Antenna planar magnet for improved performance

Abstract

According to one embodiment, a plasma processing system includes a plasma chamber, a planar antenna, a dielectric plate, and a plurality of magnets. The planar antenna is configured to generate plasma in the plasma chamber. The dielectric plate is disposed between the plasma chamber and the planar antenna. The magnet is disposed vertically above an outer surface of the dielectric plate facing the plasma chamber.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Non-Provisional Patent Application No. 18 / 162,876, filed February 1, 2023, which is incorporated herein by reference in its entirety.

[0002] FIELD OF THE DISCLOSURE The present disclosure relates generally to semiconductor processing techniques and, in particular embodiments, to magnets used in plasma processing systems. [Background technology]

[0003] Plasma processing is widely used in the semiconductor industry in the manufacturing and fabrication 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 within the chamber. The heated electrons ignite a plasma that treats substrates in processes such as etching, deposition, oxidation, and sputtering.

[0004] Generally, during operation of a plasma processing system, the impedance of the plasma in the plasma chamber varies significantly. For example, plasma impedance variations can be due to operating frequency, changes in temperature and pressure in the plasma chamber, increases or decreases in gas flow rates, etc. To match the impedance of the plasma chamber to the impedance of the transmission line, a matching network is utilized. Auto-tuning algorithms typically control the matching network more quickly than a human can. Unfortunately, existing tuning algorithms struggle with matching at low or very low pressures.

[0005] Furthermore, plasma stability is problematic at low pressures (e.g., below 10 mTorr), and the plasma density is too low to be practical for processing semiconductor wafers at low and ultra-low pressures.

[0006] Therefore, devices and systems that allow operation of plasma chambers at low and ultra-low pressure conditions are desirable. Summary of the Invention [Means for solving the problem]

[0007] Technical advantages are generally achieved by embodiments of the present disclosure, which describe a magnet in a plasma processing system.

[0008] A first aspect relates to a plasma processing system. The plasma processing system includes a plasma chamber, a planar antenna, a dielectric plate, and a plurality of magnets. The planar antenna is configured to generate plasma in the plasma chamber. The dielectric plate is disposed between the plasma chamber and the planar antenna. The magnet is disposed vertically above an outer surface of the dielectric plate facing the plasma chamber.

[0009] In a first implementation of such a plasma processing system according to the first aspect, one or more of the magnets of the plurality of magnets is a permanent magnet, an electromagnet, an electro-permanent magnet (EPM), or a combination thereof.

[0010] In such a second implementation of the plasma processing system according to the first aspect, or any preceding implementation of the first aspect, one or more magnets of the plurality of magnets have a polar axis perpendicular to the dielectric plate, a polar axis parallel to the dielectric plate, or a combination thereof.

[0011] In such a third implementation of the plasma processing system according to the first aspect, or any preceding implementation of the first aspect, one or more magnets of the plurality of magnets are arranged along a ring parallel to the planar antenna, and further, one or more magnets of the plurality of magnets have a polar axis perpendicular to the ring, a polar axis tangent to the ring, or a combination thereof.

[0012] In such a fourth implementation of the plasma processing system according to the first aspect, or any previous implementation of the first aspect, the plasma processing system further includes a housing structure, an antenna disposed within the housing structure, and a dielectric plate positioned between the housing structure and the plasma chamber.

[0013] In such a fifth implementation of the plasma processing system according to the first aspect, or any preceding implementation of the first aspect, one or more magnets of the plurality of magnets are disposed external to the housing structure.

[0014] In such a sixth implementation of the plasma processing system according to the first aspect, or any preceding implementation of the first aspect, one or more magnets of the plurality of magnets are arranged in a plane parallel to the planar antenna.

[0015] In such a seventh implementation of the plasma processing system according to the first aspect, or any preceding implementation of the first aspect, the plane is vertically adjustable from an outer surface of the dielectric plate facing the plasma chamber to the second plane, and further, the planar antenna is disposed between the second plane and the dielectric plate.

[0016] A second aspect relates to a plasma processing system. The plasma processing system includes a plasma chamber, an antenna, a dielectric plate, and a plurality of magnets. The plasma chamber has a top surface and a bottom surface opposite the top surface. The antenna is configured to generate plasma in a plasma generation region within the plasma chamber. The dielectric plate is disposed between the plasma chamber and the antenna. Furthermore, the top surface of the plasma generation region is a surface corresponding to the bottom surface of the dielectric plate adjacent to the top surface of the plasma chamber. The magnet is disposed vertically above the top surface of the plasma generation region in a direction from the bottom surface of the plasma chamber toward the top surface of the plasma chamber. Furthermore, one or more positions or polar axes of the magnet are configurable.

[0017] In a first implementation of such a plasma processing system according to the second aspect, one or more of the magnets of the plurality of magnets is a permanent magnet, an electromagnet, an electromagnet (EPM), or a combination thereof.

[0018] In such a second implementation of the plasma processing system according to the second aspect, or any preceding implementation of the second aspect, one or more magnets of the plurality of magnets have a polar axis perpendicular to the plasma, a polar axis parallel to the plasma, or a combination thereof.

[0019] In such a third implementation of the plasma processing system according to the second aspect, or any prior implementation of the second aspect, the antenna is donut-shaped. Further, the first subset of magnets is disposed on a first plane on the outer periphery of the antenna and parallel to the antenna. Further, the second subset of magnets is disposed on a second plane within the inner periphery of the antenna and parallel to the antenna. In an embodiment, the first plane and the second plane are the same plane.

[0020] In such a fourth implementation of the plasma processing system according to the second aspect, or any preceding implementation of the second aspect, the magnets of the first subset of magnets are symmetrically arranged around the outer periphery of the antenna, and further, the magnets of the second subset of magnets are symmetrically arranged within the inner periphery of the antenna.

[0021] In such a fifth implementation of the plasma processing system according to the second aspect, or any preceding implementation of the second aspect, determining the magnet placement is based on changes in density, stability, pressure, ignition stability of the plasma, changes in the tunability of a matching network coupled to the antenna, or a combination thereof.

[0022] In such a sixth implementation of the plasma processing system according to the second aspect, or any preceding implementation of the second aspect, the plasma is a low-pressure plasma corresponding to a pressure of 10 milliTorr (mTorr) or less.

[0023] A third aspect relates to a method of operating a plasma processing system, the plasma processing system including a plasma chamber, an antenna, a dielectric plate, and a plurality of magnets. The antenna is used to generate plasma in the plasma chamber. The dielectric plate is disposed between the plasma chamber and the antenna. The magnet is also disposed vertically above an outer surface of the dielectric plate facing the plasma chamber.

[0024] The method includes setting a plasma processing operation for a plasma processing system, measuring one or more parameters associated with the plasma processing system, and adjusting the placement of one or more magnets based on the plasma processing operation and the one or more parameters.

[0025] In such a first implementation of the method according to the third aspect, the one or more parameters are one or more of plasma stability, electron temperature, plasma ignition stability, plasma density, or tunability of a matching network coupled to the antenna.

