High-voltage filter assembly

Abstract

The embodiments described herein are applicable for use in all types of plasma-assisted or plasma-enhanced processing chambers and also for methods of plasma-assisted or plasma-enhanced processing of substrates. More specifically, embodiments of the present disclosure include a broadband filter assembly, also referred to herein as a filter assembly, configured to reduce and / or prevent RF leakage current from being transmitted from one or more RF-driven components to ground through other electrical components that are directly or indirectly electrically coupled to the RF-driven components and ground, having a high input impedance (low current loss) to enable compatibility with shaped DC pulse bias applications.

Description

Technical Field

[0001] The embodiments described herein generally relate to plasma processing chambers used in semiconductor manufacturing. Background Art

[0002] Description of Related Art

[0003] Reliably producing high aspect ratio features is one of the key technical challenges for next-generation very large scale integration (VLSI) and ultra large scale integration (ULSI) semiconductor devices. One method of forming high aspect ratio features uses a plasma-assisted etching process (such as a reactive ion etching (RIE) plasma process) to form high aspect ratio openings in a material layer (such as a dielectric layer) of a substrate. In a typical RIE plasma process, a plasma is formed in an RIE processing chamber and ions from the plasma are accelerated towards the substrate surface to form an opening in a material layer disposed below a mask layer formed on the substrate surface.

[0004] Current challenges for plasma processing chambers and processes include controlling critical dimension uniformity during plasma processing, which requires heating the electrostatic chuck assembly in a controlled manner. A multi-zone heating assembly embedded in a dielectric material is used to heat the electrostatic chuck assembly. A typical reactive ion etching (RIE) plasma processing chamber includes a radio frequency (RF) bias generator and a metal bottom plate. The RF bias generator supplies an RF voltage to a "power electrode", and the metal bottom plate is embedded in a substrate support assembly, which is more commonly referred to as a "cathode". The powered RF bias electrode is capacitively coupled to the multi-zone electrostatic chuck heating assembly via a layer of dielectric material (e.g., a ceramic material), and the dielectric material layer is part of the ESC assembly. The strong capacitive coupling between the power electrode and the multi-zone electrostatic chuck heating provides a path for a large amount of RF current to flow to ground, which results in the loading of the RF bias waveform and the loss of RF power. An undesirably large RF current from RF-driven components to grounded hardware components can cause many undesirable effects, which include reducing the amount of RF power that can be effectively supplied to the power electrode (i.e., reducing RF transmission efficiency), potentially creating personnel safety issues, and potentially causing unwanted damage to auxiliary electrical and hardware components. The ability to prevent these undesirable effects becomes more difficult to achieve when the RF power supplied to the power electrode includes a wide range of RF frequencies. Most traditional RF filtering techniques are tuned to block a narrow range of frequencies supplied by the RF power to prevent the generated RF energy from damaging external electrical components and auxiliary electrical components connected to the RF-driven circuit. As the aspect ratio of semiconductor elements becomes higher, higher ion energies are required to etch these features. To achieve higher ion energies, there is a trend towards lower frequencies and higher powers, which makes filter design more challenging. Specifically, shaped DC pulses with low frequencies and a wide spectrum can be used, which are the most difficult to filter using traditional filter designs.

[0005] Accordingly, there is a need for devices and methods for minimizing and / or preventing an undesirably large RF current from being delivered to ground through one or more grounded chamber hardware components. SUMMARY OF THE INVENTION

[0006] In one example, a filter component is disclosed. The filter component includes a plurality of impedance generating elements that are electrically coupled in series between an input end and an output end of the filter component. The filter component further includes a first ground impedance generating element. The filter component further includes a second ground impedance generating element. The impedance generating elements are electrically coupled together in series via a first conductive lead and a second conductive lead. Each of the impedance generating elements includes a common mode choke formed by winding the first conductive lead and the second conductive lead around a toroidal core. The first ground impedance generating element is coupled to ground and is coupled to the first conductive lead at a point between two adjacent serially connected impedance generating elements. The second ground impedance generating element is coupled to ground and is coupled to the second conductive lead at a point between two adjacent serially connected impedance generating elements.

