Apparatus and method for modulating spatial distribution of plasma and ion energy using frequency dependent transmission lines

Abstract

A system includes a chamber including a first region and a second region. The chamber is configured to generate and contain a plasma within the second region. The system includes a transmission line located in the first region. The transmission line includes a plurality of sections, where a single section of the plurality of sections includes one or more L-C filters, the L-C filters having respective cut-off frequencies. The transmission line includes a transmission line input. A signal source is electrically coupled to the transmission line input to feed an input signal to the transmission line input. The one or more L-C filters pass low frequency components of the input signal, but localize high frequency components of the input signal to selected sections of the transmission line.

Description

Priority claim

[0001] The present application relates to an apparatus and method for modulating the spatial distribution of plasma and ion energy using frequency-dependent transmission lines. This application claims priority to U.S. Provisional Patent Application No. 63 / 368,138, filed on July 11, 2022, entitled "APPARATUS AND METHOD FOR MODULATING SPATIAL DISTRIBUTION OF PLASMA AND ION ENERGY USING FREQUENCY-DEPENDENT TRANSMISSION LINE", the entire contents of which are incorporated by reference. Background Art

[0002] Plasma deposition is a process that is used to deposit thin films on a substrate using a plasma source. The plasma can be generated in a plasma chamber by radio frequency (RF) current or direct current (DC). For the manufacture of semiconductor devices, uniformity of thin film deposition across the substrate is highly desirable. The uniformity of deposition can result in uniformity in the manufactured devices with substantially the same electrical properties. In a deposition process, uniformity across the substrate or across the wafer is controlled by many factors, such as spatial control of the induced electric field that excites and maintains the plasma, reaction rate, or gas distribution design. The induced electric field controls the potential in the plasma. Modulating the spatial distribution and ion energy of the plasma can provide many advantages for deposition. The spatial distribution and angular distribution of ion energy can be controlled by changing parameters that affect the properties of the bulk plasma, and by changing the electrical parameters (e.g., voltage, frequency) of the signal that excites the induced electric field. Methods and systems for modulating the spatial distribution and ion energy of the plasma are constantly developing. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] The materials described herein are illustrated in the accompanying drawings by way of example rather than by way of limitation. For simplicity and clarity of illustration, the elements shown in the drawings are not necessarily drawn to scale. For example, for clarity, the size of some elements may be enlarged relative to other elements. In addition, for clarity of discussion, various physical features may be represented in their simplified "ideal" form and geometric shapes, but it is still to be understood that the actual implementation may only be close to the ideal shown in the figure. For example, smooth surfaces and square intersections may be drawn while ignoring the limited roughness, rounded corners and imperfect angular intersection features of the structure formed by nanofabrication technology. In addition, where deemed appropriate, the accompanying drawings are repeated between the figures to represent corresponding or similar elements.

[0004] Figure 1According to at least one example, an apparatus is described.

[0005] Figures 2 to 4 A transmission line is described according to at least one example.

[0006] Figure 5 A simulated frequency response of an LC filter of a transmission line is depicted according to at least one example.

[0007] According to at least one example, Fig. 6A Plotted to show the voltage developed in the transmission line; Figure 6B depicts an enlarged graph showing the voltage; and Figure 6C The depiction shows a low frequency signal and a high frequency signal applied to the transmission line.

[0008] Figure 7 According to at least one example, a flowchart of a method is depicted.

[0009] Figure 8

[0011] According to at least one example, a processor system having a machine-readable storage medium having instructions that, when executed, cause the processor to modulate a plasma is described. DETAILED DESCRIPTION

[0010] An apparatus and method for modulating the spatial distribution and ion energy of a plasma using frequency-dependent transmission lines is described according to at least one example. In the following description, several specific details, such as structural diagrams, are set forth to provide a more complete understanding of the examples of this disclosure. It will be apparent to those skilled in the art that the examples of the present disclosure may be implemented without these specific details. In other cases, well-known functions (e.g., RF sources) are described more simply to avoid unnecessarily obscuring the examples of the present disclosure. In addition, it will be understood that the different examples shown in the drawings are merely illustrative representations and are not necessarily drawn to scale.

[0011] In some cases, in the following description, well-known methods and devices are represented in the form of block diagrams rather than in the form of details to avoid blurring the present disclosure. Mentioning "an example" or "one example" or "some examples" throughout this specification refers to the specific features, structures, functions or characteristics described in conjunction with the examples being included in at least one example of the present disclosure. Therefore, the phrases "in an example" or "in an example" or "at least one example" or "some examples" appearing in various places in this specification do not necessarily refer to the same examples of the present disclosure. In addition, specific features, structures, functions or characteristics can be combined in any suitable manner in one or more examples. For example, the first example can be combined with the second example anywhere where the specific features, structures, functions or characteristics associated with the first example and the second example are not mutually exclusive.

[0012] In this article, "coupled" and "connected" together with their derivatives may be used herein to describe the functional or structural relationship between components. These terms are not intended to be synonymous with each other. In contrast, in a particular example, "connected" can be used to refer to two or more elements being in direct physical, optical or electrical contact with each other. In this article, "coupled" can be used to refer to two or more elements being in direct or indirect physical, electrical or magnetic contact with each other (with other intermediate elements in between), and / or two or more elements cooperating or acting on each other (e.g., in a cause-and-effect relationship).

[0013] As used herein, "above," "below," "between," and "on" may generally refer to the relative position of one component or material with respect to other components or materials where such physical relationship is noteworthy. Unless these terms are modified by "directly" or "directly," one or more intervening components or materials may be present. Similar distinctions will apply in the case of an assembly of components. As used throughout the specification and claims, a list of items linked with the terms "at least one" or "one or more" may mean any combination of the listed terms.

[0014] "Adjacent" in this document may generally refer to a position where one thing is in close proximity (eg, next to or close to, with one or more things between them) or adjacent to (eg, adjacent to) another thing.

[0015] Unless otherwise expressly specified when used, the terms "substantially equal", "about equal" and "approximately equal" mean that there is no accidental variation between the two things described. In the art, such variation usually does not exceed + / -10% of the reference value.

[0016] As used herein, a "coil" may generally refer to a form of inductor that includes a wire or other conductor wound into one or more turns, typically in a circular shape. In at least one example, the coil may be in the form of a flat spiral, or solenoid, adjacent to a flat, dome-shaped, or conical dielectric window. In at least one example, geometric factors, such as the number of turns, the spacing between turns, the diameter and length of the coil, and other dimensions (e.g., wire thickness, and the distance of the wire from the plasma), may also affect the inductance of the coil.