[0026] In such a second implementation of the method according to the third aspect, or any preceding implementation of the third aspect, one or more magnets of the plurality of magnets are stationary electromagnets, and further, adjusting the position of the one or more magnets includes enabling, disabling, adjusting, or reversing a current in one or more of the stationary electromagnets.

[0027] In such a third implementation of the method according to the third aspect, or any preceding implementation of the third aspect, one or more of the magnets are permanent magnets disposed on a mechanical structure parallel to an outer surface of the dielectric plate. Further, adjusting the arrangement of the one or more magnets includes vertically shifting the mechanical structure between a first plane and a second plane. The first plane is the outer surface of the dielectric plate, and the second plane is a plane perpendicular to and above the antenna.

[0028] In such a fourth implementation of the method according to the third aspect, or any preceding implementation of the third aspect, the adjusting includes determining the magnet configuration using a lookup table having multiple configurations of the magnet based on the plasma processing operation and the one or more parameters.

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

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

[0031] [Figure 1] 1 is a diagram of an embodiment of a plasma processing system. [Figure 2A] 1 is a diagram of an embodiment of a plasma processing system having vertical plane placement options for various magnet configurations. [Figure 2B] 10A and 10B are top views of possible magnet arrangements on a plane. [Figure 3] FIG. 10 is a top view of one embodiment of a magnet arrangement. [Figure 4] FIG. 10 is a top view of one embodiment of a magnet arrangement. [Figure 5] FIG. 10 is a top view of one embodiment of a magnet arrangement. [Figure 6] FIG. 10 is a top view of one embodiment of a magnet arrangement. [Figure 7] FIG. 10 is a top view of one embodiment of a magnet arrangement. [Figure 8] FIG. 1 is a block diagram of a plasma processing system according to one embodiment. [Figure 9] 1 is a flowchart of an embodiment of a method for adjusting a magnet configuration of a plasma processing system. DETAILED DESCRIPTION OF THE INVENTION

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

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

[0034] In one embodiment, the low pressure is 1 milliTorr (mTorr) or less. In one embodiment, the low pressure condition is 10 mTorr or less.

[0035] Although aspects of the present invention are described primarily in the context of plasma chambers for processing substrates, aspects of the present invention may be applicable to fields outside the semiconductor industry as well. For example, plasma can be used to treat and modify surface properties through the addition of functional groups, such as treating surfaces for paint deposits by converting a hydrophobic surface to a hydrophilic surface. Regardless of the industry, it is desirable to have an apparatus that enables reliable operation of plasma chambers at low (and ultra-low pressure) plasma conditions.

[0036] In various embodiments, the arrangement of various components and magnets is shown symmetrical, e.g., to provide uniformity within the system. However, it should be understood that such symmetry is not required and that asymmetric configurations may be intentionally introduced, e.g., to compensate for non-uniformities within the system or to create skew chamber effects.

[0037] Typically, a radiating antenna is used to radiate RF waves, which generate an electromagnetic field within the plasma chamber to ignite and sustain a plasma within the plasma chamber. The impedance associated with the plasma generated within the plasma chamber corresponds to the load on the radiating antenna during its operation. The impedance of the plasma may vary based on, for example, changes in pressure, temperature, or operating conditions. Typically, a matching network (automatic or manual) coupled to the radiating antenna is used to minimize losses (i.e., reflected power) as load conditions change.

[0038] Plasmas generated at low pressure (i.e., low-pressure plasmas) are used, for example, to etch semiconductor wafers or form thin films in plasma chambers. Traditionally, operation of plasma chambers has suffered from various problems associated with low-pressure plasma conditions.

[0039] For example, at low pressures, plasma stability is reduced, plasma density is too low for process viability, plasma ignition is unreliable, etc. In addition, current algorithms and matching networks have not been fully developed to respond to the load conditions presented at low pressure conditions in existing plasma processing systems.

[0040] Embodiments of the present disclosure provide systems and methods that improve plasma stability, increase plasma density, enhance ignition stability, and boost matching network tuning compatibility at low pressures (i.e., under pulsed and continuous wave (CW) conditions), thus extending the performance of existing systems into the very low plasma range.

[0041] In various embodiments, magnets are used to improve plasma density, plasma stability, plasma ignition stability, and tuning compatibility of matching networks at low pressures. This disclosure provides various configurations of magnet placement relative to a plasma processing system. The magnets can be permanent magnets, electromagnets, electro-permanent magnets (EPMs), or any combination thereof.

[0042] In general, permanent magnets are easier to implement in existing plasma processing systems. Permanent magnets can be placed in or around a plasma processing system with minimal redesign. Furthermore, permanent magnets are less expensive and easier to control compared to electromagnets. However, electromagnets increase the options for controlling the overall magnet configuration profile within a system. The polarity of the electromagnet can be easily selected, for example, by reversing the current through the electromagnet. Furthermore, the electromagnet can be enabled or disabled, or the strength of the magnet can be adjusted, for example, by controlling the current through the electromagnet.

[0043] In an embodiment, the plurality of magnets are disposed above a plasma generating region of the plasma processing system. In an embodiment, the uppermost boundary of the plasma generating region is at the interface between the plasma chamber and a dielectric plate separating the plasma chamber from the housing and includes a radiating antenna. In an embodiment, the plurality of magnets are disposed in a plane parallel to the radiating antenna and the dielectric plate.

[0044] The magnets are arranged in a plane substantially coplanar with the dielectric plate, between the radiating antenna and the dielectric plate, substantially coplanar with the radiating antenna, above the radiating antenna and the dielectric plate but below the top surface of the housing, or above the radiating antenna, the dielectric plate, and the top surface of the housing. In each configuration, the magnets are arranged above the plasma generation region and the plasma chamber. In some embodiments, the magnets are arranged outside the housing. In some embodiments, the magnet arrangement is fixed. In some embodiments, the magnets can be moved horizontally from one plane to another or within the same plane using electrical or mechanical devices. In some embodiments, the magnets can be arranged in two or more planes. In some embodiments, a subset of the magnets can be disabled while the remaining subset of magnets remains enabled. In some embodiments, some magnets are radially aligned with each other, while in other embodiments, the magnets are arranged in a radially staggered manner. In some embodiments, the entirety of the magnets can be arranged in a single plane.

[0045] In some embodiments, the magnets have a polar axis perpendicular to the top of the plasma chamber. In some embodiments, the magnets have a polar axis parallel to the top of the plasma chamber. In some embodiments, the magnets are arranged in a ring pattern. In some embodiments, the magnets can have polarities either perpendicular or tangential to the ring. In embodiments, multiple subsets of magnets are arranged in different configurations. In some embodiments, the magnets have an off-axis orientation (e.g., angled), for example, to induce bulk plasma.

[0046] The magnets may be positioned around the radiating antenna, around the periphery, the inner periphery, the center, concentric circles, or combinations thereof, these and further details are discussed in more detail below.

