Plasma processing chamber

Abstract

Specific embodiments of this disclosure include apparatus and methods for plasma processing of a substrate. Some embodiments relate to a plasma processing chamber. The plasma processing chamber generally includes: a planar coil region comprising a plurality of planar coils; a first power supply circuit coupled to at least two of the plurality of planar coils; a concentric coil region at least partially surrounding the planar coil region; and a second power supply circuit coupled to at least two of the concentric coils. The first power supply circuit may be configured to bias at least two of the planar coils to influence plasma in a central region of the plasma processing chamber, and the second power supply circuit may be configured to bias at least two of the planar coils to influence plasma in an outer region.

Description

Plasma Uniformity Control System and Method Specific embodiments of the present disclosure generally relate to systems for manufacturing semiconductor devices. More specifically, specific embodiments of the present disclosure relate to a plasma processing system for plasma processing a substrate and a method of using the same. Reliably forming high aspect ratio features is one of the key technical challenges for next-generation semiconductor devices. One method of forming high aspect ratio features uses a plasma-assisted etching process to bombard a material formed on a substrate surface through an opening formed in a patterned mask layer formed on the substrate surface. As the technology node advances to 2nm, manufacturing smaller features with larger aspect ratios requires atomic-level precision in plasma processing. For etching processes where plasma ions play a major role, ion energy control has been a challenge in the semiconductor equipment industry to develop reliable and repeatable device formation processes. In a typical plasma-assisted etching process, a substrate is located on a substrate support in a processing chamber, and a plasma is formed above the substrate by using a radio frequency (RF) generator coupled to an electrode, the electrode is disposed on or within the plasma processing chamber, and ions are accelerated from the plasma through the plasma sheath towards the substrate. In addition, in addition to the RF generator for initiating and maintaining the plasma in the processing chamber, the RF substrate biasing method that requires the use of a separate RF bias source cannot ideally control the plasma sheath characteristics to obtain an ideal effect, which would allow for the formation of these smaller device feature sizes. However, due to variations in the electrical characteristics and / or spatial arrangement of the processing components disposed within the processing region of the plasma processing chamber, non-uniformities in plasma density and / or the shape of the plasma sheath may occur. A common plasma density variation is generated within a conventional inductively coupled plasma source, the conventional inductively coupled plasma source including a coil located above the processing region of the plasma chamber, because the coil is axisymmetric and thus has a magnetic field zero point located at the central axis of the coil. The variation in the plasma will result in undesired processing results in the etched features formed on the substrate surface. Excessive variations in plasma non-uniformity will have an adverse effect on the processing results and reduce device yield. Such non-uniformities are typically particularly evident near and / or between the center and the edge of the substrate. Therefore, there is a need in the art to control and / or minimize the adverse effects of plasma non-uniformity inside the plasma chamber. There is also a need for a system, device, and method to solve the above problems. To achieve the foregoing and related purposes, one or more aspects include features that are fully described hereinafter and particularly pointed out in the claims. The following description and the drawings detail certain illustrative features of one or more aspects. However, these features merely indicate some of the various ways in which the principles of the various aspects may be employed. Specific embodiments provided herein generally include an apparatus, a plasma processing system, and a method for generating a waveform for plasma processing a substrate in a processing chamber. Specific embodiments of the present disclosure provide a plasma processing chamber. The plasma processing chamber generally includes a planar coil region that includes a plurality of planar coils, where each of the plurality of planar coils includes a coil disposed between a first end and a second end, and the coil has a first portion aligned parallel to a plane, and a first power circuit coupled to at least two of the plurality of planar coils. The first power circuit can be configured to bias at least two of the plurality of planar coils to affect the plasma formed in a central region of the plasma processing chamber. The plasma processing chamber generally further includes a concentric coil region that includes a first concentric coil and a second concentric coil, where at least a portion of the planar coil region is surrounded by the first concentric coil and the second concentric coil, the first concentric coil includes a first coil having a first diameter measured in a direction parallel to a first plane, the second concentric coil includes a second coil having a second diameter measured in a direction parallel to the first plane, and the first diameter is less than the second diameter. The plasma processing chamber generally further includes a second power circuit coupled to at least two of the plurality of concentric coils, where the second power circuit is configured to bias the first concentric coil and the second concentric coil to change the characteristics of the plasma formed in an outer region of the plasma processing chamber. Specific embodiments of the present disclosure provide a method of processing a substrate. The method of processing a substrate generally includes performing a processing sequence on a substrate disposed in a processing region of a plasma processing chamber. The processing sequence generally includes: biasing at least two of the plurality of planar coils disposed in the planar coil region by using a first power circuit, and each of the plurality of planar coils includes a coil disposed between a first end and a second end, and the coil has a first portion aligned parallel to a first plane, where the step of biasing at least two of the plurality of planar coils includes the steps of: transmitting a first bias signal to the coil of a first planar coil of the plurality of planar coils; and transmitting a second bias signal to the coil of a second planar coil of the plurality of planar coils, and the step of biasing at least two of the plurality of planar coils is configured to change the characteristics of the plasma formed in a central region of the plasma processing chamber. The processing sequence also generally includes: biasing at least two of the plurality of planar coils disposed in the planar coil region by using a first power circuit, where the step of biasing at least two of the plurality of planar coils includes the steps of: transmitting a third bias signal to the coil of a third planar coil of the plurality of planar coils; and transmitting a fourth bias signal to the coil of a fourth planar coil of the plurality of planar coils, and the step of biasing at least two of the plurality of planar coils is configured to change the characteristics of the plasma formed in a central region of the plasma processing chamber. In the following description, details are set forth by way of example in order to facilitate understanding of the disclosed subject matter. However, it will be apparent to those of ordinary skill in the art that the disclosed implementations are exemplary and do not exhaust all possible implementations. Accordingly, it is to be understood that reference to the described examples is not intended to limit the