[0017] As used herein, a "transmission line" may generally refer to a plurality of conductive elements or segments electrically coupled together. In at least one example, a transmission line may be constructed from discrete elements (e.g., inductors, capacitors). In at least one example, a single conductor of a transmission line may be represented as an inductor L shunted by a distributed capacitance C per unit length, where the distributed capacitance is proportional to the dielectric constant of the dielectric material between the conductors.

[0018] As used herein, a "terminal" may generally refer to the end of a conductor or electronic component (e.g., a wire) that may be a connection point to another conductor or electronic component. When referring to a coil, in at least one example, a terminal is the end point of a winding. When referring to a coil segment, in at least one example, the coil segment may include terminals at the beginning and end of the coil segment conductor.

[0019] In this document, an "inductor" may generally refer to a passive electronic device that stores magnetic energy generated by a current flowing through it. In at least one example, an inductor may include a conductor (e.g., a metal wire) that can couple an electrically generated magnetic field to another nearby conductor, thereby generating a voltage and current in the second conductor. In at least one example, the magnetic field may be generated by a current flowing in a first conductor according to Faraday's law of induction. A conductor has an inductance property that is a function of the magnitude of the current in the conductor and the shape or geometry of the conductor. Although any conductor can be an inductor, conductors of certain shapes have stronger inductance than conductors of other shapes. In at least one example, a straight conductor has a very small inductance, depending on its diameter and length. In at least one example, a straight conductor may be wound into a coil so that the inductance is multiplied by the number of windings per unit length, thereby strengthening the overall magnetic field due to the mutual additive coupling of the magnetic fields between each winding. In at least one example, the magnetic field coupling from each winding generates a multiplication of the magnetic field generated by the straight conductor according to Ampere's law. In at least one example, the coil may be a planar coil, a spiral coil, such as a solenoid or a conical spiral coil.

[0020] As used herein, "capacitor" may generally refer to a passive electronic device that stores charge and electrical energy in the form of an electric field. In at least one example, a capacitor generally has at least two conductive plates that are close to each other and separated by a dielectric material. In at least one example, the dielectric material may be air (or other gas) or a vacuum. In at least one example, the dielectric material may generally be a solid or liquid material, such as a polymer, ceramic, or semi-liquid electrolyte. In at least one example, opposite charges may accumulate on adjacent plates, forming an electric field from plate to plate via a dielectric. The electric field may store electrical energy.

[0021] As used herein, "plasma" may generally refer to a gaseous state containing charged particles, such as positively or negatively charged atomic or molecular ions and electrons. Plasma is considered the fourth state of matter.

[0022] As used herein, the "spatial distribution of a plasma" may generally refer to the arrangement or pattern of ions in the plasma. In at least one example, the arrangement or pattern of the ions indicates the distance between the ions or the density of the ions in the plasma.

[0023] As used herein, "modulate" may generally refer to changing or adjusting, and the term "modulating a plasma" may generally refer to changing the spatial distribution and ion energy of the plasma.

[0024] As used herein, "inductively coupled plasma (ICP)" may generally refer to a plasma generated by a time-varying magnetic field radiated by a primary inductor or plasma antenna (usually in the form of a coil) conducting a radio frequency (RF) current. In at least one example, a low concentration of ionized atoms or molecules and free electrons in a gas may be generated in the discharge. In at least one example, the slightly ionized gas may be considered as a secondary inductor coupled to the plasma antenna (which may be considered as the primary inductor of a transformer), wherein the plasma may be considered as the secondary inductor of the transformer coupled to the primary inductor. In at least one example, the gas may pass through an electromagnetic field generated by an adjacent ICP antenna, wherein charges may be accelerated by a time-varying electric field combined with a time-varying magnetic field (according to Faraday's law of induction and Faraday-Maxwell equations). In at least one example, the accelerated electrons may collide with neutral atoms or molecules to produce more ions and secondary electrons, establishing a plasma density of charged particles. In at least one example, the magnitude of particle acceleration and the accompanying collision velocity are proportional to the strength of the electric field, which in turn is proportional to the strength of the magnetic field. In at least one example, the strength of the magnetic field is proportional to the magnitude of the current flowing in the ICP antenna.

[0025] As used herein, a "tuning section" may generally refer to a portion of an ICP antenna. In at least one example, a tuning section may be a region or segment that is specifically tuned or configured to provide more, less, or different power than another region or segment, thereby changing the spatial uniformity of the plasma.

[0026] As used herein, a "non-tuned portion" may generally refer to a portion of an ICP antenna. In at least one example, a non-tuned portion may be a region or segment that is not specifically tuned or configured to provide more, less, or different power than another region or segment to change the spatial non-uniformity of the plasma. In at least one example, a non-tuned portion may also generally be referred to as a background RF drive signal region or segment that is configured to sustain a plasma.

[0027] In this document, a "tank circuit" may generally refer to a parallel combination of an inductor and a capacitor. In at least one example, the tank circuit has a characteristic resonant frequency f0, which is determined by the values ​​of the inductor L and the capacitor C, where f0 = 1 / [2p√LC]. In at least one example, the tank circuit has a resonance curve, which is a functional relationship between the circuit impedance and the frequency. In at least one example, the curve is non-monotonic because it has a peak at the resonant frequency. The sharpness and bandwidth of the resonance curve are determined by the quality factor Q of the circuit. "Q" can be defined as the ratio of the energy stored in the electric and magnetic fields of the capacitor and inductor, respectively, to the energy dissipated in the form of heat by the resistive part of the circuit. In at least one example, the resistance may be mainly in the inductor (e.g., as copper loss, skin effect), because it may contain a long thin wire wound into a coil. In at least one example, the smaller the resistance of the coil, the greater the Q value. In at least one example, the Q value can be reduced by inserting a discrete resistor in series with the inductor in the tank circuit. In at least one example, the resonant curve may be broadened by a low circuit Q value (e.g., Q value <10) and sharpened by a high circuit Q value (e.g., Q value >10). In at least one example, the tank circuit exhibits a very large circulating current at or near resonance. In at least one example, the circulating current may be the product of the line current or feed current multiplied by the Q value. In at least one example, very large voltages may also appear across capacitors and inductors due to the large circulating currents. At the same time, in at least one example, the impedance of the tank circuit increases sharply at or near resonance and becomes purely resistive at f0. In at least one example, the resonant tank circuit may have a very high effective resistance that severely reduces the conduction of the RF current at f0. Here, the "tank circuit" is derived from the ability of the circuit to store electrical energy. In at least one example, the tank circuit is a frequency determining component used as an oscillator circuit and a tuned coupling circuit (e.g., present in a tuned RF amplifier stage).