[0047] Figure 1 shows a diagram of one embodiment of a plasma processing system 100. The plasma processing system 100 includes an antenna 102, a housing structure 104, a plasma chamber 106, and an optional dielectric plate 114, which may (or may not) be arranged as shown in Figure 1. Additionally, the plasma processing system 100 may include additional components not shown in Figure 1.

[0048] In an embodiment, the antenna 102 is coupled to an RF source 101. The RF source 101 includes an RF power source, which may include a generator circuit and a matching circuit (not shown). The RF source 101 is coupled to the antenna 102 via a power transmission line, such as a coaxial cable. The RF source 101 provides forward RF waves to the antenna 102 that are radiated toward the plasma chamber 106.

[0049] In an embodiment, the plasma chamber 106 includes a substrate holder 108. As shown, a substrate 110 is disposed 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 for removing by-products from the plasma chamber 106 by selective control of gas flow rates therein. In an embodiment, the pump outlets 116 are positioned near (e.g., below / around the periphery of) the substrate holder 108 and the substrate 110. In an embodiment, the plasma chamber 106 may include additional substrate holders (not shown). In an embodiment, the arrangement of the substrate holders 108 may differ from that shown in FIG. 1 . Thus, the number and location of the substrate holders 108 are non-limiting.

[0050] In an embodiment, the antenna 102 radiates an electromagnetic field toward the plasma chamber 106. The radiated electromagnetic field generates an azimuthally symmetric, high-density plasma in the plasma generating region 112 with a low capacitively coupled electric field.

[0051] In an embodiment, the antenna 102 is a planar antenna as disclosed in further detail in, for example, U.S. patent application Ser. Nos. 17 / 664,607, 17 / 649,823, 17 / 748,737, 17 / 985,360, and 18 / 146,253, all of which are incorporated herein by reference.

[0052] In an embodiment, antenna 102 is an inductively coupled antenna, such as a flat spiral wound planar coil (ie, a stovetop antenna).

[0053] For illustrative purposes, the antenna 102 may be envisioned as a donut-shaped structure in an embodiment.

[0054] In one embodiment, antenna 102 includes an arm connected to a capacitive structure that creates azimuthal symmetry. In an embodiment, the excitation frequency of antenna 102 is in the radio frequency range (10-400 MHz), although this is not limiting and other frequency ranges may be contemplated as well. For example, aspects of the invention disclosed herein apply equally to applications in the microwave frequency range.

[0055] In an embodiment, the antenna 102 includes a resonating element, which may be an arm electrically connected to a capacitive structure, the arm and the capacitive structure resonating with the electromagnetic waves provided by the RF source 101.

[0056] In an embodiment, the resonating element sustains a standing electromagnetic wave. The resonating element is positioned adjacent to and parallel to the dielectric plate 114 so that the oscillating magnetic field from the resonating element penetrates into the plasma chamber 106. The time-varying magnetic field induces a time-varying electric field that transfers energy to the plasma electrons.

[0057] In an embodiment, RF source 101 couples energy into an interface of antenna 102 to generate a standing electromagnetic wave from antenna 102. RF source 101 is coupled to the interface via a transmission line in an embodiment. The interface desirably maintains the same or greater symmetry under rotation about an axis of symmetry than the elements of antenna 102.

[0058] Additionally, a housing structure 104 is shown surrounding the antenna 102. The housing structure 104 is a conductive structure that is electrically coupled to, and therefore RF grounded, the RF ground of the RF source 101. In an embodiment, the housing structure 104 includes an opening for coupling an RF feed path from the RF source 101 to the antenna 102.

[0059] In an embodiment, the housing structure 104 is positioned adjacent to the top of the plasma chamber 106 such that the dielectric plate 114 is sandwiched between the housing structure 104 and the plasma chamber 106. Thus, the antenna 102 generates electromagnetic waves that radiate through the dielectric plate 114 toward the plasma chamber 106.

[0060] In an embodiment, the antenna 102 is separated from the plasma chamber 106 by a dielectric plate 114, which is typically made of a dielectric material. The dielectric plate 114 separates the low-pressure environment within the plasma chamber 106 from the outside atmosphere. It should be understood that the antenna 102 can be positioned directly adjacent to the dielectric plate 114. In an embodiment, the antenna 102 is separated from the plasma chamber 106 by air. In an embodiment, the properties of the dielectric plate 114 are selected to minimize reflections of RF waves from the plasma chamber 106. In another embodiment, the antenna 102 is embedded within the dielectric plate 114. In an embodiment, the dielectric plate 114 is disk-shaped.

[0061] The dielectric plate 114 includes a first outer surface and a second outer surface. The first outer surface faces the plasma chamber 106. The second outer surface faces the antenna 102. The second outer surface is vertically above the first outer surface.

[0062] In one embodiment, the antenna 102 couples RF power from the RF source 101 into the plasma chamber 106 to process the substrate 110. In particular, the antenna 102 radiates electromagnetic waves in response to a forward RF wave being supplied from the RF source 101. The radiated electromagnetic waves enter the plasma chamber 106 from the atmosphere side (i.e., the antenna 102 side) of the dielectric plate 114. The radiated electromagnetic waves generate an electromagnetic field within the plasma chamber 106. The generated electromagnetic field ignites and sustains a plasma in the plasma generation region 112 by transferring energy to free electrons within the plasma chamber 106. The generated plasma can be used, for example, to selectively etch or deposit material on the substrate 110.

[0063] In an embodiment, the plasma generating region 112 is directly below the portion of the dielectric plate 114 closest to the plasma chamber 106. In an embodiment, the top surface of the plasma generating region 112 corresponds to the plane where the outer surface of the dielectric plate 114 faces the plasma chamber 106.

[0064] 1, the antenna 102 is external to the plasma chamber 106. However, in embodiments, the antenna 102 may be located inside the plasma chamber 106. In such embodiments, the plasma generation region 112 is directly below the portion of the antenna 102 closest to the plasma chamber 106.

[0065] As disclosed herein and described in further detail below, the plasma generation region 112 is used as a reference point for the magnet configuration.

[0066] In an embodiment, the operating frequency of antenna 102 is between 5 and 100 megahertz (MHz). In an embodiment, the power delivered by antenna 102 is in the range of 10 to 5000 watts (W), which is determined by various factors such as the distance from antenna 102, the impedance value, etc.

[0067] As used herein, a "vertical direction" with respect to a plasma processing system refers to a direction from the housing structure 104 to the plasma chamber 106 through the dielectric plate 114. The terms "above" and "below" with respect to a plasma processing system are defined in the same context. For example, the plasma chamber 106 is below the dielectric plate 114, the antenna 102, and the housing structure 104; the dielectric plate 114 is below the antenna 102 and the housing structure 104 but above the plasma chamber 106; the antenna 102 is above the dielectric plate 114 and the plasma chamber 106 but below the top surface of the housing structure 104; and the housing structure 104 has a top surface that is above the plasma chamber 106, the dielectric plate 114, and the antenna 102.