[0007] In another embodiment, a plasma processing chamber is disclosed. The plasma processing chamber includes a bias electrode disposed within a substrate support. The bias electrode is configured to be driven by a power generator. The plasma processing chamber further includes a conductive element disposed within the substrate support and positioned at a distance from the bias electrode. The plasma processing chamber further includes a filter component. The filter component includes a plurality of impedance generating elements that are electrically coupled in series between an input end and an output end of the filter component. The filter component further includes a first ground impedance generating element. The filter component further includes a second ground impedance generating element. The impedance generating elements are electrically coupled together in series via a first conductive lead and a second conductive lead. Each of the impedance generating elements includes a common mode choke formed by winding the first conductive lead and the second conductive lead around a toroidal core. The first ground impedance generating element is coupled to ground and is coupled to the first conductive lead at a point between two adjacent serially connected impedance generating elements. The second ground impedance generating element is coupled to ground and is coupled to the second conductive lead at a point between two adjacent serially connected impedance generating elements. The first conductive lead and the second conductive lead connect the conductive element to an external electrical component. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In order to enable a manner of understanding the above-described features of the present disclosure in detail, a more specific description of the present disclosure briefly summarized above may be obtained with reference to the embodiments, some of which are illustrated in the drawings. However, it should be noted that the drawings only illustrate typical embodiments of the present disclosure and should not be considered as limiting the scope of the present disclosure, since the present disclosure may admit other equivalent embodiments.

[0009] Figure 1Is a schematic cross-sectional view of an exemplary processing chamber configured to practice the methods described herein, according to one embodiment.

[0010] Figure 2 Is a schematic cross-sectional view of an example of a substrate support assembly, according to one embodiment.

[0011] Figure 3 Is a schematic diagram of a filter assembly, according to one embodiment, the filter assembly being coupled to one or more electrical components disposed within a plasma processing chamber.

[0012] Figure 4 Is a schematic diagram of a filter assembly, according to one embodiment, the filter assembly being coupled to one or more electrical components disposed within a pulsed DC power delivery system disposed within a plasma processing chamber.

[0013] For ease of understanding, wherever possible, the same reference numerals are used to denote the same elements in the drawings. It is contemplated that elements and features in one embodiment may be beneficially incorporated into other embodiments without further recitation. Detailed Description

[0014] The embodiments described herein are applicable for use in all types of plasma-assisted or plasma-enhanced processing chambers, and also to methods of plasma-assisted or plasma-enhanced processing of substrates. More specifically, embodiments of the present disclosure include a broadband frequency filter assembly, also referred to herein as a filter assembly, the broadband frequency filter assembly being configured to reduce and / or prevent RF leakage current from one or more RF-driven components to ground through other electrical components that are directly or indirectly electrically coupled to the RF-driven components and ground.

[0015] Figure 1 Is a schematic cross-sectional view of a processing chamber 100 configured to perform a plasma process within a processing volume 106 of the processing chamber 100 by using a source assembly 140. In this embodiment, the processing chamber 100 is a plasma processing chamber, such as a reactive ion etching (RIE) plasma chamber. In some other embodiments, the processing chamber is a plasma-enhanced deposition chamber, such as a plasma-enhanced chemical vapor deposition (PECVD) chamber, a plasma-enhanced physical vapor deposition (PEPVD) chamber, or a plasma-enhanced atomic layer deposition (PEALD) chamber. In some other embodiments, the processing chamber is a plasma treatment chamber or a plasma-based ion implantation chamber, such as a plasma doping (PLAD) chamber. Herein, as Figure 1As shown, the processing chamber 100 includes a source assembly 140, and the source assembly 140 includes an inductively coupled plasma (ICP) source electrically coupled to a radio frequency (RF) power supply 142 through an RF matching circuit 141. In other embodiments, the source assembly 140 is a capacitively coupled plasma (CCP) source, such as a source electrode (not shown) disposed in the processing volume 106 facing the substrate support 111, where the source electrode is electrically coupled to an RF power supply (not shown).