scope of the disclosure. Any changes and further modifications to the described apparatus, instrument, method, and any further applications of the principles of the disclosure are fully contemplated, as would normally be thought of by a person skilled in the art to which the disclosure pertains. Specifically, it is fully contemplated that features, components, and / or steps described in connection with one implementation may be combined with features, components, and / or steps described in connection with other implementations of the disclosure. As used herein, the term "about" may refer to a variation of + / - 10% from a nominal value. It should be understood that such variations may be included in any value provided herein. Specific embodiments of the disclosure generally relate to systems that may be used in a semiconductor device manufacturing process sequence. More specifically, the specific embodiments provided herein generally include apparatuses and methods for controlling and synchronizing the delivery of magnetic fields generated from a field generation system disposed within a plasma processing chamber. The apparatuses and methods disclosed herein may be used to at least minimize or eliminate the effects of plasma non-uniformity on a substrate. The plasma processing methods and apparatuses described herein are configured to improve control over various characteristics of the generated plasma and to control the ion energy distribution (IED) of plasma-generated ions that interact with the surface of the substrate during plasma processing. The ability to synchronize and control the magnetic fields generated by the field generation system during processing allows for improved control over one or more characteristics of the generated plasma, such as plasma uniformity, plasma density, IED, electron energy distribution (EED), or other useful parameters. The improved plasma control is used to improve the plasma processing results performed in the plasma processing chamber, for example, to form desired high aspect ratio features in the surface of the substrate through a reactive ion etching process. Accordingly, a higher precision of plasma processing may be achieved, which is described in more detail herein. Specific embodiments of the disclosure provide an apparatus and method for controlling fields generated by one or more coils in a field generation system of a plasma processing system to achieve higher precision during plasma processing. Example Plasma Processing System FIG. 1 is a simplified schematic diagram of a plasma processing system 100, which can be configured to implement the methods described herein. In FIG. 1 and subsequent figures of the present disclosure, CL represents the center line of the plasma processing system 100, R− represents the negative radial direction, and R+ represents the positive radial direction. The plasma processing system 100 is adapted to process a substrate 13 disposed on a substrate support assembly 140 by generating a plasma 11 within a processing volume 134 of a plasma processing chamber 150. The plasma 11 can include multiple regions of the formed plasma. In some embodiments, the formed plasma 11 can include a central region 160, which can be surrounded by an outer region 170. The plasma processing system 100 is configured to form an inductively coupled plasma (ICP), wherein the processing chamber 150 includes a field generation system 101 disposed above a portion of the processing volume 134 such that at least a portion of the field generation system 101 faces a bias electrode 114. The bias electrode 114 is disposed within the substrate support assembly 140, and the substrate support assembly 140 is disposed within the processing volume 134. The bias electrode 114 is also often referred to herein as the substrate support electrode and can be coupled to a generator 110. In some embodiments, the field generation system 101 includes one or more planar coils (e.g., radial coils 102F, 102G) in a planar coil region 112. The field generation system 101 also includes one or more concentric coils (e.g., concentric coils 102A, 102B, 102C, 102D) in a concentric coil region 118. The one or more concentric coils are circular and can form a loop around the one or more radial coils, as shown in FIG. 3. At least one of the one or more concentric coils can be a solenoid-type coil. The one or more planar coils can be disposed above the plasma 11 in the central region 160, and the one or more concentric coils can be disposed above the plasma 11 in the outer region 170. The planar coils and concentric coils can be coils including multiple coil layers, as shown in FIG. 2. Although four concentric coils and two planar coils are shown in the example of FIG. 1, any number of concentric coils and planar coils can be used. In some embodiments, the field generation system 101 can be coupled to a power transmission system 103. The power transmission system 103 can include power circuit components having a separate driver for each concentric coil and planar coil, each driver being configured to bias (e.g., drive) the concentric coils and planar coils. Alternatively, the power transmission system 103 can include power circuit components including a first power circuit and a second power circuit. The power circuit components can include fewer drivers than the concentric and planar coils such that one driver can be configured to bias multiple coils. The processing chamber 150 generally includes a chamber body 130, the chamber body 130 includes one or more sidewalls 131 and a chamber base 132, and the chamber base 132 and the chamber lid 133 together define a processing volume 134. The one or more sidewalls 131 and the chamber base 132 generally include materials, the size and shape of the materials being designed to form the structural support of the components of the processing chamber 150, and the materials being configured to withstand the pressure and increased energy applied to the materials while generating a processing plasma 11 in the vacuum environment maintained in the processing volume 134 of the processing chamber 150 during processing. In one example, the one or more sidewalls 131 and the chamber base 132 are formed of metal, such as aluminum, aluminum alloy, or stainless steel alloy. In some embodiments, the field generation system 101 is coupled to or disposed on the showerhead 180. The showerhead 180 includes a gas boosting region 182 and a plurality of openings 184. The showerhead 180 is disposed through the chamber lid 133 and is configured to deliver one or more processing gases from a processing gas source 119 fluidly connected thereto through the openings 184 to the processing volume 134. The processing gases provided by the processing gas source 119 will include reactive etchant gases and inert gases. The pressure within the processing chamber 150 can be controlled by using a vacuum pump (not shown) and the amount of gas flow provided from the processing gas source 119. The substrate 13 is loaded into and removed from the processing volume 134 through an opening (not shown) in one of the one or more sidewalls 131, and the opening is sealed by a slit valve (not shown) during the plasma processing of the substrate 13. The showerhead 180 is composed of a material having a low magnetic permeability such that the planar and concentric coils in the bias field generation system 101 generate a magnetic field that can affect the plasma 11 in the central region 160 and the outer region 170 of the processing volume 134. For example, the showerhead 180 can be a metal plate and can include aluminum, quartz, or other materials having a low magnetic permeability. In some embodiments, the generator 110 can be a pulsed voltage (PV) waveform generator that is electrically coupled to the bias electrode 114 through an RF filter 111, and the RF filter 111 is configured to prevent RF signals from reaching the generator 110 during processing. The generator 110 can also be an RF source generator that is electrically coupled to the bias electrode 114 through the RF filter 111 and can transmit an RF signal configured to ignite