[0068] As used herein, "horizontal direction" with respect to a plasma processing system refers to a direction perpendicular to the vertical direction and along the housing structure 104 or the plasma chamber 106 from a first vertical sidewall to a second vertical sidewall of either structure.

[0069] The use of these terms is intended to enhance clarity and is not intended to impose architectural limitations on the embodiments of the present disclosure.

[0070] 2A shows a diagram of one embodiment of plasma processing system 100 with vertical planar placement options 202-210 for various magnet configurations. In all magnet configurations, the magnets are positioned above plasma generation region 112. In an embodiment, plasma generation region 112 is directly below the portion of dielectric plate 114 closest to plasma chamber 106. In an embodiment, the top boundary of plasma generation region 112 is at the interface between plasma chamber 106 and dielectric plate 114, which separates plasma chamber 106 from housing structure 104.

[0071] Placing the magnets above the plasma region improves plasma generation without significantly affecting the plasma energy distribution at the substrate. Magnets placed around the plasma region can, for example, cause undesirable etch profile tilt for parts of the wafer. Magnets can also be placed at a vertical distance from the plasma, where the field does not affect plasma density or uniformity but still improves ignition. In electromagnet embodiments, the magnets can be enabled only for ignition and then turned off.

[0072] In embodiments, the magnets are arranged in one or more placement options 202-210 to improve plasma density, plasma ignition stability, increase azimuthal uniformity, enhance the radial density profile of the plasma, and the like.

[0073] In an embodiment, each magnet is positioned above the outer surface of the dielectric plate 114 facing the plasma chamber 106. Each magnet is positioned vertically above the outer surface of the dielectric plate 114 along a direction from the plasma chamber 106 toward the antenna 102. In an embodiment, the magnets are positioned horizontally in the same vertical plane. These horizontal positions can be inside or outside the housing 104.

[0074] In an embodiment, the region below the outer surface of the dielectric plate 114 along the direction from the dielectric plate 114 to the substrate holder 108 is defined herein as the plasma generation region.

[0075] In an embodiment, the antenna 102 is substantially parallel (i.e., less than 5% skew) with the dielectric plate 114, the substrate holder 108, and the substrate 110. In such an embodiment, the plasma generated in the plasma chamber 106 may be symmetric and uniform.

[0076] In embodiments, the magnets are arranged on a plane identified as one of the arrangement options 202 through 210. In any of these embodiments, the plane associated with a set of magnets is defined as the plane located at the bottom-most part of the magnets (i.e., the side closest to the dielectric plate 114 and the plasma chamber 106) and parallel to the dielectric plate 114.

[0077] One or more magnets positioned or enabled (e.g., within an electromagnet case) in one or more of the positioning options 202-210 induce a magnetic field within the plasma chamber. In embodiments, the magnetic field strength can be varied by changing the distance between the magnet and the plasma, by enabling or disabling a subset of the magnets (e.g., within an electro-permanent magnet case), or by adjusting the current in the electromagnet case.

[0078] In embodiments, the magnetic field is a direct current (DC) magnetic field. In other embodiments, the magnetic field is oscillating. In embodiments, the magnetic field is pulsed. In embodiments, the magnetic field is permanent (e.g., when the magnet is a permanent magnet). In embodiments, the magnetic field can be disabled (e.g., when the magnet is an electromagnet).

[0079] The plane of the antenna 102 is defined as the plane parallel to the dielectric plate 114 positioned at the bottom-most part of the antenna 102 (ie, the side closest to the dielectric plate 114).

[0080] The plane of the dielectric plate 114 is defined as the bottom surface of the dielectric plate 114 (ie, the surface at the plasma interface).

[0081] A first placement option 202 of the magnet is defined as being substantially coplanar with the plane of the antenna 102. When placed on a plane parallel to the dielectric plate 114, corresponding to the first placement option 202, the vertical distance from the bottom surface of the magnet to the dielectric plate 114 is the same as the vertical distance from the bottom surface of the antenna 102 to the dielectric plate 114.

[0082] A second placement option 204 for the magnet is defined as being on a plane above the plane of the antenna 102 but below the top surface of the housing structure 104 (i.e., the surface furthest from the dielectric plate 114). When placed on a plane parallel to the dielectric plate 114, corresponding to the second placement option 204, the vertical distance from the bottom surface of the magnet to the dielectric plate 114 is greater than the vertical distance from the bottom surface of the antenna 102 to the dielectric plate 114, but less than the distance from the top surface of the housing structure 104 to the dielectric plate 114.

[0083] A third placement option 206 for the magnet is defined as being on a plane below the plane of the antenna 102 but above the dielectric plate 114. When placed on a plane parallel to the dielectric plate 114, corresponding to the third placement option 206, the vertical distance from the bottom surface of the magnet to the dielectric plate 114 is less than the vertical distance from the bottom surface of the antenna 102 to the dielectric plate.

[0084] A fourth placement option 208 for the magnet is defined as being on a plane above the top surface of the housing structure 104 (i.e., the surface furthest from the dielectric plate 114). When placed on a plane parallel to the dielectric plate 114, which corresponds to the fourth placement option 208, the vertical distance from the magnet to the dielectric plate 114 is greater than the vertical distance from the top surface of the housing structure 104 to the dielectric plate 114.

[0085] A fifth placement option 210 for the magnet is defined as being substantially coplanar with either surface of the dielectric plate 114 or between two surfaces of the dielectric plate.

[0086] In each of the placement options 202-210, a magnet is positioned at or above the dielectric plate 114 (i.e., corresponding to the fifth placement option 210). In embodiments, one or more magnets are positioned within the housing structure 104 at any of the vertical positions 202-210. In embodiments, one or more magnets are positioned on the external housing structure 104 at any of the vertical positions 202-210. In embodiments, one or more magnets are positioned within the housing structure 104 at any of the vertical positions 202-210, while one or more magnets are positioned external to the housing structure 104 at any of the vertical positions 202-210.

[0087] In one embodiment, all of the magnets are positioned on only a single plane identified as one of the identified placement options 202-210. In another embodiment, the magnets are positioned on a plane identified as one of the identified placement options 202-210. In some embodiments, at least one magnet is positioned on a plane identified as one of the identified placement options 202-210.

[0088] Embodiments of the present disclosure provide a plasma processing system 100 having a magnet that is in a plane parallel to, but not necessarily in the same plane as, the antenna 102 .

[0089] In one embodiment, the magnet can be moved mechanically or electronically in its entirety from one placement option to another (i.e., vertically). In one embodiment, the magnet can be moved mechanically or electronically in its entirety across a plane (i.e., horizontally) corresponding to one of the identified placement options 202-210. For example, the magnet can be on one or more structures or can be mounted on one or more structures that can be moved manually or automatically vertically or across a plane from one placement option to another.