[0028] In this document, "dielectric material" generally refers to a material that is not electrically conductive, such as polymers, ceramics, glass, wood, and the like.

[0029] As used herein, "radio frequency" may generally refer to electromagnetic radiation that oscillates at frequencies in a spectrum that generally includes frequencies from 10 kilohertz (kHz) to 1 terahertz (THz, or 10 15 In at least one example, the upper limit of the radio frequency spectrum may only extend to a few hundred gigahertz (GHz). The term radio frequency may be abbreviated as "RF".

[0030] As used herein, an "RF signal source" or "signal source" may generally refer to an electronic device capable of generating a radio frequency electronic signal. In at least one example, the RF signal source is capable of outputting a significant RF current (e.g., 1 ampere rms or greater) at a significant voltage. In at least one example, an RF signal source for an ICP antenna is typically capable of outputting a current of up to hundreds of amperes at a voltage of up to hundreds of volts, generating significant power.

[0031] As used herein, a "processing tool" generally refers to equipment used in semiconductor manufacturing, also referred to as a "semiconductor processing tool" for semiconductor processing. In at least one example, a processing tool generally includes a vacuum chamber in which processes such as plasma etching of a substrate or plasma-enhanced material deposition are performed. In at least one example, other non-plasma related processes may also be performed in a processing tool.

[0032] Herein, "LC filter" may generally refer to a filter including an inductor L and a capacitor C. In at least one example, the inductance and capacitance of the inductor L and the capacitor C may be selected to pass electrical signals of a specific frequency band, but attenuate or filter out other frequency bands.

[0033] As used herein, a "chuck" may generally refer to a stage or platform upon which a substrate (eg, a wafer) may be secured.

[0034] Herein, an "electrostatic chuck" may generally refer to a platform, which may include an electrode plate and an insulator disposed on the electrode plate.

[0035] In this document, "substrate" may generally refer to a wafer comprising a semiconductor (e.g., silicon) or an insulator (e.g., aluminum nitride, silicon carbide, silicon nitride, aluminum oxide, float glass, borosilicate glass, etc.). The wafer may be a slice of a single crystal semiconductor or insulator. In at least one example, the wafer may also comprise a polycrystalline or amorphous (glass-like) material. In at least one example, the diameter of the wafer is generally between 100 mm and 500 mm, and the thickness is generally between 100 microns and 1 mm.

[0036] As used herein, a "processing chamber" may generally refer to a vacuum chamber of a processing tool into which a substrate may be introduced for processing. In at least one example, the chamber may include a chuck to support the substrate. An example of a processing chamber is a plasma etching chamber.

[0037] As used herein, "chamber" or "plasma chamber" may generally refer to a processing chamber in which a plasma may be generated to perform a process.

[0038] As used herein, a "utility chamber" may generally refer to a chamber or housing on a processing tool in which electronics or other sensitive equipment may be housed and isolated from the processing chamber. In at least one example, an ICP antenna may be housed in the utility chamber and isolated from the typically harsh environment of the processing chamber. In at least one example, the utility chamber may be maintained at a vacuum or atmospheric pressure.

[0039] Herein, the "first area" may generally refer to an area where indoor transmission lines are located.

[0040] As used herein, the "second region" may generally refer to a region within a chamber that may contain a gas or plasma.

[0041] In this article, "separation window" or "dielectric window" can generally refer to a window that separates a chamber into a first area and a second area. In at least one example, the separation window or dielectric window can be constructed of a non-conductive material (e.g., a dielectric) such as a polymer, ceramic, glass, wood, etc.

[0042] As used herein, "spatial control" may generally refer to positional control of a process. In at least one example, spatial control of plasma etching or deposition is achieved by providing spatially resolved coupling of an ICP antenna to the plasma.

[0043] In this document, “input signal” generally refers to a signal of a desired frequency provided by a signal source.

[0044] As used herein, "cutoff frequency" may generally refer to a frequency below which all frequencies are allowed to pass through a filter. In at least one example, a filter may be tuned to have a cutoff frequency of about 200 MHz, in which case frequencies below 200 MHz may pass through the filter, but frequencies above 200 MHz may be blocked.

[0045] As used herein, "coupled" may generally refer to a direct connection of one electronic component to another electronic component. In at least one example, an electric or magnetic field may couple one component to another, where the field is controlled by one component to affect the other component in some way.

[0046] In this document, a “low-frequency signal” or a “low-frequency component” may generally refer to a signal having a frequency range between 0 Hz and 0.5 kHz.

[0047] In this document, "high frequency signal" or "high frequency component" generally refers to a signal having a frequency range greater than 0.5 MHz.

[0048] As used herein, "magnetic field" may generally refer to lines of magnetic flux direction and strength arising from a magnetized material or a current-carrying material.

[0049] As used herein, a "plasma-enhanced process" may generally refer to a semiconductor process, e.g., a process that is aided in some way by a plasma. In at least one example, a plasma-enhanced process is enhanced over a similar or identical process without the plasma. An example is reactive ion etching and plasma-enhanced chemical vapor deposition or plasma-enhanced atomic layer deposition.

[0050] As used herein, "reactive species" may generally refer to ions or neutral radicals formed in a plasma.

[0051] In this document, a "section" or "selected section" may generally refer to a component or portion of a transmission line that includes a number of sections.

[0052] In this context, "localization" may generally refer to allowing a selected frequency (eg, around 10 MHz or higher) to propagate within a selected number of segments or sections of a transmission line.

[0053] As used herein, "ion" may generally refer to an electrically charged atom or molecule. In the context of the present disclosure, an ion may be a gaseous atom or molecule that loses or gains electrons in a plasma.

[0054] In this document, "machine-readable storage medium" generally refers to a memory that stores binary code or data readable by a processor. In at least one example, the machine-readable storage medium may be a non-volatile solid-state storage medium, a magnetic hard disk, an optical disk, and the like.

[0055] In this document, "machine-readable instructions" may generally refer to binary codes stored on a machine-readable storage medium. When executed, in at least one example, the binary codes or instructions may cause a processor to perform specific functions.