and sustain a plasma (e.g., plasma 11). The substrate support assembly 140 may include a substrate support 105 (e.g., an ESC substrate support) and one or more bias electrodes coupled to a generator 110. In some embodiments, the substrate support assembly 140 may further include a support structure 106 that includes a support base for supporting the substrate support 105, an insulating plate (not shown), and a ground plate (not shown) coupled to the chamber base 132. The support base is electrically isolated from the chamber base 132 by the insulating plate, and the ground plate is interposed between the insulating plate and the chamber base 132. An isolation ring 141 containing a dielectric is typically positioned around the substrate support 105, the insulating plate, and the ground plate. The substrate support 105 is thermally coupled to and disposed on the support base, and the support base is configured to adjust the temperature of the substrate support 105 during processing. Typically, the substrate support 105 is formed of a dielectric material, such as a bulk sintered ceramic material, such as a corrosion-resistant metal oxide or metal nitride material. In embodiments herein, the substrate support assembly 140 further includes a bias electrode 114 embedded in its dielectric material. In one configuration, the bias electrode 114 is an adsorption rod for fixing (i.e., adsorbing) the substrate 13 to the substrate support surface of the substrate support assembly 140 and for biasing the substrate 13 relative to the processing plasma 11 using one or more of the pulsed voltage biasing schemes described herein. Typically, the bias electrode 114 is formed of one or more conductive components, such as one or more metal meshes, foils, plates, or combinations thereof. In some embodiments, the bias electrode 114 is also electrically coupled to an adsorption network that provides an adsorption voltage to the bias electrode 114, such as a static DC voltage between about -5000V and about 5000V. The system controller 126, also referred to herein as a process chamber controller, includes a central processing unit (CPU) 127, a memory 128, and support circuitry 129. The system controller 126 is used to control the processing sequence and method for processing the substrate 13, including the substrate processing methods described herein. The CPU 127 is a general-purpose computer processor configured for an industrial environment to control the processing chamber and its associated sub-processors. The memory 128 described herein is generally non-volatile memory and may include random access memory, read-only memory, floppy disk drives, or hard disk drives, or other suitable forms of local or remote digital storage. The support circuitry 129 is coupled to the CPU 127 in a conventional manner and may include cache memory, clock circuitry, input / output subsystems, power supplies, and the like, and combinations thereof. Software instructions (software programs) and data can be encoded and stored in the memory 128 to direct the processors within the CPU 127. The software programs (or computer instructions) readable by the CPU 127 in the system controller 126 determine which tasks can be performed by the components in the processing system 100. Generally, the software programs readable by the CPU 127 in the system controller 126 include code that, when executed by the CPU 127, performs tasks related to the plasma processing methods described herein. The programs may include instructions for controlling the various hardware and electronic components within the processing chamber 150 and the processing system 100 to perform various processing tasks and the various processing sequences for implementing the methods described herein. In one or more of the specific embodiments disclosed herein, the processing chamber 150 includes a sensor assembly (not shown) that is positioned to measure the characteristics of the PV waveform generated at the output of the source generator 110 and / or the RF waveform generated by the output of the power delivery system 103. The sensor assembly may include one or more electrical components configured to measure one or more electrical characteristics of the asymmetric voltage waveform provided by the source generator 110, such as voltage, current, and offset / phase, and to send the one or more electrical characteristic data to the system controller 126. The electrical characteristic data received by the system controller 126 from the source generator 110 can be used together to synchronize the delivery of other PV waveforms generated by the generator 110 and the power delivery system 103, as discussed further below. The system controller 126 and the support circuitry are configured to control and / or adjust the voltage waveform generated by the source generator 110. The source generator 110, the system controller 126, and the support circuitry are capable of adjusting a plurality of electrical parameters for changing one or more voltage waveform characteristics, such as the frequency, waveform shape, and applied voltage on-time during the pulse period of the provided asymmetric voltage waveform. Although the disclosure provided herein mainly discusses using the processing system 100 to perform plasma-assisted etching processes, such as reactive ion etching (RIE) plasma processing techniques, this configuration is not intended to limit the scope of the disclosure provided herein. It should be noted that the specific embodiments described herein can also be used with processing systems configured to be used in other plasma-assisted processes, such as plasma-enhanced deposition processes, such as plasma-enhanced chemical vapor deposition (PECVD) processes, plasma-enhanced physical vapor deposition (PEPVD) processes, plasma-enhanced atomic layer deposition (PEALD) processes, plasma treatment processes, or plasma-based ion implantation processes (such as plasma doping (PLAD) processes). Example field generation system FIG. 2 is a schematic side cross-sectional view of an example field generation system 101. As described above, the field generation system 101 includes a planar coil region 112 and a concentric coil region 118. In some specific embodiments, the field generation system 101 may include a plurality of coolant channels 116 disposed above the planar coil region 112 and the concentric coil region 118, and the coolant channels 116 are configured to cool the coils in the planar coil region 112 and the concentric coil region 118. The coolant channels 116 may be formed in a plate 117, and the plate 117 includes a high magnetic permeability material, such as an iron-containing material, a cobalt-containing material, steel, ferrite, or other similar materials. The planar coil region 112 may include a plurality of planar coils (e.g., radial coils 102F-102K (FIG. 3)), and the concentric coil region 118 may include one or more concentric coils (e.g., concentric coils 102A, 102B, 102C, 102D, 102E). One or more of the concentric coils in the concentric coil region 118 may each include a coil 202A formed as a plurality of coil layers (e.g., the multi-layer concentric coil 202 shown in FIG. 2), and each of the radial coils 102F-102K within the plurality of planar coils 204 may include a coil 204A, and the coil 204A is formed in a planar coil pattern stacked into a plurality of planar coil layers (e.g., the multi-layer planar coil 204 shown in FIG. 2). Generally, as shown in FIGS. 2-5 and 9-12, the planar coil region 112 will include a plurality of radial coils, and each radial coil includes a coil 204A, and the coil 204A is wound along a direction aligned parallel to a first plane, such as the XY plane. In some specific embodiments, as shown in FIG. 2, each radial coil includes a plurality of coil layers (e.g., the seven coil layers shown), and each coil layer includes a coil 204A aligned parallel to the first plane. The number of layers used in each of the coil regions 112, 118 in the field generation system 101 can be adjusted to generate a desired magnetic field, which can include radial and azimuthal field components. As described