[0016] The processing chamber 100 includes a chamber body 102, and the chamber body 102 includes a chamber lid 123, one or more sidewalls 122, and a chamber base 124. The chamber lid 123, one or more sidewalls 122, and the chamber base 124 define the processing volume 106. A gas inlet 116 disposed through the chamber lid 123 is configured to supply one or more processing gases from a processing gas source 120 to the processing volume 106, and the processing gas source 120 is in fluid communication with the processing volume 106. Herein, the power supply 142 is configured to ignite and sustain a processing plasma 107 from the processing gas, including one or more induction coils 104 disposed outside the processing volume 106 near the chamber lid 123. The power supply 142 is used to ignite and sustain the plasma 107 using the processing gas and the electromagnetic field generated by the induction coils 104 and the RF power supply 142. The processing volume 106 is fluidly coupled to one or more dedicated vacuum pumps through a vacuum outlet 127, and the one or more dedicated vacuum pumps maintain the processing volume 106 at a condition below atmospheric pressure and evacuate the processing gas and / or other gases from the processing volume 106. A substrate support assembly 117 disposed in the processing volume 106 is disposed on a support shaft 138, and the support shaft 138 extends sealingly through the chamber base 124.

[0017] The substrate 110 is loaded into and removed from the processing volume 106 through an opening (not shown) in one of the one or more sidewalls 122, and the opening is sealed with a door or valve (not shown) during plasma processing of the substrate 110. Herein, the substrate 110 is transferred to and from a receiving surface 115 (e.g., a substrate support surface) of the substrate support 111, and the substrate support 111 may include an ESC substrate support 111A using a lift rod system (not shown).

[0018] The substrate support 111 includes a support base 111B and an ESC substrate support 111A that is thermally coupled to and disposed on the support base 111B. The support base 111B is electrically isolated from the chamber base 124 by an insulating plate 111C and a ground plate 137, and the ground plate 137 is inserted between the insulating plate 111C and the chamber base 124. Generally, during substrate processing, the support base 111B is used to regulate the temperature of the ESC substrate support 111A and the substrate 110 disposed on the ESC substrate support 111A. In some embodiments, the support base 111B includes one or more cooling channels (not shown) disposed in the support base 111B, and the one or more cooling channels are fluidly coupled to and in fluid communication with a coolant source (not shown), such as a refrigerant source or a water source having a relatively high electrical resistance. Herein, the support base 111B is formed of a corrosion-resistant thermally conductive material, such as a corrosion-resistant metal, such as aluminum, an aluminum alloy, or stainless steel, and the support base 111B is thermally coupled to the substrate support by an adhesive or by mechanical means.

[0019] Generally, the ESC substrate support 111A is formed of a dielectric material, such as a bulk sintered ceramic material, such as a corrosion-resistant metal oxide or metal nitride material, such as aluminum oxide (Al2O3), aluminum nitride (AlN), titanium oxide (TiO), titanium nitride (TiN), yttrium oxide (Y2O3), a mixture of the foregoing, or a combination of the foregoing. In some embodiments herein, the ESC substrate support 111A further includes a bias electrode 112 embedded in the dielectric material of the ESC substrate support 111A. In one configuration, the bias electrode 112 is a chucking pole that is used to fix (chuck) the substrate 110 to the receiving surface 115 of the ESC substrate support 111A and to bias the substrate 110 relative to the processing plasma 107. Generally, the bias electrode 112 is formed of one or more conductive parts, such as one or more metal meshes, foils, plates, or a combination thereof. Herein, the bias electrode 112 is electrically coupled to a high-voltage module 155 using an electrical conductor, such as a transmission line 151, and the high-voltage module 155 supplies a chucking voltage to the bias electrode 112, such as a static DC voltage between about -5000V and about 5000V.

