outer resonance structure 502 and the inner resonance structure 504 can each include their respective radiation structures 210, capacitors, and conductive offsets, as shown in FIGS. 2A to 4B described above. For example, the outer resonance structure 502 and the inner resonance structure 504 can each have their respective radiation structures 210 on their respective bottom sides. However, any suitable internal structure can be used for the outer resonance structure 502 and the inner resonance structure 504.

[0047] When using a single fixed resonance frequency, the amount of power coupled to a particular resonance structure (e.g., outer resonance structure 502 or inner resonance structure 504) may be determined by the resonance frequency of the resonance structure relative to the fixed drive frequency of the power source (e.g., RF source 102, see FIG. 1 above) coupled to that resonance structure. The amount of plasma generated by the resonance structure can be advantageously adjusted to a desired amount by tuning the resonance frequency of the resonance structure, such as by using tuning element 506.

[0048] In some embodiments, each tuning element 506 is coupled to outer resonance structure 502 and inner resonance structure 504. Tuning element 506 can be part of a matching circuit driven by external power and coupled to components (e.g., inductors or capacitors) of outer resonance structure 502 and inner resonance structure 504. Tuning element 506 tunes the resonance frequency of the resonance structure to which it is attached. Tuning element 506 can be a mechanical or electrical tuning element and can include a plurality of distributed elements that can be individually switched on and off, such as capacitors, inductors, or combinations thereof, to change the resonance frequency of the resonance structure. Tuning element 506 can also be a single variable component, or an element such as a single variable capacitor (also called a varactor) or a single variable inductor. In some embodiments, tuning element 506 includes one or more elements having a fixed capacitance or fixed inductance and one or more elements having a variable capacitance or variable inductance.

[0049] To enhance the symmetry of the plasma generated by outer resonance structure 502 and inner resonance structure 504, it may be beneficial to arrange tuning element 506 in a symmetric pattern around axis 510. However, it should be recognized that tuning element 506 may be arranged in any suitable pattern, including an asymmetric arrangement.

[0050] The tuning element 506 forms a resonance structure and respective resonance circuits having plasma generated in the nearby plasma chamber 106 (see FIG. 1 above). For example, the outer resonance structure 502, the tuning element 506 coupled to the outer resonance structure 502, and the plasma coupled to the outer resonance structure 502 form a resonance circuit, and the inner resonance structure 504, the tuning element 506 coupled to the inner resonance structure 504, and the plasma coupled to the inner resonance structure 504 form a resonance circuit. The tuning element 506 enables the resonance frequencies of the respective resonance circuits including the outer resonance structure 502 and the inner resonance structure 504 to be tuned. In some embodiments, the tuning element 506 enables the resonance frequency of a resonance circuit without the tuning element 506 to be tuned over a range from 0.01 MHz to 100 MHz from the resonance frequency of the resonance circuit.

[0051] The tuning element 506 can be controlled to match changes in the load from a power source (e.g., RF source 102, see FIG. 1 above). The tuning by the tuning element 506 can be applied to the outer resonance structure 502 and the inner resonance structure 504 regardless of the presence or absence of tuning having a direct excitation effect on the plasma in the plasma chamber 106 (see FIG. 1 above) near the outer resonance structure 502 and the inner resonance structure 504. In addition to the tuning by the tuning element 506, one side of the radiation structure 210 of the resonance structure can be grounded (see FIG. 4A above).

[0052] In some embodiments, the tuning element 506 is not present in the multi-zone resonance structure 500. When the tuning element 506 is not present, the outer resonance structure 502 and the inner resonance structure 504 can have respective fixed resonance frequencies.

[0053] In some embodiments, the radiation structures 210 of the outer resonance structure 502 and the inner resonance structure 504 are inductors and have a mutual inductive coupling therebetween.

[0054] FIG. 5C shows a top view of an embodiment of the multi-zone resonance structure 500. In the figure, the outer resonance structure 502, the inner resonance structure 504, and the tuning element 506 have polygonal inner and outer side walls. As shown in FIG. 5C, the multi-zone resonance structure 500 has an octagonal shape in top view. However, the multi-zone resonance structure 500 can have any suitable shape, such as a square shape, a pentagonal shape, a hexagonal shape, a dodecagonal shape, etc., and any suitable combination of straight and curved side walls is understood to be within the scope of the embodiment.

[0055] FIG. 5D shows an example of a circuit diagram of the multi-zone resonance structure 500 of FIG. 5A. In the figure, the outer resonance structure 502 and the inner resonance structure 504 share a capacitor. The radiation structure 210 of the outer resonance structure 502 is coupled to ground with capacitors 516A and 516B interposed therebetween, and the radiation structure 210 of the inner resonance structure 504 is coupled to ground with capacitors 516B and 516C interposed therebetween. Thus, the capacitor 516B is shared by the outer resonance structure 502 and the inner resonance structure 504, such as by sharing one or more conductive offsets 208 (see FIG. 2A above) at the boundary between the outer resonance structure 502 and the inner resonance structure 504.

[0056] In some embodiments, the outer resonance structure 502 and the inner resonance structure 504 of FIG. 5D share the capacitor 5126B, but they operate at different frequencies supplied as two sets of pulses having different frequencies or as multi-tone mixing of two or more frequencies.

[0057] FIG. 5E and FIG. 5F respectively show a cross-sectional view and a top view of an embodiment of the multi-zone resonance structure 500. As shown, an additional resonance structure 508 surrounds the outer resonance structure 502 and the inner resonance structure 504. As shown in FIG. 5E, the multi-zone resonance structure 500 has three individual resonance structures around the axis 510. However, the multi-zone resonance structure 500 can include any suitable number of resonance structures, such as four to six resonance structures arranged around the axis 510. In the case of an example of a plasma reactor or chamber having resonance structures arranged in a grid (e.g., designed for the manufacture of flat panel displays), the number of resonance structures may be greater than six, such as 16 to 32 resonance structures. In addition, each tuning element 506 may be present on the outer resonance structure 502, on the inner resonance structure 504, on the additional resonance structure 508, or any combination thereof.

[0058] As shown in FIG. 5F, the outer resonance structure 502, the inner resonance structure 504, and the additional resonance structure 508 have a circular shape in top view. However, the outer resonance structure 502, the inner resonance structure 504, the additional resonance structure 508, and any other resonance structures arranged around the axis 510 can have any suitable circular or polygonal shape with any combination of straight or circular sidewalls.

[0059] FIG. 5G shows an example of a circuit diagram of the multi-zone resonance structure 500 of FIGS. 5E and 5F. In the figure, the outer resonance structure 502 and the inner resonance structure 504 share a capacitor, and the outer resonance structure 502 and the additional resonance structure 508 share a capacitor. The radiation structure 210 of the outer resonance structure 502 is coupled to ground with capacitors 516A and 516B interposed therebetween, the radiation structure 210 of the inner resonance structure 504 is coupled to ground with capacitors 516B and 516C interposed therebetween, and the radiation structure 210 of the additional resonance structure 508 is coupled to ground with capacitors 516A and 516D interposed therebetween. Thus, capacitor 516A is shared by the outer resonance structure 502 and the additional resonance structure 508, and capacitor 516B is shared by the outer resonance structure 502 and the inner resonance structure 504.