above, one or more concentric coils are circular and can form a ring around one or more radial coils, as shown in FIG. 3. Although five concentric coils and two planar coils are shown in the example of FIG. 2, any number of concentric coils and planar coils can be used. FIG. 3 is a schematic bottom view of the field generation system 101 shown in FIGS. 1 and 2. As described above, the field generation system 101 includes a planar coil region 112 and a concentric coil region 118. In the example of FIG. 3, the planar coil region 112 includes six planar coils (e.g., radial coils 102F, 102G, 102H, 102I, 102J, 102K), and the concentric coil region 118 can include five concentric coils (e.g., concentric coils 102A, 102B, 102C, 102D, 102E). The planar coils in the planar coil region 112 can be radially patterned coils. As described above with reference to FIG. 2, each of the concentric coils can include a coil wound to form multiple layers of coils 202A, and the planar coils can also include multiple layers of coils 204A. Although five concentric coils and six planar coils are shown in the example of FIG. 3, any number of concentric coils and planar coils can be used. For purposes of schematic representation and ease of illustration, the coils shown within the concentric coils 102A-102F are shown as being wound such that they have a planar orientation (e.g., the XY plane). However, as noted above and below, it is desirable for the concentric coils 102A-102E to be wound such that the coils have a central axis CL (e.g., the Z direction) that is primarily and substantially aligned in the vertical direction. In some embodiments, the concentric coil region 118 has an inner radius R I and an outer radius R O . The inner radius R I of the concentric coil region 118 is defined by the inner radius of the innermost concentric coil (e.g., concentric coil 102E in FIG. 3), and the outer radius R O is defined by the outer radius of the outermost concentric coil (e.g., concentric coil 102A in FIG. 3). In some embodiments, the radial coils within the planar coil region 112 are disposed within the region defined by the inner radius R I of the concentric coil region 118. The inner radius R IThe size can be between about 40 millimeters (mm) and about 100 mm. In one example, the inner radius R of the concentric coil region 118 I is about 50 mm, while the outer radius R of the concentric coil region 118 O is equal to or greater than the radius of the outer edge of the substrate 13, such that, for example, it is greater than or equal to 300 mm or 450 mm. In some specific embodiments, the outer radius R of the concentric coil region 118 O can be less than the radius of the outer edge of the substrate 13, for example, less than 300 mm. In some specific embodiments, the sizes of the planar coil region 112 and the concentric coil region 118 are designed such that the field generation system 101 includes a planar coil region ratio between about 0.1 and about 0.4 (i.e., inner radius R I / outer radius R O ), for example, between about 0.1 and about 0.35. In some specific embodiments, each coil in the coil region of the concentric coil region 118 can be coupled to a source driver (e.g., source drivers 302, 304, 306, 308, 310), which are included in the power circuit components of the power transmission system 103. Each source driver can be configured to selectively bias adjacent concentric coils in the same or opposite directions (e.g., positive and negative directions), as shown in FIGS. 9 and 10. Example of the planar coil region FIG. 4 is a schematic bottom view of the planar coil region 112 of the field generation system 101. In the example of FIG. 4, the planar coil region 112 includes six planar coils (e.g., radial coils 102F, 102G, 102H, 102I, 102J, 102K). As shown in FIG. 4, adjacent coils in the planar coil region 112 can be wound in the same direction, but are biased in opposite directions by the drivers of the source drivers 404 - 412, such that adjacent radial coils generate magnetic fields with opposite orientations when biased by the source drivers 404 - 412. Alternatively, adjacent coils in the planar coil region 112 can be wound in opposite ways, such that adjacent radial coils generate magnetic fields with opposite orientations when biased by the drivers 404 - 412. In one example, the first coil is wound in a clockwise direction, and the adjacent coil (e.g., the second coil) is wound in a counterclockwise direction, such that adjacent positioned coils generate magnetic fields with opposite orientations when energized. In some specific embodiments, each coil in the planar coil region 112 is coupled to a source driver, such as source drivers 402, 404, 406, 408, 410, 412, which are included in power circuit components arranged within the power transmission system 103. Each source driver can be configured to bias adjacent planar coils in opposite directions (e.g., a positive direction and a negative direction), as shown in FIGS. 9 and 10. In some specific embodiments, the coils in the planar coil region 112 can utilize other winding configurations. For example, adjacent coil pairs in the planar coil region 112 can be wound in the same direction, such that each coil in the adjacent coil pair is wound in the same manner, and adjacent coil pairs are wound in opposite manners (e.g., the first coil pair is wound in a clockwise direction, while the adjacent coil pair is wound in a counterclockwise direction). In another example, the coils in the planar coil region 112 can be wound such that adjacent coils in the planar coil region 112 are not coupled together, and each coil is wound independently of any other coil in the planar coil region 112. FIG. 5 is a schematic bottom view of an exemplary planar coil region 112 of the field generation system 101. In the example of FIG. 5, the planar coil region 112 includes six planar coils (e.g., radial coils 102F, 102G, 102H, 102I, 102J, 102K) wound similarly (e.g., wound in a counterclockwise direction). Although six planar coils are shown in the example of FIG. 5, any number of planar coils can be used. In some specific embodiments, two coils in the planar coil region 112 can be coupled to a single source driver (e.g., source drivers 502, 504, 506) included in the power circuit components of the power transmission system 103. For example, in FIG. 5, each driver is coupled to two coils in the planar coil region 112. Exemplary Power Transmission System FIG. 6 is a schematic diagram of an example of a power transmission circuit of the power transmission system 103 of the plasma processing system 100. The power transmission system 103 can include power circuit components. The power circuit components can include a first power circuit associated with the planar coil region 112 and a second power circuit associated with the concentric coil region 118. The second power supply circuit may include a plurality of drivers (e.g., source drivers 302, 304, 306, 308, 310), each source driver being configured to bias one or more concentric coils (e.g., concentric coils 102A, 102B, 102C, 102D, 102E) in opposite directions (e.g., a positive direction and a negative direction). In other words, biasing adjacent concentric coils in opposite directions may involve reversing the direction of the current flowing through the coils as needed. Each source driver may include a power supply (e.g., power supplies P1, P2, P3, P4, P5) coupled to switches (e.g., switches S1, S2, S3, S4, S5). These switches may be double-throw switches or double-pulse switches, as exemplified in FIG. 6. In the positions shown in the example of FIG. 6, source drivers 302, 306, and 310 are configured to bias concentric coils 102A, 102C, and 102E in the concentric coil region 118 in the positive direction, while source drivers 304 and 308 are configured to bias concentric coils 102B and 102D in the concentric coil region 118 in the negative direction. When switches S1, S3, and S5 are flipped from the positions shown in FIG. 6, the source drivers are configured to bias the coils in the concentric coil region 118 in the negative direction, and when switches S2 and S4 are flipped from