[0090] In one embodiment, electromagnets or electro-permanent magnets are positioned in the identified placement options 202-210. In such an embodiment, a subset or all of the magnets may be enabled or disabled in one or more of the identified placement options. Thus, in a first configuration, only the electromagnets or electro-permanent magnets located in the first placement option 202 are enabled, in a second configuration, only the electromagnets or electro-permanent magnets located in the second placement option 204 are enabled, and so on. In some embodiments, electromagnets or electro-permanent magnets are enabled in more than one placement option 202-210 simultaneously.

[0091] In one embodiment, one or more permanent magnets are positioned asymmetrically (e.g., not aligned along the vertical center point) in one or more of placement options 202-210 to compensate for plasma asymmetry, for example, generated by an antenna or plasma chamber.

[0092] In one embodiment, one or more electromagnets or electro-permanent magnets are activated asymmetrically (e.g., not aligned along a vertical center point) in one or more of placement options 202-210 to compensate for plasma asymmetry, for example, generated by an antenna or plasma chamber.

[0093] In one embodiment, the permanent magnets are positioned symmetrically (e.g., aligned along a vertical center point) in one or more of the placement options 202-210 to avoid plasma asymmetries, for example, generated by an antenna or plasma chamber.

[0094] In one embodiment, the electromagnets or electro-permanent magnets are activated symmetrically (e.g., aligned along a vertical center point) in one or more of the placement options 202-210 to avoid plasma profile tilt, for example, during an etching procedure.

[0095] The determination of magnet placement, quantity, and strength varies based on the operating configuration of the plasma processing system.

[0096] For example, one factor to be considered may be the difference between the Larmor radius and the scale length of the plasma chamber 106, taking into account the flux density of the generated magnetic field.

[0097] Charged particles (e.g., electrons) in a magnetic field move in a spiral or helical motion (i.e., gyrations) along a direction parallel to the magnetic field. The transverse radius of the helical path traversed by the charged particle is called the Larmor radius. The Larmor radius of an electron is proportional to the inverse of the magnetic flux density of the magnetic field.

[0098] In an embodiment, the Larmor radius is preferably small compared to the scale length of the plasma chamber 106. For example, when the magnetic flux density is 1 Gauss, the Larmor radius is relatively large and comparable to the size of the plasma chamber 106. Therefore, in this example, the effect of the magnetic field on the charged particles in the plasma chamber 106 is small.

[0099] In contrast, if the magnetic flux density is, say, 10 Gauss, the Larmor radius will be smaller in magnitude. In this example, charged particles are separated by the magnetic field lines, and therefore the effect of the magnetic field will be stronger.

[0100] However, as the magnetic field is increased, there is a limit to the change in the behavior of the plasma within the plasma chamber 106. Therefore, there is a point where increasing the magnetic field has a negligible effect.

[0101] As another example, another factor that can be considered is magnetic field strength. The frequency of electron rotation in a magnetic field is linearly dependent on the strength of the magnetic field. For example, doubling the magnetic field strength can double the rotation speed of electrons. Furthermore, if the frequency of the RF field is synchronized (i.e., matches) with the rotation speed, energy transfer from the RF field to the electrons is enhanced (i.e., electron cyclotron resonance).

[0102] Other factors to consider when selecting magnet placement, quantity, and strength include, for example, the type of antenna 102, the plasma chemistry in the plasma chamber 106, and the type of operation occurring in the plasma chamber 106.

[0103] In a first embodiment, N magnets are placed in one or more of placement options 202-210. In a second embodiment, M magnets are placed in one or more of placement options 202-210 to achieve the same overall result, where M is greater than N and the strength of the magnets in the first embodiment is greater than the strength of the magnets in the second embodiment.

[0104] 1 and 2 are shown as symmetrical structures, with components arranged parallel to one another and with center points aligned linearly, however, it should be understood that asymmetric plasma processing systems may also utilize the magnets disclosed herein.

[0105] In embodiments where the magnet is an electromagnet or electro-permanent magnet, the electromagnet or electro-permanent magnet may be enabled during plasma processing and disabled when the plasma processing step is completed.

[0106] Figure 2B shows a top view (i.e., looking vertically down from the antenna 102 toward the plasma chamber 106) of a possible arrangement of magnets 242 on a plane corresponding to any of the arrangement options 202-210 of Figure 2A (i.e., not limited to the magnet positions shown in Figure 2B).

[0107] In FIG. 2B, the housing structure 104 is shown as having a cylindrical structure (ie, with a circular cross-section), although other geometric shapes for the housing structure 104 are also contemplated.

[0108] Magnet 242 may be positioned anywhere on the plane defined by any of placement options 202-210 (with the obvious caveat that two bodies cannot occupy the same space). For example, magnet 242 may be positioned within exemplary outline 244 of antenna 102, which is a structure having an open volume on the plane (i.e., not a solid cylinder). Magnet 242 may be positioned on the plane inside or outside housing structure 104.

[0109] 2B, embodiments are also contemplated in which the magnets are uniformly arranged in a particular pattern, such as, for example, symmetrically arranged or concentrically arranged about the center point of antenna 102. For example, the magnets may be arranged in a ring outline concentrically arranged with antenna 102 (e.g., having the same center point as antenna 102).

[0110] Magnets 242 or a subset of magnets may be arranged to have a particular polarity axis (e.g., the embodiments of FIGS. 3, 4, and 5). In embodiments, the polarity position and axis of each magnet 242 is configurable. For example, the position of each magnet 242 may be mechanically or electronically adjusted vertically or horizontally, for example, based on measurements of a sampled wafer or based on a feedback circuit that measures one or more characteristics of the plasma. As another example, the polarity axis of magnet 242 may be mechanically or electronically adjusted using methods similar to those used to adjust the vertical and horizontal positioning of magnet 242. In embodiments, magnets 242 are electromagnets or electro-permanent magnets. In such embodiments, instead of adjusting the position of magnets 242 vertically and horizontally, magnets 242 may be enabled in different planes or at different horizontal positions in the same plane, while other magnets may be disabled in the same plane (i.e., horizontal adjustment) or in different planes (i.e., vertical adjustment).

[0111] Thus, while in embodiments, particular vertical and horizontal positioning and associated polarity axes of magnet 242 may be desired, it should be understood that magnet 242 may be positioned (horizontally and vertically) in any position above the plasma generation region (i.e., away from plasma chamber 106 and toward antenna 102) with any variety in polarity axes.

[0112] FIG. 3 shows a top view (i.e., vertically, looking down from the antenna 102 into the plasma chamber 106) of an embodiment of an arrangement of magnets 300 that may be used in any of the arrangement options 202-210 as shown in FIG. 2A.

[0113] The magnets 302 are positioned in a plane of a ring-shaped configuration that is parallel to the plane of the dielectric plate 114. As shown, the magnets 302 are positioned along the ring such that the polar axis of each magnet 302 is perpendicular to the plasma (i.e., the polar axis is in the vertical plane) within the plasma chamber 106. The polarity of each magnet is also perpendicular to the contour of the ring shape.