[0060] FIGS. 6 to 12 show various embodiments of a multi-zone resonance structure having excitation hardware. The multi-zone resonance structures of FIGS. 6 to 12 can have the same structure as the multi-zone resonance structure 500 described above with respect to FIGS. 5A and 5B, where like elements are denoted by like numerals. For example, the multi-zone resonance structure can have a cylindrical shape and is shown along the same cross-sectional view as shown in FIG. 5A.

[0061] FIG. 6 shows an example of a multi-zone resonance structure 600 having excitation hardware according to some embodiments. The excitation component 602 physically exists in the inner resonance structure 504 of the multi-zone resonance structure 600. The excitation component 602 can be a suitable hardware component capable of affecting or exciting an electric field or a magnetic field in the resonance structure of the multi-zone resonance structure 600, such as an induction coil that generates a magnetic field or a capacitor that generates an electric field. In some embodiments, the excitation component 602 affects or excites the plasma 112 (see FIG. 1 above) in the plasma chamber 106. The excitation component 602 is driven by a power source or an external generator (e.g., RF source 102, see FIG. 1 above) that can be coupled to the excitation component through a matching circuit.

[0062] As shown in FIG. 6, the influence zone 604 of the excitation component 602 extends across the entire inner resonance structure 504 and the entire outer resonance structure 502. As an example, when the excitation component 602 is an induction coil, the influence zone 604 can be a magnetic field generated by the excitation component 602. In some embodiments, the influence zone 604 includes a magnetic field coupled from the radiation structure to the plasma 112 with an intensity in the range of 0.1 G to 2 T, or an electric field coupled with an intensity in the range of 1 V / cm to 3000 V / cm. An electric field can be induced in the plasma 112 with an intensity in the range of 10 V / cm to 300 V / cm, or a current in the range of 1 A to 20 A can be induced in the plasma. The excitation component 602 can excite an electric field or a magnetic field within the inner resonance structure 504 and the outer resonance structure 502, and it is desirable that the electric field or magnetic field can then advantageously increase the energy or density of the plasma 112 by exciting the plasma 112. This can be useful for plasma processing of the substrate.

[0063] To enhance the symmetry of the plasma generated by the outer resonance structure 502 and the inner resonance structure 504, it may be beneficial to arrange the excitation hardware (including the excitation component 602) in a symmetric pattern around the axis 510. However, it should be recognized that the excitation hardware may be arranged in any suitable pattern including an asymmetric arrangement.

[0064] FIG. 7 shows an example of a multi-zone resonance structure 700 with excitation hardware according to some embodiments. The excitation component 702 physically exists in the outer resonance structure 502 of the multi-zone resonance structure 700. The excitation component 702 can be an appropriate hardware component similar to the excitation component 602 described above with respect to FIG. 6. As shown in FIG. 7, the influence zone 704 of the excitation component 702 extends across the entire inner resonance structure 504 and the entire outer resonance structure 502. As shown in FIGS. 6 and 7, the excitation hardware exists in either the inner resonance structure 504 or the outer resonance structure 502 and can generate an influence zone across both the inner resonance structure 504 and the outer resonance structure 502.

[0065] FIG. 8 shows an example of a multi-zone resonance structure 800 with excitation hardware according to some embodiments. In FIG. 8, an excitation component 802a physically exists in the outer resonance structure 502 of the multi-zone resonance structure 800, and another excitation component 802b physically exists in the inner resonance structure 504 of the multi-zone resonance structure 800. The excitation component 802a of the outer resonance structure 502 generates an influence zone 804a within the outer resonance structure 502, and the excitation component 802b of the inner resonance structure 504 generates an influence zone 804b within the inner resonance structure 504.

[0066] FIG. 9 shows an example of a multi-zone resonance structure 900 with excitation hardware and a shield that separates the outer resonance structure 502 from the inner resonance structure 504. The multi-zone resonance structure 900 can be the same as the multi-zone resonance structure 800 described above with respect to FIG. 8, with a shield 902 added.

[0067] The shield 902 separates the outer resonance structure 502 from the inner resonance structure 504. Due to the shield, the respective influence zones 804a and 804b of each excitation component 802a and 802b can be confined to the respective resonance structures containing the excitation component 802a or 802b.

[0068] As an example, the shield 902 can be a cylindrical sheet made of a conductive material such as copper. In some embodiments, the shield 902 has a thickness in the range of 0.1 mm to 12.7 mm. The shield 902 can prevent the penetration of the electric field from capacitive coupling and reduce the penetration of the magnetic field from inductive coupling. In some embodiments, the shield 902 is a metal such as aluminum. The shield 902 can be coupled to ground or can be floated. In some embodiments, the shield 902 has an inner liner or an outer liner made of an absorptive material that absorbs or blocks a magnetic field or an electric field, such as a high-permeability ferrite (cobalt nickel zinc) material for frequencies in the range of 2 MHz to 150 MHz. In some embodiments, the shield 902 is physically coupled to the insulating structure 204 (see FIG. 2A above). For example, the shield 902 can be supported by a dielectric support coupled to the insulating structure 204. The shielding can be part of an integrated support that couples the radiation structure 210 to the capacitor 206, such as the laminated conductive offset 208 (see FIGS. 2A and 2B above). For example, the conductive offset 208 containing aluminum can be laminated with a tin-based material.

[0069] FIG. 10 shows an example of a multi-zone resonance structure 1000 having excitation hardware that spreads into and affects a plurality of resonance structures according to some embodiments. The excitation component 1002 spreads into both the inner resonance structure 504 and the outer resonance structure 502. The influence zone 1004 generated by the excitation component 1002 spreads across both the inner resonance structure 504 and the outer resonance structure 502.

[0070] Figures 11 and 12 respectively show examples of multi-zone resonance structures 1100 and 1200 in which an electric field or a magnetic field within an influence zone is coupled to an adjacent resonance structure. An electric field or a magnetic field within an influence zone that has a local influence within one resonance structure can be coupled to an electric field or a magnetic field within the other resonance structure and can excite the electric field or the magnetic field of the other resonance structure. This may occur when the difference between the resonance frequencies of the outer resonance structure 502 and the inner resonance structure 504 is 100 MHz or less, for example, when there is a difference in the range of 1 kHz to 2000 kHz. Unwanted coupling between adjacent resonance structures can be reduced or prevented by supplying RF power in pulses or by shielding the resonance structures from each other.