[0056] According to at least one example, Figure 1A system 100 is depicted. In at least one implementation, the system 100 includes a chamber 104, a first region 105, a second region 106, a partition window 107, an inlet valve 108, an outlet valve 112, a transmission line 120, a signal source 124, an input terminal 128, a terminal node 132, an electrostatic chuck 136, an electrode plate 140A, an insulator 140B, and a wafer 144.

[0057] In at least one example, the chamber 104 is configured to generate and contain plasma, and in at least one example, the chamber 104 can be divided into a first region 105 and a second region 106 by a partition window 107. In at least one example, the partition window 107 can be made of a non-conductive material (e.g., a dielectric), such as a polymer, ceramic, glass, wood, etc. The first region 105 is also referred to as an antenna region or a transmission line region. The second region 106 is also referred to as a vacuum region or a plasma region (e.g., a region containing plasma).

[0058] In at least one example, the chamber 104 can include an inlet valve 108 through which gas is pumped into the chamber, and an outlet valve 112 for removing the gas. In at least one example, the gas is generally contained within the second region 106. In at least one example, although the processing chamber 104 is shown as a rectangle, it can be created in other suitable shapes, such as (but not limited to) a dome shape.

[0059] In at least one example, the system 100 includes a transmission line 120 located in the first region 105. In at least one example, the transmission line 120 includes a plurality of segments S1-S2. N (also called transmission line segment S1-S N ). In at least one example, a single segment S1-S N Each may include one or more LC filters ( Figure 1 1 . In at least one example, the signal source 124 is electrically connected to the transmission line 120 at the input terminal 128. The signal source 124 feeds a signal of a desired frequency to the transmission line 120. In at least one example, the transmission line 120 has a terminal node 132 that is coupled to a common potential (hereinafter referred to as "ground"). In at least one example, the terminal node 132 can be capacitively coupled to ground.

[0060] In at least one example, the system 100 includes an electrostatic chuck 136 located in the second region 106. The electrostatic chuck 136 may include an electrode plate 140A and an insulator 140B disposed on the electrode plate 140A. In at least one example, the insulator 140B may include a dielectric material (including ceramics), such as aluminum oxide (Al2O3), silicon dioxide (SiO2), silicon nitride (Si3N4), and / or sapphire. In at least one example, a wafer or semiconductor substrate 144 is disposed on the electrostatic chuck 136.

[0061] In operation, in at least one example, the system 100 controls plasma-assisted deposition, cleaning, or etching on the substrate 144 by spatially modulating the energy distribution of ions in the plasma generated in the chamber 104. In at least one example, the system 100 also controls the spatial distribution and ion energy of the plasma by varying electrical parameters, such as the frequency and voltage of the applied signal fed to the transmission line 120. In at least one example, the system 100 is operable to spatially control plasma processes on the substrate 144, such as PECVD, PEALD, and plasma cleaning and ion etching processes (e.g., reactive ion etching).

[0062] Although the transmission line 120 is depicted as having a linear structure, in at least one example, the transmission line 120 can have other suitable shapes. In at least one example, the transmission line 120 can be wound into a coil, such as a pancake-shaped coil.

[0063] Figure 2 A transmission line 120 according to at least one example is depicted. In at least one example, the transmission line 120 includes a plurality of segments S1-S N (i.e., transmission line segment S1-S N ), each of which has at least one LC filter. In at least one example, segment S1 includes three LC filters: a first LC filter formed by inductor L1 and capacitor C1; a second LC filter formed by inductor L2 and capacitor C2; and a third LC filter formed by inductor L3 and capacitor C3. In at least one example, segments S2-S N Each includes three LC filters. In at least one example, the LC filters are configured as low-pass filters that are coupled together to form an LC ladder network. Figure 2 , L1 is coupled to L2 at node 210, and C1 is coupled between node 210 and ground. L2 is coupled to L3 at node 214, and C2 is coupled between node 214 and ground. L3 is coupled to L4 at node 218, and C3 is coupled between node 218 and ground. In at least one example, other inductors L5-L N and capacitor C5-C NSimilarly coupled. In at least one example, a signal source 124 is coupled to L1 at an input terminal 128 to feed a signal of a desired frequency and voltage to the transmission line 120. In at least one example, a resistor R can be coupled in series between the signal source 124 and L1, thereby allowing precise control of the current fed to the transmission line 120. In at least one example, a series capacitor ( Figure 1 A capacitor (not shown) may be coupled between terminal node 132 and ground. In at least one example, a capacitor may capacitively couple terminal point 132 to ground.

[0064] By selecting the inductor L1-L N The inductance value and capacitor C1-C N In at least one example, the LC filter can be configured as a low-pass filter with a respective cutoff frequency. N can have the same capacitance, but the inductor L1-L N There can be different inductors. Because the cut-off frequency of the LC filter is given by the following relationship: In at least one example, the cutoff frequency of the transmission line 120 varies with the position on the transmission line 120 .

[0065] In at least one example, the inductance values ​​are selected so that the inductance of the inductors in the transmission line 120 increases as they are located further downstream in the transmission line 120. In at least one example, the input signal fed to the transmission line 120 passes through inductors with increasingly higher inductance. In at least one example, the following inductance and capacitance values ​​are selected: L1 = 49nH, C1 = 2uF; L2 = 60nH, C2 = 2uF; L3 = 72nH, C3 = 2uF; L4 = 87nH, C4 = 2uF; and L5 = 106nH, C5 = 2uF; In at least one example, L6-L N The other inductors of can be selected such that the inductance of the inductor increases as it is located further downstream in the transmission line 120. In at least one example, C1-C N The capacitance may be different.

[0066] Because the inductance of the inductor increases as it is located further downstream in the transmission line 120, in at least one example, the cutoff frequency of the LC filter decreases as it is located further downstream in the transmission line. In at least one example, the transmission line 120 includes multiple LC filters having cutoff frequencies that decrease along the length of the transmission line 120. Therefore, in at least one example, an input signal propagating through a section of the transmission line 120 is filtered by multiple filters with gradually decreasing cutoff frequencies. The effect of this is that lower frequencies (also referred to as low-frequency components) can pass through the transmission line 120 and can therefore be uniformly applied to the transmission line 120; but higher frequencies (e.g., RF frequencies greater than 10 MHz) are filtered out or attenuated (blocked) by the LC filter section and are therefore localized within the selected LC filter section. Therefore, the low-frequency component passes through one or more LC filters to uniformly apply the low-frequency component to the transmission line. In at least one example, the cutoff potential of the LC filter can be selected to allow a range of low frequency signals (eg, 0 Hz-0.5 kHz) to be uniformly applied to the transmission line 120 while localizing high frequency signals (eg, >0.5 MHz).