the positions shown in FIG. 6, the source drivers are configured to bias the coils in the concentric coil region 118 in the positive direction. In other words, flipping the switches of the drivers causes the current to flow in the opposite direction. The source drivers coupled to the concentric coils in the concentric coil region 118 are configured to bias adjacent concentric coils in opposite directions. Source drivers similar to the source drivers shown in FIG. 6 may also be used in a similar manner to bias the coils in the planar coil region 112. For example, the first power supply circuit coupled to the planar coils in the planar coil region 112 may also include a plurality of drivers (e.g., source drivers 302, 304, 306, 308, 310), each source driver being configured to bias one or more planar coils (e.g., radial coils 102F, 102G, 102H, 102I, 102J, 102K) in opposite directions (e.g., a positive direction and a negative direction). In some embodiments, the planar coil in the planar coil region 112 and the concentric coil in the concentric coil region 118 can be biased (e.g., driven) to achieve greater uniformity between the plasma 11 in the central region 160 and the outer region 170, helping to at least minimize or eliminate the impact of plasma non-uniformity on the substrate 13. The planar coil and the concentric coil can be biased in various ways to achieve preferred plasma uniformity, plasma density, and tilt control of the generated plasma 11. One or more source drivers coupled to the planar coil in the planar coil region 112 can be configured to bias (e.g., drive) the planar coil in the planar coil region 112 to affect the plasma 11 in the central region 160 of the plasma processing chamber 150, by changing the absolute value of the current applied to the planar coil compared to the absolute value of the current in the concentric coil in the concentric coil region 118 to change the radial flux 150 in the central region 160 of the plasma processing chamber 150, as further discussed below. Changing the radial flux in the central region 160 changes the magnetic field and plasma density in the central region 160. One or more source drivers coupled to the planar coil in the planar coil region 118 can be configured to drive the planar coil in the planar coil region 112 at a low frequency. For example, the driver can apply an AC signal to the radial coil in the planar coil region 112 at a frequency of about 10 Hertz (Hz) or less (e.g., between 1 Hertz (Hz) and 2 Hertz (Hz)). In some embodiments, one or more source drivers coupled to the concentric coil in the concentric coil region 118 can be configured to bias (e.g., drive) the concentric coil in the concentric coil region 118 to affect the plasma 11 in the outer region 170 of the plasma processing chamber 150, by changing the absolute value of the current applied to the concentric coil compared to the absolute value of the current in the planar coil in the planar coil region 112 to change the radial flux in the outer region 170 of the plasma processing chamber 150. Changing the radial flux in the outer region 170 changes the magnetic field and plasma density in the outer region 170. The source driver coupled to the concentric coil in the concentric coil region 118 can be configured to drive the coil in the concentric coil region 118 using continuous direct current (DC). For example, the source driver can provide continuous direct current to drive the coil in the concentric coil region 118. However, in some embodiments, it may be desirable for the driver to apply an AC signal to the concentric coil in the concentric coil region 118 at a frequency of about 10 Hertz (Hz) or less (e.g., between 1 Hertz (Hz) and 2 Hertz (Hz)). FIG. 7 is a schematic diagram of an example of a power supply component of the power transmission system 103 of the plasma processing system 100. The power transmission system 103 may include a power circuit component having a first power circuit. The first power circuit may include a source driver (e.g., source driver 502) configured to bias one or more planar coils (e.g., one or more radial coils 102F, 102G) in opposite directions. In other words, biasing adjacent concentric coils in opposite directions may involve reversing the direction of the current flowing through the coils as needed. In the example of FIG. 7, the source driver is configured to bias two planar coils in the planar coil region 112 simultaneously. In other words, three source drivers may be used to bias six planar coils in the planar coil region 112. A source driver similar to the driver shown in FIG. 7 may also be used in a similar manner to bias multiple coils in the concentric coil region 118. For example, a source driver (e.g., source driver 502) may be configured to bias one or more concentric coils (e.g., one or more concentric coils 102A, 102B, 102C, 102D, 102E) in opposite directions. The source driver 502 may include a power supply (e.g., power supply P1) coupled to two switches (e.g., switches S1, S2). These switches may be double-throw switches or double-pulse switches, as shown in the example of FIG. 7. In the position shown in the example of FIG. 7, the source driver 502 is configured to bias the radial coil 102F in the planar coil region 112 in the positive direction and bias the radial coil 102G in the planar coil region 112 in the negative direction. When switches S1 and S2 are flipped from the position shown in FIG. 7, the source driver 502 will be configured to bias the radial coil 102F in the planar coil region 112 in the negative direction and bias the radial coil 102G in the planar coil region 112 in the positive direction. In other words, flipping the switches of the source driver 502 causes the current to flow in the opposite direction in the coils. As described above, the coils may be biased (e.g., driven) to achieve greater uniformity between the plasma 11 in the central region 160 and the outer region 170, helping to at least minimize or eliminate the effects of plasma non-uniformity on the substrate 13. Example of a processing sequence FIG. 8 is a flowchart depicting a method 800 for performing a processing sequence, such as performing a processing sequence on a substrate 13 disposed within a processing volume 134 of a plasma processing chamber 150. The processing volume 134 may also be referred to as a processing region. FIGS. 9, 10, and 11 show exemplary schematic bottom views of an exemplary field generation system 101 during one or more of the activities shown in FIG. 8. Thus, for clarity, FIGS. 8 and 9, 10, and 11 are described together herein. Method 800 may begin with activity 802, which includes a first power circuit including one or more of source drivers 402, 404, 406, 408, 410, 412, 502, 504, 506 biasing at least two of a plurality of planar coils in planar coil region 112 to affect plasma 11 in central region 160 of plasma processing chamber 150, by varying the absolute magnitude of the current applied to at least two of a plurality of planar coils (e.g., two or more of radial coils 102F, 102G, 102H, 102I, 102J, 102K) compared to the absolute magnitude of the current applied to at least two of a plurality of concentric coils (e.g., two or more concentric coils 102A, 102B, 102C, 102D, 102E) in concentric coil region 118, to vary the radial flux and azimuthal flux in central region 160. Varying the radial flux and azimuthal flux in central region 160 of plasma 11 will vary the magnetic field and plasma density in central region 160. In some embodiments, the first power circuit may be configured to bias adjacent planar coils such that the current flowing through the coils is in opposite directions. In some embodiments, the planar coil region includes an even number of planar coils. Adjacent planar coils may be wound oppositely or biased oppositely to produce opposite fluxes when driven. In one example, as shown in FIG. 4, the radial coils are wound in the same direction, but may be reversely biased by a source driver to produce opposite fluxes. Alternatively, although not shown, one radial coil may be wound clockwise while an adjacent coil is wound counterclockwise