[0071] In FIG. 11, an excitation component 1102 is present in the outer resonance structure 502, generating an influence zone 1104 that locally affects the electric field or the magnetic field within the outer resonance structure 502. However, the outer resonance structure 502 is capacitively or inductively coupled to the inner resonance structure 504. As indicated by the arrows, when the outer resonance structure 502 is excited, the electric field or the magnetic field within the outer resonance structure 502 is further coupled to the electric field or the magnetic field within the inner resonance structure 504 by capacitive or inductive coupling.

[0072] In FIG. 12, an excitation component 1202 is present in the inner resonance structure 504, generating an influence zone 1204 that locally affects the electric field or the magnetic field within the inner resonance structure 504. However, the inner resonance structure 504 is capacitively or inductively coupled to the outer resonance structure 502. As indicated by the arrows, when the inner resonance structure 504 is excited, the electric field or the magnetic field within the inner resonance structure 504 is further coupled to the electric field or the magnetic field within the outer resonance structure 502 by capacitive or inductive coupling.

[0073] Referring further to FIGS. 11 and 12, a plasma (e.g., the plasma in the nearby plasma chamber 106, see FIG. 1) coupled to an electric or magnetic field from the influence zone of one resonance structure (e.g., the outer resonance structure 502) and excited by the electric or magnetic field can capacitively or inductively couple to the plasma coupled to an adjacent resonance structure (e.g., the inner resonance structure 504). In some embodiments, this capacitive or inductive coupling of the plasmas coupled to adjacent resonance structures (e.g., the outer resonance structure 502 and the inner resonance structure 504) occurs when the plasma has a density in the range of 10 9 cm -3 ~10 12 cm -3 and the range of ion energy is 0.5 eV to 15 eV and the range of magnetic flux density is 0.1 G to 100 G.

[0074] In some embodiments, an inductive coupling occurs between the dielectric material near one resonance structure (e.g., the dielectric material in the dielectric plate 114, see FIG. 1 above) and the dielectric material near an adjacent resonance structure. The dielectric material can support a vacuum in the plasma chamber 106 and have a thickness in the range of 20 mm to 25 mm.

[0075] FIGS. 13 to 16 show partial cross-sections of an example of a multi-zone resonance structure in which the cross-section penetrates each resonance structure once. For example, in the case of a multi-zone resonance structure having a cylindrical shape, FIGS. 13 to 16 show the respective partial cross-sections from the left side of each outer resonance structure 502 of each multi-zone resonance structure to each central axis 510 (not shown, see FIG. 5A above).

[0076] FIG. 13 shows an example of a multi-zone resonance structure 1300 having excitation hardware and variable coupling elements according to some embodiments. Each excitation component 802 is present in the outer resonance structure 502 and the inner resonance structure 504, each generating an influence zone 804. The excitation components 802 are coupled to a power distribution common element 1302 (also called a bus) by respective variable coupling elements 1306. The power distribution common element 1302 can be coupled to an RF generator (e.g., RF source 102, see FIG. 1 above).

[0077] The variable coupling element 1306 can be inductive or capacitive. The power and frequency supplied to the excitation component 802 can be controlled by changing the inductance or capacitance of the variable coupling element 1306. This makes it possible to supply different amounts of power or different frequencies to the excitation component 802 through a single power distribution common element 1302. It is possible to supply either one frequency or two frequencies to the excitation component 802. In embodiments where there are additional resonance structures having respective excitation components 802 and variable coupling elements 1306, it is possible to supply three or more frequencies to the excitation component 802.

[0078] FIGS. 14 to 16 show different excitation methods for a single excitation hardware configuration according to some embodiments. The excitation methods of FIGS. 14 to 16 enable control of a single resonance structure by one or more frequencies through the excitation component.

[0079] In FIG. 14, the multi-zone resonance structure 1400 includes an excitation component 702 within the outer resonance structure 502 and a tuning element 506 coupled to the inner resonance structure 504. The excitation component 702 generates an influence zone 704 on both the outer resonance structure 502 and the inner resonance structure 504. The first frequency F1 is supplied through the excitation component 702, and the tuning element 506 can control the resonance frequency of the inner resonance structure 504 independently of the resonance frequency of the outer resonance structure 502. Thereby, through the operation of the tuning element 506, it becomes possible to bring the resonance frequency of the inner resonance structure 504 closer to or farther from the first frequency F1.

[0080] It should be recognized that, as a non-limiting example, the excitation component 702 is in the outer resonance structure 502 and the tuning element 506 is coupled to the inner resonance structure 504. Any combination of the excitation component and the tuning element with their respective resonance structures is within the scope of the embodiments shown in FIGS. 14 to 16. For example, any resonance structure can have its respective excitation component and can be coupled to its respective tuning element.

[0081] In FIG. 15, the multi-zone resonance structure 1500 includes the excitation component 702 in the outer resonance structure 502, and the first frequency F1 and the second frequency F2 are simultaneously supplied to the excitation component 702. Thus, the excitation component 702 generates an influence zone 704 on both the outer resonance structure 502 and the inner resonance structure 504, which is controlled by the first frequency F1 and the second frequency F2.

[0082] In some embodiments, the first frequency F1 is close to the resonance frequency of the outer resonance structure 502 and strongly affects the outer resonance structure 502, and the second frequency F2 is close to the resonance frequency of the inner resonance structure 504 and strongly affects the inner resonance structure 504. The amount of power supplied to each of the outer resonance structure 502 and the inner resonance structure 504 can be controlled, for example, by controlling the amplitude of the waveforms having the first frequency F1 and the second frequency F2.

[0083] In FIG. 16, the multi-zone resonance structure 1600 includes an excitation component 702 in the outer resonance structure 502, and a third frequency F3 and a fourth frequency F4 are supplied to the excitation component 702 as an interleaved pulse. Thus, the excitation component 702 generates an influence zone 704 on both the outer resonance structure 502 and the inner resonance structure 504, which is controlled by the interleaved pulse consisting of the third frequency F3 and the fourth frequency F4.

[0084] In some embodiments, the third frequency F3 is close to the resonance frequency of the outer resonance structure 502 and strongly affects the outer resonance structure 502, and the fourth frequency F4 is close to the resonance frequency of the inner resonance structure 504 and strongly affects the inner resonance structure 504. The amount of power supplied to each of the outer resonance structure 502 and the inner resonance structure 504 can be controlled, for example, by controlling the length and amplitude of the interleaved pulse.

[0085] FIGS. 17 to 28 show various examples of the embodiments described above with respect to FIGS. 2A to 16. The examples shown in FIGS. 17 to 28 include a low-impedance coupling with capacitors of various configurations and a mutual inductive coupling in which a radiation structure (e.g., an antenna) is arranged close enough to enable a strong mutual coupling. It should be recognized that the examples in FIGS. 17 to 28 are non-limiting, and embodiments including any suitable combination of features from the examples in FIGS. 17 to 28 are within the scope of the present disclosure.