[0020] In some embodiments, the ESC substrate support 111A includes a heater element 113, such as a resistive heating element embedded in the dielectric material of the ESC substrate support 111A. Due to resistive heating generated by AC power transmitted through one or more conductive elements 114, the heater element 113 is used to generate heat within the ESC substrate support 111A by using an AC power source 165, and one or more conductive elements 114 are embedded within the material used to form the ESC substrate support 111A. In one embodiment, one or more conductive elements 114 are spaced apart from the bias electrode 112 by a certain distance and are thus not directly connected to the bias electrode 112. As will be discussed in conjunction with Figure 2 As further discussed, the heater element 113 may include a plurality of heating regions, such as an internal heater region 113A including a first conductive element 114A and an external heater region 113B including a second conductive element 114B.

[0021] In one embodiment of the processing chamber 100, a filter assembly 160 is disposed between the AC power source 165 and one or more conductive elements 114 to prevent any RF leakage provided from the RF-biased bias electrode 112 to one or more conductive elements 114 from flowing into the AC power source 165 and damaging the internal components of the AC power source 165 and / or creating an unsafe condition for the user of the processing tool. The configuration of the filter assembly 160 is discussed in more detail below.

[0022] The bias electrode 112 is spaced apart from the substrate receiving surface 115 of the ESC substrate support 111A by a dielectric material layer of the ESC substrate support 111A and is thus spaced apart from the substrate 110. Generally, the thickness of the dielectric material layer is between about 0.1 mm and about 1 mm, such as between about 0.1 mm and about 0.5 mm, for example about 0.3 mm. Herein, the bias electrode 112 is electrically coupled to a power generator 150 using an external conductor, such as a transmission line 151. The power generator 150 can be a direct current (DC) power generator, a low-frequency RF power generator, or a shaped pulse DC bias power generator. One form of a pulsed DC power generator is described further below. The thickness of the dielectric material and layer formed between the bias electrode 112 and the substrate receiving surface 115 can be selected such that the capacitance C3 of the dielectric material layer ( Figure 2 ) is between about 5 nF and about 12 nF, for example between about 7 nF and about 10 nF.

[0023] The processing chamber 100 further includes a system controller 134. The system controller 134 herein includes a central processing unit (CPU), a memory, and support circuitry. The system controller 134 is used to control a process sequence for processing the substrate 110, including the substrate biasing method described herein. The CPU is a general computer processor configured for use in an industrial setting to control the processing chamber and associated sub-processors. The memory described herein includes random access memory, read-only memory, a floppy disk or hard disk drive, or other forms of digital storage (local or remote). The support circuitry is coupled to the CPU in a conventional manner and includes a cache, a clock circuit, an input / output subsystem, a power supply, etc. and combinations thereof. Software instructions and data can be encoded and stored in the memory for instructing the processor in the CPU. Programs (or computer instructions) readable by the system controller 134 determine which tasks can be performed by components in the processing chamber 100. Preferably, the program readable by the system controller 134 includes code that, when executed by the processor, performs tasks related to monitoring and executing the electrode biasing scheme described herein. The program will include instructions for controlling various hardware and electrical components within the processing chamber 100 to perform various process tasks and various process sequences for implementing the electrode biasing scheme described herein.

[0024] Figure 2 is Figure 1 A schematic side cross-sectional view of the substrate support 111 and portions of various support electrical components as shown. As previously discussed, the heater element 113 embedded within the ESC substrate support 111A includes a plurality of heating zones, such as an internal heater zone 113A including a first conductive element 114A and an external heater zone 113B including a second conductive element 114B. A first side of the first conductive element 114A is coupled to a first conductive lead 211, and a second side of the first conductive element 114A is coupled to a second conductive lead 212. The first conductive lead 211 and the second conductive lead 212 are connected to a first power supply 165A through a first filter assembly 160A. Similarly, a first side of the second conductive element 114B is coupled to a first conductive lead 221, and a second side of the second conductive element 114B is coupled to a second conductive lead 222. The first conductive lead 221 and the second conductive lead 222 are connected to a second power supply 165B through a second filter assembly 160B. Although Figure 2It includes a first power supply 165A and a second power supply 165B. However, this configuration is not intended to limit the scope of the present disclosure provided herein, because any number of power delivery elements can be used to separately control the power delivered to the first heating element 114A and the second heating element 114B. The power supply 165 or the power supplies 165A and 165B, as well as the conductive elements 114 or the first conductive element 114A and the second conductive element 114B, are generally configured to generate power between approximately 5000 watts and approximately 15,000 watts to heat the substrate support 111 to a desired temperature. Thus, in one example, the power supply 165 or the power supplies 165A and 165B are configured to deliver power between approximately 5000 watts and approximately 15000 watts at a voltage of 208 volts, and thus the conductive leads 211, 212, 221, and 222 generally require large-gauge wires, such as shielded wires of at least 10AWG to 14AWG. In one embodiment, the conductive leads 211, 212, 221, and 222 include wires having a cross-sectional area greater than or equal to 14AWG.