[0114] In an embodiment, magnet 302 is a cylindrical magnet with axial polarity. In an embodiment, the axial polarity of the magnet can be reversed either manually, for example, in the case of a permanent magnet, or electrically, for example, by reversing the current in the case of an electromagnet.

[0115] Each magnet 302 is shown with a north pole further away from the plasma chamber 106 than its respective south pole. However, this configuration is non-limiting and for illustrative purposes only. For example, in one embodiment, the magnets 302 may be arranged in a configuration such that the south pole of each magnet 302 is further away from the plasma chamber 106 than the north pole of each magnet 302. As another example, in an embodiment, some magnets 302 are arranged such that their north poles are further away from the plasma chamber 106 than their south poles, while other magnets 302 on the same ring are arranged such that their south poles are further away from the plasma chamber 106 than their north poles. In some embodiments, these arrangements are symmetrical, while in other embodiments, the arrangements are asymmetrical.

[0116] FIG. 4 shows a top view (i.e., vertically, looking down from the antenna 102 into the plasma chamber 106) of an embodiment of an arrangement of magnets 400 that may be used in any of the arrangement options 202-210 as shown in FIG. 2A.

[0117] The magnets 402 are positioned in a plane of a ring-shaped configuration that is parallel to the plane of the dielectric plate 114. As shown, the magnets 402 are positioned along the ring such that the polar axis of each magnet 402 is parallel to the plasma in the plasma chamber 106 (i.e., the polar axis in a horizontal plane) and tangent to the ring contour.

[0118] Each magnet 402 is shown with a north pole that is further counterclockwise around the ring relative to its south pole. However, this configuration is non-limiting and for illustrative purposes only. For example, in one embodiment, each magnet 402 may be arranged in a configuration such that its south pole is further counterclockwise around the ring relative to its north pole. As another example, in an embodiment, some magnets 402 are arranged such that their respective north poles are further counterclockwise around the ring relative to their south poles, while other magnets 402 on the same ring are arranged such that their respective south poles are further counterclockwise around the ring relative to their north poles. In some embodiments, these arrangements are symmetrical, while in other embodiments, the arrangements are asymmetrical.

[0119] FIG. 5 shows a top view (i.e., vertically, looking down from the antenna 102 into the plasma chamber 106) of an embodiment of an arrangement of magnets 500 that may be used in any of the arrangement options 202-210 as shown in FIG. 2A.

[0120] The magnets 502 are positioned in the plane of the ring-shaped configuration in a plane parallel to the plane of the dielectric plate 114. As shown, the magnets 402 are positioned along the ring such that the polar axis of each magnet 402 is parallel to the plasma in the plasma chamber 106 (i.e., polar axis in a horizontal plane) and perpendicular to the ring contour.

[0121] Each magnet 502 is shown having a north pole and a south pole along a line connected through the center of the ring, with its respective north pole closer than its south pole along the line to the center of the ring. However, this configuration is non-limiting and for illustrative purposes only. For example, in one embodiment, the respective south pole of each magnet is closer than its north pole along the line to the center of the ring. As another example, in an embodiment, some magnets 502 are positioned such that their respective north poles are closer along the line to the center of the ring than their south poles, while other magnets 502 are positioned such that their respective south poles are closer along the line to the center of the ring than their north poles. In some embodiments, these arrangements are symmetrical, while in other embodiments, the arrangements are asymmetrical.

[0122] The dashed ring outlines shown in Figures 3, 4, and 5 may be positioned on any of the planes shown in Figure 2A. The ring may have a diameter larger than, smaller than, or substantially the same as, the antenna 102.

[0123] In one embodiment (not shown), the antenna 102 has arms that connect an inner ring to an outer ring in a manner similar to the spokes of a wagon wheel. In such an embodiment, a magnet is located in the gap between the arms, and thus in the same plane as the planar antenna, and between the inner and outer peripheries of the antenna 102. In some embodiments, the magnet is in the same plane as, below, or above the antenna 102.

[0124] 6 shows a top view (i.e., looking vertically, down from antenna 102 into plasma chamber 106) of an embodiment of a magnet 600 arrangement that may be used in any of the arrangement options 202-210 as shown in FIG. 2A. Magnets 602 and 604 correspond to one or more of the magnets as disclosed with respect to magnet 300 arrangement, magnet 400 arrangement, magnet 500 arrangement, or a combination thereof.

[0125] In the arrangement of magnets 600, a first set of magnets 602 is disposed on the outer periphery of antenna 102, and a second set of magnets 604 is disposed on the inner periphery of antenna 102. Magnets 602 and 604 in Figure 6 are shown aligned radially. The centers of the rings corresponding to first set of magnets 602 and second set of magnets 604 are the same as the center of antenna 102, which is, for example, doughnut-shaped.

[0126] It should be noted that the first set of magnets 602 and the second set of magnets 604 do not have to be in the same vertical plane as the antenna 102 or in the same plane as each other. For example, the first set of magnets 602 and the second set of magnets 604 may be positioned vertically above or below the antenna 102.

[0127] 7 shows a top view (i.e., looking vertically, down from antenna 102 into plasma chamber 106) of an embodiment of a magnet 700 arrangement that may be used in any of the arrangement options 202-210 as shown in FIG. 2A. Magnets 702 and 704 correspond to one or more of the magnets as disclosed with respect to magnet 300 arrangement, magnet 400 arrangement, magnet 500 arrangement, or a combination thereof.

[0128] In the arrangement of magnets 700, a first set of magnets 702 is disposed on the outer periphery of antenna 102, and a second set of magnets 704 is disposed on the inner periphery of antenna 102. The magnets 702 and 704 in Figure 7 are shown in a radially staggered arrangement. The centers of the rings corresponding to first set of magnets 702 and second set of magnets 704 are the same as the center of the donut-shaped antenna 102.

[0129] It should be noted that the first set of magnets 702 and the second set of magnets 704 do not have to be in the same vertical plane as the antenna 102, or even in the same plane as each other. For example, the first set of magnets 702 and the second set of magnets 704 may be positioned vertically above or below the antenna 102.

[0130] In an embodiment, a single ring-shaped permanent magnet with a solid, constant magnetic field may be envisioned. In one embodiment, the single ring-shaped permanent magnet may replace magnets 302, 402, 502, 602, 604, 702, or 706. In another embodiment, a single ring-shaped electromagnet or electro-permanent magnet may replace magnets 302, 402, 502, 602, 604, 702, or 706.

[0131] Instead of having multiple individual magnets arranged along a ring, embodiments contemplate a single ring-shaped electromagnet or electro-permanent magnet, in which the polarity of the ring-shaped electromagnet or electro-permanent magnet can be selectively changed, for example, by changing the winding(s) or reversing the current through the winding(s) to produce a differently shaped magnetic field or to reverse the magnetic field.