[0086] FIG. 17 shows a cross-sectional view of a multi-zone resonance structure 1700, which is a detailed example of the multi-zone resonance structure 500 described above with respect to FIG. 5A, but does not include a tuning element. The multi-zone resonance structure 1700 is shown without an excitation component (also called an excitation component) such as an inductive drive coil or a capacitor or a tuning element. However, the multi-zone resonance structure 1700 is a non-limiting example, and it should be recognized that embodiments may include any suitable combination of excitation components, tuning elements, feeding elements, or matching circuits, as described above or hereinafter.

[0087] In FIG. 17, the multi-zone resonance structure 1700 is shown to be disposed in the air 1720 above the dielectric plate 114 covering the plasma chamber 106. The dielectric plate 114 and the plasma chamber 106 can have the same structure as described above with respect to FIG. 1. The plasma chamber 106 contains the plasma 112 in an environment close to a vacuum. The plasma 112 is inductively coupled to the respective radiation structures 210 of the outer resonance structure 502 and the inner resonance structure 504.

[0088] Each of the outer resonance structure 502 and the inner resonance structure 504 includes a respective capacitor 206 formed by coupling a conductive plate 205 to a ground plane 202 with an insulating structure 204 interposed therebetween. The ground plane 202 is shown to be grounded, but the ground plane 202 may be floating or coupled to any appropriate reference voltage. Each capacitor 206 may be grounded, floating, or coupled to any appropriate reference voltage. For example, in an embodiment where one capacitor 206 is grounded and another capacitor 206 is floating, the ground plane 202 may have a gap or dielectric structure that electrically insulates the grounded capacitor 206 from the floating capacitor 206.

[0089] In the embodiment shown in FIG. 17, the outer resonance structure 502 has an outer capacitor 206A and an inner capacitor 206B, and the inner resonance structure 504 has an outer capacitor 206C and an inner capacitor 206D. In other embodiments, the outer resonance structure 502 and the inner resonance structure 504 may have different numbers or configurations of capacitors. For example, the outer resonance structure 502 and the inner resonance structure 504 can have shared capacitors and shared conductive offsets (see FIG. 20 described below) at their boundaries.

[0090] In some embodiments, a ground housing (not shown) extends from the ground plane 202 and encloses the plasma chamber 106, the outer resonant structure 502, and the inner resonant structure 504. The ground housing provides a ground return path for the power coupled into the plasma 112.

[0091] In some embodiments, the outer resonant structure 502 and the inner resonant structure 504 of the multi-zone resonant structure 1700 are each a floating resonant circuit zone including a respective outer capacitor 206, a respective radiation structure 210, and a respective inner capacitor 206. Any combination of the capacitors 206 can be grounded. The radiation structure 210 is inductively coupled to the plasma 112 in the plasma chamber 106.

[0092] In some embodiments, each radiation structure 210 includes eight arms having an Archimedean spiral shape provided between a respective inner ring and a respective outer ring. Each arm of each radiation structure 210 can be coupled to a common capacitor 206 through the respective inner and outer rings. In other embodiments, the arms are electrically insulated from each other by slits or dielectric materials.

[0093] FIG. 18 shows a cross-sectional view of a multi-zone resonant structure 1800, which is similar to the multi-zone resonant structure 1700 (see FIG. 17 above), but includes a stacked capacitor design. The outer resonant structure 502 and the inner resonant structure 504 each include a respective conductive plate 1805 overlapping a respective conductive plate 205. A respective insulating structure 1804 is provided between the conductive plate 1805 and the conductive plate 205. The capacitor 206 is formed by the coupling of the conductive plate 205 and the ground plane 202 with the insulating structure 204 interposed therebetween, and the capacitor 1806 is formed by the coupling of the conductive plate 1805 and the conductive plate 205 with the insulating structure 1804 interposed therebetween.

[0094] As shown in FIG. 18, capacitor 206 and capacitor 1806 are stacked within outer resonance structure 502 and inner resonance structure 504. This provides a more compact design, reducing the respective radii of outer resonance structure 502 and inner resonance structure 504 and potentially allowing one or more additional resonance structures to be included in the same amount of space around outer resonance structure 502.

[0095] Multi-zone resonance structure 1800 is shown without including a connection to a power drive (e.g., an induction drive coil or capacitor) or a tuning element. However, it should be recognized that multi-zone resonance structure 1800 is a non-limiting example and that embodiments may include any suitable combination of excitation components, tuning elements, feeders, or matching circuits, as described above or below.

[0096] FIG. 19 shows a cross-sectional view of multi-zone resonance structure 1900, which is a detailed example of inductive power coupling in one embodiment of multi-zone resonance structure 800 described above with respect to FIG. 8. Multi-zone resonance structure 1900 is similar to multi-zone resonance structure 1700 described above with respect to FIG. 17, but further includes induction drive coil 1910 acting as an excitation component that inductively couples to respective radiation structures 210 of outer resonance structure 502 and inner resonance structure 504 in outer resonance structure 502 and inner resonance structure 504, respectively. Induction drive coil 1910 can be isolated from plasma generation by being separated by a distance in the range of 5 mm to 100 mm from the wall of the grounded chamber or the shield of plasma chamber 106 (see FIG. 1 above).

[0097] Each induction drive coil 1910 is coupled to a respective power supply 1912 and a respective ground or matching circuit 1914. Each induction drive coil 1910 can receive a single or variable frequency through its respective power supply 1912. The ground or matching circuit 1914 can be coupled to either a ground or a matching circuit. In some embodiments, the power supply 1912 includes a plurality of power supplies for separately controlling power and frequency.

[0098] To transfer power to the plasma 112 through the radiation structure 210, the induction drive coils 1910 of the outer resonant structure 502 and the inner resonant structure 504 have an inductive coupling with the respective radiation structures 210 of the outer resonant structure 502 and the inner resonant structure 504. The induction drive coils 1910 may be designed to be resonant or non-resonant. Through the same induction drive coils 1910 and power supplies 1912, power can be transferred at two different frequencies. The radiation structure 210 can function as both an inductive pickup for power and an inductive antenna for coupling to the plasma 112.

[0099] In some embodiments, the induction drive coils 1910 are present in each of the outer resonant structure 502 and the inner resonant structure 504 as single-turn coils. The induction drive coils 1910 are independent of each other and each can have a single-turn design or a multi-turn design. However, the induction drive coils 1910 can be of any shape that couples to the respective radiation structures 210. For example, the induction drive components may be arcs or line segments that match the pattern of the respective radiation structures 210 rather than coils. In some embodiments, the induction drive coils 1910 are each a pair of half coils that cover 180° of each of the azimuthal planes, and each half coil has its own coupling to a respective power supply and a ground or matching circuit.