such that the adjacent coils produce magnetic field fluxes of opposite orientation when biased by a source driver. In these examples, the field generation system 101 in FIG. 9 includes six planar coils (e.g., radial coils 102F, 102G, 102H, 102I, 102J, 102K) in planar coil region 112. In one mode of operation during method 800 for performing a processing sequence, half of the planar coils (e.g., radial coils 102G, 102I, 102K) may be biased in the positive direction while the other half of the planar coils (e.g., radial coils 102F, 102H, 102J) may be biased in the negative direction, as shown in FIG. 9. In another mode of operation during method 800 for performing a processing sequence, half of the planar coils (e.g., radial coils 102F, 102H, 102J) may be biased in the positive direction while the other half of the planar coils (e.g., radial coils 102G, 102I, 102K) may be biased in the negative direction, as shown in FIG. 10. At operation 804, a second power circuit (e.g., one or more of source drivers 302, 304, 306, 308, 310, 312) biases a concentric coil region 118 of at least two concentric coils (e.g., concentric coils 102A, 102B, 102C, 102D, 102E) to affect plasma 11 in an outer region 170 of plasma processing chamber 150. In some embodiments, the second power circuit may be configured to bias adjacent concentric coils in opposite directions (e.g., a positive direction and a negative direction). The second power circuit may be coupled to the concentric coils in the concentric coil region 118 and may be configured to bias the concentric coils in the concentric coil region 118 to affect plasma 11 in an outer region 170 of plasma processing chamber 150 by changing an absolute magnitude of a current applied to the concentric coils as compared to an absolute magnitude of a current applied to planar coils (e.g., radial coils 102F, 102G, 102H, 102I, 102J, 102K), to change a radial flux in an outer region 170 of plasma processing chamber 150. Changing the radial flux in the outer region 170 changes the magnetic field and plasma density in the outer region 170. In some embodiments, operation 804 may occur before operation 802. In other words, the coils in the concentric region 118 may be biased before, after, or simultaneously with the coils in the planar coil region 112 being biased. In some embodiments, as will be further discussed below, some coils may be in a closed position (e.g., radial coils 102F, 102I), some coils may be biased in a positive direction (e.g., radial coils 102G, 102J), and some coils may be biased in a negative direction (e.g., radial coils 102H, 102K), as shown in FIG. 11. Generally, a peak of axial flux exists at the center of each coil in the planar coil region 112. As a result, cross-coupling can be achieved between a pair of positively biased coils and negatively biased coils (e.g., radial coils 102H, 102J) and between another pair of positively biased coils and negatively biased coils (e.g., radial coils 102G, 102K). This smoothing and cross-coupling can help smear a local minimum of plasma 11 at the center of each coil in the planar coil region and at a central region 160 of plasma 11. In some embodiments, each coil may be controlled and manipulated to create a stronger magnetic field for one side of plasma 11 as compared to the other side, which may be desirable if there are issues in the plasma processing system 100 that result in non-concentricity. In some embodiments, at least two of the plurality of planar coils in the planar coil region 112 include a plurality of coil layers. At least two of the plurality of concentric coils in the concentric coil region 118 may also include a plurality of coil layers. The planar coil region 112 may include an even number of coils. In some embodiments, the first power circuit may include at least three power supplies (e.g., source drivers) configured to drive an even number of planar coils. The first power circuit may include a power supply (e.g., source driver) for each of at least two of the plurality of planar coils. In some embodiments, the first power circuit is configured to bias at least two of the plurality of planar coils in the planar coil region 112 by driving at least two planar coil regions (e.g., radial coils 102F, 102G, 102H, 102I, 102J, 102K) with a low frequency, and the second power circuit may be configured to bias at least two of the plurality of concentric coils in the concentric coil region 118 by driving at least two of the plurality of concentric coils (e.g., concentric coils 102A, 102B, 102C, 102D, 102E) with a continuous direct current. In some embodiments, at least two of the plurality of planar coils (e.g., radial coils 102F, 102G, 102H, 102I, 102J, 102K) in the planar coil region 112 can affect the plasma in the central region 160 of the plasma processing chamber through a metal plate (e.g., showerhead 230) having a low magnetic permeability, as described above with reference to FIG. 1. At least two of the plurality of concentric coils (e.g., concentric coils 102A, 102B, 102C, 102D, 102E) in the concentric coil region 118 can affect the plasma in the outer region 170 of the plasma processing chamber through the metal plate. Example of Plasma Processing in the Central Region FIG. 12 is a schematic bottom view of an example of the planar coil region 112, which is a simplified view of the planar coil region 112 shown in FIG. 4. FIG. 12 is provided to help illustrate an example of a method for achieving greater plasma uniformity over time in the central region 160 of the plasma processing chamber 150 by applying a bias to two or more radially opposed coils 102F-K within the planar coil region 112. As noted in activity 804 of method 800 above, one or more of the second power circuits may also be used to bias at least two of the concentric coils within the concentric coil region 118 to affect the plasma 11 formed in the outer region 170 of the plasma processing chamber 150. However, for ease of discussion, the discussion of controlling the components of the concentric coil region 118 is intentionally omitted below, and only the discussion of controlling plasma uniformity within the central region 160 is discussed herein. In this example, at a first time T 1 ， The source drivers 402, 406, 408, and 412 apply a first bias voltage to the radial coils 102F, 102H, 102I, and 102K, respectively. The first bias voltage may include a uniform bias voltage applied to all of the coils 204A in the radial coils 102F, 102H, 102I, and 102K. In this case, the magnetic field lines F generated by the current flowing through the coils 204A within the radial coils 102F, 102H, 102I, and 102K 1 will form a zero region N 1 and N 2 , along which the magnetic field of the zero region N 1 and N 2 is actually at a minimum. As shown in the figure, due to the symmetric arrangement of the coil regions and the applied symmetric bias voltage, the zero regions N 1 and N 2 are symmetrically aligned between the biased radial coils 102F, 102H, 102I, and 102K and will include a zero point C located at the center of the planar coil region 112 1 . The zero point C that coincides with the intersection points of the zero regions N l and N 2 will undesirably form a low plasma density region above the center of the substrate disposed within the processing volume 134 of the plasma processing chamber 150. l However, it has been found that by applying a second bias voltage that is non-uniformly applied to all of the radial coils 102F, 102H, 102I, and 102K at a second time T the zero regions and the zero point can be offset relative to the center of the processing volume and / or the zero regions and the zero point formed at a first time T 2 . As schematically shown in FIG. 12, by increasing the bias voltage and thus increasing the current flowing through one or more of the coil regions (e.g., the radial coils 102H and 102I), the zero regions and the zero point can be offset to an orientation different from the zero regions and the zero point created at the first time T 1 . In this example, at time T 1 created. In this example, at time T 2, magnetic field lines F generated by the asymmetric current