[0025] During operation, the power generator 150 is configured to provide a nanosecond DC pulse to the bias electrode 112, or in some configurations, is configured to provide RF power to the bias electrode 112, and the bias electrode 112 is capacitively coupled to the plasma 107 through a plurality of series capacitors, and the plurality of series capacitors may include an ESC capacitor C3 and a substrate capacitor C2. Due to the formed plasma and the plasma sheath formed at the chamber wall and on the substrate 110, the plasma 107 will generally have an impedance Z p , the impedance Z p includes a series of complex impedances. The dielectric layer in the electrostatic chuck and the substrate 110 (e.g., a 0.8 mm thick doped silicon plate having a capacitance C2 > 10 nF) separate the bias electrode 112 from the plasma 107 and are represented by capacitors C3 and C2 in the Figure 2 circuit. Since the substrate capacitance C2 is generally very large (> 10 nF), or the substrate can be conductive (infinite capacitance), the series capacitance is mainly determined by the actual ESC capacitor C3 (e.g., ~ 6.8 nF). The bias electrode 112 is also capacitively coupled to the first conductive element 114A and the second conductive element 114B, as Figure 2They are respectively represented by capacitors C4 and C5. The capacitive coupling between the bias electrode 112 and the first conductive element 114A and the second conductive element 114B will cause RF leakage current (or also referred to as noise current herein) to travel through the conductive leads 211, 212, 221, and 222 to their respective first filter assemblies 160A and second filter assemblies 160B. Therefore, the first filter assembly 160A and the second filter assembly 160B are positioned and configured to filter out these unwanted RF leakage currents in order to prevent the generated RF current from damaging either of the power supplies 165A and 165B and / or causing personnel safety issues.

[0026] Figure 3 is a schematic diagram of a filter assembly 160( Figure 1 ) coupled between a conductive element 114 and a power supply 165 disposed within a plasma processing chamber according to one embodiment. Figure 4 is a schematic diagram of a filter assembly 160 according to one embodiment, the filter assembly 160 being coupled between a conductive element 114 and a power supply 165 disposed within a plasma processing chamber 100. As discussed above, the filter assembly 160 is positioned and configured to prevent RF leakage current transferred from the bias electrode 112 to the conductive element 114 from reaching the power supply 165. The filter assembly 160 includes a plurality of impedance generating elements Z i , a plurality of impedance generating elements Z i are connected together between an input terminal 201 and an output terminal 202 via a conductive lead 211 and a conductive lead 212. The filter assembly 160 further includes a ground impedance element 305, the ground impedance element 305 being connected to ground and connected to the conductive lead 211 or the conductive lead 212 at a point between the last two of the connected impedance generating elements (such as Figure 3 the impedance generating elements Z4 and Z5 in).