[0100] FIG. 20 shows a cross-sectional view of the multi-zone resonance structure 2000, which is a detailed example of inductive power coupling in one embodiment of the multi-zone resonance structure 600 described above with respect to FIG. 6. The multi-zone resonance structure 2000 includes a radiation structure 210 and an inductive drive coil 2010 coupled to a ground plane 202 by a low-impedance common center capacitor 206. In some embodiments, the capacitance of the common center capacitor 206 ranges from 5 pF to 1000 pF. The outer resonance structure 502 and the inner resonance structure 504 can operate at different resonance frequencies even though they share the common center capacitor 206. The ground plane 202 includes a central hole around the axis 510, through which a power supply 2012 and a ground or matching circuit 2014 are coupled to the inductive drive coil 2010.

[0101] The inductive drive coil 2010 can receive two frequencies through a single power supply 2012 and act as an excitation component to inductively couple with the magnetic field generated by the radiation structure 210. The inductive drive coil 2010 also inductively couples with the plasma 112 to generate the plasma.

[0102] The outer resonance structure 502 has a low-impedance outer capacitor 206 and a low-impedance inner capacitor 206 shared with the inner resonance structure 504. Thus, the outer capacitor 206, the radiation structure 210, and the inner capacitor 206 form a floating resonance circuit. In some embodiments, the capacitance of the outer capacitor 206 ranges from 5 pF to 1000 pF.

[0103] In some embodiments, the radiation structure 210 includes eight arms provided between an inner ring and an outer ring. The inner capacitor 206 is a low-impedance central ring and is coupled to the radiation structure 210. The inner capacitor 206 has an interconnection with the inductive drive coil 2010.

[0104] In some embodiments, the inductive structure of the radiation structure 210 and the inductive drive coil 2010 overlap. In other embodiments, the radiation structure 210 is inductively coupled to the plasma, but the power coupling between the circuit for the radiation structure 210 and the circuit for the inductive drive coil 2010 can be separated (e.g., the conductive offset 208 is an inductive coupling of the circuit for the radiation structure 210).

[0105] FIG. 21 shows a cross-sectional view of the multi-zone resonance structure 2100, which is similar to the multi-zone resonance structure 2000 (see FIG. 20 above), but is a detailed example of inductive power coupling with a capacitor 2105 added between the radiation structure 210 and the inductive drive coil 2010.

[0106] In some embodiments, the radiation structure 210 includes four arms provided between an inner ring and an outer ring. The capacitor 2105 between the radiation structure 210 and the inductive drive coil 2010 is formed by the inner ring of the radiation structure 210 and the loop of the inductive drive coil 2010, which are capacitively coupled across a gap filled with a dielectric. The dielectric can be air, atmosphere, ceramic, Teflon®, etc., or a combination thereof. Teflon® can maintain a more uniform spacing between the inner ring of the radiation structure 210 and the loop of the inductive drive coil 2010 and can reduce arc discharge between them. In some embodiments, the capacitor 1905 has a capacitance in the range of 1 pF to 100 pF.

[0107] In some embodiments, instead of the capacitor 2105, an inductive coupling is used between a common conductive structure (e.g., a conductive central ring or a part of the radiation structure 210) of the radiation structure 210 and the inductive drive coil 2010 based on the current direction at a given frequency. This inductive coupling between the common conductive structure of the radiation structure 210 and the inductive drive coil 2010 is a different inductive coupling method from the inductive coupling between the inductive drive coil and the arms of the radiation structure 210.

[0108] FIG. 22A shows a cross-sectional view of the multi-zone resonance structure 2200, which is a detailed example of capacitive power coupling in one embodiment of the multi-zone resonance structure 1100 described above with respect to FIG. 11. The excitation component using capacitive power coupling includes a capacitor 2006 formed by a conductive plate 2005 and a dielectric structure 2004, and a ground plane 202. In the example shown in FIG. 22A, the capacitor 2006 is at the inner edge of the outer resonance structure 502 close to the axis 510. However, the capacitor 2006 may also be at the outer edge of the outer resonance structure 502 far from the axis 510, or at any other suitable position.

[0109] In some embodiments, the outer resonance structure 502 and the inner resonance structure 504 are each a floating resonance circuit zone including its respective outer capacitor 206, its respective radiation structure 210, and its respective inner capacitor 206.

[0110] The capacitive coupling drives the radiation structure 210 by the capacitive coupling between the capacitor 2006 of the outer resonance structure 502 and the radiation structure 210. The capacitor 2006 is coupled to a power supply 1912 and a ground or matching circuit 1914 to drive the capacitor 2006 at a single or multiple frequencies. In some embodiments, one or more variable frequencies are supplied to the capacitor 2006. In some embodiments, the capacitor 206 of the outer resonance structure 502 is also capacitively coupled to the radiation structure 210 of the inner resonance structure 504.

[0111] In some embodiments, additional feeders and matching circuits are coupled to capacitor 206 of the inner resonant structure 504 to tune the resonant frequency of the inner resonant structure 504 using single-frequency driving. The matching circuit can include one or more tuning elements such as capacitors (either fixed or variable) or inductors. This may enable adjustment of the relative amounts of power supplied to the radiation structure 210 of the outer resonant structure 502 and the radiation structure 210 of the inner resonant structure 504 through the capacitive coupling of capacitor 2006. In some embodiments, a third zone (see, e.g., additional resonant structure 508, FIGS. 5E - 5G described above) exists, and separate respective feeders and matching circuits are coupled to the respective capacitors of the third zone to tune the resonant frequency of the third zone using single-frequency driving.

[0112] The radiation structure 210 of the inner resonant structure 504 is driven by mutual inductive coupling with the radiation structure 210 of the outer resonant structure 502. The respective radiation structures 210 are placed close enough to each other (e.g., separated by a distance in the range of 5 mm to 100 mm) to enable a strong mutual inductive coupling. In other embodiments, by overlapping the outer resonant structure 502 and the inner resonant structure 504, an inductive coupling can be provided between them, while the plasma coupling area can be reduced by separating the respective radiation structures 210 by a distance greater than 20 mm. In some embodiments, the mutual inductive coupling occurs at the resonant frequency of the inner resonant structure 504 and ignites the plasma 112 under the radiation structure 210 of the inner resonant structure 504. In some embodiments, the mutual inductive coupling occurs at the resonant frequency of the outer resonant structure 502 and ignites the plasma 112 under the radiation structure 210 of the outer resonant structure 502.

[0113] In some embodiments, the mutual inductive coupling occurs at the shared resonance frequency of the outer resonant structure 502 and the inner resonant structure 504, and ignites the plasma 112 under each of the respective radiation structures 210 of the outer resonant structure 502 and the inner resonant structure 504. By coupling a matching circuit to one or both of the outer resonant structure 502 and the inner resonant structure 504 and tuning its resonance frequency as the density of the plasma 112 changes, the resonance of the resonant structure can be maintained. The matching circuit can track the resonant structure using harmonic sensing, such as using an inductive coil sensor for both each respective feeder and the feeder of the matching circuit.