[0067] In at least one example, the sixth LC filter (L6, C6) has a cutoff frequency of approximately 1 MHz, the ninth LC filter (L9, C9) has a cutoff frequency of approximately 0.8 MHz, and the eleventh LC filter (L 11 , C 11 ) has a cutoff frequency of about 0.6 MHz. The effect of this is that a 1 MHz signal propagates to the sixth LC filter (L6, C6), a 0.8 MHz signal propagates to the ninth LC filter (L9, C9), and a 0.6 MHz signal propagates to the eleventh LC filter (L 11 , C 11 ). In at least one example, the LC filter can be designed to localize higher frequencies to selected sections of the transmission line 120 while allowing lower frequencies (eg, 0 Hz-0.5 kHz) to propagate through the entire length of the transmission line 120.

[0068] In at least one example, the transmission line 120 is a frequency-dependent structure that is used to control the spatial distribution and ion energy of the plasma by changing the frequency and voltage of the input signal fed to the transmission line. In at least one example, by selecting the frequency of the input signal, the voltage generated by the high-frequency signal can be localized at one or more sections of the transmission line 120. By changing (e.g., varying or adjusting) the frequency of the input signal, in at least one example, the localized voltage generated by the high-frequency signal (e.g., high-frequency component) can be switched from one or more sections to other one or more sections. In at least one example, the high-frequency components are localized in the selected sections by switching the frequency of the input signal fed to the transmission line 120. In at least one example, by changing the amplitude of the high-frequency signal, the localized voltage of the selected section of the transmission line 120 can be increased or decreased. In at least one example, by selecting the frequency of the input signal, only selected sections of the transmission line 120 may be allowed to radiate (couple to the strong electromagnetic (EM) field of the plasma), and by varying the amplitude of the signal, the localized EM radiation may be enhanced or attenuated.

[0069] In at least one example, the frequency-dependent properties of a single transmission line segment can be used to control the spatial distribution and ion energy of an inductively coupled plasma in the plasma chamber 104. Because the coupling efficiency of an inductively coupled plasma to an EM field can be frequency-dependent, in at least one example, plasma characteristics can be spatially controlled. In at least one example, by localizing voltages and currents having selected frequencies within selected segments of the transmission line, the spatial distribution and ion energy of the plasma in regions adjacent to these segments are modulated (e.g., increased or decreased) relative to the portion of the plasma coupled to the transmission line segment, thereby allowing lower frequency RF currents to flow. In at least one example, by changing the amplitude (e.g., voltage) of the input signal, the localized current and voltage levels (and associated EM fields) can be increased or decreased, thereby providing a means to modulate or change (e.g., increase or decrease) the spatial distribution and ion energy of the plasma in these regions. In at least one example, the spatial distribution and ion energy of the plasma in the second region 106 are modulated within the region adjacent to the selected segment of the transmission line 120. In at least one example, the spatial distribution of the plasma is modulated by changing the input signal voltage in a selected section of the transmission line 120 .

[0070] If a high frequency signal is superimposed on a low frequency signal and fed to the transmission line 120, the low frequency signal may be uniformly applied along the transmission line 120. In at least one example, the lower frequency may be lower than the overall cutoff frequencies of the plurality of sections of the transmission line 120, thereby allowing propagation along the entire transmission line 120 to the terminal load. In at least one example, the high frequency signal may be localized within a confined portion of the transmission line 120 including a selected section of the transmission line 120. In at least one example, the frequency of the higher frequency signal may be higher than the cutoff frequency of the selected section of the transmission line. In at least one example, the higher frequency signal may thus be confined to a portion of the transmission line 120 having a cutoff frequency greater than the cutoff frequency of the higher frequency signal. In at least one example, the effect of this is that the selected section of the transmission line 120 will have a higher voltage level than other sections, and thus the spatial distribution of the plasma and the ion energy in the region adjacent to the selected section may be modulated.

[0071] In at least one example, a 1 MHz RF signal may be superimposed on a DC voltage, and the combined signal may be applied to the transmission line 120. In at least one example, the DC voltage may be uniformly present along the transmission line 120. Because the 1 MHz signal may propagate to segment S2, the voltage generated by the 1 MHz signal may be localized in segments S1 and S2. This has the effect that a higher voltage level may exist in segments S1 and S2, while segments S3-S4 may be relatively low. N A lower voltage level may exist at .

[0072] In at least one example, multiple signal sources may feed signals having different frequencies to the transmission line. Figure 3 A transmission line 300 according to at least one example is depicted. In at least one example, the transmission line 300 includes: segments S1-S 14 , a first input terminal 314, a second input terminal 320, and a terminal node 322. In at least one example, the segments S1-S 14 Each includes one or more LC filters ( Figure 3 3. The transmission line 300 includes a terminal node 322 coupled to ground. In at least one example, the low frequency signal is uniformly applied to the transmission line 300. In at least one example, the high frequency signal is localized in the section S5-S6. 10 For example, if the high frequency signal is a 25 MHz signal, then segments S5 and S 10 The cut-off frequency can be set to 20 MHz to localize the high frequency signal in the section S5-S 10 Inside.

[0073] Figure 4 A transmission line 400 according to at least one example is depicted. In at least one example, the transmission line 400 includes a first input terminal 414 and a second input terminal 424. In at least one example, a first signal source 410 feeds a low frequency signal (e.g., a 400 kHz signal) having a frequency f1 to the first input terminal 414. Because the low frequency signal is uniformly applied to the transmission line, in at least one example, the low frequency signal (e.g., a 400 kHz signal) can be used to drive the plasma chamber ( Figure 4 4 (not shown). In at least one example, the signal source 418 feeds a high frequency signal (e.g., a 25 MHz signal) having a frequency f2 to the second input terminal 424. In at least one example, the high frequency signal (e.g., a 25 MHz signal) is localized in the segments S1-S5. In at least one example, a low frequency signal (e.g., a 400 kHz signal) can be used for low power operation, and the high frequency signal (e.g., a 25 MHz signal) can be used to locally excite the segments S1-S5 of the transmission line 400 and / or to ignite the system. In at least one example, the amplitude of the high frequency signal (e.g., a 25 MHz signal) can be adjusted to modulate the spatial distribution of the plasma.