[0027] In one embodiment, as Figure 3 and Figure 4 shown, the plurality of impedance generating elements includes five impedance generating elements Z1, Z2, Z3, Z4, and Z5 connected in series via a conductive lead 211 and a conductive lead 212. Generally speaking, the plurality of impedance generating elements includes at least two impedance generating elements, each of which includes at least an inductive element (L). As Figure 4 shown, each of the impedance generating elements includes a “real” inductive element (L), the inductive element (L) including the resistance (R) of the wire in the winding and having a self-capacitance (C). The ground impedance element 305 will include a capacitive element (C) and a resistive element (R) connected in series between one of the conductive lead 211 or the conductive lead 212 and ground. It will be noted that for modeling purposes, Figure 4The inductance (L 17 ) found in the grounding impedance element 305 as shown has been added to account for the windings of the wiring connecting the capacitive and resistive elements and is thus not a discrete added element. In one embodiment, the impedance of each of the plurality of impedance generating elements increases from a first impedance generating element Z1 near the input terminal 201 to the impedance generating element (e.g., Figure 3 the impedance generating element Z4 in) before the grounding impedance element 305. In one example, the impedance of the impedance generating elements increases (e.g., inductance elements L1 < L2 < L3 < L4), and the impedance of the last impedance generating element Z5 is higher than the impedance of element 305. In one embodiment, the inductance element (L) in each of the impedance generating elements increases such that L 10 < L 11 < L 12 < L 13 , as Figure 4 shown.

[0028] In another embodiment, at least two of the impedance generating elements connected in series have the same impedance value. In one example, the first impedance generating element Z1 and the second impedance generating element Z2 each have a first impedance value, and the third impedance generating element Z3 and the fourth impedance generating element Z4 each have a second impedance value different from the first impedance value. In this example, the first impedance value is preferably less than the second impedance value.

[0029] In some embodiments, the impedance generating element Z iEach includes a common-mode choke formed by winding conductive leads 211 and 212 around a toroidal core in a "common-mode" configuration. In one example, the toroidal core is a core containing toroidal ferrite, but the core can also be made of other high-permeability materials. In a common-mode winding configuration, RF leakage current (noise current) travels on both conductive leads 211 and 212 in the same direction (i.e., from input terminal 201 to output terminal 202), while the AC current provided from power supply 165 to generate heat in conductive element 114 flows in a direction opposite to the winding direction of conductive leads 211 and 212 on the toroidal coil. Two or more windings in the common-mode choke are arranged such that the common-mode current generates a magnetic field opposite to any increase in the common-mode current. In one embodiment, the impedance of the impedance generating element is adjusted by varying the number of turns of the winding, selecting a toroidal coil containing a material with a different magnetic permeability (μ), and / or both of the above. It is believed that by including a plurality of impedance generating elements each having a different impedance from filter assembly 160, the noise current (RF leakage current) traveling along conductive leads 211 and 212 can be effectively eliminated or minimized, such that the attached electrical components (e.g., power supply 165) are not affected by RF leakage. The different impedances of the impedance generating elements are used to block RF leakage currents having different frequencies. In one example, filter assembly 160 with impedance generating elements each having an increasing inductance (L) will tend to first block the higher-frequency noise currents and then incrementally block the noise currents having decreasing frequencies as the noise current passes through each successive impedance generating element Z i from input terminal 201 to output terminal 202.

[0030] The ground impedance element 305 is configured to have a desired RC value, and the last impedance element (e.g., Z5) is sized such that they will shunt any remaining noise current flowing on conductive lead 211 or conductive lead 212 to ground. In one embodiment, the last impedance element (e.g., Z5) is a common-mode choke including a toroidal core formed of a high-permeability material having a higher magnetic permeability (μ) than the material used to form the toroidal core in at least the first impedance generating element Z1. Generally, by selecting a desired number of impedance generating elements and their impedances to effectively block all the (multiple) RF leakage currents provided across the frequency range, the amount of current shunted to ground through ground impedance element 305 will be small, and thus any problems with leakage current provided to ground are avoided. In one embodiment, a combination of the desired number of impedance generating elements and the configuration of the (multiple) ground impedance elements 305 is used to limit the output current passed through ground impedance element 305 to less than 150 mA.