[0114] Figures 22B and 22C show examples of circuit diagrams of two matching circuits 2214 that couple the resonant structures to their respective RF sources 102. Each matching circuit 2214 includes a variable capacitor 2210 coupled in parallel with each of the outer resonant structure 502 and the inner resonant structure 504, and a variable capacitor 2212 coupled between each variable capacitor 2210 and its respective RF source 102. Figure 22B shows an example where the outer resonant structure 502 is coupled to each matching circuit 2214 through capacitors 206A and 206B, and the inner resonant structure 504 is coupled to each matching circuit 2214 through capacitors 206C and 206D. Figure 20C shows an example where the outer resonant structure 502 is coupled to each matching circuit 2214 through capacitor 206A, the inner resonant structure 504 is coupled to each matching circuit 2214 through capacitor 206D, and the common capacitor 206B / C of the outer resonant structure 502 and the inner resonant structure is coupled to both of the matching circuits 2214.

[0115] In some embodiments, the mutual inductive coupling includes simultaneously superimposing through the outer resonant structure 502 and the inner resonant structure 504, or pulsing and adjusting to use two frequencies that maintain the respective resonance control and balance of the outer resonant structure 502 and the inner resonant structure 504. For example, a multi-tone drive can be used to supply two frequencies through the capacitor 2006 (see FIG. 22A above). Note that according to FIGS. 15 and 16 above, multiple frequencies can be supplied using a multiple frequency generator having one RF source 102. In some embodiments, separate matching elements such as the variable capacitor 2210 and the variable capacitor 2212 are included in various configurations.

[0116] In some embodiments, the capacitor 2006 (see FIG. 22A above) is formed by the conductive plate 2005 and the dielectric structure 2004 within the inner resonant structure 504, whereby the capacitor capacitively couples to the radiation structure 210 of the inner resonant structure 504 rather than the radiation structure 210 of the outer resonant structure 502. FIG. 22D shows the radiation structure 210 of the outer resonant structure 502 driven by the mutual inductive coupling structure 2217. The mutual inductive coupling structure 2217 includes one or more inductors 2215 coupled to the radiation structure 210 of the inner resonant structure 504 and one or more inductors 2216 coupled to the radiation structure 210 of the outer resonant structure 502. The inductor 2215 is mutually coupled with the inductor 2216. The outer resonant structure 502 can include a tuning structure (e.g., a capacitor or an inductor coupled to a feeder and a matching circuit) to be tuned to match the resonance frequency of the inner resonant structure 504.

[0117] FIG. 23 shows a cross-sectional view of the multi-zone resonance structure 2100, which is a detailed example of inductive power coupling in one embodiment of the multi-zone resonance structure 700 described above with respect to FIG. 7. The inductive drive coil 2310 is within the outer resonance structure 502. The inductive drive coil 2310 can be separated from the generation of plasma by a distance in the range of 10 mm to 100 mm from the plasma chamber 106. For example, in the case of the bell-shaped dielectric plate 114 and the plasma chamber 106, a separation distance of about 10 mm can be achieved because the thickness of the dielectric plate 114 may be required to support a vacuum within the plasma chamber 106. In some embodiments, the separation distance is variable, and a mechanical actuator is used to adjust the relative height of the inductive drive coil 2310. The inductive drive coil 2310 acts as an excitation component that inductively couples with the radiation structure 210 of the outer resonance structure 502.

[0118] The inductive drive coil 2310 can have a plurality of coils arranged in a vertical or horizontal direction. In the embodiment according to FIG. 23, the inductive drive coil 2310 is a two-turn coil with the coils arranged in the horizontal direction. In other embodiments, the inductive drive coil 2310 is a two-turn coil with the coils stacked vertically. However, the inductive drive coil 2310 can be of any shape that couples to each radiation structure 210. For example, the inductive drive component may be an arc or line segment that matches the pattern of each radiation structure 210 instead of a coil. In some embodiments, the inductive drive coil 2310 is a pair of half-coils that each cover 180° of the azimuthal plane, and each half-coil has its own connection to a respective feeder and a ground or matching circuit.

[0119] The inductive drive coil 2310 is coupled to each respective feeder 1912 and each respective ground or matching circuit 1914. The inductive drive coil 2310 can receive a single or variable frequency through each respective feeder 1912.

[0120] The radiation structure 210 of the inner resonance structure 504 is driven by inductive coupling with the inductive drive coil 2310 to generate a magnetic field that couples to the outer resonance structure 502 and the inner resonance structure 504. The radiation structure 210 can be further driven by mutual inductive coupling with the radiation structure 210 of the outer resonance structure 502. The mutual inductive coupling in the multi-zone resonance structure 2300 can be the same as the mutual inductive coupling in the multi-zone resonance structure 2200 described above with respect to FIG. 22A, and the details will not be repeated here. The mutual inductive coupling between the radiation structure 210 of the inner resonance structure 504 and the radiation structure 210 of the outer resonance structure 502 can further include pulse modulation between different frequencies supplied by the inductive drive coil 2310.

[0121] Although not shown, the multi-zone resonance structure 2300 can include tuning elements (e.g., additional capacitors or inductors that can be variable) coupled to either or both of the outer resonance structure 502 or the inner resonance structure 504. The tuning elements may be able to tune the respective resonance frequencies of the resonance structures.

[0122] In some embodiments, the radiation structure 210 of the outer resonance structure 502 includes eight arms provided between the inner capacitor 206 and the outer capacitor 206 of the outer resonance structure 502. The inner capacitor 206 can be a low-impedance center ring coupled to the radiation structure 210 and having a mutual coupling with the inductive drive coil 2310.

[0123] In some embodiments, the inductive drive coil 2310 is within the inner resonance structure 504 rather than the outer resonance structure 502, such that the inductive drive coil 2310 inductively couples more strongly to the radiation structure 210 of the inner resonance structure 504 than to the radiation structure 210 of the outer resonance structure 502. The radiation structure 210 of the outer resonance structure 502 is driven by inductive coupling with the inductive drive coil 2310 and mutual inductive coupling with the radiation structure 210 of the inner resonance structure 504. In addition, there is a mutual inductive coupling between the inner resonance structure 504 and the outer resonance structure 502.

[0124] In some embodiments, the shield separates the outer resonant structure 502 and the inner resonant structure 504. The shield can be a cylindrical sheet made of a conductive material, as described above with respect to FIG. 9. In some embodiments, the shield replaces the inner ring of the conductive offset 208 of the outer resonant structure 502. The shield can be a floating part of the CLC circuit. For example, the shield can couple the capacitor 206 to the radiation structure 210 (see FIG. 3B above).