[0074] Figure 5 An exemplary graph 500 showing a plurality of curves is depicted. Figure 5 The single curve in FIG. 1 represents the frequency response of a continuous segment in a transmission line (e.g., transmission line 120). In at least one example, a first transmission line segment including a first LC filter network (e.g., indicated as LC_1) has a cutoff frequency of about 1 MHz (in Figure 5 In at least one example, a signal having a frequency equal to or less than 1 MHz (in Figure 5 In at least one example, a fifth transmission line segment (indicated as LC_5) including a fifth filter network has a cutoff frequency at approximately 600 kHz (indicated as LC_5). Figure 5 In at least one example, a signal having a frequency greater than 600 kHz (in Figure 5 5 on the x-axis) can be attenuated, and signals with frequencies less than 600 kHz can be passed to subsequent sections 6-17. In at least one example, the seventeenth transmission line segment includes a seventeenth LC filter network (e.g., indicated as LC_17) with a cutoff frequency of approximately 270 kHz. Therefore, the signal with the lowest frequency can propagate along the entire length of the transmission line.

[0075] Fig. 6AAn exemplary graph 600A showing simulated localized voltages generated in successive segments of a transmission line is depicted, created in accordance with an example of the present disclosure. Fig. 6A 6, the x-axis of graph 600A represents frequency (normalized at 1.0 on the x-axis in FIG. 6), and the y-axis on the left represents the segments of the transmission line. In at least one example, the magnitude of the localized voltage is represented by a staircase diagram. Graph 600A shows the progressive frequency response of successive transmission line segments, with segment 1 being closest to the signal source and segment 50 being farthest. In this example graph 600A, the segments closer to the signal source (e.g., segments 1-10) may have the highest cutoff frequency and may pass all frequencies ranging from DC to 50 MHz. Beyond segment 10, the cutoff frequencies of successive segments become progressively smaller, thereby limiting the passing of higher frequencies to the closer transmission line segments. The more distant transmission line segments pass progressively lower frequencies. In this example, segment 25 is preferentially excited by a 24.5 MHz signal, which causes approximately 1.5 V in segment 25. Fig. 6A Indicates the localized voltage generated in the section (cross-hatching) of the transmission line that allows the frequency to propagate (the voltage V is not zero) and the localized voltage in the section that does not allow the frequency to propagate (the voltage V is zero). Figure 6B Graph 600B in FIG. 2 shows an enlarged view of the voltage generated in section 25 . Figure 6C An exemplary graph 600C is depicted showing a low frequency signal 602 and a high frequency signal 604 applied to a transmission line 120. The x-axis represents time and the y-axis represents the frequency of the applied signal. In this example, the frequency of the high frequency signal 604 varies periodically. The low frequency signal 602 is uniformly applied to the transmission line 120, while the high frequency signal 604 is used to preferentially excite selected sections of the transmission line 120. In at least one example, the low frequency signal 602 may be approximately 400 kHz, while the high frequency signal 604 may vary (e.g., 24.5 MHz-100 MHz).

[0076] Figure 7 7 is a flow chart of a method 700 for modulating the spatial distribution and ion energy of a plasma according to the disclosure. In at least one example, the blocks herein can be performed by software, hardware, and / or a combination thereof. In block 704, plasma is generated in a plasma chamber (e.g., plasma chamber 104). In at least one example, the plasma chamber includes a plurality of segments (e.g., S1-S2). N ) of a transmission line (eg, transmission line 120), each of these sections has one or more LC filters (eg, L1, C1). These LC filters have respective cutoff frequencies.

[0077] In box 708, in at least one example, a region in the plasma chamber (e.g., plasma chamber 104) is selected. In at least one example, plasma is to be modulated in the selected segment. In at least one example, the method further includes feeding an input signal having a predetermined frequency to the transmission line 120 to localize the generated voltage at one or more of the plurality of segments adjacent to the selected portion of the second region 106. In at least one example, in box 712, an input signal having a predetermined frequency is fed to the transmission line (e.g., transmission line 120) to localize the generated voltage at one or more of the segments (e.g., S5-S10) adjacent to the selected region of the plasma chamber. In at least one example, the predetermined frequency is less than or equal to a cutoff frequency of the one or more LC filters of the selected segments. In box 716, in at least one example, the amplitude of the input signal is varied to adjust the generated localized voltage.

[0078] Figure 8 A system 800 is depicted that includes a machine-readable storage medium including instructions for modulating the spatial distribution and ion energy of a plasma, according to at least one example. The system 800 includes: a memory 804 , a processor 808 , a network 812 , a machine-readable storage medium 814 , and a communication interface 820 .

[0079] In at least one example, memory 804 is a volatile or non-volatile memory. In at least one example, processor 808 is a digital signal processor (DSP), an application specific integrated circuit (ASIC), a general purpose central processing unit (CPU), or low power logic implementing a simple finite state machine to execute methods of modulating the spatial distribution and ion energy of plasma and / or different examples, etc.

[0080] In at least one example, the machine-readable storage medium 814 includes instructions for modulating the spatial distribution and ion energy of the plasma. In at least one example, the instructions, when executed, cause the processor 808 to perform a method that includes generating a plasma in a chamber including a first region and a second region. In at least one example, the first region includes a transmission line having a plurality of segments. In at least one example, a single segment of the plurality of segments includes one or more LC filters. In at least one example, the second region contains the plasma. In at least one example, the instructions, when executed, cause the processor 808 to perform a method that includes selecting a portion of the segment area where the plasma is to be modulated. In at least one example, the instructions, when executed, cause the processor 808 to perform a method that includes feeding an input signal of a predetermined frequency to the transmission line 120 to localize a voltage at one or more segments of the plurality of segments that are adjacent to the selected portion of the second region.

[0081] In at least one example, the instructions, when executed, cause the processor 808 to perform a method that includes changing the amplitude of the input signal to adjust the generated voltage. In at least one example, the instructions, when executed, cause the processor 808 to perform a method that includes changing a frequency of the input signal to switch the localized generated voltage from the one or more sections of the transmission line 120 to one or more other sections of the transmission line 120. In at least one example, the predetermined frequency is less than or equal to a cutoff frequency of the one or more LC filters of the one or more sections. The machine-readable storage medium 814 has machine-readable instructions that, when executed, cause the processor 808 to perform the method of modulating the spatial distribution of plasma and ion energy, as discussed with reference to various examples.