flowing through coil 204A within radial coils 102F, 102H, 102I, and 102K 2 form a zero region N 3 and N 4 and a zero point C 2 . Thus, by using controller 126 and the software program stored in memory 128, the current flowing through each of radial coils 102F, 102G, 102H, 102I, 102J, 102K can be adjusted over time such that the zero region and the zero point can be offset relative to the XY plane over time, this XY plane being parallel to the surface of the substrate set within the processing volume of the plasma processing chamber. Accordingly, the ability to adjust the position of the zero region and the zero point over time is used to obscure and balance the effect of the formation of the zero region and the zero point on the plasma density formed on the surface of the substrate being processed in the plasma processing chamber. In some specific embodiments, two or more different adjacent coil regions are sequentially biased over time to cause the zero region and the zero point to translate around the symmetry center of the plasma processing chamber. In one example, a first pair of adjacent opposing coil regions, such as a first pair of coil regions (e.g., radial coils 102H and 102K) and a second pair of coil regions (e.g., radial coils 102F and 102I), are each biased at a first time, then a second pair of adjacent opposing coil regions, such as a third pair of coil regions (e.g., radial coils 102G and 102J) and the second pair of coil regions (e.g., radial coils 102F and 102I), are each biased at a second time, and then a third pair of adjacent opposing coil regions, such as the third pair of coil regions (e.g., radial coils 102G and 102J) and the first pair of coil regions (e.g., radial coils 102H and 102K), are each biased at a third time. Thus, applying a bias voltage to an adjacent pair of coil regions (such as radial coils 102F and 102G) or two adjacent pairs of opposing coil regions (such as the first pair of radial coils 102H and 102K and the second pair of radial coils 102F and 102I), and then transferring to the next adjacent pair of coil regions (such as radial coils 102G and 102H) or two adjacent pairs of opposing coil regions (such as the second pair of radial coils 102F and 102I and the third pair of radial coils 102G and 102J), etc., can be sequentially performed multiple times in plasma processing, thereby being used to blur and balance the influence of the formation of the zero region and the zero point on the plasma density formed on the substrate surface. In another example, during plasma processing, around the central axis of the planar coil region 112, applying a bias voltage to two adjacent pairs of opposing coil regions is continuously performed multiple times in a clockwise or counterclockwise direction, then transferred to the next two adjacent pairs of opposing coil regions, and then transferred to the next two adjacent pairs of opposing coil regions, etc. Other considerations The term "coupled" is used herein to refer to a direct or indirect coupling between two objects. For example, if object A physically contacts object B and object B contacts object C, then objects A and C can still be considered to be coupled to each other - even if objects A and C do not directly physically contact each other. For example, a first object can be coupled to a second object even if the first object has never directly physically contacted the second object. Although the foregoing relates to specific embodiments of the present disclosure, other and further specific embodiments can be contemplated without departing from the basic scope of the foregoing, and the scope of the foregoing is determined by the following claims. 11: Plasma 13: Substrate 100: Plasma processing system 101: Field generation system 102A - 102E: Concentric coils 102F - 102K: Radial coils 103: Power transmission system 105: Substrate holder 106: Support structure 110: Generator 111: RF filter 112: Planar coil region 114: Bias electrode 116: Coolant channel 117: Plate 118: Concentric coil region 119: Process gas source 126: System controller 127: Central processing unit (CPU) 128: Memory 129: Support circuitry 130: Chamber body 131: Sidewall 132: Chamber base 133: Chamber lid 134: Processing volume 140: Substrate support assembly 141: Isolation ring 150: Plasma processing chamber 160: Central region 170: Outer region 180: Showerhead 182: Gas boosting region 184: Opening 202: Multilayer concentric coil 202A: Coil 204: Planar coil 204A: Coil 230: Showerhead 302: Source driver 304 - 308: Source drivers 402 - 408: Source drivers 502 - 506: Source drivers 800: Method 802 - 804: Activities Reference may be made to multiple specific embodiments to more particularly illustrate the present disclosure as briefly summarized above, to more fully understand the above - described features of the present disclosure. The accompanying drawings illustrate some of the specific embodiments. However, it should be noted that the accompanying drawings only illustrate exemplary specific embodiments and should not be considered as limiting the scope of the specific embodiments, and other equivalent specific embodiments are admitted. FIG. 1 is a simplified schematic side cross - sectional view of a plasma processing system according to certain specific embodiments of the present disclosure, and the plasma processing system can be configured to practice the methods described herein. FIG. 2 is a schematic side - view cross - sectional isometric view of a field generation system according to one or more specific embodiments of the present disclosure. FIG. 3 is a schematic bottom view of a field generation system according to certain specific embodiments of the present disclosure. FIG. 4 is a schematic bottom view of an exemplary planar coil region of a field generation system according to certain specific embodiments of the present disclosure. FIG. 5 is a schematic bottom view of an exemplary planar coil region of a field generation system according to certain specific embodiments of the present disclosure. FIG. 6 is a schematic diagram of a power circuit component of a power transmission system of a plasma processing system according to certain specific embodiments of the present disclosure. FIG. 7 is a schematic diagram of a power circuit component of a power transmission system of a plasma processing system according to certain specific embodiments of the present disclosure. FIG. 8 is a flowchart depicting a method for performing a plasma processing sequence in accordance with one or more specific embodiments described herein. FIG. 9 is a schematic bottom view of a field generation system during a plasma processing sequence in accordance with certain specific embodiments of the present disclosure. FIG. 10 is a schematic bottom view of a field generation system during a plasma processing sequence in accordance with certain specific embodiments of the present disclosure, such as a processing sequence performed on a substrate disposed in a processing region of a plasma processing chamber. FIG. 11 is a schematic bottom view of a field generation system during a processing sequence in accordance with certain specific embodiments of the present disclosure. FIG. 12 is a schematic bottom view of a central region of a field generation system during a plasma processing sequence in accordance with certain specific embodiments of the present disclosure. For the sake of assisting understanding, the same reference numerals have been used as much as possible to label the same elements common in the drawings. It is contemplated that the elements and features of one specific embodiment may be beneficially incorporated into other specific embodiments without further description. Domestic deposit information (please note in the order of deposit institution, date, number) None Foreign deposit information (please note in the order of deposit country, institution, date, number) None 101: Field generation system 102A - 102E: Concentric coils 102F - 102G: Radial coils 112: Planar coil region 116: Coolant channel 118: Concentric coil region 202: Multilayer concentric coil 202A: Coil 204: Planar coil 204A: Coil