[0125] FIG. 24A shows a cross-sectional view of a multi-zone resonant structure 2400, which is similar to the multi-zone resonant structure 1900 described above with respect to FIG. 19, and an RF splitter 2402, which may also be called a matching box, is added. A single RF power input 2404 supplies power to the RF splitter 2402 from an RF source 102 (see FIG. 1 above), etc. The RF splitter 2402 divides the power among two or more feeders, such as between the feeder 1912A and the feeder 1912B, each receiving a single or variable frequency and supplying them to the inductive drive coil 1910A in the outer resonant structure 502 and the inductive drive coil 1910B in the inner resonant structure 504. The balance control of the feeders 1912A and 1912B can be provided by the matching circuits 1914A and 1914B of the RF splitter 2402, which may include LC circuits. Thus, the power split between the outer resonant structure 502 and the inner resonant structure 504 can be performed by superimposing interleaved pulses of two frequencies through the variable circuit elements of the RF splitter 2402 with the elements of the RF splitter 2402 that preferentially couple each frequency to either the outer resonant structure 502 or the inner resonant structure 504, or by a combination thereof.

[0126] FIG. 24B shows an example of a circuit diagram of an RF splitter 2402 which is an inductive power splitter. The inductive drive coil 1910A of the outer resonance structure 502 is coupled to the inductor L1, and the inductive drive coil 1910B of the inner resonance structure 504 is coupled to the inductor L2. The inductor L1 is inductively coupled to the inductor L3, and the inductor L2 is inductively coupled to the inductor L4. The inductor L3 is coupled to the RF source 102 at one end and coupled to ground with the capacitor 2406 interposed therebetween at the other end. The inductor L4 is coupled to the RF source 102 at one end and coupled to ground with the capacitor 2406 interposed therebetween at the other end. The inductors L3 and L4 can share the node coupled to the RF source 102. The capacitor 2406 can be a variable capacitor.

[0127] The inductive power coupling shown in FIGS. 24A and 24B is advantageous because by inductively coupling the inductor L1 to the inductive drive coil 1910A and the inductor L2 to the inductive drive coil 1710B, the inductive power drive becomes floating, making it possible to reduce the asymmetric effect of the coil grounded at one end. As a result, it is possible to reduce the undesirable high voltage that may be formed on the drive coil, thereby reducing the capacitive coupling to the plasma 112 when the inductive drive coil 1910 is near the dielectric plate 114. The floating inductive power coupling can maintain a uniform current and a uniform voltage in the cavity to achieve uniformity. The power coupling can also be changed by mutually controlling the inductance ratios of various inductive components (for example, the inductance ratio of the inductor L1 to the inductive drive coil 1910A, or the inductance ratio of the inductor L3 to the inductor L1). It should be recognized that the inductive power coupling shown in FIGS. 24A and 24B is a non-limiting example of a power splitting method, and it is possible to use any suitable power splitting method.

[0128] FIG. 25 shows a cross-sectional view of a multi-zone resonance structure 2500, which is a detailed example of capacitive power coupling in one embodiment of the multi-zone resonance structure 800 described above with respect to FIG. 8. Excitation components using capacitive power coupling are present in each of the outer resonance structure 502 and the inner resonance structure 504. The excitation components include respective capacitors 2006 formed by respective conductive plates 2005 and respective dielectric structures 2004, and a ground plane 202.

[0129] In the example shown in FIG. 25, the capacitors 2006 are at the respective outer edges of the outer resonance structure 502 and the inner resonance structure 504, close to the axis 510. However, either or both of the capacitors 2006 may also be at the respective inner edges of the outer resonance structure 502 and the inner resonance structure 504, close to the axis 510, or at any other suitable position.

[0130] Capacitive coupling drives the radiation structures 210 by capacitive coupling between the capacitors 2006 and the respective radiation structures 210 of the outer resonance structure 502 and the inner resonance structure 504. The capacitors 2006 are coupled to respective power feeders 1912 and a ground or matching circuit 1914 to drive the capacitors 2006 at single or multiple frequencies. In some embodiments, one or more variable frequencies are supplied to the capacitors 2006. In some embodiments, the power feeder 1912 is coupled to a single power source (e.g., RF source 102, see FIG. 1 above) through a power splitter.

[0131] In some embodiments, the capacitor 206 of the outer resonance structure 502 or the inner resonance structure 504 is coupled to a matching circuit that includes a tuning element (e.g., an inductor or capacitor that can be variable or fixed). The tuning element can be used to tune the respective resonance frequencies of the outer resonance structure 502 and the inner resonance structure 504, which may be advantageous for controlling the mutual inductive coupling between the respective radiation structures 210 of the outer resonance structure 502 or the inner resonance structure 504. For example, in order to reduce the mutual inductive coupling between the radiation structures 210, it may be advantageous to supply power to the outer resonance structure 502 and the inner resonance structure 504 at different frequencies through the respective capacitors 2006 or capacitors 206.

[0132] In some embodiments, the conductive plate 2005 is a separate conductive ring in each of the outer resonance structure 502 and the inner resonance structure 504. However, the conductive plate 2005 can have any suitable shape or arrangement.

[0133] Figures 26, 27, and 28 each show a cross-sectional view of a multi-zone resonance structure 2600, a multi-zone resonance structure 2700, and a multi-zone resonance structure 2800, which are additional detailed examples of capacitive power coupling in the embodiments of the multi-zone resonance structure 900 described above with respect to FIG. 9. The multi-zone resonance structure 2600, the multi-zone resonance structure 2700, and the multi-zone resonance structure 2800 are similar to the multi-zone resonance structure 2500 (see FIG. 25 above), and respective shields separating the outer resonance structure 502 and the inner resonance structure 504 are added. The shield can be a cylindrical sheet made of a conductive material, as described above with respect to FIG. 9.

[0134] As shown in FIG. 26, each shield 2602 of the multi-zone resonance structure 2600 is grounded between the outer resonance structure 502 and the inner resonance structure 504. For example, the shield 2602 can be coupled to the ground plane 202 by a conductive support or direct bonding, etc.

[0135] As shown in FIG. 27, each shield 2702 of the multi-zone resonance structure 2700 floats between the outer resonance structure 502 and the inner resonance structure 504. For example, the shield 2702 can be supported by a dielectric support coupled to the insulating structure 204.

[0136] As shown in FIG. 28, each shield 2802 of the multi-zone resonance structure 2800 is coupled to the conductive offset 208 of the outer resonance structure 502. In some embodiments, the shield 2802 replaces the inner ring of the conductive offset 208 of the outer resonance structure 502. The shield 2802 can be a floating portion of the CLC circuit. For example, the shield 2802 can couple the capacitor 206 to the radiation structure 210 (see FIG. 3B above).

[0137] Here, examples of embodiments of the present disclosure are summarized. Other embodiments can also be understood from the entire specification as well as from the claims of this application.

[0138] Example 1. An apparatus for plasma processing, comprising a first resonance structure coupled to a first RF generator through a first matching circuit, and a second resonance structure surrounding the first resonance structure and coupled to a second RF generator through a second matching circuit.