[0031] As described above, Figure 4 is a schematic view of a filter assembly 160 coupled between a conductive element 114 and a power supply 165, the power supply 165 being disposed within a plasma processing chamber 100. In this example, the power generator 150 is a pulsed bias generator that is configured to establish a pulsed voltage waveform at the bias electrode 112 to modify the characteristics of the plasma 107. The bias electrode 112 is separated from the substrate by a thin layer of dielectric material within the ESC assembly (e.g., a thin dielectric layer forming capacitor C3). The power generator 150 is configured to generate a pulsed voltage bias scheme that enables a substantially constant plasma sheath voltage to be maintained above the substrate 110 for approximately 90% of the substrate processing time, which results in a single (narrow) peak ion energy distribution function (IEDF).

[0032] An example of a pulsed voltage bias scheme provided by the power generator 150 can include: during a time interval when the internal power generator switch S is in the closed (on) position and maintains a substantially constant positive output voltage (equal to V m ), an output voltage (V0) having an amplitude of V m is transmitted. The voltage (V m ) can be up to several kilovolts (e.g., 0.1–10 kV). The time interval during which the switch remains in the closed (on) position and maintains a substantially constant positive output voltage is referred to as the “pulse width,” τ p , and τ p can be up to several tens of nanoseconds (e.g., 10–100 ns). Further, the time interval after the switch S transitions to the closed (on) position and the voltage (V m ) is achieved is referred to as the “rise time,” τ 上升 , and τ 上升 can also be on the order of several tens of nanoseconds (e.g., 25–50 ns). As the switch transitions from the open position to the closed position, the output voltage of the nanosecond pulse generator gradually increases until the output voltage reaches the voltage V m . Finally, the length of time between two consecutive transitions of the switch S from the open (off) position to the closed (on) position (or vice versa) is referred to as the “period,” T, and T is equal to the reciprocal of the pulse repetition frequency, which can be up to, for example, 400 kHz.

[0033] The broadband frequency filter assembly disclosed herein has significant advantages over conventional filter designs because the broadband frequency filter assembly disclosed herein is configured to filter out and minimize the transfer of leakage current provided over a wide frequency range. The configuration disclosed herein will also minimize the distortion of pulses provided to the bias electrode, minimize the leakage current transferred to ground at the output of the filter assembly to a value less than 150 mA, and due to the configuration of the impedance generating elements, the heat generated by the various impedance generating elements will be significantly lower than that of conventional filter designs similarly connected in the same plasma processing equipment. As discussed above, some of the desired impedance generating element configuration details will include, but are not limited to, the orientation of the impedance generating elements connected in series relative to the input of the filter assembly, the type of wiring and winding configuration of each of the impedance generating elements, and the selection of the material forming the toroidal cores in each of the impedance generating elements.

Claims

1. A filter component, comprising: A first conductive lead and a second conductive lead; An output terminal of the filter component, wherein the first conductive lead and the second conductive lead are configured to be electrically coupled to a power supply; An input terminal of the filter component; A first impedance generating element, the first impedance generating element being electrically coupled to the first conductive lead and the second conductive lead at the output terminal of the filter component; A plurality of second impedance generating elements, the plurality of second impedance generating elements being electrically coupled in series between the first impedance generating element and the input terminal of the filter component, each impedance generating element of the plurality of second impedance generating elements comprising: A portion of the first conductive lead wound around a portion of the toroidal core; and A portion of the second conductive lead wound around a portion of the toroidal core, wherein the impedance of each serially coupled second impedance generating element of the plurality of second impedance generating elements increases from the input terminal to a point disposed between the plurality of second impedance generating elements and the first impedance generating element; A first ground impedance generating element, the first ground impedance generating element being coupled to the first conductive lead at the point disposed between the plurality of second impedance generating elements and the first impedance generating element; and A second ground impedance generating element, the second ground impedance generating element being coupled to the second conductive lead at the point disposed between the plurality of second impedance generating elements and the first impedance generating element, wherein the impedance of the first impedance generating element is greater than the impedance of the first ground impedance generating element and the impedance of the second ground impedance generating element.

2. The filter component according to claim 1, wherein the first conductive lead is coupled to a first side of a resistive heating element, and the second conductive lead is coupled to a second side of the resistive heating element.