[0082] The program software codes / instructions associated with the various examples may be implemented as a portion of an operating system or a special purpose program, a component, a program, an object, a module, a routine, or other sequence of instructions or an organization of instruction sequences referred to as "program software codes / instructions", "operating system program software codes / instructions", "application software codes / instructions", or simply "software", or firmware embedded in a processor. In at least one example, the program software codes / instructions associated with the processes of the various examples are executed by the processor system 800.

[0083] In at least one example, program software codes / instructions are stored in a computer executable storage medium 814 and executed by the processor 808. Herein, the computer executable storage medium 814 may be a tangible machine readable medium that can be used to store program software codes / instructions and data that, when executed by a computer device, causes one or more processors (e.g., the processor 808) to perform a process.

[0084] Tangible machine-readable media 814 may include storage devices of executable software program codes / instructions and data in various tangible locations, including, for example, ROM, volatile RAM, non-volatile memory and / or cache memory (cache) and / or other tangible memories as mentioned in the present application. In at least one example, portions of program software codes / instructions and / or data may be stored in any of these storage devices and memory devices. In at least one example, program software codes / instructions may be obtained from other storage devices, including, for example, through a centralized server or a peer-to-peer network (peer to peer network), including the Internet. Different portions of software program codes / instructions and data may be obtained at different times and in different communication sessions (communication session) or in the same communication session.

[0085] In at least one example, the software program code / instructions may be obtained in full prior to executing the corresponding software program or application. Alternatively, in at least one example, portions of the software program code / instructions and data may be obtained dynamically, such as in a timely manner, when needed for execution. Alternatively, some combination of these ways of obtaining software program code / instructions and data may occur, such as for different applications, components, programs, purposes, modules, routines, or other instruction sequences or organizations of instruction sequences. Thus, in at least one example, it may not be necessary for the data and instructions to all be located on a tangible machine-readable medium at a particular point in time.

[0086] Examples of tangible computer readable media 814 include, but are not limited to, recordable and non-recordable media such as volatile and non-volatile memory devices, read-only memory (ROM), random access memory (RAM), flash memory devices, floppy disks and other removable disks, magnetic storage media, optical storage media (such as compact disk read-only memory (CD ROM), digital versatile disk (DVD), etc.), etc. When electrical, optical or acoustic or other forms of signals such as carrier waves, infrared signals, digital signals, etc. are transmitted through a tangible communication link, the software program code / instructions may be temporarily stored on such a digital tangible communication link.

[0087] In at least one example, system 100 can be used in a 3-D printing system that includes an electrode. In at least one example, system 100 can be used where a high frequency signal is localized to a selected section of the electrode, but a low frequency signal is applied uniformly throughout the electrode.

[0088] In addition to what is described herein, the examples of the present disclosure may be modified in various ways without departing from the scope of the present disclosure. Therefore, the contents described in the examples herein should only be understood as examples and do not limit the scope of the present disclosure. The scope of the present invention should only be measured with reference to the following claims.

[0089] The following examples are provided to describe different examples, which may be combined with other examples. Likewise, different examples may be combined with other examples without changing the scope of the present invention. For example, Example 7 may be combined with Example 2 or Example 3 or both.

[0090] Example 1: A system comprising: a chamber comprising a first region and a second region, the chamber being configured to generate and contain a plasma within the second region; a transmission line located within the first region, the transmission line comprising a plurality of segments, wherein a single segment of the plurality of segments comprises one or more LC filters, wherein the one or more LC filters have respective cutoff frequencies, and wherein the transmission line comprises a transmission line input; and a signal source electrically coupled to the transmission line input to feed an input signal to the transmission line input; wherein the one or more LC filters pass low frequency components of the input signal but localize high frequency components of the input signal to selected segments of the transmission line.

[0091] Example 2. The system of Example 1, wherein the first region is separated from the second region by a dielectric window.

[0092] Example 3. The system of Example 1, wherein the low frequency component is passed by the one or more LC filters to uniformly apply the low frequency component to the transmission line.

[0093] Example 4. The system of Example 1, wherein the high frequency components are localized to the selected section of the transmission line by selection of the respective cutoff frequencies of the one or more LC filters.

[0094] Example 5. The system of Example 1, wherein the selected section in which the high frequency component is localized is switched by a change in the frequency of the input signal fed to the transmission line.

[0095] Example 6. The system of Example 1, wherein the voltage of the input signal is varied to vary the voltage of the low frequency component uniformly applied to the transmission line.

[0096] Example 7. The system of Example 1, wherein a voltage of the input signal is varied to vary a voltage at the selected segment where the high frequency component is localized.

[0097] Example 8. The system of Example 1, wherein a cutoff frequency of the one or more LC filters decreases as they are located further downstream in the transmission line.

[0098] Example 9. The system of Example 1, wherein the respective cutoff frequencies of the one or more LC filters decrease as the input signal propagates along the transmission line.

[0099] Example 10. A system for modulating the spatial distribution and ion energy of a plasma, the system comprising: a chamber comprising a first region and a second region separated by a separation window; a transmission line located in the first region, the transmission line comprising a plurality of segments, wherein a single segment of the plurality of segments comprises one or more LC filters, the one or more LC filters having respective cutoff frequencies, the transmission line having a transmission line input end; and a signal source electrically coupled to the transmission line input end to feed an input signal to the transmission line; wherein the one or more LC filters pass low frequency components of the input signal but localize high frequency components of the input signal to a selected segment of the transmission line; and wherein the spatial distribution and ion energy of the plasma in the second region are modulated in a region adjacent to the selected segment of the transmission line.

[0100] Example 11. The system of Example 10, wherein the separation window comprises a dielectric.

[0101] Example 12. The system of Example 10, wherein the spatial distribution of the plasma is modulated by variations in the voltage of the input signal.

[0102] Example 13. The system of Example 10, wherein the selected segment in which the high frequency component is localized is switched by a change in the frequency of the input signal.

[0103] Example 14. The system of Example 10, wherein the voltage of the input signal is varied to vary the voltage of the low frequency component on the transmission line.

[0104] Example 15. The system of Example 10, wherein the voltage of the input signal is varied to vary the voltage across the selected segment in which the high frequency component is localized.