[0132] In embodiments, each magnet 302, 402, 502, 602, 604, 702, or 704 is a permanent magnet. In other embodiments, each magnet 302, 402, 502, 602, 604, 702, or 704 is an electromagnet or electro-permanent magnet. In such embodiments, the polarity of the electromagnet or electro-permanent magnet can be controlled, for example, by reversing or changing the current used to generate the magnetic effect.

[0133] In an embodiment, some magnets 302, 402, 502, 602, 604, 702, or 704 are permanent magnets and other magnets 302, 402, 502, 602, 604, 702, or 704 on the same ring are electromagnets or electro-permanent magnets.

[0134] In one embodiment, a single magnet 302, 402, or 502 is positioned vertically in the center of the antenna 102. Note that the single magnet 302, 402, or 502 does not have to be on the same vertical plane as the antenna 102. For example, the single magnet 302, 402, or 502 may be positioned vertically above or below the antenna 102.

[0135] The magnets in Figures 3-7 may be positioned at any location on the dashed ring. Furthermore, the magnets do not necessarily have to be positioned at every location along the dashed line. It should be noted that the magnet placement is not limited to those shown in Figures 3-7, and other configurations or combinations of embodiments are also contemplated.

[0136] Although each embodiment includes a particular polarity arrangement of the magnets, the polarity arrangement need not be uniform or limited to the arrangement shown. For example, the magnets may have the same polarity orientation, may have alternating polarity orientation, or may include a polarity orientation with or without a pattern along dashed lines.

[0137] In an embodiment, an electromagnet or electro-permanent magnet is a magnet with windings that effectively produces the same results as a permanent magnet.

[0138] In various embodiments, the magnets are illustrated as being positioned along a ring, however, the ring shape is non-limiting and other arrangements that allow for symmetry, such as octagonal, square, elliptical, etc. are also contemplated.

[0139] In an embodiment, the magnets are positioned equidistant from the feed or ground point of the antenna 102. In an embodiment, due to asymmetries in the field generated by the antenna 102, the magnets may be selectively positioned (not necessarily at the same distance from the outer or central point) to compensate for skew in the generated plasma.

[0140] In an embodiment, the magnets are positioned substantially on the ring contour, with some small misalignment relative to the ring (eg, 5% inward or outward).

[0141] The arrangement of magnets along the ring is not limited to those disclosed with reference only to Figures 3-7, and combinations of embodiments are contemplated. For example, in embodiments, several magnets on the same ring may be arranged as disclosed using two or more of the arrangement of magnets 300, the arrangement of magnets 400, the arrangement of magnets 500, or combinations thereof. Some magnets on a ring may have a vertical polar axis, while some magnets on the same ring may have a horizontal polar axis. As another example, some magnets on a ring may be arranged to have a radial axis relative to the ring, while other magnets on the same ring may be arranged to have an axial axis relative to the ring. Thus, any of the combinations disclosed above may be used as a configuration for arranging magnets.

[0142] Each configuration as disclosed above may have a different effect on the plasma in the plasma chamber 106. For example, one configuration may improve the radial density profile throughout the plasma. As another example, one configuration may improve the azimuthal uniformity of the plasma. In embodiments, the position of the magnet plane may be adjustable (e.g., mechanically or electrically) and may be shifted up or down based on the operation of the plasma processing system. In other embodiments, multiple electromagnets or electro-permanent magnets are positioned on different planes, and similar magnetic field shifts are contemplated by turning the electromagnets or electro-permanent magnets on and off on the different planes.

[0143] In one embodiment, the magnet is positioned (or enabled, in the case of an electromagnet or electro-permanent magnet) based on real-time measurements of changes in plasma stability, electron temperature, plasma density, plasma ignition stability, changes in the tunability of a matching network coupled to the antenna, or a combination thereof.

[0144] For example, the magnet configuration (eg, polarity direction, position, strength, etc.) may be mechanically or electronically altered to improve plasma stability, such as in low-pressure plasma conditions.

[0145] In one embodiment, measurements from a wafer between process steps may be used to adjust the magnetic field configuration of future wafers. In an embodiment, the analysis includes wafer thickness, feature height, trench depth, critical dimension (CD), uniformity, or a combination thereof.

[0146] In one embodiment, a feedback circuit is used to measure one or more parameters of the plasma processing system (i.e., plasma density, plasma impedance, etc.) and communicate the measurements to a controller circuit, which can manually or automatically adjust the magnet configuration based on the received measurements.

[0147] In one embodiment, the magnets are positioned (or enabled in the case of electromagnets or electro-permanent magnets) based on a predetermined configuration stored in a look-up table in a memory coupled to a controller that is used to adjust the configuration of the magnets.

[0148] For example, a first configuration of magnets known to improve plasma stability at a first pressure may be stored in memory, a second configuration of magnets known to improve plasma stability at a second pressure may be stored in memory, etc. Additional specific configurations may be stored in memory for other parameters, combinations of parameters, etc.

[0149] In an embodiment, the controller electronically adjusts, for example, the position, strength, polarity, and one or more magnets based on predetermined configurations stored in memory to improve one or more key conditions of a particular plasma processing operation.

[0150] 8 shows a block diagram of an embodiment of a processing system 800 that may be coupled to plasma processing system 100. As shown, processing system 800 includes a processor 802, a memory 804, an interface 806, an optional feedback circuit 808, and an optional measurement circuit 810, which may (or may not) be configured as shown. Processing system 800 may include additional components not shown, such as long-term storage (e.g., non-volatile memory, etc.), measurement devices, etc.

[0151] Processor 802 may be any component or collection of components adapted to perform computations or other processing-related tasks. Memory 804 may be any component or collection of components adapted to store programs or instructions for execution by processor 802. In one embodiment, memory 804 includes a non-transitory computer-readable medium.

[0152] Interface 806 may be any component or collection of components that allows processor 802 to communicate with other devices / components or users. For example, interface 806 may be adapted to communicate data, control, or management messages from processor 802 to structure or circuitry coupled to one or more magnets to adjust the configuration of the magnets based on instructions or configurations stored in memory 804.

[0153] As another example, interface 806 may be adapted to allow a user or device (eg, a personal computer (PC), etc.) to interact / communicate with processing system 800 .

[0154] Feedback circuit 808 receives measurements from measurement circuit 810 and, via processor 802, can be used to automatically or manually change the configuration of magnets in plasma processing system 100. Measurement circuit 810 can be used to measure, for example, plasma stability, pressure, ignition stability, density, etc.

[0155] 9 is a flowchart of an embodiment of a method 900 for adjusting the magnet configuration of the plasma processing system 100. In step 902, a plasma processing operation is set. The plasma processing operation corresponds to an operation such as etching, deposition, oxidation, sputtering, etc. The plasma processing operation sets, for example, pressure conditions, frequency, etc., for processing a wafer in the plasma processing system.

[0156] Optionally, in step 904, various parameters related to the plasma processing system are collected, for example, using measurement circuitry 810. For example, the measurement circuitry may be configured to collect plasma density, stability, ignition stability, pressure, etc.