Claims

1. A plasma processing chamber, comprising: a planar coil region including a plurality of planar coils, wherein each of the plurality of planar coils includes a coil having a first end and a second end, wherein the plurality of planar coils are arranged in a circular array centered along a first point and positioned adjacent to each other in a first plane, each of the plurality of planar coils including a center point set apart from the first point by a distance, and each of the plurality of planar coils having a first portion aligned parallel to the first plane; a first power supply circuit coupled to at least two of the plurality of planar coils, wherein the first power supply circuit is configured to bias at least two of the plurality of planar coils to influence a plasma formed in a central region of the plasma processing chamber; and a concentric coil region including a first concentric coil and a second concentric coil, wherein at least a portion of the planar coil region is surrounded by the first concentric coil and the second concentric coil. The first concentric coil includes a first coil having a first diameter measured in a direction parallel to the first plane; the second concentric coil includes a second coil having a second diameter measured in a direction parallel to the first plane; the first and second concentric coils have a central axis including the first point, and the first diameter is smaller than the second diameter; and a second power supply circuit coupled to the first and second concentric coils, wherein the second power supply circuit is configured to bias the first and second concentric coils to alter a characteristic of the plasma formed in an external region of the plasma processing chamber.

2. The plasma processing chamber as claimed in claim 1, wherein: Each of the plurality of planar coils includes a plurality of coil layers, wherein each of the plurality of coil layers is aligned parallel to the first plane; and both the first concentric coil and the second concentric coil include a plurality of coil layers.

3. The plasma processing chamber as claimed in claim 1, wherein: The first power supply circuit is further configured to bias adjacent planar coils in opposite directions; The second power supply circuit is further configured to bias adjacent concentric coils in opposite directions.

4. The plasma processing chamber as claimed in claim 1, wherein: The planar coil region comprises an even number of planar coils; and adjacent planar coils are wound in opposite directions to produce opposite flux when driven.

5. The plasma processing chamber as claimed in claim 4, wherein the first power supply circuit includes at least three drivers configured to drive the even number of planar coils.

6. The plasma processing chamber as claimed in claim 1, wherein the first power supply circuit includes a driver for each of the plurality of planar coils.

7. The plasma processing chamber as claimed in claim 1, wherein: The first power supply circuit is configured to bias at least two of the plurality of planar coils by driving them at a low frequency. The second power supply circuit is configured to bias the first concentric coil and the second concentric coil by driving the first concentric coil and the second concentric coil with a continuous DC current.

8. The plasma processing chamber as claimed in claim 1, wherein: The first power supply circuit is configured to bias at least two of the plurality of planar coils by changing an absolute value of a current applied to at least two of the plurality of planar coils compared to an absolute value of a current applied to the first and second concentric coils to change a radial flux in the central region, thereby influencing a plasma in a central region of the plasma processing chamber; and changing the radial flux in the central region changes a magnetic field and a plasma density in the central region.

9. The plasma processing chamber as claimed in claim 1, wherein: The second power supply circuit is configured to bias the first concentric coil and the second concentric coil by changing an absolute value of a current applied to the first concentric coil and the second concentric coil compared to an absolute value of a current applied to at least two of the plurality of planar coils to change a radial flux in the outer region, thereby affecting a plasma in an outer region of the plasma processing chamber; and changing the radial flux in the outer region changes a magnetic field and a plasma density in the outer region.

10. The plasma processing chamber as claimed in claim 1, wherein: At least two of the plurality of planar coils influence the plasma in the central region of the plasma processing chamber through a metal plate having a high permeability; and the first concentric coil and the second concentric coil influence the plasma in the outer region of the plasma processing chamber through the metal plate.

11. A plasma processing chamber, comprising: a planar coil region including a plurality of planar coils, each of the plurality of planar coils including a coil disposed between a first end and a second end and having a first portion aligned parallel to a first plane, wherein the plurality of planar coils are arranged in a circular array centered along a central axis and the plurality of planar coils are azimuthally adjacent in the circular array; a first power supply circuit coupled to at least two of the plurality of planar coils, wherein the first power supply circuit is configured to bias at least two of the plurality of planar coils to influence a plasma formed in a central region of the plasma processing chamber; and a concentric coil region including a first concentric coil and a second concentric coil, wherein at least a portion of the planar coil region is surrounded by the first concentric coil and the second concentric coil, the first concentric coil including a first coil having a first diameter measured in a direction parallel to the first plane. The second concentric coil includes a second coil having a second diameter measured in a direction parallel to the first plane, the first and second concentric coils being centered along the central axis, the first and second concentric coils being wound along the central axis, and a second power supply circuit coupled to the first and second concentric coils, wherein the second power supply circuit is configured to bias the first and second concentric coils to alter a characteristic of the plasma formed in an external region of the plasma processing chamber.

12. The plasma processing chamber as claimed in claim 11, wherein: Each of the plurality of planar coils includes a plurality of coil layers, wherein each of the plurality of coil layers is aligned parallel to the first plane; and both the first concentric coil and the second concentric coil include a plurality of coil layers.

13. The plasma processing chamber as claimed in claim 11, wherein: The first power supply circuit is further configured to bias adjacent planar coils in opposite directions; The second power supply circuit is further configured to bias adjacent concentric coils in opposite directions.

14. The plasma processing chamber as claimed in claim 11, wherein: The planar coil region comprises an even number of planar coils; and adjacent planar coils are wound in opposite directions to produce opposite flux when driven.

15. The plasma processing chamber as claimed in claim 11, wherein: The first power supply circuit is configured to bias at least two of the plurality of planar coils by driving them at a low frequency. The second power supply circuit is configured to bias the first concentric coil and the second concentric coil by driving the first concentric coil and the second concentric coil with a continuous DC current.

16. The plasma processing chamber as claimed in claim 11, wherein: The first power supply circuit is configured to bias at least two of the plurality of planar coils by changing an absolute value of a current applied to at least two of the plurality of planar coils compared to an absolute value of a current applied to the first and second concentric coils to change a radial flux in the central region, thereby influencing a plasma in a central region of the plasma processing chamber; and changing the radial flux in the central region changes a magnetic field and a plasma density in the central region.

17. The plasma processing chamber as claimed in claim 11, wherein: The second power supply circuit is configured to bias the first concentric coil and the second concentric coil by changing an absolute value of a current applied to the first concentric coil and the second concentric coil compared to an absolute value of a current applied to at least two of the plurality of planar coils to change a radial flux in the outer region, thereby affecting a plasma in an outer region of the plasma processing chamber; and changing the radial flux in the outer region changes a magnetic field and a plasma density in the outer region.

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