3. The filter component according to claim 1, wherein The impedance of the first impedance generating element comprises a first inductance; The impedance of the first ground impedance generating element comprises a second inductance; The impedance of the second ground impedance generating element comprises a third inductance; and Wherein the inductance magnitude of the first inductance is greater than the inductance magnitudes of the second inductance and the third inductance.

4. The filter component according to claim 1, wherein at least two of the plurality of second impedance generating elements have the same impedance value.

5. The filter component according to claim 4, wherein an AC power supply is configured to supply an AC current to the first conductive lead and receive a returned AC current on the second conductive lead.

6. The filter component according to claim 1, wherein the first conductive lead and the second conductive lead comprise wires having a cross-sectional area greater than or equal to 14 AWG wire.

7. The filter component according to claim 1, wherein The toroidal core of the first impedance element of the plurality of second impedance generating elements comprises a first material having a first magnetic permeability, and The toroidal core in the second impedance element among the plurality of second impedance generating elements includes a second material having a second magnetic permeability greater than the first magnetic permeability, and the first impedance element among the plurality of second impedance generating elements is positioned closer to the input end of the filter assembly, and the second impedance element among the plurality of second impedance generating elements is positioned closer to the output end of the filter assembly.

8. A plasma processing chamber, comprising: a bias electrode disposed within a substrate support, wherein the bias electrode is configured to be driven by a power generator; a conductive element disposed within the substrate support and positioned at a distance from the bias electrode; a filter assembly, the filter assembly including: a first conductive lead and a second conductive lead; an output end of the filter assembly, wherein the first conductive lead and the second conductive lead are configured to be electrically coupled to a power supply; an input end of the filter assembly; a first impedance generating element electrically coupled to the first conductive lead and the second conductive lead at the output end of the filter assembly; a plurality of second impedance generating elements electrically coupled in series between the first impedance generating element and the input end of the filter assembly, each second impedance generating element among the plurality of second impedance generating elements including: a portion of the first conductive lead wound around a portion of the toroidal core; and a portion of the second conductive lead wound around a portion of the toroidal core, wherein the impedance of each serially coupled second impedance generating element among the plurality of second impedance generating elements increases from the input end to a point disposed between the plurality of second impedance generating elements and the first impedance generating element; a first ground impedance generating element coupled to the first conductive lead at the point disposed between the plurality of second impedance generating elements and the first impedance generating element; and a second ground impedance generating element coupled to the second conductive lead at the point disposed between the plurality of second impedance generating elements and the first impedance generating element, wherein the impedance of the first impedance generating element is greater than the impedance of the first ground impedance generating element and the impedance of the second ground impedance generating element.

9. The filter assembly according to claim 1 or the plasma processing chamber according to claim 8, wherein the portion of the first conductive lead wound around the portion of the toroidal core and the portion of the second conductive lead wound around the portion of the toroidal core are wound in a common mode choke configuration.

10. The filter assembly according to claim 1 or the plasma processing chamber according to claim 8, wherein the conductive element includes a resistive heating element.

11. The filter assembly according to claim 1 or the plasma processing chamber according to claim 8, wherein the external electrical component includes an AC power supply.

12. The plasma processing chamber according to claim 8, wherein the impedance of each of the serially connected impedance generating elements increases incrementally from the input end of the filter assembly to the point between two adjacent serially connected impedance generating elements.

13. The plasma processing chamber according to claim 8, wherein at least two of the plurality of second impedance generating elements have the same impedance value.

14. The plasma processing chamber according to claim 8, wherein the first conductive lead and the second conductive lead comprise wires having a cross-sectional area greater than or equal to that of 14 AWG wire.

15. The plasma processing chamber according to claim 8, wherein the toroidal core in the first impedance element of the plurality of second impedance generating elements comprises a first material having a first magnetic permeability, and the toroidal core in the second impedance element of the plurality of second impedance generating elements comprises a second material, the second magnetic permeability of which is greater than the first magnetic permeability, and the first impedance element of the plurality of second impedance generating elements is positioned closer to the input end of the filter assembly, and the second impedance element of the plurality of second impedance generating elements is positioned closer to the output end of the filter assembly.

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