[0139] Example 2. The apparatus according to Example 1, wherein the first RF generator and the second RF generator are the same RF generator.

[0140] Example 3. The apparatus according to Example 1 or 2, wherein the first resonance structure has a cylindrical shape.

[0141] Example 4. The apparatus according to any one of Examples 1 to 3, further comprising a third resonance structure surrounding the second resonance structure.

[0142] Example 5. The apparatus according to one of Examples 1 to 4, wherein the first resonant structure is coupled to the ground plane through the first capacitor, and the second resonant structure is coupled to the ground plane through the second capacitor.

[0143] Example 6. The apparatus according to Example 5, wherein the first capacitor and the second capacitor are the same.

[0144] Example 7. The apparatus according to one of Examples 1 to 6, further comprising a shield between the first resonant structure and the second resonant structure.

[0145] Example 8. The apparatus according to Example 7, wherein the shield is grounded.

[0146] Example 9. The apparatus according to Example 7, wherein the shield is a floating portion of the CLC circuit.

[0147] Example 10. An apparatus for plasma processing, comprising: a first resonant structure that forms a first zone for a first plasma affected by the first resonant structure; and a second resonant structure that forms a second zone for a second plasma affected by the second resonant structure, the second zone surrounding the first zone.

[0148] Example 11. The apparatus according to Example 10, wherein the second resonant structure is driven by a first frequency through a first induction coil, and the first induction coil is located in the second resonant structure.

[0149] Example 12. The apparatus according to Example 11, wherein the radiation structure of the first resonant structure is driven by coupling with the radiation structure of the second resonant structure.

[0150] Example 13. The apparatus according to Example 11 or 12, wherein the first resonant structure is driven by a second frequency through a first induction coil.

[0151] Example 14. The apparatus according to Example 13, wherein the first frequency and the second frequency are supplied simultaneously.

[0152] Example 15. The apparatus according to Example 14, wherein the first frequency and the second frequency are supplied as interleaved pulses.

[0153] Example 16. The apparatus according to any one of Examples 11 to 15, wherein the first induction coil is floating.

[0154] Example 17. The apparatus according to Example 11, wherein the first resonant structure is a second induction coil, the second induction coil within the first resonant structure is driven by the second frequency through the second induction coil, and the first induction coil and the second induction coil are coupled to an RF power source through an RF splitter.

[0155] Example 18. The apparatus according to Example 17, wherein the respective powers supplied to the first induction coil and the second induction coil can be configured by changing the inductance or capacitance of a variable component of the RF splitter.

[0156] Example 19. An apparatus for plasma processing, comprising: a first cavity having a first resonant frequency and coupled to a conductive surface through a first capacitor; and a second cavity having a second resonant frequency, the second cavity surrounded by the first cavity and coupled to the conductive surface through a second capacitor.

[0157] Example 20. The apparatus according to Example 19, wherein the first resonant frequency is the same as the second resonant frequency.

[0158] Although described in detail, it should be understood that various changes, substitutions, and modifications can be made without departing from the spirit and scope of the present disclosure as defined by the appended claims. In the various figures, the same reference numerals are assigned to the same elements. Furthermore, the scope of the present disclosure is not intended to be limited to the specific embodiments described herein, and those skilled in the art will readily recognize from the present disclosure that processes, machines, manufactures, compositions of matter, means, methods, or steps that currently exist or are later developed can perform substantially the same functions or achieve substantially the same results as the corresponding embodiments described herein. Accordingly, the appended claims are intended to include such processes, machines, manufactures, compositions of matter, means, methods, or steps within their scope.

[0159] Accordingly, the present specification and drawings are to be regarded as merely illustrative of the present disclosure as defined by the appended claims, and it is intended to cover any and all modifications, variations, combinations, or equivalents that fall within the scope of the present disclosure. For example, it should be recognized that the physical placement and arrangement of components in various embodiments of a plasma processing system or a resonant structure are non-limiting. For example, although the resonant structure is arranged between the RF source and the plasma processing system in various illustrations, this arrangement is non-limiting, and these components may be arranged near, above, or below other components while remaining within the scope of the present disclosure.

Claims

1. An apparatus for plasma processing, comprising: a first resonant structure coupled to a first RF generator through a first matching circuit; and a second resonant structure surrounding the first resonant structure and coupled to a second RF generator through a second matching circuit.

2. The apparatus according to claim 1, wherein the first RF generator and the second RF generator are the same RF generator.

3. The apparatus according to claim 1, wherein the first resonant structure has a cylindrical shape.

4. The apparatus according to claim 1, further comprising a third resonant structure surrounding the second resonant structure.

5. The apparatus according to claim 1, wherein the first resonant structure is coupled to a ground plane through a first capacitor, and the second resonant structure is coupled to the ground plane through a second capacitor.

6. The apparatus according to claim 5, wherein the first capacitor and the second capacitor are the same.

7. The apparatus according to claim 1, further comprising a shield between the first resonant structure and the second resonant structure.

8. The apparatus according to claim 7, wherein the shield is grounded.

9. The apparatus according to claim 7, wherein the shield is a floating part of a CLC circuit.

10. An apparatus for plasma processing, comprising: a first resonant structure forming a first zone for a first plasma affected by the first resonant structure; and a second resonant structure forming a second zone for a second plasma affected by the second resonant structure and surrounding the first zone.

11. The apparatus according to claim 10, wherein the second resonant structure is driven by a first frequency through a first induction coil, and the first induction coil is located in the second resonant structure.

12. The apparatus according to claim 11, wherein a radiation structure of the first resonant structure is driven by coupling with a radiation structure of the second resonant structure.

13. The apparatus according to claim 11, wherein the first resonant structure is driven by a second frequency through the first induction coil.

14. The apparatus according to claim 13, wherein the first frequency and the second frequency are supplied simultaneously.

15. The apparatus according to claim 14, wherein the first frequency and the second frequency are supplied as interleaved pulses.

16. The apparatus according to claim 11, wherein the first induction coil is floating.

17. The first resonant structure is a second induction coil, and is driven by a second frequency through the second induction coil in the first resonant structure, and the first induction coil and the second induction coil are coupled to an RF power source through an RF splitter. The apparatus according to claim 11.

18. The apparatus according to claim 17, wherein the respective powers supplied to the first induction coil and the second induction coil can be configured by changing the inductance or capacitance of a variable component of the RF splitter.

19. An apparatus for plasma processing, A first cavity having a first resonant frequency, the first cavity being coupled to a conductive surface through a first capacitor, A second cavity having a second resonant frequency, the second cavity being surrounded by the first cavity, the second cavity being coupled to the conductive surface through a second capacitor. An apparatus comprising:

20. The apparatus according to claim 19, wherein the first resonant frequency is the same as the second resonant frequency.

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