[0105] Example 16. A method for modulating the spatial distribution and ion energy of a plasma, the method comprising: providing a chamber comprising a first region and a second region, wherein the first region comprises a transmission line having a plurality of segments, wherein a single segment of the plurality of segments comprises one or more LC filters; generating the plasma within the second region; selecting a portion of the second region where the plasma will be modulated; feeding an input signal of a predetermined frequency to the transmission line to localize the generated voltage at one or more segments of the plurality of segments adjacent to the selected portion of the second region; and varying the amplitude of the input signal to adjust the generated voltage.

[0106] Example 17. The method of Example 16, further comprising varying a frequency of the input signal to switch the localized generated voltage from one or more sections of the transmission line to another one or more sections of the transmission line.

[0107] Example 18. The method of Example 16, wherein the predetermined frequency is less than or equal to a cutoff frequency of the one or more LC filters of the selected segment.

[0108] Example 19. A machine-readable storage medium having machine-executable instructions that, when executed, cause one or more machines to perform a method, the method comprising: generating a plasma in a chamber comprising a first region and a second region, wherein the first region comprises a transmission line having a plurality of segments, wherein a single segment of the plurality of segments comprises one or more LC filters, wherein the second region comprises the plasma; selecting a portion of the second region where the plasma is to be modulated; feeding an input signal of a predetermined frequency to the transmission line to localize a generated voltage at one or more segments of the plurality of segments adjacent to the selected portion of the second region; and varying an amplitude of the input signal to adjust the generated voltage.

[0109] Example 20. The machine-readable storage medium of Example 19, wherein the method further comprises changing a frequency of the input signal to switch the localized generated voltage from the one or more sections of the transmission line to another one or more sections of the transmission line.

[0110] Example 21. The machine-readable storage medium of Example 19, wherein the predetermined frequency is less than or equal to a cutoff frequency of the one or more LC filters of the one or more segments.

[0111] The abstract is provided to enable the reader to ascertain the nature and gist of the technical disclosure. It should be understood that the submitted abstract will not be used to limit the scope or meaning of the claims. The following claims are hereby incorporated into this detailed description, and each claim stands on its own as a separate example.

Claims

1. A system comprising: a chamber comprising a first region and a second region, the chamber being configured to generate and contain a plasma within the second region; a transmission line located in the first region, the transmission line comprising a plurality of sections, wherein a single section of the plurality of sections comprises one or more LC filters, wherein the one or more LC filters have respective cutoff frequencies, and wherein the transmission line comprises a transmission line input; and a signal source electrically coupled to the transmission line input end to feed an input signal to the transmission line input end; Wherein the one or more LC filters pass low frequency components of the input signal but localize high frequency components of the input signal to selected sections of the transmission line. 2 . The system of claim 1 , wherein the first region is separated from the second region by a dielectric window.

3. The system of claim 1, wherein the low frequency components are passed by the one or more LC filters to uniformly apply the low frequency components to the transmission line.

4. The system of claim 1, wherein the high frequency components are localized to the selected section of the transmission line by selection of the respective cutoff frequencies of the one or more LC filters. 5 . The system of claim 1 , wherein the selected section in which the high frequency component is localized is switched by a change in the frequency of the input signal fed to the transmission line.

6. The system of claim 1, wherein the voltage of the input signal is changed to change the voltage of the low frequency component uniformly applied to the transmission line.

7. The system of claim 1, wherein a voltage of the input signal is changed to change a voltage at the selected section where the high frequency component is localized.

8. The system of claim 1, wherein a cutoff frequency of the one or more LC filters decreases as they are located further downstream in the transmission line.

9. The system of claim 1, wherein the respective cutoff frequencies of the one or more LC filters decrease as the input signal propagates along the transmission line.

10. A system for modulating the spatial distribution and ion energy of a plasma, the system comprising: a chamber comprising a first area and a second area separated by a partition window; a transmission line located in the first region, the transmission line comprising a plurality of sections, wherein a single section of the plurality of sections comprises one or more LC filters, the one or more LC filters having respective cutoff frequencies, the transmission line having a transmission line input end; and a signal source electrically coupled to the transmission line input end to feed an input signal to the transmission line; wherein the one or more LC filters pass low frequency components of the input signal but localize high frequency components of the input signal to selected sections of the transmission line; and Wherein the spatial distribution and ion energy of the plasma in the second region are modulated in a region adjacent to the selected section of the transmission line. The system of claim 10 , wherein the separation window comprises a dielectric.

12. The system of claim 10, wherein the spatial distribution of the plasma is modulated by variations in the voltage of the input signal. 13 . The system according to claim 10 , wherein the selected section in which the high frequency component is localized is switched by a change in a frequency of the input signal.

14. The system of claim 10, wherein the voltage of the input signal is changed to change the voltage of the low frequency component on the transmission line.

15. The system of claim 10, wherein the voltage of the input signal is varied to vary the voltage across the selected segment in which the high frequency component is localized.

16. A method for modulating the spatial distribution and ion energy of a plasma, the method comprising: providing a chamber comprising a first region and a second region, wherein the first region comprises a transmission line having a plurality of segments, wherein a single segment of the plurality of segments comprises one or more LC filters; generating the plasma in the second region; selecting a portion of the second region where the plasma will be modulated; feeding an input signal of a predetermined frequency to the transmission line to localize a generated voltage at one or more of the plurality of sections adjacent to the selected portion of the second region; as well as The amplitude of the input signal is varied to adjust the generated voltage.

17. The method of claim 16, further comprising varying a frequency of the input signal to switch the localized generated voltage from one or more sections of the transmission line to another one or more sections of the transmission line.

18. The method of claim 16, wherein the predetermined frequency is less than or equal to a cutoff frequency of the one or more LC filters of the selected section.

19. A machine-readable storage medium having machine-executable instructions which, when executed, cause one or more machines to perform a method comprising: generating a plasma in a chamber comprising a first region and a second region, wherein the first region comprises a transmission line having a plurality of segments, wherein a single segment of the plurality of segments comprises one or more LC filters, wherein the second region comprises the plasma; selecting a portion of the second region where the plasma will be modulated; feeding an input signal of a predetermined frequency to the transmission line to localize a generated voltage at one or more of the plurality of sections adjacent to the selected portion of the second region; as well as The amplitude of the input signal is varied to adjust the generated voltage.

20. The machine-readable storage medium of claim 19, wherein the method further comprises varying a frequency of the input signal to switch the localized generated voltage from the one or more sections of the transmission line to another one or more sections of the transmission line.

21. The machine-readable storage medium of claim 19, wherein the predetermined frequency is less than or equal to a cutoff frequency of the one or more LC filters of the one or more segments.

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