[0157] In step 906, the plasma processing system 100 adjusts the magnet configuration using, for example, the processor 802. The processor 802 may adjust the magnet configuration based on the plasma processing operation, the collected measurements, or a combination thereof.

[0158] In an embodiment, the processor 802 may select a magnet configuration based on, for example, a lookup table stored in memory 804. The lookup table may be used to instruct or command the processor to reconfigure the magnets to achieve a particular value(s) of a parameter(s) associated with the plasma processing system. For example, the processor 802 may adjust the magnet configuration to achieve a particular plasma density or stability specified in the lookup table. In an embodiment, the processor 802 may communicate with a feedback circuit 808 and a measurement circuit 810 to further refine the magnet configuration.

[0159] Although described in detail, it should be understood that various changes, substitutions, and alterations may be made therein without departing from the spirit and scope of the present disclosure as defined by the appended claims. Like elements in the various figures are designated with like reference numerals. Moreover, the scope of the present disclosure is not intended to be limited to the particular embodiments described herein; those skilled in the art will readily appreciate from this disclosure that any now-existing or later-developed process, machine, manufacture, composition of matter, means, method, or step can perform substantially the same function or achieve substantially the same result as the corresponding embodiment described herein. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

[0160] The specification and drawings, therefore, should be considered merely as illustrative of the present disclosure as defined by the appended claims, and are intended to cover any and all modifications, variations, combinations, or equivalents that fall within the scope of the present disclosure. For example, it should be understood that the physical placement and arrangement of components in various embodiments of the plasma processing system or resonant structure is non-limiting. For example, while the resonant structure is located between the RF source and the plasma processing system in various illustrations, this placement is non-limiting, and these components may be located near, above, or below other components while remaining within the scope of the present disclosure.

Claims

1. 1. A plasma processing system comprising: a plasma chamber; a planar antenna configured to generate a plasma in the plasma chamber; a dielectric plate disposed between the plasma chamber and the planar antenna; a plurality of magnets arranged vertically above an outer surface of the dielectric plate facing the plasma chamber; A plasma processing system comprising:

2. 10. The plasma processing system of claim 1, wherein one or more of the plurality of magnets is a permanent magnet, an electromagnet, an electro-permanent magnet (EPM), or a combination thereof.

3. 10. The plasma processing system of claim 1, wherein one or more magnets of the plurality of magnets have a polar axis perpendicular to the dielectric plate, a polar axis parallel to the dielectric plate, or a combination thereof.

4. 10. The plasma processing system of claim 1, wherein one or more magnets of the plurality of magnets are arranged along a ring parallel to the planar antenna, and wherein one or more magnets of the plurality of magnets have a polar axis perpendicular to the ring, a polar axis tangent to the ring, or a combination thereof.

5. 10. The plasma processing system of claim 1, further comprising a housing structure, wherein the antenna is disposed within the housing structure, and the dielectric plate is positioned between the housing structure and the plasma chamber.

6. The plasma processing system of claim 5 , wherein one or more magnets of said plurality of magnets are disposed external to said housing structure.

7. 2. The plasma processing system of claim 1, wherein one or more magnets of said plurality of magnets are arranged in a plane parallel to said planar antenna.

8. 8. The plasma processing system of claim 7, wherein the plane is vertically adjustable from the outer surface of the dielectric plate facing the plasma chamber to a second plane, and the planar antenna is disposed between the second plane and the dielectric plate.

9. 1. A plasma processing system comprising: a plasma chamber having a top surface and a bottom surface opposite the top surface; an antenna configured to generate a plasma within a plasma generation region within the plasma chamber; a dielectric plate disposed between the plasma chamber and the antenna, wherein a top surface of the plasma generation region corresponds to a bottom surface of the dielectric plate adjacent to the top surface of the plasma chamber; a plurality of magnets arranged vertically above the top surface of the plasma generating region in a direction from a bottom surface of the plasma chamber toward the top surface of the plasma chamber, wherein the position or polarity axis of one or more of the magnets is configurable; A plasma processing system comprising:

10. 10. The plasma processing system of claim 9, wherein one or more of the plurality of magnets is a permanent magnet, an electromagnet, an electro-permanent magnet (EPM), or a combination thereof.

11. 10. The plasma processing system of claim 9, wherein one or more magnets of the plurality of magnets have a polar axis perpendicular to the plasma, a polar axis parallel to the plasma, or a combination thereof.

12. 10. The plasma processing system of claim 9, wherein the antenna is donut-shaped, a first subset of magnets disposed on a first plane around an outer periphery of the antenna and parallel to the antenna, and a second subset of magnets disposed on a second plane within an inner periphery of the antenna and parallel to the antenna.

13. 13. The plasma processing system of claim 12, wherein the first plane and the second plane are the same plane.

14. 13. The plasma processing system of claim 12, wherein the magnets of the first subset of magnets are symmetrically arranged around the outer periphery of the antenna and the magnets of the second subset of magnets are symmetrically arranged within the inner periphery of the antenna.

15. 10. The plasma processing system of claim 9, wherein determining the magnet placement is based on changes in the plasma density, stability, pressure, ignition stability, changes in the tunability of a matching network coupled to the antenna, or combinations thereof.

16. 10. The plasma processing system of claim 9, wherein the plasma is a low-pressure plasma corresponding to a pressure of 10 milliTorr (mTorr) or less.

17. 1. A method of operating a plasma processing system, comprising: configuring a plasma processing operation for the plasma processing system, the plasma processing system comprising: a plasma chamber; an antenna used to generate a plasma in the plasma chamber; a dielectric plate disposed between the plasma chamber and the antenna; a plurality of magnets arranged vertically above an outer surface of the dielectric plate facing the plasma chamber; setting a plasma processing operation comprising: measuring one or more parameters associated with the plasma processing system; adjusting the placement of one or more magnets based on the plasma processing operation and the one or more parameters; A method comprising:

18. 20. The method of claim 17, wherein the one or more parameters comprise one or more of plasma stability, electron temperature, plasma ignition stability, plasma density, or tunability of a matching network coupled to the antenna.

19. 18. The method of claim 17, wherein one or more magnets of the plurality of magnets are stationary electromagnets, and adjusting the arrangement of one or more magnets comprises enabling, disabling, adjusting, or reversing current in one or more of the stationary electromagnets.

20. 18. The method of claim 17, wherein one or more magnets of the plurality of magnets are permanent magnets disposed on a mechanical structure parallel to the outer surface of the dielectric plate, and wherein adjusting the arrangement of one or more magnets comprises vertically shifting the mechanical structure between a first plane and a second plane, the first plane being the outer surface of the dielectric plate and the second plane being a plane perpendicular above the antenna.

21. 20. The method of claim 17, wherein the adjusting comprises determining a magnet configuration using a lookup table, the lookup table having a plurality of configurations for the magnet based on the plasma processing operation and the one or more parameters.

Images